taxonID	type	description	language	source
03D887981861FFCE51B6FA025D0DF8B4.taxon	type_taxon	Type genus: Fabricia Blainville, 1828.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981861FFCE51B6FA025D0DF8B4.taxon	diagnosis	Diagnosis. Small-bodied, hemisessile polychaetes with eight thoracic and three, exceptionally two or four, abdominal chaetigers. Three pairs of radioles; branchial lobes not fused together mid-dorsally; radioles symmetrically or asymmetrically branched; ventral filamentous appendages present or absent; acellular radiolar skeleton absent or present; radiolar crown with branchial hearts; ventral lips absent. Anterior margin of anterior peristomial ring a low ridge dorsally and laterally; a triangular, rounded or rectangular lobe ventrally. Thoracic uncini acicular, with main fang followed by smaller teeth. Abdominal uncini with elongate manubrium and dentate region; dentate region with multiple rows of equal-sized teeth. Spermiogenesis in thoracic chaetigers; spermatids in large cluster with central cytophore; single, dorsal sperm duct present. Sperm nuclear projection present; sperm nuclear membrane thickening; extra-axonemal sheath present.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981861FFCE51B6FA025D0DF8B4.taxon	distribution	Distribution. Marine, brackish and freshwater benthic ecosystems; from intertidal to deep-sea; worldwide.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFCD51B6FF17596AFB3C.taxon	description	(Figure 4)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFCD51B6FF17596AFB3C.taxon	distribution	This new subfamily is proposed for all genera of Fabriciidae, except Echinofabricia, Manayunkia and Monroika (including Brandtika (see below )).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFCD51B6FF17596AFB3C.taxon	type_taxon	Type genus: Fabricia Blainville, 1828.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFCD51B6FF17596AFB3C.taxon	diagnosis	Diagnosis (apomorphies in italics). Small-bodied, hemisessile polychaetes with eight thoracic and three abdominal chaetigers (Fig. 4 A). Three pairs of bipectinated radioles, i. e., radioles symetrically branched (Fig. 4 B, C); acellular branchial skeleton present (Fig. 4 E); radiolar lobes completely separated from one another. Ventral filamentous appendages present or absent. Branchial hearts present (Fig. 4 A). Dorsal lips as low, narrow ridges or well-developed triangular or rounded lobes, sometimes poorly developed. Without ventral lips or lip-like processes. Anterior margin of anterior peristomial ring a low ridge dorsally and laterally; triangular, rounded or rectangular lobe ventrally with midventral ciliated patch (Fig. 4 D). Thoracic uncini acicular, with main fang followed by smaller teeth. Abdominal uncini with elongate manubrium and dentate region; dentate region with multiple rows of equal-sized teeth. Peristomial and pygidial eyes (Fig. 4 A). Spermiogenesis in thoracic chaetigers 3 – 8, 4 – 8 or 6 – 8; spermatids in large cluster with central cytophore; single, dorsal sperm duct present. Sperm nuclear projection present; sperm nuclear membrane thickening; extra-axonemal sheath present.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFCD51B6FF17596AFB3C.taxon	discussion	Remarks. With the designation of the Manayunkiinae subfam. nov. within the Fabriciidae, it is necessary to establish a subfamily for the remaining genera of Fabriciidae, Fabriciinae subfam. nov. Both subfamilies are sister taxa. In contrast to Manayunkiinae subfam. nov., Fabriciinae subfam. nov. have bipectinate radioles with an acellular supporting tissue. The feeding groove in Fabriciinae subfam. nov. is formed by 5 rows of ciliary cells, whereas in M. aestuarina it is formed by 9 to 10 rows of cells (see description of M. aestuarina, and Randel & Bick 2012; Tilic et al. 2021). Interestingly, the food groove of Sabellidae and Serpulidae is also composed of 5 ciliated cells with the same pattern of ciliation (Evenkamp 1931; Fitzsimonis 1965; Hanson 1949; Nicol 1930; Thomas 1940). When ventral filamentous appendages appear, they can be non-vascularized or vascularized and branched or unbranched. However, it is unclear whether the ventral filamentous appendages of both taxa are actually homologous. Whereas in the Manayunkiinae subfam. nov. a ciliated band occurs ventrally at the posterior margin of the anterior peristomial ring, in the Fabriciinae subfam. nov. a ciliated spot is present here. Number of abdominal segments is constant and pygidial eyes are always present. Transitional uncini or transitional chaetae as well as a brood chamber in females are absent.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFC351B6FA8C5B09FE28.taxon	discussion	This new subfamily is proposed for three genera, Echinofabricia Huang, Fitzhugh, & Rouse, 2011, Manayunkia Leidy, 1859 and Monroika Hartman, 1951. Brandtika Jones, 1974 is considered here as a junior synonym of Monroika (see Bick & Armendáriz 2021, Remarks and Discussion).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFC351B6FA8C5B09FE28.taxon	type_taxon	Type genus: Manayunkia Leidy, 1859	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFC351B6FA8C5B09FE28.taxon	diagnosis	Diagnosis (apomorphies in italics). Small-bodied, hemisessile polychaetes with eight thoracic and two, three or four abdominal chaetigers. Three pairs of pectinated radioles, i. e., radioles asymetrically branched; absence of an acellular branchial skeleton; radiolar lobes completely separated from one another. Unbranched vascularized ventral filamentous appendages and branchial hearts. Dorsal lips well developed. Ventral lips or lip-like processes absent. Anterior margin of anterior peristomial ring developed as a membranous collar with wide ventral lobe, narrowly separated mid-dorsally; ciliated band ventrally on posterior margin of anterior peristomial ring. Peristomial eyes present, pygidial eyes present or absent. Spermiogenesis in thoracic chaetigers 6 – 8, dorsal sperm duct present. Females with darkly pigmented spermathecae; brood chamber and transitional chaetae or transitional uncini may be present in females.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981862FFC351B6FA8C5B09FE28.taxon	discussion	Remarks. There are several characters that are only found in two or three other genera within the Sabellida. These are for example, asymmetrical branching pattern of the radioles, absence of an acellular branchial skeleton, presence of a ciliated band ventrally at the posterior margin on the anterior peristomial ring, presence of transitional chaetae or uncini on last three neuropodia of the thorax, and perhaps also presence of a brood chamber in females. These genera are Manayunkia, Monroika and perhaps also Echinofabricia. Fitzhugh (1989) described the surface of radioles and vascularized ventral filamentous appendages in Manayunkia and in Genus A (now: Echinofabricia) as minutely wrinkled. The lack of a distinct supporting tissue (= branchial skeleton) is most likely responsible for the fact that the branches of the radiolar crown contract during fixation. A wrinkled surface of the radioles and unbranched vascularised ventral filamentous appendages was also described in Monroika (Bick & Armendáriz 2021). Currently, little is known about the branching of the radiolar crown of Echinofabricia, and there is no description of transitional chaetae or transitional uncini and a brood chamber in this genus. But the asymmetrical branching of the radiolar crown and the lack of a true branchial skeleton are assumed to be ancestral characters. In fact, Manayunkia and Echinofabricia are in a plesiomorphic position in the phylogenetic tree of Fabriciidae (Huang et al. 2011). This position is confirmed by the genetic analyses in this paper (see Genetic account). Bick & Armendáriz (2021) already concluded that Brandtika could be a younger synonym of Monroika. Here, Brandtika is synonymized with Monroika, since in addition to presence of pseudo-spatulate chaetae, the presence of transitional chaetae, the presence of a large central tooth on abdominal uncini and the number of abdominal chaetigers also support the assignment of Brandtika to Monroika.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186CFFC051B6FDA25D6DFC78.taxon	type_taxon	Type species: Manayunkia speciosa Leidy, 1859, by monotypy.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186CFFC051B6FDA25D6DFC78.taxon	diagnosis	Diagnosis (after Bick et al. 2024, emended). Eight thoracic and three abdominal chaetigers. Three pairs of pectinated radioles present, i. e., radioles asymmetrically branched, only in the largest species arise 2 or more branches from a common base, so that the branches appear to be arranged in two rows; radiolar lobes completely separated from one another; acellular supporting tissue of radioles (= radiolar skeleton) consists of a thin layer of an extracellular matrix. Unbranched vascularized ventral filamentous appendages present. Dorsal lips erect, broadly rounded or tapered. Ventral lips or lip-like processes absent. Between base of branchial lobes and base of dorsal lips, ciliated food groove forms as a continuation of the ciliated epithelial cells of the radioles, which extends ventrally to the mouth opening; mouth opening bounded ventrally by the anterior peristomial ring lobe. Branchial heart dorsally in the peristomium. Anterior margin of anterior peristomial ring developed as a membranous collar with rectangular or rounded ventral lobe, narrowly separated mid-dorsally; ciliated band between anterior and posterior peristomial ring ventrally. Inferior thoracic notochaetae short, narrowly hooded or pseudo-spatulate. Thoracic uncini with rows of equal-sized or progressively smaller teeth above main fang; sexual dimorphism present: transitional chaetae or transitional uncini in chaetigers 6 – 8 present in females. Brood chamber usually present in females. Dentate region of abdominal uncini with multiple rows of equal-sized teeth; manubrium distinctly longer than dentate region. Peristomial eyes present, pygidial eyes absent. Spermiogenesis in chaetigers 6 – 8. Pigmented spermathecae in females at the base of the radiolar crown.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186CFFC051B6FDA25D6DFC78.taxon	discussion	Remarks. The number of radioles in Manayunkia is a recurring point of discussion. According to Bick (2020), all Fabriciidae, including Manayunkia, always have three pairs of radioles. However, it was also discussed whether Manayunkia could only have 2 pairs of radioles, but additionally a pair of slender, filiform appendages without branching in the dorsalmost position of the radiolar crown (e. g., Fitzhugh 1989). These appendages have also been referred to as ‘ Dorsallippenauswüchse’ (Zenkevitsch 1925), ‘ mediodorsal tentacles’ (Pettibone 1953) or ‘ displaced pinnules’ (Fitzhugh 1992). Bick (2020) also discussed the type of branching of the radiolar crown in the Fabriciidae. In Manayunkia, the branching of the radioles is pectinate. This pattern has also been demonstrated in Monroika (Bick & Armendáriz 2021). In M. baicalensis and M. godlewskii, by far the two largest valid species of this genus, a two-row arrangement of the branching of the radiolar crown has been described (e. g. Sitnikova et al. 1997; Zenkevitsch 1925). This interpretation did not take into account that two or more branches actually originate from a common base. A more detailed presentation of the different interpretations of the radiolar crown can be found in the Discussion at the end of this paper. Species of Fabriciinae subfam. nov. have an acellular radiolar skeleton (see above, and also Bick 2020; Randel & Bick 2012; Tilic et al. 2021) and a ciliated patch ventrally on the anterior peristomial ring (Fig. 4 D). Manayunkiinae subfam. nov., i. e. Manayunkia and Monroika and maybe also Echinofabricia Huang, Fitzhugh & Rouse, 2011, lack this ‘ supporting tissue’ (= radiolar skeleton). The extracellular matrix, which usually forms the supporting tissue of the radioles in Fabriciinae subfam. nov., is only poorly developed (Bick 2020, see Description of M. aestuarina (Fig. 7) and Discussion). Manayunkia and Monroika also have a ciliated band ventrally at the posterior margin on the anterior peristomial ring instead of a ciliated patch (Bick 2004, 2020; Bick & Armendáriz 2021). Darkly pigmented, sac-like spermathecae at the base of the radiolar crown in females have been described for several species (Bick et al. 2024; Rouse, 1995, 1996; Zenkevitsch 1925). In most or even all species, so-called transitional chaetae or transitional uncini (Bick 2020) may occur in the neuropodia of chaetigers 6 to 8 in females (Atkinson et al. 2020; Bick 2020; Bick et al. 2024; Sitnikova et al. 1997). Transitional chaetae represent an intermediate form of narrowly bended hooded chaetae and thoracic uncini that usually occur in this position. Transitional uncini are similar to normal thoracic uncini. However, the dentate region is elongated, a distinct main fang is absent and the entire upper surface is covered with a multitude of small, equally sized teeth. It is not yet known whether there is a character for the beginning of the reproductive period, i. e., whether they are only developed when females reach sexual maturity. It is assumed here that these chaetae or uncini do not occur in males. But this type of chaetae is also found in Monroika and Brandtika asiatica Jones, 1974 (now Monroika asiatica (Jones, 1974) n. comb.). This character is explained in more detail in the Discussion. A brood chamber in females has so far only been described in Manayunkia species. This brood chamber exists as at least two types. It is formed by wing-like protrusions of the integument of the brood chamber chaetigers, i. e. chaetigers 6 – 8, or by bulge-like protrusions on chaetigers 6 and 8 (see descriptions of various species).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186FFFC451B6FC525CCAFEB8.taxon	description	(Figures 3 top left, 5 – 8, 26 A)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186FFFC451B6FC525CCAFEB8.taxon	materials_examined	Material examined. Baltic Sea: 54 ° 01 ’ 60.00 ’’ N, 11 ° 29 ’ 59.99 ’’ E, depth 0.5 m, coll. 06.06.1996,> 100 specimens (ZSRO-P 1005), 54.02581 N, 11.531032 E, depth 0.5 m, coll. 22.04.1997,> 100 specimens (ZSRO-P 1008); 54 ° 01 ’ 26.2 ’’ N, 11 ° 29 ’ 23.9 ’’ E, depth 0.5 m, coll. 26.04.1982,> 100 specimens (ZSRO-P 1076).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186FFFC451B6FC525CCAFEB8.taxon	description	Description. Total length of specimens, including radiolar crown, between 2.5 and 6 mm; width on chaetiger two about 0.2 mm; length of radiolar crown about 0.25 – 0.35 mm; ratio between length of radiolar crown and body length, without radiolar crown, between 0.1 and 0.15. Body slender, slightly tapering posteriorly (Figs 3, 5 A, K). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages, surface of radioles and ventral filamentous appendages wrinkled (Figs 5 B, C, 6 A, 26 A); dorsal and median radioles unbranched, ventral radioles with two branches (Figs 6 B – F, 26 A); no morphological differences in the structure of the branches of the radiolar crown, except ventral filamentous appendages (Figs 5 C, 6 B); ventral filamentous appendages and branches of the radioles end at about same height or ventral filamentous appendages slightly longer (Fig. 5 A – C); radioles and vascularized ventral filamentous appendages rectangular, square or rounded in cross-section; extension about 25 – 40 x 30 – 45 µm and 45 – 60 x 55 – 70 µm, respectively (Fig. 6 B); ventral filamentous appendages with clearly visible blood vessel (Fig. 6 B – F). Epidermis of all branches of radioles and vascularized ventral filamentous appendages with ciliated and non-ciliated epithelial cells; epithelial cells of branches of radioles with microvilli and a 1 – 2 µm thick cuticle (Fig. 7 A, B); 9 – 10 epithelial cells with 3 – 12 cilia each constitute the shallow or even convex food groove of radioles adorally; most laterally located epithelial cells of food groove, each with 6 – 7 significantly longer laterofrontal cilia (Fig. 7 A, B); occasionally 2 – 3 aboral cilia present (Fig. 7 B, F); number of epithelial cells of radioles decreases from base to tip; cilia completely absent at the tip, microvilli and cuticle present (Fig. 7 E); epithelial cells with many mitochondria, intracellular glycogen and vacuoles; glycogen and vacuoles located almost exclusively basiepithelial (Fig. 7 A); aboral epithelial cells with longitudinal myofibrils forming a longitudinal muscles of branches of radioles; 1 – 3 intraepithelial nerves aborally, up to 3 intraepithelial nerves adorally; center of branches of radioles occupied by large coelomic cavity bordered by flat myoepithelial cells, about 1 µm wide (Fig. 7 A, B, D); between epidermal and myoepithelial cells an extracellular matrix, about 0.2 µm wide; extracellular matrix with irregularly arranged collagen fibres (Fig. 7 A – F); narrow cytoplasmic processes with a length of about 1 - 3 µm extend into coelomic cavity of branches of radioles (Fig. 7 D, F); dorsal lips developed as rounded lobes with a length of about 40 to 50 µm (Fig. 6 E, F). Peristomium slightly longer than first chaetiger, about as long as chaetiger 2, with anterior and posterior rings; anterior peristomial ring distinctly shorter than posterior ring (Fig. 5 A – C); anterior margin developed as a low membranous collar ventrally, narrowly separated mid-dorsally (Figs 5 B, C, 6 A); ciliated band on posterior margin of anterior peristomial ring ventrally (Figs 5 C, 6 A); border between anterior and posterior peristomial rings clearly visible all around (Figs 5 B, C, 6 A); one pair of rounded black peristomial eyes present (Fig 3); females with pigmented spermathecae. Metanephridia in peristomium and chaetigers 1 and 2. First thoracic chaetiger shorter than peristomium and second chaetiger; chaetigers 2 – 6 successively longer; chaetiger 8 shorter than chaetiger 7; first 3 or 4 thoracic chaetigers wider than long, chaetigers 4 or 5 – 8 distinctly longer than wide; abdomen about as long as chaetiger 7; first abdominal chaetiger longest, about twice as long as second one; abdominal chaetiger 3 slightly shorter than second, about as long as pygidium; Pygidium tapered or terminating as rounded lobe (Figs 3, 5 A, K); pygidial eyes absent; borders between thoracic and abdominal chaetigers usually clearly visible (Figs 3, 5 A, K). First chaetiger with about 1 – 2 short, and 2 – 3 elongate, narrowly hooded notochaetae, neuropodial uncini absent; notopodia of chaetigers 2 – 8 superiorly with 3 – 6 elongate, narrowly hooded chaetae, inferiorly with 1 – 2 (rarely 3) pseudo-spatulate chaetae on chaetigers 2 – 5 and 1 – 3 short, narrowly hooded chaetae on chaetigers 6 – 8 (Fig. 5 E, F); neuropodia of chaetigers 2 – 8 (male) or 2 – 5 (female) with 5 – 8 uncini with main fang and apical with about 4 – 5 rows of progressively smaller teeth (Fig. 5 G); females with 5 – 12 transitional uncini on chaetigers 6 – 8, different from thoracic uncini on chaetigers 2 – 5; transitional uncini longer than regular thoracic uncini, without main fang, with a multitude of rows of small, equal-sized teeth (Fig. 5 H); abdominal neuropodia with 2 – 5 elongate and 1 – 2 short, narrowly hooded chaetae (Fig. 5 D); abdominal notopodia with 15 – 22 uncini on chaetiger 9, 12 – 15 uncini on chaetiger 10, and 8 – 12 uncini on chaetiger 11, respectively; abdominal uncini with about 6 – 7 rows of equal-sized teeth, about 4 – 6 teeth per row (Fig. 5 I); manubrium about 3 times as long as dentate region. Females with shallow brood chamber on chaetigers 6 and 7 or 8, formed by wing-like protrusions of the integument of these chaetigers; brood chamber segments not elongated and chaetiger boundaries clearly visible. Fixed specimens usually translucent, however radiolar crown, anterior intestinal region and nephridia brownish in colour; ventral vascularised filamentous appendages of living animals greenish, due to colour of blood (Fig. 26 A).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186FFFC451B6FC525CCAFEB8.taxon	discussion	Remarks. Manayunkia aestuarina is the species of the genus with the largest area of distribution. Based on genetic studies, this species has at least a transatlantic distribution (Huang et al. 2011). However, whether the occurrence of Manayunkia specimens on the Pacific coast (Bishop 1984; Light 1969) and the Iberian Peninsula (López & Cepeda 2017) can actually be attributed to this species, or whether they are misidentifications, remains to be clarified. The individuals described as M. aestuarina by Harris (1970) from marine habitats of the Isles of Scilly, Great Britain, certainly do not belong to this species. These individuals lack pseudo-spatulate chaetae and the radiolar crown is also very different from that characteristic of M. aestuarina. The synonymisation of M. polaris with M. aestuarina assumed by Zenkevitsch (1935) and Hartman (1951) should also be critically reviewed. Manayunkia aestuarina is the species with the lowest number of branches of the radioles. At an early stage of larval development, the structure of the radiolar crown is already clearly recognizable. There are 3 radioles that originate from a common base. Only the ventral radiole divides into 2 branches, the other two remain unbranched (Fig. 8 A, B). All other Manayunkia species have more than 4 pairs of branches (see Table 2). In the literature, lengths of up to 4 – 6 mm (probably living individuals) are given for this species (e. g., Bourne 1883; Hartmann-Schröder 1996; Karling 1933; Zenkevitsch 1925). In the Baltic Sea, fixed specimens usually reach 2 mm, only some preserved specimens are slightly larger. The TEM examinations showed that the ECM as a possible radiolar skeleton is only very weakly developed. In Fabriciinae subfam. nov., on the other hand, the ECM is strongly developed adorally and can be described as a true supporting structure (Fig. 4 E). The number of cells forming the feeding groove also differs from those found in various Fabriciinae species (Randel & Bick 2012; Bick 2020; Tilic et al. 2021). This species is sexually dimorphic. In females, transitional uncini were found in chaetigers 6 – 8. In some other Manayunkia species, such transitional uncini or transitional chaetae have also been found in females (see Remarks for other species). The occurrence of transitional uncini in this species is described here for the first time. As these uncini differ very little from the regular thoracic uncini, it is difficult to observe them under the light microscope. This could explain why this type of uncini has not yet been described. The presence of a brood chamber in females is also described here for the first time. The number of thoracic and abdominal uncini increases with total length of specimens. Small specimens have hardly more than 20 uncini per body side in the three abdominal chaetigers, whereas adults have more than 50 (Bick 1995).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186FFFC451B6FC525CCAFEB8.taxon	distribution	Geographic distribution. This species is found in brackish waters of the North Atlantic, both on European and American coasts, and probably also on the Pacific coast of North America.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186FFFC451B6FC525CCAFEB8.taxon	biology_ecology	Biology. Abundances of more than one million specimens per square meter have been reported for M. aestuarina in suitable habitats (e. g., Bagheri & McLusky 1982; Bell 1982). Spermiogenesis occurs in chaetigers 6 to 8, and egg development in chaetiger 4. According to Forsman (1956) and Schütz (1965), M. aestuarina females are 3 – 5 times as numerous as males, but Bick (1996) found a sex ratio of approximately 1: 1 in the southern Baltic Sea. Manayunkia aestuarina females exhibit between two and four eggs. The reproduction of M. aestuarina is discontinuous, as neither embryos nor juvenile recruitment was observed during winter months (November to March) in a South Carolina salt marsh (Bell 1982). Reproduction also starts at the end of March / beginning of April in the southern Baltic Sea but is completed by the end of August, as no eggs or larvae are found in the female tubes after August (Bick 1996; Schütz 1965). Males reach reproductive maturity before females in the Baltic Sea (Bick 1996). Males with sperm and females with eggs have been observed in autumn and winter in the North Sea (Schütz 1965). On average, 4 eggs of approximately 200 – 300 µm in length and developing larvae are simultaneously found within a tube, with a maximum number of 16 occurring in the middle of the reproductive period. Bell (1982) observed 8 – 12 larvae per tube, each of which was in a different stage of development. The youngest stages generally occupied the anterior part of the tube, with the more advanced larvae behind them. All larvae faced the tube mouth, and all stages were joined by a mucous coating. The development of larvae may take two weeks (Forsman 1956), from two to four weeks (Bell 1982) or eight weeks (Bick 1996). Low temperatures delay the development time. The larvae leave the tube at a size of about 0.6 – 0.7 mm (Bick 1996). They do not crawl far from the female tube. The survival rate of juveniles is approximately 15 – 20 %, and the average age of this species is approximately one year (Bick 1996). High temperatures, lack of oxygen or other unfavourable parameters cause M. aestuarina to extend the posterior end out of the tube and perform circular movements. Not infrequently, the radiolar crown is then thrown off (Schütz 1965). Outside of the tubes, the worm encases itself in mucus and shows great chaetal activity in the search for a suitable substratum (Knight-Jones 1981). Manayunkia aestuarina has a range of feeding mechanisms, but is thought to be mainly a deposit feeder (Lewis 1968).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186FFFC451B6FC525CCAFEB8.taxon	biology_ecology	Ecology. Manayunkia aestuarina lives preferably in tubes in muddy to fine sand in shallow brackish water areas. The presence of peritrich ciliates as commensals was described for M. aestuarina from the Baltic Sea (Bick 2020). These were located on the first thoracic chaetigers in close proximity to the notopodia.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186BFFD951B6FE12589AF918.taxon	description	(Figures 3 top right, 9 – 10, 26 B)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186BFFD951B6FE12589AF918.taxon	materials_examined	Material examined. Western Australia, Yalgorup National Park, Lake Newnham, 32 ° 54 ’ 06.1 ’’ S, 115 ° 41 ’ 47.0 ’’ E, coll. 24.01.2014,> 50 specimens (WAM-V 8215 and WAM-V 8216).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186BFFD951B6FE12589AF918.taxon	description	Description. Total length of specimens, including radiolar crown, between 2.5 and 3.2 mm (but see Remarks); width on chaetiger 2 about 0.3 mm (but see also Remarks); length of radiolar crown max. 0.65 mm; ratio between length of radiolar crown and body length, without radiolar crown, between 0.2 and 0.25; body slender, slightly tapering posteriorly (Figs 3, 9 A, I). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages (Figs 9 A, 10 A, B, 26 B); surface of radioles and ventral filamentous appendages usually wrinkled (Fig. 9 A, but see Fig. 10 A); first dorsal radioles branch off from the branchial lobe, median and ventral radioles arise from a common base (Fig. 10 B – F); all radioles asymmetrical branched or pectinated (Fig. 10 A – F, 26 B); ventral radioles with 5 – 7, median and dorsal radioles with 4 – 6 branches (Fig. 10 B – D, 26 B); smaller specimens with only 2 – 3 branches per radiole; no morphological differences in the structure of the various branches of the radiolar crown, except ventral filamentous appendages (Fig. 10 B – F, 26 B); ventral filamentous appendages and branches of radioles end at about the same height or ventral filamentous appendages slightly longer (see Figs 9 A, 10 A); branches of radioles rectangular to square in cross-section, extension about 20 – 30 x 27 – 40 µm; vascularized ventral filamentous appendages oval, extension about 45 – 65 µm (Fig. 10 B – D); blood vessel in ventral filamentous appendages (Fig. 10 B – D); epidermis of radioles and vascularized ventral filamentous appendages adorally with ciliated and aborally with non-ciliated epthelial cells; ciliated cells constitute the food groove; center of branches of radioles occupied by a large cavity bordered by a narrow band of cells; dorsal lips developed as triangular lobes, rounded at upper margin, about 50 – 70 µm long, dorsal lips connect dorsal radioles with vascularized ventral filamentous appendages (Fig. 10 D – F). Peristomium slightly longer than first chaetiger, about as long as chaetiger 2, with anterior and posterior rings (Fig. 9 A); anterior peristomial ring distinctly shorter than posterior ring (Fig. 9 A); anterior margin of the anterior peristomial ring developed as a low membranous collar ventrally, narrowly separated mid-dorsally; ciliated band present ventrally on posterior margin of anterior peristomial ring (Figs 9 A, 10 A); border between anterior and posterior peristomial rings clearly visible (Figs 9 A, 10 A). Faecal groove dorsally deeply sunken in peristomial region, becoming considerably lower on first and following chaetigers; faecal groove shifts from dorsal to ventral midline at border between thorax and abdomen (Fig. 9 I). Metanephridia located in peristomium and first 2 chaetigers. First chaetiger shorter than peristomium and second chaetiger; chaetigers 2 – 6 each successively longer, chaetigers 7 and 8 successively shorter; first thoracic chaetigers wider than long, last 3 or 4 thoracic chaetigers distinctly longer than wide; abdominal chaetigers short, chaetiger 9 longest, chaetiger 10 and 11 decreasing in length (Figs 3, 9 I); pygidium about same length as chaetiger 10, terminating as rounded lobe or tapered; pygidial eyes absent; borders between thoracic chaetigers usually clear visible (Figs 3, 9 A). First chaetiger with about 1 – 2 short, and 2 – 3 elongate, narrowly hooded notochaetae, neuropodial uncini absent; notopodia of chaetigers 2 – 5 superiorly with 3 – 4 elongate, narrowly hooded and inferiorly with 2 – 3 pseudo-spatulate chaetae (Fig. 9 D); notopodia of chaetigers 6 – 8 superiorly with 3 – 4 elongate, narrowly hooded and 2 – 3 short, narrowly hooded chaetae (Fig. 9 E, G); neuropodia of chaetigers 2 – 5 (female) or 2 – 8 (male) with 4 – 6 (rarely 2, 3 or 7) uncini with main fang and apical with about 6 – 8 rows of progressively smaller teeth (Fig. 9 B); mature females with 4 – 6 transitional uncini on chaetigers 6 – 8, different from thoracic uncini on chaetigers 2 – 5 (Fig. 9 C, F, G); transitional uncini almost same size as regular thoracic uncini, main fang only indistinctly developed, i. e., less acute and more rounded, with a multitude of rows of small, almost equal-sized teeth (Fig. 9 C); abdominal neuropodia with 3 – 5 elongate, narrowly hooded chaetae (Fig. 9 I); abdominal notopodia with 16 – 20 uncini on chaetiger 9, 15 – 20 on chaetiger 10, and 10 – 13 on chaetiger 11, respectively (Fig. 9 H); abdominal uncini with about 5 – 6 rows of equal-sized teeth, about 4 – 6 teeth per row (Fig. 9 H); manubrium about three times as long as dentate region. Posterior end of pygidium tapered or rounded (Figs 3, 9 I). Radiolar crown and thorax greenish-black or brownish-green until chaetiger 6, then transparent; intestine dark coloured.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186BFFD951B6FE12589AF918.taxon	discussion	Remarks. Manayunkia athalassia is the only Manayunkia species with branched dorsal radioles. In all other species the dorsal radioles are unbranched (see Table 2). The specimens studied here were collected in Western Australia. Compared to the individuals from the type locality in South Australia, these individuals are somewhat smaller (3.2 mm long vs. 5 mm long, and 0.3 mm wide vs. 0.5 mm wide). In contrast, the number of thoracic and especially abdominal uncini is significantly greater. The specimens from the type locality have only 10 – 12 abdominal uncini per chaetiger. It is remarkable since larger specimens usually have more hooks and chaetae. Smaller specimens of M. athalassia have about 30 uncini per body side in the three abdominal chaetigers, whereas adults have slightly more than 50. It must therefore be clarified whether the specimens from South and Western Australia actually belong to one species. There is a sexual dimorphism in this species, or it could be a simultaneous hermaphrodite (Rouse et al. 2024). In females, transitional uncini were found on chaetigers 6 – 8 (see Remarks for other species). These uncini differ very little from the regular thoracic uncini. This may explain why this type of uncini has not been mentioned in the original description by Hutchings et al. (1981). It is not known if females of this species have a brood chamber.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186BFFD951B6FE12589AF918.taxon	distribution	Geographic distribution. This species occurs in ephemeral hypersaline salt lakes in South and Western Australia.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798186BFFD951B6FE12589AF918.taxon	biology_ecology	Biology. Manayunkia athalassia lives in colonies of up to 20 individuals (Hutchings et al. 1981). Females with oocytes about 250 x 100 µm in size were found in February and males with spermatocytes in March. The oocytes develop in chaetiger 4, and the spermatocytes in chaetiger 7 (Graeme Christie, pers. comm.) Ecology. Manayunkia athalassia lives in hypersaline lakes at salinities between 22 and 95 psu. Graeme Christie (pers. comm.) observed living specimens, motionless but still alive even at 185 ppt. In summer, these lakes can dry up and the temperature exceeds 40 ° C. The specimens then fall into a kind of rigidity or suspended animation. They could also be maintained in an aquarium of 82 psu for several month. The specimens occur in gelatinous tubes in soft clayed carbonate sediments which may contain shell debris of ostracods and gastropods (Hutchings et al. 1981).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981876FFDF51B6F8B259C9FC5C.taxon	description	(Figure 11)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981876FFDF51B6F8B259C9FC5C.taxon	materials_examined	Material examined. Russia, Lake Baikal: Aya Bay, depth 6 m, sandy bottom, coll. 09. July 2001, 4 specimens (complete male, female, juvenile and several fragments) (USNM 1128559).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981876FFDF51B6F8B259C9FC5C.taxon	description	Description (based on the descriptions of Nusbaum (1901), Sitnikova et al. (1997) and own observations). Total length of specimens, including radiolar crown, between 5 and 8 mm, usually 5 to 6 mm long; width about 0.6 – 0.8 mm; length of radiolar crown 0.5 – 1 mm; ratio between length of radiolar crown and body length, without radiolar crown, between 0.14 and 0.2; body slender, more or less distinctly elongated and tapering posteriorly; margins of thoracic chaetigers clearly visible, but barely visible on abdominal chaetigers (Fig. 11 A, E). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; surface of radioles and ventral filamentous appendages wrinkled; dorsal radioles unbranched, median and ventral radioles with a large number of branches, usually 2 (or more?) branches arise from a common base, so that the branches appear to be arranged in two rows; in total between about 30 and 62 branches (on average 50), rarely more; ventral filamentous appendages and almost all branches of the radioles end at about the same height (Fig. 11 B, C) Peristomium distinctly longer than first chaetiger, about as long as chaetiger 3, with anterior and posterior rings; border between anterior and posterior rings indistinct; anterior margin of anterior peristomial ring developed as a low membranous collar ventrally, narrowly separated mid-dorsally; faecal groove dorsally deeply sunken in peristomial region, becoming considerably lower on first and following chaetigers (Fig. 11 B, C); faecal groove shifts from dorsal to ventral midline at border between thorax and abdomen. First chaetiger shorter than peristomium; chaetigers 1 – 6 each successively longer, chaetigers 7 and 8 shorter again; first 4 thoracic chaetigers wider than long, last 3 thoracic chaetigers distinctly longer than wide; margins of chaetigers 6 – 8 often not clearly visible in females with brood chamber; abdominal chaetigers short, chaetiger 9 longest, chaetiger 10 and 11 decreasing in length; pygidium about same length as chaetiger 11, clearly elongated and pointed; pygidial eyes absent (Fig. 11 A – C, E). Notopodia of chaetigers 2 – 8 superiorly with about 15 – 20 elongate, narrowly hooded chaetae of about 0.3 – 0.4 mm in length, inferiorly with short, narrowly hooded chaetae; neuropodia of chaetigers 2 – 5 (females) or 2 – 8 (males) with 6 – 13 (on average 9) uncini with a main fang and apical with about 4 – 6 rows of progressively smaller teeth; length of uncini about 0.3 – 0.4 mm; abdominal neuropodia with 6 to 10 elongate and short narrowly hooded chaetae; abdominal notopodia with 28 – 40 uncini, about 0.1 mm long; mature females with transitional chaetae on neuropodia of chaetigers 6 – 8; brood chamber, formed by bulge-like protrusions ventrally on chaetigers 6 and 8, also present in females (Fig. 11 A, D). Radiolar crown and thorax until about chaetiger 6 pigmented, then transparent; gut dark coloured; fixed specimens completely without pigment.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981876FFDF51B6F8B259C9FC5C.taxon	discussion	Remarks. In addition to the original description of M. baicalensis by Nusbaum (1901), there are further detailed descriptions of this species by Zenkevitsch (1925) and Dybowski (1929). However, these descriptions can only be used with some reservations as Zenkevitsch (1925) has synonymised M. baicalensis with M. godlewskii, the characters of both species are obviously mixed. Dybowski's (1929) description of Trichosobranchella novobaicalensis Dybowski, 19289, probably does not separate the two species mentioned above either. The above-mentioned authors each gave a different number of branches of the radiolar crown. According to Nusbaum (1901), the number varies between 30 and 40 branches, according to Zenkevitsch (1925) between 48 and 72, juvenile individuals with a total of 24 branches, and according to Dybowski (1929) also between 48 and 72. The number of branches of the median and ventral radioles is relatively high, at least in comparison to most of the smaller species. This can possibly be explained by the fact that the branches divide further immediately after branching, so that 2 or even more branches could branch off from a common base. However, we were unable to investigate this with the material available to us. A small, 2.1 mm long juvenile had significantly fewer thoracic and abdominal chaetae and uncini than adults: 4 – 6 thoracic and 1 – 3 abdominal chaetae, and 3 – 4 thoracic and 8 – 15 abdominal uncini. A smaller number of chaetae and uncini in juveniles was also found in other species. The pygidium of this small specimen is also elongated but rounded. Sitnikova et al. (1997) compared M. baicalensis and M. godlewskii and described a third species, M. zenkewitschii, from Lake Baikal. The data for these three species are therefore the most reliable. Manayunkia baicalensis is characterised by an elongated and pointed pygidium. In the other two species from Lake Baikal, the pygidium is not elongated. In addition, the first 6 chaetigers are clearly pigmented. In M. zenkewitschii all chaetigers are pigmented, in M. godlewskii the pigment is almost completely absent or at most the first two chaetigers have pigment. A supposed subspecies of M. baicalensis, M. baicalensis hydani Slastnikov, 1940, was found in the Gyda River, Gyda Peninsula, on the Siberian coast of the Kara Sea (Slastnikov 1940). However, as there is no description of this subspecies, it must be considered a nomen nudum. In addition, M. baicalensis has only been found in Lake Baikal and in no other lakes in Siberia (see Pudovkina et al. 2016). It can therefore be assumed that this is a different species that has not yet been described. Manayunkia species from Lake Baikal exhibit also sexual dimorphism, which is evident in the presence of transitional chaetae or transitional uncini of chaetiger 6 – 8 in females and their absence in males, as well as the morphology of the posterior thoracic chaetigers. Chaetigers 6 to 8 are elongated in males, while in females bulge-like protrusions ventrally at chaetigers 6 and 8 are interpreted as the boundary of a brood chamber in which eggs and embryos develop.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981876FFDF51B6F8B259C9FC5C.taxon	distribution	Geographic distribution. Known only from Lake Baikal, Russia.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981876FFDF51B6F8B259C9FC5C.taxon	biology_ecology	Biology. The eggs develop in females in chaetiger 4 (Zenkevitsch 1925). They are oval, and have a length between 0.28 and 0.33 mm, and a width of 0.23 and 0.25 mm. The maximum number of eggs and juveniles of different developmental stages in a maternal tube was 36. We were able to count 25 eggs in the brood chamber of a female collected in July 2001, which was part of the loan from the NMNH (USNM 1128559). The main reproduction period is in July and August (Sitnikova et al. 1997). Ecology. Manayunkia baicalensis lives on sandy bottoms, among stones and boulders at depths between 0.8 and 80 m in Lake Baikal.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981870FFDD51B6F97B5CDAFC30.taxon	description	(Figure 12)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981870FFDD51B6F97B5CDAFC30.taxon	materials_examined	Material examined. Paratypes: Brazil, Canaea between Santos and Curityba, coll. 1954, 5 incomplete specimens (USNM 40710).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981870FFDD51B6F97B5CDAFC30.taxon	description	Description (based on the description of Banse (1956) and own observations). Total length of specimens, including radiolar crown, between 1.7 and 2.0 mm, (paratypes without radiolar crown only about 1.2 – 1.3 mm); width about 0.15 mm (paratypes 0.10 – 0.14 mm) (Fig. 12 A); length of radiolar crown about 0.3 mm (radiolar crown of paratypes about 0.15 mm long); ratio between length of radiolar crown and body length, without radiolar crown, between 0.18 and 0.21 (not determinable in paratypes). Body slender, posteriorly oval or tapered. Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; dorsal radioles unbranched, median radioles with 3 and ventral radioles with 4 branches (see Figure 4 a, b in Banse (1956 )); ventral filamentous appendages and branches of the radioles end at about the same height. Peristomium longer than first chaetiger, with longer anterior and shorter posterior rings; anterior margin of anterior peristomial ring as membranous collar ventrally, indented laterally, narrowly separated mid-dorsally; border between anterior and posterior peristomial rings clearly visible; one pair of black peristomial eyes. First chaetiger distinctly shorter than peristomium and second chaetiger, chaetigers 2 – 4 successively longer (Fig. 12 B), chaetiger 5 slightly shorter than chaetiger 4, chaetigers 6 and 7 significantly longer, chaetiger 8 shorter again; first 5 thoracic chaetigers wider than long, last 3 thoracic chaetigers distinctly longer than wide; borders between thoracic chaetigers clear visible (Fig. 12 A, B); abdominal chaetigers short, borders between these chaetigers indistinct; abdomen, including pygidium, in total about as long as chaetiger 8; pygidium about same length as chaetiger 10 (Fig. 12 C); pygidial eyes absent. First chaetiger with about 2 – 3 short, and 3 – 5 elongate, narrowly hooded notochaetae, neuropodial uncini absent; notopodia of chaetigers 2 – 5 superiorly with 4 – 5 elongate, narrowly hooded chaetae, 120 – 150 µm long, and inferiorly with 2 – 3 pseudo-spatulate chaetae, 75 – 90 µm long; notopodia of chaetigers 6 – 8 superiorly with 3 – 4 elongate, narrowly hooded and 2 short, narrowly hooded chaetae; neuropodia of chaetigers 2 – 8 with 5 – 7 (sometimes 8) uncini, 40 – 45 µm long, with main fang and apical with about 4 rows of progressively smaller teeth; abdominal neuropodia with 2 – 3 elongate chaetae, 120 – 130 µm long, and 1 – 2 short narrowly hooded chaetae; abdominal notopodia with about 20 uncini on chaetiger 9, 18 on chaetiger 10, and 15 on chaetiger 11; abdominal uncini, 20 – 22 µm long, with about 3 – 4 rows of equal-sized teeth, about 6 teeth per row; dentate region about 4 µm long; manubrium about four times as long as dentate region. Females with brood chamber on chaetigers 6 and 7, formed by wing-like protrusions of the integument of these chaetigers, boundaries of these chaetigers still visible (Fig. 12 A, C). Fixed specimens usually without colour and translucent, only anterior peristomial ring sometimes slightly pigmented. Pygidium dorsoventrally flattened, posterior margin oval or tapered (in paratypes) (Fig. 12 C). Anterior chaetigers darkly pigmented, blood greenish.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981870FFDD51B6F97B5CDAFC30.taxon	discussion	Remarks. We examined five incomplete paratypes, three specimens (one slightly broken) without radiolar crown, one specimen with remnant of a radiolar crown and one anterior end with radiolar crown, from the polychaete collection of the Smithsonian National Museum of Natural History. However, these specimens were not in good condition. They were dark brown in colour (Fig. 12 A – C). This indicates that they may have dried out in the past. One incomplete specimen has a radiolar crown, the chaetae of all specimens are mostly broken off. It is not certain whether these relatively small individuals are actually juveniles or whether they have shrunk due to drying out.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981870FFDD51B6F97B5CDAFC30.taxon	materials_examined	We have also made attempts to examine the holotype of this species, which is believed to be in the collection of the Zoological Museum in Kiel, Germany. However, these specimens were not found there. The presence of a brood chamber in females was not mentioned in the original description. But the wing-like protrusions on chaetigers 6 and 7 were clearly visible in one paratype (see Fig. 12 A, C). Due to the relatively poor state of conservation of paratypes, it is not possible to say with certainty whether transitional chaetae or transitional uncini are present in females. They were not mentioned in the original description. However, transitional uncini or transitional chaetae have often been overlooked in other species in the past (see Atkinson et al. 2020 and Bick et al. 2024, for example). The radiolar crown of juveniles has slightly fewer branches on the middle and ventral radioles. Median radioles have 2 and ventral radioles 3 branches (Banse 1956). Geographic distribution. Known only from the type locality, south Brazilian coast between Santos and Curitiba.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981870FFDD51B6F97B5CDAFC30.taxon	biology_ecology	Biology. Eggs were found in chaetiger 4 in females. Ecology. Manayunkia brasiliensis lives on mud in coastal mangrove habitat. Hutchings et al. (1981) suggested that this species may be exposed to hyper-marine salinity in the interstitial water at low tide.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981872FFD151B6FB9A5AF1FDE0.taxon	description	(Figures 13 – 14)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981872FFD151B6FB9A5AF1FDE0.taxon	materials_examined	Material examined. Russia, Caspian Sea: 43 ° 57.733 ’ N, 48 ° 37.840 ’ E, depth 28.7 m, coll. 12.10.2018, 23 specimens (ZMMU WS 19181 (12 specimens) and ZSRO-P 2695 (11 specimens )), 43 ° 57.733 ’ N, 48 ° 840 ’ E, depth 28.7 m, coll. 12.10.2018, 35 specimens (ZMMU WS 19182 (17 specimens) and ZSRO-P 2696 (18 specimens )), 43 ° 57.733 ’ N, 48 ° 18.100 ’ E, depth 25.7 m, coll. 10.10.2018, 14 specimens (ZMMU WS 19183 (9 specimens) and ZSRO-P 262697 (5 specimens )).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981872FFD151B6FB9A5AF1FDE0.taxon	description	Description. Total length of specimens, including radiolar crown, between 1.8 and 4.2 mm; width between 0.15 mm and 0.22 mm; length of radiolar crown between 0.22 mm and 0.40 mm; ratio between length of radiolar crown and body length, without radiolar crown, between 0.1 and 0.2; body cylindrical, slender, slightly tapering posteriorly (Fig. 13 A, D). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; surface of radioles and ventral filamentous appendages wrinkled (Fig. 13 A, B); first dorsal radioles branch off from the branchial lobe, median and ventral radioles arise from a common base (Fig. 14 B – E); ventral and median radioles asymmetrical branched or pectinated, dorsal radioles unbranched; ventral radioles with 5 – 6 branches, median radioles with 2 – 3 branches (Fig. 14 B – D); no morphological differences in the structure of the branches, except ventral filamentous appendages (Fig. 14 B, C); ventral filamentous appendages and branches of radioles end at about same height (Fig. 13 B); branches of radioles and vascularized ventral filamentous appendages rectangular to square in cross-section, extension about 20 – 28 x 24 – 40 µm and 32 – 40 x 38 – 56 µm, respectively (Fig. 14 B); vascularized ventral filamentous appendages with blood vessel (Fig. 14 B – E), connecting to corresponding dorsally located branchial heart (Fig. 14 F); epidermis of radioles and vascularized ventral filamentous appendages medially with ciliated and laterally with non-ciliated epithelial cells; ciliated cells constitute a shallow food groove (Fig. 14 B, C); center of branches of radioles occupied by a large cavity bordered by a narrow band of cells; radioles with cylindrical cells adorally (Fig. 14 B, C); dorsal lips as triangular lobes, rounded at upper margin, with ciliated epithelium all around (Fig. 14 D, E); about 30 – 40 µm long; dorsal lips connect dorsal radioles with vascularized ventral filamentous appendages. Peristomium slightly longer than first chaetiger, about as long as chaetiger 2, with anterior and posterior rings; anterior peristomial ring distinctly shorter than posterior ring (Fig. 13 A, B); anterior margin developed as low membranous collar ventrally, narrowly separated mid-dorsally (Figs 13 B, 14 A, F); ciliated band ventrally on posterior margin of anterior peristomial ring (Fig. 13 B); border between anterior and posterior peristomial rings clearly visible all around (Fig. 13 A, B); one pair of rounded black peristomial eyes present. Faecal groove dorsally deeply sunken in peristomial region (Fig. 14 F), becoming considerably lower on first and following chaetigers; faecal groove shifts from dorsal to ventral mid-line at border between thorax and abdomen (Fig. 13 D). Metanephridia in peristomium and chaetigers 1 and 2. First thoracic chaetiger shorter than peristomium and second chaetiger; chaetigers 2 – 7 successively longer; chaetiger 8 shorter than chaetiger 7 (Fig. 13 A, B); first 3 thoracic chaetigers wider than long, chaetiger 4 – 8 distinctly longer than wide (Fig. 13 A); first abdominal chaetiger long, about twice as long as second one; abdominal chaetiger 3 slightly shorter, about as long as pygidium; pygidium tapered (Fig. 13 A, D); pygidial eyes absent; borders between anterior thoracic and abdominal chaetigers clearly visible, but difficult or impossible to identify on chaetigers in females with brood chamber, i. e., particularly between chaetigers 6 and 7 (Fig. 13 A, C). First chaetiger with about 2 – 4 short and 3 – 5 elongate, narrowly hooded notochaetae, neuropodial uncini absent; notopodia of chaetigers 2 – 5 superiorly with 3 – 5 (rarely 6) elongate, narrowly hooded and inferiorly with 2 – 4 pseudo-spatulate chaetae (Fig. 13 E, F); notopodia of chaetigers 6 – 8 superiorly with 3 – 5 elongate, narrowly hooded and 2 – 4 short, narrowly hooded chaetae; neuropodia of chaetigers 2 – 5 (female) or 2 – 8 (male) with 2 – 4 (rarely 5) uncini with main fang, apical with about 4 – 6 rows of progressively smaller teeth (Fig. 13 G); females with 3 – 8 transitional uncini on chaetigers 6 – 8, different from thoracic uncini on chaetigers 2 – 5; transitional uncini longer than regular thoracic uncini, without main fang, with a multitude of rows of small, equal-sized teeth (Fig. 13 I); abdominal neuropodia with 2 – 3 elongate, and 1 – 2 short, narrowly hooded chaetae (Fig. 13 J); abdominal notopodia with 12 – 17 uncini on chaetiger 9, 8 – 15 on chaetiger 10, and 7 – 12 on chaetiger 11, respectively; uncini with about 6 rows of equal-sized teeth, about 4 – 6 teeth per row (Fig. 13 K); manubrium about 2 – 4 times as long as dentate region. Females with brood chamber on chaetigers 6 and 7, formed by wing-like protrusions of the integument of these chaetigers (Fig. 13 A, C); boundaries of these chaetigers barely visible here (Fig. 13 A). Fixed specimens usually without colour and translucent, only anterior peristomial ring sometimes slightly pigmented. Tubes, significantly longer than worms they inhabit it, consist of mucus and fine sediment particles (Fig. 13 H).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981872FFD151B6FB9A5AF1FDE0.taxon	discussion	Remarks. The brackish water species M. caspica most closely resembles the freshwater species M. danubialis Băcescu, 1948 but there are also small differences. In M. caspica, thoracic chaetigers become continuously longer from chaetiger 2 to chaetiger 7, whereas in M. danubialis chaetiger 5 is shorter than chaetigers 4 and 6. Manayunkia caspica has 2 – 5 (rarely 6) thoracic uncini, whereas M. danubialis has 6 – 8 (rarely 4) uncini. In M. danubialis, the thoracic uncini are sometimes arranged in a slightly offset double row. The thoracic and abdominal uncini differ also slightly. In M. caspica there are about 4 – 6 rows of increasingly smaller teeth above the main fang in the thoracic uncini, whereas in M. danubialis there are a maximum of 4 rows. The number of teeth per row is also somewhat lower in the freshwater species. The abdominal uncini in M. caspica have a maximum of 6 rows of teeth, in M. danubialis there are 6 – 8 rows. Furthermore, the transitional uncini of M. caspica have considerably more apical teeth than those of M. danubialis. The distribution area and habitat are also useful for distinguishing both Manayunkia species. Manayunkia caspica has been described on silty bottoms in the Caspian Sea at depths between 17 m and 64 m and salinities between 1.3 and 13.2 psu (Annenkova 1929 a, b). Manayunkia danubialis inhabit freshwater habitats, does not tolerate large fluctuations in salinity, prefer oxygen-rich and rocky habitats at shallow depths (Popescu-Marinescu 2008). The genetic distance between M. caspica and M. danubialis, based on the 18 S rDNA sequences, including gaps is 0.110 and without gaps 0.058. For comparison, the intraspecific genetic distance in M. aestuarina, including gaps, is 0.035. This leads to the conclusion that M. danubialis and M. caspica are two closely related but different species (see Fig. 24). There is a slight difference in the number of thoracic and abdominal uncini between smaller and larger individuals. Smaller individuals have fewer uncini in general. The presence of transitional uncini in mature females was also found in several other Manayunkia species (see Remarks for other species). The presence of a brood chamber in females has already been described previously (Bick et al. 2024).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981872FFD151B6FB9A5AF1FDE0.taxon	distribution	Geographic distribution. So far only known from the Caspian Sea. Records outside the Caspian Sea in southeast European rivers are questionable.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981872FFD151B6FB9A5AF1FDE0.taxon	biology_ecology	Biology. In the material we received from October 2018, there were females with eggs in chaetiger 4, deposited eggs in tubes (Fig. 13 H) and juvenile specimens with a length of slightly more than 1 mm. The eggs had a size of about 200 – 300 µm x 70 – 96 µm. It is therefore not possible to make a reliable statement about the reproduction period of this species. Ecology. This species was first found on silty bottoms from depths between 17 and 64 m and salinities between about 1.3 to 13.2 psu (Annenkova 1929 a, b).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187EFFD051B6FDEA5B85F824.taxon	description	(Figures 15 – 16)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187EFFD051B6FDEA5B85F824.taxon	materials_examined	Material examined. Austria, Danube: Hainburg, 48 ° 09.37 ’ N, 16 ° 59.39 ’ E, coll. 15.02.2022, 1 specimen (ZSROP 2671), Oberloiben, 48 ° 23.20 ’ N, 15 ° 31.22 ’ E, coll. 15.02.2022, 5 specimens (ZSRO-P 2672), Jochenstein, 48 ° 31.16 ’ N, 13 ° 42.06 ’ E, coll. 09.02.2022, 1 specimen (ZSRO-P 2673), Nussdorf, 48 ° 15.39 ’ N, 16 ° 22.12 ’ E, coll. 15.02.2022, 7 specimens (EMZ Rostock 9511), Enghagen, 48 ° 14.25 ’ N, 14 ° 30.35 ’ E, coll. 15.02.2022, 3 specimens (NHMW-ZOO-EV- 21535).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187EFFD051B6FDEA5B85F824.taxon	description	Description. Total length of specimens, including radiolar crown, between 2.2 and 3.8 mm; width between 0.15 mm and 0.26 mm; length of radiolar crown between 0.21 mm and 0.38 mm (exceptionally 0.53 mm) (Fig. 15 A – C); ratio between length of radiolar crown and body length, without radiolar crown, between 0.1 and 0.2; body cylindrical, slender, slightly tapering posteriorly (Fig. 15 A – D). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; surface of radioles and ventral filamentous appendages wrinkled (Fig. 15 A – C); ventral filamentous appendages and all branches of radioles end at about same height (Fig. 15 B, C); first dorsal radioles branch off from the branchial lobe, median and ventral radioles arise from a common base ventral and median radioles asymmetrical branched or pectinated, dorsal radioles unbranched; ventral radioles with 5, median radioles with 4 branches (Fig. 16 B – D); no morphological differences in the structure of the branches, except ventral filamentous appendages (Fig. 16 B, C); branches of radioles and vascularized ventral filamentous appendages rectangular to square in cross-section, extension about 16 – 30 x 24 – 32 µm and 35 – 40 x 43 – 56 µm, respectively (Fig. 16 B); vascularized ventral filamentous appendages with blood vessel, connecting to corresponding dorsally located branchial heart (Fig. 16 B – F); epidermis of radioles and vascularized ventral filamentous appendages adorally with ciliated and aborally with non-ciliated epithelial cells; ciliated cells constitute a shallow food groove of radioles (Fig. 16 B, C); center of branches of radioles occupied by a large cavity bordered by a narrow band of cells; radioles with cylindrical cells aborally Fig. 16 B, C); dorsal lips as triangular lobes, rounded at the upper margin, with ciliated epithelium all around (Fig. 16 C – E), about 20 – 30 µm long; dorsal lips connect dorsal radioles with vascularized ventral filamentous appendages. Peristomium slightly longer than first chaetiger, about as long as chaetiger 2, with anterior and posterior rings; anterior peristomial ring distinctly shorter than posterior one (Fig. 15 B, C); anterior margin of anterior peristomial ring developed as low membranous collar ventrally, narrowly separated mid-dorsally (Fig. 15 A – C); ciliated band present ventrally on posterior margin of anterior peristomial ring (Fig. 15 C); border between anterior and posterior peristomial rings clearly visible (Fig. 15 B); one pair of rounded black peristomial eyes. Faecal groove dorsally deeply sunken in peristomial region, considerably lower on first and following chaetigers (Fig. 15 A – B); shifting from dorsal midline to ventral midline at border between thorax and abdomen. Metanephridia located in peristomium and first 2 chaetigers. First chaetiger slightly shorter than peristomium and second chaetiger, chaetigers 2 to 4 successively longer, chaetiger 5 slightly shorter than chaetiger 4, chaetigers 6 and especially 7 significantly longer, chaetiger 8 shorter again; first 5 thoracic chaetigers wider than long, last 3 thoracic chaetigers distinctly longer than wide (Fig. 15 A, B); borders between thoracic chaetigers usually clearly visible, except between last 3 thoracic chaetigers, especially in females with brood chamber (Fig. 15 A); abdominal chaetigers short; abdomen, including pygidium, in total about as long as chaetiger 8 (Fig. 15 A, D); pygidium about same length as chaetiger 10, terminating as rounded lobe (Fig. 15 D); pygidial eyes absent. First chaetiger with 2 – 3 short, and 3 – 5 elongate, narrowly hooded notochaetae, neuropodial uncini absent (Fig. 15 E); notopodia of chaetigers 2 – 5 superiorly with 4 – 6 elongate, narrowly hooded and inferiorly with 2 – 4 pseudo-spatulate chaetae (Fig. 15 F); notopodia of chaetigers 6 – 8 superiorly with 4 – 6 elongate, narrowly hooded and 3 – 4 short, narrowly hooded chaetae (Fig. 15 G); neuropodia of chaetigers 2 – 5 (female) or 2 – 8 (male) with 6 – 8 (rarely 4) uncini with main fang and towards apical with about 4 rows of progressively smaller teeth (Fig. 15 H); sometimes uncini in a slightly offset double row; females with 3 – 5 transitional uncini on chaetigers 6 – 8, different from thoracic uncini on chaetiges 2 – 5, slightly longer than regular uncini, without main fang but with a multitude of rows of small, equal-sized teeth (Fig. 15 I); abdominal neuropodia with 3 – 5 elongate, and 2 – 4 short, narrowly hooded chaetae (Fig. 15 J); abdominal notopodia with 13 – 18 uncini on chaetiger 9, 8 – 12 on chaetiger 10, and 5 – 12 on chaetiger 11; abdominal uncini with about 6 – 8 rows of equal-sized teeth, about 5 – 6 teeth per row (Fig. 15 K); manubrium about three to four times as long as dentate region. Mature females with brood chamber on chaetigers 6 – 8, formed by wing-like protrusions of the integument, segment boundaries barely visible here (Fig. 15 A). Fixed specimens translucent, however radiolar crown, anterior intestinal region and nephridia are brownish in colour.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187EFFD051B6FDEA5B85F824.taxon	discussion	Remarks. In the redescription of M. danubialis by Bick et al. (2024), the year of description by Băcescu, was given as 1944. This information is corrected here. It has been brought to our notice that the correct date of the original description is 1948. In his 1944 paper, Băcescu, only mentioned the presence of a subspecies of M. caspica in the Danube, without mentioning a name and without any description. It was not until 1948 that the name of the subspecies M. caspica danubialis was given by Băcescu and a very brief description was added as a footnote to the name. It is also irritating that the captions of the two plates have been interchanged in this paper and the subspecies is referred to here as M. caspica fluviatilis. This name was also used by Marinov (1977) in his synonym list of M. caspica. Manayunkia danubialis most closely resembles M. caspica. Morphological differences and genetic distances between both species are described in the Remarks on M. caspica. These differences are not great. A comparison of specimens of comparable size also shows that the number of thoracic uncini is greater in M. danubialis. Individuals longer than 3 mm have on average 6 – 8 thoracic uncini, while those smaller than 2.5 mm have only 2 – 4. In contrast, specimens of M. caspica that are longer than 3 mm have on average only 3 – 4 thoracic uncini and those that are smaller than 2.5 mm have also 2 – 4 uncini.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187EFFD051B6FDEA5B85F824.taxon	distribution	Geographic distribution. So far only known from the Danube (Romania to Austria, Germany?). A further invasion of the upper Danube and its tributaries is likely. This means that migration beyond the Danube into other river systems is likely to continue.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187EFFD051B6FDEA5B85F824.taxon	biology_ecology	Biology. Manayunkia danubialis reaches abundances of thousands of specimens per one square meter in suitable habitats in the Romanian Danube. Females have oocytes in chaetiger 5 and males have sperm in chaetigers 6 – 8. Eggs are about 0.14 – 0.23 mm in diameter. Chaetigers 6 – 8 in females are elongated and form a brood chamber. The peak of reproduction is in May. More than 40 per cent of specimens are than egg-carrying females. Another peak of egg laying is assumed to occur autumn (September – November). The egg-laying and development of larvae takes place in the maternal tube. Three to 15 specimens (mean number 8) in various stages of development were found simultaneously in the tubes of the females (Popescu-Marinescu 2008). In specimens we examined, two early developmental stages of 200 µm length were found in a maternal tube in February, indicating an onset of the reproduction in early spring. Ecology. Manayunkia danubialis is a species that does not tolerate large salinity fluctuations, prefer oxygen-rich and stony habitats mainly in the riparian area (Popescu-Marinescu 2008).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187AFFEB51B6FF175D36F8AB.taxon	description	(Figures 17 – 18)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187AFFEB51B6FF175D36F8AB.taxon	materials_examined	Material examined. Russia, Lake Baikal: 53 ° 07.173 ’ N, 109 ° 04.289 ’ E, depth 35 – 40 m, coll. 24.07.2006, 15 specimens (ZSRO-P 1942).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187AFFEB51B6FF175D36F8AB.taxon	description	Description (based on the description of Nusbaum (1901), Dybowski (1929), Sitnikova et al. (1997) and own observations). Total length of specimens, including radiolar crown, between 9 and 16 mm (on average about 10 mm long); width about 0.4 – 1.6 mm; (on average about 0.9 mm); length of radiolar crown between 0.5 and 1.7 mm (on average 1.2 mm); ratio between length of radiolar crown and body length, without radiolar crown, between 0.06 and 0.2; body slender, posteriorly tapered (Fig. 17 B). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; surface of radioles and ventral filamentous appendages wrinkled (Fig. 17 A); dorsal radioles unbranched, median and ventral radioles with large number of branches, usually 2 (or more?) branches arise from a common base, so that the branches appear to be arranged in two rows; radiolar crown with 72 – 104 branches in total (on average about 80); ventral filamentous appendages and almost all branches of the radioles end at about the same height, dorsal radioles sometimes slightly shorter (Fig. 17 A). Peristomium distinctly longer than the first chaetiger, with anterior and posterior rings; anterior margin of anterior peristomial ring developed as low membranous collar ventrally, indented laterally, and narrowly separated mid-dorsally; border between anterior and posterior peristomial rings clearly visible (Fig. 17 A); one pair of black peristomial eyes present. Chaetigers 1 – 5 or 6 successively longer, chaetigers 7 and 8 successively shorter; abdomen about as long as chaetiger 3 or 4; margins of chaetigers 6 – 8 often not clearly visible in adult specimens. Thoracic notopodia with rounded or triangular prechaetal lobes (Figs 17 C, E, F, 18 B); first chaetiger inferiorly with 5 – 7 short, and superiorly with 6 – 10 elongate, narrowly hooded notochaetae, neuropodial uncini absent; notopodia of chaetigers 2 – 8 posteriorly with about 12 – 16 elongate, narrowly hooded chaetae, about 1 – 1.2 mm long, and anteriorly with about 10 – 12 short, narrowly hooded chaetae (Fig. 17 C, E, F); neuropodia of chaetigers 2 – 8 (males) or 2 – 5 (females) with 5 – 12 (on average 8) uncini, about 0.36 mm long, with main fang and apical with about 5 – 6 rows of progressively smaller teeth (Fig. 17 D); neuropodia of females with 5 – 8 transitional chaetae on chaetigers 6 – 8 (Fig. 17 F); abdominal neuropodia with 5 – 8 narrowly hooded chaetae; abdominal notopodia with about 20 – 42 uncini, about 0.15 mm long, dentate region with about 5 – 6 rows of equal-sized teeth, about 4 – 6 teeth per row (Fig. 17 G, H); dentate region about 10 – 14 µm long. Brood chamber of females formed by bulge-like protrusions ventrally on chaetigers 6 and 8 (Fig. 18 A, B). Pygidium triangular, pointed, but not elongated (Figs 17 B, 18 A). Anterior chaetigers with little pigment, blood greenish.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187AFFEB51B6FF175D36F8AB.taxon	discussion	Remarks. In addition to the very short original description of M. godlewskii by Nusbaum (1901), there are detailed descriptions by Zenkevitsch (1925) and Dybowski (1929). However, these descriptions can only be used with some reservations. As Zenkevitsch (1925) synonymised M. godlewskii with M. baicalensis, the characters of both species are therefore obviously mixed. Dybowski (1929) also did not separate the two species. It is possible that these descriptions also include characters of M. zenkewitschii. This species was first described by Sitnikova et al. (1997). However, Sitnikova et al. (1997) were also able to show that M. godlewskii and M. baicalensis differ morphologically. Manayunkia godlewskii is much less pigmented than M. baicalensis, it is larger and has significantly more branches of the radiolar crown, and this species colonises muddy bottoms, in contrast to M. baicalensis, which prefers sandy substrates. Pudovkina et al. (2016) confirmed the separation of both species by using genetic methods. With a length of up to 16 mm, M. godlewskii is by far the largest species of the genus. Only M. baicalensis, with a length of up to 8 mm, is also significantly larger than the other Manayunkia species. Manayunkia godlewskii is the only species of Manayunkia in which the thoracic notopodia have prechaetal lobes. It is possible that the significantly greater length of this species compared to the related species requires such a structure. Similar lobes are found, for example, in species of Sabellidae (cf. Bick & Randel 2012). The number of branches of the median and ventral radioles is comparatively high, at least in comparison to most of the smaller species. This is explained by the fact that immediately after branching, the branches divide further, so that 2 or even more branches branch off from a common base. Zenkevitsch (1925) and Sitnikova et al. (1997) then concluded that the branches of the tentacle crown are arranged in two rows. Manayunkia godlewskii is characterised in particular by a triangular but not elongated pygidium. The pygidium of the other two species from Lake Baikal is either elongated and pointed or oval. In addition, the pigment is almost completely absent or at most present on first two chaetigers. In M. baicalensis the first 6 chaetigers are distinctly pigmented, and in M. zenkewitschii all chaetigers are pigmented. There is a sexual dimorphism in this species. Mature females have transitional chaetae on neuropodia of chaetigers 6 – 8 instead of regular thoracic uncini. A brood chamber, which is formed by bulge-like protrusions ventrally on chaetigers 6 and 8, is also present in females. These characters are also found in M. baicalensis (Zenkevitsch 1925) and M. zenkewitschii (Sitnikova et al. 1997). Zenkevitsch (1925) also stated that the number of thoracic chaetae and thoracic and abdominal uncini differ between males and females. Males have more chaetae and uncini than females. We did not have enough material to confirm this. However, the number of thoracic and abdominal uncini is significantly lower in smaller individuals. Specimens with a length of about 2 mm have only about 2 – 4 thoracic uncini, and 11 – 15 abdominal uncini on chaetiger 9, 8 - – 12 on chaetiger 10 and 6 – 10 on chaetiger 11.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187AFFEB51B6FF175D36F8AB.taxon	distribution	Geographic distribution. Known from Russia, Lake Baikal and probably from Lake Baunt, which is located about 200 km east of Lake Baikal.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D88798187AFFEB51B6FF175D36F8AB.taxon	biology_ecology	Biology. The reproduction period is in September and October. However, some females with embryos in the tube have also been found in November and December. In some years, reproduction has also taken place at the end of March / beginning of April. The eggs are between 350 and 425 µm long and 270 and 300 µm wide. The maximum number of eggs and embryos in the tube was 48 (Sitnikova et al. 1997). Ecology. Manayunkia godlewskii occurs throughout Lake Baikal. It inhabits mainly muddy bottoms with detritus, muddy sand, but also pebbles and rocky areas. The depth distribution ranges from about 3 to 80 m.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981845FFE851B6FF175B05FDE1.taxon	description	(Figure 19)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981845FFE851B6FF175B05FDE1.taxon	materials_examined	Material examined. Paratypes: South Pacific, Bismarck Sea, Papua New Guinea, Madang, near Riwo Village, 05 ° 09 ’ 30 ’’ S, 145 ° 48 ’ 00 ’’ E, depth 1 m, coll. 30.08.1993, 7 specimens (USNM 172109).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981845FFE851B6FF175B05FDE1.taxon	description	Description (based on the description of Rouse (1996) and own observations). Total length of specimens 1.7 mm; width about 0.08 – 0.1 mm; length of radiolar crown about 0.15 – 0.21 mm; ratio between length of radiolar crown and body length, without radiolar crown, between 0.14 – 0.15; body slender, posteriorly slightly tapered (Fig. 19 A, B, D). Radiolar crown composed of three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; dorsal radioles unbranched, median and ventral radioles with a maximum of 3 branches each; vascularized ventral filamentous appendages same length and width as branches of the radioles; dorsal lips tapered distally, about 60 – 70 µm long (Fig. 19 C). Peristomium with anterior and posterior rings, anterior ring about same length as posterior ring; anterior margin of anterior peristomial ring developed as a low membranous collar ventrally, and narrowly separated mid-dorsally; border between anterior and posterior rings clearly visible (Fig. 19 C); one pair of black rounded peristomial eyes. Metanephridia in peristomium and first 2 chaetigers. First chaetiger shorter than peristomium and second chaetiger (Fig. 19 A, C), chaetigers 2 – 7 successively longer, chaetiger 6 and 7 significantly longer than chaetiger 5, chaetiger 8 shorter than chaetiger 7; first 5 thoracic chaetigers wider than long, last 3 thoracic chaetigers distinctly longer than wide (Fig 19 A); borders between thoracic chaetigers clearly visible; abdominal chaetigers short, borders between abdominal chaetigers indistinct; abdomen, including pygidium, distinctly shorter than chaetiger 8 (Fig. 19 D); pygidium about same length as chaetiger 11, terminating as rounded lobe (Fig. 19 D); pygidial eyes absent. Thoracic notopodia superiorly with 2 – 3 elongate, narrowly hooded chaetae on chaetigers 1 – 8, inferiorly with 2 – 3 pseudo-spatulate chaetae on chaetigers 2 – 5 (Fig. 19 E), and 1 – 2 short, narrowly hooded chaetae on chaetigers 1 and 6 – 8; neuropodia of chaetigers 2 – 8 with 2 – 4 uncini, with main fang and towards apical with about 4 – 5 rows of progressively smaller teeth; abdominal neuropodia with 1 – 2 elongate, narrowly hooded chaetae; abdominal notopodia with about 8 – 10 uncini; uncini with about 6 rows of equal-sized teeth, about 5 – 6 teeth per row. Pygidium posteriorly tapered (Fig. 19 B, D). Nephridia but particularly dorsal lips darkly pigmented (Fig. 19 B, C), radioles with orange pigmentation in living specimens. Preserved specimens colourless, with brownish pigmentation on radioles and gut in chaetigers 2 – 5 (Fig. 19 A – C).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981845FFE851B6FF175B05FDE1.taxon	discussion	Remarks. With a length of just over 1.5 mm, M. mizu is the smallest Manayunkia species and the only marine species apart from M. brasiliensis. In the original description, it was stated that in preserved specimens, the gut in chaetigers 2 – 4 was green pigmented (certainly because of the food consumed). In the individuals we examined, however, the gut in chaetigers 2 – 5 was brownish. The very darkly pigmented dorsal lips were particularly conspicuous in the specimens we examined. We saw neither transitional chaetae nor transitional uncini in the paratypes available to us. We also could not find a brood chamber.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981845FFE851B6FF175B05FDE1.taxon	distribution	Geographic distribution. Known only from the type locality, Papua New Guinea, Madang province.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981845FFE851B6FF175B05FDE1.taxon	biology_ecology	Biology. In females, oocytes develop in chaetigers 4 and 5, while spermatogenesis in males takes place in chaetigers 6 – 8. Larval development takes place in the tube of females (Rouse 1996). Ecology. Between green algae (Halimeda spec.) and seagrass in mangrove habitat. Tubes are composed of fine calcareous sediment, mangrove detritus, and mucus (Rouse 1996).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981847FFEF51B6FDEA5962FA80.taxon	description	(Figure 20)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981847FFEF51B6FDEA5962FA80.taxon	materials_examined	Material examined. USA, California, Klamath River, 41 ° 51 ' 45.91 " N, 122 ° 33 ' 53.96 " W, coll. 24.07.2006, 10 specimens (ZSRO-P 2698).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981847FFEF51B6FDEA5962FA80.taxon	description	Description (based on the description of Atkinson et al. (2020) and own observations). Total length of specimens about 1.8 – 2.4 mm (unfixed 3.0 – 4.5 mm); width between 0.2 – 0.3 mm; length of radiolar crown about 0.2 – 0.3 mm; ratio between length of radiolar crown and body length, without radiolar crown, about 0.12 – 0.18; body cylindrical, posteriorly tapered (Fig. 20 A, H). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; surface of radioles and ventral filamentous appendages wrinkled; dorsal radioles unbranched, median and ventral radioles with about 6 branches each; branches of radioles on the inner side with short median and long latero-frontal cilia (Fig. 20 B); vascularized ventral filamentous appendages almost as long as radioles or about twothird of length of radioles, about as wide as radioles; no morphological differences in the structure of the branches of the radiolar crown, except ventral filamentous appendages. Peristomium with anterior and posterior rings, anterior ring shorter than posterior ring; anterior margin of anterior peristomial ring developed as a low membranous collar ventrally, and narrowly separated mid-dorsally; border between anterior and posterior peristomial rings visible (Fig. 20 C); one pair of black rounded peristomial eyes. Metanephridia located in peristomium and first 2 chaetigers. First chaetiger usually significantly shorter than peristomium and second chaetiger (Fig. 20 C), chaetigers 2 – 6 successively longer, chaetiger 6 significantly longer than chaetiger 5, chaetigers 7 and 8 succesively shorter; first 5 thoracic chaetigers wider than long, last 3 thoracic chaetigers distinctly longer than wide (Fig. 20 A); borders between thoracic chaetigers clearly visible; abdominal chaetigers short, borders between abdominal chaetigers indistinct; abdomen, including pygidium, in total about as long as chaetiger 7 (Fig. 20 A, H); pygidium about same length as chaetiger 10, terminating as rounded lobe (Fig. 20 A, H); pygidial eyes absent. Thoracic notopodia superiorly with 5 – 7 elongate, narrowly hooded chaetae on chaetigers 1 – 5, 4 – 5 on chaetigers 6 – 8, inferiorly with 3 – 6 short, narrowly hooded chaetae (Fig. 20 D – G); neuropodia of males with 4 – 6 (rarely 7) uncini on chaetigers 2 – 8, with main fang and apical with about 4 – 6 rows of progressively smaller teeth (Fig 20 I – K); neuropodia of females with same number and shape of uncini on chaetigers 2 – 5, followed by 3 – 6 transitional chaetae on chaetigers 6 – 8; sometimes thoracic uncini in a slightly offset double row; abdominal neuropodia with elongate, narrowly hooded chaetae, decreasing posteriorly from 4 – 6 to 1 – 2 per fascicle (Fig. 20 H); abdominal notopodia with about 20 – 22 uncini on chaetiger 9, 14 – 18 on chaetiger 10 and 8 – 12 on chaetiger 11; abdominal uncini with about 4 – 6 rows of equal-sized teeth; manubrium about five times longer than dentate region. Abdomen dorso-ventrally flattened, posteriorly tapered or rounded (Fig. 20 H). Body wall of living specimens translucent grey with minor brown pigmentation on radiolar crown, peristomium and pygidium; one ventral radiole with 4 – 5 yellow-white spots in life; fixed specimens colourless, transparent, only anterior margin of peristomium, metanephridia and sometimes also radioles slightly brownish; females with pigmented spermathecae in the base of radiolar crown.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981847FFEF51B6FDEA5962FA80.taxon	discussion	Remarks. Manayunkia occidentalis most closely resembles M. speciosa. Females of both species have transitional chaetae on chaetigers 6 – 8, but bulge-like protrusions on chaetigers 6 and 8 are absent. The occurrence of a brood chamber was not yet described. We also found no brood chamber when we examined specimens from Klamath River. One specimen had a longitudinal furrow on chaetigers 6 to 8, but this was located dorsally in the area of the faecal groove (Fig. 20 A). It is therefore not very likely that this furrow actually represents a brood chamber. However, it cannot be completely excluded. Transitional chaetae are also found in the three species from Lake Baikal, but these species have bulge-like protrusions on chaetigers 6 and 8. Manayunkia occidentalis has significantly fewer branches in the radiolar crown than M. speciosa, about 22 – 26 vs. about 34 – 42. In addition, M. occidentalis appears to be smaller than M. speciosa (fixed specimens: about 2.5 mm vs. about 4.9 mm), but still has more thoracic uncini (4 – 7 vs. 2 – 5). This is remarkable in that smaller species usually have fewer uncini. Small (immature) females have only one transitional chaeta on each of the chaetigers 6 – 8. Apart from these transitional chaetae, there were no regular thoracic uncini on the neuropodia of these chaetigers.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981847FFEF51B6FDEA5962FA80.taxon	distribution	Geographic distribution. Northwestern United States: California, Klamath and Willamette Rivers.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981847FFEF51B6FDEA5962FA80.taxon	biology_ecology	Biology. Manayunkia occidentalis was overlooked for a long time and confused with M. speciosa. However, only Manayunkia occidentalis is an obligate invertebrate host of the myxozoan parasites Ceratonova shasta and Parvicapsula minibicornis, which cause ceratomyxosis in salmon and trout in North America (Bartholomew et al. 2006, Alexander et al. 2014), but not M. speciosa, which occurs in the Great Lakes region and in the eastern river systems of the USA. This is a very good example of the need for thorough taxonomic analyses. Infection with C. shasta in adult Chinook salmon causes mortality through intestinal perforations and co-occurring bacterial infections (Bartholomew 1998). Approximately 70 – 100 % of juvenile Chinook salmon are infected by the parasites during early summer when these fish migrate to the ocean. They can cause mortality rates of approximately 40 % in Oncorhynchus spp. (Schloesser et al. 2016). Parvicapsula minibicornis is found in the kidneys of juvenile Chinook salmon, but the effect of the infection is not yet clear because it is often present with C. shasta. Females have oocytes in chaetigers 4 – 5, and males have sperm and spermatids in chaetigers 6 – 8. Larval development takes place in the tube of females. Adult worms with overt parasite infections often lacked gametes. The greatest number of larvae that has been found simultaneously in the tube of a female is 35; under laboratory conditions, a total of 36 larvae were recorded over the course of a season (Wilson et al. 2010). Mechanical disturbance by large benthic species and lack of oxygen in the sediment cause the specimens to quickly leave their tube or withdraw deep into the tube. However, Wilson et al. (2010) observed that mature females with larvae in their tubes left the tubes less often than males or non-breeding females. Ecology. Manayunkia occidentalis was found in clusters of tubes, attached to rocks or intertwined with periphyton.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981840FFEC51B6FA4A5C7CFD08.taxon	description	(Figures 1 and 21)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981840FFEC51B6FA4A5C7CFD08.taxon	materials_examined	Material examined. USA, North Carolina, Lake Norman, 35 ° 26 ’ N, 80 ° 56 ’ W, coll. 6. or 7.10.1981, 7 specimens (USNM 68726); Western Lake Erie, coll. 1963, 137 specimens (USNM 31015).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981840FFEC51B6FA4A5C7CFD08.taxon	description	Description (based on the descriptions of Leidy (1883), Potts (1884), Pettibone (1953), Atkinson et al. (2020) and own observations). Total length of specimens about 2.5 – 4.9 mm, width about 0.25 – 0.3 mm; length of radiolar crown about 0.4 – 0.8 mm; ratio between length of radiolar crown and body length, without radiolar crown, about 0.2 – 0.3. Body cylindrical, posteriorly rounded (Figs 1.1, 21 A – C). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; dorsal radioles unbranched, median and ventral radioles with a maximum of 10 branches each in adults but lower in juveniles; vascularized ventral filamentous appendages slightly wider and longer than radioles (Figs 1.1, 21 A, B). Metanephridium in peristomium and chaetigers 1 – 2 (Fig. 1.1). Peristomium about as long as wide, with anterior and posterior rings; anterior ring distinctly shorter than posterior ring; anterior margin of anterior peristomial ring developed as low membranous collar ventrally, narrowly separated mid-dorsally; border between anterior and posterior peristomial rings indistinct; with one pair of black rounded peristomial eyes (Figs 1.1, 21 A, B). Chaetigers 1 to 5 almost same length or successively longer, chaetigers 6 and 7 longest, chaetiger 8 shorter again; first 5 thoracic chaetigers wider than long, last 3 thoracic chaetigers distinctly longer than wide; abdomen, including pygidium, as long as chaetiger 8, often separated from thorax by a widening at chaetiger 9 (Fig. 21 A, C); chaetigers 9 to 11 successively shorter; borders between thoracic chaetigers usually visible and between abdominal chaetigers indistinct; pygidium as long as chaetiger 10 (Figs 1.1, 20 A, C). Thoracic notopodia with about 4 – 6 elongate, and about 2 – 4 short, narrowly hooded chaetae, length of chaetae 100 – 250 µm (Figs 1.3, 1.4, 21 D – G); thoracic neuropodia of males with 2 – 4 (sometimes 5) uncini, neuropodia of females with same uncini on chaetigers 2 – 5, followed by transitional chaetae on chaetigers 6 – 8; thoracic uncini about 50 – 60 µm long, with main fang and apical with about 5 – 6 rows of progressively smaller teeth (Figs 1.5, 21 I); abdominal neuropodia with elongate, narrowly hooded chaetae, decreasing posteriorly from 5 – 7 to 2 – 4 per fascicle (Fig. 21 H); abdominal notopodia with about 20 – 24 (max. 30) uncini on chaetiger 9, 16 – 18 on chaetiger 10, and 12 – 14 on chaetiger 11; abdominal uncini about 20 – 30 µm long, with about 5 – 7 rows of equal-sized teeth, and about 4 – 6 teeth per row (Figs 1.6, 1.7, 21 J). Pygidium short and rounded (Figs 1.1, 21 A, C). Body wall translucent olive-green, radioles with minor brown pigmentation; base of radioles with 6 – 10 brownish pigment spots (Fig. 1.1); spots not visible when preserved.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981840FFEC51B6FA4A5C7CFD08.taxon	discussion	Remarks. Manayunkia speciosa most closely resembles M. occidentalis. For the differences between these two species, see the Remarks in M. occidentalis. Females and males differ in the presence or absence of transitional chaetae on segments 6 – 8, as already described by Atkinson et al. (2020). Leidy (1883) described and illustrated the occurrence of an expansion at the beginning of chaetiger 6 (Fig. 1.1), which he interpreted as the possible beginning of paratomy (transverse division with head formation). Zenkevitsch (1925) already referred to this structure and its possible function as a brood chamber in this species when he described a brood chamber in M. baicalensis (Nusbaum, 1901). Pettibone (1953) also described a thickened semicircular band on the ventral side of the anterior part of chaetiger 6, and mentioned Zenkevitsch's (1925) assumption that it could be part of a brood chamber. Holmquist (1973), on the other hand, found no evidence of a brood chamber in specimens from Alaska. In the material available to us from North Carolina (from October) and from Western Lake Erie (without any exact date of collection) we also did not find any indication of a brood chamber in females. The occurrence of Manayunkia speciosa has been documented from several regions of North America. However, it has been shown that the specimens found in the north-west of the United States, far from the type locality in the eastern part of the USA, belong to a different species. This species has been described as M. occidentalis (see Remarks in M. occidentalis). It would also be interesting to know whether the individuals from the southern states of the USA, e. g. North Carolina, really belong to M. speciosa and whether there is a genetic difference between these specimens and those from the north-east of the USA. It can be also assumed that the specimens found in freshwater lakes of northern Alaska, which were recorded by Holmquist (1967, 1973) and labelled as M. speciosa, must be assigned to another, undescribed species.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981840FFEC51B6FA4A5C7CFD08.taxon	distribution	Geographic distribution. Northeastern United States: Pennsylvania, New Jersey, North Carolina, Great Lakes, northern Alaska (?).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981840FFEC51B6FA4A5C7CFD08.taxon	biology_ecology	Biology. Abundances of more than 45,000 specimens per square meter have been reported for M. speciosa in the mouth of the Detroit River, western Lake Erie (Hiltunen 1965). Males have sperm and spermatids in chaetigers 6 – 8. Eggs develop in females in chaetiger 4. The oviduct opens between the 4 th and 5 th chaetiger. Eggs are oval, and have a length of 0.135 mm and a width of 0.095 mm (Meehean 1929). The eggs are laid in the tube, where they develop into young worms that leave the tube with 8 to 9 chaetigers (Fig. 1.8 – 1.13). The reproduction of this species was described by Schloesser et al. (2016). According to these authors, mature specimens were found from April to October. The sex ratio was approximately 1: 1 on average, but with a higher proportion of males (72 %) in April and a higher proportion of females in October (80 %). This means that males become sexually mature earlier than females, and females remain mature longer than males. Reproduction is continuous from May to September, but a first peak recruitment occurs between late June and mid-July and second peak in early September. But in October, females with eggs and males with sperm were still found in North Carolina (own observation). The mean number of larvae found in the tubes of females is approximately 5, and the maximum number is 20. Schloesser et al. (2016) assumed a minimum life span of approximately 10 months for this species. Mechanical disturbances or lack of oxygen result in an exit from their tubes or deep withdrawal. When they left their tubes, they often took with juveniles as well. Schloesser et al. (2016) concluded from their observations from western Lake Erie that a large proportion of individuals occur outside of their tubes most of the time during warmer months and that their tubes are not maintained in colder months. Manayunkia speciosa was long confused with M. occidentalis. However, only M. occidentalis is an obligate intermediate host for myxozoan parasites, but not M. speciosa, which has long been incorrectly described as an intermediate host (see Remarks on biology of M. occidentalis). Ecology. Tubes composed of mud or fine particles, attached partly along their length to fixed objects but the greater part free, pendant. According to Leidy (1883), most of the tubes of M. speciosa occur as single tubes, but two to five tubes connected together have been found in some cases (Fig. 1.2).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981843FFE251B6FCC25981FCC1.taxon	description	(Figure 22)	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981843FFE251B6FCC25981FCC1.taxon	materials_examined	Material examined. Russia, Lake Baikal: 55 ° 25.833 ’ N, 109 ° 12.254 ’ E, depth 11.1 – 12.5 m, coll. 27.07.2006, about 30 specimens (ZSRO-P 1941).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981843FFE251B6FCC25981FCC1.taxon	description	Description (based on the description of Sitnikova et al. (1997) and own observations). Total length of specimens, including radiolar crown, between 2.5 and 4 mm (on average about 3 mm); width about 0.4 mm; length of radiolar crown between 0.5 and 0.6 mm; ratio between length of radiolar crown and body length, without radiolar crown, between 0.1 and 0.2; body slender, posteriorly rounded (Fig. 22 A). Radiolar crown with three pairs of radioles and one pair of unbranched vascularized ventral filamentous appendages; dorsal radioles unbranched, median and ventral radioles with more than 6 branches, about 22 – 38 branches in total, rarely 40 – 42 (on average about 28); no morphological differences in the structure of the branches, except ventral filamentous appendages; ventral filamentous appendages and almost all branches of radioles end usually at about same height, dorsal radioles sometimes shorter than branches of the middle and ventral radioles. Peristomium distinctly longer than first chaetiger, with anterior and posterior rings; anterior margin of anterior peristomial ring as a low membranous collar ventrally, indented laterally, and narrowly separated mid-dorsally; border between anterior and posterior peristomial rings clearly visible; one pair of black peristomial eyes. Chaetigers 1 – 6 each successively longer, chaetigers 7 and 8 successively shorter; abdomen about as long as chaetiger 4 or 5; margins of chaetigers 6 to 8 and of abdominal chaetigers often not clearly visible in adult specimens (Fig. 22 A). First chaetiger inferiorly with 2 – 4 short, and superiorly with 4 – 6 elongate, narrowly hooded notochaetae, neuropodial uncini absent. Notopodia of chaetigers 2 – 8 superiorly with about 4 – 6 elongate, narrowly hooded chaetae, about 0.4 – 0.5 mm long, and inferiorly with about 6 – 8 short, narrowly hooded chaetae, about 0.1 – 0.2 mm long (Fig. 22 B, C); neuropodia of chaetigers 2 – 8 (male) or 2 – 5 (female) with 6 – 10 (on average 7) uncini, with main fang and apical with about 4 – 5 rows of progressively smaller teeth (Fig. 22 B, D); neuropodia of females with 3 – 4 transitional chaetae or transitional uncini on chaetigers 6 – 8 (Fig. 22 E – G); abdominal neuropodia with 2 – 4 narrowly hooded chaetae; abdominal notopodia with about 10 – 28 uncini; dentate region with about 6 – 8 rows of equal-sized teeth; dentate region about 15 – 18 µm long. Brood chamber of females formed by bulge-like protrusions ventrally on chaetigers 6 and 8. Pygidium rounded, not extended (Fig. 22 A). All chaetigers well pigmented.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981843FFE251B6FCC25981FCC1.taxon	discussion	Remarks. This is the smallest of the three Manayunkia species from Lake Baikal. Manayunkia zenkewitschii is characterized above all by an oval pygidium. The pygidium of the other two species from Lake Baikal is either elongated and pointed or triangular. In addition, in M. zenkewitschii all chaetigers are pigmented, in M. godlewskii (Nusbaum, 1901) the pigment is almost completely absent, and in M. baicalensis (Nusbaum, 1901) only the first 6 chaetigers are pigmented. There is a sexual dimorphism in this species. Mature females have transitional chaetae and transitional uncini on neuropodia of chaetigers 6 – 8 instead of regular thoracic uncini. The presence of both transitional chaetae and transitional uncini is unique among the species of Manayunkia. Usually only one type of these particular chaetae is found on chaetigers 6 to 8 in females. A brood chamber, formed by bulge-like protrusions ventrally on chaetigers 6 and 8, is also present. Chaetigers 6 to 8 are slightly elongated in mature males. Both characters are also found in M. baicalensis and M. godlewskii (see Sitnikova et al. 1997).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981843FFE251B6FCC25981FCC1.taxon	distribution	Geographic distribution. Known only from Lake Baikal, Russia.	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
03D887981843FFE251B6FCC25981FCC1.taxon	biology_ecology	Biology. The eggs deposited in the tube of the females have a length of about 220 – 290 µm and a width of 150 – 180 µm. A maximum of 18 developmental stages, eggs and embryos, can be observed simultaneously in the tubes. The main reproduction period is in June. However, females with eggs have also been found in February and March (Sitnikova et al. (1997). Ecology. The specimens of this smallest Baikal species mainly settle on stones and rocky ground, which can also be covered with sponges or algae, but also on sand with algae and on empty tubes of caddisflies (Pudovkina et al. 2016, Sitnikova et al. 1997).	en	Bick, Andreas, Bastrop, Ralf (2025): Revision of the genus Manayunkia Leidy, 1859, and establishment of two subfamilies within Fabriciidae (Annelida, Sabellida). Zootaxa 5661 (1): 1-58, DOI: 10.11646/zootaxa.5661.1.1, URL: https://doi.org/10.11646/zootaxa.5661.1.1
