Aricidea (Acmira) katzmanni, Erdoğan-Dereli & Çinar, 2020

Erdoğan-Dereli, Deniz & Çinar, Melih Ertan, 2020, The diversity of the genus Aricidea (Polychaeta: Paraonidae) from the Sea of Marmara, with descriptions of two new species and two new records for the Mediterranean fauna, Zootaxa 4844 (1), pp. 1-73 : 28-36

Aricidea (Acmira) katzmanni new species

( Figures 17–22 )

LSIDurn:lsid:zoobank.org:act: 49B63C3F-B1D0-4F17-9733-9A8712D52A04

Material examined. Holotype: ESFM-POL/2013-974 , 06 June 2013, station Y1, 40°00’27’’N, 26°13’24’’E, 10 m, mud . Paratypes: ESFM-POL/2012-291 , 27 September 2012, station K8, 40°28’03’’N, 27°42’35’’E, 7-8 m, P. oceanica , 1 specimen ; ESFM-POL/2013-977 , 06 June 2013, station Y1, 40°00’27’’N, 26°13’24’’E, 10 m, mud, 9 specimens ; ESFM-POL/2013-45 , 06 June 2013, station Y1, 40°01’08’’N, 26°13’00’’E, 50 m, mud, 1 specimen ; ESFM-POL/2013-43 , 06 June 2013, station Y2, 40°06’28’’N, 26°22’51’’E, 10 m, mud with shell fragments, 36 specimens ; ESFM-POL/2013-59 , 06 June 2013, station Y2, 40°06’59’’N, 26°22’04’’E, 50 m, muddy sand, 1 specimen ; ESFM-POL/2013-978 , 06 June 2013, station Y2, 40°06’32’’N, 26°22’31’’E, 25m, mud with pebble, 3 specimens ; ESFM-POL/2013-981 , 06 June 2013, station Y2, 40°06’59’’N, 26°22’04’’E, 50 m, muddy sand, 8 specimens ; ESFM-POL/2013-982 , 09 June 2013, station Y16, 40°18’35’’N, 27°45’46’’E, 10 m, fine sand, 11 specimens .

Additional material examined. ESFM-POL/2005-2360 , 07 October 2005, Levantine Sea , Göcek, 36º44’20’’N, 28º55’43’’E, 3 m, Zostera marina , 29 specimens ; ESFM-POL/2013-984 , 09 June 2013, station Y17, 40°39’16’’N, 27°41’14’’E, 25 m, fine sand, 19 specimens ; ESFM-POL/2013-986 , 09 June 2013, station Y17, 40°39’58’’N, 27°41’08’’E, 50 m, mud, 8 specimens ; ESFM-POL/2013-987 , 12 June 2013, station Y19, 40°58’36’’N, 27°42’29’’E, 25 m, mudy sand with Lithothamnion sp., 1 specimen ; ESFM-POL/2013-990 , 13 June 2013, station Y24, 41°03’55’’N, 28°09’12’’E, 10 m, sandy mud with shell fragments, 1 specimen ; ESFM-POL/2013-992 , 16 June 2013, station Y24, 41°03’08’’N, 28°08’44’’E, 25 m, mudy sand with Lithothamnion sp., 3 specimens ; ESFM-POL/2013-994 , 17 June 2013, station Y29, 40°32’22’’N, 28°46’59’’E, 10 m, sand with pebble, 25 specimens ; ESFM-POL/2013-995 , 14 June 2013, station Y31, 40°01’44’’N, 28°26’31’’E, 10 m, sand, 1 specimen ; ESFM-POL/2016-198 , 3 February 2016, Sea of Marmara (Bosphorus), Karaköy, 41°01’29”N, 28°58’55”E, 25 m, sandy mud with shell fragments, 1 specimen ; ESFM-POL/2016-192 , 23 August 2016, Levantine Sea , off Finike, 36°17’21”N, 30°13’18”E, 56 m, mud, 1 specimen ; ESFM-POL/2016-193 , 25 August 2016, Aegean Sea , Marmaris, 36°50’58”N, 28°16’43”E, 19 m, mud, 34 specimens ; ESFM-POL/2016 - 194,19 August 2016, Aegean Sea , Güllük, 37º14’55”N, 27º20’30”E, 37.5 m, sandy mud, 3 specimens .

Description. Holotype incomplete (some paratypes complete), 8.44 mm long (2.74–13.67 mm long in paratypes), 0.32 mm wide (0.20–0.57 mm wide in paratypes) with 86 chaetigers (30–102 chaetigers in paratypes). Color of holotype in alcohol yellowish (also in all paratypes); gamete bearing specimens having red speckles near notopodia along body ( Fig. 19I ). Body cylindrical and stout; width of prebranchial and branchial regions nearly same; segmentation narrow in branchial region; slightly thickened in postbranchial region ( Figs 17A ; 18A ; 19A ; 20A ; 21 A–B).

Prostomium subtriangular; much wider than long (ratio length / width: 0.88), anterior margin rounded ( Figs 17A ; 18 A–B; 20C); eyes absent in holotype, present in most paratypes. Crown-like ciliary band (clcb) present ( Figs 17A ; 18A ; 20B, C ; 22A ). A pair of ciliary slits (cs) located just anterior to nuchal organs, semicircular in shape ( Figs 20B, C ; 22A ). Antenna long (0.15 mm in holotype; 0.10–0.26 mm long in paratypes), extending to chaetiger 2; digitiform with more or less swollen region above mid-region; with cilia ( Figs 17A ; 18A ; 20B, C ; 22A ). A pair of nuchal organs present, as narrow, deep, short and slanted slits placed on dorso-lateral sides of posterior prostomium, more or less convex in shaped; dense internal ciliation not reaching to outer margin of slits; without pigmentation ( Fig. 20 B–C). Mouth with three buccal lips; two placed anteriorly, one placed posteriorly and extending to anterior margin of chaetiger 1, with five longitudinal folds; a Y-shaped gap present between anterior lips (also in all paratypes) ( Fig. 18B ).

A dorsal ciliary band (dcb) present on mid-dorsal transversal line of each prebranchial and branchial chaetiger. A pair of short dorsal ciliary bands (sdcb) present in a transverse line, just posterior to base of each branchia ( Figs 20 A–C; 21C). Intersegmental ciliary band (iscb) present, located between segments, originating near notopodia ( Fig. 22B ). Ciliary bands absent on ventral side of body ( Fig. 21 A–B).

Branchiae numbering 18 pairs in holotype, 10–21 pairs in paratypes, starting on chaetiger 4; flattened, foliaceous with rounded tip, weakly swollen in middle branchial region ( Fig. 20A ); dense ciliary bands on both sides of branchiae; ( Figs 17A ; 18A ; 19A ; 21 A–C); branchiae usually shorter than segment width; 220 μm long in anterior region, 233 μm long in middle region, 294 μm long in posterior region; posterior five pairs longer (length / width mostly between; 2.9–8.1).

Notopodial postchaetal lobes starting in chaetiger 1; short, cirriform on first two chaetigers; increasing in length and becoming stout, clavate shaped on chaetiger 3; stout, long, finger-like, with bases symmetrically inflated after chaetiger 3 to end of branchial region; becoming longer, stout and finger-like in postbranchial region; long, thin and filiform in posterior-most region ( Figs 17A ; 18A , C–F; 19B; 20A–B; 21A–C; 22B–C). Neuropodial postchaetal lobes present in chaetigers 1–11 as short ridges; becoming indistinct towards chaetiger 11 ( Figs 17A ; 22B ).

Lateral sense organs present on all chaetigers, located between noto- and neuropodia, just posterior to notopodial postchaetal lobes; elliptical with irregularly clustered pores from prebranchial region to middle part of branchial region; more or less C-shaped with regularly clustered pores from middle part to posterior part of branchial region; straight line-shaped with regularly clustered pores from posterior part of branchial region to end of body ( Fig. 22 A–E); with 30–35 pores in prebranchial region (long axis of organ: 9–10 μm), with 60–62 pores (long axis: 11–12 μm) in branchial region, with 65–68 pores (long axis: 21–22 μm) in posterior part of branchial region, with 80–82 pores (long axis: 24–25 μm) in posterior region; with flexible cilia distinctly protruding from opening or embedded into pore.

Three main types of chaetae present on chaetigers: limbate, capillary and modified neurochaetae. Limbate chaetae of two types; first type present only in notopodia of chaetigers 1–15, numbering 15–27 arranged in three rows, ca. 150 µm long, thin and straight with fibrils along edge (hirsute), dorsally directed side, colorless; second type present only in neuropodia of chaetigers 1–15, numbering 14–42, arranged in four rows, ca. 144 µm µm long, slightly wider and sigmoid with fibrils along edge (hirsute), dorsal to ventral in fascicle, colorless ( Figs 17A ; 18D ; 19B ).

Capillary chaetae starting in noto- and neuropodia of chaetiger 16 and present in all subsequent chaetigers; in middle notopodia numbering 5–8, arranged in two rows, ca. 276 μm long; in posterior notopodia numbering 2–5, arranged in one row, ca. 282 μm long; in middle neuropodia numbering 10–18, arranged in 2–3 rows, ca. 244 μm long; in posterior neuropodia numbering 4–7, arranged in one row, ca. 323 μm long.

Modified neuropodial chaetae from chaetiger 39 (30–40 in paratypes) to pygidium, numbering 4–8 in each neuropodium, accompanied with thin capillary chaetae; as curved hooks (90° degree towards terminal region), with a strong hood, hood with numerous fibrils and encompassing curved end of shaft except for a small subdistal gap; with a short, thin and fragile arista arising from subterminal region (in most specimens arista is missing) ( Figs 17 B–D; 19C–G; 21D); superior chaetae longer, ca. 62 μm long.

Pygidium flattened, rounded, with three cirri ( Figs 18C ; 19H ); two cirri placed ventro-laterally long (91–96 μm) and digitiform; one cirrus placed mid-ventrally short (12.5 μm) and subtriangular.

Reproduction. Some specimens of this species from the Sea of Marmara had sperm packages within coelomic cavities of chaetigers 21–29 and present to the end of the body. The gametous specimens had red speckles near notopodia along the body ( Fig. 19I ).

Remarks. Aricidea (Acmira) katzmanni n. sp. is mainly characterized by having a digitiform antenna with a swollen region near its middle; by the shape of its different types of limbate chaetae; by possessing notopodial postchaetal lobes with symmetrically inflated bases; by lacking notopodial papillae; by its branchiae becoming longer towards the posterior region and by having curved hooks with a very strong hood and a fragile arista.

The species most morphologically similar to A. katzmanni n. sp. are A. cerrutii , A. catherinae , A. philbinae and A. pigmentata . All of them have a curved modified neurochaeta with a strongly or weakly developed hood. However, A. katzmanni n. sp. differs from these species in terms of the following characters: (1) the shape and size of the antenna (long, digitiform with a swollen region near the mid-region in A. katzmanni n. sp.; long, digitiform with a central extension in A. catherinae ; short and clavate in A. philbinae ; short and digitiform in A. cerrutii ; claviform and swollen at base in A. pigmentata ); (2) the notopodial papillae (absent in A. katzmanni n. sp., A. cerrutii and A. pigmentata ; present in the postbranchial region of A. catherinae ; present in the branchial region of A. philbinae ; (3) the shape of the modified neurochaeta (as curved hook with a strong hood, very short and fragile arista in A. katzmanni n. sp.; as curved hook more or less tapering to terminal region with a weak hood and a long arista in A. catherinae and A. philbinae ; as curved hook with a strong hood, but without arista in A. cerrutii ; as curved hook with a weak hood, but without arista in A. pigmentata ).

Etymology. This species name is dedicated to Dr.Werner Katzmann who made contributions to the understanding of polychaete diversity in the Mediterranean Sea.

Habitat and Distribution. This species was found in soft substrata and Posidonia oceanica biotope between 7 and 50 m depths in the Sea of Marmara, between 3 and 56 m depths in the Aegean and Levantine Seas.

Figures

FIGURE 17. Aricidea (Acmira) katzmanni n. sp., Holotype (ESFM-POL/2013-974).A, Lateralview of anterior end; B, Modified neurochaeta with arista on chaetiger 41; C, Modified neurochaeta of chaetiger 47; D, Modified neurochaeta of chaetiger 50. Scale bar: A, 408 µm; B, 31 µm; C, 33 µm; D, 33 µm.

FIGURE 18. Aricidea (Acmira) katzmanni n. sp. A, Dorsal view of anterior end, paratype (ESFM-POL/2013-994); B, Ventral view of anterior end, paratype, (ESFM-POL/2013-977); C, Lateral view of pygidium, paratype (ESFM-POL/2013-977); D, Cross section of chaetiger 17, paratype (ESFM-POL/2013-981); E, Cross section of chaetiger 21, paratype (ESFM-POL/2013- 981); F, Cross section of chaetiger 36 (ESFM-POL/2013-981). Scale bar: A, 315 µm; B, 309 µm; C, 124 µm; D, 302 µm; E, 371µm; F, 459 µm.

FIGURE 19. Aricidea (Acmira) katzmanni n. sp. A, Lateral view of anterior end, holotype (ESFM-POL/2013-974); B, Lateral view of mid-branchial region, notopodial postchaetal lobes, holotype; C, Modified neurochaeta of chaetiger 41, holotype; D, Modified neurochaeta of chaetiger 55, holotype; E, Modified neurochaeta of chaetiger 56, holotype; F, Modified neurochaetae of posterior chaetiger, holotype; G, Modified neurochaeta of posterior chaetiger (ESFM-POL/2013-977); H, Lateral view of pygidium (ESFM-POL/2013-977); I, Red speckles on neuropodia of chaetigers 21-29 (ESFM-POL/2013-977). Abbreviation: rds, red speckles. Scale bar: A, 182 µm; B, 68 µm; C, 36 µm; D, 31 µm; E, 33 µm; F, 31 µm; G, 36 µm; H, 96 µm; I, 152 µm.

FIGURE 20. Aricidea (Acmira) katzmanni n. sp. A, Dorsal view of anterior end, paratype, short dorsal ciliary bands (ESFM- POL/2013-994); B, Dorso-lateral view of anterior end, paratype (ESFM-POL/2013-994); C, Dorsal view of anterior end, paratype (ESFM-POL/2013-43). Abbreviations: clcb, crown-like ciliary band; cs, ciliary slits; dcb, dorsal ciliary band; no, nuchal organ; sdcb, short dorsal ciliary band. Scale bar: A, 212 µm; B, 83 µm; C, 88 µm.

FIGURE 21. Aricidea (Acmira) katzmanni n. sp. (paratype, ESFM-POL/2013-994).A, Lateral view of anterior end; B, Lateral view of posterior branchial chaetigers; C, Dorsal view of mid-branchial chaetigers, short dorsal ciliary bands; D, Modified neurochaeta of posterior chaetiger. Abbreviations: clcb, crown-like ciliary band; dcb, dorsal ciliary band; lso, lateral sense organ; sdcb, short dorsal ciliary band. Scale bar: A, 218 µm; B, 141 µm; C, 133 µm; D, 2 µm.

FIGURE 22. Aricidea (Acmira) katzmanni n. sp. (paratype, ESFM-POL/2013-986).A, Lateral view of anterior end; B, Lateral view of chaetigers in branchial region, intersegmental ciliary bands and lateral sense organs; C, Notopodium of posterior chaetiger with lateral sense organ, arrow indicated a cilia on body; D, Lateral sense organ of mid-branchial region in C shape; E, Lateral sense organ of posterior chaetiger, in straight shape. Abbreviations: bran, branchia; clcb, crown-like ciliary band; copcl, cilia of postchaetal lobe; cs, ciliary slits; iscb, intersegmental ciliary band; lso, lateral sense organ; ntpcl, notopodial postchaetal lobe. Scale bar: A, 144 µm; B, 62 µm; C, 21 µm; D, 6 µm; E, 11 µm.