Myrianida pulchella Day, 1953

Nygren, Arne, 2004, Revision of Autolytinae (Syllidae: Polychaeta)., Zootaxa 680, pp. 1-314 : 152-158

Myrianida pulchella Day, 1953 (Fig. 76A–G)

Myrianida pulchella Day, 1953: 422 –424, fig. 4A–C; 1967: 287, fig. 12.13P–R.

Material examined. South Africa: holotype BMNH 1961.16.12, Cape Peninsula; paratype BMNH 1953.11.16.9, St. James, False bay, 26 Apr 1933.

Diagnosis. Myrianida with 40 unequal teeth in trepan, 1 large alternating with 1 much smaller.

Description. Length 21 mm for 109 stock chaetigers (20 mm for 92 stock chaetigers in paratype), length including stolons 24 mm, width 1.5 mm. Preserved material brownish, without colour markings; live specimens uniform salmon pink ( Day 1953) or coral red ( Day 1967). Ciliation as 2 trochs per segment (Fig. 76A).

Eyes separated; absence/presence of eye spots not possible to determine. Palps in dorsal view projecting c. 1/4 of prostomial length, fused (Fig. 76B). Nuchal epaulettes as grooves (Fig. 76A), extending to end of chaetiger 5 (end of chaetiger 4 in paratype), diverging after tentacular segment (Fig. 76A).

Median antenna reaching chaetiger 2–3. Lateral antennae and ventral tentacular cirri, length 1/3 of median antenna. Dorsal tentacular cirri 1/2 as long as median antenna. First dorsal cirri longer than median antenna, reaching chaetiger 4. Second dorsal cirri as long as lateral antennae. From chaetiger 1–27 cirri with usual alternation in direction, followed by 1 DDUU­group, 1 DDU­group, and 1 DUU­group, more posterior difficult to assess (in paratype 2 DDUU­groups, and 13 DDU­groups). Dorsal cirri from chaetiger 3, alternate in length; short cirri equals 1/2 of body width, long cirri equals 3/5 of body width. Cirrophores present on tentacular cirri, and all dorsal cirri. Cirrophores unequal, cirrostyles equal (Fig. 76C); short cirrophores 2/ 3 in length of long cirrophores (Fig. 76C); cirrophores longer than parapodial lobes; cirrophores on short cirri equal in length to cirrostyles, cirrophores on long cirri longer than cirrostyles (Fig. 76C). Anterior appendages and dorsal cirri on chaetiger 1–4 thick, swollen (Fig. 76A, B), more posterior cirri slightly flattened to cylindrical in shape (Fig. 76A, C).

Parapodial lobes large, with anterodorsal part prolonged (Fig. 76C). Unknown number of aciculae. Chaetal fascicle with c. 20 compounds in anterior chaetiger, 10–15 in median and posterior part of stock. Compound chaetae with small distal tooth; serration present (Fig. 76F, G). Single thin bayonet chaetae, beginning in stolonial region.

Pharynx with 1 sinuation anterior to proventricle (Fig. 76D). Trepan in chaetiger 6 with 40 unequal teeth; 20 large and 20 small; 1 large alternating with 1 much smaller (Fig. 76E), arranged in 1 ring. Basal ring present, thick; infradental spines absent (Fig. 76E). Proventricle equal in length to 8–10 segments, in chaetiger 9–16 with 100–105 rows of muscle cells (Fig. 76D).

Reproduction. Schizogamous reproduction by gemmiparity behind chaetiger 92 or 109.

Habitat. Unknown.

Distribution. South Africa; Cape and Natal.

Remarks. Myrianida pulchella is probably most closely related to M. pachycera but the two differ in many respects (see remarks for M. pachycera ).

Myrianida quindecimdentata ( Langerhans, 1884) comb. n. (Fig. 77A–E)

Autolytus quindecimdentatus Langerhans, 1884: 249 , pl. 15, fig. 3A–B; Gidholm 1967: 195 –198, figs 2B, 7F, 12, 23A–C, 24; Ben­Eliahu 1977: 86 –87, fig. 13; San Martín 2003: 494 –495, figs 272A–D, 273A–B; Nygren & Sundberg 2003: GenBank sequences, 16S rDNA partial sequence AF474260 , and 18S rDNA partial sequence AF474306 .

Autolytus lugens Saint­Joseph, 1887: 234 –235, pl. 12, fig. 116; Allen 1915: 606; Fauvel 1923: 318 – 319, fig. 122G; Cognetti 1954: 7, fig. 4a; 1961: 304; Gidholm 1965: 35.

Autolytus lugens mediterraneus Cognetti, 1953c: 123 –125, fig. 1; 1954: 7, fig. 4b; 1957: 68–69, fig. 13B–C.

Odontosyllis longicornis Hartmann­Schröder, 1960: 98 , figs 101–104.

Autolytus quinquedecimdentatus Hartmann­Schröder 1971: 178 ;?1979a: 82–83; Kirkegaard 1992: 233 –234, fig. 114; Hartmann­Schröder 1996: 185 –186.

Autolytus quindecemdentatus Giangrande et al. 2000 .

Material examined. Madeira: 2 syntypes, 1 atoke and 1 stolon, on slides, NHMW 2275. France: 9 spms (2 spms in formalin (rear end in author's collection for DNA analyses), 3 spms on slides (1 rear end in author's collection for DNA analyses), 4 spms in author's collection for DNA analyses), Banyuls­sur­Mer, 42°29.6'N 03°10.2'E, epibenthic sledge, 59– 62 m, tunicates and shells with epifauna, 18 Apr 2001. Norway: 1 spm (rear end in author's collection for DNA analyses), Trondheim, 63°28.4'N 10°00.0'E, 280– 230 m, gravel, 28 Jan 2002. Red Sea: holotype ZMH P­ 14759, and 1 paratype of Odontosyllis longicornis , ZMH P­ 14760, Djubal, 29 Oct 1957.

Diagnosis. Myrianida with brilliant white median antenna and anal cirri; trepan with 16–18 equal teeth.

Description. Length 2.8–5 mm (including stolon) for 29–50 chaetigers, width 0.20– 0.30 mm. Live specimens uncoloured, pale (Fig. 77A, B), to faintly yellowish, with white median antenna and anal cirri owing to presence of small light reflecting granules (Fig. 77A, B); eyes red. Ciliation as 1 troch per segment.

Eyes separated (Fig. 77B); eye spots present. Palps in dorsal view projecting 1/4–1/3 of prostomial length (Fig. 77B), fused. Extension of nuchal epaulettes from half of chaetiger 2 to half of chaetiger 3 (Fig. 77B).

Median antenna reaching chaetiger 10–15 (n=3). Lateral antennae and dorsal tentacular cirri, length c. 1/3 of median antenna (Fig. 77A). Ventral tentacular cirri 1/2 as long as dorsal pair. First dorsal cirri, length 2/3 of median antenna (Fig. 77A), second dorsal cirri as long as ventral tentacular cirri. Alternation in direction of cirri not assessed. Cirri equal, equal to 1/2 of body width (Fig. 77B). Cirrophores present on tentacular cirri, and all dorsal cirri. Cirrophores and cirrostyles equal; cirrophores shorter than parapodial lobes; cirrophores shorter than cirrostyles. All appendages cylindrical (Fig. 77A, B).

Parapodial lobes rounded, of medium size. Anterior chaetigers with 2–3 aciculae, 1–2 in median and posterior. Chaetal fascicle with 7–12 compounds in anterior chaetigers, 3–6 in median and posterior. Compound chaetae with small distal tooth; serration present (Fig. 77D). Single thin bayonet chaetae (Fig. 77E), beginning between chaetiger 1–13.

Pharynx with sinuation anterior and lateral to anterior half of proventricle. Trepan in chaetiger 1–3 (Fig. 77B), with 12–24 equal teeth in 1 ring (Fig. 77C). Thin basal ring present; infradental spines present (Fig. 77C). Proventricle equal in length to 1.5–2.5 segments (Fig. 77B) in chaetiger 7–11 with 25–29 rows of muscle cells (n=4). Anal cirri equal in length to 1.5–2 times body width at level of proventricle.

Reproduction. Schizogamous reproduction by gemmiparity of "quindecimdentatatype" behind chaetigers 22–47 ( Gidholm 1967). Stolon­forming individuals found from June to August ( Gidholm 1967) in Scandinavian waters, in the Mediterranean from May to October ( Cognetti 1957).

Morphology of epitokous stages. Gidholm provide information on stolons. Male c. 3 mm for 3+(18–22) chaetigers, tentacular cirri 2 pairs, anal cirri white as in stock. Female 3–4 mm for 6+(13–21)+(3+8) chaetigers, tentacular cirri 2 pairs, median antenna and anal cirri white as in stock.

Habitat. Subtidal, "coralligene". The investigation of Giangrande et al. (2000) indicates that M. quindecimdentata has an omnivorous diet since they found fragments of unicellular algae, crustacean fragments, sediment grains and spicules of sponges or ascidians in their stomach contents.

Distribution. Indian Ocean (Red Sea), North East Atlantic, Mediterranean.

Remarks. Most closely related to Myrianida hesperidium ; M. hesperidium lacks the conspicuous white median antenna and anal cirri. The synonymy of Odontosyllis longicornis is concluded from examination of type material.

Myrianida rangiroaensis (Hartmann­Schröder, 1992) comb. n. (Fig. 78A–F)

Autolytus rangiroansis Hartmann­Schröder, 1992b: 61 –62, figs 21–25.

Material examined. French Polynesia: holotype ZMH P­ 20701, and 2 paratypes ZMH P­ 20702, Rangiroa, lagoon, calcareous algae with sand, 7 Sept 1982.

Diagnosis. Myrianida with characteristic trepan, shared with M. dentalia : 2 large teeth laterally positioned with 7–10 dorsal teeth, and 14–17 ventral teeth; dorsal teeth smaller than ventral; large teeth fused with adjacent teeth. Unequal cirri with unequal cirrophores and equal cirrostyles. Large eye spots present.

Description. Length in preserved specimens 1–1.5 mm for 11–25 chaetigers, width 0.2 mm. Preserved specimens whitish, without colour markings; eyes reddish.

Eyes separated; eye spots present, large (Fig. 78A). Palps in dorsal view projecting 1/3 –1/2 of prostomial length (Fig. 78A), fused. Extension of nuchal epaulettes to half of chaetiger 2.

Most anterior appendages lost. From chaetiger 3–25 cirri with usual alternation in direction. Dorsal cirri from chaetiger 3, alternate in length; short cirri equals 1/3 of body width, long cirri equals 3/4 of body width. Cirrophores present on tentacular cirri, and all dorsal cirri. Cirrophores unequal, cirrostyles equal; cirrophores on short cirri 1/ 2 in length of cirrophores on long cirri; cirrophores on short cirri shorter than parapodial lobes, cirrophores on long cirri longer than parapodial lobes; cirrophores on short cirri equal in length to cirrostyles, cirrophores on long cirri longer than cirrostyles. All appendages cylindrical, including lost anterior appendages ( Hartmann­Schröder 1992b).

Parapodial lobes rounded, of medium–large size. Single acicula in all chaetigers. Chaetal fascicle with 6–8 compounds. Compound chaetae with small distal tooth; serration present (Fig. 78E). Single thin bayonet chaetae (Fig. 78F), beginning at chaetiger 2 or 3.

Pharynx with sinuation anterior to proventricle (Fig. 78B). Trepan in chaetiger 1–2, with 2 large teeth and 24–27 smaller (Fig. 78C, D); large teeth laterally positioned with 7– 10 dorsal teeth, and 14–17 ventral teeth (n=2); dorsal teeth smaller than ventral; large teeth are fused with adjacent teeth (Fig. 78D); teeth arranged in 1 ring. Basal ring present; infradental spines present. Proventricle equal in length to 3 segments in chaetiger 11–13 with c. 37 rows of muscle cells (n=1). Anal cirri equal in length to 1–1.5 times body width.

Reproduction. Unknown.

Habitat. Subtidal, amongst hydroids, bryozans, tunicates.

Distribution. Central Pacific. French Polynesia.

Remarks. The only other Myrianida with this kind of trepan is M. dentalia from North Pacific and North Atlantic. Myrianida dentalia has longer nuchal epaulettes, and smaller eye spots than does M. rangiroaensis . However, the two taxa are probably very closely related.

Myrianida rubropunctata ( Grube, 1860) comb. n. (Fig. 79A–F)

Sylline rubropunctata Grube, 1860: 87 –88, pl. 3, fig. 8.

Autolytus (Proceraea) ornatus Marion and Bobretzky, 1875: 44 –46, pl. 5, fig. 14, 14A–D; Saint­ Joseph 1887: 220 –221, pl. 10, fig. 98–99.

Proceraea rubropunctata Langerhans 1879: 579 –580, fig. 30 B.

Autolytus rubropunctatus Malaquin 1890: 989 ; Southern 1914: 40; Allen 1915: 604; Fauvel 1923: 314 –315, fig. 120 E–I; Cognetti 1957: 66 –67; 1961: 303; Hartmann­Schröder 1971: 182 –183, fig. 58D–G; Kirkegaard 1992: 236 –238, fig. 116A–D; Hartmann­Schröder 1996: 186, fig. 180A–D; San Martín 2003: 486.

Material examined. Italy: 2 syntypes ZMB Q4380, Porto Ré. France: 3 spms, MNHN A77, 1899; 2 spms, Roscoff, intertidal, 1962.

Diagnosis. Myrianida with 4 dorsal red spots on each segment.

Description. Length 8.8–16 mm for 69–106 chaetigers, width 0.3–0.4 mm. Preserved material yellowish­brownish without colour markings. Live specimens with 4 spots of red across each segment (Fig. 79A). Ciliation as 1 troch per segment.

Eyes confluent (Fig. 79A); eye spots present. Palps in dorsal view projecting 1/2–3/4 of prostomial length (Fig. 79A), fused. Extension of nuchal epaulettes from end of chaetiger 3 to end of chaetiger 4 (Fig. 79A).

Median antenna reaching chaetiger 12–14 (n=2). Lateral antennae and dorsal tentacular cirri, length 2/3 of median antenna. Ventral tentacular cirri 1/3–1/2 as long as dorsal pair. First dorsal cirri as long as median antenna, second dorsal cirri as long as ventral tentacular cirri. Alternation in direction of cirri not assessed. Dorsal cirri from chaetiger 3 alternate in length; short cirri 2/ 3 in length of body width, long cirri slightly longer than body width. Cirrophores present on tentacular cirri and all dorsal cirri. Cirrophores equal, cirrostyles unequal; short cirrostyles c. 2/ 3 in length of long cirrostyles; cirrophores equal to parapodial lobes; cirrophores shorter than cirrostyles. All appendages cylindrical.

Parapodial lobes rounded, of medium size. Anterior chaetigers with 3 aciculae, 1–2 in median and posterior. Chaetal fascicle with 10–15 compounds in anterior chaetigers, 4–9 in median and posterior. Compound chaetae with small distal tooth in first 10–15 chaetigers (Fig. 79C, D), gradually increasing in size after chaetiger 15 becoming equal to second tooth (Fig. 79E); serration present. Single thin bayonet chaetae (Fig. 79F), beginning between chaetiger 22–65.

Pharynx with 1 sinuation anterior to proventricle. Trepan in chaetiger 3, with 30–35 unequal teeth, 4–5 large teeth and 26–30 smaller; 1 large alternating with 4–10 small in 1 ring; small teeth of 2 sizes; large teeth and adjacent teeth fused (Fig. 79B). Basal ring present; infradental spines present. Proventricle equal in length to 3–5 segments (Fig. 79A) in chaetiger 9–17, with 32–38 rows of muscle cells. Anal­cirri lost.

Reproduction. Schizogamous reproduction of unknown type. Possibly by scissiparity, according to Saint­Joseph (1887), Malaquin (1890), and Allen (1915), a single stolon is always produced. Stolons found in May through July ( Allen 1915; Cognetti 1957).

Morphology of epitokous stages.

Male. Unknown.

Female. Saint­Joseph (1887) gives the following description: length c. 5 mm for 4+18+10 chaetigers, tentacular cirri 2 pairs. Same colour pattern as in stock.

Habitat. Sublittoral.

Distribution. North East Atlantic, Mediterranean.

Remarks. Myrianida rubropunctata is unique in its colour pattern. Together with M irregularis , the only Myrianida with a large distal tooth in its compounds. However, in M. irregularis the large distal tooth appear already after about 1–5 chaetigers, while in M. rubropunctata after more than 15–20 chaetigers, in addition the cirrophores are longer in M. rubropunctata than in M. irregularis , and the large teeth in the trepan are fused with the lateral teeth in M. rubropunctata , not so in M. irregularis . The structure of the trepan has hitherto not been correctly described and earlier authors have interpreted the trepan to have about 30 equal teeth.

Myrianida spinoculata ( Imajima, 1966) comb. n. (Fig. 80A–B)

Autolytus (Autolytus) spinoculatus Imajima, 1966: 32 –34, fig. 7A–H.

Material examined. Japan: holotype NSMT­Pol H­ 1, Tamano, Torishima, 2 m, May 1964.

Diagnosis. Myrianida with c. 20 equal teeth; nuchal epaulettes extending over chaetiger 2; equal cirri with equal cirrophores and cirrostyles.

Description. Holotype incomplete. Length 6 mm for 56 chaetigers, width 0.3 mm. Preserved material yellowish without colour markings; eyes reddish orange. Live specimens orange without colour markings ( Imajima 1966). Ciliation as 1 troch per segment.

Eyes separated; eye spots present. Palps in dorsal view projecting 1/4–1/3 of prostomial length. Extension of nuchal epaulettes to end of chaetiger 2.

Median antenna, tentacular cirri and first dorsal cirri lost. Lateral antennae reaching chaetiger 8. Second dorsal cirri, length equal to 1/2 body width. Alternation in direction of cirri not assessed. Dorsal cirri from chaetiger 3, of equal length, c. 1/3 of body width. Cirrostyles and cirrophores equal; cirrophores shorter than parapodial lobes; cirrophores shorter than cirrostyles. All appendages cylindrical.

Parapodial lobes rounded, of medium–large size. Single acicula in all chaetigers. Chaetal fascicle with 10–12 compounds in anterior chaetigers, 4–9 in median and posterior. Compound chaetae with small distal tooth (Fig. 80B); serration present. Single thin bayonet chaetae (Fig. 80B), beginning at chaetiger 15.

Pharynx with 1 sinuation anterior to proventricle (Fig. 80A). Trepan dissected, position not known, with about 20 equal teeth, arranged in 1 ring. Basal ring not possible to assess, infradental spines present. Proventricle equal in length to 4 segments in chaetiger 8–11 with 34 rows of muscle cells (Fig. 80A). Pygidium lost.

Reproduction. Unknown.

Habitat. Intertidal.

Distribution. North West Pacific. Southern Japan. Only known from type locality.

Remarks. Myrianida spinoculata is very similar to other taxa with equal cirri, and about the same number of equal teeth in trepan including M. arborea , M. brevipes , and M. edwarsi . Myrianida spinoculata may be separated from these taxa in longer nuchal epaulettes, reaching end of chaetiger 2, contrasting with beginning or middle of chaetiger 1 in M. arborea and M. brevipes , and at the most beginning of chaetiger 2 in M. edwarsi ; the number of teeth is about the same in M. spinoculata , M. arborea , and M. brevipes (c. 20) but slightly fewer than in M. edwarsi (24–34); the proventricle is longer in M. spinoculata measuring 4 segments compared with 2–2.5 segments in M. edwarsi and 1.5–2 segments in M. arborea and M. brevipes ; in addition M. spinoculata has 34 rows of muscle cells while M. arborea and M. brevipes has 20–23, and M. edwarsi has 23–31. Imajima describes the colour to be orange without colour markings for M. spinoculata and thus live specimens should be easy to separate from M. edwarsi that has orange­red lateral sides in pharyngeal region. Myrianida spinoculata is only known from this anterior fragment, and considering the large variation found in length of nuchal epaulettes, number of rows of muscle cells, and length of proventricle, in better described autolytine taxa, these are not very reliable characters for separation of these taxa. A larger material, and preferably genetic data, is needed to clarify the status of M. spinoculata .