Procerastea nematodes Langerhans, 1884

Nygren, Arne, 2004, Revision of Autolytinae (Syllidae: Polychaeta)., Zootaxa 680, pp. 1-314 : 96-98

Procerastea nematodes Langerhans, 1884 (Fig. 41A–E)

Procerastea nematodes Langerhans, 1884: 249 –250, fig. 5A–E; Potts 1911: 30 –31; Gidholm 1967: 210, figs 7I, 29G–J, 30–31; Hartmann­Schröder 1971: 187; Kirkegaard 1992: 262 –264, fig. 129A–C; Hartmann­Schröder 1996: 193; San Martín 2003: 456 –458, fig. 250A–E. Procerastea perrieri Gravier, 1900a: 35 –48, pl. 1, fig. 1–17; 1900b: 288–293, fig. 1–13; Fauvel 1923: 327, fig. 126A–C; Cognetti 1961: 305; Gidholm 1965: 36.

Procerastea sp Nygren & Sundberg 2003: GenBank sequences, 16S rDNA partial sequence AF474269 , and 18S rDNA partial sequence AF474315 .

Material examined. Madeira: 3 syntypes on slides NHMW 2514; USA: 1 spm (in author's collection for DNA analyses) California , Santa Catalina Island, Wrighley Marine Science center, floating dock outside laboratory, 33°26.7’N, 118°29.05’W, 0.5 m, algae, hydroids, Jan 2001.

Diagnosis: Procerastea with bidentate simple chaetae together with compounds in anterior 4 chaetigers, a trepan with 6–10 indistinct teeth, and a pharynx with minute sinuation.

Description. Length 5.6–7.4 mm for 51–55 chaetigers, width excluding parapodial lobes 0.2–0.3 mm at level of proventricle. Live specimens reddish ( Gidholm 1967).

Ciliation absent except for nuchal epaulettes ( Gidholm 1967).

Eyes confluent or separated; eye spots absent. Palps small, do not project in front of prostomium (Fig. 41A), fused. Nuchal epaulettes reaching over tentacular segment ( Gidholm 1967).

Median antenna reaching chaetiger 2. Lateral antennae and first dorsal cirri, length equal to median antenna. Dorsal tentacular cirri 2/3 as long as antennae, ventral pair 1/2 as long as dorsal pair. Dorsal cirri from chaetiger 2 absent. In one specimen with developing stolon, small papillae­like dorsal cirri present from chaetiger 15. Small indistinct cirrophores on tentacular cirri, and first dorsal cirri, present. Anterior appendages cylindrical ( Gidholm 1967) to clavate (Fig. 41A).

Parapodial lobes small, rounded conical. Single acicula in all chaetigers. Chaetiger 1 with 9–13 simple chaetae (Fig. 41B); chaetiger 2–4 with 2–3 compounds and 4–5 simple chaetae (Fig. 41C); from chaetiger 5 only compounds present (Fig. 41D), numbering 4–6 in anterior and median chaetiger, 3–4 in posterior. Simple chaetae with denticulation along "fusion line" (Fig. 41 C). Both simple and compound chaetae with small distal tooth (Fig. 41B–D); serration absent. Single thick bayonet chaetae (Fig. 41D), distally dilated, beginning at chaetiger 4.

Pharynx with indistinct sinuation anterior to proventricle. Trepan in tentacular segment, with 6–10 small teeth ( Gidholm 1967). Basal ring absent; infradental spines absent ( Gidholm 1967). Proventricle equal in length to 1,5 segments in chaetiger 4–5, with indistinct rows of muscle cells, not possible to count. Anal cirri equal to 1/2 body width.

Reproduction. Schizogamy by anterior scissiparity (Fig. 41E), behind chaetiger 13. Stolon­forming individuals found from June to October ( Gidholm 1967).

Morphology of epitokous stages.

Male. Description based on Gidholm (1965; 1967). Length c. 5 mm for 6+(20– 21)+(5–11) chaetigers. Frontal processes inflated distally. Tentacular cirri 2 pairs. Achaetous knobs not described. First dorsal cirri present, glandular nodes (=dorsal cirri?) in region a, other cirri lacking.

Female. Unknown.

Habitat. 40–50 m, stones, shells, and slag.

Distribution. North East Atlantic, North East Pacific (Santa Catalina Island).

Remarks. See remarks for Procerastea australiensis .

Procerastea parasimpliseta Hartmann­Schröder, 1992 (Fig. 42A–C)

Procerastea parasimpliseta Hartmann­Schröder, 1992a: 99 –101, fig. 4A–D.

Material examined. New Caledonia: holotype MNHN UC 226, 1 paratype ZMH P­ 20632, Mont Musorstom auf der Rippe der Îles Loyauté, 21°60'S 167°54.70'E, 300m, associated with a calcified hydrocoral, 22 Feb 1989.

Diagnosis. Stolon with only bidentate simple chaetae and thick, distally dilated, bayonet chaetae.

Description. Holotype and paratype are the anterior and posterior end of the same female stolon. Length 5.2 mm for 47 chaetigers, width 0.3 mm. Preserved material whitish. Ciliation not assessed.

Prostomium rounded with 2 pairs of eyes, with lenses, in trapezoid arrangement. Eyes small, not confluent (Fig. 42A); small eye­spots scattered on prostomium. Palps absent. Nuchal epaulettes not observed.

Median and left lateral antennae lost. Right lateral antenna reaching chaetiger 1. Dorsal tentacular cirri 3/4 as long as lateral antennae; ventral tentacalur cirri 2/3 as long as dorsal pair. Dorsal cirri difficult to assess since the stolon lies partly within a tube. Dorsal cirri seen in chaetiger 17–20. Anterior appendages cylindrical to slightly club shaped, dorsal cirri short, egg shaped.

Parapodial lobes indistinct. Chaetiger 19 with single acicula. Chaetal fascicle with 15– 17 simple chaetae in anterior chaetigers, 8 in posterior. Simple chaetae have distinct denticulations along "fusion line" (Fig. 42B, C). Simple chaetae with small distal tooth. Single thick bayonet chaetae, distally dilated (Fig. 42B), present in last 5 chaetigers. Pygidium lost.

Distribution. South West Pacific. New Caledonia. Only known from type specimen.

Remarks. The atokes of P. parasimpliseta is not known, thus the placement in Procerastea is provisional. Procerastea simpliseta Hartmann­Schröder, 1990 is the only other species with only simple chaetae in combination with a thick, distally dilated bayonet chaetae; the chaetae in P. parasimpliseta are bidentate, while unidentate in P. simpliseta .

Procerastea simpliseta Hartmann­Schröder, 1990 (Fig. 43A–C) Procerastea sp Hartmann­Schröder 1989: 34, figs 56–58. Procerastea simpliseta Hartmann­Schröder, 1990: 58 .

Material examined. Australia: holotype ZMH P­ 19971, Maclean, rocky shore south of city border of Yamba, algae, 18 Jan 1976.

Diagnosis. Procerastea with only simple unidentate chaetae in all chaetigers.

Description. Holotype incomplete, length 1.2 mm for 13 chaetigers (Fig. 43A), width 0.2 mm. Preserved material whitish, no colour markings. Ciliation not assessed.

Eyes almost confluent (Fig. 43A); eye spots absent. Palps do not project in front of prostomium (Fig. 43A). Nuchal epaulettes reach over tentacular segment (Fig. 43A).

Median antenna reaching chaetiger 3–4. Lateral antennae 2/ 3 in length of median antenna. Dorsal tentacular cirri and first dorsal cirri 2/ 3 in length of lateral antennae. Ventral tentacular cirri 1/2 as long as dorsal pair. Dorsal cirri from chaetiger 2 absent. Small indistinct cirrophores on tentacular cirri, and first dorsal cirri present. Appendages clavate (Fig. 43A).

Parapodial lobes small, rounded conical. Single acicula in all chaetigers. Chaetal fascicle with 5–6 simple chaetae with distinct denticulation along "fusion line" (Fig. 43B). Chaetae with one distal tooth (Fig. 43B); serration absent. Single thick bayonet chaetae, distally dilated (Fig. 43C), beginning at chaetiger 1.

Pharynx with minute sinuation anterior to proventricle. Trepan in chaetiger 1 with c. 10 indistinct teeth. Basal ring absent, infradental spines absent. Proventricle, equal in size to 2 segments, in chaetiger 3–4, with indistinct rows of muscle cells, not possible to assess. Posterior part lost.

Reproduction. Schizogamy by anterior scissiparity behind chaetiger 13. The holotype is the anterior fragment, but Procerastea sp is its detached female stolon. The stolon is not included in the type material and has not been examined. Hartmann­Schröder describes it as having swimming chaetae between chaetiger 7–15 and dorsal cirri from chaetiger 6–15.

Habitat. Intertidal, rocky shore, algae.

Distribution. South West Pacific. South East Australia.

Remarks. Procerastea simpliseta is unique among Procerastea to have only unidentate simple chaetae; P. parasimpliseta known from a female stolon, also have simple chaetae throughout, but the chaetae in P. parasimpliseta are bidentate.