Proceraea prismatica O.F. Muller 1776

Proceraea prismatica (O.F. Müller, 1776) (Fig. 26A–E)

Nereis prismatica O.F. Müller, 1776: 218; Fabricius 1780: 302 –303.? Nereis bifrons O.F. Müller, 1776: 218; Fabricius 1780: 303 –304. Amytis prismatica Savigny 1822: 46; Grube 1850: 311; Quatrefages 1866: 77. Nereisyllis prismatica Blainville 1828: 473.

Polybostrichus longosetosus Örsted, 1843: 31 –32, figs 62, 67, 71. Polybostrychus longisetosus Grube 1850: 311.

Polybostrichus longosetus Quatrefages 1866: 72.

Autolytus incertus Malmgren, 1867: 35 –36, plate 6, fig. 40A–E.

Proceraea gracilis Verrill, 1874a: 132; 1874b: 361, pl. 3, fig. 2; Webster & Benedict 1887: 723 – 724; Treadwell 1948: 30.

Autolytus prismaticus Chamberlin 1920: 12 B; Berkeley 1923: 209 –210; Wesenberg­Lund 1947: 24 –30, figs 10–12; 1950: 50–51, fig. 13D; 1953: 38–39; Chlebovitch 1962: 169 –171, fig. 2; Pettibone 1954: 249 –252, fig. 29A–B; 1963: 139–141, fig. 37D; Imajima 1963: 352, pl. 12, fig. 12; Imajima & Hartman 1964: 99 –100, fig. 21A–G.

Autolytus aurantiacus Berkeley & Berkeley 1938: 48.

Autolytus trilineatus Berkeley and Berkeley, 1945: 318 –320, fig. 1A–B; 1948: 69–70, fig. 100; Pettibone 1967: 5.

Proceraea prismatica Hamond 1967: 1 –4,fig. 3A–C; Hartmann­Schröder 1971: 184 –186, fig. 59E– I; Hamond 1972: 344; 1974; Kirkegaard 1992: 257 –259, fig. 127A–E; Hartmann­Schröder 1996: 190 –191, fig. 82A–E; Nygren & Sundberg 2003: GenBank sequences, 16S rDNA partial sequence AF474265, and 18S rDNA partial sequence AF474311.

Autolytus (Proceraea) trilineatus Banse 1972: 197 –198, fig. 3A–C.

Not Autolytus prismaticus Thorson 1946: 39 –40 (= Proceraea cornuta)

Material examined. Norway: holotype of Autolytus incertus SMNH 2439, Spitsbergen, Whalers point, 77°35'N 20°5'E, Aug 1864. USA: holotype of Proceraea gracilis YPM 24230, Jul 1874; holotype of Autolytus trilineatus USNM 32881, New Castle Island, Nanaimo, British Columbia, 18 Jun 1943. Iceland: 4 spms, Breidafjördur, 65°N 23°W, dredge, 50 m, 15 Jul 1991; 1 spm in author's collection for DNA analyses, 64°15.5'N 22°01.7'W, dredge, 40 m, 26 Jun 1999. Faroes: 1 spm (rear end in author's collection for DNA analyses), South of Vagar, 61°56.8'N 6°59.5'W, triangle­dregde, 76–78 m, bedrock, gravel, hydroids, 27 Jun 1997; 1 spm (rear end in author's collection for DNA analyses), East of Bordøy, 62°04.2'N 6°33.8'W, triangle dredge, 57–58 m, shellgravel, 4 Jul 1997.

Diagnosis. Proceraea with 3 longitudinal black lines.

Description. Length 12.5–17 mm for 57–75 chaetigers, width 0.4–0.55 mm. Live specimens white, with 3 longitudinal black lines along most of body; one line at each side of body and one middorsal; eyes dark red. Lines fades in preserved material, but are sometimes retained. Ciliation present on prostomium, nuchal epaulettes, and a few segments ventrally.

Eyes confluent (Fig. 26A, B); eye spots present (Fig. 26B). Palps in dorsal view projecting 1/4–1/3 of prostomial length, fused. Extension of nuchal epaulettes to beginning of chaetiger 1 (Fig. 26A).

Median antenna reaching chaetiger 12–14 (n=2). Lateral antennae and dorsal tentacular cirri, length 1/2 of median antenna. Ventral tentacular cirri 1/2 as long as dorsal pair. First dorsal cirri as long as or 2/3 of median antenna, second dorsal cirri as long as tentacular cirri. From chaetiger 1–27 cirri with usual alternation in direction, followed by 4 DDUU­groups, and 3–4 DDU­groups (n=2). Dorsal cirri from chaetiger 3, of equal length, 2/3 or equal to body width. Cirrophores on tentacular segment and first dorsal cirri present; cirrophores otherwise absent. All appendages cylindrical.

Parapodial lobes rounded conical, small. Anterior chaetigers with 2–3 aciculae, 1 in median and posterior. Chaetal fascicle with 10–13 compounds in anterior chaetigers, 5–10 in median and posterior. Compound chaetae with small distal tooth (Fig. 26D) in anterior chaetigers, more posterior with larger terminal tooth, still somewhat smaller than subdistal tooth; serration present. Single thick bayonet chaetae (Fig. 26E), beginning between chaetiger 7–25 (n=4).

Pharynx with 1 sinuation anterior and lateral to anterior half of proventricle (Fig. 26B). Trepan in chaetiger 1–2, with 18 unequal teeth, 9 large and 9 smaller (Fig. 26C); 1 large alternating with 1 small, arranged in 2 rings. Basal ring present; infradental spines absent (Fig. 26C). Proventricle equal in length to 2.5 segments in chaetiger 6–9 (Fig. 26B) with 31–32 rows of muscle cells (n=4). Anal cirri equal in length to body width at level of proventricle.

Reproduction. Schizogamy by anterior scissiparity. Two specimens with developing stolons behind chaetiger 13. Stolons found from February to December (Malmgren 1867; Chamberlin 1920; Berkeley 1923; Wesenberg­Lund 1947; Pettibone 1963; Hamond 1974).

Morphology of epitokous stages.

Male. No mature stolons examined. Örsted (1843), Wesenberg­Lund (1947), Pettibone (1963), and Hamond (1967; 1974) provide information on stolon morphology. Length c. 10 mm for 6+(23–35)+(21–30) chaetigers (Wesenberg­Lund 1947; Pettibone 1963). Information on colour pattern lacking. Median antenna reaching chaetiger 9–14 (Wesenberg­Lund 1947; Hamond 1967). Lateral bifid antennae, basal part 1/2 of total length, its rami of about equal length. Frontal processes present. Tentacular cirri 2 pairs (Wesenberg­Lund 1947). First dorsal cirri, longer than median antenna (Wesenberg­Lund 1947); achaetous knobs present (Hamond 1974). Cirri in region a reciprocally equal, slightly longer than cirri in region b, cirri in region c much shorter (Wesenberg­Lund 1947: fig. 12). Cirri in region a fusiform (Örsted 1843: fig. 62; Wesenberg­Lund 1947: fig. 12), cirri in region b cylindrical.

Female. Based on holotype of Autolytus incertus. Length 8 mm for 6+19+24 chaetigers width in region a 0.4 mm, width in region b 0.8 mm. Pettibone (1954) gives these measurements: 9 mm for 6+18+34 chaetigers. Preserved material without colour markings, live specimens with same colour pattern as in atokes (Pettibone 1954). Ciliation not assessed.

Prostomium with straight anterior margin. Nuchal epaulettes triangular, reaching half of chaetiger 1.

Median antenna reaching chaetiger 4–5. Lateral antennae and first pair of dorsal cirri, equal in length to median antenna. Tentacular cirri 2 pairs, dorsal pair 2/ 3 in length of median antenna, ventral pair 1/ 3 in length of dorsal pair. First dorsal cirri, equal in length to dorsal tentacular cirri; achaetous knobs present. Cirri in region a, equal to body width; cirri in region b longer than in region a, equal to body width; cirri in region c successively shorter towards the end, c. 1/3 of body width. Small indistinct tentacular cirrophores, cirrophores on all dorsal cirri, except in posterior part of region c, present. All appendages cylindrical.

Region a and b with 2 neuropodial aciculae; 3 anterodorsal, and 6–7 posteroventral notopodial aciculae in region b. Neuropodial chaetal fascicle with c. 10 compound chaetae. Notopodial chaetal fascicle with c. 20 swimming chaetae. Anal cirri lost.

Habitat. Hydroids, gravel, sublittoral.

Distribution. North Atlantic, North Pacific, Arctic.

Remarks. Proceraea prismatica is unique in having 3 black lines, other Proceraea with longitudinal lines have either 2 or 4 lines. Preserved specimens might be difficult to separate from similar taxa with the same length in nuchal epaulettes. Molecular data suggests that its closest relative is Proceraea hanssoni n. sp. (Nygren & Sundberg 2003). The suggested synonomy of Polybostrichus longosetosus is concluded from literature, synonymy of Autolytus incertus, Proceraea gracilis, and A. trilineatus is based on examination of type material.

Proceraea rubroproventriculata Nygren & Gidholm, 2001 (Fig. 27A–E)

Proceraea rubroproventriculata Nygren & Gidholm, 2001: 184 –187, figs 2D–E, 5A–E, 6A–D, 7; Nygren & Sundberg 2003: GenBank sequences, 16S rDNA partial sequence AF474276, and 18S rDNA partial sequence AF474322.

Material examined. USA: holotype (LACM­POLY 1964), 1 paratype (LACM­AHF POLY 1965), and additional 4 spms (2 mounted for SEM), Florida, Key Biscayne, Crandon marina, 25°43.4'N, 80°10.4'W, orange sponge, 0.5 m, 11 Mars 1971; 1 spm, Florida, Biscayne bay, 25°31–34’N, 80°12.3'W, Porites and small sponges Haliclona viridis, 1 m, 22 Feb 1971. Brazil: 1 spm mounted for SEM, 4 spms on slides, 4 spms in author's collection for DNA analyses and 1 additional spm, Baía de Paranaguá, west Ihla do Mel, 25°34.55'S, 48°19.19'W, dive, 10 m, boulders with epifaunal mat, 15 Aug 1998.

Diagnosis. Proceraea with anterior and posterior third of proventricle orange­red, and with 12+12 teeth in trepan.

Description. Length 4.2–10.7 mm for 35–53 chaetigers, width 0.2–0.25 mm. Live specimens without colour markings, transparent to weakly brownish or orange­red in anterior part, especially laterally; anterior and posterior part of proventricle red (Fig. 27A); parapodial bases in Brazilian specimens with 3 or 4 red spots in a transverse row; eyes red. Preserved material without colours. Ciliation present on prostomium, nuchal epaulettes, and a few segments ventrally.

Eyes confluent (Fig. 27A); eye spots present. Palps in dorsal view projecting 1/3–1/2 of prostomial length (Fig. 27A), fused. Nuchal epaulettes extending over tentacular segment (Fig. 27A).

Median antenna reaching chaetiger 13–16 (n=4). Lateral antennae and dorsal tentacular cirri, length 1/2–2/3 of median antenna. Ventral tentacular cirri 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, of equal length, 1/3–1/2 of body width (Fig. 27A). Cirrophores on tentacular segment and first dorsal cirri present; cirrophores otherwise absent. All appendages cylindrical.

Parapodial lobes rounded conical, small. Anterior chaetigers with 2 aciculae, 1 in median and posterior. Chaetal fascicle with 6–9 compounds in anterior chaetigers, 4–5 in median and posterior. Compound chaetae with small distal tooth in anterior 5 chaetigers (Fig. 27C), more posterior with large distal tooth (Fig. 27D); serration present. Single thick bayonet chaetae (Fig. 27E), beginning between chaetiger 1–15.

Pharynx with 1 or 2 sinuations anterior and lateral to proventricle (Fig. 27A). Trepan in chaetiger 2–3 (Fig. 27A), with 24 unequal teeth (Fig. 27B), 12 large and 12 smaller, 1 large alternating with 1 small, arranged in 2 rings. Basal ring present; infradental spines absent (Fig. 27B). Proventricle equal in length to 2–3 segments in chaetiger 7–9 with 30– 34 rows of muscle cells (n=4). Anal cirri equal in length to body width.

Reproduction. Unknown

Habitat. Among hydroids and sponges. 1–10 m depths.

Distribution. West Atlantic from Florida, USA to Baía de Paranaguá, Brazil.

Remarks. Live specimens are easily recognized by the colour of the proventricle; this colour, however do not preserve. It is most similar to P. paraurantiaca, P. filiformis and P. misakiensis, but may be separated from these taxa on its trepan with 12+12 teeth.