Scyphoproctus edmondsoni, Magalhães, Wagner F. & Bailey-Brock, Julie H., 2012

Magalhães, Wagner F. & Bailey-Brock, Julie H., 2012, Capitellidae Grube, 1862 (Annelida: Polychaeta) from the Hawaiian Islands with description of two new species, Zootaxa 3581, pp. 1-52 : 42-43

Scyphoproctus edmondsoni sp. nov.

Figures 31 A–C, 32 A–E, 33 A

Material examined. Holotype: Oahu Island: Nuupia Pond, 21°25ʹ58.8ʺ N, 157°44ʹ52.8ʺ W, Environmental Monitoring and Assessment Program ( EMAP), State of Hawaii estuaries and bays, Oct. 2002, Sta. 20 ( USNM 1191161); Paratypes: same Sta. and date as holotype (20, USNM 1191162; 20, BPBM R3625).

Non– type material examined: Pearl Harbor, Middle Loch, on hull of U.S. S. ‘Machinist’ Floating Dry Dock, 27 Mar. 1996, 5 m, coll. R.C. DeFelice (1, BPBM R2318).

Description. Holotype 10 mm long, 0.4 mm wide for 59 chaetigers. Complete paratypes 2–11.5 mm long, 0.1–0.5 mm wide for 29–58 chaetigers. Body elongate, slender, widest on mid-thoracic chaetigers. Color in alcohol pale yellow.

Prostomium rounded anteriorly, inflated ( Figs 31 A, B, 32A, B); nuchal organs not observed; eyespots present as a pair of oval postero-lateral densely pigmented areas ( Fig. 31 B). Proboscis finely papillated ( Fig. 32 B). Peristomium achaetous, 1.5 longer than anterior thoracic segments ( Figs 31 A, 32A, B).

Thorax with 10–11 segments, including one achaetous segment (not the peristomium) and 9–10 chaetigers ( Figs 31 A, 32A). Thorax glandular, segments distinctly biannulate after chaetiger 5 with deep inter-segmental grooves and bilimbate capillaries ( Fig. 32 A); shallow inter-segmental groove transversing peristomium, achaetous segment and chaetigers 1–2 ( Fig. 32 B). First chaetiger biramous. Parapodial lobes well separated; notopodia inserted dorso-laterally and neuropodia laterally. Lateral organs present throughout, between noto- and neuropodia, closer to notopodia, easily observed after chaetiger 8. Genital pores not observed.

Transition between thorax and abdomen marked by change in shape of segments and chaetae ( Figs 31 A, 32A); abdominal segments multiannulated with hooded hooks throughout. Abdominal noto- and neuropodia with well separated glandular tori pads positioned anteriorly ( Figs 31 A, 32A). Anterior noto- and neuropodia with 10–12 hooks per fascicle, reducing to two notopodial hooks and 4–5 neuropodial hooks in far posterior. Abdominal hooks with short hoods, not extending beyond main fang ( Fig. 32 D, E). Hooks with multiple teeth, in frontal view with 3–4 rows; 3–4 in basal row, 4–5 in superior rows ( Fig. 32 D, E). One pre-pygidial segment with notopodial spines and neuropodial hooks. Additional segment incomplete, with two acicular hooks per notopodial lobe. Two inflated, heart-shaped anal cirri ( Figs 31 C, 32C). Branchiae absent.

Methyl green staining pattern. Anterior end and thoracic region stain uniformly light green ( Fig. 33 A), darker on posterior half of thorax ( Fig. 33 A). First two abdominal segments stain on the anterior and posterior halves of segments, leaving intra–segmental grooves and parapodial tori unstained; following abdominal segments stain only as a posterior band on each segment ( Fig. 33 A); posterior third of the body and pygidium stain uniformly green.

Distribution. Only known from Oahu, Hawaii.

Remarks. This new species differs from the other two species previously assigned to Pulliella , Scyphoproctus armata comb. nov., (Fauvel, 1929) and Scyphoproctus pseudoarmata ( Silva, 1965) comb. nov., by the number of thoracic segments, number of pre-pygidial segments with notoacicular spines and the shape of the anal cirri. For instance, S. armata comb. nov. has nine thoracic chaetigers with only capillaries, S. pseudoarmata has 12–13 and S. edmondsoni sp. nov., has 9–10. The number of pre-pygidial segments with notospines and neurohooks in S. armata comb. nov. is 8–11, in S. pseudoarmata comb. nov., it is 6–8 and in S. edmondsoni sp. nov., only one pre-pygidial segment has notospines and neurohooks. Anal cirri are digitate in S. armata comb. nov., filiform in S. pseudoarmata comb. nov., and inflated in S. edmondsoni sp. nov. Eyespots have not been reported in S. pseudoarmata , but these may be hidden below the peristomium.

The modified pygidium in all 56 specimens of S. edmondsoni sp. nov., had one of two stages in the posterior end: 1) pygidium forming a globular and glandular mass without distinct segments or chaetae or 2) pygidium with two distinct and inflated anal cirri and two fused segments not forming a distinct anal plate.

Etymology. This species is named after Dr. Charles Edmondson, a pioneer in studying Hawaiian marine invertebrates whose publications, especially the book entitled “The Reef and Shore Fauna of Hawaii” ( Edmondson 1933; 1946), have inspired and guided most of the current researchers.

Figures

FIGURE 31. Scyphoproctus edmondsoni sp. nov.: A, anterior end in lateral view; B, detail of anterior end showing prostomium, eyes and peristomium; C, posterior end with anal plate in lateral view.

FIGURE 32. SEM of Scyphoproctus edmondsoni sp. nov.: A, anterior end in lateral view; B, detail of anterior end showing delimitation of prostomium, peristomium, achaetous segment and chaetiger 1; C, posterior end segments showing anal plate; D – E, abdominal hooded hooks.

FIGURE 33. Scyphoproctus edmondsoni sp. nov.: A, MGSP of anterior end in lateral view. Scyphoproctus pullielloides: B, MGSP of anterior end in lateral view; C, MGSP of posterior end in dorsal view. Scyphoproctus sp.: D, MGSP of anterior end in lateral view; E, MGSP of posterior and anal plate; F, detail of stained pre- and post-chaetal parapodial lobes.