Biremis blandi Polloni, Rowe & Teal, 1973

Londoño-Mesa, Mario H., 2009, Terebellidae (Polychaeta: Terebellida) from the Grand Caribbean region 2320, Zootaxa 2320 (1), pp. 1-93 : 13-15

Biremis blandi Polloni, Rowe & Teal, 1973

Figures 3 A-J

Biremis blandi, Polloni, Rowe & Teal, 1973:170–175 ; Figs 1–4 ; Tab. 1.

Type material: Holotype USNM 47976 and Paratype USNM 47977 (1) Tongue of the Ocean , New Providence Island, Nassau, Bahamas (25°00'N 77°35'W), 19.XII.1970; 597m.

Additional material: Antilles : USNM 170580 (1) Saint-Vincent North Point of York (13°07'13"N 61°16'46"W), 24.IV.1989; 411m. USNM 170581 (1) Saint-Vincent North Point of York (13°07'12"N 61°17'02"W), 23.IV.1989; 429m. Gulf of Mexico : UMML 22.1013 (1) Cay Sal Bank, Florida Strait (24°16'N 80°02'W), R/V “Gerda” Sta. 142; 22.VI.1963; 545m.

Description: Holotype complete ( Figs 3A,B ), 60 segments, 46mm long, tentacular membrane 30mm wide, thorax 20mm wide (segment 20), and 5mm wide (segment 33). Body light greyish to whitish; thorax swollen up to segment 28, thereafter tapering to pygidium. Tentacular membrane wide and long, with margin thick, rounded, wavy and folded laterally toward thorax ( Fig. 3C ). Tentacles numerous, long and thin. Upper lip short, hidden by tentacular membrane. Lower lip small, hidden by hypertrophied swollen, ventrally bilobed segment 1. Ventral shields absent; midventral groove as two separated longitudinal non-glandular swollen muscular ridges. Nephridial papillae small, on segments 4–6, placed laterally near intersegmental lines, hidden by tentacular membrane folds ( Figs 3 D-F). Abdominal neuropodia small, bilobed, from segment 16 ( Figs 3G,H ); uncini avicular, in single rows ( Fig. 3I ), MF:5:5–6, PP developed as rounded button; PF long and thin, Oc short, almost straight; Cp with two series of teeth over long, thin fang; medial tooth in first row above the MF, thin, longer than lateral teeth, as long as 2/3 the MF; USr short, concave; SrP slightly visible; SrA absent; LSr long and concave; AP rounded; AF absent; Bs with two regions, anterior region longer and straight, and posterior convex and swollen. Pygidium terminal, smooth, and swollen for last 3 segments ( Fig. 3J ), compared with previous 15 segments.

Staining pattern: Nephridial papillae and surrounding areas stain deeply; they are only distinguishable under stain. The remaining structures do not stain significantly.

Variations: Paratype is complete, in average condition, previously dissected dorsally; 32 segments and 47mm long. Additional specimens have 55–66 segments, 60mm long, thorax 14–15mm wide in segment 10, and 5–6mm wide in segment 25. Nephridial papillae in paratype differ from those in holotype in that they are present on segments 2–3, as small rounded papillae and on segments 4–7 as larger, rounded papillae. Additional specimens have nephridial pore with swollen lip-shaped margin, on segments 8–11 in specimen from St.-Vincent, and on segments 9–12 in specimens from Key Sal Bank. Finally, specimens from St.-Vincent have pygidium with small concentric papillae on anal inner surface.

Discussions: The distribution of the species is expanded with the additional specimens to include localities near the type locality. All specimens were collected in deep water. The orginal description states “ thoracic segments (approximately 16) bearing only reduced lobes (one pair per segment) on the dorsolateral surface of the ventral ridges”. Original figure 3c shows this condition and names these lobes as papillae. Nevertheless, after the revision of the type and additional specimens, I have found that these papillae are not present on all thoracic segments, but only on anterior and middle thoracic ones, as mentioned in the variation.

The specimen from Key Sal Bank had some small tanaid crustaceans in the oral cavity, however, none of the other specimens contained these organisms. These crustaceans may inhabit the oral cavity, which is protected by the long tentacular membrane, and possibly feed on particles that the tentacles collect and pass to the mouth. Further analyses of this crustacean will be made in order to identify and describe the species.

Type locality: New Providence Island , Nassau, Bahamas .

Distribution: Florida Strait, St.-Vincent and Nassau, Bahamas. In deep water from 411 to 597m.

Figures

FIGURE 1. Uncini types: A. Avicular. B. Pecinate. MF: Main Fang. Sr: Subrostrum. USr: Upper Subrostrum. LSr: Lower Subrostrum. SrP: Subrostral Process. SrA: Subrostral Appendix. AP: Anterior Process. AF: Anterior Filament. Bs: Base. PP: Posterior Process. PF: Posterior Filament. Cp: Capitium. Oc: Occipitium. UOc: Upper Occipitium. LOc: Lower Occipitium.

FIGURE 2. Amaeana sp. 1., (USNM 90555): A. Ventral view. B. Dorsal view. C. Lateral View. D. Anterior ventral shields. E. Abdomen in ventral view. F. Thoracic notopodia from chaetiger 4. G. Fascicle of notochaetae from chaetiger 4. H. Abdominal notopodia from segment 16. I. Abdominal spines from segment 16. J. Pygidium. Scale bars: A,B,C,E: 1.7mm; D: 1.3mm; J: 3.8mm; F,H: 0.4; G: 0.7mm; I: 0.06mm.

FIGURE 3. Biremis blandi (Holotype 47976): A. Ventral view. B. Dorsal view. C. Anterior end in dorsal view. D.Anterior end in ventral view. E-F. Nephridial papillae. G. Neuropodia. H. Neuropodium from segment 16. I. Uncinus segment from 16. J. Abdomen in dorsal view and pygidium. Scale bars: A,B: 12mm; C,D: 9mm; E,F: 3.1mm; G: 1.3mm; H: 0.2mm; I: 0.02mm.

FIGURE 4. Enoplobranchus sanguineus (Syntype YPM 8909): A. Dorsal view. B. Anterior end in dorsal view. C. Anterior end in ventral view. D. Ventral view. E. Lateral view. F. Thoracic notopodia from segment 4. G. Notopodia from segment 5. H. Notopodia from mid-thoracic region. I. Abdominal notopodia. Scale bars: A,D,E: 5.5mm; B,C: 2.7mm; F: 0.4mm; G: 0.5mm; H: 0.5mm; I: 0.6mm.