Neoamphitrite glasbyi, Londoño-Mesa, Mario H. & Carrera-Parra, Luis F., 2005

Londoño-Mesa, Mario H. & Carrera-Parra, Luis F., 2005, Terebellidae (Polychaeta) from the Mexican Caribbean with description of four new species, Zootaxa 1057, pp. 1-44 : 22-23

Neoamphitrite glasbyi sp. nov.

Figures 6 A–E

Material examined: Mexican Caribbean: Holotype ECOSUR 0 0 56, R/V “Edwin Link”, sta. 2783, Off Majahual (18°41’85’’N 87°41’58’’W), 24 Aug. 1990, 59 m.

Etymology: This species is dedicated to Chris Glasby, for his great contributions to the knowledge of Polychaeta Terebellidae .

Description: Holotype complete, with 82 segments, 21 mm long; thorax 13 mm long, 2.5 mm wide ( Figures 6 A–B). Tentacles short. Tentacular membrane dorsally reduced, developed laterally, surrounding lower lip. Eyespots absent. Upper lip with well developed free edge, projecting forwards. Lower lip swollen, conspicuous. Lateral lappets small, present only on segment 3; fourth segment with a small swelling near the base of notopodia and nephridial papillae, not considered as a true lappet. Three pairs of branchiae, branched, starting from segment 2; first pair longer, second pair inserted slightly laterally; branchiae with short and stout stalk, three levels of ramification, and short, digitate tips. Eight pairs of nephridial papillae, rounded, small, starting from segment 3, placed between noto­ and neuropodia; first two pairs of papillae longer than the others. With 14 ventral shields, starting from segment 2; first two shields swollen, lateral edge of third shield shorter, shields 4–14 equal­sized, broader than long ( Figure 6 B); midventral groove present from posterior thorax to pygidium. Notopodia from segment 4, extending for 39 segments. Notochaetae curved, subdistally bilimbate and distally serrated, in two sizes ( Figures 6 C–D); convex side with irregular serrations, damaged limb. Neuropodia from segment 5, with uncini arrange in single rows from segment 5–10, in double rows from segments 11–41, in face to face position, in single rows from segment 42 until pygidium. Thoracic neuropodia longer than abdominal ones, the latter poorly developed. Thoracic and abdominal uncini similar to each other, uncini with dental formula MF:4–5:5–6:8–10 ( Figure 6 E). Upper subrostrum wide and rounded, with visible subrostral process; subrostral appendix not visible, lower subrostrum rounded, without anterior process; basis rounded, finishing in a developed posterior process (heel­like), without filament; occipitium long and convex (long neck); capitium with a long pointed main fang. Pygidium reduced, with about 10 visible papillae, better seen with methyl stain.

Remarks: Only three species of Neoamphitrite have been recorded in the Grand Caribbean Region: N. affinis ( Malmgren, 1866) from Spitsberg, Arctic Ocean, N. edwardsi (de Quatrefages, 1865) from St. Vaast, France, and Neoamphitrite sp. A from upper Gulf of Mexico. N. glasbyi sp. nov. differs from N. affinis and N. edwardsi by the number of pairs of nephridial papillae; N. affinis has 6 pairs, and N. edwardsi has 9 pairs, while N. glasbyi sp. nov has 8 pairs of nephridial papillae. Furthermore, N. glasbyi sp. nov. differs from Neoamphitrite sp. A Kritzler, 1984 in the number of lateral lappets and pairs of notopodia present; Neoamphitrite sp. A has lateral lappets on segments 2–4, and thorax with 29–32 pairs of notochaetigers, while N. glasbyi sp. nov. has lateral lappets only on segment 3, and thorax with 39 pairs of notochaetigers.

Type locality: Majahual, Mexican Caribbean.

Distribution: Only known from type locality.

Figures

FIGURE 6. Neoamphitrite glasbyi sp. nov. A. Lateral view; B. Ventral view; C. Chaetiger from segment 14; D. Chaetae from segment 14; E. Uncini from segment 11. Nicolea modesta: F. Lateral view; G. Ventral view; H. Chaetae from segment 9; I. Uncini from segment 9. Scale bars: A, B, F, G 1 mm; C 0.5 mm; D 0.05 mm; E, H, I 0.02 mm.