Lamispina chilensis, Salazar-Vallejo, 2014

Salazar-Vallejo, Sergio I., 2014, Revision of Pherusa Oken, 1807 (Polychaeta: Flabelligeridae), Zootaxa 3886 (1), pp. 1-61 : 44-45

Lamispina chilensis n. sp.

Figure 18

Therochaetella chilensis Hartman, 1967:128–129 (partim).

Type material. Southeastern Pacific Ocean. Holotype ( USNM 56470 ) and one paratype ( USNM 1251914 ), off Santiago, Chile, RV Eltanin Antarctic Expedition, cruise 26, Sta. 752 (33°14' S, 71°47' W), 209 m, 26 Sep. 1963 (paratype anterior fragment 7 mm long, 1 mm wide, cephalic cage 3 mm long, 21 chaetigers) . Paratype ( USNM 1251915 ), off Santiago, Chile, RV Eltanin Antarctic Expedition, cruise 26, Sta. 753 (33°16' S, 71°47' W), 192 m, 26 Sep. 1963 (anterior fragment 5 mm long, 1 mm wide, cephalic cage 2.5 mm long, 18 chaetigers) .

Additional material. Southeastern Pacific Ocean. One specimen ( LACM 6532 ), off Santiago, Chile, RV Eltanin Antarctic Expedition, cruise 26, Sta. 752 (33°14' S, 71°47' W), 209 m, 26 Sep. 1963 (7 mm long, 1.5 mm wide, cephalic cage 4 mm long, 23 chaetigers; gonopodial lobes on chaetiger 5) .

Description. Holotype (USNM 56470) an anterior fragment, cylindrical, anteriorly swollen, posteriorly reduced in diameter from chaetiger 11 ( Fig. 18A ); 7.5 mm long, 1 mm wide, cephalic cage 3.5 mm long, 23 chaetigers (constricted region starts at chaetiger 12). Body papillae long, capitate, arranged in single transverse series at chaetigers 1–3, then in two transverse series; dorsal papillae longer, parapodial papillae long, ventral papillae shorter ( Fig. 18B ). All with a thin crust of fine sediment particles.

Cephalic hood exposed, short, margin papillated ( Fig. 18A ). Prostomium low cone, eyes not seen; caruncle short, triangular. Palp and branchial features observed in a non-type specimen (LACM 6532). Palps thick, slightly shorter than longest branchiae; palp keels low, rounded. Lateral lips well developed; ventral lip rounded, dorsal lip reduced.

Branchiae cirriform, arranged as a single row with eight filaments, larger ones slightly longer than palps. Nephridial lobes not seen.

Cephalic cage chaetae 3.5x longer than body width; chaetigers 1–3 forming cephalic cage. Chaetae arranged in short groups; chaetiger 1 dorsolateral, lateral in chaetigers 2–3; 4–5 chaetae per bundle.

Anterior dorsal margin of first chaetiger papillated, papillae as long as dorsal ones in following chaetigers. Chaetigers 1–3 increasing in size posteriorly. Chaetal transition from cephalic cage to body chaetae abrupt; lamispines from chaetiger 4. Gonopodial lobes on chaetiger 5, low, rounded, pale lobes with about 5 papillae.

Parapodia well developed; especially on anterior chaetigers (1–5). Parapodia lateral; medial neuropodia ventrolateral ( Fig. 18C ). Notopodia short triangular flat lobes, with one smaller prechaetal and two longer postchaetal papillae in anterior chaetigers (largest inferior to chaetae); posterior region with prechaetal papillae longer. Neuropodia rounded flat lobes, larger than notopodial ones, with one prechaetal and two postchaetal papillae (largest inferior to neurochaetae).

Medial notochaetae multiarticulate capillaries, arranged in short transverse series; articles short in small basal region, then long medially and distally ( Fig. 18D ), about 5 per fascicle, as long as 2/3 body width in anterior region, or as long as body width in constricted region. Neurochaetae multiarticulated capillaries in chaetigers 1–3; from chaetiger 4 anchylosed, aristate lamispines, arranged in transverse series, 7–8 per bundle ( Fig. 18E ), about as long as body width. Lamispines with anchylosed short articles basally and medially, distally hyaline, with long arista ( Fig. 18F ).

Posterior end unknown.

Etymology. This species is named after the country where it was originally found.

Remarks. Lamispina chilensis n. sp. resembles L. kerguelarum ( Grube, 1877) n. comb. because both have stiff body papillae, tapered or conical, and lamispines tapered with tips acuminate. These two species can be separated from each other by the start of lamispines, and by the number of notochaetae in medial segments, and transverse series of papillae per segment. In L. chilensis lamispines start in chaetiger 4, there are 5 notochaetae per bundle, and two transverse series of papillae per segment, whereas in L. kerguelarum lamispines start in chaetiger 3, its notochaetae are more abundant (9–12 per bundle), and it has more transverse series of papillae (4) per segment.

The combination introduced by Olga Hartman, Therochaetella chilensis , has been restricted based upon the holotype, and transferred to Trophoniella Hartman, 1959 ( Salazar-Vallejo 2012b).

Distribution. Only known from the type locality, off Santiago, Chile, in 192–209 m depth.

Figures

FIGURE 18. Lamispina chilensis n. sp. A. Holotype (USNM 56470) and paratype (USNM 1251914), holotype at left in dorsal view, head exposed, paratype in left lateral view. B. Paratype (USNM 1251914), anterior end, right lateral view. C. Paratype (USNM 1251915), chaetiger 18, cross section. D. Same, long papilla and notochaetal basal and medial regions. E. Same, chaetiger 15, left parapodium, lamispines. F. Same, basal, medial and distal regions. Scale bars: A: 0.9 mm, B: 0.3 mm, C, E: 0.1 mm, D: 50 µm, F: 35 µm.