Lamispina keeli, Salazar-Vallejo, 2014

Salazar-Vallejo, Sergio I., 2014, Revision of Pherusa Oken, 1807 (Polychaeta: Flabelligeridae), Zootaxa 3886 (1), pp. 1-61 : 51

Lamispina keeli n. sp.

Figure 22

? Pherusa .— Milligan, 1984:47.17, Figs 47.11–12.

Type material. Gulf of Mexico, Florida. Holotype ( USNM 129213 ), RV Sofla, Sta. 05 (26°45'42" N, 84°00'08" W), 90 m, 1 May 1981.

Additional material. Two anterior fragments ( USNM 89715 ), off Port O’Connor , Texas, U.S.A., R.V. Stocs, Sta. 1.3 (27°34' N, 96°07' W), 134 m, no further collection data (both juveniles already dissected; 4–4.5 mm long, 1 mm wide, 15–17 chaetigers; most chaetae broken) .

Description. Holotype (USNM 129213) complete, slightly tapered, rounded at both ends, whitish, depressed ( Fig. 22A ); distorted because of label pressure; 10 mm long, 2 mm wide, cephalic cage 2.5 mm long, 35 chaetigers. Tunic thick, with large sediment particles along a wide dorsal area, lateral areas with smaller paticles but parapodia covered by tunic; ventral surface with small particles ( Fig. 22B, C ). Body papillae long, capitate, larger laterally. Segmentation indistinct dorsally, ventrally better defined at both ends.

Cephalic hood barely exposed, short, margin papillose. Prostomium low; eyes large, reddish-brown ( Fig. 22D ). Caruncle short, triangular. Palps lost; palp keels low, rounded. Lateral and dorsal lips fused, ventral lip reduced.

Branchiae lost, apparently arranged in a single series; four scars laterally continuous, of same width, and the other four branchial filaments separated into two lateral groups, inner branchial scars wider than external ones. Nephridial lobes not seen.

Cephalic cage with a few chaetae, longer chaetae as long as about ¼ body length, slightly longer than half body width. Chaetigers 1–2 forming cephalic cage; chaetae arranged in short groups, two noto- and two neurochaetae per bundle.

Anterior dorsal margin of first chaetiger papillose, with large sediment particles. Chaetigers 1–3 of similar length. Chaetal transition from cephalic cage to body chaetae abrupt; lamispines present from chaetiger 3. Gonopodial lobes not seen.

Parapodia low transverse folds, lateral. Medial neuropodia ventrolateral. Notopodia with two large papillae throughout the body (glandular, methyl green affinity). Neuropodia projected lobes with two large papillae (not glandular, not stained in methyl green). Noto- and neuropodia close to each other.

Medial notochaetae reduced to one per bundle, as long as ¼–1/5 body width; all multiarticulated capillaries, basal articles medium-sized, becoming very long medially and distally ( Fig. 22E , insets). Neurochaetae multiarticulated capillaries in chaetigers 1–2; lamispines from chaetiger 3, transparent, arranged in transverse series, 2–3 in chaetigers 3–4 ( Fig. 22F ) and in far posterior ones, 4–5 lamispines per bundle in medial chaetigers ( Fig. 22G ); tips bidentate; apparently hooded.

Posterior end rounded; pygidium with anus terminal, without anal cirri.

Etymology. This species is named after Geoffrey Keel, collection manager in the National Museum of Natural History (USNM), Washington, in recognition of his very valuable and relentless help in searching and providing specimens, or other material support for our studies. The epithet is a noun in the genitive case.

Remarks. Lamispina keeli n. sp. and L. amoureuxi n. sp. differ from other species in the genus by having large sediment particles on their tunic. They can be separated because of the relative extent of sediment particles on their bodies, and by the start and type of lamispines. In L. keeli sediment particles are present along the dorsal surface, lamispines start in chaetiger 3, and their tips are bidentate with a distinct, long accessory tooth, whereas in L. amoureuxi sediment particles completely cover the body, lamispines start in chaetiger 2, and their tips are entire, without an accessory tooth.

The juveniles studied by Milligan (1984) might belong to this species because they have a poorly developed cephalic cage, and long lamispines starting in chaetiger 3; however, these specimens have more notochaetae per bundle and there are no large sediment particles on their dorsal surface. These differences in chaetal abundance cannot be confirmed because of the state of the Texas specimens, although this number might change during ontogeny. Better specimens would help resolve this issue.

Type locality. Northeastern Gulf of Mexico, Florida, in 90 m depth .

Distribution. Northern Gulf of Mexico, from Texas to Florida, in soft bottoms at 90– 134 m.

Figures

FIGURE 22. Lamispina keeli n. sp. A. Holotype (USNM 129213), twisted, anterior region in dorsal view. B. Anterior end, dorsal view. C. Anterior end, ventral view. D. Head partly exposed (branchiae and palps lost; BS: branchial scar, PS: palp scar). E. Chaetiger 11, right parapodium, notochaetae and papillae (inset: basal, medial and distal regions). F. Same, neuropodium, lamispines (insets: tips). G. Chaetiger 30, right parapodium, neurochaetae (inset: tips of two chaetae). Scale bars: A: 1 mm, B, C: 0.7 mm, D: 0.4 mm, E, F: 110 µm, G: 90 µm.