Pistella papillosa Londoño-Mesa 2009, comb. nov.

Pistella papillosa (Tourtellotte & Kritzler, 1988) comb. nov.

Figures 15 A-H

Scionella papillosa, Tourtellotte & Kritzler, 1988:79–81, Fig. 1.

Pista papillosa, Saphronova, 1991:246.

Type material: Paratypes USNM 99377 (1) Sanibel Island, Florida (26°17′24″N 82°19′57″W), 6.XII.1983; 16m. (Holotype USNM 99376 (1) not examined).

Additional material: Gulf of Mexico: Veracruz State: UANL 6501 (1) Pajaros, 30.V.2003; Pl.1. Antilles: ZMA V.Pol. 7541D (1) Awa di Oospunt, Hylech, Curaçao, 14.IX.1975; 3–4m.

Description: Paratype complete, in two fragments, anterior fragment with 30 segments, 12.5mm long; thorax 7mm long, 0.7mm wide (Fig. 15A). Posterior fragment with 82 segments, 15.1mm long. Tentacular membrane reduced; eyespots absent; tentacles long and thin. Upper lip long, folded dorsally. Lower lip small. First pair of lateral lappets elongate laterally (Fig. 15B); second pair smaller than first, laterally covering segment 2. Third pair of lateral lappets more dorsal than first pair (Fig. 15C). One pair of branchiae on segment 2, pompom-like (branching filaments in a spiralled arrangement), usually one of the branchiae longer, as long as about 7 thoracic segments. Nephridial papillae on segments 6–7, almost inconspicuous. Fifteen ventral shields, equal-sized, from segment 3; first two shields shorter, rectangular, then, shields trapezoidal, all of same size. Notochaetae smooth and symmetrically bilimbate, distally pointed, in two lengths with similar shape alternating long and short in the same fascicle (Figs 15 D-F). Anterior thoracic neuropodia with 10–12 uncini per tori, and posterior thoracic uncini with 8–10 uncini per tori. Thoracic uncini (Fig. 15G) MF:5–6:5– 6:4–5 PP and PF absent; Oc concave; Cp with 3 series of teeth over a curved MF; USr short, flat; SrP short, poorly developed; SrA not seen; LSr convex; AP long, rounded; AF absent; Bs strongly convex. Abdomal neuropodia with 5–7 uncini per tori or less in posterior abdomen; MF:4–5:4–5:3–4, PP and PF absent, Oc curved; Cp with 3 series of teeth over curved MF; USr flat; SrP absent, LSr convex; AP and AF absent; Bs strongly convex. Abdominal neuropodia flat, with long tori, until segment 35; then, tori shorter through posterior end. Last neuropodia closer to each other. Pygidium smooth, without papillae (Fig. 15H).

Staining pattern: Lateral lappets on segments 1 and 3, dorsum on segments 2–4 and anterior margin of the ventral shields stain deeply (Figs 15 A-C). All ventral shields stain deeply, with a lighter line on the posterior edge (Fig. 15A); gap between shields papillate; papillae in two groups laterally to a ventral middle line. The remaining thoracic and abdominal structures exempt from staining.

Variations: Additional specimen has 80 segments, 8mm long, thorax 3mm long, 0.5mm wide, with abdomen damaged by segments 25–30.

Discussion: Saphronova (1991) considered that Scionella papillosa belonged to Pista, because of the presence of one pair of pompom-like (bottle-brush) branchiae on segment 2, and notochaetae with smooth tips. But Scionella has one pair of branchiae on segment 4 and notochaetae distally serrated. On the other hand, Pista is characterized by uncini with long posterior process and filament in all thoracic uncinigers. Thus, since this species has one pair of bottle brush-like branchiae in segment 2, and all thoracic uncini without a posterior process and posterior filament but with the base strongly curved and convex, this species belongs to Pistella Hartmann-Schröder, 1996.

Type locality: Sanibel Island, Florida, USA.

Distribution: Florida, Curaçao. From shallow water to 16m.