Caulleryaspis villamari, Salazar-Vallejo, 2017

Salazar-Vallejo, Sergio I., 2017, Cymonomus curvirostris Sakai 1965, Zoological Studies (Zool. Stud.) 56 (32), pp. 16-16 : 2-4

Caulleryaspis villamari sp. nov.

( Fig. 1 )

urn:lsid:zoobank.org:act:38C77F7E-EAC6-477D-A4DF-265F6B52CDB0

Sternaspis fossor : Villamar 1989:36, 40 (non Stimpson, 1853, partim).

Sternaspis scutata : Villamar & Cruz 2007:151 (non Ranzani, 1817, partim).

Type material: Eastern Tropical Pacific , Peru. Holotype ( USNM 1437645 ), and 10 paratypes ( USNM 1437646 ), R.V. Anton Bruun, Cruise 16, Sta. 635A (06°27'S, 80°56'W to 06°23'S, 80°55'W), off Isla Lobos de Tierra, 160 m, 5 Jun. 1966 (shield dirty orange in smaller specimens, becoming grayish; largest paratype with abdomen 17 mm long, 12 mm wide; smaller paratypes abdomen 3.5-5.0 mm long, 3-5 mm wide).

Additional material: Eastern Tropical Pacific, Ecuador. 23 specimens ( USNM 1437647), RV Anton Bruun, Cruise 18B, Sta. 777D (00°48'N, 80°37'W to 00°47'S, 80°37'W), 12 Sep. 1966, T.R. Menzies, coll. (small to very small specimens).

Description: Holotype ( USNM 1437645) complete, flaccid. Body grayish, with introvert exposed, shield grayish ( Fig. 1A ). Integument papillae mostly eroded; remaining ones short, filiform, with fine sediment particles. Body 32 mm long, 10 mm wide, abdomen 20 mm long, about 28 segments.

Prostomium hemispherical, opaque, distorted after being depressed ( Fig. 1B ). Peristomium oval, with abundant papillae (mostly eroded), extended as a wide band over prostomium. Mouth oval, as large as prostomium, completely covered by papillae (most eroded).

First three chaetigers with 16-18 falcate, thin introvert hooks per bundle, each with a narrow darker band subdistally, tips transparent, straight in smaller hooks, curved in larger ones. Genital papillae whitish, thick, corrugated, digitate protruding from intersegmental groove between segments 7 and 8. Pre-shield region with 7 segments; two capillary chaetae in segment 9, not visible in other segments (probably broken off).

Shield grayish, soft, with a thick integument layer, without sediment particles ( Fig. 1C ). Ribs faintly defined, no concentric lines. Anterior margins rounded; anterior depression shallow; anterior keels not visible. Lateral margins projected medially, reduced posteriorly. Fan truncate, not extended beyond posterior corners; median notch shallow, lateral notches shallow, displaced laterally; posterior margin barely crenulated.

Marginal chaetal fascicles include 10 lateral ones, chaetae in oval arrangement, and 8 posterior fascicles, chaetae in oblique series. Peg chaetae forming small, thick spines. Additional capillary chaetae broken, present in two fascicles on each side of peg chaetae.

Branchiae and interbranchial filaments lost. Branchial plates parallel, anteriorly expanded, rounded ( Fig. 1D ), with up to 14 longitudinal series of branchial scars.

Juveniles: Small paratypes with shields orange, soft ( Fig. 1E ), damaged. Smallest one with shield orange, with shallow anterior depression, anterior margins barely projected anteriorly, lateral margins straight, progressively thinner, posterior margin with shallow medial notch ( Fig. 1F ). Largest paratype with shield orange, anterior depression and posterior notch shallower than in smaller paratypes; lateral margins rounded, medially projected, posterior margin straight, barely crenulated ( Fig. 1G ).

Etymology: This species is named after Dr. Francisco Villamar, in recognition of his many publications on polychaetes from Ecuador. The epithet is a noun in the genitive case.

Remarks: Caulleryaspis villamari sp. nov. has a soft shield, not stiff or brittle as in Sternaspis Otto, 1821 . Because the shield is deprived of sediment particles, it resembles C. nana ( Zhadan, Tzetlin and Salazar-Vallejo 2017) n. comb., from Vietnam. Their main differences are indicated in the key below and include the color and presence of ribs in the shield; in C. villamari shields are yellowish to pale brown, with distinct ribs, whereas in C. nana shields are red to brownish without ribs. The juveniles are included here but with some hesitation because they are from abyssal depths. They differ from the juveniles another regional species, Sternaspis maureri Salazar-Vallejo & Buzhinskaja, 2013 because those herein regarded as related to C. villamari have orange shields with fans with small median notch, and poorly defined ribs, whereas in S. maureri shields are reddish with a distinct median notch, and ribs are better defined. Clarifying their affinities would need fresh material in order to assess their genetic attributes.

Distribution: Off northern Peru, in 160 m depth.

Key to species of Caulleryaspis Sendall & Salazar-Vallejo, 2013

(modif. Salazar-Vallejo & Buzhinskaja 2013)

1. Shield with sediment particles firmly adhered; shield surface not visible ........................................................... 2

- Shield without firmly adhered sediment particles; shield surface visible ................................................................. 4

2(1). Shield with anterior depression deep; peg chaetae robust ......................................................................................... 3

- Shield with anterior depression shallow; peg chaetae indistinct ................. C. laevis ( Caullery, 1944) ( Indonesia)

3(2). Shield with anterior margins angular; peg chaetae forming thick, large spines .............................................................. C. gudmundssoni Sendall & Salazar-Vallejo, 2013 (North Atlantic, Iceland)

- Shield with anterior margins rounded; peg chaetae forming thin, small spines .............................. C. fauchaldi Salazar-Vallejo & Buzhinskaja 2013 (Northeastern Pacific, Oregon to California)

4(1). Shield with lateral margins rounded, medially expanded, ribs barely visible ............................................................... C. nuda Salazar-Vallejo & Buzhinskaja 2013 (Northeastern Pacific, off Oregon)

- Shield with lateral margins straight to barely curved ...... 5

5(4). Ribs indistinct, shield dark red to brownish ....................... C. nana ( Zhadan, Tzetlin & Salazar-Vallejo, 2017) n. comb. ( Vietnam)

- Ribs distinct, shield yellowish to pale brown ...................... C. villamari sp. nov. (Eastern Pacific, Ecuador)

Figures

Fig. 1. Caulleryaspis villamari sp. nov. (A) Holotype (USNM 1437645), ventral view. (B) Same, close-up of prostomium, mouth and first series of hooks. (C) Same, shield. (D) Same, branchial plate after removal of branchiae and interbranchial filaments. (E) Smaller specimens (USNM 1437646), ventral view. (F) Close-up of shield of smallest one. (G) Close-up of shield of largest one. Scale bars: A = 2.7 mm, B = 0.6 mm, C, D = 1.3 mm, E = 2.8 mm, F = 0.4 mm, G = 0.7 mm.