Lamprophaea pettiboneae n. sp.

Fig. 22

urn:lsid:zoobank.org:act: 89978CB2-F100-4705-A7DF-D16AECD663CA

Leocrates chinensis: Hartman 1954: 622 (Bikini and Eniwetok atolls), 624 (Bikini Island), 625 (outside Bikini Atoll, Lidilbut Island, Eniwetok atoll), 628 (systematic list) (partim, non Kinberg, 1866); Pettibone 1970: 215 (listed specimen; not described nor illustrated) (partim, non Kinberg, 1866).

Type material. Western Pacific. Marshall Islands. Holotype (USNM 23961), Ralik Chain, Bikini Atoll, Bikini Island, outer reef, 178, VI, 14 Aug. 1947, F.M. Bayer & F.C. Zimmerman, coll.

Description. Holotype (USNM 23961), complete, damaged, bent spirally (Fig. 22A); right parapodia of chaetigers 10 (kept in container), and 13 (not found) previously removed. Body obconic, blunt anteriorly, tapered posteriorly, colorless, 42 mm long, 8 mm wide, 16 chaetigers. Anterior and posterior cirri on site, middle body ones missing.

Prostomium wider than long, wider anteriorly. Lateral antennae twisted, 1.5 times longer than prostomium, ceratophores distinct, antennae 1.5 times longer than palps. Palpophores pale, twice longer than palpostyles (Fig. 22B). Median antenna without tip, twisted, inserted between posterior eyes.

Eyes brownish, anterior and posterior eyes round, anterior ones twice larger, more distant to each other than posterior ones; in lateral view, eyes separated from each other (Fig. 22C).

Nuchal organs lobes L-shaped, pale, almost completely concealed by tentacular belt, leaving anterior portions of lateral branches exposed. Tentacular cirri damaged, twisted, longest ones reaching chaetiger 7 (probably longer but too delicate to be pulled backwards to its limit). Lateral cushions low, most distorted, entire, longitudinal striae barely visible.

Pharynx fully exposed, anterior margin crenulated. Upper and lower jaws single, submarginal, brownish, upper jaw larger than ventral one (Fig. 22D).

Dorsal cirri of middle chaetigers missing, relative length to body width unknown. Chaetigers 1–4 without notochaetae; notochaetae present along chaetigers 5–16, about 50 per bundle, in bundles, subdistally denticulate, denticles coarse. Notacicular lobes tapered (Fig. 22E, inset), shorter than neuracicular ones; neuracicular lobes oblique conical to rectangular, as long as wide (Fig. 22E). Neurochaetae about 30 per bundle, blades decreasing in size ventrally, 3–7 times longer than wide, blades bidentate, guard approaching subdistal tooth (Fig. 22F).

Posterior region damaged; prepygidial segment with dorsal cirri three times longer than ventral ones. Pygidium distorted by compression, anal cirri without tips, reach chaetiger 13.

Gonads present throughout body. Oocytes not seen, only testis.

Etymology. This species name is after the late Dr. Marian H. Pettibone in recognition of her many publications on polychaetes, and especially because of her revision of Leocrates Kinberg, 1866, which has been very useful for my efforts in understanding this group. The species-group name is a noun in the genitive case (ICZN 1999, Art. 31.1.2).

Remarks. Lamprophaea pettiboneae n. sp. belongs in the group of species provided with notochaetae from chaetiger 5. The dorsal pigmentation and the relative size of palpophores to palpostyles separate this species, such that L. pettiboneae resembles L. longicirrata (Treadwell, 1902) from the Antilles because they are both pale. However, in L. pettiboneae palpophores are twice longer than palpostyles, whereas they are three times longer in L. longicirrata.

Distribution. Only known from the type locality in the Marshall Islands, in shallow coralline substrates.