Podocerus talegus lawai J. L. Barnard 1970

Podocerus talegus lawai

DIAGNOSIS OF MALE.—Lateral cephalic lobes rounded anteroventrally, eyes on strong lateral bulges divorced from anteroventral corners, red in formaldehyde, ochraceous in alcohol, with weak core of darker ochre; accessory flagellum 1-articulate but thick and elongate, antennae 1–2 long; coxa 1 strongly extended forward; article 6 on gnathopod 1 of normal expansion, slightly longer than article 5, palm about twice as long as posterior margin of article 6, defined by 2 or more spines, one of them thorny, dactyl with long inner serrations near apex, article 6 with long, anteriorly submarginal, semipinnate setal spines, article 5 with evenly bulging posterior lobe; article 2 of gnathopod 2 with quadrate anterodistal lobe, article 4 with small posterodistal cusp, palm undefined, occupying most of posterior margin of article 6, dactyl about two-thirds as long as article 6, palm fringed with long setae and medial face of hand with many stout but long setae, no palmar teeth showing laterally or marginally from medial view in young male but bearing mediosubmarginal, low, broad, crenulate distal process, next proximally a rounded smooth process and finally a small or large obtusely conical process, terminal male with these processes much enlarged and medial edge of article 2 heavily setose; article 2 of pereopods 1–5 of medium stoutness; outer ramus of uropod 1 about three-fourths as long as inner ramus, peduncle with ventrodistal sharp tooth of medium length between rami, outer ramus of uropod 2 about two-thirds as long as inner ramus, often appearing shorter from lateral view, uropod 3 small but with 3 apical-subapical spines; telson subcircular, bearing extended dorsal nob armed with 2 long stout spines; pereonites 1–5 with weak transverse dorsal depressions, pereonites 4–5 shortest of all, pereonites 6–7 exceptionally long, articulations between segments 5–7 and 6–7 incomplete, segments 6–7 heavily muscularized and rigid, pereonite 7 and pleonites 1–2 each with dorsal hump and occasionally weak dorsolateral accessory hump often marked only with setae; pleonal epimera almost evenly rounded below.

FEMALE.—Article 2 of gnathopod 2 lacking anteroventral process, distal cusp of article 4 small, article 6 stout, short, broadly ovate, palm long, strongly defined by 2 stout spines and weak cusp, palm minutely castellate; coxae broader than in male.

HOLOTYPE.—Bishop Museum collections, catalog number 7300, male, 2.6 mm.

TYPE-LOCALITY.—JLB Hawaii 5, off Ewa Beach, Oahu, 30 m, Pocillopora, 29 January 1967.

MATERIAL.—JLB Hawaii 2 (2), 5 (1), 12 (3), 13 (3), 17(1). Fee 1 (5).

RELATIONSHIP.—This subspecies differs from P. t. talegus J. L. Barnard (1965a) from Micronesia only in minor ways such as the rounder anteroventral cephalic margin, the shorter and broader article 5 of gnathopod 1, and apparently the slightly longer serrations on the dactyl of gnathopod 1. The terminal male of P. t. talegus is unknown.

Podocerus talegus seems to have close affinities with P. inconspicuus (Stebbing) and P. ?lobatus (Haswell) as identified by Pirlot (1938). There is considerable evidence that Pirlot’s materials should be given new or different names than those he applied. Unlike Pirlot’s species, P. talegus has a strong dorsal hump or keel only on 3 segments and the bulges are thick and not lamellar. A few individuals of those species identified by Pirlot also have only 3 segments keeled. Article 2 of gnathopod 2 on P. talegus lawai fits P. inconspicuus better than P. ?lobatus, but the palm of male gnathopod 2 fits P. ?lobatus better than P. inconspicuus. P. lobatus (Haswell, 1885) and P. ?lobatus of Pirlot have, however, a defining tooth on the palm, whereas, if that tooth is present on P. talegus, it has moved distally. Podocerus talegus does not fit the original P. inconspicuus (Stebbing, 1888) at all.

Poderus fulanus J. L. Barnard (1962a) from California (=Podocerus species of J. L. Barnard, 1959) has a few resemblances to P. talegus, but also has 4 keeled segments and has only 1 process on male gnathopod 2 palm, weaker ocular bulges, shorter posterior margin of pleonal epimeron 3, fewer spines on uropod 3, and a slightly shorter ventrodistal peduncular cusp on uropod 1, larger segment 6 of the pleon, and longer palm on gnathopod 1 than does P. talegus.

The so-called P. cristatus (Thomson) of California, as identified by J. L. Barnard (1962a), has 5 dorsally keeled segments and dorsolateral humps, but gnathopod 2 has only 2 palmar processes, 1 of them very thin, and article 2 of gnathopod 2 has a weak, mammilliform anteroventral lobe unlike that of P. talegus and the species of Pirlot; coxa 1 is less extended, epimeron 3 short posteriorly, the palm of gnathopod 1 is longer, lacks an anterodistal process on article 2 of gnathopod 2, and the cephalic lobes are sharp.

The Hawaiian specimens of P. talegus resemble Cyrtophium dentatum Haswell (1880a, p. 342) in dorsal keel. That species has been synonymized with P. cristatus. Chilton (1926) has drawings of an identification of P. cristatus from New Zealand (type-area) and P. talegus differs from those in the absence of a distinction between the thin palmar setae and 5–6 thick spines radiating around the defining corner of gnathopod 1 palm plus slight differences in the shape and arrangement of teeth on the palm of male gnathopod 2; Chilton does not show anterodistal lobes on article 2 of gnathopod 2.

Thomson’s (1881) second paper on Cyrtophium cristatum has a figure with a dorsal keel similar to several specimens of P. talegus with 4 weak dorsal humps, but the eyes of the New Zealand species appear weak, and he mentions 3–4 spines defining the palm of gnathopod 1.

Haswell’s (1885) Dexiocerella dentata (=Cyrtophium dentatum of 1880a) is shown to have uropods 1–2 similar to those of P. talegus, but both pairs have a ventral peduncular tooth instead of one as in P. talegus. Perhaps, that is an error.

The identity of Haswell’s Dexiocerella laevis by Walker (1904) (as Platophium laeve) seems to fit the Hawaiian species very closely. The palm of gnathopod 2 has no processes but that of young males in P. talegus also shows no processes from marginal view, and they might have been overlooked in Walker’s material. The fringing palmar setae of Walker’s material however, are very short whereas they are long in P. talegus. Walker’s material has similarities to P. talegus in dorsal ornamentation, telson, ocular lobe, gnathopod 1, the small proximal palmar acclivity on gnathopod 2, but coxa 1 is not as strongly extended forward, uropod 3 is less spinose, and the rami of uropods 1–2 are not clearly described as to length.

DISTRIBUTION.—Hawaiian Islands.