Lamprophaea aurita ( Hessle, 1925 ) Salazar-Vallejo, 2020

Salazar-Vallejo, Sergio I., 2020, Revision of Leocrates Kinberg, 1866 and Leocratides Ehlers, 1908 (Annelida, Errantia, Hesionidae), Zootaxa 4739 (1), pp. 1-114 : 29-31

Lamprophaea aurita ( Hessle, 1925) , n. comb., reinst.

Fig. 13

Leocrates auritus Hessle, 1925: 18–20 , Fig. 5 a–c.

Type material. Western Pacific. Japan. Holotype of Leocrates auritus Hessle, 1925 ( UUZM 626 ), Ogasawara, Chichi-jima (27°04’00” N, 142°12’30” E), coral, 25 Jul. 1914, S. Bock, coll.

Description. Holotype (UUZM 626) complete, slightly dehydrated along middle region, slightly bent ventrally. Body pale ( Fig. 13A ), obconic, slightly wider medially, blunt anteriorly, tapered posteriorly, 39 mm long, 4.5 mm wide (without parapodia), 16 chaetigers; right parapodium of chaetiger 9 previously removed, left parapodium of chaetiger 8 dissected (kept in container). Most tentacular, dorsal and ventral cirri intact. Body pale, eyes dark brown.

Prostomium as long as wide, slightly wider anteriorly. Lateral antennae with ceratophores well-defined, antennae about twice longer than prostomium, slightly longer than palps ( Fig. 13B ). Palpophores 3–4 times longer than palpostyles. Median antenna long, surpassing anterior prostomial margin, inserted centrally on prostomium, between eyes.

Eyes dark brown, anterior eyes about twice larger than posterior ones, slightly emarginate, more distant to each other than posterior round eyes ( Fig. 13B ).

Nuchal organs whitish, L-shaped, lateral lobes extended beyond lateral prostomial margins, lobes medially wider, not parallel-sided; lateral ciliated bands wide, clearly visible dorsally. Tentacular cirri mostly without tips, longer ones reach chaetiger 8. Lateral cushions low, entire, longitudinal striae visible.

Pharynx fully exposed, wider distally, without lateral vesicles. Anterior margin smooth, with irregular constrictions, better defined laterally ( Fig. 13C ). Dorsal jaw brownish, exposed, inserted below pharynx margin; ventral jaw smaller, exposed.

Dorsal cirri longer than body width, including parapodia ( Fig. 13D ), complete ones in middle segments half as long as body length. Chaetigers 1–3 without notochaetae; notochaetae present along chaetigers 4–16, about 60 per bundle, delicate, arranged in a transverse fan, notochaetae subdistally denticulate, denticles coarse ( Fig. 13E ). Notacicular lobes short, blunt, round ( Fig 13D , inset); neuracicular lobes blunt, projected, tips round, slightly longer than wide; aciculae black, tapered; ventral cirri surpass neurochaetal lobes. Neurochaetae about 30 per bundle, many blades missing, blades decreasing in size ventrally, bidentate, 6–9 times longer than wide, guards approaching subdistal tooth ( Fig. 13F ).

Posterior region tapered, with several dorsal and anal cirri on site. Pre-anal segment with dorsal cirri twice thicker than ventral one. Pygidium with anus terminal; anal cirri reach chaetiger 12–13.

Oocytes not seen.

Remarks. Hessle (1925:18) described Leocrates auritus . His description is complete and the illustrations are very good. However, the type of nuchal organs together with the presence of single fang-shaped, upper and lower jaws of the pharynx indicate it belongs to Lamprophaea and hence the new combination. Pettibone (1970: 213, 219), regarded L. aurita as a junior synonym of Leocrates giardi Gravier, 1900 , described from the Red Sea, but this nomenclatural act did not involve the study of types. Further, because the nuchal organs lobes in these two species are so different, they are herein regarded as different species, and belonging to different genera. Consequently, the synonymy must be rejected, and the species name is reinstated.

As indicated in the key above, L. aurita resembles L. ockeri n. sp. from the Hawaiian Archipelago because they have notochaetae from chaetiger 4, and anterior eyes round or slightly emarginate. They differ in the shape of prostomial and nuchal organs lobes. In L. aurita the posterior prostomial margins are straight, leaving some space from the posterior eyes, and lateral nuchal organs lobes are medially and distally swollen, whereas in L. ockeri the posterior prostomial margins are curved, leaving almost no space between its margins and posterior eyes, and the lateral nuchal organ branches have parallel sides.

Distribution. Only known from the Bonin Islands, Japan, in shallow-water, coralline substrates.

Figures

FIGURE 5. A. Dalhousia atlantica McIntosh, 1885, reinstated, non-type specimen (MNCN 10304), Banco de Galicia, pharynx dissected to show upper (left) and lower (right) jaws. B. Same, upper double jaw, most tissue removed. C. Same, lower transverse jaw, posterior view, note its complete longitudinal fusion. D. Paralamprophaea greeffiana (Augener, 1918) n. comb., non-type specimen (MNHN 372), upper jaw in posterior and lateral views (*: ligament). E. Same, lower jaw in anterior, lateral and posterior views. Scale bars: A: 0.24 mm, B: 0.22 mm, C: 0.27 mm, D: 0.18 mm, E: 0.14 mm.

FIGURE 13. Lamprophaea aurita (Hessle, 1925), new combination, reinstated, holotype (UUZM 626). A. Anterior region, dorsal view. B. Anterior end and pharynx everted, dorsal view. C. Pharynx, oblique ventral view, upper jaw visible. D. Chaetiger 8, left parapodium, anterior view (inset: notacicular lobe). E. Same, notochaetae distal regions. F. Three neurochaetal blades (insets: close-ups of two chaetal blade tips). Scale bars: A: 1.7 mm, B: 0.6 mm, C: 0.5 mm, D: 0.9 mm, E: 70 µm, F: 80 µm.