Leocrates reishi, 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 : 66-68

Leocrates reishi n. sp.

Figs 36 , 37

urn:lsid:zoobank.org:act:B9292D1D-04DA-41A6-B4BA-D28B5FE34270

Leocrates chinensis: Hartman 1954: 622 (Bikini and Eniwetok atolls), 625 (outside Bikini atoll, Lidilbut Island, Eniwetok atoll), 628 (systematic list); Reish 1968: 213; Pettibone 1970: 215 (listed specimen; not described nor illustrated); Bailey-Brock & Hartman 1987: 262–263, Fig. 3 .II.33 (all partim, non Kinberg, 1866).

Type material. Western Pacific. Marshall Islands. Holotype ( LACM 10883 ), Ralik Chain , Eniwetok Atoll, Lidilbut Island, corals, Sta. 1504 (no further data), May 1952, H.S. Ladd, coll. Paratype ( LACM 10884 ), Ralik Chain , Eniwetok Atoll, Lidilbut Island, corals, Sta. 1503 (no further data), May 1952, H.S. Ladd, coll. [complete. Brownish, posterior region bent dorsally, most notochaetae and cirri missing; a lateral ventral dissection made to observe pharynx jaws; right parapodium of chaetiger 12 dissected (kept in container). Body 19 mm long, 2 mm wide, 16 chaetigers. Anterior eyes emarginate, twice larger than posterior round ones. Notochaetae with coarse subdistal denticulation; notacicular lobe blunt, neuracicular lobe round, about as long as wide; neurochaetae with blades bidentate, guard approaching subdistal tooth. Oocytes not seen; testis with spermatids in parapodia] .

Additional material. Western Pacific. Philippines. One specimen ( LACM 10142 ), Palawan, Honda Bay (09°54’02.5200” N, 118°43’21.3600” E), seagrass bed, under coral rubble, 1.2 m, 18 Apr. 1995, K. Fitzhugh, coll. [middle 17 mm long, 2 mm wide] . New Caledonia. One specimen ( UF 4016 ), Poum Pass (20°16’22.44” S, 163°52’48.72” W), back reef, patch coral, 0–2 m, 12 Nov. 2013, N. Evans, coll. [18 mm long, 2 mm wide] .

French Polynesia. One specimen ( UF 1433 ), Society Islands , Moorea, Atiha Bay, west side of pass (17°35’44.52” S, 149°50’44.16” W), barrier reef, 0.5–1.0 m, 8 Dec. 2009, S. McPherson & G. Paulay, coll. [16 mm long, 2 mm wide] .

Description. Holotype (LACM 10883) complete, slightly bent ventrally. Body with parallel sides ( Fig. 36A ), blunt anteriorly, slightly tapered posteriorly, 20 mm long, 3 mm wide, 16 chaetigers; right parapodium of chaetiger 7 dissected (kept in container). Most tentacular, dorsal and ventral cirri on site. Body brownish, cirri paler, eyes brown.

Prostomium wider than long, slightly wider anteriorly ( Fig. 36B ). Lateral antennae with ceratophores distinct, antennae slightly longer than prostomium (1.2 times as long), 1.2–1.5 times longer than palps; palpophores 2–3 times longer than palpostyles (palpostyles darker along basal half). Median antenna short, surpassing prostomial centre, not reaching prostomial anterior margin, inserted between posterior eyes.

Eyes dark brown, right eyes darker; anterior eyes each 1 / 15 prostomial width, twice larger than posterior ones, slightly emarginate anterolaterally, and more distant to each other than posterior, round eyes.

Nuchal organs lobes horizontal C-shaped, completely concealed by anterior margin of tentacular belt; lateral ciliated bands narrow, not visible dorsally. Tentacular cirri almost complete, twisted, without tips, longer ones reaching chaetiger 7. Lateral cushions low, entire, slightly projected along middle chaetigers. Longitudinal striae visible along body.

Pharynx fully exposed ( Fig. 36C ), slightly expanded distally. Lateral vesicles present only on right side, globular, not tapered. Anterior margin with about 30 irregularly defined lobes. Dorsal and ventral jaws single, brownish, exposed, tapered, ventral jaw smaller than dorsal one.

Dorsal cirri as long as body width (including parapodia). Chaetigers 1–4 without notochaetae; notochaetae present along chaetigers 5–16, sparse (about 30 per bundle), delicate (some parapodia with notochaetae broken), some arranged as transverse fans, notochaetae subdistally denticulate, denticles coarse (visible in 10x). Notacicular lobes blunt, neuracicular lobes projected, blunt, as long as wide ( Fig. 36D ). Neurochaetae about 20 per bundle, blades decreasing in size ventrally, bidentate, 3–12 times longer than wide, guards approaching subdistal tooth ( Fig. 36D , insets).

Posterior region tapered. Prepygidial segment with dorsal cirri 3–4 times longer than ventral ones. Pygidium not projected, anus dorsoterminal, anal cirri missing.

Oocytes not seen.

Etymology. This species is named after the late Dr. Donald J. Reish in recognition of his many publications on several critical localities (including San Quintín and Los Angeles bays in Western Mexico), and especially after his study on the polychaetes from the Marshall Islands ( Reish 1968). He made two field trips to the islands and a compilation of all recorded species, and his objective was very important because he tried to prepare a reference collection for the marine lab there (now the Mid-Pacific Marine Lab, University of Hawaii). The species-group name is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Variation. The paratype ( Fig. 37A, B ) has an unusual development of the nuchal organs, because they are completely exposed and projected posteriorly, which differs from the holotype and other additional specimens ( Fig. 37D, E ) where the nuchal organs are barely projected posteriorly. Parapodial features do not differ at all ( Fig. 37C, F ), as well as other prostomial sensors like palps, antennae and eyes. This explains why they are regarded as conspecific despite the difference in the development of the nuchal organs lobes. An alternative would be to regard this species as belonging in Paradalhousia n. gen. but its species have very large eyes and notochaetae are usually abundant, and these features are not present in the paratype.

Remarks. Leocrates reishi n. sp. belongs in the group having small eyes, with anterior eyes twice larger than posterior ones, together with L. ahlfeldae n. sp. from India, L. chinensis Kinberg, 1866 from Hong Kong, and L. giardi Gravier, 1900 from the Red Sea. However, L. reishi is the only species with notacicular lobes blunt (all others have tapered lobes), and with scarce neurochaetae, 15–20 per bundle; L. giardi has scarce neurochaetae but its notacicular lobes are tapered.

Distribution. Marshall Islands, the Philippines, New Caledonia and the French Polynesia, in coralline substrates, in 1–2 m depth.

Figures

FIGURE 3. Lamprophaea longicirrata (Treadwell, 1902), new combination, non-type specimens, Florida (ECOSUR 3075), prostomia, dorsal view. A. Smallest specimen, 13x2 mm. B. Medium-sized specimen, 32x3.5 mm. C. Large specimen, pharynx slightly exposed, 32x4 mm. D. Small specimen, pharynx exposed, 20x3 mm. Scale bars: A: 0.25 mm, B–C: 0.4 mm, D: 0.30 mm.

FIGURE 36. Leocrates reishi n. sp., holotype (LACM 10883). A. Dorsal view, middle depression and shine due to glass slide. B. Anterior end, dorsal view. C. Pharynx, frontal view. D) Chaetiger 7, right parapodium, anterior view (insets: notacicular lobe, lower and upper neurochaetal blades). Scale bars: A: 1.8 mm, B: 0.7 mm, C: 0.6 mm, D: 0.4 mm.

FIGURE 37. Leocrates reishi n. sp. A. Paratype (LACM 10884), anterior region, dorsal view. B. Same, anterior end, dorsal view, MGS. C. Same, chaetiger 12, right parapodium, anterior view, MGS. D. Additional specimen (LACM 10142), anterior region, dorsal view. E. Same, anterior end, dorsal view, MGS. F. Same, chaetiger 11, right parapodium, anterior view. Scale bars: A: 0.8 mm, B, F: 0.4 mm, C: 0.3 mm, D: 1.4 mm, E: 0.5 mm.