Revision of the circumglobal deep-sea genus Leucicorus (Teleostei, Ophidiidae) with two new species Author Schwarzhans, Werner W. Zoological Museum, Natural History Museum of Denmark, Universitetsparken 15, 2100 Copenhagen Ø, Denmark and Ahrensburger Weg 103, 22359 Hamburg, Germany Author Nielsen, Jørgen G. Zoological Museum, Natural History Museum of Denmark, Universitetsparken 15, 2100 Copenhagen Ø, Denmark. jgnielsen @ snm. ku. dk Author Mundy, Bruce C. Ocean Research Explorations, P. O. Box 235926, Honolulu, HI 96823, USA. mundyichthyo @ gmail. com text Zootaxa 2022 2022-02-22 5100 4 541 558 journal article 20509 10.11646/zootaxa.5100.4.5 88055c49-f6af-41f7-9672-96d9572b7639 1175-5326 6224876 8DD15BEE-86E0-4DD8-AC05-6C76A993508C Leucicorus lusciosus Garman, 1899 Table 1 , Figs. 1D–E , 2A , 3J–K , 5 Leucicorus lusciosus Garman, 1899: 146 . Leucicorus lusciosus : Grey 1956: 218 ; Nielsen 1975: 109 . Material examined ( 2 specimens , SL 225–245 mm and a radiograph of SIO 81–148 ) . Holotype : MCZ 28680 , 245 mm SL, male, eastern tropical Pacific , 14 ° 46’N , 98°40’W , R / V Albatross , st. 3415, beam trawl, 3436 m , 10 Apr. 1891 . Non-types : ZMUC P 771814, 225 mm SL, female, off Peru , 17°42’S , 78°59’W , R / V Akademik Kurchatov , st. 271, Sigsbee trawl, 2710–3080 m , 20 Dec. 1968 . Radiograph and otolith of SIO 81–148 , 251 + mm SL, female, Panama Basin , 5.175°N , 81°68’W , R / V Melville , 40’ otter trawl, PA 3, 3900–4000 m , 31 Mar. 1931 . Diagnosis. Dorsal-fin rays 110–114 and anal-fin rays 87–99; total vertebrae 68–69. Extensive squamation on opercle, preopercle and occiput; 35 to 40 transversal scale rows on trunk above beginning of anal fin. Otolith elongate (OL:OH = 1.65–1.75), with inner face more strongly convex than outer face. Comparison. L. lusciosus is most similar to L. gerringerae , due to the extensive squamation on head; however, it differs from L. gerringerae by having more dorsal- (110–114 vs. 97) and anal-fin (96–99 vs. 73–80) rays, smaller scales on head (~ 1 mm vs 2.0– 2.5 mm ) and more scale rows on trunk above anal-fin origin (35–40 vs. 24–25). It differs from both L. atlanticus and L. lentibus by the extensive head squamation and a high number of transversal scale rows above origin of anal fin. Description. The principal meristic and morphometric characters are shown in Table 1 . Body elongate and compressed with tapering tail; head broad with dorsal profile straight except for a slight concavity above eyes; head bones thin and fragile. Anterior nostril placed midway between upper lip and posterior nostril and the larger posterior nostril close to orbit. Orbit equal in length of snout; lens poorly developed or absent. Opercular spine thin and pointed. Body fully scaled, head with scales on opercle, preopercle and occiput. Pelvic fins each with two tightly joined rays. Pectoral fins placed on midbody. Mouth terminal; upper jaw ends below posterior edge of orbit; supramaxilla well developed. Anterior gill arch with 9–10 long developed and eight knob-like rakers. 1–2 pseudobranchial filaments. Otolith ( Fig 3J–K ). Large otoliths up to 11.4 mm in length with slender, droplet-like shape (OL:OH = 1.65– 1.75). Ventral rim shallow; dorsal rim higher, broadly rounded, with obtuse pre- to mediodorsal angle; anterior rim broadly rounded; posterior tip slightly tapering. Inner face convex, outer face flat to slightly convex; otolith height: thickness = 2.0–2.6. Sulcus straight, shallow, narrow, with single well-defined colliculum; otolith length: sulcus length = 1.80–1.9; sulcus length: height = 3.6–4.3. Sulcus not connected to anterior-dorsal rim. Ventral furrow well expressed, close to ventral otolith rim; indistinct dorsal depression. Distribution ( Fig. 5 ). Known from three localities in the East Pacific Ocean. Caught in bottom trawls at 2710– 4000 meters. Leucicorus lusciosus is the only species in the genus caught at bathyal depth. Two sightings by ROV from the NOAA ship Okeanos Explorer campaign south of Hawaii and near the southern Line Islands may also belong to L. lusciosus (see below).