Dieidolycus adocetus

description

Description. The 2 specimens are damaged juveniles, with the skin torn away and, in the paratype, the tail tip missing and gill slits ripped. Head pore patterns cannot be determined. Counts and measurements are those of the holotype, paratype in parentheses. Vertebrae 23 + 56 = 79 (23 + 40 +); D 72; A 55; C 8; P 13 (13); pelvics 2 (2), gill rakers 2 + 12 (2 + 10); pyloric caeca 2 (2); branchiostegal rays 6 (6); vomerine teeth 7 (4); palatine teeth 3 - 4 (3 - 4); pseudobranch absent. Following measurements in percent SL: predorsal length 26.1; preanal length 47.3; prepelvic length 16.7; body depth 8.0; pectoral length 12.6; pectoral base height 4.7; head length 22.5; head width 8.9, head depth 9.1; gill slit length 404. Following measurements in percent HL: head width 3904 (37.6); head depth 4004 (37.6); pectoral length 56.1 (60.2); pelvic length 19.2 (17.7); upper jaw length 37.9 (34.5); snout length 15.7 (13.8); eye diameter 11.1 (10.5); orbit diameter 27.8 (27.6); gill slit length 19.7; interorbital width 7.6 (8.3); interpupillary width 19.2 (2004). Head triangular, dorsal profile gently inclined anteriorly; nape flattened. Head large and robust, snout short and broad. Eye small,

Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. VII. A new species of Dieidolycus Anderson, 1988 from the Bismarck Sea

diagnosis

Comparisons. Because of the damage to the new specimens, the thought that they might represent a new species of the monotypic Taranetzella Andriashev, 1952 was at first considered. Taranetzella differs from Dieidolycus in possessing scales, nine preoperculomandibular pores, and low papillae between the mandibular and suborbital pores. None of these characters could be verified in the new specimens. However, they also differ from Taranetzella in their significantly different vertebral counts (19 - 20 + 70 - 78 in Taranetzella), six suborbital bones (8 in Taranetzella), two pelvic rays (3 in Taranetzella) and lack of a pseudobranch. Other important characters the new species shares with its congener, D. leptodermatus Anderson, 1988, are a greatly reduced oral valve, small eyes and restricted gill slit (the latter also the condition in Taranetzella).

Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. VII. A new species of Dieidolycus Anderson, 1988 from the Bismarck Sea

diagnosis

Diagnosis. A species of Dieidolycus as defined by Anderson (1988) with P 13; first dorsal-fin pterygiophore associated with vertebrae 5 - 6.

Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. VII. A new species of Dieidolycus Anderson, 1988 from the Bismarck Sea

discussion

Remarks. The finding of specimens of Zoarcidae under tropical seas is of great interest since these fishes are primarily found III the cold waters of high latitudes (Anderson, 1984). However " tropical " an influence the waters of lower latitudes has on the distribution of shore fishes, temperatures at the great depths that tropical zoarcids encounter are within the realm of temperatures found in other areas they inhabit. Thus, tropical slope areas are not well demarcated zoogeographic barriers to this family, and many species are now known to range through both temperate and tropical regions (4 species each of Lycodapus Gilbert, 1890 and Melanostigma Giinther, 1881 and three species of Pachycara Zugmayer, 1911 [Anderson, 1989 a, 1989 b, 1990]). Vaillant (1888) reported the first zoarcids (Pachycara crassiceps [Roule, 1916]; see Anderson, 1989 a) from tropical slope waters from the 1883 eastern Atlantic cruise of the Talisman, recording a temperature of 4.5 ° C at their maximum capture depth of 1493 m. Garman (1899) reported the second occurrence of zoarcids from tropical seas, these from the 1891 Albatross cruise in the eastern Pacific. Twelve nominal species were found between 83

Studies on the Zoarcidae (Teleostei: Perciformes) of the southern hemisphere. VII. A new species of Dieidolycus Anderson, 1988 from the Bismarck Sea