Oneirodes cristatus Regan & Trewavas 1932

Oneirodes cristatus (Regan & Trewavas, 1932)

Fig. 19

Dolopichthys cristatus Regan & Trewavas, 1932:67, fig. 93 (Banda Sea, ca. 2000 m). Oneirodes cristatus (Regan & Trewavas 1932): Pietsch, 1974:62. Pietsch, 2009:409.

Material. HUMZ 191422 (1, 52.7), st. 6, 8°37.3'S, 110°34.1'E – 8°37.4'S, 110°34.2'E, off Java, 810–830 m, 11 Sep. 2004.

Description. Dorsal-fin rays 6; pectoral-fin rays 15; anal-fin rays 4; caudal-fin rays 9. Vomerine teeth 4 (2, 2); upper jaw teeth 31; lower jaw teeth 31. Head length 36.6% SL; head depth 36.1; head width 16.9; illicial length 19.7; upper jaw length 26.4; lower jaw length 37.2.

Body short, fusiform, profile oval in lateral view. Mouth large, cleft slightly oblique. Illicium relatively short, its pterygiophore very long. Sphenotic and quadrate spines well developed.

Esca appendage pattern B of Pietsch (1974:34, fig. 60B): broad, laterally compressed, internally pigmented anterior appendage, with two compressed black-tipped papillae at distal margin, its total length shorter than esca; pair of small filamentous medial appendages, their total length about equal to esca; conical terminal papilla; and short compressed posterior appendage, pigmented distally.

Opercle bifurcated, length of upper fork 12.7% SL, lower fork 25.6% SL; ratio of lengths of upper and lower forks of opercle 0.49. Subopercle oval, length 5.3% SL, dorsal end short and broadly rounded, ventral end rounded.

Distribution. Previously only known from the type series collected in the Banda and Celebes seas. The Indonesian specimen represents the first record in the eastern Indian Ocean.

Remarks. Although the eastern Indian Ocean specimen is identified as O. cristatus, it has several differences: 2 black-tipped papillae are on the distal margin of the anterior escal appendage (vs. a scalloped distal margin); the medial appendages are considerable longer than the esca (vs. appendages shorter than esca); the posterior appendage simple (vs. appendage branched); and the species has 15 pectoral-fin rays (vs. 13–14). Because the species is only represented by a few specimens, it is difficult to judge whether these are intraspecific or interspecific differences.

The escal morphology is also similar to that of O. notius, a Southern Ocean species, but the species differs from the latter in having smaller ratio of lengths of upper and lower forks of opercle (0.49 vs. 0.52–0.59) and having fewer pectoral-fin rays (15 vs. 17–19).