Owstonia ainonaka, Smith-Vaniz, William F. & Johnson, David, 2016

Smith-Vaniz, William F. & Johnson, David, 2016, Hidden diversity in deep-water bandfishes: review of Owstonia with descriptions of twenty-one new species (Teleostei: Cepolidae: Owstoniinae), Zootaxa 4187 (1), pp. 1-103 : 35-40

Owstonia ainonaka new species

( Figure 28 )

Holotype. AMS I.33437‒002, 213 mm SL, Australia, NSW, off Coffs Harbour , 30°18'S, 153°26'E, 183 m, Tony Nyssen, 2 Sep. 1992.

Diagnosis. A species of Owstonia with LL pattern type 1; lower limb margin of preopercle without spines; all cheek scales abutting adjacent scales; dorsal fin III, 21; premaxillary stripe consisting of several, irregular, dark blotches; caudal fin lanceolate.

Description. A species of Owstonia with LL pattern type 1, consisting of a simple lateral line that originates from posttemporal canal near anterodorsal margin of gill opening, curves upward and backward then continues posteriorly just below dorsal-fin base to soft ray 18. Dorsal fin III, 21; anal fin I, 13; pectoral fin 22; gill rakers 15 + 26 or 27 = 41–42. Vertebrae: precaudal 11, caudal 17, total 28; anal-fin pterygiophores anterior to 1st haemal spine 2. Oblique body scale rows in mid-lateral series about 46/ 50 in addition to 4 scales on base of caudal fin; nape scaly and cheek scale rows 6‒7, with adjacent scales abutting each other ( Fig. 12 A). Lower limb margin of preopercle without spines. Papillae in slight depression behind tip of premaxillary ascending processes 4, arranged in 2 almost equally spaced pairs. When mouth closed upper jaw extends only to vertical from posterior margin of pupil. Teeth in outer row of premaxilla 19/22; 2/3 inner teeth anteriorly. Teeth in lateral row of each dentary 8/9, including at anterior end a row (left side) or irregular group (right side) of 4 blunt conical teeth as large as adjacent symphyseal teeth; symphyseal teeth 4 or 5, short and spike-like ( Fig. 9 A), and with 3 smaller inner teeth behind the anterior row or group of lateral teeth. Pelvic fin short, depressed fin does not extend to anus. Caudal fin lanceolate. Caudal fin 1.8 times in SL; head 3.3 times in SL; body depth at anal-fin origin 3.6 times in SL.

Color pattern in alcohol: Adults with dorsal fin uniformly pale; membrane connecting maxilla and premaxilla with irregular shaped, large, dark brown blotches ( Fig. 15 D), and inner membrane covering posterior part of dentary black. Life coloration unknown.

Proportional measurements of 213 mm SL holotype as percentages of SL: predorsal length 59.6; preanal length 28.5; dorsal-fin base 58.5; anal-fin base 63.4; pelvic-fin length 27.7; caudal-fin length 54.5; body depth at anal-fin origin 28.1; head length 30.7; upper jaw length 16.5; jaw depth 8.4; orbit diameter 11.4. As percentages of head length: upper jaw length 53.9; orbit diameter 38.3.

Comparisons. The allopatric O. kamoharai and O. crassa are the only two species that might be confused with this new species but differ (characters of O. ainonaka in parentheses) as follows: O. kamoharai has a caudal fin that is rounded posteriorly (vs. lanceolate) and shorter, 33.7‒40.0% SL (vs. 54.5%), smaller cheek scales many of which are slightly separated from adjacent scales (vs. larger scales that abut adjacent scales), and when mouth completely closed upper jaw usually extending to or slightly beyond vertical from posterior margin of orbit (vs. upper jaw extends only to vertical from posterior margin of pupil). Owstonia crassa has a continuous premaxillary stripe (vs. irregular dark blotches) and an upper jaw extending to or slightly beyond vertical from posterior margin of orbit (vs. upper jaw that extends only to vertical from posterior margin of pupil). Owstonia psilos resembles O. ainonaka in having a short pelvic fin that does not extend behind anus but differs in having the premaxillary stripe absent or pale and incomplete (vs. irregular dark blotches) and anal fin I, 14 (vs. I, 12‒13). Owstonia maccullochi superficially resembles O. ainonaka but differs most obviously in having LL pattern type 3 (vs. LL pattern type 1), lower limb margin of preopercle with spines (vs. preopercle without spines), anal fin I, 14‒16 (vs. I, 13), and continuous premaxillary stripe (vs. irregular dark blotches).

Distribution. ( Fig. 22 ) Known only from southeastern Australia where trawled in 183 m.

Etymology. A combination of the first (Ai) and last name (Nonaka) of the second author’s wife in appreciation for her valuable assistance with this study. The name is treated as a noun in apposition.

Figures

FIGURE 9. Frontal view of teeth in selected species of Owstonia (note widely spaced, spike-like, symphyseal, dentary teeth in C and D): A, O. ainonaka, AMS I. 33437 – 002, 213 mm SL; B, O. kamoharai, CSIRO 3596, 282 mm SL; C, O. psilos, NTM S. 12608 – 002, 75 mm SL; D, O. simotera, USNM 276514, 65 mm SL; E, O. simotera, SAIAB 605, 298 mm SL (photo by Ofer Gon, © SAIAB); F, O. weberi, ANSP 146627, 317 mm SL.

FIGURE 12. Cheek scales on left side in selected species of Owstonia: A, O. ainonaka, AMS I. 33437, 213 mm SL; B, O. doryptera, USNM 93166, 65 mm SL; C, O. elongata, MNHN 2008 – 1350, 110 mm SL; D, O. grammodon, USNM 93167, 67 mm SL; E, O. kamoharai, NTM S. 12631 – 017, 206 mm SL; F, O. kamoharai, CSIRO H. 2099 – 007, 408 mm SL; G, O. maccullochi, AMS I. 25806 ‒ 012, 141 mm SL; H, O. raredonae, SAIAB 82406, 97.4 mm SL; I, O. sibogae, CAS 33843, 126 mm SL.

FIGURE 15. Premaxillary stripes in selected species of Owstonia: A, O. hastata, NTM S. 11779 – 002, 124 mm SL; B, O. nudibucca, ANSP 151993, 224 mm SL, Mentawai Islands; C, O. sibogae, CAS 32914, 96 mm SL, Philippines; D, O. ainonaka, AMS I. 33437 – 002, 213 mm SL. Photographs by Sandra J. Raredon.

FIGURE 22. Distributions of selected species of Owstonia based on specimens examined.

FIGURE 28. Owstonia ainonaka, holotype, AMS I. 33437 ‒ 002, 213 mm SL, Australia, NSW off Coffs Harbour. Photograph by Sandra J. Raredon.