Owstonia geminata, 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 : 48-49

Owstonia geminata new species

( Figure 37 )

Owstonia sibogae . Endo et al., 2015:[7] and 2016:37 (misidentification of ASIZP 68128; comparative material, Philippines).

Holotype. MNHN-2016‒0021, 55 mm SL, Vanuatu, 15°7'58.8"S, 166°52'58.8"E, beam trawl in 191–248 m, Exped. MUSORSTOM 8, sta. 1118, 9 Oct. 1994.

Paratypes. 2 specimens, 68‒79 mm SL. MNHN 2001−3369 , (1, 68), same data as holotype ; ASIZP 68128 , (1, 79), Philippines, Luzon, Lamon Bay , 14°27'N, 121°48'E, beam trawl in 155‒160 m, Aurora sta. cp2719, Y.C. Liao and K.T. Shao, 29 May 2007.

Diagnosis. A species of Owstonia with LL pattern type 1; dorsal fin IV, 23‒24; anal fin I, 16−17; oblique body scale rows in mid-lateral series 29‒32; precaudal vertebra and anal-fin pterygiophores anterior to 1st haemal spine 13 and 5 respectively.

Description. (When counts vary, those of the holotype are given first, followed in parentheses by those of the two paratypes.) A species of Owstonia with LL pattern type 1, consisting of a simple lateral line that originates from the posttemporal sensory canal near anterodorsal margin of gill opening, curves upward and backward then continues posteriorly just below dorsal-fin base to soft rays 19 (19−22). Dorsal fin IV, 24 (23−24); anal fin I, 16 (I, 16‒17); pectoral fin 17/18 (17); gill rakers 14 (14‒16) + 27 (26−29) = 41 (40−44). Vertebrae: precaudal 13, caudal 17, total 30; anal-fin pterygiophores anterior to 1st haemal spine 5. Oblique body scale rows in mid-lateral series about 29/30 (ca. 31−32); nape scaly and cheek scale rows 3–4. Lower limb margin of preopercle with 10‒15 relatively large spines ( Fig. 8 C). Papillae in slight depression behind tip of premaxillary ascending processes 4, arranged in 2 closely spaced but distinct pairs. Teeth in outer row of each premaxilla 23 (22−31); no inner teeth anteriorly. Teeth in lateral row of each dentary 14 (14‒19), with mid-lateral teeth higher and slightly hooked backward, like those of O. fallax ; symphyseal teeth 2−3, bluntly conical (slightly larger than lateral teeth), and with 1 inner tooth anteriorly. Depressed pelvic fin short, extending only to anus. Caudal fin lanceolate. Caudal fin 2.2‒2.6 times in SL; head 3.3‒4.4 times in SL; body depth at anal-fin origin 4.5‒4.8 times in SL.

Color pattern in alcohol: dorsal fin uniformly pale; membrane connecting maxilla and premaxilla with prominent black stripe that extends about 2/3rd length of premaxilla, and inner membrane covering posterior part of dentary pale. Life coloration unknown.

Proportions of 55 mm SL holotype are given first, followed (in parentheses) by those of the 68 and 79 mm paratypes, as percentages of SL: predorsal length 27.0 (25.0−22.2); preanal length 50.4 (49.4−47.7); dorsal-fin base 66.2 (63.8−56.6); anal-fin base 40.2 (38.8−40.6); pelvic-fin length 22.2 (19.2−20.2); caudal-fin length 41.5 (38.5−46.1); body depth at anal-fin origin 22.2 (20.9−21.2); head length 30.4 (24.5−22.5); upper jaw length 13.1 (12.4−10.8); upper jaw depth 13.1 (5.4−5.0); orbit diameter 13.6 (11.0−10.0). As percentages of head length: upper jaw length 43.1 (50.6−47.9); orbit diameter 44.9 (44.9−44.6).

Comparisons. Owstonia geminata has most of the diagnostic characters of O. fallax but differs in having more oblique body scale rows in mid-lateral series 40‒42 (vs. 29−32) and pectoral-fin rays 20 (vs. 17 or 18), and a longer premaxillary stripe that extends entire length of premaxilla (vs. about 2/3 length of premaxilla). Owstonia hastata is the only other species that shares with O. geminata the same number of dorsal-fin spines, precaudal and caudal vertebrae, and anal-fin pterygiophores anterior to 1st haemal spine, but differs in having anal fin II, 14 (vs. I, 16−17), fin pelvic fin 34.4‒42% SL (vs. 19.2‒22.2% SL), and lower margin of preopercle with about 10−12 welldeveloped spines (vs. 10‒15 small spines). Owstonia sibogae is superficially similar to O. geminata but differs (with characters for O. geminata given in parentheses) as follows: anal fin II, 15−17 (vs. I, 16−17), precaudal vertebrae 12 (vs. 11), anal-fin pterygiophores anterior to 1st haemal spine 4 (vs. 5), and lower limb margin of preopercle with about 8−10 well-developed spines (vs. 10‒15 small spines). The Indian Ocean O. whiteheadi has a longer premaxillary stripe extending entire length of premaxilla (vs. only about 2/3 length of maxilla), more total gill rakers 52‒54 (vs. 40–44) and teeth on outer row of each premaxilla 39–45 (vs. 22–31), and fewer precaudal vertebrae and anal-fin pterygiophores anterior to 1st haemal spine 11 and 2 respectively (vs. 13 and 5).

Etymology. From the Latin geminatus (twin), in allusion to the obviously close phylogenetic relationship and superficial resemblance of this species to Owstonia fallax .

Distribution. ( Fig. 26 ) Known from Vanuatu and the Philippines from two trawl collections in depths of 191−248 and 155−160 m respectively.

Figures

FIGURE 8. Margins of preopercle lower limb (not drawn to scale), showing relative spine development in selected species of Owstonia: A, O. contodon, USNM 438013, 162 mm SL; B, O. elongata, USNM 432454, 110 mm SL; C, O. geminata, ASIZP 68128, 79 mm SL; D, O. maccullochi, holotype (right side reversed), AMS IA. 5815, 156 mm SL; E, O. maccullochi, NTM S. 11765 − 001, 146 mm SL; F, O. rhamma, holotype, MNHN 1995 – 0005, 102 mm SL; G, O. sarmiento, ANSP 165126, 82 mm SL; H., O. scottensis, CSIRO H. 7136 − 04, 103 mm SL; I, O. sibogae, ANSP 152035, 113 mm SL; J, O. taeniosoma, CAS 133928, 126 mm SL; K, O. tosaensis, ANSP 153169, 100 mm SL; L, O. weberi, ZMUC P. 531552, 127 mm SL.

FIGURE 26. Distributions of selected species of Owstonia based on specimens examined.

FIGURE 37. Owstonia geminata, holotype, MNHN- 2016 ‒ 0021, 55 mm SL, Vanuatu. Photograph by Sandra J. Raredon.