Owstonia fallax, 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 : 47-48

Owstonia fallax new species

( Figure 36 )

Holotype. CSIRO H.763‒06, 110 mm SL male, Queensland, Australia, NE Hinchinbrook Island , 17°49'S, 146°51'E, 170 m, sta. SOO685/55, 1 Dec. 1985.

Other material. 1 specimen, 96 mm SL: New Caledonia USNM 276516 (1, 96), Noumea, off barrier reef taken from stomach of tilefish, Branchiostegus wardi , 250 m, P. Fourmanoir, 2 Apr. 1974.

Diagnosis. A species of Owstonia with LL pattern type 1; dorsal fin IV, 22‒23; anal fin I, 16; oblique body scale rows in mid-lateral series 40‒42; 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 New Caledonia specimen.) A species of Owstonia with LL pattern type 1, consisting of a simple lateral line that originates from the posttemporal sensory canal near the anterodorsal margin of gill opening, curves upward and backward then continues posteriorly just below dorsal-fin base to soft rays 20 (22). Dorsal fin IV, 22 (23); anal fin I, 16; pectoral fin 20; gill rakers 16 (15/16) + 29 = 45 (44/45). 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 42 (ca. 40); nape scaly and cheek scale rows 3–4. Lower limb margin of preopercle with small spines. 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 32/31 (34/34); no inner teeth anteriorly. Teeth in lateral row of each dentary 17 (16/19), including 3 at anterior end that continue in a row behind symphyseal teeth and with mid-lateral teeth longer and hooked backward ( Fig. 10 B), like those of O. geminata ; symphyseal teeth 6 (6), short and conical, larger than lateral teeth, and with cluster of 4 inner teeth anteriorly. Pelvic fin length possibly sexually dimorphic in length, depressed fin extending to anterior margin of anus in holotype and almost to anal-fin origin in paratype. Caudal fin lanceolate. In holotype followed by paratype, caudal fin 1.8, 2.6 times in SL; head 4.5, 4.6 times in SL; body depth at anal-fin origin 5.0, 5.7 times in SL.

Color pattern in alcohol: dorsal fin uniformly pale; membrane connecting maxilla and premaxilla with prominent black stripe extending to near anterior end of premaxilla, and inner membrane covering posterior part of dentary pale in holotype and dark in other specimen. In a note with the New Caledonia specimen, Fourmanoir recorded the life coloration as “body pink, eyes yellow, supraorbital rim blue.”

Proportions of 110 mm SL holotype are given first, followed (in parentheses) by those of the 96 mm specimen, as percentages of SL: predorsal length 20.8 (19.7); preanal length 45.1 (41.7); dorsal-fin base 68.2 (70.5); anal-fin base 44.0 (42.6); pelvic-fin length 17.6 (18.5); caudal-fin length 54.4 (38.6); body depth at anal-fin origin 20.2 (17.5); head length 22.4 (21.9); upper jaw length 10.8 (10.3); upper jaw depth 4.3 (4.8); orbit diameter 8.3 (9.0). As percentages of head length: upper jaw length 48.3 (47.1); orbit diameter 36.8 (41.0).

Comparisons. Owstonia fallax has most of the diagnostic characters of O. geminata but differs in having fewer oblique body scale rows in mid-lateral series 29−32 (vs. 40‒42), pectoral-fin rays 17 or 18 (vs. 20), and a shorter premaxillary stripe extending about 2/3 length of premaxilla (vs. entire length of premaxilla). Owstonia hastata is superficially most similar to O. fallax but differs (with characters for O. fallax given in parentheses) as follows: anal fin II, 14 (vs. I, 16), pelvic fin 34.4‒42% SL (vs. 17.6‒18.5%), and lower limb margin of preopercle with about 11 or 12 well-developed spines (vs. small weak spines). Owstonia sibogae is also superficially similar to O. fallax but differs as follows: anal fin II, 15−17 (vs. I, 16), 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 welldeveloped spines (vs. 10‒15 small spines). Other species with LL pattern type 1 and IV dorsal-fin spines differ in having anal fin II, 14–17 or I, 17–19 (vs. I, 16), except anal fin I, 15–16 in the Indian Ocean O. whiteheadi which has more total gill rakers 52‒54 (vs. 40–45), teeth in outer row of each premaxilla 39–45 (vs. 31–34), and fewer precaudal vertebrae and anal-fin pterygiophores anterior to 1st haemal spine 11 and 2 respectively (vs. 13 and 5).

Etymology. The specific epithet is from the Latin fallax (deceitful, false), in reference to its superficial resemblance to Owstonia hastata .

Distribution. ( Fig. 26 ) Known from Queensland, Australia and New Caledonia in depths of 170 and 250 m.

Remarks. The New Caledonia specimen has a much shorter caudal fin than the holotype and also differs in having the inner membrane covering the posterior part of the dentary very dark (pale in holotype) ; with only single specimens from each locality, we are not certain that both specimens are conspecific and therefore do not designate the New Caledonia specimen as a paratype .

Figures

FIGURE 10. Premaxilla and dentary (mostly right side reversed) to show dentition in selected species of Owstonia. A, O. contodon, USNM 438013, 162 mm SL; B, O. fallax, CSIRO H. 763 ‒ 06, holotype, 110 mm SL; C, O. grammodon, USNM 149321, 127 mm SL; D, O. hawaiiensis, BPBM 29600, holotype, 124 mm SL; E, O. ignota, USNM 344400, holotype, 118 mm SL; F, O. japonica, ANSP 151948, 136 mm SL.

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

FIGURE 36. Owstonia fallax, holotype, CSIRO H 763 ‒ 06, 110 mm SL, male, Queensland, Australia. Photograph by Sandra J. Raredon.