Owstonia doryptera (Fowler)

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 : 45-46

Owstonia doryptera (Fowler)

( Figure 34 )

Loxopseudochromis dorypterus Fowler, 1934a:354 , fig. 106 (original description; off northern Mindanao Island, R/V Albatross sta. D.5516; depth 175 fms [320 m]).

Material examined. 2 specimens, 56‒65 mm SL: USNM 93166 (64.8), here designated as lectotype of Loxopseudochromis dorypterus , Philippines, off northern Mindanao , Point Tagolo Light, 8°46'N, 123°32'30"E, 320 m, R/ V Albatross sta. D.5516, 9 Aug. 1909 ; USNM 410302 (56), paralectotype, same data as lectotype.

Diagnosis. A species of Owstonia with LL pattern type 3; cheek scale rows 5‒6; oblique body scale rows in mid-lateral series about 45; dorsal fin with interradial membranes between 2nd spine and 1st soft ray black distally.

Description. A species of Owstonia with LL pattern type 3, consisting of a lateral line that does not contact posttemporal sensory canal near anterodorsal margin of gill opening, but instead continues posteriorly just below dorsal-fin base and anteriorly beyond the dorsal-fin origin and makes a complete loop across nape; lateral line ends below dorsal-fin soft rays 15 (17), on right side only of lectotype and paralectotype respectively. Dorsal fin III, 21; anal fin I, 14; pectoral fin 21‒22; gill rakers 16 + 26‒28 = 42–44. Vertebrae: precaudal 11, caudal 17, total 28; analfin pterygiophores anterior to 1st haemal spine 2. Oblique body scale rows in mid-lateral series about 45; nape scaly and cheek scale rows 5‒6 ( Fig. 12 B). Lower limb margin of preopercle with about 12−14 very small, mostly skin-covered spines. Papillae in slight depression behind tip of premaxillary ascending processes 4, arranged in 2 almost equally spaced pairs, the posterior pair slightly larger ( Fig. 13 ). Dentition of lectotype in poor condition, description applies only to paralectotype. Teeth in outer row of each premaxilla 16/18, with 6‒9 anterior teeth spike-like; no inner teeth anteriorly. Teeth in lateral row of each dentary 9; symphyseal teeth 5 or 6, spike-like, and with 1 inner tooth anteriorly. Depressed pelvic fin extending to anal-fin origin in the lectotype. Caudal fin lanceolate. Caudal fin 2.4‒2.5 times in SL; head 2.8‒2.9 times in SL; body depth at anal-fin origin 3.6 times in SL

Color pattern in alcohol: Dorsal fin of lectotype with interradial membranes between 2nd spine and 1st soft ray black distally; this dark fin pigmentation is also shown in Flower’s (1943a, fig. 106) drawing of the specimen. Membrane connecting maxilla and premaxilla with prominent black stripe extending to near anterior end of premaxilla, and inner membrane covering posterior part of dentary also black. Life coloration unknown.

Proportions of 65 mm SL lectotype are given first, followed (in parentheses) by those of 56 mm paralectotype, as percentages of SL: predorsal length 30.7 (34.6); preanal length 59.4 (58.6); dorsal-fin base 62.3 (65.2); anal-fin base 30.4 (31.1); pelvic-fin length 25.7 (25.4); caudal-fin length 40.6 (42.5); body depth at anal-fin origin 27.6 (27.5); head length 34.9 (35.3); upper jaw length 19.3 (19.2); upper jaw depth 7.7 (8.2); orbit diameter 16.0 (17.3). As percentages of head length: upper jaw length 55.3 (54.3); orbit diameter 45.8 (48.9).

Comparisons. Owstonia rhamma and O. maccullochi are the only other species with LL pattern type 3 and scaly cheeks, but both have pale dorsal fins (at least in adults). Owstonia rhamma also agrees with O. doryptera in having very reduced preopercular spines but differs in having a lateral line with an incomplete nape loop (vs. nape loop complete in O. doryptera ), fewer cheek scale rows 3 (vs. 5–6) and several of the mid-lateral dentary teeth noticeably enlarged ( Fig. 69 ). Owstonia maccullochi typically has more dorsal- and anal-fin soft rays (see Table 4), 22 and 15 respectively (vs. 21 and 14 in O. doryptera ) and more oblique body scale rows in mid-lateral series 53‒54 (vs. 45).

Etymology. A combination of the Greek dory (spear) and pteron (fin), which according to Fowler (1934a) is "with reference to the long pointed soft vertical fins."

Distribution. ( Fig. 22 ) Known only from northern Mindanao, Philippines where trawled in 320 m. The two type specimens, both collected during the Albatross Expedition, are in poor condition. See Smith and Williams (1999) for history of the Albatross Philippine Expedition and its fishes.

Figures

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 13. Position of slight depression at posterodorsal tip of ascending premaxillary processes (dorsal view, anterior to right) containing four papillae outlined by box in Owstonia doryptera, paralectotype, USNM 410302, 56.3 mm SL.

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

FIGURE 34. Owstonia doryptera, lectotype, USNM 93166, 65 mm SL, Philippines, Mindanao. Photograph by Sandra J. Raredon.

FIGURE 69. Owstonia rhamma close-up of head of holotype to show large hooked dentary canines. Photograph by Sandra J. Raredon.