Owstonia raredonae, 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 : 76-77

Owstonia raredonae new species

( Figure 67 )

Holotype. SAIAB 82406, 97 mm SL, off Mozambique, 18°50.7'S, 37°13.5'E, 311‒314 m; P. C. Heemstra; 29 Oct. 2007.

Diagnosis. A species of Owstonia with LL pattern type 1; dorsal-fin rays III, 19; anal-fin rays I, 12; lower margin of preopercle smooth; oblique body scale rows in mid-lateral series about 31–32.

Description. 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 17/18. Dorsal fin III, 19; anal fin I, 12; pectoral fin 18; gill rakers 14+24 or 25. Vertebrae: precaudal 11, caudal 16, total 27; anal-fin pterygiophores anterior to 1st haemal spine 3. Oblique body scale rows in mid-lateral series about 31–32; nape scaly and cheek scale rows 3–4 ( Fig. 12 H). Preopercle lower limb margin without spines. Papillae in slight depression behind tip of premaxillary ascending processes 4, arranged in 2 pairs, with the posterior pair bluntly rounded and the other two smaller and tapered. Teeth in outer row of each premaxilla 35; 2 slightly larger, hooked, inner teeth anteriorly. Teeth in lateral row of each dentary 19/20; symphyseal teeth 4, relatively short and bluntly conical, and with 1 inner tooth anteriorly. Depressed pelvic fin extending to slightly behind anal-fin origin. Caudal fin lanceolate. Caudal fin 2.5 times in SL; head 3.1 times in SL; body depth at anal-fin origin 3.5 times in SL.

Color pattern in alcohol: Adults with dorsal fin uniformly pale; membrane connecting maxilla and premaxilla with prominent black stripe extending to near end premaxilla, and inner membrane covering posterior part of dentary also black. In life, dorsal, caudal and pectoral fins mostly red; distal half of anal fin reddish, the rest of fin colorless, as is most of pelvic fin; head and body reddish becoming paler below with belly and chest mostly white.

Proportions of 97 mm SL holotype as percentages of SL: predorsal length 32.3; preanal length 56.8; dorsal-fin base 61.7; anal-fin base 30.9; pelvic-fin length 25.7; caudal-fin length 40.5; body depth at anal-fin origin 28.4; head length 32.6; upper jaw length 17.2; upper jaw depth 8.6; orbit diameter 15.4. As percentages of head length: upper jaw length 53.0; orbit diameter 47.3.

Comparisons. Other species with LL pattern type 1 differ (characters of O. raredonae in parentheses) in having dorsal-fin rays III, 20–26 or IV, 21–26 (vs. III, 19) and anal-fin rays either I, 13–18 (except I, 11 in O. merensis and I, 12 in 1 of 6 Hawaiian small individuals tentatively identified as O. hawaiiensis ) or II, 11–16 (vs. I, 12). Owstonia raredonae further differs from other western Indian Ocean species as follows: O. weberi and O. whiteheadi both have lower limb margin of preopercle with moderate to strong spines (vs. smooth preopercle margin), O. similis has oblique body scale rows in mid-lateral series 52–56 (vs. 31–32) and total gill rakers 32–33 (vs. 36–40); O. simotera has more cheek scale rows, 11–12 (vs. 3–4) and O. lepiota has more oblique body scale rows in mid-lateral series, 95 (vs. 31–32) and nape naked (vs. nape scaly).

Etymology. Named for Sandra J. Raredon, Smithsonian Institution, in appreciation of her expertise with digital radiographs and photographs, which has contributed significantly to this monograph.

Distribution. ( Fig. 27 ) Known only from the type locality off Mozambique, where trawled in 311‒ 314 m.

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 27. Distributions of selected species of Owstonia based on specimens examined.

FIGURE 67. Owstonia raredonae, holotype, SAIAB 82406, 97 mm SL, off Mozambique. Photograph by P. C. Heemstra, © SAIAB.