Owstonia weberi (Gilchrist)

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 : 93-95

Owstonia weberi (Gilchrist)

( Figures 84 , 85 )

Parasphenanthias weberi Gilchrist, 1922:69 , pl. 10, fig. 2 (original description; KwaZulu-Natal coast, South Africa; depth 183–190 fms [= 335‒374 m]).

Parasphenanthias microlepis Fowler, 1934b:462 , fig. 35 (original description; Durban, KwaZulu-Natal, South Africa). Owstonia weberi Smith-Vaniz, 1986:728 , color figs. pl. 112, fig. 226.3 & pl. 113, fig. 226.3 (brief description).

Material examined. 39 specimens, 45‒317 mm SL: South Africa SAIAB 11073 (ca. 81 SL, x-ray only), syntype of Parasphenanthias weberi , KwaZulu-Natal coast; ANSP 54940 (187), holotype of Parasphenanthias microlepis, Durban , Kwazulu-Natal, 335–374 m, H.W. Bell-Marley, 1932. Tanzania BMNH 1939.5 .24.1223 (1, ca. 180 SL, xray only) , Tanzania, John Murray Exped., 1933–1934 . Madagascar AMS I.28137‒003 (1, 139), LACM 44750‒10 (1, 128) , USNM 308024 (2, 120‒180) and ZMUC P.531552 (1, 127), NW of Tulear, 22°19'6"S, 43°6'6"E, 330‒335 m, R/V VITYAZ cruse 17 sta. 2644, 2 Dec. 1988; MNHN 1998‒845 (3, 72‒162), 17°16'58.8"S, 43°10'58.8"E, 540 m, sta. 73/108, FAO, 25 Sep., 1973; MNHN 2014–2933 (1, 45), 14°49'53"S, 46°59'9"E, trawled in 347–448 m, R/ V Miriky sta. 3248, 7 Jul. 2009; MNHN 2014–1257 (1, 48.5), 15°25'4"S, 46°0'16"E, beam trawl in 274–313 m, R/ V Miriky cruise, 3276, 12 Jul. 2009; MNHN 2014‒1286 (1, 112), 15°33"37"S, 45°42'5"E, beam trawl in 350–580 m, R/V Miriky, sta. 3267, 11 Jul. 2009. Kenya ANSP 146627 (1, 317), 3°4'S, 40°25'E, 280 m , PCH 80‒35, P.C. Heemstra, 17 Dec. 1980; SAIAB 13856 (18 spec., x-rays only) and USNM 410299 (2, 88‒118), off Malindi, 3°4'S, 40°25'E . Mozambique USNM 276515 (2, 71 & 110 C&S), 25°12'S, 34°4'E, 230‒295 m, R/ V Anton Bruun cruise. 8 sta. 397A , 29 Sep. 1964; SAIAB 11074 (2, x-rays only), Mozambique, P.1896.

Diagnosis. A species of Owstonia with a unique LL pattern 4; dorsal fin III, 20–22 (typically 21); anal fin I, 13–14; oblique body scale rows in mid-lateral series about 33–38; adults with teeth in outer row of each premaxilla 15‒21; adults with depressed pelvic fin extending to anal-fin soft rays 4‒9, depending on sex of specimen.

Description. A species of Owstonia with LL pattern 4, consisting of a lateral line that does not contact posttemporal sensory canal near anterodorsal margin of gill opening (although a diagonal row of 2–3 scales is typically present on its anterodorsal margin), continues posteriorly just below dorsal-fin base and anteriorly makes a complete loop across nape with a secondary loop on each side of primary loop ( Fig. 6 H); lateral line ends below dorsal-fin soft rays 20-21. Dorsal fin III, 20–22 (typically 21); anal fin I, 13–14; pectoral fin 19–21; gill rakers 16– 18 + 29–32 = 45–50. Vertebrae: precaudal 11, caudal 17 (exceptionally 16), total 28 (exceptionally 27); anal-fin pterygiophores anterior to 1st haemal spine 2. Oblique body scale rows in mid-lateral series about 33–38; nape scaly and cheek scale rows 2–3. Lower limb margin of preopercle with 6–12 moderate to strong spines ( Fig. 8 L). Papillae in slight depression behind tip of premaxillary ascending processes 4, arranged in 2 almost equally spaced pairs. Teeth in outer row of each premaxilla 15‒21, anterior ones spike-like; no inner teeth anteriorly. Teeth in lateral row of each dentary 12‒19; symphyseal teeth 4−5, relatively elongate and spike-like ( Figs. 9 F, 10L), and with 1‒2 inner teeth anteriorly. Pelvic fin sexually dimorphic in adults; depressed pelvic fin extending to soft rays 4‒5 (females) and to at least soft rays 8‒9 (males). Caudal fin lanceolate. In 12 specimens, 88‒317 mm SL, caudal fin 1.3‒2.4 times in SL; head 3.2‒4.0 times in SL; body depth at anal-fin origin 3.6‒4.2 times in SL.

Color pattern in alcohol: Adults and 48.5 mm specimen (MNHN 2014–1257) with anterior part of dorsal fin uniformly pale (except concentration of melanophores present distally between 2nd spine to at least 2nd soft ray in 45 mm specimen, MNHN 2014−2933), 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. In life, upper part of head and body red, changing to white below; dorsal, anal, pectoral and caudal fins red and pelvic fin white; iris red.

Proportions of 10 specimens 71‒317 mm SL mm SL, as percentages of SL: predorsal length 22.7‒27.8; preanal length 49.5‒57.9; dorsal-fin base 62.3‒66.6; anal-fin base 31.9‒34.0; pelvic-fin length 32.9‒54.4; caudalfin length 46.3‒78.0; body depth at anal-fin origin 18.7‒27.0; head length 25.2‒31.4; upper jaw length 13.6‒16.9; upper jaw depth 6.2‒10.9; orbit diameter 9.8‒16.9. As percentages of head length: upper jaw length 51.8‒57.5; orbit diameter 39.0‒54.9.

Comparisons. Owstonia weberi superficially resembles O. whiteheadi , but in addition to having a different lateral-line pattern, O. whiteheadi has more dorsal-fin spines IV (vs. III), anal-fin soft rays 1 5–16 (vs. 13–14) and teeth in outer row of each premaxilla 39–45 (vs. 15–21). Owstonia weberi differs from all its congeners that have a complete nape loop, none of which occur in the western Indian Ocean (characters of O. weberi in parentheses) as follows: Owstonia doryptera has very weak preopercular spines (vs. moderate to strong spines), and the holotype has interradial membranes of dorsal fin black between spine 2 and soft ray 1 (vs. dorsal fin with pale interradial membranes); O. totomiensis and O. nudibucca both have naked cheeks (vs. scaly cheeks); and O. sarmiento has a lateral line with a vertical section connecting posttemporal sensory canal near anterodorsal margin of gill opening to horizontal section below dorsal fin (vs. no vertical section), dorsal fin III, 23–24 (vs. III, 2 0–22, usually 21), and anal fin II, 14 (vs. I, 13–14).

Etymology. Named for Max Wilhelm Carl Weber (1852‒1937), who is best known for his work on Siboga Expedition fishes and mammals. He was educated in Germany, later became a Dutch citizen and one of the most influential Dutch zoologists of his time; see Adler (2012:144‒145) for a brief biography with emphasis on Weber's herpetological contributions, and other biographical reference sources.

Distribution. ( Fig. 27 ) Western Indian Ocean from South Africa to Kenya and Madagascar where trawled in 274‒ 540 m.

Figures

FIGURE 6. Diagrammatic illustrations of lateral-line patterns in selected species of owstonia: type 1 pattern: A (O. japonica); type 2 pattern: B, F (O. tosaensis), E (O. sarmiento); type 3 pattern: C, G (O. maccullochi), D (O. nudibucca); type 4 pattern: H (O. weberi). See text for detailed discussion of these patterns in owstoniines.

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

FIGURE 84. Owstonia weberi, SAIAB 13856, 252 mm SL, Kenya, off Malinda. Photograph by Phillip C. Heemstra, © SAIAB.

FIGURE 85. Owstonia weberi, SAIAB 81897, 125 mm SL, off Mozambique. Photograph by Oddgeir Alvheim.