Owstonia grammodon (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 : 50-51

Owstonia grammodon (Fowler)

( Figure 38 )

Opsipseudochromis grammodon Fowler, 1934a:357 , fig. 107 (original description; type locality erroneously given as "between Gillolo and Kayoa islands", but see Remarks).

Owstonia grammodon (non Fowler). Okada and Suzuki, 1956:185, fig. 1 (osteology; based on misidentification of O. japonica ); Endo et al., 2015:[7] and 2016:37 (comparative material two specimens, 102‒116 mm SL from Taiwan).

Material examined. 5 specimens, 51‒127 mm SL. Sulawesi : USNM 93167 (67), holotype of Opispseudochromis grammodon , Sulawesi, Doworra Islands , 0°50'S, 128°12'E, 375 m, R/ V Albatross sta. D.5629, 2 Dec. 1909 ; USNM 149321 (1, 127) and USNM 151389 (1, 51), same data as holotype. Taiwan : ASIZP 59004 (1, 102) Nanfang-ao Yilan, 24.5818°N, 121.8668°E, B.H. Gao, 1 Jul. 1993 ; ASIZP 64630 (1,115.6), Da-xi , Yilan, 24.94°N, 121.9°E, fish market, K.- T. Shao, 27 Jun. 2004 .

Diagnosis. A species of Owstonia with LL pattern type 1; lower limb margin of preopercle without spines; dorsal fin III, 2 0–22; anal fin I, 13; dorsal fin without black blotch anteriorly in adults; black premaxillary stripe; adults with 33–39 teeth in outer row of each premaxilla.

Description. A species of Owstonia with LL pattern type 1, conisting of a simple lateral line that originates from posttemporal sensory canal near anterodorsal margin of gill opening, curves upward and backward then continues posteriorly just below dorsal-fin base to soft rays 19‒22. Dorsal fin III, 20–22; anal fin I, 13; pectoral fin 19; gill rakers 11+25 (in 67 SL holotype), 13/14+26/27 = 40 (in largest 127 SL specimen) and 13+22–23 = 35‒36 (in 102–116 SL Taiwan specimens). Vertebrae (values for Taiwan specimens in parentheses): precaudal 11 (12), caudal 17 (16), total 28; anal-fin pterygiophores anterior to 1st haemal spine 3 (4). Oblique body scale rows in midlateral series 40‒45; nape scaly and cheek scale rows 5‒6 ( Fig. 12 D). Lower limb margin of preopercle without spines. Papillae in slight depression behind tip of premaxillary ascending processes 4, arranged in 2 almost equallyspaced pairs. Teeth in outer row of each premaxilla of holotype ca. 38 (33‒39); 1 or 2 inner teeth anteriorly. Teeth in lateral row of each dentary in holotype ca. 17 (15‒18), the mid-lateral teeth relatively large and slightly hooked backward; symphyseal teeth 3 or 4, relatively large and conical ( Fig. 10 C), and with 2 (2‒4) inner teeth anteriorly. Depressed pelvic fin extending to anal-fin origin in largest (unsexed) Philippine specimen and in Taiwan specimens. Caudal fin lanceolate.

Color pattern in alcohol: Dorsal fin uniformly pale; membrane connecting maxilla and premaxilla with evidence of dark stripe extending to near anterior end of premaxilla, and inner membrane covering posterior part of dentary pigmented.

Proportions of 67 mm SL holotype are given first, followed (in parentheses) by those of the 127 mm SL specimen and then the 102–116 mm SL Taiwan specimens, as percentages of SL: predorsal length 29.4‒(26.5, 27.3, 29.6); preanal length 55.6‒(57.4, 55.4, 53.8); dorsal-fin base 59.6‒(59.2, 61.9, 64.0); anal-fin base 32.9‒(32.9, 31.6, 32.5); pelvic-fin length [tip broken off] –(23.8, 25.5, 26.5); caudal-fin length 38.7‒(31.0, 46.1, 56.5); body depth at anal-fin origin 29.2‒(26.5, 21.3, 24.0); head length 32.3‒(28.2, 26.1, 28.5); upper jaw length 17.0‒(16.0, 14.5, 14.9); upper jaw depth 7.9‒(7.0, 6.8, 6.9); orbit diameter 16.0‒(12.9, 11.2, 11.7). As percentages of head length: upper jaw length 52.8‒(56.6, 55.5, 52.2); orbit diameter 49.4‒(45.7, 42.7, 41.2). Life coloration unknown.

Comparisons. Owstonia hawaiiensis and O. ignota , the only other species with most of the diagnostic characters of O. grammodon , differ in lacking a premaxillary stripe (vs. prominent black stripe in O. grammodon ). These two species, together with Owstonia grammodon , also differ from most congeners with LL pattern 1 in having relatively small and numerous teeth (33‒39) in outer row of each premaxilla (see Table 3 ).

Etymology. A combination of the Greek gramme (line, or row) and odon (tooth), presumably in reference to the mostly single rows of teeth in the jaws.

Distribution. ( Fig. 23 ) Known from the type locality in Sulawesi, Indonesia based on three specimens, all in relatively poor condition, taken together in the same trawl haul in 375 m, and two fish market specimens from Taiwan.

Remarks. Fowler's (1934a) original description of this species was based on a single Albatross specimen but we found two others with identical collection data. The type locality given in the original description "between Gillolo and Kayoa Islands" is erroneous for Albatross station D.5629 but correct as recorded for the holotype USNM 93167 in material examined. See Smith and Williams (1999) for history of the Albatross Philippine Expedition and its fishes. Fowler's counts of anal-fin rays and gill rakers (I, 17 and 8 + 21 respectively) for the holotype are also inaccurate; our counts for the same elements are I, 13 and 11 + 24. The largest Sulawesi specimen has the highest gill raker counts.

The Sulawesi specimens differ from the two Taiwan specimens in having 11 + 17 (vs. 12 + 16) vertebrae and anal-fin pterygiophores anterior to 1st haemal spine 3 (vs. 4), but are otherwise very similar, especially in having relative high numbers of teeth in the outer row of each premaxilla (33–34 in Taiwan specimens vs. 36−39 in those from Sulawesi). When more specimens from both localities become available, the taxonomic status of fish from Taiwan should be re-evaluated.

Records of O. grammodon from Japan by various Japanese authors are probably all based on misidentifications of O. japonica (see synonymy for that species), because they did not list that species in their accounts and reported I, 14 anal-fin rays (versus our count of I, 13 for O. grammodon , see Table 4). In addition to having a different number of anal-fin soft rays, Owstonia japonica has fewer teeth in the outer row of each premaxilla (14−23, vs. 33−39), more total gill rakers (41−46, vs. 35−40, see Table 7 ), and lower limb margin of preopercle with spines (vs. preopercular spines absent in O. grammodon ).

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

FIGURE 38. Owstonia grammodon, USNM 149321, 127 mm SL, Sulawesi, Doworra Island. Photograph by Sandra J. Raredon.