Owstonia ignota

description

Description. A species of Owstonia with LL pattern type 1, consisting 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 ray 19. Dorsal fin III, 20; anal fin I, 13; pectoral fin 20; gill rakers 14 + 27 = 43. Vertebrae: precaudal 11, caudal 17, total 28; anal-fin pterygiophores anterior to 1 st haemal spine 3. Oblique body scale rows in mid-lateral series about 37 or 38; nape scaly and cheek scale rows about 3 or 4. Lower limb margin of preopercle without spines. Papillae in slight depression behind tip of premaxillary ascending processes 4, relatively large and arranged in 2 almost equally spaced pairs. Teeth in outer row of each premaxilla 38 / 39, anterior ones larger and more strongly hooked; 2 ‒ 3 inner teeth anteriorly. Teeth in lateral row of each dentary 15 / 16, with 6 or 7 of the anterior ones robust and strongly hooked (Fig. 10 E); symphyseal teeth 3 ‒ 4, relatively large, conical, and with 2 similar-sized inner teeth anteriorly. Pelvic fin presumably sexually dimorphic, depressed pelvic fin extending beyond last anal-fin

Hidden diversity in deep-water bandfishes: review of Owstonia with descriptions of twenty-one new species (Teleostei: Cepolidae: Owstoniinae)

description

Owstonia n. sp. Myers & Donaldson, 2003: 631 (listed, Saipan).

Hidden diversity in deep-water bandfishes: review of Owstonia with descriptions of twenty-one new species (Teleostei: Cepolidae: Owstoniinae)

diagnosis

Diagnosis. A species of Owstonia with LL pattern type 1; lower limb margin of preopercle without spines; dorsal fin III, 19; no dark premaxillary stripe; adults with about 38 – 39 teeth in outer row premaxilla; papillae in slight depression behind tip of ascending process of premaxillae without a cluster of about 5 minute papillae present between the posterior pair of relatively large papillae.

Hidden diversity in deep-water bandfishes: review of Owstonia with descriptions of twenty-one new species (Teleostei: Cepolidae: Owstoniinae)

discussion

Remarks. Our decision to recognize Owstonia ignota and O. hawaiiensis as different species has the advantage of calling attention to both of them (despite their minor but presumably consistent distinguishing characters). With opposite sexes only and single specimens available for each of these species, we cannot dismiss the possibility that dentition differences (Figs. 10 D, 10 E) are due to sexual dimorphism. However, we have also been influenced by the fact that about 25 % of the shore fishes of the Hawaiian Islands, including species to 200 m, are apparently endemic (Randall, 2007). The Marianas Islands are located along the western margin of the Pacific Plate near the eastern edge of the Philippine Plate. Although the geological history of the region is very complex (Springer, 1982), it is doubtful that a benthic deep water species whose ecology appears to be closely associated with sea-floor spreading would have a distribution that extends from near the western margin of the Pacific Plate to the Hawaiian Islands. Further discussion of the possible zoogeographic affinities of Owstonia ignota is unjustified in view of the limited sampling of seamounts in the central Pacific regi

Hidden diversity in deep-water bandfishes: review of Owstonia with descriptions of twenty-one new species (Teleostei: Cepolidae: Owstoniinae)