Pempheris oualensis Cuvier, 1831

Koeda, Keita & Bessho-Uehara, Manabu, 2024, A review of the genus Pempheris (Teleostei, Pempheridae) found in Japan and Taiwan, ZooKeys 1220, pp. 123-163 : 123-163

Pempheris oualensis Cuvier, 1831

Figs 9 , 10 , Suppl. material 2 Standard Japanese name: Yume-hatampo

Pempheris oualensis Cuvier in Cuvier & Valenciennes, 1831: 299 (type locality: Kosrae, Caroline Islands); Masuda et al 1975 (in part): 199; Hayashi 1984 (in part): 161; Chen et al. 1995 (probably in part): 25; Shao et al. 2008: 254; Koeda et al. 2010 a: 72, fig. 1; Koeda et al. 2010 b: 81; Koeda et al. 2012 a: 71; Koeda et al. 2013 a: 231, fig. 1 b; Koeda et al. 2013 b: 126; Koeda et al. 2014: 327; Koeda and Motomura 2015: 139; Koeda et al. 2015: 276, fig. 1; Koeda et al. 2016 b: 50, fig. 225; Koeda and Motomura 2017 a; Koeda 2017 a: 7, fig. 2 (upper fig.); Kimura et al. 2017: 119, fig. 7; Planning and Tourism Division of Kikai Town 2017: 4, unnumbered figs; Nakae et al. 2018: 266; Koeda 2018 a: 194, unnumbered figs; Koeda 2018 b: 298, unnumbered fig.; Mochida and Motomura 2018: 30; Koeda 2019: 928, unnumbered figs; Motomura and Uehara 2020: 45; Koeda 2020 b: 928, unnumbered figs; Motomura 2023: 129.

Pempheris otaitensis (not Cuvier, 1831): Schmidt 1913: 121; Randall et al. 1997 (in part): 35, pl. 8 (fig. F).

Pempheris sp. : Hatooka 2002 (in part), 878; Motomura et al. 2010 (in part): 131, fig. 253; Hatooka and Yagishita 2013 (in part): 984.

Diagnosis.

Counts of holotype and non-types are given in Table 2 of Koeda et al. (2010 a). Dorsal-fin rays VI, 9–10; anal-fin rays III, 38–46; pectoral-fin rays 17–19; pored lateral-line scales 60–72; scale rows above lateral line 5 1 / 2–7 1 / 2, usually 6 1 / 2; scale rows below lateral line 13–17; predorsal scales 33–44; circumpeduncular scales 18–22; gill rakers 8–9 + 20 – 22 = 28–31; head length 27.7–31.5 %; body depth 40.9–48.2 %; eye diameter 36.4–43.9 %; upper jaw length 50.0–56.0 %; maximum 208 mm SL, usually <180 mm SL; scales weakly ctenoid, deciduous, thin, semicircular in shape, far wider than long ( Koeda et al. 2013 a: fig. 2 a); body silver; distinct blackish blotch on pectoral-fin base; anterior margin of dorsal fin zonally blackish; blackish band on anal-fin base with rarely blackish band on its margin; upper margin of pectoral fin dusky; villiform tooth band extending outside lips on large specimen; abdomen cross-sectional outline V-shaped.

Distribution.

Widely distributed in the western to central Pacific Ocean (not in the Hawaiian Islands), and Christmas Island and Cocos-Keeling Island in the Indian Ocean. In Japanese waters, this species is known from Tanega-shima to Yonaguni-jima islands in the Ryukyu Archipelago, Minamidaito-jima Island in the Daito Islands, and Haha-shima and Chichi-jima islands in the Ogasawara Islands. In Taiwanese waters, this species is known from Nang-fang-ao in Yilan County, Yeh Liu in New Taipei City, Tainan County, Chung-chou in Kaohsung County, Hengchung, and Kenting in Pingtung County, Fugang in Taitung County, and Lanyu (Fig. 10 ).

Remarks.

This species has similar characters as Pempheris otaitensis Cuvier, 1831 and Pempheris ufuagari which share a distinct black blotch on pectoral-fin base and whose large body sizes reaches> 160 mm SL. However, P. oualensis is unique in having a dark coloration on the upper margin of its pectoral fin and a villiform tooth band extends outside the lips on large specimens. The scale count of this species varies among populations that specimens collected from the northwestern Pacific have 61–66 pored lateral-line scales, but specimens collected from southern Pacific have 67–71. Additionally, specimens collected from Andaman Sea have 5 ½ scale rows above lateral line, whereas those from the Pacific Ocean have 6 ½ or 7 ½, with the frequency of specimens with 7 ½ scale rows above lateral line being lower in the northwestern Pacific than in southern areas. In particular, the Andaman population may be a species distinct from the Pacific populations, but more specimens and genetic evidence are necessary to discuss whether the differences are interspecific or intraspecific.

Although Okada (1938) gave the Japanese name “ Ryukyu-hatampo ” to P. oualensis which was listed in Snyder (1912), specimen ( USNM 75468) used for the list was re-identified to P. adusta ( Koeda et al. 2013 b) . Therefore, the standard Japanese name “ Ryukyu-hatampo ” was adopted for P. adusta and the standard Japanese name “ Yume-hatampo ” was provided to P. oualensis by Koeda et al. (2010 a) who first reported this species from Japanese waters. This species is the largest species of Pempheris that reaches> 200 mm SL; the largest specimen was collected from the Ogasawara Islands and measured 208.8 mm SL ( KAUM – I. 74584).

Figures

Figure 9. Pempheris oualensis A fresh specimen (NMMB-P 27821, 175.4 mm SL, Hengchung, Pingtung, Taiwan) and B underwater photograph (Dobuiso, Ogasawara Islands, Japan).

Figure 10. Distribution of Pempheris oualensis based on the collection locality of the specimens.