Albula glossodonta ( Forsskål, 1775 )

Matsunuma, Mizuki, Nagaya, Nene, Hidaka, Koichi & Kai, Yoshiaki, 2022, Taxonomic Reassessment of Albula (Albuliformes: Albulidae) from Japan and Adjacent Waters with Reliable Records of Albula argentea, A. koreana and A. oligolepis from Japan, Species Diversity 27 (2), pp. 259-277 : 267-269

Albula glossodonta ( Forsskål, 1775)

[Standard Japanese name: Marukuchi-sotoiwashi] ( Figs 1D , 3B , 4D ; Table 6)

Albula glossodonta: Hidaka et al. 2004: 62 , figs 1A, 2A (description; Iriomote-jima Island , Okinawa, Japan; specimen: IORD 76-1074 ); Takagi et al. 2010: 177, unnumbered fig. (atlas; Ainan, Ehime, Japan; specimen not retained) .

Material examined. JAPAN: NSMT-P 102552 (formerly IORD 76-1074 ), 273.5 mm SL, Iriomote-jima Island, Ryukyu Islands , Okinawa Prefecture, Japan, H . Kishimoto, gill net, 14 October 1976.

Diagnosis. A species of Albula distinguished from Indo-Pacific congeners by having a rounded lower jaw tip.

Description. Meristics and morphometrics taken from examined specimen are given in Table 6. Characters applicable to both A. glossodonta and A. argentea are not repeated here, except for the following significant features: anterior portion of parasphenoid tooth patch rounded without an anterior extension, its anterior tip not exceeding level of anterior tips of mesopterygoid tooth patches. Lower jaw tip relatively rounded ( Fig. 4D ). Single row of 8 embedded scales along ventral edge of preopercle, just posterior to maxilla. Posterior tip of depressed pelvic fin not reaching anus. 8 horizontal scale rows between mid-dorsal-fin base and lateral line; 9th scale row short, restricted to around dorsal fin origin.

Color of fresh specimen: Cheek without a yellow stripe ( Fig. 1D ). Iris reddish yellow, without a stripe crossing black pupil. Dorsal fin rays gray, blackish dorsally; membranes semitranslucent, with dense melanophores. Anal fin white, with dense melanophores. Pectoral fin outer surface whitish, inner axis coloration not apparent on specimen photograph. Pelvic fin whitish entirely (basal portion not yellowish), anterior portion with dense melanophores. Caudal fin gray with narrow black margin.

Color of preserved specimen: Head, body and fins becoming entirely yellowish-brown ( Fig. 3B ); black arched band on snout tip retained, no blotch under band; no dark marking around nostril; longitudinal lines on body retained as pale brown lines.

Distribution. Albula glossodonta is widely distributed in the Indo-Pacific region, including the Red Sea (see Pickett et al. 2020). In Japan, only two examples of large adults from the southern Ryukyu Islands and Ehime Prefecture (Shikoku Island) have been recorded ( Hidaka et al. 2004; Takagi et al. 2010; Fig. 7 ). Lee et al. (2021) reported a leptocephalus specimen of the species from southern Korea (north of Jeju Island). Leptocephalus larvae of the species may be regularly transported by the Kuroshio Current from southern regions, but the settlement of such appears to be unsuccessful, since juvenile and subadult specimens have at no time been reported from Japanese waters. The adult Japanese examples suggest occasional migration of large adults along the Kuroshio Current.

Remarks. Hidaka et al. (2004) first reported the species from Japan on the basis of a single specimen (NSMTP 102552, formerly IORD 76-1074) from Iriomote-jima Island, southern Ryukyu Islands. That specimen was also examined here. Hidaka et al. (2004) also proposed the standard Japanese name “Marukuchi-sotoiwashi” for the species.

Figures

Fig. 1. Fresh specimens of (A) Albula argentea, (B) A. koreana, (C) A. oligolepis and (D) A. glossodonta from Japan. (A) KAUM–I. 80897, 293.5mm SL, Uchinoura Bay, Kagoshima; (B) KAUM–I. 1246, 250.1mm SL, Kasasa, Minamisatsuma, Kagoshima; (C) NSMT-P 129038, 289.0mm SL, Amami-oshima Island, Kagoshima; (D) NSMT-P 102552, 273.5mm SL, Iriomote-jima Island, Okinawa. Photos by KAUM (A, B), NSMT (C) and H. Kishimoto (D).

Fig. 3. Preserved specimens of (A) Albula argentea, (B) A. glossodonta, (C) A. koreana and (D) A. oligolepis from Japan. (A) KAUM–I. 80897, 293.5mm SL, Uchinoura Bay, Kagoshima; (B) NSMT-P 102552, 273.5mm SL, Iriomote-jima Island, Okinawa; (C) KAUM–I. 1246, 250.1mm SL, Kasasa, Minamisatsuma, Kagoshima; (D) NSMT-P 129038, 289.0mm SL, Amami-oshima Island, Kagoshima.

Fig. 4. Ventral views of lower jaw of preserved specimens of (A) Albula argentea, (B) A. koreana, (C) A. oligolepis and (D) A. glossodonta. (A) KAUM–I. 80897, 293.5mm SL, Kagoshima, Japan; (B) KAUM–I. 1246, 250.1mm SL, Kagoshima, Japan; (C) NSMT-P 129038, 289.0mm SL, Kagoshima, Japan; (D) NSMT-P 102552, 273.5mm SL, Okinawa, Japan. Bars indicate 2mm.

Fig. 7. Distributional map of Albula argentea (red circles), A. glossodonta (blue diamond), A. koreana (green downward-triangles) and A. oligolepis (yellow upward-triangles) in Indo-Pacific region (A) and Japan and adjacent waters (B). Albula glossodonta omitted in A. Closed and open symbols indicate records based on examined specimens and literature.