Apogon arenatus Bleeker, 1860

Russell, Barry C., Fraser, Thomas H. & Larson, Helen K., 2010, Castelnau’S Collection Of Singapore Fishes Described By Pieter Bleeker, Raffles Bulletin of Zoology 58 (1), pp. 93-102 : 99

Apogon arenatus Bleeker, 1860

Apogon arenatus Bleeker, 1860c , No. 171 ( Fig. 13 ), has few markings other than small reddish or pinkish spots and some yellowish area, on the snout. The angled mouth and body shape suggests a fairly compressed fish. A species from among Zoramia , Archamia , Siphamia , and Apogon could be considered based on the absence of any stripes, bars or dark marks. The notes refer to “ Apogon sp nov, macropteroides CV même qui 483, Apogon arenatus Castelnau ”. Castelnau drew at least two, perhaps three species now in Archamia : Apogon macropteroides, No. 482 ( Fig. 14 ); Apogon macropteroides, No. 483 ( Fig. 15 ); and Apogon bleekeri, No. 625 ( Fig. 16 ). These species are painted with long anal fin bases in contrast to the painting of Apogon arenatus . Bleeker did not alter the original description in his later publications. Bleeker’s abbreviated comments on this species provide little help in determining the identity of this fish. A few species were considered: Apogon gularis , Zoramia leptacantha , Archamia fucata and Siphamia jebbi . None of these species have been recorded from Singapore, but all have distributions that suggest they are likely to occur there. Apogon gularis and Siphamia jebbi are found in deeper waters, and therefore, less likely to be collected or seen by Bleeker. Siphamia jebbi has a bioluminous organ system located along the side of the abdomen extending on to the peduncle ( Allen, 1993). Presumably, this structure would have been noticed by Castelnau and subsequently included in his painting. Apogon gularis has a dark mark on the snout (Fraser & Lachner, 1984) which is not present in the painting. Zoramia leptacantha (Bleeker, 1856–57) is the only species of Zoramia without clusters of melanophores and/or a dark spot on the caudal peduncle or basicaudal region. This species can have a very long filamentous spinous dorsal spine, and has a few yellowish bars on the opercle and adjacent body, a line present along the base of the dorsal fins onto the peduncle and a line along the base of the anal fin onto the peduncle (Fraser & Lachner, 1985; Kuiter & Kozawa, 2001). These distinctive characteristics are all absent in the painting. Archamia fucata has a very long anal fin, finely curved bars on the body and a yellowish snout. Most photographs of Archamia fucata show a darkish basicaudal spot except one photograph of a specimen from Bali with a very faint and diffused caudal marking (Kuiter & Kozawa, 2001). The anal fin and dorsal fin base are not significantly different in their lengths in the painting which would eliminate any Archamia , but not Zoramia .

We believe that the painting of Apogon arenatus is most likely from a specimen of Zoramia , probably Z. leptacantha (Bleeker,1856–57) without the fi lamentous dorsal spine. Unless another undescribed species of Zoramia is recognized and corresponds with arenatus , Bleeker’s name should be treated as a junior synonym of Zoramia leptacantha .

Figures

Figs. 10–17. Figures 10, 11: dried mounted specimens in the collection of the Zoological Museum of the University of Liège, Beligium (ZMUL), catalogue numbers 2378a and 2378b. Figures 12–17: Castlenau’s paintings, numbers 163, 171, 482, 483, 625 and 193, respectively.