Aetobatus ocellatus (Kuhl)

Fernando, Daniel, Bown, Rosalind M. K., Tanna, Akshay, Gobiraj, Ramajeyam, Ralicki, Hannah, Jockusch, Elizabeth L., Ebert, David A., Jensen, Kirsten & Caira, Janine N., 2019, New insights into the identities of the elasmobranch fauna of Sri Lanka, Zootaxa 4585 (2), pp. 201-238 : 205

Aetobatus ocellatus (Kuhl)

( Figs. 2A , 6A, B )

The eight specimens of Aetobatus Blainville from Sri Lanka were collected from landing sites in Palkanththura (SL-2) and Pukulam (SL-7) in the North Western Province and from fish markets in Kottadi (SL-26, SL-27, SL- 62), Munai (SL-41), and Vankalai (SL-68, SL-69) in the Northern Province. All eight specimens exhibited the general color pattern that distinguishes Aetobatus ocellatus from its four described congeners in that the dorsal disc surface bears small white, round spots that do not extend onto the head. Some variation was seen across specimens —in the cases of SL-41, SL-62, and SL-69; the white spots were essentially restricted to the posterior margins of the disc and the pelvic fins. The tree resulting from Neighbor-Joining analysis of NADH2 data, which included representation of all four described species and the potentially undescribed species referred to as Aetobatus cf. ocellatus 1 and Aetobatus cf. ocellatus 2 by Naylor et al. (2012a), generally supports this identification in that all eight specimens clustered most closely with our reference specimen of A. ocellatus from Malaysian Borneo (BO- 296; JQ519092 ). However, within that cluster, two subclusters were apparent. Specimens SL-26 and SL-41 were identical in sequence, differing from the reference specimen of A. ocellatus by 6 bp. The six specimens in the second subcluster (SL-2, SL-7, SL-27, SL-62, SL-68, and SL-69), which differed from one another by 0–1 bp, differed from those in the first subcluster by 8–13 bp. However, these subclusters did not correspond to the color pattern differences seen. Investigation of additional specimens of Aetobatus from Sri Lanka is recommended and a comprehensive review of the white-spotted eagle rays in the Indo-West Pacific is sorely needed.

This species has been referred to as Aetobatus narinari (Euphrasen) in all prior reports from Sri Lanka (see De Silva 1978, 2006, 2015; De Bruin et al. 1995; Morn et al. 1998). However this name is now reserved for the Atlantic member of this genus (see White et al. 2010).

Figures

FIGURE 2. Neighbor-Joining trees of p-distances based on 1,044 bp of aligned NADH2 sequence data for individual batoid genera or groups of genera. Taxon names are followed by country, host specimen number (in parentheses), and GenBank number. Outgroup taxa used in each analysis were omitted from the individual trees. Scale bar values indicate substitutions per site. Specimens deposited in the Blue Resources Trust Ichthyology Collection are indicted by stars (see text for details). A. Aetobatus (Aetobatidae). B. Brevitrygon (Dasyatidae). C. Himantura (Dasyatidae). D. Maculabatis (Dasyatidae). E. Neotrygon (Dasyatidae). F. Pastinachus (Dasyatidae). G. Pateobatis (Dasyatidae). H. Urogymnus (Dasyatidae).

FIGURE 6. Aetobatus ocellatus (Aetobatidae) (A–B) and Brevitrygon sp. 1 (Dasyatidae) (C–D). A. Dorsal surface of immature male (SL-26). B. Dorsal surface of mature female (SL-41). C. Dorsal surface of maturing male. D. Thorns and denticles on base of tail of mature male (dorsal surface; SL-36).