Urogymnus granulatus (Macleay)

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 : 215-217

Urogymnus granulatus (Macleay)

( Figs. 2H , 10 D–H)

The left portion of the disc of a specimen (SL-13) found in a fish market in Puttalam in the North Western Province was preliminarily identifiable as Urogymnus granulatus based on the coloration of the dorsal surface of the disc which was yellowish brown with small white spots; it also had several irregular rows of enlarged, thorn-like denticles more or less restricted to the midline of the body. While this denticle pattern is inconsistent with that described for this species by Last et al. (2016a, b), it is consistent with that reported in the redescription of U. granulatus by Ishihara et al. (1993). This identification was supported by our molecular analysis in which this specimen was found to differ from our reference specimen of U. granulatus (CM03-74; JQ518808 ) from Australia by only a single bp. Our molecular work also confirmed the identity of a specimen, which has been deposited in the BRT Ichthyology Collection (SL-116; BRT-I 0030), collected from the Valaichchenai Fisheries Harbor in the Eastern Province earlier in the year, as U. granulatus . This immature specimen was identical to the reference specimen from Australia and differed from SL-13 by 1 bp.

This is the first report of U. granulatus from Sri Lanka. This may be the species referred to previously in Sri Lanka as Urogymnus africanus (Bloch & Schneider) by De Silva (1978) or possibly as Urogymnus asperrimus (Bloch & Schneider) (see De Bruin et al. 1995; Morón et al. 1998; De Silva 2006). Last et al. (2016b) suggested that both U. granulatus and U. asperrimus co-occur in Sri Lanka, and a specimen consistent with U. asperrimus collected since our survey confirms this. However, whether the form of this species in Sri Lanka is Urogymnus asperrimus 1 or Urogymnus asperrimus 2 (sensu Naylor et al. 2012a) remains to be determined.

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 10. Pateobatis jenkinsii (A–C) and Urogymnus granulatus (D–H) (Dasyatidae). A. Dorsal surface of mature female (SL-98). B. Wedge-shaped thorns and denticles on base of tail of mature female (SL-43). C. Dorsal surface of immature male (SL-101; BRT-I 0028). D. Dorsal surface of portion of disc of large specimen (partial; SL-13). E. Thorns and denticles on base of tail of mature specimen (SL-13). F. Ventral surface of portion of disc of large specimen (partial; SL-13). G. Dorsal surface of immature female (SL-116; BRT-I 0030). H. Scapular denticles of immature female (SL-116; BRT-I 0030).