Brevitrygon imbricata, Bloch & Schneider

Golzarianpour, Kiavash, Malek, Masoumeh, Golestaninasab, Mehdi, Sarafrazi, Alimorad, Kochmann, Judith & Klimpel, Sven, 2020, Insights into the Urogymnid whiprays (Chondrichthyes: Batoidea) in the Persian Gulf and the Gulf of Oman, with an amendment of their diagnostic characteristics and dispersal range, Zootaxa 4819 (2), pp. 316-334 : 330

Brevitrygon imbricata or Brevitrygon walga?

Previous molecular studies suggested that B. walga is the only representative of the genus Brevitrygon in the Persian Gulf and the Gulf of Oman ( Naylor et al. 2012).Also, the recent revision by Last et al. (2016a) remarked that among four species of the genus Brevitrygon , both B. walga and B. imbricata are restricted to the Indian Ocean while the first is common in the northwestern part of the region (The Persian Gulf and the Gulf of Oman) and the last one inhabits western waters of India ( Last et al. 2016b). It seems that some previous reports ( Henderson and Reeve 2011; Almoji et al. 2015) and sequences deposited in the databases ( Henderson et al. 2016; Naylor et al. 2012) might belong to misidentified specimens (Gavin Naylor pers. comm.).

Therefore, all materials in our collection were morphologically re-examined. The results revealed that specimens collected from the Persian Gulf and the Gulf of Oman have up to 12 enlarged thorns on the base of the tail, 2 (n=60) to 3 (n=29) stinging spines, and the denticle band does not cover the trunk area, which is consistent with all diagnostic characteristics of B. walga . So, the current morphological and molecular (e.g. branch support and genetic distance) evidence support the idea that there is a monophyletic clade and B. walga is the only representative of the genus in the region. Recently, Fernando et al. (2019) reported an unknown taxon that clustered closely to well outside the species. This finding shows that there may be more cryptic species in the genus and more detailed examination should be conducted.