Two cases of probable hybridisation between the pufferfishes |Arothron meleagris (Anonymous 1798) and A. nigropunctatus (Bloch and Schneider 1801) on a fringing reef at Réunion Island

Abstract

Two individuals displaying mixed features of the colour patterns distinctive of Arothron meleagris and A. nigropunctatus were observed on the fringing reef at Réunion Island, between September 2012 and August 2013. Because many hybrid fish have been first identified through colour patterns that are intermediate between two known species, these pufferfish individuals were suspected to be hybrids. However, since no specimen was collected for examination, a hypothesis that the observed individuals could be hybrids is based on comparison of their colouration with colour patterns documented for A. meleagris and A. nigropunctatus. Several factors favouring hybridisation are met on this reef, particularly a difference in abundance between the two putative parental species. Since larval retention and self-recruitment are considered probable at Réunion, these individuals could be the progeny of interbreeding populations of these species on this reef. To our knowledge, only one hybrid has ever been reported in the genus Arothron, although without genetic confirmation. This implies that the existence of potentially interfertile species in this genus remains a hypothesis. Our field observations provide additional data supporting this hypothesis.

Keywords: abundance, colouration, descriptive taxonomy, hybrids, interfertile species, self-recruitment, Tetraodontidae, western Indian Ocean