MUSEUM DNA SUGGESTS A RECENT ORIGIN FOR OTTER HYBRIDIZATION IN SINGAPORE

The smooth-coated otter (Lutrogale perspicillata) and the Asian small-clawed otter (Aonyx cinereus) are two species distributed across southeastern Asia. Although their ranges largely overlap, introgressive hybridization and A. cinereus mitochondrial DNA capture have so far been documented only in Singapore, where no L. perspicillata maternal lineages seemingly persist. However, no information on the timing of this phenomenon is currently available. To address this gap, we genotyped the only museum specimen (dated 1938) of smooth-coated otter collected on the island, identifying the first individual whose maternal DNA is consistent with its phenotypically assessed species identity. Furthermore, according to its genetic affinity with conspecifics from the entire species’ range, we found that this specimen could be a disperser from Peninsular Malaysia. While this result lends support to the hypothesis that L. perspicillata × A. cinereus introgressive hybridization is a recent phenomenon, it relies on a single specimen and should therefore be interpreted with caution. More specifically, a genome-wide approach encompassing multiple present-day and archival specimens from across southeastern Asia is required to elucidate not only the timing but also the drivers of this phenomenon, which, as far as Singapore is concerned, may result from the combined effects of urban encroachment in nearby Peninsular Malaysia and greening policies in the city island. Understanding this phenomenon has important implications for conservation planning of both otter species, which are currently listed as Critically Endangered in the Singapore Red Data Book