Spatial genetic structure in the vulnerable smooth-coated otter (Lutrogale perspicillata, Mustelidae): towards an adaptive conservation management of the species

Since Fraser and Bernatchez’s seminal paper, the concept of adaptive conservation has inspired in situ and ex situ management aimed at preserving the genetic distinctiveness of natural populations and their associated evolutionary potential. This goal is particularly worthwhile in an epoch of rampant biotic homogenisation (i.e., the progressive replacement of native biotas with locally expanding non-natives) driven by global change in the context of the ongoing Anthropocene extinction. Under these premises, we provided here a molecular biogeographic framework based on macro-regional scale sampling to support conservation initiatives for the smooth-coated otter (Lutrogale perspicillata). This species, ranging from Pakistan across the Indian subcontinent and Indochina to Sundaland and occurring also in Iraq and extreme southwestern Iran with an isolated population, has experienced a rapid decline over the last decades and is now listed as ‘Vulnerable’ by the IUCN. We sequenced a 307 bp-long fragment of the mitochondrial Cytochrome-b (Cyt-b) gene in modern and museum samples (n = 77, of which 23 are new with respect to a previous study) from the entirety of the species range, including holotypes of the three traditionally recognised morphological subspecies (L. p. maxwelli, L. p. sindica, and L. p. perspicillata). We corroborated the occurrence of three patently diverging genetic groups (Middle East, South, and South East Asia) and defined their spatial boundaries. Incidentally, we found that the holotype of L. p. perspicillata from Indonesia (dated 1821) held oriental small-clawed otter (Aonyx cinereus) maternal DNA. Although a few evident morphological similarities shared by this specimen with the oriental small-clawed otter cast serious doubts on its current taxonomical identification, it is suggested that the recently disclosed hybridisation in the wild between L. perspicillata and A. cinereus in Singapore might be more geographically extensive and/or have occurred earlier than believed. In conclusion, the molecular biogeographic picture herein is intended to form the basis for supporting management in ex situ facilities (e.g., exchange of individuals among zoos) and for implementing the genetic tracking of illegally traded otters in the attainment of adaptive conservation for L. perspicillata.