Cleft Palate Syndrome in the Endangered Spectacled Flying Fox (Pteropus conspicillatus): Implications for Conservation and Comparative Research

SIMPLE SUMMARY: The spectacled flying fox (Pteropus conspicillatus) is an endangered frugivorous megabat with a restricted habitat in the Wet Tropics World Heritage Area in far north Queensland, Australia. Its population is in decline, and as such, mortality events in the species require investigation and the development of mitigation strategies. Cleft palate syndrome, first observed in the spectacled flying fox population in 1998, has produced sporadic neonatal mortality events over the past two decades. This study presents the rudimentary morphological signs of cleft palate syndrome in spectacled flying fox neonates, presenting gross pathology of syndromic signs upon visual inspection and a histological examination of palate malformations. It examines syndrome incidence data from the past two decades and reviews recent flying fox research to develop hypotheses related to the causes of the syndrome and to develop future research focuses. This, and future studies, will provide a greater understanding of the risk factors associated with the syndrome to guide the development of mitigation strategies that can deliver conservation outcomes for an endangered species, while presenting a unique opportunity for a novel comparative study into syndromic cleft palate in mammalian species. ABSTRACT: Cleft palate syndrome, first observed in the spectacled flying fox population in 1998, has produced sporadic neonatal mortality events over the past two decades, with an estimated incidence of up to 1/1000 births per year. This study presents a rudimentary characterisation of the syndrome, presenting gross pathology of syndromic signs upon visual inspection, a histological examination of palate malformations, and syndrome incidence data representing the past two decades. The syndrome presents with a range of signs, primarily congenital palate malformations ranging from a pinhole cleft to a complete hard and soft palate deficit, resulting in the death or abandonment of neonates shortly after birth. The congenital palate malformations are often associated with claw deformities, wiry facial hair, and in some instances, muscle weakness and neurological signs. The natural occurrence of the lethal congenital orofacial birth defects in the spectacled flying fox presents a unique opportunity for the investigation of putative aetiologies, drawing parallels between bat and other mammalian cleft palate risk factors. Further syndrome investigation has the potential to deliver both biodiversity conservation and comparative veterinary and biomedical outcomes.