Shedding new light on old species identifications: morphological and genetic evidence suggest a need for conservation status review of the critically endangered bat, Saccolaimus saccolaimus

Abstract

Information based on the accurate identification of species is a vital component for achieving successful outcomes of biodiversity conservation and management. It is difficult to manage species that are poorly known or that are misidentified with other similar species. This is particularly problematic for rare and threatened species. Species that are listed under endangered species classification schemes need to be identified accurately and categorised correctly so that conservation efforts are appropriately allocated. In Australia, the emballonurid Saccolaimus saccolaimus is currently listed as 'Critically Endangered'. On the basis of new observations and existing museum specimens, we used a combination of genetic (mitochondrial DNA sequence) and morphological (pelage characteristics, dig III : phalanx I length ratio, interupper canine distance) analyses to identify six new geographic records for S. saccolaimus, comprising~100 individuals. Our analyses also suggested that there are likely to be more records in museum collections misidentified as S. flaviventris specimens. The external morphological similarities to S. flaviventris were addressed and genetic, morphological and echolocation analyses were used in an attempt to provide diagnostic characters that can be used to readily identify the two species in the field. We recommend genetic testing of all museum specimens of Australian Saccolaimus to clarify species' distributions and provide data for reassessing the conservation status for both S. saccolaimus and S. flaviventris. Museum curators, taxonomists and wildlife managers need to be aware of potential species misidentifications, both in the field and laboratory. Misidentifications that result in misclassification of both threatened and non-threatened species can have significant implications.

DNA Barcoding and Microsatellites Help Species Delimitation and Hybrid Identification in Endangered Galaxiid Fishes

“…Accurate classification is thus an essential first step towards effective conservation of local biodiversity [2]–[3]. This is particularly critical in the Southern Hemisphere, where a high proportion of endemic species are poorly known, and are now threatened by non-native introductions [4].…”

Echolocation and distribution of Saccolaimus saccolaimus in north-western Australia

“…Radius, D S. flaviventris formed two discrete clusters in terms of spectral parameters. Subsequent study revealed that one of these clusters resembled S. saccolaimus sequences from the Northern Territory, illustrated in Milne et al (2009). Fortuitously, the echolocation sequence emitted by one of the vouchered S. saccolaimus specimens was being recorded when it was shot (flying through the beam of a spotlight), thus providing a reference sequence from the Kimberley.…”

“…Consequently, we have reassigned Kimberley sequences to S. saccolaimus if they match, or are in continuous sequence with pulse-series that match, (1) the Kimberley reference sequence (by specimen M49194, flying in open air above tree canopy) and/ or (2) the descriptors for sequence-types (b) and (c) in Fig. 4 of Milne et al (2009). Their study identified three different search mode sequences from Anabat-ZCAIM reference recordings of Northern Territory S. saccolaimus, each emitted in a different environmental setting.…”

“…Within each sequence-type, the individual pulses were of similar shape. Three distinct shapes can be discerned, and are among those illustrated in In terms of 'minimum frequency and characteristic call frequency', Milne et al (2009) concluded that all three types were different from pulse sequences by its syntopic acoustic neighbour, S. flaviventris, but having lumped the three types together for the statistical comparison, found '...the call signature could not be reliably used to distinguish' these two species (p. 506).…”

“…Two recent events prompted a reevaluation of these identifications. Firstly, a mitochondrial DNA study of specimens from Queensland and Northern Territory revealed that, although S. saccolaimus forms a single genetic clade in Australia, a proportion of the Northern Territory S. saccolaimus population lacks the bare rump and/or dorsal markings (Milne et al 2009). It also showed that adults have a narrower 'outer-upper canine width' (OC 1 W < 5.7 mm) than S. flaviventris.…”