Search

For over two decades, assessments of geographic variation in mtDNA and small numbers of nuclear loci have revealed morphologically similar, but genetically divergent, intraspecific lineages in lizards from around the world. Subsequent morphological analyses often find subtle corresponding diagnostic characters to support the distinctiveness of lineages, but occasionally do not. In recent years it has become increasingly possible to survey geographic variation by sequencing thousands of loci, enabling more rigorous assessment of species boundaries across morphologically similar lineages. Here we take this approach, adding new, geographically extensive SNP data to existing mtDNA and exon capture datasets for the Gehyra australis and G. koira species complexes of gecko from northern Australia. The combination of exon-based phylogenetics with dense spatial sampling of mitochondrial DNA sequencing, SNP-based tests for introgression at lineage boundaries and newly-collected morphological evidence supports the recognition of nine species, six of which are newly described here. Detection of discrete genetic clusters using new SNP data was especially convincing where candidate taxa were continuously sampled across their distributions up to and across geographic boundaries with analyses revealing no admixture. Some species defined herein appear to be truly cryptic, showing little, if any, diagnostic morphological variation. As these SNP-based approaches are progressively applied, and with all due conservatism, we can expect to see a substantial improvement in our ability to delineate and name cryptic species, especially in taxa for which previous approaches have struggled to resolve taxonomic boundaries.

The methods used to detect and describe morphologically cryptic species have advanced in recent years, owing to the integrative nature of molecular and morphological techniques required to elucidate them. Here we integrate recent phylogenomic work that sequenced many genes but few individuals, with new data from mtDNA and morphology from hundreds of gecko specimens of theGehyra variegatagroup from the Australian arid zone. To better understand morphological and geographical boundaries among cryptic forms, we generated new sequences from 656Gehyraindividuals, largely assigned toG. variegatagroup members over a wide area in Western Australia, with especially dense sampling in the Pilbara region, and combined them with 566Gehyrasequences from GenBank, resulting in a dataset of 1,222 specimens. Results indicated the existence of several cryptic species, from new species with diagnostic morphological characters, to cases when there were no useful characters to discriminate among genetically distinctive species. In addition, the cryptic species often showed counter-intuitive distributions, including broad sympatry among some forms and short range endemism in other cases. Two new species were on long branches in the phylogram and restricted to the northern Pilbara region: most records of the moderately sizedG. incognitasp. nov. are near the coast with isolated inland records, whereas the small-bodied saxicolineG. unguiculatasp. nov. is only known from a small area in the extreme north of the Pilbara. Three new species were on shorter branches in the phylogram and allied toG. montium. The moderately sizedG. cryptasp. nov. occurs in the western and southern Pilbara and extends south through the Murchison region; this species was distinctive genetically, but with wide overlap of characters with its sister species,G. montium. Accordingly, we provide a table of diagnostic nucleotides for this species as well as for all other species treated here. Two small-bodied species occur in isolated coastal regions:G. capensissp. nov. is restricted to the North West Cape andG. ocellatasp. nov. occurs on Barrow Island and other neighbouring islands. The latter species showed evidence of introgression with the mtDNA ofG. cryptasp. nov., possibly due to recent connectivity with the mainland owing to fluctuating sea levels. However,G. ocellatasp. nov. was more closely related toG. capensissp. nov. in the phylogenomic data and in morphology. Our study illustrates the benefits of combining phylogenomic data with extensive screens of mtDNA to identify large numbers of individuals to the correct cryptic species. This approach was able to provide sufficient samples with which to assess morphological variation. Furthermore, determination of geographic distributions of the new cryptic species should greatly assist with identification in the field, demonstrating the utility of sampling large numbers of specimens across wide areas.

Spontaneous anorexia has been documented in various animal species and is usually associated with activities competing with food intake. In natural conditions, most female aspic vipers (Vipera aspis) stop feeding during the two months of pregnancy. We carried out a simple experiment on 40 pregnant females to determine whether anorexia was obligatory or facultative, and to investigate the energetic consequence of fasting on post-partum body condition and litter traits. Three diet treatments were applied during gestation: no food, one feeding occasion, and two feeding occasions. Twelve nonpregnant, unfed females were used as a control group. Most gravid females accepted captive mice during gestation, suggesting that anorexia reported in the field was a side effect of the tremendous changes in activity pattern associated with pregnancy. Mass loss was high for unfed reproductive females, indicating high energy expenditure associated with embryo maintenance. Prey consumption allowed compensation for metabolic expenditure and enhanced post-partum female body condition, but had no effects on litter characteristics. The magnitude of the metabolic expenditure during gestation appeared to be independent of fecundity.

A major problem for biodiversity conservation and management is that a significant portion of species diversity remains undocumented (the ‘taxonomic impediment’). This problem is widely acknowledged to be dire among invertebrates and in developing countries; here, we demonstrate that it can be acute even in conspicuous animals (reptiles) and in developed nations (Australia). A survey of mtDNA, allozyme and chromosomal variation in the Australian gecko, genusDiplodactylus, increases overall species diversity estimates from 13 to 29. Four nominal species each actually represent multi-species complexes; three of these species complexes are not even monophyletic. The high proportion of cryptic species discovered emphasizes the importance of continuing detailed assessments of species diversity, even in apparently well-known taxa from industrialized countries.

Recent surveys in the Kimberley region of Western Australia have provided new material to reassess species diversity in the gecko genus Gehyra. Here we focus on morphological and molecular genetic variation within the G. occidentalis and G. xenopus groups. We fi rst describe a new small-bodied species that has a wedge of granules between the lamellae on the basal part of the toe pads, similar to that seen in G. xenopus. This new species has a dorsal pattern comprising transverse rows of dark and light spots or lines on a dull reddish-brown background and genetically is not closely related to G. xenopus. The second new species is supported as closely related to G. occidentalis, but differs by being smaller in body size and having more than 40 precloacal and femoral pores in adult males, darker background colouration and pattern with thick dark lines and pale spots or bars (v. large dark and pale spots). These fi ndings further add to the large number of endemic species known from the rugged, high rainfall zone of the north-west Kimberley.

Surveys to remote tropical areas of the world have continued to lead to new discoveries of species, including vertebrates. A recent survey in January 2010 to the northwest Kimberley was undertaken to look for new frog species. Among the taxa discovered (including plants and land snails) was a small species of Litoria in the Prince Regent River Nature Reserve. Litoria axillaris sp. nov. is superfi cially similar in appearance (body shape, limbs and webbing) and in call structure to L. tornieri, a ground hylid which occurs in the Kimberley region and east to the Top End of the Northern Territory. The new species differs, however, in being smaller (22.0-25.0 v. 28.5-33.0 mm total length), in possessing extensions of the lateral stripe posterior to the tympanum on the lower lateral surface and anteriorly to the tip of the snout, in having dorsolateral streaks, the upper lip pigmented, the chin only weakly pigmented on the edge of the jaw, and having thighs with poorly-defi ned markings. Litoria axillaris sp. nov. shares with L. tornieri similar advertisement calls, including intermittent and repetitive calls; however, pulse rates of calls of the new species are less than half of those in L. tornieri. Further, habitat use also differs noticably, with L. axillaris sp. nov. being found on top of sandstone platforms in highly dissected terrain while L. tornieri occurs in grasslands in tropical savannah. The new species is the fi fth to be discovered and described as a result of wet season surveys targeting frogs in the Kimberley region since 2005. Its discovery highlights the high vertebrate endemism of the high rainfall zone of the northwest Kimberley and underscores the importance of protecting this biodiversity through the establishment of more extensive reserves and their proper management.

Egernia depressa is an extremely spiny species of scincid lizard that occurs in several populations with highly variable morphology in western Australia. Using a combination of fi xed morphological character differences and mitochondrial DNA sequence data, we found evidence for four species level groups within the complex. We restrict E. depressa to the log-inhabiting population from south-western Australia and resdescribe the species, and describe three new species from the arid zone: two from the Pilbara and one from the central ranges. In addition to the genetic differences, the species differ in head size, limb length, tail shape, colouration and scalation. Many of the morphological characters appear to be adaptations to log or rock-dwelling, with the log-dwelling E. depressa having brown colouration, large head, limbs and tail and long thin spines on the body and tail. The two Pilbara species are not each other's closest relatives, yet they resemble each other the closest, probably owing to a suite of characters adapted for living in rock crevices such as yellow to reddish colouration, smaller head and limbs, narrower tail and short strong spines on the body and tail. The central ranges species appears to have a combination of characters from log and rock-dwelling forms and is the most isolated of the four species.