Melanesia holds the world's most diverse and intact insular amphibian fauna

A new species of Lepidodactylus (Gekkonidae) from Misima Island, Papua New Guinea

We describe a new species of gecko in the Lepidodactylus novaeguineae group from Misima Island, Milne Bay Province, Papua New Guinea. Lepidodactylus exoris sp. nov. can be distinguished from congeners by aspects of body size, toe shape, scalation and colouration. This discovery provides the first confirmed instance of L. novaeguineae group and L. orientalis group species on the same island, and further emphasises high herpetofaunal endemism in the recently delimited Milne Bay Province Biodiversity Hotspot of far eastern Papua New Guinea.

The Amphibian Genomics Consortium: advancing genomic and genetic resources for amphibian research and conservation

Amphibians represent a diverse group of tetrapods, marked by deep divergence times between their three systematic orders and families. Studying amphibian biology through the genomics lens increases our understanding of the features of this animal class and that of other terrestrial vertebrates. The need for amphibian genomic resources is more urgent than ever due to the increasing threats to this group. Amphibians are one of the most imperiled taxonomic groups, with approximately 41% of species threatened with extinction due to habitat loss, changes in land use patterns, disease, climate change, and their synergistic effects. Amphibian genomic resources have provided a better understanding of ontogenetic diversity, tissue regeneration, diverse life history and reproductive modes, anti-predator strategies, and resilience and adaptive responses. They also serve as essential models for studying broad genomic traits, such as evolutionary genome expansions and contractions, as they exhibit the widest range of genome sizes among all animal taxa and possess multiple mechanisms of genetic sex determination. Despite these features, genome sequencing of amphibians has significantly lagged behind that of other vertebrates, primarily due to the challenges of assembling their large, repeat-rich genomes and the relative lack of societal support. The emergence of long-read sequencing technologies, combined with advanced molecular and computational techniques that improve scaffolding and reduce computational workloads, is now making it possible to address some of these challenges. To promote and accelerate the production and use of amphibian genomics research through international coordination and collaboration, we launched the Amphibian Genomics Consortium (AGC, https://mvs.unimelb.edu.au/amphibian-genomics-consortium ) in early 2023. This burgeoning community already has more than 282 members from 41 countries. The AGC aims to leverage the diverse capabilities of its members to advance genomic resources for amphibians and bridge the implementation gap between biologists, bioinformaticians, and conservation practitioners. Here we evaluate the state of the field of amphibian genomics, highlight previous studies, present challenges to overcome, and call on the research and conservation communities to unite as part of the AGC to enable amphibian genomics research to "leap" to the next level.

The Amphibian Genomics Consortium: advancing genomic and genetic resources for amphibian research and conservation

Amphibians represent a diverse group of tetrapods, marked by deep divergence times between their three systematic orders and families. Studying amphibian biology through the genomics lens increases our understanding of the features of this animal class and that of other terrestrial vertebrates. The need for amphibian genomic resources is more urgent than ever due to the increasing threats to this group. Amphibians are one of the most imperiled taxonomic groups, with approximately 41% of species threatened with extinction due to habitat loss, changes in land use patterns, disease, climate change, and their synergistic effects. Amphibian genomic resources have provided a better understanding of ontogenetic diversity, tissue regeneration, diverse life history and reproductive modes, antipredator strategies, and resilience and adaptive responses. They also serve as essential models for studying broad genomic traits, such as evolutionary genome expansions and contractions, as they exhibit the widest range of genome sizes among all animal taxa and possess multiple mechanisms of genetic sex determination. Despite these features, genome sequencing of amphibians has significantly lagged behind that of other vertebrates, primarily due to the challenges of assembling their large, repeat-rich genomes and the relative lack of societal support. The emergence of long-read sequencing technologies, combined with advanced molecular and computational techniques that improve scaffolding and reduce computational workloads, is now making it possible to address some of these challenges. To promote and accelerate the production and use of amphibian genomics research through international coordination and collaboration, we launched the Amphibian Genomics Consortium (AGC, https://mvs.unimelb.edu.au/amphibian-genomics-consortium) in early 2023. This burgeoning community already has more than 282 members from 41 countries. The AGC aims to leverage the diverse capabilities of its members to advance genomic resources for amphibians and bridge the implementation gap between biologists, bioinformaticians, and conservation practitioners. Here we evaluate the state of the field of amphibian genomics, highlight previous studies, present challenges to overcome, and call on the research and conservation communities to unite as part of the AGC to enable amphibian genomics research to "leap" to the next level.

A new species of treefrog (Litoria: Pelodryadidae) from the karstic South-fold Mountains of New Guinea

The frog fauna of New Guinea is exceptionally diverse but very poorly known. Here we describe a new species of pelodryadid treefrog that is currently known only from two specimens from a single site in Hela Province in the highlands of Papua New Guinea. Genetic data show that the new species is closely related to the torrent-breeding species Litoria angiana (Boulenger, 1915) from which it can be readily distinguished by its more slender body and limbs, relatively long forelimbs, and aspects of body colouration and tuberculation. The type locality is on Gigira Ridge, a massive limestone spur extending off New Guinea's Central Cordillera and we hypothesise that the distinctive slender limbs and relatively long forelimbs of the species may be adaptations for clambering, either in complex montane forest habitats or potentially within karst. The ongoing discovery of rare and seemingly localised frog species in Melanesia emphasises that recent estimates of a regional anuran fauna in excess of 700 species that were derived from known candidate species are likely conservative.

A new species of narrow-banded Cyrtodactylus (Gekkonidae) from northern New Guinea

We describe a new species of Cyrtodactylus from the northern lowlands and foothills of mainland New Guinea. Cyrtodactylus mamberamo sp. nov. is distinguished from all other Melanesian Cyrtodactylus except C. aaroni and C. mimikanus by the combination of moderate size (max SVL <100 mm), widened subcaudals, dorsal pattern of numerous narrow light bands with dark-brown anterior borders, and a tripartite pore arrangement in males. It differs from these two most-similar species in details of colour pattern, scalation and the number of precloacal pores. Cyrtodactylus mamberamo sp. nov. occurs at elevations between 0-870 m above sea level (a.s.l.) across a wide area spanning the Mamberamo Basin and nearby regions. It co-occurs with at most one or two other congeners. Low Cyrtodactylus alpha diversity across Melanesia emphasises beta turnover as the key factor underpinning species richness in this genus. The new species brings the total number of recognised Melanesian Cyrtodactylus to 35, with the real total certain to be over 40 species.

Ecological Civilisation and Amphibian Sustainability through Reproduction Biotechnologies, Biobanking, and Conservation Breeding Programs (RBCs)

Intergenerational justice entitles the maximum retention of Earth's biodiversity. The 2022 United Nations COP 15, "Ecological Civilisation: Building a Shared Future for All Life on Earth", is committed to protecting 30% of Earth's terrestrial environments and, through COP 28, to mitigate the effects of the climate catastrophe on the biosphere. We focused this review on three core themes: the need and potential of reproduction biotechnologies, biobanks, and conservation breeding programs (RBCs) to satisfy sustainability goals; the technical state and current application of RBCs; and how to achieve the future potentials of RBCs in a rapidly evolving environmental and cultural landscape. RBCs include the hormonal stimulation of reproduction, the collection and storage of sperm and oocytes, and artificial fertilisation. Emerging technologies promise the perpetuation of species solely from biobanked biomaterials stored for perpetuity. Despite significant global declines and extinctions of amphibians, and predictions of a disastrous future for most biodiversity, practical support for amphibian RBCs remains limited mainly to a few limited projects in wealthy Western countries. We discuss the potential of amphibian RBCs to perpetuate amphibian diversity and prevent extinctions within multipolar geopolitical, cultural, and economic frameworks. We argue that a democratic, globally inclusive organisation is needed to focus RBCs on regions with the highest amphibian diversity. Prioritisation should include regional and international collaborations, community engagement, and support for RBC facilities ranging from zoos and other institutions to those of private carers. We tabulate a standard terminology for field programs associated with RBCs for publication and media consistency.

Infectious disease as a driver of declines and extinctions

Infectious disease is an important driver of extinctions and population declines. With a few exceptions, such as the fungal disease chytridiomycosis in frogs, disease is probably underestimated as a cause of both local and global extinction because it often co-occurs with other more overt drivers of extinction, and its signs can be easily overlooked. Here, we discuss issues around attributing extinction to infectious disease and overview key underlying factors. We then examine the extent to which anthropogenic influences, such as climate change, habitat destruction and exotic species introductions, are likely to lead to increased extinction risk in association with infectious disease. Finally, we discuss strategies to mitigate the threat of extinction due to infectious disease.

The first linkage map for Australo-Papuan Treefrogs (family: Pelodryadidae) reveals the sex-determination system of the Green-eyed Treefrog (Litoria serrata)

Amphibians represent a useful taxon to study the evolution of sex determination because of their highly variable sex-determination systems. However, the sex-determination system for many amphibian families remains unknown, in part because of a lack of genomic resources. Here, using an F1 family of Green-eyed Treefrogs (Litoria serrata), we produce the first genetic linkage map for any Australo-Papuan Treefrogs (family: Pelodryadidae). The resulting linkage map contains 8662 SNPs across 13 linkage groups. Using an independent set of sexed adults, we identify a small region in linkage group 6 matching an XY sex-determination system. These results suggest Litoria serrata possesses a male heterogametic system, with a candidate sex-determination locus on linkage group 6. Furthermore, this linkage map represents the first genomic resource for Australo-Papuan Treefrogs, an ecologically diverse family of over 220 species.

Redescription of Lepidodactylus flaviocularis (Squamata: Gekkonidae), with the description of a new species from Makira Island, Solomon Islands

Several species of geckos of the genus Lepidodactylus are endemic to the Solomon Islands and very poorly known. I redescribe one of these, L. flaviocularis, from Guadalcanal, based on examination of a second, newly obtained specimen and quantification of diagnostically useful features of the digits. I also describe a closely related new species from nearby Makira Island in the southern Solomon Islands. Both species are distinguished by their large number of undivided subdigital lamellae, extensive toe webbing, and a continuous row of enlarged precloacal/femoral scales. The new species is distinguished from L. flaviocularis by a number of scalational features and the color of the circumorbial scales. Both species are inhabitants of interior forest, and it remains uncertain whether they are naturally rare, rare due to interactions with invasive species, or simply have cryptic ecological habits, though the last seems most likely. Current evidence for both species is consistent with the taxon-cycle hypothesis, which posits ecological displacement to inland habitats of ancient island inhabitants by newer colonizers, but this remains to be critically tested. The limited pool of specimens available for both species necessitates assessing the IUCN conservation status of each as Data Deficient.

Two new species of green treefrogs (Pelodryadidae: Litoria) from the northern slopes of Papua New Guinea's Central Cordillera

We describe two new species of moderate-sized (male body length 26.5-29.8 mm and 41.0 mm), predominantly green treefrogs in the genus Litoria from hill forest on the northern slopes of Papua New Guinea's Central Cordillera. Phylogenetic analysis of mitochondrial ND4 nucleotide sequences shows that the first species is related to Litoria iris (Tyler) and its allies. It is morphologically most similar to Litoria mystax, a small green treefrog known only from the holotype that was described more than 100 years ago from the north coast of western New Guinea but differs from that species in having longer legs and a broader head. The second species is closest to Litoria gasconi, a species known only from the foothills of the Foja Mountains in Papua Province, Indonesian New Guinea, and the Prince Alexander Mountains in northern Papua New Guinea. It has a net average sequence divergence of 10% from L. gasconi and can be distinguished morphologically from it and from other pelodryadids by the presence of a striking pattern of spots and blotches on the ventral surfaces and on the hidden surfaces of the limbs. These descriptions add to the rapidly increasing known diversity of frogs in hill and lower montane forest, habitats that support the most diverse frog communities on mainland New Guinea.

Five new species of the pelodryadid genus Litoria Tschudi from the southern versant of Papua New Guinea’s Central Cordillera, with observations on the diversification of reproductive strategies in Melanesian treefrogs

New Guinea has the most diverse insular frog fauna in the world, and rates of species discovery and description have increased rapidly in the last two decades. Pelodryadid treefrogs are the second most diverse family of anurans on the island but their taxonomy, relationships, and especially ecology remain poorly documented. Based on differences in morphology, advertisement calls (where available) and phylogenetic analyses of a 787 base pair alignment from the mitochondrial ND4 gene and flanking tRNA, we describe five new species of small treefrogs from hill and lower montane forests in the high rainfall belt that straddles the southern versant of Papua New Guinea’s Central Cordillera. Three of these species are known only from forest growing on karst substrates, adding to the growing number of herpetofauna species currently known only from the extensive karst habitats of Papua New Guinea’s South-fold Mountains. We also describe the arboreal breeding strategies of two of the new species, and report obligate treehole (phytotelm) breeding in New Guinean frogs for the first time. The new phytotelm–breeding species has juveniles with colour and patterning that closely resemble bird droppings, suggesting defensive mimicry or masquerade. A preliminary phylogeny suggests that arboreal-breeding frogs do not form a monophyletic group and that arboreal breeding has evolved multiple times within the New Guinean pelodryadid radiation. A further striking feature of the phylogeny is poor support for most basal nodes in the most diverse radiation of Melanesian Pelodryadidae, suggesting rapid ecological diversification and speciation, potentially following colonisation from Australia and/or mountain uplift. These new taxa and observations highlight previously unrecognised ecological and reproductive diversity in the Melanesian Pelodryadidae.  

Another giant species of the microhylid frog genus Cophixalus Boettger, 1892 from the mountains of Papua New Guinea and first records of procoracoids in the genus

A new arboreal species of the microhylid genus Cophixalus Boettger, 1892 is described from montane rainforest on Papua New Guinea’s central cordillera. With a male SUL exceeding 44.0 mm, the new species is among the largest members of the genus; the only other Papuan species known to reach this size is C. riparius Zweifel, 1962. The new species differs from C. riparius in a small number of mensural characters and by its distinct advertisement call, a single explosive ‘bark’ uttered singly or in rapid series. In contrast, calls of C. riparius recorded near the type locality are a series of drawn out, rasping croaks. Calls of the two species are analysed and compared. The two species also appear to have different ecologies, with the new species found only high in trees, while C. riparius is often encountered in vegetation on or near the forest floor. Examination of osteological features revealed the presence of cartilaginous procoracoids in both species, representing the first records of procoracoids in the speciose genus Cophixalus. Lack of procoracoids is traditionally considered an important diagnostic character for defining Cophixalus but both species also lack clavicles, a character considered diagnostic for Cophixalus and a key feature distinguishing the genus from the closely related Oreophryne Boettger, 1895. Because preliminary published genetic data indicate that they are nested within Cophixalus, we retain both species in that genus until a comprehensive molecular phylogeny of Cophixalus and related genera, particularly Oreophryne, is completed.

A new species of torrent-breeding treefrog (Pelodryadidae: Litoria) from the mountains of Papua, Indonesia, with new records and observations of Litoria dorsivena (Tyler, 1968)

The mountains of New Guinea are home to species-rich but poorly understood communities of stream or torrent-breeding pelodryadid treefrogs. Here we describe a new species of moderately sized torrent-breeding Litoria from the mountains of Papua Province, Indonesia. The new species is most similar to Litoria dorsivena but differs from that species in aspects of body size, skin texture and especially the shape of the snout. Based on recent collections, we also present new data on the distribution and colour in life of L. dorsivena. Both species show marked sexual size dimorphism when compared to most other pelodryadid treefrogs, and the colour pattern of the new species may also vary between males and females. The torrent-breeding treefrogs of New Guinea remain poorly known and, given declines of ecologically similar pelodryadids in Australia, should be a priority group for taxonomic research and population monitoring.

A new species of insular treefrog in the Litoria thesaurensis species group from the Nakanai Mountains, New Britain, Papua New Guinea

The Islands of East Melanesia have a unique and highly endemic frog fauna derived entirely from overseas colonisation events. Within East Melanesia New Britain is a notable centre of frog diversity and endemism, with at least 15 endemic species, mostly in the ceratobatrachid genus Cornufer. Here we describe the first endemic pelodryadid treefrog from New Britain. The new species is a member of the Litoria thesaurensis species group but can be distinguished from near relatives by aspects of body size, webbing extent, bone pigmentation and male advertisement call. The two known specimens of the new species were collected in Hill Forest on karst basement in the Nakanai Mountains in East New Britain. The new species provides new evidence of diversification of insular PelodrydidaePelodrydidae, and reinforces New Britain, and especially the predominantly karst Nakanai mountains, as a hotspot of frog diversity in East Melanesia. In light of high rates of forest loss and conversion New Britain is also a region of significant conservation concern.