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  1. Fulltext Additions to the herpetofauna of Pasoh Forest Reserve, Negeri Sembilan, Peninsular Malaysia
    Chan, Kin Onn, Mohd. Shahfiz Azman, Nor Azlin, Pan, Khang Aun
    Trop Life Sci Res, 2009;20(1):-.
    MyJurnal
    A survey was carried out at the Pasoh Forest Reserve from 13–19 December, 2007 and 20–24 January, 2008, to inventory the herpetofauna contained therein. A total of 23 species of reptiles and amphibians were collected during this survey, five of which have not previously been recorded in the Pasoh Forest Reserve. An updated checklist which incorporates findings from previous studies is presented.
  2. Fulltext To split or not to split? Multilocus phylogeny and molecular species delimitation of southeast Asian toads (family: Bufonidae)
    Chan KO, Grismer LL
    BMC Evol. Biol., 2019 04 25;19(1):95.
    PMID: 31023232 DOI: 10.1186/s12862-019-1422-3
    BACKGROUND: Recent studies have demonstrated that Bayesian species delimitation based on the multispecies coalescent model can produce inaccurate results by misinterpreting population splits as species divergences. An approach based on the genealogical divergence index (gdi) was shown to be a viable alternative, especially for delimiting allopatric populations where gene flow is low. We implemented these analyses to assess species boundaries in Southeast Asian toads, a group that is understudied and characterized by numerous unresolved species complexes.

    RESULTS: Multilocus phylogenetic analyses showed that deep evolutionary relationships including the genera Sigalegalephrynus, Ghatophryne, Parapelophryne, Leptophryne, Pseudobufo, Rentapia, and Phrynoides remain unresolved. Comparison of genetic divergences revealed that intraspecific divergences among allopatric populations of Pelophyrne signata (Borneo vs. Peninsular Malaysia), Ingerophrynus parvus (Peninsular Malaysia vs. Myanmar), and Leptophryne borbonica (Peninsular Malaysia, Java, Borneo, and Sumatra) are consistent with interspecific divergences of other Southeast Asian bufonid taxa. Conversely, interspecific divergences between Pelophryne guentheri/P. api, Ansonia latiffi/A. leptopus, and I. gollum/I. divergens were low (

  3. Reappraisal of the Javanese Bullfrog complex, Kaloula baleata (Müller, 1836) (Amphibia: Anura: Microhylidae), reveals a new species from Peninsular Malaysia
    Chan KO, Grismer LL, Brown RM
    Zootaxa, 2014;3900(4):569-80.
    PMID: 25543757 DOI: 10.11646/zootaxa.3900.4.7
    A new species of Narrow-mouthed frog of the genus Kaloula is described from northern Peninsular Malaysia. Kaloula latidisca sp. nov. is genetically and morphologically most similar to K. baleata and K. indochinensis but differs from those and other congeners by the unique combination of the following characters: (1) adult males SVL 49.2-56.2 mm (x̅=53.5 ± 3.0; N=4); (2) finger tips expanded into large, transversely expanded discs (disc width 2.8-3.1 mm, x̅=3.0 ± 0.1); (3) inner metatarsal tubercle large, oval, distinctly raised, slightly shorter than first toe; (4) three subarticular tubercles on fourth toe; (5) toe webbing formula: I 1-2 II 1-3 III 2-3.5 IV 4-2 V; and (6) yellow to orange irregularly shaped patch on the axillary, inguinal and posterior region of thigh.
  4. Comprehensive multi-locus phylogeny of Old World tree frogs (Anura: Rhacophoridae) reveals taxonomic uncertainties and potential cases of over- and underestimation of species diversity
    Chan KO, Grismer LL, Brown RM
    Mol Phylogenet Evol, 2018 10;127:1010-1019.
    PMID: 30030179 DOI: 10.1016/j.ympev.2018.07.005
    The family Rhacophoridae is one of the most diverse amphibian families in Asia, for which taxonomic understanding is rapidly-expanding, with new species being described steadily, and at increasingly finer genetic resolution. Distance-based methods frequently have been used to justify or at least to bolster the recognition of new species, particularly in complexes of "cryptic" species where obvious morphological differentiation does not accompany speciation. However, there is no universally-accepted threshold to distinguish intra- from interspecific genetic divergence. Moreover, indiscriminant use of divergence thresholds to delimit species can result in over- or underestimation of species diversity. To explore the range of variation in application of divergence scales, and to provide a family-wide assessment of species-level diversity in Old-World treefrogs (family Rhacophoridae), we assembled the most comprehensive multi-locus phylogeny to date, including all 18 genera and approximately 247 described species (∼60% coverage). We then used the Automatic Barcode Gap Discovery (ABGD) method to obtain different species-delimitation schemes over a range of prior intraspecific divergence limits to assess the consistency of divergence thresholds used to demarcate current species boundaries. The species-rich phylogeny was able to identify a number of taxonomic errors, namely the incorrect generic placement of Chiromantis inexpectatus, which we now move to the genus Feihyla, and the specific identity of Rhacophorus bipunctatus from Peninsular Malaysia, which we tentatively reassign to R. rhodopus. The ABGD analysis demonstrated overlap between intra- and interspecific divergence limits: genetic thresholds used in some studies to synonymize taxa have frequently been used in other studies to justify the recognition of new species. This analysis also highlighted numerous groups that could potentially be split or lumped, which we earmark for future examination. Our large-scale and en bloc approach to species-level phylogenetic systematics contributes to the resolution of taxonomic uncertainties, reveals possible new species, and identifies numerous groups that require critical examination. Overall, we demonstrate that the taxonomy and evolutionary history of Old-World tree frogs are far from resolved, stable or adequately characterized at the level of genus, species, and/or population.
  5. The Artefactual Branch Effect and Phylogenetic Conflict: Species Delimitation with Gene Flow in Mangrove Pit Vipers (Trimeresurus purpureomaculatus-erythrurus complex)
    Chan KO, Mulcahy DG, Anuar S
    Syst Biol, 2023 Jul 21.
    PMID: 37478480 DOI: 10.1093/sysbio/syad043
    Mangrove pit vipers of the Trimeresurus purpureomaculatus-erythrurus complex are the only species of viper known to inhabit mangroves. Despite serving integral ecological functions in mangrove ecosystems, the evolutionary history, distribution, and species boundaries of mangrove pit vipers remain poorly understood, partly due to overlapping distributions, confusing phenotypic variations, and the lack of focused studies. Here, we present the first genomic study on mangrove pit vipers and introduce a robust hypothesis-driven species delimitation framework that considers gene flow and phylogenetic uncertainty in conjunction with a novel application of a new class of speciation-based delimitation model implemented through the program Delineate.Our results showed that gene flow produced phylogenetic conflict in our focal species and substantiates the artefactual branch effect where highly admixed populations appear as divergent non-monophyletic lineages arranged in a stepwise manner at the basal position of clades. Despite the confounding effects of gene flow, we were able to obtain unequivocal support for the recognition of a new species based on the intersection and congruence of multiple lines of evidence. This study demonstrates that an integrative hypothesis-driven approach predicated on the consideration of multiple plausible evolutionary histories, population structure/differentiation, gene flow, and the implementation of a speciation-based delimitation model can effectively delimit species in the presence of gene flow and phylogenetic conflict.
  6. A new species of upland Stream Toad of the genus Ansonia Stoliczka, 1870 (Anura: Bufonidae) from northeastern Peninsular Malaysia
    Chan KO, Wood PL, Anuar S, Muin MA, Quah ES, Sumarli AX
    Zootaxa, 2014;3764:427-40.
    PMID: 24870645 DOI: 10.11646/zootaxa.3764.4.3
    A new species of Ansonia is described based on genetic and morphological differentiation. Ansonia lumut sp. nov. is most closely related to three other Peninsular Malaysian species, A. penangensis, A. malayana, and A. jeetsukumarani but differs from these and other congeners by at least 6.9% sequence divergence at the 12S, 16S rRNA and t-RNA-val genes and the following combination of morphological characters: (1) SVL 21.0-23.6 mm in males, 27.7-31.6 mm in females; (2) first finger shorter than second; (3) interorbital and tarsal ridges absent; (4) light interscapular spot absent; (5) presence of large, yellow rictal tubercle; (6) dorsum black with greenish-yellow reticulations; (7) flanks with small yellow spots; (8) fore and hind limbs with yellow cross-bars; and (9) venter light gray with fine, white spotting.
  7. Fulltext Molecular Systematics of the Firefly Genus Luciola (Coleoptera: Lampyridae: Luciolinae) with the Description of a New Species from Singapore
    Jusoh WFA, Ballantyne L, Chan SH, Wong TW, Yeo D, Nada B, et al.
    Animals (Basel), 2021 Mar 04;11(3).
    PMID: 33806564 DOI: 10.3390/ani11030687
    The firefly genus Luciola sensu McDermott contains 282 species that are distributed across major parts of Asia, Europe, Africa, Australia, and the Pacific islands. Due to phenotypic similarities, species identification using external morphological characters can be unreliable for this group. Consequently, decades of piecemeal taxonomic treatments have resulted in numerous erroneous and contentious classifications. Furthermore, our understanding of the group's evolutionary history is limited due to the lack of a robust phylogenetic framework that has also impeded efforts to stabilize its taxonomy. Here, we constructed molecular phylogenies of Luciola and its allies based on combined mitogenomes and Cytochrome c oxidase subunit 1 (COX1) sequences including a newly sequenced mitogenome of an unidentified taxon from Singapore. Our results showed that this taxon represents a distinct and hitherto undescribed evolutionary lineage that forms a clade with L. filiformis from Japan and L. curtithorax from China. Additionally, the Singaporean lineage can be differentiated from other congeners through several external and internal diagnostic morphological characters, and is thus described herein as a new species. Our phylogeny also strongly supported the paraphyly of Luciola with regard to L. cruciata and L. owadai, which were inferred to be more closely related to the genus Aquatica as opposed to other members of Luciola sensu stricto. The genus Hotaria was inferred as a derived clade within Luciola (sister to L. italica), supporting its status as a subgenus of Luciola instead of a distinct genus. This is the first time since 1909 that a new species of luminous firefly has been discovered in Singapore, highlighting the need for continued biodiversity research, even in small, well-studied and highly developed countries, such as Singapore.
  8. Fulltext Preliminary checklist of the herpetofauna of Pulau Besar, Melaka, Malaysia
    Chan KO, Grismer LL, Wood, PL, Grismer JL, Ahmad N
    Trop Life Sci Res, 2009;20(1):-.
    MyJurnal
    A herpetological survey was conducted at Pulau Besar, Melaka from 10 to 12 June 2008, resulting in the discovery of five species of amphibians, nine species of lizards (including one new species of the gekkonid Cyrtodactylus) and one snake species. This report constitutes the first checklist of the herpetofauna of Pulau Besar and the Water Islands Archipelago.
  9. A taxonomic revision of Asthenodipsas malaccana Peters, 1864 (Squamata: Pareidae) with a description of a new species from Borneo
    Quah ESH, Grismer LL, Lim KKP, Anuar MSS, Chan KO
    Zootaxa, 2020 Jan 28;4729(1):zootaxa.4729.1.1.
    PMID: 32229869 DOI: 10.11646/zootaxa.4729.1.1
    A reappraisal of the taxonomic status of the Dark-necked Slug Snake (Asthenodipsas malaccana Peters, 1864) across its range revealed that populations from Borneo are not conspecific with true A. malaccana from the Thai-Malay Peninsula and Sumatra, and is therefore described herein as new. Asthenodipsas borneensis sp. nov. can be distinguished from A. malaccana and other congeners by the absence of a preocular and suboculars, seven or eight supralabials with 3rd and 4th in contact with orbit, 4-7 infralabials with 2nd or 3rd pair in contact, two pairs of posterior inframaxillaries, 15/15/15 rows of dorsal scales, presence of sharp vertebral keel, divided subcaudals, maximum recorded SVL=441 mm, 166-179 ventrals, 35-48 subcaudals, head white to greyish brown and dorsum beige to orange-brown with a conspicuous dark-brown or black patch on the neck followed by multiple, narrow, vertical, dark bands along the rest of the body and tail. This discovery adds to a growing number of new slug snake species recently described from Southeast Asia and highlights the underestimated diversity in this family, especially in Borneo. Taxonomic revisions of the reptiles and amphibians of Borneo are still needed before the true diversity of the island and the relationships of the various taxa can be fully understood.
  10. Species delimitation with gene flow: A methodological comparison and population genomics approach to elucidate cryptic species boundaries in Malaysian Torrent Frogs
    Chan KO, Alexander AM, Grismer LL, Su YC, Grismer JL, Quah ESH, et al.
    Mol Ecol, 2017 Oct;26(20):5435-5450.
    PMID: 28802073 DOI: 10.1111/mec.14296
    Accurately delimiting species boundaries is a nontrivial undertaking that can have significant effects on downstream inferences. We compared the efficacy of commonly used species delimitation methods (SDMs) and a population genomics approach based on genomewide single-nucleotide polymorphisms (SNPs) to assess lineage separation in the Malaysian Torrent Frog Complex currently recognized as a single species (Amolops larutensis). First, we used morphological, mitochondrial DNA and genomewide SNPs to identify putative species boundaries by implementing noncoalescent and coalescent-based SDMs (mPTP, iBPP, BFD*). We then tested the validity of putative boundaries by estimating spatiotemporal gene flow (fastsimcoal2, ABBA-BABA) to assess the extent of genetic isolation among putative species. Our results show that the A. larutensis complex runs the gamut of the speciation continuum from highly divergent, genetically isolated lineages (mean Fst  = 0.9) to differentiating populations involving recent gene flow (mean Fst  = 0.05; Nm  > 5). As expected, SDMs were effective at delimiting divergent lineages in the absence of gene flow but overestimated species in the presence of marked population structure and gene flow. However, using a population genomics approach and the concept of species as separately evolving metapopulation lineages as the only necessary property of a species, we were able to objectively elucidate cryptic species boundaries in the presence of past and present gene flow. This study does not discount the utility of SDMs but highlights the danger of violating model assumptions and the importance of carefully considering methods that appropriately fit the diversification history of a particular system.
  11. A new species of karst-adapted Cnemaspis Strauch, 1887 (Squamata: Gekkonidae) from a threatened karst region in Pahang, Peninsular Malaysia
    Grismer LL, Wood PL, Mohamed M, Chan KO, Heinz HM, Sumarli AS, et al.
    Zootaxa, 2013;3746:463-72.
    PMID: 25113489 DOI: 10.11646/zootaxa.3746.3.5
    A new species of karst-adapted gekkonid lizard of the genus Cnemaspis Strauch is described from Gua Gunting and Gua Goyang in a karst region of Merapoh, Pahang, Peninsular Malaysia whose unique limestone formations are in immediate danger of being quarried. The new species differs from all other species of Cnemaspis based on its unique suite of morphological and color pattern characters. Its discovery underscores the unique biodiversity endemic to karst regions and adds to a growing list of karst-adapted reptiles from Peninsular Malaysia. We posit that new karst-adapted species endemic to limestone forests will continue to be discovered and these regions will harbor a significant percentage of Peninsular Malaysia's biodiversity and thusly should be conserved rather than quarried.
  12. Fulltext A new species of pit-viper from the Ayeyarwady and Yangon regions in Myanmar (Viperidae, Trimeresurus)
    Chan KO, Anuar S, Sankar A, Law IT, Law IS, Shivaram R, et al.
    Zookeys, 2023;1186:221-234.
    PMID: 38312859 DOI: 10.3897/zookeys.1186.110422
    In a genomic study by Chan and colleagues, pit-vipers of the Trimeresuruserythrurus-purpureomaculatus complex from the Ayeyarwady and Yangon regions in Myanmar were demonstrated to be a distinct species based on robust population genetic and species delimitation analyses. Here, we provide morphological characterizations and a formal description of those populations as a new species. The new species, Trimeresurusayeyarwadyensissp. nov., is most closely related to T.erythrurus and T.purpureomaculatus and shares morphological characteristics with both of those species. Some specimens of T.ayeyarwadyensissp. nov. have green dorsal coloration and no distinct dorsal blotches (a trait shared with T.erythrurus but not T.purpureomaculatus), while others have dark dorsal blotches (a trait shared with T.purpureomaculatus but not T.erythrurus). The distinct evolutionary trajectory of the new species, coupled with the lack of obvious morphological differentiation, represents a classic example of the cryptic nature of species commonly found in the Trimeresurus group of Asian pit-vipers and underscores the need for data-rich analyses to verify species' boundaries more broadly within this genus.
  13. Multilocus phylogeny of Bornean Bent-Toed geckos (Gekkonidae: Cyrtodactylus) reveals hidden diversity, taxonomic disarray, and novel biogeographic patterns
    Davis HR, Chan KO, Das I, Brennan IG, Karin BR, Jackman TR, et al.
    Mol Phylogenet Evol, 2020 06;147:106785.
    PMID: 32135306 DOI: 10.1016/j.ympev.2020.106785
    The gekkonid genus Cyrtodactylus is a highly diverse group of lizards (280 + species), which covers an expansive geographic range. Although this genus has been the focus of many taxonomic and molecular systematic studies, species on the Southeast Asian island of Borneo have remained understudied, leading to an unclear evolutionary history with cascading effects on taxonomy and biogeographic inferences. We assembled the most comprehensive multilocus Bornean dataset (one mitochondrial and three nuclear loci) that included 129 novel sequences and representatives from each known Cyrtodactylus species on the island to validate taxonomic status, assess species diversity, and elucidate biogeographic patterns. Our results uncovered a high proportion of cryptic diversity and revealed numerous taxonomic complications, especially within the C. consobrinus, C. malayanus, and C. pubisulcus groups. Comparisons of pairwise genetic distances and a preliminary species delimitation analysis using the Automatic Barcode Gap Discovery (ABGD) method demonstrated that some wide-ranging species on Borneo likely comprise multiple distinct and deeply divergent lineages, each with more restricted distributional ranges. We also tested the prevailing biogeographic hypothesis of a single invasion from Borneo into the Philippines. Our analyses revealed that Philippine taxa were not monophyletic, but were likely derived from multiple separate invasions into the geopolitical areas comprising the Philippines. Although our investigation of Bornean Cyrtodactylus is the most comprehensive to-date, it highlights the need for expanded taxonomic sampling and suggests that our knowledge of the evolutionary history, systematics, and biogeography of Bornean Cyrtodactylus is far from complete.
  14. Fulltext Author Correction: Ongoing declines for the world's amphibians in the face of emerging threats
    Luedtke JA, Chanson J, Neam K, Hobin L, Maciel AO, Catenazzi A, et al.
    Nature, 2024 Jan;625(7993):E2.
    PMID: 38040869 DOI: 10.1038/s41586-023-06851-6
  15. Fulltext Ongoing declines for the world's amphibians in the face of emerging threats
    Luedtke JA, Chanson J, Neam K, Hobin L, Maciel AO, Catenazzi A, et al.
    Nature, 2023 Oct;622(7982):308-314.
    PMID: 37794184 DOI: 10.1038/s41586-023-06578-4
    Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action1,2. Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment3,4. Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the International Union for Conservation of Nature Red List of Threatened Species. We find that amphibians are the most threatened vertebrate class (40.7% of species are globally threatened). The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders and in the Neotropics. Disease and habitat loss drove 91% of status deteriorations between 1980 and 2004. Ongoing and projected climate change effects are now of increasing concern, driving 39% of status deteriorations since 2004, followed by habitat loss (37%). Although signs of species recoveries incentivize immediate conservation action, scaled-up investment is urgently needed to reverse the current trends.
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