Impacts of the Toba eruption and montane forest expansion on diversification in Sumatran parachuting frogs (Rhacophorus).

Catastrophic events, such as volcanic eruptions, can have profound impacts on the demographic histories of resident taxa. Due to its presumed effect on biodiversity, the Pleistocene eruption of super-volcano Toba has received abundant attention. We test the effects of the Toba eruption on the diversification, genetic diversity, and demography of three co-distributed species of parachuting frogs (Genus Rhacophorus) on Sumatra. We generate target-capture data (~950 loci and ~440,000 bp) for three species of parachuting frogs and use these data paired with previously generated double digest restriction-site associated DNA (ddRADseq) data to estimate population structure and genetic diversity, to test for population size changes using demographic modelling, and to estimate the temporal clustering of size change events using a full-likelihood Bayesian method. We find that populations around Toba exhibit reduced genetic diversity compared with southern populations, and that northern populations exhibit a shift in effective population size around the time of the eruption (~80 kya). However, we infer a stronger signal of expansion in southern populations around ~400 kya, and at least two of the northern populations may have also expanded at this time. Taken together, these findings suggest that the Toba eruption precipitated population declines in northern populations, but that the demographic history of these three species was also strongly impacted by mid-Pleistocene forest expansion during glacial periods. We propose local rather than regional effects of the Toba eruption, and emphasize the dynamic nature of diversification on the Sunda Shelf.

Phylogeography of montane dragons could shed light on the history of forests and diversification processes on Sumatra.

Biogeographical evidence, both, for and against the "regional endemism paradigm" hypothesis has been uncovered across the Greater Sunda Region (Sundaland) of Southeast Asia. Additionally, there are competing hypotheses regarding how Pleistocene forests may have impacted biological patterns and processes in Sumatra. Using montane agamid lizards from Sumatra, we derived and analyzed a phylogenetic dataset, genetic divergence estimates, and contemporary distributional patterns among species. We tested whether (1) Sumatra's highland Draconinae diversification fits the regional endemism paradigm hypothesis and (2) Draconinae phylogeography provides biological evidence for Pleistocene forest extent at various points in history. Our results suggest in situ diversification was the main driver behind montane Draconinae lizard diversification in Sumatra, rejecting the "regional endemism paradigm". Contemporary distribution of endemic species and their genetic relationships may potentially provide biologicalevidence for determining more precise elevational lower limits of montane forests during the Pleistocene epoch. Our data suggests montane forests did not retreat more than 700-750 m during glacial maxima because lower retreating forests would have become interconnected, allowing for widespread dispersal, exchange of gene flow and sympatric distributions contemporarily. To the contrary, our divergence estimates show that cloud forest dragons have been isolated for millions of years, suggesting there may have been a continuous disconnect between some areas, predating the Pleistocene. There may also be other ecological and evolutionary factors that impacted Draconinae distributions, such as competition, making this an excellent system for testing questions regarding montane biogeography. Additionally, we provide the first phylogeny for a wide range of Sundaland agamid species and identify some biogeographic pressures that may have triggered montane Draconinae diversification in Sumatra.

Diversification of bent-toed geckos (Cyrtodactylus) on Sumatra and west Java.

Complex geological processes often drive biotic diversification on islands. The islands of Sumatra and Java have experienced dramatic historical changes, including isolation by marine incursions followed by periodic connectivity with the rest of Sundaland across highland connections. To determine how this geological history influenced island invasions, we investigated the colonization history and diversification of bent-toed geckos (genus Cyrtodactylus) on Sumatra and west Java. We used mitochondrial and nuclear sequence data to explore species boundaries, estimate phylogenetic relationships and divergence times, and to reconstruct ancestral range evolution. We found that Sumatran and Javan Cyrtodactylus were closely related to species from the Thai-Malay Peninsula, rather than from Borneo, and that Cyrtodactylus most likely dispersed to Sumatra three times during the late Oligocene and early Miocene. Similarly, Cyrtodactylus invaded west Java from Sumatra once in the early Miocene. Our results suggest that despite isolation by marine incursions during much of the Miocene, Cyrtodactylus dispersed to and from Sumatra and west Java likely via land bridges, and that in situ diversification occurred several times on Sumatra.

Synchronous diversification of parachuting frogs (Genus Rhacophorus) on Sumatra and Java.

Geological and climatological processes can drive the synchronous diversification of co-distributed species. The islands of Sumatra and Java have experienced complex geological and climatological histories, including extensive sea-level changes and the formation of valleys between northern, central, and southern components of the Barisan Mountain Range, which may have promoted diversification of their resident species. We investigate diversification on these islands using 13 species of the parachuting frog genus Rhacophorus. We use both mitochondrial and nuclear sequence data, along with genome-wide SNPs to estimate phylogenetic structure and divergence times, and to test for synchronous diversification. We find support for synchronous divergence among sister-species pairs from Sumatra and Java ∼9 Ma, as well as of populations of four co-distributed taxa on Sumatra ∼5.6 Ma. We found that sister species diverged in allopatry on Sumatra and conclude that divergence on Sumatra and Java was affected by sea-level fluctuations that promoted isolation in allopatry.

A new species of the Cyrtodactylusquadrivirgatus complex (Chordata, Reptilia, Squamata, Gekkonidae) from Sumatra Barat, Indonesia.

Among the six species of Cyrtodactylus occurring in Sumatra, two species were described based on non-Sumatran type series, C.consobrinus and C.quadrivirgatus. The latter species was described originally from Thailand thus the wider distribution in Sumatra should be clarified taxonomically. Cyrtodactylusquadrivirgatus from Sumatra Barat was examined using both morphology and the Natrium Dehydrogenase Subunit 2 (ND2) gene to clarify its taxonomic status and phylogenetic placement. It was found that these specimens form a sister clade to all other species of the sworderi group from Peninsular Malaysia and the genetic distance ranges from 20-24.3%. This subset is herein described as a new species. The new species is readily distinguished from C.quadrivirgatus and other Sumatran species by a combination of characters: small size SVL 37.5-53.78 mm; longitudinal rows of dorsal tubercles 16-19; paravertebral tubercles 31-41; ventral scales 32-43; 24-49 enlarged precloacal and femoral scales; precloacal pores rarely present; no precloacal depression; two postcloacal tubercles on each side; 14-19 subdigital lamellae on forth toe; 9-15 supralabial scales; 9-12 infralabial scales; three or four internasal scales; and 3-6 gular scales that border the first pair of postmental scales. This work underscores the importance of clarifying widely distributed species for taxonomic validation.

A taxonomic revision of Boiga multomaculata (Boie, 1827) and B. ochracea (Theobald, 1868), with the description of a new subspecies (Squamata, Serpentes, Colubridae).

The analyses of molecular genetic data (mtDNA markers 16S, ND4, CYTB, and the nuclear marker c-mos) provided evidence that the Asian cat snake taxa Boiga multomaculata and B. ochracea actually represent a single species. They form mixed clades of low intraclade genetic differentiation. This evidence for conspecificy is supported by the lack of differentiation in all examined pholidotic and morphometric characters. Therefore, we formally place Dipsas ochracea Theobald, 1868 in the synonymy of Dipsas multomaculata Boie, 1827. We provide a summary of the tangled taxonomic history of the taxa involved in this study. Also, we resurrect Dipsadomorphus stoliczkae Wall, 1909 from synonymy of B. ochracea, for specimens exhibiting 21 midbody dorsal scale rows. Boiga stoliczkae is found in the Himalayas north and west of the Brahmaputra valley. Finally, based on the detection of historical genetic lineages within the newly defined species Boiga multomaculata we recognize three subspecies: Boiga multomaculata multomaculata (Boie, 1827), Boiga multomaculata ochracea (Theobald, 1868), and Boiga multomaculata septentrionalis n. ssp. which is distributed in northern Myanmar and Assam and Nagaland, India. We designate BMNH 1946.1.2.60 (1) as neotype of Dipsas ochracea Theobald, (2) as lectotype of D. ochraceus Günther, and (3) as lectotype of Boiga ochracea walli Smith, thereby making these names objective synonyms. Finally, we designate BMNH 94.12.31.55 as lectotype of Dipsadomorphus stoliczkae Wall.

Common but ignored: a new species of Cyrtodactylus (Chordata, Reptilia, Squamata, Gekkonidae) from lowland Sumatra Barat, Indonesia.

The lowland region of Sumatra Barat has received little attention in previous biodiversity studies. Past studies have mainly focused on highland habitat and conservation areas. However, many populations of Cyrtodactylus in the lowland habitats of Sumatra Barat were not correctly identified. A phylogenetic tree based on the NADH dehydrogenase subunit 2 (ND2) gene showed that the lowland Sumatran population is the sister group of the Malaysian lowland species, C.semenanjungensis, together nesting within the agamensis group. The genetic divergence within the Sumatra Barat population is 0-4.2% and 18.3-20% to C.semenanjungensis. Further examination of morphological characters revealed that they differed from the sister clade and other Sumatran Cyrtodactylus members by a unique combination of characters such as absence of tubercle on brachium, presence of tubercle on ventrolateral fold, 32-41 paravertebral tubercles, 38-46 ventral scales, enlarged femoral scales, presence of precloacofemoral pores and 22-23 subdigital lamellae under fourth toe. Based on the morphological and molecular evidence, the lowland Sumatran population is herein described as a new species, increasing the number of species in Sumatra to seven. More comprehensive and intensive sampling efforts would most likely yield further discoveries in the group of Sumatran Cyrtodactylus in the near future.

A Checklist of the Herpetofauna of Nusa Kambangan Island, Central Java, Indonesia.

An inventory of herpetofauna species from western part of Nusa Kambangan Island, Central Java, Indonesia, is presented. There are 43 herpetofauna species reported (16 amphibians and 27 reptiles). This study confirmed new distribution record and list some of threatened species. In light of the imminent human disturbances on Nusa Kambangan Island, a conservation plan is urgently needed.

Postmating isolation and evolutionary relationships among Fejervarya species from Lesser Sunda, Indonesia and other Asian countries revealed by crossing experiments and mtDNA Cytb sequence analyses.

To evaluate the degree of postmating isolation and the evolutionary relationships among frog species in the genus Fejervarya from Indonesia (Lesser Sunda), Bangladesh, China, and Japan, crossing experiments and molecular phylogenetic analyses were carried out. Crossing experiments revealed that reciprocal hybrids among F. iskandari, F. verruculosa, and F. sp. large type and between F. multistriata and F. kawamurai are viable through metamorphosis, while those between the F. iskandari group and F. limnocharis group were completely or partially inviable at the tadpole stage and those between Southeast Asian and South Asian Fejervarya groups were completely inviable at the embryonic stage. The mature reciprocal hybrids between F. iskandari and F. verruculosa from Lesser Sunda, Indonesia, showed some degree of abnormality in spermatogenesis. In phylogenetic analyses based on mtDNA Cytb sequences, F. iskandari formed a sister clade with F. verruculosa from Lesser Sunda, Indonesia, with 8.1% sequence divergence. F. multistriata from China formed a clade with populations of F. limnocharis in Thailand, Malaysia, and Indonesia (topotype), and these taxa showed sister relationships to F. kawamurai from Japan with 8.9% sequence divergence. Fejervarya sp. small type from Bangladesh formed a clade with the other South Asian members of the Fejervarya group and formed a sister clade with the Southeast Asian Fejervarya group, with 23.1% sequence divergence in the Cytb gene. These results showed that the degree of postmating isolation reflects molecular phylogenetic relationships and that F. iskandari and F. verruculosa from Indonesia (Lesser Sunda) are reproductively isolated by abnormalities in spermatogenesis and show genetic differentiation.

Taxonomic status of three types of Fejervarya cancrivora from Indonesia and other Asian countries based on morphological observations and crossing experiments.

Although the crab-eating frog Fejervarya cancrivora is one of the most widely distributed species in Asian region, taxonomic relationships among different populations remain unclarified. In this study, we attempted to elucidate the taxonomic status of F. cancrivora from Indonesian and other Asian populations. Five populations of F. cancrivora from Selangor (Malaysia), Cianjur (Java, Indonesia), Trat (Thailand), Khulna (Bangladesh), and Makassar (Sulawesi, Indonesia) were morphologically observed and subjected to crossing experiments. Principal component and clustering analyses revealed that these five populations could be organized into three groups corresponding to three observed morphological types: a Selangor and Cianjur group (large-type), a Trat and Khulna group (mangrove-type), and a Makassar group (Sulawesi-type). The limited crossing experiments revealed that hybrids between Selangor females and Cianjur and Trat males developed normally, whereas hybrids between Selangor females and Khulna males showed incomplete gametic isolation. Histological observations of the testes of mature males revealed the presence of pycnotic nuclei in the hybrids between Selangor females and Khulna males in addition to normal bundles of spermatozoa. In contrast, no pycnotic nuclei were observed in the Selangor controls. Although meiotic metaphases in the controls were normal, those in hybrids showed several abnormalities, such as the appearance of univalents and an increase in rod-shaped bivalents. Based on our findings from the morphological observations and crossing experiments, we conclude that each of three identified types represents a distinct species. We propose that the large-type is F. cancrivora, the mangrove-type is F. moodiei, and the Sulawesi-type represents an undescribed species.

Another New Bent-toed Gecko, genus Cyrtodactylus Gray 1837 (Squamata: Gekkonidae), from Borneo.

To reveal the diversity of Indonesian bent-toed geckos, we pay attention to Kalimantan (Borneo)an island which has received less attention than other Indonesian islands such as Sumatra, Java, Sulawesi, the Moluccas, and the Lesser Sunda archipelagos. About 30 years after Hikida (1990) described three new Cyrtodactylus from Borneo, four more species were described, namely C. limajalur and C. muluensis in 2019, and C. hantu and C. miriensis in 2021, all by Davis et al. Through examination of the collection at MZB and three addition specimens collected from Tawau, we found several undescribed species, one of which we describe here. This new species is easily differentiated from all other congeners by the combination of the following characters: maximum SVL of at least 65.8 mm; no tubercles on dorsal surface of upper arm; tubercles present in the ventrolateral body folds; 2830 paravertebral tubercles; 1720 longitudinal dorsal tubercle rows; 3946 ventral scale rows at midbody; 1719 subdigital lamellae on fourth toe; precloacal pit with 57 pores in males arranged in a wide -shape but absent in females; no enlarged transverse median subcaudals; paired dark brown semilunar-shaped markings on the upper nape. Further study is needed to reveal its molecular phylogenetic position and biogeographical history.

Genetic divergence and evolutionary relationship in Fejervarya cancrivora from Indonesia and other Asian countries inferred from allozyme and MtDNA sequence analyses.

To elucidate genetic divergence and evolutionary relationship in Fejervarya cancrivora from Indonesia and other Asian countries, allozyme and molecular analyses were carried out using 131 frogs collected from 24 populations in Indonesia, Thailand, Bangladesh, Malaysia, and the Philippines. In the allozymic survey, seventeen enzymatic loci were examined for 92 frogs from eight representative localities. The results showed that F. cancrivora is subdivided into two main groups, the mangrove type and the large- plus Pelabuhan ratu types. The average Nel's genetic distance between the two groups was 0.535. Molecular phylogenetic trees based on nucleotide sequences of the 16S rRNA and Cyt b genes and constructed with the ML, MP, NJ, and BI methods also showed that the individuals of F. cancrivora analyzed comprised two clades, the mangrove type and the large plus Pelabuhan ratu / Sulawesi types, the latter further split into two subclades, the large type and the Pelabuhan ratu / Sulawesi type. The geographical distribution of individuals of the three F. cancrivora types was examined. Ten Individuals from Bangladesh, Thailand, and the Philippines represented the mangrove type; 34 Individuals from Malaysia and Indonesia represented the large type; and 11 individuals from Indonesia represented the Pelabuhan ratu / Sulawesi type. Average sequence divergences among the three types were 5.78-10.22% for the 16S and 12.88-16.38% for Cyt b. Our results suggest that each of the three types can be regarded as a distinct species.

Phylogeny and biogeography of Sumatra´s cloud forest lizards of the genus Dendragama and status of Acanthosaura schneideri.

Lizards of the genus Dendragama are endemic to the highland cloud forests of Sumatra's Barisan Mountain Range in western Indonesia, and recent studies have uncovered widespread diversity within the genus. Here, a suite of morphological characters and mitochondrial DNA are used to compare three geographically isolated populations of D. boulengeri from (1) Mount Kerinci in Jambi province, (2) Mount Marapi of west Sumatra, and (3) the Karo Highlands of north Sumatra. Additional phylogeographic analyses with two recently described sister species, D. australis and D. dioidema were conducted. Five genetically distinct clades of Dendragama, all distributed allopatrically of one another were identified and some are suspected to inhabit small distributions. Morphological and genetic data confirm the Karo Highlands population D. schneideri (previously Acanthosaura schneideri Ahl, 1926) should be revalidated from the synonymy of D. boulengeri. Dendragama schneideri is endemic to montane forests of the Karo Highlands surrounding Lake Toba in Sumatra Utara province. Pairwise genetic distances of 6-11% separate D. schneideri from congeners. Two distinct clades of D. boulengeri from Mount Kerinci and Mount Marapi were identified, which are 5.0% genetically distant from one another. Using morphological characters, we provide the first key for distinguishing between species of Dendragama. Based on biogeographic patterns and levels of genetic variation it is suspected that at least 18 other isolated cloud forest locations may hold new species or divergent populations of Dendragama but lack survey work. Collectively, these comparisons among populations of montane lizards further elucidate the complex biogeographic history of Sumatra's montane forest species and the first phylogeny of the genus Dendragama.

Taxonomic evaluation of two similar bent-toed geckos Squamata: Gekkonidae: Cyrtodactylus Gray, 1827) from East Java, Indonesia.

The bent-toed geckos of the genus Cyrtodactylus are the most speciose land vertebrates of Southeast Asia (about 300 species so far) and new species continue to be recognized at a rapid rate. Within the last decade three new species were described from Java, Indonesia, C. semiadii, C. petani, and C. klakahensis. The latter two are very similar, except for differences in the precloacal depression in adult males. These two species have relatively close type localities, separated from each other by only about 50 km, and with similar habitat type and elevation. Our study aimed to evaluate the taxonomic status of C. klakahensis and C. petani using both morphological and genetic evidence. These two species are genetically similar, with a genetic divergence of only 1.5 to 1.6%. This divergence is well below the level of typically characterizes sister species of Cyrtodactylus (approximately 4% in the mitochondrial ND2 gene), and is more in line with population variation due to geographic distance. Further examination of specimens, from both type localities, showed no diagnostic morphological characters between the two species. Thus, we conclude that C. klakahensis and C. petani are conspecific, and following article 23 of the ICZN, C. klakahensis is herein considered a junior synonym of C. petani.

New species, diversity, systematics, and conservation assessment of the Puppet Toads of Sumatra (Anura: Bufonidae: Sigalegalephrynus).

Using a combination of morphological and molecular data we recognize three new species of Puppet Toad, Sigalegalephrynus Smart, Sarker, Arifin, Harvey, Sidik, Hamidy, Kurniawan Smith, a recently described genus endemic to the highland forests of Sumatra, Indonesia. Phylogenetic analysis of mitochondrial DNA sequences recovered a monophyletic relationship among all Puppet Toads, with two distinct evolutionary clades, a northern and a southern. The northern clade includes Sigalegalephrynus gayoluesensis sp. nov., and S. burnitelongensis sp. nov., and the southern clade includes S. harveyi sp. nov., S. mandailinguensis, and S. minangkabauensis. With the discovery of these three new species, Sigalegalephrynus contains more endemic species than any other genus of toad in Indonesia. We used maximum entropy, implemented in MaxEnt, to identify suitable habitats and occurrence probability of additional undescribed new species from the island. The most important predictors of Sigalegalephrynus distribution were elevation (64.5%) and land cover (7.11%). Based on the probability of presence, it is likely that there are many more species of the genus awaiting discovery in Sumatra. Our analysis, based on IUCN Red List of Threatened Species category and criteria, shows that all of the five species of Sigalegalephrynus are in great risk of extinction and should be placed into the Endangered (EN) category of IUCN Red List.

Genetic divergence and reproductive isolation in the genus Fejervarya (Amphibia: Anura) from Bangladesh inferred from morphological observations, crossing experiments, and molecular analyses.

In the present study, morphological examinations, crossing experiments and molecular analyses were performed to elucidate the degree of genetic divergence and phylogenetic relationships within the genus Fejervarya from Bangladesh and other Asian countries. Morphological characteristics revealed that Fejervarya species from Bangladesh were divided into four distinct groups: large, medium, small, and mangrove types. Crossing experiments indicated the involvement of three reproductive isolating mechanisms: gametic isolation between the large type and mangrove type, hybrid inviability between the large type and two other types, and hybrid sterility between the medium and small types. Experimental results also indicated that these four types of frogs merit the status of individual species of Fejervarya . Molecular analyses based on mtDNA gene sequences showed that the Bangladesh Fejervarya species were largely divided into three groups: the mangrove type, large type, and others, with the last further subdivided into the medium and small types. Comparison with other Asian Fejervarya species revealed that the Bangladesh mangrove type (which resembled F. cancrivora in morphology) was closely related to F. cancrivora from India, Thailand, and the Philippines; the large type belonged to the F. iskandari group and closely resembled F. orissaensis ; the small type was included in the South Asian or Indian group, and was closest to F. syhadrensis from India and Sri Lanka, whereas the medium type was most closely related to F. limnocharis from Myanmar among all described species of this genus.

A new species of Pseudocalotes (Squamata: Agamidae) from the Bukit Barisan Range of Sumatra with an Estimation of its phylogeny.

We describe a new species of Pseudocalotes from montane forests of the central, western coast of Sumatra. The combination of 3 or 4 interoculabials, slightly enlarged and heavily keeled scales on the lower flanks, a white scapular spot, a relatively long fifth toe, bicarinate lamellae at the base of Toe III, absence of a postrictal modified scale, and three rows of paravertebrals directed dorsally and posteriorly distinguishes the new species from its congeners on Sumatra and Java. Among the new characters defined in this study, counts of subdigital lamellae within the "span of Toe V" proved particularly useful for diagnosing species of Pseudocalotes. Phylogenetic analysis of DNA sequences identified a monophyletic group containing the Sumatran and Javan Pseudocalotes. Based on the phylogeny, we define a P. cybelidermus Group containing P. cybelidermus and P. guttalineatus and a P. tympanistriga Group containing P. tympanistriga, P. rhammanotus, and the new species. Combinations of five morphological characters define each of these two clades. As currently defined, Pseudocalotes is polyphyletic; Javan and Sumatran species are more closely related to other draconines such as Dendragama boulengeri than they are to some mainland species.

Redescription Cyrtodactylus lateralis (Werner) (Squamata: Gekkonidae) and Phylogeny of the Prehensile-tailed Cyrtodactylus.

We redescribe Cyrtodactylus lateralis (Werner) on the basis of new specimens. Cyrtodactylus lateralis is a prehensile-tailed species, known from scattered lowland to mid-elevation localities in northern Sumatra. The prehensile-tailed Cyrtodactylus are more speciose and have a wider distribution than previously thought. This group includes a mainland SE Asian clade consisting of C. elok, C. interdigitalis, and C. brevipalmatus and an insular clade containing C. durio, C. lateralis, C. nuaulu, C. serratus, C. spinosus, and C. stresemanni. However, a distinctive color pattern in the Wallacean and Papuan species and uncertainty surrounding the type locality of C. stresemanni raise unresolved questions about the inclusiveness of the insular clade. DNA sequence data supports a close relationship between C. elok and C. interdigitalis, but also reveals that C. lateralis and C. durio are not closely related to these species.

Two new species of Cyrtodactylus (Squamata: Gekkonidae) from the Southern Bukit Barisan Range of Sumatra and an estimation of their phylogeny.

We describe Cyrtodactylus psarops sp. nov. and C. semicinctus sp. nov., two new species of bent-toed geckos from montane forests in the southern Bukit Barisan Range of Sumatra, Indonesia. The new species are closely related to one another and to C. semenanjungensis, a lowland species currently known only from Peninsular Malaysia. Three characters of the new species immediately distinguish them from most congeners in the Sunda Region: they lack transversely enlarged subcaudals, have a precloacal depression, and have a greatly enlarged scale positioned at the apex of a continuous series of femoral and precloacal pore-bearing scales. They differ from one another in cephalic pattern, tuberculation of the brachium, and in numbers of cloacal tubercles, dorsal bands, and ventrals in a transverse row. The greatly enlarged scale at the apex of the precloacal pores appears to be a rare apomorphy of these two species and C. agamensis.

Three new species of Pseudocalotes (Squamata: Agamidae) from southern Sumatra, Indonesia.

We describe three new species of Pseudocalotes from the Bukit Barisan Range of southern Sumatra, Indonesia. Pseudocalotes cybelidermus, P. guttalineatus, and P. rhammanotus differ from most congeners in having serrate dorsal crests that extend to the base of the tail and a dorsolateral series of enlarged heavily keeled scales. In these new species, subdigital lamellae of Toe III have prominent preaxial keels and lack or have greatly reduced postaxial keels. In contrast, P. rhammanotus resembles P. tympanistriga by having bicarinate subdigital lamellae at the base of Toe III. Like most congeners, these new species appear to be restricted to humid forests above 1000 m. We report several new morphological characters for Pseudocalotes and discuss their diagnostic value. Future systematic studies of this genus should assess presence/absence of interparietals, four different kinds of modified scales on the neck, a dorsolateral series of heavily keeled scales, and unicarinate lamellae under the distal phalanges of most fingers and toes. Our comparisons among congeners demonstrate the diagnostic value of width of the gap between the nuchal and dorsal crests and frequency data for contact between the nasal and supralabials and between the postmentals and infralabials. Finally, we discuss variation in morphology of subdigital lamellae at the base of Toe III and describe new conditions intermediate between the serrate fringe of most Indochinese species and the bicarinate lamellae of the P. tympanistriga.