More Like this

1. Unexpectedly high levels of lineage diversity in Sundaland Puddle Frogs (Dicroglossidae: Occidozyga Kuhl and Van Hasselt, 1822).

   Flury, J. ( January 2021 , Molecular phylogenetics and evolution)

   null (Ed.)

   One of the most urgent contemporary tasks for taxonomists and evolutionary biologists is to estimate the number of species on earth. Recording alpha diversity is crucial for protecting biodiversity, especially in areas of elevated species richness, which coincide geographically with increased anthropogenic environmental pressures - the world’s so-called biodiversity hotspots. Although the distribution of Puddle frogs of the genus Occidozyga in South and Southeast Asia includes five biodiversity hotspots, the available data on phylogeny, species diversity, and biogeography are surprisingly patchy. Samples analyzed in this study were collected throughout Southeast Asia, with a primary focus on Sundaland and the Philippines. A mitochondrial gene region comprising ~ 2000 bp of 12S and 16S rRNA with intervening tRNA Valine and three nuclear loci (BDNF, NTF3, POMC) were analyzed to obtain a robust, time-calibrated phylogenetic hypothesis. We found a surprisingly high level of genetic diversity within Occidozyga, based on uncorrected p-distance values corroborated by species delimitation analyses. This extensive genetic diversity revealed 29 evolutionary lineages, defined by the > 5% uncorrected p-distance criterion for the 16S rRNA gene, suggesting that species diversity in this clade of phenotypically homogeneous forms probably has been underestimated. The comparison with results of other anuran groups leads to the assumption that anuran species diversity could still be substantially underestimated in Southeast Asia in general. Many genetically divergent lineages of frogs are phenotypically similar, indicating a tendency towards extensive morphological conservatism. We present a biogeographic reconstruction of the colonization of Sundaland and nearby islands which, together with our temporal framework, suggests that lineage diversification centered on the landmasses of the northern Sunda Shelf. This remarkably genetically structured group of amphibians could represent an exceptional case for future studies of geographical structure and diversification in a widespread anuran clade spanning some of the most pronounced geographical barriers on the planet (e.g., Wallace’s Line). Studies considering gene flow, morphology, ecological and bioacoustic data are needed to answer these questions and to test whether observed diversity of Puddle frog lineages warrants taxonomic recognition. 

   more » « less
2. A new, morphologically cryptic species of fanged frog, genus Limnonectes (Amphibia: Anura: Dicroglossidae), from Mindoro Island, central Philippines.

   Mark W. Herr, Johana Goyes ( January 2021 , Copeia)

   null (Ed.)

   We describe a new species of fanged frog (genus Limnonectes) from Mindoro and Semirara Islands, of the Mindoro Pleistocene Aggregate Island Complex, of the central Philippines. Although morphologically indistinguishable from its closest relative, Limnonectes acanthi, of the Palawan faunal region, the two species can be readily diagnosed on the basis of spectral (dominant frequency) and temporal (pulse number and structure) properties of their advertisement calls, and their allopatric insular geographic ranges on permanently separate geological platforms which have not been connected by dry land in the recent geological past—all of which we interpret as congruent and independent lines of evidence supporting our recognition of two independently evolving evolutionary lineages (species). Ribosomal RNA mitochondrial gene sequences were used to provide genetic identification of specimens and estimate phylogenetic relationships; genetic divergences between Palawan and Mindoro faunal regions exceed those estimated among other, uncontroversial, phenotypically distinct Philippine species with equivalent levels of allopatry and biogeographic isolation. The recognition of the new species further emphasizes the degree to which even well-studied Philippine landmasses still harbor unrecognized biodiversity, and suggests that other widespread Philippine fanged frogs should be scrutinized for non-traditional diagnostic character differences (mate-recognition signal divergence, ecological differences, larval characteristics, life-history trait variation), especially when their geographic ranges span the archipelago’s permanent, deep-water trenches, which define its well-characterized Pleistocene Aggregate Island Complexes 

   more » « less
3. On the second (or, rather, the first) specimen of the recently described Calliophis salitan (Squamata: Elapidae), with the first report of the species from Mindanao Island, southern Philippines

   Rafe M. Brown, Marta Calvo-Revuelta ( January 2021 , Herpetology notes)

   null (Ed.)

   Abstract. We report on the second known specimen of the recently described banded Asian coralsnake, Calliophis salitan, identified among the Museo Nacional de Ciencias Naturales collections of Dr. Hipólito Fernández, made in 1886. The specimen was collected on Mindanao Island in the southern Philippines as part of the “Comisión Central de Manila,” the Spanish Crown’s effort to catalogue and showcase Philippine biodiversity for the Madrid public. We assign this important specimen to C. salitan (formerly known from a single specimen collected on Dinagat Island) based on its highly distinctive external phenotypic characteristics (scalation, body size, and inferred colour pattern). The discovery of C. salitan on Mindanao significantly extends the known geographic range of this species and partially fills an intermediate distributional hiatus – a large geographic gap in the distribution of large-bodied, long-glanded coralsnakes. This report partially resolves a biogeographic enigma surrounding the question of how a distinctive evolutionary lineage of elapid snakes – more closely related to the Calliophis bivirgatus group from Borneo and other landmasses of Sundaland than to any other Philippine elapids – could have colonized only a small island (Dinagat) in the geographic interior of the archipelago. The answer appears, most likely, that this dispersal occurred over land, via the large intervening island of Mindanao. Although the exact site of collection is unknown, consideration of the collector’s itinerary suggests that it originated most likely in the vicinity of Davao City, southeastern Mindanao. Its discovery confirms that C. salitan occurs on Mindanao (or, at least, did occur on this island as recently as 133 years ago), and that locating additional populations via targeted surveys is an urgent priority for conservation of this remarkable Philippine endemic snake lineage. 

   more » « less
4. Where Are the Proto‐South China Sea Slabs? SE Asian Plate Tectonics and Mantle Flow History From Global Mantle Convection Modeling

   https://doi.org/10.1029/2020JB019758  

   Lin, Yi‐An ; Colli, Lorenzo ; Wu, Jonny ; Schuberth, Bernhard S. A. ( December 2020 , Journal of Geophysical Research: Solid Earth)

   The plate tectonic history of the hypothesized “proto‐South China Sea” (PSCS) ocean basin and surrounding SE Asia since Cenozoic times is controversial. We implement four diverse proto‐South China Sea plate reconstructions into global geodynamic models to constrain PSCS plate tectonics and possible slab locations. Our plate reconstructions consider the following: southward versus double‐sided PSCS subduction models; earlier (Eocene) or later (late Oligocene) initiation of Borneo counterclockwise rotations; and larger or smaller reconstructed Philippine Sea plate sizes. We compare our modeling results against tomographic images by accounting for mineralogical effects and the finite resolution of seismic tomography. All geodynamic models reproduce the tomographically imaged Sunda slabs beneath Peninsular Malaysia, Sumatra, and Java. Southward PSCS subduction produces slabs beneath present Palawan, northern Borneo, and offshore Palawan. Double‐sided PSCS subduction combined with earlier Borneo rotations uniquely reproduces subhorizontal slabs under the southern South China Sea (SCS) at ~400 to 700 km depths; these models best fit seismic tomography. A smaller Philippine Sea (PS) plate with a ~1,000‐km‐long restored Ryukyu slab was superior to a very large PS plate. Considered together, our four end‐member plate reconstructions predict that the PSCS slabs are now at <900 km depths under present‐day Borneo, the SCS, the Sulu and Celebes seas, and the southern Philippines. Regardless of plate reconstruction, we predict (1) mid‐Cenozoic passive return‐flow upwellings under Indochina; and (2) late Cenozoic downwellings under the SCS that do not support a deep‐origin “Hainan plume.” Modeled Sundaland dynamic topography strongly depends on the imposed plate reconstructions, varying by almost 1 km.

    

   more » « less
5. A new forest frog of the genus Platymantis (Amphibia: Anura: Ceratobatrachidae: subgenus Tirahanulap) from Leyte and Samar islands, eastern Philippines

   https://doi.org/10.11646/zootaxa.4830.3.6  

   DIESMOS, ARVIN C. ; SCHEFFERS, BRETT R. ; MALLARI, NEIL ALDRIN ; SILER, CAMERON D. ; BROWN, RAFE M. ( August 2020 , Zootaxa)

   null (Ed.)

   We describe a new species of frog of the genus Platymantis Günther (subgenus Tirahanulap), from the east-central regions of the Philippines. It belongs to the the previously-defined P. hazelae Group) based on morphological and bioacoustic datasets. The new species is phenotypically and ecologically most similar to members of Tirahanulap, an assemblage of small-bodied arboreal frogs inhabiting montane forests of the central and northern islands of the Philippine archipelago. The new species represents the first taxon in the Cloud Frog species known from the biogeographically unique Mindanao Pleistocene Aggregate Island Complex. Particularly susceptible to local extirpation following deforestation, all known species of Tirahanulap are important indicator species for environmental and conservation assessments, making this new species not only an exceptional addition to Philippine biodiversity but also an important symbol for conservation initiatives in the region. 

   more » « less