Revision of the horseface loaches (Cobitidae, Acantopsis), with descriptions of three new species from Southeast Asia.

Acantopsis (Cobitidae) is revised based on analysis of morphological and molecular data. Four of the six available names, A. dialuzona, A. spectabilis, A. octoactinotos, and A. thiemmedhi, are valid, and three new species, A. rungthipae, A. dinema, and A. ioa, are described. All species are described morphologically, distributions are mapped, and relationships are discussed for those for which molecular data (CO1, RAG1) are available. Labial barbels, color pattern, and meristic counts are the most diagnostic features. Although the long snout of Acantopsis is perhaps the most emblematic attribute of the genus, its relative length increases with growth, reducing its taxonomic value. Species can be difficult to identify on the basis of color pattern alone, as habitat and preservation methods appear to strongly influence the color pattern. Despite interspecific overlap of some highly variable traits, each species has a unique set of morphological characteristics that remain observable even when the color pattern is obscured, and some species are restricted to single drainages, greatly simplifying identification. The phylogenetic analyses revealed high molecular divergence between even the most morphologically similar species, with mean uncorrected CO1 p-distances between species ranging from 12.1-15.4%. Species of Acantopsis exhibit significant genetic structuring consistent with recognized freshwater ecoregions. Acanthopsis lachnostoma Rutter 1897, from Swatow, China, is not assignable to Acantopsis.

A review of the glyptosternine catfish genus Exostoma Blyth 1860 from Thailand, with descriptions of two new species (Teleostei: Siluriformes).

We review members of the sisorid catfish genus Exostoma known from Thailand. Three species are recognized, of which two from the headwaters of the Chao Phraya River drainage in northwestern Thailand, are described here as new: E. effrenum and E. peregrinator. In addition to the two new species, E. berdmorei (which is here redescribed) is also known from the Salween River drainage in western Thailand. The three species can be distinguished from each other and other congeners by the morphologies of the adipose and caudal fins, as well as morphometric data for the eye diameter, head width, dorsal-to-adipose distance, body depth at anus, caudal-peduncle length, caudal-peduncle depth, and numbers of branched pectoral-fin rays and preanal vertebrae. 

Tetraodon palustris, a new freshwater pufferfish (Tetraodontiformes: Tetraodontidae) from the Mekong Basin of Thailand.

Tetraodon palustris, new species, is described from the Mekong basin of Thailand. Tetraodon palustris differs from T cochinchinensis and T. fangi in having no ocellus on the flank and spinules dorsally from the interorbital region to the end of the dorsal-fin base. T. etraodon cochinchinensis is distinguished from T. fangi by having a longer snout (43.5-49.2% HL in T. cochinchinensis vs. 37.9-41.1% HL in T. fangi) and is covered with spinules dorsally from the front of the nasal organs to the end of the dorsal-fin base (vs. from the front of the eyes to the end of the dorsal-fin base in T. fangi).

Thampramon tonvuthi, a new genus and new species of cavernicolous crab (Crustacea: Decapoda: Brachyura: Potamidae) from Thailand.

A new genus and species of potamid cavernicolous crab, Thampramon tonvuthi sp. nov., is described from Thailand. While superficially similar to Tiwaripotamon Bott, 1970, Phaibulamon Ng, 1992, and Nemoron Ng, 1996, the new genus possesses a unique combination of morphological characters including a distinctive carapace form, possession of a relatively long third maxilliped exopod, long ambulatory legs and a unique male first gonopod.

Systematics of the subfamily Danioninae (Teleostei: Cypriniformes: Cyprinidae).

The members of the cyprinid subfamily Danioninae form a diverse and scientifically important group of fishes, which includes the zebrafish, Danio rerio. The diversity of this assemblage has attracted much scientific interest but its monophyly and the relationships among its members are poorly understood. The phylogenetic relationships of the Danioninae are examined herein using sequence data from mitochondrial cytochrome b, mitochondrial cytochrome c oxidase I, nuclear opsin, and nuclear recombination activating gene 1. A combined data matrix of 4117 bp for 270 taxa was compiled and analyzed. The resulting topology supports some conclusions drawn by recent studies on the group and certain portions of the traditional classification, but our results also contradict key aspects of the traditional classification. The subfamily Danioninae is not monophyletic, with putative members scattered throughout Cyprinidae. Therefore, we restrict Danioninae to the monophyletic group that includes the following genera: Amblypharyngodon, Barilius, Cabdio, Chela, Chelaethiops, Danio, Danionella, Devario (including Inlecypris), Esomus, Horadandia, Laubuca, Leptocypris, Luciosoma, Malayochela, Microdevario, Microrasbora, Nematabramis, Neobola, Opsaridium, Opsarius, Paedocypris, Pectenocypris, Raiamas, Rasbora (including Boraras and Trigonostigma), Rasboroides, Salmostoma, Securicula, and Sundadanio. This Danioninae sensu stricto is divided into three major lineages, the tribes Chedrini, Danionini, and Rasborini, where Chedrini is sister to a Danionini-Rasborini clade. Each of these tribes is monophyletic, following the restriction of Danioninae. The tribe Chedrini includes a clade of exclusively African species and contains several genera of uncertain monophyly (Opsarius, Raiamas, Salmostoma). Within the tribe Rasborini, the species-rich genus Rasbora is rendered non-monophyletic by the placement of two monophyletic genera, Boraras and Trigonostigma, hence we synonymize those two genera with Rasbora. In the tribe Danionini, the miniature genus Danionella is recovered as the sister group of Danio, with D. nigrofasciatus sister to D. rerio.

A new orang-utan relative from the Late Miocene of Thailand.

The fossil record of the living great apes is poor. New fossils from undocumented areas, particularly the equatorial forested habitats of extant hominoids, are therefore crucial for understanding their origins and evolution. Two main competing hypotheses have been proposed for orang-utan origins: dental similarities support an origin from Lufengpithecus, a South Chinese and Thai Middle Miocene hominoid; facial and palatal similarities support an origin from Sivapithecus, a Miocene hominoid from the Siwaliks of Indo-Pakistan. However, materials other than teeth and faces do not support these hypotheses. Here we describe the lower jaw of a new hominoid from the Late Miocene of Thailand, Khoratpithecus piriyai gen. et sp. nov., which shares unique derived characters with orang-utans and supports a hypothesis of closer relationships with orang-utans than other known Miocene hominoids. It can therefore be considered as the closest known relative of orang-utans. Ancestors of this great ape were therefore evolving in Thailand under tropical conditions similar to those of today, in contrast with Southern China and Pakistan, where temperate or more seasonal climates appeared during the Late Miocene.