Oxyeleotris colasi (Teleostei : Eleotridae), a new blind cave fish from Lengguru in West Papua, Indonesia

Oxyeleotris colasi is the first hypogean fish recorded from West Papua. The habitat consists of a freshwater pool in the cave of Jabuenggara located in the heart of Seraran anticline in the limestone karst of Lengguru. The new species is most closely related to the blind cave fish O. caeca described by Allen (1996) from eastern New Guinea. The two troglomorphic species are hypothesised to be related to O. fimbriata, an epigean freshwater gudgeon that ranges widely in New Guinea and northern Australia (Allen, 1996). Oxyeleotris colasi differs from its congeners by the absence of eyes, its skin and fins being totally depigmented, the presence of a well developed sensory papillae system partly consisting of low raised fleshy ridges on each side of the head, a reduced number of cephalic sensory pores, a reduced number of scales on head and body, a long head with a short snout length, a narrow mouth width and a long upper jaw length, body shape with a shallow anterior body depth and narrow body width, a long and deep caudal peduncle, long predorsal and prepectoral lengths, and a long pectoral fin

Mitochondrial genomic divergence in coelacanths (Latimeria) : slow rate of evolution or recent speciation ?

Dating the divergence between the two known living species of coelacanths has remained a difficult issue because of the very ancient origin of this lineage of fish, which is more closely related to tetrapods than to other fishes. We sequenced the complete mitochondrial genome of a recently captured individual of the Indonesian coelacanth in order to solve this issue. Using an approach based on loglinear models, we studied the molecular divergence between the two species of coelacanths and three other pairs of species, one that has diverged recently (Pan) and two that have diverged more distantly in the past. The loglinear models showed that the divergence between the two species of coelacanths is not significantly different from the two species of Pan. A detailed gene by gene analysis of the patterns of nucleotide and amino acid substitutions between these two pairs of species further supports the similarity of these divergences. On the other hand, a molecular dating analysis suggested a much older origin of the two coelacanth species (between 20 and 30 million years ago). We discuss the potential reasons for this discrepancy. The analysis of new individuals of the Indonesian coelacanth will certainly help to solve this issue