|Rana neba Ryuzaki, Hasegawa & Kuramoto, 2014|
Figure 2. Holotype of Rana neba sp. nov. (LABHU F2553): Dorsal view (A) and ventral view (B). SVL 45.1 mm.
The Japanese brown frog from Nagano Prefecture, previously reported as Rana tagoi with 2 n = 28 chromosomes, is described as a new species. The new species differs only slightly in morphology from topotypic R. tagoi tagoi. It has a greater snout-nostril length, smaller fourth finger length, smaller fourth and fifth toe lengths (all relative to snout-vent length) and a narrower web, but is practically indistinguishable from a neighboring R. tagoi tagoi population. However, distinct acoustic differences in their advertisement calls clearly separate the two taxa, and may serve as an effective pre-mating isolation mechanism. Karyotypic difference between the new species and R. tagoi tagoi results in nearly complete hybrid sterility. Because the new species is nested within a clade comprising neighboring R. tagoi populations, the new species must have originated rather recently by chromosome reconstruction, and subsequent acoustic divergence would have facilitated conspecific mating. This species is an example of an anuran sibling species that is unrelated to molecular phylogeny.
Rana neba sp. nov.
Synonymy. Rana tagoi (2 n = 28): Ryuzaki et al. (2006)
Masashi Ryuzaki, Yoshinori Hasegawa and Mitsuru Kuramoto. 2014. A New Brown Frog of the Genus Rana from Japan (Anura: Ranidae) revealed by Cytological and Bioacoustic Studies. Alytes. 31(3-4); 49-58.