RESUMO
A tiny new species of narrow-mouthed frog of the genus Microhyla is described from the island of Belitung and southeastern Sumatra, Indonesia. The most distinctive feature of the new frog is its diminutive adult size, snout-vent length ranging only from 12.3 to 15.8 mm in adult males. Phylogenetic analyses based a fragment of the mitochondrial 16S rRNA gene, along with detailed morphological and acoustic comparison differentiate the new taxon from all known congeners. The new species, formally described as Microhyla sriwijaya sp. nov., is a member of the M. achatina species group and the sister taxon to M. orientalis. It is diagnosable from other congeners by a combination of characters: (1) smaller male snout-vent size 16 mm; (2) snout obtusely rounded in dorsal view; (3) absence of mid-dorsal line and skin fold; (4) first finger reduced (finger I length less than half of finger II length); (5) dorsum with a prominent dark median mark extending posteriorly, narrow anteriorly near the level of the shoulder and expanding dorsolaterally up to the vent; margins of the dorsal marking concave with broad reddish-brown or orange colouration on either side; (6) foot webbing rudimentary, reaching just up to the first subarticular tubercle on all toes; (7) dorsal skin with prominent tubercles, especially in life; (8) tibiotarsal articulation of adpressed limb reaching beyond the snout tip; and (9) males produce a single type of call with pulsatile temporal structure, calls of relatively short duration ranging between 31.862.8 s, with two to three pulses delivered at a rate ranging between 32.236.0 pulses per second, and the mean overall dominant frequency of 4.3 kHz. The uncorrected pairwise genetic distances between Microhyla sriwijaya sp. nov. and all other known congeners are > 3.8% for the studied 16S gene fragment. The new species was discovered from wayside rural areas with oil palm plantations at four localities in the small island of Belitung (type locality), and from coffee plantation and secondary forest at Lampung in southeastern Sumatra. It is not known from any protected area and appears to be threatened due to tin mining activity, intensive logging, oil palm, and other commonly practiced agriculture activities.
Assuntos
Anuros , Florestas , Animais , Anuros/genética , Indonésia , Masculino , Filogenia , RNA Ribossômico 16S/genéticaRESUMO
Micryletta inornata (Boulenger 1890), the type species of the genus Micryletta, was originally described from the island of Sumatra in Indonesia. Subsequently, this species has been widely reported from Sundaland (Sumatra and Malay Peninsula), Indo-China, Northeast India and South Andaman, up to southern China and Taiwan. However, since the original description there has been no further report of this species from the type locality or the island. During a herpetofaunal survey in Sumatra, several specimens that are morphologically concordant with the original description and the syntypes of M. inornata were found, and thus the species was rediscovered after 125 years. Here, we provide a redescription of the species based on the freshly collected specimens, along with a detailed morphological and molecular comparison with known congeners. Further, using molecular data from the mitochondrial 16S rRNA gene, our study recovered the Sumatran M. inornata as a phylogenetically distinct lineage from all other populations previously referred to this species. This confirms that all known Micryletta 'inornata' populations from regions outside Sumatra constitute several other lineages representing either new species or previously available names currently considered as synonyms, consequently requiring taxonomic validation in the future.
