Sunday, January 31, 2016

[Herpetology • 2016] Systematic Revision of the Taiwanese Genus Kurixalus members (Anura, Rhacophoridae) with A Description of Two New Endemic Species; Kurixalus berylliniris & K. wangi

Figure 3. Four Kurixalus species of Taiwan.
Kurixalus berylliniris sp. n. (holotype, adult, dark morph) B K. wangi sp. n. (holotype) C K. berylliniris sp. n. (sub-adult) D K. berylliniris sp. n. (adult, light morph) E K. eiffingeri F K. idiootocus.

Two new species of rhacophorid tree frog were identified in Taiwan. In both new taxa, derived reproductive characteristics of laying eggs in tree holes and oophagous tadpoles are shared with Kurixalus eiffingeri, but they are divergent from each other in molecular genetics, mating calls, and tadpole and adult morphology. The morphological characteristics and the molecular phylogenetic evidence support the hypothesis that the two new speciesKurixalus berylliniris sp. n. and Kurixalus wangi sp. n., are both monophyletic lineages.

Keywords: Kurixalus berylliniris sp. n., Kurixalus wangi sp. n., oophagous tadpoles

Figure 1. Sampling localities of this study.
Localities 1 through 22 are around Taiwan island, locality 23 from Iriomote isle, locality 24 from Ishigaki isle. The two isles belong to the southern end of Ryukyu archipelago. Color refers to the geographical distribution of the three Kurixalus species. Red: Kurixalus eiffingeri; Green: K. berylliniris sp. n. (Taxon 1); B: K. wangi sp. n. (Taxon 2). Loc. 20: Ligia, type locality of K. berylliniris sp. n.; Loc. 21: Shouka, type locality of K. wangi sp. n.

Figure 10. Phylogenetic relationship of all Kurixalus species from Taiwan. A phylogram showing the phylogenetic relationships of the four Kurixalus species, obtained by a maximum likelihood search based on 1207 nucleotides from mtDNA CO1 and 16S rRNA genes. Feihyla palpebralis and Rhacophorus moltrechti were used as outgroups. The three values on each branch are maximum likelihood (ML), maximum parsimony (MP), and neighbor-joining (NJ) analyses with bootstrapping support based on 2000 replicates. Bootstrapping values below 50% are not shown. (JP: Ryukyu Islands of Japan; N. TW: northern Taiwan; C. TW: central Taiwan).

Kurixalus berylliniris sp. n.

Type locality: Ligia timber trail, 1250 meters above sea level, Taitung County, Taiwan, Republic of China (Fig. 1, Loc. 20, 22°49'26.79"N, 121°00'35.45"E).

Diagnosis: A moderate-sized Kurixalus. Females average about 41 mm snout-vent length (range: 27.6–46.3 mm); males average about 35 mm (range: 29.0–42.3 mm). Iris emerald to light green. Two dark brown spots on eyelids, separated from each other and from X-shaped blotch on dorsum. Subarticular tubercles on foot rounded and flat. Belly and throat white or faintly-speckled. Prepollex in males squarish, compressed and expanded. About half-webbed between two outer toes. Anterior margin of tadpole dorsal fin extending to body. Tadpole heavily dark brown to black pigmented in gular region and on tail muscle. Upper lip of tadpole with deep transverse furrow, and prominent ridge extending from upper lip to anterior margin of nostril (key of tadpole, 3).

Etymology: The epithet berylliniris is a compound word formed from beryllin (L.), green-colored, and from iris (L.), iris of the eye, and is treated as a noun in nominative singular in opposition to the generic name.

Distribution and ecological notes: Kurixalus berylliniris sp. n. occurs in eastern Taiwan (at 225 to 1250 meters above sea level). The highest recorded elevation was on the eastern slope of the Central Mountain Range (Taitung County, 1250 meters above sea level), and the lowest recorded elevation was on the western slope of the Coastal Range (Hwalien County, 225 meters above sea level). Specimens were collected near the canopy level in moist broad-leaf forests in Taitung and on forest edges in Hwalien. The northern border of the specimen’s distribution was near the Guangfu township of the central Hualien County (Fig. 1, Green stain).

Kurixalus wangi sp. n.

Type locality: Shouka timber trail, 400 meters above sea level, Pingtung County, Taiwan, Republic of China (Fig. 1, Loc. 21, 22°13'15.58"N, 120°49'21.92"E).

Diagnosis: A small to moderate-sized Kurixalus. Females snout-vent length averaging about 34 mm (range: 30.8–37.1 mm); males averaging 30 mm (range: 28.6–31.6 mm). Iris golden-yellow. Two anterior horns of the X-shaped marking on back extending to eyelid. Webbing extensive on toes, extending to the toe disc on the inner margin of toe V. Belly and throat whitish. Anterior margin of tadpole dorsal fin extending to posterior body. Tadpole with almost no pigment on region of tail muscle. Upper lip of tadpole with shallow transverse furrow.

Etymology: The epithet is named and dedicated to Mr. Ching-Shong Wang for his pioneering work and contributions to the herpetology of Taiwan (Wang 1962). Mr. Wang discovered two rhacophorid frogs (Rhacophorus taipeianus and K. idiootocus) (Liang and Wang 1963, Kuramoto and Wang 1987) in Taiwan and suggested, in the early 1980s, that some Kurixalus specimens collected near the type locality of this new species might be different from K. eiffingeri (personal communication). The name is used in the genitive case.

Distribution and ecological notes: Kurixalus wangi sp. n. is distributed in the southern part of Pingtung County in southern Taiwan below 500 meters above sea level (Fig. 1, Blue dots). All specimens were collected in the shrubs of secondary forests or lowland broad-leaved forests at low altitudes.

Figure 4. Nesting sites of three tree-hole breeding Kurixalus species (a nest is made by the animal).
A eggs of Kurixalus berylliniris sp. n. B eggs of K. wangi sp. n.; note that the parents were present with eggs C eggs of K. eiffingeri.

Phylogenetic relationships

As demonstrated by the high bootstrap support, the robustness of the phylogenetic relationship of the three rhacophorid genera is strong. Based on this robust phylogenetic tree, we found that the among-genera genetic distances were greater than the within-genus genetic distance (Fig. 10). Using the partial sequence of mtDNA CO1 gene as a molecular marker (Table S2), the genetic distances of the all pair-wise comparisons of the four Kurixalus species were all larger than 10% (Table S3). The phylogenetic trees constructed by Bayesian inference, NJ analysis, and MP methods showed the same topology (Fig. 10). The topology of branches was sufficiently supported by the posterior probabilities, bootstrap values, and branch lengths. The four Kurixalus species of Taiwan formed a well-structured monophyletic group with distinguishable branch length. Samples of K. eiffingeri collected from Iriomote Island, northern Taiwan, and central Taiwan were embedded in the same lineage and formed a monophyletic group (Fig. 11 below). Individuals from southern (Kurixalus wangi sp. n.) and eastern Taiwan (K. berylliniris sp. n.) were sister taxa of K. eiffingeri. Kurixalus idiootocus was phylogenetically distinct from the three Kurixalus species (Figs 10 and 11 below).

Figure 11. Geographic distribution and genetic structures of Kurixalus eiffingeri and the two newly discovered cryptic species from Taiwan and its two adjacent islands. Red: K. eiffingeri; Green: K. berylliniris sp. n.; B: K. wangi sp. n. Bold lines mark the boundaries of each species’ distribution, dotted lines discriminate different genetic groups intra species. Below: a consensus ML tree to show the variation between haplotypes.

Shu-Ping Wu, Chuan-Chin Huang, Chi-Li Tsai, Te-En Lin, Jhih-Jia Jhang and Sheng-Hai Wu. 2016. Systematic Revision of the Taiwanese Genus Kurixalus members with A Description of Two New Endemic Species (Anura, Rhacophoridae).
ZooKeys. 557: 121-153. DOI:  10.3897/zookeys.557.6131

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