Sunday, April 15, 2018

[Herpetology • 2018] Leptolalax purpurus & L. yingjiangensis • Two New Sympatric Species of the Genus Leptolalax (Anura: Megophryidae) from western Yunnan of China


Comparisons of dorsal and ventral color patterns in life of three sympatric Leptolalax species in Tongbiguan Town, Yingjiang County of Yunnan Province: (A–B) paratype SYS a006532 of Leptolalax purpurus sp. nov.(C–D) paratype SYS a006535 of Leptolalax yingjiangensis sp. nov.(E–F) Leptolalax ventripuntactus, KFBG 14512. 

Yang​, Zeng & Wang, 2018
   DOI:  10.7717/peerj.4586 

Abstract

The Asian leaf litter toads of the genus Leptolalax represent a highly diverse species group and currently contain 53 recognized species. During herpetological surveys in Yingjiang County, western Yunnan of China, we collected series of Leptolalax specimens from an isolated small fragment of montane evergreen forest. Subsequent study based on acoustic, morphological and molecular data reveals that there were three different species among the specimens sampled: while one of them belongs to Leptolalax ventripunctataus, the other two species represent unknown taxa and are described herein: Leptolalax purpurus sp. nov. and Leptolalax yingjiangensis sp. nov. The two new species can be distinguished from other congeners by the molecular divergences, acoustic data, and by a combination of morphological characters including: body size, dorsal and ventral patterns, dorsal skin texture, sizes of pectoral and femoral glands, degree of webbing and fringing on the toes and fingers, dorsum coloration and iris coloration in life. Our results further reveal that species diversity of the genus Leptolalax still remains highly underestimated and warrants further attention.



Leptolalax purpurus sp. nov.

Etymology. The species epithet, “purpurus”, is given as a noun in apposition and means “purple color”, in reference to the purplish dorsum coloration in life of the new species. For the common name, we suggest “Purplish-brown Leaf Litter Toad” (English) and “紫棕掌突蟾” (Chinese).

Figure 2: Holotype of Leptolalax purpurus sp. nov. (SYS a006531) in life: (A) dorsolateral view; (B) iris coloration; (C) ventral view; (D) plantar view of the left foot; (D) volar view of the left hand. Photos by JH Yang.

Diagnosis. Leptolalax purpurus sp. nov. can be distinguished from its congeners by a combination of the following characters: (1) small size (SVL 25.0–27.5 mm in males); (2) dorsal skin shagreened and scattered with fine, round reddish tubercles; (3) tympanum distinctly discernible, almost entirely black; (4) webbing and lateral fringes on fingers absent; (5) toes with rudimentary webbing and wide lateral fringes; (6) pectoral gland larger than tips of fingers and femoral gland; (7) ventrolateral glands distinct; (8) dorsum coloration purplish brown in life; (9) flanks with distinct irregular black spots; (10) black marking/spots on dorsum and flanks mottled with distinct yellow pigmentation in life; (11) ventral side dull white with indistinct grey dusting; (12) relatively short hindlimbs (males TIB/SVL ratio 0.43–0.45 in purpurus; males HLL/SVL ratio 1.41–1.48); (13) iris bicolored, upper half orange yellow, lower half sliver white; (14) a call consisting of a single note and a dominant frequency of 4.3–4.5 kHz (at 15 °C).

Distribution and natural history. Leptolalax purpurus sp. nov. is currently only known from its type locality in Tongbiguan Town, Yingjiang County of Yunnan Province, China. The male holotype SYS a006531 was found perching under leaf litter nearby a small clear-water rocky stream (ca. 1–2 m in width and ca. 5–20 cm in depth), flowing through a montane evergreen broadleaf forest, on 7 December 2016, and no calls were detected during the survey. Only a single male individual (paratype SYS a006530) was found calling and perching on top of a small rock along the stream on 20 April 2017, and no more calls and individuals were detected during the survey. No male calls and individuals of the new species were detected during other two night surveys on 5 May 2016 and 10 June 2017.


Figure 3: Comparisons of dorsal and ventral color patterns in life of three sympatric Leptolalax species in Tongbiguan Town, Yingjiang County of Yunnan Province: 
(A–B) paratype SYS a006532 of Leptolalax purpurus sp. nov.;
(C–D) paratype SYS a006535 of Leptolalax yingjiangensis sp. nov.;
(E–F) Leptolalax ventripuntactus, KFBG 14512.
Photos by JH Yang.


 

Leptolalax yingjiangensis sp. nov.

Etymology. The specific name “yingjiangensis”, is in reference to the type locality of the new species, Yingjiang County of Yunnan Province, China. For the common name, we suggest “Yingjiang Leaf Litter Toad” (English) and “盈江掌突蟾” (Chinese).

Figure 7: Holotype of Leptolalax yingjiangensis sp. nov. (SYS a006532) in life: (A) dorsolateral view; (B) iris coloration; (C) ventral view; (D) plantar view of the left foot; (D) volar view of the left hand. Photos by JH Yang.

Diagnosis. Leptolalax yingjiangensis sp. nov. can be distinguished from its congeners by a combination of the following characters: (1) small size (SVL 25.7–27.6 mm in males); (2) dorsal skin shagreened and scattered with fine, round brown tubercles; (3) tympanum distinctly discernible, upper half black; (4) fingers webbing absent, and narrow to moderate dermal fringes present on 2nd to 4th fingers; (5) toes with rudimentary webbing and wide lateral fringes; (6) pectoral gland smaller than femoral gland; (7) ventrolateral glands distinct; (8) distinct tiny white flecks present on edges of dark brown markings/blotches on dorsum; (9) flanks with distinct irregular black spots; (10) ventral surface of body creamy white and scattered with distinct small dark brown flecks on chest and lateral sides of belly; (11) iris bicolored, upper half orange yellow, lower half sliver white; (12) a call consisting of a single note and a dominant frequency of 5.7–5.9 kHz (at 19 °C).



Distribution and natural history. Leptolalax yingjiangensis sp. nov. is currently only known from its type locality in Yingjiang County of Yunnan Province, China. The male holotype was found calling and perching under leaf litter nearby a small clear-water rocky stream (exactly the same stream as types of Leptolalax purpurus), on 5 May 2016, and very few male calls were detected during the survey. While during the survey on 10 June 2017, calling males of the new species were ubiquitous along the stream and riparian forest, and four calling males were collected. No male calls and individuals of the new species were detected during other two night surveys on 8 December 2016 and 20 April 2017.


Jian-Huan Yang​, Zhao-Chi Zeng and Ying-Yong Wang. 2018. Description of Two New Sympatric Species of the Genus Leptolalax (Anura: Megophryidae) from western Yunnan of China. PeerJ. 6:e4586.  DOI:  10.7717/peerj.4586

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