Leptolalax (Lalos) oshanensis ( Liu, 1950 )

Ohler, Annemarie, Wollenberg, Katharina C., Grosjean, Stéphane, Hendrix, Ralf, Vences, Miguel, Ziegler, Thomas & Dubois, Alain, 2011, Sorting out Lalos: description of new species and additional taxonomic data on megophryid frogs from northern Indochina (genus Leptolalax, Megophryidae, Anura) 3147, Zootaxa 3147 (1), pp. 1-83 : 31-32

Leptolalax (Lalos) oshanensis ( Liu, 1950)

Megophrys oshanensis Liu, 1950: 13 , 197.

Onymophoront, by original designation as “type”: holophoront (holotype), Liu Collection 1000 (now CIB 1000 ), adult male, SVL 27.0 mm ( Liu 1950: 197–198) .

Onymotope: Emei Shan (29°35’ N, 103°11’ E; alt. 1070 m), Sichuan, China. Collected by Liu Ch’eng-chao, 10 June 1945 .

Comment. Leptobrachium minimum was considered a synonym of Megophrys oshanensis by Dubois (1981), but in the genetic analysis, onymotopic specimens of both species appear in distinct clades ( Fig. 4 ). Thus we recognize them as a distinct species. The name L. oshanensis should be restricted to Chinese populations. Here we give data from the original description ( Liu 1950), from Fei & Ye (1992) and Fei (1999) for morphological diagnosis. Molecular evidence from sequences deposited in GenBank would indicate that the species as currently defined is not monophyletic. Further studies should be conducted to confirm these results as the sequences here included are from GenBank without indication of voucher specimens.

Diagnosis. Member of the subgenus Lalos based on the presence of lateroventral glands and molecular phylogenetic relationships ( Fig. 4 ), distinguished from other species included in this subgenus by the following combination of characters: moderate-sized species (adult males 26.6–30.7 mm) ( Table 3) without webbing between toes, without lateral fringes on toes, with distinct tympanum; thin irregular glandular ridges on back (Table 4); back reddish brown with pattern including a triangular spot between eyes and lighter glandular spots near vent; a few large dark spots on flanks; throat with dots, belly uniformly white ( Table 5).

Description of holophoront (rearranged from original description of Liu 1950; numerous characters missing): Size and general aspect. (1) Specimen of small size (SVL 27.0 mm), body moderately stout.

Head. (2) Head of medium size, as broad (HW 9.5 mm) as long (HL 9.5 mm). (3) Snout slightly protruding; (eye length EL 4.0 mm). (4) Canthus rostralis well defined, loreal region concave, oblique. (6) Nostrils closer to tip of snout than to eyes. (8) Tympanum visible (TYD 1.9 mm). (11) Tongue large, deeply notched.

Forelimbs. (12) Forearm moderately slender (FLL 13.0 mm; HAL 7.0 mm). (14) Relative length of fingers, shortest to longest: I <II = IV <III. (15) Tips of fingers rounded, slightly enlarged. (17) Subarticular tubercles absent, but third finger with pad-like elongated elevations. (18) Inner metacarpal tubercle very large, outer one very small.

Hindlimbs. (19) Hindlimbs thin (TL 12.0 mm); (FOL 11.5 mm); (TFOL 18.0 mm). (23) Webbing absent. (25) Toes ventrally with elongated pad-like elevations. (26) Inner metatarsal tubercle well developed. (28) Outer metatarsal tubercle absent.

Skin. (29) Dorsal and lateral parts of head and body: snout, region between eyes and side of head smooth; back with glandular ridges; a few light-coloured warts distributed around vent. (30) Supratympanic fold well-developed, from eye extending postero-ventral to shoulder region. (32) Ventral parts of head, body and limbs: throat, chest, belly and thigh very smooth. (33) Presence of macroglands: lateroventral gland composed of white glands arranged in rows between axilla and groin; large oval suprabrachial and femoral glands present.

Coloration. In life: (34) Dorsal and lateral parts of head and body: Reddish brown all over body with a black triangular mark on back of head, with a few black bars on mouth, and scattered black spots on body. (35) Dorsal parts of limbs: black bars distinctly developed. In alcohol: after preservation, the reddish brown becomes greyish brown. (36) Ventral parts of head, body and limbs: throat with irregular dots, belly without spots.

Male secondary sexual characters: (38) Vocal sacs: no outer modification of skin; paired internal subgular vocal sacs.

Distribution. China: Guizhou Province, Hubei Province, Sichuan Province.

Natural history. As described by Liu (1950: 199): “ L. oshanensis was found under stones in corn fields on hillsides at about 3500 feet. Adults are difficult to find, as I got only two specimens of adult males in three summer’s work. Tadpoles are very abundant in small mountain streams.” The species is known to occur in mountain areas from 700 to 1800 m. Tadpoles were collected from side pools, in pools beneath cascades, on the bottom of pools, in cracks between stones, hiding in vegetation or roots of bamboos and trees at the margin of the water. They stay in shallow running water with the head directed up-stream and the tail curved like an eel (Fei & Ye 1992).

Etymology. Adjective as epithet of generic nomen (same grammatical gender), meaning “from O Shan ”, i. e., from Emei Shan, a famous mountain in Sichuan.

Placement in molecular phylogeny. Specimens allocated to Leptolalax “ oshanensis ” do not form a monophyletic group. They are members of a highly supported clade that groups L. eos , L. bourreti and Leptolalax sp. from Doi Chiang Dao. L. “ oshanensis ” AY561306 , from the onymotope, and thus probably “true” oshanensis , is sister to L. eos whereas L. “ oshanensis ” AY526215 is sister to Leptolalax sp. from Doi Chiang Dao. Further studies are needed to reliably allocate the name oshanensis to probably one of these mitochondrial lineages and to describe the other of these mitochondrial lineages as new species.

Conservation status. We confirm the Red List status of this species as Least Concern. In the future, L. oshanensis might be dismantled into various species and then a re-evaluation will be needed.

Figures

FIGURE 4. Combined 16SrRNA Bayesian phylogeny and haplotype networks of 113 Leptolalax specimens with hierarchical outgroups (schematic representation in the grey box) The tree topology corresponds to the Bayesian topology obtained with three million generations, values on nodes indicate posterior probabilities (asterisks> 95 %, double asterisks> 99 %), and Maximum Likelihood bootstrap support values (> 70 %). Red numbers are the percentage of uncorrected p - sequence divergence between selected sister clades. Minimum spanning haplotype networks for two Leptolalax-clades (connected to phylogenetic tree nodes marked grey) were obtained with TCS. Numbers on haplotype connections represent number of nucleotide substitutions. Numbers of specimens included in haplotype networks are: B5-1(12); B5-2(17); B5-3(6); B5-4(1); B4-1(8); B4- 2,3,4,7,8(1); B4-5(2); B4-6(3). Sampling localities are provided as pie charts within haplotype circles, circle size corresponds to the number of sampled individuals. Abbreviations for country of origin are as follows: L—Laos, M—Malaysia, T—Thailand, V—Vietnam. Newly described species and haplotype networks are coloured.