Leptolalax (Lalos) pelodytoides ( Boulenger, 1893 )

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 : 28-31

Leptolalax (Lalos) pelodytoides ( Boulenger, 1893)

( Fig. 7 – 8 )

Leptobrachium pelodytoides Boulenger, 1893: 345 , pl. 11.

Onymophoront: Lectophoront (lectotype) by subsequent designation of Capocaccia (1957: 212), MSNG 29845 .A, adult female .

Onymotope: Thao [Thamo] (17°08’ N, 98°01’ E), Kayah State, Myanmar. Collected by Leonardo Fea , 1885 .

Material examined. Myanmar: Thao, Karin Hills: BMNH 1947.2.25.14, exonymophoront, adult male; MSNG 29845.A, lectophoront, adult female, coll. Leonardo Fea, 1885; — Karin Bia-po (800–1000 m): MSNG 29845.B, adult female, exonymophoront, coll. Leonardo Fea, 1885; — Carin Ghecú [Caim Gheena, near Thao] (1300–1400 m): MNHN 1893.519, adult male; ZMB 11588, adult male, coll. Leonardo Fea, 1885; ZMH A02413 , adult male, coll. Leonardo Fea, 1885.

Comment. Boulenger (1893) described the species based on three specimens: two from Thao and one from Karin Bia-po (near Leiktho: 19°13’ N, 96°34’ E; 800–1000 m; Kayin State), Myanmar. He presented a figure of specimen BMNH 1947.2.25.14, adult male, which is now an exonymophoront. Capocaccia (1957: 212) designated the female specimen MSNG 29845.A from Thao as lectophoront of this nominal taxon. The two specimens show some difference in colour pattern and morphology. The lectophoront designation of Capocaccia created some taxonomic problems as she did not choose the figured specimen as lectophoront as recommended by the International Code of Zoological Nomenclature: most taxonomists only have access to this figure and the description of Boulenger. But the species is now defined by the lectotype, and the following description of the lectophoront and the figure of the specimen will make the characters of the species available to the community of taxonomists.

The first described species nomen available for the genus Leptolalax , Ixalus lateralis Anderson, 1871 , is allocated to a species which is known from its onymotope in Nagaland ( India) only ( Humtsoe et al. 2008), and which is different from all other known species of the genus. In particular, it is distinct from Leptobrachium pelodytoides Boulenger, 1893 as defined by the hypodigm by several consistent differences, including a smaller head in L. lateralis than in L. pelodytoides . These species can also be distinguished by the webbing, which is quite distinct in L. pelodytoides but rudimentary in L. lateralis ( Humtsoe et al. 2008) .

L. pelodytoides was described from Myanmar and no onymotopic material has been collected recently as the onymotope is in a part of the country which has been closed to scientists for many years. Thus only study of the original symphoronts can provide information on the identity of this species.

The name pelodytoides has been used for many populations of Leptolalax from China, Vietnam, Laos, Thailand and Myanmar. Our molecular data show that several clades can be recognized within the populations called pelodytoides . Morphological analysis (tables 3−5) and analysis of colour pattern (see below) give evidence that the nomen Leptobrachium pelodytoides should be applied to specimens from the Karin Hills only. Thus all other specimens mentioned as L. pelodytoides in the literature should be allocated to other taxa.

Diagnosis. Leptolalax pelodytoides is a member of the subgenus Lalos based on the presence of a lateroventral gland and distinguished from other species included in this subgenus by the following combination of characters: large-sized species (males 27.5–32.3 mm; females 35.5–37.8 mm) ( Table 3) with small webbing on feet and narrow fringes on toes; distinct tympanum; dermal ridges under toes poorly distinct; finger tips slightly dilated; dorsum with glandular warts and short elongate ridges (Table 4); dorsal pattern distinct including dark outlines on warts and foldings; large dark spots on flanks present; ventral side whitish; iris colour in life not known ( Table 5).

Description of lectophoront. Size and general aspect. (1) Specimen of moderate size (SVL 37.8 mm), body rather slender.

Head. (2) Head of medium size, narrower (HW 12.2 mm) than long (HL 13.0 mm; MN 11.3 mm; MFE 8.5 mm; MBE 4.5 mm), flat. (3) Snout slightly protruding, its length (SL 5.7 mm), longer than horizontal diameter of eye (EL 4.3 mm). (4) Canthus rostralis distinct, loreal region concave, vertical. (5) Interorbital space flat, about as large (IUE 3.4 mm) as upper eyelid (UEW 3.5 mm) and internarial distance (IN 3.2 mm); distance between front of eyes (IFE 5.7 mm) more than half of distance between back of eyes (IBE 9.7 mm). (6) Nostrils oval, about as close to tip of snout (NS 2.6 mm) as to eye (EN 2.5 mm). (8) Tympanum (TYD 2.1 mm) distinct, rounded; about equal to half eye diameter, tympanum-eye distance (TYE 1.6 mm) three-fourths of its diameter. (11) Tongue not observed.

Forelimbs. (12) Forearm rather long, thin (FLL 9.0 mm), about length of hand (HAL 9.1 mm), not enlarged. (13) Fingers rather long and thin (TFL 4.7 mm). (15) Tips of fingers slightly enlarged. (16) Fingers without dermal fringe.

Hindlimbs. (19) Shanks about four times longer (TL 16.4 mm) than wide (TW 3.8 mm), about as long as thigh (FL 16.9 mm) and distance from base of internal metatarsal tubercle to tip of toe IV (FOL 16.2 mm). (20) Toe IV (FTL 7.8 mm) about one-third of distance from base of tarsus to tip of toe IV (TFOL 23.6 mm). (22) Tips of toes not enlarged. (23) Webbing small: I 2 – 2 ½ I 1 ½ – 3 III 2 ½ − 3 ¾ IV 4 – 3 V (MTTF 6.5 mm; MTFF 6.2 mm; TFTF 8.8 mm; FFTF 9.9 mm). (24) Narrow fringe along toes present. (26) Inner metatarsal tubercle short, distinct; its length (IMT 1.5 mm) 2.3 times in length of toe I (ITL 3.5 mm).

Skin. (29) Dorsal and lateral parts of head and body: snout and region between the eyes with small glandular warts, side of head smooth with horny spinules; back with glandular folds on shoulder and side of back forming discontinuous ridges, flanks with glandular warts. (30) Supratympanic fold distinct, from eye to above shoulder. (31) Dorsal parts of forelimb, thigh and tarsus smooth, leg with few glandular warts. (32) Ventral parts of head, body and limbs: throat, chest, belly and thigh smooth. (33) Presence of macroglands: lateroventral gland present as short continuous glandular ridge in anterior part of flank continuing as separate glands in line; large femoral and axillary glands; relatively smaller suprabrachial glands.

Coloration. In alcohol. (34) Dorsal and lateral parts of head and body: brown with indistinct darker outline on warts and ridges; lower part of flanks greyish brown with 8 on the left, 10 on the right, large brown spots; tympanic region brown with blackish brown line on tympanic fold; upper lip light brown with dark brown bands. (35) Dorsal parts of limbs: proximal part of forelimbs light beige, distal part slightly darker with brown crossbands; dorsal part of thigh, of shank and of foot light brown with indistinct, incomplete darker brown crossbands; posterior part of thigh beige with large distinct dark brown spots. (36) Ventral parts of head, body and limbs: dirty white with fine brown spots on margin of throat; webbing light brown.

Sexual characters. (40) Oviduct convoluted. (41) Ovary with large creamy-whitish oocytes.

Variation. The female lectophoront MSNG 29845. A shows a poorly distinct darker zone on snout, an indistinct triangle between eyes and spots and lines outlining the warts and ridges on dorsum. The basic dorsal colour is brown. The flanks are covered by a series of small black spots. The venter is whitish with brown spots on the bor- der of throat and the shanks are brown coloured in their posterior part. The male exonymophoront BMNH 1947.2.25.14 figured by Boulenger (1893) shows snout spots and a triangle between the eyes linked to the shoulder spots; a single spot is present in the anterior and another spot in the posterior part of the iliac region; these spots show a fine outline. The flanks show a series of dark rather large-sized distinct spots. The warts appear lighter than the back but their dark outline is not visible in drawing. Boulenger (1893) mentioned that the throat of the male was dark-coloured but the chest and belly were white. The presence of femoral glands was mentioned as presence of “a round white dark-edged spot”. The lectophoront and the exonymophoront show many differences in dorsal pattern. The colour pattern of the male is unique among all specimens of Leptolalax studied. Beside these two specimens, a single specimen of L. ventripunctatus and two specimens of L. aereus from Vietnam also show a spot on the snout but in these specimens the snout spot is not confluent with the triangle between eyes and with the shoulder spot.

Boulenger (1893) described the webbing as “one third webbed”. As Boulenger did not explain the significance of terms used, the descriptions in Boulenger (1882) were screened to find species that have similar qualifiers to describe their webbing. Rana tuberculosa Boulenger, 1882 , now Tomopterna tuberculosa , a South African anuran species, is “one third webbed”. In this species 3 ½ to 4 phalanges of toe IV are free of webbing ( du Preez & Carruthers 2009). As for a species with very small webbing, L. gracilis , as Leptobrachium gracile in Boulenger (1882) is described as “slightly webbed” by Boulenger (1882), as having “a very short basal membrane” by Günther (1872), and as “webbing only at base of toes” by Inger & Stuebbing (2005). Thus our finding of 3 ¾ and 4 phalanges of toe IV free of web in L. pelodytoides is consistent with Boulenger’s description.

Distribution. Myanmar: “Karin Hills” ( Fig. 9 ).

Natural history. No habitat information was given in the original description, nor other observations on natural history. The species has not been collected since its original description.

Etymology. Resembling a Pelodytes , the small European pelodytid toad. Invariable adjective in apposition to generic substantive.

Placement in molecular phylogeny. No samples available for molecular study.

Conservation status. This species as understood here is only known from the type locality and adjacent localities in Myanmar based on the original description. There are no recent data on L. pelodytoides and on its habitat available. We propose therefore to change its Red List status from Least Concern to Data Deficient .

Figures

FIGURE 7. Leptolalax pelodytoides, MSNG 29845.A, lectophoront, adult female, SVL 37.8 mm. (A) Dorsal and (B) ventral view.

FIGURE 8. Leptolalax pelodytoides, MSNG 29845.A, lectophoront, adult female. (A) Lateral view of head, ventral view of (B) right foot and of (C) right hand. Scale bar = 5 mm (3 + 2 mm).

FIGURE 9. Distribution of localities of specimens of subgenus Lalos studied in this work. Onymotopes are indicted as stars. Olive green—pelodytoides; blue—L. minimus form 2; orange yellow—L. minimus; red—L. aereus; grey—L. eos; light green – L. ventripunctatus; white—L. bourreti; black—L. pluvialis; yellow—L. nyx.