Hylarana guentheri Boulenger 1882

Hylarana guentheri (Boulenger, 1882)

Series examined. Tadpoles of Hylarana guentheri (ZFMK 86987-86988: n = 18) were collected in PNKB, Cha Noi region, Vietnam by R. Hendrix from June to August 2006. The larvae were collected throughout day and night time in ponds (bomb craters) in a paddy field and at the forest edge at an altitude of about 300 m above sea level.

An adult specimen (ZFMK 86372) was collected at night near a forest stream within Cha Noi region of PNKB, Vietnam, at an altitude of about 300 m above sea level.

Identification. The adult specimen (Fig. 1c) largely agreed with the description provided by Ziegler (2002). Sequence congruence between the adult specimen (ZFMK 86372) and tadpoles (ZFMK 86987, 86988; Fig. 2c) was 100 %. The following larval description is based on a single tadpole in Gosner stage 27 (Fig. 5; for measurements see Table 6). The tadpole specimen used for description and drawing originates from the same water body as the DNA voucher specimen. In this water body, no other Hylarana species were observed. The DNA voucher specimen was destroyed for DNA extraction but examined morphologically before this procedure, and it fully agreed morphologically with the described and drawn specimen in the diagnostic characters (narrow upper jaw sheath, cone-shaped marginal papillae, one submarginal row of papillae, papillae unpigmented, silver-white colour with dark dorsoventral stripe). The identification of the described specimen is therefore well supported.

– Ke Bang National Park, Cha Noi region, Vietnam (ZFMK 86987-86988); for abbreviations see material and methods.

27 (1.34 ±0.13) (1. 4 7 (0. 5 5 (4. 7 3 (9. 53 (15. 6 2 (1. 43 (1.45 ±0.11) (1. 0 2 ±0.20) ±0.09) ±0.67) ±0.97) ±2.03) ±0.16) ±0.15) (n=10) (n=10) (n=10) (n=10) (n=10) (n=10) (n=10) (n=10) (n=10)

28 1.4 1.5 0.5 5.5 11.7 19.0 1.7 1.7 1.0 Colour pattern. Colouration of tadpole in preservative: body glassy-white. Pigmentation is strongest from tip of snout to anterior corner of the eye. Behind the eyes, the body is covered with triangular blotches. Furthermore, the body is covered with densely pigmented blotches in the nares region, laterally in the intestinal coils region and ventrally around the heart. Tail slightly pigmented.

Colouration in life: body silver to white, with a short dark stripe from the nostril to the anterior corner of the eye and with a dark fleck behind the eye. Tail fin silver to white with small blotches. Ventral side of body is grey, intestinal spiral is slightly visible.

Description in dorsal view: Body is oval shaped (maximum body width 0.64 of body length; body length 0.64 of tail length) with a pointed snout. Eyes of remarkable size (maximum diameter of eye 0.15 of body length), dorsolaterally directed and positioned at the beginning of the second third of the body. Interpupilar distance 0.83 of maximum body width. Nares slightly rimmed, anterolaterally positioned and directed. Nares are closer to the tip of snout than to pupil (rostro-narial distance 0.41 of naro-pupilar distance). Internarial distance 0.51 of interpupilar distance. Tail musculature is of moderate size (width of tail musculature at base 0.37 of maximum body width).

Description in lateral view: In lateral view body depressed (maximum body height 0.81 of maximum body width), with pointed snout. Spiracle is tubular-shaped, sinistral, laterally positioned and attached to the body wall. Spiracular opening is round, and closer to the end of body than to the snout. Body length 0.63 of tail length. Height of tail musculature at base 0.97 of tail musculature width. Tail musculature is gradually tapering from the proximal to the distal end. Myotomes of tail are V-shaped and from the second third of the tail onwards separated by broad myosepts. Upper fin of tail situated at the base of tail, slightly convex. Maximum height of lower fin 0.78 of maximum height of upper fin. Vent tube is located ventromedially; the cloacal aperture is dextral in dorsal view. Outer wall of vent tube adhered to lower tail fin.

Oral disc. Oral disc anteroventrally positioned, trapezoidal, emarginated (oral disc width 0.38 of maximum body width) and nearly surrounded by marginal cone-shaped papillae. Upper labium with large medial gap without papillae. Marginal papillae of the lower labium elongated. Two or three submarginal papillae situated in the corner of the mouth, one row of submarginal papillae situated at the lower labium under the last keratodont row. Keratodont row formula 2(2)/3(1) or 1/3(1). Upper and lower beaks black, with low and fine serrations. Upper beak is M-shaped, wide with short appendices, lower beak V-shaped.

Glandular Zones. Areas with high density of secretory glands are not discernible.

Measurements (in mm). BH 3.2±0.2; BL 6.1±1.3; BW 3.9±0.3; ED 0.9±0.1; IND 1.5±0.1; IP 3.2±0.2; LF 0.8±0.1; NP 31±5; NPD 1.3±0.1; ODW 1.5±0.2; RND 0.6±0.1; TAL 9.5±1.0; TMH 1.4±0.2; TMW 1.5±0.1; UF 1.0±0.2.

Variation within the series. Series with 18 tadpoles in stages 25–30. Proportions vary as follows: BW 0.54–1.35 of BL, ED 0.13–0.29 of BL, IP 0.74–0.90 of BW, RND 0.31–0.50 of NPD, IND 0.42–0.60 of IP, TMW 0.30–0.43 of BW, BH 0.71–0.90 of BW, TAL 1.09–2.88 of BL, TMH 0.35–0.53 of BH, TMH 0.42–0.56 of MTH, UF 0.27–0.40 of MTH, LF 0.57–1.33 of UF, ODW 0.29–0.44 of BW. Keratodont row formula 2(2)/3(1) or 1/3(1). General morphology and colouration in stages 25–30 is homogenous within the series.

Previous descriptions. In comparison to the data provided by Pope (1931) for larvae from Nodoa, China (at about stage 39) our series differed only slightly. In our tadpoles, tail fins measured about 1.5 of body length, whereas the tail fins measured at least 2.0 of body length in the Chinese larvae. The first keratodont row P1 of the lower labium is only slightly interrupted according to Pope’s (1931) description for Chinese larvae, whereas P1 is distinctly interrupted within the tadpoles from Phong Nha – Ke Bang, Vietnam.

Natural history. Larvae of H. guentheri were collected in a bomb crater next to a rice field in Phong Nha village and in a bomb crater near the forest edge at Cha Noi region between 10 and 14 August 2006. The larvae were found near the shore area in the shallow water on the sandy ground between leaves, plants and in part also waste. Adults were seen near water bodies in anthropogenic areas such as rice fields, grassland, waysides or forest clearings especially throughout or after rain falls in altitudes up to 300 m a.s.l. Sporadical mating calls of males were heard in the dry season but increased with the begin of the rainy season. Spawn was detected as a layer on the water surface of a pond in early July 2006. The yellow-black eggs measured 1.5–2 mm in diameter.