Boulenophrys shimentaina (Lyu, Liu & Wang, 2020)

Qian, Tianyu, Li, Yonghui, Chen, Jun, Li, Pipeng & Yang, Daode, 2023, Tadpoles of four sympatric megophryinid frogs (Anura, Megophryidae, Megophryinae) from Mangshan in southern China, ZooKeys 1139, pp. 1-32 : 1

Boulenophrys shimentaina

Fig. 2

Remark.

The following description is based on five tadpoles at Stages 25-28 (N = 5). Body ratio ranges represent all specimens. Raw measurements are given in Table 1 .

Specimens examined.

CSUFT T10156 (Stage 25; Field voucher: MT06; GenBank accession number: ON209270 ) collected on 30 May 2021 from Tiantaishan (24.972277°N, 112.963394°E, ca. 1280 m a.s.l.), Mangshan , Hunan Province, China ; and CSUFT T10277 (Stage 26, Field voucher: MT707; GenBank accession number ON209281 ), CSUFT T10279 (Stage 26; Field voucher: MT709; GenBank accession number: ON209264 ), CSUFT T10283 (Stage 28, Field voucher: MT713; GenBank accession number: ON209261 ); and CSUFT T10285 (Stage 27; Field voucher: MT715; GenBank accession number: ON209272 ) collected on 14 July 2021 from Xiangsikeng (24.937705°N, 112.990257°E, ca. 1530 m, a.s.l.), Mangshan , Hunan Province, China .

External morphology.

The body is oval and flattened above (BW/BL 51.3-55.0%, N = 5); the eyes are located dorsolaterally, and the pupils are round; the nares are oval, open laterally, closer to the eye than to the tip of the snout (NE/SN 62.5-71.4%, IND/IOD 67.6-71.9%, N = 5); the rims of nares are serrated, slightly raised from the body wall; the spiracle is sinistral, low on the left flank; the spiracle tube is short, free from the body at the tip and opens laterally (SS/BL 53.4-58.0%, N = 5); the anal tube opens medially, unattached to the ventral fin; the dorsal fin arises behind the body-tail junction while the ventral fin is connected to the trunk; the tail muscle is massive, taller than tail fins before reaching the 2/3 part of the tail length (TMH/MTH 50.0-55.6%, N = 5); the tail tip is bluntly pointed, the tail length accounts for 69.5-76.1% (N = 4) of the total length; the mouth is terminal and the oral disc is funnel-like (BW/ODW 65.2-77.2%, N = 5); four rows of oval submarginal papillae are visible on the upper lip, and five rows of oval submarginal papillae on the lower lip; keratodonts are absent; the upper jaw sheath is comb-like, exhibiting a small median notch; the lower jaw sheath is thin and sickle-shaped, weakly keratinized, and finely serrated.

Coloration.

The following description is based on a tadpole at Stage 27 (CSUFT T10285). In life, the background color of the body and tail is semi-transparent dark brown; the dorsum is pigmented pale brown which extends to the dorsal surface of anterior tail and gradually becomes golden; a distinct circled marking is present at the center of dorsum, forming a saddle with the background dark brownish coloration; the middle of the saddle is pigmented pale brown; and the neuromasts are distinctly visible. Laterally, the dorsal pattern extends to the region above the horizontal level of the spiracle on the trunk, and covers the whole lateral surface of head; the lateral surface of tail is pigmented brown; the tail and fins are covered with irregularly shaped pale golden spots, interspersed with dense dark brown speckles; the fins are semi-transparent; the anterior part of the dorsal fin is marbled with golden and dark brown speckles; the junction of the anterior half of the dorsal fin and the caudal muscle is pigmented dark brown, forming an incomplete line; the anterior part of the ventral fin and the anal tube exhibit minimal dark brown pigmentation; the posterior part of tail and fins are pigmented with dense dark brown markings. The ventral body is semi-translucent grey, pigmented with dark brown chromocytes, and is covered with dense small, indistinct milky-white speckles; the gills and gut coils are visible through the ventral skin; two large, milky-white spots are present on each side of the ventrolateral surface of head-body connection and are followed by a cluster of smaller spots. The oral disc is translucent milky white; the lateral and middle wings are covered with orangish pigmentation; the tips of the wings and the middle of the upper lip exhibit dark brown pigmentation; the submarginal papillae on lips are dark brown, and the narial rims are pigmented beige. The eye sclera is silver with black dots; the iris is orange sprinkled with black dots; and the spiracle is translucent without pigmentation.

Variation of coloration in life. The other four tadpole specimens match most of the descriptions above. However, the dorsum pattern of a saddle is not clearly visible in CSUFT T10156 and the dorsum is almost uniform pale brown in CSUFT T10177. The ventrolateral spots on head-body connection are very large in CSUFT T10283 (Stage 28, Fig. 2F ), but smaller in CSUFT T10277 (Stage 26, Fig. 2E ).

In preserved specimens, the pale brown pigmentation on the dorsal surfaces of the body and tail are still visible; the golden and orangish pigmentation fade to milky white; the white spots on each side of the ventrolateral surface of head-body connection become translucent; there is no orange pigmentation on the mouthparts, and prominent black pigmentation can be observed on the tail.

Comparisons.

The two distinct, conspicuous ventrolateral spots on ventrolateral surface of head-body connection could distinguish the tadpoles of Bo. shimentaina from most Boulenophrys tadpoles, including Bo. fansipanensis , which have a single spot visible on each side, and Bo. rubrimera , Bo. hoanglienensis , Bo. jingdongensis , Bo. leishanensis , Bo. jiangi , and Bo. lushuiensis with no ventrolateral spots; the ventral pattern of indistinct, small speckles on belly could distinguish Bo. shimentaina tadpoles from Bo. lini , which have dense large speckles (see Wang et al. 2014: fig. 5F). Furthermore, the tadpoles of Bo. shimentaina differs from Bo. lushuiensis by having a silver sclera with black dots (vs. black with golden pigments); and from Bo. baishanzuensis by having a pale brown pattern on dorsum (vs. uniformly brownish black).

Tadpoles of Bo. shimentaina could be distinguished from the syntopic Boulenophrys tadpoles in Mangshan (see below for the descriptions) by having a dark brown background coloration of body and tail (vs. pale brown in Bo. cf. ombrophila and Bo. nanlingensis ), and a tail pattern of dense dark brown markings posteriorly (vs. several large brown spots along tail muscle in Bo. cf. ombrophila ; and many brown speckles in Bo. nanlingensis ). Further comparisons between Bo. shimentaina tadpoles and all megophryinid tadpoles identified based on molecular data are shown in Tables 2 , 3 .

Ecology notes.

A single tadpole at Stage 25 was collected on 30 May 2021, together with the tadpoles of Bo. nanlingensis and Br. popei from the road ditch (Fig. 5C ) that was mentioned above in the Br. popei section. Four tadpoles at Stages 25-28 were collected together with tadpoles of Bo. nanlingensis and Bo. cf. ombrophila from a rocky, slow-flowing narrow stream (Fig. 5B ) on 14 July 2021 at 23:20 h while nearby adult males were calling. As this stream is located near the mountain top, it is narrow and slow. There were low trees and bamboo on both sides of the stream, and many fallen logs lay across the stream with a rocky stream bed. This site was used by many species as a breeding site including Bo. nanlingensis , Bo. shimentaina , Br. popei , Leptobrachella mangshanensis (Hou, Zhang, Hu, Li, Shi, Chen, Mo & Wang, 2018), and Quasipaa exilispinosa (Liu & Hu, 1975). The tadpoles of Bo. shimentaina found in this stream were observed at night in an area with sandy substrate near the stream bank or in still water behind a small dam formed by submerged leaf litter. Sunlight could reach the surface of these areas at certain times during the day. While feeding beneath the water surface, the tadpoles rely on submerged leaf litter or rocks (Fig. 5A ). Once disturbed, they hid quickly under the submerged leaf litter and emerged from the leaf litter after several seconds. In the still water area where these tadpoles were found, we also encountered many Q. exilispinosa tadpoles on the stream substrate, and a subadult newts, Pachytriton xanthospilos Wu, Wang & Hanken, 2012, hiding under submerged leaf litter. Male Bo. shimentaina frogs were observed calling from late June to August in Mangshan, and it was suggested that the breeding season of Bo. shimentaina is from April to August in Shimentai Nature Reserve, Guangdong Province ( Lyu et al. 2020). It is not clear if tadpoles complete metamorphosis within a single year, and we didn’t collect any tadpoles of more advanced developmental stages.

Figures

Figure 2. Boulenophrys shimentaina tadpoles A-C freshly dead tadpole CSUFT T 10285 (Stage 27) lateral view, dorsal view, and ventral view D oral disc of tadpole CSUFT T 10283 (Stage 28) in life E ventral pattern of tadpole CSUFT T 10277 (Stage 26) in life; and F ventral pattern of CSUFT T 10283 (Stage 28) in life. E and F share the same scale bar with A-C.

Figure 5. Megophryinid tadpoles and their habitats in Mangshan, Hunan Province, China (A) Non-collected Bo. shimentaina tadpole (middle) feeding together with two unrecognized tadpoles in its habitat (B); and tadpole habitat (C) of a mixed-species assemblage beside a forest road, with unrecognized tadpoles feeding together (D).