Megophrys medogensis Fei et al., 1983

Shi, Shengchao, Zhang, Meihua, Xie, Feng, Jiang, Jianping, Liu, Wulin, Li Ding,, Luan, Li & Wang, Bin, 2020, Multiple data revealed two new species of the Asian horned toad Megophrys Kuhl & Van Hasselt, 1822 (Anura, Megophryidae) from the eastern corner of the Himalayas, ZooKeys 977, pp. 101-161 : 101

Megophrys medogensis Fei et al., 1983 Figs 3B, G, L, Q, V , 4A, D, G, J , 5B, G , 6A, B, E, F, I, J, M, N , 10A-C, E, F , Suppl. material 2: Figs S1, S5A-H; Tables 1 , 2, 3, 4, Suppl. material 1: Table S1-S5

Megophrys omeimontis medogensis Fei, Ye and Huang (1983)**: 49-52.

Specimens examined.

Five adult females and six adult males from Medog (Suppl. material 1: Table S1).

Holotype description.

Refer to Fei et al. (1983) for holotype description, Mahony et al. (2018) for picture of holotype CIB 73II0015, Fei et al. (2009) and Fei and Ye (2016) for description of coloration and picture of topotypes.

Skull. (Fig. 5B, G ). Description based on sequenced adult male topotype CIB022017061406. Skull well ossified, width 1.21 × length; maxillary overlapping with the quadratojugal; premaxillary and maxillary teeth well developed, and closely positioned with others, 11/13 teeth present on left/right of premaxillary; vomerine ridge robust; few vomerine teeth strong, present on posterior end of vomerine ridge; nasal process of premaxilla protruding beyond skull; nasal bones separated, posterior one third of inner edge contact with sphenethmoid; frontoparietal distinctly wider in front than rear; sphenethmoid relatively smooth with few small pits on dorsal and ventral surface, the middle half of front edge not contacting nasal bones and protruding forward, separated from premaxilla; frontoparietal not divided, sagittal suture occlusive; anterior fontanelle occlusive; front part of frontoparietal distinctly wider than rear; posterior edge of exoccipitals anterior to the line connecting conjunctions of quadratojugal and mandible; pterygoid robust; anterior process of squamosal slender, tip much closer to the junction of pterygoid and quadratojugal than its base, posterior process present; prootic relatively smooth, separated from exoccipitals; anterior process of parasphenoid in shape of fusiform, the front part raise above sphenethmoid from ventral view, the conjunction with sphenethmoid with width equals the constriction near base of anterior process of parasphenoid; columella slender and long.

Secondary sexual characters.

Adult female generally with larger body size. Average body length females 79.7 mm (n = 5, 75.7-85.5 mm), male 65.3 mm (n = 6, 63.1-68.7 mm). Males with brown nuptial pads on fingers I and II, spines on nuptial pad dense; single subgular vocal sac.

Tadpole.

(Fig. 6A, B, E, F, I, J, M, N ; Suppl. material 1: Table S2). For low-middle-elevation tadpoles of M. medogensis , description was based on tadpole CIBMT20170621 (stage 35) which shared the same pond of sequenced tadpole CIBMT022017061808 in Bari village. They are similar on morphology. For coloration at stage 26, description based on sequenced specimen CIBMT1710101 from Yadong village. Measurements in mm. For stage 35, body 13.3, elongated; head slightly narrower than trunk, oral disk large, funnel like, 1.2 × body width; three rows of short oval submarginal papillae on lower lip; middle of lower lip protruding forward, with five rounded papillae longitudinal arranged from the tip middle lower lip to oral cavity; corner of mouth with six papillae arranged in a transverse row on both sides; three transverse rows of short oval papillae on upper lip; keratodonts absent; nares closer to eyes than tip of snout (RN/NE 1.6); eyes round, positioned dorsolaterally; internarial distance (IND 3.0) 61% of the interpupilar distance (PP 4.9); spiracle mostly in left side of body, in right-handed helix from ventral view; spiracular tube not protruding beyond body wall, positioned 60% of the distance between tip of the snout and trunk-tail junction, and below the horizontal mid trunk line; tail accounts 69% of total length; dorsal fin arise above trunk-tail junction, 35% of maximum body height; ventral fin connected to the trunk, with lesser height, 27% of maximum body height; anal siphon opens medially; maximum tail muscle height 72% of maximum body height, maximum tail muscle strong, width 53% of maximum body width; 12 small curves present on both lateral side of tail muscle. For stage 26, dorsal fin arises behind trunk-tail junction. For stage 43, clear “X” and “l_l” skin ridges have present on dorsum, limbs are well developed. For high-elevation tadpoles of M. medogensis , description mostly based on sequenced tadpole CIBMT171001 (at stage 27), coloration based on sequenced tadpoles CIBMT1710106 and CIBMT1710112, collected from Gedang, Medog, Tibet Autonomous Region, China (29.463916°N, 95.769507°E, 2142 m). Body 9.5, elongated; head slightly narrower than trunk; oral disk moderate, funnel like, positioned anterior-dorsal, width equal with body width; 5 transverse rows of short oval papillae on upper lip; keratodonts absent; nares much closer to eyes than tip of snout (RN/NE 2.2); eyes round, positioned dorsolaterally; internarial distance (IND1.9) 61% of the interpupil distance (PP 3.2); spiracle barely visible from ventral view; the spiracular tube not protruding beyond body wall, positioned 63% of the distance between tip of the snout and trunk-tail junction, and below the horizontal mid trunk line; tail accounts 72% of total length; dorsal fin arise above anal siphon opens, 40% of maximum body height; ventral fin connected to the trunk, with lesser height than dorsal fin, 37% of maximum body height; anal siphon opens medially; tail muscle relatively weak, maximum height 72% of maximum body height, width only 44% of maximum body width; eleven small curves present on both lateral side of tail muscle.

Coloration of tadpoles. Low-middle-elevation tadpoles. In preservation (based on CIBMT20170621; Fig. 6A, B, E, F ): dorsal body brown; lips semitransparent, papillae on lips brown; dorsal tail light brown, marbled with deep brown markings; lateral side of tail densely covered with tiny brown pigment spots, also mottled with small light colored patches, and scattered with deep brown pigments piles; fins semitransparent; ventral surface of body semitransparent, sparsely covered with brown pigments. In live: dorsal and lateral body generally in light yellow-brown; lateral side of tail mottled with light colored patches; ventral body without white patches; iris brown.

High elevation tadpoles (Fig. 6I, J, M, N ). In preservation: dorsal body and tail with brown pigmentation; lateral body brown, skin coloration lighter below spiracular tube, with clear white patches; lateral tail muscle brown mottled with dense tiny white dots; upper and lower fin semitransparent brown, lower fin colored lighter; no dark patches on lateral and dorsal tail; ventral body semitransparent white, stained with light brown pigments; lips semitransparent white, papillae brown. When alive, dorsal body and tail basically deep brown, mottled with copper pigmentation, especially dense on body; lateral body brown, with cream-white patches near abdomen; lateral tail brown, scattered with tiny white pigment spots, no dark brown patches on tail; ventral surface of body semitransparent brown, covered with small white pigments; iris brown.

Bioacoustics.

(Fig. 4A, D, G, J ; Suppl. material 1: Tables 4 ; Suppl. material 2: Fig. S3). A total of 16 call groups and 62 calls were analyzed. Average dominant frequency of calls low, 2.5 kHz (2.3-3.0 kHz); call repetition rate moderate, average 1.2 calls per seconds; call interval short, average 153-254 ms; call groups with average 10.8 calls; call duration long (average 746 ms), and with lots of notes (average 42.1). To the human ear, the call sound like "ga ga ga...".

Distribution and natural history.

The species is currently known with certainty from the type locality in Medog County, and its distribution elevation was recorded between 680-2200 m ( Fei et al. 1983, 2012, Fei and Ye, 2016; this study). This species was recorded in or near small mountain streams of tropical rain forests, sit on rocks, leaf litter, and sometimes bare soil. Calls heard between 11 June to 5 August (this study; Fei et al. 2019). Four in five females recorded during 11 June to 18 June were gravid. Males start calling before dusk under dense vegetation. Normally, two or more males call in small groups along stream banks, spacing themselves ca. 3-5 meters from each other. Sequenced tadpoles in metamorphosis were recorded on 18 June, in small mountain stream pond at 1560 m. Tadpoles of two other species of Megophrys share the same ponds. See description in following. Breeding season is supposed to including early June and may last to early August.

Comparison.

Refer to Mahony et al. (2018) for comparison with other species of M. major group. M. medogensis differs from M. pachyproctus by much larger body size (SVL 57.2-68.7 in 21 males vs. 35.3-35.7 in two males in the latter), absence of large protuberance above vent (vs. present in the latter), skin relatively smooth (vs. rough in the latter), frontoparietal distinctly wider in front than rear (vs. almost equally wide in the latter), sagittal suture occlusive (vs. distinctly open in the latter), and columella auris long (vs. short in the latter). For comparisons with species studied in this paper, refer to relevant morphological comparison sections for those species.

Figures

Figure 3. Photos of specimens of Megophrys species in Medog. A-E dorsal views of adult male holotype NWIPB 770650 of M. pachyproctus, adult male topotype CIB 022017061406 of M. medogensis, adult male CIB 022017061805 of M. cf. pachyproctus, adult male holotype CIBMT 171053 of Megophrys zhoui sp. nov., and adult male holotype CIB 201706 MT 02 of Megophrys yeae sp. nov., respectively F-J ventral views of the specimens, respectively K-O lateral view of head of the specimens, respectively P-T ventral view of hand of the specimens, respectively U-Y ventral view of foot of the specimens, respectively. Scale bar for body view equal to 10 mm, and for partial view 5 mm.

Figure 4. Visualization of advertisement calls of three Megophrys species from Medog. A-C visualizations of 60 seconds waveform of relative amplitude over time for M. medogensis (one unvouchered individual recorded in the vicinity of Medog urban area), M. cf. pachyproctus (CIB 022017061807), and Megophrys yeae sp. nov. (paratype CIB 022017061804), respectively D-F visualizations of 20 seconds waveform of relative amplitude over time G-I visualizations of two seconds waveform of relative amplitude for the species, respectively J-L visualizations of two seconds waveform of spectrogram for the species, respectively.

Figure 5. Skull of Megophrys species in Medog. A-E dorsal views of adult male holotype NWIPB 770650 of M. pachyproctus, adult male topotype CIB 022017061406 of M. medogensis, adult male CIB 022017061805 of M. cf. pachyproctus, adult male holotype CIBMT 171053 of Megophrys zhoui sp. nov., and adult male holotype CIB 201706 MT 02 of Megophrys yeae sp. nov., respectively F-J ventral views of the specimens, respectively. Key to skull: 1 premaxillary; 2 maxillary; 3 nasal; 4 sphenethmoid; 5 anterior fontanelle; 6 frontoparietal; 7 sagittal suture; 8 pterygoid; 9 squamosal; 10 quadratojugal; 11 prootic; 12 exoccipital; 13 vomerine ridge; 14 mandible; 15 anterior process of parasphenoid; 16 columella auris. Scale bar equal to 5 mm.

Figure 6. Tadpole specimens of four groups of three Megophrys species from Medog. A-D dorsal views of the low-middle-elevation tadpole CIBMT 20170621 of M. medogensis (Goser stage 35), the high-elevation tadpole CIBMT 171001 of M. medogensis (stage 27), tadpole CIBMT 20170611 of M. cf. pachyproctus (stage 25), tadpole CIBMT 170604 of Megophrys yeae sp. nov. (stage 35), respectively E-H lateral views of the tadpoles, respectively I - L ventral views of the tadpoles, respectively. M-P dorsal views of head of the tadpoles, respectively. Scale bar for body view equal to 10 mm, and for head view 2 mm.

Figure 10. Microhabitats of Megophrys toads in the field in Medog. A stream at elevation 850 m in Didong village, harboring the low-middle-elevation M. medogensis and Megophrys yeae sp. nov. B a stream at 1530 m in Gelin village, hosting the low-middle-elevation M. medogensis and M. pachyproctus C a stream at 1780 m in Bari village, harboring low-middle-elevation M. medogensis, M. cf. pachyproctus and Megophrys yeae sp. nov. D a stream at 2003 m in the vicinity of Renqingbeng Temple, hosting M. cf. pachyproctus and Megophrys zhoui sp. nov. E a stream at 2142 m in Gedang village, hosting M. medogensis F one adult male of low-middle-elevation M. medogensis calling on a dead leaf on the tropical forest ground nearby a stream in Didong village G the adult male paratype CIB 022017061102 of Megophrys yeae sp. nov. calling on a leaf of dense bushes under tropical forest, ca. 0.5 m above a stream in Didong village H the adult male CIB 022017061806 of M. cf. pachyproctus calling on a branch of dead bush, ca. 0.5 m above ground under subtropical forest in Bari village I the gravid female CIBMT 171054 of M. cf. pachyproctus precariously climbing up onto a stem of herb, ca. 0.3 m above a tiny stream under subtropical forest in Renqingbeng J the adult male holotype CIBMT 171053 of Megophrys zhoui sp. nov. sitting on a split of a fern leaf in a small stream under subtropical forest in the vicinity of Renqingbeng Temple.