Amolops shihaitaoi, Wang & Li & Du & Hou & Yu, 2022

Wang, Jian, Li, Jing, Du, Lingyun, Hou, Mian & Yu, Guohua, 2022, A cryptic species of the Amolops ricketti species group (Anura, Ranidae) from China-Vietnam border regions, ZooKeys 1112, pp. 139-159 : 139

Amolops shihaitaoi sp. nov.

Figs 4 , 5 , 6 , 7

Chresonymy.

Amolops ricketti in Yang (1991), Inger et al. (1999), Ngo et al. (2006), Yang and Rao (2008), Nguyen et al. (2009), Stuart et al. (2010), Grosjean et al. (2015); Amolops yatseni in Wu et al. (2020); Amolops tonkinensis in Poyarkov et al. (2021).

Holotype.

GXNU YU000353 (Figs 4 , 5 ), adult female, collected on 21 June 2020 by Jian Wang from Hekou, Yunnan, China (22.6287°N, 103.8776°E; 532 m a.s.l.).

Paratypes.

Six adult females (GXNU YU000351, GXNU YU000352, GXNU YU000354, GXNU YU000355, GXNU YU000478, and GXNU YU000479) and two adult males (GXNU YU000482 and GXNU YU000483) with same collection information as holotype.

Etymology.

Specific epithet shihaitaoi is named after Prof. Hai-Tao Shi from Hainan Normal University for his outstanding contribution to the herpetology of China. We suggest the common English name "Hekou torrent frog" and Chinese name “Hé Kǒu Tuān Wā ( 河口湍蛙)”.

Diagnosis.

The new species is assigned to genus Amolops and further to the A. ricketti group morphologically based on the absence of dorsolateral folds, presence of circummarginal groove on disc of the first finger, disc of first finger distinctly smaller than that of second finger, absence of tarsal fold and tarsal glands, and presence of nuptial pads with conical nuptial spines on the first finger in breeding male.

Amolops shihaitaoi sp. nov. can be distinguished from other members of A. ricketti group by having a combination of the following characters: body size moderate (SVL 35.5-37.3 mm in males and 39.2-45.7 mm in females); white spines on temporal region, loreal region, snout, and lips present in breeding males but absent in females (Fig. 5 ); presence of small, dense, translucent or white spines on the dorsal skin of the body, dorsal and dorsolateral skin of limbs; heels overlapping; tibiotarsal articulation reaching tip of snout; longitudinal glandular folds on the skin of shoulders indistinct; presence of supernumerary tubercles below the base of fingers II-IV, pineal body distinct; presence of vomerine teeth; and absence of vocal sacs.

Description of holotype.

Adult female (SVL 43.8 mm; Table 3 ); head width (HW 15.2 mm) greater than head length (HL 13.6 mm; HW/HL = 1.12); snout short and rounded in profile, projecting beyond margin of lower jaw in ventral view; canthus rostralis distinct; loreal region sloping, concave; nostrils oval, lateral; internarial distance (IND 5.5 mm) greater than interorbital distance (IOD 3.3 mm; IND/IOD = 1.67); upper eyelid width (UEW 4.3 mm) greater than interorbital space (UEW/IOD = 1.30); pineal spot present; pupil oval, horizontal; tympanum small (TD 1.5 mm), rounded, less than half eye diameter (ED 5.9 mm; TD/ED = 0.25); supratympanic fold distinct, start from posterior edge of eye and extending to should; vomerine teeth in two oblique rows between choanae; choanae oval; tongue cordiform, deeply notched posteriorly.

Forelimbs moderately robust; relative length of fingers I<II<IV<III; all fingertips expanded into discs with circummarginal grooves, relative width of finger disks I<II<III=IV; webbing between fingers absent; subarticular tubercles prominent and rounded, formula 1, 1, 2, 2; supernumerary tubercle present and prominent below the base of fingers II-IV; two metacarpal tubercles.

Hindlimbs long and robust, tibiotarsal articulation reaching tip of snout when hindlimb stretched alongside of body; heels slightly overlapping when legs positioned at right angles to body; tarsal glands absent; relative length of toes I<II<III=V<IV; all toe tips expanded into discs with circummarginal grooves; toes fully webbed, webbing formula I1-1II1-1III1-1IV1-1V; lateral fringes of toes I and V developed; subarticular tubercles prominent and rounded, formula 1, 1, 2, 3, 2; inner metatarsal tubercle prominent; outer metatarsal tubercle absent.

Dorsolateral fold absent; dorsal surface rough and granular with denser small translucent or white warts on dorsal body and dorsal limbs; flanks very rough and granular, scattered with large raised white tubercles; rictal gland prominent; large white and small translucent warts present around the vent; skin of throat, chest, and venter slightly wrinkled, both sides of venter obviously granular; ventral surface of limbs smooth.

Coloration in life.

Dorsal surface of olive-brown with dark brown patches on dorsal surface of head and trunk and dark brown irregular transverse bars on dorsal surface of limbs; dorsal surface of discs white-mottled with cropper on discs of fingers III and IV and all toe discs; region around cloaca olive-brown with rusty mottling on both sides; sides of head olive-brown with dark brown blotches; rictal gland light yellow; flanks olive-brown, warts on flanks dark or white; throat and chest creamy white scattered with distinct dark blotches and mottled with light yellow; belly creamy white mottled with light yellow; ventral surface of limbs semi-opaque, grey, mottled with light yellow; webbing between toes beige, mottled with black; iris black with brown mottling (Fig. 4 ).

Coloration in preservative.

Dorsal surface dark brown, with irregular light patches; dark brown transverse bars on limbs distinct; ventral surface grayish white, with dark mottling on throat and chest (Fig. 5 ).

Morphological variation.

The new species is sexually dimorphic. Males are smaller than females (Table 1 ) and possess nuptial pads with spines in the breeding season (Fig. 6 ). Additionally, spines on dorsal skin in males are less distinct than in females. A male specimen in breeding season (GXNU YU000483) has distinct spines on the temporal region, loreal region, snout, lips, and chin, and has conical spines on the nuptial pad, whereas a male specimen in the early stage of development (GXNU YU000482) lacks distinct spines on the temporal region, loreal region, snout, lips, and chin and its nuptial spines are papillate (Fig. 6 ). All types have no beige snowflake-like patches on the ventral surface of limbs with the exception of GXNU YU000482. In addition, the three types (GXNU YU000352, GXNU YU000353, GXNU YU000355, and GXNU YU000479) nearly have no light yellow coloration of on the undersides of the limbs. Compared to other types, GXNU YU000482 has less distinct dark patches on the throat and chest (Fig. 7 ).

Distribution.

In addition to the type locality in Hekou, Yunnan, China, the new species also occurs in Jingxi, Guangxi, China and northern Vietnam (Vĩnh Phúc, Cao Bằng, and Lào Cai) because our molecular analyses revealed that samples from Jingxi, Vĩnh Phúc, Cao Bằng, and Lào Cai that were sequenced by previous studies also belong to the new species. In Yunnan, the new species inhabits rocky streams (Fig. 8 ). Much of the ecology and behavior of this species remains unknown.

Comparisons.

The absence of dorsolateral folds, presence of circummarginal groove on disc of the first finger, disc of first finger distinctly smaller than that of second finger, absence of tarsal fold and tarsal glands, and presence of nuptial pads with conical nuptial spines on the first finger in breeding males suggest that the new species belongs to the A. ricketti species group, which is supported by the molecular evidence (Fig. 2 ). Morphological comparisons among the members of the A. ricketti species group are summarized in Table 4 . Amolops shihaitaoi sp. nov. is recovered as the sister taxon to A. yatseni , but morphologically it differs from the later by the absence of white spines on temporal region and lower lips in female (vs present; Fig. 9 ), supernumerary tubercles moderate developed (vs very distinct; Fig. 9 ), and heels overlapping (vs just meeting).

The new species has been previously reported as A. ricketti , but it can be distinguished from the later by smaller body size (39.2-45.7 mm vs 53.5-67.0 mm in females), presence of dense small translucent or white spines on the dorsal skin of the body, dorsal and dorsolateral skin of limbs (vs absent), presence of spines on skin of temporal region, loreal region, and lips in breeding males (vs absent), and tibiotarsal articulation reaching tip of snout (vs reaching eyes). Amolops shihaitaoi sp. nov. differs from A. sinensis by relatively smaller body size (SVL 39.2-45.7 mm vs 47.7-52.7 mm in females), presence of small, dense, translucent or white spines on the dorsal skin of the body, dorsal and dorsolateral skin of limbs (vs absent), presence of supernumerary tubercles below the base of finger II (vs absent), and longitudinal glandular folds on the skin of shoulders indistinct (vs distinct); from A. albispinus by the presence of dense translucent or white spines on the dorsal skin of the body, dorsal and dorsolateral skin of the limbs (vs absent), ventral surface relatively smooth (vs with numerous small tubercles and ridges on the throat and ventral surfaces of trunk and limbs), and pineal body distinct (vs indistinct); and from A. wuyiensis and A. yunkaiensis by the presence of vomerine teeth (vs absent) and absence of vocal sacs (vs present). The new species further obviously differs A. wuyiensis by nuptial spines beige (vs black).

Figures

Figure 2. Bayesian phylogram of the Amolops ricketti species group inferred from the combined data of 16 S and COI genes with inclusion of all individuals (A) and inclusion of only individuals for which both the two genes are available (B).

Figure 4. Views of the holotype of Amolops shihaitaoi sp. nov. (GXNU YU 000353) in life.

Figure 5. Holotype of Amolops shihaitaoi sp. nov. (GXNU YU 000353) in preservative A dorsal view B ventral view.

Figure 6. Two male paratypes of Amolops shihaitaoi sp. nov. A GNXU YU 000483 B GXNU YU 000482.

Figure 7. Ventral view of paratypes of Amolops shihaitaoi sp. nov. in life.

Figure 8. Habitat of Amolops shihaitaoi sp. nov. at the type locality.

Figure 9. A, B Amolops shihaitaoi sp. nov. A head of female holotype GXNU YU 000353 B hand of male paratype GXNU YU 000483 C, D A. yatseni (reproduced from Lyu et al. 2019) C head of female paratype SYS a 003981 D hand of male holotype SYS a 006807.