Quasipaa taoi, Pham & Hoang & Phan & Nguyen & Ziegler, 2022

Pham, Cuong The, Hoang, Chung Van, Phan, Tien Quang, Nguyen, Truong Quang & Ziegler, Thomas, 2022, Hidden in the jungle of Vietnam: a new species of Quasipaa (Amphibia, Anura, Dicroglossidae) from Ngoc Linh Mountain, ZooKeys 1124, pp. 23-42 : 23

Quasipaa taoi sp. nov.

Figs 2 , 3 , 4

Holotype.

IEBR A.4997, adult male, collected by T. Q. Phan and T. D. Tran on 6 March 2019 (15°05'23.3"N, 107°51'17.5"E, at an elevation of 1,560 m asl.) in the evergreen forest of Ngoc Linh Natural Reserve, Xop Commune, Dak Glei District, Kon Tum Province, Vietnam.

Paratypes.

IEBR A.4998, adult male; IEBR A.4999, adult male; IEBR A.5000, adult female; IEBR A.5037, adult female; IEBR A.5038, adult female, the same data as the holotype.

Diagnosis.

Both morphological characters (body very stout, skin rough with dermal ridges and tubercles, forelimbs of males strongly enlarged, with inner side of arms or fingers or chest and belly with black spines (see Fei et al. 2009) and molecular data revealed the new species to be nested within Quasipaa . Quasipaa taoi sp. nov. is distinguishable from its congeners by a combination of the following morphological characters: (1) SVL 79.6-84.3 mm in males, 64.6-69.9 mm in females; (2) head broader than long (HL/HW 0.90 in males, 0.92 in females); (3) vomerine teeth present; (4) external vocal sacs absent; (5) tympanum slightly visible; (6) dorsum with lines of thick ridges and small round tubercles; (7) flanks covered by oval and round tubercles; (8) supratympanic fold present; (9) dorsolateral fold absent; (10) ventrolateral sides, ventral surface of arms, and all fingers with spines in males; (11) the absence of spines on chest and belly in males; (12) toes fully webbed to distal end of terminal phalanx; (13) in life, dorsum dark brown, chest and belly immaculate white.

Description of holotype.

A large frog (SVL 84.3 mm); habitus robust with enlarged head (HL/SVL 0.40, HW/SVL 0.43); head broader than long (HL 33.5 mm, HW 36.3 mm); snout round anteriorly in dorsal view, projecting beyond lower jaw; nostril lateral, closer to eye than to the tip of snout (NS 7.6 mm, EN 5.5 mm); canthus rostralis indistinct; loreal region oblique and slightly concave; rostral length greater than eye diameter (RL 13.1 mm, ED 9.7 mm); internarial distance wider than interorbital distance and upper eyelid width (IND 8.6 mm, IOD 6.2 mm, UEW 7.7 mm); tympanum slightly visible (TYD 4.1 mm) smaller than the distance from tympanum to eye (TYE 4.9 mm); vomerine teeth in two oblique ridges; tongue cordiform, notched posteriorly; external vocal sac absent.

Forelimbs: arms short; upper arm length (UAL) 17.1 mm, forearm length (FAL) 41.5 mm; relative finger lengths: II<I<IV<III; fingers free of webbing; dermal ridge on sides of fingers present on fingers I, II, III; tips of fingers swollen, not expanded; subarticular tubercles prominent, round, formula 1, 1, 2, 2; inner metatarsal tubercle round; outer metatarsal tubercle elongate; finger I with nuptial pad.

Hindlimbs: tibia length longer than thigh length (FeL 44.2 mm, TbL 49.7 mm), approximately 3.4 times longer than wide (TbW 14.5 mm); tips of toes swollen, slightly round; relative length of toes: I<II<V<III<IV; toes fully webbed to distal end of terminal phalanx; dermal ridge present on outer sides of toes I and V; subarticular tubercles prominent, elongate, formula 1, 1, 2, 3, 2; inner metatarsal tubercle elongate; outer metatarsal tubercle absent; tibio-tarsal articulation reaching to tip of snout.

Skin texture in life: dorsal surface of head with oval and round tubercles, dorsum with six lines of thick ridges intermixed with small round tubercles; flanks covered by oval and round tubercles; supratympanic fold distinct, extending from eye to angle of jaw; dorsolateral fold absent; dorsal surface of forelimbs and hindlimbs with small tubercles; belly and ventral surface of thighs smooth.

Nuptial spines: body of males with spines except for chest, belly, and ventral surface of hindlimbs; dense spines on dorsum, flanks, ventral surface of forelimbs, ventrolateral sides, and fingers I, II; spines present on throat, dorsal surface of fore- and hindlimbs, and fingers III, IV, small and scattered.

Coloration in life: iris dark copper; dorsum and upper part of flanks dark brown; lower part of flanks whitish brown with white tubercles and black spines on top; supratympanic fold dark brown; dorsal surface of limbs yellowish brown with dark crossbars; ventral surface of limbs light yellow with brown markings; throat white with brown markings; chest and belly immaculate white; toe webbing dark brown.

Coloration in preservative: coloration in preservative is the same in life but somewhat faded.

Sexual dimorphism.

Measurements and morphological characters of the type series are provided in Table 3 . Males are larger than females (SVL 82.7 ± 2.69 mm, n = 3 males vs 67.6 ± 2.7 mm, n = 3 females). The male specimens have a nuptial pad on finger I and dark spines on flanks, ventral surface of forelimbs, ventrolateral sides, and all fingers. The females contained yellowish-cream eggs of varying sizes.

Etymology.

The new species is named in honor of our colleague and friend, Assoc. Prof. Dr. Tao Thien Nguyen from the Institute of Genome Research, Vietnam Academy of Science and Technology, in recognition of his numerous scientific contributions towards a better understanding of the amphibians of Vietnam. We recommend “Tao’s Spiny Frog" as the common English name of the new species and the common name in Vietnamese as "Ếch gai sần t ạo”.

Ecological notes.

Specimens were found between 19:00 and 23:00 in the headwaters of rocky streams (Fig. 5B ). They were found in the water or on the ground of stream banks at an elevation of above 1,500 m a.s.l. The surrounding habitat was secondary forest of large, medium-sized, and small hardwoods mixed with shrubs and vines (Fig. 5A ). Air temperatures at the sites ranged from 18.5-22.5 °C and relative humidity was 68-85%. Male advertisement calls and tadpoles of the species have not been recorded during our field surveys. Other amphibian species found at the sites included Leptobrachella sp., Limnonectes kiziriani Pham, Le, Ngo, Ziegler & Nguyen, 2018, L. poilani (Bourret, 1942), Amolops spinapectoralis Inger, Orlov & Darevsky, 1999, Odorrana khalam (Stuart, Orlov & Chan-ard, 2005), O. morafkai (Bain, Lathrop, Murphy, Orlov & Ho, 2003), Kurixalus cf. banaensis (Bourret, 1939), and Rhacophorus annamensis (Smith, 1924).

Distribution.

Quasipaa taoi sp. nov. is currently known from Ngoc Linh Mountain of the Central Highlands in Vietnam (Fig. 6 ). Data obtained from GenBank show that this species was also recorded from Xekong Province, Lao PDR ( Yan et al. 2021; see Discussion below).

Comparisons.

We compared the new species with its congeners. Quasipaa taoi sp. nov. differs from Q. boulengeri by having a smaller size, SVL 79.6-84.3 mm, n = 3 in males, 64.6-69.9 mm, n = 3 in females (vs 87.8-101.7 mm, n = 6 in males, 82.5-105.5 mm, n = 5 in females), dorsum with thick ridges and round tubercles (vs elongate ridges), males with nuptial spines on all fingers (vs absent on finger IV); males with nuptial spines on throat and ventral surface of arms (vs absent), and the absence of nuptial spines on chest and belly in males (vs present). In the PCA analysis, the first two principal component axes could separate Quasipaa taoi sp. nov. from Q. boulengeri by 24 characters (Fig. 7 ), mainly based on limb and head measurements, namely: SVL, HW, HL, MN, MFE, MBE, RL, ED, UEW, IND, IOD, DAE, DPE, NS, EN, TD, TYE, UAL, FAL, FeL, TbL, TbW, FoL, and IMT (Tables 3 , 4 ). In males, the PCA extracted three principal component axes with eigenvalues greater than 0.002 and, of these, the first two component axes accounted for 85.50% of the variation (Table 4 ). Species with a larger and positive score on PC1 reflected shorter SVL including all traits. The PC2 with positive scores were associated with species having greater measurements of RL, ED, UEW, IND, IOD, DAE, DPE, NS, EN, TYE, UAL, FeL, TbL, and FoL, while negative scores with species having smaller measurements of SVL, HW, HL, MN, MFE, MBE, TD, FAL, TbW, and IMT (Table 4 ). In females, the PCA extracted three principal component axes with eigenvalues greater than 0.01 and of these, the first two component axes accounted for 85.98% of the variation (Table 4 ). Species with a higher and positive score on PC1 reflected having shorter measurements of SVL, HW, HL, MN, MFE, MBE, RL, ED, UEW, IND, IOD, DAE, NS, EN, TD, TYE, UAL, FAL, FeL, TbL, TbW, FoL, and IMT, while a negative score with species having smaller DPE. The PC2 with positive scores were associated with species having greater measurements of SVL, HW, HL, MN, MFE, MBE, RL, ED, IOD, DAE, DPE, NS, EN, TD, TYE, UAL, FAL, FeL, TbL, TbW, and FoL, while a negative score with species having smaller measurements of UEW, IND, and IMT (Table 4 ). Quasipaa taoi sp. nov. differs from Q. acanthophora by having the dorsum with thick ridges and round tubercles (vs small tubercles), males with nuptial spines on ventrolateral sides and ventral surface of arms (vs absent), males with nuptial spines on all fingers (vs absent on finger IV), and the absence of spines on chest of males (vs present). Quasipaa taoi sp. nov. differs from Q. courtoisi by having a smaller size in males, SVL 79.6-84.3 mm, n = 3 (vs 126 mm, n = 1); males with nuptial spines on throat and ventral surface of arms (vs absent); and the absence of nuptial spines on chest in males (vs present). Quasipaa taoi sp. nov. differs from Q. delacouri by having a smaller size, SVL 79.6-84.3 mm, n = 3, in males and 64.6-69.9 mm, n = 3, in females (vs 92.9-115.5 mm, n = 4, in males and 94.5-117.5 mm, n = 3, in females); a greater ratio of TD/ED, 0.44 ± 0.02, n = 3, in males and 0.49 ± 0.01, n = 3, in females (vs 0.26 in males and 0.24 in females); dorsum with thick ridges and round tubercles (vs smooth); males with nuptial pad on finger I (vs absent in males); and males with nuptial spines (vs absent). The new species differs from Q. exilispinosa by having a larger size in males (SVL 79.6-84.3 mm, n = 3, in males and 64.6-69.9 mm, n = 3, in females (vs 61.2 mm, n = 20, in males and 57.1 mm, n = 20, in females); dorsum with thick ridges and round tubercles (vs small tubercles); males with nuptial spines on ventrolateral sides and ventral surface of arms (vs absent); males with nuptial spines on all fingers (vs absent on finger IV); and absence of spines on chest in males (vs present). Quasipaa taoi sp. nov. differs from Q. fasciculispina by having a smaller size, SVL 79.6-84.3 mm, n = 3 in males and 64.6-69.9 mm, n = 3 in females (vs 106 mm, n = 1 in males and 104 mm, n = 1 in females); a smaller ratio of TYE/TD (1.11 ± 0.16, n = 3, in males and 1.2 ± 0.16, n = 3, in females (vs 2.0 in male and 1.75 in female); the absence of nuptial spines on chest in males (vs circular whitish tubercles each bearing 5-10 strong black spines). Quasipaa taoi sp. nov. differs from Q. jiulongensis by having dorsum with thick ridges and round tubercles (vs small tubercles), males with nuptial spines on ventrolateral sides and ventral surface of arms of males (vs absent), males with nuptial spines on all fingers (vs absent on fingers III and IV); the absence of light-colored longitudinal stripes on upper jaw edge (vs present); and the absence of 4 or 5 yellow dorsal dots arranged in longitudinal rows (vs present). Quasipaa taoi sp. nov. differs from Q. robertingeri by having dorsum with thick ridges and round tubercles (vs elongate ridges), males with nuptial spines on all fingers (vs absent on finger IV); males with nuptial spines on throat and ventral surface of arms (vs absent), and the absence of nuptial spines on chest and belly of males (vs present). Quasipaa taoi sp. nov. differs from Q. shini by its smaller size, SVL 79.6-84.3 mm, n = 3, in males and 64.6-69.9 mm, n = 3, in females (vs 98.6 mm, n = 9, in males and 94.9 mm, n = 10, in females); dorsum with thick ridges and round tubercles (vs elongate ridges), males with nuptial spines on all fingers (vs absent on finger IV); males with nuptial spines on throat and ventral surface of arms (vs absent), and the absence of nuptial spines on chest and belly of males (vs present). Quasipaa taoi sp. nov. differs from Q. spinosa by its smaller size, SVL 79.6-84.3 mm, n = 3, in males and 64.6-69.9 mm, n = 3, in females (vs 106.0-142.0 mm, n = 20, in males and 115.0-152.5 mm, n = 10, in females); dorsum with short, thick ridges and round tubercles (vs small tubercles); the absence of light colored longitudinal stripes on upper jaw edge (vs present); and the absence of nuptial spines on chest of males (vs small and dense spines on chest of males). Quasipaa taoi sp. nov. differs from Q. verrucospinosa by its smaller size (SVL 79.6-84.3 mm, n = 3, in males and 64.6-69.9 mm, n = 3, in females (vs 90.0-117.0, n = 8, in males, 83.2-113.9 mm, n = 9, in females); males with nuptial spines on all fingers (vs absent on fingers III and IV); males with nuptial spines on ventral surface of arms (vs absent), and the absence of nuptial spines on chest and belly in males (vs present). Quasipaa taoi sp. nov. differs from Q. yei by its larger size in males (SVL 79.6-84.3 mm, n = 3, in males and 64.6-69.9 mm, n = 3, in females (vs 49.7-64.0 mm, n = 25); males with nuptial spines on ventrolateral sides and ventral surface of arms (vs absent); and males with nuptial spines on all fingers (vs absent); absence of nuptial spines around and inside vent (vs present).

Figures

Figure 2. Quasipaa taoi sp. nov., holotype (IEBR A. 4997, male) in life A dorsolateral view B ventral view.

Figure 3. Quasipaa taoi sp. nov., holotype (IEBR A. 4997, male) in preservative A dorsolateral view B ventral view.

Figure 4. Quasipaa taoi sp. nov., holotype (IEBR A. 4997, male) A upper right hand B lower right hand C lower right foot.

Figure 5. Habitat of Quasipaa taoi sp. nov. in Ngoc Linh Nature Reserve, Kon Tum Province, Viet Nam A evergreen forest B microhabitat.

Figure 6. Map showing the type locality (circle) of Quasipaa taoi sp. nov. in Kon Tum Province, Vietnam.

Figure 7. Plots of the first principal component (PC 1) versus the second (PC 2) for the males and the females of Quasipaa taoi sp. nov. (red +) and Q. boulengeri (blue □).