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| (K, L) the holotype of Microhyla daklakensis sp. nov. (male); (M) the paratype of Microhyla ninhthuanensis sp. nov. (female); (I, J) Microhyla ‘heymonsi’ (male) Hoang, Nguyen, Ninh, Luong, ... et Jiang, 2021 Photographs by C.V. Hoang and N.L. Orlov. |
Abstract
The Microhyla heymonsi species complex from central Vietnam was examined, and based upon morphological and molecular evidence, two new species are described. The discovery of Microhyla daklakensis sp. nov. and Microhyla ninhthuanensis sp. nov. brings the total number of known species in the genus to 46 and the species number of Microhyla in Vietnam to 13. The Truong Son Range harbors the highest diversity of the genus Microhyla with 11 recorded species so far. However, this apparent micro-endemic diversity is at risk because of habitat loss by deforestation, which highlights the necessity of further research leading to improved conservation measures.
Keywords: Microhyla, new species, central Vietnam, morphology, molecular phylogeny
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| Dorsolateral and ventral views of the specimens in life: Dorsolateral and ventral views of the specimens in life: comparative specimen of M. ‘heymonsi’ (KPMĐ2018.42, male) (I, J); the holotype of Microhyla daklakensis sp. nov. (VNMN 06877, male) (K, L); the paratype of Microhyla ninhthuanensis sp. nov. (ZISP 14254 (HAO186), female) (M). Photographs by C.V. Hoang and N.L. Orlov. |
Microhyla ninhthuanensis sp. nov.
Diagnosis: Microhyla ninhthuanensis sp. nov. is distinguished from its congeners by a combination of the following morphological characters: 1) body stocky, size medium (SVL 17.3–18.8 mm, n = 9 males; 21.6–23.6 mm, n = 2 females). 2) dorsum smooth; 3) head triangular, snout round in profile; 4) finger I shorter than one-half the length of finger II; 5) tips of all outer fingers dilated, forming disks, with a median longitudinal groove visible dorsally; 6) tips of all toes distinctly dilated into disks, with a weak median longitudinal groove visible dorsally, producing the appearance of two scutes; 7) inner metacarpal tubercle oval and prominent, paired outer metacarpal tubercle divided by a waist into two equal-sized parts: outer part quite round, inner part quite crescent; 8) tibiotarsal articulation of straightened limb not reaching snout; 9) webbing basal: I2 – 2½II2 – 3III3 – 4IV4⅓ – 3V; 10) inner metatarsal tubercles oval, prominent and outer metatarsal tubercles round; 11) upper eyelid without supraciliary spines; 12) narrow faint brown stripe extending from rear corner of eye to axilla; 13) light thin vertebral stripe present, canthus rostralis with dark lines; 14) small dark round spot at mid-dorsum, divided by a light vertebral stripe; 15) dorsum pinkish brown with dark brown marking in X-shape between eyes and arm, along vertebral and dorsolateral region stripes form wavy dust strip towards the groin, a small dark marking ‘ ()’-shaped in the center of the dorsum and mid-dorsal line; 16) an even black lateral stripe from above arm, almost reaching groin; 17) chin dark grey; throat white with scattered dark grey dusting; chest and belly creamy white.
Etymology: Specific epithet is in reference to the type locality, Ninh Thuan Province. We recommend “Ninh Thuan narrow-mouth frog” as the common English name and “Nhái bầu ninh thuận” as the Vietnamese name.
Natural history: All specimens were collected at night from 19:00 to 23:00 h on the ground near the banks of a small stream in the forest and on the sides of a recently constructed road next to the devastated forests (Fig. 6B). Larval stages and eggs of the new species are unknown.
Distribution: Microhyla ninhthuanensis sp. nov. is currently only known from the type locality in Phuoc Binh National Park, Ninh Thuan Province, Vietnam (Fig. 1). The species was recorded at an elevation of ca. 300 m a.s.l.
Microhyla daklakensis sp. nov.
Diagnosis: (1) Microhyla daklakensis sp. nov. is distinguished from its congeners by a combination of the following morphological characters: 1) body stocky, size medium (SVL 17.7–20.1 mm n = 4 males; 21.1–23.8 mm, n = 6 females), 2) dorsum smooth; 3) snout round in profile; 4) finger I longer than one-half the length of the finger II; 5) tips of all outer fingers dilated, forming disks, with a median longitudinal groove visible dorsally; 6) tips of all toes distinctly dilated into disks, with a weak median longitudinal groove visible dorsally, producing the appearance of two scutes; 7) inner metacarpal tubercle oval and prominent, paired outer metacarpal tubercle divided by a waistline into two equal-sized parts: outer part quite round, inner part crescent-shaped; 8) tibiotarsal articulation of straightened limb not reaching snout; 9) webbing basal: I2 – 2½II2 – 3III3 – 4IV4⅓ – 3V; 10) inner metatarsal tubercles oval, prominent and outer metatarsal tubercles round; 11) upper eyelid without supraciliary spines; 12) narrow faint brown stripe extending from rear corner of eye to axilla; 13) thin, pale vertebral stripe present, canthus rostralis with dark lines; 14) small dark round spot at mid-dorsum, divided by a light vertebral stripe; 15) dorsal surface yellowish brown, a dark brown marking in V-shape between eyes to insertion of arms; 16) vertebral and dorsolateral stripes form wavy dust strip towards the groin; 17) a small dark marking in ‘ ()’-shape on the center of the dorsum and mid-dorsal line; 18) an evenly colored black lateral stripe from above the insertion of the arms, almost reaching groin; 19) chin dark grey; throat white with scattered dark grey dusting; chest and belly creamy white.
Etymology: Specific epithet is in reference to the type locality, Dak Lak Province. We recommend “Dak Lak narrow-mouth frog” as the common English name and “Nhái bầu dak lak” as the Vietnamese name.
Natural history: All specimens were collected at night from 19:00 to 23:00 h on the ground near the banks of small temporary ponds formed after heavy rain, along the edges of the forest and on the sides of a recently constructed road next to the devastated forests (Fig. 6A). The new species was found in sympatry with four congeners including M. berdmorei, M. butleri, M. mukhlesuri, and M. pulchra, all of which were reproducing simultaneously with the new species in the same breeding site. Other anurans such as Fejervarya limnocharis, Occidozyga cf. lima, and Occidozyga martensii also occurred in sympatry. Larval stages and eggs of the new species are unknown.
Distribution: Microhyla daklakensis sp. nov. is currently known only from the type locality in Nam Ka Nature Reserve, Krong No District, Dak Lak Province, Vietnam (Fig. 1). The species was recorded at an elevation of ca. 500 m a.s.l.
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| Figure 1. Map showing the type localities of Microhyla ninhthuanensis sp. nov. in Ninh Thuan Province (2) and Microhyla daklakensis sp. nov. in Dak Lak Province (1) in Tay Nguyen Plateau (Central Highlands) of Vietnam (E.J. Sterling and K Koy kindly provided the map). |
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| Dorsolateral and ventral views of the specimens in life: comparative specimen of Microhyla neglecta (VNMN 07344, male) (A, B); (VNMN 07673, female) (C, D); comparative specimen of M. pineticola (VNMN 07441, female) (E, F) and (VNMN 07455, male) (G, H). Photographs by C.V. Hoang and N.L. Orlov. |
Chung Van Hoang, Tao Thien Nguyen, Hoa Thi Ninh, Anh Mai Luong, Cuong The Pham, Truong Quang Nguyen, Nikolai L. Orlov, Youhua Chen, Bin Wang, Thomas Ziegler and Jianping Jiang. 2021. Two New Cryptic Species of Microhyla Tschudi, 1838 (Amphibia, Anura, Microhylidae) related to the M. heymonsi Group from central Vietnam. ZooKeys. 1036: 47-74. DOI: 10.3897/zookeys.1036.56919
