Thursday, March 18, 2021

[Herpetology • 2021] Cyrtodactylus raglai • A New Granite Cave-dwelling Bent-toed Gecko from Vietnam of the Cyrtodactylus irregularis Group (Squamata; Gekkonidae) and A Discussion on Cave Ecomorphology


 Cyrtodactylus raglai
 Nguyen, Duong, Grismer & Poyarkov, 2021

 Photographs by Anh The Nguyen.

Abstract
An integrative analysis of genetic, morphological, and ecological data recovered a new granite cave-adapted species, Cyrtodactylus raglai sp. nov., from the Song Giang River Valley, Khanh Hoa Province, Vietnam. Cyrtodactylus raglai sp. nov. is nested within one of two major clades within the irregularis species group where it forms a monophyletic group with C. cryptus and its sister species C. kingsadai. It differs from its sister species by an uncorrected pairwise sequence divergence of 16.5% and 16.8% based on the mitochondrial genes NADH dehydrogenase subunit 2 and its flanking tRNAs and the first subunit of cytochrome oxidase c (CO1), respectively. Cyrtodactylus raglai sp. nov. is a narrow-range endemic restricted to a riparian, granite cave microhabitat and its overall morphology bears that of other granite cave-dwelling ecomorphs in the genus. The Song Giang River Valley and its associated waterways are currently threatened by the construction of a hydropower station which will negatively impact the surrounding ecosystem. Urgent field surveys in this region are necessary in order to obtain critical data on its biodiversity and importance to conservation efforts in southern Vietnam.

Key words: Ecomorph, Indochina, narrow-range endemic, reptiles, taxonomy

Figure 6. Adult male holotype of Cyrtodactylus raglai sp. nov. (SIEZC 2.0244).
A. Dorsal view. B. Ventral view of thighs and precloacal region. C. Right lateral view of head. D. Ventral view of gular region. E. Ventral view of left foot. F. Ventral view of left hand.
Photographs by Anh The Nguyen.

Figure 7. Type series of Cyrtodactylus raglai sp. nov.
 A. Adult male holotype SIEZC 2.0244. B. Adult female paratype SIEZC 2.0243. C. Adult female paratype ZMMU R16688.
 Photographs by Anh The Nguyen.

Cyrtodactylus raglai sp. nov. 
Suggested Common Name: Raglai Bent-toed Gecko; 
 
Diagnosis: Cyrtodactylus raglai sp. nov. can be separated from all other species of clade1 of the C. irregularis group by having 10 or 11 supralabials; nine or 10 infralabials; 44–47 paravertebral tubercles; 14 or 15 rows of longitudinally arranged tubercles; 36–39 ventrals; 8–10 expanded subdigital lamellae, 12 or 13 unexpanded subdigital lamellae, and 21–22 total subdigital lamellae on the fourth toe; 18 or 19 enlarged femorals; 12 enlarged precloacals; four rows of enlarged post-precloacals; three postcloacal tubercles in males; five precloacal pores in the male; no pitted precloacal scales in females; enlarged femorals and enlarged precloacals not continuous; proximal femorals less than one-half size of distal femorals; enlarged subcaudals; maximum SVL 111.7 mm; small, irregularly shaped dark blotches on top of head; and four irregularly shaped body bands edged with white tubercles wider than the interspaces (Tables 5, 6).

Distribution: (Fig. 1). Cyrtodactylus raglai sp. nov. is known only from the type locality in the Song Giang River valley, Khanh Trung Commune, Khanh Vinh District, Khanh Hoa Province, Vietnam.

Etymology: The new species name “raglai” is given in a reference to the Raglai people, an ethnic group living in the forested mountain areas of Khanh Hoa Province of Vietnam, including the Song Giang River Valley where the new species was found. In Raglai language, the self-designating word “raglai” also means “forest”, stressing the importance of the tropical forest ecosystem for this people. To reflect this polysemy, the new species name is given as a noun in apposition and hence is invariable.
 
Figure 8. Habitat (A) and granite cave microhabitat (B and C) of Cyrtodactylus raglai sp. nov. at the type locality.
Photographs by Anh The Nguyen.


Figure 9. General morphology of the six species of cave ecomorphs in the genus Cyrtodactylus from Vietnam.
A. Cyrtodactylus raglai sp. nov. from the Song Giang River Valley, Khanh Hoa Province. B. C. hontreensis from Hon Tre Island, Kien Giang Province.
C. C. grismeri from Tuc Dup Hill, An Giang Province. D. C. badenensis from Ba Den Mountain, Tay Ninh Province.
E. C. nigriocularis from Ba Den Mountain, Tay Ninh Province. F. C. eisenmanae from Hon Son Island, Kien Giang Province. 

Photograph by Anh The Nguyen (A), L. Lee Grismer (B-C),  Nikolay A. Poyarkov (D-E), Ngo Van Tri (F). 

Figure 1. Distribution of the species of the Cyrtodactylus irregularis group. Dot in the center of an icon indicates the type locality of a species. The small inset map shows Vietnam and the location of the area of studies detailed in a larger map (red rectangle). For details on species localities see Pauwels et al. (2018); Neang et al. (2020); and Ostrowski et al. (2020).

    


 Anh The Nguyen, Tang Van Duong, L. Lee Grismer and Nikolay A. Poyarkov. 2021. A New Granite Cave-dwelling Bent-toed Gecko from Vietnam of the Cyrtodactylus irregularis Group (Squamata; Gekkonidae) and A Discussion on Cave Ecomorphology.  Vertebrate Zoology. 71: 155-174. DOI: 10.3897/vz.71.e60225