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| Dibamus irregularis Kliukin, Poyarkov, Bragin, Krone & Nguyen, in Kliukin, Bragin, Nguyen, Vu, Le, Gorin, Krone & Poyarkov, 2026 |
Abstract
A new species of dibamid lizard, Dibamus irregularis sp. nov. is described based on molecular (three mitochondrial genes) and morphological (external and skeletal) characters of twelve specimens collected from the Chu Yang Sin National Park, Dak Lak Province, southern Vietnam. The new species can be distinguished from other congeners by the following combination of characters: medial rostral suture absent or incomplete, nasal sutures incomplete, labial sutures complete or incomplete; two to three postoculars; three to four scales on the posterior edge of infralabial; 22–24 midbody scale rows; 180–211 ventral scales; 39–46 subcaudal scales; and maximum snout-vent length 147 mm. Moreover, two eggs of a new species were collected in the same locality. The only known clutch of Dibamus was described more than 120 years ago based on a single egg of D. alfredi collected from Bukit Besar, Thailand. Herein, we provide the first description of a complete clutch of the genus Dibamus based on two eggs of Dibamus irregularis sp. nov. Our study brings the total number of species in the genus Dibamus to 30; Dibamus irregularis sp. nov. is the 10th species of Dibamus recorded from Vietnam, highlighting the importance of the country as a hot spot of reptilian diversity in Southeast Asia.
Reptilia, Dibamus irregularis sp. nov., Dak Lak Province, conservation, Southeast Asia, systematics, morphology, reproduction
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| Dibamus irregularis sp. nov. in life. (A) holotype ZMMu re-18313, male; (B) Paratype ZMMu re-18315, female. Photographs by Andrey M. Bragin |
Dibamus irregularis sp. nov.
Kliukin, Poyarkov, Bragin, Krone & Nguyen
Etymology. the new species epithet is a latin adjective in nominative singular, meaning “irregular,” andis given in reference to the high intraspecific variability of external morphological features in the new species,especially to the irregularity and asymmetry of the number of postocular scales (Fig. 6). Since Allen greer’s revision(greer 1985) and in all subsequent papers describing new species of Dibamus, the number of postocular scales wasconsidered as a relatively stable diagnostic character underlying diagnoses for new species of dibamids, which in partcould be explained by generally small sample sizes of Dibamus spp. available for examination. however, Dibamus irregularis sp. nov. demonstrates an unexpectedly irregular and asymmetrical number of postocular scales: fivespecimens have two postoculars, four specimens have three postoculars, and three specimens have two postocularson the left side and three on the right side of the head.
Suggested common names: Chu Yang Sin Blind Skink (English); Thằn lằn giun Chư Yang Sin (Vietnamese),Chuyangsinskaya cherveobraznaya yascheritsa (Чуянгсинская червеобразная ящерица, Russian).
Nikita S. KLIUKIN, Andrey M. BRAGIN, Tan Van NGUYEN, Duy Dinh VU, Son Xuan LE, Vladislav A. GORIN, Isaac W. KRONE, Nikolay A. POYARKOV. 2026. A New Species of Blind Skink (Squamata: Dibamidae: Dibamus) from Chu Yang Sin National Park, southern Vietnam, with the first description of a Dibamus clutch. Zootaxa. 5760(5); 501-528. DOI: doi.org/10.11646/zootaxa.5760.5.1 [2026-02-26]
