Plestiodon tamdaoensis (Bourret, 1937)

Specimen examined.

• One subadult, collected on 28 August 2024 on the forest trail near Old Church (21 ° 04 ' 23.6 " N, 105 ° 21 ' 56.9 " E, at an elevation of 810 m), Ba Vi NP, Vietnam.

Description.

Morphological characters of the specimen from Ba Vi NP agreed well with the descriptions of Bourret (1937), Hikida et al. (2001), and Hech et al. (2013): SVL 30.5 mm; TaL 46.5 mm (n = 1). Supranasals large, in contact with each other; frontoparietals in contact with each other; interparietal larger than frontoparietals; parietals separated; two pairs of nuchal scales; four supraoculars; postnasal single; three loreals; lower eyelid scaly; eight supraciliaries; eight supralabials; seven infralabials; tympanum deeply sunk, with three small lobules on the anterior edge; midbody scales in 24 rows, smooth; paravertebral scales 45; 52 transverse rows of ventrals, smooth; precloacals two, enlarged; fingers and toes meeting when adpressed; subdigital lamellae under fourth finger 13 and 19 under fourth toe.

In life, dorsal surface of head and body black with two cream stripes on body; lateral band black-brown with one cream stripe on each; all stripes extend from head to base of tail; dorsal surface of tail bright green; ventral surface light brown (Fig. 1). In preservative, dorsal surface of head, body, and tail brown with two cream stripes on body; lateral band black-brown; ventral surface light brown.

Ecological notes.

The specimen was found at 10: 00 on the ground at elevations of 810 m a. s. l. The surrounding habitat was a disturbed evergreen forest of medium hardwood, bamboo forest, and shrub. The humidity was approximately 75–85 %, and the air temperature ranged from 26 to 32 ° C.

Potential distribution.

MaxEnt models showed great prediction power for the distribution of the skinks, with average AUC values> 0.91 for P. tamdaoensis. The optimal model had the regularization multiplier value of 2.5 and a combination of linear and quadratic feature classes and an AUC value of 0.9142. However, the regularization multiplier value of 2.5 for the optimal model means that the final model was slightly generalized. The final prediction should therefore be carefully interpreted as potential zones, and it may include regions that are not likely to have any P. tamdaoensis populations, especially in the edge areas. The model also encompassed all known records of the skink, including new localities (Fig. 2). The model also showed that the potential distribution of P. tamdaoensis can be as large as 110,000 km 2, significantly expanding its known range compared to the IUCN range map.