Phylogeny of Mabuya, with a close-up of clades containing M. nigropunctata (blue) and both M. altamazonica and M. yasuniensis sp. nov. (red). All samples of M. yasuniensis correspond to paratypes. This maximum likelihood tree was obtained from an analysis of five genes (two mitochondrial, three nuclear) and 256 terminals. Numbers above branches are ultrafast bootstrap support values, not shown in short branches for clarity. Specimens sampled in this study are shown in bold. Taxon name (M.: Mabuya) followed by voucher number and country of origin are provided. BR: Brazil, CO: Colombia, EC: Ecuador, FG: French Guiana, LA: Lesser Antilles, PE: Peru, TT: Trinidad and Tobago, VE: Venezuela.

Four species of skinks Mabuya in life, from top to bottom: M. yasuniensis sp. nov. (QCAZ 14814, holotype, SVL = 72.98 mm), M. altamazonica (QCAZ 13087, SVL = 92.11 mm), M. nigropunctata (QCAZ 8107, SVL = 104.58 mm), and M. bistriata. Photographs from Bioweb.bio, except M. bistriata (Laurie J. Vitt).

Known distribution of Mabuya in Ecuador: M. altamazonica (squares), M. nigropunctata (circles), M. yasuniensis sp. nov. (triangles). Red-filled symbols correspond to localities of sequenced specimens. Red star indicates type locality of M. yasuniensis sp. nov.

Male holotype (QCAZ 14814; SVL = 72.98 mm) of Mabuya yasuniensis sp. nov. in dorsal (top), lateral (middle) and ventral (bottom) views. Photographs by D. A. Paucar. Scale bar: 10 mm.

Head of the holotype (QCAZ 14814) of Mabuya yasuniensis sp. nov. in dorsal (top), ventral (middle), and lateral (bottom) views. Photographs by D. A. Paucar. Scale bar: 5 mm.

Hemipenes of two male paratypes of Mabuya yasuniensis sp. nov. (top: QCAZ 4839, SVL = 77.46 mm; bottom: QCAZ 11832, SVL = 76.64 mm) in asulcate, sulcate and lateral views from left to right. Number labels correspond to characters described in the text based on Sánchez-Martínez et al. (2020). Photographs by D. A. Paucar. Scale bar: 2 mm.

Paratypes (top: QCAZ 4839, SVL = 77.46 mm; bottom QCAZ 17646, SVL = 54.81 mm) of Mabuya yasuniensis sp. nov. in dorsal and lateral views. Photographs by D. A. Paucar. Scale bar: 10 mm.