Madascincus irery Miralles, Scherz, Roberts, Rakotoarison, Glaw & Vences, 2026, sp. nov.

Abstract

Madascincus irery sp. nov. Figures 7, 8, 9, 10, 11, 12 Holotype. MADAGASCAR – Diana Region • unsexed specimen; Nosy Be, Lokobe National Park; 13°24’29”S, 48°18’31”E; ca. 210 m a. s. l.; 28 Apr. 2019, ca. 12: 00 a. m.; M. D. Scherz, F. Glaw, A. Razafimanantsoa and J. H. Razafindraibe leg.; ZSM 135 / 2019 (FGZC 5612). Paratype. MADAGASCAR – Diana Region • 1 unsexed specimen; Nosy Be, Lokobe National Park; 13°24’31”S, 48°20’8”E; ca. 90 m a. s. l.; 18 Feb. 2015; “ Frontier Madagascar ” team leg.; ZSM 86 / 2015. Diagnosis. Madascincus irery sp. nov. differs from all other species in the genus Madascincus (except those of the nanus group) by a lower number of ventral scales (55, versus 56 to 88), a short and pointed snout with visibly enlarged eyes and a dark and uniform coloration (versus lighter coloration, most often with dark lateral stripes variable in contrast and length). Additionaly, it differs from the species of the nanus group by a higher number of scales around midbody (24, versus 18 to 20), and more elongated digits, with both a higher number of subdigital lamellae under the fourth finger (8, versus 3 to 5) and the fourth toe (12 to 15, versus 5 to 8). It differs from the species of the polleni group (its sister clade, formed by M. polleni, M. arenicola, M. stumpffi and M. miafina) by a distinctly lower number of ventral scales (55, versus 65 to 88) and of paravertebral scales (53 to 56, versus 65 to 88), a smaller size (33.8 to 39.9 mm, versus 54.9 to 89.6 mm), an hourglass-shaped frontal, i. e., constricted by the first pair of supraocular (versus always bell-shaped in all species except in M. stumpffi, where this state of character is variable), and a lower number of subdigital lamellae under the fourth toe (12 to 15, versus 15 to 23). Description of the holotype. (Figs 10, 11) Presumably adult specimen, in an overall good state of preservation, with exception of the right hindlimb, which has been cut off as tissue sample, and a longitudinal row of approximately 20 scales ripped out on the left side of the body. A rather small Madascincus species with relatively large eyes and short and pointed snout. SVL (33.8 mm) 7 times head length (5.9 mm), almost as long as tail (41.0 mm, apparently entire and not regenerated). Limbs very short: SVL 7.1 times forelimb length (5.5 mm) and 4.3 times hind limb length (8.9 mm). Snout short and rounded in lateral aspect and dorsal aspect. Rostral wider than high / long, contacting first supralabial scales, nasals, and supranasal scales. Paired supranasal scales in median contact, contacting loreals and postnasals. Frontonasal roughly triangular, wider than long, contacting loreals, first supraciliaries and first suprocular scales. Prefrontal scales absent. Frontal longer than wide, wider posteriorly, in contact with frontonasal, supraoculars, parietals and interparietal. Four supraoculars, all of them in contact with frontal; the second and third pairs larger than the anteriormost and posteriormost pairs; the first pair weakly constricting frontal (frontal hourglass-shaped sensu Andreone and Greer 2002). Frontoparietals absent. Interparietal longer than wide, well separated from supraoculars; parietal eyespot present with parietal eye evident. Parietals contact posterior to interparietal. Enlarged nuchals absent. Nasals slightly larger than nostrils; contacting rostral, first supralabials, postnasals and supranasals. Postnasals present, separating supranasals from first supralabials, and nasals from loreals. Loreal single, slightly higher than long. Preocular trapezoidal, as longer as high, single. Presubocular roughly triangular, elongated, single. Seven supraciliaries on both sides, in continuous row; first and last pairs significantly larger than the intermediate ones; last pair projecting onto supraocular shelf. Two pretemporals. Two postsuboculars; upper contacting lower pretemporal; both contacting penultimate supralabial. Lower eyelid moveable, scaly; lower palpebrals small, longer than high, interdigitating with large polygonal scales of central eyelid. Contact between upper palpebrals and supraciliaries seemingly direct but flexible, i. e., palpebral cleft narrow. Primary temporal single. Two secondary temporals; upper contacting lower pretemporal anteriorly and overlapping lower secondary temporal ventrally. Six supralabials, with the fourth being the enlarged subocular, contacting scales of the lower eyelid. External ear opening small, higher than wide, without lobules. Mental wider than long, posterior margin convex. Postmental wider than long, contacting first two pairs of infralabials. Six infralabials. Three pairs of large chin scales, both members of first pair in contact, both members of second pair separated by a single median scale, and members of third pair separated by three scale rows. No scales extending between infralabials and large chin scales. Gulars similar in size and outline to ventrals. All scales, except head shields and scales on palms, soles, and digits, cycloid, smooth, and imbricate; 24 longitudinal scale rows at midbody; 53 paravertebrals, similar in size to adjacent scales; 55 ventrals. Inner preanals overlapped by outer. Both anterior and posterior limbs pentadactyl; fingers and toes clawed; relative length of toes in the following order: I <II <III <V <IV. Subdigital lamellae smooth, single, with eight under both fourth finger, 12 under left fourth toe. Coloration of the holotype. In preservative, specimen with a relatively uniform bronze coloration on the dorsal side from head to tail, slightly darker along two barely visible paravertebral lines, progressively fading on the flanks to become an immaculate light cream coloration on the ventral side. Palms and soles barely darker than the rest of the ventral side. In life, the coloration pattern was relatively similar to that in preservative, with however a slightly brighter and warmer overall aspect. The scales in life were iridescent (Fig. 10). Variation. The paratype ZSM 0086 / 2015 is generally very similar to the holotype (Fig. 11). It has the following traits: SVL 39.9 mm, width at midbody 5.3 mm, tail length 52 mm, hindlimb 10.5 and 9.5 mm (right and left, respectively), 13 and 15 subdigital lamellae under the fourth toes, 55 ventrals, 56 dorsals, 24 scales around midbody. Etymology. The specific epithet irery, invariable noun in apposition, is derived from the Malagasy language, and means “ alone ” or “ solitary ”. It refers both to the assumption that this species seems to be isolated on the small island of Nosy Be and the fact that it represents a distinct long phylogenetic branch. Distribution. Only known from Lokobe National Park (east and west, and therefore likely widespread across the park) on Nosy Be (Fig. 12). Surveys on the adjacent island of Nosy Komba failed to find this species (Hyde Roberts and Daly 2014; Blumgart et al. 2017). Ecology. In 2019, the holotype of M. irery sp. nov. was collected active around noon on 28 April, on a boulder field next to a small stream on the Circuit Mitsinjo within Lokobe National Park. The microhabitat was characterized by large boulders covered in moss and liverworts (Fig. 12 C). This kind of habitat occurs in several locations within Lokobe, which is comprised mostly of lowland moist evergreen forest, but our brief survey did not find the species elsewhere. Far more comprehensive fieldwork is needed to establish the spread of the species within the park, and surveys in other forest fragments on the island should be carried out to establish whether it occurs outside the park. Conservation status. Considering that Madascincus irery sp. nov. is likely widely distributed across the Lokobe reserve, its EOO might be at least of 7.4 km ² (Andreone et al. 2003). The possibility of a broader distribution within Nosy Be island for this species remains however plausible and cannot be dismissed in the absence of additional data. The Lokobe area exhibits a largely intact forest cover, and direct anthropogenic pressures in its central protected areas remain limited. However, the distribution range of Madascincus irery sp. nov. is extremely restricted (possibly less than 10 km ²), warranting particular attention and regular monitoring to assess its global risk of extinction. Pending further information to confirm this species’ range, population status, and potential threats, we recommend to assign the species the status VU (Vulnerable) according the criteria D 2 of the IUCN Standards and Petitions Committee (2024).