MADAGASCAR – Boeny Region • 1 adult ♀; Tsingy de Namoroka National Park, Petit Tsingy; 16°26’7”S, 45°22’6”E; 125 m a.s.l.; 08 Oct. 2023, 07:00–09:00 a.m.; A. Miralles, N.A. Rahagalala, A. Rakotoarison, D. Razafimanafo and A. Razafimanantsoa leg.; ZSM 116/2023 (ZCMV 15819).

MADAGASCAR – Boeny Region • 1 tissue sample (MIRZC 1217, voucher not collected); Tsingy de Namoroka National Park, Grand Tsingy, south of the Tsingy massif, Camp 2; 16°28’9”S, 45°20’54”E, 128 m a.s.l.; 10 Oct. 2023, 03:00–07:00 p.m.; A. Miralles, N. A. Rahagalala, A. Rakotoarison, D. Raza­fi­manafo and A. Razafimanantsoa leg. • 1 specimen pho­to­graphed (unsampled and uncollected); Tsingy de Na­mo­roka National Park, Grand Tsingy; 16°28’1”S, 45°21’0”E; photographed by Ivan Ineich on 3 Sept. 2012.

Furthermore, four specimens deposited in the UMMZ collection and registered as Madascincus intermedius (junior synonym of M. polleni) have been collected only 50 m from the sample MIRZC 1217. Given their collection locality and the superficial resemblance between M. polleni and M. minotaurussp. nov., we hypothesize that these specimens likely correspond to the new species: UMMZ 222106–222109, from Namoroka, camp 1, at the edge of Tsingy (16°28’11”S, 45°20’54”E); Dec. 1996; C.J. Raxworthy, J.B. Ramanamanjato, A. ­Razafimanantsoa and J. Rafanomezantsoa leg. These specimens/samples are not designated as paratypes because the specimens were not studied.

Madascincus minotaurussp. nov. differs from all other species in the genus Madascincus by the combination of a lower number of scales around midbody and a higher number of ventrals. It differs from the species of the melanopleura group (its sister clade formed by M. melanopleura, M. ankodabensis and M. minutus) by a distinctly higher number of ventrals (68, versus 55 to 63) and paravertebral scales (69, versus 51 to 65), by a bell-shaped frontal scale (versus hourglass-shaped, i.e., frontal constricted by the first pair of supraoculars) and a distinct, lighter and warmer coloration (versus darker and brownish).

(Figs 3, 4) An adult female, with a single large egg in the abdominal cavity. Good state of preservation, with exception of the left arm and the left leg that have been removed for molecular analyses. SVL (39.9 mm) 7 times head length (5.9 mm), almost as long as tail (41.0 mm, either entire or completely 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 on lateral aspect, with a rostral tip bluntly rounded in dorsal aspect. Rostral wider than long, contacting first supralabial scales, nasals, and supranasal scales. Paired supranasal scales in median contact, contacting loreals and postnasal scales. Frontonasal scales roughly triangular, wider than long, contacting loreals, first supraciliaries and first supraoculars. Prefrontals absent. Frontal longer than wide, wider posteriorly, in contact with frontonasal, supraoculars, parietals and interparietal. Four supraoculars, all of them in contact with frontal; second pair larger than posteriormost pair; first pair not constricting frontal (frontal bell-shaped sensu Andreone and Greer 2002). Frontoparietals absent. Interparietal as long as wide, well separated from supraoculars; parietal eyespot present with parietal eye evident. Parietals contact posterior to interparietal. Two pairs of enlarged nuchals, each nuchal scale width corresponding to two transverse rows of adjacent cycloid scales. 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 long as high, single. Presubocular roughly square, single. Six supraciliaries on both sides, in continuous row; first and last pairs significantly larger than the intermediate ones; last pair projecting onto supraocular shelf. Pretemporals single, contacted by parietal. Two postsuboculars; upper contacting pretemporal; both contacting penultimate supralabial. Lower eyelid moveable, with a spectacled translucent window; lower palpebrals small, longer than high. Contact between upper palpebrals and supraciliaries seemingly direct but flexible, i.e., palpebral cleft narrow. Primary temporal single. Two secondary temporals; upper long, contacting 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 rounded, 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; 20 longitudinal scale rows at midbody; 69 paravertebrals, similar in size to adjacent scales; 68 ventrals. Inner preanals overlapped by outer. Both anterior and posterior limbs pentadactyl; fingers and toes relatively short, clawed, except the fifth finger which does not bear a claw; relative length of toes in the following order: I<II<III<V<IV. Subdigital lamellae smooth, single, with 7 under right fourth finger, 15 under right fourth toe.

In preservative, specimen with a pair of lateral dark brown stripes (about one scale wide on the neck), well defined anteriorly (overlapping rostral, mental, first four supralabials, loreals, and presuboculars), then progressively breaking up into a thin dashed lines posteriorly to forelimbs, hardly distinguishable from the rest of the dark dots covering the dorsum and the flanks. Presence on the anterior part of the body of a pair of short light cream dorsolateral stripes, separating the dark lateral stripe from the bronze dorsal field, well-visible from supranasals, supraciliaries, temporal area and the neck to the level of the insertion of the forelimbs, but progressively fading and disappearing posteriorly. Dorsum and dorsal sides of forelimbs, hindlimbs and tail light bronze. The bronze dorsal field and the slightly lighter flanks are covered by numerous little dark dots, with each cycloid presenting a distinctive lunular at their insertion point and a cloud of tiny dark pigmentations at their middle, resulting in many thin dash lines (14 at midbody). No distinct border between the background coloration of the darker dorsal and the lighter ventral sides. Immaculate light cream ventral field extending from lower side of head (mental excluded), throat, lower side of limbs and venter, to ventral side of tail. Palms and soles greyish, darker than venter. In life, the coloration pattern was relatively similar to that in preservative, but with a slightly brighter and warmer overall aspect, evoking more a copper than bronze background coloration. Light dorsolateral stripes on the head and the neck were more discernable and extending along the entire length of the body until hindlimbs insertion and presenting a brighter orange tint. Presence of slightly iridescent glints of scales (cf. Fig. 3A, B).

The only available additional information concerns a specimen photographed by Ivan Ineich at the Grand Tsingy; it presents a color pattern identical to that of the holotype (Fig. 3C).

The specific epithet minotaurus, invariable noun in apposition, is derived from Minṓtauros (ancient Greek: Μινώταυρος), a taurine creature of the Greek mythology. It alludes to the labyrinthine structure of the Tsingy de Namoroka, within which the new species, like the Minotaur in Daedalus’s construction, appears unable to escape.

(Figs 5, 6, 9) Only known from the ­Tsingy area of the Namoroka National Park, North West of Madagascar, and probably distributed all over this karstic massif and surrounding patches of deciduous forest. The holotype was collected at the border of the Petit Tsingy (eastern part of the Namoroka massif), at the limit between the rock corridor and the adjacent dry deciduous forested area. The sample MIRZC 1217 was found on the border of the Grand Tsingy (southern part of the massif).

The two specimens observed in 2023 were foraging in dense leaf-litter layers in shaded areas (by day) or active at dusk.

Considering that Madascincus minotaurussp. nov. is likely widely distributed across the Namoroka karst massif, and based on satellite imagery, it is possible to conclude that its EOO might at least range from 50 to 200 km², depending on whether the species is present in peripheral karstic isolates too (cf. Fig. 6). The possibility of a broader distribution within the region for this species remains however plausible and cannot be dismissed in the absence of additional data. Although the Namoroka massif is well preserved and currently shows no significant signs of anthropogenic disturbance, the new species’ habitat is likely highly fragmented. Pending further information to confirm this species’ range, population status, and potential threats, we recommended assigning the species the status VU (Vulnerable) based on the criteria D2 of the IUCN Standards and Petitions Committee (2024).

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).

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.

Madascincus irerysp. 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).

(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).

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.

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.

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).

In 2019, the holotype of M. irerysp. 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. 12C). 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.

Considering that Madascincus ­irerysp. nov. is likely widely distributed across the Lokobe reserve, its EOO might be at least of 7.4 km² (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 irerysp. nov. is extremely restricted (possibly less than 10 km²), 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 D2 of the IUCN Standards and Petitions Committee (2024).