Lygodactylus andavambato, Vences & Herrmann & Multzsch & Gippner & Razafimanafo & Rahagalala & Rakotomanga & Rakotoarison & Glaw & Miralles, 2025

Vences, Miguel, Herrmann, Cecilia, Multzsch, Malte, Gippner, Sven, Razafimanafo, Delina, Rahagalala, Ny Ando, Rakotomanga, Sandratra, Rakotoarison, Andolalao, Glaw, Frank & Miralles, Aurélien, 2025, Revision of the Lygodactylus tolampyae complex, with descriptions of three additional new dwarf gecko species from Madagascar’s North West, Zootaxa 5665 (3), pp. 301-328 : 312-315

Lygodactylus andavambato sp. nov.

( Figs 6 , 9–10 )

Remark. Corresponds to L. sp. 25 of Gippner et al. (2021) and Vences et al. (2024).

Holotype. ZSM 74/2023 (field number ZCMV 15818), female, from Tsingy de Namoroka National Park , Petit Tsingy (east of the massif), 16.43541°S, 45.36837°E, ca. 125 m a.s.l., northwestern Madagascar, collected between 7:00 am and 9:00 am, on 8 October 2023, by A. Miralles, N. A. Rahagalala, A. Rakotoarison, D. Razafimanafo and A. Razafimanantsoa.

Paratypes (n=6). UADBA-ZCMV 15817 (MIRZC 1275), Tsingy de Namoroka , same data as holotype. ZSM 75/2023 (ZCMV 15851), collected in forested savannah with baobab trees at the eastern border of Tsingy de Namoroka National Park , approximately 20 min by walking to the east of a large temporary lake (no exact locality, lake coordinates: 16.43104°S 45.36611°E, ca. 120 m a.s.l.), between 08:00 and 09:30 pm, on 9 October 2023, by A. Miralles, N. A. Rahagalala, A. Rakotoarison, D. Razafimanafo, and A. Razafimanantsoa. UADBA-ZCMV 15878, ZSM 76/2023 (ZCMV 15886), UADBA-ZCMV 15887, all three collected from Tsingy de Namoroka National Park, Campsite 2, near Grand Tsingy (south of the Tsingy massif), 16.46933°S, 45.34853°E, ca. 145 m a.s.l., around 02:00 pm and between 07:00 and 10:00 pm, on 11th of October 2023, by A. Miralles, N. A. Rahagalala, A. Rakotoarison, D. Razafimanafo and A. Razafimanantsoa. ZSM 297/2018, Tsingy de Namoroka National Park, without further information, donated by H.-P. Berghof, collected in 2018 by local collectors .

Diagnosis. Lygodactylus andavambato sp. nov. is characterized as member of the L. tolampyae complex (and thereby distinguishable from all other Malagasy Lygodactylus not belonging to the complex) by combination of a mental scale semi-divided by a suture, broad contact of the posterior projection of the mental scale with the first infralabial scale, and three postmental scales; and absence of whorls on the tail. From all other species in the L. tolampyae complex, the new species is distinguished by its uniquely slender appearance (vs. more robust appearance), combined with regular dark–light alternating crossbands of similar width on tail (vs. absence of regular crossbands on tail or a few dark crossbands much narrower than intervening light areas); as well as presence of 3 internasal scales (2 in one specimen) vs. 1–2 internasals in all or almost all individuals of the other species; and a smaller relative eye diameter (ratio ED/SVL 0.05 in three of four specimens, vs. 0.06–0.08 in most specimens of all other species, which only very few individuals having a ratio of 0.05). Further differences, although usually with overlap of values, are as follows: distinguished from L. herilalai by a higher longitudinal count of ventral scales (LCVS 110–115 vs. 98–106); from L. morii by a lower longitudinal count of dorsal scales (LCDS 222–240 vs. 225–269) and a smaller posterior contact between mental and first infralabial scale (relative PMS 15.1–29.4 vs. 28.5–49.5); from L. schwitzeri by a lower longitudinal count of dorsal scales (LCDS 222–240 vs. 240–271); and from L. tolampyae , by a relatively longer hindlimbs (ratio HIL/SVL 0.49–0.63 vs. 0.45–0.52). From a molecular perspective, the new species is characterized by numerous diagnostic nucleotide positions in the mitochondrial 16S rRNA gene (see Table 2).

Description of the holotype. Female, in good state of preservation, left front-limb removed as tissue sample, tail present ( Figs 9–10 ). SVL 32.0 mm, TAL 37.9 mm; for other measurements, see Table 3. Body width (6.4 mm) is slightly larger than head width (5.3 mm). The distance from the tip of the snout to the anterior border of the eye (4.7 mm) is larger than the anterior interorbital distance (4.6 mm), and greater than the distance between the eye and ear opening (2.8 mm). Snout covered with granular scales slightly larger than those on the dorsum. Nostril surrounded by five scales: rostral, first supralabial, one postnasal and two supranasals. The mental scale is semi-divided; contact between posterior projection of mental scale and first infralabial scale is around 21.3% of the infralabial scale length; three symmetrical postmental scales, followed by five postpostmentals; seven infralabial scales; six or seven supralabial scales; three internasal scales; granular dorsal scales; dorsum with small, homogeneous, granular, and unkeeled scales of similar size to those on trunk, slightly larger on limbs; 222 dorsal scales longitudinally along the body; 111 ventral scales between mental and cloaca; venter with larger homogeneous smooth scales; first finger present, small, but bearing a claw; three pairs of subdigital lamellae on the fourth toe; no dorsolateral tubercles; no observable lateral spines at the base of the tail.

After one year of preservation in ethanol ( Fig. 9 ), the specimen is grayish in colouration with a slightly darker middorsal stripe and six pairs of small dark dots running along the spine from the neck to the hip. On the head is a darker spot, from which the gray stripe appears to start. The limbs are spotted with small darker dots like the pairs running along the spine, toes are striped. The dorsal tail is banded in alternating darker and brighter grayish stripes as otherwise among Malagasy Lygodactylus they are only found in the unrelated L. rarus . Each side of the neck may have a whitish tubercle but almost not distinguishable from the rest of the neck. The ventral side of the body and limbs as well as the throat is uniformly whitish, the ventral side of the tail is more grayish. A visible dark blue spot is probably not integument colouration but organs visible through the skin. In life ( Fig. 6 ), colouration appears more intense and higher in contrast. Dorsum appears to be more patterned showing additional brownish and yellowish colors. Dark pairs of spots are also visible medially on dorsum in life photos. Photo of ventral coloration in life is not available.

Variation. All photographed specimens ( Fig. 6 ) share the overall slender appearance of the holotype, the gray, poorly patterned dorsum, and the rather distinct and regular crossbands on tail. This also applies to additional specimens photographed by I. Ineich (specimen with field number 1777I), and by H. P. Berghof and A. Hartig at Namoroka which, although not genotyped, almost certainly belong to this species. For morphometric and meristic data of two paratypes, see Table 3.

Etymology. The species epithet is derived from the Malagasy word “lavabato,” which refers to caves formed in the limestone karstic rock formations. The term “an-davambato” means “living in a cave,” indicating that the species was discovered in these unique geological formations. The name is used as a noun in apposition.

Habitat and natural history. All specimens have been collected while they were active, at night or in the morning. In Grand Tsingy (Great Tsingy), specimens have mainly been collected on large and smooth whitish limestone walls, at eye-level, either at the entrances of caves or along relatively dark corridors of fresh air running right through the massif. In Petit Tsingy (Little Tsingy), the holotype ZSM 74/2023 (ZCMV 15818) and the paratype UADBA-ZCMV 15817 were found in rocky fissures, close to the entrances to dark cavities. Several other specimens have also been collected outside of the very heart of the Tsingy massif, in different localities of the neighboring savannah. ZSM 75/2023 (ZCMV 15851) has for instance been found in a baobab forested savannah with scattered relictual fragments of karstic formations (highly degraded boulders, made up of clusters of rock slabs tightly packed into one another), therefore suggesting that L. andavambato is not a strictly cavernicolous species, but might rather be a small-sized saxicolous gecko needing narrow crevices to shelter.

Both Petit and Grand Tsingy share in common a typical Tsingy profile, i.e. a karstic plateau where groundwater has gouged a dense network of caverns, canyons and fissures into the limestone, and which are connecting open-air chambers of varying size, sunshine and vegetation. However, the Petit Tsingy area differs from the Grand Tsingy area by a denser network of corridors that are narrower (ranging from 0.5 to 2 m wide versus several meters wide) and shallower (2–6 m high vs. 10–20 meters high). According to local guides, both localities can be abundantly flooded during the rainy season, as evidenced by marks on the limestone walls indicating a temporarily high waterlevel (around two meters above the ground) and the presence in many places of aquatic snail shells remaining on the ground. Although we did not record temperatures, the Grand Tsingy appears to be substantially cooler than the Petit Tsingy, as even during the dry season (November), it benefits from a natural air-conditioning effect generated by the surrounding network of caverns where a few water reservoirs still remain.

Distribution. Lygodactylus andavambato is present in most of the localities we have visited in Namoroka (at Petit Tsingy and Grand Tsingy, which are more than 4 km apart, and also in two localities in the surrounding savannahs), suggesting this species is widely distributed within the area of the massif and locally common.

Figures

FIGURE 6. Specimens of Lygodactylus andavambato sp. nov. in life, photographed in October 2023 in Namoroka National Park. A–C, holotype ZSM 74/2023 (field number ZCMV 15818); D, paratype UADBA-ZCMV 15878.

FIGURE 9. Dorsal and ventral views of the preserved name-bearing types of three new species of the Lygodactylus tolampyae complex described herein.

FIGURE 10. Lateral and ventral views of the head of the preserved name-bearing types of three new species of the Lygodactylus tolampyae complex described herein (not to scale). The images of the ventral views have been modified by a sharpening filter to better appreciate the boundaries between scales. Inset images show enlarged views of the mental (light green), first infralabial (dark green) and postmental (light blue) scale arrangements in the three specimens. The small red arrow points to the contact between posterior projection of mental and first supralabial which is typically broad in the L. tolampyae complex (only moderate in L. andavambato sp. nov.).