Hemidactylus faustus, Lobón-Rovira & Conradie & Iglesias & Ernst & Veríssimo & Baptista & Pinto, 2021

Lobon-Rovira, Javier, Conradie, Werner, Iglesias, David Buckley, Ernst, Raffael, Verissimo, Luis, Baptista, Ninda & Pinto, Pedro Vaz, 2021, Between sand, rocks and branches: an integrative taxonomic revision of Angolan Hemidactylus Goldfuss, 1820, with description of four new species, Vertebrate Zoology 71, pp. 465-501 : 465

Hemidactylus faustus sp. nov.

Fig. 15 , 16

The phylogenetic analysis revealed that Hemidactylus faustus sp. nov. clusters within a large clade, which includes the H. nzingae -group, H. bayonii -group, H. benguellensis -group, and H. pfindaensis , although its phylogenetic position is not well-stablished (Fig. 2 ). However, according to the morphological and genetic analysis performed, this species represents a well-differentiated clade from H. bayonii -group and H. benguellensis -group, with 17.85% and 16.72% uncorrected p-distance, respectively (Table 1 ). This species represents a micro-endemic form only known from a unique geological formation, possibly a relic species confined to the massive conglomerate inselbergs of Pungo Andongo and surrounds, in Malanje Province. Due to their exclusive morphological characteristics and the elusive behavior of the species, we consider that no other specimens have been reported before and mistaken with any of its congeners.

Holotype.

ANGOLA • 1 ♀; Malanje Prov., Pungo Andongo; -9.67333°, 15.59222°; 1217 m a.s.l.; 11 Jul. 2019; Pedro Vaz Pinto and Javier Lobón-Rovira; good condition with partially regenerated tail; FKH0281.

Paratypes.

ANGOLA • 1 ♂; same collecting details as holotype; MNCN50534 • 2 ♀; same collecting details as holotype; MNCN50535 and ZMB 90447 • 1 ♀; same collecting locality as holotype; 11 Aug. 2018; Beatriz Vaz Pinto; FKH0023.

Additional material examined.

ANGOLA • 1 ♀; same locality as type material; 11 Aug. 2018; Pedro and Afonso Vaz Pinto; ZMB 90446 • 1 ♂, juv.; same collecting details as previous material; ZMB 90445 • ♀; same locality as type material; 15 Oct. 2020; Pedro Vaz Pinto; MNCN 50536 .

Diagnosis.

A robust medium sized Hemidactylus , with SVL of 39.4 mm (mean) and maximum width of 7.4 mm (Fig. 15 ). 8-9 supralabials and 7-8 infralabials. Dorsal pholidosis with 15-17 rows of moderate keeled tubercle scales and ventral pholidosis with 29-32 smooth and rounded scale rows around midbody. Hemidactylus faustus sp. nov. present a moderate, triangular mental scale, two large postmentals followed by two large post-postmentals. Tail with thickness at the base tail with conical tubercle rows laterally. Regenerated tail with regular larger scales. Males with 17-19 continuous precloacal-femoral pores. Five or six divided scansors beneath the first digit of both manus and pes, seven beneath the fourth digit of manus, eight or nine beneath the fourth digit of pes. Dorsum coloration with two darker dorsolateral bands from the occiput to the tail, which includes 5 W-shaped darker crossbands in contact with both lateral bands; each dark crossbar is separated by lighter blotches.

Comparative diagnosis.

Head slightly more quadrangular than the other members of the Angolan Hemidactylus (HL/HW ≤1.4 vs.>1.5 Angolan congeners) and regenerated thickened tail found in all specimens collected (n=8), a feature never recorded among Angolan congeners. It can be distinguished from the other non-Angolan western and central Africa congeners based on the same characteristics of the other Angolan species ( Ceríaco et al. 2020a). Hemidactylus faustus sp. nov. can be distinguished from Angolan congeners by the thickness at the base tail. Additionally, it could be distinguished from H. mabouia by the presence of smaller subcaudal scales, and from H. benguellensis -group by lower number of precloacal-femoral pores (17-19 vs. 23-33 in H. benguellensis , and 26-28 H. cinganji sp. nov.), less keeled tubercle rows, smaller maximum length (45.3 mm [mean=39.8] vs. 54.5 [mean=47.5]), the dark dorsal uniform color with dorsolateral light stripes and absence of dorsolateral orange tubercle rows (present in H. benguellensis -group). It differs from H. carivoensis sp. nov. by the absence of keeled subcaudal scales, less keeled dorsal tubercle rows, and dark dorsal uniform color with dorsolateral light stripes and absence of dorsolateral orange tubercle rows. Hemidactylus faustus sp. nov. differs from the H. longicephalus -group by having smaller SVL (maximum length 45.3 mm [mean=39.8] vs. 60.08 [mean=46.57] in H. longicephalus and 64.8 [mean=58.96] in H. paivae ), larger number of precloacal-femoral pores (17-19 vs. 6-11 in H. longicephalus and 6-8 in H. paivae ) and lower number of granular scales between the dorsal tubercles (2-3 vs. 3-6 in H. longicephalus and 4-9 in H. paivae ). It differs from the H. bayonii -group by having a larger SVL (maximum SVL 45.3 mm [mean=39.8]), than H. bayonii 36.2 mm [mean=34.9] and H. vernayi (42.5 mm [mean=32.7]), and lower than H. nzingae (51.5 mm [mean=44.3]) and larger number of precloacal-femoral pores (17-19 vs. 4-9 in H. bayonii , 4-6 in H. vernayi , 7-8 in H. nzingae and 8 in H. gramineus ).

Holotype description (Fig. 15 ).

Measurements and meristic characters of the holotype are presented in Table S8. Adult female with a snout-vent-length (SVL) of 39.39 mm and regenerated tail length (TL) of 22.84 mm. Robust body, nape slightly distinct. Head slightly wider than the body and shorten (HW/HL 0.67). Canthus rostralis not prominent, but slightly marked. Eye diameter (3.05 mm), with vertical pupil and crenulated margin. Supraciliar scales small and pointed. Ear height (0.98 mm). Ear to eye distance slightly larger than orbit diameter (3.17 mm). Snout rounded. Frontal scales granular and of similar size as occipital scales. Occipital scales granular interspersed with large number of smooth and conical tubercle scales from eyes to nape. Rostral wider than deep (1.66 vs. 0.91 mm, respectively). Rostral semi divided posterodorsally, in contact with 1st supralabial, nostril, two postnasal and one internasal scales. 9 supralabial and 7 infralabials. First supralabial in contact with the nostril. Nostril circular rounded by rostral, supranasal, prenasal and 2 postnasals. Prenasal, postnasal and supranasal same size. One row of scales between supralabials and the orbit. Mental large, triangular, with two larges rectangular postmental scales in short contact posteriorly to the mental. 7 post-postmental scales, composed by 2 post-postmental half size of postmental scales in contact with postmentals and 1st and 2nd infralabials, and 5 small post-postmentals in contact with postmental scales. Gular scales half size than ventral scales and granular. Between the gular scales and infralabials a row of enlarged scales is present, decreasing in size towards the 5th infralabial where they become the same size as the gular scales.

Body robust and slightly short (TRL/SVL 0.41). Ventral scales widely larger than dorsal scales, with 31 scales across the belly. The dorsal pholidosis presents heterogenous conical, granular scales interspersed by 16 conical dorsal tubercle rows at midbody. Dorsal tubercle rows are separated by 3 granular scales. Tubercle scales reach the posterior part of the eye region where they lose the keeling progressively. Tubercle in the base of tail is well developed. Tail with lateral conical tubercle rows. Regenerated tail with regular larger scales (after precloacal) enlarged and 2 well-developed postcloacal spurs on each side.

Fore- and hindlimbs relatively short, stout; forearm medium sized (FL/SVL 0.23); tibia short (CL/SVL 0.18). Digits short and clawed. All digits of manus and pes indistinctly webbed. Scansors beneath toes and fingers are equally divided and composed by 1st scansor undivided and variable number of undivided terminal scansors. Number of scansors: 6-8-7-7-7 (right manus), 7-10-11-10-9 (right pes). Relative length of digits: V < IV < III > II > I (right manus); V < IV < III > II > I (right pes).

Variation.

Variation in scalation and body measurements of the paratypes and additional material of H. faustus sp. nov. are reported in Table S8. All the material examined is in concordance with the description of the holotype.

Coloration.

In life (specimen MNCN 50534; Fig. 16A ): this species displays a nocturnal greyish or brownish coloration above with two darker dorsolateral bands from the occiput to the tail, which includes 5 W-shaped darker crossbands in contact with both lateral bands; each dark crossbar is separated by lighter blotches; head with an irregular dark and light brownish patch and a dark brownish band from the narine to anterior portion of the forelimb; light beige ventrally and laterally, with scattered black speckles in the venter; upper and lower labials beige; limbs with irregular dark-and-light brownish patches; tail with similar color and slightly banded; iris silvered with a black narrow pupil and brownish-golden reticulation. During the day, this species presents a uniform pattern along the body. In preservative (Holotype; Fig. 15 ): dorsum with dark coloration and five spaced darker W-shaped crossbars from the occiput to the tail that could be difficult to distinguish, with lighter dorsolateral bands; ventrum light beige with scattered black speckles. Variation: from light brownish to totally dark dorsal coloration; cross-bands can be difficult to distinguish; ventrum can be uniform beige or have scattered black speckles.

Etymology.

The name " Hemidactylus faustus " applies to a Latin word that designate 'good luck’, evoking the serendipitous discovery of this species. The species epithet is used as a masculine adjective singular. The first specimen was found by Beatriz Vaz Pinto, daughter of PVP, under a small stone which was removed while preparing a campsite. This unexpected find led to further collecting of this new and previously unrecorded form, albeit from a locality that had been regularly surveyed since the mid-19th century.

Distribution and conservation (Fig. 16C ).

This species is likely a micro-endemic form, strictly associated with the conglomerate inselbergs of Pungo Andongo also known as Pedras Negras (Black Rocks), just north of the mid-Cuanza River in western Malanje Province, Angola (Fig. 16C ). At the moment the only know population occurs on this site, which covers approximately 4,000 ha of huge rocky conglomerate boulders. A similar and nearby inselberg system - Pedras Jingas, albeit smaller, shares identical geological features as Pungo Andongo, being situated some 20kms to the northeast. It is quite possible that the species is present at Pedras Jingas and also in a few smaller isolated inselbergs nearby, but these areas have not been surveyed yet. All considered, it is likely that H. faustus sp. nov. is contained within about 6,000 ha of suitable habitat in the region. However, due to the limited material confirmed to belong to this species, we cannot calculate the EOO and we regard the conservation status of this species as Data Deficient. This species needs further studies about the real extent of its range and current population trends to better address its conservation status. Due to its small distribution range and highly specialized niche this species may provisionally warrant a threat status.

Natural history and habitat (Fig. 16B ).

Hemidactylus faustus sp. nov. represents a ground-dwelling rupicolous species apparently associated with the unique geological formation of conglomerate massifs in northern Angola. It was found sheltering under small rocks or between the cavities created by plant roots growing on the flattened top of massive inselbergs, at around 1250 m a.s.l. Most specimens were collected at night foraging on the ground or at times climbing the sparse and stunted vegetation present, possibly hunting small spiders and other invertebrates. The specimens displayed an elusive behavior, jumping and disappearing quickly between the cavities and among vegetation roots when disturbed. The species occurs in sympatry with H. paivae (see Table S2 for H. paivae recorded localities), which occupies a different ecological niche, the latter living on the vertical and inaccessible walls of the conglomerate boulders. Both species could also be found in the rocky conglomerate base that makes the transition between various inselbergs. The site where the species was discovered lies within the Angolan Miombo Woodlands, even though the local ecological conditions can be considered atypical.

Figures

Figure 15. Holotype of Hemidactylus faustus sp. nov. (FKH 0281) from Pungo Andongo, Malanje Province, Angola. A - Ventral and dorsal view of body. B - Details of head in lateral, dorsal and ventral views (from top to bottom). C - Details of left toes and right fingers (from left to right). Photos by Pedro Vaz Pinto.

Figure 16. A - Dorsolateral view of Hemidactylus faustus sp. nov. (MNCN 50534). B - Pungo Andongo, habitat of H. faustus sp. nov. C - records of H. faustus sp. nov. (star depicting type locality and only known locality). Photos by Javier Lobon-Rovira.

Figure 2 A. Bayesian Inference (BI) phylogenetic tree based on ND 2 + RAG 1 concatenated data, with Maximum Likelihood (ML) support overlaid. Numbers above the key nodes indicates BI posterior probability (≥ 0.90 were considered supported), while below the key nodes indicate ML bootstrap values (≥ 75 % were considered supported). Major clades are marked with a thick vertical line.