Hemidactylus vernayi, Ceríaco & Agarwal & Marques & Bauer, 2020

Ceríaco, Luis M. P., Agarwal, Ishan, Marques, Mariana P. & Bauer, Aaron M., 2020, A correction to a recent review of the genus Hemidactylus Goldfuss, 1820 (Squamata: Gekkonidae) from Angola, with the description of two additional species, Zootaxa 4861 (1), pp. 92-106 : 100-104

Hemidactylus vernayi sp. nov.

( Fig. 5 )

lsid: http:// zoobank.org:act: 749CA24D-F3D6-4DAF-8818-EC48CF90D884

Hemidactylus bayonii [part]: Ceríaco et al. (2020:20)

Ceríaco et al. (2020) designated a neotype for H. bayonii based on specimens from Kissama National Park, south of Luanda, and provided an updated diagnosis for the species. According to the molecular results presented in the latter revision, H. bayonii extends from coastal regions of Luanda to Kwanza Sul Province, central Angola. The authors tentatively assigned four specimens from Benguela Province (AMNH 47770–1, 47778, 47780), collected in 1925 during the Vernay Angola Expedition, as well as three specimens from Lucira, northern Namibe Province (TM 24447, 24450–51) to H. bayonii . A re-evaluation of the four specimens from Benguela Province reveal that this population has a lower number of femoral pores, a more robust cephalic region and a different coloration pattern ( Table 1 , Fig. 3 ). Based on these characters we describe these specimens as a new taxon. The Lucira specimens housed in the TM were not consulted in the present comparison and need to be carefully reviewed before assigning them to any of the exiting taxa.

Holotype. AMNH 47770 ( Fig. 4 ), adult male, Lobito (-12.33333º, 13.583331º, <5 m), Benguela Province, collected by Rudyerd and Laura Boulton on 24 April 1925.

Paratypes. AMNH 47771 , adult male with the same collection data as holotype, but collected on 27 April 1925 ; AMNH 47778 , adult male collected in Hanha do Norte (-13.266667º, 14.166667º, 919 m), Benguela Province, collected by Rudyerd and Laura Boulton on 18 May 1925 ; AMNH 47780 , adult male with the same collecting data as the previous specimen, but collected on 17 May 1925 .

Diagnosis. A small sized Hemidactylus , maximum snout-vent length 36.7 mm ( Fig. 3 ). Dorsal pholidosis heterogeneous, with 11–14 irregularly arranged longitudinal rows of subtrihedral, striated, keeled tubercles at midbody. Two well-developed pairs of postmentals, the inner pair longer than the outer pair, about the same size as the mental, in broad contact behind mental. Ventrolateral folds distinct, about 28–31 scale rows across venter. Six divided scansors beneath first digit manus, seven to that of pes, seven beneath fourth digit of manus, nine to ten beneath the fourth digit of pes. Four to five continuous precloacal pores in males. Body dorsum brownish (from light to dark), without transverse markings, cream-colored stripe extending from snout to behind the eyes.

Description of the Holotype. The holotype is in good condition but without tail ( Fig. 3 ). Detailed measurements and meristic characters of the holotype are presented in Table 3 . Head medium (HL/SVL 0.27), moderately wide (HW/HL 0.60), moderately raised (HH/HL 0.45), distinct from neck. Loreal region inflated, canthus rostralis slightly prominent. Snout medium (SE/HL 0.39); almost double the size of eye diameter; scales on snout, canthus rostralis, forehead and between eyes homogenous, juxtaposed, and weakly pointed; scales on snout, canthus rostralis and forehead three to four times the size of those on the occipital and interorbital regions, canthus rostralis with slightly enlarged patch of scales. Eye small (ED/HL 0.21); pupil vertical with crenulated margins; supraciliaries small, pointed, those at the anterior end of orbit slightly larger. Ear opening oval (greatest diameter 0.9 mm); eye to ear distance larger than diameter of eye (EE/ED 1.33). Rostral wider than deep, without marked rostral groove; two enlarged internasals, separated by one scale, one supranasal on each side which is smaller than internasal, one pair of still smaller postnasals; rostral in contact with nostril, supralabial I, supranasal and internasal; nostrils small, oval, each surrounded by supranasal, internasal, rostral, and postnasal; 1–2 rows of scales separate orbit from supralabials. Mental triangular, two well developed postmentals, the inner pair the same size as mental and in extensive contact with each other behind mental; outer pair about 2/3 the size of the inner pair, separated from each other by inner pair and four gular scales, one much larger than the three others. Inner postmental bordered by mental, infralabial I, outer postmental and three gular scales; outer postmental bordered by infralabials I, infralabial II, inner postmental, and six/seven gular scales of which the outer two are much enlarged and continue as two rows of enlarged scales below infralabials. Infralabials bordered by a double row of enlarged scales. Supralabials (to midorbital position) 10 (right)/9 (left); infralabials (to angle of jaw) 8 (right)/ 8 (left). Body moderately elongate (TRL/SVL 0.37), with distinct ventrolateral folds. Dorsal pholidosis heterogeneous, composed of conical, granular, striated scales intermixed with enlarged, fairly regularly arranged, longitudinal rows of 14–16 subtrihedral, weakly keeled, striated tubercles at midbody, extending from occipital region to tail, each enlarged tubercle roughly two to three times longer than adjacent granules, surrounded by rosette of 9–10 small granules, 2–4 granules between two adjacent enlarged tubercles; enlarged tubercles on nape and shoulder small and pointed, those on occipital, temporal region still smaller. Ventral scales hexagonal, larger than dorsal, smooth, imbricate; midbody scale rows across belly 30–31; gular region with still smaller, sub-imbricate scales, those on lateral aspect of neck granular, anterior gular scales slightly larger than the rest. Four precloacal pores. Scales on the palm and sole smooth, imbricate, rounded; scales on dorsal aspect of upper arm larger than granules on dorsum, subimbricate and striated, dorsal aspect of forearm with smaller, striated, conical and granular scales, intermixed with a few enlarged conical tubercles.

Fore- and hindlimbs relatively short, stout; forearm short (FL/SVL 0.15); tibia short (CL/SVL 0.16); digits moderately short, strongly clawed; all digits of manus and digits I–IV of pes indistinctly webbed; terminal phalanx of all digits curved, arising angularly from distal portion of expanded lamellar pad, half or more than half as long as associated toepad; scansors beneath each toe in straight transverse series, divided except for distal and three to four basal scansors on digit I and one or two on all digits that are single; scansors from proximal most at least twice diameter of palmar scales to distalmost single scansor: 6-7-7-7-6 (right manus), 5-9-9-9-8 (right pes). Relative length of digits: IV> V = III = II> I (right manus); V> III = IV> II> I (right pes).

Coloration (in preservative). Dorsum of an irregular pattern of light brown and dark brown, and mostly continuous cream dorsolateral stripes. Crown of head light brown with scattered dark brown scales. A cream stripe extending from nostril to midorbital rim, through eye, and on to temporal region.Infralabials and posterior supralabials pale, anterior supralabials with scattered dark pigment. Forelimbs and hindlimbs brown. Venter immaculate white; palms and soles brownish.

Variation. Variation in scalation and body measurements of the paratypes of H. vernayi sp. nov. is reported in Table 3 . The majority of the paratypes do not differ in any important details from the holotype.

Comparison with West and Central African congeners. Hemidactylus vernayi sp. nov. is readily distinguished from H. kamdemtohami and H. richardsonii by the lack of basal digital webbing; it is distinguished from H. matschiei by having spiny tubercles on the dorsum and tail and small subcaudal scales. It is distinguished from H. steindachneri by the absence of a longitudinal row of keeled tubercles on the ventrolateral border of flanks; from H. echinus by lacking a double row of enlarged spines on the lateral side of the tail; from H. ansorgii by having a more robust body (versus largely dorsoventrally flattened/slender) and by having enlarged keeled tubercles on body and tail (versus tubercles relatively indistinct). It differs from H. pseudomuriceus by having small subcaudal scales (versus large, hexagonal midventral subcaudals); from H. muriceus by having a higher number of dorsal tubercle rows (14–16 versus 7–12); and from H. hecqui in its smaller size (maximum SVL 36.7 mm versus 50 mm for the unique holotype of H. hecqui ).

With respect to Angolan congeners, H. vernayi sp. nov. differs from H. longicephalus in its lower number of dorsal tubercle rows (14–16 versus 16–18) and by its much smaller maximum size (maximum SVL 36.7 versus 54.8 mm); from H. benguellensis by its lower number of precloacal pores (4–6 versus 23–33); and from H. mabouia by having a lower number of precloacal pores (4–6 versus 28–39); from H. paivae by its much smaller maximum size (maximum SVL 36.7 versus 68.4 mm) and a lower number of precloacal pores (4–6 versus 6–8); from H. nzingae in its lower number of dorsal tubercle rows (14–16 versus 16–18), higher number of dorsal tubercle rows (28–31 versus 22–27) and by its much smaller maximum size (maximum SVL 36.7 versus 51.5 mm); from H. hannahsabinae sp. nov. by in its lower number of dorsal tubercle rows (14–16 versus 16–18), higher number of dorsal tubercle rows (28–31 versus 26) and by its much smaller maximum size (maximum SVL 36.7 versus 47.4 mm).

The newly described species can be distinguished from H. bayonii , with which it has been previously confused by Ceríaco et al. (2020), by its lower number of precloacal pores (4–5 versus 6–9), by lacking a series of dark parallel dorsolateral markings and by its much more robust body and head ( Fig. 5 ).

Distribution. The species in known from low elevation (below 919 m a.s.l.) in the coastal areas of southern Angola, in Benguela Province ( Fig. 6 ).

Habitat and Natural History notes. Nothing is known regarding the natural history of this species. The habitat in Lobito, the type locality of H. vernayi sp. nov. is dominated by coastal sandy soils and xeric vegetation ( Grandvaux-Barbosa 1970).

Etymology. The specific epithet “ vernayi ”, formed in the genitive singular and is masculine, is given in honor of Arthur Stannard Vernay (1877–1960), English-born American explorer and philanthropist who funded and organized the Vernay Angolan Expedition for the American Museum of Natural History, where the type series were collected. Vernay also supported the Vernay-Lang Kalahari Expedition for the Transvaal Museum, on which the herpetologist V.F. FitzSimons (1901–1975) made important reptile discoveries. We propose the Portuguese common name of “Osga de Vernay”, and the English common name of “Vernay’s Tropical Gecko”.

Figures

FIGURE 3. Comparison between H. nzingae (paratype, AMNH 47782) and H. hannahsabinae sp. nov. (paratype, AMNH 51960) from Dande, both specimens collected in 1925. Scale 10 mm. Photos Luis M. P. Ceríaco.

FIGURE 4. Distribution map for Hemidactylus hannahsabinae sp. nov. in Angola (red triangles) and Hemidactylus nzingae (blue dots).

FIGURE 5. Holotype of Hemidactylus vernayi sp. nov. (AMNH 47770) (A), and the neotype of H. bayonii (CAS 263354) (B). Scale 10 mm. Photos Luis M. P. Ceríaco.

FIGURE 6. Distribution map for Hemidactylus vernayi sp. nov. in Angola (red triangles represent confirmed records, white triangles non-confirmed records from TM specimens), and H. bayonii (blue dots).