Chatogekko, 2011

Gamble, Tony, Daza, Juan D., Colli, Guarino R., Vitt, Laurie J. & Bauer, Aaron M., 2011, A new genus of miniaturized and pug-nosed gecko from South America (Sphaerodactylidae: Gekkota), Zoological Journal of the Linnean Society 163 (4), pp. 1244-1266 : 1250-1252

CHATOGEKKO GAMBLE, DAZA, COLLI, VITT AND BAUER , GEN. NOV. (FIGS 5, 6)

Type species: Sphaerodactylus amazonicus ( Andersson, 1918)

Diagnosis and description: A miniaturized species complex of diurnal sphaerodactyl geckos. Mean SVL 21 ± 1.8 mm, N = 41. Snout shortened. Pupil round. Body cylindrical. Dorsal scales keeled. Claws enclosed in ungual sheath consisting of four scales. Posterior edge of premaxilla contacts medial process of frontal bone. Posterior edge of ascending nasal process bifurcated. Palatine longer than vomer. Postparietal process of parietal in contact with supraoccipital and otooccipital, but not squamosal. Reduced paroccipital process located dorsally to fenestra ovalis.

Chatogekko is distinguished from all gekkotans by the following unique combination of characters: (1) between two and four loreal scales (ls, Fig. 4A , also present in some Sphaerodactylus ); (2) claws enclosed in an ungual sheath consisting of four scales ( Parker, 1926; Vanzolini, 1957; Avila-Pires, 1995): inner supero-lateral (isl, Fig. 4B ), outer supero-lateral (osl, Fig. 4B ), inner infero-lateral (iil, Fig. 4C ), and outer infero-lateral (oil, Fig. 4C ) (ventrolaterals sensu Kluge, 1995); (3, Fig. 4D ) keeled scales on dorsal body surface ( Vanzolini, 1957; Avila-Pires, 1995), also present in some Sphaerodactylus ; (4, Fig. 5A) bony external nares large and entering or approaching contact between prefrontal and nasals (as a consequence of extensive overlapping contact of maxilla and prefrontal); (5, Fig. 5A) posterior edge of premaxilla (i.e. the ascending nasal process) contacts medial process of frontal bone ( Daza et al., 2008); (6, Fig. 5A) posterior edge of ascending nasal process bifurcated; (7, Fig. 5A) internasal contact absent; (8, Fig. 5A) jugal bone vestigial and limited to tip of maxilla; (9, Fig. 5A) postparietal process of parietal contacting supraoccipital and otooccipital, but not squamosal; (10, Fig. 5A) paroccipital process of otooccipital not visible in dorsal view; (11, Fig. 5B) paroccipital process very reduced and located dorsally to fenestra ovalis (instead of posterior as in other gekkotans) and not participating in quadrate articulation (paroccipital abutting); (12, Fig. 5B) palatine exceeds vomer substantially in length; (13, Fig. 10 ) duplicipalatinate condition; (14) a 3-bp deletion in coding region of exon 8 (in Gallus ) of RBMX; and (15) a 3-bp deletion in coding region of exon 13 (in Gallus ) of PTPN12.

Distribution: Central and eastern Amazonia, including the Brazilian states of Acre, Amazonas, Rondônia, Mato Grosso, Roraima, Pará, and Amapá; French Guiana; Guyana; Suriname; the Venezuelan state of Amazonas; and northern Bolivia ( Gasc, 1990; Avila-Pires, 1995; Langstroth, 2005; Geurgas & Rodrigues, 2010).

Natural history: Chatogekko lives in the leaf litter in a variety of undisturbed lowland forested habitats ( Vitt et al., 2005). These geckos are active throughout the day although they do not bask ( Hoogmoed, 1973). Diet is made up of small insects including springtails, mites and ticks, termites, homopterans, and larval insects ( Hoogmoed, 1973; Ramos, 1981; Vitt et al., 2005). Females lay one egg per clutch and can produce several clutches during the year ( Hoogmoed, 1973; Gasc, 1990). Chatogekko can be locally very abundant but appears to be negatively affected by forest fragmentation ( Carvalho et al., 2008).

Etymology: A composite word from the Spanish and Portuguese ‘Chato’, derived from the Greek ‘Platus’, meaning ‘flat’ and referring to its pug-nosed snout; and gekko from the Malay ‘gekoq’, onomatopoeic of the call of the species Gekko gecko and the common name to all limbed gekkotans. A Sri Lankan origin for the word gekko, derived from the Sinhalese word ‘gego’, is also possible ( de Silva & Bauer, 2008 ). The name is masculine.

Species composition: Chatogekko amazonicus ( Andersson, 1918) . In addition, the names C. zernyi ( Wettstein, 1928) and C. guimaraesi ( Vanzolini, 1957) are available for populations from eastern Amazonia and southwest Amazon, respectively. See Discussion for details.

Figures

Figure 4. Chatogekko amazonicus specimens. A, lateral view of the head showing 2–4 loreal scales (ls); B, dorsal view of the left hand showing the inner supero-lateral and outer supero-lateral (isl and osl, Fig. 5B); C, ventral view of the left hand showing the inner infero-lateral and outer infero-lateral (iil and oil, Fig. 5C); and D, keeled scales along the dorsal surface of the body. A–C, USNM 288775; D, MZUSP 91394. Scale bar = 1mm.

Figure 10. Palatal view of cleared and stained Chatogekko amazonicus specimen from Guyana (AMNH-R 132039) showing the secondary palate formed on the palatine. Abbreviations: bp, basipterygoid; bpcp, cartilaginous pad of the basipterygoid process; cc, choanal canal; ec, ectochoanal cartilage; fe, fenestra exochoanalis; pal, palatine; palvp, ventral process of the palatine; pmx-v f, premaxillary–vomer fenestra; pt, pterygoid; sof, suborbital fenestra; v, vomer; vp, vomerine process of palatine. Scale bar = 1 mm.