Dipsas georgejetti, Arteaga, Alejandro, Salazar-Valenzuela, David, Mebert, Konrad, Penafiel, Nicolas, Aguiar, Gabriela, Sa ́ nchez-Nivicela, Juan C., Pyron, R. Alexander, Colston, Timothy J., Cisneros-Heredia, Diego F., Yanez-Munoz, Mario H., Venegas, Pablo J., Guayasamin, Juan M. & Torres-Carvajal, Omar, 2018

Arteaga, Alejandro, Salazar-Valenzuela, David, Mebert, Konrad, Penafiel, Nicolas, Aguiar, Gabriela, Sa ́ nchez-Nivicela, Juan C., Pyron, R. Alexander, Colston, Timothy J., Cisneros-Heredia, Diego F., Yanez-Munoz, Mario H., Venegas, Pablo J., Guayasamin, Juan M. & Torres-Carvajal, Omar, 2018, Systematics of South American snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Ecuador and Peru, ZooKeys 766, pp. 79-147 : 92-93

Dipsas georgejetti sp. n. Figs 11, 12

Proposed standard English name.

George Jett’s Snail-Eater

Proposed standard Spanish name.

Caracolera de George Jett

Holotype.

MZUTI 5411 (Figs 11, 12), adult male collected by Melissa Costales on August 31, 2017 at Cabuyal, province of Manabí, Ecuador (S0.19698, W80.29059; 15 m).

Paratypes.

DHMECN 11639, adult male collected by Jacinto Bravo in 2014 at Montecristi, province of Manabí, Ecuador (S1.04694, W80.65766; 136 m). DHMECN 11646, adult male collected by Félix Almeida in 2014 at Rocafuerte, province of Manabí, Ecuador (S0.92371, W80.45212; 19 m). MZUA.RE.0121 and MZUA.RE.0122, adult female and adult male, respectively, collected by Juan Carlos Sánchez-Nivicela at El Aromo, province of Manabí, Ecuador (S1.04665, W80.83227; 295 m). QCAZ 10589, adult male collected at El Aromo, province of Manabí, Ecuador (S1.04665, W80.83227; 295 m). QCAZ 9125, adult male collected at Cerro Blanco, province of Guayas, Ecuador (S2.17465, W80.02135; 147 m). USNM 142595, juvenile of undetermined sex collected on December 1959 at 10 mi N of Guayaquil, province of Guayas (S1.96418, W79.87988; 5 m). ZSFQ D606, juvenile male collected by Diego F. Cisneros-Heredia at the foothills of Cerro La Mocora, Parque Nacional Machalilla, province of Manabí, Ecuador (S1.59817, W80.75431; 308 m).

Diagnosis.

Dipsas georgejetti is placed in the genus Dipsas based on phylogenetic evidence (Fig. 3) and the absence of a labial that is noticeably higher than other labials and in contact with the postocular, primary and secondary temporals. The species differs from all described species of Dipsas based on the following combination of characters: (1) 15/15/15 smooth dorsals with a slightly enlarged vertebral row (1-1.4 times as wide as adjacent rows); (2) loreal and prefrontal in contact with orbit; (3) 7 supralabials with 4th and 5th (3 th– 5th in DHMECN 11646) contacting orbit; (4) no infralabials in contact behind symphysial; (5) 172-180 ventrals in males, 177 in one female; (6) 69-86 divided subcaudals in males, 58 in one female; (7) dorsal ground color light sandy brown with a pattern of 53-61 drab to brown black-edged middorsal blotches that are wider (6-7 vertebral scales long) and solid down to the edges of the ventrals on the first one third of the body, but becoming narrower (1-3 vertebral scales long) and broken up laterally towards the tail; interspaces finely speckled with brown pigment; ground color of the head light sandy brown with bold dark brown to black irregular blotches scattered on head plates and edging supralabials; ventral surfaces sandy brown with fine black speckling; iris sandy brown with dense dark brown speckling; (8) 270-711 mm SVL in males, 856 mm in one female; (9) 87-170 mm TL in males, 150 mm in one female.

Comparisons.

Dipsas georgejetti is most similar to D. oswaldobaezi , D. williamsi , D. oligozonata , and D. vagrans , in that order, all of which were previously included in the genus Sibynomorphus . From D. oswaldobaezi (Figs 13, 14) and D. williamsi , it differs in having 7 supralabials with 4th and 5th bordering the eye (instead of 6 with 3rd and 4th bordering the eye). It further differs from D. williamsi in having the first supralabial not in contact with prefrontal (vs. in broad contact in D. williamsi ). From D. oligozonata (Fig. 1o) and D. vagrans , it differs in having more than 160 ventrals. Dipsas georgejetti further differs from D. oligozonata in having distinct bold crossbands at least middorsally along the whole length of the body, instead of being present only on the anterior half of the body. Genetic divergence in a 529 bp long fragment of the mitochondrial Cytb gene between D. georgejetti and D. oswaldobaezi is 8.3%, whereas intraspecific distances are less than 0.4% in D. georgejetti . For the same fragment, the distance between D. georgejetti and D. williamsi is 7.8-7.9%.

Description of holotype.

Adult male, SVL 315 mm, TL 87 mm (28% SVL); head length 13.6 mm (4% SVL) from tip of snout to commissure of mouth; head width 8.4 mm (62% head length) taken at broadest point; snout-orbit distance 3.5 mm; head distinct from neck; snout short, blunt in dorsal and lateral outline; rostral 2.0 mm wide, broader than high; internasals 1.7 mm wide, broader than long; prefrontals 2.5 mm wide, longer than broad and contacting orbit; supraocular 3.4 mm long, longer than broad; frontal 3.3 mm long, pentagonal, in contact with prefrontals, supraoculars, and parietals; parietals 5.5 mm long, longer than broad; nasal divided, in contact with first two supralabials, loreal, prefrontal, internasal, and rostral; loreal 1.7 mm long, slightly higher than long, entering orbit; eye diameter 2.8 mm; pupil semi-elliptical; no preocular; two postoculars; temporals 2+2; seven supralabials, 4th and 5th contacting orbit; symphysial in contact with first pair of chinshields; nine infralabials, 1-6 contacting chinshields; anterior pair of chinshields longer than broad, posterior pair broader than long; dorsal scales in 15/15/15 rows, smooth, without apical pits; 178 ventrals; 69 divided subcaudals; cloacal plate single.

Natural history.

The holotype was active during a dry night after a sunny day. It was perched on tangled vegetation 130 cm above the ground in dry shrubland besides recently cleared pasture. MZUA.RE0121 and MZUA.RE0122 were found actively moving at night between the branches 80-200 cm above the ground. ZSFQ D606 was found active during daytime after bulldozers opened a track in old-growth forest.

Distribution.

Deciduous and semideciduous forests along the central Pacific coast in Ecuador in the provinces of Manabí and Guayas, at elevations between 5 and 317 m (Fig. 5).

Etymology.

The specific name georgejetti honors George Jett, who has been a long-time donor to Rainforest Trust and has supported the reserves of Fundación Jocotoco in Ecuador. He is an international traveler with a passion for reptiles, amphibians, and birds.

Conservation status.

We consider Dipsas georgejetti to be Vulnerable following the IUCN criteria A1c,B1a,b(iii, iv) (IUCN 2001) because its extent of occurrence is estimated to be 10,193 km2, it is known only from 9 localities effectively corresponding to 4 patches of forest lacking connectivity between them, and its habitat is severely fragmented and declining in extent and quality due to deforestation. At the type locality, D. georgejetti was found in a patch of deciduous forest of 13 km2 that was being cleared to accommodate cattle pastures. One of the localities, 15 km N of Guayaquil, where D. georgejetti was collected in 1959, is now completely deforested, which suggests that this arboreal species is no longer present there.