Dipsas bobridgelyi, 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 : 89-92

Dipsas bobridgelyi sp. n. Figs 1c, 9, 10

Proposed standard English name.

Bob Ridgely’s Snail-Eater

Proposed standard Spanish name.

Caracolera de Bob Ridgely

Holotype.

MZUTI 5417 (Figs 9, 10), adult male collected by Matthijs Hollanders on August 01, 2017 at Reserva Buenaventura, province of El Oro, Ecuador (S3.65467, W77.76794; 524 m).

Paratypes.

DHMECN 11527, adult female collected by Juan Carlos Sánchez-Nivicela, Karem López, Verónica Urgilés, Bruno Timbe, Elvis Celi and Valentina Posse at Remolino, province of El Oro, Ecuador (S3.56551, W79.91948; 229 m). MZUTI 3266, adult female collected by Lucas Bustamante on October 06, 2013. MZUTI 5414, adult male collected by Matthijs Hollanders and Paulina Romero on June 08, 2017. QCAZ 1706, adult male collected by Fernando Ayala, Steven Poe, and Chris Anderson on March 03, 1994 at Ponce Enríquez, province of Azuay, Ecuador (S3.06547, W79.74358; 39 m).

Diagnosis.

Dipsas bobridgelyi 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 enlarged vertebral row (2.1-2.2 times as wide as adjacent rows); (2) loreal and prefrontal in contact with orbit; (3) 9 supralabials with 4th and 5th contacting orbit; (4) one pair of infralabials in contact behind symphysial; (5) 180-201 ventrals in males, 178-184 in females; (6) 95-117 divided subcaudals in males, 96-98 in females; (7) dorsal and ventral color made up of 30-35 bold black body rings (up to 7-12 vertebral scales long) separated from each other by narrow (up to 3-4 vertebral scales long) dingy white interspaces; dorsal aspect of interspaces heavily speckled with rusty and black pigment; ventral surfaces lacking speckling; ground color of head dingy white with various degrees of scattered black pigment that coalesce on the top of the head, and various degrees of rusty speckling concentrated on the snout, nape and sides of the head; iris rich dark brown; (8) 372-478 mm SVL in males, 286-404 mm in females; (9) 158-212 mm TL in males, 117-158 mm in females.

Comparisons.

Dipsas bobridgelyi is most similar to D. gracilis , from which it differs in coloration. In D. gracilis (Figs 1h, i), the black rings are up to 10-16 vertebral scales long and the interspaces are up to 5-7 scales long, whereas in D. bobridgelyi the black rings and interspaces are shorter, up to 8-9 and 3-4 vertebral scales long, respectively. In D. gracilis , the head plates are either completely black or black scattered with reddish brown, whereas in D. bobridgelyi the head plates are heavily stippled with white and tan pigment, especially on the prefrontals and internasals. In all known specimens of D. bobridgelyi , the ground color of the interspaces is white with contrasting reddish-tan pigment in the center, whereas in D. gracilis the ground color of the light interspac es on body and tail is either completely light brown or light reddish white, gradually becoming reddish brown towards the center. Finally, the nape and temporal region of the head in D. gracilis are either immaculate light reddish brown or marked with bold black speckles, whereas in D. bobridgelyi they are an irregular mix of fine speckling of white, rusty, and black pigments. Genetic divergence in a 689 bp long fragment of the mitochondrial Cytb gene between D. bobridgelyi and D. gracilis is 8.7-9.0%, whereas intraspecific distances are less than 0.3% in both species.

Description of holotype.

Adult male, SVL 372 mm, tail length 158 mm (43% SVL); head length 15.1 mm (4% SVL) from tip of snout to commissure of mouth; head width 8.1 mm (54% head length) taken at broadest point; snout-orbit distance 4.3 mm; head distinct from neck; snout short, blunt in dorsal and lateral outline; rostral 2.4 mm wide, broader than high; internasals 2.3 mm wide, broader than long; prefrontals 2.5 mm wide, longer than broad and contacting orbit; supraocular 3.2 mm long, longer than broad; frontal 3.9 mm long, hexagonal, in contact with prefrontals, supraoculars, and parietals; parietals 4.7 mm long, longer than broad; nasal divided, in contact with first three supralabials, loreal, prefrontal, internasal, and rostral; loreal 1.8 mm long, slightly higher than long, entering the orbit; eye diameter 2.7 mm; pupil semi-elliptical; no preocular; two postoculars; temporals 2+3; nine supralabials, 4th and 5th contacting orbit; symphysial separated from chinshields by the first pair of infralabials; 13 infralabials, 1-7 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; 182 ventrals; 101 divided subcaudals; cloacal plate single.

Natural history.

Individuals of Dipsas bobridgelyi have been found active at night (19h00-23h26) on arboreal vegetation 100-250 cm above the ground in secondary semi-deciduous foothill forest. MZUTI 5414 was found feeding on a snail.

Distribution.

Foothills of the southwestern Ecuadorian Andes in the provinces of Azuay and El Oro, and northwestern Peruvian Andes in the department of Tumbes, at elevations between 39 and 572 m (Fig. 4).

Etymology.

This species is named in honor of Dr. Robert “Bob” S. Ridgely, a leading ornithologist and distinguished conservationist who has dedicated almost 50 years of his life to the study and conservation of birds and biodiversity across Latin America. Bob is the President of Rainforest Trust and for the past twenty years has been a major driver of conservation in Ecuador through Fundación Jocotoco, which he helped establish twenty years ago. In 1980, Bob visited the type locality of Dipsas bobridgelyi (Buenaventura, meaning "good fortune"), now known to be a key area for the conservation of biodiversity. Bob embarked on conservation and worked diligently to raise funds through Rainforest Trust for the past 18 years to purchase private properties and establish what is now the Reserva Buenaventura of Fundación Jocotoco.

Conservation status.

We consider Dipsas bobridgelyi to be Endangered following the IUCN criteria B1a,b(i,iii) (IUCN 2001) because its extent of occurrence is estimated to be less than 5,000 km2, it is known only from 4 patches of forest lacking connectivity between them, and its habitat is severely fragmented and declining in extent and quality due to deforestation. Furthermore, only two of the localities (Buenaventura reserve and Reserva Nacional de Tumbes) where D. bobridgelyi occurs are currently protected.

Remarks.

Cadle (2005) and Harvey (2008) examined MUSM 17589 from Tumbes department, Peru, and concluded that it was Dipsas gracilis . Although we did not examine this specimen, we believe that it corresponds to D. bobridgelyi based on Cadle’s (2005) color description (i.e., head white with many irregular black markings on the top and sides).