Sibon canopy, Arteaga & Batista, 2023

Arteaga, Alejandro & Batista, Abel, 2023, A consolidated phylogeny of snail-eating snakes (Serpentes, Dipsadini), with the description of five new species from Colombia, Ecuador, and Panama, ZooKeys 1143, pp. 1-49 : 1

Sibon canopy sp. nov.

Figs 2c , 4a , 5b , 7 Proposed standard English name: Canopy Snail-eating Snake Proposed standard Spanish name: Culebra caracolera de dosel

Type material.

Holotype: MHCH 3110 (Figs 5b , 7 ), adult female collected by Abel Batista on 8 August 2016 at Cerro Gaital, La Pintada, Coclé province, Panama (8.70874, -80.42411; 543 m a.s.l.).

Paratypes: MHCH 1067, SMF 88713-14, juveniles collected by Johannes Köhler, Abel Batista, and Marcos Ponce on 17 January 2007 at Casa de Ancón, Sendero el Pianista, Bocas del Toro province, Panama (8.87142, -82.41594; 1005 m a.s.l.). MHCH 220, juvenile female collected by Abel Batista and Marcos Ponce on March 2002 at Camino al Río Culebra, Bocas del Toro province, Panama (8.90772, -82.39115; 698 m a.s.l.). SMF 85077, adult female collected by Gunther Köhler, Abel Batista, Marcos Ponce, and Javier Sunyer on 17 January 2006 at Reserva Forestal La Fortuna, Comarca Ngäbe-Buglé, Panama (8.77763, -82.20916; 1030 m a.s.l.). SMF 89596, adult female collected by Leonhard Stadler and Nadim Hamad on 5 August 2008 at Cerro Mariposa, Veraguas province, Panama (8.52488, -81.13275; 679 m a.s.l.). SMF 90023, adult female collected by Arcadio Carrizo on 27 June 2008 at Cerro Negro, Veraguas province, Panama (8.56901, -81.09894; 680 m a.s.l.). SMF 91578, adult female collected by Sebastian Lotzkat and Andreas Hertz on 17 July 2010 at Río Changena, Bocas del Toro province, Panama (8.97851, -82.69005; 1641 m a.s.l.). SMF 86411, juvenile collected by Abel Batista and Marcos Ponce on 10 February 2006 at Sendero El Pianista, Bocas del Toro province, Panama (8.87141, -82.41594; 1005 m a.s.l.). SMF 90208, juvenile collected by Joe-Felix Bienentreu and Frank Hauenschild on 25 October 2009 at Cerro Guayabo, Chiriquí province, Panama (8.75531, -82.25431; 1247 m a.s.l.). MHCH 2363-64, males collected by Sebastian Lotzkat and Andreas Hertz between 29 October 2009 and 11 June 2010 at Cabeceras del Río Chiriquí Mali, Comarca Ngäbe-Buglé, Panama (8.78906, -82.21547; 1080 m a.s.l.). MHCH 2365, juvenile male collected by Sebastian Lotzkat and Andreas Hertz on 7 August 2010 at Cerro Mariposa, Veraguas province, Panama (8.50815, -81.12104; 899 m a.s.l.). SMF 85078, adult male collected by Gunther Köhler, Abel Batista, Marcos Ponce, and Javier Sunyer on 19 January 2006 at Reserva Forestal La Fortuna, Comarca Ngäbe-Buglé, Panama (8.77763, -82.20916; 1030 m a.s.l.). SMF 88715, adult male collected by Sebastian Lotzkat and Andreas Hertz on 14 May 2008 at Trail to Rio Hornito, Chiriquí province, Panama (8.67385, -82.21845; 1320 m a.s.l.). SMF 89597, adult male collected by Leonhard Stadler and Nadim Hamad on 6 August 2008 at Cerro Mariposa, Veraguas province, Panama (8.51463, -81.11927; 1003 m a.s.l.). SMF 89786, adult male collected by Sebastian Lotzkat and Andreas Hertz on 1 April 2009 at Cerro Negro, Veraguas province, Panama (8.56901, -81.09894; 900 m a.s.l.). SMF 90024, adult male collected by Arcadio Carrizo on 29 July 2008 at Cerro Negro, Veraguas province, Panama (8.57697, -81.09705; 1085 m a.s.l.). SMF 90207, adult male collected by Sebastian Lotzkat and Andreas Hertz on 29 October 2009 at Cabeceras del Río Chiriquí Mali, Comarca Ngäbe-Buglé, Panama (8.78906, -82.21547; 1054 m a.s.l.). SMF 91579, adult male collected by Sebastian Lotzkat and Andreas Hertz on 11 June 2010 at Cabeceras del Río Chiriquí Mali, Comarca Ngäbe-Buglé, Panama (8.78906, -82.21547; 1054 m a.s.l.). SMF 91580, adult male collected by Sebastian Lotzkat and Andreas Hertz on 24 June 2010 at Bosque Guayabito, Comarca Ngäbe-Buglé, Panama (8.54939, -81.48467; 1510 m a.s.l.).

Diagnosis.

Sibon canopy sp. nov. is placed in the genus Sibon based on phylogenetic evidence (Fig. 1a ) and on having the penultimate supralabial conspicuously higher than all other supralabials. The species is diagnosed based on the following combination of characters: (1) 15/15/15 smooth dorsals with enlarged vertebral row (1.4 × as wide as adjacent rows); (2) loreal and prefrontal in contact with orbit; (3) 7-8 supralabials with, usually, 4th, 5th, and occasionally 6th contacting orbit; (4) usually 7-8 infralabials with 2nd-6th in contact with chinshields, first pair of infralabials not in contact behind symphysial due to presence of a postmental; (5) 180-189 ventrals in males, 170-185 in females; (6) 113-130 divided subcaudals in males, 107-124 in females; (7) dorsal background color olive with maroon bands (1-2 dorsal scales long mid-dorsally and 3-5 dorsal scales long on the lower flanks) and a reddish tint along the vertebral line (Fig. 2c ), ventral surfaces white with encroachment from the dorsal maroon blotches, dorsal aspect of head composed of broad irregular maroon to blackish blotches interspersed with olive to red blotches (Fig. 5b ), throat white with brownish blotches, iris dark reddish brown; (8) 336-427 mm SVL in males, 318-357 mm in females; (9) 160-221 mm TL in males, 157-185 mm in females.

Comparisons.

Sibon canopy sp. nov. is compared to other species of Sibon previously subsumed under S. annulatus sensu lato (differences summarized in Table 2 ). From S. annulatus sensu stricto, the new species differs in having a single postmental scale, olive spaces among dorsal bands enclosing maroon blotches (Figs 2c , 4a ), and by having small irregular (rather than broad and symmetrical) markings on the dorsal surface of the head (Fig. 5 ). Sibon canopy sp. nov. differs from S. irmelindicaprioae sp. nov. by having one postmental scale (instead of two), a lower number of infralabials (6-10 vs. 8-10), a lower number of ventrals in males (180-189 vs. 187-196), a different pattern on the dorsal surface of the head (Fig. 5 ), and by having maroon spots enclosed in the dorsal olive interspaces (Figs 2 , 4 ). Sibon canopy sp. nov. differs from S. marleyae sp. nov. by having one postmental scale (instead of two), olive spaces among dorsal bands enclosing maroon blotches (Figs 2 , 4 ), and by having irregular (rather than symmetrical) markings on the dorsal surface of the head (Fig. 5 ).

Description of holotype.

Adult female, SVL 321 mm, tail length 157 mm (48% SVL); head length 15.4 mm (4.7% SVL) from tip of snout to commissure of mouth; head width 8.0 mm (76% head length) taken at broadest point; snout-orbit distance 3.3 mm; head distinct from neck; snout short, blunt in dorsal outline and rounded in profile; rostral 2.1 mm wide, higher than broad; internasals 1.6 mm wide, broader than long; prefrontals 1.9 mm wide, longer than broad, entering orbit; supraocular 3.7 mm long, longer than broad; frontal 3.2 mm long, pentagonal and with a straight anterior border, in contact with prefrontals, supraoculars, and parietals; parietals 5.2 mm long, longer than broad; nasal divided, in contact with first three supralabials, loreal, prefrontal, internasal, and rostral; loreal 1.7 mm long, longer than high, entering the orbit; eye diameter 3.0 mm; pupil semi-elliptical; no preocular; two postoculars; temporals 1+2; eight supralabials with 5th and 6th contacting orbit on the right side, seven supralabials with 4th and 5th contacting orbit on the left side; symphysial in contact with chinshields; nine infralabials with 2nd-5th contacting chinshields; two pair of chinshields longer than wide; dorsal scales in 15/15/15 rows, smooth, without apical pits; 172 ventrals; 93+ divided subcaudals; cloacal plate entire.

Natural history.

Lotzkat (2014) found specimens of Sibon canopy sp. nov. foraging at night on vegetation 50-300 cm above the ground in old-growth to moderately disturbed evergreen foothill/montane forests. At Cerro Gaital, Coclé province, we found two specimens moving on mossy branches and moist leaves 40-220 cm above the ground in primary forest during a drizzle. Ray et al. (2012) found this species to be more common in forest and along streams rather than around ponds. Only one individual (a juvenile) was seen crawling along a stream bed. Ray et al. (2012) found oligochaete and mollusk remains in fecal samples of 37 individuals of S. canopy sp. nov. from El Copé and Altos del María, Panama. They also observed an individual feeding on a snail at El Copé.

Distribution.

Sibon canopy sp. nov. is known from 25 localities (listed in Suppl. material 2) in both the Atlantic and Pacific slopes of the Cordillera Central in western Panama, with a population on the slopes of El Valle Volcano. The species occurs over an estimated area of 8,089 km2 and has been recorded at elevations 543-1641 m above sea level (Fig. 6 ).

Etymology.

The specific epithet Sibon canopy is used as a noun in apposition and honors the Canopy Family system of reserves, particularly its Canopy Lodge in Valle de Antón, Coclé province, Panama, where the new species occurs. Though best known for its world-class eco-tourism focused on birds, the Canopy Family also protects habitat that is critical for dozens of poorly studied Panamanian snakes such as S. canopy sp. nov. and S. irmelindicaprioae sp. nov. The project was founded in 1994 by Raúl Arias de Para and Denise Barakat de Arias, two champions of Panamanian conservation who are deeply intertwined with the Political history of the country. In 2019, the Canopy Family invited us to explore their system of reserves in order to discover their herpetofauna. As a result of this invitation, both S. canopy sp. nov. and a new species of Dipsas were discovered.

Conservation status.

We consider Sibon canopy sp. nov. to be included in the Near Threatened category following IUCN Red List criteria ( IUCN 2001) because, although the species’ estimated extent of occurrence is less than 10,000 km2 and nearly 40% of this area has already been deforested (Fig. 6 ; CATHALAC 2011), the species occurs in at least four major national parks ( Lotzkat 2014) and satellite images show that there is forest connectivity between populations. At Parque Nacional G. D. Omar Torríjos Herrera, the occurrence rates of S. canopy sp. nov. have actually increased by a factor of three in the period between 2006 and 2012 ( Zipkin et al. 2020). However, the body condition of the individuals in this locality declined following the collapse of amphibian populations due to chytridiomycosis ( Zipkin et al. 2020). The status and trend of other populations should be evaluated carefully given that S. canopy sp. nov. is endemic to Panama (but see Discussion) and probably highly dependent on old-growth forests.

Figures

Figure 1. Phylogenetic relationships within Dipsadini inferred using a Bayesian inference and derived from analysis of DNA gene fragments 12 S, 16 S, COI, CYTB, ND 4, DNAH 3, and NT 3. Support values on intra-specific branches are not shown for clarity. Voucher numbers for sequences are indicated for each terminal. Black dots indicate clades with posterior probability values from 95 - 100 %. Grey dots indicate values from 70 - 94 %. White dots indicate values from 50 - 69 % (values <50 % not shown). Colored clades correspond to the species' distribution presented in the maps. New or redefined species are indicated in bold type.

Figure 2. Photographs of some species of Sibon in life a S. irmelindicaprioae sp. nov. MHCH 3269 from Chucanti Reserve, Darien province, Panama b S. irmelindicaprioae sp. nov. from Morromico Reserve, Choco department, Colombia c S. canopy sp. nov. from Cerro Gaital, Cocle province, Panama d, e S. annulatus from Centro Manu, Limon province, Costa Rica f S. ayerbeorum ZSFQ 5066 from Canande Biological Reserve, Esmeraldas Province, Ecuador g S. marleyae sp. nov. holotype ZSFQ 5065 from Verdecanande, Esmeraldas Province, Ecuador h S. marleyae sp. nov. ZSFQ 5068 from Verdecanande, Esmeraldas Province, Ecuador i S. marleyae sp. nov. neonate from Verdecanande, Esmeraldas Province, Ecuador.

Figure 4. Photographs of some species of Sibon and Dipsas in life a S. canopy sp. nov. from El Valle de Anton, Cocle province, Panama b S. irmelindicaprioae sp. nov. holotype MHCH 3143 from Puerto Indio, Darien province, Panama c S. marleyae sp. nov. from Verdecanande, Esmeraldas Province, Ecuador d S. vieirai sp. nov. from Mashpi Amagusa Reserve, Pichincha province, Ecuador e Dipsas sp. from Cerro Gaital, Cocle province, Panama f D. welborni sp. nov. ZSFQ 5060 from Via a Nuevo Paraiso, Zamora Chinchipe province, Ecuador.

Figure 5. Differences in head morphology between species of Sibon previously subsumed under S. annulatus a S. annulatus MHCH 1982 from Bonyic, Bocas del Toro province, Panama b S. canopy sp. nov. holotype MHCH 3110 from Cerro Gaital, Cocle province, Panama c S. irmelindicaprioae sp. nov. MHCH 3120 from Pirre, Darien province, Panama d S. marleyae sp. nov. holotype ZSFQ 5065 from Verdecanande, Esmeraldas Province, Ecuador.

Figure 6. Distribution of species of Sibon previously subsumed under S. annulatus. Black symbols represent type localities; white symbols other localities listed in Suppl. material 2. Colored areas show the extent of suitable environmental conditions for each species.

Figure 7. Adult female holotype of Sibon canopy sp. nov. MHCH 3110 in a dorsal and b ventral view.