Bothriechis nubestris, Doan, Tiffany M., Mason, Andrew J., Castoe, Todd A., Sasa, Mahmood & Parkinson, Christopher L., 2016

Doan, Tiffany M., Mason, Andrew J., Castoe, Todd A., Sasa, Mahmood & Parkinson, Christopher L., 2016, A cryptic palm-pitviper species (Squamata: Viperidae: Bothriechis) from the Costa Rican highlands, with notes on the variation within B. nigroviridis, Zootaxa 4138 (2), pp. 271-290 : 277-281

Bothriechis nubestris new species

Talamancan Palm-Pitviper Figures 4–5 .

Bothriechis nigroviridis Peters 1859:278 . [In part.]

Holotype. UTA R- 9637 ( Campbell and Lamar, 2004: fig. 97B), an adult female, from San Isidro de El General, Province of San José, COSTA RICA; approximately 3000 m; collected in October 1973 by Peter Seigfried.

Paratypes. All from province of San José, COSTA RICA: UTA R- 2801, 2808, 2850, 7327, 7463, 9635, 9636, 10433, all from San Isidro de El General District; UCR 5727, 5728, 5758, 11151, 15420, 15423, 15424, 15432, all from San Gerardo de Dota; UCR 12356, from División, Páramo District.

Referred specimens. From province of San José, COSTA RICA: UCR 5757, from San Gerardo de Dota; UTA R- 6799, 9364, 9365, 10432, all from San Isidro de El General District; CM 145874 , 148063, 148064, LACM 154553, Cerro de la Muerte near San Gerardo; UCR 16726, Providencia; UCR 15422, 15429, Alto Palma, Parque Nacional Braulio Carrillo, Bajo la Hondura (locality possibly in error); UCR 15428, Las Nubes (locality possibly in error); UCR 3951, Naranjo, Río Naranjo; UMMZ 117734, no precise locality data. From province of Cartago: MVZ 24228. From unknown Costa Rican locality: UCR 15439. From province of Limón: UCR 22428, Talamanca, Telire, Cerro Uthyum.

Diagnosis. (1) a medium-sized slender arboreal pitviper; (2) dorsum green with heavy black mottling; (3) iris blackish; (4) superciliary scales absent; (5) interrictals 22–29; (6) supraoculars thin, usually kidney-shaped; (7) intersupraoculars 6–10; (8) partial rows or two rows of irregular scales between suboculars and supralabials; (9) infralabials 9–12; (10) first dorsals usually 21 (75.9%); (11) second dorsals usually 21 (58.6%); (12) third dorsals usually 17 (85.7%); (13) ventrals 150–160; (14) subcaudals 52–64; (15) tail prehensile.

Specimens of Bothriechis nubestris differ from B. schlegelii and B. supraciliaris by lacking superciliary scales (present in B. schlegelii and B. supraciliaris ). Bothriechis nubestris differs from all other Bothriechis species except B. nigroviridis by having green dorsal coloration with heavy black mottling and a blackish iris. Bothriechis nubestris differs from B. nigroviridis (see Table 1 for summary) by the combination of having 150–160 ventral scales (136–149 in B. nigroviridis ), thin, often kidney-shaped supraoculars with a wide intersupraocular space ( B. nigroviridis usually have wider supraoculars, never kidney-shaped, with narrow intersupraocular space), and higher average counts of interrictals, dorsals, and subcaudal scales than B. nigroviridis .

Description of holotype. An adult female; SVL 779 mm; tail length 132.2 mm, comprising 14.51% of total; head length 38.9 mm; maximum head width 23.8 mm; rostral scute broader than high (4.2 X 3.2 mm); nasal divided above and below nostril, nasal fused with first supralabial on right side; loreal 1/1, contacting canthal, upper preocular, supralacunal, prelacunal, and two prefoveals; prefoveals 6/8; subfoveals absent; postfoveals 3/4; prelacunal large, contacting third supralabial on right side, second and third supralabials on left side; sublacunals 2/ 2; postlacunal absent because supralacunal and second sublacunal in contact; preoculars 3/3, upper large, middle about half size of upper, lower small and rounded; suboculars 2/2, anterior scale long; postoculars 3/3; loreal pit large, directed anteriorly, center of pit located slightly below line drawn from center of eye to naris and approximately halfway between center of eye and naris; supralabials 11/11 (including fusion of nasal with first supralabial on right side); infralabials 10/11, first pair meet posteriorly. Mental broader than long (3.6 X 2.9 mm); three pairs of chin shields flanking mental groove, first two pairs contacting infralabials; five gulars between chin shields and preventrals; three preventrals. Internasals 3 anteriorly; canthals 2/2, anterior above nasal, posterior contacting loreal and upper preocular; 1/2 small scales between posterior canthal and supraocular; three scales between anterior canthal pair; four scales between posterior canthal pair; superciliaries absent; supraoculars narrow, approximately three times longer than broad; intersupraoculars nine; scales in parietal region small and keeled; interrictals 23. Dorsal scale rows 21-21-17; ventrals 156; cloacal entire; subcaudals 53, first divided; tail spine short, blunt, 1 ½ times as long as preceding subcaudal scale, covered by scales; tail prehensile.

Coloration in preservative. Dorsum of head and body black and pale green mottled; dorsal surface of tail less mottled, grey-green speckled with black, last third yellowish brown lightly speckled with black; postocular stripe extending to rictus, above stripe faint black longitudinal striping, below stripe yellowish with some black blotches on upper lip; ventral surface of head and body yellow, becoming more yellowish green posteriorly. Subcaudal region grey-green with black speckling fading to brown with faint black speckling near tip. Coloration in life of holotype unknown.

Variation. Dorsals were most commonly arranged in 21–21–17 (42.9% of specimens), whereas each of the following combinations were also observed: 23–23–17, 23–21–17, 21–21–15, 21–20–17, 21–19–17, 21–19–15, 19–21–17, 19–19–17, 19–17–17, and 19–17–15.

Ventral scales range 151–157 (mean = 153.7) in males and 152–160 in females (mean = 155.4). Subcaudal scales range 53–62 (mean = 58.6) in males and 52–64 (mean = 56.2) in females. Tail length comprises 14–17% (mean = 15.2%) of total length in males; tail comprises 14–16% (mean = 15.0%) of total length in females.

Head scale variation is as follows: prefoveals 4–7; subfoveals 0–1 (present in one specimen only, all others lack subfoveals); postfoveals 1–4; suboculars 1–4; postoculars 2–3; supralabials 9–11; infralabials 9–12; internasals 2–4; intercanthals 4–7; interrictals 22–29 ( Table 1 ).

Coloration in preservative varied among specimens and consisted of two rather distinct morphs, with few specimens showing intermediate coloration. Twenty-six percent of the specimens had nearly identical coloration to the holotype. Sixty percent of the specimens displayed a darker color morph with dorsal green being replaced by dark grey and the yellowish venter being replaced by beige, fading to grey-green on the tail. The same ventral pattern is present is both morphs but the yellow is replaced by beige in the darker morph. In two specimens, the dorsum is the “darker morph” but the venter is like the holotype’s with yellow. Recently-born juveniles had brown and black dorsums with beige-brown venters and the tail tips were completely brownish yellow. Coloration in life of three known specimens is nearly identical to the holotype coloration in preservative.

Hemipenes. Paratype UCR 11151 had fully everted hemipenes. The total length of the right hemipenis was equal to the length of the first five subcaudal scales. The two lobes of the organ bifurcate at an approximate length of two subcaudals and the sulcus spermaticus divides at a distance of approximately ½ the length of a subcaudal. The base of the organ is spinous, whereas the distal portion is covered in calyces. Spines are dense and evenly dispersed; some spines are quite large. Calyces begin approximately 1 ½ subcaudal scale lengths from the tip of the organ.

Distribution and natural history. Bothriechis nubestris is known from the northern and central portions of the Cordillera de Talamanca of Costa Rica in the provinces of San José, Cartago, and Limón (see Fig. 6 ). Three specimens (UCR 15422, 15428, 15429) have locality data that indicate they are from the Cordillera Central, but they were snakes donated by locals to the Instituto Clodomiro Picado and it is possible that the locality data were recorded in error. We exclude these localities from consideration here, but acknowledge that if these localities are correct, the species also occurs in the Cordillera Central. The species has been recorded from 2400 m on Cerro de la Muerte to over 3000 m in San Gerardo de Dota. Bothriechis nubestris is an arboreal species usually found in the transition zone between cloud forest and montane rainforest.

Etymology. The specific epithet means ‘belonging to the clouds’. It is derived from the Latin noun nubes, –is, meaning cloud, and the Latin suffix –estris, meaning belonging to. This name alludes to the fact that this species inhabits cloud forests. The common name Talamancan Palm-Pitviper refers to its range in the Cordillera de Talamanca.

Figures

FIGURE 4. Photographs of Bothriechis nubestris sp. n. in life. Top photographer: John Tashjian; middle and bottom photographer Wayne van Devender.

FIGURE 5. Dorsal and lateral views of the head of male paratype UCR 11151 from San Gerardo, Costa Rica. Scale bar = 20 mm. The diagnostic kidney-shaped supraoculars and partial scale rows between the supralabials and suboculars are highlighted.

FIGURE 6. Topographical map indicating localities of Bothriechis nigroviridis (black symbols) and B. nubestris sp. n. (blue symbols) used in this study: 72 used in morphological analyses (circles), 21 used in genetic analyses (squares), and 3 used in both (triangles).

Tables

TABLE 1. Comparison of morphological characters of Bothriechis nigroviridis (n = 41) and B. nubestris (n = 27) (some specimens could not have all characters scored because of damage). The format is Range; Mode; Mean.

Character	B. nigroviridis	B. nubestris
Dorsal scales--First Third	17–21; 19; 18.90	19–23; 21; 20.93
Dorsal scales--Midbody	17–21; 19; 18.90	17–23; 21; 20.21
Dorsal scales--Last Third	15–19; 15; 15.82	15–17; 17; 16.71
Ventral scales	136–149; 141; 142.73	150–160; 155; 154.64
Subcaudal scales	48–64; 50; 52.79	52–64; 59; 57.41
Supralabials	9–11; 10; 9.76	9–11; 10; 9.62
Intersupraoculars	3–10; 6; 6.34	6–10; 8; 7.83
Interrictals	19–26; 22; 21.90	22–29; 24; 25.07