Bothriechis rahimi, Arteaga & Pyron & Batista & Vieira & Meneses Pelayo & Smith & Barrio Amorós & Koch & Agne & Valencia & Bustamante & Harris, 2024

Arteaga, Alejandro, Pyron, R. Alexander, Batista, Abel, Vieira, Jose, Meneses Pelayo, Elson, Smith, Eric N., Barrio Amoros, Cesar L., Koch, Claudia, Agne, Stefanie, Valencia, Jorge H., Bustamante, Lucas & Harris, Kyle J., 2024, Systematic revision of the Eyelash Palm-Pitviper Bothriechis schlegelii (Serpentes, Viperidae), with the description of five new species and revalidation of three, Evolutionary Systematics 8 (1), pp. 15-64 : 15

Bothriechis rahimi sp. nov.

Figs 25 , 26

Type material.

Holotype: ZSFQ 5055 (18), adult female collected on January 1, 2017 at Tundaloma Lodge, Esmeraldas province, Ecuador (1.18236, -78.7525; 74 m).

Paratypes: All labeled Bothriechis rahimi sp. nov. in Suppl. material 1.

Proposed standard English name.

Rahim’s Eyelash-Pitviper.

Proposed standard Spanish name.

Víbora de pestañas de Rahim.

Diagnosis.

Bothriechis rahimi sp. nov. is diagnosed based on the following combination of characters: (1) two or three raised triangular or spinelike supraciliary scales; (2) anterior dorsal head scales keeled; (3) gular scales much smaller than chinshields; (4) 8-13 interoculolabials; (5) 4-5 canthals, some raised slightly forming a ridge along the canthus; (6) loreal not in contact with preocular; (7) yellow morph present; (8) dorsal bands pink and faint; (9) opposing kidney shaped dorsal marks absent; (10) black speckles on dorsal scales absent; (11) black speckling on ventral surfaces absent; (12) ventral surfaces entirely white in some individuals; (13) iris pale straw yellow with fine black speckles; (14) 21-23 dorsal scale rows at mid-body; (15) 137-145 ventrals in males, 146-151 in females; (16) maximum total length in males 336 mm, in females 494 mm.

Comparisons.

Bothriechis rahimi sp. nov. is compared to other species of the genus previously subsumed under B. schlegelii sensu lato (differences summarized in Table 2 ). It differs from all of them by having supraciliaries raised, anterior dorsal head scales keeled, 8-13 interoculolabials, faint pink dorsal bands, and low number of ventrals in both males and females. It is one of the two members of the SA Bothriechis group where the golden morph has been recorded (Fig. 26c ), albeit it is not identical to the B. nigroadspersus golden morph (Fig. 5a-c ), as it has faint pink bands. Bothriechis rahimi sp. nov. resembles B. torvus and B. nitidus . From the former, the new species differs by being smaller in body size, having less than 148 ventrals in males, supraciliaries spinelike (vs broad and triangular), and presence of yellow morph and red morph. From B. nitidus , the new species differs by being smaller in body size, having raised supraciliaries (vs low), a higher number of canthals (4-5 vs 2-3) and interoculolabials (8-13 vs 3-8), scales on the anterior dorsal surface of the head keeled (vs smooth), presence of a yellow morph, and lack of a green morph (all B. nitidus examined are green; Suppl. material 1).

Description of holotype.

An adult female, SVL 374 mm, tail length 71 mm (18.9% SVL); head length 26.8 mm (7.2% SVL) from tip of snout to angle of jaw; head width 20.5 mm (76.5% head length) taken at broadest point; rostral broader than high (3.2 × 2.5 mm); nasal divided and not fused with first supralabial; loreal about 1/5 size of pit, contacting postnasal, canthals, prelacunal, and supralacunal; prefoveals 4/2; subfoveals 1/0; postfoveals 0; prelacunal fused with second supralabial; sublacunals 2/2; supralacunal elongated and in contact with orbit; preoculars 1/1 (2/2 if supralacunal is considered a preocular); suboculars 1/1; postoculars 2/3; loreal pit large, directed anteriorly, located slightly below line drawn from center of eye to naris; supralabials 9/8 (including lacunolabial); infralabials 12/12, first pair meet posteriorly; mental broader than long (3.2 × 2.8 mm); 1 pair of chinshields; 6 pairs of gulars between chinshields and preventrals; preventrals 1; anterior internasals 3; canthals 4/5; 2/2 triangular and raised supraciliary scales; supraoculars oblong with irregular borders, 1.8 × longer than wide; intersupraoculars 6; anterior dorsal head scales keeled; posterior head scales keeled; interrictals 30; dorsal scale rows 27/23/19; ventrals 151; cloacal plate entire; 51 undivided subcaudals; tail prehensile.

Natural history.

Bothriechis rahimi sp. nov. is an arboreal snake that inhabits evergreen lowland forests usually within 25 km from the coastline. We have found vipers of this species active at night perched on stems, branches, and tangled vegetation 0.4-8 m above the ground. One individual was perched in hunting posture on a heliconia stem facing the flowers of the plant, presumably on the wait for hummingbirds. One individual was found feeding on a treefrog ( Smilisca phaeota ) and another one regurgitated an unidentified Pristimantis species, probably P. esmeraldas (field observations by Javier Aznar and JHV).

Venom.

We know of only one snakebite cause by this species in Ecuador. A photographer was bitten on the right index finger by MZUTI 3332. The victim experienced intense local pain and swelling but recovered shortly after receiving three doses of polyvalent antivenom (elaborated by Instituto Clodomiro Picado).

Distribution.

Bothriechis rahimi sp. nov. is known from at least 12 localities (listed in Suppl. material 3) along the mouths of the rivers Esmeraldas, Santiago, Cayapas, and Mira in extreme northwestern Ecuador and southwestern Colombia. The species occurs over an area of approximately 6,003 km2 of the Chocó biome and has been recorded at elevations of 11-200 m above sea level (Fig. 3 ). Approximately 7.6% of the predicted area of distribution of B. rahimi sp. nov. overlaps with that of B. nitidus , but we did not find evidence of sympatry between the two species.

Etymology.

The specific epithet rahimi is a patronym honoring Prince Rahim Aga Khan, a firm environmentalist who has inspired many with his work focused on tackling climate change, primarily in countries where the Aga Khan Development Network is active, alongside his brother Prince Hussain Aga Khan.

Conservation status.

We consider Bothriechis rahimi sp. nov. to be included in the Vulnerable category following the IUCN criteria B1a, b (i, iii, iv) ( IUCN 2012), because the species’ extent of occurrence is estimated to be much less than 20,000 km2 (Fig. 3 ) and its habitat is severely fragmented and declining in extent and quality due to deforestation. Although B. rahimi sp. nov. occurs in two protected areas (Reserva Awá and Refugio de Vida Silvestre La Chiquita), the remaining ten localities where the species has been recorded (Suppl. material 3) are in heavily human-modified areas. Based on the species distribution model presented in Fig. 3 in combination with maps of vegetation cover of Colombia ( IDEAM 2014) and Ecuador ( MAE 2012), we estimate that nearly 49% of the forest cover throughout the species’ potential distribution area has been destroyed, mostly due to the expansion of the agricultural frontier.

Figures

Figure 3. Distribution of species of Bothriechis previously subsumed under B. schlegelii sensu lato. Each colored area is a geographic representation of the suitable environmental conditions for one of the clades recovered in the phylogeny of Fig. 2. Lime green shade in southeastern Panama represents overlap between between B. nigroadspersus and B. torvus.

Figure 5. Photographs of some specimens of Bothriechis nigroadspersus in life. a. Adult female from a private collection in Costa Rica; b. MHCH 3269 adult from Guabito, Bocas del Toro province, Panama; c. Subadult from Parque Nacional Gandoca Manzanillo, Limon province, Costa Rica; d. Adult from a private collection in Costa Rica; e, f. Juveniles from Parque Nacional Gandoca Manzanillo, Limon province, Costa Rica; g. MHCH 3268 adult female from Porton, Chiriqui province, Panama; h. MHCH 3266 adult female from Chucanti Reserve, Darien province, Panama; i. Subadult from Parque Nacional Gandoca Manzanillo, Limon province, Costa Rica; j. Adult female from a private collection in Costa Rica; k. FP 001 from Cerro Gaital, Cocle province, Panama; l. MHCH 3267 juvenile male from Chucanti Reserve, Darien province, Panama. Photos by Jose Vieira.

Figure 25. Adult female holotype of Bothriechis rahimi sp. nov. ZSFQ 5055 in a. Dorsal and b. Ventral view. Photos by Alejandro Arteaga.

Figure 26. Photographs of living specimens of Bothriechis rahimi sp. nov. from Tundaloma Lodge, Esmeraldas province, Ecuador. a. Adult female; b. MZUTI 3325 adult male; and c. ZSFQ 5053 adult female. Photos by Lucas Bustamante, Alejandro Arteaga, and Frank Pichardo.