Bothriechis hussaini, 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 hussaini sp. nov.

Figs 29 , 30 , 31

Type material.

Holotype: ZSFQ 5056 (Figs 29 , 30g ), subadult male collected on June 11, 2019 at Buenaventura Biological Reserve, El Oro province, Ecuador (-3.65467, -79.76794; 524 m).

Paratypes: All labeled Bothriechis hussaini sp. nov. in Suppl. material 1 from museum collections AMNH, DHMECN, MZUA, and ZSFQ.

Proposed standard English name.

Hussain’s Eyelash-Pitviper.

Proposed standard Spanish name.

Víbora de pestañas de Hussain.

Local Spanish names.

Cabeza de candado, víbora sol (yellow morph).

Diagnosis.

Bothriechis hussaini sp. nov. is diagnosed based on the following combination of characters: (1) supraciliary scales low and granular to triangular; (2) anterior dorsal head scales smooth or barely keeled; (3) gular scales 1/2 size of chinshields; (4) 5-8 interoculolabials; (5) 2-3 canthals, which may be flat or slightly raised forming a ridge along the canthus; (6) loreal in contact with preocular; (7) yellow morph present; (8) dorsal bands black or pink or a combination of both; (9) opposing kidney shaped dorsal marks absent; (10) black speckles on dorsal scales present; (11) black speckling on ventral surfaces prominent; (12) ventral surfaces never entirely white; (13) iris green to yellow with fine black speckles, spots, or reticulations; (14) 21-23 dorsal scale rows at mid-body; (15) 140-151 ventrals in males, 147-153 in females; (16) maximum total length in males 608 mm, in females 656 mm.

Comparisons.

Bothriechis hussaini 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 not raised, a low number of canthals (2-3) and interoculolabials (5-8), a low number of ventral scales, and a green dorsum heavily speckled with black pigment (Fig. 30 ). Bothriechis hussaini sp. nov. is similar to B. nitidus , but differs from this species by having the loreal scale in contact with the preocular (not in contact in B. nitidus ), supralabials heavily marked by black speckles, dorsal and ventral scales densely stippled with black pigment, basal hooks of hemipenial body 4X (instead of 2X) the size of adjacent spines (Fig. 31 ), and by the presence of a yellow morph (= víbora sol; Fig. 30b ). Bothriechis nitidus also resembles B. rahimi sp. nov., but this other species occurs north of the known distribution of B. nitidus and is characterized by having two or three raised and spinelike supraciliary scales, keeled anterior dorsal head scales, a higher number of interoculolabials (8-13 vs 3-8), canthals (4-5 vs 2-3), and a completely different array of color morphs, including pale gray and pink (Fig. 26 ).

Hemipenial morphology.

(n=2; Fig. 31 ) Everted and inflated, the organ is deeply bilobed, calyculate and noncapitate; hemipenial lobes cylindrical to spindle-shaped; in sulcate and asulcate views, lobe crotch ornamented with scattered spinules proximally and larger spines distally; sulcus spermaticus centrolineal, bifurcate and with walls strongly defined, bifurcation occurs below bilobation point and proximal to the base of the hemipenial body; sulcus spermaticus branch runs to lobe tips; distal half of each hemipenal lobe densely ornamented with small calyces with strongly defined spinulate edges. In sulcate view, hemipenial body surface with small mesial spinules, a pair of enlarged calcified spines (basal hooks), and 3-4 rows of smaller obliquely-arranged mesial spines that become gradually smaller towards each lobe’s capitulum; each hemipenial lobe ornamented with mesial and lateral spines about 1/4 the size of the basal hooks; the spines in each lobe are replaced distally by calyces with strongly spinulate edges. In lateral view, hemipenial body and lobes with rows of spines, but otherwise non-spiculate; distal half strongly calyculate. In asulcate view, the center of hemipenial body is nude to sparsely spiculate; hemipenial lobes ornamented with 4 rows of smaller spines (about 1/4 the size of the lateral basal hooks) that decrease in size towards the lobe crotch.

Description of holotype.

An adult male, SVL 358 mm, tail length 51+ mm (14.3% SVL; tail-tip missing); head length 29.2 mm (8.2% SVL) from tip of snout to angle of jaw; head width 21.6 mm (73.9% head length) taken at broadest point; rostral broader than high (3.1 × 1.9 mm); nasal completely divided and not fused with first supralabial; loreal about 1/2 size of pit, contacting nasal, canthals, 2 prefoveals, prelacunal, supralacunal, and preocular; prefoveals 4/5; subfoveals 2/2; postfoveals 0; prelacunal not 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 1/1; loreal pit large, directed anteriorly, located slightly below line drawn from center of eye to naris; supralabials 8/9 (including lacunolabial); infralabials 11/11, first pair meet posteriorly; mental broader than long (3.2 × 2.0 mm); 1 pair of chinshields; 5 pairs of gulars between chinshields and preventrals; preventrals 0; anterior internasals 3; canthals 3/3; supraciliary scales low and granular, with one on the left side triangular; supraoculars kidney-shaped, 2.2 × longer than wide; intersupraoculars 7; anterior dorsal head scales slightly keeled; posterior head scales strongly keeled; interrictals 28; dorsal scale rows 25/23/17; ventrals 152; cloacal plate entire; 38+ undivided subcaudals (tail incomplete); tail prehensile.

Natural history.

Bothriechis hussaini sp. nov. is an arboreal snake that inhabits evergreen lowland/foothill forests and plantations (coffee and banana). We have found vipers of this species at night or during the day perched on vegetation up to 1.2-3 m above the ground. Meza-Ramos et al. (2010) found a mouse of the genus Oryzomys in the stomach of DHMECN 2580 from El Oro province, Ecuador.

Venom.

One biologist who was bitten in the shoulder by a Bothriechis hussaini sp. nov. from Azuay province reports intense localized pain, swelling, and tachycardia with two hours from the incident (personal comments to AA, 2022). The patient received antihistamines as treatment and recovered fully within 24 hours of the bite.

Distribution.

Bothriechis hussaini sp. nov. is known from at least 55 localities (listed in Suppl. material 3) along the Pacific lowlands and adjacent Andean foothills in southwestern Ecuador and extreme northwestern Peru. The species occurs over an area of approximately 13,591 km2 in the transition area between the humid Chocó rainforests and the Tumbesian dry forests and has been recorded at elevations 1-1,680 m above sea level (Fig. 3 ). Approximately 11.7% of the predicted area of distribution of B. hussaini sp. nov. overlaps with that of B. nitidus and we found evidence (MZUA.Re.288 and JM 75) of sympatry between the two species where the model predicted it. Both species co-occur along the foothills of the Andes in the sector between Naranjal, Guayas province, and Cumandá, Chimborazo province.

Etymology.

The specific epithet hussaini is a patronym honoring Prince Hussain Aga Khan, who has devoted his life, influence, and wealth to environmental conservation since he was eleven years old. In 2014, he created a Swiss-based non-profit called Focused On Nature (FON), through which he protects endangered global biodiversity through local organizations worldwide.

Conservation status.

We consider Bothriechis hussaini 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. hussaini sp. nov. occurs in four protected areas (Reserva Ecológica Manglares Churute, Reserva Biológica Buenaventura, Reserva Forestal Cerro Samama, and Reserva Nacional Tumbes), the remaining localities where the species has been recorded (Suppl. material 3) are historical and probably do not represent extant populations. Based on the species distribution model presented in Fig. 3 in combination with maps of Ecuador ( MAE 2012), we estimate that approximately 78% 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 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.

Figure 29. Adult male holotype of Bothriechis hussaini sp. nov. ZSFQ 5056 in a. Dorsal and b. Ventral view. Photos by Alejandro Arteaga.

Figure 30. Photographs of living specimens of Bothriechis hussaini sp. nov. from Ecuador. a. CZ- 003 adult female from El Colorado, El Oro province; b. CZ- 001 adult male from El Colorado, El Oro province; c. CZ- 004 adult male from San Carlos, Guayas province; d. ZSFQ 5058 juvenile female from Buenaventura Biological Reserve, El Oro province; e. AMARU SN adult female Buenaventura Biological Reserve, El Oro province; f. subadult of undetermined sex from Buenaventura Biological Reserve, El Oro province; g. ZSFQ 5056 adult male holotype from Buenaventura Biological Reserve, El Oro province. Photos by Alejandro Arteaga and Jose Vieira.

Figure 31. Hemipenial architecture of Bothriechis hussaini sp. nov. in sulcate, lateral, and asulcate views. a. MZUTI 5872 and b. ZSFQ 5056 from Reserva Biologica Buenaventura, El Oro province, Ecuador. Photos by Amanda Quezada.