Bothriechis nitidus ( Guenther , 1859)

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 nitidus ( Guenther, 1859)

Figs 7 , 27 , 28

Lachesis nitidus Günther, 1859: 414. Holotype BMNH 1946.1.17.73 (Fig. 7 ), an adult of undetermined sex from "Western Andes of Ecuador".

Bothrops boussingaultii Jan, 1863: 127. Holotype MNHN 0.227, an adult (male?) from the trail between Latacunga and Guayaquil, Cotopaxi province, Ecuador.

Teleuraspis nitida Cope, 1871: 206.

Referred specimens.

All labeled Bothriechis nitidus in Suppl. material 1.

Proposed standard English name.

Ecuadorian Eyelash-Pitviper.

Spanish names.

Víbora de pestañas ecuatoriana, cabeza de candado, equis voladora ( Manabí), papagayo (Santo Domingo de los Tsáchilas), zampiña (cloud forest populations).

Diagnosis.

Bothriechis nitidus is diagnosed based on the following combination of characters: (1) supraciliary scales low and granular or two pointed but not raised; (2) anterior dorsal head scales smooth or barely keeled; (3) gular scales usually much smaller than chinshields or similar in size to chienshields in some cloud forest populations; (4) 3-8 interoculolabials; (5) 2-3 canthals, raised slightly and forming a ridge along the canthus; (6) loreal not in contact with preocular; (7) yellow morph absent; (8) dorsal bands dark reddish brown, red, or pink; (9) no opposing kidney shaped dorsal marks; (10) black speckles on dorsal scales usually absent, but present in some cloud forest populations; (11) black speckling on ventral surfaces usually absent, but present in some cloud forest populations; (12) ventral surfaces entirely white in some individuals; (13) iris pale golden yellow to light green with or without black speckles or spots; (14) 19-23 dorsal scale rows at mid-body; (15) 129-156 ventrals in males, 132-158 in females; (16) maximum total length in males 594 mm, in females 857 mm.

Comparisons.

Bothriechis nitidus 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 (3-8), a low number of ventral scales, and a green dorsum with dark reddish brown, red, or pink bands (Fig. 27 ). Bothriechis nitidus resembles B. hussaini sp. nov., but this other species occurs south of the known distribution of B. nitidus and is characterized by having the loreal scale in contact with the preocular (not in contact in B. nitidus ), supralabials spotted, dorsal scales densely stippled with black pigment, black-spotted ventral surfaces, and basal hooks of hemipenial body 4X (instead of 2X) the size of adjacent spines. Also, unlike B. nitidus , the golden morph is present in B. hussaini sp. nov. 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 red and pink.

Hemipenial morphology.

(n = 3; Fig. 28 ) Everted and inflated, the organ is deeply bilobed, calyculate and noncapitate; hemipenial lobes cylindrical, but tapering towards the capitulum; in sulcate and asulcate views, lobe crotch ornamented with densely packed spinules and spines that become larger 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 one third to one half of each hemipenal lobe densely ornamented with small calyces with strongly defined spinulate edges. In sulcate view, hemipenial body surface with small spinules medially, basal hooks present, and 2-3 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 half 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 5 rows of smaller spines (about 1/3 the size of the lateral basal hooks) that decrease in size towards the lobe crotch.

Natural history.

Bothriechis nitidus is an arboreal snake that inhabits evergreen lowland and montane forests, cloud forests, planted forests, plantations (cacao, coffee, and banana), and rural gardens. We have found vipers of this species at night perched on arboreal vegetation up to 10 m above the ground or, rarely, moving at ground level during the daytime. Individuals of B. nitidus are known to prey on frogs ( Craugastor longirostris , Pristimantis achatinus , P. walkeri , and Trachycephalus jordani ; Valencia et al. 2016; Meza-Ramos et al. 2019), anoles (personal observation by JV), hummingbirds, and mice ( Meza-Ramos et al. 2019). Valencia et al. (2016) reports that females of this species give birth to litters of 5-9 young. One specimen (FHGO 7795) lived for 12 years in captivity.

Venom.

In coastal Ecuador, 0.2-10.3% of snakebites are attributed to this species ( Betancourt 2012; Valencia et al. 2016). Kuch et al. (1996) found the venom of this species to be not hemorrhagic, weakly coagulant, and only moderately lethal (LD50 estimated as 6.5 mg/kg).

Distribution.

Bothriechis nitidus is endemic to Ecuador. It is known from at least 121 localities (listed in Suppl. material 3) along the Chocoan lowlands and adjacent foothills of the Andes in Ecuador. The species occurs over an area of approximately 37,400 km2 and has been recorded at elevations of 0-2,230 m above sea level (Fig. 3 ). An estimated 4.2% of the predicted area of distribution of B. nitidus overlaps with that of B. hussaini sp. nov. and we found evidence (MZUA.Re.288 and JM 75; Fig. 3 ) 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. An estimated 3.3% of the predicted area of distribution of B. nitidus overlaps with that of B. rahimi sp. nov., but we did not find evidence of sympatry between the two species.

Etymology.

The specific epithet nitidus is a Latin word meaning “shining” or “elegant.” It refers to the eye-catching dorsal pattern of the holotype, which is shared by most individuals of lowland populations of this species (Fig. 27 ).

Conservation status.

We consider Bothriechis nitidus to be included in the Near Threatened category following IUCN Red List criteria ( IUCN 2012) primarily because the species’ extent of occurrence is estimated to be larger than the 20,000 km2 needed to meet B1 criteria for the Vulnerable category. However, although the species occurs in numerous protected areas (no less than 30; see Suppl. material 3), the majority of the species’ forest habitat has been destroyed. Based on the distribution model presented in Fig. 3 in combination with maps of vegetation cover of Ecuador ( MAE 2012), we estimate that only ~32% of the species’ forest habitat is still standing.

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 7. Illustration of the holotype of Bothriechis nitidus by George Henry Ford taken from the original description (Guenther 1859) at the Biodiversity Heritage Library.

Figure 27. Photographs of living specimens of Bothriechis nitidus from Ecuador. a. AMARU SN adult female from Santa Rosa, Pichincha province; b. Adult from Reserva FCAT, Esmeraldas province; c. Juvenile from Verde Bambu, Pichincha province; d. Juvenile from Canande Biological Reserve, Esmeraldas province; e. Adult from Gualpi, Esmeraldas province; f. Adult from Bosque Protector La Perla, Esmeraldas province; g. Adult from Santa Lucia Reserve, Pichincha province; h. Adult from Reserva FCAT, Esmeraldas province; i. Juvenile from Santa Lucia Reserve, Pichincha province; j. Juvenile from Canande Biological Reserve, Esmeraldas province. Photos by Jose Vieira, Alejandro Arteaga, and Sebastian Di Domenico.

Figure 28. Hemipenial architecture of Bothriechis nitidus in sulcate, lateral, and asulcate views. a. MZUTI 3753 from Sachatamia Lodge, Pichincha province, Ecuador; b. MZUTI 3754 from Santa Rosa de Intag, Imbabura province, Ecuador; c. ZSFQ 5054 from Canande Biological Reserve, Esmeraldas province, Ecuador. Photos by Amanda Quezada.