Bothriechis

Species that belong to this genus typically reach lengths of 60–80 cm, while B. aurifer, B. bicolor and B. lateralis are known to grow to 1 m or more.[3]

General characteristics include a sharply defined canthus rostralis, an unelevated snout, a rostral scale that is not as high as it is broad, and a prehensile tail that accounts for at least 15% of the body length.[3]

The color pattern usually consists of a green ground color that may or may not include pale or dark markings. B. schlegelii is an exception to this rule.[3]

Occurs in southern Mexico (southeastern Oaxaca and the northern highlands of Chiapas), through Central America to northern South America (Colombia, western Venezuela, Ecuador and northern Peru).[1]

As a general rule, species found above 1,500 meters altitude tend to be diurnal, while those found below 1,000 meters tend to be active at night. Those found between 1,000 and 1,500 meters may be active at any time of the day.[3]

Bothriechis venom is primarily a haemotoxin which causes severe pain, swelling, bleb formation, bruising, and quite often necrosis. If untreated it can lead to loss of a limb, or even death. Each year several farmers and plantation workers are bitten by eyelash vipers, sometimes resulting in fatalities. Wyeth in the United States and Instituto Clodomiro Picado in Costa Rica both manufacture different polyvalent antivenins which can be used to treat eyelash viper envenomations.

There are 11 recognized species.[7]

Image	Species[5]	Taxon author[5]	Common name[3]	Geographic range[1]
	B. aurifer	(Salvin, 1860)	Yellow-blotched palm-pitviper	Mexico, in the mountains of eastern Chiapas, in northern Guatemala. Occurs in cloud forest at 1200–2300 m altitude.
	B. bicolor	(Boucourt, 1868)	Guatemalan palm-pitviper	The Pacific slope of southeastern Chiapas in Mexico, eastward to south-central Guatemala. Also known from several locations in Honduras, including the southern part of the Sierra del Merendón and Cerro Santa Bárbara. Occurs in cloud forests at 500–2000 m altitude.
	B. guifarroi	Townsend, Medina-Flores, Wilson, Jadin & Austin, 2013[8]	Guifarro's palm-pitviper	Honduras at 1015–1450 m altitude. "Found in the western portion of Cordillera Nombre de Dios, Department of Atlantida, Honduras."[6]
	B. lateralis	W. Peters, 1862	Side-striped palm-pitviper	The mountains of Costa Rica and western Panama, including the Cordillera de Tilarán, the Cordillera Central and the Cordillera de Talamanca to the provinces of Chiriquí Province and Veraguas. Occurs at 850–980 m altitude.
	B. marchi	(Barbour & Loveridge, 1929)	Honduran palm-pitviper	The Atlantic versant of northwestern Honduras and eastern Guatemala. Occurs in mesic forest at elevations of 500–1500 m altitude.
	B. nigroviridisT	W. Peters, 1859	Black-speckled palm-pitviper	The mountains of Costa Rica and Panama. Also found in the cloud forests of the Cordillera Central and the Cordillera de Talamanca at 1150–2400 m altitude.
	B. nubestris	Doan, Mason, Castoe, Sasa, & Parkinson, 2016	Talamancan palm-pitviper	Costa Rica. San Isidro de El General, Province of San José at approximately 3000 m altitude.
	B. rowleyi	(Bogert, 1968)	Mexican palm-pitviper	Mexico in southeastern Oaxaca and northern Chiapas. Occurs in cloud forests at 1500–1830 m altitude.
	B. schlegelii	(Berthold, 1846)	Eyelash palm-pitviper	From southern Mexico (northern Chiapas), southeastward on the Atlantic slope and lowlands through Central America to northern South America in Colombia and Venezuela. Also found on the Pacific versant and lowlands in parts of Costa Rica, Panama, Colombia, Ecuador and Peru. Occurs in mesic forest at elevations almost from sea level to 2640 m altitude.
	B. supraciliaris	(Taylor, 1954)	Blotched palm-pitviper	Only found in a mountainous area in southwestern Costa Rica. Occurs in lower montane wet forest and cloud forest at elevations from 800 m to 1,700 m.[9]
	B. thalassinus	Campbell & E.N. Smith, 2000	Merendon palm-pitviper	Guatemala, Honduras at 1370–1750 m altitude.

^T type species[1]

A new species from Guatemala and Honduras, B. thalassinus, was described by Campbell & E.N. Smith (2000). Campbell & Lamar (2004) recognize this species, as well as a ninth addition to the genus: B. supraciliaris, which was first described by Taylor (1954) as a subspecies of B. schlegelii, and is found in southwestern Costa Rica.[3]

B. guifarroi was discovered in 2010 and described by Townsend et al. in 2013, in a study that included the following suggested phylogenetic tree of the genus:[6]