anthropogenic Caused by the agencies of man.
anticoagulant A component of snake venom that prevents coagulation (clotting) of the blood leading to prolonged bleeding. See also Procoagulant.
arboreal Being adapted to move and live in the trees.
asl Above sea level.
autotomy The voluntary shedding of the tail as a defensive strategy, with the ability to regenerate the lost tail. See also Pseudautotomy.
basal The most primitive or ancestral member of a phylogenetic tree of related organisms.
bsl Below sea level.
bufotoxins Toxins found in the parotoid glands of toxic toads.
Caatinga A form of desert vegetation comprising arid scrubland and thorn forest, found in Brazil.
canthus rostralis A distinctive ridge that runs along the side of the head from the eye to above the nostril, often seen in vipers.
carinate, bicarinate, tricarinate Keeled body scales may bear one, two, or three keels.
caudal lure/luring Some young snakes, especially pitvipers and pythons, will slowly move the contrastingly colored tail tip to tempt potential prey within strike range.
Cerrado A form of savanna comprising woodland and grassland, found in Brazil.
Chaco A dry, hot lowland habitat found in southeastern Brazil, Paraguay, and northern Argentina.
clade A group of organisms comprising all the evolutionary descendants of a common ancestor. It may not necessarily have a name.
cloaca (adj. cloacal) The common genital-excretory opening of reptiles and birds.
cloacal plate Either entire or divided, the scale covering the cloaca.
congeneric Two or more species belonging to the same genus.
conspecific Two or more individuals belonging to the same species.
convergent evolution When unrelated organisms in different geographic areas evolve to occupy the same niche, the result being that the organisms often resemble one another, a classic case being the Green Tree Python (Morelia viridis) and Emerald Treeboa (Corallus caninus). Sometimes called parallel evolution.
crepuscular Active during dusk and dawn. See also Diurnal.
cryptic species A species that is well camouflaged to blend in with its background.
cryptozoic Inhabiting secretive, hidden habitats such as leaf litter or under stones.
dentary A tooth-bearing bone of the lower jaw of reptiles.
dichromatism Males and females are different colors.
dimorphism Males and females are different shapes or possess different adornments.
dipterocarp A type of tall tree primary forest dominant in Southeast Asia.
diurnal Active during the day, opposite of nocturnal. See also Crepuscular.
dorsal (n. dorsum) Pertaining to the upper surface of the body or head (opposite of ventral, venter).
dorsolateral On the upper flanks or sides of the body.
Duvernoy’s gland The venom producing glands of a rear-fanged snake, named for the French anatomist F. M. Duvernoy.
endemic Only found in a single defined location, i.e. an island, mountain, or country.
endotherm (adj. endothermic) An animal that maintains its body temperature metabolically, i.e. a mammal or bird.
estivate Passing the dry season in a state of dormancy, the equivalent of hibernation or brumation in the cold.
extirpation Localized extinction.
fossorial Living in the soil or sand, or in the subsoil leaf litter. See also Semi-fossorial.
frontal scale A large dorsal head scale located between the eyes (see diagram).
fynbos A specific habitat comprising evergreen scrub and heathland found in the Cape of South Africa, from the Afrikaans for “fine bush.”
genus (pl. genera, adj. generic); also subgenus The taxonomic category between family and species that contains a number of similar, presumably related, species. Some large genera are split into subgenera. Written in italics with a large case initial letter.
Gondwana, Gondwanan Pertaining to the southern super-continent following the break-up of Pangaea in Mesozoic times. Comprising South America, Africa, Madagascar, the Seychelles, Arabia, India, Australia, southern New Guinea, New Zealand, and Antarctica.
hemipenes (sing. hemipenis) The paired male sex organs of snakes and lizards.
hemolytic A component of venom that damages or destroys the red blood corpuscles.
hemorrhagin A component of snake venom that causes breakdown of blood vessels resulting in leakage of blood into the tissues.
hibernaculum (pl. hibernacula) A communal winter denning retreat used by certain snakes such as the Northern Adder (Vipera berus) or Timber Rattlesnake (Crotalus horridus).
holotype The single name-bearing specimen used to describe a species, usually housed in a natural history museum. Related specimens from the same location are known as paratypes.
incertae sedis A term that means “of uncertain placement,” indicating that a species' position in a family has not been adequately determined.
internasal The scales on the dorsum of the head, between the left and right nasal scales (see diagram).
interspace The area of background color between bands or patches of patterning.
interstitial The skin between the scales on a snake or lizard.
IUCN International Union for the Conservation of Nature.
karoo A South African semi-desert habitat.
keeled scales Keeled scales are rough because they bear one or more raised ridges (opposite of smooth scales).
loreal scale The scale located between the preocular and nasal scales (see diagram).
labials, infralabials, supralabials Of the lip scales: supralabials—the upper lip scales, infralabials—the lower lip scales; many pythons and boas have heat-sensitive pits in their supralabials and infralabials (see diagram).
macrostomatan Large-mouthed. The Macrostomata is a clade of snakes capable of preying on animals wider than their own heads, i.e. above the level of the pipesnakes and shieldtails.
maxillary The tooth- or fang-bearing bone in the upper jaw of snakes.
melanistic Where all patterning is obscured by black pigment, commonly seen in female snakes living in cooler conditions because they will warm more quickly when basking.
mental groove A groove containing a fold of loose skin down the throat of most advanced snakes that enables the articulated lower jaws to be opened widely to engulf large prey.
mental scale The anteriormost scale of the lower jaw, located between and in front of the first infralabials (see diagram). See also Rostral.
mesic A habitat with a moderate supply of water. See also Xeric.
monotypic (taxonomic) A genus containing a single species or a family containing a single genus.
morph/morphotype A phase or form of patterning that differs from the normal pattern. Some species exhibit several different morphotypes in nature.
morphology The study of variation in the body shape, size, coloration, or patterning of organisms.
MYA Million years ago.
necrosis Tissue death and destruction, possibly caused by a cytotoxic venom. May lead to amputation and limb loss.
neonate A newly born offspring of a viviparous (live-bearing) species.
nominate subspecies The subspecies that bears the same name as the species, i.e. Vipera berus berus, Natrix natrix natrix.
ontogenetic change Any change in coloration, patterning, or morphology that occurs with maturity from juvenile to adult, i.e. the change from yellow or orange to green in Green Tree Pythons or Emerald Treeboas.
ophiophagous Eating snakes, i.e. the King Cobra (Ophiophagus hannah). This is not cannibalism unless the snake eats its own species.
orthopteran Grasshoppers, locusts, and katydids.
oviparous The reproduction strategy involving laying eggs (opposite of viviparous).
parietals A pair of enlarged dorsal scales on the rear of the head behind the frontal scale (see diagram).
parthenogenesis When a female gives birth or lays eggs without contact with a male. There is only one obligate parthenogenetic snake, the Brahminy Blindsnake (Indotyphlops braminus), but there have been many cases of facultative parthenogenesis when females of normally sexual species have reproduced without a mate, usually in captivity. Obligate parthenogenes are all-female species that are always parthenogenetic, facultative parthenogenes are sexual species which have occasionally reproduced parthenogenetically.
perianthropic Living alongside man.
pheromone (adj. pheromonal) A chemical substance released into the environment by an animal to attract a mate.
phylogenetic Relating to the evolutionary relationships and diversity of organisms.
piscivore/piscivorous Feeding on fish.
polymorphic Appearing in several different morphotypes or phases.
polyvalent antivenom An antivenom developed to treat the bites of a number of unrelated venomous snakes found within the same geographical area. Opposite of monovalent antivenom—antivenom produced to treat bites from one species or group of closely related species.
postocular The scale or scales directly in front of and in contact with the eye (opposite of preocular). See diagram.
prefrontals A pair of dorsal head scales behind the internasals but in front of the frontal scale (see diagram).
procoagulant A component of snake venom that causes coagulation (clotting) of the blood. Procoagulant venoms eventually cause prolonged bleeding by using up all the clotting factor. See also Anticoagulant.
psammophilous (n. psammophile) Living in sandy environments such as deserts.
pseudautotomy/caudal pseudautotomy The voluntary loss of the tail without the ability to regenerate a new tail (lizards can regenerate their tails while autotomizing but snakes do not).
reticulate (n. reticulation) Patterning that resembles a network of lines and blotches.
riparian Relating to the bank of a river, stream, lake, or wetland.
rostral The anteriormost scale on the dorsum of the head, located between and in front of the first supralabials (see diagram). See also Mental Scale.
rugose Rough, as in keeled scales.
scutes The large regular scales of the head.
semi-fossorial Living and moving through the leaf litter or under logs. See also Fossorial.
sister species, sister taxon/taxa A pair of closely related species.
species A taxonomic rank below the level of genus which is written as a binomial in italics with only the generic part of the name receiving a large case initial letter, i.e. Vipera berus.
species complex An often widely distributed species thought to contain a number of cryptic species.
species group A group of closely related species.
specific status When a subspecies is considered distinct enough to be elevated to full species.
subcaudal The scales on the underside of the tail, usually paired, occasionally single.
subspecies A taxonomic rank below the level of species that is written as a trinomial, i.e. Vipera berus berus.
supraciliary Small scales around the eye which may be elevated into small horns in some species i.e. the Eyelash Palm-pitviper (Bothriechis schlegelii).
supraocular A large scale located above the eye (see diagram).
supralabial See Labials.
sympatry (adj. sympatric) Where two species occupy the same location and habitat.
synonym/synonymy (adj. synonymized) When a species is considered no longer valid and is subsumed into another species.
taxon (pl. taxa) Any named group of organisms at any rank, a species, genus, family.
thanatosis A defensive strategy whereby an animal “plays dead” to avoid predation.
tubercle (adj. tuberculate) A soft, raised protuberance of the skin, often of sensory nature.
type genus The genus for which a family was named, i.e. Coluber for Colubridae.
type species The first described species within a particular genus.
type locality The locality where the holotype of a particular species was collected.
ventral (n. venter) Pertaining to the lower surface of the body or head (opposite of dorsum, dorsal).
versant The land sloping down from a mountain range.
vestigial A body part that is no longer used, which has become reduced in size due to evolution.
vicariant (n. vicariance) When two populations of a taxonomic group of organisms are separated by a geographical barrier such as a river, mountain range, or ocean, resulting in them evolving differently.
viviparous The reproduction strategy involving giving birth to neonates (opposite of oviparity).
xeric A dry habitat with little or no water. See also Mesic.