Added 13 March 2004.

A Herpetological

Glossary of Terms


If you read any books or literature on reptiles, amphibians or invertebrates, sooner or later you're going to come up against words that you may only have heard in biology at school, if at all. Words like rostral, mental (nothing to do with the brain or the intelligence), distal, caudal and scute abound, particularly when telling you how to identify one species from another.

This isn't some devious plan by writers or herpetologists to preserve some sort of "in-crowd" or make themselves feel above you. Rather it is a shorthand way of passing on information. Every area of human knowledge has its own special words, and herpetology is no exception. These words are actually fairly easily understood once you've picked up the meaning. Note that some of them can be used as both nouns (eg, "The Fire Salamander is a caudate") and adjectives (eg, "the caudate circulatory system").

This list is by no means complete yet, but will be updated on a regular basis. It is not intended to be exhaustive but to help the reader understand some of the terms more commonly used on these pages, particularly species guides.

General Terms

saurian lizard
chelonian an animal that is a tortoise, turtle or terrapin; adjective relating to such an animal
anuran frog or toad
caudate newt or salamander
urodele newt or salamander
ophid snake or serpent
crocodilian relating to alligator, crocodile, caiman or gharial

Words to do with WAY OF LIFE

diurnal active by day
crepuscular active by twilight
nocturnal active by night
arboreal pertaining to trees: hence an arboreal species is a tree-dwelling species
terrestrial ground-dwelling
fossorial burrowing or living below ground
riparian living by streams or rivers
saxicolous dwelling among rocks
aestivate to reduce bodily activity during period of hot and/or dry/arid weather, usually in a place offering some protection from excessive heat or dryness; similar to, but not as intense as, hibernation (noun = aestivation)
hibernate to drastically reduce bodily activity during prolonged cold weather (usually winter), usually by entering a period of dormancy in a shelter (noun = hibernation)

Words to do with POSITION

anterior frontal, at the front
posterior rear, at the rear
dorsal top, on top: in a four-legged creature such as a lizard, salamander or cat, it refers to the creature's back, as opposed to its underbelly
ventral bottom, underneath: the opposite of dorsal. Thus, a lizard's ventral surfaces are the undersides of its limbs, its throat and its belly.
caudal tail, or pertaining to the tail
cranial head, or pertaining to the head
distal the part of something furthest from its point of attachment: thus the distal part of a toe is the opposite end to where it joins the foot
gular throat, pertaining to the throat
anal relating to the anus

Words to do with the BODY

osteoderm in crocodiles and some lizards, a bony plate directly attached below the skin to a scale above - a sort of armour plating
orbital eye socket
cloaca in amphibians, reptiles and birds, the anal opening that serves for both excreting and reproduction. Beavers also have a cloaca rather than the mammalian arrangement of a separate anus and reproductive opening.
axilla armpit
collar in some lizards, for instance, lacertids, a sort of fringe of scales between the head and neck


rostral single scale on the end of the upper jaw
postnasals one scale on either side of the upper jaw behind the rostral
supralabial  scale on the upper jaw above the lip and touching it 
infralabial  scale on the lower jaw below the lip and touching it
opercular  scale over the ear 
tubercle  a sort of raised and pointed scale: in lizards, usually found only on geckos
mental 1. pertaining to thought or mind, eg mental processes: 2. pertaining to the chin, eg mental scale, mental gland (the latter in salamanders): 3. a scale on the chin (usually when related to lizards or snakes)

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