Acrodont—Having teeth attached to the edge of the jawbone without sockets.
Anterior—The front or head of an animal.
Apical—Of, relating to, or situated at an apex.
Arribada—A massive, coordinated arrival of seaturtles, and some freshwater species, at a nesting beach.
Aspect ratios—Total length divided by body width
Autotomy—Self-amputation of a body part, typically a tail; used as a defense mechanism.
Axillary—Of, relating to, or located near the axilla; the cavity beneath the junction of a forelimb and the body.
Barbels—Fleshy, tubular extension of skin, usually on the head or neck.
Basal—Arising from the base of a stem; of, or relating to the foundation, base or essence; of or relating to, or being essential for maintaining the fundamental vital activities of an organism.
Carapace—The dorsal (upper) shell of a turtle.
Caudal luring—A specific movement of the tail which is meant to attract or lure prey; an adaption that evolved to help increase the animal's chance of getting food and therefore allowing it to survive.
Ceratobranchials—Principal paired derivatives from the 3rd through 6th visceral arches found in the hyoid apparatus (the lateral and posterior paired parts of the hyoid).
Chemoreception—The sensory reception of chemical stimuli; capacity to detect and differentiate certain chemicals in the surrounding environment.
Chromosome—Thread-like structure consisting mostly of genetic material (DNA) in the nucleus of cells.
Clade—An evolutionary lineage of organisms that includes the most recent common ancestor of all those organisms and all the descendants of that common ancestor.
Cladogram—Graphic, tree-like representation that shows the evolutionary relationships of organisms.
Concertina—A mode of locomotion in snakes, characterized by sequential extension and contraction of the body from one anchored and stationary site to the next as the animal moves with accordion-like appearance in one direction.
Congeneric—Of or belonging to the same genus.
Conspecific—Of or belonging to the same species.
Cruciform—Forming or arranged in a cross.
Crypsis—Reference to camouflage or matching between the color, pattern, or shape of an animal and a random sample of the background it is viewed against, as perceived by another animal.
Diapause—A period of physiologically enforced dormancy between periods of activity.
Dimorphism—The existence of two different forms (color, size, sex) of a species in the same population.
Distal—Toward the tip of a body extremity, such as a phalange.
Diurnal—Active by day.
Dorsal—Relating to or situated near or on the back of an animal.
Dorsolaterally—Relating to, or involving both the back and the sides.
Dorsoventrally—Relating to or involving, or extending along the axis joining the dorsal and ventral sides.
Ecdysis—The act of molting or shedding an outer cuticular or epidermal layer.
Ectoderm—The outer cellular membrane of a diploblastic animal (one whose embryo has two germ layers) or the outermost of the three primary germ layers of an embryo.
Ectopterygoid bones—Dermal bone in the palate of most reptiles.
Ectotherm—An animal whose body temperature is determined principally by the environment.
Emarginated—To deprive of a margin; having a margin notched.
Endoderm—The innermost of the germ layers of an embryo that is the source of the epithelium of the digestive tract and its derivatives.
Endotherm—An animal whose body temperature is determined by internal metabolic heat production.
Extant—The state of a taxonomic group being alive in the present; not extinct.
External fertilization—The joining of sperm and eggs outside of the female's body.
Extinct—The state of a taxonomic group being lost; no longer in existence.
Femoral—Of, or relating to the femur or thigh.
Fenestra—A small anatomical opening.
Fertilization—The penetration of an egg by sperm.
Fossorial—Adapted for or used in burrowing or digging.
Fusiform—Tapering towards each end.
Gravid—Female carrying young or eggs.
Gular pouch—A pouch of bare skin between the lower mandibles (jaws).
Hatchling—A young animal that has just emerged from an egg.
Heliothermic—Basks in the heat of the sun (or other overhead bright heat source). Commonly occurs in many temperate reptiles including squamates, crocodilians, and semiaquatic turtles. Snakes use a combination of helio-thermic and thigmothermic strategies.
Hemipene—The bi-lobed male reproductive organs in most reptiles, kept inverted in the tail until needed.
Heterospecific—Members of a different species.
Hybrid—Individual resulting from mating of parents that belong to different species.
Hyoid bone—A bone or complex of bones situated at the base of the tongue and supporting the tongue and its muscles.
Inframarginal—Lamina (thin plate or scale) lying between the marginals of the carapace and the lateral margin of the normal plastral laminae.
Inguinal fat body—Body fat relating to, or situated on the groin or in either of the lowest lateral regions of the abdomen.
Internal fertilization—Penetration of eggs by sperm inside the female's body.
Intrascalar—Within or underneath the skin.
Intromission—The act of insertion.
Jacobson's organ—A convoluted blind sac opening into the roof of the mouth and lined with sensory structures that detect odorant particles brought into the mouth on the tongue. This organ is absent in adult crocodilians. Also known as vomeronasal organ.
Keeled—A scale with a raised ridge running down its mid-line.
Keratinized—Tissue that is hardened with keratin, such as human fingernails or toenails.
Lamella—A thin, flat scale, membrane, or layer.
Lateral—Related to the side of an animal.
Loreal scale—The scale between the preocular and nasal scales.
Lotic—Of, relating to, or living in actively moving water.
Marginal—A lamina in the outer series on the carapace of a turtle, visible both from above and below and characterized by a sharp angle marking the edge of the bony part of the carapace.
Maxillary—Pertaining to a maxilla, or jaw.
Monophyletic—Developed from a single common ancestral form or line.
Monophyly—A single common ancestral form or line.
Morph—A unique body form or coloration.
Morphology—The study of an animal's shape or form.
Necrosis—Localized death of living tissue.
Nocturnal—Active at night.
Ocelli—A minute simple eye or eyespot of an invertebrate; an eyelike colored spot.
Ontogeny—The development or course of development of an individual organism.
Oviparous—Producing eggs that develop and hatch outside the maternal body.
Ovoviviparous—Producing eggs that develop within the maternal body and hatch within or immediately after extrusion from the parent.
Paramo—High-altitude habitat that is cold, wet, and dominated by grasses and shrubs.
Parietal—Of or relating to the walls of a part or cavity; of, relating to, or forming the upper posterior wall of the head.
Phalange—One of the digits in the hand or foot.
Phylogenetic—Relating to the evolutionary history of an organism or group of organisms.
Pit organ—Specialized and highly sensitive infrared receptors that detect rapid changes in infrared radiation. These have evolved independently in boid and crotaline snakes and provide very precise discrimination of the direction and distance of an infrared source. They are located in upper and lower labial scales of boid snakes and occur as single structures between the eye and nostril on either side of the head of crotaline snakes.
Plastron—The ventral (underside) part of a turtle or tortoise shell.
Pleurodont—Having the teeth attached by their sides to the inner side of the jaw.
Posterior—Related to the rear or tail end of an animal.
Postocular—That part of the head behind the eye
Prefrontals—1) Either of a pair of large scales directly anterior to the frontal scales. 2) A dermal bone forming part of the roof of the orbit.
Prehensile—Adapted for seizing or grasping especially by wrapping around an item.
Preocular—The part of the head in front of or before the eye.
Pterygoid—Of, relating to, or lying in the region of the inferior part of the sphenoid bone of the vertebrate skull.
Rectilinear locomotion—A mode of locomotion used primarily by heavy-bodied snakes that move in a straight line. Alternating sections of the ventral skin are lifted clear of the substrate and are pulled forward by muscles originating on ribs and connecting to the ventral skin.
Relict—A persistent remnant of an otherwise extinct organism.
Rostrals—Situated toward the oral or nasal region.
Sexual dimorphism—Difference of physical form (shape) or coloration between the sexes; any consistent difference between males and females beyond the basic functional portions of the sex organs.
Scute—An external bony or horny plate or a large scale.
Serpentine—Of or relating to snakes; the type of limbless movements used by snakes.
Sidewinding—A mode of locomotion in which a snake raises its body in loops and rests its weight on two or three points that are the only places where the body contacts the ground. The loops are swung forward through the air while the points of contact are moved smoothly along the body length. This locomotion is characteristic of snakes that live in deserts where sandy substrates have particles that slip and induce sliding during serpentine locomotion.
Speciose—A taxonomic group with many species.
Subcaudals—Scales on the ventral side of the tail of reptiles, commonly arranged in either a single series or two series in snakes.
Supralabials—Enlarged scales on the edge of the lip of the upper jaw.
Supramarginal—Any one of the plates situated between the mid-lateral and marginal plates of the carapace in some species of turtles.
Supraocular—Either of a pair of shields that lie dorsal to the eyes of snakes.
Suprapygals—Any of the bones (usually two) that lie across the midline of the turtle carapace, just anterior to the hindmost plate of the shell
Supranasals—Any scale located directly above the nasal scale of squamate reptiles.
SVL—Abbreviation for snout-vent length. Measures from the tip of the animal's snout to the end of its vent.
Synapomorphy—An apomorphy (derived or specialised character) shared by two or more groups which originated in their last common ancestor
Tail autotomy—A defense mechanism whereby an organism can drop its tail if it feels threatened or is grabbed by the tail. Tails have also been dropped as a result of stress.
Thigmothermic—Absorbs heat by contact with warm surfaces, for example, by lying on a warm rock. Snakes use this strategy.
Tubercles—A small projection or nodule that grows on a plant or animal.
Tuberculate—A plant or animal that has nodules or tubercles growing on them.
Tympanic membrane—Thin membrane that closes externally the cavity of the middle ear and functions in the mechanical reception of sound waves and in their transmission to the site of sensory reception.
Undulatory—A type of limbless movement in which the body moves through a series of curves while at least three points on the body slide past irregular points of contact where reaction forces are generated to move the body in the forward direction.
Ventral—Of or relating to the belly or abdomen of an animal.
Viviparous—Giving birth to live young rather than eggs.
Warts—Any hard or cornified prominence on the skin, sometimes glandular in substructure.
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