Herpetology and Evolutionary Biology Vocabulary

Comprehensive vocabulary flashcards generated from the Herpetology lecture transcript covering taxonomy, anatomy, development, sensory structures, and evolutionary history.

Herpetology

Study of amphibians and reptiles

Amphibia

Vertebrate group characterized by moist permeable skin, non-amniotic eggs that are not watertight, and often an aquatic larval form and terrestrial adult form

Permeable skin

Skin that allows substances such as gases and water to pass across it

Non-amniotic egg

Non-watertight egg characteristic of amphibians

Gymnophiona

Caecilians

Caecilians

Limbless amphibians; most are annulated and fossorial

Annuli

Ring-like segments or grooves on a caecilian's body

Fossorial

Adapted for burrowing; most caecilians are fossorial

Sensory tentacles

Retractable sensory structures found in caecilians

Vestigial eyes

Reduced eyes

Direct development

Development in which the young develop directly into a form resembling the adult without a distinct larval stage

Indirect development

Development involving a distinct larval stage before the adult form

Urodela

Salamanders

Salamanders

Amphibians generally characterized by an elongate body, well-developed tail, and usually four limbs

Anura

Frogs and toads

Urostyle

Fused postsacral vertebrae of frogs and toads

Radioulna

Robust fused forelimb structure of frogs formed from the radius and ulna

Tibiofibula

Robust fused hindlimb structure of frogs formed from the tibia and fibula

Reptilia

Vertebrates characterized by watertight skin with scales and a watertight amniotic egg

Amniotic egg

Watertight egg characteristic of reptiles in these slides

Testudines

Turtles

Carapace

Upper/dorsal portion of a turtle's shell

Plastron

Lower/ventral portion of a turtle's shell

Crocodylia

Crocodiles and their relatives

Osteoderms

Bony structures underlying the scales; occur in crocodylians, turtles, and some lizards

Rhynchocephalia

Tuataras

Gastralia

Ventral skeletal elements present in tuataras

Squamata

Lizards, snakes, and amphisbaenians

Hemipenes

Paired copulatory organs of squamates

Vomeronasal organ

Sensory organ in squamates separated from the nasal cavity and connected to the oral cavity by a duct

Transverse cloacal slit

Characteristic transverse opening of the cloaca in squamates

Taxonomy

Naming and classifying organisms based on morphological similarity

Linnaean classification

Classification hierarchy: Kingdom, Phylum, Class, Order, Family, Genus, Species

Binomial nomenclature

System in which every species receives a two-part name consisting of a generic name and specific epithet

Systematics

Practice and theory of biological classification according to evolutionary relationships

Phylogenetic systematics

Groups taxa according to evolutionary history or common ancestry

Phylogenetic tree

Branching representation of evolutionary relationships

Taxon

A classified biological group

Homologous shared derived characters

Characters inherited through common ancestry and used to define taxa in phylogenetic systematics

Apomorphy

A derived character that differs from the ancestral condition

Plesiomorphy

A character inherited unchanged from an ancestor

Parsimony

Assumption that the evolutionary sequence involving the fewest changes is most likely

Monophyletic group

A group containing all descendants of a common ancestor

Paraphyletic group

A group containing only some descendants of a common ancestor

Sister group

A monophyletic lineage most closely related to the monophyletic lineage being discussed

Outgroup

A reference group less closely related to members of the ingroup than those members are to one another

Isolecithal egg

Egg containing a small amount of yolk; seen in mammals

Mesolecithal egg

Egg containing a moderate amount of yolk; seen in most amphibians

Macrolecithal egg

Egg containing a large amount of yolk; seen in reptiles

Heterochrony

Changes in the rate of growth of different structures in the developing embryo

Paedomorphosis

Retention of juvenile characteristics because a trait fails to develop to the extent observed in ancestors

Peramorphosis

Development of a trait beyond the state or condition observed in ancestors

Hatching gland

Gland in most amphibians that secretes digestive enzymes to break down the capsule surrounding the egg

Egg caruncle

Keratinized hatching structure of turtles, crocodylians, and tuatara

Egg tooth

Dentin-and-enamel hatching structure of squamates

Cutaneous respiration

Gas exchange through vascularized skin

Lateral line system

Sensory system of aquatic amphibians that detects vibrations or movement in water

Metamorphosis

Breakdown or loss of larval structures and development of adult structures

Thyroxine

Hormone regulating metamorphosis in frogs and toads

Indeterminate growth

Continued increase in body size beyond sexual maturity

Mucous glands

One of the two major types of amphibian skin glands

Granular glands

Poison glands in amphibian skin

$\beta$-keratin

Forms the outer surface of reptilian scales

$\alpha$-keratin

Occurs in spaces between reptilian scales

Ecdysis

Periodic shedding of the outer layer of the epidermis in lepidosaurs

Chromatophores

Pigment/color cells located in the dermis

Melanophores

Chromatophores producing black, brown, or red coloration

Iridophores

Chromatophores producing iridescence through stacks of granules

Xanthophores

Chromatophores producing yellow, orange, or red coloration

Zygapophyses

Structures that strengthen the vertebral column

Chondrocranium

Component of the vertebrate skull surrounding the brain and sense organs

Splanchnocranium

Visceral arch component of the skull, including the jaws

Dermocranium

Roofing elements external to the other skull components

Anapsid

Skull condition with no openings in the temporal region

Synapsid

Skull condition with one temporal opening or fenestra

Diapsid

Skull condition with two temporal openings or fenestrae

Streptostyly

Skull kinesis in which the quadrate is attached to the skull only by ligaments

Pedicellate teeth

Amphibians teeth with a bicuspid crown anchoring teeth to base

Thecodont

Tooth attachment in which the tooth sits in a socket in the jaw; found in crocodylians

Pleurodont

Tooth attachment in a groove along the jaw; found in most lepidosaurs

Acrodont

Tooth attachment directly to the bone of the jaw; found in some lizards

Neuromast

Sensory cells with cilia that bend in response to water movement in the lateral line system

Ampullary organs

Sensory organs that detect electromagnetic fields

Pit organs

Heat-receptor-containing sensory structures found in some boids, pythonids, and viperids

Tympanum-stapes pathway

Amphibian auditory pathway for airborne sounds

Forelimb-operculum pathway

Amphibian auditory pathway for seismic sounds

Amphibian heart

Three-chambered heart consisting of two atria and one ventricle

Conus arteriosus

Structure through which blood leaves the amphibian heart before giving rise to three aortic arches

Cavum arteriosum

One of the partially divided ventricular chambers in turtles and squamates; receives oxygenated blood from left atrium

Cavum venosum

One of the partially divided ventricular chambers in turtles and squamates; receives deoxygenated blood from right atrium

Cavum pulmonale

Ventricular chamber from which blood leaves through the pulmonary trunk

Faveoli

Compartments radiating from the central lung chamber in most reptiles; gas exchange occurs across their walls

Tracheal lung

Outpocketing of the trachea present in some snakes

Air sacs

Thin-walled lung outpocketings in some squamates that hold excess air but do not perform gas exchange

Cloaca

Common chamber/opening associated with digestive, urinary, and reproductive systems

Opisthonephric kidney

Kidney type found in most adult amphibians

Metanephric kidney

Kidney type found in all amniotes

Tiktaalik

tetrapodomorph fish possessing both fish-like and tetrapod-like characters

Lissamphibians

Modern amphibian groups; date to the Permian or Triassic

Pseudosuchians

Archosaur lineage that replaced synapsids as dominant terrestrial forms before dinosaurs became dominant