Vert Morph (ZOOL 518) - Exam 2

Comparative Morphology & Biology of Vertebrates Fall 2023 (ZOOL 518) - Exam 2 ( Agnathans, Chondrichthyes, Osteichthyes), University of New Hampshire

Agnathan

jawless fishes, including lamprey, hagfish, and ostracoderms

Cyclostomata

class of agnathans that includes hagfish and lamprey, animals with circular mouths

Ostracoderm

extinct group of armored agnathans that had cellular bone and heterocercal tails

Chondrocranium

top part of the skull

Myxiniformes

order comprised of hagfish

Gnathostome

superclass including all animals with a jaw

Petromyzontiformes

Class comprised of lamprey

Arcualia

small blocks of cartilage that are dorsal to the nerve cord; primative vertebrae

Myomere

chevron shaped masses of muscles arranged in segments along main axis of the body

Myoseptum

thin sheets of connective tissue that connect myomeres

Sinus Venosus

receives oxygen poor blood and sends it to the atrium

Atrium

receives blood from sinus venosus and pumps it into ventricle

Ventricle

receives blood from atrium and pumps it to ventral aorta

Conus Arteriosus

tube where deoxygenated blood exits the heart

Ventral Aorta

receives blood from ventricle and takes it to gills

Fish

word used when speaking about a single fish or multiple fish of the same species

Fishes

word used when speaking about multiple fish comprising of at least 2 species

Chondrichthyes

cartilaginous fishes, sharks, skates, rays, holochepali

Osteichthyes

Superclass comprised of bony fishes, highly diverse

Actinopterygii

subclass comprised of fin rayed fish, most diverse group of vertebrates

Sarcopterygii

subclass of comprising of lobe-finned fishes, have cosmoid scales, actinista, dipnoi, and rhipidistians

Chimaeriformes

order under Chondrichthyes consisting of chimeras, ratfish, rabbitfish

Holocephali

other branch of Chondrichthyes besides elasmobranchii, very different, includes chimaera and ratfish

Elasmobrancii

infraclass consisting of sharks, skates, and rays

Spiracle

modified gill slit found in Chondrichthyes, allows them to bring water to the gills without opening moutn

Mulliform teeth

teeth fuse together to form crushing plates, found in batoids

Pectoral Girdle

skeletal element that joins the forelimbs or fins to the body

Coracoid Bar

bar across pectoral girdle and attached to vertebrae that supports fused fins in elasmobranchii

Pelvic Girdle

skeletal element that joins hind limbs or fins to the body

Ischiopubic Bar

bar across pectoral girdle and attached to vertebrae to support fused fins in elasmobranchii

Anguilliform Movement

‘eel like’ movement, lots of head movement

Thunniform Movement

‘tuna like’ swimming, little head movement

Heterocercal Tail

tail where the top and bottom lobes of the caudal fin are different sizes / shapes

Homocercal Tail

tail where both lobes are the same size

Placoid Scales

small, vascularized, scales that are made out of tooth-like material

Lateral Line System

sensory organ that detects vibrations

Electroreception

ability to perceive electrical stimuli

Ampullae of Lorenzini

found around the head of Chondrichthyes (pectoral fins of batoids), electroreceptor

Basal Pterygiophores

(# differs between pectoral and pelvic girdle)

Radial Pterygiophores

bones that support the fins of a fish

Ceratotrichia

Slow-Twitch Muscle

aka red muscle, containing more myoglobin, slow and sustained movements, doesn’t fatigue as easily

Fast-Twitch Muscle

aka white muscle, fatigues quicky, rapid contractions

Placodermii

extinct class of gnathostome that had a plate like armor for skin, internal cartilage skeleton, and a heterocercal tail

Teleostomi

group of fish that encompasses the majority of living species, have homocercal tails, swim bladders, circular scales, uroneural bones, and ossified vertebrae.

Pectoral Fin / Limb

fin/limb in attached to the pectoral girdle (front)

Pelvic Fin / Limb

fin/limb attached to the pectoral girdle (back)

Tesserae

found in Chondrichthyes, prismatic calcification in cartilage not the same as bone

Splanchnocranium

derived from neural crest cells, involves pharyngeal arches ( incl. hyoid and mandibular arches)

Squalene

oil found in shark liver, they have this instead of a swim bladder

Mandibular Arch

comprised of the palatoquadrate and meckal’s cartilage, used for respiration and feeding

Hyoid Arch

anchors palatoquadrate

Palatoquadrate

dorsal part of the mandibular arch, upper jaw

Meckel’s Cartilage

ventral part of the mandibular arch, lower jaw

Hyostylic Jaw Suspension

modern type of jaw suspension, involves orbital processes

Acanthoidii

extinct class of gnathostome fish

Paleoischiformes

taxonomic group of Osteichthyes that includes paddlefins and bichir, they have ganoid scales

Neopterygii

group that includes all Teleostei and Holostei fish, have uroneural bones, ossified vertebrae, double layered scales

Teleost

large, diverse group of ray finned fish

Euteleost

actinopterygii and sarcopterygii, includes most vertebrate species

Percomorph

most diverse group of teleost fish

Actinista

taxonomic group comprised of coelcanth

Dipnoi

lungfish, paired lungs and gills

Dermatocranium

bones that overlay the chondrocranium and splanchnocranium

Lepidotrichia

elongated parts of fin rays

Swim Bladder

air/gas filled sac that allows for maintaining buoyancy

Ganoid Scales

found on species like paddlefins and bichir, they have an enamel like coating and fit together like legos

Cosmoid Scales

scales found on extinct species, likely arose from the fusing of placoid scales

Diphycercal Tail

tail that scaroptergyii have, spinal column extends to end of tail horizontally

Circular Scales

type of scale found on some bony fish, smooth and round

Uroneural Bones

modified neural arches in caudal fins, help with stiffness

Operculum

structure that covers the gill opening

Monobasic Fin

fins that lobe finned fish have

Intracranial Joint

feature of some Sarcopterygii such as coelacanth

Rostral Organ

electroreceptor organ, different from ampullae of Lorenzini, found in coelacanths

Obligate Air Breather

lepidosirenidae and proitopteridae lungfish, have to breath air to survive

Facultative Air Breather

ceratondontidae lungfish, can breath air for up to 1 day when needed

Estivation

state that lungfish can enter where the heart rate drops, metabolism slows, urea is retained, and they cocoon in mud and mucus

A-

prefix meaning without

Gnatho-

prefix meaning jaw

Cyclo-

prefix meaning circular

Stoma-

prefix referring to the mouth

Isosmotic

body fluids have the same salinity as the environment

Origin of Vertebrates

1) Prevertebrates

2) Agnathan

3) Gnathostome

Buccal Funnel

possessed by lamprey, attaches to prey and releases anticoagulant

Anadromous

Live in the ocean, but return to freshwater to spawn

Orbital Processes

attach upper jaw to skull with ligaments

Branchial Basket

cartilaginous structure that supports gills in lower vertebrates

Branchio-

prefix meaning gills

Ichthy-

prefix relating to fish

Osteo-

prefix relating to bone

Chondro-

prefix relating to cartilage

Batoidea

Superorder consisting of skates and rays

Mulliform teeth

rows of teeth that fuse together to create crushing plates

Extrinstic Ocular Group

axial muscle group involving the rotation of the eyeball

Branchiomeric Muscle Group

group of axial muscles that are found between the epibranchial & hyobranchial groups, involved in breathing and swallowing

Epibranchial muscle group

muscle group involved in elevating the cranium

Hypobranchial Muscle Group

muscle group that functions to move the lower jaw

Synapomorphies of Gnathostomes

paired fins or limbs, 3 semicircular ear canals, paired nostrils

Elasmo-

thin plate