Fishes
Fishes Group of aquatic limbless vertebrates, breathing mainly by means of gills, with
streamlined bodies and fins and with the body covered in scales (in bony fishes), and
comprising the Chondrichthyes (cartilaginous fishes) and the Osteichthyes (bony fishes).
The Agnatha are also sometimes called fishes
Actinopterygii The ray-finned fishes, a subclass of bony fishes (Osteichthyes) which includes all extant
bony fishes except the lungfishes (Dipnoi) and the coelacanth
Agnatha Taxon of primitive jawless verte3brates, including the lampreys (Monorhina), hagfishes
(Diplorhina) and their extinct relatives
Ammocoete Larva Larva of lamprey
Anadromous Fishes which migrate from salt to fresh water annually
Dorsal aorta Major artery carrying oxygenated blood to the rest of the body in vertebrates and
cephalochordates.
Aortic arch Paired arteries in vertebrate embryos, which connect dorsal and ventral arteries,
running between gill slits on either side
Appendicular A skeleton of the appendages
skeleton
Barbel A slender, external process on the jaw or other part of the head of certain fishes
Chondrichthyes A class of fishes known from the Devonian to the present day, commonly known as the
cartilaginous fishes, having a cartilageous skeleton, spiral valve in the gut, and no lungs
or air bladder, and including the rays, skates, and sharks
Coelcanth Members of an order of fish that includes the oldest living lineage of Sarcopterygii
(lobe-finned fish + tetrapods)
Cupula Jelly-like cup over a group of hair cells (a neuromast) in acoustic-lateralis system of fish
and amphibians and vestibular system of mammals
Cranium The skull, more particularly that part enclosing the brain
Dentine Hard elastic substance, also known as ivoery, with same constituents as bone (collagen
and calcium salts), consistuting the interior hard part of vertebrate teeth and outer
layer of denticles and dermal bone
Diphycercal tail With a caudal fin in which the vertebral column runs straight to tip, dividing the fin
symmetrically
Ectodermal Plate-like ectodermal thickenings
placodes
Euryhaline Marine organisms adaptable to a wide range of salinity
Fusiform Spindle-shaped, tapering gradually at both ends (torpedo-like)
Gas Gland Glandular portion of air bladder of certain fishes which secrets gas into the bladder
Gnathostomata The jawed vertebrates, a subphylum of Chordata comprising the fishes, amphibians,
reptiles, birds, and mammals
Heterocercal tail Having vertebral column terminating in upper lobe of tail fin, which is usually larger
than lower lobe, as in dogfish and other sharks
Homocercal tail Type of tail fin in which vertebral column ends before it, and the upper and lower lobes
are more-or-less equal
Hyperosmotic Having higher salt concentration than the surroundings
Hyposmotic Having a lower salt concentration than the surroundings Isoosmotic Having the same concentration of salts as the environment
Keratin Fibrous protein rich in cysteine, chief material in horn, hair, nails, and upper flaky layer
of skin
Lingual cartilage Cartilage pertaining to tongue
Lungfish Lobe-finned bony airbreathing fish of the subclass Dipnoi
Myxini Hagfishes (also class Agnatha)
Neural Arch Arch on the dorsal surface of vertebra for passage of the spinal cord
Neural Crest Ridge of ectoderm that forms above the neural tube during early embryogenesis in
vertebrates. The cells of the neural crest migrate to form a variety of structures.
Neuromast A group of hair cells (sensory cells) comprising a sensory unit of the acoustic-lateralis
system in fishes and some amphibians
Nostril Exterior opening of the nose (also nares)
Operculum Gill cove in fishes
Ovale A part of a swim bladder which reabsorbs gas into blood
Pectoral fin The fin on the side of body of fish
Pectoral Girdle In vertebrates, a skeletal support in the shoulder region for attachment of fore-fins or
forelimbs, made up of a hoop of cartilages or bones
Pelvic fin Paired fins on underside of body of fish, representing the hindlimbs of land vertebrates
Pelvic Girdle In vertebrates, a skeletal support in the hip portion for attachment of hind-finds or
hindlimbs, made of a hoop of cartilages or bones
Physoclistous fish Having no channel connecting swim bladder and digestive tract, as in most telosts
Physostomous fish Swim bladder connected to the GI via pneumatic duct
Pneumatic duct Connects swim bladder and GI tract
Protochordates Group of animals comprising the hemichordates, urochordates, and cephalochordates,
having gill slits, a dorsal hollow central nervous system, a persistent notochord, and a
postanal tail
Rete mirabile Small dense network of mainly arterial blood vessels in various organs of some
vertebrates
Rostum Beak-like structure (snout) of sharks
Sarcopterygii A group of mostly extinct bony fishes having fleshy fins and nostrils opening into the
mouth, comprising the lungfishes and the crossopterygians
Swimbladder A gas-filled sac in body cavity of most teleost fishes, developed as an outgrowth of the
alimentary canal, and which is an aid to buoyancy
Tongue Movable and protractible organ on floor of mouth
Fishes: Notochord with muscles attached;
2+
Early Vertebrate endoskeleton, exoskeleton, mainly Ca
Introduction & **SPECIES POINT**
Early vertebrates BIGGER protochordates
Musculoskeletal modifications
o Living endoskeleton as framework for body & internal
support structure
o Segmented body muscles W-shaped vertebrate Arrows pointing @ myomeres (greater muscle contration, enabling longer
bodies)
o Increased musculature of gills pump 2 O to get gas
Physiological modifications
o Respiratory/circulatory systems mod to support large size/active lifestyle (metab. Dmd)
o Pharynx mod into a muscular pump pass water across internal gills; chambered heart
to pump blood
Sensory system modifications [5]
o Active, predatory life new sensory/motor/integrated controls to locate/capture food
[distance reception]
Sophisticated Eyes
Pressure Receptors inner ears (equil/sound)
Chemical Receptors olfactory (smell) organs
Lateral-line Receptors vibrations in water
Electrical Receptors ampullary organs
o Neural Crest (ectodermal cells lying along embryonic
neural tube Crainum & Dentine 9teeth) [vert only]
o Ectodermal Placodes plate-like ectodermal thickenings [vert only]
Subphylum Vertebrata Maxini – Hagfish poor fossil record, changed little over milofy,
3 pairs of barbels around mouth
Eyes blind, good chemreceptors; no lateral-line
system
1-14 gill openings, & pores (can breathe while
feeding, through skin)
Caudal fin [tail], but no paired/dorsal fins
Nostril (connected to pharynx) used for water
intake
Separate internal gill openings
Cranium underdeveloped; Vertebra
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