BIOL 404 Ichthyology the study of fishes Fishes
BIOL 404 Ichthyology - the study of fishes
Fishes w Most numerous and diverse of the major vertebrate groups w More classes of fishes than all other vertebrates combined
Status of Fish “Humans are not the pinnacle of evolutionary progress but only an aberrant side branch of fish evolution. ” - P. B. Moyle & J. J. Cech, Jr. , 2004
Bony Fishes
Founders of Ichthyology
Aristotle w First known ichthyologist - 348 -322 BC w Recognized 117 species of fish, distinguished fish from whales
Peter Artedi w “Father of Ichthyology” - 1705 -1734 w Classification system of fishes w Standardized measurements and counts that remain basis of fish taxonomy today
Peter Artedi w Friend of Carolus Linneaus, who published his works after Artedi died by drowning in a canal in Amsterdam after a night of drinking
Carolus Linneaus w 1707 -1778 - adapted Artedi’s system to use in his Systema Naturae - basis for all future classification systems w Extremely arrogant - some believe he may have been connected to Artedi’s death (competition between them)
Georges Cuvier w 1769 -1832 - classified all known species of fishes w Conducted detailed studies of fish anatomy w Compiled early history of ichthyology
Constantine Rafinesque w 1783 -1840 - produced the most detailed early account of fish in North America Ichthyologia Ohiensis - 1820 w Natural history of fishes of the Ohio River and its tributaries
Louis Agassiz w 1807 -1873 - important volumes on classification based on fossil fishes w Strong non-believer of evolution, but work laid foundation for evolution studies of fish w Popularizer of science to American public
Johannes Muller w 1801 -1858 - in Germany - revised Agassiz’s classification system to include most major groups still used today
Albert Gunther w 1830 -1914 - British Museum - last person to attempt to describe all species of fishes in the world
David Starr Jordan w 1851 -1931 - two major texts, plus president of Stanford w Fishes of North and Middle America w Guide to the Study of Fishes (ichthyology text)
Carl L. Hubbs w 1894 -1979 - two important texts w Classification of Fishes (standard reference) w Fishes of the Great Lakes Region
Ichthyology Jobs w Applied research - state, federal agencies - fisheries management w University teaching/research w Museum research/curatorship w Collection management w Public aquaria & aquarium hobby w Conservation agencies (protection)
Position within Animal Kingdom w Phylum Chordata w Deuterostome branch along with echinoderms & hemichordates
Within Phylum Chordata w Notochord w Dorsal, hollow nerve cord w Pharyngeal gill slits w Postanal tail
Phylum Chordata w 3 subphyla w Urochordata w Cephalochordata w Vertebrata
Subphylum Urochordata w Tunicates or sea squirts
Subphylum Cephalochordata w Lancelets
Subphylum Vertebrata w Vertebrates
Evolution & Major Groups: A Quick Overview
The First Fish w Ostracoderms appear in Cambrian fossils w Class Agnatha or Ostracodermi w Jawless, bony armor, many with bony endoskeleton w Most inhabited freshwater
The Next Fish w Ostracoderms disappear and placoderms appear in Devonian fossils w Class Placodermi w Jaws, paired fins, bony armor and endoskeleton w Not directly ancestral to higher fishes w May have given rise to cartilaginous fishes
First Chondrichthyes w Appeared in late Devonian w Differed from modern sharks w Terminal mouth w Pectoral fins broadly joined to body w No pelvic claspers
Skates & Rays w Subclass Elasmobranchii (same as sharks) w Appeared in Mesozoic w Descended from primitive sharks
Chimaeras w Subclass Holocephali w Appeared shortly after primitive sharks, did not arise from them w Arose independently from placoderms?
Osteichthyes - bony fishes w Arose in late Silurian w Probably from freshwater w Followed two lines of development: w Sarcopterygii - fleshy-finned w Actinopterygii - ray-finned
Bony Fishes
Sarcopterygii: Crossopterygii w w Lobe-finned fishes Ancestral to first amphibians Tetrapod-like bones in lobe fins Thought extinct until 1939 - coelocanth in Indian Ocean
Sarcopterygii: Crossopterygii
Sarcopterygii: Dipnoi w Lungfishes - air bladder modified into “lung” w Peaked in Paleozoic, then declined w 3 living genera: Australia, Africa, South America
Bony Fishes
Actinopterygii: Chondrostei w Cartilaginous ganoids w Paddlefish and sturgeons w Became dominant during Paleozoic, then declined
Actinopterygii: Holostei w Bony ganoids w Gars and bowfin w Became dominant during Mesozoic, then declined
Actinopterygii: Teleostei w Higher bony fishes w Common modern fishes w Became dominant during Cenozoic, still dominant
Bony Fishes
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