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SURVEY OF MAJOR GROUPS OF FISHES IN ILLINOIS
Today's laboratory is designed to familiarize you with the great morphological diversity found in fishes and to acquaint you with most of the major families of fishes in Illinois.
Throughout the laboratory we have placed on display identified specimens representing a variety of the fishes found in the state. You should study each specimen and, and with the aid of your textbooks, develop a classification for each fish. In addition determine and write under family, the external characteristics which places this species in the designated family. Please do not look for any internal characteristic. Since many of these specimens are irreplaceable they cannot be dissected and you will just have to take on faith that the internal characters are as outlined in your textbook.
Characteristics of major groups of living fishes
I. Class Cephalaspidomorphi No jaws, no paired fins, no true teeth, single median nostril, no horizontal semicircular canal, and cartilaginous skeleton.
Order Petromyzoniformes
Order Myxiniformes
II. Class Elasmobranchii Jaws, paired fins, paired nostrils, 3 semicircular canals including one horizontal canal, cartilaginous skeleton, upper jaw is always formed from palatoquadrate cartilage with serially replaceable teeth, scales tooth-like (placoid), fin supports hair like horny rays (ceratotrichia), no swimbladder, internal fertilization and retention of urea in blood for salt balance. gill slits 5 -7, and upper jaw not fused to cranium.
III. Class Holocephali
IV. Class Osteichthyes Jaws, paired fins, paired nostrils, 3 semicircular canals including one horizontal canal, bony skeleton, upper jaw normally with tooth-bearing premaxillae or maxillae, scales not tooth-like, fin supports large jointed rays ro spines, swimbladder commonly present (occasionally lost), generally eggs fertilized externally (occasionally internal fertilization), and no retention of urea in blood.
Subclass Crossopterygii
Subclass Dipnoi Same as Crossopterygii except internal nares and cloaca present.
Subclass Actinopterygii Fin with no axial bony support
Infraclass Chondrostei Spiracle, maxilla attached to cheek, jaws elongate, and heterocercal tail.
Infraclass Holostei No spiracle, maxilla free of cheek, jaws generally not elongate, and abbreviate heterocercal tail.
Infraclass Teleostei No spiracle, maxilla free of cheek, jaws not elongate, and homocercal tail.
Division I (Elopiformes, Anguilliformes, Notacanthiformes, and Clupeiformes); Maxillary enters gape, pneumatic duct, leptocephalus larva
Division II (Osteoglossiformes and Mormyriformes); Maxillary enters gape in most genera but not all, pneumatic duct, and no le ptocephalus larva
Division III (rest of Teleosts); Premaxillary dominates gape, pneumatic duct disappears in more advanced forms, an no leptocephalus larva
Protacanthopterygii (Salmoniformes, Cetomimiformes, Ctenothrissiformes and Gonorynchiformes) Ostariophysi (Cypriniformes and Siluriformes)
Paracanthopterygii (Percopsiformes, Batrachoidiformes, Gobiesoriformes, Lophiiformes,and Gadiformes)
Atherinomorpha (Atheriniformes)
Acanthopterygii (Res of Division III)
A CLASSIFICATION OF FISHES Subphylum Vertebrata Superclass Agnatha Class Cephalaspidomorphi Order Cephalaspidiformes (Fossil) Class Pteraspidomorphi (Fossil) Superclass Gnathostomata Class Placodermi (Fossil) Class Elasmobranchii Order Bradyodontiformes (fossil) Class Holocephali Class Acanthodii (Fossil) Class Osteichthyes Subclass Crossopterygii Subclass Dipnoi Subclass Actinopterygii Infraclass Chondrostei Infraclass Holostei Infraclass Teleostei Division I Division II Division III Order Gonorynchoiformes (milkfish) Order Lophiiformes (angler fish) |