Phylum Chordata. *Notochord, pharyngeal slits, dorsal tubular nerve chord, and postanal tail are all present at some point in the organism’s life span. Notochord - Rod-like, supportive structure that runs along dorsal midline
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*Notochord, pharyngeal slits, dorsal tubular nerve chord, and postanal tail are all present at some point in the organism’s life span.
Notochord- Rod-like, supportive structure that runs along dorsal midline
Manta Ray: no spine/barb
Teleostei - final bony fishes
• Placoid – found in sharks, they are modified on the anterior to form
teeth, they are composed of a vascular inner core of pulp, a middle
layer of dentine and a hard enamel-like outer layer of vitrodentine
• Ganoid – found in gars, bichirs and reedfish, are rhomboid in shape
and have a bony basal layer of dentine and outer layer of ganoine,
they do not overlap
• Cycloid– found in bowfin, consist of a surface bony layer and a deeper fibrous layer composed mainly of collagen
• Ctenoid – found in most teleosts, are similar to cycloid scales but
they have they have a spiny posterior margin, both cycloid and
ctenoid scales grow with the fish so they lay down concentric growth
rings and can be used to determine age and growth rates of fish.
Epicercal: the upper lobe is larger, as in sturgeons and many sharks.
Hypocercal: the lower lobe is larger, as in flying fish.
A. caudal fin - B. dorsal fin - C. lateral line - D. nostril - E. barbelF. operculum - G. pectoral fin - H. pelvic fin - I. vent - J. anal fin