Vertebrate zoology (02 bony fishes, student version)

24-Feb-14 Fishes Vertebrate Zoology OSTEICHTHYES – BONY FISH OSTEICHTHYES – BONY FISH Basic vertebrate (Kardong, 2009; p 82, 300) + Bony vertebrae replace the notochord + The notochord may become enclosed in the centrum, or more usually is lost 24-Feb-14 OSTEICHTHYES – BONY FISH about 97% of living fishes - Class Actinopterygii: ray-finned fishes - Class Sarcopterygii: lobe-finned fishes CLASS ACTINOPTERYGII Class Actinopterygii (ak’ti-nop-te-rij’ee-i) (Gr aktis, ray, pteryx, fin, wing): ray-finned fishes + Subclass Cladistia (clə-dis’tē-a) (Gr cladi, branch): bichirs + Subclass Chondrostei (kon-dros’tē-ī) (Gr chondros, cartilage, osteon, bone): paddlefishes, sturgeons + Subclass Neopterygii (nee’op-te-rij’ee-i) (Gr neo, new, pteryx, fin, wing): gars, bowfi n, teleosts Subclass Cladistia Primitive ray-finned fishes + Have rhombic heavy ganoid scales; lungs; spiracle present; + Dorsal fin consisting of to 18 finlets + About 16 species, freshwater Bichir, Polypterus bichir, of equatorial West Africa A nocturnal (night active) predator 24-Feb-14 Subclass Chondrostei Primitive ray-finned fishes + Skeleton primarily cartilage; caudal fin heterocercal; large scutes or tiny ganoid scales present; spiracle usually present; + More fin rays that ray supports + 29 species, freshwater and anadromous (Gr anadromos, running upward) Subclass Neopterygii + Skeleton primarily bone; caudal fin usually homocercal; scales cycloid, ctenoid, absent, or rarely, ganoid + Fin ray number equal to their supports in dorsal and anal fins + About 28,000 species Subclass Neopterygii Early neopterygians (nonteleost neopterygians): Two living genera + The bowfin, Amia (Gr tunalike fish) Live in shallow, weedy waters of the Great Lakes and Mississippi River basin 24-Feb-14 Subclass Neopterygii Early neopterygians (nonteleost neopterygians): Two living genera + Gars, Lepisosteus (Gr lepidos, scale, osteon, bone) - Live in eastern and southern North America - species are large, ambush predators with elongate bodies and jaws filled with needlelike teeth 10 Subclass Neopterygii The modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + Representing about 96% of all living fishes or about half of all vertebrates + Heavy dermal armor of primitive ray-finned fishes was replaced by light, thin, flexible cycloid and ctenoid scales (some lack scales) + Homocercal caudal fin 11 Subclass Neopterygii The modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + Teleosts range in size from mm adult minnows to 17 m oarfish and 900 kg, 4.5 m blue marlin 12 24-Feb-14 Subclass Neopterygii The modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + Occur from elevations up to 5200 m in Tibet to 8000 m below the surface of the ocean 13 Subclass Neopterygii The modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + Some species live in hot springs at 44 0C, while others live under the Antarctic ice at - 0C 14 Subclass Neopterygii The modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + may live in lakes with salt concentrations three times that of seawater, caves of total darkness, swamps devoid of oxygen, or even make extended excursions onto land (mudskippers) Almost every conceivable habitat 15 24-Feb-14 Characteristics of Class Actinopterygii Skeleton with bone of endochondral origin; caudal fin heterocercal in ancestral forms, usually homocercal in descendant forms; skin with mucous glands and embedded dermal scales; scales ganoid in ancestral forms, scales cycloid, ctenoid or absent in derived forms 16 Characteristics of Class Actinopterygii Paired and median fins present, supported by long dermal rays (lepidotrichia); muscles controlling fin movement within body 17 Characteristics of Class Actinopterygii Jaws present; teeth usually present with enamaloid covering; olfactory sacs not open into mouth; spiral valve present in ancestral forms, absent in derived forms 18 24-Feb-14 Characteristics of Class Actinopterygii Respiration primarily by gills supported by arches and covered with an operculum 19 Characteristics of Class Actinopterygii Swim bladder often present with or without a duct connecting to esophagus, usually functioning in buoyancy 20 Characteristics of Class Actinopterygii Circulation consisting of a heart with a sinus venosus, an undivided atrium, and an undivided ventricle; single circulation; typically four aortic arches; nucleated erythrocytes Atrium Ventricle 21 24-Feb-14 Characteristics of Class Actinopterygii Excretory system of paired opisthonephric kidneys; sexes usually separate; fertilization usually external; larval forms may differ greatly from adults 22 Characteristics of Class Actinopterygii Excretory system of paired opisthonephric kidneys; sexes usually separate; fertilization usually external; larval forms may differ greatly from adults Nervous system of a brain with small cerebrum, optic lobes, and cerebellum; 10 pairs of cranial nerves; three pairs of semicircular canals 23 CLASS SARCOPTERYGII Class Sarcopterygii (sar-cop-te-rij’ee-i) (Gr sarkos, flesh, pteryx, fin, wing): lobe-finned fishes + Powerful jaws; + Heavy, enameled scales with a dentinelike material called cosmine; + Strong, fleshy, paired lobed fins - used to clamber over benthic substrates filled with woody debris 24 24-Feb-14 CLASS SARCOPTERYGII Class Sarcopterygii (sar-cop-te-rij’ee-i) (Gr sarkos, flesh, pteryx, fin, wing): lobe-finned fishes + Lungfishes: species + Coelacanths: Latimeria species 25 Lungfish + Neoceratodus (Gr neos, new, keratos , horn, odes, form), the living Australian lungfish, may attain a length of 1.5 m + Lepidosiren (L lepidus, pretty, siren, mythical mermaid): South American lungfish + Protopterus (Gr prōtos, first, pteron, wing): African lungfish 26 Coelacanths The tail is diphycercal but possesses a small lobe between the upper and lower caudal lobes, producing a three-pronged structure The last coelacanths were believed to have become extinct 70 million years ago The remains of a coelacanth were found on a dredge off the coast of South Africa in 1938 The new species of coelacanth was found in Sulawesi, Indonesia, 10,000 km from the Comoros in 1998 27 24-Feb-14 Sarcopterygians: (a) Dipterus, fossil lungfish of the Devonian Note the heterocercal tail (b) Osteolepis, a rhipidistian of the Devonian that also had a heterocercal tail (c) Latimeria is a living sarcopterygian (coelacanthiformes) exhibiting a diphycercal tail (Kardong, 2009; p.101) 28 Characteristics of Class Sarcopterygii Skeleton with bone of endochondral origin; caudal fin diphycercal in living representatives, heterocercal in ancestral forms; skin with embedded dermal scales with a layer of dentinelike material, cosmine, in ancestral forms Paired and median fins present; paired fins with a single basal skeletal element and short dermal rays; muscles that move paired fins located on appendage 29 Characteristics of Class Sarcopterygii Jaws present; teeth are covered with true enamel and typically are crushing plates restricted to palate; olfactory sacs paired, may or may not open into mouth; intestine with spiral valve Gills supported by bony arches and covered with an operculum 30 10 24-Feb-14 Characteristics of Class Sarcopterygii Swim bladder vascularized and used for respiration and buoyancy (fat-filled in coelacanths) Circulation consisting of heart with a sinus venosus, two atria, a partly divided ventricle, and a conus arteriosus; double circulation with pulmonary and systemic circuits; characteristically five aortic arches 31 Characteristics of Class Sarcopterygii Nervous system with a cerebrum, a cerebellum, and optic lobes; 10 pairs of cranial nerves; three pairs of semicircular canals Sexes separate; fertilization external or internal Kardong, 2009; p 647 32 11 ... 10 Subclass Neopterygii The modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + Representing about 96% of all living fishes or about half of all vertebrates + Heavy dermal armor of... modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + Occur from elevations up to 5200 m in Tibet to 8000 m below the surface of the ocean 13 Subclass Neopterygii The modern bony fishes:... and ctenoid scales (some lack scales) + Homocercal caudal fin 11 Subclass Neopterygii The modern bony fishes: teleosts (Gr teleos, perfect, osteon, bone) + Teleosts range in size from mm adult