Ichthyology Notes BIOE 127 - 01
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This 8 page Class Notes was uploaded by Brianna Samoniantz on Tuesday October 13, 2015. The Class Notes belongs to BIOE 127 - 01 at University of California - Santa Cruz taught by Bernardi,G. in Fall 2015. Since its upload, it has received 47 views.
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Date Created: 10/13/15
Lecture 4 Early Fishes 1 Chondricthyes 2Acanthodians 3Sarcopterygians 4Actinopterygians Chondricthyes Class Cartilaginous skeleton fishes calcified not ossified o holocephaliratfishchimerasubclass o gill cover over about 4 gills 0 top jaw fusedattached to cranium o elasmobranchiisharksrayssubclass 0 have 57 gills o teeth are serially replaced I palaeoselachiiCohortextinct I euselachii cohort o protoselachiisubcohortextinct o neoselachiisubcohort Have skull with no sutures undergo internal fertilization with claspers high blood concentration of urea Rough estimates from 1989 that Rays make up 55 of Chondricthyes Sharks 42 and Chimaeras around 3 More on Subclass Elasmobranchii SharksRays a few morphological differences 0 gill slits on sides of sharks vs ventrally placed gills on rays 0 there is an anterior edge of pectoral fin of sharks whereas ray dorsal fins are attached creating their flat structured body 0 small lateral spiracles on sharks are located posterior to their eyes vs large spiracles on dorsal side of rays 0 spiracles allow for passage of oxygenated water through gills teeth not fused to jaws and are replaced serially o serially replaced teeth are constantly growing teeth sharks lose teeth and replace them in a conveyer belt like fashion If one is lost in the front row the teeth in the preceding row will move fonNard to fill in the empty spaces as a group they are relatively large bodies 0 90 are greater than 30 cm long 0 50 gt 1m 0 20 gt 2m Shark Orders hexanchiformes cow and frill sharks squaliformes dogfish sharks pristiophoriformes sawsharks squatinoformes angel sharks heterodontiformes bullhead sharks orectolobiformes carpet sharks lamniformes mackerel sharks carcharhiniformes ground or requiem sharks 0 gt 50 of sharks Hexanchiformes cow and frill sharks six gill sharks Squaliformes dogfish sharks ovoviviparous type of reproduction embryos will grow inside eggs that hatch within the body before giving birth could lead to intrauterine cannibalism if one egg hatches before the others eating other embryos dwarf lantern shark is a little known species of dogfish sharks the smallest shark Pristiophoriformes sawsharks relatively small 18 m use blade rostrum and laterally slash prey have sensory barbels tastebuds only Squatinoformes angel sharks fun fact hunted and sold as scallops benthic piscivores carnivorous animals eating primarily fish in benthic areas Heterodontiformes bullhead sharks type of bullhead is a horn shark spine on each dorsal fin oviparous type of reproduction parent lays the egg and then spawn hatches o mermaid purse holds and surrounds the fertilized eggs of some sharks skates and rays Orectolobiformes carpet and nurse sharks exwhale sharks filter feeders nurse sharks can ventilate their gills allows them to lie down Lamniformes Mackerel Sharks also ovoviviparous ex Thresher sharks Goblin Sharks have protruding mouth to catch prey SO COOL Ze Megamouth mesopelagic animal For both Lamniformes and Orectolobiformes filter feeding has evolved 3x in sharks Carcharhiniformes ground sharks gt 50 of shark species oceanic whitetips scalloped hammerheads oviparous ovoviviparousand viviparous o viviparous type of reproduction development of the embryo inside the mother s body eventually leading to live birth Ray OrdersFamilies Rajiformes rays skates Pristiformes sawfish Torpediniformes Electric Rays myliobatiformes stingrays eagle rays rhinobatidaerhinidae families guitarfishes Compact group relative to sharks skates are one order of rays Rajiformes Rhinobatidae family guitarfishes bodies intermediate between sharks and skates feed mainly on invertebrates oviparous Rajiformes Rajidae family Skates fleshy tail lacks spine dorsal fin present Pristiformes sawfishstill consider rays rostrum loaded with electroreceptors can grow fairly large up to 7m teeth are discreteparallel on rostrum Torpediniformes electric rays torpedo rays generate electrical discharges same voltage as defibrillator Myliobatioformes Dasyatidae family stingrays whipike tail with stinging spine oviparous Myliobatidae family eagle and mobula rays ovoviviparous Acanthodians Class extinct oldest fossils of relatively advanced fishes most likely water column feeders synapomorphies 5 gill arches heavy armors anal pelvic intermediate pectoral and dorsal spines all lived about 440280 mya Sarcopterygians Class lobe finned vertebrates skeleton primarily of bone makes up vast majority of fish lateral line is retained humans part of this group tetrapods synapomorphies enamel on teeth the hardest tissue of any animal not a synapomorphy as of last week so this is controversial have the basic arm and leg functionmovement because their fins are characterized by a thick and bony central axis including muscles contained within the fin Two Subclasses Coelacanthimorpha Coelacanths Dipnotetrapodomorpha LungfishTetrapods Coelacanthimorpha 0 first appeared 380 mya and were thought to have been extinct for 65 my 0 Ovoviviparous o Genus Latimeria after founder Marjorie Latimer who discovered coelacanth in 1938 0 located along the coast of southsouth eastern Africa also north of austrailia highest diversity about 200230 mya have intracranial jointit is unique to coelacanths allowing the front parts of their heads to lift while feeding and increases their gape 0 only have lungs as embryos once hatched the lung has receded and shrinks more as an adult 0 they move in a similar motion to tetrapods Dipnotetrapodomorpha 0 Three types of lungfish South American 1spp African4spp and Australian1spp o fins are kind of like limbs use their pelvic fins as anchors and fulcra to raise the front part of their bodies towards the surface also while breathing in the shallow water 0 estivation in lungfish in the summer there is no water once dried up so they dig underneath and downward into the ground by consuming and then expelling mud out of their gills then they create a burrow filled with mucus and slow their breathing and heartbeat to about 1 per minute 0 Devonian Lungfish and amphibians are noted to have similarities in toothbearing circumorbital temporal and opercular bones just proportioned differently Lecture 5 Early Fishes cont Actinopterygians Class Ray finned fishes Subclasses o Cladistia o Chondrostei o Neopterygii 0 Order Acipenseri and Amiiformes Lepisostei 0 Division Teleostei I Subdivisions o Osteoglossomorpha o Elopomorpha o Ostarioclupeomorpha o Euteleostei Sister taxon of the Sarcopterygians scale types include cycloid small silvery scale classic looking fish scale ganoid rubbery and thick has ganoin which makes the scale ctenoid rough with edges that have ctenii which means comb like structures giving protection and also hydrodynamic properties to the fish also placoid scales such as denticles previously formed teleostemi with acanthodians and sarcopterygians Teleostemi includes acanthodians sarcopterygians and actinopterygians however 0 teleostemi is paraphyleticmeaning it doesn t include all of the descendants of a single common ancestor also the relationships of the early evolution of fish have not been resolved there were separations between chondricthyes osteicthyans and acanthodians about 500 mya which occurred quickly 0 there are many hypotheses about the group teleostemi Cladista subclass Order Polypteriformes Bichirs11 sppRopefish1 spp sister group to all other actinopterygians neopterygians and chondrostei contain ganoid scales w enamel like ganoin on exterior air breathers surface distribution of cladistia west and central tropical africa including congo and nile rivers appeared about 95 mya have unique feather like pectoral fins Chondrostei subclass sturgeons and paddlefish the taxonomic identification is insecure there is only one existing order 0 acipenseriformes o mostly cartilaginous o heterocercal lobe o intestine with spiral valve 0 have more fin rays than their basal supports 0 two existing families acipenseridae and polyodontidae Acipenseriformes order Acipenseridae family 0 sturgeons 26spp restricted to northern hemisphere mostly cartilaginous long lived reproduce in fresh waters physicalities bony scutes along bodyarge scales protecting them have 5 rows as the fish grow older scutes recede also barbels and protrusible mouth can extend mouth at will 0 popularly hunted for caviar esp in russia Poyodontidae family 0 paddlefish 0 use paddle like rostrum to sense plankton with its magnetic sensors helpful in their habitat of murky water since they have tiny eyes Neopterygiians subclass more new fish or most well known to us their fin rays are equal in numbers to their pterygiophores of the dorsal and anal fins pterygiophores organs that carry the fish39s fins Lepistosteiformes order gars 7spp in north and central america have spiral valve are air breathers have ganoid scales Amiiformes order bowfin only survivor air breather and has spiral valve sister to teleost have cycloid scales Division Teleostei that or makes up 96 of all extant species 27 anatomical synapomorphies no molecular ones 0 most important are the modifications to the skull and the caudal skeleton Four major subdivisions 0 osteoglossomorpha o elopomorpha o ostarioclupeomorpha o euteleostei Osteoglossomorpha most primitive teleost teeth developed on tongue synapomorphies are the bony tongue two orders Hiodontiformes mooneye goldeye Osteoglossiformes Elopomorphs leptocephalus larvae meaning small headed larvae smal head compared to the body size can be 12 m long families elopiformes tarpons albuliformes bonefishes anguilliformes eels are catadromous o catadromous live in water and spawn in the ocean Ostarioclupeomorpha Super Order clupeomorpha Super Order ostariophysi both mainly have molecular synapomorphies inner ear swimbladder anatomical synapomorphies Clupeormorpha anterior extension of the swimbladder enters the skull can detect low frequency sounds tail beats Clupeiformes order almost all are pelagic schooling fish like anchovies herrings Ostariophysi small bonebladder represent 74 of all freshwater species two series anotophysi and otophysi synapomorphies Shreckstoff fright substance a hormone is given off when dermal cells are damagedruptured for example if you were to rattle a tank that water will have the hormone released by the fish Otophysi series orders cypriniformes characiformes siluriformes gymnotiformes synapymorphy Weberian Apparatus a unique series of bones that connect the gas bladder with the inner ear of the fish anotophysi series orders gonorynchiformes ack weberian apparatus this is a more primitive taxon
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