Class Actinopterygii, Subclass Chondrostei, Order Acipenseriformes, Sturgeon Acipenseriformes: spiracles and Paddlefish heterocercal caudal fin Cartilaginous skeleton (secondary) spiral valve • Most primitive ray-finned fishes • Largely cartilagenous skeleton • Spiral valve • Heterocercal tail • Bony scutes and plates • Snout • No branchiostegal rays • Spiracles Actinopterygii Euteleostomi • Family Acipenseridae, 4 genera, 24 species Class Actinopterygii, Subclass Chondrostei, Order Acipenseriformes, Sturgeon and Paddlefish • Diadramous, anadramous, land locked populations Spawning in Bouie River. • Long lived Summer/Fall holding area in Pascagoula • Protrusable mouth River • Asian species – 28 feet, 2800 lbs Seaward migration in late fall. • Commercial fisheries peaked ~1890 – meat, caviar, oil • Life history • Habitat requirements (large rivers) 1 Class Actinopterygii, Subclass Chondrostei, Order Acipenseriformes, Sturgeon and Paddlefish Polydontidae - paddlefish – 2 living species – No scutes, reduced scales – Upper jaw bones fused – Feeding Ecology – Egg scatterers, no parental care – Paddle – function? Psephurus gladius – Chinnese paddlefish, one specimen caught – Conservation – loss of floodplain in 2007, one in 2003. Most likely habitat, impoundments extinct. Class Actinopterygii, Infraclass Neopterygii, Order Lepisosteiformes, gar • 7 species in one living family, Actinopterygii Chondrostei – bichir and sturgeon • North and Central America Neopterygii – all others • Mostly ossified skeleton, bony Neopterygii Holostei – Bowfin and Gars plates cover cartilageouns skull Teleostei – all others • Vertebrae are opisthocoelous – • Ganoid scales • Reduced heterocercal tails • Facultative air breathers 2 Class Actinopterygii, Infraclass Neopterygii, Order Lepisosteiformes, gar • Unique larval notocord function Lepisosteus osseus; longnose gar • Toxic eggs Atractosteus tropicus; tropical gar • Conservation concern Lepisosteus oculatus; spotted gar Atractosteus spatula; alligator gar • Dearth of ecological information Lepisosteus platostomus; shortnose gar Atractosteus tristoechus; Cuban gar Lepisosteus platyrhincus; Florida gar • Atractosteus – 3 species • Lepisosteus – 4 species Class Actinopterygii, Order Amiiformes, bowfin Class Actinopterygii,Order Amiiformes, bowfin • 1 extant species • Cycloid scales • Ganoid scales • Canine like teeth, strong jaws • Reduced heterocercal tails • Single lung (2 lobes) • Undulating dorsal fin • Single gular plate • Aquatic/aerial respiration • Eastern North America – Aestivation? – • Ocellus in juveniles and reproducing males • Abundant in swampy areas and • Parental care oxbow lakes 3 Actinopterygii Chondrostei – bichir and sturgeon Neopterygii – all others Neopterygii Holostei – Bowfin and Gars Teleostei – all others Teleostei – 60 orders •Ctenoid, cycloid or ganoid scales •Lack paired gular plate & most lack any gular plate •Branchiostegal rays present •Homocercal caudal fin •Lack spiral valve in intestine Subdivision Elopomorpha • 4 orders – Elopiformes - tenpounders – Albuliformes - bonefishes – Anguiliformes - eels – Notacanthiformes – spiny eels • 24 families, 156 genera, 856 species 4 Subdivision Elopomorpha, Order Elopiformes Subdivision Elopomorpha, Order Albuliformes – Bone Fishes • Tenpounders, ladyfish and tarpons • Small group, 12 species in two • Compressed body genera. • Deeply forked caudal fin • Large gular bone • Maxilla part of gape – two upper jaw biting bones • Record fecundity – 12 million eggs • Marine, shallow tropical regions Subdivision Elopomorpha, Order Anguilliformes Subdivision Elopomorpha, Order Anguilliformes • Eels • 738 species, 141 genera, 15 families • Sackpharynx fishes, gulpers, swallowers Nemichthyidae • Arguably the most anatomically different • shallow water, except Nemichthyidae vertebrates • marine (except Anguillidae), tropical to temperate Anguilidae Congridae Muraneidae 5 Subdivision Elopomorpha, Order Anguilliformes, Anguilidae – Freshwater eels Subdivision Elopomorpha, Order Anguilliformes, Anguilidae – Freshwater eels • Pectoral fins present • American and European eels once • Mostly catadromous – thought to be same species • Population structure within species • Most benthic, adapted to getting into/out of crevices not clear – how do they “know” where to go? • Conservation – • Fishery - Eel larvae Size distribution of american ell larvae Size distribution of European ell larvae • Elvers sold to Asian markets for up to $2000 a pound • Not clear if fishery is sustainable – Catadramous and semelparous 6.