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Home , Acipenseriformes, Actinopterygii, Alligator gar, Amiiformes, Arowana, Bonefishes

Lecture 5 - Early

Three distinct classes arose from the ancestors of bony fishes

• Acanthodians

• Sarcopterygians

• Actinopterygians Lecture 5 - Early Fishes

Actinopterygii (aka ray-finned fishes)

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• • Lepisostei • Amiformes • Teleostei • • • Ostarioclupeomorpha • Lecture 5 Early Fishes

Class Subclass Subdivision

Actinopterygii Cladistia Chondrostei Neopterygii Lepisosteiformes Amiformes Teleostei Osteoglossomorpha Elopomorpha Ostarioclupeomorpha Euteleostei Actinopterygii Ray-finned fishes

• Sister of the Sarcopterygians

• First known from scales in the late (~420 mybp)

• 3 subclasses: Cladistia, Chondrostei, Neopterygii

• Previously, with Acanthodians & Sarcopterygians, formed

Teleostomi

• Teleostomi is paraphyletic…

• Relationships in the early of fishes are still unresolved

• Splits between , Osteichthyans, & Ancanthodians ~500 mybp • occurred quickly • there are many hypotheses… Actinopterygii Ray-finned fishes

• Sister taxon of the Sarcopterygians

• First known from scales in the late Silurian (~420 mybp)

• 3 subclasses: Cladistia, Chondrostei, Neopterygii

• Previously with Acanthodians & Sarcopterygians formed Teleostomi

• Scales ganoid, cycloid, or ctenoid Subclass Cladistia Polypteriformes ( & Reedfish) Subclass Cladistia Order Polypteriformes (Bichirs & Reedfish) • 11 spp. bichirs and one reedfish

• to all other Actinopterygians

• ganoid scales • enamel like ganoin on surface

• obligate air breathers Subclass Cladistia Order Polypteriformes (Bichirs & Reedfish)

Erpetoichthys calabaricus Cladistia Distribution

• limited to west and central tropical including Congo and Nile rivers

• 95 mybp

• unique pectoral fins… Subclass Chondrostei ( and paddlefishes) • taxonomic classification is very insecure

• many extinct orders • w/ derived characteristics

• only one extant order • Acipenseriformes Mostly cartilaginous

Intestine with

Fin rays more numerous than their supports

Two extant familes • Acipenseridae

• Polyodontidae Acipenseridae – (sturgeons) • restricted to northern hemisphere – 26 spp.

• mostly cartilaginous barbels protusible mouth

• extremely long lived

• in freshwater

• bony Acipenseridae – (sturgeons) huso

8.6m & 1300kg - 118 old

$5000/kg 1227 kg female had 245 kg of Polyodontidae – (paddlefish(es?)) Polyodontidae – (paddlefish)

Psephurus gladius Chinese paddlefish

…likely extinct

I hope the caviar was amazing… Subclass Neopterygii The “new fins” in town!

Fin rays equal in numbers to their supports in dorsal and anal fins

Pterygiophores Lepisosteiformes – ()

• N. & -7 spp.

• spiral valve

• air breathers

• ganoid scales Lepisosteiformes – (gars)

Alligator spatula

Up to 3m – (bowfin)

• survivor

• air breather

• males guard young

• sister to calva Amiiformes – (bowfin) • “cycloid” • no layer, just particles • analogous to teleost

• spiral valve Division Teleostei – “perfect ” Division Teleostei 96% of all extant fishes

27 anatomical synapomorphies, no molecular ones - stiffen tail • Most important are modifications to the & caudal skeleton

Four major radiations Division Teleostei 96% of all extant fishes

27 anatomical synapomorphies, no molecular ones

• Most important are modifications to the skull & caudal skeleton

Four major radiations • Osteoglossomorpha • Elopomorpha • • Euteleostei Subdivision Osteoglossomorpha - most primitive living teleost - well developed teeth on tongue Two orders: (, )

Osteoglossiformes

African butterflyfish

Knifefish

- most speciose in subdivision >200 spp. Mormyrid elephantfishes Pirarucu Osteoglossiformes gigas obligate air breathers Osteoglossiformes • males brood young in mouth 4-6 weeks • facultative air breathers Subdivision Elopomorpha larvae Leptocephalus larvae Development of Leptocephalus

Anguilliformes and Morays

Albuliformes bonefishes Freshwater migration (anguilllidae)

Anguilla rostrata

- catadromous Subdivision - Ostarioclupeomorpha Superorder Clupeomorpha

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Superorder

• Mostly molecular synapomorphies

• Anatomical synapomorphies involve and swimbladder Superorder Clupeomorpha

Anterior extension of the swimbladder enters the skull • can detect low frequency sounds (e.g. tail beats) • almost all are pelagic schooling fish

Superorder Ostariophysi

Represent 74% of all freshwater

Synapomorphies: Schrekstoff: fright substance hormone • given off when specialized dermal cells rupture

Schrekreaction: alarm response

It has been secondarily lost in some fishes Superorder Ostariophysi

Ostar = small , physa = a bladder

Weberian apparatus: a unique series of bones that connect the gas bladder with the inner ear Superorder Ostariophysi divided into two series: Series Anotophysi Series Otophysi

Gonorynchiformes (milkfishes) Siluriformes Superorder Ostariophysi divided into two series: Series Anotophysi Series Otophysi

Gonorynchiformes Cypriniformes (milkfishes) Characiformes Siluriformes Gymnotiformes

Lack Weberian Synapomorhpy: apparatus Weberian • more primitive apparatus taxon 10,222 spp. ~74% of freshwater fishes

Weberian apparatus

catfish Cypriniformes 4,239 spp. – 599 in last 10 yrs Characiformes 2,087 spp. – 305 in last 10 yrs Siluriformes 3,681 spp. – 615 in last 10 yrs Gymnotiformes 215 spp. – 77 in last 10 yrs

• most advanced Ostariophysans

• continuous, low electrical output • except in electrical eel