Ostariophysi

Euteleostei

•>20,000 described species

•All shapes and sizes!

•Oldest fossils >70 mya

•Bulk of vertebrate diversity

•Adipose fin, nuptial tubercles

Pharyngeal teeth

•Fusion of bony dermal plates on venter of pharynx

•Vertically aligned w/ pharyngeal gill arches

•Articulate

•Crush plant/algae cells, mollusks shells, arthropod exoskeletons

Ostariophysi

•Most of freshwater fishes (biomass and species)

•>6500 species

•Minnows, catfishes, tetras, knifefishes

•Extremely diverse body plans and ecologies

–Herbivores, detritivores, invertivores, piscivores

•Benthic eggs

Weberian apparatus

• Vertebral processes attached to swim bladder and inner ear

•Sound causes swim bladder walls to vibrate (amplifies sound)

•Bones of Weberian apparatus transfer amplified sound to inner ear (more amplification)

Schreckstoff

•Alarm pheromone secreted into water

–Released by skin when injured

–Others scatter or school more closely

•Most species small

•Live in freshwater (murky)

Cypriniformes

•2700 species

•N America, Eurasia, Africa

•Mostly stream fishes

•Primarily insectivores (some detritivores, herbivores, piscivores)

•Minnows, suckers, loaches

Cyprinidae

•Minnows & carps

•Shiners (~300 species NA)

–Notropis sp., Cyprinella sp., Luxilus sp., Lythrurus sp.

•Small, silvery

•Conspicuous breeding tubercles

•Chubs (Nocomis, Semotilus) – nest builders

–Protection & high O₂

•Red pigment in nest associates

–Predator dilution?

Cyprinidae as bioindicators

•Many “simple lithophils”

–Broadcast or attach eggs to rock

–Intolerant of siltation

•Insectivores

–Sensitive to disturbance in aquatic insect community

–A few omnivorous species not indicative of high water quality (Campostoma sp.)

Cyprinidae as bioindicators (cont.)

•Predictable minnow communities

–Diversity generally increases w/ stream size (except for large rivers)

–Replacement of headwater species w/ larger stream species

–Headwaters = Semotilus sp., Rhinichthys sp., Phoxinus sp., Clinostomus sp.

–Medium streams = Notropis sp., Cyprinella sp., Hybopsis sp., Lythrurus sp., Luxilus sp.

–Large rivers = Notropis sp., Cyprinella sp., Macryhybopsis sp.

–Deviation from predictable community often indicates disturbance

Imperiled Cyprinidae

•Moderate endemism

•Intolerant of degraded habitat

•Threatened almost exclusively by habitat destruction

–Dams

–Siltation from urban sprawl & logging

•53 T/E USFWS

•17 Cyprinidae monitored by GADNR

Cyprinella caerulea

•Blue Shiner

•Threatened USFWS

•Formerly in Cahaba River, AL & throughout upper Coosa R.

–Now restricted to Little R., AL & Conasauga R., GA

Catostomidae

•Suckers (~70 species)

–All but one in NA

•tetraploid

•Most of biomass in NA streams

•Cycleptus sp., Ictiobus sp., Carpiodes sp., Catostomus sp., Moxostoma sp., Hypentelium sp.

•Breeding tubercles

•Trio & multiple spawning

Catostomidae as bioindicators

•Insectivores, molluscivores, ooze-feeders

•Most intolerant of degraded habitat

•Predictable communities

•Headwaters = Hypentelium sp., Moxostoma sp., Catostomus sp.

•Medium streams = Hypentelium sp., Moxostoma sp. (usually several), Catostomus sp.

•Large rivers = Cycleptus sp., Ictiobus sp., Carpiodes sp.

•Sometimes difficult to collect

Imperiled Catostomidae

•Moderate to high endemism

•Dependent on free-flowing medium to large streams (little of this habitat left)

–Dams

–Siltation from urban sprawl & logging

•Western species threatened by reduced flow due to irrigation of crops, golf courses & lawns

•? T/E USFWS

•2 monitored by GADNR

Moxostoma robustum

•Robust Redhorse

•Not-listed!

•Found near and below fall-line of Oconee, Savannah, and Pee Dee rivers (GA & SC)

–Only sizable population in Oconee R.

•Only in big river habitat

Characiformes

•Characins (tetras, piranhas, etc.)

•~1500 species

•Africa, S & C America

•Dominate diurnal fauna of S. America

•Aquarium trade

•Diverse morphology

•Single species in TX & NM

Siluriformes

•Catfishes (~2400) species

•Most freshwater (>1500 new world)

•N & S America, Eurasia, Africa

•Scaleless or covered w/ bony plates

•Barbells

•Nocturnal

•Important food fishes

Ictaluridae

•~50 species

•North America

•Streams & lakes

•Ictalurus sp., Ameiurus sp., Pylodictis sp.

•Noturus sp.(>30 species)

–Madtoms – small, benthic, stream fishes,

–Insectivores, piscivores

–Exclusively Eastern NA, highly endemic

–Many imperiled

Imperiled Noturus

•High degree of endemism & intolerance for degraded conditions

–Noturus sp. cf munitus – Etowah & Conasauga

–Noturus crypticus – Little Chucky Cr., TN

–Noturus baileyi – Citico Cr., TN

–Noturus flavipinnis – a few upper TN R. tribs

–Noturus trautmani – extinct, known from 1 riffle in Big Darby Cr., OH