Fish Exam 1

Age of the fishes and how long ago

Devonian 359 mya, all classes of fishes present

When did the first fish come on the scene

520 mya

Transitional fish

Eusthenopteron, tiktaalik, acanthostega (tetrapod)

Extant

Still surviving species

difference between parasitic lamprey and non

parasitic migrates to sea or large lake (catadromous or potamodromous)

How many fish

36,000 species out of 70,000 verts

most speciose orders of fish

Perciformes (cichlids, angelfish), Cypriniformes (minnows), Siluriformes (catfish)

african lungfish characteristics

makes burrows for dry season

diadromous

move from salinity

amphidromous

migrate from fresh to salt or vice versa not for breedign

First agnathens:

518 mid cambrian

Characteristics of phylum chordata

notocord, hollow dorsal nerve cord (precursor backbone), ventral heart, grooves in pharynx, post anal tail

Transfer from echinoderms to chordata:

calciochordata (free swimming), cephalochordata (lancelets), tunicata/Vetulicolia (whack fish?)

Early chordates

pikaia (precedes fish), Metaspriggina wolcotti, Conodontiphorida (teeth guy)

fins of a fish

dorsal, adipose, caudal, pectoral, pelvic, anal

peduncle

space between anal fin and caudal tail

more derived fish fin location

pectoral fins move upward, pelvic move more anterior

cladogram

dichotomous tree based on synapomorphies

cambrian explosion environ changes

increasing temperature, dissolving minerals, O2

agnathan evolutionary traits

dermally derived bony plates on head, muscular feeding pump

agnatha level

superclass

vertebrata level

superclass

agnatha synapamorphies

semicircular canals, gills within skeleton, pores to gills, lack paired fins, notocord rudimentary vertebral elements

gill parts agnathens

pores, gills, brachial arteries and nerves, within cartilaginous skeleton and attached to neurocranium

myxini

class, 1 semicircular canal, mouth parts keratin, dorsal arcualia in larvae

lamprey “spine”

dorsal arcualia, rudementary vetebral elements, degenerated spine

what do dorsal arcualia give rise to?

vertebral arches,

lamprey class

petromyzontida

petromyzontida features

2 semicircular canals,

larval lamprey

Ammocoetes, benthic with filter feeding

Pteraspidomorphi class

extinct agnathens, 2 cemicircular canals, dermal bone in large ventral and dorsal plates

purpose of bone in pteraspidomorphi

protection, storage of minerals

Cephalaspidomorphi class

extinct agnathen, precursor paired fins, heterocercal cuadal fin, perichondral bone around eyes

perichondral bones vs endochondral vs dermal

from surface vs inside cartilage vs connective tissues in dermis

evolution jaws

anterior gill arches form into jaws

placodermi order

extinct gnathostomata, paired fins, marine and freshwater, post ranial cartilageous skeleton, paired fins, pelvic claspers

arthrodira order

extinct placodermi, diverse and successful, head plates

arthrodira feeding development

began as detritus feeders, then sharpened head plates for predation

Microbrachius dicki

early placoderm, internal fertilization

extinction event devonian

devonian-carboniferous transition, anoxic water, Chondrichthians replace placoderms

Chondrichthyes synapomorphies

cartilaginous skeleton (flexy, light), soft unsegmented fins, lack swim bladder, placoid scales, spiral valve intestine, internal fert via claspers

elasmobranchii subclass synapomorphies

teeth replaced serially, hyostylic jaw suspension

ceratotrichia

fin rays made of keratin, present in some placoderms

what helps sharks float if not a swim bladder?

cartilaginous skeleton neutrally buoyant, swimming

placoid scales functional characteristics

small, toothlike facing one way, do not grow in size as fish grows, new ones added,

placoid scales location chondrichthyes

elasmobranchii everywhere, holocephali claspers

placoid scales morphology

central pulp cavity with blood vessels, surrounded by dentine, outermost vitrodentine like enamel

skate reproduction

always eggs

ovoviviparity example:

sand tiger eating inside womb, aplacental

chimeara feeding

two bony plates seem like buck toothed

Elasmobranchii jaw

hyostylic jaw suspension, hyomandibula suspends upper and lower jaw from cranium

holocephali

subclass, oviparous, 37 spp,

elasmobranchii threat and spp #

declining popn, 470 spp shark, 500 skates/rays

basking shark story

originally liver fisheries then damaged salmon nets

skate traits

prominent back dorsal fins, ventral gill slits, oviparous

ray traits

dorsal fins reduced or absent, ventral gill, ovoviviparous, more pelagic

sawfish traits

ray type, evidence parthenogenisis

parthenogenisis

when egg develops without any male input

acanthodii

extinct class spiny shark, all 3 bone types mostly fins, skeleton cartilage, heterocercal caudal fins, 4 orders most diverse was filter feeders, ganoid scales

ganoid scales

square shape, tough, minimal overlap

subclass Coelacanthimorpha

class sarcopterygii, bone, ancestral heterocercal, SVI, swim bladder, cosmoid scales, internal fert, ovoviviparous

why were the sarcopterygii swim bladders unique?

first example but early were filled with fat/oil, paired with vestigial lung

Porolepimorpha

extinct subclass, lungfish, numerous, morpholigcally like coelocanths

dipnoi

sister subclass to porolepimorpha, bony and cartilageous,

lung development

Coelacanthimorpha one oil filled lung another vestigial, dipnoi O2 can go to blood, early Actinopterygii connected to esophagus, ray finned disconnect, true swim bladder

difference between australian and african lungfish

australian facultative, african obligate

Rhizodontimorpha

extinct Sarcopterygii subclass, cosmoid like coelocanths

Osteolepimorpha

Sarcopterygii subclass, transition to arm, includes Eusthenopteron

parts of limb coming from euthernopteron

radius, ulna, humerus, distal radius becomes fingers

Actinopterygii developments

class, flexible upper jaw, gular plates, pectoral/pelvic fin locations, Enlargement of epibranchials, change in scales

Actinopterygii primary synapomorphy

Lepidotrichia = spines

what allows for the actinopterygii jaw to become more flexible?

premaxilla becomes primary upper jaw and maxilla rotates out since no longer fused

gular plates

carryover from dermal plates, in lower jaw

what happens to gills as fish become more derived

enlargement Epibranchials = skeleton of jaw, shark have many small then become one large with only one operculum

Scale types

placoid, ganoid, cosmoid, cycloid, ctenoid

ctenoid scale traits

spiky ends cut turbulence

cycloid and ctenoid traits

flexible overlapping

cladista traits

most ancestral subclass of actinopterygii, ganoid, notochord, SVI, 2 gular, lungs

cladista species

bichir, reedfish

chondrostei

subclass of actinopterygii, remnants ganoid, heterocercal

Sturgeon protection status

most critically endangered group of species in the world, threatened by caviar harvest, habitat loss, and recreational fishing

Sturgeon scales

fused ganoid for amored scutes, smooth between

sturgeon traits

chemosensry barbels, mostly cartilage but perichondral in vertebral column, heterocercal, SVI, opportunistic, protractible mouth,

Sturgeon evolution

body shape hasnt changed but size has

Sturgeon life history

K selected, anadromous or potodromous

how to asses potential impacts of recreational fishing on sturgeon

sub-lethal impacts assesed by reflex action mortality

Neopterygii subclass synapomorphies fin

number of fin rays equal to supports, Apomorphic state, vs multiple lepidotrichia in cladista Plesiomorphic state

Neopterygii subclass synapomorphies sperm

lost acrosomes, sperm enters micropyle, single small pore

holosti

division of neopterygii with 2 orders, gar and bowfin

gar order traits

holostei ganoid scales, functional SVI

bowfin order traits

holostei, cycloid scales, vestigial SVI

division teleostei key synapomorphy

subclass Neopterygii, uroneurals = bony extension in upper lobe from vertebrae

purpose uroneurals

stiffen upper lobe allow for faster swimming

elopomorpha key synap

subdivision of teleostei, larval Leptocephali

elopomorpha orders

anguilliformes, saccophyngiformes, (deep eels) elopiformes (tarpon), and albuliformes (bonefish)

Anguilliformes traits

eels, proto-hermaphroditism, moray eels true hermaphoradism, sequential, simeultaenous or gonochoristic

american eel traits

males south, females north, hybrids go to iceland

osteoglossomorpha key synapomorphy

subdivision with bony tounge, spe

species included in osteoglossomorpha

goldeye (only in Canada), elephantfish (generate electric fields with modified muscle), arapima (obligate air breather),