WFC120 midterm 1

What are the superclasses?

Agnatha - jawless fish

Gnathastomata - jawed fishes

What taxnomic levels are we focused on in this course?

superclass, class, subclass, superorder

What classes are we looking at in this course?

Mixini

Petromyzontida

Chondrichthyes 

Sarcopterygii 

Actinopterygii 

Subclasses? 

Holocephali 

Elasmobranchii

Coelacanthimorpha 

Dipnotetrapodmorpha

Tetrapodamorpha? 

Cladistia

Chondrostei

Neopterygii

Teleostei

Mixini

Class
Hagfishes

• has skull

• lack jaws

• lack true vert.

Petromyzontida

Class

Lamprey

• Has skull

• Lack jaw

• has a true vert.

Chondrichthyes

Cartilaginous fishes

• Jawed (gnathostomata)

• Cartilaginous fishes that lack swim bladders

encompasses subclass

• Holocephali

• Elasmobranchii

Osteichthyes

Loose term used for these two classes of jawed fish:

• sarcopterygii

  • lobe finned

• actinopterygii

  • ray finned

Sarcopterygii

CLASS

• lobe-finned fish with flexible joints

• 3 subclasses:

  • Coelacanthimorpha

  • Dipnotetrapodomorpha '

  • tetrapodamorpha

Actinopterygii

Class

Ray-finned fishes

• 4 subclasses

  • Cladistia

  • Chondrostei

  • Neopterygii

  • Teleostei

Holocephali

Subclass of fishes under Chondrichthyes

includes the chimaeras

• bottom dwelling

• feeding on benthic inverts

• swimming with pectoral fins

• split from sharks 421 MYA

Elasmobranchii

subclass of chondrichthyes

• most diverse of chondrichthyes

  • separate gill slits, lacking swim bladders

  • includes superorder galea and squalea

Galea

SUPERORDER
Have stuff fins and swim with caudal fin

Squalea

SUPERORDER

Have flexible pectoral fins attach to head

lacking a nictitating membrane that other elasmobranch have to protect eyes

Sarcopterygii

Class
Lobed fined fish

• includes the subclasses

  • coelacanthimorpha

  • dipnotetrapodamorpha

Actinopterygii

Class of ray finned fishes

• characterized by bony structures (rays) in fins that are separated by thin skin

• high degree of control over movement

  • allowed diversity in following subclasses

    • Cladistia (bichirs)

    • Chondrostei (sturgeons and paddlefish)

    • Neopterygii (Bowfins)

    • Teleostei (modern fishes)

Cladistia — example of order, etc.

Subclass that

includes the order Polypteriformes (Bichirs)

• Anguilliform fishes 

• heterocercal tails

• heavily armored bodies

• mouth similar to tetrapods

• dorsal finlets

• spiracles for breathing

Chondrostei

subclass

encompasses 

Order Asipensiformes

Ascipensiformes

O. Ascipensiformes (Sturgeons)

from the subclass Chondrostei

• Re-evolved a cartilagenous skeleton from ossified, bony ancestors

• lack scales, have scutes instead

Neopterygii

Subclass
Encompasses Orders Lepisteioformes (Gars) and our Amiiformes (Bowfins)

• heavily armored fish with heavy scales and plates

• retainment of bony skeleton

  • symmetrical caudal fin

• large, slow-moving — strong ambush predation

• bowfins used to be diverse, but now only has one extant species

Teleostei

Subclass

• evolution of light bony scales 

  • completely symmetrical caudal fin

Osteoglossomorpha

Superorder

Includes order Osteoglossiformes

• bony tongues

  • arawana

  • elephant fishes

Elopomorpha

Superorder

Includes orders

Anguilloformes - eels

F. Megalopidae — tarpons 

Ostariophysi

Superorder

includes

• order Cypriniformes (minnows)

• order Characiformes (tetras)

• order Siluiformes (catfishes)

• order Gymnotiformes (electric eels)

• order Gonorynchiformes (milkfish)

  • skull connection from skull to swim bladder (Weberian apparatus

  • swim bladder helps w buoyancy, no spines or protective, this can help to sense when predators are around

  • Schreckstoff fear pheromone

Clupemorpha

Superorder 

includes order Clupeiformes 

• herring, shad, and sardines 

Protacanthopterygii

Superorder

Includes

• Order esociformes - Pike

• Order salmoniformes - salmon and trout

• Order Osmeriformes - smelts

Stenopterygii

Superorder

includes order stomiiformes

• deep sea fishes

  • hatchetfishes

Cyclosquamata

Superorder

includes

• Order Aulopiformes

  • Tripod spiderfish

  • Atlantic Lizardfish

Scopelomorpha

Superorder

• Order Myctophiformes 

  • lanternfish

Lampriomorpha

Superorder 

• Order lampriformes 

  • Opahs and Oarfish

Paracanthopterygii

Superorder

• Order Gadiformes - Cods

• Order Batrachoidformes - Toadfish

Acanthopterygii

Superorder

including our spiny-rayed fishes

• grouped loosely into:

  • Atherinomorphs and Percomorphs

Atherinomorphs

adapted for life at the surface

• flying fish

• live bearing mosquitofish

• Silversides

Atheriniformes

• order including surface swelling silversides and rainbow fish

Beloniformes

order within Acanthopterygii

• includes flying fish

Cypinodontiformes 

order within Acanthopterygii

• adapted for variable conditions 

  • live bearers

    • examples: mosquitofish, guppies, and killifish

Percomorphs

order within Acanthopterygii

• includes fishes adapted for diverse environments

• Deep bodied fishes

  • examples: butterfly fish and surgeonfish

Perciformes

order within Acanthopterygii

• Garbage can taxon

  • includes groupers, Notothenionoids, greenlings, snailfishes

Labriformes 

order within Acanthopterygii

• Wrasses, parrotfish, damselfish

Gobiiformes

order within Acanthopterygii

• examples include gobies, mudskippers, cardinalfishes

Cichliformes

order within Acanthopterygii

• includes cichlids, angelfish

Blenniformes

order within Acanthopterygii

• example includes blennies

Plueronectiformes

order within Acanthopterygii

• includes flatfish and halitbuts

  • migrating eyes and bottomdwellers

Syngnathiformes

order within Acanthopterygii

• includes seahorses, seadragons, and pipefish

Scombriformes

order within Acanthopterygii

• includes mahi-mahi, tuna, mackerels

Scorpaeniformes

order within Acanthopterygii

• examples are rockfish and lionfish

  • benthic foragers, venomous spines

Tetraodontiformes

order within Acanthopterygii

• porcupinefish, Mola-mola, triggerfish

Gasterosteiformes

order within Acanthopterygii

• examples include sticklebacks

Compressed

Laterally compressed body plan

ex. mola mola 

Globiform

round, spherical body plan in fish

ex. pufferfish

Anguilloform

Eel like shape in fish

ex. Moray Eel

Depressed

flattened up and down in fish

ex. halibut

fusiform

Elongated, bow/spear shaped fish

designed for holding in the water and for burst speeds

ex. northern pike

thunniform

bullet shaped fish,

ex. sharks and tuna

Elongate or shorter body plan for long distance travelling fish?

Elongate.
With an elongate plan, this allows the fish to be able to disperse energy along the body of the fish.
Being able to create eddies of turbulence and being able to dispel this energy makes travel quicker and makes fish more energy efficient.

Thunniform movement

use of mostly caudal fin for propulsion

rest of body is rigid

streamlined or lunate tail typically

Anguilliform movement

Eel-like,

Whole body is moving to disperse energy, slithering movement. Creation of S shape waves and using resistance to pull forward.

carangiform movement

Fish is using last third of body for movement 

designed for navigating less complex habitat and for burst movements instead

example — gar and barracuda

subcarangiform movement

not built for speed, more for moving through complex structures in environment

can move quickly and navigate directions in water

using whole body 

Inferior mouth

for eating benthic organisms, tend to be bottom dwellers 

ex. sturgeon

superior

mouths pointing upward

for eating things like surface insects

terminal mouths

typically for picking things on seagrasses or other structures

maybe even piscivorous

Spines versus Rays

Spines are bony, stuff and sharp and unsegmented (round)

Rays are soft, flexible, segmented and can be branched —> these are used for undulation in fish

What fish only have rays

Teleosts (subclass, largest group of ray finned fishes)

What fish have true spines in addition to rays

fish in the superorder acanthopterygian
(derived)

What are the five kinds of fins in fish?

• pectoral (P)

• pelvic (P)

• dorsal and anal

• caudal

• adipose

Where can soft rays be found on a fish?

all fins with the exception of adipose

Where can spines be found on a fish?

dorsal, anal, and pelvic

Operculum

Gill covering of a fish, bony plates that cover and protect gills inside too

Also a series of branchiostegal rays that protect gills

Nares and eyes

Smelling organs and vision

maxillary

upper jaw of fish

mandible

fish lower jaw

Ostariophysi

have hardened rays that hurt like spines 
like siluriformes or cypriniformes  (catfish or minnows)

Branchiostegal rays

found on the opTherculum of the fish, used to protect the gills

Which fins are attached to the skull of the fish?

The pectoral fins and the pelvic fins

Are rays connected to the vertebral column?

no. They are connected via skeletal muscle that can control them, same with caudal fin, which is controlled by the uroneurals

Long and pointed and lateral pectoral fins 

stability and steering in large thunniform fish

Broad, pointed, lateral, and flexible

For rapid maneuvering and sculling in compressed reef fishes

Broad, round, lateral

for stability in slow moving fishes

ex. sac sucker

broad, round, and ventral

for stability in bottom dwelling fishes

Pectoral fins in sharks 

Rigid and wing like

movable but not collapsed

operate as stabilizers and as diving planes 

Pelvic fins

ventral, paired

In ancestral fishes — posterior (abdominal)

In derived anterior (thoracic or jugular)

for stability, steering, and braking

Dorsal and anal fins

STABILITY AGAINST roll and yaw in turning

• broad and angular in reef fishes

• long on fast-moving predators like tuna and mackerel — really need stability for tuns

• small finlets as dorsal can reduce drag from turbulence

• Anguilliformes have long dorsal and anal fins to minimize energy output

The caudal fin

propulsion and breaking

shapes in caudal fin

• fast, continuous swimmers — lunate

• deep bodied and globiform —> square or rounded tails

• 
  

Adipose fin

found in salmonids

• evolved independently in silurians

• sensory function?

Fish scale differences between chondrichthyes and teleosts

Teleosts have an epidermal layer over their scales but the scales penetrate through the skin for chondrichthyes

• evolved differently in both of these

Placoid scales

Found in sharks

also known as dermal denticles

hard, tooth-like structures

can add more, don’t grow in size

Ganoid

Found in lepisosteiformes, polyteriformes, and amiiformes, also apensciformes

these scales are diamond shape and connect liek puzzle peg and socket pieces

these are thick and heavy, so many of the organisms that have these are lie in wait predators or ambush predators

Cycloid

lighter scales, found in salmonid, cypriniformes, and teleosts 

lighter and grows annual rings 

Ctenoid scales

like cycloid but has spines and teeth in margins

derived, all acanthopterygians have ctenoid, some with both ctenoid and cycloid

Lateral line anatomy

opening into subdermal layer of water flow

has neuromast cells

neuromast cells consist of

cilia and cupula 

gel like membrane in cupula that is connected to hair-like cilia to send sensory input from subdermal layer of flowing water into the central nervous system to coordinate responses in fish

• detection of vibrations and water flow in fish

Electromagnetism in fish

Fish have the ability to sense weak electrical signals moving through magnetic fields

this works like an internal compass,

• salmonids, trout, sharks and rays have this

• not fully understoof

Adam Summer

Dyeing fish skeletons to highlight anatomy

bleach and dye process

Axial versus appendicular

Axial skeleton is the skull and the vertebral column of fish

Appendicular is the rest, the support for the fins including pelvic bones and pectoral arch

-fins

How is the vertebral column of the fish different posteriorly and anteriorly

Anteriorly, there are more bone structures sticking out for muscle attachment 

• intermuscular for attachment

Neural versus pleural processes

Neural allows the vertebral column to run through

Pleural allows for the main artery to run through the fish

Jaws in ancestral fish (5)

Chondrocranium

• holds upper jaw in place

Palatoquadrate

• upper jaw

Mandible

• lower jaw

Hyoid arch

• held by the hyomandibula bone

  • process holding the hyoid arch

  • becomes our middle ear bone

Hyomandibula

• holds the hyoid arch

Jaws in derived fish differences

• diminished hyoid arch

• palatoquadrate is further back, becomes the suspensorium (rigid part of skull) 

  • hinge for the milla moved all the way to the front

  • flexibility!