biology of fishes env 422/nre 422/eeb440 · construct a cladogram that includes the following...

Craniate Relationships Biology of Fishes

9.13.2012

Review

Morphology

Classification

Phylogenetics Assignment

Craniate Relationships

Overview

Basic Fish Morphology

Classification

Rank-based system (Linnaean)

Evolutionary history-based system (Phylogenetics)

Phylogenetics

Apomorphies, synapomorphies, plesiomorphies

Monophyly, paraphyly, polyphyly

Review

Basic Fish Morphology

Rank-based (Linnaean system, traditional)

Kingdom - Animalia

Phylum - Chordata

Class - Actinopterygii

Order - Perciformes

Family - Percidae

Genus - Perca

Species - flavescens

Classification

Yellow Perch

Construct a cladogram that includes the following groups:

Holostei (Gars & Bowfins)

Chondrostei (Sturgeons & Paddlefishes)

Dipnoi (Lungfishes, tetrapods)

Teleosts (“modern” bony fishes)

Cladistia (Bichirs)

Actinistia (Coelacanths)


A B C D E F

SARCOPTERYGII

ACTINOPTERYGII


Characteristics

Possess a braincase (differentiates from tunicates and cephalochordates)

Other synapomorphies

Neural crest

Complex sense organs & cranial nerves

Muscularized gut wall, differentiated digestive organs

Respiratory gills, heart, and hemoglobin

Muscles to draw in water for feeding & respiration



Chondrichthyes

Osteichthyes

Sarcopterygii

Actinopterygii

Vertebrates

CR

AN

IATE

S

Hagfishes

Vertebrates

Lampreys

Gnathostomes (possess jaws)

- Chondrichthyes (cartilaginous fishes)

- Osteichthyes (bony fishes)

Sarcopterygii (lobe-finned fishes)

Actinopterygii (ray-finned fishes)


Hagfishes (Myxiniformes)

Most “primitive” of living or fossil craniates

Sister group of all other craniates

~50 species, all marine

No larval stage

Benthic scavengers, lack jaws

Possess 1 semi-circular canal

Lack paired fins & vertebrae


Hagfishes

Vertebrates

Lampreys







Vertebrates

Possess vertebrae

At least 2 semi-circular canals

Radial fin muscles



Chondrichthyes

Osteichthyes

Sarcopterygii

Actinopterygii

Vertebrates

CR

AN

IATE

S

Hagfishes

Vertebrates

Lampreys







Lampreys (Petromyzontiformes)

~40 species described

Found in marine & freshwater

Larval stage (ammocoete) filter-feeds from sediments in streams (~3 years)

Most species parasitic as adults (use of rasping tongue); other species do not feed as adults

Sea Lamprey (Petromyzon marinus)


Hagfishes

Vertebrates

Lampreys







Gnathostomes (Gr., gnathos = jaw + stoma = mouth)

Possess jaws

3 semi-circular canals

2 sets of paired fins

Paired nostrils

5 gill slits

Gill arches


Hagfishes

Vertebrates

Lampreys








Chondrichthyes

Osteichthyes

Sarcopterygii

Actinopterygii

Vertebrates

CR

AN

IATE

S

Chondrichthyes (Gr., chondros = cartilage + ichthyos = fish)

Calcified cartilaginous skeleton (calcium salts form prismatic plates – tesserae Latin “tile”)

Placoid scales – tooth-like with dentine and enamel or enamel-like covering

Males possess claspers; inserted into cloaca of female for internal fertilization

Teeth continuously replaced or bony plates grow continuously


Elasmobranchii (Gr., elasmos = thin plate + branchia = gills)

Includes sharks, skates, and rays

~800 species

Mostly marine, some truly freshwater

Smallest – dwarf lantern shark, largest – whale shark

Thin plates of connective tissue that bear the gills

Rays separated from sharks by their enlarged pectoral fins; grow forward and fuse to head during ontogeny

Chondrichthyes

Elasmobranchii (sharks, rays, and skates)

Chondrichthyes

Holocephali (Gr., holos = whole + kephale = head)

Chimaeras or ratfish

~30 speceis

Marine, mostly deepwater

Single gill opening

Males have a spiny clasper-like organ on head to grab female during copulation

Venomous predorsal spine

Chondrichthyes

Hagfishes

Vertebrates

Lampreys







TELEOSTOMI

Teleostomi (Gr., teleos = terminal + stome = mouth)

Includes Acanthodi (extinct) and Osteichthyes (bony fishes)

Terminal mouth

Bony operculum

Branchiostegal rays

Osteichthyes (Gr., osteon = bone + ichthyes = fishes)

The bony fishes

~29,000 species

Well-ossified (bony) skeleton

Lungs (eventually gas/swim bladder)


Osteichthyes

Hagfishes

Vertebrates

Lampreys








Chondrichthyes

Osteichthyes

Sarcopterygii

Actinopterygii

Vertebrates

CR

AN

IATE

S

Sarcopterygii (Gr., sarkodes = fleshy + pteryg = wing or fin)

Fleshy or lobe fin fishes

Includes living and extinct fish-like forms and the terrestrial vertebrates

Marine and freshwater forms

Lobe fins – supported by bones and muscle outside body

Enamel on teeth


Coelacanths (Actinistia)

One genus Latimeria (2 species)

Strictly marine, inhabits depths 500-2300 feet

Intracranial joint – joint in head that increases gape

Believed to have been extinct until one was discovered in 1938 of east coast of South Africa

Multiple morphologies in fossil record

“Living fossil” current form ~400 mya

Sarcopterygii

Coelacanths (Actinistia)

Sarcopterygii

Latimeria chalumnae Rebellatrix sp.

Lungfishes (Dipnoi)

Once classified as amphibians – tetrapods?

Freshwater tropical* rivers and lakes

Swim or crawl on bottom with lobed fins

Tooth plates for crushing food

African lungfish (Protopterus, 4 species)

South American lungfish (Lepidosiren paradoxa)

Australian lungfish (Neoceratodus forsteri)

Sarcopterygii

Lungfishes (Dipnoi)

African lungfishes

Order: Lepidosireniformes

Family: Protopteridae

Genus: Protopterus

Sarcopterygii

Lungfishes (Dipnoi)

South American lungfish

Order: Lepidosireniformes

Family: Lepidosirenidae

Species: Lepidosiren paradoxa

Sarcopterygii

Lungfishes (Dipnoi)

Australian lungfish

Order: Ceratodontiformes

Family: Ceratodontidae

Species: Neoceratodus forsteri

Sarcopterygii


Evolution of various apomorphies

General group characteristics

Adaptations to various environments

Summary

biology of fishes env 422/nre 422/eeb440 · construct a cladogram that includes the following...

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