Chapter 6 - Major Radiation of Fishes Flashcards Preview

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Flashcards in Chapter 6 - Major Radiation of Fishes Deck (25):


- Endochondrial bone - bone that develops from cartilage

- Operculum - bony gill covering that prevents backflow


Synapomorphies of Actinopterygii

- Parallel arrays of closely packed radial bones support the base of the fins

- Single dorsal fin

- Scales composed of ganoine (glassy, multilayered, mineralized tissue)


Order Polypteriformes - Birchir and Reedfish

- The most basal lineage of extant Actinopterygii
- Elongate, heavily armored fishes from Africa
- Flag-like dorsal finlets with spines
- Fleshy bases of pectoral fins
- Modified heterocercal tail
- Ganoid scales - shiny, enamol-like surface
- Well-ossified skeleton (ossify - to turn into bone)
- Paired ventral lungs


Clade Actinopteri

- Includes all actinopterygii, except the order Polypteriformes

- Synapomorphy for clade

- Swim bladder derived from lung


Order Acipenserformes - Derived Characters

- Endochondrial bone absent


Order Acipenserformes - Family Acipenseridae (Sturgeons)

- Large, active benthic fish
- Teeth absent in adults
- Five rows of enlarged armor-like scales along the body
- Reduced dermal skeleton
- Heterocercal tail armored with specialized series of scales
- Protrusible jaws


Order Acipenserformes - Family Polyondontidae (Paddlefish)

- Even greater reduction of dermal skeleton
- Greatly elongated and flattened rostrum


Synapomorphies of Neopterygians

- Upper pharyngeal teeth consolidated into tooth bearing plates
- Abbreviated heterocercal tail


Primitive Neopterygians - Order Lepisosteiformes (Gar)

- Elongated jaws
- Thick armor
- Needlelike teeth


Primitive Neopterygians - Order Amiiformes (Bowfin)

- Single species Amia calva
- Cycloid scales - thin, pliable scales formed of a thin sheet of bone-like material and underlying tissue
- Mobile maxilla (upper jaw)


Synapomorphies of Telostei

- Premaxilla mobile allows for protrusible jaw and greater suction
- Powerful movable pharyngeal jaws
- Homocercal tail - symmetrical and flexible tail that allows the fish to swim horizontally without using its paired fins
- More diverse paired fins
- Uroneaural - modified posterior neural arches that support the dorsal side
- Thin-scaled or lack scales entirely


Clade Osteoglossomorpha

- Found in tropical freshwaters

- Synapomorphy - Well developed teeth on the parasphenoid (one of the bones comprising the roof of the mouth)


Clade Elopomorpha

- Leptocephalus larva - specialized larva that are adrift currents for a long time
- Most are eel-like and marine


Clade Clupeomorpha

- Specialized mouth and gill straining apparatus for feeding on plankton
- Silvery scales
- Mostly marine schooling fish


Clade Euteleostei

- Vast majority of extant teleost are in the clade Euteleostei
- Nuptial tubercles - structures located on the head, body, or fins that are made of epidermal cells that helps the contact between males and females during mating by providing friction


Superorder Ostariophysi - Weberian Apparatus

Structure composed of small bones called ossicles (ear) that connects the swim bladder to the inner ear


Superorder Ostariophysi - Alarm Substance

Pheromone that is released into the water when the skin is damaged thus causing a fright reaction by nearby members


Superorder Ostariophysi - Adipose Fin

Small, fleshy, rayless fin found posterior to the dorsal fin


Clade Neognathi

- Synapomorphy

- Increased contact of the first vertebrae with the skull bone

- Most basal lineage is the family salmonidae (salmon)


Clade Acanthopterygii - Synapomorphies

- More mobile jaw
- Ctenoid scales - thin scales composed of bonelike material and characterized by a serrated margin


Acanthopterygii - Atherinomorpha (Flying Fish, Grunion, Needlefish, Guppies, and Swordtails)

Protrusible jaw that is modified


Acanthopterygii - Percomorpha (Perches, Sunfish, Cichlids, Flounders, etc.)

Pelvicfins with one spine and five soft rays; pelvic and pectoral girdles are joined


Synapomorphies of Sarcopterygii

- Paired fins with long muscular lobes extending below the body and have a bony central axis
- Pulmonary vein
- Scales made of cosamine (dentine-like material as opposed to enamel-like material)


Subclass Dipnoi

- Autostylic jaw suspension
- Teeth are scattered over the palate and fused into tooth ridges
- Diphyceral tail - tail is continuous with the dorsal and anal fins
- Thin scales embedded into the skin
- Internal lung structure
- Two-chambered atrium
- Pulmonary circulation (blood supply to the lungs)
- Bile salts (where it first evolved)
- Estivation - a period of dormancy that is usually induced by a lack of water. The fish burrow into the mud and metabolism is reduced


Subclass Actinistia

- One living genus Latimeria (Coelocanth)
- First dorsal fin lacks lobe
- Lacks a maxilla
- Curious rostral organ
- Ossified swim bladders that is filled with fat