vertebrae zoology

Osteichthyes
In this module, we will dissect the perch, a member
of Osteichthyes, Actinopterygii, and Teleostei.
Yellow perch FWS 1.jpg by Otis Maha/U.S. Fish and Wildlife Service is in the public domain
Osteichthyes
Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer.
Osteichthyes
“Oste” = bone
“Ichthyes” = fish
Osteichthyes includes all bony vertebrates (not just fish!)
and are split into two clades: Sarcopterygii and
Actinopterygii.
Major traits for Osteichthyes
1. Endochondral bone: replaces cartilage during
development
2. Gas bladder: derived from the gut; ancestrally, this
evolved as a lung or lungs for breathing air. It was later
modified to form a buoyancy control device (gas or swim
bladder) in the Actinopterygii.
1. Endochondral bone
Coleman, W. M. (1921).
Beginners Zoology.
MacMillan.
2. Gas
bladder
Note: The
gas bladder
is often
torn like
this upon
dissection.
Sarcopterygii
Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer.
Sarcopterygii
“Sarx” = flesh
“Pteryx” = fin
Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer.
Lung Fish Fins.jpg by Patty Jansen is in the
public domain
Sarcopterygii includes all vertebrates with fleshy, lobelike limbs. The major extant groups include coelacanths
(Actinistia), lungfish (Dipnoi), and tetrapods.
The major trait in this group is the presence of paired
fins that are “fleshy” (lobed) and have a bony central
axis.
Ray-finned fishes (Actinopterygii)
Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer.
Actinopterygii
“Actina” = ray
“Pteryx” = fin
Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer.
Yellow perch FWS 1.jpg by
Otis Maha/U.S. Fish and
Wildlife Service is in the
public domain
Actinopterygii includes all fish with bony or
horny projections (“rays”) connected by a thin
web of skin. The most extant species within this
clade are in Teleostei.
The major trait in Actinopterygii is the presence
of these ray fins as opposed to the fleshy lobed
limbs of Sarcopterygii.
Teleostei
Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer.
Teleost fish (Teleostei)
Major trait = Operculum
The operculum is a bony covering
that protects the gills.
Rapid expansion creates negative
pressure and allows fish to ‘suck’ in
prey items.
Opercular pumping aids respiration
(don’t have to be swimming rapidly
to move H2O over gill filaments).
Underneath the
operculum…
Gill filaments: where
gas exchange occurs
Gill rakers: protect
the delicate gill
filaments from food
and other particulates
passing through the
pharynx
Gill (branchiostegal)
arches: support the
gill filaments and
rakers
External Anatomy
• Branchiostegal rays – support the floor of the
opercular chamber
• Maxilla – upper jaw bone; acts as a lever for the jaw
muscles in helping to protrude the premaxilla (upper
jaw bone) forward and the mandible (lower jaw bone)
downward; participates in “gulping” action for sucking
in prey
• Naris – opening that allows water to flow into the
olfactory sacs
• Lateral line – senses pressure and vibrations
• Anus – exit for intestinal excreta
• Urogenital aperture – exit for urinary and reproductive
excreta
Digestive System
• Pharynx – opening inside the mouth that acts as both leads
to the esophagus and contains the internal gill structures
• Esophagus – tube carrying food to stomach
• Stomach – chemical digestion
• Small intestine – nutrient absorption
• Pyloric ceca (singular: cecum) – extensions of the intestine
that secrete digestive enzymes and add extra surface area
for nutrient absorption
• Pancreas – secretes digestive enzymes and some hormones
(e.g. insulin); note: will not be visible in perch specimens
• Liver – stores energy, metabolizes waste, breaks down
toxins (like alcohol), produces blood clotting factors, and
produces bile
• Gallbladder – stores and secretes bile to break down fats
Urogenital System
• Kidney – removes nitrogenous waste from blood
for temporary storage in urinary bladder and
eventual excretion into urogenital aperture
• Urinary bladder – temporary storage for
nitrogenous waste before exit through the
urogenital aperture
• Testes (male) – produce sperm
• Ovaries (female) – produce eggs/ova
Cardiovascular System
Deoxygenated blood from the body enters the sinus
venosus and fills the atrium which empties the blood
into the muscular ventricle. The ventricle pumps
blood through the bulbus arteriosus to the gill
capillary beds to become oxygenated then the body
tissues to distribute the oxygen.
Two chamber heart.svg by
Ahnode CC BY SA 3.0
Other Structure-Function Relationships
• Spleen – produces white blood cells, destroys old
red blood cells
• Transverse septum – thin membrane separating
the head/heart cavity from the body cavity
Perch Anatomy Terms List
External Anatomy
Branchiostegal rays
Lateral line
Naris
Operculum
Anterior dorsal fin
Pectoral fin
Pelvic fin
Anal fin
Posterior dorsal fin
Caudal fin
Anus
Urogenital aperture
Gallbladder
Liver
Esophagus
Transverse septum
Pharynx
Intestine
Pyloric ceca
Testes
Ovaries
Sinus venosus
Atrium
Ventricle
Bulbus arteriosus
Internal Anatomy
Gill filaments
Gill arches
Gill rakers
Swim bladder
Kidney
Urinary bladder
Spleen
Stomach

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