Myxinoidea
SYNAPOMORPHES
- Integumentary mucous glands
- Accessory hearts in liver and tail region
- Complex, protrusible mouthparts and a protrusible ‘tongue’
Petromyzontoidea
SYNAPOMORPHES
- Single, blind-ended nasohypophyseal opening on top of head
- axial arcualia
- ammocoetes larva
Chondrichthyans
SYNAPOMORPHES
- primary perichondral and endochondral mineralization patterns
- placoid scales
- teeth with complex multi-cusped pattern
- teeth whorls responsible for replacement pattern
- paired fins with triangular basals and parallel series of radial cartilages
Holocephali
SYNAPOMORPHES
- gill arches beneath braincase
- pectoral fin with two main basal elements
- dorsal fin articulates with cranial elements of axial skeleton
Elasmobranchii
SYNAPOMORPHES
- extrabranchial cartilages on hyomandibula only
- right and left coracoids fused
- teeth with ‘aprons’
Batoidea
SYNAPOMORPHES
- cornea attached directed to eye - no upper eyelid
- palatoquadrate lacks articulation with neurocranium
- cervical vertebral centra just caudal to chondrocranium fused into a tube (synarcual)
- antorbital cartilage directly or indirectly joins propterygium of pectoral girdle and nasal capsule of chondrocranium
Galeomorphii
SYNAPOMORPHES
- Closed lateral line canal
- Ethmoid region of chondrocranium downcurved
- Nasal groove present
Osteichthyes
SYNAPOMORPHES
- Dermal marginal mouth bones with rooted teeth
- Lepidotrichia
- Presence of lung or swimbladder embryonically derived from gut tube
Actinopterygii
SYNAPOMORPHES
- basal elements of pectoral fins enlarged
- median fin rays attached to skeletal elements that do not extend into fin
- single dorsal fin
- scales with unique interlocking mechanism
- scales histologically distinctive, with complexly-layered ganoine
Polypteridae
SYNAPOMORPHES
- Unique dorsal fin spines
- facial bone fusion
- unique pectoral fin structure
Acipenseriformes
SYNAPOMORPHES
- opercle reduced
- elongate caudal extension of presphenoid
- body scaling reduced to tiny isolated elements, or absent
Acipenseridae
SYNAPOMORPHES
- Presence of the five longitudinal rows of bony scutes along trunk
- presence of long, snout fin spine along leading edge of pectoral fin
- presence of plate-like supraorbital with a preorbital descending process
- rostral canals curve lateral to barbels
- supracleithrum tightly joined to, and forms part of, the dermal skull roof
- presence of a cardiac shield (right and left clavicles fused ventrally)
Polyodontidae
SYNAPOMORPHES
- series of very elongate dorsal median rostral and ventral median rostral bones with cylindrical cross sections
- Uniquely-shaped subopercle with a caudally-pointing fan of rod-like ossifications
Abdominal pelvic fins
fins are ventrally located toward the rear of the fish
thoracic pelvic fins
fins are located just ventrally to the pectoral fins `
jugular pelvic fins
pelvic fins are located more cranially on the ventral surface than the pectoral fins
gonopodium
anal fin of some teleosts is modified into this structure and is used in mating. The females of the same species have a normal anal fin here. Grooved intermittent organ
anguilliform locomotion
Seen in flexible, extended fishes. Whole body is flexed into lateral waves for propulsion. Often, the median fins of these fishes are fused and form a continuous dorsal-caudal-anal fin.
subcarangiform locomotion
undulation of the body that is less than one full wavelength but more than half of a wave length
carangiform
body is thrown into a shallow wave of less than one half of a wave length within the body length. Fishes that use this type of swimming typically have fusiform bodies, a narrow caudal peduncle and a large forked caudal fin
ostraciform locomotion
propulsion is mainly caused by the caudal peduncle. Does not provide much speed but fishes who use it typically have armor
fin swimming
achieved by the undulation of individual fins or fin pairs. Great deal of maneuverability. Can be used as primary or secondary mode of locomotion
placoid scales
- These scales are plate-like, with an upward and
caudally directed “cusp” known as a dermal denticle. - covered by a substance known as vitrodentine. - elasmobranchs
ganoid scales
only present in gars and sturgeons
These are rhombic or diamond-shaped scales, the outer surface of which is composed entirely of a thick layer of enamel (ganoine)
