Modified dorsal fins
Caudal fin shapes
A - rounded
B - truncate
C - emarginate
D - forked
E - lunate
F - heterocercal
G - abbreviate heterocercal
H - homocercal
I - isocercal
Diphycercal
Pectoral fin variation
Pelvic fin variation
Thunniform
Compressiform
Depressiform
Anguilliform
Filiform
Taeniform
Sagittiform
Gl bif
Globiform
Placoid scales are covered
with enamel and are found in
chondrichthyans - vertebrate
teeth are derived from placoid
scales
Ganoid scales have an
enamel-like covering called
ganoine
i - found
f d in
i gars andd
relatives
Cosmoid scales are covered
with cosmoine and are found
in coelocanths
Cyloid and ctenoid scales are
also called elasmoid - They
are thin
thi andd flexible
fl ibl andd are
found in most bony fishes
Fin rays have a left and right
h lf andd usually
half
ll have
h
a
segmental structure
“True”
True fin spines originate
as a single bony element
Fin rays and spines articulate
with pterygiophores at their
bases
Fish skeleton can be divided in axial (skull and vertebral column)
and appendicular
pp
((fins))
Vertebral structure varies
b
between
abdominal
bd i l andd
caudal region - has centrum
and neural arch - has hemal
arch in the tail and ribs
(pleural, epipleural, epineural,
epicentral) in the thorax
Teleost skulls are complex - combination of bones that form the
neurocranium (protection of the brain) and branchiocranium (the
jaws, gills and supporting structures)
Shark skull
is entirely
g
cartilage
neurocranium
and
branchiocranium
Teleost neurocranium - a combination of bone types chondrocranium ((endochondral)) and dermatocranium ((dermal)) dermatocranium consists mostly of bones on the outer surfaces
Endochondral bone
originates as cartilage that
is replaced by bone
dermal bone does not
originate as cartilage
branchiocranium – consist of 5 arches – mandibular, palatine,
hyoid,
y , opercular
p
and branchial
mandibular – form upper jaw original palatoquadrate – the original upper jaw of sharks is
entirely inside the mouth of the teleost,
teleost on the roof as the palatine
the original lower jaw (Meckel’s cartilage) is small, and lies
within the dentary
new dermal bones
form the functional
upper jaws –
premaxilla, maxilla,
and supramaxilla
- the
th first
fi t two
t may
bear teeth, but in more
advanced fishes, only
the premaxilla bears
teeth
Branchiocranium mandibular arch - Meckel
Meckel’ss cartilage lies within the dentary
palatine arch – consists of palatine bone on roof of mouth
hyoid arch – (suspensorium) – attaches lower jaw and opercular
apparatus to the skull - consists of the hyomandibula, the
symplectic, and quadrate
opercular apparatusbones that form the
operculum –
opercle,
l subopercle,
b
l
preopercle,
interopercle,
p
hyoid complex –
part of hyoid arch 5 bones that lie inside
th lower
the
l
jaw
j andd
opercular bones
glossohyal supports the
tongue
branchial arch – four pairs of gill arches that support the gills
basibranchials hypobranchials
basibranchials,
hypobranchials, ceratobranchials
ceratobranchials, epibranchials
epibranchials,
pharyngobranchials, upper pharyngeal bones
Found in most chondrichthyans
and all actinopterygians
Found in primitive sharks
Found in sarcopterygians
and tetrapods
Appendicular skeleton
Adaptive radiation in Lake Malawi cichlidae
telencephalon – olfactory (I)
diencephalon – pineal gland – sensitive to light, regulates diurnal cycling and homeostasis
mesencephalon – vision (II)
metencephalon
t
h l – muscular
l movementt - with
ith cerebellum
b ll
(III – IV)
myelencephalon – integration of somatic and visceral functions –homeostasis (V-X)
Cranial Nerves
I - olfactory
II - optic - retina
III - oculomotor
III, IV, VI - eye muscles
IV - trochlear
VII & VIII - lateral line on head
VI - abduscens
V - trigeminal - jaw and face
VII - facial
f i l
VIII - acoustico
IX - glossopharyngeal - gill region
X - vagus - lateral line of body & viscera