Chapter 9 Flashcards
what is the snout of a fish called? how does it change from primitive to derived teleosts?
ethmoid region. Circumborbital bones get lost or fused in derived teleosts
how does the caudal region change between primitive and derived teleosts?
loss in the caudal skeleton: loss of hypurals
what are some other characteristics that get lost in derived teleosts?
loss of fin rays, brachiostegal rays, vertebrae.
how many branchiostegal rays, vertebrae, pelvic fin rays an caudal fin rays are there in derived teleosts?
Branchiostegal rays: 7
Vertebrae: 24
Pelvic fin rays: I-5
Caudal fin rays: 17
what is a general rule for the ratio of caudal and abdominal vertebrae in derived teleosts?
roughly the same amount
what is the ratio of caudal and abdominal vertibrae in highly derived teleosts?
twice as many caudal vertebrae
TRENDS OF LOSS AND REDUCTION OF PARTS (TELEOST TRENDS)
1) SHIFT IN POSITION OF PAIRED FINS
2) DEVELOPMENT OF SPINES, PARTICULARILY DORSAL, ANAL AND PELVIC
3) SHIFT IN FUNCTION OF JAW BONES AND DEVELOPMENT OF ASCENDING PROCESS
four major groups of living teleosts
osteoglossomorpha, elopomorpha, clupeomorpha, euteleostei
THREE SUBORDERS OF OSTEOGLOSSOMORPHA
OSTEOGLOSSOIDEI, NOTOPTEROIDEI, MORMYROIDEI
WHAT DEFINES OSTEOGLOSSOMORPHA?
FEEDING MECHANISM: GLOSSOHYAL PLATE MAKES CONTACT WITH TEETH ON MEDIAL BONE CALLED PARASPHENOID!
Elopomorphas contain what two orders
Elopiformes, anguilliformes
most diverse group of the primitive teleosts
anguilliformes
how does anguillidae differ from all other families in its order?
catadromous
Where do the eels breed?
Sargasso sea
what connects tarpons(elopomorpha) to anguiliformes?
leptocephallic larvae
