Cartilaginous Fishes Flashcards
(87 cards)
1
Q
class of jawed fishes with cartilaginous skeleton
A
chondrichthyes
2
Q
what does the class chondrichthyes include
A
- sharks
- rays
- skates
- chimaeras
3
Q
two main subclasses of chondrichthyes
A
- Elasmobranchii
- Holocephali
4
Q
sharks, rays, skates, sawfish
A
Elasmobranchii
5
Q
chimaeras, aka ghost sharks
A
Holocephali
6
Q
no of orders under chondrichthye
A
13 orders
7
Q
no of families under chondrichthye
A
60 families
8
Q
no of genus under chondrichthye
A
198 genera
9
Q
no of species under chondrichthye
A
1193
10
Q
Divisions under Subclass Elasmobranchii
A
Superorder
1. Batoidea
2. Selachii
11
Q
under Superorder Batoidea
A
Rajiformes or Hypotremata
12
Q
under Super order Selachii
A
- Squaliformes or Pleurotremata
- Other sharks
13
Q
manta rays
A
Myliobatiformes
14
Q
great white shark
A
Carcharodon carcharias
15
Q
general size
A
5-16 ft
16
Q
general body shape
A
- fusiform - sharks
- flattened body shape - typical of rays
17
Q
coloration pattern where the dorsal side is darker, and the ventral side is ligher, helping with camouflage
A
countershading
18
Q
general eye characteristics
A
- positioned laterally in sharks
- dorsally in batoids
19
Q
general nostril characteristics
A
ventrally positioned external nostrils
20
Q
general fin characteristics
A
- median and paired fins present, supported by fin rays
- pectoral fin rigid
- pelvic fin have claspers (male)
- heterocercal
21
Q
upper lobe is longer than the lower lobe
A
heterocercal
22
Q
general mouth characteristics
A
- ventral with jaw present
- may have labial folds or furrows
23
Q
general teeth characteristics
A
- modified, enlarged placoid scales
- replaceable rows
24
Q
when did modern fishes likely evolve
A
455 million years ago (Ordovician Period)
25
placoderms gave rise to what
1. Chondrichthyes
2. Osteichthyes
26
where did sharlike forms appeared initially
freshwater
27
freshwater sharks with nearly symmetrical tail, spiny projections, and claspers in males
Pleurocanthodii
28
- marine sharks with double-jointed jaws and no claspers
- possibly ancestors or modern sharks
Cladoselachii
29
- had sharp front teeth for seizing prey
- flat back teeth for crushing mollusks, representing an intermediate step toward modern sharks
Hybodontii
30
caused major decline in chondrichthyes
Permian extinction
31
when most modern shark, skate, and ray families had evolved
Late Cretaceous
32
when did cartilaginous fishes appear
~450 million years ago
33
important fossil species
1. Cladoselache (400 million years ago)
2. Stethacanthus (345-280 m ago)
3. Xenacanthus
34
torpedo-shaped, multiple gill slits
Cladoselache
35
anvil-shaped first dorsal fin
Stethacanthus
36
freshwater predator with V-shaped teeth and long skull spine
Xenacanthus
37
one of the largest sharks in history
Carcharodon megalodon
38
Elasmobranchii:
notochord
replaced by cartilaginous vertebrae
39
Holocephali:
notochord
intact (not replaced)
40
Elasmobranchii:
jaw structure
upper jaw not fused to cranium
41
Holocephali:
jaw structure
upper jaw fused to cranium
42
Elasmobranchii:
gill slits
5-7 externl, uncovered
43
Holocephali:
gill slits
4 gill slits, covered by an opercullum
44
Elasmobranchii:
skin
placoid scales or naked
45
Holocephali:
skin
no scales in adults, except in clasper regions
46
Elasmobranchii:
mouth size
wide
47
Holocephali:
mouth size
small
48
Elasmobranchii:
digestive system
spiral valve in the intestine
49
Holocephali:
digestive system
fused stomach and intestine
50
Elasmobranchii:
tail movement
- heterocercal tail
- thrusting
51
Holocephali:
tail movement
- thin long tail
- flapping pectoral fins
52
Elasmobranchii:
reproductive features
males have claspers
53
Holocephali:
reproductive features
some have frontal claspers
54
Elasmobranchii:
special organs
- electric organs (Torpedo)
- poison stings (Trygon)
55
Holocephali:
special organs
none
56
- gill slits covered
- upper jaw fused to skull
Holocephali
57
gill slits exposed
Elasmobranchii
58
gill slits on undersides
Batoidea
59
gill slits on sides
Selachii
60
Orders under Elasmobranchii
1. Carcharhiniformes
2. Carcharhiniformes
3. Heterodontiformes
4. Hexanchiforme
5. Lamniformes
6. Orectolobiforme
7. Pristiophoriformes
8. Rajiformes
9. Rhinopristiformes
10. Torpediniformes
11. Myliobatiformes
12. Squaliformes
13. Squatiniformes:
61
ground sharks
Carcharhiniformes
62
bullhead sharks
Heterodontiformes
63
cow sharks and frilled sharks
Hexanchiformes
64
mackerel sharks
Lamniformes
65
carpet sharks
Orectolobiformes
66
saw sharks
Pristiophoriformes
67
common rays and skates
Rajiformes
68
guitarfishes, wedge fishes, and sawfishes
Rhinopristiformes
69
electric and thornback rays
Torpediniformes
70
stingrays
Myliobatiformes
71
sleeper sharks and dogfish sharks
Squaliformes
72
angel sharks
Squatiniformes
73
Orders under Holocehpali
1. Chimaeriformes
2. Callorhinchiformes
74
characterized by a single gill slit covered by a soft operculum, a long, slender body, and a venomous spine on the dorsal fin
Chimaeriformes (true chimaeras)
75
- species with a long, trunk-like snout that gives them their unique appearance
- mostly found in southern oceans
Callorhinchiformes (elephant fish)
76
- gill slits lateral
- spiracles present
- heterocercal tail
Selachii (sharks)
76
fusiform body, five to seven gill slits, small spiracles
Squaliformes (dogfish sharks)
77
- flattened dorso-ventral body
- gill slits ventral
- pectoral fins fused to head
Batoidea (rays and skates)
78
- large pectoral fins fused to head
- spiracles functional
Rajiformes (skates and rays)
79
- single gill opening with fleshy operculum
- no spiracles, cloaca, or scales
- jaws with tooth plates
Holocephali (chimaeras)
80
- pleurotrematic elasmobranchs
- mostly marine, found in tropical warm waters
- known for muscular strength, agility, and acute senses
- bottom dwellers, feed on crustaceans and mollusks
dogfishes
81
largest group of cartilaginous fishes
sharks
82
largest shark
whale shark
83
- hypotrematic elasmobranchs
- body flattened dorso-ventrally, large pectoral fins fused to head
skates and rays
84
- long rostrum with sharp tooth-like scales
- swings saw to disable prey
- can grow 3-6 meters
sawfish (Pristis)
85
somewhat shark-like body
guitarfish (Rhinobatus)
86
- deep-sea
- grotesque apperance, long tapering tail
- gill slits covered by operculum
- jaws fused to skull
- flat tooth plates for crushing mollusks
- open lateral line system
- males have additional cephalic clasper
Chimaeras (Ratfish, ghost fish)
