Chapter 5

Question 1

what two abilities are hagfish renowned for?

Answer 1

tie themselves in a knot, large amounts of slime

Question 2

are hagfish highly fercund?

Answer 2

no. very few eggs, no larval phase

Question 3

what aquatic habitats do lampreys live in?

Answer 3

anadromous/fresh water

Question 4

which of the two familys of jawless fish are semelparous?

Answer 4

Lampreys

Question 5

what is the lamprey’s larval stage called?

Answer 5

ammocete

Question 6

similarities btwn hagfish and lampreys:

Answer 6

• they lack jaws
• they lack gill arches
• single median nostril
• lack paired fins
• lack bone
• cartilaginous internal skeleton

Question 7

what is the most primitive of all fishes?

Answer 7

hagfish

Question 8

what are some features that lampreys share with all other vertebrates, and that seperates them from hagfish?

Answer 8

• 2 or 3 semicircular canals
• well developed neural and haemal arches
• true neuromast organs along the lateral line
• extrinsic eye muscles
• nervous regulation of the heart
• capable of hyper osmoregulation

Question 9

What is the common name for ‘Chondrichthyes’?

Answer 9

cartilaginous fishes

Question 10

Squatina

Answer 10

Angel sharks

Question 11

what are morphological characters of the three groups of chondrichthyes?

Answer 11

i) Cartilaginous skeleton
ii) Dermal skeleton of denticles (their scales)
iii) airbladder absent
iv) spiral valve in the intestine
v) internal fertilization (claspers)
vi) osmoregulation by retention of urea

Question 12

what are the two most diverse groups of sharks?

Answer 12

Carcharhiniformes and Squaliformes

Question 13

elasmobranchs

Answer 13

sub group of chondrichtheyes, seperating sharks and rays from ratfist

Question 14

Order Rajiformes, most important morphological features:

Answer 14

i) pec fins are fused to the head over the gill openings

ii) attachment or articulation of the pectoral girdle to the vertebral column

Question 15

what seperates skates from other rays?

Answer 15

skates are the only rays that lay eggs (OVIPAROUS)

(thought to be sister group of guitar fishes)

• paired electric organs along side of tail
• claw-like spines along lateral extremes of disc

Question 16

Order Pristiformes: what is the common name?

Answer 16

sawfishes VIVIPAROUS

Question 17

how are the toothed rostrum different between sawfish and sawshark (family pristidae)?

Answer 17

sawshark have irregular teeth, whereas sawfish are regularly placed teeth on their snout. VIVIPAROUS

Question 18

Order Torpediniformes: who are they?

Answer 18

torpedo or electric rays, tropical to temperate. Distinguished by huge electric organs along the lateral margin of the disc. stun prey, defend against attack by predators. VIVIPAROUS

Question 19

Order Rhinobatiformes: who are they?

Answer 19

guitarfishes. VIVIPAROUS, specialized in their gill arches. body ranges from shark-like to ray-like. Benthic

Question 20

Order Miliobatiformes: who are they?

Answer 20

stingrays, eagle rays, manta rays, cownose.

• most considered specialized for active swimming
• some considered epipelagic
• pec fins firmly attached to spine by ‘ball and socket’ arrangement

Question 21

Former Order Dasyatiformes: who are they?

Answer 21

stingrays. member of Myliobatiformes. VIVIPAROUS. serrated spine at base of tail

Question 22

what is a Holocephali?

Answer 22

infraclass of chimeras, relatives to sharks and rays. exist under the order of chondrichthyes.

Question 23

what defines chimeras from the rest of em?

Answer 23

i) large, permanent, slow growing tooth plates
ii) upper jaw is fused to the cranium
iii) they have only one single gill opening