Vertebrates 5b - Fish integument Flashcards Preview

Vertebrates 305 > Vertebrates 5b - Fish integument > Flashcards

Flashcards in Vertebrates 5b - Fish integument Deck (18)
Loading flashcards...
2

Notable characteristics of fish skin

Many mucous glands = decrease friction, defense (hagfish); granular glands for toxins - lion fish; photophores produce light (chemoluminescent) by enzymes releasing photons as they break down nutrients (bacteria involved)

3

Photophores in species

Flashlight fish can turn on/off for communication by covering with skin; angler uses it as lure

4

Mucous

Bunch of glycoproteins that stick together, serves to lubricate

5

Early scales

Dermal armour (cosmoid plates) in extinct fish; bone in the skin.

6

Structure of dermal armour

Basically a layer of bone: enamel (hard!), cosmine (dentine) and vascular bone. Heavy, not flexible, but super protected.

7

Why did early fish have such intense dermal armour?

Massive invertebrate aquatic scorpion beasts!!

8

Extant fish scales

mainly bone, but thin and overlapping. Develop from dermis, covered in some epidermis with mucous glands.

9

Advantage of overlapping scales in fish?

They can bend better; lighter; still some protection

10

Chromatophores in fish

Just below the dermis, above the subcutis

11

Cosmoid scales

Rare, in actinisia and some dipnoi. Large, contain cosmine (harder).

12

Ganoid scales

In gar pike, bichirs. Thick, rectangular. Ganoine replaces cosmine. More primitive

13

Cycloid and ctenoid scales

Most bony fish. Calcified, overlapping, circular annular layers (grow as fish grow). Very thin. Ctenoid have cteni which help anchor.

14

Info we can get from scales

Get DNA, learn about its envrionment. Annular layers are like tree rings which can give age; Can determine if it was a bad year of growth if smaller.

15

Two groups of ray fins and their scales

Soft ray-finned fishes have cycloid scales, and hard/spiky ray-finned fishes have ctenoid

16

Placoid scales

aka dermal dentricles. In chondrichthyes. Non-overlapping. Similar to teeth and contains pulp cavity, dentine and enamel. Probably degenerate armour.

17

Melanophores in chondrichthyes

At the top of the dermis.

18

Why are placoid scales ok, even tho they provide less protection?

Sharks etc became apex predators, so they have few predators and they can escape anything that might attack.

19

Teeth

Shark teeth are skin derivatives and are very similar to placoid scales.