1. ¿ What anatomical/physiological features distinguish vertebrates?
¿ Who are vertebrates related to, and how are they related to each other ?
¿ In what ecosystems do vertebrates occur ?
¿ What are the roles of vertebrates in aquatic and terrestrial ecosystems ?
¿ How many different kinds or species of vertebrates are there ?

2. The vertebrate story… There are over 57,000 living vertebrate species
For every extant species there were ~100 that are now extinct
Vertebrates are found in almost all environments on earth, from ocean depth to highest mountains and from pole to pole
Vertebrates range in size from tiny fish, amphibians and reptiles small enough to fit on a coin, to blue whales who are so huge their heart is a big a small car
Vertebrate lifestyle is energetically expensive… obtain energy as both carnivores and herbivores with many specializations in between

3. 1) Non-amniotes: The vertebrate story… Two major groups of vertebrates
A-gnathans (Myxinoidea & Petromyzontoidea ) (~100 species)
Chondr-ichthians (~1,000 species)
Osteichthians (~27,000 species)
Amphibians (~6,400 species)

4. Amniotes , which also has two major groups: Sauropsids -
The vertebrate story…
Two major groups of vertebrates…
Amniotes , which also has two major groups:
Sauropsids -
Testudinians (~300 species)
Lepido-saurians (~8,000 species)
Crocodilians (~25 species)
Avians (~9,700 species)
Synapsids –
Mammalians (~4,800 species)

5. ¿How many species are there on planet Earth?
The vertebrate story…
New species…
¿How many species are there on planet Earth?
Estimates vary by an order of magnitude!
Thousands of species described annually
Most are small and of “other” kingdoms… still some vertebrates being described.
Examples…

7. Agnatha Extinct: Ostracoderms *Coverd by bony armor
*Mostly small fish 2cm (some up to 2m)
*Small mouth openings
*4 openings on dorsal surface of head
*Extinct after abundance of jawed fishes on the scene

8. Agnatha Extant: “Cyclostomes” Hagfish and Lamprey
*Are not as closely related as might appear
*Hagfish are scavengers that lack the rasping denticles of lamprey
*Most Lamprey are parasitic

9. Agnathans are a Polyphyletic group!
Extant Jawless fishes…
Agnathans are a Polyphyletic group!
Super class Agnatha (oldest craniates in fossil record) Cambrian or earlier
Most abundant in Silurian and lower Devonian
Fossil fish small <15cm (although some up to 2m)
Sucking or scooping feeding mechanism
Conodonts resemble hagfish (Cambrian to Triassic)
All gill tissue is endodermal in origin
Gill structures, arteries, nerves etc. internal to branchial skeleton

10. Hagfish (Myxinoidea) … Class - Myxini Order – Myxiniformes
Extant Jawless fishes…
Hagfish (Myxinoidea) …
Class - Myxini Order – Myxiniformes
Family – Myxinidae
Genera – 6 from mostly temperate waters
Species - > 40 with Pacific and Atlantic Hagfish most well known.
At least one fossil representative from Carboniferous that resembles modern species.
Only occur in marine habitats
Live on soft bottoms of mud,
silt or clay usually from 25 – 600m deep.

11. Hagfish (Myxinoidea) …
Extant Jawless fishes…
Hagfish (Myxinoidea) …
They burrow and perhaps feed on soft-bodied worms etc. they encounter.
Also scavenge and prey on fish Apparently good sense of smell, as they quickly find netted fish.
Unique “knotting” technique allows
them to pull meat from carcass.
Eversion and retraction of teeth
on each side of mouth
pull off/in food

12. Hagfish (Myxinoidea) …
Extant Jawless fishes…
Hagfish (Myxinoidea) …
Eyes degenerate and covered by skin
Large tentacles surround nasal opening and mouth
Probably lack a larval stage

13. Hagfish (Myxinoidea) …
Extant Jawless fishes…
Hagfish (Myxinoidea) …
5 to 15 pairs of gills (depending on species)
Some species have branchial ducts that exit via a single tube and external opening
Broad-gilled Hagfish
Broad-gilled Hagfish

14. Hagfish (Myxinoidea) …
Extant Jawless fishes…
Hagfish (Myxinoidea) …
Cartilaginous skeleton not well developed… * No vertebrae * Only a membranous roof of the skull
1 semicircular canal on each side of head (Lamprey have 2 and other vertebrates have 3)
In addition to primitive heart… they also have contractile vascular regions in: * Tail * Cardinal vein
* Portal vein
Have red blood cells like other vertebrates… but only one type of WBC.

15. Hagfish (Myxinoidea) …
Extant Jawless fishes…
Hagfish (Myxinoidea) …
Females outnumber males 100 to 1
Thought at first to be hemaphroditic
Almost nothing known of their reproductive biology!
Recent studies have verified the presence of neural crest cells.

16. Hagfish (Myxinoidea) …
Extant Jawless fishes…
Hagfish (Myxinoidea) …
Well known for a defensive mechanism… SLIME!
Abundant mucous glands secreting mucus and coiled proteins
Proteins straighten in water and trap mucus close to hagfishes body
After danger has left, hagfish ties a knot in tail and pulls it towards its head “squeegie-ing” off the slime.

17. Hagfish (Myxinoidea) …
Extant Jawless fishes…
Hagfish (Myxinoidea) …
Some commercial use in Asia as source
for leather and meat.
Can cause some
Economic loss to
commercial fisheries
when able to
access fish
caught in gill nets
and/or long lines
“Human exploitation
Of natural resources,
such as fisheries, typically depletes
stocks because no attention is given
to the biology of the resource and its
renewable, sustainable characteristics.
For example, we do not know how long
Hagfish live; how old they are when
they first begin to reproduce; exactly how, when or where they breed; where the youngest juveniles live; what are the diets and energy requirements of free-living hagfishes; or virtually any of the other information needed for good management. As a result, eel-skin wallets will probably become as rare as items made of whalebone , tortoise shell and ivory. “(Pough et al , pg. 59)

18. Lamprey (Petromyzontoidea) … Class – Cephalaspidomorphi
Extant Jawless fishes…
Lamprey (Petromyzontoidea) …
Class – Cephalaspidomorphi
Order – Petromyzontiformes / (Hyperoartia)
Family – Petromyzontidae
Genera – 10
Species - ~ 40 with Petromyzon sp. and Lampetra sp. most well known.
Superficially resemble Hagfish, but differ in several important ways including vertebrae
Unique in having a nasal opening (single) that leads to the pituitary gland.

19. Lamprey (Petromyzontoidea) …
Extant Jawless fishes…
Lamprey (Petromyzontoidea) …
Petromyzon marinus Sea Lamprey

20. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …
Most species are parasitic
Use hornified “teeth”
on the surface of the oral hood and tongue
Can have a negative
Impact on game
and commercial
fisheries

21. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …
Lampreys have 7 pairs of gill pouches
Do not typically use flow-through ventilation
Rather, they use tidal ventilation

22. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …
Nearly all species are anadromous
Anadromous species that grow in adult form in the sea are the largest (up to 1m)
A small parasitic species (Lampetra minima) was full grown at less than 10 cm (now extinct)
Spawn in streams
Lay 100,000s of eggs

23. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …
Larval lamprey are called ammocoetes
Live in gravel beds filtering plankton and organic debris for 3-7 years
Metamorphose and then begin journey to sea or other major water basin where they will grow and mature.
Usually live as adults for less than 2 years.
They migrate back up to their hatching grounds (now spawning grounds)
Mate and then die!

24. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …

25. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …

26. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …

27. Lampreys (Petromyzontoidea) …
Extant Jawless fishes…
Lampreys (Petromyzontoidea) …

28. Gnathostomes 3 groups appeared in the Paleozoic:
1) Placoderms (ex. Arthrodires) had large boney plates and paired fins

29. Gnathostomes 3 groups appeared in the Paleozoic:
2) Chondrichthyans (cartilagenous fishes) *Includes sharks, rays, skates, and ratfish
*Cartilaginous skeletons
*Many with placoids
*No bony operculum

30. Gnathostomes 3 groups appeared in the Paleozoic:
3) Teleostomes (spiny and bony fishes)
*Acanthodians are (spiny fishes) are extinct
*Had skeleton of bone and cartilage
*Had an operculum

31. Osteichthyans Shared ancestors with tetrapods Have an air sac
Dermal bone
Paired fins… either ray finned (actinopterygii) or fleshy finned (sarcopterygii)

32. Actinopterygii Basal groups include Sturgeon and Paddlefish

33. Actinopterygii
Advanced groups include Gars, Bowfins and Teleosts (most other bony fish)

34. Sarcopterygii
Have fleshy lobed fins, internal nares and a bony operculum
2 major clades:
Actinistians, extinct except “coelocanths”
Rhipidistians (and dipnoi) “lungfish”

35. Amphibia *Paraphyletic group… omitting amniote descendants
*Extinct groups include Labrynthodonts (Ichthyostega)
*Extant group (Lissamphibia) includes:
Apoda (caecilians)
Urodela (salamanders)
Anura (frogs)

36. Amniotes Group includes Reptiles and Synapsids Reptilia (paraphyletic)
Chelonia (testudinea) “turtles”
Rhynchocephalians “tuatara”
Squamates “lizards, snakes etc.”
Crocodylians “crocodiles” etc.
Aves “birds”

37. Synapsids
Amniotes with synapsid skull, hair, mammary glands & nipples (most)

38. Mammalia
Monotremata

39. Mammalia
Marsupialia

40. Mammalia
Insectivora

41. Mammalia
Xenarthra

42. Mammalia
Tubulidentata

43. Mammalia
Pholidota

44. Mammalia
Chiroptera

45. Mammalia
Primates

46. Mammalia
Lagomorpha

47. Mammalia
Rodentia

48. Mammalia
Carnivora

49. Mammalia
Pinnipedia

50. Mammalia
Perissodactyla

51. Mammalia
Atriodactyla

52. Mammalia
Hyracoidea

53. Mammalia
Proboscidea

54. Mammalia
Sirenia

55. Mammalia
Cetacea