1. Osteichthyes Osteichthyes - bony fish Origin
First fossils Late Silurian
Two major lineages diverged in Devonian
Actinopterygii (ray-finned fishes)
Sarcopterygii (lobe-finned fishes; gave rise to tetrapods)

2. Osteichthyes General characteristics
Characteristics of Osteichthyes
mouth bones with rooted teeth
Bony fin rays supporting fins
Fully calcified body skeleton
Dermal armor reduced to thin, interlocking scales
1) elasmoid type
2) ganoid (gars)
3) cosmoid (Sarcopterygii)

3. Osteichthyes General characteristics
Characteristics of Osteichthyes
mouth bones with rooted teeth
Bony fin rays supporting fins
Fully calcified body skeleton
Dermal armor reduced to thin, interlocking scales
1) elasmoid type
2) ganoid (gars)
3) cosmoid (Sarcopterygii)

4. Osteichthyes General characteristics
Bony operculum covers single gill opening
Lung or swim bladder derived from gut present in most (all?)

6. ‘O’opu hi’ukole
(Lentipes concolor)

8. Osteichthyes - Actinopterygii
General characteristics of Actinopterygii
Pectoral fin with enlarged basal elements,
elements supporting fin rays don’t extend into fin
single dorsal fin

9. Osteichthyes - Actinopterygii
Major Groups within Actinopterygii
1) Chondrostei = “primitive”including bichirs, sturgeons, and paddlefish
2) Neopterygii = “modern” fish
Neopterygii contains….
bowfins and gars “primitive”
Teleostei ( teleosts) includes most fish

10. Osteichthyes - Actinopterygii - Chondrostei:
bichirs

12. Osteichthyes - Actinopterygii - Chondrostei:
Chondrostei: bichirs reedfish, and Sturgeon

16. Osteichthyes - Actinopterygii - Chondrostei:
Chondrostei: bichirs, reedfish, sturgeons
Sturgeon
: ~ 27 species
Europe, Asia, NA;
many anadromous
bottom feeders (but not scavengers),
fleshy barbels below jaw search bottom sediments for food
unique rows of bony plates along body
largest fresh-water fish = beluga sturgeon (Huso huso)
8 m and 2,865 lbs!
most famous of caviar sturgeons

20. Osteichthyes - Actinopterygii - Chondrostei:
sturgeon swim bladder used to produce isinglass
sheet of almost pure gelatin used for glues, waterproofing, and clarifying white wine

21. Osteichthyes - Actinopterygii - Chondrostei:
paddlefishes:

26. Osteichthyes - Actinopterygii - Chondrostei:
paddlefishes:
2 living species, one NA one Chinese
largely scaleless
elongate snouts ( % of total length)
filter feeds, snout covered with electroreceptors to detect swarms of zooplankton

27. Osteichthyes - Actinopterygii - Neopteryigii :
bowfin:

29. Osteichthyes - Actinopterygii - Neopteryigii :
gars: 7 species; mostly freshwater eastern NA
elongated snout
ganoid scales
nostrils at tip of “beak”
lurking ambush predators
dorsal and anal fins displaced to posterior to increase thrust

32. Osteichthyes - Actinopterygii - Neopteryigii - Teleostei
Teleostei = teleost fish: includes all other ray finned fish
@ 20,800 species worldwide
Found in every type of aquatic habitat
Two largest groups:
a) catfish & minnows: (over 6,000 species)
b) perches: 7,800 species)

34. Osteichthyes - Actinopterygii - Neopteryigii - Teleostei
Trends in Neopterygian evolution
increasing locomotor efficiency
swim bladder for precise buoyancy regulation
Homocercal caudal fin
fins no longer need to control lift, can be folded to body reducing drag and can be modified to serve other functions
dermal armor reduced to thin scales - reduces weight, increases flexibility
increased complexity and efficiency of feeding apparatus (face, jaws, skull)
mobile, tooth-bearing pharyngeal jaws
highly protrusible jaws provide very strong , directional suction for feeding from a variety of directions
mouth can close while buccal cavity still expanded

35. Osteichthyes - Actinopterygii - Neopteryigii - Teleostei
mobile jaws, fine motor control permits delicate movements and manipulation – (jaws become like our hands)
Some highly specialized for deep-sea environment
deep-sea species generally adopt “low energy” habits
(little long-distance movement, sit-and-wait predation)
Stomach hugely distensible
Most have bioluminescence produced by photophore organs; this can serve to
1) lure prey
2) identify species and gender

36. Osteichthyes - Sarcopterygii
Sarcopterygii = lobe-finned fishes - ancestor of tetrapods
Two modern groups:7 living species
Dipnoi = lungfish

38. Osteichthyes - Sarcopterygii
Sarcopterygii = lobe-finned fishes - ancestor of tetrapods
Two modern groups:7 living species
Dipnoi = lungfish
Coelocanthimorpha = coelocanth

39. Osteichthyes - Sarcopterygii
Characteristics of Sarcopterygii:(Lungfish & Coelocanth)
Fleshy pelvic and pectoral fins with single basal skeletal element, central supporting elements, muscular lobes
Lungfish strictly freshwater, found in Africa, South America , Australia
African and SA species, gills reduced; breathe air only; Australian retains functional gills
African and SA species live in shallow waters, aestivate in dry season;
Australian lives in more open waters, can only survive limited periods of moderate desiccation

40. Osteichthyes - Sarcopterygii
Coelocanth
Found off South Africa, Mozambique, Madagascar; Indonesia
prefer deep, cold waters
grow to about 6', 140 lbs
ovoviviparous

43. Osteichthyes - Conservation
US alone, ~ 20% of 800 species of native freshwater fish currently facing significant threat
Worldwide problem is probably greater
Marine fish - Data mostly about commercially valuable fish
Overfishing
Coral reefs are being destroyed (mined for limestone, blown up or poisoned by people collecting for pet trade...)
Coral reefs are dying for other reasons – e.g., increasing water temperature has caused large-scale deaths of some reefs world wide
Coelocanth rescue…