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)

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)

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)

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

‘O’opu hi’ukole (Lentipes concolor)

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

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

Osteichthyes - Actinopterygii - Chondrostei: bichirs

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

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

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

Osteichthyes - Actinopterygii - Chondrostei: paddlefishes:

Osteichthyes - Actinopterygii - Chondrostei: paddlefishes: 2 living species, one NA one Chinese largely scaleless elongate snouts (36 - 52% of total length) filter feeds, snout covered with electroreceptors to detect swarms of zooplankton

Osteichthyes - Actinopterygii - Neopteryigii : bowfin:

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

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)

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

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

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

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

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

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

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…