Vertebrate Zoology Chapters 8 & 9 Osteichthyes PDF

Osteichthyes Chapters 8 & 9 https://urldefense.com/v3/__https://www.cnn.com/202 4/09/24/science/video/octopus-hunt-with-fish-and- punch-digvid?cid=ios_app__;!!AfrVn5rO!xgHFub- 9xkaYvx1MkKjkUFW89bP6K3vHfnvd2XQt8_SPQqvUq9kK 5vgOQsXUG5EBXjWmHjqkB3yZSNZCA6izUec$ Chapter 8 Simplified Phylogeny of Oste...

Osteichthyes Chapters 8 & 9 https://urldefense.com/v3/__https://www.cnn.com/202 4/09/24/science/video/octopus-hunt-with-fish-and- punch-digvid?cid=ios_app__;!!AfrVn5rO!xgHFub- 9xkaYvx1MkKjkUFW89bP6K3vHfnvd2XQt8_SPQqvUq9kK 5vgOQsXUG5EBXjWmHjqkB3yZSNZCA6izUec$ Chapter 8 Simplified Phylogeny of Osteichthyans  ~ 96% of all extant fishes, Osteichthyes and new species are described at a rate of ~ 100/year (largest radiation of extant vertebrates) 2 subclasses: Actinopterygii and Sarcopterygii ~ 42 orders Fossil record: Devonian (400 – 360 MYA) to present Wide range of morphological & physiological adaptations, body sizes, & life histories  Osteichthyan Characteristics Skeleton usually 3 types of dermal Have true enamel on Tail is usually ossified (endochondral scales (ctenoid, cycloid, the outside of their homocercal bone) or ganoid) scales Operculum always Have dermal bones Brain with enlarged present – lateral Lung or swim bladder that extend onto the optic lobes (olfaction adduction pulls H2O branching from palate, and often have reduced relative to thru mouth & into esophagus teeth on the palate sharks) pharyngeal chamber Fins supported by Branchiostegal rays Have teeth many rays (bone or on the floor of the gill embedded in their cartilage) made of Complex muscles chamber that aid with dermal marginal mouth jointed bones called breathing and suction bones lepidotrichia feeding Major Groups of Osteichthyes Actinopterygii Sarcopterygii Ray-finned fish Lobe-finned fish Largest number of aquatic fish All terrestrial vertebrates evolved from this group Basal Actinopterygians Paleonisciformes Mostly from the Devonian and Carboniferous Had thick bony scales Cladistia Includes extant Polypteriformes Bichirs and reedfish Heavy scales with a layer of ganoine Have paired ventral lungs Chondrostei Includes extant Acinpenseriformes Sturgeons and paddlefishes Dermal head bones made of cartilage No vertebral centra Non-respiratory gas bladder Neopterygii Holostei Teleostei Lepisosteiformes (Gars) Most extant fishes Amiiformes (Bowfin) Contains more species than any other lineage of vertebrates Chapter 9 – Where We Are Going… Actinopterygians: Ray-Finned Fish Non-Teleosts Polypteriformes Lepisosteiformes Amiiformes Teleosts Osteoglossomorpha Elopomorpha Otocephala Euteleostei Swimming Fins Body Shapes Reproduction Habitats Heterothermal Fishes Sarcopterygians: Lobe-Finned Fish Effects of Human Activities  Non-Teleosts Subclass Cladistia, Order Polypteriformes – Bichirs and Reedfish Sister group to Actinopterii Ganoid scales Possess both gills and lungs Live in stagnant freshwater habitats in Africa Bichirs are ambush predators Reedfish feed on snails and invertebrates Morphological significance in the evolution of this clade – extremely limited jaw mobility & small-to-modest gape Ganoid Scales Acipenseriformes – Non-Teleosts Scute External bony plate on the surface of fish Protective function against environmental abrasions and predation Holostei – Non-Teleosts Teleosts 95% of extant ray-finned fishes Entire genome was duplicated in the common ancestor to all teleosts Doubled number of chromosomes and DNA content Most have 48-50 chromosomes Number of Hox genes would have also been doubled Four extant clades – Osteoglossomorpha, Elopomorpha, Otocephala, and Euteleostei Jaws – premaxillae and maxillae are not attached to the skull and protrude when mouth is open Homocercal tails Osteoglossomorpha Clade (“bony tongue”) – Teleost Clade Most primitive of extant teleosts Example is Arawana whose upward curved mouth allows them to feed at the surface Elephantnose electric fish use weak electrical fields to detect objects at night or in murky water; conductive objects cause the lines of force to converge, whereas a nonconductive object causes them to diverge  Eels, bonefishes, and tarpons Elopomorpha Clade Leptocephalus larvae Eel larvae dispersed by ocean currents (marine fish) – Teleost Many eels are catadromous - migrate Clade from freshwater to saltwater to breed Otocephala – Teleost Clade Clupeomorpha (herrings, shads, sardines, and anchovies) Silvery Mostly marine Feed on plankton Some are anadromous - migrate from seawater to freshwater to spawn Ostariophysi (catfish, milkfish, carps, suckers, minnows, tetras, and pirhanas) 80% of freshwater fish and 25-30% of all fish species Most have protrusible jaws and pharyngeal teeth Have a Weberian apparatus (modified vertebral elements that transmit sound vibrations from gas bladder to inner ear) that increases their ability to hear Synapomorphy is an alarm substance (pheromone) released from the skin when damaged  More than 17,500 Euteleostei – Teleost Clade extant species Ancestral body plan might be like a salmonid Salmon, trout, pikes Perciformes (perch-like fish) have over 10,000 species Have a wide range of body types depending on habitat and feeding strategy Why Are Teleosts So Diverse? List three possible factors that contribute to this diversity. 1. Jaws 2. Body Shape 3. Fins Teleost Jaws Have a mobile upper jaw (protrusible) Useful for suction feeding Have a movable premaxilla and corresponding modifications in the jaw musculature which make it possible for them to protrude their jaws outwards from the mouth The premaxilla is unattached to the cranium Protrudes from the mouth and creates a circular opening This lowers the pressure inside the mouth, sucking the prey inside The lower jaw and maxilla are then pulled back to close the mouth, and the fish is able to grasp the prey https://fishlab.ucdavis.edu/category/fish-feeding/ https://www.youtube.com/watch?v=pDU4CQWXaNY https://www.youtube.com/watch?v=m2lcBaqYK1o&NR=1  Teleost Jaws Pharyngeal jaws Mobile tooth plates that are fused together and to gill arches around the esophagus Moray eels grasp prey in their teeth, then move their pharyngeal jaws into their mouths to drag prey into their throats https://www.youtube.com/watch?v=CTprtO8091Y Some Teleost Body Plans Fish Body Shapes Rover Predator Streamlined and fusiform Pointed head, forked tail, fins distributed evenly around the body (stability and maneuverability) Constantly moving and searching out prey, they capture prey after a short pursuit Faster species tend to have more deeply forked tails and narrow caudal peduncles (e.g. tuna and swordfish ) Slower species, such as salmon, tend to have less deeply forked tails Their prey are typically smaller and slower Maneuverability instead of high speed may be more important Ambush Predator Fusiform, but have very long bodies (torpedolike or arrowlike) Fish Body Shapes Barracuda and needlefish (salt water) and gars and pikes (freshwater) Lie relatively still, waiting for prey to swim by Ambush the prey with a fast strike The caudal fin is usually large and often rounded, and the dorsal and anal fins are placed far back on the body (often in-line with each other) for extra thrust from a low or stopped speed Head may be somewhat flattened with a large mouth in a long-pointed snout filled with teeth Viewed from the front, these fish have a small cross section and are not readily obvious as "big fish" to their potential prey Also tend to have cryptic coloration that allows them to blend in with their background Fish Body Shapes Surface-Oriented Usually smaller Have mouths that point up, flattened heads, large eyes, and a dorsal fin placed posteriorly Adaptations to feeding on small insects, plankton, or smaller fish at the water's surface Examples: Killifish, four-eyed fish, flying fish, and halfbeaks  Fish Body Shapes Bottom Fish Bottom rovers have rover-predator-like shapes, also have barbels, flattened heads, and protrusible mouths (goatfish and catfish) Bottom clingers are fish that usually have flattened heads, large pectoral fins, pelvic fins modified to cling (or suction-cup) to the substrate (gobies and sculpins) Flatfish are laterally flattened and lie on one side with mouths and eyes that have changed positions (flounders and halibut) Fish Body Shapes Deep-Bodied Fish Laterally compressed (flattened from side to side) and have deep bodies (dorso-ventrally elongated) Dorsal and anal fins are often relatively long, the pectoral fins are placed high up on the body, and the pelvic fins have moved forward to a position beneath the pectoral fins Designed for rapid turning and maneuvering in tight quarters, such as coral reefs, rocks, eelgrass or seaweed beds Not extremely fast Often have stiff spines in their fins for additional protection against predators Example: Perch Fish Body Shapes Eel-Like Fish Long snakelike form Blunt or rounded heads, small or absent pectoral and pelvic fins, and reduced (or rounded and small) caudal fins If present, the dorsal and anal fins may be elongated with the body Good at hiding or foraging for prey in tunnels, crevices, tight spaces between rocks or coral, or burrowing in soft bottoms Teleost Fins Pelvic Fins Ventral and toward the posterior in more ancestral bony fish (e.g. salmon and carp) Most of these fish have rover- predator body shapes, and the fins assist with braking and steering More anterior in more derived teleosts Below the pectoral fins, or sometimes in front of them In bottom-dwelling fish, they are often modified into organs that hold onto the substrate Teleost Fins Pectoral Fins Chondrichthyes need them to create lift, but bony fish don’t Generally flexible and mobile and have a diversity of shapes, sizes, and positions Can be specialized for food gathering, courtship, sound production, walking, and gliding as well as turning and braking High up on the sides of deep-bodied fish Toward or below the midline in rover-predator fish https://www.cnn.com/2024/09 Slower-moving have rounded fins that help with stability /26/science/sea-robins-walk- taste-seafloor?cid=ios_app Long and pointed in very fast rover-predator fish (tuna) Broad, rounded, ventral, and spread out laterally in fish that sit on the bottom (suckers and sculpin) Teleost Fins Dorsal and Anal Fins Very long on rover-predators and deep-bodied fish to provide stability In fast-swimming pelagic fish (e.g. tuna and mackerel) the rearmost portions of the fin are frequently broken into numerous finlets Forward portion of the dorsal fin may fold into a dorsal slot when swimming fast to reduce resistance Bony fish without that specialization will collapse dorsal and anal fins and fold in pectoral and pelvic fins during bursts of speed Teleost Fins Caudal Fin Shape is related to swimming speed Most bony fish have a homocercal tail Fastest-swimming fish (tuna and marlin) have a stiff, quarter-moon- shaped fin attached to a narrow caudal peduncle Deep-bodied fish and most surface and bottom fish have tails that are square, rounded, or slightly forked Sturgeon have a heterocercal tail like sharks Teleost Fins Adipose Fin Fleshy, dorsal appendage found in trouts, smelts, lanternfish, and catfish Located between the dorsal and caudal fins Long considered to be non-functional More recently, research suggests that the adipose fin may serve as a “precaudal flow sensor” to improve maneuverability in turbulent water  Axial muscles arranged in “w” Swimming shaped bands called myomeres Each myomere attaches across several vertebrae, and the muscle fibers are short in each, so contractile length is short but produces a lot of power and precise control (because many myomeres are involved in bending a given section of the body) Anterior-to-posterior sequential contractions of the muscles on one side of the body with simultaneous relaxing of muscles on the other side of the body  Swimming Study of movement easiest in slow-swimming, flexible fish like an eel: Serpentine; waves of contraction move from mid- section to posterior, by alternate contractions of myomeres on each side Each wave is amplified as it moves back, so that posterior bends more widely Bending of body pushes laterally against water, producing a reactive force that is directed forward but at an angle; this force has 2 components: thrust – overcomes drag & propels fish forward lateral force – makes head “yaw” off course (worse in some species than in others)  Fast swimmers are less flexible, & bend mostly in caudal Swimming region Caudal region is smaller, often much smaller, than trunk region which holds most muscle mass, & tendons transfer most force from the large muscles to the caudal peduncle This form of swimming is best developed in tunas, swordfishes, sailfishes, & some pelagic sharks (Mako shark) All have homeothermic regulatory capacity The “swept-back” sickle-shape of the caudal fins in these fishes provides a high “aspect ratio” to the fin surface Aspect ratio = Dorsal-to-ventral height/anterior-to- posterior length  Types of Movement Anguilliform - Very flexible fish (eels); full wavelength Carangiform - Movement mostly in caudal region; less than half of a wavelength Ostraciiform - Inflexible body; movement only in caudal fin Labriform - Use pectoral fins for movement Rajiform - Sine waves along elongated pectoral fins Amiiform - Sine waves along dorsal fin Gymnotiform - Sine waves along anal fin Balistiform - Sine waves along dorsal and anal fins Reproduction As a clade, teleost fishes have a greater variety of reproductive modes and life-history strategies such as size/age at maturity, fertilization (internal vs external), parity (oviparous, ovoviviparous, viviparous), clutch size, egg size, placement of clutch, developmental rates, etc. than any other clade of vertebrates Reproduction - Ovaparity Freshwater Habitats Care for yolk-rick demersal eggs; males often guard nests +/- young Marine Habitats Release large numbers of small, buoyant, transparent eggs Develop and hatch in the open sea Terrestrial Habitats Grunions, mudskippers, and rockhopper blennies lay eggs on land  Reproduction - Viviparity Rare in fish (˂3%) Occurs in Poeciliidae Guppies, mollies, platys, swordtails, etc. Also occurs in sea horses Males generally carry fertilized eggs during gestation Sex Determination in Teleosts  Protandry Start as males and change to females Clown anemone fish live in pairs or small groups Largest individual is female and smaller is male; any smaller individuals will remain immature If the female dies, the male changes to a female Maximizes fitness  Protogyny Start as initial phase males and females; then change to terminal phase males Bluehead wrasse Terminal phase males defend territories and mate the most; initial phase males can mate but do so in groups by intercepting females  Can be simultaneous Other Reproductive (functional ovaries & testes) or sequential Methods - Hermaphroditism Rare in fish Egg traders (alternate male/female roles during single mating session) Reciprocating monogamous pairs (alternate roles between breeding sessions) Harem polygynous species (initially simultaneous, change to male later) Other Reproductive Methods - Parthenogenesis Parthenogenesis – form of asexual reproduction which includes gynogenesis and hybridogenesis Gynogenesis Diploid egg is activated by sperm, but it doesn’t fertilize it Mollies Other Reproductive Methods - Parthenogenesis Hybridogenesis Male DNA enters the egg, but it gets eliminated during meiosis Minnows Deep Sea Fishes Major issues encountered No light – light doesn’t penetrate deeper than 1,000m Very little food – without light no photosynthesis so dependent on falling detritus Mesopelagic Fishes Mesopelagic fish move closer to the surface at night to feed, then go deeper into the water during the day Possess large, upward- directed eyes to detect prey silhouetted by light above Bathypelagic Fishes Stay in the deep ocean Have light organs to attract prey; photophores “Naked retinas” increase sensitivity Large mouths and stomachs Deep Sea Creatures Exhibit Bioluminescence | Blue Planet | BBC Earth - YouTube Coral Reef Fishes  Similar to sharks, these fish are Heterothermal Fishes able to keep parts of their bodies warm (regional heterothermy) Includes mackerels, tunas, and billfishes No heat producing tissues but instead use retia to warm brain, muscles, and viscera; have myoglobin-rich (red) muscles Opah only fish to warm its entire body Heat production by pectoral muscles; body is insulated by fat layer; countercurrent retia in gill arches Sarcopterygii Actinistia Coelacanths 2 derived characteristics: A first dorsal fin that is supported by a plate of bone but lacks an internal lobe A symmetrical 3-lobed tail Only 1 extant family: Latimeridae 2 species of the genus Latimeria Vestigial lung (fat) Sarcopterygii Dipnoi Lungfish Paired lungs Lost premaxilla, maxilla, and dentary Fused teeth on their palate that form tooth ridges that crush hard prey Dominant freshwater radiation during the Devonian 3 extant families, each with a single genus 1 in each of South America, Africa, and Australia All extant forms are restricted to slow- flowing tropical or subtropical rivers or swamps characterized by very low DO  Lungfishes continued The 2 obligate air-breathers (Lepidosiren & Protopterus) are capable of prolonged estivation – they burrow into mud on bottom as water levels drop, secrete a thin mucous “cocoon” at the bottom of a burrow chamber, decrease metabolic activity, and can survive 4-6 months until rains replenish the water level (physiologically, this is the hot weather equivalent of hibernation to avoid winter extremes) Human Impacts on Fishes Freshwater fish are threatened by pollution, draining, damming, canalization, and diversions Marine fish are threatened by over harvesting Large sport fish such as tuna have relatively few offspring and take a long time to reach maturity Fish farming can cause feces and food to accumulate and allow parasites such as sea lice to proliferate and spread to wild fish