DOCSLIB.ORG

Lobe Finned Fish

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Lobe Finned Fish Fish What is a Fish? •Phylum: Chordata •Subphylum: Vertebrata •Key Features: • Aquatic vertebrates • Paired fins - movement • Scales - protection • Gills – gas exchange • Endoskeleton – made of bone or cartilage Evolution of Fishes •Fish where the first vertebrates •They arose from a common ancestor with Lancelets or Tunicates •First fish were small and jawless • Some developed heavy armored plates. •They evolved in the late Cambrian period •The Age of Fishes – Devonian period •Key Features of the Evolution of Fish: • Jaws • Paired fins Jaw Evolution •Evolved from jointed Gill arches. Gill arches used for support of the gills. Gill arch attached to cranium forming top jaw. The joint/hinge created a lower jaw. First used to prevent backflow of water over gills. Allowed to hold on to prey. • Jaws increase the food options for fish. • Jaws allow for muscle attachment and true teeth. • Jaws allow for defense. Evolution of Fishes • Paired pectoral and pelvic fins developed at same time as jaw. Allowed for more control in movement. • Tail is used for thrust and propulsion in the water. The combination of jaws and paired fins allowed for more complex movement for attack and evasion. • Cartilage is flexible tissue that supports the body and is softer than and more flexible than bone. • Modern fish groups: • Sharks • Jawless fish • Bony fish – two groups – lobe fined and ray fined fish Form and Function • Key feature: • Adaptation to aquatic life included various modes of: • Feeding • Specialized structures for gas exchange • Paired fins for locomotion • Feeding • All modes of eating are seen in fish. • From carnivores to parasites • The movement of food: • Mouth – esophagus – stomach – pyloric ceca – intestine – out anus • Other organs that aid in digestion – liver and pancreas • Excretion • Two ways to remove ammonia: • Diffusion through gills • Kidneys – excretory organ that filters wastes from the blood. • Waste removed as urine Form and Function •Respiration • Gills are used for gas exchange • Covered in Boney fish by Operculum • Made of feathery, thread like structures called filaments • Contain a network of fine capillaries that provide a large surface area for exchange of O2 and CO2. • Countercurrent flow – blood flows in opposite direction of water flow. Increases the O2 exchange. • Process: 1. O2 rich water enters mouth. 2. Water moves over gills filaments 3. O2 poor water out of openings on side of pharynx. Form and Function •Circulation • Fish have a closed circulatory system • Two chambered heart • Single loop circulatory system. • Heart has 4 parts • Sinus venosus • Atrium – (Chamber) • Ventricle – (Chamber) • Bulbus Arteriosus Form and Function •Response • Well organized nervous system • Parts of Fish Brain: • Olfactory bulb – smell (olfaction) • Cerebrum – Fish smell – other verts – voluntary functions • Optic lobe – sight • Cerebellum – coordination • Medulla Oblongata – functions of many internal organs Form and Function Lateral Line System Sensitive receptors along body used to detect movement in the water. • Most fish active at Daytime • Well developed Eye Ampullae of Lorenzini Senses electrical currents in water Found in sharks and their relatives. Form and Function •Movement •Fish move by alternating paired sets of muscles on either side of the backbone. •Forms an S – shape •Fins are used for stabilization in the water and control course and direction. Swim Bladder Swim bladder is an organ that adjusts buoyancy. Found in Bony fish. Fish are denser than water which means they would sink if not for swim bladder. Relax-air in-float Muscles tighten-air out-sink Sharks and relatives use large oil-filled liver for buoyancy. Lift is generated by swimming. •Reproduction • Both internal and external •Oviparous • Eggs laid and hatch outside the body of female. • Ex: Salmon •Ovoviviparous • Eggs are retained in body after internal fertilization • “Born Alive” • Ex: Guppies •Viviparous • Live birth – mother attached to offspring – no egg – Mammals • No fish examples Form and Function • Integuments • Skin covered with scales -Thin, round disks of highly modified bone that grow from pockets of skin -Overlap like roof shingles, all pointing toward tail to minimize friction Grow during entire life of fish -Adjusting growth pattern to food supply • Scales grow quickly when food is abundant and slowly when scarce • Skin contains pigmented chromatophores -Create various color patterns Form and Function Some Types of Fish Scales: • Ganoid – found in Gars, diamond-shaped, shiny, and hard. • Placoid – found in sharks and relatives. Structure similar to teeth. • Leptoid – found in high order bony fish. As they grow form concentric rings. Overlapping- head to tail (roof tiles). Less drag. • Two types of Leptoid scales • Cycloid – smooth outer edges. Primitive fish with soft fin rays. • Salmon and carp • Ctenoid – toothed outer edges. Advanced fish with spiny fin rays. • Bass and crappie Ganoid Scales Placoid scales Cycloid scale Leptoid Scales Ctenoid scale Body Plan Body Plan •Jawless Fish •Oldest Class of vertebrates •Lack true teeth and Jaws and Paired Fins •Skeleton made of cartilage •Keep notochord during life •Agnatha •Contains Lampreys and Hagfish Lamprey • Class: Cephalospidomorphi • Long and slender w/ no paired fins. • Filter feeds as larva. • Parasite as adult. • Can live in Fresh and Salt water • Breed in rivers and lakes but move into sea as adults Feeding process: Attaches to organism with suction cup mouth. Use strong, rasping tongue and toothlike structure to scrape skin away. Sucks up blood, tissue and body fluid. Hagfish Class: Myxini Pinkish gray, wormlike body w/ four or six short tentacles around mouth Feeds on dead or decaying fish, may eat from inside out Called Slime Eels Peculiar Traits Creates a lot of slime that suffocate prey Ties itself into knots Cartilaginous fishes Sharks and their Relatives • Class: Chondrichthyes • Skeletons made of cartilage • Tooth like scales – sandpaper like • Skates, Rays, Sawfish, Chimaera • ~ 760 species • Ventral mouth • Dermal denticles • Called living fossils Two types: • Holocephalans • Chimaeras- • Elasmobranchs • All other sharks and relatives Holocephalans Chimaeras- • HAVE SKIN OVER GILLS LIKE AN OPERCULUM • TAKE WATER THROUGH NOSTRILS AND OUT OF GILLS Shark Characteristics • Elasmobranchs • Teeth most notable feature for sharks. • Acute olfactory senses-2/3 of cells in the brain used for smell • Nictitating membrane over eye • Gills not protected (Gill Slits) Shark Characteristics Pectoral Fins (Bernouli’s Principle) and oily liver for lift Continue to swim for oxygen and lift (Nurse shark exception) Lateral Line System and AMPULLAE OF LORENZINI Largest Fishes Whale Shark (60 ft) and Basking Shark (60 ft) both are filter feeders DIGESTION • TAKES CHUNKS OF PREY, NO CHEWING • SPIRAL VALVE-aids in digestion by adding surface area OSMOREGULATION • RETAIN UREA (maintains solute concentration equal or greater than sea water • RECTAL GLAND AND GILLS GET RID OF EXCESS SALT • SOME SHARKS CAN GO INTO RIVERS REPRODUCTION • Claspers insert into cloaca for internal fertilization SHARKS MAY BE: • OVIPAROUS (Lay eggs; Mermaid’s Purse) • VIVIPAROUS (Live young) • OVOVIVIPAROUS (internal eggs and live birth) RAYS VS. SKATES • Flat bodied bottom dwellers (Demersal) • Gill slits on ventral side of body • Wing-like pectoral fins • Stingrays have stinging barbs at base of tail • Electric Rays= up to 220 volts with organs on head • Skates don’t have whip tail or sting, and have wave-like motion with pectoral fins instead of flapping Bony Fish • Class: Osteichthyes • Skeleton made of calcified bone • Two groups • Sarcopterygii – Lobe finned fish – lungfish and Coelacanth • Actinopterygii – Ray finned fish – all other fish Most fish are bony (98%); half of all vertebrates Bony skeleton Cycloid (round) scales Operculum (gill cover) Terminal mouths Swim bladder (pressure and lift) Maneuverable fins Subclass sarcopterygii (lobe-finned) • Coelacanths (thought to have been extinct until discovered off the coast of madagascar) Coelacanths are thought to be a link between fish and amphibians because of their lobe fins (homologous structures) Coelacanths have fat-filled swimbladder They are ovoviviparous Jelly-filled rostral organ-electroreceptive Lung fish (have primative lungs instead of swim bladder) Subclass actinopterygii (ray finned fish) • Have ray fins and comprise all fish other than lung fish and coelacanths • Contain a swim bladder • Most diverse and numerous subclass of fish • Body shape directly related to the habitat the fish lives in • Fast fish are hydrodynamic (fusiform body shape; tuna and marlin) • Reef fish are built to turn and maneuver (laterally compressed; butterfly fish and tang) • Flat fish are built for bottom dwelling (flounder) • Some fish are shaped for camo. (Stone fish, pipe fish) Coloration • Chromatophores are color cells (sacks of pigment) • Iridophores reflect light (crystals inside) • Cause fish to look shiny • Colors advertise reproduction, danger, bad taste (poster colors) • Reef fish have cryptic coloration (camo) • Open water fish = obliterative counter shading, darker on the upper side and lighter on the underside of the body Schooling • About 4000 species school as adults • Keep a consistent distance using lateral line • Lateral line is a series of fluid filled pits that sense pressure changes in the water Reproduction • Cartilaginous fish have internal fertilization: claspers are inserted into female cloaca • Cloaca is a common opening for waste and reproduction • Spawning is a fishes fertile time • Sex hormones ready the gametes and fish for spawning • Some are hermaphrodites • Some have sex reversal triggered by hormones turned on by environmental factors, like loss of dominant male or maturity to a certain age or size Migration of Fish •Anadromous – Life cycle goes from salt water to fresh water. • Ex: Salmon and Lampreys •Catadromous – Goes from freshwater to saltwater. • Ex: European Eel.
Load more

Recommended publications
  • A New Stingray from South Africa
    Nature Vol. 289 22 January 1981 221 A new stingray from South Africa from Alwyne Wheeler ICHTHYOLOGISTS are accustomed to the regular description of previously un­ recognized species of fishes, which if not a daily event at least happens so frequently as not to cause great comment. Previously undescribed genera are like­ wise not infrequently published, but higher categories are increasingly less common. The discovery of a new stingray, which is so different from all known rays as to require both a new family and a new suborder to accommodate its distinctive characters, is therefore a remarkable event. A recent paper by P.e. Heemstra and M.M. Smith (Ichthyological Bulletin oj the J. L.B. Smith Institute of Ichthyology 43, I; 1980) describes this most striking ray as Hexatrygon bickelli and discusses its differences from other batoid fishes. Surprisingly, this remarkable fish was not the result of some organized deep-sea fishing programme, but was found lying on the beach at Port Elizabeth. It was fresh but had suffered some loss of skin by sand abrasion on the beach, and the margins of its fins appeared desiccated in places. The way it was discovered leaves a tantalising question as to its normal habitat, but Heemstra and Smith suggest that it may live in moderately deep water of 400-1,000m. This suggestion is Ventral view of Hexatrygon bickelli supported by its general appearance (small eyes, thin black dorsal skin, f1acid an acellular jelly, while the underside is chimaeroids Rhinochimaera and snout) and the chemistry of its liver-oil. richly supplied with well developed Harriota, and there can be little doubt The classification of Hexatrygon ampullae of Lorenzini.
    [Show full text]
  • Phylogeny of a Rapidly Evolving Clade: the Cichlid Fishes of Lake Malawi
    Proc. Natl. Acad. Sci. USA Vol. 96, pp. 5107–5110, April 1999 Evolution Phylogeny of a rapidly evolving clade: The cichlid fishes of Lake Malawi, East Africa (adaptive radiationysexual selectionyspeciationyamplified fragment length polymorphismylineage sorting) R. C. ALBERTSON,J.A.MARKERT,P.D.DANLEY, AND T. D. KOCHER† Department of Zoology and Program in Genetics, University of New Hampshire, Durham, NH 03824 Communicated by John C. Avise, University of Georgia, Athens, GA, March 12, 1999 (received for review December 17, 1998) ABSTRACT Lake Malawi contains a flock of >500 spe- sponsible for speciation, then we expect that sister taxa will cies of cichlid fish that have evolved from a common ancestor frequently differ in color pattern but not morphology. within the last million years. The rapid diversification of this Most attempts to determine the relationships among cichlid group has been attributed to morphological adaptation and to species have used morphological characters, which may be sexual selection, but the relative timing and importance of prone to convergence (8). Molecular sequences normally these mechanisms is not known. A phylogeny of the group provide the independent estimate of phylogeny needed to infer would help identify the role each mechanism has played in the evolutionary mechanisms. The Lake Malawi cichlids, however, evolution of the flock. Previous attempts to reconstruct the are speciating faster than alleles can become fixed within a relationships among these taxa using molecular methods have species (9, 10). The coalescence of mtDNA haplotypes found been frustrated by the persistence of ancestral polymorphisms within populations predates the origin of many species (11). In within species.
    [Show full text]
  • Electrosensory Pore Distribution and Feeding in the Basking Shark Cetorhinus Maximus (Lamniformes: Cetorhinidae)
    Vol. 12: 33–36, 2011 AQUATIC BIOLOGY Published online March 3 doi: 10.3354/ab00328 Aquat Biol NOTE Electrosensory pore distribution and feeding in the basking shark Cetorhinus maximus (Lamniformes: Cetorhinidae) Ryan M. Kempster*, Shaun P. Collin The UWA Oceans Institute and the School of Animal Biology, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia ABSTRACT: The basking shark Cetorhinus maximus is the second largest fish in the world, attaining lengths of up to 10 m. Very little is known of its sensory biology, particularly in relation to its feeding behaviour. We describe the abundance and distribution of ampullary pores over the head and pro- pose that both the spacing and orientation of electrosensory pores enables C. maximus to use passive electroreception to track the diel vertical migrations of zooplankton that enable the shark to meet the energetic costs of ram filter feeding. KEY WORDS: Ampullae of Lorenzini · Electroreception · Filter feeding · Basking shark Resale or republication not permitted without written consent of the publisher INTRODUCTION shark Rhincodon typus and the megamouth shark Megachasma pelagios, which can attain lengths of up Electroreception is an ancient sensory modality that to 14 and 6 m, respectively (Compagno 1984). These 3 has evolved independently across the animal kingdom filter-feeding sharks are among the largest living in multiple groups (Scheich et al. 1986, Collin & White- marine vertebrates (Compagno 1984) and yet they are head 2004). Repeated independent evolution of elec- all able to meet their energetic costs through the con- troreception emphasises the importance of this sense sumption of tiny zooplankton.
    [Show full text]
  • Phylogeny of Basal Tetrapoda
    Stuart S. Sumida Biology 342 Phylogeny of Basal Tetrapoda The group of bony fishes that gave rise to land-dwelling vertebrates and their descendants (Tetrapoda, or colloquially, “tetrapods”) was the lobe-finned fishes, or Sarcopterygii. Sarcoptrygii includes coelacanths (which retain one living form, Latimeria), lungfish, and crossopterygians. The transition from sarcopterygian fishes to stem tetrapods proceeded through a series of groups – not all of which are included here. There was no sharp and distinct transition, rather it was a continuum from very tetrapod-like fishes to very fish-like tetrapods. SARCOPTERYGII – THE LOBE-FINNED FISHES Includes •Actinista (including Coelacanths) •Dipnoi (lungfishes) •Crossopterygii Crossopterygians include “tetrapods” – 4- legged land-dwelling vertebrates. The Actinista date back to the Devonian. They have very well developed lobed-fins. There remains one livnig representative of the group, the coelacanth, Latimeria chalumnae. A lungfish The Crossopterygii include numerous representatives, the best known of which include Eusthenopteron (pictured here) and Panderichthyes. Panderichthyids were the most tetrapod-like of the sarcopterygian fishes. Panderichthyes – note the lack of dorsal fine, but retention of tail fin. Coelacanths Lungfish Rhizodontids Eusthenopteron Panderichthyes Tiktaalik Ventastega Acanthostega Ichthyostega Tulerpeton Whatcheeria Pederpes More advanced amphibians Tiktaalik roseae – a lobe-finned fish intermediate between typical sarcopterygians and basal tetrapods. Mid to Late Devonian; 375 million years old. The back end of Tiktaalik’s skull is intermediate between fishes and tetrapods. Tiktaalik is a fish with wrist bones, yet still retaining fin rays. The posture of Tiktaalik’s fin/limb is intermediate between that of fishes an tetrapods. Coelacanths Lungfish Rhizodontids Eusthenopteron Panderichthyes Tiktaalik Ventastega Acanthostega Ichthyostega Tulerpeton Whatcheeria Pederpes More advanced amphibians Reconstructions of the basal tetrapod Ventastega.
    [Show full text]
  • Biology of Chordates Video Guide
    Branches on the Tree of Life DVD – CHORDATES Written and photographed by David Denning and Bruce Russell ©2005, BioMEDIA ASSOCIATES (THUMBNAIL IMAGES IN THIS GUIDE ARE FROM THE DVD PROGRAM) .. .. To many students, the phylum Chordata doesn’t seem to make much sense. It contains such apparently disparate animals as tunicates (sea squirts), lancelets, fish and humans. This program explores the evolution, structure and classification of chordates with the main goal to clarify the unity of Phylum Chordata. All chordates possess four characteristics that define the phylum, although in most species, these characteristics can only be seen during a relatively small portion of the life cycle (and this is often an embryonic or larval stage, when the animal is difficult to observe). These defining characteristics are: the notochord (dorsal stiffening rod), a hollow dorsal nerve cord; pharyngeal gills; and a post anal tail that includes the notochord and nerve cord. Subphylum Urochordata The most primitive chordates are the tunicates or sea squirts, and closely related groups such as the larvaceans (Appendicularians). In tunicates, the chordate characteristics can be observed only by examining the entire life cycle. The adult feeds using a ‘pharyngeal basket’, a type of pharyngeal gill formed into a mesh-like basket. Cilia on the gill draw water into the mouth, through the basket mesh and out the excurrent siphon. Tunicates have an unusual heart which pumps by ‘wringing out’. It also reverses direction periodically. Tunicates are usually hermaphroditic, often casting eggs and sperm directly into the sea. After fertilization, the zygote develops into a ‘tadpole larva’. This swimming larva shows the remaining three chordate characters - notochord, dorsal nerve cord and post-anal tail.
    [Show full text]
  • Fish Brains: Evolution and Environmental Relationships
    Reviews in Fish Biology and Fisheries 8, 373±408 (1998) Fish brains: evolution and environmental relationships K. KOTRSCHAL1,Ã, M.J. VAN STAADEN2,3 and R. HUBER2,3 1Institute of Zoology, Department of Ethology, The University of Vienna and Konrad Lorenz Forschungsstelle, A±4645 GruÈnau 11, Austria 2Institute of Zoology, Department of Physiology, The University of Graz, UniversitaÈtsplatz 2, A±8010 Graz, Austria 3Department of Biological Sciences, Bowling Green State University, Life Science Bldg, Bowling Green, OH 43403, USA Contents Abstract page 373 Fish brains re¯ect an enormous evolutionary radiation 374 Based on morphology: how conclusions on sensory orientation are reached 376 Structure of ®sh brains 378 Large-scale evolutionary patterns of ®sh brains 384 Functional diversi®cation 386 Cyprinidae Gadidae Flat®shes Cichlidae and other modern perciforms How environments shape brains: turbidity, benthos and the pelagic realms 393 Variation of brain and senses with depth 395 Ontogenetic variation: a means of adaptation? 398 Intraspeci®c variation between `adult' age classes Intraspeci®c variation within age classes Conclusions: where to go from here? 400 Acknowledgements 401 References 402 Abstract Fish brains and sensory organs may vary greatly between species. With an estimated total of 25 000 species, ®sh represent the largest radiation of vertebrates. From the agnathans to the teleosts, they span an enormous taxonomic range and occupy virtually all aquatic habitats. This diversity offers ample opportunity to relate ecology with brains and sensory systems. In a broadly comparative approach emphasizing teleosts, we surveyed `classical' and more recent contributions on ®sh brains in search of evolutionary and ecological conditions of central nervous system diversi®cation.
    [Show full text]
  • Life History Patterns and Biogeography: An
    LIFE HISTORY PATTERNS AND Lynne R. Parenti2 BIOGEOGRAPHY: AN INTERPRETATION OF DIADROMY IN FISHES1 ABSTRACT Diadromy, broadly defined here as the regular movement between freshwater and marine habitats at some time during their lives, characterizes numerous fish and invertebrate taxa. Explanations for the evolution of diadromy have focused on ecological requirements of individual taxa, rarely reflecting a comparative, phylogenetic component. When incorporated into phylogenetic studies, center of origin hypotheses have been used to infer dispersal routes. The occurrence and distribution of diadromy throughout fish (aquatic non-tetrapod vertebrate) phylogeny are used here to interpret the evolution of this life history pattern and demonstrate the relationship between life history and ecology in cladistic biogeography. Cladistic biogeography has been mischaracterized as rejecting ecology. On the contrary, cladistic biogeography has been explicit in interpreting ecology or life history patterns within the broader framework of phylogenetic patterns. Today, in inferred ancient life history patterns, such as diadromy, we see remnants of previously broader distribution patterns, such as antitropicality or bipolarity, that spanned both marine and freshwater habitats. Biogeographic regions that span ocean basins and incorporate ocean margins better explain the relationship among diadromy, its evolution, and its distribution than do biogeographic regions centered on continents. Key words: Antitropical distributions, biogeography, diadromy, eels,
    [Show full text]
  • Sensory Biology of Aquatic Animals
    Jelle Atema Richard R. Fay Arthur N. Popper William N. Tavolga Editors Sensory Biology of Aquatic Animals Springer-Verlag New York Berlin Heidelberg London Paris Tokyo JELLE ATEMA, Boston University Marine Program, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA Richard R. Fay, Parmly Hearing Institute, Loyola University, Chicago, Illinois 60626, USA ARTHUR N. POPPER, Department of Zoology, University of Maryland, College Park, MD 20742, USA WILLIAM N. TAVOLGA, Mote Marine Laboratory, Sarasota, Florida 33577, USA The cover Illustration is a reproduction of Figure 13.3, p. 343 of this volume Library of Congress Cataloging-in-Publication Data Sensory biology of aquatic animals. Papers based on presentations given at an International Conference on the Sensory Biology of Aquatic Animals held, June 24-28, 1985, at the Mote Marine Laboratory in Sarasota, Fla. Bibliography: p. Includes indexes. 1. Aquatic animals—Physiology—Congresses. 2. Senses and Sensation—Congresses. I. Atema, Jelle. II. International Conference on the Sensory Biology - . of Aquatic Animals (1985 : Sarasota, Fla.) QL120.S46 1987 591.92 87-9632 © 1988 by Springer-Verlag New York Inc. x —• All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer-Verlag, 175 Fifth Avenue, New York 10010, U.S.A.), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of Information storage and retrieval, electronic adaptation, Computer Software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of general descriptive names, trade names, trademarks, etc.
    [Show full text]
  • Color and Learn: Sharks of Massachusetts!
    COLOR AND LEARN: SHARKS OF MASSACHUSETTS! This book belongs to: WHAT IS A SHARK? Sharks are fish that have vertebrae (skeletons) made ofcartilage instead of bones. Sharks come in all different shapes, sizes, and colors. Sharks have different kinds of teeth, feeding patterns, swimming styles, and behaviors that help them to survive in all different kinds of aquatic habitats! Can you label the different parts of a shark? second dorsal fin caudal (tail) fin pelvic fin gills anal fin pectoral fin nostril mouth eye Dorsal fin There are around 500 species of sharks in the world. Massachusetts coastal waters provide ideal habitat for several kinds of Atlantic Ocean sharks that visit our waters each season! Massachusetts HOW LONG HAVE SHARKS BEEN ON EARTH? Sharks have been on Earth since before the dinosaurs! Scientists learn about early sharks by studying fossils. Shark fossils can tell us a lot about what food the shark ate, what their habitat looked like, and how they are related to other sharks. The ancient sharks on this page are extinct. Acanthodes (ah-can-tho-deez), or “spiny shark,” was the first fish to have a cartilage skeleton! Cladoselache (clay-do-sel-ah-kee) had a body and tail shaped for swimming fast. It did not have the same kind of skin that we see in modern sharks today. Stethacanthus (stef-ah-can-thus), or “anvil shark”, had a dorsal fin shaped like an ironing board! 450 370 360 200 145 60 6.5 MILLIONS OF YEARS AGO DINOSAURS EVOLVE WHAT ARE “MODERN” SHARKS? “Modern” sharks are species that have body parts (both inside and out!) that can be found on sharks living today.
    [Show full text]
  • I Ecomorphological Change in Lobe-Finned Fishes (Sarcopterygii
    Ecomorphological change in lobe-finned fishes (Sarcopterygii): disparity and rates by Bryan H. Juarez A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science (Ecology and Evolutionary Biology) in the University of Michigan 2015 Master’s Thesis Committee: Assistant Professor Lauren C. Sallan, University of Pennsylvania, Co-Chair Assistant Professor Daniel L. Rabosky, Co-Chair Associate Research Scientist Miriam L. Zelditch i © Bryan H. Juarez 2015 ii ACKNOWLEDGEMENTS I would like to thank the Rabosky Lab, David W. Bapst, Graeme T. Lloyd and Zerina Johanson for helpful discussions on methodology, Lauren C. Sallan, Miriam L. Zelditch and Daniel L. Rabosky for their dedicated guidance on this study and the London Natural History Museum for courteously providing me with access to specimens. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ii LIST OF FIGURES iv LIST OF APPENDICES v ABSTRACT vi SECTION I. Introduction 1 II. Methods 4 III. Results 9 IV. Discussion 16 V. Conclusion 20 VI. Future Directions 21 APPENDICES 23 REFERENCES 62 iv LIST OF TABLES AND FIGURES TABLE/FIGURE II. Cranial PC-reduced data 6 II. Post-cranial PC-reduced data 6 III. PC1 and PC2 Cranial and Post-cranial Morphospaces 11-12 III. Cranial Disparity Through Time 13 III. Post-cranial Disparity Through Time 14 III. Cranial/Post-cranial Disparity Through Time 15 v LIST OF APPENDICES APPENDIX A. Aquatic and Semi-aquatic Lobe-fins 24 B. Species Used In Analysis 34 C. Cranial and Post-Cranial Landmarks 37 D. PC3 and PC4 Cranial and Post-cranial Morphospaces 38 E. PC1 PC2 Cranial Morphospaces 39 1-2.
    [Show full text]
  • Class SARCOPTERYGII Order COELACANTHIFORMES
    click for previous page Coelacanthiformes: Latimeriidae 3969 Class SARCOPTERYGII Order COELACANTHIFORMES LATIMERIIDAE (= Coelacanthidae) Coelacanths by S.L. Jewett A single species occurring in the area. Latimeria menadoensis Pouyaud, Wirjoatmodjo, Rachmatika, Tjakrawidjaja, Hadiaty, and Hadie, 1999 Frequent synonyms / misidentifications: None / Nearly identical in appearance to Latimeria chalumnae Smith, 1939 from the western Indian Ocean. FAO names: En - Sulawesi coelacanth. Diagnostic characters: A large robust fish. Caudal-peduncle depth nearly equal to body depth. Head robust, with large eye, terminal mouth, and large soft gill flap extending posteriorly from opercular bone. Dorsal surface of snout with pits and reticulations comprising part of sensory system. Three large, widely spaced pores on each side of snout, 1 near tip of snout and 2 just anterior to eye, connecting internally to rostral organ. Anterior nostrils form small papillae located at dorsolateral margin of mouth, at anterior end of pseudomaxillary fold (thick, muscularized skin which replaces the maxilla in coelacanths). Ventral side of head with prominent paired gular plates, longitudinally oriented along midline; skull dorsally with pronounced paired bony plates, just above and behind eyes, the posterior margins of which mark exterior manifestation of intracranial joint (or hinge) that divides braincase into anterior and posterior portions (found only in coelacanths). First dorsal fin typical, with 8 stout bony rays. Second dorsal (28 rays), anal (30), paired pectoral (each 30 to 33), and paired pelvic (each 33) fins lobed, i.e. each with a fleshy base, internally supported by an endoskeleton with which terminal fin rays articulate. Caudal fin atypical, consisting of 3 parts: upper and lower portions with numerous rays more or less symmetrically arranged along dorsal and ventral midlines, and a separate smaller terminal portion (sometimes called epicaudal fin) with symmetrically arranged rays.
    [Show full text]
  • The Shark's Electric Sense
    BIOLOGY CREDIT © 2007 SCIENTIFIC AMERICAN, INC. LEMON SHARK chomps down on an unlucky fish. THE SHARK’S SENSE An astonishingly sensitive detector of electric fields helps sharks zero in on prey By R. Douglas Fields menacing fin pierced the surface such as those animal cells produce when in KEY CONCEPTS and sliced toward us. A great blue contact with seawater. But how they use ■ Sharks and related fish can shark—three meters in length— that unique sense had yet to be proved. We sense the extremely weak homed in on the scent of blood like a torpe- were on that boat to find out. electric fields emitted by animals in the surrounding do. As my wife, Melanie, and I watched sev- Until the 1970s, scientists did not even water, an ability few other eral large sharks circle our seven-meter Bos- suspect that sharks could perceive weak organisms possess. ton Whaler, a silver-blue snout suddenly electric fields. Today we know that such elec- ■ This ability is made possible thrust through a square cutout in the boat troreception helps the fish find food and can by unique electrosensory deck. “Look out!” Melanie shouted. We operate even when environmental condi- structures called ampullae both recoiled instinctively, but we were in tions render the five common senses—sight, of Lorenzini, after the 17th- no real danger. The shark flashed a jagged smell, taste, touch, hearing—all but useless. century anatomist who first smile of ivory saw teeth and then slipped It works in turbid water, total darkness and described them. back into the sea.
    [Show full text]