DOCSLIB.ORG

Sharks and Minnows Summer Camp

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sharks and Minnows Summer Camp Sharks and Rays of Florida: a 45-million-year history Victor J. Perez Assistant Curator of Paleontology Calvert Marine Museum Chondrichthyan Tree of Life Modern Cartilaginous Fish • Sharks (>500 species) • Rays (>600 species) • Chimaera (>50 species) Modern Florida Diversity Summary >100 species 11 orders 35 families 54 genera Artist: Sebastien Guyonneau (O’Khaen) Chondrichthyan Tree of Life Project (www.sharksrays.org) Project Origins Driving Question: How has shark and ray diversity changed around the Florida platform? Florida Museum How can we measure biodiversity? 1. Species Richness: The number of species in a specific time and place 2. Species Evenness: The relative abundance of different species in a specific time and place What factors affect fossil diversity? Physical Biological Preservation Collection Effort Ex. Climate Change Ex. Competition Ex. Rock Type Ex. Screenwashing Actual Diversity Trends Biased Diversity Trends Shark Diversity along Calvert Cliffs Visaggi and Godfrey (2010) Florida Surficial Geology Age Range: o Eocene to Present (~48 million years to now) Rock Type: o Sedimentary rocks o Carbonate (Limestone) o Siliciclastic (Sand and Clay) Florida geologic map (Scott et al., 2001). Environmental and Depositional Transition 48 – 34 Ma 34 – 23 Ma 23 – 2.6 Ma Florida was a shallow marine Florida emerges from the sea, Florida connects to the rest of environment, separated from as global temperature drops. the United States. Siliciclastic land by a deep-water channel. Transition in sediment type. deposition ramps up. Adapted from Florida Formations: Shifting Seas and Sediments exhibit, Gillespie Museum, Stetson University. Where do we find fossils in Florida? Beaches! Rivers and streams! Ancient sinkholes! Mines! Construction Sites! FLMNH Specify Database 117,353 specimens 77 taxa (original) 65 taxa (corrected) 10 orders 26 families Oldest Chondrichthyans from FL 41 genera 52 13 Modified from Zachos et al. (2008) Taxonomic Diversity Functional Diversity Based on evolutionary relationships Based on ecological role Compagno (1990) Chondrichthyan Tree of Life Project Catshark Houndshark Bull Shark Tiger Shark Lemon Shark Sharpnose Shark Hammerhead Shark Bonnethead Shark 5 mm Sand Tiger Shark Mako Shark Great White Shark Basking Shark Thresher Shark 1 cm Cookiecutter Shark Cookiecutter Shark Nurse Shark Angel Shark Bullhead Shark Cow Shark 5 mm Bull Ray Cownose Ray Manta Ray Spotted Eagle Ray Whiptail Stingray Wedgefish Sawfish Guitarfish Functional Diversity: Dentition Types Cutting Grasping Crushing Clutching Filter-Feeding 5 mm 5 mm 10 mm Diet Diet Diet Diet Diet Medium to Small to Benthic hard- Benthic, small Microscopic large fleshy medium quick bodied prey soft-bodied prey prey prey Kent (1994) Functional Diversity: Ecomorphotype Ecomorphotype: Habitat Diet Locomotion Anatomy 21 types in the Florida fossil record Compagno (1990) Sampling Effort NALMA / Stage Age Range Time # of # of # of (Ma) Elapsed (Ma) Specimens Sites Formations Rancholabrean 0.012 – 0.25 0.238 779 52 2 Irvingtonian 0.25 – 1.6 1.35 1193 10 3 Blancan 1.6 – 4.75 3.15 1276 31 4 Hemphillian 4.75 – 9.0 4.25 88300 116 4 Clarendonian 9.0 – 12.5 3.5 10200 29 3 Barstovian 12.5 – 15.9 3.4 3438 16 3 Hemingfordian 15.9 – 18.9 3.0 1176 15 4 Arikareean 18.9 – 29.4 10.5 834 11 2 Whitneyan 29.4 – 31.4 2.0 23 1 0 Vicksburgian 31.4 – 33.9 2.5 266 2 2 Jacksonian 33.9 – 37.2 3.3 192 44 1 Claibornian 37.2 – 48.6 11.4 21 2 1 Ken Marks Results: Diversity Trends Taxonomic Diversity Functional Diversity Taxonomic Diversity 100% Discussion Hexanchiformes 80% Squatiniformes Taxonomic Diversity Orectolobiformes 60% Lamniformes Three dominant orders Carcharhiniformes 40% Rhinopristiformes Carcharhiniformes Rajiformes 20% Myliobatiformes Lamniformes Myliobatiformes 0% Shift from lamniform to carcharhiniform dominant fauna across the EOT Carcharhiniforms radiate during the Functional Diversity Miocene 100% Cutting Cutting-Grasping 80% Cutting-Crushing Functional Diversity Cutting-Clutching 60% Grasping Shift from grasping to cutting dominant Grasping-Cutting 40% Dietary preference towards larger prey Crushing Clutching 20% Small, benthic taxa poorly represented Clutching-Crushing Filter-Feeding 0% Eocene Lamniform Diversity of Alabama 10 genera (56% of the fauna) Two morphotypes: (1) Tall, narrow (=grasping) (2) Broadly triangular (=cutting) Cappetta and Case (2016) Lamniform to Carcharhiniform Transition in Maryland Purse State Park (Charles County) Bayfront Park (Calvert County) -Aquia Formation (~60 Ma) -Calvert Formation (~20 Ma) -Mostly grasping-type teeth -Mostly cutting-type teeth Discussion: Sampling Bias Haile Quarry Problems Solutions Preservation Focus efforts on screenwashing • Carbonate vs. Siliciclastic Collection Effort Increase awareness of gaps in the • Focus on the Neogene fossil record (e.g., Paleogene) Research Effort Promote use of myFOSSIL database • Focus on terrestrial vertebrates Temporal Resolution Site-based detailed descriptions • Tied to NALMA and regional lithology Strontium-dating tooth enameloid myFOSSIL Features Contribute to Research Conclusions There was a transition from a lamniform to carcharhiniform- dominant fauna across the EOT There was a long-term trend towards teeth with more efficient cutting adaptations, corresponding with a dietary shift towards larger prey Sampling bias is pervasive in the FLMNH collection, which should dictate future collection and research efforts Sharks! Sink your teeth in! What? New exhibit on sharks When? July 2021 – July 2022 Where? Mezzanine level at CMM.
Load more

Recommended publications
  • Manta Birostris) in CMS Appendix I & II, As Proposed by the Government of Ecuador (I/5)
    SHARK ADVOCATES INTERNATIONAL Support Inclusion of the Giant Manta Ray (Manta birostris) in CMS Appendix I & II, as proposed by the Government of Ecuador (I/5) Overview Mantas, exceptionally large and vulnerable rays found around the world in tropical to temperate waters, are under increasing threat. Critical aggregation areas are at risk while new markets for manta gills drive unsustainable fisheries that may squander substantial economic benefits of manta-based tourism. Some countries have protected manta rays, but additional national safeguards, as well as collaborative regional efforts to study and conserve manta rays, are urgently needed to avoid further depletion of these valuable and iconic animals. The Convention on Migratory Species (CMS) is an ideal vehicle for facilitating conservation of manta rays and their essential habitats. JACKIE REID / NOAA Biological Characteristics and harpoons. Their large size and tendency to move slowly The giant (Manta birostris) and reef (Manta alfredi) manta in predictable aggregations make them easy targets. rays are among the world’s largest fishes. The giant manta ray can grow to more than seven meters across. Manta rays Manta rays are used for human consumption and shark bait, are especially vulnerable to overexploitation due to their very and are increasingly sought for their gill rakers, which are limited reproductive capacity. Female mantas are thought to traded to East Asia for use in Chinese medicine. This relatively mature at 8-10 years of age, produce just one pup after a new market is driving dramatic increases in targeted manta year-long gestation period (with a year or two resting stage), fisheries, particularly in Southeast Asia, India, and Eastern and live at least 30 years.
    [Show full text]
  • Bibliography Database of Living/Fossil Sharks, Rays and Chimaeras (Chondrichthyes: Elasmobranchii, Holocephali) Papers of the Year 2016
    www.shark-references.com Version 13.01.2017 Bibliography database of living/fossil sharks, rays and chimaeras (Chondrichthyes: Elasmobranchii, Holocephali) Papers of the year 2016 published by Jürgen Pollerspöck, Benediktinerring 34, 94569 Stephansposching, Germany and Nicolas Straube, Munich, Germany ISSN: 2195-6499 copyright by the authors 1 please inform us about missing papers: [email protected] www.shark-references.com Version 13.01.2017 Abstract: This paper contains a collection of 803 citations (no conference abstracts) on topics related to extant and extinct Chondrichthyes (sharks, rays, and chimaeras) as well as a list of Chondrichthyan species and hosted parasites newly described in 2016. The list is the result of regular queries in numerous journals, books and online publications. It provides a complete list of publication citations as well as a database report containing rearranged subsets of the list sorted by the keyword statistics, extant and extinct genera and species descriptions from the years 2000 to 2016, list of descriptions of extinct and extant species from 2016, parasitology, reproduction, distribution, diet, conservation, and taxonomy. The paper is intended to be consulted for information. In addition, we provide information on the geographic and depth distribution of newly described species, i.e. the type specimens from the year 1990- 2016 in a hot spot analysis. Please note that the content of this paper has been compiled to the best of our abilities based on current knowledge and practice, however,
    [Show full text]
  • Sharks for the Aquarium and Considerations for Their Selection1 Alexis L
    FA179 Sharks for the Aquarium and Considerations for Their Selection1 Alexis L. Morris, Elisa J. Livengood, and Frank A. Chapman2 Introduction The Lore of the Shark Sharks are magnificent animals and an exciting group Though it has been some 35 years since the shark in Steven of fishes. As a group, sharks, rays, and skates belong to Spielberg’s Jaws bit into its first unsuspecting ocean swim- the biological taxonomic class called Chondrichthyes, or mer and despite the fact that the risk of shark-bite is very cartilaginous fishes (elasmobranchs). The entire supporting small, fear of sharks still makes some people afraid to swim structure of these fish is composed primarily of cartilage in the ocean. (The chance of being struck by lightning is rather than bone. There are some 400 described species of greater than the chance of shark attack.) The most en- sharks, which come in all different sizes from the 40-foot- grained shark image that comes to a person’s mind is a giant long whale shark (Rhincodon typus) to the 2-foot-long conical snout lined with multiple rows of teeth efficient at marble catshark (Atelomycterus macleayi). tearing, chomping, or crushing prey, and those lifeless and staring eyes. The very adaptations that make sharks such Although sharks have been kept in public aquariums successful predators also make some people unnecessarily since the 1860s, advances in marine aquarium systems frightened of them. This is unfortunate, since sharks are technology and increased understanding of shark biology interesting creatures and much more than ill-perceived and husbandry now allow hobbyists to maintain and enjoy mindless eating machines.
    [Show full text]
  • Sharks in Crisis: a Call to Action for the Mediterranean
    REPORT 2019 SHARKS IN CRISIS: A CALL TO ACTION FOR THE MEDITERRANEAN WWF Sharks in the Mediterranean 2019 | 1 fp SECTION 1 ACKNOWLEDGEMENTS Written and edited by WWF Mediterranean Marine Initiative / Evan Jeffries (www.swim2birds.co.uk), based on data contained in: Bartolí, A., Polti, S., Niedermüller, S.K. & García, R. 2018. Sharks in the Mediterranean: A review of the literature on the current state of scientific knowledge, conservation measures and management policies and instruments. Design by Catherine Perry (www.swim2birds.co.uk) Front cover photo: Blue shark (Prionace glauca) © Joost van Uffelen / WWF References and sources are available online at www.wwfmmi.org Published in July 2019 by WWF – World Wide Fund For Nature Any reproduction in full or in part must mention the title and credit the WWF Mediterranean Marine Initiative as the copyright owner. © Text 2019 WWF. All rights reserved. Our thanks go to the following people for their invaluable comments and contributions to this report: Fabrizio Serena, Monica Barone, Adi Barash (M.E.C.O.), Ioannis Giovos (iSea), Pamela Mason (SharkLab Malta), Ali Hood (Sharktrust), Matthieu Lapinksi (AILERONS association), Sandrine Polti, Alex Bartoli, Raul Garcia, Alessandro Buzzi, Giulia Prato, Jose Luis Garcia Varas, Ayse Oruc, Danijel Kanski, Antigoni Foutsi, Théa Jacob, Sofiane Mahjoub, Sarah Fagnani, Heike Zidowitz, Philipp Kanstinger, Andy Cornish and Marco Costantini. Special acknowledgements go to WWF-Spain for funding this report. KEY CONTACTS Giuseppe Di Carlo Director WWF Mediterranean Marine Initiative Email: [email protected] Simone Niedermueller Mediterranean Shark expert Email: [email protected] Stefania Campogianni Communications manager WWF Mediterranean Marine Initiative Email: [email protected] WWF is one of the world’s largest and most respected independent conservation organizations, with more than 5 million supporters and a global network active in over 100 countries.
    [Show full text]
  • Living Systems
    K2 -3 Lesson Plan Living Systems Why not get a hands on experience with your students at Irukandji Shark and Ray Encounters to learn about the oceans ecosystems from Apex Predators to Primary producers. This Lesson plan is designed for students to observe and study the marine environment through interactive educational talks on Elasmobranches Students will be able to Identify and describe the structure and function of living things Interact with the most misunderstood species in our marine systems Shark and Ray and their ecosystems. To observe marine animals and their reliance on all species . Students will look at the impacts on pollutants on marine plants by performing water test on controlled water source for a report. observe the food chain within a marine environment Observe various life cycles of Sharks and Rays. Identify, describe and evaluates the interactions between living things and their effects on the environment Look at Importance of Chondricthyan fishes (Sharks, Rays and Chimeras) to the marine environment and society, through an insightful look into 6 species life history strategies .to identify current conservation efforts of aquariums and marine parks throughout Australia. Irukandji Shark and Ray Encounters K2 -3 Lesson Plan Learning Environment Objectives Observe different elasmobranches Core component is Group Work observe marine animals and relationships Ray Lagoon Food chain within a marine environment Tawny Terrian interactions between living things Fiddler Flats Identify current conservation efforts of aquariums and marine parks throughout Australia. Materials Step 4: Getting wet Ray lagoon 25 minutes This is where students will get a hands on experience feeding, touching and interacting Pencil with elasmobranches and teleost within their Activity sheet environment Ruler and clip board Objectives Observe the different forms of structure Steps from plates to teeth.
    [Show full text]
  • Record of Carcharocles Megalodon in the Eastern
    Estudios Geológicos julio-diciembre 2015, 71(2), e032 ISSN-L: 0367-0449 doi: http://dx.doi.org/10.3989/egeol.41828.342 Record of Carcharocles megalodon in the Eastern Guadalquivir Basin (Upper Miocene, South Spain) Registro de Carcharocles megalodon en el sector oriental de la Cuenca del Guadalquivir (Mioceno superior, Sur de España) M. Reolid, J.M. Molina Departamento de Geología, Universidad de Jaén, Campus Las Lagunillas sn, 23071 Jaén, Spain. Email: [email protected] / [email protected] ABSTRACT Tortonian diatomites of the San Felix Quarry (Porcuna), in the Eastern Guadalquivir Basin, have given isolated marine vertebrate remains that include a large shark tooth (123.96 mm from apex to the baseline of the root). The large size of the crown height (92.2 mm), the triangular shape, the broad serrated crown, the convex lingual face and flat labial face, and the robust, thick angled root determine that this specimen corresponds to Carcharocles megalodon. The symmetry with low slant shows it to be an upper anterior tooth. The total length estimated from the tooth crown height is calculated by means of different methods, and comparison is made with Carcharodon carcharias. The final inferred total length of around 11 m classifies this specimen in the upper size range of the known C. megalodon specimens. The palaeogeography of the Guadalquivir Basin close to the North Betic Strait, which connected the Atlantic Ocean to the Mediterranean Sea, favoured the interaction of the cold nutrient-rich Atlantic waters with warmer Mediterranean waters. The presence of diatomites indicates potential upwelling currents in this context, as well as high productivity favouring the presence of large vertebrates such as mysticetid whales, pinnipeds and small sharks (Isurus).
    [Show full text]
  • Insights Into Insular Isolation of the Bull Shark, Carcharhinus Leucas (Müller and Henle, 1839), in Fijian Waters
    Nova Southeastern University NSUWorks Biology Faculty Articles Department of Biological Sciences 12-14-2020 Insights Into Insular Isolation of the Bull Shark, Carcharhinus leucas (Müller and Henle, 1839), in Fijian Waters Kerstin B J Glaus Sharon A. Appleyard Brian Stockwell Juerg M. Brunnschweiler Mahmood S. Shivji See next page for additional authors Follow this and additional works at: https://nsuworks.nova.edu/cnso_bio_facarticles Part of the Biology Commons Authors Kerstin B J Glaus, Sharon A. Appleyard, Brian Stockwell, Juerg M. Brunnschweiler, Mahmood S. Shivji, Eric Clua, Amandine D. Marie, and Ciro Rico fmars-07-586015 December 14, 2020 Time: 11:37 # 1 ORIGINAL RESEARCH published: 14 December 2020 doi: 10.3389/fmars.2020.586015 Insights Into Insular Isolation of the Bull Shark, Carcharhinus leucas (Müller and Henle, 1839), in Fijian Waters Kerstin B. J. Glaus1*, Sharon A. Appleyard2†, Brian Stockwell1†, Juerg M. Brunnschweiler3, Mahmood Shivji4, Eric Clua5, Amandine D. Marie1,6 and Ciro Rico1,7 1 School of Marine Studies, Faculty of Science, Technology and Environment, The University of the South Pacific, Suva, Fiji, 2 CSIRO National Research Collections Australia, Australian National Fish Collection, Hobart, TAS, Australia, 3 Independent Researcher, Zurich, Switzerland, 4 Save Our Seas Foundation Shark Research Center, Nova Southeastern University, Fort Lauderdale, FL, United States, 5 PSL Research University, Labex CORAIL, CRIOBE USR 3278 CNRS-EPHE-UPVD, Université de Perpignan, Perpignan, France, 6 ESE, Ecology and Ecosystems Health, Agrocampus Ouest, INRAE, Rennes, France, 7 Instituto de Ciencias Marinas de Andalucía (ICMAN), Consejo Superior de Investigaciones Científicas, Puerto Real, Edited by: Spain Lorenzo Zane, University of Padua, Italy Reviewed by: The bull shark (Carcharhinus leucas) is a large, mobile, circumglobally distributed Ka Yan Ma, high trophic level predator that inhabits a variety of remote islands and continental Sun Yat-sen University, China Simo Njabulo Maduna, coastal habitats, including freshwater environments.
    [Show full text]
  • Western Spotted Catshark, Asymbolus Occiduus
    Published Date: 1 March 2019 Western Spotted Catshark, Asymbolus occiduus Report Card Sustainable assessment IUCN Red List IUCN Red List Australian Endemic to Australia Global Least Concern Assessment Assessment Assessors Simpfendorfer, C. & Heupel, M.R. Report Card Remarks Little known shark with limited fishing across its range Summary The Western Spotted Catshark is a small, little known temperate catshark. It is endemic to southern Australia and has a reasonably large geographic and depth range. The species is unlikely to Source: CSIRO National Fish Collection. License: CC BY Attribution be negatively affected by commercial fisheries because there is limited fishing throughout its range. Therefore, it is assessed as Least Concern (IUCN) and Sustainable (SAFS). Distribution The Western Spotted Catshark is distributed along the southern and western coasts of Australia from Fowlers Bay (South Australia) to Perth (Western Australia) (Last and Stevens 2009). Stock structure and status There is currently no information on population size, structure, or trend for the species. Fisheries The Western Spotted Catshark is caught incidentally and very infrequently in the Southern and Eastern Scalefish and Shark Fishery (SESSF). An estimated 69 kg of the species were caught and discarded annually from 2000 to 2006 (Walker and Gason 2007). Habitat and biology The Western Spotted Catshark is found at depths of 98 to 400 m and is most abundant on the outer continental shelf and common off the Western Australian coast. The biology of the species is almost entirely unknown. Adults and juveniles differ significantly in their colour patterns and the association between the two forms was only made recently (Last and Stevens 2009).
    [Show full text]
  • Papers in Press
    Papers in Press “Papers in Press” includes peer-reviewed, accepted manuscripts of research articles, reviews, and short notes to be published in Paleontological Research. They have not yet been copy edited and/or formatted in the publication style of Paleontological Research. As soon as they are printed, they will be removed from this website. Please note they can be cited using the year of online publication and the DOI, as follows: Humblet, M. and Iryu, Y. 2014: Pleistocene coral assemblages on Irabu-jima, South Ryukyu Islands, Japan. Paleontological Research, doi: 10.2517/2014PR020. doi:10.2517/2018PR013 Features and paleoecological significance of the shark fauna from the Upper Cretaceous Hinoshima Formation, Himenoura Group, Southwest Japan Accepted Naoshi Kitamura 4-8-7 Motoyama, Chuo-ku Kumamoto, Kumamoto 860-0821, Japan (e-mail: [email protected]) Abstract. The shark fauna of the Upper Cretaceous Hinoshima Formation (Santonian: 86.3–83.6 Ma) of the manuscriptHimenoura Group (Kamiamakusa, Kumamoto Prefecture, Kyushu, Japan) was investigated based on fossil shark teeth found at five localities: Himedo Park, Kugushima, Wadanohana, Higashiura, and Kotorigoe. A detailed geological survey and taxonomic analysis was undertaken, and the habitat, depositional environment, and associated mollusks of each locality were considered in the context of previous studies. Twenty-one species, 15 genera, 11 families, and 6 orders of fossil sharks are recognized from the localities. This assemblage is more diverse than has previously been reported for Japan, and Lamniformes and Hexanchiformes were abundant. Three categories of shark fauna are recognized: a coastal region (Himedo Park; probably a breeding site), the coast to the open sea (Kugushima and Wadanohana), and bottom-dwelling or near-seafloor fauna (Kugushima, Wadanohana, Higashiura, and Kotorigoe).
    [Show full text]
  • First Evidence of Multiple Paternity in the Bull Shark (Carcharhinus Leucas) Agathe Pirog, Sébastien Jaquemet, Marc Soria, Hélène Magalon
    First evidence of multiple paternity in the bull shark (Carcharhinus leucas) Agathe Pirog, Sébastien Jaquemet, Marc Soria, Hélène Magalon To cite this version: Agathe Pirog, Sébastien Jaquemet, Marc Soria, Hélène Magalon. First evidence of multiple paternity in the bull shark (Carcharhinus leucas). Marine and Freshwater Research, CSIRO Publishing, 2015, 10.1071/mf15255. hal-01253775 HAL Id: hal-01253775 https://hal.archives-ouvertes.fr/hal-01253775 Submitted on 4 May 2016 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. First evidence of multiple paternity in the bull shark (Carcharhinus leucas) Agathe PirogA, Se´bastien JaquemetA,B, Marc SoriaC and He´le`ne MagalonA,B,D AUniversite´ de La Re´union, UMR 9220 ENTROPIE (Universite´ de La Re´union/IRD/CNRS), 15 Avenue Rene´ Cassin, CS 92003, F-97744 Saint Denis Cedex 09, La Re´union, France. BLaboratory of Excellence CORAIL, 58, Avenue Paul Alduy, F-66860 Perpignan Cedex, France. CIRD Re´union, UMR 248 MARBEC, CS 41095 2 rue Joseph Wetzell, F-97492 Sainte-Clotilde, La Re´union, France. DCorresponding author. Email: [email protected] Abstract. The present study assessed the occurrence of multiple paternity in four litters of bull shark Carcharhinus leucas (n ¼ 5, 8, 9 and 11 embryos) sampled at Reunion Island in the Western Indian Ocean.
    [Show full text]
  • An Introduction to the Classification of Elasmobranchs
    An introduction to the classification of elasmobranchs 17 Rekha J. Nair and P.U Zacharia Central Marine Fisheries Research Institute, Kochi-682 018 Introduction eyed, stomachless, deep-sea creatures that possess an upper jaw which is fused to its cranium (unlike in sharks). The term Elasmobranchs or chondrichthyans refers to the The great majority of the commercially important species of group of marine organisms with a skeleton made of cartilage. chondrichthyans are elasmobranchs. The latter are named They include sharks, skates, rays and chimaeras. These for their plated gills which communicate to the exterior by organisms are characterised by and differ from their sister 5–7 openings. In total, there are about 869+ extant species group of bony fishes in the characteristics like cartilaginous of elasmobranchs, with about 400+ of those being sharks skeleton, absence of swim bladders and presence of five and the rest skates and rays. Taxonomy is also perhaps to seven pairs of naked gill slits that are not covered by an infamously known for its constant, yet essential, revisions operculum. The chondrichthyans which are placed in Class of the relationships and identity of different organisms. Elasmobranchii are grouped into two main subdivisions Classification of elasmobranchs certainly does not evade this Holocephalii (Chimaeras or ratfishes and elephant fishes) process, and species are sometimes lumped in with other with three families and approximately 37 species inhabiting species, or renamed, or assigned to different families and deep cool waters; and the Elasmobranchii, which is a large, other taxonomic groupings. It is certain, however, that such diverse group (sharks, skates and rays) with representatives revisions will clarify our view of the taxonomy and phylogeny in all types of environments, from fresh waters to the bottom (evolutionary relationships) of elasmobranchs, leading to a of marine trenches and from polar regions to warm tropical better understanding of how these creatures evolved.
    [Show full text]
  • A Systematic Revision of the South American Freshwater Stingrays (Chondrichthyes: Potamotrygonidae) (Batoidei, Myliobatiformes, Phylogeny, Biogeography)
    W&M ScholarWorks Dissertations, Theses, and Masters Projects Theses, Dissertations, & Master Projects 1985 A systematic revision of the South American freshwater stingrays (chondrichthyes: potamotrygonidae) (batoidei, myliobatiformes, phylogeny, biogeography) Ricardo de Souza Rosa College of William and Mary - Virginia Institute of Marine Science Follow this and additional works at: https://scholarworks.wm.edu/etd Part of the Fresh Water Studies Commons, Oceanography Commons, and the Zoology Commons Recommended Citation Rosa, Ricardo de Souza, "A systematic revision of the South American freshwater stingrays (chondrichthyes: potamotrygonidae) (batoidei, myliobatiformes, phylogeny, biogeography)" (1985). Dissertations, Theses, and Masters Projects. Paper 1539616831. https://dx.doi.org/doi:10.25773/v5-6ts0-6v68 This Dissertation is brought to you for free and open access by the Theses, Dissertations, & Master Projects at W&M ScholarWorks. It has been accepted for inclusion in Dissertations, Theses, and Masters Projects by an authorized administrator of W&M ScholarWorks. For more information, please contact [email protected]. INFORMATION TO USERS This reproduction was made from a copy of a document sent to us for microfilming. While the most advanced technology has been used to photograph and reproduce this document, the quality of the reproduction is heavily dependent upon the quality of the material submitted. The following explanation of techniques is provided to help clarify markings or notations which may appear on this reproduction. 1.The sign or “target” for pages apparently lacking from the document photographed is “Missing Pagefs)”. If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure complete continuity.
    [Show full text]