DOCSLIB.ORG

BOA2.1 Caecilian Biology and Natural History.Key

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
BOA2.1 Caecilian Biology and Natural History.Key The Biology of Amphibians @ Agnes Scott College Mark Mandica Executive Director The Amphibian Foundation [email protected] 678 379 TOAD (8623) 2.1: Introduction to Caecilians Microcaecilia dermatophaga Synapomorphies of Lissamphibia There are more than 20 synapomorphies (shared characters) uniting the group Lissamphibia Synapomorphies of Lissamphibia Integumen is Glandular Synapomorphies of Lissamphibia Glandular Skin, with 2 main types of glands. Mucous Glands Aid in cutaneous respiration, reproduction, thermoregulation and defense. Granular Glands Secrete toxic and/or noxious compounds and aid in defense Synapomorphies of Lissamphibia Pedicellate Teeth crown (dentine, with enamel covering) gum line suture (fibrous connective tissue, where tooth can break off) basal element (dentine) Synapomorphies of Lissamphibia Sacral Vertebrae Sacral Vertebrae Connects pelvic girdle to The spine. Amphibians have no more than one sacral vertebrae (caecilians have none) Synapomorphies of Lissamphibia Amphicoelus Vertebrae Synapomorphies of Lissamphibia Opercular apparatus Unique to amphibians and Operculum part of the sound conducting mechanism Synapomorphies of Lissamphibia Fat Bodies Surrounding Gonads Fat Bodies Insulate gonads Evolution of Amphibians † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Anura (including Apoda Urodela Prosalirus †) Salientia Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Amphibian Reign Time Period Devonian Carboniferus Permian Triassic Jurassic Cretaceous Millions of Years Ago (420 MYA) (350 MYA) (300 MYA) (250 MYA) (200 MYA) (150-65 MYA) Present Day resembles Plate Tectonics Gondwana + Laurussia Pangea Pangea Pangea begins to break Pangea breaks present day The Biology of Amphibians amphibbio.amphibianfoundation.org CLassification of Order: Gymnophiona † Eocaecilia Rhinatrematidae Ichthyophiidae Scolecomorphidae Chikilidae Herpelidae Caeciliidae Typhlonectidae Indotyphiidae Dermophiidae Siphonopidae † † † † Actinopterygian Coelacanth, Tetrapodomorpha †Amniota *Gerobatrachus (Ray-fin Fishes) Lungfish (stem-tetrapods) (Reptiles, Mammals)Lepospondyls † (’frogomander’) Eocaecilia GymnophionaKaraurus Caudata Triadobatrachus Gymnophiona Anura (including Apoda Urodela Prosalirus †) Salientia Apoda Batrachia Lissamphibia *Gerobatrachus may be the sister taxon Temnospondyls † to Batrachia Tetrapods Osteichthyes Sarcopterygian (Bony Fishes) (Lobe-fin Fishes) Lissamphibia The Biology of Amphibians amphibbio.amphibianfoundation.org Order: Gymnophiona | Family: Ichthyophiidae cloaca tail tentacular organ annuli Ichthyophis kohtaoensis Order: Gymnophiona The ‘naked snakes’ Apoda (no feet) includes all amphibians more closely related to caecilians than to frogs or salamanders, including Eocaecilia micropodia † (which had tentacular fossa and an os basale), as well as Rubricacaecilia monbaroni † and Chinlestegophis † Fossorial (though several species are aquatic) Pan-tropical distribution (excluding Madagascar) Order: Gymnophiona Order: Gymnophiona Integumen Dermal Scales - Present in some species of caecilian, but no other Lissamphibia Dermal Scales - Found in pouches below Annular Groove Poison - Not all caecilians have been tested, but based on the samples of Siphonops and Typhlonectes, at least most caecilians are toxic to predators* *see Jared, 2018 - in the ‘additional readings’ folder for a great description of the use of toxin in Siphonops Order: Gymnophiona Coral Snake vs Caecilian Order: Gymnophiona Integumen Lateral Line System - Caecilians posses a lateral line system - a sensory system located in the epidermis of the head and body. They consist of two types of receptors. A. Ampullary Organs - Electroreceptors (the solid structures in the figure on right) B. Neuromasts - Mechanoreceptors (the open structures in the figure on right) Ichthyophis sp. Order: Gymnophiona Anatomy Annular Grooves - Primary, Secondary and Tertiary annuli correspond with vertebrae Order: Gymnophiona | Family: Siphonopidae Primary annuli Siphonops sp. Order: Gymnophiona | Family: Dermophiidae Tertiary annuli Secondary annuli Primary annuli Gymnopis multiplicata Order: Gymnophiona Anatomy Caecilians lack limbs and girdles Order: Gymnophiona Anatomy Caecilians lack limbs and girdles Order: Gymnophiona Anatomy Tail - Cloaca at end of the body. Caecilians either have no tail (synapomorphy) or short tail (pleisiomorphy) Order: Gymnophiona Anatomy Tail - Cloaca at end of the body. Caecilians either have no tail (synapomorphy) or short tail (pleisiomorphy) Order: Gymnophiona Small vestigial eyes Can only detect light and dark Are covered with skin or bone The Caecilian Skull Order: Gymnophiona The Caecilian Skull High ossification and reduction in number of bones (fused) to increase strength of skull, which is basically used as a battering ram through the dirt. Caecilian skulls are adapted for burrowing. Order: Gymnophiona The Caecilian Skull Two main skull conditions in caecilians, the stegokrotaphic condition in which the bones of the skull are completely fused, and the zygokrotaphic condition, which allows for kinetic movement, in a ‘zone of weakness’ between the parietal and squamosal bones in the temporal region. Order: Gymnophiona The Caecilian Skull The Os basale is unique to caecilians, and is a shared trait by extant caecilians (Gymnophiona) as well as all of Apoda, including Eocaecilia †. It is the formation of the fused parasphenoid, basioccipitals, exoccipitals, and otic capsules. Caecilians also posses two rows of maxillary pedicellate teeth on the upper jaw. This feature, with the fused condition of the skull makes them easily recognizable. Order: Gymnophiona The Caecilian Skull The caecilian skull is adapted to exert maximum force on the soil in which it burrows (with its face) Caecilians also have tremendous bite force which is delivered through a series of muscles using the retroarticular process of the jaw as a lever to increase force without adding lateral girth (which would impede burrowing) Order: Gymnophiona The Caecilian Skull Os basale tentacular fossa maxillary retroarticular process articulation pseudo dentary The Caecilian Skull Jaw adduction musculature Longis capitus Interhyoideus posterior major temporalis Temporalis: adducts the upper and lower jaw; Longis capitus connects the vertebrae with the base of the skull, when contracted, the skull is rotated down onto the jaw; Interhyoideus posterior major originates in the fascia of the ventral and lateral body wall and inserts on the retroarticular process. When contracted it pulls on the process like a lever The Caecilian Skull Jaw adduction musculature Temporalis: adducts the upper and lower jaw; Longis capitus connects the vertebrae with the base of the skull, when contracted, the skull is rotated down onto the jaw; Interhyoideus posterior major originates in the fascia of the ventral and lateral body wall and inserts on the retroarticular process. When contracted it pulls on the process like a lever The Caecilian Skull Jaw Mental Symphisis V VV Caecilian teeth fit like this The mental symphisis firmly fused at the joining of Articulation Retroarticular the left and right lower jaw bones Process The Caecilian Skull Tentacular organ The tentacular organ. The only example of a tentacle in all of vertebrates. This organ is a chemosensory receptor. The Caecilian Skull Tentacular organ tentacular fossa The Caecilian Skull Terminal mouth Sub-terminal mouth (pleisiomorphic) (apomorphic) Order: Gymnophiona Reproduction Order: Gymnophiona Internal fertilization (Quite a novelty in the amphibian world) Reproduction is internal via the male copulatory organ — the phallodeum phallodeum Internal fertilization in caecilians Order: Gymnophiona Internal fertilization Order: Gymnophiona Caecilian Reproduction Viviparous bringing forth live young that have developed inside the body of the parent. Oviparous producing young by means of eggs that are hatched after they have been laid by the parent. Order: Gymnophiona Caecilian Embryonic Development Stages in the development of the caecilian Ichthyophis glutinosus. A. Neurulation. B. Early organogenesis. C. Late development. Branchial arches are designated by roman numerals. Caecilian Fetal Development Oviparous caecilians can lay their eggs in or near water, which hatch into free- swimming larvae, as is common with most amphibians. These caecilian larvae have large, leaf-like gills which are Oviparous Caecilians resorbed at metamorphosis. Oviparous Oviparous caecilians can also lay their eggs terrestrially, which are direct developing, skipping the free- swimming larval stage and hatch into miniature versions of the adult form. Chikila sp. Viviparous Typhlonectes natans Herpele squalostoma Viviparous caecilians can be aquatic or terrestrial. Viviparity is the most common condition and is considered apomorphic among the more derived caecilians. Typhlonectes natans Viviparous Although most caecilians are viviparous, only certain groups exhibit a novel form of nutrient provisioning for their offspring called maternal dermophagy. Schistometopum thomense Viviparous With maternal dermophagy, the mother produces a nutritious outer layer of skin for her young to feed on by scraping with their ‘paint scraper’ like teeth. This provides nourishment which allows the young caecilians to grow and mature rapidly The mother can replace this skin layer in a couple of days. Dermophagy occurs externally, with the outer layer of skin (as pictured) or internally with offspring feeding on the uterine lining. Viviparous Fetal Teeth Parental Care.
Load more

Recommended publications
  • Amphibians in Zootaxa: 20 Years Documenting the Global Diversity of Frogs, Salamanders, and Caecilians
    Zootaxa 4979 (1): 057–069 ISSN 1175-5326 (print edition) https://www.mapress.com/j/zt/ Review ZOOTAXA Copyright © 2021 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4979.1.9 http://zoobank.org/urn:lsid:zoobank.org:pub:972DCE44-4345-42E8-A3BC-9B8FD7F61E88 Amphibians in Zootaxa: 20 years documenting the global diversity of frogs, salamanders, and caecilians MAURICIO RIVERA-CORREA1*+, DIEGO BALDO2*+, FLORENCIA VERA CANDIOTI3, VICTOR GOYANNES DILL ORRICO4, DAVID C. BLACKBURN5, SANTIAGO CASTROVIEJO-FISHER6, KIN ONN CHAN7, PRISCILLA GAMBALE8, DAVID J. GOWER9, EVAN S.H. QUAH10, JODI J. L. ROWLEY11, EVAN TWOMEY12 & MIGUEL VENCES13 1Grupo Herpetológico de Antioquia - GHA and Semillero de Investigación en Biodiversidad - BIO, Universidad de Antioquia, Antioquia, Colombia [email protected]; https://orcid.org/0000-0001-5033-5480 2Laboratorio de Genética Evolutiva, Instituto de Biología Subtropical (CONICET-UNaM), Facultad de Ciencias Exactas Químicas y Naturales, Universidad Nacional de Misiones, Posadas, Misiones, Argentina [email protected]; https://orcid.org/0000-0003-2382-0872 3Unidad Ejecutora Lillo, Consejo Nacional de Investigaciones Científicas y Técnicas - Fundación Miguel Lillo, 4000 San Miguel de Tucumán, Argentina [email protected]; http://orcid.org/0000-0002-6133-9951 4Laboratório de Herpetologia Tropical, Universidade Estadual de Santa Cruz, Departamento de Ciências Biológicas, Rodovia Jorge Amado Km 16 45662-900 Ilhéus, Bahia, Brasil [email protected]; https://orcid.org/0000-0002-4560-4006 5Florida Museum of Natural History, University of Florida, 1659 Museum Road, Gainesville, Florida, 32611, USA [email protected]; https://orcid.org/0000-0002-1810-9886 6Laboratório de Sistemática de Vertebrados, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Av.
    [Show full text]
  • Chec List a Checklist of the Amphibians and Reptiles of San
    Check List 10(4): 870–877, 2014 © 2014 Check List and Authors Chec List ISSN 1809-127X (available at www.checklist.org.br) Journal of species lists and distribution PECIES S OF A checklist * of the amphibians and reptiles of San Isidro de ISTS L Dota, Reserva Forestal Los Santos, Costa Rica Erick Arias and Federico Bolaños [email protected] Universidad de Costa Rica, Escuela de Biología, Museo de Zoología. San Pedro, 11501-2060, San José, Costa Rica. * Corresponding author. E-mail: Abstract: We present an inventory of amphibians and reptiles of San Isidro de Dota, northwest of the Cordillera de Talamanca in the Central Pacific of Costa Rica.Leptodactylus The study was insularum conduced from January to August 2012 in premontane wet Coloptychonforest from 689 rhombifer m to 800 m elevation. We found a total of 56 species, including 30 species of amphibians and 26 of reptiles. It results striking the presence of the frog , uncommon above 400 m elevation, and the lizard , a very uncommon species. DOI: 10.15560/10.4.870 Introduction datum, from 689 m to 800 N, 83°58′32.41″ W, WGS84et al. Lower Central America represents one of the regions m elevation). The region is dominated by premontane with the highest numberet al of amphibianset describedal. in the wet forest (Bolaños 1999) with several sites used Neotropics in relation to the area it represent (Savage for agriculture and pastures. The region presents the 2002; Boza-Oviedo . 2012; Hertz 2012). Much climate of the pacific slope of the Cordillera de Talamanca, of this richness of species iset associated al.
    [Show full text]
  • AMS112 1978-1979 Lowres Web
    --~--------~--------------------------------------------~~~~----------~-------------- - ~------------------------------ COVER: Paul Webber, technical officer in the Herpetology department searchers for reptiles and amphibians on a field trip for the Colo River Survey. Photo: John Fields!The Australian Museum. REPORT of THE AUSTRALIAN MUSEUM TRUST for the YEAR ENDED 30 JUNE , 1979 ST GOVERNMENT PRINTER, NEW SOUTH WALES-1980 D. WE ' G 70708K-1 CONTENTS Page Page Acknowledgements 4 Department of Palaeontology 36 The Australian Museum Trust 5 Department of Terrestrial Invertebrate Ecology 38 Lizard Island Research Station 5 Department of Vertebrate Ecology 38 Research Associates 6 Camden Haven Wildlife Refuge Study 39 Associates 6 Functional Anatomy Unit.. 40 National Photographic Index of Australian Director's Research Laboratory 40 Wildlife . 7 Materials Conservation Section 41 The Australian Museum Society 7 Education Section .. 47 Letter to the Premier 9 Exhibitions Department 52 Library 54 SCIENTIFIC DEPARTMENTS Photographic and Visual Aid Section 54 Department of Anthropology 13 PublicityJ Pu bl ications 55 Department of Arachnology 18 National Photographic Index of Australian Colo River Survey .. 19 Wildlife . 57 Lizard Island Research Station 59 Department of Entomology 20 The Australian Museum Society 61 Department of Herpetology 23 Appendix 1- Staff .. 62 Department of Ichthyology 24 Appendix 2-Donations 65 Department of Malacology 25 Appendix 3-Acknowledgements of Co- Department of Mammalogy 27 operation. 67 Department of Marine
    [Show full text]
  • The Care and Captive Breeding of the Caecilian Typhlonectes Natans
    HUSBANDRY AND PROPAGATION The care and captive breeding of the caecilian Typhlonectes natans RICHARD PARKINSON Ecology UK, 317 Ormskirk Road, Upholland, Skelmersdale, Lancashire, UK E-mail: [email protected] riAECILIANS (Apoda) are the often overlooked Many caecilians have no larval stage and, while third order of amphibians and are not thought some lay eggs, many including Typhlonectes natans to be closely-related to either Anurans or Urodelans. give birth to live young after a long pregnancy. Despite the existence of over 160 species occurring Unlike any other amphibian (or reptile) this is a true throughout the tropics (excluding Australasia and pregnancy in which the membranous gills of the Madagascar), relatively little is known about them. embryo functions like the placenta in mammals, so The earliest known fossil caecilian is Eocaecilia that the mother can supply the embryo with oxygen. micropodia, which is dated to the early Jurassic The embryo consumes nutrients secreted by the Period approximately 240 million years ago. uterine walls using specialized teeth for the Eocaecilia micropodia still possessed small but purpose. well developed legs like modem amphiumas and sirens. The worm-like appearance and generally Captive Care subterranean habits of caecilians has often led to In March 1995 I acquired ten specimens of the their dismissal as primitive and uninteresting. This aquatic caecilian Typhlonectes natans (identified by view-point is erroneous. Far from being primitive, cloacae denticulation after Wilkinson, 1996) which caecilians are highly adapted to their lifestyle. had been imported from Guyana. I immediately lost 7),phlonectes natans are minimalist organisms two as a result of an ill-fitting aquarium lid.
    [Show full text]
  • Bioseries12-Amphibians-Taita-English
    0c m 12 Symbol key 3456 habitat pond puddle river stream 78 underground day / night day 9101112131415161718 night altitude high low vegetation types shamba forest plantation prelim pages ENGLISH.indd ii 2009/10/22 02:03:47 PM SANBI Biodiversity Series Amphibians of the Taita Hills by G.J. Measey, P.K. Malonza and V. Muchai 2009 prelim pages ENGLISH.indd Sec1:i 2009/10/27 07:51:49 AM SANBI Biodiversity Series The South African National Biodiversity Institute (SANBI) was established on 1 September 2004 through the signing into force of the National Environmental Management: Biodiversity Act (NEMBA) No. 10 of 2004 by President Thabo Mbeki. The Act expands the mandate of the former National Botanical Institute to include responsibilities relating to the full diversity of South Africa’s fauna and ora, and builds on the internationally respected programmes in conservation, research, education and visitor services developed by the National Botanical Institute and its predecessors over the past century. The vision of SANBI: Biodiversity richness for all South Africans. SANBI’s mission is to champion the exploration, conservation, sustainable use, appreciation and enjoyment of South Africa’s exceptionally rich biodiversity for all people. SANBI Biodiversity Series publishes occasional reports on projects, technologies, workshops, symposia and other activities initiated by or executed in partnership with SANBI. Technical editor: Gerrit Germishuizen Design & layout: Elizma Fouché Cover design: Elizma Fouché How to cite this publication MEASEY, G.J., MALONZA, P.K. & MUCHAI, V. 2009. Amphibians of the Taita Hills / Am bia wa milima ya Taita. SANBI Biodiversity Series 12. South African National Biodiversity Institute, Pretoria.
    [Show full text]
  • Amphibian Alliance for Zero Extinction Sites in Chiapas and Oaxaca
    Amphibian Alliance for Zero Extinction Sites in Chiapas and Oaxaca John F. Lamoreux, Meghan W. McKnight, and Rodolfo Cabrera Hernandez Occasional Paper of the IUCN Species Survival Commission No. 53 Amphibian Alliance for Zero Extinction Sites in Chiapas and Oaxaca John F. Lamoreux, Meghan W. McKnight, and Rodolfo Cabrera Hernandez Occasional Paper of the IUCN Species Survival Commission No. 53 The designation of geographical entities in this book, and the presentation of the material, do not imply the expression of any opinion whatsoever on the part of IUCN concerning the legal status of any country, territory, or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The views expressed in this publication do not necessarily reflect those of IUCN or other participating organizations. Published by: IUCN, Gland, Switzerland Copyright: © 2015 International Union for Conservation of Nature and Natural Resources Reproduction of this publication for educational or other non-commercial purposes is authorized without prior written permission from the copyright holder provided the source is fully acknowledged. Reproduction of this publication for resale or other commercial purposes is prohibited without prior written permission of the copyright holder. Citation: Lamoreux, J. F., McKnight, M. W., and R. Cabrera Hernandez (2015). Amphibian Alliance for Zero Extinction Sites in Chiapas and Oaxaca. Gland, Switzerland: IUCN. xxiv + 320pp. ISBN: 978-2-8317-1717-3 DOI: 10.2305/IUCN.CH.2015.SSC-OP.53.en Cover photographs: Totontepec landscape; new Plectrohyla species, Ixalotriton niger, Concepción Pápalo, Thorius minutissimus, Craugastor pozo (panels, left to right) Back cover photograph: Collecting in Chamula, Chiapas Photo credits: The cover photographs were taken by the authors under grant agreements with the two main project funders: NGS and CEPF.
    [Show full text]
  • Cape Range National Park
    Cape Range National Park Management Plan No 65 2010 R N V E M E O N G T E O H F T W A E I S L T A E R R N A U S T CAPE RANGE NATIONAL PARK Management Plan 2010 Department of Environment and Conservation Conservation Commission of Western Australia VISION By 2020, the park and the Ningaloo Marine Park will be formally recognised amongst the world’s most valuable conservation and nature based tourism icons. The conservation values of the park will be in better condition than at present. This will have been achieved by reducing stress on ecosystems to promote their natural resilience, and facilitating sustainable visitor use. In particular, those values that are not found or are uncommon elsewhere will have been conserved, and their special conservation significance will be recognised by the local community and visitors. The park will continue to support a wide range of nature-based recreational activities with a focus on preserving the remote and natural character of the region. Visitors will continue to enjoy the park, either as day visitors from Exmouth or by camping in the park itself at one of the high quality camping areas. The local community will identify with the park and the adjacent Ningaloo Marine Park, and recognise that its values are of international significance. An increasing number of community members will support and want to be involved in its ongoing management. The Indigenous heritage of the park will be preserved by the ongoing involvement of the traditional custodians, who will have a critical and active role in jointly managing the cultural and conservation values of the park.
    [Show full text]
  • Tetrapod Biostratigraphy and Biochronology of the Triassic–Jurassic Transition on the Southern Colorado Plateau, USA
    Palaeogeography, Palaeoclimatology, Palaeoecology 244 (2007) 242–256 www.elsevier.com/locate/palaeo Tetrapod biostratigraphy and biochronology of the Triassic–Jurassic transition on the southern Colorado Plateau, USA Spencer G. Lucas a,⁎, Lawrence H. Tanner b a New Mexico Museum of Natural History, 1801 Mountain Rd. N.W., Albuquerque, NM 87104-1375, USA b Department of Biology, Le Moyne College, 1419 Salt Springs Road, Syracuse, NY 13214, USA Received 15 March 2006; accepted 20 June 2006 Abstract Nonmarine fluvial, eolian and lacustrine strata of the Chinle and Glen Canyon groups on the southern Colorado Plateau preserve tetrapod body fossils and footprints that are one of the world's most extensive tetrapod fossil records across the Triassic– Jurassic boundary. We organize these tetrapod fossils into five, time-successive biostratigraphic assemblages (in ascending order, Owl Rock, Rock Point, Dinosaur Canyon, Whitmore Point and Kayenta) that we assign to the (ascending order) Revueltian, Apachean, Wassonian and Dawan land-vertebrate faunachrons (LVF). In doing so, we redefine the Wassonian and the Dawan LVFs. The Apachean–Wassonian boundary approximates the Triassic–Jurassic boundary. This tetrapod biostratigraphy and biochronology of the Triassic–Jurassic transition on the southern Colorado Plateau confirms that crurotarsan extinction closely corresponds to the end of the Triassic, and that a dramatic increase in dinosaur diversity, abundance and body size preceded the end of the Triassic. © 2006 Elsevier B.V. All rights reserved. Keywords: Triassic–Jurassic boundary; Colorado Plateau; Chinle Group; Glen Canyon Group; Tetrapod 1. Introduction 190 Ma. On the southern Colorado Plateau, the Triassic– Jurassic transition was a time of significant changes in the The Four Corners (common boundary of Utah, composition of the terrestrial vertebrate (tetrapod) fauna.
    [Show full text]
  • Constraints on the Timescale of Animal Evolutionary History
    Palaeontologia Electronica palaeo-electronica.org Constraints on the timescale of animal evolutionary history Michael J. Benton, Philip C.J. Donoghue, Robert J. Asher, Matt Friedman, Thomas J. Near, and Jakob Vinther ABSTRACT Dating the tree of life is a core endeavor in evolutionary biology. Rates of evolution are fundamental to nearly every evolutionary model and process. Rates need dates. There is much debate on the most appropriate and reasonable ways in which to date the tree of life, and recent work has highlighted some confusions and complexities that can be avoided. Whether phylogenetic trees are dated after they have been estab- lished, or as part of the process of tree finding, practitioners need to know which cali- brations to use. We emphasize the importance of identifying crown (not stem) fossils, levels of confidence in their attribution to the crown, current chronostratigraphic preci- sion, the primacy of the host geological formation and asymmetric confidence intervals. Here we present calibrations for 88 key nodes across the phylogeny of animals, rang- ing from the root of Metazoa to the last common ancestor of Homo sapiens. Close attention to detail is constantly required: for example, the classic bird-mammal date (base of crown Amniota) has often been given as 310-315 Ma; the 2014 international time scale indicates a minimum age of 318 Ma. Michael J. Benton. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. [email protected] Philip C.J. Donoghue. School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, U.K. [email protected] Robert J.
    [Show full text]
  • Morphological Evolution and Modularity of the Caecilian Skull Carla Bardua1,2* , Mark Wilkinson1, David J
    Bardua et al. BMC Evolutionary Biology (2019) 19:30 https://doi.org/10.1186/s12862-018-1342-7 RESEARCH ARTICLE Open Access Morphological evolution and modularity of the caecilian skull Carla Bardua1,2* , Mark Wilkinson1, David J. Gower1, Emma Sherratt3 and Anjali Goswami1,2 Abstract Background: Caecilians (Gymnophiona) are the least speciose extant lissamphibian order, yet living forms capture approximately 250 million years of evolution since their earliest divergences. This long history is reflected in the broad range of skull morphologies exhibited by this largely fossorial, but developmentally diverse, clade. However, this diversity of form makes quantification of caecilian cranial morphology challenging, with highly variable presence or absence of many structures. Consequently, few studies have examined morphological evolution across caecilians. This extensive variation also raises the question of degree of conservation of cranial modules (semi-autonomous subsets of highly-integrated traits) within this clade, allowing us to assess the importance of modular organisation in shaping morphological evolution. We used an intensive surface geometric morphometric approach to quantify cranial morphological variation across all 32 extant caecilian genera. We defined 16 cranial regions using 53 landmarks and 687 curve and 729 surface sliding semilandmarks. With these unprecedented high-dimensional data, we analysed cranial shape and modularity across caecilians assessing phylogenetic, allometric and ecological influences on cranial evolution, as well as investigating the relationships among integration, evolutionary rate, and morphological disparity. Results: We found highest support for a ten-module model, with greater integration of the posterior skull. Phylogenetic signal was significant (Kmult =0.87,p < 0.01), but stronger in anterior modules, while allometric influences were also significant (R2 =0.16,p < 0.01), but stronger posteriorly.
    [Show full text]
  • 71St Annual Meeting Society of Vertebrate Paleontology Paris Las Vegas Las Vegas, Nevada, USA November 2 – 5, 2011 SESSION CONCURRENT SESSION CONCURRENT
    ISSN 1937-2809 online Journal of Supplement to the November 2011 Vertebrate Paleontology Vertebrate Society of Vertebrate Paleontology Society of Vertebrate 71st Annual Meeting Paleontology Society of Vertebrate Las Vegas Paris Nevada, USA Las Vegas, November 2 – 5, 2011 Program and Abstracts Society of Vertebrate Paleontology 71st Annual Meeting Program and Abstracts COMMITTEE MEETING ROOM POSTER SESSION/ CONCURRENT CONCURRENT SESSION EXHIBITS SESSION COMMITTEE MEETING ROOMS AUCTION EVENT REGISTRATION, CONCURRENT MERCHANDISE SESSION LOUNGE, EDUCATION & OUTREACH SPEAKER READY COMMITTEE MEETING POSTER SESSION ROOM ROOM SOCIETY OF VERTEBRATE PALEONTOLOGY ABSTRACTS OF PAPERS SEVENTY-FIRST ANNUAL MEETING PARIS LAS VEGAS HOTEL LAS VEGAS, NV, USA NOVEMBER 2–5, 2011 HOST COMMITTEE Stephen Rowland, Co-Chair; Aubrey Bonde, Co-Chair; Joshua Bonde; David Elliott; Lee Hall; Jerry Harris; Andrew Milner; Eric Roberts EXECUTIVE COMMITTEE Philip Currie, President; Blaire Van Valkenburgh, Past President; Catherine Forster, Vice President; Christopher Bell, Secretary; Ted Vlamis, Treasurer; Julia Clarke, Member at Large; Kristina Curry Rogers, Member at Large; Lars Werdelin, Member at Large SYMPOSIUM CONVENORS Roger B.J. Benson, Richard J. Butler, Nadia B. Fröbisch, Hans C.E. Larsson, Mark A. Loewen, Philip D. Mannion, Jim I. Mead, Eric M. Roberts, Scott D. Sampson, Eric D. Scott, Kathleen Springer PROGRAM COMMITTEE Jonathan Bloch, Co-Chair; Anjali Goswami, Co-Chair; Jason Anderson; Paul Barrett; Brian Beatty; Kerin Claeson; Kristina Curry Rogers; Ted Daeschler; David Evans; David Fox; Nadia B. Fröbisch; Christian Kammerer; Johannes Müller; Emily Rayfield; William Sanders; Bruce Shockey; Mary Silcox; Michelle Stocker; Rebecca Terry November 2011—PROGRAM AND ABSTRACTS 1 Members and Friends of the Society of Vertebrate Paleontology, The Host Committee cordially welcomes you to the 71st Annual Meeting of the Society of Vertebrate Paleontology in Las Vegas.
    [Show full text]
  • Early Tetrapod Relationships Revisited
    Biol. Rev. (2003), 78, pp. 251–345. f Cambridge Philosophical Society 251 DOI: 10.1017/S1464793102006103 Printed in the United Kingdom Early tetrapod relationships revisited MARCELLO RUTA1*, MICHAEL I. COATES1 and DONALD L. J. QUICKE2 1 The Department of Organismal Biology and Anatomy, The University of Chicago, 1027 East 57th Street, Chicago, IL 60637-1508, USA ([email protected]; [email protected]) 2 Department of Biology, Imperial College at Silwood Park, Ascot, Berkshire SL57PY, UK and Department of Entomology, The Natural History Museum, Cromwell Road, London SW75BD, UK ([email protected]) (Received 29 November 2001; revised 28 August 2002; accepted 2 September 2002) ABSTRACT In an attempt to investigate differences between the most widely discussed hypotheses of early tetrapod relation- ships, we assembled a new data matrix including 90 taxa coded for 319 cranial and postcranial characters. We have incorporated, where possible, original observations of numerous taxa spread throughout the major tetrapod clades. A stem-based (total-group) definition of Tetrapoda is preferred over apomorphy- and node-based (crown-group) definitions. This definition is operational, since it is based on a formal character analysis. A PAUP* search using a recently implemented version of the parsimony ratchet method yields 64 shortest trees. Differ- ences between these trees concern: (1) the internal relationships of aı¨stopods, the three selected species of which form a trichotomy; (2) the internal relationships of embolomeres, with Archeria
    [Show full text]