DOCSLIB.ORG

Pancrustacea

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Pancrustacea MYRIAPODS CENTIPEDES ▸ Subphylum Myriapoda ▸ Class Chilopoda ▸ Two tagmata: head and trunk ▸ tracheae with spiracles ▸ Maxillipeds CHAPTER 14 MYRIAPODA Scolopendra heros, Texas up to 9 inches in length MYRIAPODS MILLIPEDES ▸ Class Diplopoda — ▸ Two tagmata: head (with ocelli) and trunk ▸ tracheae ▸ Detritivores or herbivores ▸ some defensively toxic House centipede -- introduced species MYRIAPODS OTHER MYRIAPODS ▸ Classes Pauropoda and Symphyla— ▸ Centipede-like in appearance ▸ limbs on each segment ▸ soft-bodied symphilid phylogeny of myriapoda pauropod from Edgecombe, G. D. and Giribet, G., 2002 MANDIBULATA? CURRENT PHYLOGENETIC IDEAS ARTHROPODA ▸ Clade Mandibulata Hexapoda (subphylum?) ▸ Myriapoda Branchiopoda PANCRUSTACEA ▸ Pancrustacea Malacostraca ▸ Hexapods? Myriapoda ▸ Regier, et al (2010) MANDIBULATA CHAPTER 14, PART 3 ▸ long branch attraction? Chelicerata ▸ long branches may show Onychophora erroneous affinities ▸ may increase likelihood of Tardigrada convergences CRUSTACEA Nemata adapted from Rota-Stabelli, et al (2010) CRUSTACEANS CRUSTACEANS ▸ Anatomy PANCRUSTACEA ▸ Three tagmata: head, thorax, abdomen ▸ Subphylum Pancrustacea (crustacea)— ▸ Heavily calcified exoskeleton ▸ aquatic, terrestrial, many are planktonic ▸ carapace ▸ usually dioecious, sometimes monoecious, sometimes ▸ Two pairs of antennae parthenogenic Cephalothorax ▸ nauplius antennule ▸ carapace three pairs appendages, Abdomen ▸ first antennae antenna ▸ second antennae pleopods ▸ mandibles cheliped walking legs (pereopods) ▸ medial eye 1 ▸ zoea 2 5 3 4 CRUSTACEANS CRUSTACEANS ▸ Ancestrally biramous appendages ▸ open circulatory system like all arthropods ▸ Basal protopod ▸ hemolymph ▸ lateral exopod ▸ hemocyanin or hemoglobin ▸ medial endopod branches ▸ arteries, hemocoels, venus sinuses, ostia, heart ▸ epipod ▸ coelom greatly reduced ▸ gills for gas exchange PROTOPOD body wall heart branchiostegite EXOPOD stomach gonad digestive gland ENDOPOD green gland CRUSTACEANS PANCRUSTACEA ▸ digestion end sac carapace ▸ cardiac stomach, pyloric stomach TAXONOMY ▸ excretion ▸ CLASS REMIPEDIA antennule ▸ gills trunk labyrinth ▸ many ancestral antenna appendages ▸ green gland nephridial canal features bladder ▸ CLASS CEPHALOCARIDA ▸ also lots of heart plesiomorphies stomach gonad ▸ monoecious digestive gland green gland PANCRUSTACEA PANCRUSTACEA ▸ CLASS OSTRACODA ▸ CLASS BRANCHIOPODA ▸ phyllopodia ▸ Mostly freshwater forms ▸ Order Cladocera [Diplostraca] PANCRUSTACEA ▸ CLASS COPEPODA ▸ Very abundant PANCRUSTACEA PANCRUSTACEA thoracic appendages (cirri) ▸ CLASS PENTASTOMIDA ▸ CLASS CIRRIPEDIA tergum ▸ formerly placed in a separate phylum ▸ no chitinous exoskeleton; scutum ▸ calcareous plates ▸ Filter feed with cirri antennules PANCRUSTACEA PANCRUSTACEA ▸ CLASS MALACOSTRACA ▸ limbs ▸ most of the large crustaceans ▸ 8-head(feeding/sensory), 5-thorax(walking), 6- abdomen(swim/respire/reprod.) ▸ gills ▸ branchiostegite “shield” PANCRUSTACEA PANCRUSTACEA ▸ Pillbugs -- “rollypolly” ▸ pseudotracheae PHYLOGENY ▸ Crustacean phylogeny ▸ lots of disagreement/questions SOWBUG ▸ insects --> xenocarida ▸ just fancy crustaceans? PILLBUG GIANT MARINE ISOPOD Bjoern M. von Reumont et al. Mol Biol Evol 2012;29:1031-1045 .
Load more

Recommended publications
  • Going Deeper Into High and Low Phylogenetic Relationships of Protura
    G C A T T A C G G C A T genes Article Going Deeper into High and Low Phylogenetic Relationships of Protura 1, , 2,3, 3 1 1 Antonio Carapelli * y , Yun Bu y, Wan-Jun Chen , Francesco Nardi , Chiara Leo , Francesco Frati 1 and Yun-Xia Luan 3,4,* 1 Department of Life Sciences, University of Siena, Via A. Moro 2, 53100 Siena, Italy; [email protected] (F.N.); [email protected] (C.L.); [email protected] (F.F.) 2 Natural History Research Center, Shanghai Natural History Museum, Shanghai Science & Technology Museum, Shanghai 200041, China; [email protected] 3 Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China; [email protected] 4 Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou 510631, China * Correspondence: [email protected] (A.C.); [email protected] (Y.-X.L.); Tel.: +39-0577-234410 (A.C.); +86-18918100826 (Y.-X.L.) These authors contributed equally to this work. y Received: 16 March 2019; Accepted: 5 April 2019; Published: 10 April 2019 Abstract: Proturans are small, wingless, soil-dwelling arthropods, generally associated with the early diversification of Hexapoda. Their bizarre morphology, together with conflicting results of molecular studies, has nevertheless made their classification ambiguous. Furthermore, their limited dispersal capability (due to the primarily absence of wings) and their euedaphic lifestyle have greatly complicated species-level identification.
    [Show full text]
  • Phylogenomic Resolution of Sea Spider Diversification Through Integration Of
    bioRxiv preprint doi: https://doi.org/10.1101/2020.01.31.929612; this version posted February 2, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Phylogenomic resolution of sea spider diversification through integration of multiple data classes 1Jesús A. Ballesteros†, 1Emily V.W. Setton†, 1Carlos E. Santibáñez López†, 2Claudia P. Arango, 3Georg Brenneis, 4Saskia Brix, 5Esperanza Cano-Sánchez, 6Merai Dandouch, 6Geoffrey F. Dilly, 7Marc P. Eleaume, 1Guilherme Gainett, 8Cyril Gallut, 6Sean McAtee, 6Lauren McIntyre, 9Amy L. Moran, 6Randy Moran, 5Pablo J. López-González, 10Gerhard Scholtz, 6Clay Williamson, 11H. Arthur Woods, 12Ward C. Wheeler, 1Prashant P. Sharma* 1 Department of Integrative Biology, University of Wisconsin–Madison, Madison, WI, USA 2 Queensland Museum, Biodiversity Program, Brisbane, Australia 3 Zoologisches Institut und Museum, Cytologie und Evolutionsbiologie, Universität Greifswald, Greifswald, Germany 4 Senckenberg am Meer, German Centre for Marine Biodiversity Research (DZMB), c/o Biocenter Grindel (CeNak), Martin-Luther-King-Platz 3, Hamburg, Germany 5 Biodiversidad y Ecología Acuática, Departamento de Zoología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain 6 Department of Biology, California State University-Channel Islands, Camarillo, CA, USA 7 Départment Milieux et Peuplements Aquatiques, Muséum national d’Histoire naturelle, Paris, France 8 Institut de Systématique, Emvolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Concarneau, France 9 Department of Biology, University of Hawai’i at Mānoa, Honolulu, HI, USA Page 1 of 31 bioRxiv preprint doi: https://doi.org/10.1101/2020.01.31.929612; this version posted February 2, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder.
    [Show full text]
  • Saproxylic Collembola in Forests of Northern Hemisphere
    The hidden and unknown biodiversity of dead wood: Saproxylic Collembola in forests of Northern hemisphere dr Adrian Smolis Wrocław Uniwersity Poland Springtails (Collembola) – systematic position • Phyllum: Arthropoda Latreille, 1829 • Subphyllum: two concepts – Pancrustacea Zrzavy & Stys, 1997 (hexapods and crustaceans) Atelocerata Heymons, 1901 (hexapods and myriapods) • Superclass: Hexapoda Blainville, 1816 (Insecta sensu lato) • „Apterygota” • „Entognatha” – Collembola, Protura and Diplura Class: Collembola Lubbock, 1870 Rhyniella praecursor (the early Devon ca 400 milion years ago, the first and oldest hexapods, terrestial arthropods or animal?) Springtails – morphology • Body size: 0.12-17 mm; body shape: elongate, cylindrical, flattened or globular; colour:uniformly pigmented, bluish or white. • three tagmae: head (antennae and eyes), thorax (legs) and abdomen (6 segments). • Unique structures: postanntennal organ, ventral tube and jumping organ. Springtails – morphology Springtails – morphology Springtails – ecology • direct development • food (polyphagous): fungal hyphae, decaying vegetation, organic detriturus, algae, lichens, micro-organisms, some genera and species carnivorous. • very widespread and abundant group, almost all habitats, huge aggregates on snow (common name „snow fleas”). • life-forms: atmobionts, hemiedaphons and euedaphons. • important roles in nutrient recycling, initial stages of decomposition, structure of soils, growth of mycorhizae, food of many predators. • ca 8000 species and 600 genera described. Springtails
    [Show full text]
  • Ecdysozoan Phylogeny and Bayesian Inference: First Use of Nearly Complete 28S and 18S Rrna Gene Sequences to Classify the Arthro
    MOLECULAR PHYLOGENETICS AND EVOLUTION Molecular Phylogenetics and Evolution 31 (2004) 178–191 www.elsevier.com/locate/ympev Ecdysozoan phylogeny and Bayesian inference: first use of nearly complete 28S and 18S rRNA gene sequences to classify the arthropods and their kinq Jon M. Mallatt,a,* James R. Garey,b and Jeffrey W. Shultzc a School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA b Department of Biology, University of South Florida, 4202 East Fowler Ave. SCA110, Tampa, FL 33620, USA c Department of Entomology, University of Maryland, College Park, MD 20742, USA Received 4 March 2003; revised 18 July 2003 Abstract Relationships among the ecdysozoans, or molting animals, have been difficult to resolve. Here, we use nearly complete 28S + 18S ribosomal RNA gene sequences to estimate the relations of 35 ecdysozoan taxa, including newly obtained 28S sequences from 25 of these. The tree-building algorithms were likelihood-based Bayesian inference and minimum-evolution analysis of LogDet-trans- formed distances, and hypotheses were tested wth parametric bootstrapping. Better taxonomic resolution and recovery of estab- lished taxa were obtained here, especially with Bayesian inference, than in previous parsimony-based studies that used 18S rRNA sequences (or 18S plus small parts of 28S). In our gene trees, priapulan worms represent the basal ecdysozoans, followed by ne- matomorphs, or nematomorphs plus nematodes, followed by Panarthropoda. Panarthropoda was monophyletic with high support, although the relationships among its three phyla (arthropods, onychophorans, tardigrades) remain uncertain. The four groups of arthropods—hexapods (insects and related forms), crustaceans, chelicerates (spiders, scorpions, horseshoe crabs), and myriapods (centipedes, millipedes, and relatives)—formed two well-supported clades: Hexapoda in a paraphyletic crustacea (Pancrustacea), and ÔChelicerata + MyriapodaÕ (a clade that we name ÔParadoxopodaÕ).
    [Show full text]
  • Arthropod Fossil Data Increase Congruence of Morphological and Molecular Phylogenies
    ARTICLE Received 14 Jan 2013 | Accepted 21 Aug 2013 | Published 30 Sep 2013 DOI: 10.1038/ncomms3485 Arthropod fossil data increase congruence of morphological and molecular phylogenies David A. Legg1,2,3, Mark D. Sutton1 & Gregory D. Edgecombe2 The relationships of major arthropod clades have long been contentious, but refinements in molecular phylogenetics underpin an emerging consensus. Nevertheless, molecular phylogenies have recovered topologies that morphological phylogenies have not, including the placement of hexapods within a paraphyletic Crustacea, and an alliance between myriapods and chelicerates. Here we show enhanced congruence between molecular and morphological phylogenies based on 753 morphological characters for 309 fossil and Recent panarthropods. We resolve hexapods within Crustacea, with remipedes as their closest extant relatives, and show that the traditionally close relationship between myriapods and hexapods is an artefact of convergent character acquisition during terrestrialisation. The inclusion of fossil morphology mitigates long-branch artefacts as exemplified by pycnogonids: when fossils are included, they resolve with euchelicerates rather than as a sister taxon to all other euarthropods. 1 Department of Earth Sciences and Engineering, Royal School of Mines, Imperial College London, London SW7 2AZ, UK. 2 Department of Earth Sciences, The Natural History Museum, London SW7 5BD, UK. 3 Oxford University Museum of Natural History, Oxford OX1 3PW, UK. Correspondence and requests for materials should be addressed to D.A.L. (email: [email protected]). NATURE COMMUNICATIONS | 4:2485 | DOI: 10.1038/ncomms3485 | www.nature.com/naturecommunications 1 & 2013 Macmillan Publishers Limited. All rights reserved. ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/ncomms3485 rthropods are diverse, disparate, abundant and ubiqui- including all major extinct and extant panarthropod groups.
    [Show full text]
  • Mini-Review an Insect-Specific System for Terrestrialization Laccase
    Insect Biochemistry and Molecular Biology 108 (2019) 61–70 Contents lists available at ScienceDirect Insect Biochemistry and Molecular Biology journal homepage: www.elsevier.com/locate/ibmb Mini-review an insect-specific system for terrestrialization: Laccase- mediated cuticle formation T ∗ Tsunaki Asano , Yosuke Seto, Kosei Hashimoto, Hiroaki Kurushima Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, 192-0397, Japan ABSTRACT Insects are often regarded as the most successful group of animals in the terrestrial environment. Their success can be represented by their huge biomass and large impact on ecosystems. Among the factors suggested to be responsible for their success, we focus on the possibility that the cuticle might have affected the process of insects’ evolution. The cuticle of insects, like that of other arthropods, is composed mainly of chitin and structural cuticle proteins. However, insects seem to have evolved a specific system for cuticle formation. Oxidation reaction of catecholamines catalyzed by a copper enzyme, laccase, is the key step in the metabolic pathway for hardening of the insect cuticle. Molecular phylogenetic analysis indicates that laccase functioning in cuticle sclerotization has evolved only in insects. In this review, we discuss a theory on how the insect-specific “laccase” function has been advantageous for establishing their current ecological position as terrestrial animals. 1. Introduction the cuticle hardens after molting in crustaceans and diplopods (Shaw, 1968; Barnes, 1982; Nagasawa,
    [Show full text]
  • Evolution and Multiple Roles of the Pancrustacea Specific Transcription Factor Zelda in Insects
    RESEARCH ARTICLE Evolution and multiple roles of the Pancrustacea specific transcription factor zelda in insects Lupis Ribeiro1,2, Vito ria Tobias-Santos1, Daniele Santos1, Felipe Antunes1, Geo rgia Feltran1, Jackson de Souza Menezes1, L. Aravind3, Thiago M. Venancio2*, Rodrigo Nunes da Fonseca1* 1 LaboratoÂrio Integrado de BioquõÂmica Hatisaburo Masuda, NuÂcleo em Ecologia e Desenvolvimento SoÂcioAmbiental de Macae (NUPEM), Campus UFRJ MacaeÂ, Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM, MacaeÂ, Brazil, 2 LaboratoÂrio de QuõÂmica e FuncËão de ProteõÂnas e a1111111111 PeptõÂdeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense Darcy a1111111111 Ribeiro, Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular - INCT-EM, Rio de Janeiro, a1111111111 Brazil, 3 National Center for Biotechnology Information, National Library of Medicine, National Institutes of a1111111111 Health, Bethesda, Maryland, United States of America a1111111111 * [email protected] (TMV); [email protected] (RNdF) Abstract OPEN ACCESS Gene regulatory networks (GRNs) evolve as a result of the coevolutionary processes acting Citation: Ribeiro L, Tobias-Santos V, Santos D, Antunes F, Feltran G, de Souza Menezes J, et al. on transcription factors (TFs) and the cis-regulatory modules they bind. The zinc-finger TF (2017) Evolution and multiple roles of the zelda (zld) is essential for the maternal-to-zygotic transition (MZT) in Drosophila melanoga- Pancrustacea specific transcription factor zelda in ster, where it directly binds over thousand cis-regulatory modules to regulate chromatin insects. PLoS Genet 13(7): e1006868. https://doi. org/10.1371/journal.pgen.1006868 accessibility. D. melanogaster displays a long germ type of embryonic development, where all segments are simultaneously generated along the whole egg.
    [Show full text]
  • Mitochondrial Genome Diversity and Evolution in Branchiopoda (Crustacea) Andrea Luchetti1* , Giobbe Forni1, Alyza M
    Luchetti et al. Zoological Letters (2019) 5:15 https://doi.org/10.1186/s40851-019-0131-5 RESEARCHARTICLE Open Access Mitochondrial genome diversity and evolution in Branchiopoda (Crustacea) Andrea Luchetti1* , Giobbe Forni1, Alyza M. Skaist2, Sarah J. Wheelan2 and Barbara Mantovani1 Abstract Background: The crustacean class Branchiopoda includes fairy shrimps, clam shrimps, tadpole shrimps, and water fleas. Branchiopods, which are well known for their great variety of reproductive strategies, date back to the Cambrian and extant taxa can be mainly found in freshwater habitats, also including ephemeral ponds. Mitochondrial genomes of the notostracan taxa Lepidurus apus lubbocki (Italy), L. arcticus (Iceland) and Triops cancriformis (an Italian and a Spanish population) are here characterized for the first time and analyzed together with available branchiopod mitogenomes. Results: Overall, branchiopod mitogenomes share the basic structure congruent with the ancestral Pancrustacea model. On the other hand, rearrangements involving tRNAs and the control region are observed among analyzed taxa. Remarkably, an unassigned region in the L. apus lubbocki mitogenome showed a chimeric structure, likely resulting from a non-homologous recombination event between the two flanking trnC and trnY genes. Notably, Anostraca and Onychocaudata mitogenomes showed increased GC content compared to both Notostraca and the common ancestor, and a significantly higher substitution rate, which does not correlate with selective pressures, as suggested by dN/dS values. Conclusions: Branchiopod mitogenomes appear rather well-conserved, although gene rearrangements have occurred. For the first time, it is reported a putative non-homologous recombination event involving a mitogenome, which produced a pseudogenic tRNA sequence. In addition, in line with data in the literature, we explain the higher substitution rate of Anostraca and Onychocaudata with the inferred GC substitution bias that occurred during their evolution.
    [Show full text]
  • Morphological Evidence Supporting the Common Lineage Between Crustacea and Hexapoda Dom Apicella, Aaron Codling, Robert Keller, Steve Koppleman
    Euglena: 2013 Morphological Evidence Supporting The Common Lineage between Crustacea and Hexapoda Dom Apicella, Aaron Codling, Robert Keller, Steve Koppleman Department of Biology, Susquehanna University Selinsgrove, PA 17870. Abstract While evidence has been found that strongly supports the theory that Hexapoda is a subphylum that arose due to the branching of a group within Crustacea, our study provides sufficient support for the hypothesis of the direct lineage from Crustacea to Hexapoda. Our research is based on the hypothesis that Hexapoda is a sister group of Crustacea. Evidence found within both our Maximum Likelihood and Maximum Parsimony Phylogenetic Trees points to a closely-related dichotomy between Crustacea and Hexapoda. Likewise, these trees enables the group to pinpoint the gains and losses of specific characters. Please cite this article as: Apicella, D., A. Codling, R. Keller, and S. Koppleman. 2013. Morphological evidence supporting the common lineage between Crustacea and Hexapoda. Euglega. doi:/euglena. 1(1): 26-33. Introduction Moreover, cladistics has been used to further In terms of Arthropod phylogeny, it is understand the lineage of hexapods from crustaceans. accepted that Hexapoda, a subphylum characterized In this study, we interpret five characters and their by the presence of six attached walking legs to the particular character states through the Tetraconata thorax, are derived from Myriapoda, a subphylum clade’s lineage. We believe that there is a direct defined by their one or two pairs of walking legs for evolutionary connection between crustaceans and most body segments, (e.g. Wheeler et al. 2001); hexapods. Within the lineage of Crustacea, taxa however, analyses done over the last several years on branched off and became terrestrial, eventually morphological and molecular characters of various forming the subphylum Hexapoda.
    [Show full text]
  • Support for Remipedia As the Possible Sister Group of Hexapoda Bjoern M
    Pancrustacean Phylogeny in the Light of New Phylogenomic Data: Support for Remipedia as the Possible Sister Group of Hexapoda Bjoern M. von Reumont,*,1 Ronald A. Jenner,2 Matthew A. Wills,3 Emiliano Dell’Ampio,4 Gu¨nther Pass,4 Ingo Ebersberger,5 Benjamin Meyer,6 Stefan Koenemann,7 Thomas M. Iliffe,8 Alexandros Stamatakis,9 Oliver Niehuis,1 Karen Meusemann,1 and Bernhard Misof1 1Zoologisches Forschungsmuseum Alexander Koenig, Zentrum fu¨r Molekulare Biodiversita¨tsforschung, Bonn, Germany 2Department of Zoology, The Natural History Museum, London, United Kingdom 3Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom 4Department of Evolutionary Biology, University of Vienna, Vienna, Austria 5Center for Integrative Bioinformatics Vienna (CIBIV), University of Vienna, Medical University of Vienna, University of Veterinary Medicine Vienna, Vienna, Austria 6Biozentrum Grindel und Zoologisches Museum, Universita¨t Hamburg, Hamburg, Germany 7Section Biology, Science and Technology, University of Siegen, Siegen, Germany 8Department of Marine Biology, Texas A&M University at Galveston 9The Exelixis Lab, Scientific Computing Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany *Corresponding author: E-mail: [email protected]. Associate editor: Billie Swalla Abstract Remipedes are a small and enigmatic group of crustaceans, first described only 30 years ago. Analyses of both morphological and molecular data have recently suggested a close relationship between Remipedia and Hexapoda. If true, the remipedes occupy an important position in pancrustacean evolution and may be pivotal for understanding the evolutionary history of crustaceans and hexapods. However, it is important to test this hypothesis using new data and new types of analytical approaches. Here, we assembled a phylogenomic data set of 131 taxa, incorporating newly generated 454 expressed sequence tag (EST) data from six species of crustaceans, representing five lineages (Remipedia, Laevicaudata, Spinicaudata, Ostracoda, and Malacostraca).
    [Show full text]
  • ARTHROPODS and the Origins of Insects ARTHROPODA and Related Phyla
    ARTHROPODS and the origins of insects ARTHROPODA and related phyla Phylum Annelida Phylum Gastrotricha Phylum Nematoda Phylum Nematomorpha Phylum Priapulida Phylum Kinorhyncha Phylum Loricifera Phylum Onychophora Phylum Tardigrada Phylum Arthropoda Phylum Annelida - segmented worms Marine, freshwater, & terrestrial segmented worms. Cosmopolitan, very diverse. Polychaeta (mostly marine), Oligochaeta (earthworms etc.) and Hirudinea (leeches). 1 mm - 3 m. 15,000 species. Phylum Gastrotricha Microscopic (0.06-3 mm) unsegmented free-living, aquatic worms. Marine and freshwater. Mieofauna and periphyton. Very abundant. Microphagous detritivores. Ca. 750 species. Phylum Nematoda - roundworms Microscopic to very long (up to 100 cm) unsegmented worms. Free-living and parasitic (intestinal roundworms, hookworms, pinworms, trichinosis), many pathogens of animals and plants (important to agriculture). Ubiquitous, very abundant. Marine, freshwater, terrestrial. Ca. 80,000 species. Phylum Nematomorpha - horsehair worms Very long, thin unsegmented worms (1 cm - 1 m). Immature forms parasitic in insects, sowbugs; adults occur in freshwater. Ca. 350 species. Phylum Priapulida Marine segmented worms (several mm to 15 cm), with extensible, spiny proboscis. Ca. 15 species known. Predaceous. Live in mud on bottom of shallow seas (esp. cold oceans). Phylum Kinorhyncha Microscopic marine segmented worms. Bristly, spiny, with crown of curved spines on head. Mouth bears piercing stylets. Feed on diatoms, protozoans, detritus. Muddy bottoms and meiofauna. Ca. 150 species. Phylum Loricifera Microscopic marine animals (1 micron -1 mm). Mieofauna. Only discovered in 1983. 25 species. Phylum Onychophora - velvet worms Terrestrial, wormlike. Elongate. Segmented, each with pair of short legs. Antenna-like papillae on head. Possess tracheae. Live on forest floor of tropical and southern temperate rainforest forest. Predaceous.
    [Show full text]
  • Dating the Origin of the Major Lineages of Branchiopoda
    Available online at www.sciencedirect.com ScienceDirect Palaeoworld 25 (2016) 303–317 Dating the origin of the major lineages of Branchiopoda a,∗ b a,∗ Xiao-Yan Sun , Xuhua Xia , Qun Yang a LPS, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China b Department of Biology, University of Ottawa, Ontario K1N 6N5, Canada Received 3 June 2014; received in revised form 30 October 2014; accepted 3 February 2015 Available online 14 February 2015 Abstract Despite the well-established phylogeny and good fossil record of branchiopods, a consistent macro-evolutionary timescale for the group remains elusive. This study focuses on the early branchiopod divergence dates where fossil record is extremely fragmentary or missing. On the basis of a large genomic dataset and carefully evaluated fossil calibration points, we assess the quality of the branchiopod fossil record by calibrating the tree against well-established first occurrences, providing paleontological estimates of divergence times and completeness of their fossil record. The maximum age constraints were set using a quantitative approach of Marshall (2008). We tested the alternative placements of Yicaris and Wujicaris in the referred arthropod tree via the likelihood checkpoints method. Divergence dates were calculated using Bayesian relaxed molecular clock and penalized likelihood methods. Our results show that the stem group of Branchiopoda is rooted in the late Neoproterozoic (563 ± 7 Ma); the crown-Branchiopoda diverged during middle Cambrian to Early Ordovician (478–512 Ma), likely representing the origin of the freshwater biota; the Phyllopoda clade diverged during Ordovician (448–480 Ma) and Diplostraca during Late Ordovician to early Silurian (430–457 Ma).
    [Show full text]