Lab Exercise 4 Porifera Cnidaria Platyhelminthes

Total Page：16

File Type：pdf, Size：1020Kb

Lab Exercise 4 Porifera Cnidaria Platyhelminthes Organization in Animals • Cellular level: Random assembly of cells • Tissue level: Cells connected to form distinct tissues • Organ level: Tissues connected to form organs Levels of Biological Organization • Organ system level – All more advanced organisms – Multiple organ systems working together form an complex organism 1 Biological Symmetry • Radial Symmetry – Body can be divided into mirror image halves through the center –Examples • Mature Cnidarians Biological Symmetry • Bilateral Symmetry – Body is divisible into left and right halves by a single plane only –Examples •Flatworms • Arthropods • Vertebrates Biological Symmetry • Asymmetry – Body cannot be divided to produce mirror image halves –Example • Porifera 2 Embryonic Development Cell Cleavage Blastula Gastrula Gastrula Gastrula Gastrula (Diploblastic) (Triploblastic) Ectoderm Endoderm Mesoderm Archenteron- Space within endoderm Blastopore Blastopore Archenteron: becomes adult digestive tract Blastopore: becomes the mouth or anus Phylum Porifera • Diploblastic • Asymmetrical • No digestive tissue- absorbs particles from water 3 Phylum Porifera Ostium • Ostium • Choanocytes • Amoebocyte • Spicules • Spongocoel • Osculum Phylum Porifera— 3 Body Plans Asconoid Syconoid Leuconoid Phylum Cnidaria • Characteristics – Radial symmetry – Cnidocytes – Simple nerve net – Life cycle alternates between two forms • Medusa •Polyp 4 Cnidaria - body plan Polyp Medusa Cnidocyte Operculum Cnidocil Cnidocyte Nematocyst Class Hydrozoa - Hydras • Polyps are the mature form • Individuals or colonies • Portuguese Man-o- war special colony 5 Class Hydrozoa - Hydras • Prey on zooplankton • You will observe Hydra feeding on Daphnia – Look at locomotion http://www.youtube.com/watch?v=Kukv0AtIVdU Class Scyphozoa: Jellyfish •Marine Mesoglea Gastric pouch Gonad • Medusas: dominant life form • Aurelia Tentacles Ectoderm Endoderm Oral arms 6 Class Anthozoa • Anemones and corals • Most complex cnidarians • Always polyps • Symbiosis with dinoflagellates Class Anthozoa - Anemones pharynx coelentron basal http://www.emc.maricopa.edu/faculty/farabee/biobk/anemone.gif Phylum Platyhelminthes- Flat worms •Triploblastic • Bilateral Symmetry •Organs • Sac-like gut •Acoelmate –No cavity • Monoecious 7 Class Turbellaria– Planarian spp. • Free living • Cephalization- – You can see where you are going – Brain center- coordinate movement • Bilateral Symmetry = efficient movement Class Turbellaria Planarian cross-section Ectoderm Mesoderm Endoderm Pharyngeal cavity Pharynx Gut Gut Lumen of the pharynx Parenchyma Class Trematoda-Flukes • Life cycle with multiple hosts • Parasites – Opisthorchis sinensis- Human liver fluke 8 Class Cestoda- Tapeworms • Thin, ribbon-like • Sections = proglottids • Parasites • 1 or 2 Hosts Class Hydrazoa Gonangia Hydranth Class Scyphozoa 9 Class Trematoda • Life cycle with multiple hosts 10.

Copy Link

Recommended publications

Sexual Reproduction 7.2: Meiosis 7.3: Errors in Meiosis
Concepts of Biology Chapter 6 | Reproduction at the Cellular Level 135 6 | REPRODUCTION AT THE CELLULAR LEVEL Figure 6.1 A sea urchin begins life as a single cell that (a) divides to form two cells, visible by scanning electron microscopy. After four rounds of cell division, (b) there are 16 cells, as seen in this SEM image. After many rounds of cell division, the individual develops into a complex, multicellular organism, as seen in this (c) mature sea urchin. (credit a: modification of work by Evelyn Spiegel, Louisa Howard; credit b: modification of work by Evelyn Spiegel, Louisa Howard; credit c: modification of work by Marco Busdraghi; scale-bar data from Matt Russell) Chapter Outline 6.1: The Genome 6.2: The Cell Cycle 6.3: Cancer and the Cell Cycle 6.4: Prokaryotic Cell Division Introduction The individual sexually reproducing organism—including humans—begins life as a fertilized egg, or zygote. Trillions of cell divisions subsequently occur in a controlled manner to produce a complex, multicellular human. In other words, that original single cell was the ancestor of every other cell in the body. Once a human individual is fully grown, cell reproduction is still necessary to repair or regenerate tissues. For example, new blood and skin cells are constantly being produced. All multicellular organisms use cell division for growth, and in most cases, the maintenance and repair of cells and tissues. Single-celled organisms use cell division as their method of reproduction. 6.1 | The Genome By the end of this section, you will be able to: • Describe the prokaryotic and eukaryotic genome • Distinguish between chromosomes, genes, and traits The continuity of life from one cell to another has its foundation in the reproduction of cells by way of the cell cycle.
[Show full text]
The Evolution of Siphonophore Tentilla for Specialized Prey Capture in the Open Ocean
The evolution of siphonophore tentilla for specialized prey capture in the open ocean Alejandro Damian-Serranoa,1, Steven H. D. Haddockb,c, and Casey W. Dunna aDepartment of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520; bResearch Division, Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039; and cEcology and Evolutionary Biology, University of California, Santa Cruz, CA 95064 Edited by Jeremy B. C. Jackson, American Museum of Natural History, New York, NY, and approved December 11, 2020 (received for review April 7, 2020) Predator specialization has often been considered an evolutionary makes them an ideal system to study the relationships between “dead end” due to the constraints associated with the evolution of functional traits and prey specialization. Like a head of coral, a si- morphological and functional optimizations throughout the organ- phonophore is a colony bearing many feeding polyps (Fig. 1). Each ism. However, in some predators, these changes are localized in sep- feeding polyp has a single tentacle, which branches into a series of arate structures dedicated to prey capture. One of the most extreme tentilla. Like other cnidarians, siphonophores capture prey with cases of this modularity can be observed in siphonophores, a clade of nematocysts, harpoon-like stinging capsules borne within special- pelagic colonial cnidarians that use tentilla (tentacle side branches ized cells known as cnidocytes. Unlike the prey-capture apparatus of armed with nematocysts) exclusively for prey capture. Here we study most other cnidarians, siphonophore tentacles carry their cnidocytes how siphonophore specialists and generalists evolve, and what mor- in extremely complex and organized batteries (3), which are located phological changes are associated with these transitions.
[Show full text]
Number of Living Species in Australia and the World
Numbers of Living Species in Australia and the World 2nd edition Arthur D. Chapman Australian Biodiversity Information Services australia’s nature Toowoomba, Australia there is more still to be discovered… Report for the Australian Biological Resources Study Canberra, Australia September 2009 CONTENTS Foreword 1 Insecta (insects) 23 Plants 43 Viruses 59 Arachnida Magnoliophyta (flowering plants) 43 Protoctista (mainly Introduction 2 (spiders, scorpions, etc) 26 Gymnosperms (Coniferophyta, Protozoa—others included Executive Summary 6 Pycnogonida (sea spiders) 28 Cycadophyta, Gnetophyta under fungi, algae, Myriapoda and Ginkgophyta) 45 Chromista, etc) 60 Detailed discussion by Group 12 (millipedes, centipedes) 29 Ferns and Allies 46 Chordates 13 Acknowledgements 63 Crustacea (crabs, lobsters, etc) 31 Bryophyta Mammalia (mammals) 13 Onychophora (velvet worms) 32 (mosses, liverworts, hornworts) 47 References 66 Aves (birds) 14 Hexapoda (proturans, springtails) 33 Plant Algae (including green Reptilia (reptiles) 15 Mollusca (molluscs, shellfish) 34 algae, red algae, glaucophytes) 49 Amphibia (frogs, etc) 16 Annelida (segmented worms) 35 Fungi 51 Pisces (fishes including Nematoda Fungi (excluding taxa Chondrichthyes and (nematodes, roundworms) 36 treated under Chromista Osteichthyes) 17 and Protoctista) 51 Acanthocephala Agnatha (hagfish, (thorny-headed worms) 37 Lichen-forming fungi 53 lampreys, slime eels) 18 Platyhelminthes (flat worms) 38 Others 54 Cephalochordata (lancelets) 19 Cnidaria (jellyfish, Prokaryota (Bacteria Tunicata or Urochordata sea anenomes, corals) 39 [Monera] of previous report) 54 (sea squirts, doliolids, salps) 20 Porifera (sponges) 40 Cyanophyta (Cyanobacteria) 55 Invertebrates 21 Other Invertebrates 41 Chromista (including some Hemichordata (hemichordates) 21 species previously included Echinodermata (starfish, under either algae or fungi) 56 sea cucumbers, etc) 22 FOREWORD In Australia and around the world, biodiversity is under huge Harnessing core science and knowledge bases, like and growing pressure.
[Show full text]
Feeding-Dependent Tentacle Development in the Sea Anemone Nematostella Vectensis ✉ Aissam Ikmi 1,2 , Petrus J
ARTICLE https://doi.org/10.1038/s41467-020-18133-0 OPEN Feeding-dependent tentacle development in the sea anemone Nematostella vectensis ✉ Aissam Ikmi 1,2 , Petrus J. Steenbergen1, Marie Anzo 1, Mason R. McMullen2,3, Anniek Stokkermans1, Lacey R. Ellington2 & Matthew C. Gibson2,4 In cnidarians, axial patterning is not restricted to embryogenesis but continues throughout a prolonged life history filled with unpredictable environmental changes. How this develop- 1234567890():,; mental capacity copes with fluctuations of food availability and whether it recapitulates embryonic mechanisms remain poorly understood. Here we utilize the tentacles of the sea anemone Nematostella vectensis as an experimental paradigm for developmental patterning across distinct life history stages. By analyzing over 1000 growing polyps, we find that tentacle progression is stereotyped and occurs in a feeding-dependent manner. Using a combination of genetic, cellular and molecular approaches, we demonstrate that the crosstalk between Target of Rapamycin (TOR) and Fibroblast growth factor receptor b (Fgfrb) signaling in ring muscles defines tentacle primordia in fed polyps. Interestingly, Fgfrb-dependent polarized growth is observed in polyp but not embryonic tentacle primordia. These findings show an unexpected plasticity of tentacle development, and link post-embryonic body patterning with food availability. 1 Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany. 2 Stowers Institute for Medical Research, Kansas City, MO 64110,
[Show full text]
Animal Phylum Poster Porifera
Phylum PORIFERA CNIDARIA PLATYHELMINTHES ANNELIDA MOLLUSCA ECHINODERMATA ARTHROPODA CHORDATA Hexactinellida -- glass (siliceous) Anthozoa -- corals and sea Turbellaria -- free-living or symbiotic Polychaetes -- segmented Gastopods -- snails and slugs Asteroidea -- starfish Trilobitomorpha -- tribolites (extinct) Urochordata -- tunicates Groups sponges anemones flatworms (Dugusia) bristleworms Bivalves -- clams, scallops, mussels Echinoidea -- sea urchins, sand Chelicerata Cephalochordata -- lancelets (organisms studied in detail in Demospongia -- spongin or Hydrazoa -- hydras, some corals Trematoda -- flukes (parasitic) Oligochaetes -- earthworms (Lumbricus) Cephalopods -- squid, octopus, dollars Arachnida -- spiders, scorpions Mixini -- hagfish siliceous sponges Xiphosura -- horseshoe crabs Bio1AL are underlined) Cubozoa -- box jellyfish, sea wasps Cestoda -- tapeworms (parasitic) Hirudinea -- leeches nautilus Holothuroidea -- sea cucumbers Petromyzontida -- lamprey Mandibulata Calcarea -- calcareous sponges Scyphozoa -- jellyfish, sea nettles Monogenea -- parasitic flatworms Polyplacophora -- chitons Ophiuroidea -- brittle stars Chondrichtyes -- sharks, skates Crustacea -- crustaceans (shrimp, crayfish Scleropongiae -- coralline or Crinoidea -- sea lily, feather stars Actinipterygia -- ray-finned fish tropical reef sponges Hexapoda -- insects (cockroach, fruit fly) Sarcopterygia -- lobed-finned fish Myriapoda Amphibia (frog, newt) Chilopoda -- centipedes Diplopoda -- millipedes Reptilia (snake, turtle) Aves (chicken, hummingbird) Mammalia
[Show full text]
Invertebrates Invertebrates: • Are Animals Without Backbones • Represent 95% of the Animal Kingdom Animal Diversity Morphological Vs
Invertebrates Invertebrates: • Are animals without backbones • Represent 95% of the animal kingdom Animal Diversity Morphological vs. Molecular Character Phylogeny? A tree is a hypothesis supported or not supported by evidence. Groupings change as new evidence become available. Sponges - Porifera Natural Bath Sponges – over-collected, now uncommon Sponges • Perhaps oldest animal phylum (Ctenphora possibly older) • may represent several old phyla, some now extinct ----------------Ctenophora? Sponges - Porifera • Mostly marine • Sessile animals • Lack true tissues; • Have only a few cell types, cells kind of independent • Most have no symmetry • Body resembles a sac perforated with holes, system of canals. • Strengthened by fibers of spongin, spicules Sponges have a variety of shapes Sponges Pores Choanocyte Amoebocyte (feeding cell) Skeletal Water fiber flow Central cavity Flagella Choanocyte in contact with an amoebocyte Sponges - Porifera • Sessile filter feeder • No mouth • Sac-like body, perforated by pores. • Interior lined by flagellated cells (choanocytes). Flagellated collar cells generate a current, draw water through the walls of the sponge where food is collected. • Amoeboid cells move around in the mesophyll and distribute food. Sponges - Porifera Grantia x.s. Sponge Reproduction Asexual reproduction • Fragmentation or by budding. • Sponges are capable of regeneration, growth of a whole from a small part. Sexual reproduction • Hermaphrodites, produce both eggs and sperm • Eggs and sperm released into the central cavity • Produces
[Show full text]
Hazardous Marine Life
JOIN US AT DAN.ORG HAZARDOUS MARINE LIFE STINGS Cnidarians (nematocyst-carrying species) are HEALTH & DIVING REFERENCE SERIES responsible for more evenomations than any other marine phylum. These organisms contain stinging cells called cnidocyte that excel at venom delivery. 6 West Colony Place Durham, NC 27705 USA HAZARDOUS JELLYFISH PHONE: +1-919-684-2948 Of all the cnidarians, jellyfish cause the most MARINE LIFE: DAN EMERGENCY HOTLINE: +1-919-684-9111 frequent and severe human injuries. These result LEARN MORE AT DAN.ORG/HEALTH STINGS from direct contact with tentacles, and though painful, are not typically life threatening. PORTUGUESE MAN-OF-WAR Portuguese man-of-wars are free-floating cnidarians characterized by blue gas-filled bladders and long tentacles that drift on the ocean’s surface. Contact with a man-of-war’s Part #: 013-1040 Rev. 7.27.15 tentacles can cause significant pain and systemic symptoms. Their tentacles contain cnidocytes that deliver a potent proteic neurotoxin. Despite its resemblance to jellyfish, Portuguese man-of-war are more closely related to fire coral than to true jellyfish. HYDROIDS Although hydroids look like plants, these feathery cnidarians are actually a colony of small zooids that work together as a functioning animal. Like all cnidarians, these animals are armed with stinging cnidocytes. Hydroids, Portuguese man-of-war and fire coral belong to the same family, and contact with them can cause very similar reactions. Granted, their smaller contact area usually results in more localized and less dramatic reactions. FIRE CORAL Fire coral are colonial marine cnidarians that cause a mild to moderate burning reaction when touched.
[Show full text]
R E S E a R C H / M a N a G E M E N T Aquatic and Terrestrial Flatworm (Platyhelminthes, Turbellaria) and Ribbon Worm (Nemertea)
RESEARCH/MANAGEMENT FINDINGSFINDINGS “Put a piece of raw meat into a small stream or spring and after a few hours you may find it covered with hundreds of black worms... When not attracted into the open by food, they live inconspicuously under stones and on vegetation.” – BUCHSBAUM, et al. 1987 Aquatic and Terrestrial Flatworm (Platyhelminthes, Turbellaria) and Ribbon Worm (Nemertea) Records from Wisconsin Dreux J. Watermolen D WATERMOLEN Bureau of Integrated Science Services INTRODUCTION The phylum Platyhelminthes encompasses three distinct Nemerteans resemble turbellarians and possess many groups of flatworms: the entirely parasitic tapeworms flatworm features1. About 900 (mostly marine) species (Cestoidea) and flukes (Trematoda) and the free-living and comprise this phylum, which is represented in North commensal turbellarians (Turbellaria). Aquatic turbellari- American freshwaters by three species of benthic, preda- ans occur commonly in freshwater habitats, often in tory worms measuring 10-40 mm in length (Kolasa 2001). exceedingly large numbers and rather high densities. Their These ribbon worms occur in both lakes and streams. ecology and systematics, however, have been less studied Although flatworms show up commonly in invertebrate than those of many other common aquatic invertebrates samples, few biologists have studied the Wisconsin fauna. (Kolasa 2001). Terrestrial turbellarians inhabit soil and Published records for turbellarians and ribbon worms in leaf litter and can be found resting under stones, logs, and the state remain limited, with most being recorded under refuse. Like their freshwater relatives, terrestrial species generic rubric such as “flatworms,” “planarians,” or “other suffer from a lack of scientific attention. worms.” Surprisingly few Wisconsin specimens can be Most texts divide turbellarians into microturbellarians found in museum collections and a specialist has yet to (those generally < 1 mm in length) and macroturbellari- examine those that are available.
[Show full text]
Worm Comparison Chart Colwyn Sleep
Worm Comparison Chart Colwyn Sleep Platyhelminthes Nematoda Annelids Flatworms Roundworms Segmented worms Classifications Class Turbellaria: aka “Aschelminthes” Class Polychaeta Predators, scavengers, ¨many bristles¨. -heterotrophic -free-living flatworm Class Oligochaeta -incomplete gut, no includes earthworms. suckers or hooks. Class Hirudinea Class Trematoda: includes leeches. “parasitic worms” -incomplete gut, suckers, outer cuticle. Class Cestodae: “Parasitic worms” -no gut, suckers and hooks on a scolex -body consists of repeating sections called “proglottids.” Body symmetry and -bilaterally symmetrical. -pseudocoelom -bilaterally symmetrical. characteristics -3 layers of tissues with -body cavity partially -three germ layers organs and organelles. lined with mesoderm. -tube-within-a-tube body -no internal cavity. -tube within a tube body plan, and organs. -nervous system of plan -true coelom and longitudinal fibres rather -complete digestive segmentation. than a net. system -body cavity entirely -Reproduction mostly -unsegmented. lined with mesoderm. sexual as -bilateral symmetry. -the coelom is divided hermaphrodites. -cylindrical shape. into separate -mostly feed on animals -three germ layers. compartments by and other smaller life partitions. These septa forms. enable different -Some species occur in compartments to all major habitats, contract or expand including many as independently. parasites of other animals. -cephalization -body cavity filled with mesoderm. Worm Comparison Chart Colwyn Sleep environment (ie. Class Turbellaria: -live in nearly every Class Polychaeta aquatic, terrestrial) Live in the ocean. Some habitat including soil, -some live in tubes that live in fresh water. salt flats, aquatic may be made of sediments, polar calcium, silica (sand) or Trematoda + Cestoda regions, and the tropics protein Parasitic worms that live -don’t like dry places in the liver, lung, heart, Class Oligochaeta or intestine -live in soil and freshwater, some types are found in the ocean Class Hirudinea Aquatic, mostly freshwater, some marine varieties.
[Show full text]
Cnidarians Are Some of the Most Conspicuous and Colorful Tidepool Animals, Yet They Are Often Overlooked and Unappreciated
Page 1 of 1 Biology 122L – Invertebrate zoology lab Cnidarian diversity lab guide Author: Allison J. Gong Figure source: Brusca and Brusca, 2003. Invertebrates, second edition. Sinauer Associates, Inc. INTRODUCTION Cnidarians are some of the most conspicuous and colorful tidepool animals, yet they are often overlooked and unappreciated. To the untrained eye their radial symmetry makes cnidarians seem more plantlike than animallike, and the colonial forms of hydroids often have a "bushy" appearance that reinforces that mistaken first impression. However, cnidarians are indeed animals, and a closer examination of their bodies and behaviors will prove it to you. The generalized body plan of a cnidarian consists of an oral disc surrounded by a ring (or rings) of long tentacles, atop a column that contains the two-way gut, or coelenteron. This body plan can occur in either of two forms: a polyp, in which the column is attached to a hard surface with the oral disc and tentacles facing into the water; and a medusa, in which the column is (usually) unattached and the entire organism is surrounded by water. In the medusa phase the column is flattened and generally rounded to form the bell of the pelagic medusa. Cnidarian tentacles are armed with cnidocytes, cells containing the stinging capsules, or cnidae, that give the phylum its name. Cnidae are produced only by Page 2 of 2 cnidarians, although they can occasionally be found in the cerata of nudibranch molluscs that feed on cnidarians: through a process that is not understood, some nudibranchs are able to ingest cnidae from their prey and sequester them, unfired, in their cerata for defense against their own predators.
[Show full text]
The Comparative Embryology of Sponges Alexander V
The Comparative Embryology of Sponges Alexander V. Ereskovsky The Comparative Embryology of Sponges Alexander V. Ereskovsky Department of Embryology Biological Faculty Saint-Petersburg State University Saint-Petersburg Russia [email protected] Originally published in Russian by Saint-Petersburg University Press ISBN 978-90-481-8574-0 e-ISBN 978-90-481-8575-7 DOI 10.1007/978-90-481-8575-7 Springer Dordrecht Heidelberg London New York Library of Congress Control Number: 2010922450 © Springer Science+Business Media B.V. 2010 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Preface It is generally assumed that sponges (phylum Porifera) are the most basal metazoans (Kobayashi et al. 1993; Li et al. 1998; Mehl et al. 1998; Kim et al. 1999; Philippe et al. 2009). In this connection sponges are of a great interest for EvoDevo biolo- gists. None of the problems of early evolution of multicellular animals and recon- struction of a natural system of their main phylogenetic clades can be discussed without considering the sponges. These animals possess the extremely low level of tissues organization, and demonstrate extremely low level of processes of gameto- genesis, embryogenesis, and metamorphosis. They show also various ways of advancement of these basic mechanisms that allow us to understand processes of establishment of the latter in the early Metazoan evolution.
[Show full text]
Predatory Drill Holes in Paleocene Ostracods from Argentina and Methods to Infer Predation Intensit
[Palaeontology, 2019, pp. 1–26] A SMALL YET OCCASIONAL MEAL: PREDATORY DRILL HOLES IN PALEOCENE OSTRACODS FROM ARGENTINA AND METHODS TO INFER PREDATION INTENSITY by JORGE VILLEGAS-MARTIN1 ,DAIANECEOLIN2 , GERSON FAUTH1,2 and ADIEL€ A. KLOMPMAKER3 1Graduate Program in Geology, Universidade do Vale do Rio dos Sinos-UNISINOS, Av. Unisinos 950, 93022-000, S~ao Leopoldo, Rio Grande do Sul Brazil; [email protected], [email protected] 2Instituto Tecnologico de Micropaleontologia – itt Fossil, Universidade do Vale do Rio dos Sinos-UNISINOS, Av. Unisinos, 950, 93022-000, S~ao Leopoldo, Rio Grande do Sul Brazil; [email protected] 3Department of Integrative Biology & Museum of Paleontology, University of California, Berkeley, 1005 Valley Life Sciences Building #3140, Berkeley, CA 94720, USA; [email protected] Typescript received 6 May 2018; accepted in revised form 14 December 2018 Abstract: Ostracods are common yet understudied prey in ostracods. The cylindrical (Oichnus simplex) and parabolic item in the fossil record. We document drill holes in Pale- (O. paraboloides) drill holes from Argentina may have been ocene (Danian) ostracods from central Argentina using 9025 caused primarily by naticid and possibly muricid gastropods. specimens representing 66 species. While the percentage of Two oval drill holes (O. ovalis) are morphologically similar drilled specimens at assemblage-level is only 2.3%, consider- to octopod drill holes, but their small size, the fact that able variation exists within species (0.3–25%), suggesting extant octopods are not known to drill ostracods and the prey preference by the drillers. This preference is not deter- absence of such holes in co-occurring gastropods, preclude mined by abundance because no signiﬁcant correlation is ascription to a predator clade.
[Show full text]