DOCSLIB.ORG

Reproduction and Larval Development of the New Zealand Scallop, Pecten Novaezelandiae

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Reproduction and Larval Development of the New Zealand Scallop, Pecten Novaezelandiae Reproduction and larval development of the New Zealand scallop, Pecten novaezelandiae. Neil E. de Jong A thesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Science (MSc) 2013 School of Applied Science Table of Contents TABLE OF CONTENTS ...................................................................................... I TABLE OF FIGURES ....................................................................................... IV TABLE OF TABLES ......................................................................................... VI ATTESTATION OF AUTHORSHIP ................................................................. VII ACKNOWLEDGMENTS ................................................................................. VIII ABSTRACT ....................................................................................................... X 1 CHAPTER ONE: INTRODUCTION AND LITERATURE REVIEW .............. 1 1.1 Scallop Biology and Ecology ........................................................................................ 2 1.1.1 Diet ............................................................................................................................... 4 1.2 Fisheries and Aquaculture ............................................................................................ 5 1.2.1 Scallop Enhancement .................................................................................................. 8 1.2.2 Hatcheries .................................................................................................................. 10 1.3 Aims of this thesis ....................................................................................................... 11 2 CHAPTER TWO: BROODSTOCK CONDITIONING OF SCALLOPS. ..... 12 2.1 Introduction .................................................................................................................. 13 2.1.1 Biology ....................................................................................................................... 13 2.2 Broodstock conditioning............................................................................................. 14 2.2.1 Measures of gonad condition .................................................................................... 14 2.2.2 Colour ........................................................................................................................ 15 2.2.3 Spawning and post spawning .................................................................................... 15 2.2.4 Photoperiod................................................................................................................ 16 2.2.5 Temperature .............................................................................................................. 17 2.2.6 Diet ............................................................................................................................. 17 2.3 Aim ................................................................................................................................. 18 i 2.4 Methods and Materials ................................................................................................ 18 2.4.1 Animal collections ...................................................................................................... 18 2.4.2 Feeding experiment ................................................................................................... 18 2.4.3 Feeding rations .......................................................................................................... 21 2.4.4 Weight measurements ............................................................................................... 21 2.4.5 Gonad colour analysis ............................................................................................... 22 2.4.6 Visual grading index .................................................................................................. 23 2.4.7 Histological analyses ................................................................................................. 25 2.4.8 Acini and egg analysis ............................................................................................... 26 2.4.9 Statistics ..................................................................................................................... 28 2.5 Results .......................................................................................................................... 29 2.5.1 Feeding rations .......................................................................................................... 29 2.5.2 Mortality ..................................................................................................................... 29 2.5.3 Total tissue wet weight .............................................................................................. 29 2.5.4 Net tissue dry weight ................................................................................................. 30 2.5.5 Gonad wet weight ...................................................................................................... 32 2.5.6 Gonadalsomatic index ............................................................................................... 33 2.5.7 Colour ........................................................................................................................ 34 2.5.8 Male gonad colour ..................................................................................................... 35 2.5.9 Female gonad colour ................................................................................................. 36 2.5.10 Visual gonad index ................................................................................................ 37 2.5.11 Histological gonad index ....................................................................................... 38 2.5.12 Acini area ............................................................................................................... 40 2.5.13 Egg area ................................................................................................................ 41 2.5.14 Spawning ............................................................................................................... 42 2.6 Discussion .................................................................................................................... 44 2.6.1 Weight analyses ........................................................................................................ 44 2.6.2 Gonad development .................................................................................................. 44 2.6.3 Histological assessment ............................................................................................ 46 3 CHAPTER 3: TO CHARACTERISE LARVAL DEVELOPMENT (MORPHOLOGICAL, PHYSIOLOGICAL CHARACTERISTICS) OF THE NEW ZEALAND SCALLOP PECTEN NOVAEZELANDIAE FROM D-LARVAE TO PEDIVELIGER .................................................................................................. 48 3.1 Introduction .................................................................................................................. 49 3.1.1 Cultivation systems .................................................................................................... 50 3.1.2 Lifecycle ..................................................................................................................... 51 3.1.3 Spawning ................................................................................................................... 53 3.1.4 Larvae rearing ............................................................................................................ 54 ii 3.1.5 Larval feeding ............................................................................................................ 55 3.2 Aim ................................................................................................................................. 55 3.3 Methods and Materials ................................................................................................ 56 3.3.1 Broodstock ................................................................................................................. 56 3.3.2 Spawning procedure .................................................................................................. 57 3.3.3 Larval rearing and sampling ...................................................................................... 57 3.3.4 Light microscopy ........................................................................................................ 59 3.3.5 Scanning Electron Microscopy .................................................................................. 60 3.3.6 Sample analyses ....................................................................................................... 60 3.4 Results .......................................................................................................................... 61 3.4.1 Growth rates .............................................................................................................. 62 3.4.2 Clearance rates ......................................................................................................... 63 3.5 Embryogenesis ............................................................................................................ 64 3.5.1 Sperm .......................................................................................................................
Load more

Recommended publications
  • The Milkfish Broodstock-Hatchery Research and Development Program and Industry: a Policy Study
    A Service of Leibniz-Informationszentrum econstor Wirtschaft Leibniz Information Centre Make Your Publications Visible. zbw for Economics Israel, Danilo C. Working Paper The Milkfish Broodstock-Hatchery Research and Development Program and Industry: A Policy Study PIDS Discussion Paper Series, No. 2000-05 Provided in Cooperation with: Philippine Institute for Development Studies (PIDS), Philippines Suggested Citation: Israel, Danilo C. (2000) : The Milkfish Broodstock-Hatchery Research and Development Program and Industry: A Policy Study, PIDS Discussion Paper Series, No. 2000-05, Philippine Institute for Development Studies (PIDS), Makati City This Version is available at: http://hdl.handle.net/10419/127711 Standard-Nutzungsbedingungen: Terms of use: Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Documents in EconStor may be saved and copied for your Zwecken und zum Privatgebrauch gespeichert und kopiert werden. personal and scholarly purposes. Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle You are not to copy documents for public or commercial Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich purposes, to exhibit the documents publicly, to make them machen, vertreiben oder anderweitig nutzen. publicly available on the internet, or to distribute or otherwise use the documents in public. Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, If the documents have been made available under an Open gelten abweichend von diesen Nutzungsbedingungen die in der dort Content Licence (especially Creative Commons Licences), you genannten Lizenz gewährten Nutzungsrechte. may exercise further usage rights as specified in the indicated licence. www.econstor.eu Philippine Institute for Development Studies The Milkfish Broodstock-Hatchery Research and Development Program and Industry: A Policy Study Danilo C.
    [Show full text]
  • North America Broodstock Expanded Info
    Shrimp Is it what you think? Occasionally, a remarkable development takes place that redefines what’s possible for humanity. This slide deck defines this remarkable development, highlighting the opportunity that's sure to place stakeholders at the forefront of a market shift. To Appreciate the Magnitude of our extraordinary development, we must first paint the picture of an industry that's responsible for producing a food product that’s prized in every corner of the globe, regardless of socioeconomic standing, religious belief, or geographical location. We’ll look at the good, bad, and ugly, as it is today, and show you how the significance of our story stands to change everything. The Good The United States Loves Shrimp Consumptive shrimp is one of the most sought-after foods in the world. Americans alone consume more than one billion pounds of shrimp annually, making this by far the most popular seafood for consumption in the United States. According to the World Wildlife Federation, "Shrimp is the most valuable traded marine product in the world today. In 2005, farmed shrimp was a $10.6 Billion industry.” Today, the global shrimp farming industry has grown by nearly 325% in 15 years to about $45 Billion. The Bad America Doesn’t Produce Enough Up to and until now, the United States had no method for producing enough shrimp to satisfy the appetite of the American Consumer. Shrimp farms in Southeast Asia and Central America, plagued by disease and contamination, deliver frozen, 90% of the shrimp Americans eat. More Bad News Destroyed Ecosystems Climate Change Private Asia and Central America shrimp Imported, farmed shrimp can be ten farms utilize destructive procedures that times worse for the climate than beef.
    [Show full text]
  • Diseases Affecting Finfish
    Diseases Affecting Finfish Legislation Ireland's Exotic / Disease Name Acronym Health Susceptible Species Vector Species Non-Exotic Listed National Status Disease Measures Bighead carp (Aristichthys nobilis), goldfish (Carassius auratus), crucian carp (C. carassius), Epizootic Declared Rainbow trout (Oncorhynchus mykiss), redfin common carp and koi carp (Cyprinus carpio), silver carp (Hypophtalmichthys molitrix), Haematopoietic EHN Exotic * Disease-Free perch (Percha fluviatilis) Chub (Leuciscus spp), Roach (Rutilus rutilus), Rudd (Scardinius erythrophthalmus), tench Necrosis (Tinca tinca) Beluga (Huso huso), Danube sturgeon (Acipenser gueldenstaedtii), Sterlet sturgeon (Acipenser ruthenus), Starry sturgeon (Acipenser stellatus), Sturgeon (Acipenser sturio), Siberian Sturgeon (Acipenser Baerii), Bighead carp (Aristichthys nobilis), goldfish (Carassius auratus), Crucian carp (C. carassius), common carp and koi carp (Cyprinus carpio), silver carp (Hypophtalmichthys molitrix), Chub (Leuciscus spp), Roach (Rutilus rutilus), Rudd (Scardinius erythrophthalmus), tench (Tinca tinca) Herring (Cupea spp.), whitefish (Coregonus sp.), North African catfish (Clarias gariepinus), Northern pike (Esox lucius) Catfish (Ictalurus pike (Esox Lucius), haddock (Gadus aeglefinus), spp.), Black bullhead (Ameiurus melas), Channel catfish (Ictalurus punctatus), Pangas Pacific cod (G. macrocephalus), Atlantic cod (G. catfish (Pangasius pangasius), Pike perch (Sander lucioperca), Wels catfish (Silurus glanis) morhua), Pacific salmon (Onchorhynchus spp.), Viral
    [Show full text]
  • Nutrition, Feeds and Feed Technology for Mariculture in India Vijayagopal P
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CMFRI Digital Repository Course Manual Nutrition, Feeds and Feed Technology for Mariculture in India Vijayagopal P. [email protected] Central Marine Fisheries Research Institute, Kochi - 18 Mariculture of finfish on a commercial scale is non-existent in India. CMFRI, RGCA of MPEDA, CIBA are the Institutions promoting finfish mariculture with demonstrated seed production capabilities of Asian seabass (Lates calcarifer), cobia (Rachycentron canadum) and silver pompano (Trachynotus blochii). Seed production is not sufficient enough togo in for commercial scale investment. Requisite private investment has not flown into this segment of aquabusiness and Public Private Partnerships (PPP) are yet to take off. The scenario being this in the case of one (seed) of the two major inputs in this food production system, feeds and feeding, which is the other is the subject of elaboration here. Quality marine fish like king seer, pomfrets and tuna retails at more than Rs.400/- per kg in domestic markets. In metro cities it Rs.1000/- per kg is not surprising. With this purchasing power in the domestic market, most of the farmed marine fish is sold to such a clientele which is ever increasing in India. Therefore, without any assurance of a sustainable supply of such fish from capture fisheries, there is no doubt that we have to farm quality marine fish. With as deficit in seed supply at present, let us examine nutrition, feeds and feed technology required for this farming system in India. Farming sites, technologies of cage fabrication and launch, day-to-day management, social issues, policy, economics and health management, harvest and marketing, development of value chains, traceability and certification are all equally important and may or may not be dealt with in this training programme.
    [Show full text]
  • AEBR 114 Review of Factors Affecting the Abundance of Toheroa Paphies
    Review of factors affecting the abundance of toheroa (Paphies ventricosa) New Zealand Aquatic Environment and Biodiversity Report No. 114 J.R. Williams, C. Sim-Smith, C. Paterson. ISSN 1179-6480 (online) ISBN 978-0-478-41468-4 (online) June 2013 Requests for further copies should be directed to: Publications Logistics Officer Ministry for Primary Industries PO Box 2526 WELLINGTON 6140 Email: [email protected] Telephone: 0800 00 83 33 Facsimile: 04-894 0300 This publication is also available on the Ministry for Primary Industries websites at: http://www.mpi.govt.nz/news-resources/publications.aspx http://fs.fish.govt.nz go to Document library/Research reports © Crown Copyright - Ministry for Primary Industries TABLE OF CONTENTS EXECUTIVE SUMMARY ....................................................................................................... 1 1. INTRODUCTION ............................................................................................................ 2 2. METHODS ....................................................................................................................... 3 3. TIME SERIES OF ABUNDANCE .................................................................................. 3 3.1 Northland region beaches .......................................................................................... 3 3.2 Wellington region beaches ........................................................................................ 4 3.3 Southland region beaches .........................................................................................
    [Show full text]
  • Carotenoid Extraction from the Gonad of the Scallop Nodipecten Nodosus
    Carotenoid extraction from the gonad of the scallop Nodipecten nodosus (Linnaeus, 1758) (Bivalvia: Pectinidae) Suhnel, S.a*, Lagreze, F.a, Ferreira, JF.a Campestrini, LH.b and Maraschin, M.b* aLaboratório de Moluscos Marinhos, Universidade Federal de Santa Catarina – UFSC Servidão dos Coroas, s/n, Barra da Lagoa, CEP 88061-600, Florianópolis, SC, Brazil bLaboratório de Morfogênese e Bioquímica Vegetal, Universidade Federal de Santa Catarina – UFSC Rod. Admar Gonzaga, 1346, Itacorubi, CEP 88040-900, Florianópolis, SC, Brazil *e-mail: [email protected], [email protected] Received November 14, 2007 – Accepted March 12, 2008 – Distributed February 28, 2009 (With 2 figures) Abstract In marine bivalve mollusks, unsaturated molecules called carotenoids are present in the natural diet and play an important role in different biological process, especially in reproduction. In order to gain more insights into these compounds in Nodipecten nodosus it was necessary to develop a suitable protocol for extraction of carotenoids from the gonads. Female gonads of cultured scallops (75 mm length) were lyophilized and macerated in liquid N2. To verify the effect of composition in organosolvents on the extracting solutions, two organic solvents were tested: acetone and hexane (Ac = O:Hex) at four ratios, 1:1, 1:3, 1:5, and 2:3, in four static extraction times: 0, 5, 10, and 15 minutes. Total carotenoids and astaxanthin contents were determined in the crude extracts by UV-visible spectrophotometry and high performance liquid chromatography (HPLC), respectively. Triplicate aliquots of 50 mg were used for each treatment. The results indicated that the best single extraction (0.312 ± 0.016 µg carotenoids/mg) was attained with Ac = O: Hex 1:3, for 15 minutes.
    [Show full text]
  • Diversity of Malacofauna from the Paleru and Moosy Backwaters Of
    Journal of Entomology and Zoology Studies 2017; 5(4): 881-887 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2017; 5(4): 881-887 Diversity of Malacofauna from the Paleru and © 2017 JEZS Moosy backwaters of Prakasam district, Received: 22-05-2017 Accepted: 23-06-2017 Andhra Pradesh, India Darwin Ch. Department of Zoology and Aquaculture, Acharya Darwin Ch. and P Padmavathi Nagarjuna University Nagarjuna Nagar, Abstract Andhra Pradesh, India Among the various groups represented in the macrobenthic fauna of the Bay of Bengal at Prakasam P Padmavathi district, Andhra Pradesh, India, molluscs were the dominant group. Molluscs were exploited for Department of Zoology and industrial, edible and ornamental purposes and their extensive use has been reported way back from time Aquaculture, Acharya immemorial. Hence the present study was focused to investigate the diversity of Molluscan fauna along Nagarjuna University the Paleru and Moosy backwaters of Prakasam district during 2016-17 as these backwaters are not so far Nagarjuna Nagar, explored for malacofauna. A total of 23 species of molluscs (16 species of gastropods belonging to 12 Andhra Pradesh, India families and 7 species of bivalves representing 5 families) have been reported in the present study. Among these, gastropods such as Umbonium vestiarium, Telescopium telescopium and Pirenella cingulata, and bivalves like Crassostrea madrasensis and Meretrix meretrix are found to be the most dominant species in these backwaters. Keywords: Malacofauna, diversity, gastropods, bivalves, backwaters 1. Introduction Molluscans are the second largest phylum next to Arthropoda with estimates of 80,000- 100,000 described species [1]. These animals are soft bodied and are extremely diversified in shape and colour.
    [Show full text]
  • Physiological Effects and Biotransformation of Paralytic
    PHYSIOLOGICAL EFFECTS AND BIOTRANSFORMATION OF PARALYTIC SHELLFISH TOXINS IN NEW ZEALAND MARINE BIVALVES ______________________________________________________________ A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy in Environmental Sciences in the University of Canterbury by Andrea M. Contreras 2010 Abstract Although there are no authenticated records of human illness due to PSP in New Zealand, nationwide phytoplankton and shellfish toxicity monitoring programmes have revealed that the incidence of PSP contamination and the occurrence of the toxic Alexandrium species are more common than previously realised (Mackenzie et al., 2004). A full understanding of the mechanism of uptake, accumulation and toxin dynamics of bivalves feeding on toxic algae is fundamental for improving future regulations in the shellfish toxicity monitoring program across the country. This thesis examines the effects of toxic dinoflagellates and PSP toxins on the physiology and behaviour of bivalve molluscs. This focus arose because these aspects have not been widely studied before in New Zealand. The basic hypothesis tested was that bivalve molluscs differ in their ability to metabolise PSP toxins produced by Alexandrium tamarense and are able to transform toxins and may have special mechanisms to avoid toxin uptake. To test this hypothesis, different physiological/behavioural experiments and quantification of PSP toxins in bivalves tissues were carried out on mussels ( Perna canaliculus ), clams ( Paphies donacina and Dosinia anus ), scallops ( Pecten novaezelandiae ) and oysters ( Ostrea chilensis ) from the South Island of New Zealand. Measurements of clearance rate were used to test the sensitivity of the bivalves to PSP toxins. Other studies that involved intoxication and detoxification periods were carried out on three species of bivalves ( P.
    [Show full text]
  • Aquaculture and Marketing of the Florida Bay Scallop in Crystal River, Florida
    Aquaculture and marketing of the Florida Bay Scallop in Crystal River, Florida Item Type monograph Authors Blake, Norman J.; Adams, Charles; Degner, Robert; Sweat, Don; Moss, Susan D.; Sturmer, Leslie Publisher Florida Sea Grant College Program Download date 10/10/2021 07:29:03 Link to Item http://hdl.handle.net/1834/20351 FLORIDA SEA GRANT COLLEGE PROGRAM FLSGP-T-00-002 C2 R/LRcAc20 Aquaculture and Marketing of the Florida Bay Scallop in Crystal River, Florida by Norman J. Blake, Charles Adams, Robert Degner, and Don Sweat with special reports on Marketing Analysis by Susan D. Moss, Robert Degner, and Charles Adams and Economic Analysis by Charles Adams and Leslie Sturmer TP-106 October 2000 l_ UNIVERSITY OF ~.·JFLORID·A Sm~ "..:',..!.!!!.;/ ~ EXTENSION Florida Institute of Food and Agricultural Sciences This technical paper was supported by the National Sea Grant College Program of the U.S. Department of Commerce's National Oceanicand Atmosheric Administration under NOAA Grant # NA 76RG-0120. The views expressed herein do not necessarily reflect the views of any of these organizations. Aquaculture and Marketing ofthe ~lorida Bay Scallop in Crystal River, Florida By Norman 1. Blake, Department ofMarine Sciences, University ofSouth Florida, St. Petersburg Charles Adams, Food & Resource Economics, University ofFlorida, Gainesville Robert Degner, Florida Agricultural Market Research Center, University ofFlorida, Gainesville Don Sweat Florida Sea Grant Marine Agent University of Florida St. Petersburg Submitted to·Florida Sea Grant Final
    [Show full text]
  • Overcoming Barriers in the Scallop Aquaculture Industry a First Nations Perspective Spring 2013
    Fall 08 0 OVERCOMING BARRIERS IN THE SCALLOP AQUACULTURE INDUSTRY A FIRST NATIONS PERSPECTIVE SPRING 2013 Photo Credit: Jeff Svanhill JEFF SVANHILL ISIS, Sauder School of Business, University of British Columbia Published in partnership with the Nanwakolas Council ISIS | Overcoming Barriers in the Scallop Aquaculture Industry | Jeff Svanhill | 1 TABLE OF CONTENTS ACKNOWLEDGEMENTS 3 EXECUTIVE SUMMARY 4 INTRODUCTION 5 Layout of this Report 5 1.0 WHY SCALLOPS? 6 2.0 COLLABORATION 8 2.1 Collaboration 8 2.1.1 Why Collaborate? 8 2.1.2 Notes on Collaboration 9 3.0 FUNDING OPTIONS 10 3.1 Funding and Financing options 10 3.1.1 Funding 10 3.1.2 Financing 11 4.0 SCALLOP SEED SUPPLY OPTIONS 12 4.1 Scallop Seed Procurement Overview 12 4.1.1 Domestic Procurement 12 4.1.2 International Procurement 13 4.2 Local Supply Options 14 4.2.1 Island Scallops 14 4.2.2 Wenlian Aquaculture Company 15 4.3 Future Supply Options 15 4.3.1 Coastal Shellfish Corporation 15 ISIS | Overcoming Barriers in the Scallop Aquaculture Industry | Jeff Svanhill | 2 LIST OF FIGURES FIGURE 1 – MAJOR SHELLFISH SPECIES HARVESTED IN BRITISH COLUMBIA (2011) 6 FIGURE 2 – CHANGE IN ATMOSPHERIC CO2, SEAWATER PCO2 AND SEAWATER PH OVER TIME IN THE NORTH PACIFIC 7 FIGURE 3 – FUNDING FOR SKILLS DEVELOPMENT 10 FIGURE 4 – FUNDING FOR BUSINESS PLANNING 10 FIGURE 9 – VANCITY FINANCING PROGRAMS 11 FIGURE 10 – LOCATION OF SCALLOP AQUACULTURE INDUSTRY IN CHINA 13 ISIS | Overcoming Barriers in the Scallop Aquaculture Industry | Jeff Svanhill | 3 ACKNOWLEDGEMENTS This report was prepared by Jeff Svanhill at the ISIS Research Centre, Sauder School of Business, University of British Columbia.
    [Show full text]
  • Cobia and Pompano Handbook
    CMFRI Booklet Series No. 19/2019 2019 CMFRI Booklet Series No. 19/2019 \\_Ii--/}// \<�\\:I,. t.;w1 Central Marine Fisheries Research Institute !1�= Practical Hand Book on CMFR Seed Production of Cobia and Silver Pompano Prepared by Dr.A.K.AbdulNazar Dr. R. layakumar Dr. G. Tamilmani Dr. M. Sakthivel Dr. P. Ramesh Kumar Dr.K.K.Anikuttan M.Sankar Mandapam Regional Centre of CMFRI Mandapam Camp - 623 520 Tamil Nadu, India 2019 © 2019 ICAR –Central Marine Fisheries Research Institute CMFRI Booklet Series No. 19/2019 Published by Dr. A. Gopalakrishnan Director !CAR-Central Marine Fisheries Research Institute Kochi - 682 018 Typeset and Printed by Rehana Offset Printers, Srivilliputtur - 626 125 Phone : 04563-260383, E-mail : [email protected] PREFACE Mariculture – the farming and husbandry of marine plants and animals of commercial importance, is an untapped sector of sea food production in India. Mariculture has been contributing substantially to the global fish production in recent years. It accounted for about 29.2 per cent of world aquaculture production by value. It is a fact that India is still in infancy in mariculture production in the global scenario. Since mariculture is the only hope for increasing seafood production in the coming years, the research and development in this sector is of paramount importance. In fact, such thrust was not given in India and hence, it was felt necessary to develop viable seed production and farming technologies to develop mariculture. The R&D efforts in this direction yielded commendable results within a few years and Mandapam Regional Centre of ICAR CMFRI succeeded in captive breeding and seed production of two high value marine fishes namely, Cobia, Rachycentron canadum and Silver pompano, Trachinotus blochii for the first time in the country.
    [Show full text]
  • Early Ontogeny of Jurassic Bakevelliids and Their Bearing on Bivalve Evolution
    Early ontogeny of Jurassic bakevelliids and their bearing on bivalve evolution NIKOLAUS MALCHUS Malchus, N. 2004. Early ontogeny of Jurassic bakevelliids and their bearing on bivalve evolution. Acta Palaeontologica Polonica 49 (1): 85–110. Larval and earliest postlarval shells of Jurassic Bakevelliidae are described for the first time and some complementary data are given concerning larval shells of oysters and pinnids. Two new larval shell characters, a posterodorsal outlet and shell septum are described. The outlet is homologous to the posterodorsal notch of oysters and posterodorsal ridge of arcoids. It probably reflects the presence of the soft anatomical character post−anal tuft, which, among Pteriomorphia, was only known from oysters. A shell septum was so far only known from Cassianellidae, Lithiotidae, and the bakevelliid Kobayashites. A review of early ontogenetic shell characters strongly suggests a basal dichotomy within the Pterio− morphia separating taxa with opisthogyrate larval shells, such as most (or all?) Praecardioida, Pinnoida, Pterioida (Bakevelliidae, Cassianellidae, all living Pterioidea), and Ostreoida from all other groups. The Pinnidae appear to be closely related to the Pterioida, and the Bakevelliidae belong to the stem line of the Cassianellidae, Lithiotidae, Pterioidea, and Ostreoidea. The latter two superfamilies comprise a well constrained clade. These interpretations are con− sistent with recent phylogenetic hypotheses based on palaeontological and genetic (18S and 28S mtDNA) data. A more detailed phylogeny is hampered by the fact that many larval shell characters are rather ancient plesiomorphies. Key words: Bivalvia, Pteriomorphia, Bakevelliidae, larval shell, ontogeny, phylogeny. Nikolaus Malchus [[email protected]], Departamento de Geologia/Unitat Paleontologia, Universitat Autòno− ma Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Spain.
    [Show full text]