DOCSLIB.ORG

Cretaceous Actaeonellid Gastropods from the Western Hemisphere

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cretaceous Actaeonellid Gastropods from the Western Hemisphere Cretaceous Actaeonellid Gastropods from the Western Hemisphere GEOLOGICAL SURVEY PROFESSIONAL PAPEU 1304 Cretaceous Actaeonellid Gastropods from the Western Hemisphere By NORMAN F. SOHL and HEINZ A. KOLLMANN GEOLOGICAL SURVEY PROFESSIONAL PAPER 1304 A description of 28 species of actaeonellid gastropods, with a discussion of the evolution, life habits, ecology, and Cretaceous world distribution of the family UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1985 DEPARTMENT OF THE INTERIOR WILLIAM P. CLARK, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress Cataloging in Publication Data Sohl, Norman Frederick, 1924- Cretaceous actaeonellid gastropods from the Western Hemisphere. (Geological Survey professional paper ; 1304) Bibliography: p. Includes index. Supt. of Docs, no.: I 19.6:1304 1. Actaeonellidae. 2. Paleontology Cretaceous. 3. Paleontology America. I. Kollmann, Heinz A. II. Title. III. Series. QE809.A18S63 1984 564'.37 83-600250 For sale by the Distribution Branch, U.S. Geological Survey, 604 South Pickett Street, Alexandria, VA 22304 CONTENTS Page Abstract 1 Distribution and diversity - 9 Introduction 1 Evolution of the Actaeonellidae - 20 Acknowledgments - 2 Stratigraphic summary of Western Hemisphere actaeonellid Reflections of soft parts on the actaeonellid shell 2 occurrence - 22 Columellar retractor muscles 2 Early Cretaceous record - 24 Character of the mantle edge 2 Late Cretaceous record - 24 Musculature of the head-foot mass 4 Locality register 35 Exhalant area 4 Systematic paleontology - 46 ______________________________ 4 Catalogue of actaeonellid species- 74 Genera and species excluded from the Actaeonellidae 87 Substrate preference 6 References cited 90 Salinity tolerance 7 Index 97 Early ontogeny and dispersal potential of actaeonellids 9 ILLUSTRATIONS [Plates follow index] PLATE 1. Polished section of oriented rock surface from roadcut, Erath County, Tex. 2. Trochactaeon, Actaeonella 3-16. Trochactaeon 17. Actaeonella, Trochactaeon 18-23. Actaeonella Page FIGURE 1. Morphologic features of the actaeonellids 3 2. Postulated salinity ranges for various Cretaceous faunal assemblages in which actaeonellid gastropods occur 8 3-4. Histograms of 3. Species diversity of the subgenera of Trochactaeon during the Cretaceous 10 4. Actaeonella species diversity during the Cretaceous 10 5-9. Occurrence of Trochactaeon £) ^Duriiisr thG BsnT^mi&n ______ - ______________ ___________________________ _______ 11 6. During the Aptian and Albian 12 7. During the Cenomanian and early Turonian 13 8. During the late Turonian to Santonian 14 9. During the Campanian and Maastrichtian 15 10-13. Occurrence of Actaeonella 11. During the Cenomanian and early Turonian 17 12. During the late Turonian to Santonian 18 13. During the Campanian and Maastrichtian 19 14. Phylogeny of the Actaeonellidae as presented by three previous authors 2 1 15. Proposed phylogeny of the Actaeonellidae 23 16. Correlation of middle Cretaceous formations of Puerto Rico and Texas 25 17-18. Correlation of the Upper Cretaceous rocks of 17. Puerto Rico 26 18. Central and western Jamaica 27 19. Stratigraphic ranges of the Western Hemisphere actaeonellid gastropod species 28 m IV CONTENTS FIGURES 20-25. Index maps showing 20. Collection localities in Puerto Rico 29 21. Collection localities and occurrence of Cretaceous rocks in Jamaica 30 22. Collection localities and areas of Cretaceous outcrop in Cuba 31 23. Collection localities in Texas and New Mexico 32 24. Collection localities in Mexico and Guatemala 33 25. Collection localities in California 34 26-45. Scatter diagrams comparing height with width among selected specimens of 26. Trochactaeon (Trochactaeon) woodsi (Rennie) 49 27. Trochactaeon (Trochactaeon)packardi (Anderson) 52 28. Trochactaeon (Neocylindrites) cumminsi Stanton 53 29. Trochactaeon (Neocylindrites) nelsoni Sohl and Kollmann, n. sp. 55 30. Trochactaeon (Mexicotrochactaeon) conformis (Bose) 57 31. Trochactaeon (Mexicotrochactaeon) burckhardti(B6se) 58 32. Trochactaeon (Mexicotrochactaeon) wrighti Sohl and Kollmann, n. sp. 59 33. Trochactaeon (Mexicotrochactaeon)palmeri Sohl and Kollmann, n. sp. 60 34. Trochactaeon (Mexicotrochactaeon) granthamensis Sohl and Kollmann, n. sp. 61 35. Trochactaeon (Mexicotrochactaeon) rossi Sohl and Kollmann, n. sp. 62 36. Actaeonellapecosensis Stanton 65 37. Actaeonella delgadoi Choffat 66 38. Actaeonella browni Sohl and Kollmann, n. sp. 67 39. Actaeonella borneensis Nuttall and Leong - 68 40. Actaeonella duckettsensis Sohl and Kollmann, n. sp. 69 41. Actaeonella jicarensis Sohl and Kollmann, n. sp. 70 42. Actaeonella coquiensis Sohl and Kollmann, n. sp. 70 43. Actaeonella marchmontensis Sohl and Kollmann, n. sp. 71 44. Actaeonella briggsi Sohl and Kollmann, n. sp. 72 45. Actaeonella cubensis Sohl and Kollmann, n. sp. 73 CRETACEOUS ACTAEONELLID GASTROPODS FROM THE WESTERN HEMISPHERE By NORMAN F. SOHL and HEINZ A. KOLLMANN1 ABSTRACT species of Trochactaeon are described, seven of them new. In addi­ tion, three more species are distinguished but not formally proposed Actaeonellid gastropods constitute one family of the cephalaspidean because of insufficient material. Actaeonella is represented by 14 opisthobranch superfamily Acteonacea. During the Cretaceous they described species (nine new), and one species is distinguished but were one of the most common biotic elements in the shallow warm- unnamed because of inadequate information. water faunas of the Tethyan Realm. They were common associates of A final section of this report consists of a catalogue of the described the rudist framework ("reef) tracts that in the Western Hemisphere Cretaceous species of actaeonellids. This listing is the data base used ranged throughout the Mexico-Central America-Antillean-Gulf for the construction of the maps of distribution and the histograms of Coast region. Maps are presented showing the worldwide distribu­ diversity with time. tion of these gastropods during five time intervals of the Cretaceous Period. Their greatest latitudinal extent was during Albian to INTRODUCTION Cenomanian times; subsequently, they were restricted to narrowed Tethyan and marginal Tethyan areas. One paleolatitudinal anoma­ Knowledge of the Cretaceous molluscan faunas of the lous occurrence in Alaska may be related to current concepts of Western Hemisphere is very unequal with respect to suspect allocthonous terranes. Actaeonellids show a progressive increase in numbers of species geographic areas, biologic group, and stratigraphic in­ from their first appearance in the Barremian Stage to a high in the terval. For example, mollusks of the late Late Creta­ late Turonian to Santonian interval. Subsequently, their diversity ceous of the Coastal Plains of eastern North America declined during the Campanian and Maastrichtian, and, like their are quite well documented, whereas those of the Carib­ common associates the nerineid gastropods and rudist bivalves, they bean region to the immediate south are, overall, poorly became extinct at the end of the Cretaceous. Their record in the Western Hemisphere is at some variance with that of actaeonellids known. In the Caribbean region, only one molluscan in the rest of the world. During the latest Cretaceous, they main­ group, the rudist bivalves, is at all reasonably known. tained a high level of diversity in the Caribbean to Mexico region In general, knowledge of the Western Hemisphere and showed a tendency toward taxonomic provincialism. This latter faunas of the Cretaceous temperate marine seas is feature is demonstrated by the appearance in the Maastrichtian of much greater than that of faunas of the Tethyan species of Actaeonella having only two instead of three columellar plications and by the presence of an endemic subgenus Trochactaeon (warm-water tropical) biogeographic province. The (Mexicotrochactaeon) in rocks of Coniacian to Maastrichtian Age. present work is intended to give detailed information Evidence is presented to indicate that actaeonellids possessed two about the Actaeonellidae, one of the major molluscan distinct adult life habits. At postlarval metamorphosis, both groups distributed throughout the warm-water Tethyan Actaeonella and Trochactaeon were initially epifaunal. Subsequently, Actaeonella assumed an infaunal habit, whereas Trochactaeon re­ Realm. mained epifaunal to adulthood. In addition, studies of associated The Actaeonellidae constitute but one family of the biotic elements suggest that the two genera possessed different cephalaspidean opisthobranch superfamily Acteonacea. salinity tolerance; Trochactaeon (Trochactaeon) had the broader As here conceived, they were restricted to the Creta­ range of tolerance, ranging well into environments of low salinity. ceous Period. Their extinction at the end of the Creta­ Only two genera, Actaeonella and Trochactaeon, are recognized as ceous coincided with that of the rudist bivalves, present in the Western Hemisphere. Trochactaeon is subdivided as follows: the nominate subgenus, T. (Neocylindrites), T. (Sevanella), nerineid gastropods, and other major faunal associates and T. (Mexicotrochactaeon). Of these, only T. (Sevanella) lacks repre­ of the Tethyan warm-water biota. Although the ac­ sentation in this hemisphere. The earliest occurrences in the taeonellids were of low generic diversity, the almost Western Hemisphere of species of Actaeonella and Trochactaeon 200 species recorded in the catalogue section of this (Neocylindrites) are in rocks of Albian Age. The reason for their report show that though
Load more

Recommended publications
  • Stratigraphy, Paleontology and Correlation of Lower Cretaceous Exposures in Southeastern New Mexico Barry S
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/44 Stratigraphy, paleontology and correlation of lower Cretaceous exposures in southeastern New Mexico Barry S. Kues and Spencer G. Lucas, 1993, pp. 245-260 in: Carlsbad Region (New Mexico and West Texas), Love, D. W.; Hawley, J. W.; Kues, B. S.; Austin, G. S.; Lucas, S. G.; [eds.], New Mexico Geological Society 44th Annual Fall Field Conference Guidebook, 357 p. This is one of many related papers that were included in the 1993 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks.
    [Show full text]
  • Schützenkönig
    Bataillonsschießen 2015 Schützenkönig Rg Name Wert 1 Kirchmair Josef Hinterthiersee 158,0 2 Trainer Christian Hinterthiersee 577,0 3 Moser Andreas Brandenberg 611,0 4 Schachner Simone Wörgl 866,0 5 Thaler Sebastian Schwoich 1741,0 6 Hotter Roland Langkampfen 2107,0 7 Thaler Alois Schwoich 2108,0 8 Burgstaller Gregor 3000,0 9 Embacher Bernhard Langkampfen 3000,0 10 Hintner Patrik Brandenberg 3000,0 11 Hohlrieder Johann Wildschönau 3000,0 12 Jaworek Stanis Wörgl 3000,0 13 Lechner Maria Kundl 3000,0 14 Mairhofer Anton Landl 3000,0 15 Marksteiner Stefan Kramsach 3000,0 16 Ott Kilian Wildschönau 3000,0 17 Payr Stefan Schwoich 3000,0 18 Praschberger Thomas Niederndorf 3000,0 19 Sauermoser Georg Kundl 3000,0 20 Seisl Josef Wildschönau 3000,0 21 Thaler Georg Wildschönau 3000,0 22 Unterberger Anton Langkampfen 3000,0 23 Achrainer Martina Wörgl 4000,0 24 Ampferer Manuel Brandenberg 4000,0 25 Auer Josef Brandenberg 4000,0 26 Egger Hermann 4000,0 27 Eggersberger Daniel Kufstein 4000,0 28 Freithofer Florian Bad Häring 4000,0 29 Gföller Andreas Wildschönau 4000,0 30 Gföller Hannes Wildschönau 4000,0 31 Greiderer Karl Niederndorf 4000,0 32 Gruber Josef Breitenbach 4000,0 33 Gschwentner Harald Schwoich 4000,0 34 Gschwentner Martin Schwoich 4000,0 35 Gschwentner Walter Breitenbach 4000,0 36 Gwercher Michael Brandenberg 4000,0 37 Holzknecht Daniel Kramsach 4000,0 38 Juffinger Peter Hinterthiersee 4000,0 39 Kirchmair Franz Hinterthiersee 4000,0 40 Klemt Anna Bad Häring 4000,0 Wörgl, am 09.09.2015 Wettkampfdatum: 05.09.2015 Seite 1 Mit FinePrint gedruckt - bitte bei www.context-gmbh.de registrieren.
    [Show full text]
  • High Level Environmental Screening Study for Offshore Wind Farm Developments – Marine Habitats and Species Project
    High Level Environmental Screening Study for Offshore Wind Farm Developments – Marine Habitats and Species Project AEA Technology, Environment Contract: W/35/00632/00/00 For: The Department of Trade and Industry New & Renewable Energy Programme Report issued 30 August 2002 (Version with minor corrections 16 September 2002) Keith Hiscock, Harvey Tyler-Walters and Hugh Jones Reference: Hiscock, K., Tyler-Walters, H. & Jones, H. 2002. High Level Environmental Screening Study for Offshore Wind Farm Developments – Marine Habitats and Species Project. Report from the Marine Biological Association to The Department of Trade and Industry New & Renewable Energy Programme. (AEA Technology, Environment Contract: W/35/00632/00/00.) Correspondence: Dr. K. Hiscock, The Laboratory, Citadel Hill, Plymouth, PL1 2PB. [email protected] High level environmental screening study for offshore wind farm developments – marine habitats and species ii High level environmental screening study for offshore wind farm developments – marine habitats and species Title: High Level Environmental Screening Study for Offshore Wind Farm Developments – Marine Habitats and Species Project. Contract Report: W/35/00632/00/00. Client: Department of Trade and Industry (New & Renewable Energy Programme) Contract management: AEA Technology, Environment. Date of contract issue: 22/07/2002 Level of report issue: Final Confidentiality: Distribution at discretion of DTI before Consultation report published then no restriction. Distribution: Two copies and electronic file to DTI (Mr S. Payne, Offshore Renewables Planning). One copy to MBA library. Prepared by: Dr. K. Hiscock, Dr. H. Tyler-Walters & Hugh Jones Authorization: Project Director: Dr. Keith Hiscock Date: Signature: MBA Director: Prof. S. Hawkins Date: Signature: This report can be referred to as follows: Hiscock, K., Tyler-Walters, H.
    [Show full text]
  • Shell Classification – Using Family Plates
    Shell Classification USING FAMILY PLATES YEAR SEVEN STUDENTS Introduction In the following activity you and your class can use the same techniques as Queensland Museum The Queensland Museum Network has about scientists to classify organisms. 2.5 million biological specimens, and these items form the Biodiversity collections. Most specimens are from Activity: Identifying Queensland shells by family. Queensland’s terrestrial and marine provinces, but These 20 plates show common Queensland shells some are from adjacent Indo-Pacific regions. A smaller from 38 different families, and can be used for a range number of exotic species have also been acquired for of activities both in and outside the classroom. comparative purposes. The collection steadily grows Possible uses of this resource include: as our inventory of the region’s natural resources becomes more comprehensive. • students finding shells and identifying what family they belong to This collection helps scientists: • students determining what features shells in each • identify and name species family share • understand biodiversity in Australia and around • students comparing families to see how they differ. the world All shells shown on the following plates are from the • study evolution, connectivity and dispersal Queensland Museum Biodiversity Collection. throughout the Indo-Pacific • keep track of invasive and exotic species. Many of the scientists who work at the Museum specialise in taxonomy, the science of describing and naming species. In fact, Queensland Museum scientists
    [Show full text]
  • Possible Anti-Predation Properties of the Egg Masses of the Marine Gastropods Dialula Sandiegensis, Doris Montereyensis and Haminoea Virescens (Mollusca, Gastropoda)
    Possible anti-predation properties of the egg masses of the marine gastropods Dialula sandiegensis, Doris montereyensis and Haminoea virescens (Mollusca, Gastropoda) E. Sally Chang1,2 Friday Harbor Laboratories Marine Invertebrate Zoology Summer Term 2014 1Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250 2University of Kansas, Department of Ecology and Evolutionary Biology, Lawrence, KS 66044 Contact information: E. Sally Chang Dept. of Ecology and Evolutionary Biology University of Kansas 1200 Sunnyside Avenue Lawrence, KS 66044 [email protected] Keywords: gastropods, nudibranchs, Cephalaspidea, predation, toxins, feedimg, crustaceans Chang 1 Abstract Many marine mollucs deposit their eggs on the substrate encapsulated in distinctive masses, thereby leaving the egg case and embryos vulnerable to possible predators and pathogens. Although it is apparent that many marine gastropods possess chemical anti-predation mechanisms as an adult, it is not known from many species whether or not these compounds are widespread in the egg masses. This study aims to expand our knowledge of egg mass predation examining the feeding behavior of three species of crab when offered egg mass material from three gastropods local to the San Juan Islands. The study includes the dorid nudibranchs Diaulula sandiegensis and Doris montereyensis and the cephalospidean Haminoea virescens. The results illustrate a clear rejection of the egg masses by all three of the crab species tested, suggesting anti- predation mechanisms in the egg masses for all three species of gastropod. Introduction Eggs that are laid and then left by the parents are vulnerable to a variety of environmental stressors, both biotic and abiotic. A common, possibly protective strategy among marine invertebrates is to lay encapsulated aggregations of embryos in jelly masses (Pechenik 1978), where embryos live for all or part of their development.
    [Show full text]
  • DEEP SEA LEBANON RESULTS of the 2016 EXPEDITION EXPLORING SUBMARINE CANYONS Towards Deep-Sea Conservation in Lebanon Project
    DEEP SEA LEBANON RESULTS OF THE 2016 EXPEDITION EXPLORING SUBMARINE CANYONS Towards Deep-Sea Conservation in Lebanon Project March 2018 DEEP SEA LEBANON RESULTS OF THE 2016 EXPEDITION EXPLORING SUBMARINE CANYONS Towards Deep-Sea Conservation in Lebanon Project Citation: Aguilar, R., García, S., Perry, A.L., Alvarez, H., Blanco, J., Bitar, G. 2018. 2016 Deep-sea Lebanon Expedition: Exploring Submarine Canyons. Oceana, Madrid. 94 p. DOI: 10.31230/osf.io/34cb9 Based on an official request from Lebanon’s Ministry of Environment back in 2013, Oceana has planned and carried out an expedition to survey Lebanese deep-sea canyons and escarpments. Cover: Cerianthus membranaceus © OCEANA All photos are © OCEANA Index 06 Introduction 11 Methods 16 Results 44 Areas 12 Rov surveys 16 Habitat types 44 Tarablus/Batroun 14 Infaunal surveys 16 Coralligenous habitat 44 Jounieh 14 Oceanographic and rhodolith/maërl 45 St. George beds measurements 46 Beirut 19 Sandy bottoms 15 Data analyses 46 Sayniq 15 Collaborations 20 Sandy-muddy bottoms 20 Rocky bottoms 22 Canyon heads 22 Bathyal muds 24 Species 27 Fishes 29 Crustaceans 30 Echinoderms 31 Cnidarians 36 Sponges 38 Molluscs 40 Bryozoans 40 Brachiopods 42 Tunicates 42 Annelids 42 Foraminifera 42 Algae | Deep sea Lebanon OCEANA 47 Human 50 Discussion and 68 Annex 1 85 Annex 2 impacts conclusions 68 Table A1. List of 85 Methodology for 47 Marine litter 51 Main expedition species identified assesing relative 49 Fisheries findings 84 Table A2. List conservation interest of 49 Other observations 52 Key community of threatened types and their species identified survey areas ecological importanc 84 Figure A1.
    [Show full text]
  • Ringiculid Bubble Snails Recovered As the Sister Group to Sea Slugs
    www.nature.com/scientificreports OPEN Ringiculid bubble snails recovered as the sister group to sea slugs (Nudipleura) Received: 13 May 2016 Yasunori Kano1, Bastian Brenzinger2,3, Alexander Nützel4, Nerida G. Wilson5 & Accepted: 08 July 2016 Michael Schrödl2,3 Published: 08 August 2016 Euthyneuran gastropods represent one of the most diverse lineages in Mollusca (with over 30,000 species), play significant ecological roles in aquatic and terrestrial environments and affect many aspects of human life. However, our understanding of their evolutionary relationships remains incomplete due to missing data for key phylogenetic lineages. The present study integrates such a neglected, ancient snail family Ringiculidae into a molecular systematics of Euthyneura for the first time, and is supplemented by the first microanatomical data. Surprisingly, both molecular and morphological features present compelling evidence for the common ancestry of ringiculid snails with the highly dissimilar Nudipleura—the most species-rich and well-known taxon of sea slugs (nudibranchs and pleurobranchoids). A new taxon name Ringipleura is proposed here for these long-lost sisters, as one of three major euthyneuran clades with late Palaeozoic origins, along with Acteonacea (Acteonoidea + Rissoelloidea) and Tectipleura (Euopisthobranchia + Panpulmonata). The early Euthyneura are suggested to be at least temporary burrowers with a characteristic ‘bubble’ shell, hypertrophied foot and headshield as exemplified by many extant subtaxa with an infaunal mode of life, while the expansion of the mantle might have triggered the explosive Mesozoic radiation of the clade into diverse ecological niches. The traditional gastropod subclass Euthyneura is a highly diverse clade of snails and slugs with at least 30,000 living species1,2.
    [Show full text]
  • By C. M. Yonge, D.Se. University of Bristol
    453 EVOLUTION OF CILIARY FEEDING IN THE PROSOBRANCHIA, WITH AN ACCOUNT OF FEEDING IN GAPULUS UNGAR/GUS By C. M. Yonge, D.Se. University of Bristol (Text-figs. 1-6) CONTENTS PAGE Introduction 453 Rejection Currents in the Mantle Cavity of the Prosobranchia 453 Evolution of Ciliary Feeding 455 Vermetus novae-hollandiae . 456 Crepidula fornicata and other Calyptraeidae 457 Capulus ungaricus 459 Modification of gill filaments 461 Discussion. 465 Summary 467 References. 468 INTRODUCTION Ciliary feeding, of such widespread occurrence in the Lamellibranchia, is confined in the Gastropoda to a few scattered groups. In freshwater Pul- monata, such as Limnaea, cilia on the foot assist in feeding when the animal is creeping suspended from the surface film (Brockmeier, 1898). Thecoso- matous Pteropoda feed exclusively by the aid of cilia on the unpaired middle lobe and the paired side lobes of the foot, and an evolutionary series- Cavolinia-Cymbulia-Gleba-can be traced in which there is a progressive elaboration in the perfection of this mechanism and an accompanying reduc- tion in the buccal mass and associated structures handed down from carni- vorous ancestors (Yonge, 1926). Only in the few prosobranchs which have acquired ciliary feeding mechanisms do these represent a modification of the ctenidia as in the Lamellibranchia. They also, as it is the aim of this paper to show, represent a modification of the rejection currents present in the mantle cavity of typical prosobranchs. REJECTION CURRENTS IN THE MANTLE CAVITY OF THE PROSOBRANCHIA In typical Prosobranchia a respiratory current, created by the beating of the lateral cilia on the gill filaments, is drawn into the mantle cavity by way of the inhalent opening (frequently prolonged into a siphon, e.g.
    [Show full text]
  • Albian Rudist Biostratigraphy (Bivalvia), Comanche Shelf to Shelf Margin, Texas
    Carnets Geol. 16 (21) Albian rudist biostratigraphy (Bivalvia), Comanche shelf to shelf margin, Texas Robert W. SCOTT 1, 2 2 Yulin WANG 2 Rachel HOJNACKI Yulin WANG 3 Xin LAI 4 Highlights • Barremian-Albian caprinids biostratigraphic zones are revised and integrated with ammonites and benthic foraminifers. • New caprinid rudist species are the key to revising long-held correlations of Albian strata on the Co- manche shelf, Texas. • On the San Marcos Arch, central Texas, the shallow shelf Person Formation is the upper unit of the Fredericksburg Group. • The Person underlies the basal Washita Group sequence boundary Al Sb Wa1 and the Georgetown Formation. Abstract: Rudists were widespread and locally abundant carbonate producers on the Early Cretaceous Comanche Shelf from Florida to Texas, and on Mexican atolls. As members of the Caribbean Biogeogra- phic Province, their early ancestors emigrated from the Mediterranean Province and subsequently evol- ved independently. Comanchean rudists formed biostromes and bioherms on the shelf interior and at the shelf margin. Carbonate stratigraphic units of the Comanche Shelf record rudist evolution during the Barremian through the Albian ages and an established zonal scheme is expanded. This study documents new Albian rudist occurrences from the Middle-Upper Albian Fredericksburg and Washita groups in Central and West Texas. Rudists in cores at and directly behind the shelf margin southeast of Austin and San Antonio, Texas, complement the rudist zonation that is integrated with ammonites and foraminifers. These new rudist data test long-held correlations of the Edwards Group with both the Fredericksburg and Washita groups based solely on lithologies. Rudist and foraminifer biostratigraphy indicate that the Edwards Group is coeval with the Fredericksburg not the Washita Group.
    [Show full text]
  • Gastropoda, Acteonidae) and Remarks on the Other Mediterranean Species of the Family Acteonidae D’Orbigny, 1835
    BASTERIA, 60: 183-193, 1996 Central Tyrrhenian sea Mollusca: XI. of Callostracon Description tyrrhenicum sp. nov. (Gastropoda, Acteonidae) and remarks on the other Mediterranean species of the family Acteonidae d’Orbigny, 1835 Carlo Smriglio Via di Valle Aurelia 134, 1-00167 Rome, Italy & Paolo Mariottini Dipartimento di Biologia, Terza Universita degli Studi di Roma, Via Ostiense 173, 1-00154 Rome, Italy A new acteonid species, collected in the Central Tyrrhenian Sea, is here described. It is placed in Callostracon and named C. Hamlin, 1884, tyrrhenicum. The description is based on shell morpho- logyonly. Remarks on the four bathyal and the three infralittoral species ofthe familyActeonidae known from the Mediterranean Sea, are also featured. Key-words: Gastropoda, Opisthobranchia, Acteonidae, Callostracon, taxonomy, bathyal fauna, Central Tyrrhenian Sea, Italy. INTRODUCTION In the framework of carried an investigation out over the past decade, we continue to characterize the bathyal faunal assemblages from the Central Tyrrhenian Sea, off the Latial coast (Italy) (Smriglio et al., 1987, 1990, 1992, 1993). In particular, we are interested in the molluscan fauna occurring in the deep-sea coral (biocoenose des and des coraux blancs, CB) muddy-bathyal (biocoenose vases bathyales, VB) commu- nities & of this In this we describe of (Peres Picard, 1964) area. paper a new species acteonid, Callostracon tyrrhenicum, from material dredged in a deep-sea coral bank off the coast. Latial Among the molluscan fauna associated with C. tyrrhenicum, we have iden- tified four which bathyal acteonids, we think worth reporting: Acteon monterosatoi Crenilabium Dautzenberg, 1889, exile (Jeffreys, 1870, ex Forbes ms.), Japonacteon pusillus and Liocarenus (McGillavray, 1843), globulinus (Forbes, 1844).
    [Show full text]
  • ABSTRACT Title of Dissertation: PATTERNS IN
    ABSTRACT Title of Dissertation: PATTERNS IN DIVERSITY AND DISTRIBUTION OF BENTHIC MOLLUSCS ALONG A DEPTH GRADIENT IN THE BAHAMAS Michael Joseph Dowgiallo, Doctor of Philosophy, 2004 Dissertation directed by: Professor Marjorie L. Reaka-Kudla Department of Biology, UMCP Species richness and abundance of benthic bivalve and gastropod molluscs was determined over a depth gradient of 5 - 244 m at Lee Stocking Island, Bahamas by deploying replicate benthic collectors at five sites at 5 m, 14 m, 46 m, 153 m, and 244 m for six months beginning in December 1993. A total of 773 individual molluscs comprising at least 72 taxa were retrieved from the collectors. Analysis of the molluscan fauna that colonized the collectors showed overwhelmingly higher abundance and diversity at the 5 m, 14 m, and 46 m sites as compared to the deeper sites at 153 m and 244 m. Irradiance, temperature, and habitat heterogeneity all declined with depth, coincident with declines in the abundance and diversity of the molluscs. Herbivorous modes of feeding predominated (52%) and carnivorous modes of feeding were common (44%) over the range of depths studied at Lee Stocking Island, but mode of feeding did not change significantly over depth. One bivalve and one gastropod species showed a significant decline in body size with increasing depth. Analysis of data for 960 species of gastropod molluscs from the Western Atlantic Gastropod Database of the Academy of Natural Sciences (ANS) that have ranges including the Bahamas showed a positive correlation between body size of species of gastropods and their geographic ranges. There was also a positive correlation between depth range and the size of the geographic range.
    [Show full text]
  • THE LISTING of PHILIPPINE MARINE MOLLUSKS Guido T
    August 2017 Guido T. Poppe A LISTING OF PHILIPPINE MARINE MOLLUSKS - V1.00 THE LISTING OF PHILIPPINE MARINE MOLLUSKS Guido T. Poppe INTRODUCTION The publication of Philippine Marine Mollusks, Volumes 1 to 4 has been a revelation to the conchological community. Apart from being the delight of collectors, the PMM started a new way of layout and publishing - followed today by many authors. Internet technology has allowed more than 50 experts worldwide to work on the collection that forms the base of the 4 PMM books. This expertise, together with modern means of identification has allowed a quality in determinations which is unique in books covering a geographical area. Our Volume 1 was published only 9 years ago: in 2008. Since that time “a lot” has changed. Finally, after almost two decades, the digital world has been embraced by the scientific community, and a new generation of young scientists appeared, well acquainted with text processors, internet communication and digital photographic skills. Museums all over the planet start putting the holotypes online – a still ongoing process – which saves taxonomists from huge confusion and “guessing” about how animals look like. Initiatives as Biodiversity Heritage Library made accessible huge libraries to many thousands of biologists who, without that, were not able to publish properly. The process of all these technological revolutions is ongoing and improves taxonomy and nomenclature in a way which is unprecedented. All this caused an acceleration in the nomenclatural field: both in quantity and in quality of expertise and fieldwork. The above changes are not without huge problematics. Many studies are carried out on the wide diversity of these problems and even books are written on the subject.
    [Show full text]