DOCSLIB.ORG

Physiological and Biochemical Responses of the Intertidal Crabs Hemigrapsus Crenulatus and H

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Physiological and Biochemical Responses of the Intertidal Crabs Hemigrapsus Crenulatus and H Physiological and biochemical responses of the intertidal crabs Hemigrapsus crenulatus and H. sexdentatus to hypoxia and salinity _______________________________________ A thesis submitted in partial fulfilment of the degree of Master of Science in Zoology at the University of Canterbury by Thomas Falconer University of Canterbury 2017 _______________________________________ 1 Table of Contents Acknowledgements ............................................................................................................................... 11 Abstract ................................................................................................................................................. 13 1. General introduction ......................................................................................................................... 16 1.1. Context ....................................................................................................................................... 16 1.2. Environmental change ............................................................................................................... 17 1.2.1. Hypoxia ............................................................................................................................... 18 1.2.2. Salinity ................................................................................................................................. 20 1.3. Physiological and biochemical responses of decapod crabs to environmental stressors ......... 21 1.3. Background and previous physiological research on H. crenulatus and H. sexdentatus ........... 23 1.4. Aims and hypotheses ................................................................................................................. 25 2. Effects of hypoxia and salinity on oxygen uptake in the crabs Hemigrapsus crenulatus and H. sexdentatus ....................................................................................................................................... 28 2.1. Introduction and aims ................................................................................................................ 28 2.2. Collection and maintenance of H. crenulatus and H. sexdentatus ............................................ 31 2.3. Methods and Materials .............................................................................................................. 33 2.4. Results ........................................................................................................................................ 37 2.5. Discussion ................................................................................................................................... 48 3. Heart rate responses of crabs to hypoxia and salinity ...................................................................... 54 3.1. Introduction and aims ................................................................................................................ 54 3.2. Methods and Materials .............................................................................................................. 57 3.3. Results ........................................................................................................................................ 60 3.4. Discussion ................................................................................................................................... 68 4. Biochemical responses of crabs to hypoxia and salinity ................................................................... 73 4.1. Introduction and aims ................................................................................................................ 73 4.2. Methods and Materials .............................................................................................................. 76 4.3. Results ........................................................................................................................................ 80 4.3.1. Osmolarity ........................................................................................................................... 80 4.3.2. Chloride ............................................................................................................................... 86 4.3.3. Potassium ............................................................................................................................ 92 4.3.4. Sodium ................................................................................................................................ 98 4.3.5. Glucose .............................................................................................................................. 104 4.3.6. Haemocyanin .................................................................................................................... 111 4.4. Discussion ................................................................................................................................. 118 5. General Discussion .......................................................................................................................... 132 5.1. Review ...................................................................................................................................... 132 2 5.2. Physiological responses to hypoxia and salinity: Oxygen consumption .................................. 133 5.3. Physiological responses to hypoxia and salinity: Heart rate .................................................... 134 5.4. Biochemical responses to hypoxia and salinity ....................................................................... 134 5.5. Evaluation of methodologies ................................................................................................... 136 5.6. Future studies and research implications ................................................................................ 137 Literature Cited ................................................................................................................................... 140 3 List of Figures Figure 2.1: Photographs of H. crenulatus (left) and H. sexdentatus (right). ........................... 32 Figure 2.2: Photograph of the Waipara beach collection site for H. sexdentatus showing a freshwater stream outlet onto the beach and the collection area for the crabs. 32 Figure 2.3: Photograph showing H. crenulatus within the 400 mL respirometer. .................. 35 Figure 2.4: H. crenulatus oxygen consumption (MO2) under progressive hypoxia (PO2) to the five treatment salinities (2, 25, 50, 100 & 150%). The solid lines show the regression line and the arrows indicate the calculated PCRIT value. ..................... 38 Figure 2.5: H. sexdentatus oxygen consumption (MO2) under progressive hypoxia (PO2) for the five treatment salinities (2, 25, 50, 100 & 150%). The solid lines show the regression line and the arrows indicate the calculated PCRIT value. ..................... 39 Figure 2.6: Oxygen consumption (MO2) values of H. crenulatus under progressively declining oxygen levels (PO2) represented using regression lines. Each regression line represents a different salinity and bold lines indicate that a regression line does not significantly fit the data. ................................................................................. 42 Figure 2.7: Oxygen consumption (MO2) values of H. sexdentatus under progressively declining oxygen levels (PO2) represented using regression lines. Each regression line represents a different salinity and bold lines indicate that a regression line does not significantly fit the data. ........................................................................ 44 Figure 2.8: Oxygen consumption rate (MO2) comparison of H. crenulatus () and H. sexdentatus () under progressively declining oxygen levels (PO2). Each graph represents a different salinity. Solid lines represent the regression lines for H. crenulatus and dashed lines represent the regression lines for H. sexdentatus. Bold lines indicate that a regression line does not significantly fit the data. ....... 46 Figure 3.1: Photographs of H. crenulatus (left) and H. sexdentatus (right) with a rubber ring glued to their carapace and an optical probe fitted within. ................................. 57 Figure 3.2: Photographs showing the container set up for 6 crabs in the water bath. .......... 58 Figure 3.3: Mean heart rate (bpm) ± S.E.M. of H. crenulatus at different dissolved oxygen levels. Plots sharing letters are not significantly different. .................................. 62 Figure 3.4: Mean heart rate (bpm) ± S.E.M. of H. sexdentatus at different dissolved oxygen levels. Plots sharing letters are not significantly different. .................................. 63 4 Figure 3.5: Mean heart rate (bpm) ± S.E.M. of H. crenulatus in differing salinity treatments. There were no significant differences between treatments. ............................... 64 Figure 3.6: Mean heart rate (bpm) ± S.E.M. of H. sexdentatus in differing salinity treatments. Plots sharing letters are not significantly different. ............................................. 65 Figure 3.7: Heart rates of H. crenulatus () and H. sexdentatus () ± S.E.M. in differing salinity treatments. * Significantly different from one another. .......................... 66 Figure 3.8: Heart rates of H. crenulatus () and H. sexdentatus () ± S.E.M. in differing dissolved oxygen treatments. * Significantly different from one another. .......... 67 Figure
Load more

Recommended publications
  • Proximal Composition and Fatty Acid Profile of Hemigrapsus
    Brazilian Journal of Biology https://doi.org/10.1590/1519-6984.231834 ISSN 1519-6984 (Print) Original Article ISSN 1678-4375 (Online) Proximal composition and fatty acid profile ofHemigrapsus crenulatus (H. Milne Edwards, 1837) as one of the main foods of “patagonian blenny”Eleginops maclovinus (Cuvier, 1830) G. Figueroa-Muñoza,b,c , P. De los Ríos-Escalanted,e , P. Dantagnana,f , C. Toledog , R. Oyarzúnh , L. Vargas-Chacoffh , C. Essei and R. Vega-Aguayoa,f* aUniversidad Católica de Temuco, Facultad de Recursos Naturales, Departamento de Ciencias Agropecuarias y Acuícolas, Temuco, Chile bIlustre Municipalidad de Cisnes, Puerto Cisnes, Chile cUniversidad de Concepción, Facultad de Ciencias Naturales y Oceanográficas, Departamento de Zoología, Genomics in Ecology, Evolution and Conservation Laboratory – GEECLAB, Concepción, Chile dUniversidad Católica de Temuco, Facultad de Recursos Naturales, Departamento de Ciencias Biológicas y Químicas, Temuco, Chile eUniversidad Católica de Temuco, Núcleo de Estudios Ambientales, Temuco, Chile fUniversidad Católica de Temuco, Núcleo de Investigación en Producción Alimentaria, Temuco, Chile gUniversidad Católica de Temuco, Facultad de Recursos Naturales, Programa de Doctorado en Ciencias Agropecuarias, Temuco, Chile hUniversidad Austral de Chile, Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias- FONDAP, Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes-IDEAL, Instituto de Ciencias Marinas y Limnológicas, Valdivia, Chile iUniversidad Autónoma de Chile, Facultad de Arquitectura y Construcción, Instituto de Estudios del Hábitat – IEH, Unidad de Cambio Climático y Medio Ambiente – UCCMA, Temuco, Chile *e-mail: [email protected] Received: December 05, 2019 - Accepted: April 07, 2020 - Distributed: August 31, 2021 Abstract The Patagonian blenny (Eleginops maclovinus) is species endemic to South America with physiological characteristics that would facilitate its incorporation into Chilean aquaculture.
    [Show full text]
  • The Stalk-Eyed Crustacea of Peru and the Adjacent Coast
    \\ ij- ,^y j 1 ^cj^Vibon THE STALK-EYED CRUSTACEA OF PERU AND THE ADJACENT COAST u ¥' A- tX %'<" £ BY MARY J. RATHBUN Assistant Curator, Division of Marine Invertebrates, U. S. National Museur No. 1766.—From the Proceedings of the United States National Museum, '<•: Vol.*38, pages 531-620, with Plates 36-56 * Published October 20, 1910 Washington Government Printing Office 1910 UQS3> THE STALK-EYED CRUSTACEA OF PERU AND THE ADJA­ CENT COAST. By MARY J. RATHBUN, Assistant Curator, Division of Marine Invertebrates, U. S. National Museum. INTKODUCTION. Among the collections obtained by Dr. Robert E. Coker during his investigations of the fishery resources of Peru during 1906-1908 were a large number of Crustacea, representing 80 species. It was the original intention to publish the reports on the Crustacea under one cover, but as it has not been feasible to complete them at the same time, the accounts of the barnacles a and isopods b have been issued first. There remain the decapods, which comprise the bulk of the collection, the stomatopods, and two species of amphipods. One of these, inhabiting the sea-coast, has been determined by Mr. Alfred O. Walker; the other, from Lake Titicaca, by Miss Ada L. Weckel. See papers immediately following. Throughout this paper, the notes printed in smaller type were con­ tributed by Doctor Coker. One set of specimens has been returned to the Peruvian Government; the other has been given to the United States National Museum. Economic value.—The west coast of South America supports an unusual number of species of large crabs, which form an important article of food.
    [Show full text]
  • Scavenging Crustacean Fauna in the Chilean Patagonian Sea Guillermo Figueroa-Muñoz1,2, Marco Retamal3, Patricio R
    www.nature.com/scientificreports OPEN Scavenging crustacean fauna in the Chilean Patagonian Sea Guillermo Figueroa-Muñoz1,2, Marco Retamal3, Patricio R. De Los Ríos 4,5*, Carlos Esse6, Jorge Pérez-Schultheiss7, Rolando Vega-Aguayo1,8, Luz Boyero 9,10 & Francisco Correa-Araneda6 The marine ecosystem of the Chilean Patagonia is considered structurally and functionally unique, because it is the transition area between the Antarctic climate and the more temperate Pacifc region. However, due to its remoteness, there is little information about Patagonian marine biodiversity, which is a problem in the face of the increasing anthropogenic activity in the area. The aim of this study was to analyze community patterns and environmental characteristics of scavenging crustaceans in the Chilean Patagonian Sea, as a basis for comparison with future situations where these organisms may be afected by anthropogenic activities. These organisms play a key ecological role in marine ecosystems and constitute a main food for fsh and dolphins, which are recognized as one of the main tourist attractions in the study area. We sampled two sites (Puerto Cisnes bay and Magdalena sound) at four diferent bathymetric strata, recording a total of 14 taxa that included 7 Decapoda, 5 Amphipoda, 1 Isopoda and 1 Leptostraca. Taxon richness was low, compared to other areas, but similar to other records in the Patagonian region. The crustacean community presented an evident diferentiation between the frst stratum (0–50 m) and the deepest area in Magdalena sound, mostly infuenced by Pseudorchomene sp. and a marked environmental stratifcation. This species and Isaeopsis sp. are two new records for science.
    [Show full text]
  • Of the Mud Crab Macrophthalmus Hirtipes (Brachyura: Ocypodidae)
    Marine Biology *2001) 139: 1147±1154 DOI 10.1007/s002270100669 A.D.M. Latham á R. Poulin Effect of acanthocephalan parasites on the behaviour and coloration of the mud crab Macrophthalmus hirtipes Brachyura: Ocypodidae) Received: 22 February 2001 / Accepted: 8 June 2001 / Published online: 16 August 2001 Ó Springer-Verlag 2001 Abstract In the ®eld, the numbers of cystacanths of the nities *Minchella and Scott 1991; Hudson and Green- parasitic acanthocephalan Pro®licollis spp. harboured by man 1998; Poulin 1999). Recent studies have shown that crabs are relatively high and correlate with carapace the relative abundance, or even the actual presence, of width. In a ®eld experiment, the responses of crabs to the certain free-living species in natural communities is en- simulated approach of a bird predator *the parasite's tirely dependent on the action of parasites. For instance, de®nitive host) was not in¯uenced by the number of the outcome of intense, one-sided competition between acanthocephalans they harboured. Crabs that were ex- two species can be changed when a debilitating parasite posed at the surface of the sediments during receding aects the dominant species, allowing the other one to high tide, however, tended to harbour more parasites coexist *Hudson and Greenman 1998). Also, the spatial than nearby crabs hidden in burrows. An analysis of distribution of infected animals may dier from that of colour patterns on the carapace of crabs showed that uninfected conspeci®cs, because of alterations in beha- infection levels did not in¯uence carapace pigmentation, viour caused by parasites; the result is that a portion of and thus did not aect the conspicuousness of a crab the host population may come into contact and interact relative to the background environment.
    [Show full text]
  • Full Text in Pdf Format
    Vol. 30: 85–99, 2021 AQUATIC BIOLOGY Published July 29 https://doi.org/10.3354/ab00743 Aquat Biol OPEN ACCESS FEATURE ARTICLE Impaired larval development at low salinities could limit the spread of the non-native crab Hemigrapsus takanoi in the Baltic Sea Ola Mohamed Nour1,2,*, Christian Pansch3, Mark Lenz1, Martin Wahl1, Catriona Clemmesen1, Meike Stumpp4 1Department of Marine Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany 2Department of Biology and Geology, Faculty of Education, Alexandria University, 21526 Alexandria, Egypt 3Environmental and Marine Biology, Åbo Akademi University, Artillerigatan 6, 20520 Åbo, Finland 4Zoological Institute, Christian-Albrechts University, 24118 Kiel, Germany ABSTRACT: The Asian shore crab Hemigrapsus takanoi, native to the northwest Pacific Ocean, was recently discovered in Kiel Fjord (southwestern Bal - tic Sea). In laboratory experiments, we tested the salinity tolerance of H. takanoi across 8 levels (0 to 35) and across 3 life history stages (larvae, juveniles and adults) to assess its potential to invade the brack- ish Baltic Sea. Larval development at different salin- ities was monitored from hatching to the megalopa stage, while survival and feeding of juveniles and adults were assessed over 17 d. Larvae of H. taka noi were able to complete their development to mega- lopa at salinities ≥ 20 and the time needed after hatch to reach this stage did not differ between salinities of 20, 25, 30 and 35. At a salinity of 15, larvae still reached the last zoea stage (zoea V), but develop- ment to the megalopa stage was not completed. All juveniles and adults survived at salinities from 5 to 35.
    [Show full text]
  • Carry-Over Effects Modulated by Salinity During the Early Ontogeny Of
    Comparative Biochemistry and Physiology, Part A 217 (2018) 55–62 Contents lists available at ScienceDirect Comparative Biochemistry and Physiology, Part A journal homepage: www.elsevier.com/locate/cbpa Carry-over effects modulated by salinity during the early ontogeny of the T euryhaline crab Hemigrapsus crenulatus from the Southeastern Pacific coast: Development time and carbon and energy content of offspring ⁎ Ángel Urzúaa,b, , Miguel Bascura,c, Fabián Guzmána,d, Mauricio Urbinae a Departamento de Ecología, Facultad de Ciencias, Universidad Católica de la Santísima Concepción, Casilla 297, Concepción, Chile b Centro de Investigación en Biodiversidad y Ambientes Sustentables (CIBAS), Universidad Católica de la Santísima Concepción, Concepción, Chile c Programa de Magíster en Ecología Marina, Universidad Católica de la Santísima Concepción, Concepción, Chile d Programa de Magíster en Medio Ambiente, Universidad de Santiago de Chile, Santiago, Chile e Departamento de Zoología, Facultad de Ciencias Naturales y Oceanografía, Universidad de Concepción, Casilla 160-C, Concepción, Chile ARTICLE INFO ABSTRACT Keywords: Hemigrapsus crenulatus is a key species of coastal and estuarine ecosystems in the Southeastern Pacific and New Malacostraca Zealand. Since the gravid females-and their embryos-develop under conditions of variable salinity, we propose Salinity that low external salinity will be met with an increase in energy expenditures in order to maintain osmor- Reproduction egulation; subsequently, the use of energy reserves for reproduction will be affected. In this study, we investigate Life-cycle in H. crenulatus whether 1) the biomass and energy content of embryos is influenced by salinity experienced Cascade effect during oogenesis and embryogenesis and 2) how variation in the biomass and energy content of embryos affects Offspring condition Southeastern Pacific coast larval energetic condition at hatching.
    [Show full text]
  • The Comparative Phylogeography of Shore Crabs and Their Acanthocephalan Parasites
    Marine Biology (2018) 165:69 https://doi.org/10.1007/s00227-018-3326-y ORIGINAL PAPER The comparative phylogeography of shore crabs and their acanthocephalan parasites Eleanor Hay1 · Fátima Jorge1 · Robert Poulin1 Received: 6 December 2017 / Accepted: 19 March 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Comparing the genetic structure of host populations with that of their parasites can shed light on the efciency and inde- pendence of their respective dispersal mechanisms. The degree of congruence between host and parasite genetic structure should refect to what extent they share dispersal mechanisms. Here, we contrast the genetic structure of the acanthocephalan parasite Proflicollis novaezelandensis with that of its intermediate host, the hairy-handed shore crab Hemigrapsus crenulatus, along the east coast of New Zealand’s South Island. We expected no congruence in their phylogeographic patterns because of the very diferent modes of dispersal used by the crabs (planktonic drift) and the acanthocephalans (bird-mediated dis- persal). Based on analysis of cytochrome oxidase subunit I gene sequences, we found no signifcant genetic structure among isolated populations of the crab and those of their parasite, along a roughly 600 km stretch of coastline. Surprisingly, based on a distance-based co-evolutionary analysis statistical tool (PACo), we observed an overall signifcant level of congruence between host and parasite population-level phylogenies. The most parsimonious interpretation is that statistical signifcance does not translate into biological signifcance, with the result likely due to chance, possibly because bird movements that disperse parasites coincidentally match patterns of crab dispersal by ocean currents in parts of our study area.
    [Show full text]
  • The Ecology of the Grapsid Crabs Plagusia Capensis, Leptograpsus Variegatus, Cvclograpsus Insularum and Cvclograpsus Lavauxi in Northern New Zealand
    395 Bacon M.R. (1971a) The ecology of the grapsid crabs Plagusia capensis, Leptograpsus variegatus, Cvclograpsus insularum and Cvclograpsus lavauxi in Northern New Zealand. Unpub. M.Sc. Thesis, University of Auckland. Bacon M.R. (1971b) Distribution and ecology of the crabs Cvclograpsus lavauxi and C.insularum in Northern New Zealand. N.Z. J. Mar. Fresh~at. Res. 5:415-426. Baker A.N. (1971) Food and feeding of kahawai (Teleostei: Arripididae) . N.Z. J. Mar. Freshwat. Res. 5(2):291-299. ". i Baker W.H. (1906) Notes on South Australian decapod , Crustacea, Part 4. Trans. Roy. Soc. South Aust. 30:104-117, pls I-Ill. Balbontin F.C., I.G. Campodonico, &L.M. Guzman.(1979) Descripcion de huevos y larvas de especies de Careproctus (Pisces;Liparidae) comensales de Paralomis granulosa y Lithodes antarctica (Crustacea;Lithodidae). Ans. Inst. Par. 10:235-243. Balss H. (1913) Ostrasiatische Decapoden. I Die Galatheiden und Paguriden. Abhandl. d. math. phys. Klasse der K. Baver. Akademie der Wissenschaften, 11 Supple Bd, 9, Abhandlg. pp 1-85, pls. 1-11, figs 1-54 . Balss H. (1922) Ostrasiatische Decapoden. III Die Dromiacien, Oxystomen und Parthenopiden. IV Die Brachyrhychen (Cancridae). Archiv fur Naturgeschichte 88:104-140, figs 1-9. Balss H. (1929) Decapoden des Roten Meeres. IV Oxyrhyncha und Schlussbetrachtungen. Denkschr. Akad. Wiss. Wien. 102:1-30,Figs 1-9,pl 1. Balss H. (1930) Zoologische Ergebuisse der Reisen von Dr. L. Kohl-Lassen nach den Subaritarktischen Inseln bei Neuseeland und nach Sudgiorgien. Die Dekapoden (Crustaceen). Senckenbergiana 12:195-210, 6 figs. Balss H. (1933) Beitrage zur Kenntris der Gattung Pilumnus (Crustacea Dekapoda) und Verwandter Gattungen.
    [Show full text]
  • Decapoda of the Huinay Fiordos-Expeditions to the Chilean
    ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Spixiana, Zeitschrift für Zoologie Jahr/Year: 2016 Band/Volume: 039 Autor(en)/Author(s): Cesena Feliza, Meyer Roland, Mergl Christian P., Häussermann Vreni (Verena), Försterra Günter, McConnell Kaitlin, Melzer Roland R. Artikel/Article: Decapoda of the Huinay Fiordos-expeditions to the Chilean fjords 2005- 2014: Inventory, pictorial atlas and faunistic remarks 153-198 ©Zoologische Staatssammlung München/Verlag Friedrich Pfeil; download www.pfeil-verlag.de SPIXIANA 39 2 153-198 München, Dezember 2016 ISSN 0341-8391 Decapoda of the Huinay Fiordos-expeditions to the Chilean fjords 2005-2014: Inventory, pictorial atlas and faunistic remarks (Crustacea, Malacostraca) Feliza Ceseña, Roland Meyer, Christian P. Mergl, Verena Häussermann, Günter Försterra, Kaitlin McConnell & Roland R. Melzer Ceseña, F., Meyer, R., Mergl, C. P., Häussermann, V., Försterra, G., McConnell, K. & Melzer, R. R. 2016. Decapoda of the Huinay Fiordos-expeditions to the Chile- an fjords 2005-2014: Inventory, pictorial atlas and faunistic remarks (Crustacea, Malacostraca). Spixiana 39 (2): 153-198. During “Huinay Fiordos”-expeditions between 2005 and 2014 benthic Decapoda (Crustacea: Malacostraca) were collected down to 40 m depth using minimal inva- sive sampling methods. The 889 specimens were attributed to 54 species. The in- fraorder Brachyura was the most speciose with 27 species, followed by Anomura with 18 species, Caridea with 8 species and Dendrobranchiata with one species. Taxonomic examination was complemented by in-situ photo documentation and close-up pictures with extended depth of field taken from sampled individuals showing the species-specific features. Faunistic data was evaluated with location maps and sample localities are discussed according to existing literature, often resulting in the extension of known distribution ranges of various species.
    [Show full text]
  • Molecular Phylogenetic Position of the New Zealand
    MOLECULAR PHYLOGENETIC POSITION OF THE NEW ZEALAND SENTINEL CRAB, MACROPHTHALMUS (HEMIPLAX) HIRTIPES (JACQUINOT, IN HOMBRON & JACQUINOT, 1846) (DECAPODA, BRACHYURA, MACROPHTHALMIDAE) BY JUN KITAURA1),KEIJIWADA1,4), YASUO FUKUI2) and COLIN L. MCLAY3) 1) Department of Biological Science, Faculty of Science, Nara Women’s University, Kitauoya-nishimachi, Nara 630-8506, Japan 2) Osaka University of Arts Junior College, Higashisumiyoshi-ku, Osaka, 546-0023, Japan 3) School of Biological Sciences, University of Canterbury, PB 4800, Christchurch, New Zealand ABSTRACT The systematic position of the New Zealand sentinel crab Macrophthalmus (Hemiplax) hirtipes (Jacquinot, in Hombron & Jacquinot, 1846) has been questioned because the zoeal morphology is incongruent with that of other species assigned to the genus. A molecular phylogeny based on the mitochondrial large subunit (16S) rRNA gene indicates M. hirtipes is distinct from other macrophthalmid species, and found to be more closely related to the New Zealand varunids Austrohelice crassa, Hemigrapsus crenulatus,andHemigrapsus sexdentatus. This indicates that the genus Macrophthalmus Desmarest, 1823 needs to be revised. RÉSUMÉ La position systématique du crabe sentinelle Macrophthalmus (Hemiplax) hirtipes (Jacquinot, in Hombron & Jacquinot, 1846) a été mise en doute car la morphologie de la zoé n’est pas satisfaisante par rapport aux autres espèces de ce genre. Une phylogénie moléculaire basée sur L’ARNr de la grande sous-unité (16S) mitochondriale indique que M. hirtipes est distinct des autres
    [Show full text]
  • H. Milne Edwards, 1837) (Brachyura, Grapsoidea) from a Temperate Estuary in the Eastern South Pacific
    INCIDENCE PATTERNS OF LIMB AUTOTOMY IN THE ESTUARINE CRAB, HEMIGRAPSUS CRENULATUS (H. MILNE EDWARDS, 1837) (BRACHYURA, GRAPSOIDEA) FROM A TEMPERATE ESTUARY IN THE EASTERN SOUTH PACIFIC BY RAMIRO RIQUELME-BUGUEÑO1) Center for Oceanographic Research in the Eastern South Pacific (FONDAP-COPAS), Research Program 3, Marine Biology Station, University of Concepción, P.O. Box 42, Dichato, Concepción, Chile ABSTRACT The first quantitative report about limb autotomy in decapods that inhabit the southeastern Pacific Ocean is here presented. The study analysed samples coming from the south of the Gulf of Arauco, central Chile, of a population of the estuarine crab, Hemigrapsus crenulatus in the course of one year. The number and type of limb lost were registered for each sex. Fifty-two percent of the males and 47% of the females presented at least one limb lost for all samples analysed. Limb types more frequently autotomized were the chelipeds of the males (32%) and the fifth pereiopods of the females (24%). These results indicate that this phenomenon recurs in the population, probably as a consequence of threats from predators or from intraspecific interactions (e.g., cannibalism). RESUMEN Se presenta por primera vez información cuantitativa sobre autotomía de apéndices en decápodos habitantes del Océano Pacífico Sur Oriental. Se analizaron muestras de una población del cangrejo estuarino Hemigrapsus crenulatus por un periodo de un año, provenientes del Golfo de Arauco, Chile central. Se registró el número y tipo de apéndice autotomizado en ambos sexos. El 52% de los machos y el 47% de las hembras presentaron al menos un apéndice autotomizado para el total de las muestras analizadas.
    [Show full text]
  • The Impact Behaviour of Crab Carapaces in Relation to Morphology
    materials Article The Impact Behaviour of Crab Carapaces in Relation to Morphology Puspa Restu Sayekti 1, Fahrunnida 1, Gabrielis Cerniauskas 1 , Colin Robert 1 , Bambang Retnoaji 2 and Parvez Alam 1,* 1 School of Engineering, Institute for Materials and Processes, The University of Edinburgh, Edinburgh EH8 9YL, UK; [email protected] (P.R.S.); [email protected] (F.); [email protected] (G.C.); [email protected] (C.R.) 2 Laboratory of Animal Structure and Development, Department of Tropical Biology, Faculty of Biology, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia; [email protected] * Correspondence: [email protected] Received: 18 August 2020; Accepted: 8 September 2020; Published: 9 September 2020 Abstract: Brachyuran crab carapaces are protective, impact-resistant exoskeletons with elaborate material microstructures. Though several research efforts have been made to characterise the physical, material and mechanical properties of the crab carapace, there are no studies detailing how crab morphologies might influence impact resistance. The purpose of this paper is to characterise and compare Brachyuran crab carapace morphologies in relation to their impact properties, using opto-digital, experimental and numerical methods. We find that crab carapaces with both extended carapace arc-lengths and deep carapace grooves lose stiffness rapidly under cyclic impact loading, and fail in a brittle manner. Contrarily, carapaces with smaller arc lengths and shallower, more broadly distributed carapace grooves are more effective in dissipating stresses caused by impact throughout the carapace structure. This allows them to retain stiffness for longer, and influences their failure mode, which is ductile (denting), rather than brittle fracture.
    [Show full text]