DOCSLIB.ORG

Molecular Phylogenetic Status of Some Marine Cymothoid Isopods in Southeast Coast of India

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Molecular Phylogenetic Status of Some Marine Cymothoid Isopods in Southeast Coast of India Molecular phylogenetic status of some marine Cymothoid isopods in southeast coast of India Thangaraj M*., Saranya S., Divya S., Ramanadevi V. & Subburaj J. Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai 608502, TamilNadu, India [*E.mail: [email protected]] Received ; revised In this study, 16S rRNA and COI genes of four Indian isopod species and nine other species (retrieved from NCBI) of the three parasitic habits were examined to present a different hypothesis on the evolutionary history of the family. Present study infers that there is no relationship among the habitat-specific species. Phylogenetic tree support the monophyly of the family and the specialized mouth parts bearing species (endoparasites) are not necessarily derived from the scale attaching ones (ectoparasites). The use of more molecular markers can greatly improve the taxonomic revisions of the Cymothoidae and the present work could be a valuable first step towards this task. [Keywords: Cymothoidae, ectoparasites, mitochondrial gene, phylogeny, evolution] Introduction Cymothoid isopods represent one of the most derived lineages of isopods1,2,3, and currently include 42 genera with over 325 described species and most parasitizing teleost fish, particularly in warm temperate and tropical seas4. In India, earlier study showed the morphology, diversity, 5 life cycle of four isopod parasites and the secondary infection in the host fishes . Some species attach externally, under the scales or at the base of fins, while other more specialized forms inhabit the gill chamber or the buccal cavity, exhibiting very distinctive eco-morphological adaptations and peculiar life-history traits4. Brusca6, initially proposed that the externally attaching forms would represent a distinct lineage from the internal forms, whose specialized adaptations reflect a more derived status. A decade later, a thorough revision was made by Bruce7 and identified three subfamilies, putatively corresponding to three different evolutionary lineages: Anilocrinae, Livonecinae and Cymothoinae. However, careful field observations within the Anilocrinae have shown that some degree of behavioural flexibility can be observed even within a genus8. 1 In general, the distinctive phenotypic adaptations of cymothoids, strongly constrained by the type of parasitic strategy, may hinder the choice of reliable morphological characters suitable for phylogenetic reconstruction9. Despite the power and effectiveness of molecular markers in phylogenetic analysis, their use is seldom strictly confined to the recovery of a pattern of phylogenetic relationships among a set of studied taxa10. In recent years, a number of studies have successfully focused on the positioning of phenotypically measurable adaptive traits on the main branches of the phylogenetic tree of several groups of organisms. These results have proven momentous in the reconstruction of the evolutionary history of several high-profile taxa11,12 and allowed for major reinterpretations of the adaptive transformations that led to the present-day ecological diversity13,14. In this study, we have used 16S rRNA and cytochrome oxidase I (COI) gene of four Indian isopod species and nine other species (retrieved from NCBI) of the three parasitic habits to present a preliminary hypothesis on the evolutionary history of the family. Materials and Methods The parasites were collected along with their host (Elops machnata) from Vellar estuary (Lat 11⁰ 29’ N; Lon 79⁰ 46’ E), Parangipettai, in southeast coast of India. samples were stored in 95% ethanol and sealed with parafilm and kept at room temperature for further analysis. Each collected species were morphologically identified based on the previous report15. The total DNA was extracted from the stored parasites leg tissue by the standard protocol16 with the addition of 5µl Proteinase K and 10% SDS in the digestion buffer. The DNA samples from individuals of each species was diluted to about 25 ng/µl with deionized distilled water and used for polymerase chain reaction. The 16S rRNA gene was amplified using the primers, 16S-cymF 5′-AGCCCTGTTCAA TGGGATTA -3′; 16S-cymR 5′-TCCCTGGGGTAGTTTCATCTT-3′4. The PCR condition was: initial denaturation at 94ºC for 2 min, followed by 35 cycles of 1 min at 95ºC, 30 S at 50ºC and 1 min at 72ºC with a final elongation of 10 min at 72ºC. The COI gene was amplified using the primers, Fish F1 5′-TCAACCAACCACAAAGACATTGGCAC-3′; Fish R1 5′- TAGACTTCTGGGTGGCCAAAGAATCA-3′17. The PCR condition was: initial denaturation at 94ºC for 2 min, followed by 35 cycles of 1 min at 95ºC, 30 S at 54ºC and 1 min at 72ºC with a 2 final elongation of 10 min at 72ºC. The PCR products were purified with a PCR purification kit and sequenced in a commercial sequencing facility (Ramachandra Innovis, Chennai). The gene partial sequences of COI and 16S rRNA from four isopod species were unambiguously edited using BioEdit sequence alignment editor14 and aligned using CLUSTAL- W in BioEdit18 and then checked manually. Another twelve 16S rRNA gene and COI sequences of nine species were retrieved from the GenBank and the details are given in Table1. Analyses were conducted using the Kimura 2-parameter model20. Identical sequences were assigned in the same haplotype identity and only a single example of each species used in the genetic distance (K2P) estimation and assuming that identical haplotypes shared the same evolutionary origin. Phylogenetic and molecular evolutionary analyses, haplotype and nucleotide diversity indices were calculated using MEGA (v. 3.0)21. The model of sequence divergence used was of Tamura22, that accounted for multiple substitutions per site which allowed different substitution rates between transitions and transversions. The neighbour-joining (NJ) trees for the two genes were constructed using MEGA (v. 3.0) and to verify the robustness of the internal nodes of these trees, bootstrap analysis was carried out using 1000 pseudoreplications. Result and Discussion Totally 32 sequences (16S rRNA + COI) from nine isopod species were analysed for its genetic relatedness. Kimura 2 Parameter (K2P) genetic distance in nine isopod species is given in Table 2. Based on the 16S rRNA sequence data, Ceratothoa collaris, Anilocra physodes, Nerocila bivittata and Ceratothoa italica were didn’t show any K2P genetic distance. Whereas, the COI sequence showed the K2P genetic distance was from 0.325 to 0.412 among the four species. The overall K2P distance for 16S rRNA in all the nine species was 0.540 and for COI it was 0.401. Based on 16S rRNA sequence, the K2P genetic distance was high (1.214) between the gill attaching parasite, Pentidotea resecata and the skin parasite, Nerocila poruvae. When we compared the COI gene sequence among the parasites the K2P genetic distance was more (0.860) between the skin parasite, Nerocila orbignyi and the mouth dwelling parasite, Ceratothoa italic. Whereas, the genetic distance was very less (0.235), between the skin parasite, Joryma hilsae and the gill attaching parasite, Lironeca vulgaris. Tajima’s statistics (D) = 1.6270 for 16S rRNA sequence and (D) = 1.8715 for COI gene sequence it was not significantly (p<0.01) different among sequences (Table 3). 3 All the fifteen 16S rRNA and sixteen COI gene sequences were subjected in the phylogenetic analysis. The neighbour joining tree (NJ) of K2P distance was created to provide a graphical representation of the patterning of divergence of nine isopod parasite species. As per 16S rDNA based NJ tree, there are three distinct clades were recognized with high bootstrap value (Fig. 1). The first clad having 100% bootstrap value included both the mouth dwelling and skin parasites. The second clade having 92% bootstrap value included the gill attaching and skin parasites. The third clade having 99% bootstrap value includes only gill attaching parasites. Based on the COI gene data, there were no clear clades that get separated, the NJ tree having seven small clades with more than 50% bootstrap value (Fig. 2). These two mitochondrial genes partial sequences suggests monophyly of cymothoids, but no definitive conclusions can be drawn in this study and this may be due to limited species selection. A molecular phylogenetic framework in Cymothoid isopods was reported in an earlier study4. Where, the tree topology showed the mouth dwelling parasites, Ceratothoa italica and Ceratothoa collaris are sister species to the skin parasite, Nerocila bivittata and Anilocra physodes but the genetic distance did not was not show any significant difference. In the present study, based on the 16S rRNA sequence data, many of the gills attaching parasites were clustered in to one group. But in the case of COI gene sequence based NJ tree, there was no significant grouping topology observed. This may be due to the disparity of the evolutionary rate among the mitochondrial genes. Previous study4 concluded that, due to the nature of habit, many morphological characters commonly used in isopod taxonomy (i.e. setation and external ridges etc) have been lost or greatly reduced and other important characters are highly variable or polymorphic. Earlier reports have identified that three major lineages belongs to the family Cymothoidae: Anilocrinae, Livonecinae and Cymothoinae1,6. The separation of these lineages has until now been based on the fashion of attachment (skin, gill cavity and buccal cavity)4. Bruce7 also suggested that Cymothoid taxonomic arrangements still being based on the host and it may reflect convergence due to similar life-styles rather than true phylogenetic affinities. Our phylogenetic trees also strongly support Bruce’s7 suggestion. Same type of conclusion was given by a recent study4, and they reported that a similar complex of parasitic strategies in Cymothoid isopods and indicate that gill and buccal parasitic habits evolved independently rather than by a direct phylogenetic link. The present study does not allow for a definitive and exhaustive 4 description of the evolution of the ecological diversity in this family. The use of more molecular markers can greatly improve taxonomic revisions of the Cymothoidae, and the present work to be a valuable first step towards this task.
Load more

Recommended publications
  • ANTIOXIDANT CAPACITY in the HEMOLYMPH of the MARINE ISOPOD PENTIDOTEA RESECATA by Leah E. Dann a THESIS Submitted to WALLA WALL
    ANTIOXIDANT CAPACITY IN THE HEMOLYMPH OF THE MARINE ISOPOD PENTIDOTEA RESECATA By Leah E. Dann A THESIS submitted to WALLA WALLA UNIVERSITY in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE April 26, 2017 ABSTRACT The isopod Pentidotea resecata inhabits Zostera marina eelgrass beds. Examination of oxygen levels in a Z. marina bed indicated that P. resecata frequently experience hyperoxia and potential hypoxia reperfusion events in these beds, which may lead to enhanced reactive oxygen species (ROS) production and increased oxidative damage if the antioxidant defenses cannot sufficiently suppress these toxic oxygen intermediates. The total antioxidant capacity of P. resecata hemolymph was compared to that of Ligia pallasii, a semi-terrestrial isopod living in normoxic conditions, and to that of Pandalus danae, a shrimp that lives below the photic zone. The hypothesis was that P. resecata hemolymph would have stronger antioxidant defenses than the other crustaceans because this isopod faces a more hostile oxygen environment. LCMS analysis of P. resecata hemolymph confirmed the presence of antioxidants including pheophorbide a, lutein, and β-carotene, while L. pallasii hemolymph contained pheophorbide a and lutein but no β-carotene. Pandalus danae hemolymph had no carotenoids or pheophorbide. Although L. pallasii hemolymph was missing β-carotene, it had a significantly higher total antioxidant capacity than that of P. resecata. Hemolymph from P. danae had an intermediate antioxidant capacity even though it contained none of the antioxidants detected in the other species. The unexpected antioxidant activities among the species could be explained by differences in metabolic functions or environmental factors that were not examined in this study; or perhaps P.
    [Show full text]
  • Appendix C - Invertebrate Population Attributes
    APPENDIX C - INVERTEBRATE POPULATION ATTRIBUTES C1. Taxonomic list of megabenthic invertebrate species collected C2. Percent area of megabenthic invertebrate species by subpopulation C3. Abundance of megabenthic invertebrate species by subpopulation C4. Biomass of megabenthic invertebrate species by subpopulation C- 1 C1. Taxonomic list of megabenthic invertebrate species collected on the southern California shelf and upper slope at depths of 2-476m, July-October 2003. Taxon/Species Author Common Name PORIFERA CALCEREA --SCYCETTIDA Amphoriscidae Leucilla nuttingi (Urban 1902) urn sponge HEXACTINELLIDA --HEXACTINOSA Aphrocallistidae Aphrocallistes vastus Schulze 1887 cloud sponge DEMOSPONGIAE Porifera sp SD2 "sponge" Porifera sp SD4 "sponge" Porifera sp SD5 "sponge" Porifera sp SD15 "sponge" Porifera sp SD16 "sponge" --SPIROPHORIDA Tetillidae Tetilla arb de Laubenfels 1930 gray puffball sponge --HADROMERIDA Suberitidae Suberites suberea (Johnson 1842) hermitcrab sponge Tethyidae Tethya californiana (= aurantium ) de Laubenfels 1932 orange ball sponge CNIDARIA HYDROZOA --ATHECATAE Tubulariidae Tubularia crocea (L. Agassiz 1862) pink-mouth hydroid --THECATAE Aglaopheniidae Aglaophenia sp "hydroid" Plumulariidae Plumularia sp "seabristle" Sertulariidae Abietinaria sp "hydroid" --SIPHONOPHORA Rhodaliidae Dromalia alexandri Bigelow 1911 sea dandelion ANTHOZOA --ALCYONACEA Clavulariidae Telesto californica Kükenthal 1913 "soft coral" Telesto nuttingi Kükenthal 1913 "anemone" Gorgoniidae Adelogorgia phyllosclera Bayer 1958 orange gorgonian Eugorgia
    [Show full text]
  • OREGON ESTUARINE INVERTEBRATES an Illustrated Guide to the Common and Important Invertebrate Animals
    OREGON ESTUARINE INVERTEBRATES An Illustrated Guide to the Common and Important Invertebrate Animals By Paul Rudy, Jr. Lynn Hay Rudy Oregon Institute of Marine Biology University of Oregon Charleston, Oregon 97420 Contract No. 79-111 Project Officer Jay F. Watson U.S. Fish and Wildlife Service 500 N.E. Multnomah Street Portland, Oregon 97232 Performed for National Coastal Ecosystems Team Office of Biological Services Fish and Wildlife Service U.S. Department of Interior Washington, D.C. 20240 Table of Contents Introduction CNIDARIA Hydrozoa Aequorea aequorea ................................................................ 6 Obelia longissima .................................................................. 8 Polyorchis penicillatus 10 Tubularia crocea ................................................................. 12 Anthozoa Anthopleura artemisia ................................. 14 Anthopleura elegantissima .................................................. 16 Haliplanella luciae .................................................................. 18 Nematostella vectensis ......................................................... 20 Metridium senile .................................................................... 22 NEMERTEA Amphiporus imparispinosus ................................................ 24 Carinoma mutabilis ................................................................ 26 Cerebratulus californiensis .................................................. 28 Lineus ruber .........................................................................
    [Show full text]
  • Distribution and Inferred Evolutionary Characteristics of a Chimeric Ssdna Virus Associated with Intertidal Marine Isopods
    Article Distribution and Inferred Evolutionary Characteristics of a Chimeric ssDNA Virus Associated with Intertidal Marine Isopods Kalia S. I. Bistolas 1,*, Ryan M. Besemer 2,3, Lars G. Rudstam 4 and Ian Hewson 1 1 Department of Microbiology, Cornell University, Ithaca, NY 14850, USA; [email protected] 2 New Visions Life Sciences, Boards of Cooperative Educational Services of New York State, Ithaca, NY 14850, USA; [email protected] 3 University of North Carolina at Wilmington, Wilmington, NC 28403, USA 4 Department of Natural Resources and the Cornell Biological Field Station, Cornell University, Bridgeport, NY 14850, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-607-255-0151 Received: 26 October 2017; Accepted: 23 November 2017; Published: 26 November 2017 Abstract: Aquatic invertebrates are common reservoirs of a rapidly expanding group of circular Rep-encoding ssDNA (CRESS-DNA) viruses. This study identified and explored the phylogenetic relationship between novel CRESS-DNA viral genotypes associated with Pacific intertidal isopods Idotea wosnesenskii, Idotea resecata, and Gnorimosphaeroma oregonensis. One genotype associated with I. wosnesenskii, IWaV278, shared sequence similarity and genomic features with Tombusviridae (ssRNA) and Circoviridae (ssDNA) genomes and was putatively assigned to the Cruciviridae clade comprising chimeric viruses. The complete genome of IWaV278 (3478 nt) was computationally completed, validated via Sanger sequencing, and exhibited sequence conservation and codon usage patterns analogous to other members of the Cruciviridae. Viral surveillance (qPCR) indicated that this virus was temporally transient (present in 2015, but not 2017), specific to I. wosnesenskii at a single collection site (Washington, DC, USA), more prevalent among male specimens, and frequently detected within exoskeletal structures.
    [Show full text]
  • Mediterranean Marine Science
    CORE Metadata, citation and similar papers at core.ac.uk Provided by National Documentation Centre - EKT journals Mediterranean Marine Science Vol. 19, 2018 First record of the isopod Idotea hectica (Pallas, 1772) (Idoteidae) and of the brachyuran crab Matuta victor (Fabricius, 1781) (Matutidae) in the Hellenic waters KONDYLATOS Hydrobiological Station of GERASIMOS Rhodes CORSINI-FOKA MARIA Hellenic Centre for Marine Research, Hydrobiological Station of Rhodes. Cos Street, 85100 Rhodes PERAKIS EMMANOUIL Department of Fisheries Rhodes, South Aegean District. G. Mavrou 2, 85100, Rhodes https://doi.org/10.12681/mms.18106 Copyright © 2018 Mediterranean Marine Science To cite this article: KONDYLATOS, G., CORSINI-FOKA, M., & PERAKIS, E. (2018). First record of the isopod Idotea hectica (Pallas, 1772) (Idoteidae) and of the brachyuran crab Matuta victor (Fabricius, 1781) (Matutidae) in the Hellenic waters. Mediterranean Marine Science, 19(3), 656-661. doi:https://doi.org/10.12681/mms.18106 http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 24/12/2020 06:42:54 | Short Communication Mediterranean Marine Science Indexed in WoS (Web of Science, ISI Thomson) and SCOPUS The journal is available on line at http://www.medit-mar-sc.net DOI: http://dx.doi.org/10.12681/mms.18106 First record of the isopod Idotea hectica (Pallas, 1772) (Idoteidae) and of the brachyuran crab Matuta victor (Fabricius, 1781) (Matutidae) in the Hellenic waters GERASIMOS KONDYLATOS1, MARIA CORSINI-FOKA1 and EMMANOUIL PERAKIS2 1 Hellenic Centre for Marine Research,
    [Show full text]
  • Information Management Plan
    Southern California Bight 2008 Regional Monitoring Survey (Bight’08) Information Management Plan Prepared by: Bight’08 Information Management Committee Prepared for: Commission of Southern California Coastal Water Research Project 3535 Harbor Blvd., Suite 110 Costa Mesa, CA 92626 Version Date: July 30, 2008 Bight 08 Information Management Plan Disclaimer: While we strive to make the Information Management Plan as accurate as possible when we publish it, there may be times at which we may find it necessary to make some minor changes. Please check the data submission website at www.sccwrp.org\datasubmission\bight08 for the most current version of the Information Management Plan and most current values in a given lookup list. If a value seems appropriate for a field but is not listed, please contact the Information Management Officer to discuss its inclusion. 2 Bight 08 Information Management Plan INFORMATION MANAGEMENT COMMITTEE INFORMATION MANAGEMENT CHAIR: Shelly Moore Southern California Coastal Water Research Project INFORMATION MANAGEMENT CO-CHAIRS Shelly Walther Los Angeles County Sanitation District Lisa Haney Los Angeles County Sanitation District INFORMATION MANAGEMENT COMMITTEE MEMBERS: Bruce Bealer Southern California Coastal Water Research Project Cheryl Brantley Los Angeles County Sanitation District Curtis Cash City of LA, Environmental Monitoring Division Susan Chang City of LA, Environmental Monitoring Division Larry Cooper Southern California Coastal Water Research Project Andrea Crumpacker Weston Solutions Mike Mengel Orange County Sanitation District Hai Nguyen Orange County Sanitation District Diane O’Donohue City of San Diego, Metropolitan Wastewater Department Chi-Li Tang Los Angeles County Sanitation District Karin Wisenbaker Aquatic Bioassay Consultants ACKNOWLEDGEMENTS: The Information Management Committee wishes to thank those members of the Field Methods, Chemistry and Toxicity Committees that participated in collaborative process essential to the creation of the Bight’08 Information Management Plan.
    [Show full text]
  • How Does the Green Eelgrass Isopod Pentidotea Resecata Protect Its Tissue Against Highly Fluctuating Oxygen Conditions?
    HOW DOES THE GREEN EELGRASS ISOPOD PENTIDOTEA RESECATA PROTECT ITS TISSUE AGAINST HIGHLY FLUCTUATING OXYGEN CONDITIONS? by CHANUDI JUDELLE JOHNSON A THESIS submitted to WALLA WALLA UNIVERSITY in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 16, 2017 ABSTRACT Organisms that live in hyperoxic or in intermittent hypoxic conditions are likely to be exposed to high levels of reactive oxygen species (ROS). ROS can result in oxidative stress, causing damage to proteins, lipids, and DNA. The green eelgrass isopod Pentidotea resecata lives among Zostera marina eelgrass beds. Because Z. marina lives in shallow water and produces oxygen during photosynthesis, P. resecata lives in a hyperoxic and highly fluctuating oxygen environment, with a range from below 20% to over 200% air saturation. They likely protect themselves against potential damaging ROS with antioxidants. The enzymatic antioxidant capacity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in the tissue of Pentidotea resecata was investigated. The activities of these enzymes were compared to that of Ligia pallasii tissues, a marine isopod that lives terrestrially, occasionally being exposed to the water, and therefore probably only encounters normoxic conditions. Because P. resecata experiences hyperoxic and highly fluctuating oxygen conditions and therefore potentially higher levels of ROS, higher enzymatic antioxidant levels were expected in P. resecata compared to L. pallasii. Instead, the activity of SOD, CAT, and GPx in P. resecata tissues was significantly lower than that of L. pallasii tissues. Perhaps P. resecata have other preventive mechanisms and physical defenses to protect against ROS from highly fluctuating oxygen conditions.
    [Show full text]
  • 1986 an Evaluation of Alternative Technique for Mitigating Impacts Of
    I I fihtsrL,sf, I ffiJ-T'j I AN EVALUATION OT' ALTERNATIVE TECHNIQUES FOR MITIGATING IMPACTS OF TIIE SAN ONOFRE t NUCLEAR GENERAIING STATTON I I t I Richard F. Ambrose Mari-ne Science Institute University of California I Santa Barbara, California 93106 I I I I Prepared for: Marine Review Committee, fnc. 53I Encinitas BIvd., Suite J.05 T Encinj.tas, California 92024 I February, 1986 I I t AN EVALUATTON OF ALTERNAUVE TECHNTQUES FOR MITIGATTNG IUPACTS OF THE SAN ONOFRE NUCLEAR GENERJATINGSTATION TABLE OF CONTENTS EXECUTIVE SI'MMARY aaaaaaaaaaaaaaa ii O.O PREFACE vi 0.1 Purpose of this report ............... vii O.2 Previous work on rnitigation by the MRC vii,i 1.0 INTRODUCTION ..,............ ....... 1 1.1 Mitigation ..... .......... .. r... 1 1.1.1 Definition and General Application I 1.1.2 Procedure in California ..... ..... 6 1.1.3 Application to SONGS 7 L.2 Irnpact Evaluation at SONGS 9 9 13 L4 L7 18 18 I 24 2.I.3 Benthic Invertebrates 33 2.L.4 Plankton 35 2.2 Resource Substitution: Out-of-kind l,titir gation 37 I 2.2.1 Habitat Restoration ..... .. o.. 38 2.2.2 Coastal preservation 4t 2.2.3 Information Acquisition ..... ..... 42 I 2.2.4 Monetary payrnents ..... .o... 43 2.2.5 Water euality Improvement ......... o...... o.... 45 2.3 Mitigation Banking .o..........o.................... 46 prevention 2.4 Loss ..... 48 I 2.4.L rntake .................. r r r.....,... 49 2.4.2 Discharge ............... ...,...... 52 2.4.3 Cooling Towers ............. o.... r. 35 t 2.4.4 Restriction of Operations ....................
    [Show full text]
  • Trophic Interactions Among Fishes a N D Zooplankters Near Shore at Santa Catalina Island, California'
    TROPHIC INTERACTIONS AMONG FISHES AND ZOOPLANKTERS NEAR SHORE AT SANTA CATALINA ISLAND, CALIFORNIA' EDMUNDS. HOBSON AND JAMESR. CHESS^ ABSTRACT Predation pressures from fishes have influenced major evolutionary trends among shallow-water zooplankters, as concluded from study at Santa Catalina Island, Calif. The predominant zooplank- tivorous fishes near shore are actinopterygians, an evolutionary line that has centered around generalized visually feeding, large-mouthed predators. Historically, zooplankters threatened by these fishes have faced selective pressures favoring reduced size, transparency, andlor nocturnal planktonic habits. At present, most zooplankters in the nearshore water column by day are very small (c2 mm, approximately); included are cladocerans, copepods, and various larval forms. Their small size precludes capture by most large-mouthed fishes, thus providing protection in daylight, when the visual sense of generalized predatory fishes is most effective. Larger zooplankters in the water column by day, for example chaetognaths, tend to be transparent. The advantage of transparency to organisms threatened by visually feeding predators is obvious, and is only briefly mentioned here. Zooplankters having sizes (most >2 mm) and other features making them vulnerable to large-mouthed fishes tend to enter the water column only at night, when darkness offers some security from visually feeding predators. Included are polychaetes, mysids, cumaceans, gammaridean and caprellid amphipods, tanaids, isopods, and carideans. Because successful defensive features of prey create pressures that modify the offensive features of predators, the tendencies toward reduced size and nocturnal habits among zooplankters have generated appropriate adaptations among planktivorous fishes. Fishes that prey as adults on zooplankters during the day (e.g., blacksmith, Chromis punetipinnis) have specialized features, including a small highly modified mouth, that permit even relatively large individuals to take the tiny organisms which constitute the daytime zooplankton.
    [Show full text]
  • Idotea Resecata Class: Malacostraca Order: Isopoda a Valviferan Isopod Family: Idoteidae
    Phylum: Arthropoda, Crustacea Idotea resecata Class: Malacostraca Order: Isopoda A valviferan isopod Family: Idoteidae Taxonomy: The genus Idotea was described General Morphology: Isopod bodies are by Fabricius in 1798, and although originally dorso-ventrally flattened and can be divided spelled Idotea, several authors adopted the into a compact cephalon, with eyes, two spelling Idothea, since then. The genus antennae and mouthparts, and a pereon Pentidotea was described by Richardson in (thorax) with eight segments, each bearing 1905 and was reduced to subgeneric level by similar pereopods (hence the name “iso- Menzies in 1950. The two subgenera (or pod”). Posterior to the pereon is the pleon, or genera), Pentidotea and Idotea differ by the abdomen, with six segments, the last of which articles on maxilliped palps, the former with is fused with the telson (the pleotelson) (see five and the latter with four (Miller and Lee Plate 231, Brusca et al. 2007). The Isopoda 1970), but are not always currently can be divided into two groups: ancestral recognized (Rafi and Laubitz 1990). (“short-tailed”) groups (i.e. suborders) that Furthermore, this character may be vary with have short telsons and derived (“long-tailed”) age and other characters may reveal more groups with long telsons. Valviferan concrete differences to define the two (Poore (including the Idoteidae) are a distinct group and Ton 1993). Thus synonyms for I. of isopods (Brusca 1984) and have an resecata include, Idothea resecata, elongated telson (Fig. 73, Ricketts and Calvin Pentidotea resecata and Idotea Pentidotea 1952). resecata. Idothea rufescens may also be a Cephalon: Entire, not notched (compare to synonym having been described from an Mesidotea entomon, this guide), sides of immature specimen (Menzies and Waidzunas head straight.
    [Show full text]
  • Idotea Resecata Class: Multicrustacea, Malacostraca, Eumalacostraca
    Phylum: Arthropoda, Crustacea Idotea resecata Class: Multicrustacea, Malacostraca, Eumalacostraca Order: Peracarida, Isopoda, Valvifera A valviferan isopod Family: Idoteidae Taxonomy: The genus Idotea was de- from fish predation (Best and Stachowicz scribed by Fabricius in 1798, and although 2012). Color polymorphism is high in the con- originally spelled Idotea, several authors gener, I. baltica and variation is determined by adopted the spelling Idothea, since then. habitat and predation pressure but not sexual The genus Pentidotea was described by selection (Jormalainen and Merilaita 1995). Richardson in 1905 and was reduced to General Morphology: Isopod bodies are subgeneric level by Menzies in 1950. The dorso-ventrally flattened and can be divided Pentidotea two subgenera (or genera), and into a compact cephalon, with eyes, two an- Idotea differ by the articles on maxilliped tennae and mouthparts, and a pereon palps, the former with five and the latter with (thorax) with eight segments, each bearing four (Miller and Lee 1970), but are not al- similar pereopods (hence the name “iso- ways currently recognized (Rafi and Laubitz pod”). Posterior to the pereon is the pleon, or 1990). Furthermore, this character may be abdomen, with six segments, the last of which vary with age and other characters may re- is fused with the telson (the pleotelson) (see veal more concrete differences to define the Plate 231, Brusca et al. 2007). The Isopoda two (Poore and Ton 1993). Thus synonyms can be divided into two groups: ancestral I. resecata Idothea resecata for include, , (“short-tailed”) groups (i.e. suborders) that Pentidotea resecata Idotea Pentidotea and have short telsons and derived (“long-tailed”) resecata Idothea rufescens .
    [Show full text]
  • Taxonomic Atlas
    r r r TAXONOMIC ATLAS OF THE BENTHIC FAUNA OF THE SANTA MARIA BASES AND WESTERN SANTA BARBARA CHANNEL - - Volume 11 — The Crustacea Part 2 The Isopoda, Cumacea and Tanaidacea " ^ V* SANTA BARBARA MUSEUM OF NATURAL HISTORY Santa Barbara, California " Research Published in this Volume was Supported by U.S. Department of the Interior Minerals Management Service Pacific OCS Region 770 Paseo Camarillo Camarillo, California 93010 Under Contract No. 14-35-0001-30484 TAXONOMIC ATLAS OF THE BENTHIC FAUNA OF THE SANTA MARIA BASIN AND WESTERN SANTA BARBARA CHANNEL VOLUME 11 The Crustacea Part 2 The Isopoda, Cumacea and Tanaidacea Edited by James A. Blake and Paul H. Scott SANTA BARBARA MUSEUM OF NATURAL HISTORY Santa Barbara, California <jQ \_ NATURAL HISTORY | IGM § libsary § , fs ~2_ gANGF.U=-R BOUNTY 3 V.I I TAXONOMIC ATLAS OF THE BENTHIC FAUNA OF THE SANTA MARIA BASIN AND WESTERN SANTA BARBARA CHANNEL Volume 11 The Crustacea Part 2 - The Isopoda, Cumacea and Tanaidacea ©1997 Santa Barbara Museum of Natural History 2559 Puesta del Sol Road Santa Barbara, California 93105-2936 Original Date of Publication: 20 May 1997 All rights reserved. This book may not be reproduced in whole or in part for any purpose whatever, without written permission from the publisher (Santa Barbara Museum of Natural History). Printed and bound by Alternative Graphics, Goleta, California Production editor, Adele Smith Layout by Marie Murphy Cover photograph by Ron McPeak: An undescribed species of Idoteidae from central California. Photograph digitally enhanced by Marie
    [Show full text]