Phoronis Pallida Class

Total Page:16

File Type:pdf, Size:1020Kb

Phoronis Pallida Class Phylum: Phoronida Class: Phoronis pallida Order: A lophophorate coelomate Family: Phoronidae Description 1959). Size: one of the smaller phoronids: 15-30 Collar: not present at base of lophophore: ge- mm long (Silen 1954): sp. pallida. Sand cov- nus Phoronis (Zimmer 2007) (figs. 1, 2, 3). ered tube just a little larger (Silen 1952); ex- Lophophore base and trunk demarcation a panded animal can be 25% longer than slight groove; collar, (if present, as in genus tube. Phoronopsis), extends all around trunk. (Do Color: trunk pale, white, posterior end light not confuse anus and nephridiopores on dor- red. Internal organs visible as red (contain sal base of lophophore with a true collar.) hemoglobin (Zimmer and Haderlie 1980). Bulb: (ampulla)-enlarged posterior end (fig. Tentacles white, without pigmented amoebo- 1). cytes: sp. pallida (Silen 1954). Larva opaque Internal Structure: much systematic work yellow, tube yellow to brown-red (from se- based on longitudinal muscle patterns, etc., creted matter) (Silen 1954). not easily studied by casual field worker. P. Trunk: wormlike: unsegmented, smooth and pallida muscles have unusual longitudinal and soft, but faintly annulated (Hyman 1959), no circular patterns, and few bundles of muscles setae - all characteristic of phylum Phoroni- (18-19). Giant nerve fibers found in this phy- da. Can be faintly differentiated into several lum - except in P. ovalis - also vary in size zones: sp. pallida (Silen 1954). Trunk and and number. P. pallida has one giant nerve whole tube curved toward anal side (Silen fiber, on the left side - usual position in phy- 1954) (fig. 6). lum (Emig 1974). Nephridial structure is also Lophophore: a horseshoe-shaped exten- important in systematics. sion of the mesosome (Hyman 1959); in- Tube: separate, vertical, chitinous, covered cludes mouth and consists of a crown of ten- with thin layer of sand grains. Membranous tacles. Number of lophophore spirals, num- distally (Zimmer 2007). Distinctly flexed 1/3 of ber of tentacles characteristic of sp. pallida - way to base: sp. pallida (Silen 1954) (fig. 6). a single row of 50-140 tentacles, in a simple Tube flexible, tough, can't be easily broken. spiral (Emig 1974)(fig. 3). Basal end of tube open. Tentacles: straight, finger-shaped: Phoroni- Larva: actinotroch (from which this species da (Zimmer and Haderlie 1980); not thread- was first described (Schneider 1862)) is small: like (fig. 2a). In P. pallida there can be 50- 0.6 mm long, active; found on water's surface. 140, but usually around 50 (Zimmer and Mature larva found on substrate, has 5 pairs Haderlie 1980), sometimes more (S.F. Bay of tentacles (Silen 1954) (fig. 5). Young ac- specimens). Tentacles can be regenerated tinotrochs are photopositive and (MacGinitie and MacGinitie 1949). planktotrophic (Silen 1954). Anus: dorsal to mouth (Hyman 1959); di- Possible Misidentifications gestive tract U-shaped (fig. 2). Phoronids are worm-like, with an un- Nephridiopores: lateral to anus (fig. 2): ex- segmented, though slightly annulated trunk cretory and for emission of sex cells (Hyman and a crown of tentacles on the anterior end. A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Meyer, K. 2015. Phoronis pallida. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biology, Charleston, OR. Some polychaetes also have this general There are 4 other species of Phoronis form. Phoronids, however, have no setae or reported from our coast: segmentation on their trunks. Phoronid ten- P. architecta Andrews, 1890 is an At- tacles are straight and finger-like, not lantic species, also found subtidally from branched or thread-like, as in polychaetes. southern California to British Columbia, and The phoronid lophophore is circular - cres- occasionally intertidally (Zimmer and Hader- cent shaped or a double spiral. lie 1980). Its lophophore is flesh-colored, or Only 2 genera of Phoronida and rarely reddish, with white bands and flecks. It probably fewer than 20 species are known has no collar, (like P. pallida), but is 2x the worldwide. Many of these can be found on size of the latter; its sand encrusted tube is the Pacific coast, but only 3 are common straight, not flexed. P. psammophila has intertidally: Phoronopsis harmeri, Phoronis been synonymized with P. architecta (Emig vancouverensis, and P. pallida. The main 1982).P. ovalis Wright, 1856 is much smaller population of each of these species is likely even than P. pallida, (only 6 mm long). It subtidal (Zimmer 2007). bores in shell and limestone and is not found Phoronopsis spp. can be distin- living freely in the mud. guished from Phoronis spp. by the pres- P. vancouverensis Pixell, 1912 (now ence in the former of a collar at the base of senior synonym of P. ijimai Oka, 1897) is the lophophore, lacking in Phoronis spp. whitish, like P. pallida. It is larger, however, The 3 Pacific representatives of this genus 20-50 mm long, and has 72-100 tentacles include: (average 90 (Pixell 1912)), and grows in in- Phoronopsis harmeri Pixell, 1912 tertwined clusters of great density, often on (senior synonym of P. viridis Hilton, 1930), pilings and on rocks. Its tubes are covered a large common phoronid often found in with detritus, not sand grains. great masses on the mudflats. Individuals P. hippocrepia (Wright), the European can be green or white and up to 200 mm species, is considered to be separate from P. long, with up to 300 green tentacles with vancouverensis above (Emig 1971). white spots (Hyman 1959, Zimmer 2007). Ecological Information P. harmeri is usually larger than P. pallida Range: Scandinavia; Pacific coast of North (up to 60 mm long), and has a collar, as in America. all Phoronopsis spp. It is also found in the Local Distribution: Coos Bay: Charleston Atlantic (Azores). This species is abundant mudflats. on Oregon and Washington tidal flats, and Habitat: in soft sand, muddy sand (Emig is largely distinguished from P. pallida by its 1974); on intertidal mudflats. Commensal in size, color and its collar. Upogebia pugettensis burrows (Zimmer 2007) P. pacifica (Torrey, 1901), found first Salinity: all phoronids are marine (Zimmer in Humboldt Bay, and described from Puget and Haderlie 1980). Only one species, P. eux- Sound as well, is also considered a syno- inicola, is found in brackish water, in the Black nym of P. harmeri (Emig 1974). Sea (Hyman 1959). These specimens collect- The 3rd Phoronopsis species, P. cali- ed at 30 ‰ (Coos Bay). fornica Hilton, 1930, is probably limited to Temperature: phoronids are found in shallow southern California. It has a large bright or- waters of tropical and temperate ranges ange lophophore with elaborate spirals; it is (Hyman 1959); most are temperate (Zimmer solitary, and can be up to 12" (300 mm) 1980). Some can regenerate after extremes long (MacGinitie and MacGinitie 1949). A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] of weather have left only fragments in tubes: havior is induced by a waterborne cue from in winter (Italy) and summer (Japan) (Hyman Upogebia pugettensis, a shrimp species with 1959). which P. pallida is commensal (Santagata Tidal Level: intertidal, also subtidal at a 2004b). Metamorphosis is triggered by pres- number of locations worldwide(Zimmer ence of proper substrate (mud, sand), and 2007) down to 12m deep (Emig 1974). takes 15 minutes. The actinotroch takes a (Other phoronids can be found down to horizontal position, ventral side down, then 140m.) evaginates metasomal sac. The transition is Associates: commensal in burrows of made from control by the larval neuromuscu- Upogebia pugettensis, though not often lar system to that of the juvenile, resulting in found with the sympatric mud shrimp Ne- the apoptosis of larval structures. This suc- otrypaea californiensis (Zimmer 2007). cession of events suggests lophotrochozoan Abundance: affinities (Santagata 2002). Finally, a thin tube is formed, and the worm begins to burrow. Life-History Information Food: all phoronids are ciliary mucus feeders, Reproduction: a simultaneous hermaphro- gathering suspended particles by tentacular dite: eggs and sperm extruded into body currents (Hyman 1959). Actinotrochs eat cavity from reproductive organs, fertile eggs peridinians, not diatoms (Silen 1952). expelled into seawater via nephridiopores Predators: (MacGinitie and MacGinitie 1949). In some Behavior: movement limited to emergence species, larvae live among tentacles of adult from anterior end of tube, and expansion of female, but not in P. pallida, which lacks crown (in undisturbed conditions), and to with- nidamental (nesting) organs (Emig 1974). drawal into tube if disturbed (Hyman 1959). No asexual propagation, although regenera- Adults not light sensitive (Hyman 1959). tion of crown of tentacles possible (Silen 1952). Eggs laid on 2 - 3 successive sum- Bibliography mer nights (Sweden), 28 at a time (Silen 1. EMIG, C. C. 1971. Remarques sur la 1954). systmatique des Phoronidea. Marine Biol- Larva: ogy . 8:154-159. Juvenile: 2. ——. 1974. The systematics and evolution Longevity: of the phylum Phoronida. Journal of Zoo- Growth Rate: fertilized egg immobile for 20 logical Systematics and Evolutionary Re- hours; to blastula stage in 20 hours more. search. 12:128-151. After gastrulation begins, hood develops; in 3. EMIG, C.C. 1982. The biology of Phoroni- 25-30 more hours, a ciliated ridge appears, da. Advances in Marine Biology. 19: 1-89. which becomes the crown of tentacles. First 4. HYMAN, L. H. 1959. The Invertebrates: tentacles show after 2 days.
Recommended publications
  • Development, Organization, and Remodeling of Phoronid Muscles from Embryo to Metamorphosis (Lophotrochozoa: Phoronida) Elena N Temereva1,3* and Eugeni B Tsitrin2
    Temereva and Tsitrin BMC Developmental Biology 2013, 13:14 http://www.biomedcentral.com/1471-213X/13/14 RESEARCH ARTICLE Open Access Development, organization, and remodeling of phoronid muscles from embryo to metamorphosis (Lophotrochozoa: Phoronida) Elena N Temereva1,3* and Eugeni B Tsitrin2 Abstract Background: The phoronid larva, which is called the actinotrocha, is one of the most remarkable planktotrophic larval types among marine invertebrates. Actinotrochs live in plankton for relatively long periods and undergo catastrophic metamorphosis, in which some parts of the larval body are consumed by the juvenile. The development and organization of the muscular system has never been described in detail for actinotrochs and for other stages in the phoronid life cycle. Results: In Phoronopsis harmeri, muscular elements of the preoral lobe and the collar originate in the mid-gastrula stage from mesodermal cells, which have immigrated from the anterior wall of the archenteron. Muscles of the trunk originate from posterior mesoderm together with the trunk coelom. The organization of the muscular system in phoronid larvae of different species is very complex and consists of 14 groups of muscles. The telotroch constrictor, which holds the telotroch in the larval body during metamorphosis, is described for the first time. This unusual muscle is formed by apical myofilaments of the epidermal cells. Most larval muscles are formed by cells with cross-striated organization of myofibrils. During metamorphosis, most elements of the larval muscular system degenerate, but some of them remain and are integrated into the juvenile musculature. Conclusion: Early steps of phoronid myogenesis reflect the peculiarities of the actinotroch larva: the muscle of the preoral lobe is the first muscle to appear, and it is important for food capture.
    [Show full text]
  • Ground Plan of the Larval Nervous System in Phoronids: Evidence from Larvae of Viviparous Phoronid
    DOI: 10.1111/ede.12231 RESEARCH PAPER Ground plan of the larval nervous system in phoronids: Evidence from larvae of viviparous phoronid Elena N. Temereva Department of Invertebrate Zoology, Biological Faculty, Moscow State Nervous system organization differs greatly in larvae and adults of many species, but University, Moscow, Russia has nevertheless been traditionally used for phylogenetic studies. In phoronids, the organization of the larval nervous system depends on the type of development. With Correspondence Elena N. Temereva, Department of the goal of understanding the ground plan of the nervous system in phoronid larvae, the Invertebrate Zoology, Biological Faculty, development and organization of the larval nervous system were studied in a viviparous Moscow State University, Moscow 119991, phoronid species. The ground plan of the phoronid larval nervous system includes an Russia. Email: [email protected] apical organ, a continuous nerve tract under the preoral and postoral ciliated bands, and two lateral nerves extending between the apical organ and the nerve tract. A bilobed Funding information Russian Foundation for Basic Research, larva with such an organization of the nervous system is suggested to be the primary Grant numbers: 15-29-02601, 17-04- larva of the taxonomic group Brachiozoa, which includes the phyla Brachiopoda and 00586; Russian Science Foundation, Phoronida. The ground plan of the nervous system of phoronid larvae is similar to that Grant number: 14-50-00029 of the early larvae of annelids and of some deuterostomians. The protostome- and deuterostome-like features, which are characteristic of many organ systems in phoronids, were probably inherited by phoronids from the last common bilaterian ancestor.
    [Show full text]
  • Embryogenesis and Larval Development of Phoronopsis Harmeri Pixell, 1912 (Phoronida): Dual Origin of the Coelomic Mesoderm
    Invertebrate Reproduction and Development, 50:2 (2007) 57–66 57 Balaban, Philadelphia/Rehovot 0168-8170/07/$05.00 © 2007 Balaban Embryogenesis and larval development of Phoronopsis harmeri Pixell, 1912 (Phoronida): dual origin of the coelomic mesoderm ELENA N. TEMEREVA* and VLADIMIR V. MALAKHOV Biological Faculty, Invertebrate Zoology, Moscow State University, Moscow 119992, Russia Tel. and Fax: +8 (495) 939-4495; email: [email protected] Received 12 December 2006; Accepted 26 March 2007 Summary Phoronids are marine invertebrates which great significance from the perspective of comparative anatomy. Phoronids have traditionally been described as deuterostomes because they exhibit developmental and larval traits similar to those traits found in echinoderms and hemichordates. However, molecular phylogenetic evidence has consistently identified the phoronids and brachiopods as a monophyletic group within the lophotrochozoan protostomes. The nature of egg cleavage, gastrulation and the origin of coelomic mesoderm can help to resolve this contradiction. These questions were investigated with Phoronopsis harmeri. Embryos and actinotroch larvae were cultivated in the laboratory, and embryonic and larval development was followed with SEM, light and video microscopy. Egg cleavage is radial, although the furrows of the 4th and succeeding divisions are oblique, which allows for blastula formation by the 16-cell stage. The ciliated blastula hatches 10 h after the onset of cleavage and acquires the apical tuft. Gastrulation proceeds by invagination. Coelomic mesoderm derives from two, the anterior and posterior, precursors. The anterior precursor forms by cell migration from the anterior wall of the archenteron, the posterior one by enterocoelic outpouching of the midgut. The lining of preoral coelom and tentacle coelom is derived from the anterior precursor, whilst the lining of trunk coelom originates from the posterior one.
    [Show full text]
  • Lophotrochozoa, Phoronida): the Evolution of the Phoronid Body Plan and Life Cycle Elena N
    Temereva and Malakhov BMC Evolutionary Biology (2015) 15:229 DOI 10.1186/s12862-015-0504-0 RESEARCHARTICLE Open Access Metamorphic remodeling of morphology and the body cavity in Phoronopsis harmeri (Lophotrochozoa, Phoronida): the evolution of the phoronid body plan and life cycle Elena N. Temereva* and Vladimir V. Malakhov Abstract Background: Phoronids undergo a remarkable metamorphosis, in which some parts of the larval body are consumed by the juvenile and the body plan completely changes. According to the only previous hypothesis concerning the evolution of the phoronid body plan, a hypothetical ancestor of phoronids inhabited a U-shaped burrow in soft sediment, where it drew the anterior and posterior parts of the body together and eventually fused them. In the current study, we investigated the metamorphosis of Phoronopsis harmeri with light, electron, and laser confocal microscopy. Results: During metamorphosis, the larval hood is engulfed by the juvenile; the epidermis of the postroral ciliated band is squeezed from the tentacular epidermis and then engulfed; the larval telotroch undergoes cell death and disappears; and the juvenile body forms from the metasomal sack of the larva. The dorsal side of the larva becomes very short, whereas the ventral side becomes very long. The terminal portion of the juvenile body is the ampulla, which can repeatedly increase and decrease in diameter. This flexibility of the ampulla enables the juvenile to dig into the sediment. The large blastocoel of the larval collar gives rise to the lophophoral blood vessels of the juvenile. The dorsal blood vessel of the larva becomes the definitive median blood vessel.
    [Show full text]
  • Documenting Neotropical Diversity of Phoronids with DNA Barcoding of Planktonic Larvae
    Received: 30 April 2018 | Revised: 25 January 2019 | Accepted: 17 February 2019 DOI: 10.1111/ivb.12242 ORIGINAL ARTICLE Documenting neotropical diversity of phoronids with DNA barcoding of planktonic larvae Rachel Collin1 | Dagoberto E. Venera‐Pontón1 | Amy C. Driskell2 | Kenneth S. Macdonald2 | Kit‐Yu Karen Chan3 | Michael J. Boyle4 1Smithsonian Tropical Research Institute, Balboa, Ancon, Panama Abstract 2Laboratories of Analytical Biology, National Phoronid larvae, actinotrochs, are beautiful and complicated organisms which have Museum of Natural History, Smithsonian attracted as much, if not more, attention than their adult forms. We collected acti‐ Institution, Washington, DC 3Division of Life Science, The Hong Kong notrochs from the waters of the Pacific and Caribbean coasts of Panama, and used University of Science and Technology, Clear DNA barcoding of mtCOI, as well as 16S and 18S sequences, to estimate the diversity Water Bay, Hong Kong of phoronids in the region. We discovered three operational taxonomic units (OTUs) 4Smithsonian Marine Station, Fort Pierce, Florida in the Bay of Panama on the Pacific coast and four OTUs in Bocas del Toro on the Caribbean coast. Not only did all OTUs differ from each other by >10% pairwise dis‐ Correspondence Rachel Collin, Smithsonian Tropical tance in COI, but they also differed from all phoronid sequences in GenBank, includ‐ Research, Institute, Unit 9100, Box 0948, ing the four species for which adults have been reported for the Pacific of Panama, DPO AA 34002, USA Email: [email protected] Phoronopsis harmeri, Phoronis psammophila, Phoronis muelleri, and Phoronis hippocre‐ pia. In each ocean region, one common OTU was more abundant and occurred more Present Address Kit‐Yu Karen Chan, Biology frequently than other OTUs in our samples.
    [Show full text]
  • Larval Development, the Origin of the Coelom and the Phylogenetic Relationships of the Phoronida
    5 General Introduction With eleven valid species, Phoronida constitutes a small group of exclusively marine coelomate animals. According to Hyman (1959) Phoronida are grouped within Bryozoa (Ectoprocta) and Brachiopoda as Tentaculata or Lophophorata. The monophyly of the Tentaculata (Cohen 2000, Cohen & Weydmann 2005, Lüter 2000) lacks suffi cient support and the phylogenetic position of the taxa constituting it within the Bilateria (see Lüter & Bartolomaeus 1997, Adoutte et al. 2000, Giribet et al. 2000, Zrzavý 2001, Giribet 2002, Zrzavý 2003) remains contorversial. This uncertainty primarily results from incongruity of the morphological and molecular data. All representatives of the phoronids are sessile and live in tubes consisting of chitin, in which they can move and anchor themselves by antagonistic muscle activity and by the aid of the trunk coelom that functions as a hydroskeleton (Hyman 1959). Phoronids feed on organic material, which they fi lter out of the water column with their perioral tentacles. Morphologically, the tentacles originate from a horseshoe shaped ridge, the lophophor. The lophophor contains the tentacle coelom or mesocoel, which surrounds the oesophagus and sends extensions into the tentacles. The mouth opening is situated in the center of the tentacular ridge. The epistome, which is a muscular lobe that is used to push the infi ltrated particles into the mouth opening, overhangs the mouth opening (Pross 1974). Entering the mouth the food particles are passed through the U-shaped gut by ciliary action. The gut opens to the outside via the anus, which is situated on a small anal papilla just outside the tentacular ridge. The nephropori of the metanephridia that drain the trunk coelom or meta- coel are located on the left and right sides of the anal opening.
    [Show full text]
  • Synopses of the British Fauna (New Series) Edited by Doris M
    Synopses of the British Fauna (New Series) edited by Doris M. Kermack and R.S.K. Barnes A NEW SERIES No. 13 Synopses of the British Fauna No. 13 •• rl 15 an Edited by Doris M. Kermack and R. S. K. Barnes • er oronl 5 c.c. Emig BRITISH AND OTHER PHORONIDS Keys and Notes for the Identification of the Species C. c. EMIG Station Marine d' Endoume, Rue de la Batterie-des-Lions, 13007 Marseilles, France 1979 Published for THE LINNEAN SOCIETY OF LONDON and THE ESTUARINE AND BRACKISH-WATER SCIENCES ASSOCIATION by The Linnean Society ACADEMIC PRESS of London LONDON, NEW YORK AND SAN FkANCISCO Academic Press London New York San Francisco ACADEMIC PRESS INC. (LONDON) L TD 24-28 Oval Road London, NWl 7DX V.S. Edition published by ACADEMIC PRESS INC 111 Fifth Avenue New York, New York 10003 Foreword Ilhoronids are a small, but widely distributed, group of benthic marine animals. Copyright © 1979 by the Linnean Society of London and the Estuarine and Brackish­ I'or the first time in English, Dr Emig has provided keys and descriptions to water Sciences Association Iluble not only the British species to be identified but also all other known p 'ics. The size of this synopsis and a glance at the maps show that little is kllown of these tube-dwelling, worm-like invertebrates. It is also the reason for All Rights Reserved th' cditors decision to extend the coverage of this synopsis to include full I1 scriptions of species of phoronids occurring outside British waters. The author lllld cditors are anxious to receive new records of localities with phoronids, so No part of this book may be reproduced in any form by photostat, microfilm, or any other thUI the group may become better known and understood.
    [Show full text]
  • The Biology of Phoronida
    Adz). Ma? . Bid .. V0l . 19. 1982. pp . 1-89 . THE BIOLOGY OF PHORONIDA C . C . EMIG Station Marine d'Endoume (Laboratoire associe' au C.N.R.S.41), 13007 Marseille. France I . Introduction .......... .. .. .. .. 2 I1 . Systematics .......... .. .. .. .. .. 2 I11 . Reproduction and Embryonic Development .. .. .. .. .. 5 A . Sexual patterns and gonad morphology .. .. .. .. 5 B . Oogenesis .......... .. .. .. .. .. 8 C. 'Spermiogenesis ........ .. .. .. .. .. 8 D . Release of spermatozoa ...... .. .. .. .. .. 9 E . Fertilization ........ .. .. .. .. .. 13 F . Spawning .......... .. .. .. .. .. 14 G . Embryonic development ..... .. .. .. .. .. 14 H . Embryonic nutrition ...... .. .. .. .. .. 17 IV . Actinotroch Larvae ........ .. .. .. .. .. 17 A . General account ........ .. .. .. .. .. 17 B . Development of the actinotroch species .. .. .. .. .. 21 C . Larval settlement and metamorphosis . .. .. .. .. .. 31 D . Metamorphosis ........ .. .. .. .. .. 33 V . Ecology ............ .. .. .. .. .. 38 A . Tube ........... .. .. .. .. .. 38 B . Biotopes .......... .. .. .. .. .. 43 C. Ecological effects ........ .. .. .. .. .. 47 D . Predators of Phoronida ...... .. .. .. .. .. 49 E . Geographical distribution .... .. .. .. .. .. 50 VI . Fossil Phoronida ......... .. .. .. .. .. 50 VII. Feeding ............ .. .. .. .. .. 53 A . Lophophore and epistome .... .. .. .. .. .. 53 B . Mechanisms of feeding ...... .. .. .. .. .. 56 C. The alimentary canal ...... .. .. .. .. .. 57 D . Food particles ingested by Phoronida . .. .. .. .. .. 61 E . Uptake of
    [Show full text]
  • Development and Organization of the Larval Nervous System in Phoronopsis Harmeri: New Insights Into Phoronid Phylogeny Elena N Temereva1* and Eugeni B Tsitrin2
    Temereva and Tsitrin Frontiers in Zoology 2014, 11:3 http://www.frontiersinzoology.com/content/11/1/3 RESEARCH Open Access Development and organization of the larval nervous system in Phoronopsis harmeri: new insights into phoronid phylogeny Elena N Temereva1* and Eugeni B Tsitrin2 Abstract Background: The organization and development of the nervous system has traditionally been used as an important character for establishing the relationships among large groups of animals. According to this criterion, phoronids were initially regarded as deuterostomian but have more recently been regarded as protostomian. The resolving of this conflict requires detailed information from poorly investigated members of phoronids, such as Phoronopsis harmeri. Results: The serotonin-like immunoreactive part of the P. harmeri nervous system changes during larval development. These changes mostly concern the nervous system of the hood and correlate with the appearance of the median and two marginal neurite bundles, the frontal organ, and the sensory field. The apical organ has bilateral symmetry. The tentacular neurite bundle passes under the tentacles, contains several types of perikarya, and gives rise to intertentacular bundles, which branch in the tentacle base and penetrate into adjacent tentacles by two lateroabfrontal bundles. There are two groups of dorsolateral perikarya, which exhibit serotonin-like immunoreactivity, contact the tentacular neurite bundle, and are located near the youngest tentacles. Larvae have a minor nerve ring, which originates from the posterior marginal neurite bundle of the hood, passes above the tentacle base, and gives rise to the mediofrontal neurite bundle in each tentacle. Paired laterofrontal neurite bundles of tentacles form a continuous nerve tract that conducts to the postoral ciliated band.
    [Show full text]
  • Reproductive Biology of Invertebrates
    REPRODUCTIVE BIOLOGY OF INVERTEBRATES K.G. and RITA-.G. ADIYODl 1"-:>oJoo.. c..... <f ,"wrm..- ~ C4Ik>o /hoI.",IIy, "MIld ~7J1ill. _ VOLUME lV, PART B t'<rtiIiuUooo. oe_<lnpnonI...... I'lraltal car. OXRlII;O" lBH !"UBUSHINO CO. I">"f. LT1), ,,~w llE1.m Il()I,IB~Y CALCl1lTA 8. PHORONIDA CHRISTIAN C. EMIG Station Marine d' Endoume. Rile de la Batterie-des-Lions, 13007 Marseille, France I. INTRODUCTION Historical aspects of the development of phoronids are summarized by Selys~ Longchamps (1907), Cori (1939), and Hyman (1959) and will not be considered here. The phylogenclic relationships of the phoronids, some of which are drawn from studies on embryonic and larval development (see Emig. 1976.1982.1985 for discussion), have been controversial. Only the more recent interpretations are in­ cluded in this article and this has been done with a view to stimulate future invesliga~ lions. The terminology, used here, is as proposed by Emig (1975). 11. MODE OF INSEMINATION A. Sperm Transfer via Spermatophore 1. Types of spermatophore Spermatophore formation is ofgeneral occurrence in phoronids (except in Phoronis ovalis in which lophophoral organs are absent). Some authors (e.g. Ikeda. 1903; Rattenbury, 1953; Silen. 1954) have observed a discharge of spermatozoa directly into the sea water, but this should be considered an exception. Two types of spermatophores (Fig. I) have been distinguished in phoronids (Zim­ mer, 1967; Emig, 1982). The A type consists of an ovoid mass of spermatozoa, about 130 by 75 ftm in size; it is produced by small lophophoral organs, present only in members of burrowing or encrusting species (Phoronis ijimai, P.
    [Show full text]
  • The Crustacea
    TREATISE ON ZOOLOGY –ANATOMY,TAXONOMY,BIOLOGY THE CRUSTACEA COMPLEMENTARY TO THE VOLUMES TRANSLATED FROM THE FRENCH OF THE TRAITÉ DE ZOOLOGIE [Founded by P.-P. GRASSÉ (†)] Edited by F. R. SCHRAM and J. C. von VAUPEL KLEIN Advisory Editors M. CHARMANTIER-DAURES and J. FOREST VOLUME 9 PART B EUCARIDA: DECAPODA: ASTACIDEA P.P. (ENOPLOMETOPOIDEA, NEPHROPOIDEA), GLYPHEIDEA, AXIIDEA, GEBIIDEA, and ANOMURA With contributions by S. T. Ahyong, A. Asakura, J. S. Cobb, P. C. Dworschak, J. Factor, D. L. Felder, M. Jaini, D. Tshudy, C. C. Tudge, R. A. Wahle BRILL LEIDEN · BOSTON 2012 © 2012 Koninklijke Brill NV CONTENTS Preface .................................................................... 1 RICHARD A. WAHLE,DALE TSHUDY,J. STANLEY COBB,JAN FACTOR & MAHIMA JAINI, Infraorder Astacidea Latreille, 1802 p.p.: the marine clawed lobsters ................................................................. 3 PETER C. DWORSCHAK,DARRYL L. FELDER &CHRISTOPHER C. TUDGE, Infraorders Axiidea de Saint Laurent, 1979 and Gebiidea de Saint Laurent, 1979 (formerly known collectively as Thalassinidea) ............................. 109 CHRISTOPHER C. TUDGE,AKIRA ASAKURA &SHANE T. AHYONG, Infraorder Anomura MacLeay, 1838 ................................................. 221 List of contributors ......................................................... 335 Taxonomic index ........................................................... 339 Subject index .............................................................. 349 © 2012 Koninklijke Brill NV CHAPTER 69 INFRAORDERS AXIIDEA
    [Show full text]
  • Estimating the Early Evolution of Brachiopods Using an Integrated Approach Combining Genomics and Fossils
    Examensarbete vid Institutionen för geovetenskaper Degree Project at the Department of Earth Sciences ISSN 1650-6553 Nr 471 Estimating the Early Evolution of Brachiopods Using an Integrated Approach Combining Genomics and Fossils En uppskattning av armfotingarnas tidiga evolution – med hjälp av genomik och fossil Chloé Robert INSTITUTIONEN FÖR GEOVETENSKAPER DEPARTMENT OF EARTH SCIENCES Examensarbete vid Institutionen för geovetenskaper Degree Project at the Department of Earth Sciences ISSN 1650-6553 Nr 471 Estimating the Early Evolution of Brachiopods Using an Integrated Approach Combining Genomics and Fossils En uppskattning av armfotingarnas tidiga evolution – med hjälp av genomik och fossil Chloé Robert ISSN 1650-6553 Copyright © Chloé Robert Published at Department of Earth Sciences, Uppsala University (www.geo.uu.se), Uppsala, 2019 Abstract Estimating the Early Evolution of Brachiopods Using an Integrated Approach Combining Genomics and Fossils Chloé Robert The Brachiopoda, a major group of the Lophotrochozoa, experienced a rapid early evolutionary diversification during the well-known Cambrian explosion and subsequently dominated the Palaeozoic benthos with its diversity and abundance. Even though the phylogeny of the Lophotrochozoa is still hotly debated, it is now known that the Brachiopoda are a monophyletic grouping. However, the early evolutionary rates for the Brachiopoda have never been studied in the framework of a study combining molecular data and fossil time calibration points. In order to investigate the expected higher evolutionary rates of the Phylum at its origin, we conducted phylogenetic studies combining different methodologies and datasets. This work has at its foundation Maximum Likelihood and Bayesian analyses of 18S and 28S rRNA datasets followed by analyses of phylogenomic sequences.
    [Show full text]