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Hessler RR, Elofsson R. The reproductive system of Derocheilocaris typica (Crustacea, Mystacocarida). Arthropod Struct Dev 2012; 41:281-291. [PMID: 22406764 DOI: 10.1016/j.asd.2012.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/23/2012] [Accepted: 02/24/2012] [Indexed: 05/31/2023]
Abstract
Mystacocarids are dioecious. Their gonopores are on the medial side of the third thoracic limb. The male's paired testes lie in the thorax and abdomen. They develop from paired rows of six small follicles dorsally. In the mature animal they fill most of the abdomen. The spermatophores develop within the follicles from spermatogonia mixed with follicle cells, which support and nourish the spermatocytes and produce the seminal fluid. The short vas deferens runs along the bottom of the testes and then continues forward to the gonopore. The vas deferens has a small group of cells near the gonopore that becomes a closure mechanism. The female has reproductive cells and also support cells that provide nutrition and form the wall of the ovary and oviduct. The unpaired female ovary begins in the third thoracic segment. During maturation, the oocytes are pushed posteriorly. The enormous mature ovum extends into a caudal pocket of the ovary. Starting with its anterior end, this ovum is extruded into the short oviduct, which extends laterally and ventrally to the gonopore. During extrusion, the pocket is reabsorbed from behind. There are no accessory structures connected to the reproductive system, nor any external specializations on the third limb.
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Affiliation(s)
- Robert R Hessler
- Scripps Institution of Oceanography, University of California, La Jolla, 92093-0202, USA.
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Elofsson R, Hessler RR. The intestinal musculature of Derocheilocaris typica (Crustacea, Mystacocarida)--a different and unique pattern. Arthropod Struct Dev 2010; 39:242-250. [PMID: 20114088 DOI: 10.1016/j.asd.2010.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 01/06/2010] [Accepted: 01/07/2010] [Indexed: 05/28/2023]
Abstract
An ultrastructural study of the intestine of Derocheilocaris typica revealed an organization of the midgut musculature, which is unique in the Crustacea. This species unusual anal skeletomusculature has also not been seen before. The intestinal musculature of D. typica displays different patterns in the fore-, mid-, and hindgut. Around the foregut, eight pairs of dilator muscles complement a contiguous carpet of circular muscles around the foregut. Their coordinated action serves to suck in food and pass it to the midgut. A pair of large glands, each consisting of three cells, opens into the foregut above the mouth. The midgut musculature differs from any previously described. Circular muscles give rise to thin, longitudinal protrusions and short longitudinal muscles. The distribution of all of them is irregular. Thus the short longitudinal muscles, which have a length of approximately one segment, vary from none to five within a segment. The last abdominal segment is exceptional, by having 15-20 short longitudinal muscles. The hindgut has three longitudinal muscle groups each consisting of three muscles, one dorsally and one on each side. The posterior end of the midgut and the hindgut suggests that they act together to achieve defecation. The importance of the peri-intestinal cells as part of the nutritional process is emphasized.
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Affiliation(s)
- Rolf Elofsson
- Department of Cell and Organism Biology, Helgonavägen 3, University of Lund, SE-22362 Lund, Sweden.
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Elofsson R, Hessler RR. Two microvillar organs, new to Crustacea, in the Mystacocarida. Arthropod Struct Dev 2008; 37:522-534. [PMID: 18590833 DOI: 10.1016/j.asd.2008.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 05/23/2008] [Accepted: 05/24/2008] [Indexed: 05/26/2023]
Abstract
The mystacocarid crustacean Derocheilocaris typica has two microvillar organs, one new, the other previously unappreciated in crustacean literature. The first is situated on the head-shield and consists of three pairs of cells: one with microvilli and a ballooned nucleus; one smaller and without special features; the third large and investing the other two and extending down to the foregut. We call this new organ the "cephalic microvillar organ" and discuss the value of the concept "dorsal organ", to which it might have been included. The second organ consists of about 21 cells that cover the proximal part of the dorsal surface of the labrum. The cells are alike, being characterized by an apical field of microvilli and a large residual body. This organ is here called the "labral microvillar organ". Both organs are neither sensory nor secretory and do not qualify for membership in any of the other recognized organ systems. We are unable to deduce their Dero-cheilocaris functions.
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Affiliation(s)
- Rolf Elofsson
- Department of Cell and Organism Biology, Zoology Building, University of Lund, Helgonavägen 3, SE-223 62 Lund, Sweden.
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Levin LA, Etter RJ, Rex MA, Gooday AJ, Smith CR, Pineda J, Stuart CT, Hessler RR, Pawson D. Environmental Influences on Regional Deep-Sea Species Diversity. ACTA ACUST UNITED AC 2001. [DOI: 10.1146/annurev.ecolsys.32.081501.114002] [Citation(s) in RCA: 522] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lisa A. Levin
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - Ron J. Etter
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - Michael A. Rex
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - Andrew J. Gooday
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - Craig R. Smith
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - Jesús Pineda
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - Carol T. Stuart
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - Robert R. Hessler
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
| | - David Pawson
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093-0218; e-mail:
- Department of Biology, University of Massachusetts, Boston, Massachusetts 02125; e-mail:
- Southampton Oceanography Centre, European Way, Southampton SO14 3ZH United Kingdom; e-mail:
- Department of Oceanography, University of Hawaii, Honolulu, Hawaii 96822; e-mail:
- Department of Biology, MS 34, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; e-mail:
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Read AT, Hessler RR, Govind CK. Muscle and Nerve Terminal Fine Structure of a Primitive Crustacean, the Cephalocarid Hutchinsoniella macracantha. Biol Bull 1994; 187:16-22. [PMID: 29281310 DOI: 10.2307/1542161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Abdominal muscles of the cephalocarid Hutchinsoniella macracantha resemble the striated muscle fibers of other crustaceans, having regularly aligned sarcomeres that average 5 μm in length; thick, wavy Z-lines; and orbits of eight thin filaments surrounding a thick filament. However, unlike most crustacean muscle fibers, the cephalocarid muscle fibers are not subdivided into myofibrils by elaboration of the longitudinally oriented sarcoplasmic reticulum. Consequently, elements of the transverse tubule and sarcoplasmic reticulum in the form of triads occur scattered over the entire fiber. Motor innervation is by means of scattered nerve terminals, populated with round synaptic vesicles, indicative of excitatory axons. By lacking myofibrils, the cephalocarid and ostracod muscle represents a much simpler condition than the myofibril-rich muscles of the other crustacean classes and signifies a primitive condition in its resemblance to the onycophoran muscle.
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