Leptosomatum

 

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Rev: 02/21/2024

  Classification Biology and Ecology
Morphology and Anatomy Life Cycle
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Distribution Management
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Classification:

Enoplea
  Enoplia
        Enoplida
            Ironina
                Ironoidea
                     Leptosomatidae
Leptosomatinae

Leptosomatum  Bastian, 1865

    Type species of the genus: Leptosomatum elongatum Bastian, 1865 moved to Leptosomatides by Bongers (1993, 1994)

Synonyms:

Phanoglene Eberth, 1863

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Morphology and Anatomy:

  • Cephalic capsule weakly deveoped, apparent only in optical section.
  • Sexual dimorphism in structure of amphids. .
  • Pre- and postneural region of pharynx covered by numerous ganglia in both sexes. .
  • Stoma narrow, without onchia or odontia. Labial sensilla subcuticular, cephalic and cervical sensilla setiform or papilliform.
  • Dorsal pharyngeal gland orifice at level of amphids in pharyngeal lumen; orifices of ventrosublateral glands on anterior end; ducts cuticularized.
  • Ocelli present, provided with lens.
  • Caudal glands long; overlapping intestine.
  • Dorso- and ventrolateral orthometanemes present.
  Leptosomatum bacillatum A. Anterior of female; B: Anterior of male.
Drawings from Bongers, 1983

Male:

  • Somatic tissues atrophied

  • Renette and cervical pore absent

  • Amphids in males with enlarged fovea; amphidial glands strongly developed and outstretched over almost entire pharyngeal length

  • Ganglia of amphidial nerves much enlarged and situated at one body-diameter posterior to nerve ring

  •  Diorchic, testes opposed and outstretched.

  • Gubernaculum sumple.

  •  Precloacal ventromedian supplement reduced or absent; Subventral pre- and postcloacal genital sensilla absent.

Female:

  •  Renette and cervical pore present

  •  Female amphidelphic, antidromic.

 Ref: Bongers, 1983
 
Body size range for the species of this genus in the database - Click:
   


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Distribution:

Free-living marine nematodes.  Reported from coastal ocean waaters, including in association with sponges.  Many specimens have been collected from the sponge Halichondria panicea (Bongers, 1993).

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Feeding:

Epistrate feeders

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Biology and Ecology:

 

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Life Cycle:

Bongers (1993) observed that Leptosomatum bacillatum occurs in high densities in the sponge Halichondria panicea. His suggestion of  an annual reproductive cycle was supported by obsrvations from monthly samplings. Eggs are deposited in July and August and  L. bacillatum reaches maturity after one year. Mature females continue growing, their length being season dependent.

For Ecophysiological Parameters for this genus, click 

 

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Ecosystem Functions and Services:

 

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Management:

 
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References:

Bastian, H. Ch. 1865. Monograph on the Anguillilidae, or free Nematoids, marine, land, and freshwater; with descriptions of 100 new species.—Transactions of the Linnean Society of London 25:73-184.

Bongers, T.  1983. Revision of the genus Leptosomatum Bastian, 1865. Proc. Biol. Soc. Wash.  96:807-855.

Bongers, T. 1984. Revision of the genus Leptosomatides Filipjev, 1918 (Nematoda: Enoplida). Proc. Biol. Soc. Wash. 97: 12-29.

 Eberth, C. I. 1863. Untersuchungen über Nematoden.—Leipzig: W. Engelmann, pp. 1-77.

Filipjev, I. 1916. Free living nematodes in the collection of the Zoological Museum of the Imperial Academy of Sciences in Petrograd. - [Akademiya Nauk, Zoologicheskii Muzei, Ezhigodnik 21 : 59-116.] English translation, 1973, Smithsonian Institution and National Science Foundation, Washington, D.C., pp. 1-55.

Filipjev, I. 1918. Free-living marine nematodes of the Sebastopol area.-Trudy Osoboi Zoologicheskoi Laboratorii i Sebastopol'skoi Biologicheskoi Statsii Akademii Nauk (2)4:1-350.

Platonova, T. A. 1967. Free-living marine nematodes of the family Leptosomatidae from the European Arctic [Svobodnozhivushchie Morskie Nematody Semeistva Leptosomatidae Evropeiskoi Arktiki]. Zoologicheskii Zhurnal 46: 828-839.

Smol, N., Muthumbi, A., Sharma, J. 2014. Order Enoplida, 7.3. In Schmidt-Rhaesa, A. (ed) Handbook of Zoology. De Gruyter, Berlin

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Copyright © 1999 by Howard Ferris.
Revised: February 21, 2024.