Paratrichosoma		Contents		Rev: 02/23/2024
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Paratrichosoma Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Trichosomoididae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Classification:

Trichosomoididae (or Capillaridae)

Paratrichosoma Ashford and Muller, 1978

A nematode genus of parasites of the ventral scales of crocodiles

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Morphology and Anatomy:

• Long, slender nematodes, 2-7mm long, 0.082-0.167mm diam.

• Cuticle  unusually thick and smooth.

• Cloaca with a thick cuticular lining.

• Males lack  caudal papillae and a distinct lobe on the posterior end

• Male spicule well-developed spicule, which has a cover at the anterior.

• Stichosome present that does not reach reach the intestine

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• Morphologically, the two described Paratrichosoma species are quite similar except for:

  •  rough transverse grooves on the spicule of P. crocodylus but not on the spicule of P. recurvum

  • protruding polar plugs on the eggs of P. recurvum  but not on the eggs of P. crocodylus.

  • Mesenchynal cells at the esophago-intestinal junction are absent in P. crocodylus but present  in small amounts in P. recurvum,

  •  the posterior end of the ovary extends beyond the anterior end of the rectum in P. crocodylua but does not in P. recurvum

Ref: Lott, 2015; Ashford and Muller 1978, Moravec and Vargas-Vazquez 1997.

Paratrichosoma recurvum: A. Posterior end of a male with spicule and everted specular sheath; B. Spinose spicular sheath. C Stichocyte at the middle part of a stichosome; D. Mature egg in the uterus; E. Advanced egg containing a larva from a serpentine tunnel in the host's skin; F. Funnel-shaped everted spicular sheath of a male. Bars: A, D, E 20 um; B 50 um; C 10 um; F 30 um. From Moravec and Vargas-Vazquez, 1998

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Distribution:

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Feeding:

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Biology and Ecology:

Life-cycle of Paratrichosoma spp. is mainly speculative at the current time.  It has been suggested that the nematode colonizes the crocodile host; it has been suggested that infective larvae may be ingested with stones (gastroliths) which crocodilians consume for ballast; also, there may be an intermediate host which is exploited  by crocodiles as a food source. Another possibility is that freeliving larvae may burrow directly into the ventral skin of the crocodile althogh the thick skin may be a barrier to such penetration (Tellez and Paquet-Durand, 2011).

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Life Cycle:

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Ecosystem Functions and Services:

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Management:

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References:

Ashford, R. W., and R. Muller. 1978. Paratrichosoma crocodylus n. gen., n. sp. (Nematoda: Trichosomoididae) from the skin of the New Guinea crocodile. Journal of Helminthology 52:215�220.

Lott, M.J. 2015. Nematode community dynamics in Australian vertebrates: Impacts of contemporary captive management prectices. PhD Thesis, Macquarie University, Sydney, Australia..

Moravec, F., and J. Vargas-Vazquez. 1998. First description of the male and redescription of the female of Paratrichosoma recurvum (Nematoda: Capillariidae), a skin-invading parasite of crocodiles in Mexico. Parasitology Research 84:499�504.

Solger, B. 1877. Ueber eine neue Spezies von Trichosoma. Archiv fur Naturgeschichte 43:19�23.

Solger, B. 1933. Ein vergessener Parasit (Trichosoma recurvum) als Ursache von  "creeping disease"; ein literar-hitorischer Beitrag zur vergleichenden Pathologie der Haut der Wirbeltiere. Dermatologische Wochenshrift 96:476-477

Tellez, M. and Paquet-Durand, I. 2011.  Nematode Infection of the Ventral Scales of the American Crocodile (Crocodylus acutus) and Morelet's Crocodile (Crocodylus moreletii) in Southern Beliz Comparative Parasitology 78:378-381.

Copyright © 1999 by Howard Ferris.
Revised: February 23, 2024.