Placentonema		Contents		Rev: 01/29/2025
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Placentonema Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Tetrameridae Menu		Feeding		References
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Classification:

Chromadorea

  Chromadoria

   Rhabditida

Spirurina

              Habronematoidea

               Tetrameridae

  Crassicaudinae

Placentonema Gubanov, 1951

Type species of the genus: Placentonema gigantissima Gubanov, 1951

Parasite of the placenta of sperm whales

    Synonyms:
     

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Morphology and Anatomy:

Very large nematodes; females >8 meter length

The genus differs from Crassicauda in the type (and only) species having caudal alae with stub-like papillae in the male and,  in the female, with multiple branchung of the reproductive tract into 32 uteri.

Placentonema gigantissima - original description from Gubanov, 1951 Source Wikipedia, accessed January 19, 2025	Placentonema gigantissima - Gubanov, 1951 paper translated to English Source Wikipedia, accessed January 19, 2025

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Distribution:

Sperm whale (Physeter carodon) hosts in the lower latitudes of the southern hemisphere.

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Feeding:

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Biology and Ecology:

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Life Cycle:

Although the life cycle and longevity of P. gigantissima are not well known and would be difficult to study, it seems reasonable to assume direct transmission of larval nematodes via the placenta into the developing whale calf before birth.  Further, the existence of larval nematodes in and around the mammary glands of the nursing mother suggest another likely avenue of direct transmission.

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Ecosystem Functions and Services:

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Management:

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References:

Delyamure, S.L. 1955. Helminthofauna of marine mammals (Ecology and Phylogeny). Gel'mintologicheskaya Laboratoria, Akademiya Nauk SSSR, Moskva. English translation: Israel Program for Scientific Translations, Jerusalem, 1968 pp 520.

Gubanov, N.M.  A giant nematode from the placenta of cetaceans; Placenttnema gigantissima n.g. n.sp. Doklady Akademii Nauk SSSR. 77(6): 1123-1125.

Hermosilla, C., Hirzmann, J.; Silva, L. M.R.; Brotons, J M.; Cerda, M.; Prenger-Berninghoff, E.; Ewers, C.; Taubert, A. 2018.  Occurrence of anthropozoonotic parasitic infections and faecal microbes in free-ranging sperm whales (Physeter macrocephalus) from the Mediterranean Sea. Parasitology Research 117: 2531-2541. doi:10.1007/s00436-018-5942-3

Copyright 1999 by Howard Ferris.
Revised: January 29, 2025.