Crassicauda

Crassicauda	Contents	Rev: 01/20/2025
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Crassicauda 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

Crassicauda Leiper & Atkinson, 1914

Type species of the genus: Crassicauda crassicauda Leiper & Atkinson, 1914

Synonyms:

Filaria crassicauda Creplin, 1829

Morphology and Anatomy:

Very large nematodes; although difficult to separatew fro host tissues, body fragments up to 3.7 m long have been measured.

The genus differs from Placentonema (also a parasite of sperm whales) lacking caudal alae w in the male and lacking multiple branchung of the reproductive tract in the female.

Characteristics of Crassicauda magna as an example of the genus:

Anterior end bluntly rounded; oral opening bilobed, laterally compressed in apical view; surrounded by cuticular plate (ptilina); large lateral rounded papillae (pseudolabia) projecting beyond anterior margins of head, merging posteriorly into cuticular plate, possibly bearing three papillae (2 cephalic papillae and amphid); lateral margins of cuticular plate with irregular projections, larger projections lateral, bearing prominent but fine transverse striations.
Buccal capsule 200 um long, 90 um wide; walls parallel, sclerotized, 10 um thick.
Deirids 0.40 mm from anterior end; excretory pore 0.55 mm from anterior end; nerve ring 0.50 mm from anterior end;
Muscular esophagus 2.25 mm long.

Females:

Males:

Tail coiled tightly in 2 complete coils; terminating bluntly
Cloaca subterminal, with phasmids posterior to cloaca; 2 lateral expansions of cuticle present anterior to cloaca with irregularly arranged superficial striations; single median precloacal papilla present with paired neural terminations; 5 pairs of sessile lateral papillae, extending anteriorly from median pre-cloacal papilla, each with single neural termination; cuticle between columns of lateral papillae with parallel transverse striations.
Left spicule robust, about 2 mm long and twice as long as right spicicule; heavily sclerotized; anterior extremity enlarged; distal extremity blunt, distinctly narrowed, with transparent flange visible only in ventral views.
Ref: Jabbar et al., 2015

Body size range for the species of this genus in the database - Click:

Note: a recent phylogeny study places Crassicauda within a clade comprised of members of the family Acuariidae and the superfamily Acuarioidea. All morphological classifications have included Crassicauda and the subfamily Crassicaudinae in the family Tetrameridae and the superfamily Habronematoidea. The Acuarioidea are differentiated from the Habronematoidea by the possession of cuticular ornamentation in the form of cordons, collarettes or ptilina derived from anterior cuticular structures. Further studies will be necessary to determine the phylogeny of the genus.(Jabbar et a;., 2015)

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Distribution:

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Feeding:

Parasites of the body tissues of whales and dolphins (Cetacea) (Delyamure 1955). Particulary described as parasites of the neck muscles of the pygmy sperm whale, Kogia breviceps.

Nematodes of the genus Crassicauda infect the vasculature, urogenital system, muscles, mammary glands, and cranial sinuses of cetaceans, including both mysticetes and odontocetes (Balbuena and Simpkin, 2014; Dailey, 1985_

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Biology and Ecology:

The nematodes of this genus are very large and usually embedded in muscle tissiues, so it is difficult to obtain intact speimens for accurate morphometric measurements

Crassicauda magna in the subcutaneous tissues of adult female pygmy sperm whale beached in Moreton Bay, Queensland, Australia (courtesy of Mike Carr, the Marine Park Ranger at the Moreton Bay Marine Parks, Queensland Parks & Wildlife, Service, Australia); photograph from Jabbar et al., 2015

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Life Cycle:

As marine spirurids typically require intermediate hosts, transmission via intermediate hosts involved in the diet (e.g., crustaceans, cephalopods, fishes) has been speculated (Anderson, 2000). For those species of Crassicauda that infect the mammary glands of smaller odontocetes, the presence of adult nematodes and nematode ova observed in the mammary glands, suggests the possibility of direct transmission from mother to offspring via contaminated milk (Kot et al., 2022).

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:

Anderson R.C. 2000. Nematode Parasites of Vertebrates: Their Development and Transmission. CABI Publishing; Wallingford, UK:

Balbuena J.A., Simpkin A. 2014. Role of Crassicauda sp. in natural mortality of pantropical spotted dolphins Stenella attenuata: a reassessment. Dis. Aquat. Org. 108:83â€“89. doi: 10.3354/dao02694.

Creplin, F.C.H. 1829. [Descriptions of new species of Filaria and Monostomum found in " Balaena rostrata "], Verh. d. K. Leop.- Carol. Ak. d. Naturf (Bonn), xiv. 2 Abth. pp. 871-882, pl. lii.

Dailey M.D. 1985. Diseases Of Marine Animals. Volume IV, Part 2. Kinne O. (ED). Biologische Anstalt Helgoland; Hamburg: 1985. Diseases of mammalia: cetacean; pp. 805â€“847.

Jabbar, A., Beveridge, I., Bryant, M.S. 2015. Morphological and molecular observations on the status of Crassicauda magna, a parasite of the subcutaneous tissues of the pygmy sperm whale, with a re-evaluation of the systematic relationships of the genus Crassicauda. Parasitol Res. 114:835-884.

Kot, B., Ho, .N., Leung, V., Chung, T.., Tsui, H. 2022. Characterisation of Crassicauda fuelleborni nematode infection in Indo-Pacific finless porpoises (Neophocaena phocaenoides) using postmortem computed tomography. Int. J. Parasitol. Parasites Wildlife 18:68-65