Oculotrema hippopotami

Oculotrema hippopotami
Systematics
Trunk :	Flatworms (Plathelminthes)
Class :	Hook worms (Monogenea)
Subclass :	Polyopisthocotylea
Family :	Polystomatidae
Genre :	Oculotrema
Type :	Oculotrema hippopotami
Scientific name of the genus
	Oculotrema
	Stunkard, 1924
Scientific name of the species
	Oculotrema hippopotami
	Stunkard , 1924

Oculotrema hippopotami is a parasitic species of the Monogenea within the flatworms (platelets). The worm, which is between 12 and 32 millimeters long, lives ectoparasitic exclusively on the eyes of the hippopotamus ( Hippopotamus amphibius ) and is therefore the only type of monogenea thathas been detectedin a mammal .

features

Oculotrema hippopotami is a dorsoventrally flattened worm with a body length between 12 and 32 millimeters, an average of 17 millimeters, and a width of 2 to 3 millimeters. This makes it one of the largest known monogenes. The rear end is rounded and the front end extended. The mouth opening is subterminal; it is surrounded by muscles, but has no mouth capsule. The back two thirds of the adult body is bright red, the color coming from the parenchyma ; frozen animals change color to olive green. Non-adult worms are white. The reproductive organs are located in the last third of the body. Due to the flexible fabric, the animals are able to stretch out and extend their length to twice their body length. Hemoglobin was detected as a blood pigment in the animals .

Way of life

Oculotrema hippopotami lives as an ectoparasite exclusively on the eyes of the hippopotamus ( Hippopotamus amphibius ), where it is mainly in the conjunctiva and sclera as well as under the eyelids and on the nictitating membrane , rarely on the cornea . The animals are often found in clusters with the suction cups close together. The attachment is very strong, making it difficult to detach the animals from the eye. Thurston & Laws (1965) determined an infection rate of more than 70% in killed hippos in western Uganda. They examined more than 1200 individuals, of which they were able to detect the parasite in 960. Du Preez & Moeng (2004) even found an infection rate of 90% in KwaZulu-Natal , South Africa , with 75% carrying the parasites in both eyes. They found a maximum of 24 parasites on one eye and 37 parasites on one individual.

Unlike other types of monogenea, Oculotrema hippopotami does not feed on blood, but probably only on tear fluid and expelled epidermal cells . Like most Monogenea, Oculotrema hippopotami has a reproductive cycle without changing hosts . The eggs are very thick-skinned compared to other monogenes, which is seen as an adaptation to the way of life under the eyelids.

Systematics

The first scientific description of Oculotrema hippopotami came from the American parasitologist Horace W. Stunkard in 1924. He described the species on the basis of five museum specimens from the Cairo museum , which probably came from a hippopotamus living in the Giza Zoo in Cairo. Due to the special features he described, in particular the origin of a mammal, the description was partially not accepted in a scientific context and was referred to in a standard work in 1952 as an incorrectly labeled individual or a chance infection. It was not until 1965 that the species was described again by Thurston & Laws. They were able to detect the species in western Uganda, with over 70% of the examined hippos from a population on Lake Edward being infected by the parasite.

The species is assigned to the Monogenea and therein to the Polystomatidae . It is the only type of monogenea that has been detected in a mammal .

supporting documents

↑ ^a ^b ^c ^d ^e Louis H. du Preez, Itumeleng A. Moeng: Additional morphological information on Oculotrema hippopotami Stunkard, 1924 (Monogenea: Polystomatidae) parasitic on the African hippopotamus. African Zoology 39 (2), 2004: pp. 225-233.
↑ JP Thurston: Hemoglobin in a Monogenean, Oculotrema hippopotami. Nature 228, 1970: p. 578.
↑ ^a ^b J.P. Thurston, RM Laws: Oculotrema hippopotami (Trematoda: Monogenea) in Uganda. Nature 205, 1970: p. 1127.
↑ HW Stunkard: A new trematode, Oculotrema hippopotami ng, n.sp., from the eye of the hippopotamus. Parasitology 16, 1924: pp. 436-441.

[du_Preez_&_Moeng_2004-1] Louis H. du Preez, Itumeleng A. Moeng: Additional morphological information on Oculotrema hippopotami Stunkard, 1924 (Monogenea: Polystomatidae) parasitic on the African hippopotamus. African Zoology 39 (2), 2004: pp. 225-233.

[Thurston_1970-2] JP Thurston: Hemoglobin in a Monogenean, Oculotrema hippopotami. Nature 228, 1970: p. 578.

[Thurston_&_Laws_1965-3] J.P. Thurston, RM Laws: Oculotrema hippopotami (Trematoda: Monogenea) in Uganda. Nature 205, 1970: p. 1127.

[Stunkard_1924-4] HW Stunkard: A new trematode, Oculotrema hippopotami ng, n.sp., from the eye of the hippopotamus. Parasitology 16, 1924: pp. 436-441.