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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Kenyanema

Kenyanema W. Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)

ref. ID; 1902

Comesomatidae. Body is cylindrical; head region much narrower than the rest of the body; cuticle punctated and sometimes annules are clearly visible; inner and outer labial sensilla indistinct four cephalic sensilla setiform amphids spiral with 1.5-2 turns; stoma is tubular without teeth; male reproductive system monorchic with outstretched anterior branch. Females amphidelphic with outstretched ovaries. Spicules massive and curved; gubernaculum with a long caudal apophysis. Jensen (1978) re-arranged the family Comesomatidae into three subfamilies Sabatieriinae, Dorylaimopsinae and Comesomatinae on the basis of the buccal cavity, structure of the copulatory apparatus, and the arrangement of the cephalic sensilla. On the basis of the stoma (Jensen 1979) and the copulatory apparatus (Platt 1985) Kenyanema is close the to genera in the subfamily Dorylaimopsinae. The sub family (Dorylaimopsinae) is composed of genera characterised by a tubular stoma with teeth (e.g. Dorylaimopsis) or without armament (e.g. Metasabatieria). The copulatory apparatus is also typical for the subfamily, strong curved spicules and gubernaculum with a dorsal apophysis. The new genus differs from the rest of the genera however, in that only the cephalic sensilla are distinct; it is also the only described species in Comesomatidae with single branch in the male reproductive system. Muthumbi et al. (1997), however, place Kenyanema gen. n. in the subfamily Dorylaimopsinae until more material are found to place it otherwise. This genus named after Kenya. (ref. ID; 1902)
  1. Kenyanema monorchis W. Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)

Kenyanema monorchis W. Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)

Diagnosis

Kenyanema monorchis gen. et sp. n. is the only Comesomatid so far described with a single testis. It has a head region that is narrower than the rest of the body; labial sensilla not distinct; four cephalic sensilla obvious but short (3 µm); amphids with 2 turns and located at the level of the cephalic setae distinct pharyngeal tubules; males have large elongate spermatids; spicules are massive and ventrally curved and they have a short central lamina. The gubernaculum has a long, thin caudal apophysis with a sharp posterior tip; the tail is short conico-cylindrical, swollen tip with two terminal setae. (ref. ID; 1902)

Descriptions

Marine species. (ref. ID; 1902)
  • Female: Females are similar to males in general body shape, anterior sensilla, cuticle and the stoma. The reproductive system is amphidelphic with outstretched branches. The anterior branch is to the left and the posterior branch is to the right of the intestine. The ovary is short and the mature ovum may occupy upto one third of the length. (ref. ID; 1902)
  • Male: The body is cylindrical, with narrowing anterior part (5-7 µm) and conical tail with swollen tip. The cuticle is annulated and punctated on the median layer. The annules begin halfway the amphideal region. The annules are more pronounced at the pharyngeal (nine annules per 10 µm) and at the tail (six annules per 10 µm) than at the mid body. Laterally, the punctations are larger and more widely spaced. Somatic setae are scarce and short. The inner and outer labial sensilla are indistinct (only being visible under the SEM) and the cephalic sensilla are 3 µm long. The amphids are spiral with two turns, 4-6 µm diameter (63-75% corresponding body diameter) and located at the level of the cephalic setae. The stoma is tubular, 6-8 µm long and 2 µm wide and surrounded by the pharyngeal muscles. The pharynx is cylindrical. The marginal tubes begin from the base of the stoma. The nerve ring is located at 27-39% of the pharyngeal length from the anterior and the opening of the ventral gland is located posterior of the nerve ring at 44-55% of the length of the pharynx from the anterior. The ventral gland cell body was not seen. Carida is small but distinct. The reproductive system is monorchic with a short. outstretched anterior testis located to the left of the intestine. The sperm cells are large, elongate to round in shape. The developing spermatozoids are large and have a large nucleus. The spicules are 1.4-1.7 anal body diameter long, strongly curved and they have a short central lamina. They are surrounded by glandular tissue especially at the posterior end. The gubernaculum is strong and it has a long (12-17 µm) caudal apopysis. Tail is conical (81-100 µm long and tail length divided by anal body diameter=3.1-4.5) with a short (1/3 tail length) cylindrical part and a swollen tip with three terminal setae. The caudal glands open through three separate outlets. (ref. ID; 1902)

    Etymology

    The species name is derived from the word monorchic which means single testis. (ref. ID; 1902)