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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Cobbionema

Cobbionema Filipjev, 1922 (ref. ID; 3571)

Chromadorida Filipjev, 1929: Family Choniolaimidae Stekhoven & Adam, 1931 (ref. ID; 3571)

Family Selachinematidae (ref. ID; 6976)

ref. ID; 3571

Type species

Cobbionema acrocerca Filipjev, 1922 (ref. ID; 3571)
  1. Cobbionema acrocerca Filipjev, 1922 (ref. ID; 3571)
  2. Cobbionema capense Furstenberg & Heyns, 1987 (ref. ID; 6976 original paper)
  3. Cobbionema cylindrilaimoides Stekhoven, 1950 (ref. ID; 3571), Schuurmans Stekhoven, 1950 (ref. ID; 6976)

Cobbionema capense Furstenberg & Heyns, 1987 (ref. ID; 6976 original paper)

Diagnosis

Cobbionema capense n. sp. is distinguished from the type species C. acrocerca and from C. cylindrilaimoides by the moderately cuticularized posterior chamber of the buccal cavity and teeth ridges. (ref. ID; 6976)

Descriptions

The lip region is 19.7 µm wide with the normal complement of labial papillae. Ten cephalic setae are present; there is an anterior crown of 4 short setae, 3.5 µm long, as opposed to the posterior crown of 6 long labial setae, 6.5 µm long. Somatic setae are scarce. Only 3 somatic setae can be observed, i.e., 2 at the tail, subdorsally, and 1 dorsal setae near the pharyngeal bulbus. All three are 3.6 µm long. Two pairs of inconspicuous caudal pores, subventral and just posterior to the anus, are present. The cuticle has inconspicuous rows of punctations distributed homogeneously over the entire body. No lateral differentiation was visible. The amphid is multispiral, 6.8 µm wide and 11.3 µm from anterior end. The stoma is complicated as is typical of the family Selachinematidae. The stoma consists of a wider, cylindrical portion, 7.8 µm wide and 8.2 µm long, and 2.7 µm wide at its base. The 2 chambers are roughly separated by a series of smallish teeth and denticles. The walls of both chambers are cuticularized. Rugae strengthen the wall of the posterior chamber. The entire anterior chamber and, possibly a small portion of the posterior chamber are surrounded by a sphincter enclosing both the wall of the chamber and the rugae. The sphincter begins 3.3 µm from the anterior end and is 18.0 µm wide and 7.6 µm thick. The stoma bears 2 groups of hollow teeth and 4 groups of denticles that are situated as follows. Two smallish teeth are located subventrally; they are connected by a ridge. Near this ridge, in a ventro-median position, is a solitary, anteriorly directed, smallish tooth. Subdorsally there is a group of about 4 smallish teeth, which are posteriorly directed. Two of these form a ridge similar to the one found between the subventral teeth. The denticles are arranged in 4 groups, 2 of which are situated laterally, while the other 2 are in a subventral position, but closer together than the two subventral teeth. A muscular, anterior, pharyngeal bulbus, typical this family, 30 µm long and 20.5 µm wide at its widest part, is followed by an isthmal attenuation, 15.5 µm wide. The posterior third of the pharynx gradually enlarges to a pear-shaped base. No pharyngo-intestinal valve can be seen. Excretory pore, excretory duct, and renette cell are not visible. Interstinal wall with numerous refractive granules. A male Chromadorid specimen fills the whole intestine. Rectum 11.7 µm long. Tail conoid with an elongate portion two-thirds of total tail length. Two of three caudal glands distinct, leading to a spinneret. Vulva transverse, leading to a small, weakly muscularized vagina, 9.8 µm long, 7.1 µm wide. Ovaries paired, equal, opposed, and reflexed. Anterior ovary slightly distorted, situated on the right hand side of the intestine, posterior ovary one the left. (ref. ID; 6976)
  • Male: No males present. (ref. ID; 6976)

    Type locality and habitat

    In the intertidal grey-black muddy bottom, 6 km from the mouth in the middle reaches of the Swartkops estuary, Port Elizabeth, 35 degrees 57'S and 25 degrees 37'E, collected 8 May 1979 by J.P. Furstenberg. (ref. ID; 6976)

    Type slide

    Holotype female on slide 7B/89 in the collection of the Department of Zoology, University of Port Elizabeth. (ref. ID; 6976)

    Measurements

    Holotype female: L=688 µm; a=14.3; b=6.6; c=6.9, V=43.0; G1=12.7; G2=14.8; body width 48 µm; anal body width 30.0 µm; length of pharynx 113 µm; length of tail 91.2 µm; rectum 11.7 µm; the 6 external (posterior) labial setae are 6 µm long; the 4 cephalic setae are 3.5 µm long. (ref. ID; 6976)