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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Spirobolbolaimus

Spirobolbolaimus Soetaert & Vincx, 1988 (ref. ID; 1763 original paper)

ref. ID; 1763

Marine nematode. Anterior sensilla in three distinct crowns; external labial setae longer than cephalic sensilla. Amphideal fovea distinctly sclerotized, multispiral, ventrally wound, anterior position. Postamphideal setae in six rows. Pharynx with anterior bulbus and oval posterior bulbus. Copulatory apparatus strongly sclerotized. (ref. ID; 1763)
  1. Spirobolbolaimus bathyalis Soetaert & Vincx, 1988 (ref. ID; 1763 original paper)

Spirobolbolaimus bathyalis Soetaert & Vincx, 1988 (ref. ID; 1763 original paper)

Diagnosis

S. bathyalis is characterized by the multispiral amphideal fovea (4+3/4 turns, 55-65% of corresponding body diameter), lying partly on the non-annulated part of the head; the presence of numerous cells with an internal dense body in the cardial region; the heavily sclerotized spicules. (ref. ID; 1763)

Descriptions

Body cylindrical, slightly narrowing anteriorly, tapering posteriorly. Cuticle annulated (width of the annules 2 µm); each annule is convex, marking its margins well pronounced; a prominent interannular region is present; the annulation is less obvious in mid-body region. Somatic sensilla papilliform, in four submedian rows; epidermal glands associated with sensilla visible in some specimens. Head rounded; anterior part not annulated and broader than long. Internal labial sensilla papilliform; external labial setae (3-4 µm long, with a broad base) situated 2-4 µm behind the front end; cephalic papillae (less than 1 µm long, not always visible) situated 8-11 µm behind the front end. Amphideal fovea distinctly scleortized, multispiral, ventrally wound, 4+3/4 turns, 10-11 µm wide (55-65% of corresponding body diameter) its anterior broader lying on the non-annulated part of the head, 5-6 µm from the anterior end; posterior half of fovea surrounded by annules. Six rows of 2-6 setae (6-8 µm long) present posterior to the amphideal fovea: two ventrosublateral, two dorsosublateral rows, one mediodorsal and one medioventral row. Buccal cavity with one dorsal tooth; a pair of ventrosublateral teeth is situated posterior to the dorsal tooth, another pair of toothlike projections is anterior to the dorsal tooth; no denticles observed. Pharynx with anterior bulbus surrounding the buccal cavity and a terminal oval bulbus. Cardia 3-10 µm long. Intestine with distinct microvillous borders. Nerve ring at 53-54% of pharyngeal length. Ventral gland and pore not seen, but ventral invagination in anterior part of the intestine gives possible indication of the presence of the gland. In the cardial region are 20 to 30 cells, consisting each of an internal dense body surrounded by a clear region. Pseudocoelomocytes and other cells are abundant in the pharyngeal region. (ref. ID; 1763)
  • Male: Diorchic; testes outstretched and opposite; anterior testis left of the intestine, posterior one right of the intestine, less developed. Spermatozoa oval, elongated, up to 27 µm long, 6 µm wide. Two equal spicules, strongly sclerotized; a median, weakly sclerotized lamella present. Gubernaculum 10-11 µm long, plate-like. No precloacal supplements observed. (ref. ID; 1763)
  • Female: Didelphic, amphidelphic; ovaries outstretched; two prominent spermathecae present. Vulva a transverse slit, in posterior half a body. Vagina surrounded by a prominent sphincter; junction of vagina and vulva distally sclerotized, appearing as two refractive bodies in optical section. Tail gradually tapering; three caudal glands emptying together. Juveniles resembles the adults in all aspects, except the reproductive organs. (ref. ID; 1763)