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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Dorylaimopsis

Dorylaimopsis Ditlevsen, 1918 (ref. ID; 3571)

Chromadorida Filipjev, 1929: Family Comesomatidae Filipjev, 1918: Subfamily Dorylaimopsinae De Coninck, 1965 (ref. ID; 3571)

ref. ID; 3571

Type species

Dorylaimopsis punctata Ditlevsen, 1918 (ref. ID; 3571)
  1. Dorylaimopsis brevisetosa (subsp.) Timm, 1952
    See; Dorylaimopsis metatypica subsp. brevisetosa (ref. ID; 3571)
  2. Dorylaimopsis coomansi Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)
  3. Dorylaimopsis euryonchus (Wieser, 1954) (ref. ID; 3571)
    Syn; Xinema euryonchus Wieser, 1954 (ref. ID; 3571)
  4. Dorylaimopsis gerardi Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)
  5. Dorylaimopsis mediterranea Grimaldi-De Zio, 1968 (ref. ID; 3571)
  6. Dorylaimopsis mediterraneus Grimaldi de Zio, 1968 (ref. ID; 1902)
  7. Dorylaimopsis metatypica Chitwood, 1936 (ref. ID; 3571)
  8. Dorylaimopsis metatypica subsp. brevisetosa Timm, 1952 (ref. ID; 3571)
  9. Dorylaimopsis peculiaris Platonova, 1971 (ref. ID; 3571)
  10. Dorylaimopsis perfecta (Cobb, 1920) Filipjev, 1934 (ref. ID; 3571)
    Syn; Xinema perfectum Cobb, 1920 (ref. ID; 3571)
  11. Dorylaimopsis punctata Ditlevsen, 1918 (ref. ID; 3571)
  12. Dorylaimopsis rabalaisi Zhang, 1992 (ref. ID; 1902)
  13. Dorylaimopsis turneri Zhang, 1992 (ref. ID; 1902)
  14. Dorylaimopsis variabilis Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)

Dorylaimopsis coomansi Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)

Diagnosis

Dorylaimopsis coomansi sp. n. is characterised by long (8-10 µm) cephalic setae, cuticular punctation which has lateral differentiation of irregularly arranged dots at the pharyngeal and tail regions and 1-3 longitudinal rows of dots on the rest of the body. The spicules have a capitulum and they are hooked at the proximal end; the gubernaculum apophysis has a blunt tip. D. coomansi sp. n. differs from all other described species in the spicule and gubernaculum shape. The cuticular punctation is similar to that of D. turneri Zhang, 1992 but in D. turneri there are five longitudinal rows of dots posterior of the pharyngeal region. (ref. ID; 1902)

Descriptions

Marine species. (ref. ID; 1902)
  • Female: The females are similar to the males in general body shape, anterior sensilla and cuticle. The reproductive system is amphidelphic, with outstretched ovaries. There is however, one female which has its anterior ovary reflexed at the tip. Each branch has a short uterus, a small spermatheca and a long ovary. The vulva is simple and vagina has thick walls. The tail is similar to that of the male but it is slightly longer 142-157 µm (tail length divided by anal body diameter 3.6-4.1) and lacks the numerous setae. (ref. ID; 1902)
  • Male: The body is cylindrical; anteriorly with blunt end and with a conico-cylindrical tail. The cuticle is punctated. Punctations begin at the level of the anterior border of the amphids. Laterally, the punctations are larger and more widely spaced; on the pharyngeal and the region (including the region at the level of the spicules), the punctations are irregularly arranged and on the rest of the body. The differentiated part is raised and may have one, two or three longitudinal rows of dots which may be regularly or irregularly arranged. The differentiated lateral region at the mid body is 4-6 µm. There are eight rows of long (7 µm) somatic setae which may be more conspicuous at the pharyngeal region than on the rest of the body. The inner labial sensilla are indistinct, outer labial are papilliform and the cephalic ones are long (8-10 µm) setiform (67-81% head diameter at the level of the cephalic setae). The amphids are spiral with 2.5 turns and located immediately posterior of the cephalic sensilla; they are 8-9 µm in diameter (53-64% corresponding body diameter). Stoma is tubular (19-20 µm) with three large teeth in the anterior part and highly sclerotised walls in the posterior part. The dorsal pharyngeal gland opens at the base of the stoma where the radial tubules also begin. The pharynx is long (180-195 µm) cylindrical with an expanded base to form the terminal bulb, 22-34 µm at the widest diameter (corresponding body diameter is 38-47 µm). The nerve ring is located at 46-53% of pharyngeal length from the anterior. The opening of the ventral gland is located posterior of the nerve ring at 54-57% of the pharyngeal length from the anterior (corresponding body diameter is 31-39 µm). The cardia is small. The intestinal wall has glandular cells; more numerous close to the cardia and less so more posteriorly. The reproductive system is diorchic, with opposed and outstretched testes. The anterior branched is to the right and the posterior branch is to the left of the intestine. The spermatozoa are small and tightly packed in the testes. The spicules are 1.4 and 1.7 anal body diameter long and curved; they have a capitulum and their proximal tip is sharp and hooked. There are 16 fine precloacal supplements extending up to 166 µm anterior of the cloaca. Close to the cloaca, the supplements are close together (a 47 µm section has nine supplements), further away from the cloaca the supplements are 12-20 µm apart. The gubernaculum has a long (26 and 34 µm) dorso-caudal apophysis which is blunt and rounded at the tip. The tail is long (130 and 135 µm), conico-cylindrical with numerous setae at the ventral and subventral region (tail length divided by anal body diameter 3.2 and 3.4). There are three long terminal setae. The caudal glands open through a prominent spinneret. (ref. ID; 1902)

    Etymology

    The species name is given in honour of Prof. A. Coomans (Director of the Zoology Institute, University of Ghent). (ref. ID; 1902)

    Dorylaimopsis gerardi Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)

    Diagnosis

    Dorylaimopsis gerardi sp. n. is characterised by short setiform labial and long (6-7 µm) cephalic sensilla (38-43% head diameter at the level of the cephalic setae); punctated cuticle with irregularly arranged dots at first then three or four irregularly arranged longitudinal rows at the pharyngeal and tail regions, and two regularly arranged longitudinal rows of dots on the rest of the body length; the tail is conico-cylindrical with a distinctly swollen tip. D. gerardi sp. n. resembles D. rabalaisi Zhang, 1992 in the pattern of cuticular punctations but it can be distinguished from it by the length of the cephalic sensilla (54-83% head diameter at the level of the cephalic setae in D. rabalaisi), the diameter of the amphideal fovea (57-79%) and the shape of the spicules. (ref. ID; 1902)

    Descriptions

    Marine species. (ref. ID; 1902)
  • Female: The females are similar to the males in general body shape, anterior sensilla, cuticle and the tail. The reproductive system is amphidelphic with outstretched ovaries. (ref. ID; 1902)
  • Male: The general body shape is cylindrical with blunt anterior end and a narrow conico-cylindrical posterior end. The head region is slightly constricted thereby appearing to be offset. The cuticle is punctated with punctations starting at the anterior border of the amphids. Laterally, the punctations are larger, more widely spaced and irregularly arranged close to the amphids and in three or four irregularly arranged longitudinal rows on the rest of the pharyngeal region and upto 40-115 µm behind it. On the rest of the body, there are two regularly arranged longitudinal rows of dots while on the tail the arrangement is similar to that of the pharyngeal region. On the dorsal and ventral sides the punctations are smaller and arranged in transverse rows. There are eight longitudinal rows of somatic setae 3-4 µm long. All three circles of the anterior sensilla are distinct; the inner and outer labial sensilla are short setiform; the cephalic ones are long, 6-7 µm (38-43% head diameter at the level of the cephalic setae) and situated behind the outer labial ones. The amphids are spiral with 3 turns. They are 9-12 µm in diameter (47-63% corresponding body diameter). The stoma is long (20-21 µm) tubular with three large teeth in the anterior part and highly sclerotized walls on the posterior part. The pharyngeal muscles surround the cylindrical part of the stoma. The pharynx is cylindrical (243-314 µm long) with a swollen posterior bulb, 32-42 µm wide (corresponding body diameter is 50-59 µm). The nerve ring surrounds the pharynx at 42-50% and the opening of the ventral gland is at 52-57% of the pharyngeal length from the anterior. The cardia is small. The reproductive system is diorchic with opposed outstretched testes. The spermatozoa are packed tightly in the testes and they appear striated. The spicules are long and thin, slightly arcuate with a poorly developed captiulum (1.7 and 1.9 anal body diameter). There are 13 fine precloacal supplments that are situated 14 µm apart. The gubernaculum has a long caudal apophysis 12-17 µm and weakly refractive pieces. The tail is conical with a short cylindrical posterior part and a swollen tip with three terminal setae; (tail length divided by anal body diameter 2.6-3.1). The setae at the tail are more numerous than on the rest of the body. (ref. ID; 1902)

    Etymology

    This species name is given after Gerard Duineveld (Nioz, Texel). (ref. ID; 1902)

    Dorylaimopsis variabilis Muthumbi, Soetaert & Vincx, 1997 (ref. ID; 1902 original paper)

    Diagnosis

    Dorylaimopsis variabilis sp. n. is characterised by short labial sensilla; setiform cephalic sensilla (33-58% head diameter at the level of the cephalic setae); multispiral amphids with 2.75-3.0 turns; cuticular punctations with lateral differentiation of three longitudinal rows at the pharyngeal and tail regions and two longitudinal rows at the pharyngeal and tail regions and two longitudinal rows at the rest of the body; spicules that are long arcuate. D. variabilis sp. n. resembles D. mediterraneus Grimaldi de Zio, 1968 in the cuticular punctations, de mans ratios, and general body shape. They can be distinguished from each other by the number of amphideal turns (3.5 turns in D. mediterraneus); and although D. mediterraneus is the size of the larger form of D. variabilis sp. n., D. mediterraneus has much longer (187-225 µm) spicules that have a typical double curve and striations at the middle. (ref. ID; 1902)

    Descriptions

    Marine species. (ref. ID; 1902)
  • Female: They are similar to males in general body shape, cuticle, anterior sensilla and the tail. The reproductive system is amphidelphic with outstretched ovaries, the anterior branch to the left and the posterior one to the right of the intestine. Each branch has a long germinal zone and a growth zone that may or may not have a mature ovum and a uterus which may be partly filled with spermatozoa. (ref. ID; 1902)
  • Male: The body is cylindrical with a blunt anterior end and a conical cylindrical tail end. Head end is set off from the rest of the body by a constriction at the level of the cephalic sensilla. The cuticle is punctated on the median layer. Punctations begin at the level of the anterior border of the amphids. Laterally, the cuticle is raised and the punctations here are larger, more widely spaced and arranged in longitudinal rows. From the anterior end until 26-53 µm in front of the pharyngo-intestinal junction there are three longitudinal rows of dots, rest of the body until the level of the spicule has two longitudinal rows. The remaining posterior part has three rows of punctations similar to the pharyngeal region. On the dorsal and ventral sides, the punctations are smaller and arranged in transverse rows. Eight rows of somatic setae that appear to be inserted into grooves in the cuticle. Anterior sensilla are all distinct; inner and outer labial sensilla are tiny and the cephalic ones are long setiform, 33-50% head diameter at the level of the cephalic setae. The amphids are spiral with 2.75-3.0 turns 47-75% corresponding body diameter wide and situated immediately posterior of the cephalic setae. The stoma has an anterior conical part with three teeth and a posterior tubular part with highly sclerotised walls. The dorsal pharyngeal gland opening is at the base of the stoma. The pharynx is cylindrical, slightly expanded at the base. The nerve ring is located at 41-64% of the length of the pharynx from the anterior. The opening of the ventral gland cell is located at 48-75% of the length of the pharynx from the anterior and the ventral gland is at the pharyngo-intestinal junction. Cardia is small but distinct. The intestinal wall cells appear granular especially close to the cardia. The reproductive system is diorchic with opposed and outstretched testes. The anterior testis is to the left and the posterior one is right of the intestine. The anterior testis is longer and has larger spermatozoa which may be widely spaced, the posterior testis is shorter and has smaller spermatozoa. In some specimens, the spermatozoa may be widely spaced and vacuolated in the anterior testes but always closely packed in the posterior testis. It is possible that the two testes have spermatozoa at different developmental stages and hence the difference in their sizes. However, both small and large spermatozoa were observed in the female uterus; this may suggest that no change in size occurs either in the male of the female reproductive tract. It is therefore, possible that there are two types of spermatozoa, a larger type in the anterior testis and a smaller one in the posterior testis. The spicules are long (1.8-2.4 anal body diameter), arcuate and have a capitulum. The gubernaculum has a long caudal apophysis. There are 12-26 pre-cloacal supplements with very fine ducts. The tail is conico-cylindrical with a swollen tip (tail length divided by anal body diameter 2.9-3.9). There are numerous setae on the conical part of the tail and three (7-10 µm long) at the tip. The caudal glands open through three separate outlets at the terminal. (ref. ID; 1902)

    Etymology

    The species name is derived from the word variable. It is so called because it occurs in two different forms. (ref. ID; 1902)