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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Pleurotrocha

Pleurotrocha Ehrenberg, 1830

Class Monogonontaet: Order Ploimida: Family Notommatidae (ref. ID; 6806)

ref. ID; 1663

Eyespots present. Without definite auricles but often with a tuft of long cilia in the usual location of an auricle. Foot segmented. Toes separate or fused. Retrocerebral sac absent. Rami without teeth. Trophi symmetrical. Total length 110 to 250 µm. Littoral species. (ref. ID; 1663)

ref. ID; 1923

Manubrium with small ventral projection. (ref. ID; 1923)

ref. ID; 3245

Notommatid rotifers with short, stout, illoricate, ovoid or globose body, with and distinct neck separating the head and abdomen; the foot is long and cylindric or slightly tapering; the toes are very short and conical and may be either separate or fused. The corona is slightly oblique and consists of a marginal wreath of cilia with lateral, auricle-like tufts of long cilia adapted to swimming; the apical plate is unciliated and the buccal field evenly covered with short, close-set cilia; the mouth is near the ventral edge of the corona. The mastax is virgate and the trophi very simple; the fulcrum is long and rodlike, the rami triangular, curved and not denticulate; the manubria are very long and the basal plate much reduced; the unci are feeble and have only a single distinct tooth; the piston is very large. The eyespot is single and at the posterior end or on the lower surface of the ganglion; there is no trace of the retrocerebral organ. (ref. ID; 3245)
  1. Pleurotrocha altila Myers, 1940 (ref. ID; 2017)
  2. Pleurotrocha atlantica Myers, 1936 (ref. ID; 1345, 2017)
  3. Pleurotrocha aurea (Zawadowsky, 1916) Kutikova, 1970 (ref. ID; 2017)
    Species inquirendae. (ref. ID; 2017)
  4. Pleurotrocha bidentata Lie-Pettersen, 1905
    See; Encentrum bidentatum (ref. ID; 1345, 2019)
  5. Pleurotrocha chalicodis Myers, 1933 (ref. ID; 1345)
    See; Pleurata chalicodis (ref. ID; 2017)
  6. Pleurotrocha channa Myers, 1933 (ref. ID; 2017)
  7. Pleurotrocha constricta Ehrenberg, 1832 & 1838 (ref. ID; 3688) reported year? (ref. ID; 1345)
    See; Cephalodella constricta (ref. ID; 3688)
    Syn; Pleurotrocha constricta Hudson & Gosse, 1886 (ref. ID; 3688); Pleurotrocha leptura von Hofsten, 1909 (ref. ID; 3688)
  8. Pleurotrocha constricta Hudson & Gosse, 1886
    See; Cephalodella constricta (ref. ID; 3688)
  9. Pleurotrocha constricta Jennings, 1894
    See; Cephalodella parasitica (ref. ID; 1345, 3245)
  10. Pleurotrocha contorta Jennings, 1901
    See; Notommata contorta (ref. ID; 1345)
  11. Pleurotrocha daphnicola Thompson, 1892 (ref. ID; 3222), Harring 1913, Myers 1917, Wulfert 1939 or 1959
    See; Proales daphnicola (ref. ID; 1132, 1345, 2018, 3245, 3688)
  12. Pleurotrocha decipiens von Hofsten, 1909
    See; Proales decipiens (ref. ID; 1345, 3271)
  13. Pleurotrocha elengas Zawadowsky, 1926 (ref. ID; 2017)
    Species inquirendae. (ref. ID; 2017)
  14. Pleurotrocha gibba Hauer, 1921
    See; Encentrum grande (ref. ID; 1345, 3688)
  15. Pleurotrocha grandis Western, 1891
    See; Encentrum grande (ref. ID; 1345, 2019, 3334, 3688)
  16. Pleurotrocha hyaline Wulfert, 1939 (ref. ID; 1345, 2017, 3036, 3688)
  17. Pleurotrocha larvarum Wlastow, 1956; Kutikova (ref. ID; 2017)
    Species inquirendae. (ref. ID; 2017)
  18. Pleurotrocha latrunculus Harring, 1913
    See; Proales latrunculus (ref. ID; 1345)
  19. Pleurotrocha laurentina Harring, 1913
    See; Pleurotrocha petromyzon (ref. ID; 1345, 3245, 3688)
  20. Pleurotrocha leptura Ehrenberg, 1831 (ref. ID; 3688) reported year? (ref. ID; 1345)
    See; Cephalodella megalocephala (ref. ID; 3688)
  21. Pleurotrocha leptura von Hofsten, 1909
    See; Cephalodella constricta (ref. ID; 3688)
  22. Pleurotrocha littoralis Levander, 1894
    See; Encentrum pachidum (ref. ID; 1345)
  23. Pleurotrocha macropoda Zavadovsky, 1926
    See; Proales daphnicola (ref. ID; 3688)
  24. Pleurotrocha marina Bergendal, 1892
    See; Encentrum marinum (ref. ID; 1345, 1419, 3271, 3688)
  25. Pleurotrocha minima Montet, 1915
    See; Proales minima (ref. ID; 1345, 2018, 3245)
  26. Pleurotrocha mustela Milne, 1885
    See; Encentrum mustela (ref. ID; 1345, 2019, 3271, 3275, 3688)
  27. Pleurotrocha parasitica Jennings, 1900
    See; Cephalodella parasitica (ref. ID; 1345, 2017, 3245)
  28. Pleurotrocha petromyzon Ehrenberg, 1830 (ref. ID; 1345, 1923, 2017, 2266, 2268, 2757, 2824, 2841, 2932, 3245, 3271, 3688, 7846) or 1832 (ref. ID; 3275) reported year? (ref. ID; 2890) reported author and year? (ref. ID; 3292)
    Syn; Notommata gibba Ehrenberg, 1832 (ref. ID; 3688); Notommata petromyzon Ehrenberg, 1838 (ref. ID; 1345, 3245, 3271, 3688); Notops laurentinus Jennings, 1894 (ref. ID; 1345, 3688); Pleurotrocha laurentina Harring, 1913 (ref. ID; 1345, 3245, 3688); Pleurotrocha petromyzon Ehrenberg, 1830 (ref. ID; 1345); Proales laurentinus Jennings, 1896 (ref. ID; 1345, 3245, 3688); Proales petromyzon Hudson & Gosse, 1886 (ref. ID; 1345, 2757, 3245, 3271, 3688)
  29. Pleurotrocha reinhardti Manfredi, 1927
    See; Proales theodora (ref. ID; 1345)
  30. Pleurotrocha reinhardti von Hofsten, 1912
    See; Proales daphnicola (ref. ID; 1345), Proales reinhardti (ref. ID; 1345, 1419, 3245, 3688)
  31. Pleurotrocha robusta (Glasscott, 1893) (ref. ID; 2017, 3245) reported year? (ref. ID; 3403)
    Syn; Microcodides robustus Rousselet, 1895 (ref. ID; 3245); Microcodon robustus Glasscott, 1893 (ref. ID; 2017, 3245); Mikrocodides robustus Harring, 1913 (ref. ID; 2017, 3245)
  32. Pleurotrocha sigmoides Skorikov, 1896
    See; Proales daphnicola Thompson, 1892 (ref. ID; 3688)
  33. Pleurotrocha similis von Hofsten, 1912
    See; Proales similis (ref. ID; 2018, 3245, 3688)
  34. Pleurotrocha sordida Harring, 1913
    See; Proales sordida (ref. ID; 1345, 3688)
  35. Pleurotrocha thura Myers, 1993
    See; Pleurata thura (ref. ID; 2017)
  36. Pleurotrocha trypeta Harring & Myers (ref. ID; 1345, 3403)
  37. Pleurotrocha uncinata Zawadowski, 1926
    See; Dicranophorus uncinatus (ref. ID; 1345, 3688)
  38. Pleurotrocha vernalis Wulfert, 1935 (ref. ID; 1345)
    See; Pleurata vernalis (ref. ID; 2017)

Pleurotrocha hyaline Wulfert, 1939 (ref. ID; 1345, 2017, 3036, 3688)

Comments

This entirely colourless hyaline animal shows in the structure of its trophi a distinct difference from that given by Wulfert (1939) in the original description. The rami of my specimens are triangular, not extended in an alulae downwards. Median space between the rami is not elliptical, but cleft-like. There is no distal enlargement of the fulcrum - its is quite straight. The sharpness of the crutch-like formation on the manubrium is not turned upwards, as Wulfert has observed by his individuals, but is turned down-wards. The teeth on the unci are very delicate. Above the trophi is an epipharyngeal structure. (ref. ID; 3036)

Measurements

Total length 95-100; length of toes 10; length of trophi 12 µm. (ref. ID; 3036)

Pleurotrocha petromyzon Ehrenberg, 1830 (ref. ID; 1345, 1923, 2017, 2266, 2268, 2757, 2824, 2841, 2932, 3245, 3271, 3688, 7846) or 1832 (ref. ID; 3275) reported year? (ref. ID; 2890) reported author and year? (ref. ID; 3292)

Synonym

Notommata gibba Ehrenberg, 1832 (ref. ID; 3688); Notommata petromyzon Ehrenberg, 1838 (ref. ID; 1345, 3245, 3271, 3688); Notops laurentinus Jennings, 1894 (ref. ID; 1345, 3688); Pleurotrocha laurentina Harring, 1913 (ref. ID; 1345, 3245, 3688); Pleurotrocha petromyzon Ehrenberg, 1830 (ref. ID; 1345); Proales laurentinus Jennings, 1896 (ref. ID; 1345, 3245, 3688); Proales petromyzon Hudson & Gosse, 1886 (ref. ID; 1345, 2757, 3245, 3271, 3688)

Descriptions

The body is short, stout and gibbous; its greatest width is about one third of the entire length. The integument is soft and very flexible, but the general outline is nevertheless quite constant. The body is very transparent. The head and abdomen are separated by a rather shallow constriction. The head is small and short and somewhat oblique anteriorly. The abdomen is pyriform and tapers posteriorly to the base of the foot; there is no tail. The foot is long, cylindric and two-jointed; the length of the basal joint is equal to its width and the terminal joint is twice the length of the basal. The toes are very short, conical, acutely pointed and very slightly recurved at the tips; their length is about one twentieth of the length of the body. The antennae are minute setigerous papillae, the dorsal in the normal position, the lateral just beyond mid-length. The corona is frontal and consists of a circumapical band of cilia with two strongly developed lateral, auricle-like tufts of cilia adapted to swimming; the buccal field is evenly ciliated and the mouth is near the ventral edge of the corona. The mastax is virgate and the trophi of very simple form. The rami are approximately triangular, strongly curved longitudinally and have large, rounded alulae. The fulcrum is a very long, slender, tapering rod, incurved and slightly expanded at the posterior end. The unci are triangular plates with one weak ventral and a rudimentary second tooth; additional teeth are represented by three faint striae. The manubria are long and double-curved, tapering gradually from the broad base to the posterior end; near mid-length there is a small projecting lobe on the ventral edge; their longitudinal direction is nearly at right angles to the fulcrum. Two small curved rods are imbedded in the anterior walls of the mastax and serve to support the edges of the mouth during the pumping action. The oesophagus is short and slender. The gastric glands are elongate oval and strongly compressed laterally. There is no constriction separating the stomach and intestine. The ovary is large and of a somewhat irregularly oval outline. A small bladder is present. The foot glands are very long and nearly cylindric; they discharge into a large mucus reservoir at the base of the toes. The ganglion is large and saccate, reaching nearly to the posterior end of the mastax. No retrocerebral organ is present. The eyespot is at the extreme end of the ganglion and consists of a very small sphere of minute pigment granules. (ref. ID; 3245)

Measurements

Total length 225-250; toes 12; trophi 32 µm. (ref. ID; 3245)

Total length 215-220; length of toes 16-22 µm. (ref. ID; 3275)

Pleurotrocha robusta (Glasscott, 1893) (ref. ID; 2017, 3245) reported year? (ref. ID; 3403)

Synonym

Microcodides robustus Rousselet, 1895 (ref. ID; 3245); Microcodon robustus Glasscott, 1893 (ref. ID; 2017, 3245); Mikrocodides robustus Harring, 1913 (ref. ID; 2017, 3245)

Descriptions

The body is short, stout and gibbous; its greatest width is about two fifths of the entire length. The integument is leathery and the outline remains quite constant. The entire body is very transparent. The head and abdomen are separated by a deep constriction. The head segment is short and very broad; its width is about two thirds of the greatest width of the body. The abdomen is globose and ends in a short, sleeve-like tail surrounding the base of the foot. On the posterior half of the abdomen are five or six well marked longitudinal folds; they are continuous from side to side and not interrupted posteriorly. The foot is long, stout and slightly tapering; it has three joints of approximately equal length. The toe is single and abruptly reduced near the middle; its length is a little less than one tenth of the total length of the animal. As there are two well developed foot glands it is evident that the single toe is a result of the fusion of two originally separate toes. The dorsal antenna is a large, knoblike elevation on the posterior part of the head, immediately in front of the neck; it has a funnel-shaped central depression with a small tuft of sensory setae. The lateral antennae are minute tubules with a few very short setae in the normal position. The corona is oblique and consists of a circumapical band of cilia with two lateral, auricle-like tufts of strong cilia adapted to swimming; the buccal field is evenly ciliated. The mouth is in the normal position, near the ventral margin of the corona, and not in the center, as stated by Rousselet. The mastax is virgate and of very simple form. The fulcrum is very long, slender and tapering; the posterior end is slightly expanded for the attachment of them muscles of the piston. The rami are roughly triangular and without teeth or denticulations; a somewhat abrupt bend divides them into a rather short ventral and a long dorsal section. The alulae are very prominent. The unci have only one tooth, slender and clubbed at the tip; there is no basal plate. The manubria are very long their general direction is nearly at right angles to the fulcrum, so that they almost reach the dorsal side; the basal plate is small and its edges are parallel to the strongly curved anterior end of the principal rib; the posterior branch is very slender and slightly recurved. The piston is bulky, but not very powerful. The epipharynx consists of two slender, strongly curved rods, imbedded in the walls of the mastax at the sides of the mouth. The oesophagus is short and slender. There is no constriction between stomach and intestine. The gastric glands are small and nearly spherical. The ovary is irregularly elongate and reaches from the bladder nearly to the mastax; the nuclei are large and irregularly polygonal. A fairly large bladder is present. The two foot glands are tapering and fully as long as the foot. The ganglion is large and saccate. There is no traced the retrocerebral organ. Thee eyespot is well towards the front of the head and seems to be seated on the mastax instead of the lower surface of the ganglion, as it follows the movements of the mastax. (ref. ID; 3245)

Comments

As this species has nothing in common with Mikrocodides chlaena except the fused toes, it has been transferred to Pleurotrocha, with which it seems to agree fairly well. No good reasons ever existed of referring it to Mikrocodides; the fused toes can not be considered a generic character to the exclusion of everything else. The supposed identity of the corona in the two species is an error; neither M. chlaena nor P. robusta has the mouth at the center of the corona; as pointed out by De Beauchamp, M. chlaena has a corona of the type of Cyrtonia, and the mastax is malleate. (ref. ID; 3245)

Measurements

Total length 180-200; foot and toes 55-60; toes 16-18; trophi 22 µm. (ref. ID; 3245)