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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Asplanchna

Asplanchna Gosse, 1850 (ref. ID; 7815)

Order Ploimida: Family Asplanchnidae (ref. ID; 7097)

ref. ID; 766

The genus Asplanchna is subdivided into two subgenera. One contains species with spherical yolk glands (Asplanchna herricki, A. priodonta), the other contains species with horse-shaped yolk glands (A. girodi, A. brightwelli, A. intermedia, A. sieboldi, A. silvestrii). Sudzuki (1964) has suggested elevating these two groups of species to genus status calling then Asplanchna and Asplanchnella, respectively. This proposal, however, has not been generally accepted. (ref. ID; 766)

ref. ID; 1663

Large transparent species, usually 400 to 2000 µm long. Sac-shaped, with a well-developed corona. Intestine and anus lacking. Mastax incudate. Vitellarium horseshoe-shaped or globose. Often viviparous. Morphology variable. Body of one species with humps or wing-like processes. Male present. Several very common plankton species. Predatory. (ref. ID; 1663)

ref. ID; 1931

Illoricate rotifers with delicate sacciform body, incudate trophi and corona as circumapical ring of cilia. Intestine, foot and toes are wanting. Viviparous. Difficult and variable genus. Sudzuki (1964) split the genus into Asplanchna and Asplanchnella including species with 8-12 nuclei and more than 20 nuclei in the germovitellarium respectively. Edmondson (1959) stated that the ovary in A. priodonta Gosse, A. herricki de Guerne is spherical and band or horse-shoe shaped in the rest. (ref. ID; 1931)

ref. ID; 3114

The specimens of the genus Asplanchna have without any exception a transparent, soft sock-formed body, which is changeable in shape as both internal and external organs move. This fact makes their identification highly difficult. And, only one available character is considered to be the features of the trophi. On the other hand, Wesenberg-Lund (1923, p.255) mentions as follows: 'The species has been founded upon the structure of the jaws, number of eyes, form of ovarium, form of the body, form of the gastric glands, number of vibratile tags and shell structure of the resting egg. (ref. ID; 3114)

ref. ID; 4595

Without foot. (ref. ID; 4595)
  1. Asplanchna amphora Hudson, 1889 (ref. ID; 2284) or (Hudson) Western, 1898 (ref. ID; 1345)
    See; Asplanchna brightwelli
    Syn; Asplanchna brightwelli Harring, 1913 (ref. ID; 1345, 2284)
  2. Asplanchna anglica Wierzejski, 1882
    See; Asplanchna priodonta (ref. ID; 3688)
  3. Asplanchna asymmetrica (Shiel & Koste, 1985) (ref. ID; 1986)
  4. Asplanchna bowesii or bowessii Gosse, 1850
    See; Asplanchna brightwelli (ref. ID; 3271, 3688)
  5. Asplanchna brightwelli (Gosse, 1850) (ref. ID; 766, 773, 1345, 1804, 1808, 1931, 2385, 2619, 2715, 3083, 3271, 3275, 3514, 3688) reported year? (ref. ID; 2944, 3258, 3262, 3426, 3600, 5022) reported author and year? (ref. ID; 1519, 2750, 2979, 3242, 3292, 5088), brightwellii Gosse, 1850 (ref. ID; 3059)
    See; Asplanchna girodi
    Syn; Apus anglica Schoch, 1864 (ref. ID; 3688) or 1868 (ref. ID; 1345, 3271); Ascomorpha anglica Perty, 1852 (ref. ID; 1345, 3271, 3688); Asplanchna amorpha Hudson, 1889 (ref. ID; 3271); Asplanchna bowesii Gosse, 1850 (ref. ID; 3271) or bowessii Gosse, 1850 (ref. ID; 3688); Asplanchna brightwelli ceylonica Daday, 1898 (ref. ID; 3271, 3688); Asplanchna ceylonica Daday, 1898 (ref. ID; 3271, 3688); Asplanchna girodi De Guerne, 1888 (ref. ID; 3271); Asplanchna imhofi de Guerne, 1888 (ref. ID; 3688); Notommata anglica Leydig, 1854 (ref. ID; 1345, 3271, 3688)
  6. Asplanchna brightwelli ceylonica Daday, 1898
    See; Asplanchna brightwelli (ref. ID; 3271, 3688)
  7. Asplanchna brightwelli girodi Voronkow, 1907
    See; Asplanchna girodi (ref. ID; 3688)
  8. Asplanchna ceylonica Daday, 1898
    See; Asplanchna brightwelli (ref. ID; 3271, 3688)
  9. Asplanchna ebbesborni or ebbesbornii Hudson, 1883
    See; Asplanchna sieboldi (ref. ID; 2757, 3688)
  10. Asplanchna eupoda Gosse, 1887
    See; Harringia eupoda (ref. ID; 1345, 3688)
  11. Asplanchna girodi de Guerne, 1888 (ref. ID; 766, 773, 1345, 2723, 2912, 3688) reported year? (ref. ID; 2889, 2890, 2899, 3402, 3426) reported author and year? (ref. ID; 1519, 3242)
    See; Asplanchna brightwelli
    Syn; Asplanchna brightwelli Harring, 1913 (ref. ID; 1345); Asplanchna brightwelli girodi Voronkow, 1907 (ref. ID; 3688)
  12. Asplanchna helvetica Imhof, 1884; Lauterborn 1916; Kuttner 1924; Auerbach, Maerker, Schmalz, 1924/26; Scheffelt, 1926/27
    See; Asplanchna priodonta (ref. ID; 2841, 3688)
  13. Aspalnchna henrietta Langhans (ref. ID; 2970)
  14. Asplanchna herricki de Guerne, 1888 (ref. ID; 1345, 1923, 3688) reported year? (ref. ID; 2814, 5022) reported author and year? (ref. ID; 1519), herrickii de Guerne, 1888 (ref. ID; 3059) reported year? (ref. ID; 3263) reported author and year? (ref. ID; 5389)
  15. Asplanchna hungarica Daday, 1891
    See; Asplanchna sieboldi (ref. ID; 1345, 3688)
  16. Asplanchna imhofi de Guerne, 1888
    See; Asplanchna brightwelli (ref. ID; 3688)
  17. Asplanchna intermedia Hudson, 1886 (ref. ID; 766, 773, 1345, 1931, 2825, 3050) reported author and year? (ref. ID; 3242)
  18. Asplanchna krameri de Guerne, 1888
    See; Asplanchna priodonta (ref. ID; 3688)
  19. Asplanchna magnificus Herrick, 1885
    See; Asplanchnopus multiceps (ref. ID; 1345, 3688)
  20. Asplanchna myrmeleo Eyferth, 1878
    See; Asplanchnopus multiceps (ref. ID; 1345, 3688)
  21. Asplanchna myrmelio Eyferth, 1878
    See; Asplanchnopus multiceps (ref. ID; 2757)
  22. Asplanchna papuana Daday, 1897
    See; Asplanchnopus multiceps (ref. ID; 3688)
  23. Asplanchna priodonta Gosse, 1850 (ref. ID; 1345, 1402, 1804, 1923, 2268, 2278, 2617, 2619, 2715, 2814, 2841, 2887, 3059, 3083, 3158, 3275, 3688, 4595) reported year? (ref. ID; 2889, 3046, 3066, 3086, 5022, 5029) reported author and year? (ref. ID; 1519, 5389, 6844), priodonta priodonta Gosse, 1850 (ref. ID; 3114, 3514)
    Syn; Asplanchna anglica Wierzejski, 1882 (ref. ID; 3688); Asplanchna helvetica Imhof, 1884 (ref. ID; 2841, 3688), Lauterborn 1916 (ref. ID; 2841), Kuttner 1924 (ref. ID; 2841), Auerbach, Maerker, Schmalz, 1924/26 (ref. ID; 2841) or Scheffelt, 1926/27 (ref. ID; 2841); Asplanchna krameri de Guerne, 1888 (ref. ID; 3688); Asplanchna priodonta helvetica Langhans, 1905 (ref. ID; 3688); Asplanchna priodonta minor Voronkow, 1907 (ref. ID; 3688); Asplanchna priodonta pelagica Zacharias, 1892 (ref. ID; 3688); Notommata anglica Wierzejski, 1881 (ref. ID; 3688)

    Quote from ref. ID; 3114

  24. Asplanchna priodonta helvetica Imhof (ref. ID; 7097)
  25. Asplanchna priodonta helvetica Langhans
    See; Asplanchna priodonta (ref. ID; 3688)
  26. Asplanchna priodonta herricki (ref. ID; 2261)

    Quote from ref. ID; 2261

  27. Asplanchna priodonta minor Voronkow, 1907
    See; Asplanchna priodonta (ref. ID; 3688)
  28. Asplanchna priodonta pelagica Zacharias, 1892
    See; Asplanchna priodonta (ref. ID; 3688)
  29. Asplanchna priodonta sirakabana Sudzuki, 1958 (ref. ID; 3114)

    Quote from ref. ID; 3114

  30. Asplanchna priodonta var. henrietta Langhans, 1906 (ref. ID; 3688)
  31. Asplanchna sieboldi (Leydig, 1854) (ref. ID; 766, 773, 1345, 1834, 2385, 2715, 2757, 3688) reported year? (ref. ID; 2890, 3089) reported author and year? (ref. ID; 1519, 2750, 2943, 2989, 3292, 3373, 6844), sieboldii (Leydig, 1854) (ref. ID; 3059) reported year? (ref. ID; 3523)
    Syn; Apus amphora Hudson, 1889 (ref. ID; 1345); Apus ebbesborni Hudson, 1883 (ref. ID; 1345); Apus sieboldi Eyferth, 1878 (ref. ID; 1345, 3688) or Schoch, 1868 (ref. ID; 1345, 3688); Asplanchna ebbesborni Hudson, 1883 (ref. ID; 3688), ebbesbornii Hudson, 1883 (ref. ID; 2757); Asplanchna hungarica Daday, 1891 (ref. ID; 1345, 3688); Notommata sieboldi Leydig, 1854 (ref. ID; 1345, 3688); Notommata sieboldii Leydig, 1854 (ref. ID; 3059)
  32. Asplanchna sieboldi f. cruciformis (ref. ID; 1808)
  33. Asplanchna sieboldi urawaensis Sudzuki, 1956 (ref. ID; 1345, 3067, 3114)
  34. Asplanchna silvestri Daday, 1902 (ref. ID; 1923), silvestrii (ref. ID; 2285, 3218)
  35. Asplanchna silvestris Daday, 1902 (ref. ID; 766, 1345)
  36. Asplanchna tropica Koste & Tobias (ref. ID; 1831, 2797)

Asplanchna amphora Hudson, 1889 (ref. ID; 2284) or (Hudson) Western, 1898 (ref. ID; 1345)

Synonym

Asplanchna brightwelli Harring, 1913 (ref. ID; 1345, 2284)

Comments

Although Harring (1913) gives this species as a synonym for A. brightwelli, and there are, as Voigt (1957) shows, differences the trophi of the two species. For this reason A. amphora is considered to be a valid species. (ref. ID; 2284)

Measurements

Total length 400; width over humps 300; length of trophi 75 µm. (ref. ID; 2284)

Asplanchna brightwelli (Gosse, 1850) (ref. ID; 766, 773, 1345, 1804, 1808, 1931, 2385, 2619, 2715, 3083, 3271, 3275, 3514, 3688) reported year? (ref. ID; 2944, 3258, 3262, 3426, 3600, 5022) reported author and year? (ref. ID; 1519, 2750, 2979, 3242, 3292, 5088), brightwellii Gosse, 1850 (ref. ID; 3059)

See

Asplanchna girodi

Synonym

Apus anglica 1864 (ref. ID; 3688) or Schoch, 1868 (ref. ID; 1345, 3271); Ascomorpha anglica Perty, 1852 (ref. ID; 1345, 3271, 3688); Asplanchna amorpha Hudson, 1889 (ref. ID; 3271); Asplanchna bowesii Gosse, 1850 (ref. ID; 3271) or bowessii Gosse, 1850 (ref. ID; 3688); Asplanchna brightwelli ceylonica Daday, 1898 (ref. ID; 3271, 3688); Asplanchna ceylonica Daday, 1898 (ref. ID; 3271, 3688); Asplanchna girodi De Guerne, 1888 (ref. ID; 3271); Asplanchna imhofi de Guerne, 1888 (ref. ID; 3688); Notommata anglica Leydig, 1854 (ref. ID; 1345, 3271, 3688)

Diagnosis

Forms to be named A. brightwelli were firsts described by Brightwell (1848). He figured the trophi and resting egg, as well as the female and male. The ramus had a tooth protruding from the inner margin of the scapus, and the resting egg was similar to the one described of these species by Gilbert & Wurdak (1978). The rotifer described by Brightwell and then Dalrymple was named A. brightwelli by Gosse (1850). (ref. ID; 766)

Descriptions

This species has trophi with an apophysis on the bulla, lobed yolk gland nucleoli, polymorphic females, and males with lateral body-wall outgrowths. (ref. ID; 766)

Body transparent, thin and sacciform. Rami with horne-like projections at outer margins of the base and inner spines at the middle. Vitellarium diagnostic, horse-shoe shaped and with 30-32 nuclei. (ref. ID; 1804)

Body transparent, thin and sacciform. Trophi incudate with rami possessing hornlike projections at outer margins of the base and inner spines at the middle. Flame bulbs 18. Germovitellarium with 32 nuclei. Feeds on other rotifers. (ref. ID; 1931)

Vitellarium horse-shoe shaped with more than 30 nuclei. (ref. ID; 2715)

Polymorphism and sexuality to the effects of prey-type and clonal variation. (ref. ID; 2750)

Vitellarium with ca. 30 nuclei. (ref. ID; 3083)

  • Resting egg: The outer envelope is composed of considerably larger, spherical elevations, and the relatively dark envelope underneath has a striated appearance. (ref. ID; 773)

    Mating behavior

  • Swimming Activity. The females of A. brightwelli swim in a smooth, glinding pattern along a straight course until another animal or the wall of the culture dish is encountered. At this time they simply glance or graze off the surface of the encountered object, sometimes turning 180 degrees in the process, and resume swimming along another straight course. This almost-rhythmic forward motion of the female is strikingly contrasted to that of the male rotifer, which is frequently interrupted by a spasmodic, jerking activity often accompanied by a change in directon. The males usually swim with a slight propensity toward a circular pattern, with their ventral surface facing the center of the arc. (ref. ID; 5088)
  • Courtship. The complete mating process of A. brightwelli requires about 45-60 sec and can be divided into four successive stages: (1) coronal contact, (2) body arching, (3) copulatory organ attachment, and (4) copulation. The mating process appears to be initiated following a random encounter of a male and female. The first step after encounter involves placement of the male corona in close apposition to the cuticular surface of the female. The female continues her smooth swimming motion, only occasionally contracting the body wall musculature causing a brief interruption in her forward progress. The male follows along, with his coronal region remaining closely associated with the female's integument. From 16 mm cinematographic observations this association sometimes appears to be more than a simple anatomical juxtaposition. On some occasion it appears to be a firm attachment which causes the cuticle of the female to become visibly taut in the region associated with the corona of the male as the female twists and turns during swimming. This initial phase of attachment usually lasts 3-5 sec. After forming the association of the male corona and female integument, the male being to hunch or arch his body and move the copulatory organ closer to the body of the female. The male may remain in this position for a few seconds or he may continue the arching process, bringing the copulatory organ in close contact with the cuticular surface of the female. During this hunching phase the male begins to move across the surface of the female, usually around the short axis of her body. This migration occurs in such a manner at the corona of the male remains contiguous with the female integument at all times. During these first two stages, requiring 10-15, sometimes 20 sec, both male and female may discontinue the courtship activity. The female may rotate around the long axis of her body or completely contract her body musculature causing the male to lose contact. The male may halt the courtship behavior simply by straightening his body and swimming away. If courtship is continued, the third stage of the process ensues; the copulatory organ of the male is attached to the female integument. This attachment has been observed to occur at almost every possible locus around the surface of the female body; near the coronal area or at the posterior end of the female at the level of the gastric glands, stomach, and vitellarium. During this 10-20 sec attachment phase the male remains in a hunched position with both the corona area and the tip of the copulatory organ in contact with the female integument. After attachment, the corona of the male is withdrown from the body of the female and the male assumes his normal straight or erect position. This phase of actual copulation usually lasts 20-45 sec, although one unusually prolonged contact of 65 sec was recorded on 16 mm film. The final attachment of the copulatory organ to the female integumental surface apparently is a strong bond, since the female, being ca. 1+1/2 - 3 times the size of the male, can continue to swim and drag the male along solely by the copulatory organ. However, this bond between the copulatory organ the female is of such a nature that it also allows the female to rotate 360 degrees around the point of attachment without rupturing the union. After completing the copulatory process, the male simply swims away in his usually saltatory fashion. The female, however, begins a series of body wall contractions, interrupting her forward motion for approximately 10-20 sec prior to resuming her normal smooth swimming behavior. (ref. ID; 5088)
  • Anomalous Mating. The males of A. brightwelli have been observed to mate with other males, newborn females, and with other females two and three times their own size taken from stock mictic cultures containing vitamin E. They have also mated with young females of similar size taken from amictic cultures without vitamin E. Normally, these mating have occurred between two individuals. However, occasionally, relationships such as two or three males simultaneously attached to one female, or one male copulating with one female while another male copulates with him have been observed. (ref. ID; 5088)
  • Electron microscopy of mating. Light microscopic observations indicate that the tip of the copulatory organ is tightly pressed against the female integument during copulation. These observatios appear confirmed by examination of copulation rotifers with the electron microscope. Fig.3 illustrates a section through the periphery of the copulatory organ and the female integument. A closer examination of the juxtaposed cuticles indicates that an additional substance is present. It can be seen as a thin, wispy fibrous layer running perpendicular to the outer cuticular fibers, described by Koehler (1965), and parallel to the surface of the cuticle. Fig.6, illustrating the peripheral region of the juxtaposed cuticles in Fig.3, shows that when the tightly pressed cuticular surfaces separate at their outer boundaries, this extra fibrous the material adheres closely to the surface of the female integument. In this region the fibrous substance is arranged in two distinct layers parallel to the female integment. A similar extra fibrous substances can also be seen when examining the urethra of a male rotifer fixed while copulating. The fibrous material is found between the walls of the urethra arranged perpendicular to the cuticular fibers. An extra fibrous substance such at this is never present in the urethra of non-copulating male rotifers. In the region between the extreme tip of the urethral canal and the juxtaposed female cuticle of copulating rotifers, an amorphous, fuliginous material can be observed. This substance is found in the central planes through the longitudinal axis of the copulatory organ and completely fills the triangular-shaped cavity formed by the tip of the male urethra and the female cuticle. Throughout the entire investigation, the rigid rods synthesized by the non-functional spermatozoa were never observed more anterior than the sperm duct region of the testis. They were not observed at any point along the male urethra nor within the female pseudocoel of copulation females. (ref. ID; 5088)

    Examined materials

    The stock culture C//5B45(7)6 of the rotifer Asplanchna brightwelli was provided by C.W. Birky. (ref. ID; 5088)

    Measurements

    Resting egg diameter 145.6+/-1.6 (range 127.4-163.8) µm. (ref. ID; 773)

    Total length 490; maximum width 280 µm. (ref. ID; 1804)

    Length of the body 350; width 196; trophi 70 µm. (ref. ID; 1931)

    Length 600 µm. (ref. ID; 2385)

    Length of body 1250, most of the specimens examined measured close to 1 mm, in length even in the contracted state; trophi 100 µm. (ref. ID; 2715)

    Body length 330-465 (contracted); vitellarium 224 in length. (ref. ID; 3083)

    Asplanchna girodi de Guerne, 1888 (ref. ID; 766, 773, 1345, 2723, 2912, 3688) reported year? (ref. ID; 2889, 2890, 2899, 3402, 3426) reported author and year? (ref. ID; 1519, 3242)

    See

    Asplanchna brightwelli

    Synonym

    Asplanchna brightwelli Harring, 1913 (ref. ID; 1345); Asplanchna brightwelli girodi Voronkow, 1907 (ref. ID; 3688)

    Descriptions

    A. girodi was mistakenly called A. brightwelli by many authors, including Rousselet (1901), until the inconsistency was noted and clarified by Waniczek (1930). The yolk glands nucleoli are rounded and not lobed. The jaws or trophi are unique in that there is no process or apophysis protruding from the bulla (proximal portion) of the ramus. The female is monomorphic, and the male has no lateral humps or body-wall outgrowths. (ref. ID; 766)

    Resting egg: The surface consists of closely apposed, spherical elevations. (ref. ID; 773)

    Comments

    The identification of A. girodi poses few problems, the particular shape of the ovarium, and of the mastax which has either no inner tooth on the rami or a very weakly developed tooth (Beauchamp 1951) formed by the middle part of the uncus are reliable and stable characters. Strong apophysis at the base of the rami, as in Asplanchna brightwelli, are absent; small, pointed apophysis are present. The subterminal lamelli are strongly developed and idented at their tips. (ref. ID; 2912)

    Measurements

    Resting egg diameter 163.8+/-1.3 (range 145.6-182.0) µm. (ref. ID; 773)

    Asplanchna herricki de Guerne, 1888 (ref. ID; 1345, 1923, 3688) reported year? (ref. ID; 2814, 5022) reported author and year? (ref. ID; 1519), herrickii de Guerne, 1888 (ref. ID; 3059) reported year? (ref. ID; 3263) reported author and year? (ref. ID; 5389)

    Descriptions

    This species is distinguished by the presence of a 2-celled glandular structure near the cloaca. (ref. ID; 1923)

    Asplanchna intermedia Hudson, 1886 (ref. ID; 766, 773, 1345, 1931, 2825, 3050) reported author and year? (ref. ID; 3242)

    Diagnosis

    The female and especially the male of a form to be called A. intermedia were first descried by Hudson (1875) as a new and yet unnamed species. The form was called intermedia by Hudson in the supplement of Hudson & Gosse (1889), but it was not clearly differentiated from A. brightwelli and A. sieboldi. Rousselet (1901) was the first to describe in detail both the female and the male of a form he identified as A. intermedia, and he made accurate comparisons between this form and both A. sieboldi and A. girodi (improperly called A. brightwelli). The trophi of A. intermedia do not have a tooth protruding from the inner margin of scapus and this differ markedly from those of A. brightwelli and A. sieboldi. Beauchamp (1951) reviewed the status of A. intermedia, A. brightwelli, and A. sieboldi and decided to include A. intermedia and A. sieboldi under the name A. brightwelli sensu latissimo. Gilbert (1968) tentatively chose to include all of these forms under the name A. brightwelli Gosse. Wurdak et al (1979) were proposing to call both A. intermedia Hudson and A. sieboldi Leydig distinct species separate from A. brightwelli Gosse. (ref. ID; 766)

    Descriptions

    This species has trophi with an apophysis on the bulla, lobed yolk gland nucleoli, polymorphic females, and males with lateral body-wall outgrowths. (ref. ID; 766)

    Rami with hornlike projections at the outer margins of the base and without spines in the middle. Flame bulbs 20 and germovitellarium with 36 nuclei. (ref. ID; 1931)

  • Resting egg: The surface is corrugated, and the regularly spaced dots from the envelope underneath are visible. (ref. ID; 773)

    Measurements

    Resting egg diameter 160.5+/-1.1 (range 145.6-182.0) µm. (ref. ID; 773)

    Length of the body 490; width 280; trophi 84 µm. (ref. ID; 1931)

    Maximum length of the body 427; maximum breadth of the body 264 µm. (ref. ID; 3050)

    Asplanchna priodonta Gosse, 1850 (ref. ID; 1345, 1402, 1804, 1923, 2268, 2278, 2617, 2619, 2715, 2814, 2841, 2887, 3059, 3083, 3158, 3275, 3688, 4595) reported year? (ref. ID; 2889, 3046, 3066, 3086, 5022, 5029) reported author and year? (ref. ID; 1519, 5389, 6844), priodonta priodonta Gosse, 1850 (ref. ID; 3114, 3514)

    Synonym

    Asplanchna anglica Wierzejski, 1882 (ref. ID; 3688); Asplanchna helvetica Imhof, 1884 (ref. ID; 2841, 3688), Lauterborn 1916 (ref. ID; 2841), Kuttner 1924 (ref. ID; 2841), Auerbach, Maerker, Schmalz, 1924/26 (ref. ID; 2841) or Scheffelt, 1926/27 (ref. ID; 2841); Asplanchna krameri de Guerne, 1888 (ref. ID; 3688); Asplanchna priodonta helvetica Langhans, 1905 (ref. ID; 3688); Asplanchna priodonta minor Voronkow, 1907 (ref. ID; 3688); Asplanchna priodonta pelagica Zacharias, 1892 (ref. ID; 3688); Notommata anglica Wierzejski, 1881 (ref. ID; 3688)

    Descriptions

    Vitellarium rounded. Trophi characteristic; inner edge of each ramus with 4-6 teeth at its anterior end, also the base of ramus with two lateral prolongations. (ref. ID; 1804)

    This species is very common in lake plankton. (ref. ID; 1923)

    Vitellarium rounded. The trophi are characteristic and the inner edge of the rami has 4 to 6 teeth at the anterior end. There are also two lateral prolongations at the base of the rami. Fulcrum narrow. (ref. ID; 2715)

    Vitellarium with 8 nuclei. Trophi belongs to priodonta in type. Ramus with 5 teeth. (ref. ID; 3083)

    The morphology of the trophi is the chief diagnostic factor. Nevertheless, this shows extreme variation in the position and number of teeth present on the rami. In some the teeth were blunt, while in others they were pointed. Some had wide allulae from the sides of the trophi, and in others small thin projections were discernible, the degree of curvature of the anteriormost teeth also differed in specimens from some localities. (ref. ID; 3086)

    Body very transparent. Ovary roundish. Without cement glands. Viviparous. Freshwater species, found in estuaries. (ref. ID; 4595)

    SEM micrograph illustrating trophi. (ref. ID; 6844)

  • Egg: (ref. ID; 3066, 3114)

    Quote from ref. ID; 3066

    Quote from ref. ID; 3114

  • Male: Male present. (ref. ID; 3066)

    Quote from ref. ID; 3066

    Measurements

    Size variation during the year is not significantly different from average length:breadth=408:295 µm. The longest animals, up to 700 µm appear in late summer. (ref. ID; 1402)

    Total length 520; maximum width 300 µm. (ref. ID; 1804)

    Length 500; max. width 200 µm. (ref. ID; 2278)

    Length of body 1,200; length of trophi 60 µm. (ref. ID; 2715)

    Body length 328-490 (contracted); body width 196-270; stomach 100-110x80-90; gastric glands 50-52x48-50; vitellarium 60x42; vitellarium nuclei 8-10; ramus 48 µm. (ref. ID; 3083)

    Body length 350-550; body width 295-400 µm. (ref. ID; 3275)

    Length 400-1,500 µm. (ref. ID; 4595)

    Asplanchna sieboldi (Leydig, 1854) (ref. ID; 766, 773, 1345, 1834, 2385, 2715, 2757, 3688) reported year? (ref. ID; 2890, 3089) reported author and year? (ref. ID; 1519, 2750, 2943, 2989, 3292, 3373, 6844), sieboldii (Leydig, 1854) (ref. ID; 3059) reported year? (ref. ID; 3523)

    Synonym

    Apus amphora Hudson, 1889 (ref. ID; 1345); Apus ebbesborni Hudson, 1883 (ref. ID; 1345); Apus sieboldi Eyferth, 1878 (ref. ID; 1345, 3688) or Schoch, 1868 (ref. ID; 1345, 3688); Asplanchna ebbesborni Hudson, 1883 (ref. ID; 3688), ebbesbornii Hudson, 1883 (ref. ID; 2757); Asplanchna hungarica Daday, 1891 (ref. ID; 1345, 3688); Notommata sieboldi Leydig, 1854 (ref. ID; 1345, 3688), Notommata sieboldii Leydig, 1854 (ref. ID; 3059)

    Diagnosis

    The sieboldi form was first described by Leydig (1854). Definitely synonymous ebbesborni and amphora forms were subsequently described by Hudson in Hudson & Gosse (1886, 1889). As indicated above, A. sieboldi was considered by Beauchamp (1951) to be one of two forms, along with A. intermedia, comprising A. brighwelli sensu latissimo and by Gilbert (1968) to be possibly synonymous with A. brighwelli Gosse. (ref. ID; 766)

    Descriptions

    This species has trophi with an apophysis on the bulla of the ramus, lobed yolk gland nucleoli, polymorphic females, and males with lateral body-wall outgrowths. (ref. ID; 766)

    A departure from the type is an auxiliary tooth on the outside of each ramus. (ref. ID; 2385)

    Vitellarium horse-shoe shaped like in A. brightwelli but can be easily identified by the structure of the trophi. The trophi of the Sri Lanka specimens correspond exactly to the drawings of Hauer (1938) for material from Indonesia. The only minor difference from Hauer's drawings is in the shape do the alullae arising from the rami and in the single spine-like projection inwards in the middle of the rami. (ref. ID; 2715)

    Polymorphism and sexuality to the effects of prey-type and clonal variation. (ref. ID; 2750)

    SEM micrograph illustrating trophi. (ref. ID; 6844)

  • Resting egg: The surface is covered with plate-like structures. (ref. ID; 773)

  • Male: Male present. (ref. ID; 2385)

    Polymorphism

    Asplanchna sieboldi exhibits pronounced sexual and developmental polymorphism. The males are much smaller than females and are structurally reduced, lacking both a feeding apparatus and a functional digestive system. They have two, usually very large, lateral humps or body wall outgrowths. Laboratory studies have shown that male production is induced by dietary alpha-tocopherol (Gilbert & Thompson 1968). In the absence of this compound females always produce diploid eggs which develop parthenogenetically into females. When such female-producing or amictic females are given a diet rich in alpha-tocopherol, they give birth to some male-producing or mictic female offspring. These produce haploid eggs which develop parthenogenetically into males or, if fertilized, into thick-walled resting eggs. In addition to the sexual dimorphism and the female reproductive polymorphism, there is a marked, non-genetic variation in the size and shape of females. These may be of three basic morphotypes with intermediate. A relatively small, saccate type hatches from resting eggs. Saccates may produce offspring of their own or of the cruciform morphotype. Cruciforms are larger than saccate and have four, variably sized humps or outgrowths of the body wall -two lateral, one posterodorsal, and one posterior. Cruciforms may produce saccate, cruciform, or campanulate offspring. Campanulates are considerably larger than cruciforms and have a disproportionately wider corona and body than saccates (Gilbert 1973). The campanulates in my clones, however, are smaller and less broad at the corona than those described by Powers (1912). Campanulates may produce campanulate or cruciform offspring, or they may produce increasingly small offspring which after several generation are saccate. (Gillbert 1973). (ref. ID; 766)

    The first report of female polymorphism was that of von Daday (1888). He found that small saccate, or sac-shaped, animals could produce offspring which were much larger and which had pronounced humps, an observation repeated by Lange (1911), Powers (1912), and Wesenberg-Lund (1930). Powers also discovered that the cruciform, or humped, morphotype could give birth to yet another, even larger, campanulate, or bell-shaped, morphotype. The bodies of adult saccate, cruciform, and campanulate females are respectively 500 to 800, 1,000 to 1,400, and 1,200 to 1,800 µm long. Saccates are cylindrical, whereas cruciforms have four humps, or body-wall outgrowths- two lateral, one postero-dorsal, and one posterior. The lateral outgrowths are normally collapsed and held against the sides of the body by a transverse muscle, but are popped out when the female withdraws her corona and creates positive pressure in her body cavity. Campanulates have a disproportionately broad corona compared to saccates and cruciforms. The three morphotypes differs greatly in their diet. The size of a prey organism that an A. sieboldi individuals can capture and eat is a direct function of the size of that individual. Since the three female morphotypes can be expressed by individuals derived parthenogenetically from a single female and hence have exactly the same genus, the control of morphotype expression is due entirely to the influence of environmental factors during development. Tocopherol seems to induce the relatively large cruciform and campanulate morphotypes by affecting a number of events which promote growth during development. Much of the information Gilbert have obtained on this subject was derived by comparing A. intermedia saccate and campanulate females, but it is likely that the same processes also occur in A. siebboldi. Tocopherol stimulates cytoplasmic growth, both prenatally and postnatally. (ref. ID; 2989)

    Measurements

    Resting egg diameter 197.6+/-1.5 µm (range 172.6-236.6 µm). (ref. ID; 773)

    1,600 µm female, trophi 220; 1,900 female, trophi 240; 2,000 female, trophi 340 µm. (ref. ID; 1834)

    Average length of specimens (female) 700 µm. Both mictic and amictic females were present, and the mictic females were smaller in length by about 100 µm. Average length of specimens (male) 300 µm. (ref. ID; 2385)

    Trophi 78 µm. (ref. ID; 2715)

    Asplanchna sieboldi urawaensis Sudzuki, 1956 (ref. ID; 1345, 3067, 3114)

    Descriptions

    Male: Male present. (ref. ID; 3067)

    Quote from ref. ID; 3067

    Locality

    Minoru Suzuki (1956) found in Japan (Urawa). (ref. ID; 1345)

    Asplanchna silvestri Daday, 1902 (ref. ID; 1923), silvestrii (ref. ID; 2285, 3218)

    Descriptions

    This species was first described by Daday in 1902, and found by him in plankton collections made by Dr. Sivestri in 1899 in the Lago di Villa Rica in Chile. Rousselet found Asplanchna silvestrii in the collections from Devils Lake, it presented a marked dimorphism, and even polymorphism, for all gradations from plain saccate forms to fully developed double-hamped animals. The jaws are of the usual type. The rami are massive, and have a semi-circular cut-out near the tip, which is peculiar; they have also a strong basal hook and median inner tooth. One of the rami, the one on the ring side when the basal hooks are uppermost, has a broad flange near its apical tooth this serves as a stop for the opposite tooth to prevent the two rami overlapping an interlocking. The prominent lateral humps differ markedly from those of other humped species. In A. silvestrii these are bifid, having a constriction, more or less pronounced above the middle of the hump, giving it a double rounded outline; on the dorsal side there is a pointed hump near the middle of the body. In intermediate forms the humps are less prominent until the purely saccate form is reached, which in shape does not much differ from that of A. brightwelli. The two gastric glands are large and kidney shaped, and are attached to the long and rather wide oesophagus. The stomach has the usual structure of large, dark coloured granulated cells. The ovary has the form of a narrow horseshoe-shaped band with a single row of germ cells. An enlarged view of one the lateral canals with the contractile vesicle. The flame cells are closely set and numerous, numbering over thirty; the fine tube to which they are attached adheres for some distance to the nerve-thread of the ventro-lateral antenna on each side. The sense organ consist of three pairs of antennae, namely two on the front of the head, two dorso-lateral and two ventro-lateral in position, each ending in a rocket-shaped organ with a tuft of stiff hairs on the outside. Two finger-like fleshy processes are seen, one on each side of the head close to the corona. Daday mentions that the animal has three red eyes, but Rousselet could discover only a single small cervical red eye, situated on the small brain. (ref. ID; 3218)
  • Male: Male present. It is humped, but the side humps are not bifid as in the humped female. (ref. ID; 3218)

    Comments

    The genus requires careful revision, as it is possible that the small changes in trophi and other characteristics on which species are based may be due to environment. (ref. ID; 2285)

    Measurements

    Total length 400 µm. (ref. ID; 2285)

    Greatest size of female 1,150 in length; male 408; jaws 164; resting egg 195 µm in diameter. (ref. ID; 3218)

    Asplanchna silvestris Daday, 1902 (ref. ID; 766, 1345)

    Descriptions

    This species is a very distinct species owing to its unique trophi. The ramus is massive and has a semicircular indentation near the tip, a large tooth protruding from the inner margin of the scapus (distal portion) of the ramus, and an apophysis on the bulla. The shape of the yolk gland nucleoli has not been described. The female is at least dimorphic and sometimes trimorphic. Females may be either saccate, cruciform- with large, lateral, bifid, body-wall outgrowths, or, campanulate. The male has two lateral body-wall outgrowths. (ref. ID; 766)