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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Stephanoceros

Stephanoceros Ehrenberg, 1832

Synonym Coronella Goldfuss, 1820 (ref. ID; 3688)

ref. ID; 1663

Corona drawn out into long, pointed arms, which bear whorls of setae without cilia. In gelatinous tube. Foot terminate by a long, nonretractile peduncle, ending in an adhensive disc. (ref. ID; 1663)
  1. Stephanoceros eichhorni or eichhornii Ehrenberg, 1832
    See; Stephanoceros fimbriatus (ref. ID; 1345, 2757, 3688)
  2. Stephanoceros fimbriatus (Goldfuss, 1820) (ref. ID; 1345, 1821, 1923, 2757, 2827, 2918, 3688) reported year? (ref. ID; 3343) or Goldfusz, 1820 (ref. ID; 2703, 3335) reported year? (ref. ID; 2545, 2932)
    Syn; Coronella fimbriata Goldfuss, 1820 (ref. ID; 1345); Coronella fimbriatus Goldfuss, 1820 (ref. ID; 3688); Monolabis conica Ehrenberg, 1830 (ref. ID; 3688); Stephanoceros eichhorni Ehrenberg, 1832 (ref. ID; 1345); Stephanoceros eichhornii Ehrenberg, 1832 (ref. ID; 2757, 3688); Stephanoceros fimbriatus Montgomery, 1903 (ref. ID; 1345, 3688); Stephanoceros glacialis Perty, 1849 (ref. ID; 1345, 3688); Stephanoceros vulgaris Oken, 1835 (ref. ID; 1345, 3688); Stephanopus eichhornii Ehrenberg, 1832 (ref. ID; 2757)
  3. Stephanoceros glacialis Perty, 1849
    See; Stephanoceros fimbriatus (ref. ID; 1345, 3688)
  4. Stephanoceros horatii Cubitt, 1871
    See; Collotheca coronetta (ref. ID; 1345, 3271, 3688)
  5. Stephanoceros millsii Kellicott, 1885 (ref. ID; 1345, 2545, 2757, 4603) or 1895 (ref. ID; 2703)
    Syn; Floscularia millsii Kellicott, 1885 (ref. ID; 1345, 2757, 4603); Stephanoceros millsii Kellicott, 1886 (ref. ID; 1345)
  6. Stephanoceros vulgaris Oken, 1835
    See; Stephanoceros fimbriatus (ref. ID; 1345, 3688)

Stephanoceros fimbriatus (Goldfuss, 1820) (ref. ID; 1345, 1821, 1923, 2757, 2827, 2918, 3688) reported year? (ref. ID; 3343) or Goldfusz, 1820 (ref. ID; 2703, 3335) reported year? (ref. ID; 2545, 2932)

Synonym

Coronella fimbriata Goldfuss, 1820 (ref. ID; 1345); Coronella fimbriatus Goldfuss, 1820 (ref. ID; 3688); Monolabis conica Ehrenberg, 1830 (ref. ID; 3688); Stephanoceros eichhorni Ehrenberg, 1832 (ref. ID; 1345); Stephanoceros eichhornii Ehrenberg, 1832 (ref. ID; 2757, 3688); Stephanoceros fimbriatus Montgomery, 1903 (ref. ID; 1345, 3688); Stephanoceros glacialis Perty, 1849 (ref. ID; 1345, 3688); Stephanoceros vulgaris Oken, 1835 (ref. ID; 1345, 3688); Stephanopus eichhornii Ehrenberg, 1832 (ref. ID; 2757)

Descriptions

  • Egg: Newly deposited amictic eggs are dark, but they lighten during maturation. Before hatching, red eyespots as well as the ciliated corona and mastax may be distinguished. (ref. ID; 1821)
  • Larvae: Larvae have a long, worm-like body, divided into three regions: head, trunk, and foot. And they possess a circular wreath of relatively short cilia at the terminus of the head and of the foot. At the anterior end are two red eyespots set widely apart. The head is slightly broader than the trunk. Ganglion, a muscular mastax with well-developed trophi, two stomach glands, and a voluminous intestine are easily seen. These forms also possess red eyespots in the head region, but the lobes or arms of the adult animal are already present inserted inside of the head. Also visible is a large infundibulum, a vestibulum, a large mastax, and an intestine. An anus is usually visible, located in the middle part of the trunk. Larvae possess longitudinal hypodermal glands in the trunk. All internal organs usually obscured by abundant glandular inclusions. A dark oval formation which begins to brighten with the development of the larva is present. This body, which is probably identical to the anisotrophic (birefringent) crystalline structure (ACS) described by Wallace (1993), may function as an energy reserve for swimming and metamorphosis until the young animal begins feed. The foot is usually about 1/3 the total length of the body and contains two very prominent cement glands; the terminal part also contains small bladder-like glands. After constructing the basic tumbler the larvae withdraw into the short tube, remaining there without moving. When the young of these species complete this period of quietude, they extend from the tube and begin feeding and growing (including an increase in tube length). S. fimbriatus withdraws into its tumbler possessing the rounded shape of the larval corona; however, when it reappears it possesses the adult corona including the elongate arms. Development is apparently not complete even then; at first the coronal arms are curved or hooked, but soon they acquire the typical straight-armed shape. Therefore, the inactive period is actually one where developmental processes are very active. (ref. ID; 1821)

    Measurements

    Total length 1300; tube height 935; height at 1st egg 660; egg size 110x77; larval length 240-250 µm. (ref. ID; 1821)

    Length 1500 µm. (ref. ID; 3343)

    Stephanoceros millsii Kellicott, 1885 (ref. ID; 1345, 2545, 2757, 4603) or 1895 (ref. ID; 2703)

    Synonym

    Floscularia millsii Kellicott, 1885 (ref. ID; 1345, 2757, 4603); Stephanoceros millsii Kellicott, 1886 (ref. ID; 1345)

    Descriptions

    The animal is usually located in a wide, but not long gelatinous cover, never longer than half of the extended animal. The transparent gelatinous cover is built up of many layers. It seems that the rotifer periodically produced a gelatinous secretion and placed it on the inside of the whole cover. Every new layer on the inside is somewhat longer than the older one. The rotifer had a wide mouth cavity and a very large proventriculum. Mastax seemed very small in comparison with the size of the body of the animal. On the 5 vigorous tentacles the very long cilia were arranged in two parallel rows, placed laterally, but could be bent on the outside in diverse directions. The head was regularly and finely reticulated. The coronal margin between the tentacles was naked. (ref. ID; 4603)

    Comments

    The specimens from Sweden differ from Kellicott's animals by a shorter foot, which regularly continues over to a long, anteriorly somewhat enlarged body. The specimens by Kellicott have a long and slender foot, but short and thick body. Nor is the gelatinous cover like that of Swedish rotifers. In the gelatinous cover I often found parthenogenetic eggs together with zygotes. The later had a hard, obliquely striped shell. (ref. ID; 4603)