Main Content
< Top page

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Protaspis

Protaspis Skuja, 1939 (ref. ID; 4907, 4950)

Order Thaumatomastigidae nom. nov. (ref. ID; 4872) or Poche, 1913 (ref. ID; 4907)

[ref. ID; 4907]
Gliding cells with a more or less well developed ventral furrow, no scales visible by light microscopy. Vors (1992) notes that the cells are often filled with particles of different colour derived from food. Genus erected by Skuja (1939) for P. glans, P. major and P. metarhiza. One species, P. obovota, added by Skuja (1948), four more (P. gemmifera, P. obliqua, P. tegere, and P. verrucosa) by Larsen & Patterson (1990), and one, P. simplex by Vors (1992). (ref. ID; 4907)

[ref. ID; 7130]
Protaspis and three species were validly described under the International Code of Botanical Nomenclature (ICBN) by Skuja (1939) as was his later (fourth) species (Skuja 1948), but the genus name is invalid under the International Code for Zoological Nomenclature (ICZN) as it was preoccupied by the Devonian fish Protaspis Bryant, 1933 (family Protaspididae), yet since Cavalier-Smith (1993) it has been treated under the ICZN (ICZN, now used for all Cercozoa). The species names of Larsen and Patterson (1990) were described under both codes but are valid only under ICBN. All subsequently described species names (Hoppenrath and Leander 2006; Chantangsi and Leander 2010) are illegitimate under ICBN as they lacked Latin diagnoses, and invalid (like those of Larsen and Patterson 1990) under ICZN as junior synonyms of Protaspis Bryant. Since the root of Protaspis is protaspid- the protists zoological family name (Cavalier-Smith 1993) ought to have been Protaspididiae; to allow continued use of a zoological generic name very close to Skuja's Protaspis, to validate all existing species names under ICZN, and to retain Protaspidae as the valid family name we propse Protaspa as a replacement name for Protaspis Skuja (1939) under ICZN and make 14 new comibinations: We also formally transfer Protaspidae from Thaumatomonadida (Cavalier-Smith 1993) to Cryomonadida and place Cryothecomonas in it. In view of evidence that Protaspa and Cryothecomonas are very similiar morphologically and rather closely related genetically (Hoppenrath & Leander 2006), we not longer need the separate family Cryothecomonadidae Cavalier-Smith, 1993, here regarded as a junior synonym of Protaspidae by virtue of its being later in the paper that initiated both names (Cavalier-Smith 1993) and Protaspa being discovered before Cryothecomonas. (ref. ID; 7130)
  1. Protaspis gemmifera Larsen & Patterson, 1990 (ref. ID; 4907)
  2. Protaspis glans Skuja, 1939 (ref. ID; 4907) reported year? (ref. ID; 4950)
  3. Protaspis major Skuja, 1939 (ref. ID; 4907) reported year? (ref. ID; 4950)
  4. Protaspis metarhiza Skuja, 1939 (ref. ID; 4907) reported year? (ref. ID; 4950)
  5. Protaspis obliqua Larsen & Patterson, 1990 (ref. ID; 4907)
  6. Protaspis obovata Skuja, 1948 (ref. ID; 4907) reported year? (ref. ID; 3517, 4950)
  7. Protaspis simpex Vors, 1992 (ref. ID; 4907)
  8. Protaspis tegere Larsen & Patterson, 1990 (ref. ID; 4872, 4907)
  9. Protaspis verrucosa Larsen & Patterson, 1990 (ref. ID; 4907)

Protaspis simpex Vors, 1992 (ref. ID; 4907)

Descriptions

Cell ovate, slightly dorso-ventrally flattened, somewhat irregular in outline, anterior end obliquely truncate, left side of cell slightly longer than right, length/breadth ratio about 1.5-1.7. Two slightly acronematic, heterodynamic flagella emerge from a weakly developed ventral groove. Anterior flagellum about half as long as cell, posterior flagellum 2 to 2.5 times cell length. Nucleus in anterior end of cell. Cytoplasm usually filled with coloured granules as observed by Vors (1992). Cells glide along substrate with a wobbling motion, posterior flagellum trails along substrate. Body-trailing flagellum angle about 45 degrees. Anterior flagellum beats in a regular fashion, beat envelope encompasses an angle of about 45 degrees, beat angle oblique, directed towards left side of cell. Ventral pseudopodia not observed. (ref. ID; 4907)

Comments

The organism described above is in good agreement with Protaspis simplex as described by Vors (1992). Vors did not state explicitly that the anterior of the cells is obliquely trancated, but this is seen from her figure (Vors 1992, fig.45: 1, 2). Protaspis simplex differs from other species of Protaspis by its small size, its weakly developed ventral groove, the absence of a wartly surface (P. verrucosa Larsen & Patterson, 1990), and by its nucleus morphology. Protaspis simplex has a superficial resemblance to Heteromita globosa, but H. globosa has a more rounded body and a more irregular flagellar beat without an oblique beat angle. Heteromita globosa tends to be smaller than P. simplex, and the cytoplasm of H. globosa is not filled with coloured granules. Heteromita globosa sometimes forms pseudopodia from the anterior end, while Protaspis occasionally form pseudopodia from ventral surface. (ref. ID; 4907)

Measurements

Length 4.5-9 um. (ref. ID; 4907)

Protaspis tegere Larsen & Patterson, 1990 (ref. ID; 4872, 4907)

Descriptions

Cell 18 um long, oblong with truncated ends, slightly flattened. One ventral groove, surface with granules or wart-like markings. Nucleus spherical, with cap-like structure, located in the anterior part of the cell. Two unequal flagella. Anterior flagellum about cell length inserting subapically in a slight depression. Posterior flagellum 1.5-2 times cell length, slightly thicker, inserting just posterior to anterior flagellum. Cytoplasm may have refractile globules, especially at anterior end. Moves by gliding. (ref. ID; 4872)

Remarks

The recorded cells are in agreement with the original description of P. tegere (Larsen & Patterson, 1990), except for the surface texture which is not mentioned in the verbal description, but inclusions may be seen in the photographs. (ref. ID; 4872)