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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Pseudonotholca

Pseudonotholca Marukawa, 1928

ref. ID; 2285

The question of the validity of the genus Pseudonotholca is thoroughly discussed by Berzins (1951); and I agree with his views that if Argonotholca folicea is to be separated from Notholca the same action must be taken with Pseudonotholca japonica. It may be, as Berzins states, that if the genus Notholca is carefully revised it will be possible to include both Argonotholca and Pseudonotholca. (ref. ID; 2285)

ref. ID; 3509

Carlins' (1943) point of view is that genus Notholca may be divided into three typical groups. The first group would contain Notholca foliacea Ehrenberg which has adequately distinctive structural characteristics to form a separate genus. This idea has been realized few years later by Gillard (1948) who formed for this species a new genus - Argonotholca. Carlin further points out that it is rather closely attached to Pseudonotholca japonica Marukawa. Yet the latter differs sufficiently and should retain its place in a separate genus. This consideration is, however, doubted by Gillard (also by Hada) and he classifies this species in a separate section in the genus Notholca. Carlin observed a certain similarity of P. japonica with Notholca cornuta Carlin which nevertheless remains in the fundamental group Notholca with the rest of the species of this genus. Comparing Argonotholca foliacea (Ehrenberg) and Pseudonotholca japonica Marukawa with the species we observe in both these species a certain similarity in the structure of the ventral plates, which differs from the plates of all other species in genus Notholca. While in the case of Argonotholca the ventral side abdominally forms a rudder-like plate in the case of Pseudonotholca it remains flat but is in a characteristic way separated from the dorsal side. The facets on the dorsal lorica of Argonotholca are typical of Argonotholca in the same degree as the 4 occipital spines are a distinctive mark for Pseudonotholca. In my opinion, if we continue to recognize the genus Argonotholca, we have to maintain also the genus Pseudonotholca, especially referring to the ecologically important circumstance that this is a typical form of salt-water plankton the like of which has not been observed in the genus Notholca. An exact conclusion in the matter considering the relations and classification of Notholca and the relative genera may be established only after a careful examination of the interesting and rather peculiarly constructed species (e.g. Notholca baicalensis, olchonensis, triarthroides etc.) for which at present we have no sufficient fair descriptions. Actually there exists a possibility that after a careful revision of all the known genera and species they might all be placed back into one - the genus Notholca. (ref. ID; 3509)
  1. Pseudonotholca japonica Marukawa, 1928 (ref. ID; 1345, 3509, 4594) reported year? (ref. ID; 3573)
    Syn; Notholca bifurca Hada, 1939 (ref. ID; 3509); Notholca japonica Gillard, 1948 (ref. ID; 3509); Notholca quadrispinata Myers, 1936 (ref. ID; 3509)
  2. Pseudonotholca pacifica Russell (ref. ID; 2285 original paper) reported author and year? (ref. ID; 1709)

Pseudonotholca japonica Marukawa, 1928 (ref. ID; 1345, 3509, 4594) reported year? (ref. ID; 3573)

Synonym

Notholca bifurca Hada, 1939 (ref. ID; 3509); Notholca japonica Gillard, 1948 (ref. ID; 3509); Notholca quadrispinata Myers, 1936 (ref. ID; 3509)

Descriptions

Marine species. (ref. ID; 3573)

Body dorso-ventrally flattened. Dorsal lorica larger than ventral, with four spines in front and ending posteriorly in two spines. A membranous cuticle joins ventral and dorsal plate together. Oceanic, planktonic species. (ref. ID; 4594)

Measurements

Total length 230-235; width of lorica 90-96; depth of lorica 70-75; length of antero-intermediate spines 28-30; length of antero-lateral spine 18-24; length of posterior spines 21-25 µm. (ref. ID; 3509)

Total length 220-250 µm. (ref. ID; 4594)

Pseudonotholca pacifica Russell (ref. ID; 2285 original paper) reported author and year? (ref. ID; 1709)

Descriptions

The body is ovate and has four sharp, extremely thin anterior dorsal spines the medians being the longest. Posteriorly the body is broadly rounded, but in some preserved material may come to a very blunt and obscure point. The ventral section is truncate anteriorly, and broadly pointed posteriorly, where it makes an acute angle with the dorsal plate. There are no folds on the body except for four short longitudinal ridges proceeding down the dorsal plate from the anterior spines. (ref. ID; 2285)

Comments

This is apparently only the type second species of the genus recorded, and differs in many respect from Pseudonotholca japonica. The anterior spines are different in shape, and there is no posterior furcate projection. The posterior longitudinal ridges, and the anterior pustulation of the dorsal plate found on japonica are absent. In lateral view the two species are similar in the ventral section, and both have four anterior spines. In some views the new species appears to have six spines. This is an illusion, and is caused by the anterior lateral edges of the dorsal plate. There are only four spines. (ref. ID; 2285)

Measurements

Length of body 190; greatest width 120; length of median spines 20; length of outer spines 15 µm. (ref. ID; 2285)