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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Campyloacantha

Campyloacantha Hara & Takahashi, 1987 (ref. ID; 7106 original paper)

Choanoflagellida: Family Acanthoecidae (ref. ID; 7106)

[ref. ID; 7106]
Diagnosis; Cell is solitary. The lorica is composed of anterior spines, a lorica chamber and a posterior spine. Anterior spines are 3-5 in number, each of which is 6-8 um long and is composed of 1 costal strip. The conical lorica chamber is 10-11 um long and comprises 8 longitudinal and 1 transverse costae. The longitudinal costa is composed of two successive costal strips. The short anterior costal strips converge posteriorly in groups of 2-3 onto the front ends of the three long posterior costal strips, which converge at te posterior end of the lorica chamber. The transverse costal comprises 3-5 costal strips, and clockwise ends (viewed from anterior) of the transverse costal strips fuse with the posterior ends of the anterior spines each. Another ends of the transverse costal strips bent down obliquely to attach firmly to the bases of the anterior spines. (ref. ID; 7106)
Etymology; The generic name derived from the Greek campylo, "curved", and acantha, "spine". (ref. ID; 7106)
Type species; Campyloacantha imbricata (ref. ID; 7106)
  1. Campyloacantha imbricata Hara & Takahashi, 1987 (ref. ID; 7106 original paper)
  2. Campyloacantha spinifera (Leadbeater) n. comb. (ref. ID; 7106 redescribed paper)
    Syn; Parvicorbicula spinifera Leadbeater, 1973, p.245, fig.2c (ref. ID; 7106)

Campyloacantha imbricata Hara & Takahashi, 1987 (ref. ID; 7106 original paper)

Diagnosis

The species diagnosis is identical to the generic diagnosis. (ref. ID; 7106)

Notes

Calliacantha Leadbeater (Leadbeater 1978) is closely related to Campyloacantha in having the conical lorica chamber, in the small number of the longitudinal costae and in the structures of the anterior and posterior spines each of which is formed by one bristle costal strip. In fact, the general form of C. imbricata n. gen. & n. sp. is very similar to that of C. natans (Grontved) (Manton & Leadbeater 1978, Pl.I, 1 in the present study). This two genera, however, can be distinguished clearly by the following characteristics: costal strips forming anterior spine and transverse costa are connected but not fused in Calliacantha, while in Campyloacantha these costal strips are fused end to end and consequently form "L" shaped costal strips (Pl.I, 1-2). Another important difference is that the length of longitudinal costal strips are nearly equal in Calliacantha, but different in Campyloacantha. In the latter genus, the anterior one is about half in length of the posterior one. (Pl.I, 1). These characteristics not only set Campyloacantha apart from Calliacantha, but also distinguishes this new genus from all the other genera of the family Acanthoecidae. (ref. ID; 7106)

Etymology

The specific name derived from the Latin imbricata, "imbricated". (ref. ID; 7106)

Iconotype

Plate I, 1, collected from the surface water near the Shioya Coast, water temperature 15 degrees C. (ref. ID; 7106)

Campyloacantha spinifera (Leadbeater) n. comb. (ref. ID; 7106 redescribed paper)

Synonym

Parvicorbicula spinifera Leadbeater, 1973, p.245, fig.2c (ref. ID; 7106)

Descriptions

The general lorica structure of Parvicorbicula spinifera described by Leadbeater (1973, fig.2c, pl.15c,d) is quite similar to that of Campyloacantha imbricata n. gen. & n. sp. Particularly, the base of an anterior spine of P. spinifera apparently sticks firm on one end of a transverse costal strip and consequently they form a "L" shaped anterior costal strip. Judging from the photographs in Leadbeater (1973, pl.15c,d), the longitudinal costa consists of two costal strips and the anterior one is shorter than the posterior one. Additionally, both species have one conical lorica chamber that is composed of one transverse costa and some longitudinal costae which converge at the posterior ends of the lorica chambers. Based on the close similarity mentioned above in the structures of the loricae between C. imbricata n. gen. & n. sp. and P. spinifera, it is reasonable to include these two species in a same genus, Campyloacantha. These two species, however, differ as regards: (1) the number of anterior spines is 3-5 in C. imbricata, as compared to 6 in P. spinifera, (2) the general shape of the lorica chamber is long conical in C. imbricata, compared to short conical in P. spinifera, and (3) the height of the lorica is more than 16 um (without posterior spine) in C. imbricata, while it is only 8 um in P. spinifera. The existence of posterior spine is not clear in P. spinifera. It thus seems justified to transfer P. spinifera to a separate species in the new genus Campyloacantha. (ref. ID; 7106)