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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Amoenoscopa

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

Choanoflagellida: Family Acanthoecidae (ref. ID; 7106)

[ref. ID; 7106]
Diagnosis; Cell is solitary. The lorica is 19-23 um long (without stalk) and comprises anterior spines, a lorica chamber and a massive stalk. Anterior spines are 15-18 in number and are composed of 2 costal strips. The apical end of the anterior costal strip of the spine is trifurcated. The lorica chamber is composed of 20-26 longitudinal and 2-3 transverse costae. Each of the longitudinal costae is composed of one costal strip and they converge posteriorly onto the long massive stalk which is a bundle of 3-4 costal strips. Transverse costal strips connect on the inside of the lorica chamber and the base of the anterior spines. All the costal strips are thickend and elongated. (ref. ID; 7106)
Etymology; The generic name derived from the Latin amoeno, "beautiful" and scopa, "broom". (ref. ID; 7106)
Type species; Amoenoscopa caudata Hara & Takahashi, 1987 (ref. ID; 7106)
  1. Amoenoscopa caudata Hara & Takahashi, 1987 (ref. ID; 7106 original paper)

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

Diagnosis

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

Notes

In general, the form, dimensions and the structure of the lorica of Amoenoscopa n. gen., are similar to that of Polyoeca and/or Acanthoeca (cf. Leadbeater 1978; Hara & Takahashi 1984, Pl.I,3 in the present study). In these three genera, the champagne glass-like lorica are formed by anterior spines, a lorica chamber and a massive stalk, and the apical tips of the anterior spines are trifurcated (Pl.I,3,5) and the transverse costal strips are arranged on the inside of the anterior spines and the lorica chamber (Pl.I,4). The anterior spine structure, however, distinguishes Amoenoscopa clearly from Polyoeca and Acanthoeca, In Amoenoscopa n. gen., long and heavy costal strips constitute the anterior spines, that are connected by transverse costal strips only at its base (Pl.I,3). By contrast, anterior spines of Polyoeca and Acanthoeca are composed of both long and short spines, each of them is made up of delicate costal strips. Moreover, the spines of the latter two genera are backed by a band of regularly arranged transverse costal strips at the middle of the spines as well as the connection at the base (Leadbeater 1979; Hara & Takahashi 1984). Based on the heterogeneity of anterior spine structures between 'Amoenoscopa' and 'Polyoeca and Acanthoeca', it is justified to place Amoenoscopa in a separate genus in Acanthoecidae. On the other hand, Polyoeca and Acanthoeca are obviously closely related genera in the family because of the similarity of the anterior spine morphology (Leadbeater 1979; Hara & Takahashi 1984). In addition to Amoenoscopa caudata n. gen. & n. sp., four species, i.e. Acanthoeca spectabilis, Polyoeca dichotoma, Stephanoeca cauliculata, and Parvicorbicula pedunculata, have been shown to possess massive stalks (Leadbeater 1980; Hara & Takahashi 1984, Pl.I,3 in the present study). Although the morphological details of the massive stalks are different in these five species (Leadbeater 1980), a dense arrangement of longitudinal costal strips at the posterior half of the lorica (Pl.I,3,4), from where the massive stalk is projected, is a feature shared among these five species. This species may be eurythermal (the water temperature varied from 12.0 to 25.2 degrees C). (ref. ID; 7106)

Etymology

The specific name derived from the Latin caudata, "with a stalk". (ref. ID; 7106)

Iconotype

Plate I,3, collected from the surface water of the Shioya Coast on 4 August 1981, water temperature 25.2 degrees C. (ref. ID; 7106)