Psammonobiotus dziwnowi and Corythionella georgiana, Two New Freshwater Sand-dwelling Testate Amoebae (Rhizopoda: Filosea)

Kenneth H. Nicholls

《Acta Protozoologica》 44卷3期 (2005/09) Pp. 271-278

並列摘要

Two new species of the predominantly marine sand-dwelling testate rhizopod genera Psammonobiotus and Corythionella were discovered in sand beaches of the Canadian Laurentian Great Lakes. The most important differences between P. dziwnowi sp. n. its closest relative P. communis are (i) much smaller size of P. dziwnowi, (ii) greater length-to-width ratio in P. dziwnowi, (iii) greater angle of the plane of the oral aperture relative to the long axis of the test of P. dziwnowi. The only other known freshwater species of Corythionella, C. golemanskyi Nicholls, occurred together with C. georgiana sp. n. in samples from Wasaga Beach, Georgian Bay (Lake Huron) and enabled a direct comparison of test morphology of both populations occurring under the same environmental conditions. As well as a significantly smaller test size in C. georgiana, other differences with C. golemanskyi include smaller more elongate scales arranged in a more open non-overlapping pattern on the test surface of C. georgiana. Notwithstanding some uncertainties about the taxonomy of C. acolla, which is the only one of six marine species of Corythionella lacking a flared pseudostomal collar, the differences between it and C. georgiana, which has a minimally flared collar, include a generally shorter length, a much broader post-pseudostomal region and greater ratio of test width-to-pseudostome diameter in C. georgiana. These differences (ignoring, for the present, possible additional differences in the structure of the scale layer on the tests of C. georgiana and C. acolla), substantiate the designation of C. georgiana as an independent species.

並列關鍵字

Corythionella georgiana sp. n. ； Cyphoderiidae ； freshwater testate amoebae ； Psammonobiotidae ； Psammonobiotus dziwnowi sp. n. ； Testaceafilosia