ISSN:
1550-7408
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
. Psilotricha acuminata was described by Stein in 1859 as the type species of the ciliate genus PsilotrichaStein, 1859. The ciliate has rarely been found since, and its infraciliature has never been described with the aid of silver-impregnation techniques. We have found P. acuminataStein, 1859 in soil samples from upland grassland in Scotland (U.K.). Living and healthy organisms of P. acuminata are oblong in outline, and dorso-ventrally compressed. They closely resemble ciliates of the genus Euplotes. The main morphological features used for identification of P. acuminata are the very long and sparse cirri, and the two macronuclei. When the ciliate crawls, the cirri appear stiff and directed backwards. Specimens observed from the ventral side have a protruding anterior end. a rounded or acuminate posterior pole, and a “beak-like” projection to the left side of the posterior end. The ciliate shares characters with the Euplotidae (body shape and reduced ciliature) and with the Oxytrichidae (marginal rows, macronuclei, reduced number of transverse cirri). Because the arrangement of the silver-impregnated infraciliature was unknown, and as the only description of the ciliate was that of Stein (1859a, b), the genus Psilotricha became confused with other hypotrich genera, especially UrospinulaCorliss, 1960. Here we provide a full redescription of P. acuminata based on living and silver-impregnated specimens, and a revision of the genera PsilotrichaStein, 1859 and UrospinulaCorliss, 1960. We resurrect the genus Urospinula, and give an emended diagnosis for both genera. The species now included within the genus Psilotricha are P. acuminataStein, 1859 (type species); Psilotricha viridis (Penard, 1922) Kahl, 1932; and Psilotricha geleii (Gelei, 1954) Stiller, 1974. Psilotricha viridis sensu Kahl, 1932 and Psilotricha dragescoiGrolière, 1975 are considered incertae sedis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1550-7408.2001.tb00316.x
