Morphology and phylogeny of the testate amoebae Euglypha bryophila Brown, 1911 and Euglypha cristata Leidy, 1874 (Rhizaria, Euglyphida).

The genus Euglypha contains the largest number of filose testate amoeba taxa which were mainly described based on the morphological characteristics of shells. Despite the increasing amount of molecular data, the phylogenetic relationships within the genus Euglypha remain unresolved. In this work we provide new data on SSU rRNA gene sequences, light and electron microscopy for the two euglyphid species Euglypha bryophilaBrown, 1911 and Euglypha cristataLeidy, 1874. Both species are characterised by the presence of a turf of spines on the aboral pole of the shells but differ in shell cross sections (elliptical and circular, respectively). A newly revealed feature of E. bryophila is a three-lobed thickening at the anterior margin and an elongated lobe at the posterior margin of apertural plates. The phylogenetic analysis shows that the species group together with the previously sequenced taxa of the genus Euglypha according to the shell cross-section. The subdivision of the genus based on the shell symmetry may reflect evolutionary trends to complication of the shell from radial to biradial symmetry. We also suggest that the shape of the anterior thickening of apertural plates and the lobe at the posterior margin can be used to distinguish Euglypha at the species level.

Cryptic diversity within the choanoflagellate morphospecies complex Codosiga botrytis - phylogeny and morphology of ancient and modern isolates.

Choanoflagellates are closely related to metazoans and fungi according to recent phylogenetic studies; therefore the systematics of these organisms is of particular interest. The choanoflagellate morphospecies Codosiga botrytis is the first described choanoflagellate, and is one of the most frequently reported choanoflagellate species. In this study we present phylogenetic and morphological data on eight different strains of Codosiga botrytis. Among these there are five ancient strains; these cultures have been established from up to 43,000 years old cysts from Siberian permafrost. We found that based on the variable V4 region of the small subunit (SSU) of the rDNA, all the investigated freshwater isolates of Codosiga botrytis, together with Sphaeroeca volvox, form a cluster at the base of all other choanoflagellate species. Moreover, the morphospecies described classically as Codosiga botrytis contains at least four different genotypes separated by considerably high genetic distance. All these 'cryptic species' have identical general morphology and cell structure. Strains have a similar life cycle with several different life forms and large morphological plasticity. For the first time we were able to establish cultures from cryo-conserved cysts of choanoflagellates. The ancient strains did not differ significantly in partial SSU rDNA from the modern ones. Besides, no biogeographically pattern could be established. This fact and the low genetic distances of some strains from remote locations support the distribution of dormant stages via air.