Porosia Jung 1942

Anatoly BOBROV & Anush KOSAKYAN, 2015, A New Species from Mountain Forest Soils in Japan: Porosia paracarinata sp. nov., and Taxonomic Concept of the Genus Porosia Jung, 1942, Acta-Protozoologica 54, pp. 289-294 : 294

Taxonomic concept of genus Porosia Jung 1942

Since the genus Porosia is not monospecific anymore, an expansion of the concept of this genus is required.

Original description of the genus according to Jung 1942 is the following:

Ahnlich wie Penardiella mit Porendurchbohrungen am Halsansatz. Doch fehlen die Porenlochgruppen in der Nahe des Pseudostoms. Rein boreal mit nur einer Art: P. bigibbosa (Penard, 1890) , die sehr selten in Europe, dagegen in Spitzbergen haufiger ist. Vielleicht kaltstenotherm? Schalenende breitgerundet. l = 135– 170 u, br = 87–110 u, m = 34–35 u.

Translation: Similar to Penardiella [currently Certesella ] with pore holes on the base of the neck. However the pore punctuations on the base of the neck near aperture is lacking. Purely boreal with only one species P. bigibbosa (Penard 1890) , in Europe very rare, but more prevalent in Spitzbergen [currently Svalbard, Norway]. Maybe cold-stenothermic? Posterior end of the test is broadly rounded, length 135–170 µm, breadth 87–110 µm, aperture 34–35 µm wide.

Expansion of the taxonomic concept for the genus Porosia (Jung 1942) sensu Bobrov et Kosakyan:

Test is pyriform, with rounded posterior end, laterally compressed. In front view two distinct lateral depressions with two large invaginated pores are situated on each side, which are connected by internal tubes as in genus Certesella . In profile, small lateral pores can be observed, just anterior to the large pores. The lateral keel can (or can not) be present surrounding 1 / 3 of posterior lateral margin (keel is important distinctive character between Porosia species: Porosia bigibbosa – lacking of lateral keel, Porosia paracarinata – presence of lateral keel). Test composed of euglyphid shell plates embedded in unstructured cement. Aperture is curved, surrounded with organic lip.

Habitat: sphagnum mosses, litter, soil, rare genus.

This genus is closely related to Certesella but lacks the punctuated neck.