Mediaria

From Frustule

GENUS Mediaria
Sheshukova-Poretskaya (1962)
Taxonomic Information Generitype: Mediaria splendida Sheshukova-Poretskaya, 1962 Genus Description: Frustula diagonaliter symmetrica. Valvae lanceolatae, marginibus in frustulis diagonaliter dispositis, incrassatis (carina). Structura valvae (extremitatibus exclusis) punctata, punctulis in seriebus transversis et longitudinalibus sub angulo recto se persecantibus. Area axilis deest. Areae triangulares juxta polos observantur. Genus monotypicum marinum fossile. [Translation]: Frustule diagonally symmetric. Valves lanceolate, the valve edges located in a frustule on a diagonal. Valve structure, except for its ends, in the form of correct cross-section and longitudinal numbers of the points crossed under a right angle. The axial field is not present; on poles triangular fields. Monotypic marine fossil genus.

List of Species belonging to the Genus Mediaria

General Remarks

Valva isopolari carinata necnon area axili nulla genus hoc a genere Trachysphenia Petit distat. Carinis in frustulis diagonaliter dispositis ad fam. Nitzschiaceae Hassal ut videtur pertinet. A genere Nitzschia Hassal structura valvae regulari, cancellos difractivos in mentem revocante et areis triangularibus juxta polos dispositis differt. Genus novum, ut videtur, locum medium inter Aulonoraphineae (genus Nitzschia Hassal) et Diraphineae (genus Tropidoneis Cleve) tenet.

[Translation]: Isopolar valve, presence of Kiel and absence of an axial zero distinguish a new genus from genus Trachysphenia Petit (Jousé, 1959, pl. 4, fig. 1). Position of Kiel in a frustule allows to carry presumably it to this. Nitzschiaceae Hassal. From genus Nitzschia Hassal it differs structure of a valve of type дифракционной lattices and triangular fields at poles and is, apparently, a link between Aulonoraphineae (genus Nitzschia Hassal) and Diraphineae (genus Tropidoneis Cleve).

Useful References

• Sheshukova-Poretzkaya, V.S., 1962. New and rare Bacillariophyta from the diatom suite of north Sakhalin. Uchenyye Zapiski, Seriya Biologicheskii Nauk, Leningrad State University, Biological Institute, 49(313):203-211 [in Russian and Latin].