New araphid species of the genus Pseudostaurosira (Bacillariophyceae) from southern Patagonia.

GARCÍA M. LUJAN; BUSTOS, SABRINA; LEONARDO A. VILLACÍS; CECILIA LAPRIDA; PATRICIO I. MORENO; MAIDANA, NORA I.

EUROPEAN JOURNAL OF PHYCOLOGY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2021

0967-0262

We describe five new araphid diatom species belonging to the genus Pseudostaurosira.These new taxa were found in modern and fossil material collected from five southernPatagonian waterbodies (49º?52º S), four from the Santa Cruz province, Argentina and onefrom the Magallanes Region, Chile. When observed under light and scanning electronmicroscopy, each species differs by a single or a combination of valve character(s).Pseudostaurosira australopatagonica sp. nov. has unique volae that are profusely,dichotomously branched, internally anastomosed, and affixed to the virgae.Pseudostaurosira hyalopatagonica sp. nov. has fusiform valves with cuneate, elongateends, narrow valves and round to slightly elliptical areolae. Pseudostaurosira catalinae sp.nov. has broadly fusiform valves with cuneate to subrostrate ends; volae form a circular toelliptic ring at the center of the areolar opening and, externally covering the mantle areolae,it has a watch glass-like flap. Pseudostaurosira tehuelcheana sp. nov. has lanceolate valveswith broadly rounded apices, solid incipient conical spines and marginal, transapicallyelongate areolae occluded by profusely branched volae. Pseudostaurosira zolitschkae sp.nov. is a relatively large-valved species with subrostrate apices, hollow spines, marginalareolae sometimes separated by a thin vimen. The volae in this latter new taxon, onlyoriginate from a position parallel to the transapical axis of the valve, origin that isuncommon within the genus. We discuss the validity of describing species based onmorphological data and highlight the importance of increasing taxonomic resolution onisolated regions such as Patagonia.