Guarreraea Kociolek, Guerrero et Van de Vijver

Guerrero, J. M., A. A. Vouilloud, Sala, S. E., Kociolek, J. P. & Vijver, B. Van De, 2018, New species and a new genus of the Orthoseirales from Patagonia, Argentina, with comments on systematic affinities within the Order, Phytotaxa 345 (2), pp. 119-132 : 129

Genus Guarreraea Kociolek, Guerrero et Van de Vijver

Description: —Cells cylindrical in girdle view, attached through small linking spines. Valve face disc-shaped, flat or slightly sunken, forming a right angle with valve mantle. Striae uniseriate, radiate, leaving a small hyaline area at or near the valve center. External valve face rather rough, occasionally with small spinules between the areolae, internal surface smooth. Poroid areolae round or slightly elliptical. Central area with a ring of numerous (up to 14) carinoportulae. Small rimoportulae with more or less developed internal and external openings, alternating or within the ring of carinoportulae. Valve mantle striae parallel to pervalvar axis composed of small areolae. Lower part of mantle, or collum, unornamented, internally thickened. Cingulum comprising several open copulae. Each girdle band with a hyaline zone on both edges and irregularly arranged round areolae. A relatively large ligula fitting on a slit or anti-ligula of adjacent copula.

The presence of carinoportulae in the new genus justifies its inclusion within the Order Orthoseirales . Guarreraea can be distinguished from Orthoseira by the presence of small carinoportulae, rimoportulae and the absence of caverns and internal valves.

Etymology: —named in honor of Dr. Sebastián A. Guarrera, a pioneer in phycological studies in Argentina and South America.

Generitype: Guarreraea limnopolarensis (Van de Vijver & Crawford) Kociolek & Van de Vijver comb. nov.

Basionym: Orthoseira limnopolarensis Van de Vijver & Crawford 2014 , Orthoseira limnopolarensis sp. nov. (Bacillariophyta), a new diatom species from Livingston Island (South Shetland Islands, Antarctica). Cryptogamie Algologie 35(3): 248, figs 1–14.