Typification and morphology of Staurosirella lapponica (Grunow) D.M.Williams & Round and Staurosirella pinnata var. intercedens (Grunow) P.B.Hamilton (Staurosiraceae, Bacillariophyta)

Authors

Van de Vijver B., Morales E.A., Schuster T.M., Wetzel C.E., Ector L.

Reference

Nova Hedwigia, vol. 115, n° 1-2, pp. 31-45, 2022

Description

For a long time, the identity of Staurosirella lapponica, originally described as Fragi-laria lapponica, was unclear as the original type material was never analysed in detail. Analysis of one of the samples used by Grunow to illustrate F. lapponica was investigated here by means of light and scanning electron microscopy. The observations allowed for a better morphological char-acterization of this species illustrating the ribbon-shaped colonies using bifurcated linking spines, its short striae on the valve face, and a reduced apical pore field. Additionally, a slide in the Cleve & Möller exsiccatae, bearing the type population of Fragilaria mutabilis var. intercedens, was likewise investigated to determine a possible conspecificity with S. lapponica. Based on our observations, it is clear that both taxa are conspecific, with F. mutabilis var. intercedens being a more recent heterotypic synonym of S. lapponica. Staurosirella lapponica is compared with all other el-liptic Staurosirella species. Only S. mutabilis shows some resemblance, but can be differentiated based on a higher stria density and larger apical pore field of the latter.

Link

doi:10.1127/nova_hedwigia/2022/0697