Rise of subgen. Rhoicosphenula Lange-Bert. to the genus level, and description of a new Gomphosphenia s. s. species from Puerto Rico Author Saber, Abdullah A. Botany Department, Faculty of Science, Ain Shams University, Abbassia Square, Cairo 11566 (Egypt) and MUSE - Museo delle Scienze, Limnology and Phycology Section, Corso del Lavoro e della Scienza 3, 38123 Trento (Italy) Author Angeli, Nicola MUSE - Museo delle Scienze, Limnology & Phycology Section, Corso del Lavoro e della Scienza 3, I- 38123 Trento (Italy) Author Lange-Bertalot, Horst Goethe Universität Frankfurt, Biologicum, Max-von-Laue Straβe 13, 60438 Frankfurt (Germany) Author Kociolek, John P. Museum of Natural History and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309 (United States) Author Spitale, Daniel MUSE - Museo delle Scienze, Limnology & Phycology Section, Corso del Lavoro e della Scienza 3, I- 38123 Trento (Italy) Author Charles, Donald F. Patrick Center for Environmental Research, Academy of Natural Sciences of Drexel University, Philadelphia, PA 19103 (United States) Author Cantonati, Marco MUSE - Museo delle Scienze, Limnology & Phycology Section, Corso del Lavoro e della Scienza 3, I- 38123 Trento (Italy) and Patrick Center for Environmental Research, Academy of Natural Sciences of Drexel University, Philadelphia, PA 19103 (United States) marco. cantonati @ muse. it (corresponding author) cantonati@muse.it text Cryptogamie, Algologie 2021 2021-09-29 20 13 217 229 http://dx.doi.org/10.5252/cryptogamie-algologie2021v42a13 journal article 245033 10.5252/cryptogamie-algologie2021v42a13 82ddef57-2a25-4cce-b92c-cbc85f507f07 1776-0992 7819267

TABLE 2. — Comparison of key features distinguishing the genera Gomphosphenia sensu stricto and Rhoicosphenula as defined in this study.

	Gomphosphenia sensu stricto	Rhoicosphenula stat. nov.
Main reference	this study	this study
Frustules’ girdle view	typically wedge-shaped	almost rectangular
Septa	absent	conspicuous: copulae with septa at one of the poles
Pseudosepta	absent (faintly developed at the headpole in some	distinctive at both valve poles
species?)
Terminal raphe fissures (external)	teardrop-shaped pores	T-shaped
Proximal raphe fissures (internal)	usually T-shaped	short and very faintly bent
Habitat	medium-conductivity, alkaline inland waters	acidic and dystrophic