Taxonomic and Ecological Observations on Some Algal and Cyanobacterial Morphospecies New for or Rarely Recorded in Either Egypt or Africa

Abstract

The understanding of the diversity and spatial distribution of cyanoprokaryotes and algae in Egypt is challenging because this is still an understudied topic. To address this knowledge gap, we discuss morphotaxonomic features and ecological preferences for ten cyanobacterial and algal morphospecies from diverse Egyptian biotopes. Morphospecies were studied and identified using state-of-the-art and fine-grained taxonomy based on light and scanning electron microscope observations. Of these taxa, the cyanoprokaryotes Lemmermanniella uliginosa and Scytonema myochrous, the freshwater diatoms Cyclotella meduanae, Cavinula lapidosa, and Craticula subminuscula, the unicellular chrysophyte Mallomonas crassisquama, and the worldwide rarely-recorded zygnematalean streptophyte Hallasia cf. reticulata are designated as new records for Egypt. Moreover, the latter and L. uliginosa are as well first records for the whole African continent. Worthy of note, the freshwater diatoms Cyclostephanos invisitatus, Encyonema neomesianum, and Gomphonema laticollum have been rarely observed in previous Egyptian studies. Overall, most taxa identified tolerate increased nutrient concentrations (meso-eutraphentic and eutraphentic species), reflecting different human impacts on the biotopes they colonize. These newly recorded taxa are supposed to have been mostly overlooked in the previous Egyptian studies due to their relatively isolated habitats, small size, or complex taxonomic and nomenclatural history. More interesting algal and cyanobacterial taxa are still hidden and not yet discovered in Egypt, particularly in the little-explored and isolated desert habitats, and further research, using integrated polyphasic approaches, is therefore indispensable to achieve a better estimate of the Egyptian cyanobacterial and algal diversity, and to set up efficient algae-basedassessment systems tailored for the Egyptian habitats.