Biodiversity, phylogeny and biogeography of the family Sphaeriidae (Mollusca: Bivalvia) in Morocco

• Main Author: Rassam, Hanane
• Other Authors: Wilke, Thomas, Ghamizi, Mohamed, El Alami El Moutaouakil, Majida, Himmi, Oumnia, Albrecht, Christian
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2024
• Subjects: Systematics; Distribution; Phylogeography; bivalves; freshwater; Morocco; ddc:570; Antarc*; Antarctica
• Online Access: https://jlupub.ub.uni-giessen.de//handle/jlupub/18808; https://doi.org/10.22029/jlupub-18172

The family Sphaeriidae Deshayes, 1855 is widely distributed across the globe, except for Antarctica, with a high species richness of up to 200 species. In Morocco, freshwater bivalves are receiving more and more attention in recent years and data on the families of this group are no longer a mystery for most of them. However, many uncertainties surround the current diversity and distribution of the family Sphaeriidae. This information, including taxonomy, phylogeography and conservation status, is essential for further studies to improve knowledge of this family in Morocco and represents the first step towards the development of a national conservation plan for all freshwater bivalves. In the present work, several investigations were carried out to evaluate the diversity and distribution of Sphaeriidae in the different basins of Morocco, covering different types of habitats (lakes, springs, rivers and small ponds) and microhabitats (mud, aquatic plants, etc). The identification of specimens and their morpho-ecological characteristics was based on morphological and morphometric analyses carefully processed to obtain maximum precision. Several studies have shown, however, the influence that environmental factors can have on the morphology of species, especially for species with a high morphological plasticity that can distort their identification. A case study was proposed for the species Pisidium casertanum, evaluating the intraspecific morphological variability according to the habitats of the species by the application of Fourier Elliptic Analysis, a geometric morphometric method analyzing the contour of the specimens. To complete the morpho-geometric analyses of the species and to confirm their identification, molecular analyses were carried out by integrating the sequences resulting from the amplification of four genes, mitochondrial (COI and 16S rRNA) and nuclear (H3 and 28S rRNA). These Moroccan sequences, complemented with other Pisidium sequences, were integrated to infer, for the first time, their ...