Isopoda (crustacea) from the Levantine sea with comments on the biogeography of mediterranean isopods

Abstract

This study focuses on the isopod fauna of the eastern Mediterranean, mainly from the waters of Lebanon. Ninety-five samples containing isopods were obtained by scuba diving (depths 0 to 44 m) at 32 stations along the coast of Northern Cyprus, Syria, and Lebanon. The substrates most frequently sampled were caves, vertical walls, and calcareous algae crusts or build-ups. A total of 502 individuals were studied, belonging to 28 species, included in 20 genera, nine families, and three suborders. Four new species from this collection (Atarbolana beirutensis, Cirolana bitari, Cirolana zibrowiusi, Mesanthura pacoi) have already been published. Brief diagnoses and illustrations were included. The collection studied here consists mostly of Mediterranean species, some already known in the area. Ten (eleven, when cf. species is confirmed) are new records in the Levantine Sea (Apanthura addui, Cirolana manorae, Cymodoce fuscina, Cymodoce pilosa, Elaphognathia bacescoi, Gnathia illepidus, Gnathia inopinata, Heptanthura cryptobia, Kupellonura serritelson, Metacirolana rotunda, Pseudocerceis cf. seleneides). Of them, three (four, when cf. species is confirmed) are new records in the Mediterranean Sea (Apanthura addui, Cirolana manorae, Metacirolana rotunda, Pseudocerceis cf. seleneides). Eight species (28.5%) can be considered as non-indigenous (Apanthura addui, Cirolana manorae, Cymodoce fuscina, Metacirolana rotunda, Paracerceis sculpta, Paradella dianae, Pseudocerceis cf. seleneides, Sphaeroma walkeri). This manuscript also provides an inventory of the known Mediterranean isopod fauna (excluding Epicaridea, Oniscidea, and brackish water Aselloidea), which totals 295 species. The isopod fauna of various subregions of the Mediterranean, the Suez Canal, and the Red Sea / Gulf of Aden is compared, and the transit of species through the Suez Canal is discussed. The list of non-indigenous species in the Mediterranaean Sea is updated to 23.

Low diversity or poorly explored? Mesophotic molluscs highlight undersampling in the Eastern Mediterranean

“…However, part of the reported lower diversity in the Eastern Mediterranean may be attributed to insufficient sampling: every time a taxonomic group is thoroughly studied, a remarkable number of previously unreported native species is recorded (e.g. Morri et al 2009;Idan et al 2018;Crocetta et al 2020;Achilleos et al 2020;Castelló et al 2020). Our results are no exception: the 43 newly reported species constitute an increase of 7% in relation to the 624 native molluscs previously recorded from Israel.…”

Inventory and Geographical Affinities of Algerian Cumacea, Isopoda, Mysida, Lophogastrida and Tanaidacea (Crustacea Peracarida)

“…To assign the status of Non-Indigenous Species (NIS) to certain species found in Algerian waters, we based ourselves on the work of [78][79][80][81]. Castelló et al [10] studied the distribution of isopods from the Mediterranean biogeographical sub-regions and the Red Sea; in their study, they identified "Lessepsian species" and "anti-Lessepsian species". The term "Lessepsian" (L) is applied, according to [82], to species crossing the Suez Canal by their own means and reaching the Mediterranean Sea.…”

“…Por [82] also used the term "anti-Lessepsian" (Anti-L) for species that follow a path opposite to Lessepsians. For the identification of "Lessepsian species" and "anti-Lessepsian species" from the Algerian coast, we refer to the studies of these authors [10,[78][79][80][81].…”

“…Nevertheless, numerous publications report inventories at local, national and regional scales for the Mediterranean Sea and have notably contributed to our knowledge of Peracarid groups (see [1], for references before 2008). Some inventories cover the entire Mediterranean Sea [7][8][9][10], while others are limited to certain areas: the Alboran Sea [11][12][13][14], the Mediterranean coasts of Spain [9,[15][16][17][18][19][20][21] and France [22,23], Italian waters [24][25][26][27][28][29], the Adriatic Sea [30], as well as the coasts of Tunisia [31][32][33][34][35][36][37][38][39][40], Malta [41], Libya [42], Greece [43][44][45], Turkey [46][47][48][49][50], the Levantine Sea [10,…”

“…Thus, publications over the last decade have contributed to an increased knowledge of the diversity of Peracarida. For example, Coll et al [1] estimated the isopod diversity at 165 species, ten years later this diversity was evaluated at 295 species [10].…”