Ingolfiellidea (Crustacea, Malacostraca, Amphipoda): a phylogenetic and biogeographic analysis

The suborder Ingolfiellidea currently consists of 39 named species. An historical overview is presented and phylogenetic and biogeographic analyses are made. The result of the phylogenetic analysis suggests the definition of two new genera within an African freshwater group, namely Paraleleupia n. gen. and Proleleupia n. gen. Re-examination of a supposedly Italian relict species, Metaingolfiella mirabilis, with the aid of SEM techniques reveals a half-fusion of the head region with the first pereionite. The issue of the function of the ‘eyelobe’ is addressed and an explanation presented after examining with SEM such lobes in different species. Furthermore, additional descriptions are given based on the type-material of Metaingolfiella mirabilis, Trogloleleupia eggerti, Trogloleleupia leleupi, Ingolfiella littoralis, I. tabularis, I. margaritae, I. quadridentata, and I. abyssi. An attempt to relate the geographic distribution and ecological characteristics to the phylogeny of the Ingolfiellidea results in a paleogeographic scenario that points to a freshwater subterranean origin for the group that dates from at least Triassic times.