Diversity of Loxosceles spiders in Northwestern Africa and molecular support for cryptic species in the Loxosceles rufescens lineage

Abstract

Until recently, Loxosceles rufescens was the only species known from a geographic range including Northern Africa, Mediterranean Europe and the Middle East. Rich Loxosceles diversity in the New World suggests either that L. rufescens is a young lineage or that its diversity is underappreciated. We use a molecular phylogenetic and morphological approach to examine diversity in L. rufescens and other Loxosceles lineages in Northwestern Africa. Molecular analyses of one nuclear and two mitochondrial genes strongly support a monophyletic clade including L. rufescens, the Northern Brazilian L. amazonica and three other divergent Northwestern African lineages, though relationships among them remain unresolved. A genetically divergent Moroccan individual morphologically consistent with L. rufescens was strongly supported as sister to all other putative L. rufescens, consistent with the presence of at least 2 species in this lineage. COI p-distances and population structuring among remaining putative L. rufescens clades further suggest the absence of gene flow between clades and the possibility that they represent multiple species. Morphological characters of preserved Loxosceles collected in a range of African countries provide additional indication that Loxosceles are more diverse and have a deeper history in Africa than has been previously understood. © 2009 Elsevier Inc. All rights reserved.