First Northwest African species of the spider genus Artema, from caves in Morocco, with notes on body size in pholcid spiders (Araneae: Pholcidae)

The genus Artema Walckenaer, 1837 includes some of the largest pholcid spiders and is geographically largely restricted to Central Asia, the Middle East, the Arabian Peninsula, and the eastern Mediterranean. One species has previously been known from West Africa. The first known Moroccan species, A. martensi sp. n., extends the known distribution of the genus to the northwestern limit of the African continent. The species is described from two caves in the western Anti-Atlas, but it is not troglomorphic. A comparative analysis of male carapace width in 1632 pholcid species shows that A. martensi sp. n. is the largest known pholcid with respect to this character. Plots of mean carapace sizes of newly described species on periods of time (50 years, 20 years) show that the mean sizes of newly described species have been constantly decreasing.