Systematics of the Genus Dysdera (Araneae, Dysderidae) in the Eastern Canary Islands

Abstract

The circum-Mediterranean spider genus Dysdera has undergone an outsanding species radiation in the volcanic archipelago of the Canary Islands. The present study deals with the endemic species that inhabit the older and ecologically distinct islands of Fuerteventura, Lanzarote and their nearby islets. A new species, Dysdera sanborondon, is described. The male of D. spinidorsum Wunderlich 1991, is described for the first time. Five species are redescribed: D. alegranzaensis Wunderlich 1991; D. Iancerotensis Simon 1907; D. longa Wunderlich 1991; D. nesiotes Simon 1907, and D. spinidorsum Wunderlich 1991. The species D. liostethus Simon 1907 is proposed to be a senior synonym of D. clavisetae Wunderlich 1991 and its presence in the eastern islands is considered to be doubtful. A neotype is designated for D. nesiotes. The distribution of D. alegranzaensis is extended to Lanzarote and the other northern islets. Dysdera nesiotes is reported for the first time in the eastern Canaries. Morphological affinities and distribution patterns are discussed. The remarkably lower number of endemic species harbored by the eastern islands, when compared with other Canarian islands similar in size but younger in age, is proposed to be the result of a major extinction event in the eastern Canaries due to climatic change.

Living on the edge: demographic and phylogeographical patterns in the woodlouse‐hunter spider Dysdera lancerotensis Simon, 1907 on the eastern volcanic ridge of the Canary Islands

“…There are no obvious environmental differences between the collecting localities on the islets and on the main islands, neither are there clear morphological differences, although rigorous morphometric analyses have not been performed. Moreover, high levels of tolerance to a wide range of environmental conditions have been reported in the closely related species Dysdera crocata (Cooke 1968), which seem to be confirmed in D. lancerotensis by its wider distribution range when compared to other Dysdera endemic to the islands (Arnedo et al . 2000).…”

A geographical distribution database of the genus Dysdera in the Canary Islands (Araneae, Dysderidae)

“…Both the youngest (La Palma and El Hierro) and the oldest (Fuerteventura and Lanzarote) islands have less species, but the proportion of island endemics is higher in the oldest islands. This pattern is interpreted as the result of high local diversification and low extinction in the central islands, high extinction rates on the oldest ones due to the habitat lost driven by erosion (Arnedo et al 2000b, Macías-Hernández et al 2008) and the dominant role of immigration on the youngest islands.…”

“…Species richness in Canarian Dysdera is positively correlated with the area, the elevation and the habitat diversity of the islands (Arnedo and Ribera 1999a, Arnedo et al 2000a, Cardoso et al 2010). It shows the typical humpback relationship with age also described for other organisms inhabiting the Canary Islands (Fig.…”

“…The genus is distributed along the circum-Mediterranean region, including the Macaronesian archipelagoes (Deeleman-Reinhold and Deeleman 1988), and presently includes approximately 250 species (World Spider Catalog 2016). To date, 47 endemic species have been documented in the Canary Islands (Arnedo et al 1996, Arnedo and Ribera 1997, Arnedo and Ribera 1999b, Arnedo et al 2000a, Arnedo et al 2007, Macías-Hernández et al 2010). Most of the species are single island endemics, but a few are present in two or three islands.…”

Systematics and phylogeography of the Dysdera erythrina species complex (Araneae, Dysderidae) in Sardinia

“…Morphological methods are described in detail in Arnedo and Ribera (1999) and Arnedo et al (2000). Taxonomic descriptions follow the format of Arnedo and Ribera (1999).…”