A new yellow sac spider: Cheiracanthium ilicis

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Cheiracanthium is a genus of spiders also commonly known as yellow sac spiders. As it happens some Cheiracanthium species are attracted to the smell of petroleum. The animals caused problems by weaving webs inside the canister vent of particular models of Mazda vehicles, resulting in blockages and build-up of pressure that could potentially cause fuel leakage. Mazda therefore issued a recall of Mazda 6 models to fit them with software which would alert drivers if problems were developing.

Our new species was found in the Toledo region in Spain.Most of the individuals of this novel species were collected from Holm oaks. The Latin name of this oak species (Quercus ilex) has been thus used to name this spider so as to link it to the main habitat it occupies.

For the experts: We describe a novel species Cheiracanthium ilicis sp. n. (Araneae, Eutichuridae) collected in the province of Toledo (Central Spain). It was found during a systematic sampling campaign carried out in an agricultural landscape with isolated Holm oaks Quercus ilex and small forest patches. Its morphology and affinities with other species of the genus are discussed. Furthermore, one mitochondrial gene was sequenced to confirm species membership and its differentiation from other Cheiracanthium species. The molecular phylogenies based on mitochondrial and nuclear genes showed a close relationship of C. ilicis sp. n. with C. inclusum and C. mildei, with which it also shares morphological similarities. Nonetheless, the sparse sampling of the phylogeny, due to the low number of sequences available, impedes drawing any definitive conclusion about these relationships; it is first necessary to perform an extensive review of the genus worldwide and more thorough phylogenies. C. ilicis sp. n. also shares certain ecological and phenological characteristics with C. inclusum and C. mildei. Like them, C. ilicis sp. n. is an obligate tree dweller that prefers a tree canopy habitat and reproduces primarily in late spring and summer. From a conservation perspective, the present study suggests the need to preserve isolated trees in agricultural landscapes. They are not only the refuge of common forest organisms but also of novel species yet to be discovered.