A new species of Modisimus Simon (Araneae: Pholcidae) in Baja California Sur, Mexico.

The genus Modisimus Simon 1893 (Pholcidae) is distributed across the Americas from Venezuela to the USA, including the Caribbean Antilles, with an endemic species in the Galapagos Islands and one cosmopolitan species (World Spider Catalog 2015). Until now, 81 species of Modisimus have been described, of which 17 species are found in Mexico (World Spider Catalog 2015). In this paper, a new Mexican species is described. Modisimus species are mainly found in humid tropical forests in shady, humid places near the ground, with their webs extended between buttresses of trees, fallen logs, or rocks (Huber 1998), and only one species (M. vittatus Bryant, 1948) is found in city gardens, exposed road embankments, as well as among cacti and agaves in semi-arid scrubland (Huber et al. 2010). This genus is also common in caves where pholcids population can be abundant (Gertsch 1971, 1973, 1977; Valdez-Mondragón & Francke 2009). The specimens were manually collected in the State of Baja California Sur in a coastal oasis adjacent to the Pacific coast. Male and female genitalia were dissected; female genitalia were cleaned with 10% lactic acid for one min. Drawings of both genitalia were made with a camera lucida adapted to a stereomicroscope (MZ6, Leica Microsystems, Weztlar, Germany). Photographs were taken with a camera adapted to the mentioned stereomicroscope and LAS 4.1.0 software for editing pictures. The micrographs were made on a scanning electron microscope (SEM; S-3000N, Hitachi, Tokyo, Japan). The terminology is based on Huber (1998, 2010). The measurements are in millimeters. Abbreviations in the text and figures are: AME (anterior median eyes), ALE (anterior lateral eyes), PME (posterior median eyes), PC (procursus), BA (bulbal apophysis), CA (coxal apophysis), FA (femoral apophysis), PP (pore plates). The specimens are conserved in 80% ethanol and deposited in the Colección Aracnológica del Centro de Investigaciones Biológicas del Noroeste, La Paz, Baja California Sur, Mexico (CARCIB, Maria-Luisa Jiménez).