Chinchippus

Abstract: Two species of Chinchippus (Ammotrechidae) were studied in central Peru. Both species are endemic to the hyper-arid coastal desert and appear to derive most of their energy and nutrients from maritime prey, such as intertidal amphipods feeding on beach-cast algae or as arthropod scavengers feeding upon seabird and pinniped carcasses. Data on the spatial distribution of the two species were obtained from analyzing stomach contents of one common predator, the gecko Phyllodactylus angustidigitus, and suggest that both species are more abundant in insular than in mainland habitats. We redescribe Chinchippus peruvianus Chamberlin 1920, known only from a female specimen and describe the male for the first time while C. viejaensis is recognized as new. The new species is distinguished from C. peruvianus by its darker coloration, smaller size, and differences in cheliceral dentition. In the process of investigating the ecology of terrestrial organisms in the coastal desert and guano islands of central Peru, we have come across a series of Chinchippus peruvianus Chamberlin 1920 and a closely related species. These solifuges, along with other terrestrial predators, thrive in places that could be defined as a barren land of gravel, sand, and granitic outcrops - a moonscape where arachnids and lizards somehow manage to survive, reproduce, and colonize new habitats. The western coast of South America is among the driest places on Earth (Dietrich & Perron 2006), where arid conditions have persisted for the last 14 million years (Alpers & Brimhall 1988). Facing this hyper-arid ecosystem is one of the world's most productive marine ecosystems, the Peru-Chile cold current (Tarazona & Arntz 2001). The stark contrast in productivity promotes the exchange of energy and nutrients between these two adjacent ecosystems, and marine-derived resources subsidize terrestrial predators along the Peruvian coast (Catenazzi & Donnelly 2007a) and in other coastal deserts (Polis & Hurd 1996). In this study we describe the taxonomy and natural history of the two Chinchippus species and explore their distribution in relation to the availability of marine-derived resources. The genus Chinchippus was established by Chamberlin (1920) based on a single female from the Peruvian island of Chincha. He considered it to belong to the African family Daesiidae. Roewer (1934) included Chinchippus in the ammotrechid subfamily Saronominae based on the segmenta- tion of legs I, II, and IV and the palpal spination. Muma (1976) tentatively included it with the saronomines although its placement was still based on Chamberlin's sole female. Based on Chamberlin's single female, the genus Chinchippus can be recognized by: all the legs having a single tarsal segment, no claws on leg I, stridulating ridges on the mesal surface of the chelicera, lateral plates of the ''rostrum'' shorter than the median plates, and a recurved cephalothorax.