Cervidellus sonorensis n. sp. is described from sand near the roots of creosote bush (Larrea tridentata) from Anza-Borrego Desert State Park, CA, USA. It is distinguished from others in the genus by the combination of a greatly distended, guitar-shaped corpus and the morphology of the lips and labial probolae. Distinctive features include a large pharyngeal metacorpus with a double swelling, a knob-like ledge at the base of each labial probola and lips with five filamentous tines, the most apical of which are those closest to the primary axil. One male individual was discovered in this parthenogenetic species. Characters used to diagnose C. sonorensis n. sp. are not definitive with respect to other genera and are probably plesiomorphic or convergent in light of DNA-based phylogenetic hypotheses. The position of C. sonorensis n. sp. and morphologically close congeners in relation to species of Nothacrobeles and Paracrobeles is discussed.