Abstract
Recent hyporheic, crenal and phreatic groundwater collections suggest a rich oligochaete fauna associated with the Edwards and Edwards-Trinity Aquifers in central Texas, including many species in the family Lumbriculidae. Based on limited invertebrate collections from earlier sampling programs, four sites were selected for more intensive oligochaete sampling. The lumbriculid Eclipidrilus palustris (Smith, 1900) is widespread in cleaner, cooler waters of the southeastern USA, and was common in crenal habitats. However, several lumbriculid species appear to be new and endemic, four of which are described here. Two of these can be assigned to the genus Eremidrilus Fend & Rodriguez, 2003 based on semiprosoporous male ducts with male pores in X, spermathecae in XI, and a filiform proboscis. Eremidrilus samacos n. sp. has typical morphology for the genus; E. parvitheca n. sp. (provisionally assigned to the genus) has duct-like spermathecae that join the gut, and unusual dorsal glands in posterior segments. Two morphotypes are assigned to E. parvitheca, based on spermathecal location in XI (typical) or XII (variant). A third species (Trichodrilus comalensis n. sp.) lacks a proboscis and has unusually elongated ventral chaetae. A problematic fourth species (Pararhynchelmis texana n. sp.) has semiprosoporous atria in X and duct-like spermathecae joining the gut in VIII. As it lacks apomorphies previously proposed for Rhynchelmis Hoffmeister, 1843 and Pseudorhynchelmis Hrabě, 1982, it is provisionally assigned to Pararhynchelmis Fend & Lenat, 2010.