First record of a sea spider (Pycnogonida) from an anchialine habitat

The anchialine fauna from the Yucatan Peninsula has been extensively studied since the 1980 ' s. "Sea spiders" or Pycnogonida, have never been found in these systems before. A record for Anoplodactylus batangensis (Helfer, 1938) from a cenote (sinkhole) in the Yucatan Peninsula, Mexico is presented herein. The pycnogonid was found in waters of the cenote Nohoch Nah Chich, part of the Sac Actun anchialine system, in the State of Quintana Roo. This species was already reported from the northeastern shore of the Yucatan Peninsula, however the record we present herein constitutes the first time a pycnogonid is reported from an anchialine habitat. A brief description of the female A. batangensis is presented for the first time.