Acromoldavicus mojavicus n. sp (Nematoda : Cephaloboidea) from the Mojave Desert, California

Acromoldavicus (Cephalobina, Cephaloboidea) with its highly distinctive lip region has only a single species, Acromoldavicus skrjabini Nesterov & Lise tskaya, originally described from Moldova and subsequently also detected at sites in the Middle East and near the Mediterranean. Herein, Acromoldavicu s mojavicus n. sp. is described from sandy soil surrounding a Joshua tree ( Yucca brevifolia) in a remote area of the Mojave Desert, California, USA. T he lip region of A. mojavicus n. sp. is bilaterally symmetrical with three triangular probolae surrounded by three pairs of plate-like lips. The lip r egion is organised along similar lines as that of A. skjabini, but differs in several respects, such as its larger size, presence of elongate posterio r processes on each lip and division of the lateral lips into two lobes (ex cluding the dorso-sublateral guard processes). In addition, phylogenetic in terpretation of sequence data from the large-subunit of ribosomal DNA provi des further evidence for autapomorphies and separate species status for A. skrjabini and A. mojavicus n. sp. Characteristics shared with Cephaloboidea include the offset spermatheca and males with eight pairs of genital papil lae. Both species of Acromoldavicus have a buccal capsule with a reduced gy mnostom, a character that seems to be shared with the cephalobid Elaphonema and in part is a basis for placement of both genera in Elaphonematidae. Th e species A. mojavicus n. sp. exhibits additional similarities with Elaphon ema spp. that further support this placement.