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 & Lisetskaya, originally described from Moldova and subsequently also detected at sites in the Middle East and near the Mediterranean. Herein, Acromoldavicus mojavicus n. sp. is described from sandy soil surrounding a Joshua tree (Yucca brevifolia) in a remote area of the Mojave Desert, California, USA. The lip region of A. mojavicus n. sp. is bilaterally symmetrical with three triangular probolae surrounded by three pairs of plate-like lips. The lip region is organised along similar lines as that of A. skjabini, but differs in several respects, such as its larger size, presence of elongate posterior processes on each lip and division of the lateral lips into two lobes (excluding the dorso-sublateral guard processes). In addition, phylogenetic interpretation of sequence data from the large-subunit of ribosomal DNA provides 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 papillae. Both species of Acromoldavicus have a buccal capsule with a reduced gymnostom, a character that seems to be shared with the cephalobid Elaphonema and in part is a basis for placement of both genera in Elaphonematidae. The species A. mojavicus n. sp. exhibits additional similarities with Elaphonema spp. that further support this placement.