Stauratostoma shelleyi n. gen., n. sp. (Nematoda: Rhabditida: Thelastomatidae) from Appalachian Polydesmid Millipedes (Polydesmida: Xystodesmidae)

Stauratostoma shelleyi n. gen., n. sp. is described from the midgut and hindgut of nine species of the millipede family Xystodesmidae collected in the southern Appalachian regions of North Carolina, Tennessee and Alabama. Specimens of S. shelleyi were morphologically examined with differential interference contrast, phase contrast, and scanning electron microscopy. The head of S. shelleyi differs from other thelastomatid nematodes in having a head region mushroom-shaped in profile; cruciform stomatal opening formed from four flaps; greatly expanded labial disc; and eight-sectored annule-like column supporting the labial disc. Thirteen nematodes from various hosts were sequenced for 28S LSU rDNA and compared with other millipede-inhabiting nematodes. Stauratostoma shelleyi is the sister group to the few Thelastoma spp. that have been molecularly characterized using the D2–D3 expansion segments of the 28S LSU rDNA.