Morphological and molecular characterization of Xiphinemella esseri Chitwood,1957 (Dorylaimida: Leptonchidae) from Florida, with the first molecular study of the genus

Abstract

A population of Xiphinemella esseri, recently collected under the canopy of associated live oak trees in north Florida, was studied and described with an integrative approach, including the first molecular study of the genus. This Florida population is characterized by its 2.30 to 3.32 mm long body, labial disc well developed, lip region offset by constriction, and 16.5 to 17.5 mu m broad, odontostyle 46 to 49 mu m long with minute aperture, neck 288 to 296 mu m long, pharyngeal expansion occupying 28 to 30% of total neck length, uterus a tripartite tube-like structure, pars refringens vaginae absent, vulva transverse (V = 45.4-49.7%), tail short and rounded (18-28 mu m, c = 94-158, c' = 0.6-0.9), spicules 41 to 45 mu m long, and 8 to 10 irregularly spaced ventromedian supplements bearing hiatus. The phylogenetic analysis inferred from the D2-D3 expansion segments of 28S rRNA gene and 18S rRNA gene sequences showed that X. esseri clustered with other dorylaims from the family Leptonchidae. A brief discussion about the distribution and biological considerations of X. esseri is also provided.