The genus Metaporcelaimus Lordello, 1965 (Nematoda, Dorylaimida, Aporcelaimidae) in Ukraine: Description of one known and two new species without hiatus.

One known (M. romanicus) and two new species of the genus Metaporcelaimus, collected in natural and semi-natural habitats of Ukraine, are described and illustrated. Metaporcelaimus concinnus sp. n. is characterized by its 3.09-4.58 mm long body, lip region 16.5-19.5 µm broad and visibly wider than the adjacent body, odontostyle 17-19 µm long, neck 745-865 µm long, pharyngeal expansion occupying 62-66% of total neck length, uterus tripartite and 3.9-5.7 times the corresponding body diameter, vulva longitudinal (V = 49-53%), tail conical (44-54 µm, c = 67-94, c' = 1.0-1.3 in females), spicules 79-86 µm long with strongly bifurcate distal end, and 10-14 irregularly spaced ventromedian supplements without hiatus. Metaporcelaimus declivicaudatus sp. n. is characterized by its 2.88-3.66 mm long body, lip region 23-28 µm broad, odontostyle 24-26 µm long, neck 634-788 µm long, pharyngeal expansion occupying 48-56% of total neck length, uterus tripartite and 3.0-3.4 times the corresponding body diameter long, vulva transverse (V = 51-55%), tail conical (45-65 µm, c = 53-63, c' = 1.0-1.2) with rounded terminus, spicules 102-113 µm long, and 12-14 spaced ventromedian supplements without hiatus. New information about M. romanicus is also provided, confirming available data about this species.