Steinernema unicornum Egington, buddie Tymo, France, Merino & Hunt, 2009
Summary:
A new species of entomopathogenic nematode, Steinernema unicornum
was isolated from a soil sample taken from the archipelago of Tierra del Fuego,
southern Chile.
The new species is characterised by a prominent, dorsally located, horn-like
tooth on the cephalic extremity of the infective juvenile (a feature unique for
the family); lateral field pattern of 2, 6, 8, 4 ridges; and morphometrics of
the infective juvenile with body length of 732 (654-786) μm, excretory pore
located 55 (48-62) μm posterior to the cephalic extremity, tail 60 (50-71) μm
long, H% = 37 (24-49), E% = 91 (77-116) and a ratio = 25.4 (21.9-29.4).
The first generation male has spicules 73 (60-82) μm long, gubernaculum 48
(44-52) μm long and SW% = 198 (184-217). The first generation female can be
recognised by the presence of a series of transverse cuticular folds and ridges
located immediately anterior and posterior to the vulva, the lack of a
prominent post-anal swelling, and presence of a mucron-like projection on the
tail tip. Sequences of the ITS and D2D3 regions of the ribosomal DNA confirm
that S. unicornum is a valid species.