Two new species of penicillate millipedes (Diplopoda, Polyxenidae) from Phu Quoc Island in southern Vietnam

Two new penicillate millipede species from the genera Unixenus and Monographis (Diplopoda, Polyxenidae) were collected
from Phu Quoc Island, Vietnam’s largest island. Unixenus intragramineus sp. n. was found within the stem of a
creeping grass growing on an unstable, sandy substrate in the intertidal zone. The defining taxonomic characteristics of
the genus Unixenus were apparent in U. intragramineus sp. n., but it is distinctively different from all described species.
Monographis phuquocensis sp. n. belongs to a group of Monographis species which have their antennal sensilla arranged
in a crescent-shape; but the structure of the labrum and telotarsus observed in this new species differs from other described
Monographis.