Abstract
Two new and an undetermined/unnamed species in the penicillate diplopod genera Lophoturus
BROLEMANN, 1931 and Macroxenodes SILVESTRI, 1948 are described from the vicinity of Manaus,
Central Amazonia, Brazil: L. adisi n.sp., M. amazonicus n.sp., and M. sp.. L. adisi n.sp. is characteristic
in having the molar plate with a swollen dorsal molar plate shoulder of the mandible, while M. amazonicus
n.sp. in having three thick bacilliform dorsal sensilla separated from a second group of posterior ventral
sensilla on antennal segment VI, the gnathochilarium wìth 21 to 23 palpal sensilla and the femoral and
tibial setae with a noval base furnished with 3 or 4 long spines. Also, L.adisi n.sp., which is the dominant
species at the locality, has been investigated as to its postembryonic stadia and rnandibular structure. On
the other hand, M. sp. is characteristic in having more numerous sensilla located in one or two rows in the
dorso-distal part of antennal segment VI, in the tergal trichomes grouped in two separated oval areas, and
in 22 or 23 palpal sensilla. Plesioproctus CONDÉ, 1964 is shown to be a junior synonym of Ancistroxenus
SCHUBART, 1947, n. syn. The synonymy results from a revision of type material of the Brazilian
Ancistroxenus tupiensis SCHUBART, 1947. Plesioproctus comans (LOOMIS 1934), from Trinidad, is
formally transferred to Ancistroxenus, resulting in A. comans (LOOMIS 1934), n. comb., a species which
is also a subjective senior synonym of Ancistroxenus tupiensis SCHUBART, 1947, n. syn.. A. comans has
been recorded from the study region for the first time, and its postembryonic stadia are fully redescribed.
A key to the genera of the family Lophoproctidae is given.
