S. Mahunka szerk.: Folia Entomologica Hungarica 48. (Budapest, 1987)

Type material: Holotype: (1252-HO-87): Afr. 203: Nigeria, Bauchi State, Yankari game reserve, humus and litter from gallery forest of Wikki stream. 10. VU. 1978. leg. A. DEMETER; 1 paratype: Afr. 201: Nigeria, Bauchi State, Yankari game reserve Wikki village, soil sample from grassland, 10. Vn. 1978. leg. A. DEMETER; 34 paratypes: Afr

.202: Nigeria, Bauchi State, Yankari game reserve, Wikki village, litter of leares and twigs + watervuck (Kobus defassa) droppings in sparse grassland, 10. VII. 1978. leg. A. DEMETER; 15 paratypes: Afr. 206: Nigeria, Bauchi State, Yankari game reserve, Wikki, decaying bark of trees, 10. VII. 1978. leg. A. DEMETER; 2 paratypes: Afr. 207: Nigeria, Bauchi State, Yankari game reserve, Wikki, old elephant (Loxodonta africana) dung. 10. VII. 1978. leg. A. DEMETER; 1 paratype: Afr. 211: Nigeria, Bauchi State, Yankari game reserve, Wikki, bark of tree, 22. VII. 1978. leg. A. DEMETER; 4 paratypes:,. Afr. 218: Nigeria, Bauchi State, Yankari game reserve, 1 km W of Wikki, litter + skin of fruit, 3

J

. VHI. 1978. leg. A. DEMETER; 2 paratypes: Afr. 221: Nigeria, Bauchi State, Yankari game reserve, Gaji river, humus + litter from swamp forest, 3. Vni. 1978. leg. A. DEMETER; 3 paratypes: Afr. 223: Nigeria, Bauchi State, Yankari game reserve, 1 km W of Wikki, humus + litter, 3. Vni. 1978. leg. A. DEMETER. Holotype and 62 paratypes (1252-PO-87) deposited in the HNHM, 4 paratypes in the MHNG. Remarks: The new species comes nearest to Passalozetes wolnekranensis Engelbrecht, 1974 from South Africa. The new species is distinguished from the latter by the much shorter cilia of the sensillus, the branching ribs of the prodorsum, the ornamented genital plates and by the sculpture of the ventral plate (the lack of thickened, short, branching ribs on the ventral plate laterally in the South African species). Oribatula incompleta sp. n. Measurements. - Length: 322-338 um, width: 204-216 urn. Prodorsum: Rostrum with nasiform, strongly pointed apex. Rostral and lamellar setae setiform, thin, interlamellar ones thicker and more pilose than the preceding setae. Ratio of prodorsal setae: le>ro>in>ex. Interlamellar setae arising comparatively far from the dorsosejugal suture. Lamellae converging anteriorly, with very long and we 11-separated apex. Translamella weaky developed, interrupted medially (Fig. 34). Sensillus short, its clavate head not longer than the peduncle. A thin tutorium present (Fig. 35). Notogaster: Dorsosejugal suture strongly convex medially. A well-developed shoulder observable Fourteen pairs of short but strong notogastral setae present. Setae C3 and la originating very near to areae porosae Aa (Fig. 32). Lyriflssures im open far from the lateral margin of notogaster. Areae porosae Aa and Aj nearly equal in size, A

2 and A

3 much smaller. No sculpture on notogaster. Coxisternal region: Pedotecta I large, ornamented by some rugae (Fig. 33). Epimeral surface - with the exception of posteromedian part - smooth, preceding surface with some foveolae. Apodemes and borders - excepting sejugal ones - hardly observable, or reduced. All epimeral setae (epimeral setal formula: 3-1-3-3) short, setae lc, 3c and 4c stronger than the others, these 3 pairs well pilose (Fig. 35 ). Anogenital region: Ventral plate foveolate medially, smooth laterally and posteriorly. Anogenital setal formula: 4-1-2-3. All setae In this region short. Lyriflssures iad open in front of the anal aperture

. Legs: All legs tridactylous, median claw much stronger than the lateral ones. Type material: Holotype (1253-HO-87): Afr. 206: Nigeria, Bauchi State, Yankari game reserve, Wikki, decaying bark of trees, 10. VII. 1978. leg. A. DEMETER; 1 paratype: from the same sample; 1 paratype: Afr. 222: Nigeria, Bauchi State, Yankari gare reserve, 1 km W of Wikki, old buffalo (Synceros caffer

) dung. 3. VIII. 1978. leg. A. DEMETER; 1 paratype: Afr. 223: Nigeria, Bauchi State, Yankari game reserve, 1 km W of Wikki, humus + litter, 3. Vni. 1978. leg. A. DEMETER. Holotype and 3 paratypes (1253-PO-87) deposited in the HNHM, 1 paratype in the MHNG. Remarks: The new species belongs to the "

interrupta" species group (

Zygoribatula interrupta Willmann, 1939, Z. pallida Banks, 1906, sensu Hammer, 1952, (?) Oribatula divtda Mahunka, 1987, O. acuminata Wallwork, 1964), which is characterized by the incomplete trahslamella, the short notogastral setae and by the comparatively long and well-definied lamellar cuspis. The new species is distinguished from all similar relatives by the plumose and thick interlamellar setae, the sculpture of the ventral plate, and by the sharply pointed apex of the rostrum. It stand nearest to O. acuminata Wallwork, 1964, however, it is distinguished from the latter by the sculptured ventral plate and the presence of the well-developed lamellar cuspis.