Complementary description of Africoseius lativentris and placement of Africoseius in Podocinidae (Acari, Mesostigmata) based on molecular and morphological evidences

Morphological details of specimens collected from several localities in Brazil and identified as Africoseius lativentris (Karg 1982) are provided. The taxonomic position of Africoseius Krantz, 1962 has been debated over the years, with repeated changes in its familial placement. A phylogenetic study based on 18S and 28S rDNA sequences of the Brazilian population of A. lativentris collected at Jaboticabal, Sao Paulo State, and similar data of 70 taxa representing 11 families of Gamasina indicated that Africoseius is a member of the well-supported Podocinidae (sensu Lindquist et al. 2009) Glade. The main morphological similarities and differences between Africoseius and the group of species until now placed in Podocinidae sensu Lindquist et al. (2009) are listed. Apomorphic characteristics uniting those taxa include the hypotrichous condition of tibia I (eight and nine setae instead of ten or more in other free-living Gamasina) and the insertions of av2 and pv2, considerably more distal on tarsi II and III than in the majority of the free-living Gamasina. Within Podocinidae, a new subfamily, Africoseiinae, is proposed, based on uniquely apomorphic characteristics of the setae ad4 and pd4 (sensu Evans 1969) of tarsi II-IV absent, and setae av4 and pv4 of same basitarsi long, incurved and close to each other and to a posterior longitudinal extension of the peripodomeric suture and on the attenuated form of the lateral (rather than the medial) hypostomatic setae. This subfamily is currently represented by Africoseius areolatus Krantz and Africoseius lativentris (Karg 1982), while all other presently known species of the family are now placed in the subfamily Podocininae. (AU)