Oligoclada mortis sp nov from Rondonia State, Brazil, and distributional records of other species of the genus (Odonata: Libellulidae)

Oligoclada mortis sp. nov. (holotype male deposited in MZSP: Brazil, Rondonia State, Porto Velho municipality, "T[ransect] 5-21, seg[ment]12" (09 degrees 35'19 '' S, 65 degrees 02'50 '' W, 106m asl, 13 v 2010, leg. Nogueira & Mendes) is described and illustrated based on two males. The new species fits within Borror's Group III, differing from all other described species in the genus by the combination of an entirely black labium, a large posterior hamule, sickle-shaped and ventrally longer than the genital lobe, and long cerci, with the ratio between epiproct and cerci less than 0.67. A key to males of the seven species of Group III and distributional records based on the specimens deposited in the DZRJ and MZSP Brazilian collections are also presented. The new species is the eighth species of Oligoclada reported from Rondonia, this being the richest Brazilian State for this genus.