Onchogamasus Womersley

Castilho, Raphael C., Silva, Edmilson S., De, Gilberto J. & Halliday, Bruce, 2016, Catalogue of the family Ologamasidae Ryke (Acari: Mesostigmata), Zootaxa 4197 (1), pp. 1-147 : 19

Onchogamasus Womersley (4 described species)

Movable and fixed cheliceral digits with 2–5 and 3–7 teeth, respectively. Epistome with an anteromedian extension wider at base and acute distally, smooth or serrated. Seta h 3 about in longitudinal line with h 1 and in transverse line and mediad to h 2. Idiosoma elongated or suboval, 310–560 µm long and 180–340 µm wide at widest level. Podonotal and opisthonotal shields fused, forming holonotal shield (an incomplete apparent line of fusion is present in O. communis , sloping backward from setae J 1). Dorsal idiosomal setae aciculate and smooth. Podonotal region of dorsum with 20–23 pairs of setae, of which 20–23 pairs on podonotal shield and with 0–1 pair on soft integument along lateral margins of podonotal shield. Opisthonotal region with 15–22 pairs of setae, of which 15–22 pairs on opisthonotal shield and 0–1 pair on soft integument along lateral margins of opisthonotal shield. Seta j 1 not on prominent protuberance, shorter than r 3 and Z 5. Holonotal and ventrianal shields separated. With 1–3 pairs of presternal platelets (fused to sternal shield in O. quasicurtipilus ). Sternal shield fused to endopodal shield near coxa IV; seta st 3 mediad to imaginary line between st 1, st 2 and st 4. Opisthogaster without platelets between genital and ventrianal shields; with 5–8 pairs of setae on ventrianal shield and 0–2 pairs on soft integument around ventrianal shield; post-anal seta longer than or as long as para-anal seta. Peritreme with straight or smoothly curved margins, extending anteriorly to level between posterior margin of coxa II and coxa I. Peritrematal shield not fused posteriorly to exopodal shield near coxa IV (fused in O. communis ). Exopodal shields near coxae II–III–III divided at median level of coxa III (fused in O. communis ). Without distinct metapodal platelets. All legs with pretarsi. Genua I, III and IV and tibia IV with 13, 9, 10 and 10 setae, respectively.