Pleodamaeus plokosus

Walter, David Evans, 2009, Genera of Gymnodamaeidae (Acari: Oribatida: Plateremaeoidea) of Canada, with notes on some nomenclatorial problems, Zootaxa 2206, pp. 23-44 : 38

Pleodamaeus plokosus ( Woolley & Higgins, 1973a)

( Figs. 27–30 )

Gymnodamaeus plokosus Woolley & Higgins, 1973 a ( Woolley & Higgins 1973b, Subías 2004) Pleodamaeus plokosus (Woolley & Higgins, 1973) ( Paschoal 1983a, Marshall et al. 1987)

Material examined. USA, SOUTH DAKOTA: 2 adults, Jackass Gulch, near Elmore, Lawrence co., RAN86- 114, in PMAE.IZ; female (Gym 61), Ponderosa Pine Duff, Black Hills, SD, 2.vii.73. UTAH: adult (Gym 53) birch duff, Logan Canyon, Utah, 3.v.73; male (Gym 66), maple duff and moss, Blacksmith Fork Canyon, 3.x.70, G.F. Knowlton; female (Gym 46), pine-fir litter, Uintah, G.F. Knowlton; female (Gym 50), birch duff, Box Elder Canyon, 1.vii.73, Utah, G.F. Knowlton; male (Gym 52), birch duff, Cub River Canyon, Idaho, 8.v.69, G.F. Knowlton & Betert. All in OSAL. CANADA, ALBERTA: female, Cypress Hills, Lodgepole Pine Campground, 23.vii.1978, E.E. Lindquist, in PMAE.IZ; adult, Writing-on-Stone Provincial Park, Milk River Valley, 25–30.vii.1978, ex litter in thicket of Pinus and Rosa, E.E. Lindquist , in CNC. SASKATCHEWAN: male (GYM 56), ex natural grassland soil 0–10 cm, Matador IBP, 35 km SE Kyle, 19.vii.1972, in OSAL.

Comments: Pleodamaeus was proposed by Paschoal in Paschoal & Johnston (1982) and further described in Paschoal (1983a) based on a common gymnodamaeid mite found in Colorado, Wyoming, and South Dakota and originally described as a species of Gymnodamaeus ( Woolley & Higgins 1973a). Subsequently, Bayartogtokh (2001) and Bayartogtokh & Smelyansky (2002, 2004) assigned three newly described species to the genus from Mongolia, Kazakhstan, and Russia, respectively. Subías (2004) listed all of these species under Gymnodamaeus .

Although poorly described originally (e.g. P. plokosus has 7, not 6 pairs of genital setae), the Woolley and Higgins species differs from the Asian species assigned to Pleodamaeus . For example, the genital and anal openings are coalesced (vs. separated by an ano-genital bridge), the interlamellar setae are inserted more anterior to the bothridia on converging apophyses (as opposed to between the bothridia) and opposed to a median prodorsal tubercle (apparently absent in Asian species), pedotecta II come to a point (like the ears of the character Spock in Star Trek, Fig. 31 ), and they have a striking autapomorphy: the cluster of integumental tubercles on the anterior median rim of the notogaster ( Fig. 29–30 ). These characters also are present on an undescribed species of Pleodamaeus from Alberta ( Fig. 31 ) in the PMAE.IZ and an apparent third species from the Caribbean in the OSAL. Thus, although the Nearctic specimens conform to the original description, the Asian species described by Bayartogtokh (2001) and Bayartogtokh & Smelyansky (2002, 2004) do not and should probably be assigned to another genus.

Figures

FIGURES 22 – 31. J oshuella agrosticula Paschoal, 1983, Alberta, Canada. 22, Dorsal view (arrow points to longitudinal notogastral ridge), scale bar = 0.05 mm; 23, Ventral view (arrow points to anogenital bridge), scale bar = 0.05 mm; 24, Posterior notogaster showing 4 pairs of setae, scale bar = 10 μm; 25, Notogastral pustules, scale bar = 1 μm; 26, Tritonymph with stacked scalps, scale bar = 0.05 mm. Pleodamaeus plokosus (Woolley & Higgins, 1973), South Dakota, USA. 27, Dorsal habitus, scale bar = 0.1 mm; 28, Notogastral pustule, scale bar = 1 μm; 29, Tubercular patch (arrow) on median anterior rim of notogaster, scale bar = 10 μm; 30, Light micrograph showing tubercular patch and median prodorsal tubercle. Pleodamaeus sp., Alberta, Canada. 31, Anterior notogaster and prodorsum showing acuminate pedotectum II (arrow), scale bar = 0.05 mm.