Donjohnstonella subalpina (Paschoal, 1982)

Walter, David Evans, 2009, Genera of Gymnodamaeidae (Acari: Oribatida: Plateremaeoidea) of Canada, with notes on some nomenclatorial problems, Zootaxa 2206, pp. 23-44 : 31-32

Donjohnstonella subalpina (Paschoal, 1982)

(Figs. 15–16)

Material examined: USA, WASHINGTON: Holotype (see Comments) female ex subalpine fir litter, Mt Rainier, WA, 6.vii.1973, NGN1, 0 0 7806, OSAL 0 0 81533.

Comments: In Paschoal & Johnston (1982), Paschoal named “ Johnstonella subalpina Paschoal n. gen., s. [sic] sp.” (p. 450), along with diagnostic characters; thus establishing this genus and species. The name Johnstonella , however, is pre-occupied by the tomopterid polychaete genus Johnstonella Gosse, 1853 (often now treated as a subgenus of Tomopteris Eschscholtz ). In order to retain the meaning of the original author, i.e. to name the genus in honor of Donald E. Johnston, I propose the replacement name Donjohnstonella. As noted above, since the tritonymph of Gymnodamaeus meyeri Bayartogtokh & Schatz expresses both seta h 3 and lp, the identity of the extra notogastral seta in D. subalpina is unclear, but I am using h 3.

Paschoal (1983d) reported the holotype to be a male, but the labelled holotype specimen from OSAL examined is a dorsally mounted female with a distinct ovipositor. Presumably this is typographical error, since the only paratype female reported is in the author’s collection in Brazil. This specimen appears to be infected with a parasitic microorganism, oval to circular (5–9 long) with hyaline halo (~1 thick) and darker, granulate core. Three gut boli composed of dark fungal mycelium are present. Donjohnstonella subalpina is known from three mites collected from subalpine fir litter on Mt Rainier in Washington, USA ( Paschoal 1983d) and is not yet known to occur in Canada. Subías (2004) considers D. subalpina to be a species of Gymnodamaeus , but it can be separated from that genus by the presence of seta h 3 on the notogaster (as in some Plateremaeidae ), 3 setae on femur IV (2 in Gymnodamaeus s.s.), the lack of a ridge connecting the apophysis bearing the interlamellar seta to the bothridium, the tooth on the posterior rim of the bothridium (Fig. 15), the bullet-shaped cerotegument (Fig. 16 vs Fig. 3 ), and the lack of a nipple-like tubercle between setae h 1.

Figures

FIGURES 1 – 8. Gymnodamaeus cf. ornatus Hammer, Alberta, Canada; scale bars = 0.1 mm, except Fig. 3 = 1 μm. 1, Prodorsum showing interlamellar seta (in) on apophysis at median edge of bothridial ridge and opposed to median prodorsal tubercle (larger arrow); 2, Prodorsum and anterior notogaster; 3, Spherical crystalline notogastral pustules; 4, Ano-genital region, arrow points to soft cuticle between genital and anal openings; 5, Dorsal habitus view showing Ushaped raised notogastral ridge pattern; 6, Rostrum from anterior view; 7, Light micrograph of ano-genital region, arrow points to preanal organ; 8, Genu IV (DIC micrograph) showing normal joint, i. e. lacking retrotecta, between femur (top) and tibia.