Oribatella banksi, Behan-Pelletier & Walter, 2012

Behan-Pelletier, Valerie M. & Walter, David E., 2012, 3432, Zootaxa 3432, pp. 1-62 : 11-16

Oribatella banksi sp. nov.

( Figs. 4, 5A–E, 6A–D, 28A, 30A, B)

Material examined. Holotype: adult female. USA: California, Tehama Co., 4mi SW Platina Beegum Creek, 2250’, 3.xii.1986 ( DSC) from Quercus durata , deposited in the CNC, type number 24037 . Paratypes: 7 (4 females, 3 males) with same data as holotype; USA, Oregon, Deschutes Co., Proxy Falls, St. Hwy 242, 28ml SW Sisters, ca. 3000’, 19.viii.1985 ( EEL) 5 females, 2 males from dry moss-lichen mats on rock; USA, Washington, Skamania Co. , Wind River Crane Canopy Research site, 415m , 45°49’14”N 121°57’W, 29.ix.2000 ( VBP) 2 males, 2 females from fir and hemlock forest floor litter; California: Fresno Co., 5.8mi NE Auberry , 14.iii.1985 (P.J. Johnson) 1 female from Neotoma midden; Mendocino Co., Van Damme State Park, Fern Creek Trail , 39°278N 123°757W, 3.iii.2009 ( VBP) 2 females from moss in splash zone of stream; Canada, Bristish Columbia , Vancouver Island , Rocky Point , mixed coniferous and deciduous forest , 48°18.8N 123°36.07W, 30.ix.2005 ( VBP) 1 female from soil and litter under Pacific yew; Alberta: ABMI-33 (59.64667511, -112.275978), along Pine Lake Road, Wood Buffalo National Park , 14.v1.2009, mesic upland pine forest, understory low-bush cranberry, buffalo-berry, blueberry, rose, 5 females, two males; ABMI-OG-1248 (52.53427887, -112.548889), near juncture Route 850 and Range Road 184, 28.v.2011 , mesic upland aspen forest, understory low-bush cranberry, buffalo-berry, blueberry, rose, 6 females; ABMI-A635-1 (55.89463043, -111.675308), SE of Mariana Lake on Highway 63, 13.vi.2011 , mesic upland aspen forest with understory of low-bush cranberry, buffalo-berry, blueberry, rose, 6 females; Moose Pasture Research Site (53.656667, -112.759444), 8 km W Chipman, aspen litter under snow, 17.ii.2008 , 2 females, one male, 8 adults, 19 May 2008 ( DEW) . Paratypes deposited in the CNC, PMAE . IZ, RNC and USNM .

Diagnosis. Length of adult 400–445 µm. Rostrum strongly ornamented with foveae, ridges and pits; medially undulating, to medially acuminate with pair of small lateral teeth. Lamellar cusp strongly convex medially, pair overlapping anteromedially but separated posteromedially, leaving prodorsum visible through semi-triangular oval opening (14–17 µm wide x 24 µm long); translamella without medial tooth. Medial dens on lamellar cusp 43–53 µm long, without marginal teeth, subequal or longer than lateral dens (39–43 µm long) with 2–3 marginal teeth. Bothridial seta about 111 µm long, with barbed, fusiform head, tapered to flattened distally, stalk short, smooth. Octotaxic system expressed as 4 pairs of porose areas with deep pore canals (easily confused with saccules). Ten pairs of long (60–78 µm), finely barbed notogastral setae present, with c seta longest; lm posterior of Aa, lp anterior of A1; distance h 1 –h 1 30–45 µm, wider than distance p 1 –p 1, 20–28 µm. Seta 4c largest epimeral seta (64–70 µm), barbed, thickened, longer than both custodium (about 37 µm) and narrow, barbed seta 3c (52–60 µm). Anterior border of mentum with thickened, reverted transverse ridge, without tectum. Tarsi heterotridactylous.

Description. Adult. Dimensions: Mean total length female (n = 9) 431 µm (range 415–445), mean total length male (n = 5) 414 µm (range 400–440). Mean notogastral width female (n = 7) 288 (range 280–300); mean notogastral width male (n = 5) 285 µm (range 270–300) µm.

Integument: Prodorsum, notogaster, anal plates, genital plates, and venter micropunctate. Mentum foveolate. Coxisternum with distinct striae. Pedotectum I with network of ridges and foveae. Pteromorph with striae distally. Lamella with weakly reticulate pattern laterally, densely punctate distally. Rostrum strongly ornamented with foveae, ridges and pits ( Fig. 5D, 6A).

Prodorsum: Rostral margin undulating medially, to medially acuminate with pair of small lateral teeth, with ridge running at angle from apex of rostral crest to insertion of seta ro, or ridge running parallel to rostral crest; rostral margin appearing trifurcate in dorsal aspect ( Fig. 5D). Lamella 129–150 µm long, of which cusp about 84–100 µm long, 52–60 µm wide at level of insertion of seta le. Lamellar cusps strongly convex medially, overlapping anteromedially, separated posteromedially, leaving prodorsum visible through semi-triangular oval opening (14–17 µm wide x 24 µm long); translamella without medial tooth, 15–17 µm at greatest width, 12–14 µm at greatest depth ( Figs 4, 5A, 6B). Medial dens on lamellar cusp 43–53 µm long, without marginal teeth, subequal or longer than lateral dens (39–43 µm long) with about 2 marginal teeth ( Figs 4, 6B). Seta ro 87–100 µm long, strongly barbed along length, acuminate, curved anteromedially. Seta le about 92 µm long, thick, heavily barbed, tapered. Seta in about 150 µm long, thick (less so than le), heavily barbed, tapered; mutual distance of insertions of pair about 58 µm. Bothridial seta about 111 µm long, with barbed, fusiform head, tapered to flattened distally, stalk short, smooth; head directed slightly anterodorsally ( Figs 4, 5A, 6B). Exobothridial seta barbed, about 16 µm long.

Lateral region of podosoma: Genal tooth broad, subrectangular, with dens ventrodistally, with longitudinal ridge ventrolaterally ( Fig. 5E, 6C). Tutorium about 142–146 µm long, of which cusp about 65–70 µm long, rectangular, distal margin with 4–6 teeth ( Fig. 5E, 6C). Custodium about 37 µm long, tapered ( Fig. 5C, 28A). Porose area Al about 10 µm in diameter.

Notogaster: Length subequal to width. Anterior margin undulating, convex region lateral of bothridium with 7–10 transverse ridges. Pteromorph with striae forming weak reticulate pattern; with minute teeth along anterior margin and small dens on anteroventral margin ( Fig. 5C). Octotaxic system in form of small, porose areas, about 8 µm in diameter, with deep pore canals (easily confused with saccules) ( Figs 30A, B). Ten pairs of finely barbed acuminate notogastral setae present (60 to 78 µm long) c seta longest, setae lm posterior of Aa, lp anterior of A1; distance h 1 –h 1 30–45 µm, wider than distance p 1 –p 1, 20–28 µm ( Fig. 4). Broadly subtriangular lenticulus present.

Ventral Region: Seta 4c largest epimeral seta, barbed, thickened, 64–70 µm ( Figs 5C, 6D, 28A), 3c barbed, subequal in shape to other epimeral setae, 52–60 µm long; other epimeral setae mostly 20–26 µm long, weakly barbed. Genital, aggenital, anal and adanal setae weakly barbed, about 8–15 µm long. Genital setae 2+4. Lyrifissure iad on level with anterolateral corner of anal plates. Postanal porose area oval, about 20 x 5 µm.

Gnathosoma : Anterior border of mentum with small reflected ridge, without tectum ( Fig. 5B). Axillary saccule about 5 x 2 µm.

Legs: Setation (I to IV): trochanters, 1-1-2-1; femora, 5-5-3-2; genua, 3(1)-3(1)-1(1)-2; tibiae 4(2)-4(1)-3(1)- 3(1); tarsi, 20(2)-15(2)-15-12. Seta l” on genua I and II about 43 and 52 µm, respectively; l” on tibiae I and II each about 35 µm. Tarsi heterotridactylous.

Etymology. This species is named in honour of Nathan Banks, who worked extensively on North American Acari, including Oribatida, from 1895 to 1947. He is author of the genus Oribatella .

Remarks. This species is very similar to Oribatella maryae sp. nov., described below; they share similar lamellae, lamellar cusps, notogastral porose areas with deep pore canals (when viewed in transmitted light), custodium and setae 3c and 4c. They differ in the following character states (those for O. maryae in parentheses): body length 400–440 µm (360–390 µm), rostrum strongly ornamented with foveae, ridges and pits (weakly micropunctate); rostral margin undulating to pointed medially with or without minute lateral teeth (with medial tooth and 2 strong lateral teeth); distance h 1 –h 1 30–45 µm (24 µm).

Distribution and Ecology. Oribatella banksi is known primarily from deciduous and coniferous forest litter and dry litter habitats from British Columbia and Alberta, south to central California. Gravid specimens from Alberta carry two eggs; gut contents are composed primarily of dark fungal spores and hyphae.