Oribatella sintranslamella, Behan-Pelletier & Walter, 2012

Behan-Pelletier, Valerie M. & Walter, David E., 2012, 3432, Zootaxa 3432, pp. 1-62 : 45-48

Oribatella sintranslamella sp. nov.

( Figs. 23, 24, 30F)

Material examined. Holotype: adult female, USA, Oregon, Deschutes Co., Proxy Falls, St. Hwy 242, 28 mi SW Sisters, ca. 3000’, 20.xiii.1985 ( EEL) from deep, damp, mixed maple-hemlock litter, rotten wood; deposited in the CNC, type number 24045 . Paratypes: 10 males, 10 females, with same data as holotype; USA, Washington, Olympia, Evergreen State College , 47°04’N 123°43’W (J. Longino) 1 female from litter on college campus; Skamania Co., Wind River Crane Canopy Research Site , 45°49’14”N 121°57’W, 29.ix.2000 ( VBP) 2 females, 1 male from sifted forest floor litter in fir, hemlock forest; Oregon, Curry Co., Siskiyou National forest, Oak Flat Trail off Oak Flat Road , 19.iii.2004 ( VBP) 42°31’08”N 124°02’31”W, 3 males, 1 female from rich forest litter, oak, evergreen oak, myrtle and fir; Canada, British Columbia, Vancouver Island, McMillan Provincial Park, Cathedral Grove , 49°18’N 124°40’W, 15.iii.1996 ( VBP) 1 female from western red cedar litter, with some hemlock, 1 female from Alectoria lichen on western hemlock; same data, 18.vi.1987 (R.A. Norton & M. Clayton) 1 male from moss on bark of 1m dbh Douglas-fir in virgin cedar/fir forest ( RNC) . Paratypes deposited in the CNC, RNC, PMAE . IZ .

Diagnosis. Total length of adult 322–355 µm. Coxisternal region, pedotectum I, mentum with striae. Genital plate micropunctate with strong striae. Lamellae without translamella. Lamella (including cusp) 114–126 µm long, cusp 95–108 µm long, about 43 µm wide at level of insertion of seta le. Medial dens on lamellar cusp subequal in shape, but slightly longer than lateral dens (23–27 µm long) without teeth; lateral dens 16–19 µm long, with 2–4 teeth. Bothridial seta with narrow, setiform head, tapered distally, 110–138 µm long. Epimeral seta 3c longest, about 27 µm long; 4c weakly barbed, very short, about 6 µm long. Genital setae 2+4. Ten pairs of short, curved, weakly barbed notogastral setae 16–24 µm long, lm posteromediad of Aa, and lp anterior of A1. Tarsi monodactylous.

Description. Adult. Dimensions: Mean total length: female (n = 10) 351 µm (346–355); male (n = 10) 336 µm (322–346). Mean notogastral width: female (n =8) 232 µm (221–240); male (n =7) 224 µm (216–230).

Integument: Prodorsum, notogaster, ventral plate, anal plate, pedotectum I micropunctate. Coxisternum, lamella, pedotectum I, genal tooth, tutorium, mentum, anterior of pteromorph with striae and micropunctae ( Fig. 24). Mentum with striae in fingerprint pattern ( Fig. 24E). Genital plate micropunctate with strong striae ( Fig. 24D).

Prodorsum: Rostrum sharply pointed in dorsal aspect, with distinct medial crest; rostral margin with small medial indentation, with pair of small dens laterally, with or without small dens medially ( Fig. 24E). Lamella (including cusp) 115–126 µm long, cusp about 95–108 µm long, about 43 µm wide at level of insertion of seta le. Lamellae not connected medially; translamella absent ( Fig. 23). Lamellar cusps parallel or diverging anteromedially; maximum distance between lamellar cusps about 17 µm. Dentes on lamellar cusp short, subequal in shape, medial dens 23–27 µm long, without teeth, slightly longer than lateral dens 16–19 µm, with 2–4 teeth; number of teeth varying among specimens and on either side of same specimen ( Figs 23, 24A). Seta ro about 80 µm long, strongly barbed along length, acuminate, curved anteromedially. Seta le about 54 µm long, thick, heavily barbed, tapered. Seta in 128–132 µm long, thick (less so than le), heavily barbed, parallel; mutual distance of pair about 43 µm. Bothridial seta 110–138 µm long, with barbed, setiform head, tapered distally, same width as stalk; head directed slightly anterodorsally ( Figs 23, 24A). Exobothridial seta about 16 µm long, thin, smooth tapered.

Lateral region of podosoma: Genal tooth broad, subrectangular, rounded distally, without ventrodistal dens, with longitudinal ridge ventrolaterally ( Fig. 24C). Tutorium extending anterior of rostrum ( Fig. 24E), about 144 µm long, of which cusp about 83 µm long, rectangular, distal margin with about 7–10 teeth. Custodium about 25 µm long, tapered, short, reaching at most half length of pedotectum II ( Fig. 24D, arrow). Porose areas Al about 10 µm in diameter.

Notogaster: Length slightly shorter than width, ratio about 0.95:1. Anterior margin undulating, convex lateral of bothridium with 8–12 transverse ridges. Pteromorph with short ridges at anterior margin; anteroventral margin minutely serrate. Octotaxic system in form of 4 pairs of relatively large porose areas, 7–14 µm in diameter (Figs, 23, 30F). Ten pairs of short, curved, very weakly barbed notogastral setae present, 17–32 µm long, with c seta longest; lm posteromedial of Aa, and lp anterior of A1 ( Fig. 23). Distance setae h 1 –h 1 about 35 µm, more than 2x distance p 1 –p 1, about 15 µm ( Fig. 23). Lenticulus very diffuse, hard to discern.

Ventral Region: Epimeral setae 6–27 µm long, barbed; 3c longest seta; 4c weakly barbed, shortest seta. Genital, aggenital, anal and adanal setae weakly barbed, about 8–10 µm long. Genital setae 2+4. Postanal porose area oval, about 17 x 7 µm.

Gnathosoma : Anterior border of mentum with small transverse carina, with narrow tectum ( Fig. 24E). 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” of genua I and II about 24 µm, l” of tibia I about 31 µm, of tibia II about 12 µm. Tarsi monodactylous ( Fig. 24D).

Etymology. The specific epithet ‘sintranslamella’ refers to the absence of a translamella in this species.

Remarks. Oribatella sintranslamella is unique among species from North America in lacking a translamella. This character state is shared with O. bulanovae Kuliev, 1962 from Azerbaijan, O. colchica Krivolutsky, 1974 , and O. tenuis Csiszár and Jeleva, 1962 from Trans-Caucasus, and O. kurchevi Krivolutsky, 1974 from the Trans- Carpathians ( Shtanchaeva & Subías 2009).

Distribution and Ecology. This species is associated with rich litter in old-growth forests of western North America.