Tectoribates borealis, Behan-Pelletier, Valerie M. & Walter, David E., 2013

Behan-Pelletier, Valerie M. & Walter, David E., 2013, Phylogenetic relationships of Tectoribates: nymphal characters of new North American species place the genus in Tegoribatidae (Acari, Oribatida), Zootaxa 3741 (4), pp. 459-489 : 469-478

Tectoribates borealis sp. nov.

( Figs. 4 , 5 , 6 , 7A–E, 8A–D, 9A–D, 10A–D, 11C–E)

Material examined. Holotype: adult female, Canada, Alberta, Cypress Hills Provincial Park, Firetower Area plateau, 4.8 km S. Elkwater, 22–29.vii.1978 (E. E. Lindquist) from soil below elk and cow dung, deposited in the CNC, type number 24149. Paratypes 3 adults with same data as holotype; same location, 1 from moderately fresh buffalo dung, 1 from prairie herbage and soil below; Alberta: ABMI site OG-1650 (49.192046, -113.537695) 15 km west of Cardson, ex grassland sod, 1 June 2012, 8 females; ABMI site 1642 NE (49.17302, -112.10323) northeast of Milk River, ex litter in agricultural field, 31 May 2012, 2 females, 1 male; ABMI site 1635 NW, (49.41763, -113.99814), 5 km south-west Pincher Creek ex grass, sedge sod, 12.vi.2008, 1 female; ABMI site 1411 SW (51.41224, -112.58736) 1 km NE Cambria, ex litter in badlands, 2 males, 2 females; ABMI site OG-1054-1NW (53.57580948, -112.461479) ex litter in open, disturbed site with herbs and ferns, 25 May 2011, 1 male; 2 females; ABMI site 1362 SE, 24 May 2012, ABMI site 1362 NE (51.75812, -112.46145) 40 km north-east of Drumheller ex litter in field, 30 May 2012, 11 females, 2 tritonymphs; ABMI site 2 SW (60.00878, -112.14697) ex bog with an understory of labrador tea, sphagnum, lichen in Wood Buffalo National Park, 10 June 2009, 1 female. Paratypes deposited in the PMAE.IZ, CNC, USNM, and RNC.

Other material examined. Additional individuals from ABMI site 1411 SW (see above) and 1438 (51.10179, -111.48718) ex grass and sedge sod, 9 June 2011, were studied under the scanning electron microscope.

Diagnosis. Adult. Total length 325–340. Integument with foveae between genital and anal plates and posterolateral to genital plates. Rostral margin smooth to dentate, with medial V to U-shaped indentation. Notogaster anteriorly with distinct hexagonal pattern, visible in transmitted light. Notogastral porose areas 6–10 in diameter. Notogastral setae barbed, 16–24, with seta c longest; lm medial to Aa and lp anteromedial to A1; mutual distance of h1–h1 about 18–28, of p1–p1 37–40. Lamella about 71 long, of which cusp about 44; about 19 wide at level of insertion of seta le. Lamellar cusps effacing on prodorsum about 14 from base of prodorsum. Lamellar cleft extending posteriorly about 10 from region of fusion of lamella to prodorsum; distance between lamellae in this region (width of cleft) about 3. Lamellar cusp with two short tapered dentes, medial dens about 14 long, lateral dens shorter, about 12 long. Lamellar seta arising anteriorly on cusp, 38–44 long. Bothridial seta club-shaped, 51– 55. Seta ex about 15. Tutorium 71–81 long, of which cusp 28–32. Custodium about 15 long. Epimeral seta 1c 30– 33.

Description. Adults. Dimensions: Total length: females (n = 10) 324 (307–340). Notogastral width: females (n = 5) 205 (200–210).

Integument: Prodorsum, notogaster, pedotecta, anal plates, genital plates, coxisternum and mentum micropunctate ( Fig. 9B ); foveate between genital and anal plates and posterolateral of genital plates ( Fig. 8C , arrow). Lamellae, pedotectum, mentum, coxisternal region with fine irregular striae ( Figs. 9A, C ); tutorial cusp with distinct striae ( Fig. 9C ). Rostrum with short distinct striae close to medial indentation ( Fig. 9D ).

Prodorsum: Rostrum with distinct, convex medial crest proximally, effacing distally, rostral margin smooth to weakly dentate, with medial V to U-shaped indentation ( Figs. 9C, D ). Rostrum with deep, cerotegument-filled groove, ventral to seta ro, ( Fig. 9C ). Lamella about 71 long, of which cusp about 44; about 19 wide at level of insertion of seta le. Lamellar cusps effacing on prodorsum about 14 from base of prodorsum. Lamellar cleft extending posteriorly about 10 from region of fusion of lamella to prodorsum; distance between lamellae in this region (width of cleft) about 3. Lamellar cusp with two short, tapered dentes, medial dens about 14 long, lateral dens shorter, about 12 long ( Figs. 4 , 8A, B ). Seta ro 51–58 long, strongly barbed along length, acuminate, curved anteromedially. Lamellar seta arising anteriorly on cusp, 38–44 long. heavily barbed, acuminate distally. Seta in 67–76 long, barbed (subequally to le), acuminate; mutual distance about 28 ( Fig. 4 ). Bothridial seta club-shaped, 51–55, long, with barbed, rounded head; head directed anteromedially ( Figs 4 , 8A , 11D ). Seta ex thin, barbed, about 15 ( Fig. 8B , arrow). Dorsophragmata separate at base ( Fig. 4 ).

Lateral region of podosoma: Tutorium 71–81 long, of which cusp 28–32. Custodium about 15 long ( Figs. 8C , 9A ). Porose area Al about 8 in diameter (difficult to see because of proximal position on lateral of prodorsum).

Notogaster: Longer than wide: 1.2:1. Anteriorly with distinct hexagonal pattern ( Figs. 4 , 5 , 11C ). Octotaxic system expressed as porose areas 6–10 in diameter. Notogastral setae barbed, 16–24, with c longest; lm posteromedial to Aa and lp anterior to anteromedial of A1 ( Figs 4 , 5 ); mutual distance of h1–h1 about 24–28, of p1– p1 about 37 ( Figs. 4 , 5 ).

Ventral Region: Epimeral seta 1c more heavily barbed, and thicker than other epimeral setae, 30–33; other epimeral setae 10–16. Genital, aggenital, anal and adanal setae smooth; genital setae about 10, other setae about 7. Genital setae 3+3 or 2+4 ( Fig. 6 ). Lyrifissure iad anterolateral of anal plate. Postanal porose area (not illustrated) about 9 x 5.

FIGURES 7A–E. Tectoribates borealis sp. nov., adult female, legs I–IV and palp, all antiaxial aspect. Leg I, trochanter not illustrated. Leg II, trochanter not illustrated, with arrow to ventral tooth on genu and to proximal solenidion ω1. Leg III, trochanter not illustrated. Scale bar = 20 µm.

Gnathosoma: Axillary saccule 7 x 2. Relative lengths of setae: m>a>h.

Legs: (Figs. 7A–D). Setae l” of genu II short, spinous, more barbed than other setae on segment, about 13; l” genu I tapered, about 22. Anterodorsal spines present on tibia I lateral to solenidia φ 1 and φ 2 ( Fig. 8B ).

Description Tritonymph: Dimensions: Total length: (n = 1) 307.

Integument: Sclerotized with light brown coloration. Cerotegument of tightly packed platelets, about 2–4 in width, covering all of body and leg segments ( Figs. 10A , insert, B)).

Prodorsum: Aspis with transverse porose area posterior to setae in and bothridia. Lateral porose areas present anterior of bothridia. Seta ro finely barbed along length, tapered, about 21 long ( Fig. 10B ). Seta le barbed, phylliform, about 20 long, 10 at maximum width. Seta in barbed, phylliform, about 27 long. Mutual distance of setae ro-ro, le-le and in-in about 13, 18 and 50, respectively. Seta ex about 8 long, thick, heavily barbed, penicillate. Bothridial seta 56–59 long, barbed, clavate, head subequal in length to stalk, broader in shape than that of adult.

Gastronotic Region: Integument without sculpturing; orientation of plicae more transverse anteriorly, more longitudinal posteriorly ( Fig. 10A ). Gastronotal setae of c, d, l, h and p series about 14–20 long, with seta c3 shortest seta. Mutual distance setae da-da, dm-dm and dp-dp 41, 36 and 15, respectively.

Ventral Region: Medial margins of epimeral plates weakly defined. Epimere I with narrow mentotectum developed laterally. Epimeral, genital, aggenital, anal and adanal setae smooth, acuminate, about 10 long. Porose integument surrounding opening of opisthonotal gland not evident (possibly because area covered by cerotegument). Epimeral setation 3-1-2-3. Genital, aggenital, anal and adanal setae 5, 1, 2, 3, respectively.

Gnathosoma: Axillary saccule present. Palpal eupathidium acm attached to solenidion along distal half of solenidial length.

Legs: Setae and solenidia as for tritonymph of Tectoribates alcescampestris ( Table 1 ). Proral setae of tarsus I appear eupathidial. Subunguinal seta of tarsus I of normal form and inserted proximal to antelateral pair as in adult. Porose areas present on femora I to IV. Distal setae on tarsi I–IV blunt distally. Setae d on femora I to IV barbed, phylliform ( Fig. 10D ). Tibiae I and II and genu I with seta l’ barbed, tapered, partially phylliform, l” more spinose. Solenidion and coupled seta d on tibia I on anterodorsal tubercle ( Fig. 10D ). Solenidion φ on tibia II and III subequal in length to seta d; solenidion φ on tibia IV 4 /5 length seta d. Solenidia δ on genua I, II and III 4 /5 to subequal length seta d.

Etymology. The specific epithet borealis is from the Greek meaning ‘northern’ and refers to the northern distribution of this species.

Remarks. This species is similar to two Mongolian species, Tectoribates mongolicus and T. deserticola , in having a notogaster with the hexagonal pattern anteriorly and porose areas. It differs from both species in interlamellar setae reaching the tip of the lamella (reaching at most to insertion of seta le in the Mongolian species) and in well developed medial and lateral dens on the lamellar cusp (medial and lateral dens short and weakly developed in the Mongolian species). It differs from T. mongolica in having shorter notogastral setae and from T. deserticola in having elongate, club-like, rather than short, globular bothridial setae.

The tritonymph of this species can be easily distinguished from that of Tectoribates alcescampestris , described above, by the phylliform shape of its setae p2 and p3 (vs. barbed, tapered) and phylliform seta d on femur IV (vs barbed and tapered).

Tectoribates borealis has been found in open habitats, primarily native prairie, badlands and pastures in southern Alberta, but we have one specimen from a bog in Wood Buffalo National Park, in the extreme north of the province. Gravid females carry up to 3 large eggs. Gut contents are composed primarily of dark brown fungal hyphae and spores. The association of immatures with adults was addressed under the Discussion following the generic diagnosis (See above, Remark 4).

Three male specimens almost identical to the description given above are known from Florida, USA (housed in the RNC). They differ in that the medial dens of the lamellar cusp is subequal to the lateral dens. We hesitate to consider these specimens members of Tectoribates borealis , until there are more records of the genus known from Eastern North America.

Figures

FIGURE 4. Tectoribates borealis sp. nov., adult female, dorsal aspect, legs not illustrated, except for proximal segments of leg I. Scale bar = 50 µm.

FIGURE 5. Tectoribates borealis sp. nov., adult female, notogaster. Scale bar = 50 µm.

FIGURE 6. Tectoribates borealis sp. nov., adult female, ventral aspect, legs not illustrated. Scale bar = 50 µm.

FIGURES 9 A – D. Tectoribates borealis sp. nov., scanning electron microscope images of adult female from Alberta, Canada; A, ventral region showing discidium, custodium and foveae on lateral of ventral plate; B, detail of foveae on notogaster, showing foveae mostly plugged with cerotegument; C, prodorsum, anterolateral aspect, with arrow to small teeth lateral to solenidia on tibia I; D, rostrum, laterofrontal aspect, with arrow to proximal solenidion on tarsus II. Scale bar: A, B, C = 10 µm, D = 1 µm.

FIGURES 8 A – D. Tectoribates borealis sp. nov., scanning electron microscope images of adult female from Alberta, Canada, A. habitus dorsal; B, prodorsum, with arrow to small teeth lateral to solenidia on tarsus I, and arrow to exobothridial seta; C, habitus ventral, with arrow to foveae between genital and anal plates; D, gnathosoma, with arrow to band of tubercles on anterior of coxisternal region. Scale bar: A, B, C = 20 µm, D = 10 µm.

FIGURES 11 A – F. Differential interference contrast microscope images of adults: A, B: Tectoribates alcescampestris sp. nov., adult female; A, prodorsum, dorsal aspect, with arrow to lamellae effacing on prodorsum medially (4 layers combined); B, gnathosoma with arrow to axillary saccule; C – E: Tectoribates borealis sp. nov., C, notogaster, anterior, showing pattern in lenticular region; D, prodorsum, with arrow to lamellae effacing on prodorsum medially (3 layers combined); E, pedotectum I, with arrow to posteroventral region; F, Tectoribates campestris sp. nov., notogaster, anterior, showing pattern in lenticular region; insert showing notogastral saccule Sa. Scale bars: A, D = 50 µm, B = 10 µm, C, E, F = 15 µm.

FIGURES 10 A – D. Tectoribates borealis sp. nov., scanning electron microscope images of tritonymph from Alberta, Canada; A, habitus, dorsolateral aspect, with insert of cerotegumental platelets bottom right; B, habitus, ventrolateral aspect, insert of opisthonotal gland opening upper left; C, palptarsus, antiaxial aspect; D, detail of legs I and II, antiaxial aspect, with arrow to phylliform seta d on femur III and coupled seta d on tibia I. Scale bar: A, B = 50 µm, C, = 1 µm, D = 10 µm.