Apostenus ducati Bennett, Copley & Copley

Bennett, Robb, Copley, Claudia & Copley, Darren, 2013, Apostenus ducati (Araneae: Liocranidae) sp. nov.: a second Nearctic species in the genus, Zootaxa 3647 (1), pp. 63-74 : 64-68

Apostenus ducati Bennett, Copley & Copley sp. nov.

Figs. 1–18

Type material. Male holotype and female allotype from CANADA, British Columbia: south-facing open rocky east crest of Evening Ridge ( Fig. 17 ; ~ 8.5 km southeast of Nelson), Kootenay River drainage, 49°27'37"N 117°10'44"W, ~ 1900 m, 31.vii.2011, C. Copley, D. Copley, and R. Bennett (CAS) .

Paratypes. CANADA: British Columbia: Flathead River drainage: 6♂, 2♀, 22 juveniles, scree and boulders at old gas exploration site, Cabin Creek Forest Service Road, 49°06'04"N 114°37'24"W, 1450 m, 16.viii.2012, R. Bennett, C. Copley, D. Copley, and R. Nelson (AMNH) ; 2♂, 9♀, 4 juveniles, scree and boulders at old road cut, Cabin Creek Forest Service Road, 49°05'58"N 114°39'41"W, ~1500 m, 16.viii.2012, R. Bennett, C. Copley, and D. Copley (CAS) ; 3♀, 2 juveniles, scree slope, Flathead Sage Forest Service Road (south side Commerce Peak), 49°07'43"N 114°24'38"W, 1385 m, 14.viii.2012, R. Bennett, C. Copley, and D. Copley (NMNH) ; 1♀, Kishinena Forest Service Road (southwest slope of Miskwasini Peak), 49°01'45"N 114°23'42"W, ~ 1400 m, 15.viii.2009, C. Copley, D. Copley, and J. Miskelly (RBCM, accession # ENT012- 012551) ; 1♂, 1 juvenile, Kishinena Forest Service Road (downstream from Rose Canyon), 49°03'41"N 114°17'00"W, 1350 m, 14.viii.2012, R. Bennett, C. Copley, and D. Copley (NMNH) ; 6♂, 7♀, 10 juveniles, scree slope beside access road, east side Mount Hefty ( Fig. 17 ), 49°00'38"N 114°33'38"W, 1840 m, 15.viii.2012, R. Bennett, C. Copley, and D. Copley (RBCM, accession # ENT012- 012547) ; 1♀, nr fire lookout, north end of Mount Hefty, 49°00'59"N 114°33'52"W, 2045 m, 15.viii.2012, R. Bennett, C. Copley, and D. Copley (AMNH) ; Kootenay River drainage: 1♂, 2♀, 8 juveniles, south-facing Abies lasiocarpa / Picea englemannii open woodland on crest of Cornice Ridge (north slope of Kootenay Pass), 49°03'51"N 117°03'00"W, ~ 1900 m, 11.viii.2009, C. Copley, D. Copley, and J. Miskelly (RBCM, accession # ENT012- 012552) ; 1♀, 6 juveniles, south-facing open rocky crest of Evening Ridge (~ 8.5 km southeast of Nelson), 49°27'37"N 117°10'44"W, ~ 1900 m, 31.vii.2011, R. Bennett, C. Copley, and D. Copley, (RBCM, accession # ENT012- 012550) ; 1♂, 1♀, southeast-facing boulder field on north slope of Gray Creek Pass (~ 14 km southeast of Crawford Bay), 49°35'22"N 116°40'56"W, ~ 2350 m, 29.vii.2011, R. Bennett, C. Copley, and D. Copley (RBCM, accession # ENT012- 012549) ; 1♀, 1 juvenile, Lakit Lookout Trail, Lakit Peak, northeast of Fort Steele, 49°43'09"N 115°35'01"W, 2020 m, 12.viii.2012, R. Bennett, C. Copley, and D. Copley (CNC) ; 1♂, 1♀, open rocky crest of Swamp Basin Ridge (Darkwoods National Wildlife Area, ~ 1.5 km southwest of Mount Hewlett), 49°13'49"N 117°01'42"W, ~ 2200 m, 10.ix.2011, R. Bennett, C. Copley, and D. Copley (CNC) ; Slocan River drainage: 4 juveniles, open rocky southeast ridge of Idaho Peak (~ 5 km west of Sandon), 49°58'14"N 117°17'57"W, ~ 2200 m, 29.vii.2011, R. Bennett, C. Copley, and D. Copley (RBCM, accession # ENT012- 012548) . U.S.A.: Montana: Glacier Co. 1♀, Glacier National Park, scree slope on Many Glacier Road near Swift Current Lake, 48°48'00"N 113°38'98"W, ~ 2300 m, 17.ix.2003, D. Wytrykush, P. Paquin (SDSU) . Washington: Okanogan Co. 5♀, shaded talus slope in Finley Canyon (~ 13 km southeast of Twisp), 48°19'48"N 119°57'19"W, ~ 850 m, 14.vi.1981, R.L. Crawford, J.P.P., M.A.P. (UWBM) ; 1♀, north slope of McLoughlin Canyon, (~ 4 km south of Tonasket), 48°40'01"N 119°25'51"W, ~ 500 m, 24.iv.1976, R.L. Crawford (UWBM) .

Etymology. The species name is a patronym (genitive, masculine) honouring the Ducati motorcycle marque and refers to the characteristic speed, sprightliness, and maneuverability with which specimens of A. ducati evade pursuit. We have found them to be very difficult to capture, even in cool weather, perhaps explaining in part why this species has not been recorded previously.

Diagnosis. Specimens of Apostenus are distinguished from all other spiders by the combined presence of distinctive multiple pairs of overlapping elongate macrosetae lateroventrally on the tibiae and metatarsi of legs I and II ( Figs. 1, 2 ) and, at the tip of each leg, of two tarsal claws each with an adjacent single flattened tenent macroseta (Figs. 10, 11; Ubick & Vetter 2005, fig. 8). Although these characters are sufficient to distinguish Apostenus , further characters for the separation of the genus from other liocranids were presented by Bosselaers (2009).

Sexual and somatic characteristics separate A. ducati from A. californicus, the only other species of Apostenus known from the Nearctic region. The posterior portion of the median epigynal lobe (median septum of Bosselaers & Jocqué (2002) and Bosselaers (2009)) in female A. ducati is broadly triangular and extends posteriorly almost to the epigastric groove ( Figs. 7 , 12 ). In A. californicus the median epigynal lobe is broadly truncate posteriorly and does not extend to the epigastric groove (Ubick & Vetter 2005, fig. 25). In male A. ducati the embolus is a simple short curved spur ( Figs. 4–6 ) and the sickle-shaped median apophysis is elongate and thin ( Figs. 4, 5 ). In A. californicus the embolus is also short and curved but is relatively more complex with a grooved surface ventrally and angular modifications proximally and distally (Ubick & Vetter 2005, figs. 22–24, 28, 30) and the sickle-shaped median apophysis is relatively shorter and thicker (Ubick & Vetter 2005, figs. 23, 28). In addition, in A. californicus all tarsi are subsegmented and tarsus I possesses a lateroventral row of paired spatulate setae (Ubick & Vetter 2005, figs. 3, 4). In A. ducati tarsi are subsegmented only on legs III and IV, and tarsus I also possesses a lateroventral row of paired setae, although these are not spatulate but resemble diminutive versions of the paired lateroventral macrosetae characteristic of tibiae and metatarsi I and II. Finally, specimens of A. californicus are relatively dark-coloured and have banded legs; those of A. ducati are relatively pale with unbanded legs.

Description. Carapace, sternum, and legs light greyish brown, not patterned except for faint dark maculations radiating from region of thoracic groove ( Figs. 1 , 13 ). Carapace low, unmodified, piriform, with scattered setae (most obvious around eyes and clypeus). Eyes ( Fig. 3 ): ALE largest, AME smallest, about 1/3 diameter of ALE, PE subequal, slightly smaller than ALE, in anterior view AER straight and PER slightly procurved. Chelicerae unmodified, lightly setose; prolateral and retrolateral fang furrows each with a few small denticles obscured by setae. Labium rounded, nearly twice as wide as long; endites quadrate, slightly convergent, slightly more than twice as long as labium, each with serrula on anterior retrolateral margin. Sternum shield-shaped, truncate anteriorly, with posterior extension between coxae IV; lightly setose, setae denser at lateral margins and at posterior intercoxal projection.

Leg formula 4123. Each leg tarsus with a pair of distal pectinate claws, each claw with an adjacent distinctive flattened tenent macroseta ( Figs. 10, 11 ); tarsi subsegmented only on legs III and IV, tips of tarsi III and IV curved ventrally (most conspicuously in males). Leg tarsi, metatarsi, and tibiae dorsally with two rows of scattered trichobothria ( Figs. 1, 2 , 13 ). Leg macrosetae (other than tarsal tenent macrosetae): I—metatarsus v2-2 -2-0, tibia v2-2 -2-2-2-0, patella d0-0-1, femur d0-1-1-0, p0-1(or 2)-0; II—metatarsus v2-2-2-0, tibia v2-2-2-2-0, patella d0-0- 1, femur d0-1-1-0; III—metatarsus v2 -0-1(or 2), p0-1-0, r0-1-0; tibia d1-0-1-0, v2 (or 1)-2; patella d0-0-1, femur d0-1-1-1(or 2); IV—metatarsus v0-2-0-2, p1-1-1, r1-1-1, tibia d1-0-1-0, v0-2-2-0, p0-1-0, r0-1-1-0, femur d 0-1-1- 2(or 3).

Abdomen without scuta, dorsally light grey with longitudinal series of transverse pale markings appearing as chevrons, bars, or paired spots (dorsal pattern may be obscure) ( Figs. 1 , 13 ); ventrally pale except light grey around spinnerets, not patterned. Abdomen and spinnerets relatively densely setose; setae especially dense in female epigastric area where they largely obscure epigynum ( Fig. 15 ); male ventral abdominal setae relatively short and stout. Colulus reduced, represented by two setae. Spinnerets unmodified: compact, short, conical with terminal segments of ALS and PLS about ¼ length of basal segments; ALS largest, slightly separated; PMS contiguous, about ⅔ length and ½ width of ALS; PLS separated by width of PMS, slightly shorter than and about ⅔ width of ALS.

Male. Holotype and 18 paratypes examined. Total length 3.45 (2.52–3.45; 2.97+0.31), CL 1.35 (0.85–1.41; 1.05+0.17), CW 1.11 (0.71–1.11; 0.85+0.14), SL 0.90 (0.58–0.93; 0.69+0.12), SW 0.75 (0.46–0.75; 0.59+0.08). Cymbium simple. Genital bulb with extensive tegulum (with sperm duct often visible), elongate, sickle-shaped median apophysis, no conductor, and terminating in a short, stout, curved embolus. Retrolateral tibial apophysis short (length slightly less than tibia width), curved, pointed, and anteriorly projecting ( Figs. 4–6 , 14 ).

Female. Allotype and 36 paratypes examined. Total length 4.83 (2.88–4.83; 4.01 + 0.43), CL 1.53 (0.94–1.74; 1.28 + 0.23), CW 1.26 (0.76–1.41; 1.06 + 0.17), SL 1.05 (0.62–1.14; 0.83 + 0.15), SW 0.87 (0.55–0.96; 0.70 + 0.11). Epigynum usually obscured by setae ( Fig. 15 ); broad, sagittate median epigynal lobe visible in ventral view with setae removed ( Figs. 7 , 12 ); copulatory openings located at lateral points of median epigynal lobe. In cleared dorsal or ventral view ( Figs. 8, 9 ) vulva with prominent pair of reniform spermathecae, very short inconspicuous copulatory ducts, and short curved fertilization ducts.

Figures

FIGURES 1–3. Apostenus ducati sp. nov., somatic features, female: 1, habitus, dorsal; 2, left leg I, tibia and metatarsus, prolateral; 3, eye region, anterior. Scale bars = 1.5 mm (Fig. 1) and 0.3 mm (Figs. 2, 3).

FIGURES 4–9. Apostenus ducati sp. nov., genitalic characters: 4, male left pedipalpal tibia and tarsus, ventral; 5, same, retrolateral; 6, same, tarsus, prolateral; 7, female, epigynum with setae removed, ventral; 8, same, vulva (cleared), ventral; 9, same, dorsal. Abbreviations: CO = copulatory opening, E = embolus, FD = fertilization duct, MA = median apophysis, ML = median epigynal lobe, RTA = retrolateral tibial apophysis, SD = sperm duct, Sp = spermatheca, T = tegulum. Scale bars = 0.25 mm (Figs. 4–6) and 0.1 mm (Figs. 7–9).

FIGURES 10–12. Apostenus ducati sp. nov., female: 10, tarsus I claws and tenent macrosetae, anterior prolateral; 11, same, retrolateral; 12, epigynum with setae removed, ventral. TC = tarsal claw, TCT = tarsal claw teeth, TM = tenent macroseta, TMB = base of tenent macroseta. Scale bars = 0.05 mm.

FIGURES 13–15. Apostenus ducati sp. nov., habitus and genitalic characters: 13, male, dorsal; 14, left pedipalpal tibia and tarsus, ventral; 15, epigynum with setae in place, ventral.

FIGURE 16. Apostenus ducati sp. nov., Canada and U.S.A. collection localities. AB = Alberta, BC = British Columbia, ID = Idaho, MT = Montana, WA = Washington.

FIGURES 17, 18. Apostenus ducati sp. nov., collection sites: 17, type locality, crest of Evening Ridge, BC, 49°27´37´´N 117°10´44´´W, ~ 1900 m, 31.vii.2011, view to southwest, Ymir Mountain in middle background; 18, narrow scree slope on east side of Mount Hefty, BC, 49°00´38´´N 114°33´38´´W, 1840 m, a site where A. ducati was relatively abundant, 15.viii.2012, view to west, upslope

FIGURES 1 – 3. Apostenus ducati sp. nov., somatic features, female: 1, habitus, dorsal; 2, left leg I, tibia and metatarsus, prolateral; 3, eye region, anterior. Scale bars = 1.5 mm (Fig. 1) and 0.3 mm (Figs. 2, 3).

FIGURES 4 – 9. Apostenus ducati sp. nov., genitalic characters: 4, male left pedipalpal tibia and tarsus, ventral; 5, same, retrolateral; 6, same, tarsus, prolateral; 7, female, epigynum with setae removed, ventral; 8, same, vulva (cleared), ventral; 9, same, dorsal. Abbreviations: CO = copulatory opening, E = embolus, FD = fertilization duct, MA = median apophysis, ML = median epigynal lobe, RTA = retrolateral tibial apophysis, SD = sperm duct, Sp = spermatheca, T = tegulum. Scale bars = 0.25 mm (Figs. 4 – 6) and 0.1 mm (Figs. 7 – 9).

FIGURES 10 – 12. Apostenus ducati sp. nov., female: 10, tarsus I claws and tenent macrosetae, anterior prolateral; 11, same, retrolateral; 12, epigynum with setae removed, ventral. TC = tarsal claw, TCT = tarsal claw teeth, TM = tenent macroseta, TMB = base of tenent macroseta. Scale bars = 0.05 mm.