Scyletria inflata Bishop & Crosby 1938

Patrick, Brian, Dupérré, Nadine & Dondale, Charles D., 2008, Review of the Nearctic genus Scyletria Bishop & Crosby (Araneae, Linyphiidae), with a transfer of S. jona to Mermessus O. Pickard-Cambridge, Zootaxa 1744, pp. 31-40 : 32-35

Scyletria inflata Bishop & Crosby 1938

( Figs. 1–4 , 12 )

Scyletria inflata Bishop & Crosby 1938:89 , Pl. 7, Figs. 72–74 (male); Bélanger & Hutchinson 1992:38; Aitchison-Benell & Dondale 1992:224; Paquin et al. 2001:19; Paquin & Dupérré 2003:118, Figs. 1233–1235 (male, female); Draney & Buckle 2005:155, Figs. 35.276, 35.308 (male); Dupéré [sic] et al. 2006:152, Figs. 20, 21 (female). Cephalethus birostrum Chamberlin & Ivie 1947:30 , Fig. 21. Female paratype only, misidentified.

Savignia birostra: Buckle et al. 2001:139 (part); Platnick 2007 (part).

Type specimens. Holotype ɗ, EXAMINED. UNITED STATES OF AMERICA: New York: Raquette Lake, [43.9°N, 74.6°W], June 11, 1927, coll. C.R. Crosby ( AMNH). Specimen in poor condition, with all legs from femur to tarsus missing, left palpus missing, and cephalothorax separated from abdomen.

Paratype Ψ, Cephalethus birostrum . EXAMINED. Alaska: Matanuska [61°N, 149°W], 23 May, 1945, colls. J.C. Chamberlin & Alan Linn ( AMNH).

Other material examined. UNITED STATES OF AMERICA: North Carolina: Summit of Mt. Mitchell [35.77°N, 82.26°W], 12 October 1923, 3 ɗɗ ( AMNH). CANADA: Alberta: Elkwater Lake, Cypress Hills Provincial Park [49.65°N, 110.30°W], 7 August 1978, Sedges, coll. E.E. Lindquist, 1 Ψ ( CNC); Elkwater Lake, Cypress Hills Provincial Park [49.65°N, 110.30°W], 5–15 August 1978, coll. E.E. Lindquist, 1 Ψ ( CNC). Manitoba: Cowan Creek, Duck Mountain Provincial Park [52.02°N, 100.65°W], 2 June 1980, emergence trap, coll. Flannagan, 1 Ψ ( CNC); Riding Mountain National Park: Swanson Spring [50.68°N, 99.82°W], 20 June 1979, coll. D.B. Lyons, 1 ɗ ( CNC); Riding Mountain National Park: Jackfish Creek [50.75°N, 100.82°W], 15 August 1979, sedges, colls. J & M Redner, 1 Ψ ( CNC); Riding Mountain National Park: Bison enclosure [55.47°N, 98.45°W], 30 May–19 June 1979, coll. D.B. Lyons, 1 ɗ ( CNC); Riding Mountain National Park: North Shore Drive [50.65°N, 99.97°W], 2 August 1979, coll. S.J. Miller, 2 ɗɗ ( CNC); Riding Mountain National Park: Wasagaming [50.65°N, 102.62°W], 29 August 1979, moss, colls. J. & M. Redner, 1 ɗ 1 Ψ ( CNC). New Brunswick: 25 km SW of Bathurst [47.62°N, 65.68°W], 19–30 June 1984, Balsam Fir foliage, coll. B.L. Cadogan, 1 Ψ ( CNC); Green River, 30 miles N of Edmunston [47.32°N, 68.15°W], 2–9 July 1963, litter, coll. T.R. Renault, 3 ɗɗ ( CNC); Priceville, 12 miles N of Boiestown [46.52°N, 66.28°W], 22 August 1968, under stone, coll. T.R. Renault, 1 Ψ ( CNC); Green River, 30 miles N of Edmunston [47.32°N, 68.15°W], 26 June 1968, coll. T.R. Renault, 1 Ψ ( CNC); Fredericton [45.97°N, 65.45°W], 9–12 July 1970, Balsam Fir foliage, coll. T.R. Renault, 1 ɗ ( CNC). Newfoundland: The Arches [50.12°N, 57.65°W], 7 August 1984, in grass and moss, coll. G. Costello, 1 Ψ ( CNC). Northwest Territories: Fort Simpson [61.82°N, 121.35°W], 15 June 1972, litter, coll. A. Smetana, 1 ɗ 1 Ψ ( CNC). Nova Scotia: Cape Breton Highlands National Park: Lone Shieling [46.82°N, 60.80°W], pan trap, 18 June–11 July 1983, coll. R. Vockeroth, 1 ɗ ( CNC); Cape Breton Highlands National Park: sandy beach [46.82°N, 60.80°W], 22 June 1983, coll. Y. Bousquet, 1 Ψ ( CNC); Cape Breton Highlands National Park: Pleasant Bay [46.82°N, 60.80°W], 6–17 June 1984, coll. L. Masner, 1 ɗ ( CNC); Coldbrook, Kings County [45.07°N, 64.58°W], 8 July 1958, apple foliage, coll. C.D. Dondale, 1 Ψ ( CNC). Ontario: Spruce River, 42 miles N of Hurkett [49.28°N, 88.85°W], 17 August 1972, moss, coll. E.E. Lindquist, 1 Ψ ( CNC). Québec: St. Méthode, near Lac St. Jean [48.73°N, 72.42°W], 13 July 1982, litter, colls. C.D. Dondale & J. Redner, 1 Ψ ( CNC); St. Hippolyte [45.93°N, 79.02°W], 10 June 1975, coll. R. Rochon, 1 Ψ ( CNC); St. Hippolyte [45.93°N, 79.02°W], 25 June 1975, coll. R. Rochon, 1 ɗ ( CNC); Îles de la Madeleine: Grosse Île [47.5°N, 61.67°W], 1 July 1985, sedges, coll. L. LeSage, 1 Ψ ( CNC).

Diagnosis. It is difficult to diagnose Scyletria properly until its nearest relatives are known. The data available in older original descriptions are often insufficient and do not provide enough details with regard to the embolic division configuration and sclerites. Furthermore, as Miller & Hormiga (2004:425) remarked, "Identification of sclerites in the linyphiid embolic division appears to be more difficult than first thought.” As such, the diagnosis and the description of the genus Scyletria are represented by the type species characteristics provided below.

Scyletria inflata is distinguished from other erigonine species by the following characters: male palpal tibia with two apophyses separated by a deep fissure ( Fig. 4 ); embolic division with long tailpiece bearing a sharp, transparent spine basally ( Fig. 3 ), radix folded, bearing a large outgrowth (R Out) with fringed edges ( Figs. 1, 3 ). Epigynum characterized by a pair of blunt prominences separated by a deep indentation (Dupéré [sic] et al. 2006: Figs. 20–21).

Description. Male: Male from Cape Breton Highlands National Park, Nova Scotia, Canada: total length 1.91 mm; carapace 0.91 mm long, 0.62 mm wide. Carapace dark orange, evenly convex at sides, steeply ascending from posterior margin to dorsal groove, then convex to posterior eye row, lacking lobes and pits; clypeus somewhat protruding. Posterior eye row procurved; anterior eye row recurved; eyes subequal in diameter; anterior lateral eyes and posterior lateral eyes touching. Chelicerae yellow, with about 18 stridulatory ridges; promargin with 5 small teeth, and retromargin with 3 denticles. Sternum mid-brown, shiny. Abdomen dark grey. Legs yellowish; tibial dorsal macrosetae 2221; TmI circa 0.40; TmIV absent; coxa IV with stridulatory pick. Palpal tibia black, with 2 dorsal apophyses of about equal length ( Fig. 4 ); mesal of these apophyses bifid at tip; apophyses separated by deep fissure ( Fig. 4 ). Paracymbium broad, flat, with distal hook, proximal end bearing two setae ( Fig. 2 ); embolic division with radix and tailpiece without break ( Fig. 3 ); radix long and folded, with large outgrowth (R out) with fringed edges ( Fig. 3 ); tailpiece long, sac-shaped, with shallow excavation on mesal margin, bearing a long, sharp, transparent spine basally ( Fig. 3 ); embolus short and flat; anterior radical process and embolic membrane present ( Figs. 1, 2 ).

Female: Female from Ste. Méthode, Québec, Canada: total length 1.83 mm; carapace 0.87 mm long, 0.46 mm wide. Carapace, sternum, abdomen and legs essentially as in male. Cheliceral retromargin with 10 minute denticles. A full description with illustrations of the female is given in Dupéré [sic] et al. (2006: Figs. 20–21).

Variation. Males: Six males gave the following (mean ± 1 SD): total length 1.64 ± 0.16 mm; carapace 0.81 ± 0.06 mm long, 0.60 ± 0.03 mm wide. Carapace dull yellow to dark yellow, dull reddish in some specimens. Sternum often suffused with dark grey. Abdomen usually dark. Legs yellow to pale orange.

Females: Five females gave the following (mean ± 1 SD): total length 1.65 ± 0.16 mm; carapace 0.68 ± 0.05 mm long, 0.48 ± 0.05 mm wide (from Dupéré [sic] et al. 2006). See Dupéré [sic] et al. 2006 for additional details.

Natural history. Captured in a variety of habitats (summarized in Dupéré [sic] et al. 2006), the species is an epigeal spider from the boreal region of North America with extension southward in the Appalachian Mountains. Little else is known of its natural history.

Distribution. Fig. 12 . USA: Alaska, North Carolina, New York. CANADA: Alberta, Manitoba, New Brunswick, Newfoundland, Northwest Territories, Nova Scotia, Ontario, Québec, Saskatchewan.

Figures

FIGURE 12. Geographic distribution of Scyletria inflata Bishop & Crosby 1938 (filled circles) and Mermessus jona (Bishop & Crosby 1938) new combination (crosses).

FIGURES 1 – 4. Scyletria inflata Bishop & Crosby 1938. 1. Male palpus, ventral view; 2. Male palpus, retrolateral view; 3. Expanded male palpus, schematic illustration; 4. Male palpal tibia, dorsal view. Scale bars = 0.1 mm.