Oaphantes pallidulus ( Banks, 1904 )

Paquin, P., Dupérré, N., Buckle, D. J. & Ubick, D., 2020, Caves as a key habitat for rare and endemic species of the west coast of North America: a taxonomic revision of the spider genus Oaphantes (Araneae Linyphiidae), Zootaxa 4819 (2), pp. 349-363 : 351-353

Oaphantes pallidulus ( Banks, 1904)

( Figs 1–8 , 25 )

Bahyphantes pallidula Banks, 1904 b: 346 , fig. 45 (Description of male).

Oaphantes pallidulus Chamberlin & Ivie, 1943: 7 , fig. 10–11. (Transferred male from Bathyphantes , described female), Briggs & Ubick, 1988: 44, Buckle et al., 2001: 243, Ubick, 2001: 10, Paquin et al., 2009a: 51–53, Elliott et al., 2017: 181.

Type material.— Bathyphantes pallidula Banks , EXAMINED. Holotype male. Label 1: “ Bathyphantes pallidula Banks type. Claremont [W 117˚, N 36˚], Los Angeles CA, U.S.A. Baker (Nathan Banks Coll.) MCZ 22485”. Label 2: “(Nathan Banks Coll.)”. There is some ambiguity about the type depository, which Chamberlin & Ivie (1943: 8) give as CAS. Banks (1904: 232) stated that the holotypes of the 38 new species will be divided between the two institutions but did not indicate which species go where.

Other material.— USA: California: San Mateo Co.: San Bruno Mountain, N slope nr Guadaloupe Industrial Park , 11.xii.1998, coastal scrub with chaparral, under sandstone (graywacke) rock, 1♂, D. Ubick & T. Briggs ( CDU); Santa Clara Co.: Stanford [sic, coordinates and original paper mention Santa Cruz, see remark] 122.37 nw., 19.xii.1928, 1♂, J.C. Chamberlin ( AMNH); Santa Cruz Co., Dolloff Cave, Cave Gulch , 28.viii.1963, hand collect- ing, 2♀, R.E. Graham ( AMNH); same, 7.v.1988, 1♀, D. Ubick, T. Briggs, W. Savary & W. Rauscher ( CDU); IXL Cave , 28.viii.1963, under wood on floor, hand collecting, 1♂ 3♀, R.E. Graham ( AMNH); Santa Cruz City Cave , 31.i.1960, under wood on floor, hand collecting, 2♀, R.E. Graham ( AMNH); Stump Cave, Cave Gulch , 27.vii.2001, hand collecting, 1♀, D. Ubick, T. Briggs ( CDU); same, 22.i.2005, in cave along walls in webs, hand collecting, 2♂ 2♀, P. Paquin & D. Ubick ( CPAD); same, 26.vii.2010, 1♀, J.M. Ledford ( CDU); Monterey Co., Pacific Grove , [121°N, 36°W on label] [36°37’N, 121°54’W] 15.viii.1931, 1♂, W. Ivie ( AMNH); San Benito Co., 1400 Hwy 101, Monterey Vacation RV Park , below Pinacate Peak , north-facing oak hillside south of park, [36.86023 - 121.61266] 11.iii.2006, 1 ♀, 90m altitude, under boulders, M. Hedin et al. ( CPAD).

Diagnosis.— Males and females of O. pallidulus most resemble those of O. prometheus n. sp. in genitalic structures (male palp with large terminal apophysis (TA) and female with long scape (SC)) (compare Figs 3, 6 with 19, 22) but differ by their larger size and the presence of eyes ( Fig. 2 ). Additionally, males are distinguished by a larger paracymbium bearing a longitudinal keel curving apically ( Fig. 3 ) and an embolus (E) harbouring a spike on basal half ( Fig. 4 ). Females are distinguished by their dome-shaped anterior epigynal margin ( Fig. 6 ), a long scape (SC) slightly enlarging at tip that nearly reaching the tip of the abdomen ( Figs 6, 8 ). Males are distinguished from O. cryophilus n. sp. by their large terminal apophysis ( Figs 3, 4 ), absent in the latter species ( Figs 11, 12 ); females are distinguished by their curved secondary spermathecae ( Fig. 15 ), straight in O. pallidulus ( Fig. 7 ).

Description.— Male (n=5): Total length: 2.17–2.77; carapace length: 1.09–1.36; carapace width: 0.82–1.02; carapace smooth, shiny, light yellow orange (130M), slightly raised in cephalic region, bearing 2–4 erect setae along midline. Sternum light yellow orange (130M). Chelicerae light orange (137M), promargin carinated with 4 teeth and a mastidion ( Fig. 2 ), retromargin with 4 denticles, presence of setae-tipped tubercles on cheliceral surface. Cheliceral stridulatory organ visible with ∼ 20 striae. Endites light yellow orange (130M) with a single setose tubercle ( Fig. 1 ). Abdomen off-white (7500M), sub-cylindrical, pointed apically, covered with long semi-erect setae; ventral surface of abdomen with oval striated epigastric plates. Legs long and slender, light yellow orange (130M), formula 1-4-2-3; tibia I–IV with 2 long dorsal macrosetae; metatarsus I with dorsal trichobothrium, Tm I 0.28, Tm IV absent; coxae IV with stridulatory pick. Palpal femur with stridulatory pick. Male palp: paracymbium complex (P) with a longitudinal keel curving apically, a proximal pocket (PPO), a proximal protuberance bearing three long setae, and one short seta on its apical part ( Fig. 3 ); embolus (E) long, smooth, bearing a spike on basal half, curving and extending beyond the cymbium ( Figs 4, 5 ); embolic membrane (EM) large and long ( Figs 4, 5 ); terminal apophysis (TA) basally well sclerotized with an embossed surface, apical part membranous and acuminate ( Figs 4, 5 ); lamella characteristica (LC) slender and twisted ( Figs 4, 5 ); 1 tooth on distal suprategular apophysis (SA) ( Figs 4, 5 ); retrolateral tibial apophysis (RTA) present ( Fig. 3 ).

Female (n=5): Total length: 2.53–3.15; carapace length: 1.16–1.33; carapace width: 0.87–0.97; carapace colouration as in male, not elevated in cephalic region, bearing 4–5 erect setae along midline. Colouration of sternum and chelicerae as in male, promargin of chelicerae with 4 large teeth and 1 medium sized tooth, retromargin with four denticles, presence of setae-tipped tubercles on cheliceral surface. Cheliceral stridulatory organ visible with ∼ 15 striae. Endite colouration as in male, without setose tubercle. Abdomen colouration as in male, sub-cylindrical, pointed apically, covered with long semi-erect setae; ventral surface of abdomen bearing oval striated epigastric plates. Legs long and slender, light yellow orange (130M), formula 1-4-2-3; tibia I–IV with 2 long dorsal macrosetae; metatarsus I with dorsal trichobothrium, Tm I 0.24–0.27, Tm IV absent; coxae IV with stridulatory pick. Palpal femur with stridulatory pick. Epigynum characterized by the broad, dome-shaped anterior margin of scape ( Fig. 6 ), gradually narrowing in a long scape (SC), slightly enlarging apically and almost reaching the apex of the abdomen ( Fig. 8 ); spermathecae (S) oval, secondary spermathecae (SS) elongate, straight and directed posteriorly ( Fig. 7 ); copulatory openings (CO) located on the underside of scape near the apex, associated with terminal pockets (TP) ( Fig. 7 ); copulatory ducts (CD) long ( Fig. 7 ); fertilization ducts (FD) short and sinuous ( Fig. 7 ).

Distribution.— Coastal California from San Mateo to Los Angeles Counties.

Habitat.— Troglophilic species with several cave records but also known from coastal scrub under stones and boulders.

Etymology.— The Latin translation of pallidulus means somewhat pale.

Remarks.— There is some confusion about the male specimen collected by J. C. Chamberlin in Santa Clara County. The locality information found on the label is different than the information found in the original paper by Chamberlin & Ivie (1943). The label mentions “Stanford, 122.37 nw.” whereas in the published paper, “Santa Cruz (W 122°: N 37°)” is written. Since the published paper and the coordinates point to Santa Cruz, we assume that a mistake occurred on the label.

Figures

FIGURE 25. Distribution map of Oaphantes pallidulus (Banks 1904), O. cryophilus n. sp. and O. prometheus n. sp.

FIGURES 1–8. Oaphantes pallidulus. 1, endite and chelicera of male, lateral view (arrow points to setose tubercle); 2, face of male, frontal view (arrow points to mastidion); 3, male palp, retrolateral view (arrow points to paracymbial keel); 4, male palp, prolateral view (arrow points to embolus spike): 5, embolic division of male palp, prolateral view; 6, epigynum, ventral view; 7, internal genitalia, dorsal view; 8, epigynum of female, lateral view. Scale bars for figures 1–4, 6–8 = 0.5mm, figure 5 = 0.1 mm.

FIGURES 9–16. Oaphantes cryophilus. 9, endite and chelicera of male, lateral view (arrow points to setose tubercle); 10, face of male, frontal view (arrow points to mastidion); 11, male palp, retrolateral view; 12, male palp, prolateral view (arrow points to embolus dentation); 13, embolic division of male palp, prolateral view; 14, epigynum, ventral view; 15, internal genitalia, dorsal view, 16, epigynum of female, lateral view. Scale bars for figures 9–10, 14–16 = 0.5mm; figures 11–13 = 0.1 mm.