Mysmena quebecana Lopardo & Dupérré, 2008

Lopardo, Lara, Dupérré, Nadine & Paquin, Pierre, 2008, Expanding horizons ... The first report of the genus Mysmena (Araneae, Mysmenidae) from continental North America, with the description of a new species, Zootaxa 1718, pp. 36-44 : 37-43

Mysmena quebecana Lopardo & Dupérré new species

( Figs 1–18 )

Types. Male HOLOTYPE from Canada, Québec, Parc National de la Yamaska, 45.43860ºN; 72.60721ºW, 18–25.vii.2006, water pan, maple forest, col. A. Mochon et al.; female paratype from the same locality, 45.43680ºN; 72.60472ºW 01–08.viii.2006, pitfall, open field, col. A. Mochon et al., deposited in Museum of Comparative Zoology at Harvard (MCZ).

Etymology. The species epithet is derived from Québec, the province of Canada in which the collections were made.

Note. The male and female of this new species are tentatively paired, as both sexes were collected in the same locality, but not together.

Diagnosis. Mysmena quebecana new species can be distinguished from other Mysmena species by the following combination of features: a small posterior bump on the globose abdomen in both male and female ( Fig. 2 ); carapace height similar in both sexes ( Fig. 1 ); male with sclerotized spot on femur I, female femoral spot on femora I and II; a wide posterior respiratory spiracle; female with scapus and coiled spermathecae ( Figs. 4–6 ); male palp with relatively short, curved embolus ( Figs. 3 , 10 ), and cymbial process ( Figs. 3 , 8, 9, 11 ). Mysmena quebecana new species is the only described species of Mysmena occurring in continental North America. The male palp of M. quebecana new species resembles that of M. leucoplagiata (Simon 1879) , M. guianensis Levi 1956 , M. tasmaniae Hickman 1979 , and M. gibbosa Snazell 1986 , but can be distinguished from these species by the shorter, curved (but not coiled), and thicker embolus, and by shape of the bulbal shield and the orientation of the shield conductor ( Fig. 10 ). The female genitalia of M. quebecana new species resembles that of M. gibbosa , and M. leucoplagiata , but it can be distinguished from these species by the presence of more defined copulatory ducts (instead of wide irregular and extremely membranous ducts, where no trajectory can be distinguished), and less coiled spermathecae, respectively ( Figs. 4–6 ).

Description. MALE (Holotype): Carapace not elevated, as in female, length 0.31, width 0.28, height 0.19. Leg measurements (legs I and IV only; fe/pa/ti/mt/ta): I 0.28/0.12/0.19/0.16/0.17; IV 0.22/0.09/0.14/0.12/ 0.14. Femoral spot on leg I, almost indistinguishable. One prolateral clasping spine at base of distal third of metatarsus I ( Figs. 12, 14 ). Chelicerae not fused. Clypeus height approximately 1.5 AME diameters. Sternum shield-like, domed, length 0.35, width 0.33, length/width 1.06, posterior border truncated, about width of two coxae IV. Abdomen globose, with small bump posteriorly, length 0.53, width 0.47, height 0.51. Macrosetae: Macrosetae long, slender, one distal macroseta on dorsal patellae, one basal on dorsal tibiae. Distal half of tarsus I with row of prolateral, short, slender, distinct setae truncated at apex ( Figs. 14 , 17, 18 ). Tarsal organ located basally, capsulate, domed, with rounded orifice ( Fig. 13 ). Three tarsal claws, serrate accessory setae (false claws) present ( Fig. 15 ). Median tarsal claw on leg IV elongate, sinuous ( Fig. 16 ). Trichobothrial bases simple, smooth, proximal hood smooth, similar on all legs and segments. Tarsal trichobothria absent. Trichobothria (legs I and IV only): I, tibia 2-1-0; metatarsus 1-0. IV, tibia p1-2-1-0; metatarsal trichobothria absent. Appendage cuticle squamate. Color: Carapace yellowish, ocular area darker, lateral borders black; sternum yellowish with two dark longitudinal bands. Mouthparts yellowish. Legs yellowish, distal patellae, tibiae and metatarsi darker. Abdomen dark with four white spots, visible in posterior view, forming inverted trapezium; white ventral band surrounding spinnerets. Eyes: Eight eyes subequal. AME black, other eyes pearly white. Lateral eyes contiguous, PME separated ~one diameter, AME separated ~1.75 their diameter. Respiratory system: Anterior spiracles connected to epigastric furrow. Posterior respiratory system with two distant spiracular openings exteriorly connected by thin ridge (i.e., one wide spiracular opening). Internal respiratory conformation not observed. Spinnerets: Spinneret field located ventrally on abdomen (as in Fig. 2 ). Colulus large, fleshy, triangular, about half length and width of ALS. Six spinnerets (spigot conformation not observed). Palp and copulatory bulb ( Figs. 3 , 7–11 ): Tibia cup-shaped, without apophyses or trichobothria, ventral border slightly projected over cymbium ( Fig. 8 ), tibial rim with aligned setae, except prolaterally.

Cymbium oriented ventrally on palp, so that bulb and embolus face dorsally (i.e. frontally in resting position). Because the ventral mysmenid cymbium seems to be apomorphic compared to most araneoids, cymbial structures are here described relative to it rather than the pedipalp as a whole. Cymbium modified apically, with pointed tip. Two apical furrows functioning as cymbial conductors (CyC) on internal cymbium, associated to embolus, running parallel to each other. Retrolateral cymbial conductor (CyCr) with short row of small setae on ventral edge. Prolateral cymbial conductor (CyCp) longer, on prolateral apical margin of cymbium. Cymbial groove (CyG) short, originating distally and retrolaterally on cymbial margin between paracymbium (PC) and retrolateral cymbial conductor, running diagonally on cymbial dorsal surface. Cymbial groove with apical flap. Small pointed cymbial process (CyP) located dorsally, at end of cymbial groove. Paracymbium large, flat, medially located, with setae. Bulbal shield (BS, membranous expansion of tegulum, relative to embolus) present, not covering embolus, but with embolic depression functioning as conductor (BSC) oriented diagonally toward cymbial conductors. Bulbal conductor and median apophysis absent. Exposed part of embolus relatively short (almost as long as palpal length), curved clockwise (left palp) but not coiled, resting on shield conductor. Membranous expansion of basal exposed embolus (pars pendula) containing spermatic duct. Spermatic duct enters embolus at distal end.

FEMALE (Paratype): As in male ( Figs. 1, 2 ), except as noted (features at SEM level not observed). Carapace length 0.55, width 0.45, height 0.25. Femoral spot on legs I and II. Prolateral clasping spine absent. Sternum length 0.32, width 0.35, length/width 0.91, as in male. Color: as in male, darker areas more spotted, maxillae basally darker. Epigynum ( Figs. 4–6 ): Epigynal area not sclerotized, with membranous scapus. Copulatory openings not visible. Copulatory ducts (CD) distinct, extremely membranous, coiled, seeming to open from common membranous internal atrium. Spermathecae (S) sclerotized, elongated, containing coiled duct distally expanded into a sort of reservoir. Fertilization ducts (FD) not clearly distinguishable, seemingly membranous.

Natural history. The specimens were collected in pitfall traps and water pans in two very different habitats: a mature maple forest and an open field. The low number of specimens does not allow inferring ecological affinities other than its occurrence in the Sugar maple-basswood domain of the Appalachian Lowlands.

Distribution. Known from Québec, Canada.

Other material examined. Only known from type material.

Figures

FIGURES 1 – 5. Mysmena quebecana new species. 1 – 2. Female (paratype), lateral view. 1. carapace; 2. abdomen. 3. Male (holotype), cleared left palp, tibia and patella, retrolateral view. 4 – 5. Female (paratype), cleared epigynum, drawings. 4. ventral view; 5. dorsal view. Scale bars: 1 – 3 = 0.1 mm; 4 – 5 = 0.05 mm.

FIGURE 6. Mysmena quebecana new species. Female (paratype), cleared epigynum, slide preparation, ventral view. Scale bar: 0.05 mm.

FIGURES 7 – 11. Mysmena quebecana new species. Male (holotype), right palp and tibia (inverted). 7. Prolateral-dorsal view; 8. Prolateral view; 9. Retrolateral-ventral view; 10. Male palp, dorsal view; 11. Detail of palpal tip, retrolateral view.

FIGURES 12 – 16. Mysmena quebecana new species. Male (holotype), right legs. 12 – 15. Right leg I. 12. Metatarsus, prolateral view, note single clasping spine; 13. Tarsus-metatarsus joint, dorsal view, note tarsal organ; 14. Tarsus and metatarsus, dorsal view, note metatarsal clasping spine and tarsal distal row of small setae on prolateral side; 15. Tarsal claws. 16. Right leg IV, tarsal claws, retrolateral view, note sinuous and slender median claw.

FIGURES 17 – 18. Mysmena quebecana new species. Male (holotype), right leg I. 17. Tarsus, prolateral view, arrows to prolateral row of short modified setae on distal half; 18. Same, detail of distal tarsus.