Walckenaeria karpinskii (O. Pickard-Cambridge, 1873)

Song, Yanjing & Li, Shuqiang, 2011, Notes on Walckenaeria species (Araneae: Linyphiidae) from China, Revue suisse de Zoologie 118 (1), pp. 175-196 : 187-191

Walckenaeria karpinskii (O. P.- Cambridge, 1873)

Figs 8-10

Erigone karpinskii O. P.- Cambridge, 1873: 447 , pl. 41, fig. 12.

MATERIAL EXAMINED: IZCAS, without registration number; 5♀ 2♂; China, Hebei Province, Zhangjiakou City, Chicheng County, Dahaituo National Nature Reserve (40.90ºN 115.83ºE); collected by Q. Wang, Y. Song and G. Zheng; collected on 5.11.2005 .

DIAGNOSIS: W. karpinskii is similar to W. clavicornis and W. korobeinikovi Esyunin & Efimik, 1996 , but can be distinguished by the shape of the palpal tibia ( Fig. 9C, F ; cf. Esyunin & Efimik, 1996: fig. 4a-f; Millidge, 1983: figs 261-266) and of the dorsal plate of the epigynum ( Fig. 10D, E ; cf. Esyunin & Efimik, 1996: fig. 5a-h).

RE- DESCRIPTION OF MALE (from Dahaituo National Nature Reserve): Total length 2.08. Carapace 0.98 long, 0.71 wide, orange-brown, with a stout horn in ocular area ( Fig. 9A, B ). Clypeus 0.20 high. AME diameter 0.04, ALE 0.07, PME 0.06, PLE 0.07, AME interdistance 0.46 times their diameter, AME-ALE interdistance 0.38 times ALE diameter, PME interdistance 0.50 times their diameter, PME-PLE interdistance 0.55 times PLE diameter. Sternum 0.58 long, 0.53 wide. Coxa IV interdistance 1.08 times their width. Chelicera chestnut-brown, with 4 promarginal and 3 retromarginal teeth ( Fig. 9E ). Tibia of leg I 5.37 times longer than deep. Tm I 0.45, Tm IV present. Number of dorsal spines on tibiae of legs I-IV: 2-2-1-1. Leg measurements: I 2.39 (0.76, 0.28, 0.46, 0.50, 0.23); II 2.38 (0.69, 0.27, 0.58, 0.49, 0.35); III 2.06 (0.57, 0.24, 0.47, 0.44, 0.34); IV 2.79 (0.78, 0.25, 0.72, 0.63, 0.41).

Palp: Patella length half of femur length ( Fig. 9D ). Tibia short, armed with 2 well-developed apophyses; retrolateral apophysis long, slightly curved, decorated interiorly with some unconspicuous teeth ( Fig. 8F, G ); prolateral apophysis biforked, strongly sclerotized, serrated distally ( Fig. 9F ); with 1 prolateral and 2 retrolateral trichobothria. Paracymbium C-shaped, with distal end hooked ( Fig. 8G ). Tegulum distal to subtegulum in unexpanded palp ( Fig. 8F ). Protegulum relatively flat ( Fig. 8F ). Suprategulum ( Fig. 8D ) terminating in strongly sclerotized point, this not visible in unexpanded palp. A suprategular groove visible in unexpanded palp in retrolateral view ( Fig. 8G ). Embolic division: median membrane long and broad, enveloping distal end of long coiled embolus ( Fig. 8B, C, G ); tailpiece relatively short, strongly curved upwards, in prolateral view with a rounded piece extended upwards from anterior margin ( Fig. 8A ); embolus very broad at base, gradually narrowed towards the end, slightly sclerotized along inner margin ( Fig. 8E, G ).

RE- DESCRIPTION OF FEMALE (from Dahaituo National Nature Reserve): Carapace unmodified, similar to that of male in coloration. Total length 2.22. Carapace 1.09 long, 0.77 wide. Clypeus 0.17 high. AME diameter 0.04, ALE 0.07, PME 0.06, PLE 0.07, AME interdistance 0.36 times their diameter, AME-ALE interdistance 0.38 times ALE diameter, PME interdistance 0.60 times their diameter, PME-PLE interdistance 0.47 times PLE diameter. Sternum 0.66 long, 0.55 wide. Coxa IV interdistace 1.07 times their width. Chelicera with 5 promarginal and 5 retromarginal teeth. Tibia of leg I 3.96 times longer than deep. Tm I 0.51, Tm IV present. Number of dorsal spines on tibiae of legs I-IV: 2-2-1-1. Leg measurements: I 2.48 (0.75, 0.29, 0.59, 0.49, 0.35); II 2.36 (0.70, 0.28, 0.55, 0.47, 0.36); III 2.06 (0.61, 0.26, 0.45, 0.43, 0.31); IV 2.78 (0.78, 0.28, 0.73, 0.61, 0.39).

Dorsal plate of epigynum with 2 large linguiform scapes ( Fig. 10A, B ). Copulatory openings present at posterior end of linguiform scapes ( Fig. 10D, E ). Copulatory ducts enclosed in a sclerotized capsule, broad and wavelike at first ( Fig. 10G ), then continuously broadening into a pair of wide extensions with outer margin extended posteriorly (Fig. C, G), narrowing abruptly before entering into globular spermathecae ( Fig. 10F, G ). Fertilization ducts situated mesally ( Fig. 10G ).

VARIATION: 5♀ and 2♂ were measured. Total length varies from 2.08 to 2.15 in males, 2.22 to 2.45 in females. Carapace length is 0.95 to 0.98 in males, 1.09 to 1.11 in females; width 0.69 to 0.71 in males, 0.77 to 0.78 in females. The species shows intraspecific variation in the shape of dorsal plate scape ( Fig. 10A, B ) and the anterior part of the vulva ( Fig. 10D, E ).

DISTRIBUTION: Holarctic. In China it was recorded in the provinces of Hebei and Jilin ( Song et al., 1999).

HABITAT. The spiders were found in the leaf litter of a birch forest and a pine forest.

Figures

FIG. 8 Walckenaeria karpinskii; male from Hebei, China. (A) Distal part of left palp, prolateral view. (B) Embolic division, ventral view. (C) Same, dorsal view. (D) Distal part of suprategulum, ventral view (arrow indicating retrolateral groove). (E) Distal part of embolus (ventral view). (F) Distal part of left palp, ventral view. (G) Same, retrolateral view. Scale lines: 0.1 mm.

FIG. 9 Walckenaeria karpinskii; male from Hebei, China. (A) Eye region, lateral view. (B) Same, frontal view. (C) Tibia of left palp, dorsomesal view. (D) Patella and femur of left palp, retrolateral view. (E) Left chelicera, posterior view. (F) Tibia of left palp, dorsal view. Scale lines: 0.1 mm.

FIG. 10 Walckenaeria karpinskii; two females from Hebei, China. (A, B) Epigyna, ventral view. (C) Vulva, ventral view. (D, E) Epigyna, dorsal view. (F) Vulva, lateral view. (G) Same, dorsal view. Scale lines: 0.1 mm.