Caracladus tsurusakii Saito, 1988

Frick, Holger & Muff, Patrick, 2009, Revision of the genus Caracladus with the description of Caracladus zamoniensis spec. nov. (Araneae, Linyphiidae, Erigoninae), Zootaxa 1982, pp. 1-37 : 18

Caracladus tsurusakii Saito, 1988

( Figs 40–46 )

Caracladus tsurusakii Saito, 1988: 21 , figs 11–15.

Type material. HOLOTYPE: Japan: Hokkaido: Kuttyuan-cho, Abuta-gun, Youtei-zan mountain [42°52'30'' N, 140°39'30'' E], 1♂ 25.ix.1981, leg. N. Tsurusaki, S. Nakano, S. Sasaki ( NSMT Ar5249 , examined) ( Saito 1988). PARATYPES: Japan: Hokkaido: Kuttyuan-cho, Abuta-gun, Youtei-zan mountain [42°52'30'' N, 140°39'30'' E], 1♀ 25.ix.1981, leg. N. Tsurusaki, S. Nakano, S. Sasaki ( NSMT Ar5250, examined) ( Saito 1988); Kuttyuan-cho, Abuta-gun, Youtei-zan mountain [42°52'30'' N, 140°39'30'' E], 1♂ 25.ix.1981, leg. N. Tsurusaki, S. Nakano, S. Sasaki ( Saito 1988) .

Diagnosis. Males: Most similar to C. avicula with differences in the structure of the male palp ( Saito 1988). Cephalic lobe similar to C. avicula but more robust and lacking a neck. Embolus whip-like as in C. avicula but much longer and with a loop back, radical tailpiece long and bent ( Fig. 41 ). Distal suprategular apophysis blunt and nearly transparent ( Fig. 41 ). Palpal tibia with two well defined apophyses ( Fig. 42 ).

Females: Nearly triangular dorsal plate with two copulatory pouches anterior and ventral to it and together not broader than the anterior end of the dorsal plate ( Fig. 40 ).

Description. Male (holotype, NSMT Ar5249): Total length: 2.50 mm. Cephalothorax: chestnut brown with darker radiating lines, cervical grooves black ( Saito 1988); 1.03 mm long without cephalic lobe ( Fig. 45 ), 1.35 mm long with cephalic lobe ( Fig. 45 ); 0.78 mm wide. Cephalic lobe: projecting forward, thick at base and sharply pointed tip with sparse stout hairs; at thinnest part below the eye-field 0.14 mm wide laterally, 0.23 mm wide dorsally ( Figs 43, 45 ); sulcus absent ( Fig. 44 ). Eyes: PME upmost on the cephalic lobe, separated by slightly less than 1.5 times their diameter; position of the PLE adjacent to and above the ALE; one long macroseta projecting forward between AME ( Fig. 45 ); anterior row slightly procurved, eyes separated by their radius. Clypeus: wide, slightly convex. Chelicerae: dark brown ( Saito 1988); promargin with five teeth; retromargin with six denticles; many broad stridulatory striae. Sternum: yellowish brown, strongly darker at the margins ( Saito 1988). Legs: tibia I–IV with one dorsal proximal macroseta (1-1-1-1); Tm I: 0.63. Pedipalp: prolateral tibial apophysis glabrous, facing forward; retrolateral tibial apophysis hairy, facing forward ( Saito 1988: Fig. 12 ); suprategular apophysis semi circular; marginal suprategular apophysis minute; distal suprategular apophysis thin, blunt ( Fig. 41 ); embolic membrane with papillae; radix simple without any processes other than the long radical tailpiece and the very long, whip-like embolus that is strongly curved towards the tip ( Fig. 41 ).

Female (paratype, NSMT Ar5250): Total length: 2.58 mm. Cephalothorax: 1.08 mm long; 0.83 mm wide; general appearance similar to males, but without cephalic lobe ( Saito 1988). Eyes: anterior row slightly recurved, separated by about the radius of the AME; posterior eyes separated by at least an eye diameter ( Saito 1988). Epigyne: dorsal plate visible in ventral view; receptacula lateral to the dorsal plate, barely visible in transparency trough ventral plate ( Fig. 40 ); very small copulatory pouches ( Fig. 40 ). Vulva: without copulatory duct ( Fig. 40 ); receptacula globular.

Distribution. Only known from the type locality on Hokkaido, Japan ( Saito 1988).

Habitat. The specimens were collected under leaf litter by sifting or with pitfall traps ( Saito 1988). If we correctly located the locus typicus, this species occurs on a volcano on ca. 1300 m a.s.l.

Phenology. One record from late September, only.

Remarks. C. tsurusakii lacks a copulatory duct. The insertion of sperm is assumed to take place through a space between the ventral and the dorsal plates which are supposed to be pressed apart during copulation.

Figures

FIGURES 40 – 46. Caracladus tsurusakii Saito, 1988. Female: epigyne ventral (40). Male: palp prolateral (41); palpal tibia dorsal (42); cephalothorax dorsal (43), frontal (44) and lateral (45); right leg tibia I retrolateral (46). Scale: 200 Μm. Specimens: Paratype, NSMT Ar 5250 (female); holotype, NSMT Ar 5250 (male).

FIGURES 9 – 16. Caracladus avicula (L. Koch, 1869). Male: cephalothorax lateral (9), frontal (10), cephalic lobe lateral (11); thick hair on cephalic lobe anterior to the PME (12); chelicerae lateral (13); sulci frontal (14); booklung cover ventral (15); left spinnerets (16). Scale: 100 Μm if not stated differently.