Systaria Simon, 1897

Dankittipakul, Pakawin & Singtripop, Tippawan, 2011, Seven new species of Systaria Simon, 1897 from Southeast Asia (Araneae, Clubionidae, Systariinae), Zootaxa 2905, pp. 16-32 : 18-19

Systaria Simon, 1897

Systaria Simon, 1897a: 87 . Lehtinen 1967: 237; Deeleman-Reinhold 2001: 202. Hebrithele Berland, 1938: 137 (synonymised by Deeleman-Reinhold 2001: 202). Type species by original designation: S. drassiformis Simon, 1897 .

Diagnosis. Representatives of Systaria can be distinguished from all other Asian Systariinae by a combination of characters: the dark and large AME; the widely separated anterior lateral spinnerets; the lengthened distal segment of posterior lateral spinnerets in females; the broad sperm duct running along outer margin of the tegulum; the lack of a median apophysis; the sclerotized bursae located anterior to smaller spermathecae. Members of Systaria can be distinguished from those of Xantharia by the absence of an oblique depression on gnathocoxae, the oval sternum being narrower anteriorly than in the middle, and the tarsi are covered with denser claw tufts. Members of Tamin can be distinguished from those of Systaria by having smaller AME, the sparse claw tuft and the widely separated gnaphosid-like anterior lateral spinnerets are provided with long spigots in males (AME being largest and anterior lateral spinnerets being distinctively shorter in males than in females in Systaria species).

Description. Large to medium-sized clubionid spiders without distinctive coloration pattern. Prosoma oval, longer than wide, widest between coxae II and III, narrowed in front but always more than 2/3 its maximum width; thoracic groove well defined; fovea deep, longitudinal.

AME and PME circular, ALE and PLE oval, AME dark, largest, other pearly white, subequal in size; PER slightly wider than AER, AER recurved, PER slightly procurved; AME separated by less than their radius, less than their diameter apart from ALE; PME separated by twice their diameter, slightly farther from PLE; ALE and PLE separated by almost their diameter. MOQ slightly longer than wide, posteriorly wider than anteriorly; clypeus height at AME, twice their diameter.

Chelicerae long and slender, vertical, with slight lateral condyle; 3 promaginal and 2–3 retromarginal teeth; fang moderately long. Gnathocoxae longer than wide, slightly wider anteriorly, parallel or slightly excavated medially on lateral margins, without oblique depression, slightly divergent, with anterior median scopula. Labium slightly longer than wide, rebordered. Sternum oval, domed, slightly narrower anteriorly than in the middle, with triangular sclerotized extensions to or between coxae.

Leg formula 4123, prograde; trochanters deeply notched; femora with strong spines; patellae short, without spine; anterior tibiae with conspicuous ventral spines; anterior metatarsi with weak ventral spines; metatarsi and tarsi with distoventral scopulae; tarsi with dense claw tuft. Two tarsal claws, dentate.

Opisthosoma ovoid, tapering posteriorly, covered with dense bristles, without dorsal scutum, some species with brownish gray reticulations. Six spinnerets, anterior lateral spinnerets cylindrical, tapering apically, never contiguous, long, widely separated, usually up to one diameter apart, two-segmented, distal segment very short, with one major ampullate and several piriform gland spigots; posterior median spinnerets short, cylindrical in both sexes; posterior lateral spinnerets two-segmented, both segments long, distal segment carrying one large apical and several smaller spigots.

Male palp with femur and patella unmodified; tibia with elevated distoventral hump, and complex retrolateral tibial apophysis. Cymbium with sharply pointed baso-retrolateral cymbial tubercle or oblique basal ridge; invaginated at base on retrolateral side, its surface partially membranous or lightly sclerotized, without pigmentation. Tegulum clearly separated from almost indistinct subtegulum, elongate-oval, protruding posteriorly, strongly excavated meso-prolaterally to accommodate embolus, with broad sperm duct running along its outer margin. Embolic base membranous, originating meso-prolaterally; embolus triangular, gradually tapering toward its apex. Median apophysis absent. Conductor membranous, situated apically.

Epigyne lightly sclerotized, with shallow epigynal atrium and paired copulatory orifices. Atrium often provided with a pair of ridges, presumably to guide and support male copulatory organ towards insemination pore. Copulatory orifices leading to short insemination ducts which closely attached to posterior part of bursae. Bursae sclerotized, situated anteriorly, connected to spermathecae via mostly short ducts. Fertilization ducts variable in shape. After copulation, insemination duct often inflated, forming a spherical ball containing a plug of dark substance ( Figs 14 , 19 , 25 , 31 ); virgin females as in Figs 13 , 37 , 39, 40 .

Taxonomic remarks. The two following characters mentioned are considered synapomorphic and diagnostic for the genus.

A sharply pointed tubercle situated at base on retrolateral side of the cymbium (= cymbial tubercle; Fig. 1 , CT) is found in the males of S. bifida sp. nov., S. decidua sp. nov. and S. acuminata sp. nov. ( Figs 9 , 32 ). In other Systaria species this area is clearly elevated, forming an oblique basal ridge; its coloration is slightly darker than the rest of the cymbium. This modification can be easily observed from a retrolateral view of the male palp ( Figs 10 , 33 ).

The females examined and treated in the present study all share a similar pattern of internal genitalia in which a pair of bursae situated anterior to posterior spermathecae are heavily sclerotized, often with the remaining of numerous gland ductules. Although there is no doubt that the Chinese species belong to Systaria , illustrations of their internal genitalia show a different pattern: the anterior bursae seem to be membranous. Zhang et al. (2009) documented that ‘Bursae situated anterior of copulatory orifices, large sac-shaped and semi -transparent ’. However, it appears to us that most females of Systaria possess sclerotized bursae (see also Deeleman-Reinhold 2001).

It is of interest to note that in Systaria the entrance to the vulva (inseminations ducts) is often plugged, possibly to prevent further matings of the female (Deeleman-Reinhold, pers. comm.). The phenomenon of plugged copulatory organs in female spiders is known in a variety of families, but was not yet recognized and reported for Systariinae.

Natural history. Most of the specimens of Systaria species treated in this study were directly obtained by digging their retreats inside the caves or nearby the cave entrances.

Distribution. Southern China, Southeast Asia including New Guinea.

Figures

FIGURES 9 – 14. Systaria decidua sp. nov., holotype male (9 – 11) and paratype female (12 – 14). 9 – 11 Left male palp (9 ventral, 10 retrolateral, 11 dorsal); 12 – 13 Epigyne, ventral; 14 Vulva, dorsal. Scale lines = 0.1 mm.

FIGURES 15 – 19. Systaria lanna sp. nov., holotype male (15 – 17) and paratype female (18 – 19). 15 – 17 Left male palp (15 ventral, 16 retrolateral, 17 dorsal); 18 Epigyne, ventral; 19 Vulva, dorsal. Scale lines = 0.1 mm.

FIGURES 20 – 25. Systaria bifida sp. nov., holotype male (20 – 23) and paratype female (24 – 25). 20 – 21 Left male palp (20 ventral, 21 retrolateral); 22 – 23 Palpal tibia (22 proventral, 23 dorsal); 24 Epigyne, ventral; 25 Vulva, dorsal. Scale lines = 0.1 mm.

FIGURES 26 – 31. Systaria insolita sp. nov., holotype male (26 – 29) and paratype female (30 – 31). 26 – 27 Left male palp (26 ventral, 27 retrolateral); 28 – 29 Apex of retrolateral tibial apophysis (28 dorsal, 29 prolateral); 30 Epigyne, ventral; 31 Vulva, dorsal. Abbreviations: DP, dorsal process of RTA; VP, ventral process of RTA. Scale lines = 0.1 mm.

FIGURES 32 – 37. Systaria acuminata sp. nov., holotype male (33 – 34), paratype male (35) and paratype female (36 – 37). 32 – 34 Left male palp (32 ventral, 33 retrolateral, 34 dorsal); 35 Palpal tibia, retrolateral; 36 Epigyne, ventral; 37 Vulva, dorsal. Scale lines = 0.1 mm.

FIGURES 38 – 42. Systaria deelemanae sp. nov., holotype female (38 – 40). Systaria scapigera sp. nov., holotype female (41 – 42). 38, 41 Epigyne, ventral; 39, 40, 42 Vulva, dorsal. Scale lines = 0.1 mm.

FIGURES 1 – 3. Schematic drawing of male (1) and female (2 – 3) genitalia of Systaria. 1 Left male palp, ventral. 2 Epigyne, ventral. 3 Internal genitalia, dorsal. Abbreviations: A, epigynal atrium; B, anterior bursa; C, conductor; CC, cymbial concavity; CO, copulatory orifice; CT, cymbial tubercle; E, embolus; FD, fertilization duct; MP, mating plug; RTA, retrolateral tibial apophysis; S, spermatheca; SD, sperm duct; T, tegulum.