Trilacuna werni Eichenberger

Eichenberger, Beata & Kranz-Baltensperger, Yvonne, 2011, New Trilacuna species from Thailand, Malaysia and Sumatra (Araneae, Oonopidae), Zootaxa 2823, pp. 1-31 : 14

Trilacuna werni Eichenberger n. sp.

( Figs. 10–12 )

Type material: Holotype male ( PBI_OON 00015959 ): Thailand: Chiang Mai Province: Chomthong District, Doi Inthanon N.P ., cloud forest at 2000 m, 15. November 1976, leg. P. Lehtinen, deposited in ZMUT. Male paratype ( PBI_OON 00031977 ), collected with holotype, deposited in ZMUT.

Etymology: The species epithet refers to the first name of Werner Graber (nickname Werni ) who is currently working at the Anatomical Institute of Bern, Switzerland, in the Department of Topographic Anatomy and Neuroanatomy.

Diagnosis: This species can be distinguished from all other Trilacuna species by the male bulbus which has a conspicuous ventral groove with a long row of short, slender lobes (grl) (figs. 12. E–G); the finely striated retrolateral-basal surface of femur IV (fig. 11. D); and the dorsal abdominal scutum which is anteriorly fused with the ventral scutum (fig. 11. C).

Description: Description based on 2 males (plus 1 male for SEM).

MALE: Body length 2.2 mm, proportion carapace length:abdominal length 1:1.13. Uniformly orange-brown species (figs. 10. A–C).

Carapace (figs. 10. E, G) ovoid, slightly elevated, surface granular, cephalic part additionally transversally striated, without spikes, lateral margin straight, with blunt denticles, with second, strongly rebordered, straight margin below. Eyes posterior row straight from above, procurved from front. Sternum (figs. 10. D, F) with radial, wrinkled furrows between coxae, surface coarsely reticulate in the middle, anterior margin with transverse groove; setae sparse, light, needle-like, evenly scattered. Mouthparts: Chelicerae promargin with row of flattened setae (fsh) in combination with feather-like setae (flh), (see fig. 2. E); labium rectangular, not fused to sternum, anterior margin deeply incised (ldi); endites slender, distally only slightly branched (fig. 11. B), distal inner margin with patch of fork-like serrated setae (see fig. 2. F).

Abdomen: Ovoid, postepigastric scutum long, semicircular, with short posteriorly directed lateral apodemes, posterior spiracles connected by groove (fig. 11. G).

Legs: Special hairs on ventral apex of tibiae III and IV not observed. Metatarsi III, IV and tarsus IV with harpoon-like hairs (see fig. 2. G). Femora III and IV with ventral hump, with distal patch of small elevated and incised structures (figs. 11. E–F). Femora without spines.

Male genitalia: Epigastric region (fig. 11. G) with small hole (slh) anterior of groove connecting the posterior spiracles, framed by lateral, needle-like hairs directed to center; with strongly sclerotized, curved arches posterior to the anterior spiracles. Male palp (figs. 12. A–J) embolus-conductor-complex complicated, divided into two conspicuous branches with a retrolateral, mesally curved embolic part and a prolateral conductor-complex. Embolus (emb) short, slender, lamellar, mesially curved, framed by a palm leaf-like branch (plb) with a broadish flat stem with lateral, thick setae (figs. 12. E–J). Ventral conductor with a smooth, distally widened, flat branch (wfb) surrounded by numerous setae of different size (figs. 12. E–I). Bulb about twice as long as cymbium, stout, tapering apically (figs. 12. A–B). Femur elongated, slightly enlarged (figs. 12. A–B).

FEMALE: unknown.

Distribution: Known only from type locality, the Doi Inthanon (the highest mountain of the country) in northern Thailand.

Figures

FIGURE 10: Trilacuna werni n. sp. Male: A. habitus dorsal view; B. habitus ventral view; C. habitus lateral view; D. sternum ventral view; E. carapace dorsal view; F. sternum ventral view, SEM; G. carapace dorsal view, SEM; H. carapace anterior view. Abbreviations: boc, booklung covers. Scale bars: A – C 1 mm; D – H 0.5 mm.

FIGURE 11: Trilacuna werni n. sp. Male: A. endites ventral view; B. endites ventral view, SEM; C. abdomen anterior view; D. femur IV prolateral view, proximal part, SEM; E – F. femur IV ventral view, distal part; G. gonopore ventral view. Abbreviations: slh, small hole; sa, sclerotized arch. Scale bars: A – C 0.5 mm; D, G 300 Μm; E 100 Μm; F 50 Μm.

FIGURE 12: Trilacuna werni n. sp. Male: A – B. left palp, prolateral view; C. right palp, prolateral view, SEM; D. left palp, dorsal view, SEM; E – F. left embolus-conductor-complex, prolateral view; E – F. left palp, embolus-conductor-complex, prolateral view; G. left palp, embolus-conductor-complex, ventral view, SEM; H. left palp, embolous-conductor-complex, dorsal view; I. left embolusconductor-complex, dorsal view; J. embolus, dorsal view, SEM. Abbreviations: emb, embolus; plb, palm leaf-like branch; wfb, distally widened flat branch; grl, groove with row of lobes. Scale bars: A – B 300 Μm; C – D 100 Μm; E – I 50 Μm; J 5 Μm.