Sesieutes Simon
Creators: name: Deeleman-Reinhold, Christa
Publisher: name: Zenodo
Year: 2001
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Liocranidae
Sesieutes

description: Genus <i>Sesieutes</i> Simon <i>Sesieutes</i> Simon, 1897 HNA: 153. Type species: <i>Sesieutes</i> lucens Simon, 1896b, &amp;male;, Singapore. <i>Described species</i>.— <i>Sesieutes</i> lucens Simon, 1896b, &amp;male; Singapore; <i>S. scrobiculatus</i> sp. <i>n</i>., &amp;male;&amp;female;, N Sumatra, this volume; <i>S.</i> nitens sp. <i>n</i>., &amp;male;&amp;female;, W Sumatra, this volume; <i>S. borneensis</i> sp. <i>n</i>., &amp;male;&amp;female;, C and N Borneo, this volume; <i>S. bulbosas</i> sp. <i>n</i>., &amp;male;&amp;female;, wide coastal zone of E Borneo, this volume; <i>S. minor</i> sp. <i>n</i>., &amp;male;&amp;female;, N Borneo, this volume; <i>S. emancipatus</i> sp. <i>n</i>., &amp;male;&amp;female;, Malaysia, Perak, Chenderiang, this volume; <i>S. schwendingeri</i> sp. <i>n</i>., &amp;male;&amp;female;, N Thailand; <i>S. erawan</i> sp. <i>n</i>., &amp;male;, W Thailand, this volume. <i>Unidentified specimens</i> (map 38): Loe. 1: propeS. <i>emancipatus,</i> Malaysia, Maxwell Hill, 1 &amp;male;, 1 &amp;female;(MHNG). Loc. 2: W Sarawak, Matang 2 &amp;female;: carapace almost smooth. Loc. 3: prope <i>S. borneensis</i>, Brunei, 2&amp;female; (B.734 and B.648). Loc. a (not on map): Thailand, Nam Tok Phliu, Khao Sabap National Park, 1 <i>&amp;male;</i>, 1&amp;female; (MHNG). Loc. b (not on map): N Thailand, Doi Chang, 1930 m, Huay Nam Dang National Park, 1 &amp;female; (MHNG). <i>Old material studied</i>.— Holotype &amp;male; of <i>Sesieutes</i> lucens Simon, Singapore (MNHNP 13529). <i>Diagnosis</i>.— Reddish or chestnut to dark, armoured spiders, with dorsal scutum in males, ventrally there is an epigastric scutum only. Spiders in this genus can be distinguished from other phrurolithines by the oval carapace with rebordered clypeal lobe (fig. 744). It is separated from other genera except <i>Teutamus</i> and Plynnon by the narrow, more or less wedge-shaped posterior border of the carapace. The male palpal tibia has a broad proximal and sometimes a thinner distal retrolateral apophysis; the embolus lies in an apical coil, in some species hidden behind the tegulum, the tip is aligned with a lanceolate conductor and often there is a transparent lanceolate median apophysis. The epigyne is a flat plate with paired or unpaired rimmed openings which lead through wide sclerotized insemination ducts into the spermathecae; no bursae are apparent. <i>Description.</i> — Head with parallel sides, in front a rebordered clypeal lobe; seen from side head region slightly higher than thorax, in posterior third gently sloping down towards rear. Thoracic groove obsolete, in the species from northern Thailand replaced by a deep round pit. Both eye rows parallel, straight, PER slightly wider than AER, PME often smaller than other eyes and lacking pigment ring, sometimes oval. Clypeus 1 d AME. Labium as long as wide. Chelicerae with conspicuous condyle, 3-4 promarginal and 1-2 small widely spaced retromarginal teeth, anterior surface convex, without spine. Sternum smooth and shiny with faint radiating grooves, posteriorly rounded between coxae IV, pedicel not covered by carapace, in males fused with sternum except in the species from N Thailand. Intercoxal triangles with pit. Retrocoxal window absent. Femora basally dilated, dorsally geniculate, first pair with 1-3 prolateral distal spines, femora II-III spineless, anterior tibiae and metatarsi not flattened ventrally, with a single or double row of ventral spines; posterior tibiae and metatarsi with fewer and smaller spines, posterior metatarsi with apical brush. Tarsal claws with 3-8 teeth. Abdomen with transversely grooved collar. Both sexes with dorsal scutum, largest in males, smaller in females, and ventrally a large undivided epigastric scutum, dorsal scutum absent in <i>schwendingerr,</i> postgenital scutum absent in both sexes. Ventral scutum surrounding lung slit. Spinnerets in females as in fig. 743 and as in <i>Jacaena,</i> figs 782-783, 793, ALS tapering, separated, PMS in females laterally compressed, sometimes boot-shaped (fig. 743) anteriorly (ventrally), with 2 rows of elongate atypical cylindrical gland spigots (of reduced size in 5. <i>emancipatus),</i> PLS in both sexes with short rounded distal segment. Male palpal tibia most often with proximal and distal retrolateral apophysis, the proximal often with apical membranous portion; tegulum distally with short wide crescent sperm duct, leading to partly hidden filiform coiled embolus on hind (dorsal) side of bulb, tip of embolus aligned with spiniform articulating conductor. The depressed area in which lie the female copulatory openings is often covered with black substance. Map 37: ■ Plynnon zborowskii ▲ <i>P</i> longitarse ◙ <i>P. jaegeri</i> Ө Unidentified specim en 1-6. <i>Variability</i>.— Two male specimens were observed with a malformation in the palp. One of the males of <i>S. bulbosus</i> from Danum Valley has the distal tibial apophysis shortened and lacking the distal “hook”; one of the males of <i>S. minor</i> has the distal appendages of the tegulum deformed. <i>Habitat</i>.— Typical ground-dwelling spiders. Collected by sifting leaf litter or in ground traps. In lowland and in mountains, primary and semi-primary forests, but occasionally also light secondary forest (Thailand, E Kalimantan). Sometimes two syntopic species together (Kinabalu, Matang, Brunei). <i>Distribution.</i> — Southern Thailand, Myanmar (Burma), Malay Peninsula, Sumatra, Java and Borneo. <i>Taxonomic remark.</i> — The new species <i>S. scrobiculatus</i>, <i>S. nitens, S. borneensis</i> and <i>S. bulbosus,</i> distributed over the Malay Peninsula, Sumatra and Borneo, are closely related to <i>Sesieutes</i> lucens. They all share the large AM eyes. They have similar palps with a characteristic double tibial apophysis, the distalmost branch is thin and peters out along the lateral cymbial margin. It differ in length, thickness and curvature among the species. The proximal branch varies somewhat, it <i>is</i> thick and rounded, lobed or angular. The epigynes in this group are much more diverse, with epigynal openings located anteriorly or laterally. Differences in epigyne in the females found together with these males are quite clear: they differ in position of opening in relation to other elements; also the extent and position of internal coils, size, shape and position of spermathecae are widely different (figs 743, 748, 752, 756). Another property in which species differ is the sculpture of the carapace. The species living in Thailand are less homogenous then those in the Malay archipelago.
description: Published as part of <i>Deeleman-Reinhold, Christa, 2001, Forest Spiders of South East Asia With a revision of the sac and ground spiders (Araneae: Clubionidae, Corinnidae, Liocranidae, Gnaphosidae, Prodidomidae and Trochanteriidae)., pp. 400-505 in Forest Spiders of South East Asia With a revision of the sac and ground spiders- Family Liocranidae, Leiden, Netherlands :Brill Leiden; Boston; Köln</i> on pages 446-448, DOI: 10.5281/zenodo.814704