Liphistius tioman Platnick & Sedgwick 1984
Creators: name: Peter J. Schwendinger
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Liphistiidae
Liphistius
Liphistius tioman

description: Liphistius tioman Platnick & Sedgwick, 1984
Figs 11-12
Liphistius tioman Platnick & Sedgwick, 1984: 28 -29, figs 81-
87 (description of male and female).
Type material: AMHN; male holotype and female paratype (not examined); Malaysia, Pahang, Tioman Island, Gua Sinah and Gua Panah, 2600 ft. altitude; 29.VII.1982; leg. W.C. Sedgwick.
Material examined: MHNG, sample SIM-01/09; 1 male (matured 3.I.2002), 7 females (moulted 17.XII.2001; 2.IX.2001, 6.III., 4.X.2002, 7.VI.2003; 8.IX.2001, 16.II., 23.VI.2002), 1 penultimate male;
Pahang, Tioman Island, Gunung Kajang (2°45’45’’N, 104°08’43’’E), 820-850 m; 30.VI.2001; leg. P.J. Schwendinger.
Diagnosis: Males distinguished from those of all other Liphistius species by a deeply and widely divided retrolateral apophysis on palpal tibia, both parts being equally long (Fig. 11A, H-I). Males distinguished from those of other species in the tioman -group additionally by a long and pointed para-embolic plate (Fig. 11 C-E) and by a very narrow tegulum with few denticles on proximal edge, situated very close to dorsal apex of contrategulum (Fig. 11B, F). Females with poreplate widely fused with posterior stalk; receptacular cluster medially more or less distinctly divided; CDO undivided (Fig. 12).
Additions to description of male: Scopula: In distal two-thirds of ventral side of tarsus I, in distal threequarters of tarsus II, in distal two-thirds of tarsus III, in distal half of tarsus IV (narrower than on other tarsi). All scopulae thin and only distally (behind the claws) divided by a glabrous longitudinal median stripe.
Palp: Tibial apophysis situated apically, not set back from anterior margin of palp (Fig. 11G), deeply divided: retrolateral part deeper, aligned with axis of tibia and carrying three very short pointed megaspines; retrodorsal part much narrower, pointing away from axis of tibia, carrying a single, slightly longer pointed magaspine (Fig. 11A, G-I). Distal margin of cymbium with very indistinct lobes (Fig. 11C). Paracymbium relatively short and moderately deep (Fig. 11A); cumulus indistinct, carrying a fairly compact group of long stiff bristles (Fig. 11A). Subtegulum without apophysis. Tegulum very narrow, its proximal edge carrying few overlapping scale-like denticles, situated close to dorsal apex of contrategulum (Fig. 11B, F). Contrategulum with large, conical ventral process being slightly constricted at base (Fig. 11F); distal edge of contrategulum distinctly elevated and composed of numerous parallel ribs instead of teeth (Fig. 11 B-F), dorsal apex relatively small and narrowly rounded, only slighly elevated above underlying surface (Fig. 11B, F). Para-embolic plate long, narrow and asymmetrically triangular (Fig. 11 B-E); embolus proper strongly inclined prolaterad (Fig. 11B), distally widened; dorsal wall of sclerotised part distinctly wider than ventral wall, ending in a quadrangular lobe (Fig. 11 B-C, F), retrolateral wall not enforced by ridges but only with an indistinct, short distal keel (Fig. 11B, F); membranous part of embolus proper slightly widened distally (Fig. 11C).
Additions to description of female: Genital atrium of vulval plate (Fig. 12) without median hairs, few to several lateral hairs present in some females; lateral margin of genital atrium not forming flaps bending ventrad and inwards (as usual in Liphistius) but only indistinct mounds on the dorsal (not the ventral) side (Fig. 12A, C, F). Posterior stalk relatively short and wide, fused with poreplate without recognizable transition, reaching lateral margins of vulval plate in some females. Poreplate of variable shape, in most females examined anteriorly slightly narrower than posteriorly, its anterior margin indistinctly invaginated, without lobes; CDO quite large, undivided, anteriorly deep, posteriorly level with rest of poreplate (Fig. 12A, C, F; but see illustration of paratype in Platnick & Sedgwick, 1984: fig. 86); receptacular cluster quite large and wide, more or less distinctly divided into two paramedian subclusters (Fig. 12B, D-E, G).
Taxonomic remarks: The tibial apophysis of the male palp of L. tioman is unique and distinctly autapomorhic. A similar divided tibial apophysis is found in males of the linang -group, but that is considered to have evolved convergently (see also Discussion). The wide ventral process of the contrategulum, the wide posterior stalk and the divided receptacular cluster indicate a close relationship with L. panching and L. negara sp. nov.
Variation: Carapace lengths in males (n=2; values of the holotype are taken from Platnick & Sedgwick, 1984: 29) 6.23-6.93, carapace widths 6.01-6.34. In females with fully developed copulatory organs (n=7) the carapace length is 5.54-7.92 and the carapace width 5.15-7.38. Variation in the shape of poreplates of the females examined is shown in Fig. 12. The retrolateral tibial apophyses of the left and right palp of the examined male are shown in Fig. 11A and Fig. 11I, respectively.
Distribution: Known only from higher altitudes on Tioman Island (Fig. 1, locality 10).
Biology: Spiders of this species were found under and between huge granite boulders (some of them touching each other and forming recesses) in a lush rain forest. These recesses probably correspond to the Gua Sinah or Gua Panah which is the exact type locality and which were described as not being real caves (like their Malay names suggest) but just overhung caverns (Platnick & Sedgwick, 1984: 29). Burrows were mostly dug into loamy soil at the base and between the bolders (a few small spiders had silken nests on the surface of bolders just above the ground, as described for juvenile spiders of L. trang, see Schwendinger, 1987: fig. 5), and they had up to eight exceptionally long (up to 34 cm) signal lines spread over soil or rock surface. The trapdoor of the adult male (before its final moult) was 1.8 cm long and 3.2 cm wide, that of the largest female was 1.9 cm and 3.2 cm, respectively. When collected at the end of June, four females had egg cases: one was not opened, another was empty, the remaining two were 2.2-2.7 cm long, 2.8-2.9 cm wide and 1.9 cm high; they contained 3rd instar spiderlings (not collected, not counted).
description: Published as part of Peter J. Schwendinger, 2017, A revision of the trapdoor spider genus Liphistius (Mesothelae: Liphistiidae) in peninsular Malaysia; part 1, pp. 391-445 in Revue suisse de Zoologie 124 (2) on pages 410-411, DOI: 10.5281/zenodo.893555