Perania selatan, Schwendinger, 2013

Schwendinger, Peter J., 2013, A taxonomic revision of the spider genus Perania Thorell, 1890 (Araneae: Tetrablemmidae: Pacullinae) with the descriptions of eight new species, Revue suisse de Zoologie 120 (4), pp. 585-663 : 651-655

Perania selatan sp. n. Figs 34-35

HOLOTYPE: MHNG, sample Sum-00/27; Ƌ; Indonesia, Sumatra, Lampung Province, Bukit Barisan Selatan National Park, footpath to waterfall, 2 km from road Krui to Liwa , NE of Kubuprahu (5°04’S, 104°03’30”E), 600 m; 5.III.2000; leg. P. J. Schwendinger.

PARATYPES: MHNG, sample Sum-00/27; 7 ♀; same data as for holotype .

ETYMOLOGY: “Selatan” is the Indonesian word for “south”. Noun in apposition.

DIAGNOSIS: Similar to P. deelemanae sp. n., both sexes distinguished by smaller body size and PME interdistance equal to their diameters (distinctly less so in P. deelemanae sp. n.). Male distinguished from those of P. deelemanae sp. n. by shorter, more conical clypeal process; lateral microplates in anterior portion of opisthosoma not quadrangular, several of those in lower rows fused into short straplike lateral plates; conical microplates on anterior side of opisthosoma more distinctly elevated; tip of cymbium narrower; apex of embolus shallower, obliquely truncate, without (or with only very indistinct) subterminal lamella dorsally. Females without clypeal process; common anterior margin of spermatecae with a deeper median invagination; internal chambers of spermathecae with stronger enforcement ribs, usually closer to each other than in P. deelemanae sp. n.

DESCRIPTION OF MALE (holotype): Colour (in alcohol) generally dark brown, carapace, chelicerae, pedipalps, ventral sclerites and dorsal scutum slightly darker, palpal organ and distal articles of posterior legs lighter; membranous parts of opisthosoma grey-brown. Clypeus with short, basally quite narrow conical process FIG. 34

Perania selatan sp. n., male holotype. (A) Carapace, dorsal view. (B) Same, lateral view. (C) Left cymbium, dorsal view. (D) Distal portion of left palp, retrodorsal view. (E) Left palpal organ, distal view. (F) Apex of left embolus, proximal view. (G) Apex of right embolus, proximal view. Scale lines 1.0 mm (A-B), 0.5 mm (C-G).

(Fig. 34A-B). Fovea relatively deep in anterior half. Total length 7.9. Carapace 4.0 long, 2.3 wide; clypeal process 0.4 long, occupying 9% of carapace length. Eye sizes and interdistances: PME 0.24 long, separated by 0.24; ALE 0.22 long; ALE-PLE 0.11; PLE 0.21 long, separated by 1.08. Labium 0.8 long, 1.0 wide. Sternum 2.3 long, 1.7 wide. Chelicerae without modifications; with two teeth on anterior margin of fang furrow.

Palp 3.7 long (1.0+0.5+1.0+1.2). Cymbium with long and exceptionally narrow, acutely pointed apex (Fig. 34C). Palpal organ with long embolus bent from bulbus at almost 180°, fairly straight in proximal portion, sigmoid in distal portion; apex of embolus only slightly deeper than median portion of embolus, obliquely truncate, its upper corner narrowly rounded and protruding far beyond widely rounded lower corner; no subterminal lamella discernible dorsally (Fig. 34D-G).

Legs 3241. Nine (on left side) and twelve (on right side) conical setal bases distributed over almost entire length of metatarsus I prolaterally to ventrally, three (on right side) and four (on left side) over distal quarter of tibia I prolaterally. Paired leg claws with a row of 13-14 teeth on anterior legs, 9-12 on posteriors; unpaired leg claws with one denticle. Leg I 14.8 long (4.4+1.4+4.8+3.0+1.2), leg II 11.5 long (3.2+1.2+3.4+2.6+1.1), leg III 9.2 long (2.7+1.0+2.3+2.2+1.0), leg IV 12.1 long (3.6+1.1+3.3+3.0+1.1).

Opisthosoma 4.4 long, 3.1 wide. Dorsal scutum 3.8 long, 2.8 wide, somewhat oval, posteriorly wider than anteriorly, posterior margin straight, its surface carrying indistinct low tubercles and ridges. Most lateral microplates in anterior portion of opisthosoma medium-sized, elliptical, close to each other and only one row deep in each band; several of those in two lower bands completely fused with each other, forming short lateral strap-like plates (the lowest one longest) and representing remnants of lateral plates; some microplates on and above dorsal margin of pulmonary plate distinctly elevated and pointed; only one broken strap-like horizontal plate on posterior side of opisthosoma. Pulmonary plate 3.2 long, 2.5 wide; genital region flat. Anterior pair of ventrolateral plates largely fused with lateral margin of pulmonary plate, only anterior tips free. Postgenital plate completely fused to pulmonary plate, linked by an indistinct sclerotised suture. Preanal plate 0.2 long, 0.6 wide, with slightly convex anterior margin, straight posterior margin and irregular lateral margins. Anal plate 1.2 long, 1.8 wide.

DESCRIPTION OF FEMALE (“ allotype ”): As in male, except for the following. Total length 7.0. Carapace 3.4 long, 2.3 wide. PME 0.24 long, 0.26 apart; ALE 0.22 long; ALE-PLE 0.06; PLE 0.24 long, 1.10 apart. No clypeal process. Labium 0.7 long, 1.0 wide. Sternum 2.2 long, 1.6 wide. Palp 3.2 long (0.8+0.4+0.7+1.3). Legs 3241; tibiae and metatarsi I-II without conical setal bases. Paired leg claws with 12-14 teeth on anterior legs, 11-12 on posteriors. Leg I 11.4 long (3.4+1.1+3.3+2.4+1.2), leg II 9.6 long (2.9+1.0+2.6+2.1+1.0), leg III 7.9 long (2.3+0.9+1.9+1.9+0.9), leg IV 10.2 long (3.0+1.0+2.7+2.5+1.0).

Opisthosoma 4.4 long, 3.3 wide; several microplates in posterior portion near dorsal scutum slightly elevated and conical, all isolated. Dorsal scutum 3.0 long, 2.0 wide, its posterior margin straight, its surface with distinct tubercles and ridges between them. Anterior plate fragmented into three small plates and several microplates, some of the latter situated in the upper portion (corresponding to dorsal margin of fragmented anterior plate) elevated and pointed but slightly smaller than in males. Pulmonary plate 1.9 long, 2.0 wide; genital region bulged; outlines of light spermathecae clearly visible under cuticle; posterior margin widely rounded. Preanal plate completely fragmented. Anal plate 1.4 long, 1.9 wide.

Vulva (of paratype) relatively short; anterior collar short, its widely rounded anterior margin only little surpassing common anterior margin of spermathecae with a distinct median invagination (Fig. 35A); anterior and lateral sides of spermathecae bulged, without trenches (Fig. 35C); porepatches extending far onto dorsal side of spermathecae (Fig. 35A); ventral side of spermathecae with a paramedian pair of somewhat eliptical chambers with thick walls and strong transversal enforcement ribs; both chambers prominent and in contact with each other (Fig. 35B); ventral side of spermathecae between porepatches and internal chambers unpigmented; ventral wall of genital atrium with pigmented median zone clearly outlined, laterally biconcave (Fig. 35A-B).

VARIATION: Carapace length in seven females ranges 3.4-3.8, carapace width 2.3-2.5. The three larger central fragments of the anterior opisthosomal plate of females are variable in size: largest in the “ allotype ” and in another specimen, smaller in the remaining females. Variation in the shape of the embolus of the left and right palp of the holotype is shown in Fig. 34E-G, variation in the shape of the vulva of three females in Fig. 35B, E-D.

FIG. 35

Perania selatan sp. n., females; first paratype (A-C), second paratype (D), “ allotype ” (E). (A) Vulva dorsal view. (B, D-E) Same, ventral view (E with damaged atrium). (C) Same, anterior view. Scale line 0.5 mm.

REMARK: The exceptionally narrow cymbium (on both palps; Fig. 34C) of the holotype (the only available male) may not be characteristic of this species. The cymbium shape in P. selatan sp. n. could be as variable as in P. picea (cf. Fig. 28E, J).

RELATIONSHIPS: The new species is most similar and probably most closely related to P. deelemanae sp. n.; both appear closer to P. nigra , P. armata and P. korinchica than to the remaining species in the same group.

DISTRIBUTION: Known only from the type locality in southern Sumatra (Fig. 1, locality 35).

BIOLOGY: The spiders were collected from typical webs under decaying logs on the floor of a lush rain forest.

Perania spp. MATERIAL EXAMINED: MHNG, sample 29b; 1 ♀; Indonesia, Sumatra, North Sumatra

Province, 5 km N of Brastagi, Tongkoh (about 3°14’20”N, 98°30’30”E), 1450 m (mixed pine forest with many epiphytes); 3.XII.1989; leg. D. Burckhardt, I. Löbl & D. Agosti. – MHNG, sample SIM-01/03; 2 juveniles; Indonesia, Lingga Archipelago, Lingga Island , waterfall about 7 km N of Daik (00°08’53”S, 104°36’13”E), 60 m (rain forest along stream) ; 13.-15. VI.2001; leg. P. J. Schwendinger. – MHNG, sample SIM-01/04; 1 juvenile; Indonesia, Lingga Archipelago, Singkep Island, Batu Ampar Waterfall , about 10 km NW of Dabo (00°29’31”S, 104°28’31”E), 80 m (rain forest along stream); 17 ./ 18. VI.2001; leg. P. J. Schwendinger. – SMF; 1 juvenile; Malaysia (peninsula), Pahang State, Fraser’s Hill, Telecom loop (3°43’6.3”N, 101°45’9.86”E), 1300 m (primary forest along road) ; 16.VI.2013; leg. P. Jäger. All these specimens were collected by sifting.

REMARKS: The single female from near Brastagi (Fig. 1, locality 36) is the smallest known adult Perania specimen (total length 4.0 mm). It has a small conical tubercle on the clypeus, its anterior opisthosomal plate is completely (posteriorly and laterally) fused with the pulmonary plate (in other Perania spp. this is only the case in males), as are its spiracular plates (not so in other Perania females), it has the largest rudiment of a preanal plate among all Perania females examined (the latter three characters plesiomorphic), and its spermathecae contain a pair of internal ventral chambers. This specimen thus obviously represents an additional new species in the nigra -group, but without a conspecific male I do not want to formally describe and name it.

The three juveniles from two islands in the Lingga Archipelago (Fig. 1, localities 37-38) clearly belong to a Perania species (and not to a Paculla which co-occurs on the same islands) and thus are the only specimens of this genus from outside mainland SE-Asia and Sumatra.

The juvenile from Fraser’s Hill (Fig. 1, locality 24A) could belong to P. coryne , to P. cerastes or to an undescribed species.