Perania utara, 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 : 625-628

Perania utara sp. n. Figs 18, 36C, 37C

HOLOTYPE: MHNG, sample Sum-06/28; Ƌ; Indonesia, Sumatra, North Sumatra Province (= Sumatera Utara), hill about 1 km NE of Sibolga (1°45’22”N, 98°46’48”E), 300 m; 26.VI.2006; leg. P. J. Schwendinger.

PARATYPE: 1 ♀ “ allotype ” with same data as for holotype .

ETYMOLOGY: Indonesian: “utara” = north, northern. Noun in apposition.

DIAGNOSIS: Similar to P. nigra , both sexes distinguished by posteriorly narrower carapace without modifications in “thoracic” portion. Females distinguished by spermathecae carrying distinct external pouches (not just chambers inside the spermathecae) on ventral surface, these long and distinctly separated from each other; anterior margin of spermathecae not invaginated; dorsal collar of vulva much wider than in P. nigra ; anterior opisthosomal plate and preanal plate of female completely fragmented; posterior side of opisthosoma with eight horizontal, strap-like plates of variable width. Male with tibia I and metatarsus I carrying many more conical setal bases than males of P. nigra , a few conical setal bases also on metatarsus II; palpal organ much shorter and stouter, with a deeper apex.

DESCRIPTION OF MALE (holotype): Colour (in alcohol) generally brown, carapace, chelicerae and ventral sclerites dark brown; membranous parts of opisthosoma light grey-brown. “Thoracic” portion of carapace unusually narrow in dorsal view. Clypeus without median process (Fig. 18A). Fovea deepened and slightly widened in anterior portion. Total length 6.7. Carapace 3.5 long, 2.1 wide. Eye sizes and interdistances: PME 0.21 long, separated by 0.24; ALE 0.22 long; ALE-PLE 0.06; PLE 0.22 long, separated by 1.07. Labium 0.6 long, 0.8 wide. Sternum 2.2 long, 1.5 wide. Chelicerae without modifications; with two teeth on anterior margin of fang furrow.

Palp 2.6 long (0.8+0.4+0.7+0.7), femur smooth (setal bases not visibly elevated). Cymbium (Fig. 18C) of typical shape, with a pointed apex. Palpal organ quite short and stout; embolus with relatively deep base and indistinctly bifid apex with a pointed dorsad-directed subterminal lamella and a lobate distad-directed embolic part; distal margin of apex slightly invaginated and carrying three teeth (Fig. 18B-D).

Legs 34=21. Femora granular (with slightly elevated setal bases). About 50 quite large conical setal bases prolaterally to ventrally on metatarsus I, about 10 large ones prolaterally and about 50 smaller ones proventrally and ventrally on tibia I; four smaller ones proventrally and prolaterally on metatarsus II, non on tibia II. Paired leg claws with a row of 9-12 teeth; unpaired leg claws with one denticle. Leg I 12.5 long (3.8+1.2+3.9+2.5+1.1), leg II 10.0 long (3.0+1.0+2.8+2.2+1.0), leg III 7.6 long (2.3+0.8+1.8+1.8+0.9), leg IV 10.0 long (2.9+0.9+2.7+2.6+0.9).

Opisthosoma 3.5 long, 2.4 wide. Dorsal scutum 3.2 long, 2.3 wide, somewhat oval, its surface smooth. Most microplates on posterior side of opisthosoma isolated but closely packed, some fused (especially in first, third, fourth, fifth and sixth row from above; Fig. 37C). Pulmonary plate 2.3 long, 2.0 wide. Anterior pair of ventrolateral plates largely free, only their posterior tips fused with margin of pulmonary plate. Postgenital plate completely fused to posterior margin of pulmonary plate, with a sclerotised suture linking them. Preanal plate 0.2 long, 0.7 wide, somewhat elliptical (Fig. 36C). Anal plate 0.7 long, 1.0 wide.

DESCRIPTION OF FEMALE (“ allotype ”; dissected): As in male, except for the following. Total length 7.2. Carapace 3.6 long, 2.2 wide. PME 0.22 long, 0.35 apart; ALE 0.21 long; ALE-PLE 0.07; PLE 0.21 long, 1.21 apart. Labium 0.6 long, 0.9 wide. Sternum 2.2 long, 1.6 wide. Palp 2.7 long (0.8+0.4+0.6+0.9). Legs 3241; tibiae and metatarsi I-II without conical setal bases. Paired leg claws with a row of 11-14 teeth. Leg I 11.2 long (3.3+1.1+3.3+2.4+1.1), leg II 9.5 long (2.8+1.0+2.6+2.1+1.0), leg III 7.6 long (2.2+0.9+1.8+1.8+0.9), leg IV 9.9 long (2.9+0.9+2.6+2.5+1.0).

Opisthosoma 4.4 long, 3.4 wide. Anterior plate fragmented into microplates, two of them slightly larger then the rest. Dorsal scutum 3.0 long, 1.9 wide, its surface with a few scattered low tubercles and low ridges. All microplates flat; median microplates in bands on posterior side of opisthosoma fused, forming eight strap-like horizontal plates, the uppermost one fused to posterior margin of dorsal scutum. Pulmonary plate 2.0 long, 2.1 wide, its posterior margin almost straight. Preanal plate fragmented into a group of slightly enlarged microplates. Anal plate 0.8 long, 1.0 wide.

FIG. 18

Perania utara sp. n.; male holotype (A-D) and female “ allotype ” (E-G). (A) Carapace, dorsal view. (B) Left palp, ventral view. (C) Same, dorsal view. (D) Same, retrolateral view. (E) Vulva, dorsal view. (F) Same, ventral view. (G) Same anterior view. Abbreviation: vp = external ventral pockets. Scale lines 1.0 mm (A; B-D), 0.5 mm (E-F; G).

Vulva with short, very wide anterior collar; ventral wall of genital atrium and spermathecae pigmented throughout; spermathecae completely fused in the middle, elliptical, common anterior margin widely arched, not invaginated and without anterolateral trenches, with indistinctly outlined porepatches; a pair of paddle-shaped external pouches (filled with sperm and therefore clearly serving as receptacles) attached to posterior portion of ventral side of spermathecae (Fig. 18E-G).

RELATIONSHIPS: The relatively short and stout palpal organ resembles that of P. egregia sp. n. but that is probably a homoplasy. The ovoid bulbus of the palpal organ and the paired modifications in the ventral wall of the vulva indicate that P. utara sp. n. could be sister to the other Perania known from Sumatra. However, these similarities may be plesiomorphies (see Discussion).

DISTRIBUTION: Known only from the type locality, a small hill at the northern outskirts of Sibolga city (Fig. 1, locality 25).

BIOLOGY: The specimens examined were collected by sifting leaf litter in a remnant patch of rain forest near the top of a small hill. No webs were seen, but it is likely that P. utara sp. n. constructs irregular sheetwebs as typical for spiders of this genus.

THE PERANIA NIGRA SPECIES GROUP

DIAGNOSIS: Small to large species characterized by “thoracic” portion of carapace in both sexes either unmodified, or with a pair of long and spine-like or low and hump-like processes; fovea anteriorly with a more or less distinctly widened pit. Females with spermathecae containing sclerotised internal chambers in the ventral wall; porepatches distinctly outlined and extending far onto dorsal side of spermathecae; ventral side of spermathecae between porepatches and internal chambers unpigmented; ventral wall of genital atrium entirely or only medially pigmented; common anterior margin of spermathecae more or less distinctly invaginated in the middle; anterior opisthosomal plate entire or fragmented into microplates of various sizes; preanal plate rudimentary or completely fragmented into microplates. Males with bulbus of palpal organ ovoid; embolus long and distinctly sigmoid; clypeus unmodified, or with a short tooth-like clypeal process, or with a long digitiform clypeal process (but never with a widened apex); chelicerae unmodified; femora of legs and palps smooth.

SPECIES INCLUDED: Perania armata , P. deelemanae sp. n., P. harau sp. n., P. korinchica , P. nigra , P. picea , P. selatan sp. n. and an undescribed species from Brastagi.

DISTRIBUTION: Only known from the Indonesian island of Sumatra (Fig. 1, localities 26-36).