Perania korinchica Hogg, 1919

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 : 644-646

Perania korinchica Hogg, 1919 Fig. 30

Perania korinchica Hogg, 1919: 81-83 , pl. 7, fig. 1a-b, d-f [description of female (prosoma only)].

Perania picea ( Thorell, 1890) . – Shear, 1978: 41 (note on composite specimen). – Lehtinen, 1981: 16 (synonymisation). – Platnick, 2013 (listing as a junior synonym).

TYPE: Natural History Museum London; prosoma of ♀ holotype (not examined); Indonesia, Sumatra, Jambi Province, Korinchi Peak (= Gunung Kerinci), Sungei Kumbang , 4700 ft; early 1914; leg. H. C. Robinson & C. Boden Kloss.

NEW MATERIAL EXAMINED: MHNG, sample Sum-00/12; 1 mature Ƌ, 1 juvenile Ƌ; Indonesia, Sumatra, Jambi Province, Gunung Kerinci , footpath to summit, W of Kersik Tua (about 1°43’30”S, 101°15’30”E), 1800-1980 m; 16.II.2000; leg. P. J. Schwendinger.

DIAGNOSIS: Male similar to that of P. nigra , distinguished by: larger size, a short process on clypeus, no paired humps on “thoracic” portion of carapace, smaller tubercles on lateral margin of carapace, a more strongly bent embolus, a deeper subterminal lamella with a more rounded upper corner, and a slightly larger, hook-shaped embolic part situated further back and directed ventrad.

DESCRIPTION OF MALE (newly moulted specimen): Colour (in alcohol) mostly light brown, carapace and chelicerae slightly darker; dorsal scutum of opisthosoma grey-brown, membranous parts of opisthosoma cream-coloured. Clypeus with short (occupying only 3% of carapace length), asymmetrically pointed median process (Fig. 30A-B). Fovea distinct, its anterior portion a round pit, its posterior portion a shallow longitudinal furrow. Total length 7.2. Carapace 3.7 long, 2.4 wide. Eye sizes and interdistances: PME 0.29 long, separated by 0.09; ALE 0.27 long; ALE-PLE 0.06; PLE 0.25 long, separated by 0.90. Labium 0.7 long, 0.9 wide. Sternum 2.4 long, 1.7 wide. Chelicerae without modifications; with two teeth on anterior margin of fang furrow.

Palp 3.4 long (1.0+0.5+0.9+1.0). Cymbium (Fig. 30C, E) of typical shape, with a pointed but not unusually narrow apex. Palpal organ with ovoid bulbus and long sigmoid embolus, its median portion deep and in contact with bulbus on both palps; apex of embolus with a deep, paddle-shaped and obliquely truncate subterminal lamella, and with a small, shallow, hook-shaped and ventrad-directed embolic part distinctly set back from distal margin of embolus (Fig. 30C-H).

FIG. 30

Perania korinchica , male. (A) Carapace, dorsal view. (B) Same, lateral view. (C) Distal portion of left palp, proventral view. (D) Left palpal organ, ventral view. (E) Left palpal organ and cymbium, retrodorsal view. (F) Left palpal organ, distal view. (G) Left embolus, distal view (slightly more inclined than in F). (H) Right embolus, distal view. Scale lines 1.0 mm (A-B; C-H).

Legs 3241. Seven conical setal bases distributed over almost entire length of metatarsus I prolaterally and proventrally, three/five over distal third of tibia I prolaterally. Paired leg claws with a row of 10-14 teeth; unpaired leg claws with one den- ticle. Leg I 13.0 long (3.8+1.5+4.1+2.4+1.2), leg II 10.3 long (3.0+1.2+2.9+2.1+1.1), leg III 8.1 long (2.5+1.0+2.0+1.9+0.7), leg IV 10.5 long (3.1+1.1+2.7+2.6+1.0).

Opisthosoma 3.9 long, 2.7 wide. Dorsal scutum 3.5 long, 2.4 wide, somewhat oval, posteriorly wider than anteriorly, its posterior margin straight, smooth. All microplates flat, those in five bands on posterior side of opisthosoma partially fused, forming broken strap-like horizontal plates. A few lateral microplates of lowest band in anterior portion of opisthosoma fused with each other (representing remnants of lateral plates) before running into lateral margin of pulmonary plate. Pulmonary plate 3.0 long, 2.2 wide; genital region flat. Anterior pair of ventrolateral plates largely fused with lateral margin of pulmonary plate, only their anterior tips free. Postgenital plate largely fused to pulmonary plate, with a narrow membranous slit behind gonopore marking border between both plates. Preanal plate 0.2 long, 0.9 wide, irregularly trapezoid. Anal plate 0.7 long, 1.1 wide.

FEMALE: The holotype of this species is the prosoma of a female ( Hogg, 1919: 81-83, fig. 1a-b, d-f, not fig. 1c) and it thus provides hardly any distinctive characters. The isolated opisthosoma described and illustrated together with the holotype prosoma actually belongs to a Leucauge female in the distantly related spider family Tetragnathidae (see Shear, 1978: 41; Lehtinen, 1981: 16).

RELATIONSHIPS: Morphology of the male palp indicates a close relationship with P. nigra and P. armata .

DISTRIBUTION: Known only from the type locality, Gunung Kerinci , an active volcano and the highest mountain of Sumatra (Fig. 1, locality 32) .

BIOLOGY AND REMARKS: The new specimens of P. korinchica and P. picea were all collected during my ascent to the summit of Gunung Kerinci and were all put into the same sample (Sum-00/12). According to field notes, the P. korinchica specimens were probably collected at 1800 m, from under decaying wood on the floor of a very humid, upland rain forest near the first shelter along the footpath to the summit.

As two Perania species are present on Mt Kerinci, one cannot rule out that the female holotype of P. korinchica (represented only by a prosoma without relevant specific characters) belongs to P. picea , but body size and altitudinal occurrence indicate otherwise. The two species on Mt Kerinci differ in size, and it seems that they occur at different altitudes: the larger one higher up (at 1980 m) than the smaller one (at 1800 m). The holotype of P. korinchica was collected at a relatively low altitude (4700 feet = ca 1430 m), and it is clearly smaller than the females of P. picea examined (carapace length of P. korinchica holotype: 4.5, of P. picea females: 4.8-4.9). Thus it is most likely that the new specimens from 1800 m are conspecific with the type of P. korinchica .

An embolus, which is so strongly curved upwards that its median portion is in contact with the bulbus of the palpal organ, was not found in any other Perania species. It may, however, not be a specific character but a deformation caused by the fact that the spider was preserved shortly after moulting and therefore the palpal organs may not be fully expanded. The asymmetrical clypeal process is presumably due to individual variation and not characteristic for the species.