Prothemenops irineae, Schwendinger, Peter J. & Hongpadharakiree, Komson, 2014

Schwendinger, Peter J. & Hongpadharakiree, Komson, 2014, Three new Prothemenops species (Araneae: Idiopidae) from central Thailand, Zootaxa 3893 (4), pp. 530-550 : 532-537

Prothemenops irineae sp. n.

Figures 1–4 , 11 C, F, 12

Type material. THAILAND, Prachuap Khiri Khan Province, Kuiburi District, Khao Sam Roi Yot National Park , site 1, 5– 80 m, secondary forest on limestone: male holotype (matured 5.IX.2012), 5 male paratypes (matured 29.XI.2011, 7.VIII., 12.VIII., 14.VIII., 1.X.2012), 6 female paratypes (one of them the allotype); 3.VII.2011; leg. P.J. Schwendinger, K. Hongpadharakiree & D. Manathamkamon; sample TH-11/04. Khao Sam Roi Yot National Park , site 2, 50 m, secondary forest on limestone: 1 male paratype (matured 21.IV.2014), 2 female paratypes; 21.XII.2012; leg. K. Hongpadharakiree & D. Manathamkamon. 1 male paratype (THNHM-I-2014-00001) and 1 female paratype (THNHM-I-2014-00002) deposited in THNHM, all other specimens (without registration numbers) in MHNG.

Other material examined. Same data as for holotype; 2 females, 1 penultimate male, 2 juveniles (all partly decomposed; deposited in MHNG).

Etymology. This species is named after Darika Manathamkamon, nicknamed “Irine”, the wife of the second author, who first discovered this new species.

Diagnosis. Distinguished from P. siamensis by males with a more slender palpal tibia carrying a much shorter retroventral apophysis lacking spicules; palpal organ with a basally narrower embolus equipped with an indistinct para-embolic apophysis; tibia of leg I more slender, without coupling spurs and megaspines; patella III with fewer (5–8 instead of 9–10) prodorsal spines; tarsus III aspinose (6/7 spines in holotype of P. s i a m e ns i s). Females can be distinguished from those of P. siamensis by vulva with smaller, more globular receptacular bases, and receptacular stalks and heads bent dorsad instead of outward (ectad); tibia I and metatarsus III with weak scopula (absent in both paratypes of P. s i a m e ns i s); lunate prolateral depression of same colour as rest of palpal coxa (lighter in both paratypes of P. siamensis ). Distinguished from P. khirikhan sp. n. by palp of males possessing a shorter, more distally situated tibial apophysis, and a smaller para-embolic apophysis; females with a scopula on tibia I and with slightly larger receptacular bases. Distinguished from P. phanthurat sp. n. by larger body size; males with narrower apophysis lacking spicules on palpal tibia, with angular para-embolic apophysis on retrolateral side of embolus (crescent-shaped and situated on posterior side in P. phanthurat sp. n.), without sigmoid, elongate, subapical spine on prolateral side of tibia I; females with lunate prolateral depression of same colour as rest of palpal coxa, and with distinct scopula on tarsus III (rudimentary in P. phanthurat sp. n.) and on metatarsus III (absent in P. phanthurat sp. n.).

Description. MALE (holotype). Colour in alcohol ( Fig. 2 A; for colouration of live males, see Fig. 3 A–B): carapace, dorsal sides of leg femora and of palpal femora, and distal part of chelicerae reddish brown; coxae and trochanters plus proximal portion of chelicerae and distal half of cymbium brown; patellae to tarsi light brown; all tarsi with a cream-coloured median zone (= pseudosegmentation). Anterior portion of dorsal side of opisthosoma grey-brown, with an indistinct light central area; posterior portion of opisthosoma with six dark transversal bands interconnected along mid-line, their lateral ends tapering and dissolving into dark spots. Booklung plates light orange-brown; rest of opisthosoma (including spinnerets) light yellow-brown. Ventral side of whole animal generally much paler than dorsal side.

Total length 15.0. Carapace 5.8 long, 4.8 wide, hirsute, covered with fine white adpressed hairs, with small dark bristles on both sides of eye mound, and with strong dark bristles on eye mound, on lateral and posterior margin of carapace, on coxal elevations and on area behind fovea. Pars cephalica low ( Fig. 2 C). Fovea slightly recurved (median portion straight, both ends recurved), narrow, occupying 10% of carapace width at that point, with a distinct, narrow indentation in its posterior margin ( Fig. 2 A, L). Eye group ( Fig. 2 A, E) 0.83 long, front width 0.68, back width 0.93, occupying slightly less than one-third of “head” width, raised on low mound carrying an extra-long sigmoid bristle between AME and ALE ( Fig. 2 C, E). MOQ 0.47 long, front width 0.61, back width 0.60. Eye diameters: AME 0.31, ALE 0.29, PME 0.24, PLE 0.30. Sternum 3.1 long, 2.5 wide; all sigilla small, anterior two pairs very close to margin, posterior pair slightly more distant from it. Labio-sternal suture very short but not interrupted in middle (reduced to thin transversal stripe and essentially interrupted in middle in types of P. siamensis , see Schwendinger 1991: 233, fig. 5). Labium 0.4 long, 0.9 wide, without cuspules or spicules, with relatively long bristles in two groups on anterior margin ( Fig. 2 K). Palpal coxae 1.9 long, 1.0 wide; lunate prolateral zone of ventral side slightly depressed and of same colour as rest of article; some prolateral-proximal bristles slightly swollen at base ( Fig. 2 K). Chelicerae with sessile rastellum composed of six stout blunt spines in two rows (four spines in anterior row, two in posterior); cheliceral groove with 7/7 teeth on promargin plus 3/5 tiny denticles in a median row.

Legs 3214; lengths: leg I 17.7 (4.8 + 3.0 + 3.9 + 3.9 + 2.1), leg II 16.1 (4.5 + 2.5 + 3.5 + 3.6 + 2.0), leg III 14.8 (4.0 + 2.0 + 2.8 + 3.8 + 2.2), leg IV 21.1 (5.3 + 2.7 + 5.1 + 5.4 + 2.6). Three relatively weak, light, glabrous longitudinal stripes (two dorsal and one retrolateral) on all femora of palps and legs; the retrolateral one on palps and legs I–II shorter than on legs III–IV. Two such dorsal stripes (wider but less distinct than on femora) also on all patellae and on tibia of palp. Tibia I and metatarsus I without modifications ( Fig. 2 I); metatarsi I–II each with one strong proventral spine and two weak retroventral spines (stiff bristles) ( Fig. 2 I–J). Patella III with row of six short prodorsal spines on right side and with row of five such spines on left side; all tibiae and metatarsi of legs with ventral spines, those on posterior legs more numerous and extending to pro- and retrodorsal sides; all leg tarsi aspinose (but see “Variation”). Filiform trichobothria on tibiae to tarsi of legs; club-shaped trichobothria ( Fig. 1 C, showing female) in distal two-thirds of metatarsi only ( Fig. 1 A–B, showing female). Scopula thin on entire ventral side of tarsus I and II, very thin on entire ventral side of tarsus III, very thin and only in distal two-thirds of tarsus IV; thin distally and very thin proximally on ventral side of metatarsi I–II (on II slightly denser than on I; Fig. 2 I–J), very thin and only in distal fourth on metatarsus III, absent from metatarsus IV. Scopular setae hairbrush-shaped ( Fig. 1 D, showing female). Tarsal organ low, cowpat-shaped ( Fig. 1 E–F, showing female). Paired tarsal claws armed with row of 5–7 teeth (second tooth from base largest); unpaired claws bare.

Palp 7.2 long (2.5 + 1.8 + 1.9 + 1.0), slender. Relatively slender tibia with short retroventral apophysis situated some distance from distal margin and carrying only bristles (no spines or spicules; Fig. 2 F–H). Short cymbium with rounded lobe prodistally and rather angular, indistinct lobe retrodistally, carrying weak spines (stiff bristles) on distal margin plus club-shaped trichobothria on dorsal surface. Palpal organ with oval tegulum, its distal haematodocha vertically divided by narrow pigmented stripe and not reaching base of embolus ( Figs 2 H, 4A–B); embolus long, slender and bent away from axis of palp; base of embolus occupying more than half of total embolus length, ending in an indistinct, short triangular para-embolic apophysis retrolaterally; apex of embolus thin, flexible, flagelliform ( Figs 2 F–H, 4A–B).

Opisthosoma covered with adpressed white hairs (only on dorsal side) and erect dark bristles (strongest in anterodorsal region), 6.8 long, 4.3 wide. PMS 0.5 long, PLS 2.4 long: apical article 0.4 (slightly longer than wide), median article 0.7, basal article 1.3 long.

FEMALE (allotype). As in male, except for: Colour in alcohol generally more greyish; chelicerae and dorsal pattern of opisthosoma distinctly darker ( Fig. 2 B; for colouration of live females see Fig. 3 C–D).

Total length 21.5. Carapace 7.6 long, 6.1 wide, bristles on its lateral and posterior margins thinner than in male; pars cephalica moderately raised ( Fig. 2 D), clearly higher than in male. Fovea occupying 15% of carapace width at that point; median portion of anterior margin slightly procurved, both ends recurved; posterior margin with wider indentation than in male. Eye group 1.10 long, front width 0.83, back width 1.38, occupying slightly less than onethird of “head” width. MOQ 0.59 long, front width 0.75, back width 0.74. Eye diameters: AME 0.36, ALE 0.31, PME 0.15, PLE 0.37. Sternum 4.4 long, 3.3 wide, its sigilla slightly more distinct than in male. Labium 0.7 long, 1.3 wide. Palpal coxae 2.8 long, 1.5 wide, carrying 43/46 thick cuspules proximally-prolaterally; lunate prolateral zone of ventral side slightly depressed and mostly of same colour as rest of article except for narrow light band along prolateral margin next to long, curved, reddish marginal hairs. Chelicerae more robust than in male; rastellum composed of about 20 short strong spines in 6–7 rows; cheliceral furrows with 7/7 teeth on promargin and 6/7 denticles (larger than in male) in a median row. Legs stouter than in male; lengths: leg I 15.4 (4.7 + 3.6 + 3.2 + 2.5 + 1.4), leg II 14.0 (4.4 + 3.1 + 2.7 + 2.4 + 1.4), leg III 12.8 (3.9 + 2.6 + 2.2 + 2.7 + 1.4), leg IV 19.8 (5.4 + 3.6 + 4.6 + 4.5 + 1.7). Patella III with 9/11 prodorsal spines, dorsal bristles stronger than in male; prolateral side of femur IV distally with dense group of much stronger bristles than in male. Scopula dense on entire ventral side of tarsi and metatarsi I–II ( Fig. 1 A–B), thin on entire ventral side of tarsus III, in distal half of ventral and prolateral sides of metatarsus III and distally on prolateral side of tibia I, absent on leg IV; scopula of palp dense on entire ventral side of tarsus and proventrally to prolaterally in distal half of tibia. All tarsi of palps and legs integral (not pseudosegmented as in males) and armed with spines: two widely spaced basal ones and 3/4 closely spaced distal ones on palpal tarsus; three distoventral ones on tarsi I–II; a prodorsal one plus 7–10 ventral ones on tarsus III; 11–12 prolateral, ventral and retroventral ones on tarsus IV; spines on other leg articles mostly as in male. Paired tarsal claws with row of 4–5 teeth, unpaired claws bare; palpal claw with row of 3/4 teeth.

Opisthosoma 10.0 long, 6.9 wide. PMS 0.6 long; PLS 3.0 long: apical article 0.5, median article 0.9, basal article 1.6 long.

Vulva (of paratypes; Fig. 4 C–G) with wide short atrium running into two widely separated sperm receptacles composed of thick-walled, strongly pigmented, ovoid basal portion (called “sclerotized lateral pouches” in description of P. siamensis , see Schwendinger 1991: 235, fig. 12), and slightly less pigmented, tubuliform, convoluted stalk terminating in slightly enlarged, rounded head. The latter as large as or smaller than base, and distally distinctly less sclerotized and pigmented than stalk. Receptacular stalk and head bent dorsad ( Fig. 4 C).

Variation. Carapace lengths of seven males (and the six largest females in parentheses) range 5.1–7.0 (6.8–8.3), carapace widths 4.3–5.7 (5.3–6.3). In the holotype and allotype the AME is slightly larger than the ALE, but in most other conspecific specimens examined the AME is as large as or slightly smaller than the ALE. The posterior margin of the fovea has a more or less distinct median indentation in all males and four females, whereas in two females this is not visible (presumably hidden under the overlapping anterior margin of the fovea). Patella III of males has 5–8 prodorsal spines in an irregular row, that of females 6–12. Tarsus IV is aspinose in four males (including the holotype); it has 0/2, 1/1 and 3/9 spines in the other three males. Tarsi I–III are aspinose in all males. The male from the second locality has a slightly smaller tibial apophysis on its palp and a less distinct para-embolic apophysis than the males from the first locality. All eight female paratypes, two other females which were killed and overgrown by the pathogenic fungus Nomourea atypicola , and a subadult male have a thin scopula on tibia I (very indistinct in subadult male, distinct in all others) and on metatarsus III. Variation in the shape of the vulva of four females, see Fig. 4 D–G.

Relationships. Strong morphological similarities in copulatory organs of both sexes show that this species is probably the closest relative of P. khirikhan sp. n.

Distribution. Prothemenops irineae sp. n. was found at three sites (within a distance of 3 km) in the small isolated limestone massif that comprises the Khao Sam Roi Yot National Park ( Fig. 12 , locality 2). Mature specimens are available from only two of these sites, but we believe that all Prothemenops in that park are conspecific. The new species appears to be locally abundant but restricted to this massif.

Biology. The spiders were found on the steep slopes of limestone hills covered with a low, thorny secondary vegetation interspersed with introduced Opuntia (Euphorbiaceae) . They lived in burrows which were usually unbranched and closed by a single thin trapdoor ( Fig. 11 F) in large spiders, Y-shaped and closed by two trapdoors ( Fig. 11 C) in small and medium-sized spiders. The largest burrow (of a female) was about 15 cm long, and had a 1.75 cm long and 2.2 cm wide trapdoor. Adult males (all raised in captivity) had 1.00– 1.25 cm long and 1.15–1.40 cm wide trapdoors; two of these males had Y-shaped burrows with two trapdoors of different sizes.

The first male matured at the end of December 2011 after less than six months in captivity; five others matured in August to October of the following year; the last one matured in late April 2014, presumably an untimely date caused by conditions during 16 months of captivity. When disturbed, adult males and large females display an aggressive defence behaviour similar to that of theraphosid spiders: they raise their palps, first pair of legs and the prosoma ( Fig. 3 B), and jump (only for a short distance) towards or even onto the object that threatens them. Occasionally, the spiders then land on their back. Moults of two large females were recorded in mid-September 2012 and in late April 2013. As the spiders moult inside their burrows and then usually deposit their heavily fragmented exuviae at the bottom of the burrow, moults are rarely observed. In captivity two females were killed in their burrows by Nomuraea atypicola (Yasuda) Samson , a common pathogenic fungus of spiders ( Greenstone et al. 1987) which has also been observed in other Prothemenops species ( Schwendinger 1996: 579).

Figures

FIGURE 1. Prothemenops irineae sp. n., SEM micrographs of female (not a paratype). A, dorsolateral view of metatarsus and tarsus of right leg I showing distribution of club-shaped trichobothria (no clavate trichobothria present). B, same in dorsodistal view. C, detail of club-shaped trichobothrium. D, scopular setae on metatarsus I. E, tarsal organ (with adhering dust particles) of right tarsus I. F, tarsal organ of right tarsus II.

FIGURE 2. Prothemenops irineae sp. n., male holotype (A, C, E – L) and female allotype (B, D). A – B, habitus, dorsal view. C – D, carapace, lateral view. E, eye group, dorsal view. F, distal part of right palp, retrodorsal view. G, same, proventral view. H, same, ventral view. I, tibia and metatarsus of right leg I, ventral view. J, tibia and metatarsus of right leg II, ventral view. K, labium and proximal part of left palpal coxa showing bristles with slightly swollen bases. L, recurved fovea with indentation in posterior margin.

FIGURE 3. Prothemenops irineae sp. n., A – B, habitus of two males (B, male in defence posture). C – D, habitus of two females.

FIGURE 4. Prothemenops irineae sp. n. A, right palpal organ of male holotype, retrolateral and slightly distal view. B, same, ventral and slightly distal view. C, left receptacle of exuvia of paratype, ental view (anterior is to the right, posterior to the left). D – G, vulvae of four female paratypes, dorsal view (D = allotype). Abbreviations: a = genital atrium, ae = apex of embolus, b = base of receptacle, be = base of embolus, dh = distal hematodocha, h = head of receptacle, pa = para-embolic apophysis, s = stalk of receptacle, st = subtegulum, t = tegulum, ue = uterus externus. Scale lines 0.1 mm (C), 0.5 mm (A – B, D – G).

FIGURE 11. Burrows of Prothemenops khirikhan sp. n. (A – B), P. irineae sp. n. (C, F) and P. phanthurat sp. n. (D – E). A, intact straight burrow just below the soil surface (1 a = open front door, 1 b = closed hind door). B, three such burrows close to each other (1 a – 3 a front door, 1 b – 3 b hind door of each burrow); upper side of longest burrow (shown in A) removed to show its shallow course. C, typical Y-shaped burrow still intact, with its two doors open and distinctly apart from each other. D, Yshaped burrow (in captivity) dug up to show its below-ground shape. E, Y-shaped burrow running into limestone crack, with both doors close to each other. F, straight, deep, blind-ending large burrow with its single door closed.

FIGURE 12. Map of Southeast Asia (without southernmost Thailand and without peninsular Malaysia) showing localities of the three species treated in here (squares with numbers) and the currently known geographic range of the genus Prothemenops (grey area). 1, P. khirikhan sp. n.; 2, P. irineae sp. n.; 3, P. phanthurat sp. n.