Prothemenops khirikhan, 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 : 538-542

Prothemenops khirikhan sp. n.

Figures 5–7 , 11 A–B, 12

Type material. THAILAND, Prachuap Khiri Khan Province, Thab Sakae District, Nam Tok Huay Yang National Park , 90 m, secondary forest near stream : male holotype (matured 1.XI.2012) , 8 male paratypes (matured 3.IX., 11.X., 26.X., 26.X.2011, 6.IX., 27.IX., 19.XI.2012, beginning of I.2013) , 2 female paratypes; 2.VII.2011; leg. P.J. Schwendinger, K. Hongpadharakiree & D. Manathamkamon; sample TH-11/03. Same locality ; 1 male paratype (matured 1.VIII.2010) , 2 female paratypes; 28.II.2010; leg. K. Hongpadharakiree & D. Manathamkamon . 1 male paratype (THNHM-I-2014-00003) and 1 female paratype (THNHM-I-2014-00004) deposited in THNHM, all others (without registration numbers) in MHNG.

Other material examined. Same locality; 1 juvenile; 28.II.2010; leg. K. Hongpadharakiree & D. Manathamkamon (deposited in MHNG).

Etymology. Thai: khiri = mountain, khan = territory. The species name (a noun in apposition) refers to the province in which this species was discovered.

Diagnosis. Distinguished from P. siamensis by males possessing a more slender palpal tibia carrying a shorter and more proximally situated apophysis lacking spicules; palpal organ with a basally narrower embolus carrying an angular, more distally situated para-embolic apophysis; tibia of leg I more slender, without coupling spurs and megaspines. Females 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). Differs from P. i r i ne a e sp. n. by males having a longer, relatively narrower and more proximally situated apophysis on palpal tibia, a relatively larger embolus carrying a more pronounced para-embolic apophysis; females possessing slightly smaller receptacular bases and lacking a prolateral-distal scopula on tibia I. Different 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, tibia I without a scopula.

Description. MALE (holotype). Colour in alcohol ( Fig. 5 A; for colouration of live male see Fig. 6 A): eye mound dark except for contrasting (more so than in P. irineae sp. n.) light median area between AME and ALE ( Fig. 5 D); carapace brown, with dark mottling, especially on pars cephalica; legs and palps brown, femora appearing darker due to dense cover of fine grey hairs (much thinner cover of such hairs on other articles); all tarsi with cream-coloured median zone (= pseudosegmentation). Dorsal side of opisthosoma grey-brown, with slightly paler central area in anterior half and with pattern of six dark wide bands (interconnected along mid-line, laterally dissolving into dark spots) in posterior half. Ventral side of opisthosoma light brown, booklung plates slightly darker, spinnerets paler. Ventral side of whole animal paler than dorsal side.

Total length 15.0. Carapace 6.8 long, 5.5 wide, hirsute, with fine white, adpressed hairs everywhere, especially dense (more so than in P. i rineae sp. n.) in two paramedian bands between eye mound and fovea, with small dark bristles on both sides of eye mound, and with long and strong, dark bristles on eye mound, on lateral and posterior margin, on coxal elevations and on area behind fovea. Pars cephalica low. Fovea slightly recurved (median portion straight, both ends recurved), narrow, occupying 14% of carapace width at that point, seemingly without indentation in its posterior margin. Eye group in three rows, 0.96 long, front width 0.87, back width 1.16, occupying slightly less than one-third of “head” width, raised on low mound carrying an extra-long sigmoid bristle between AME and ALE (broken in Fig. 5 D). Eye diameters: AME 0.31, ALE 0.38, PME 0.16, PLE 0.40. MOQ 0.52 long, front width 0.70, back width 0.74. Sternum 3.6 long, 2.9 wide, with three pairs of small, very indistinct, marginal sigilla. Labio-sternal suture very short, not interrupted in middle. Labium 0.5 long, 1.0 wide, with two lateral groups of long and bent bristles on anterior margin. Palpal coxae 2.3 long, 1.1 wide; lunate prolateral zone of ventral side slightly depressed and of same colour as rest of article; bristles in proximal-prolateral corner with clearly swollen bases (more distinctly so than in males of P. irineae sp. n.). Chelicerae with rastellum not raised, composed of 16–20 stout blunt spines in several rows; cheliceral groove with 7/7 teeth on promargin plus 6/6 tiny denticles in median row.

Legs 3214; lengths: leg I 20.6 (5.6 + 3.4 + 4.5 + 4.6 + 2.5), leg II 18.8 (5.2 + 3.0 + 4.0 + 4.3 + 2.3), leg III 17.4 (4.7 + 2.4 + 3.1 + 4.6 + 2.6), leg IV 24.9 (6.3 + 3.1 + 5.8 + 6.7 + 3.0). Three light, glabrous, longitudinal stripes (two dorsal and one retrolateral) on all femora of palps and legs; retrolateral one on palps and legs I and II shorter than on legs III and IV. Two such dorsal stripes (wider but less distinct than on femora) also on all patellae and on tibia of palp. Tibia and metatarsus I without modifications ( Fig. 5 I). Metatarsus I with one weak proventral spine and two slightly stronger retroventral spines ( Fig. 5 I); metatarsus II with one weak proventral spine, one short apical spine and four slightly stronger retroventral spines ( Fig. 5 J). Patella III with row of nine short prodorsal spines on right side and with row of seven such spines on left side. All tibiae and metatarsi with ventral spines, those on posterior legs more numerous than on anterior legs and extending to pro- and retrodorsal sides. Tarsi I–II aspinose; tarsus III with one prodorsal and one retroventral spine (but see “Variation”); tarsus IV with 17/21 ventral spines. Filiform trichobothria dorsally on tibiae to tarsi; club-shaped trichobothria dorsally in distal half of metatarsi I–III and in distal two-thirds of metatarsus IV. Scopula thin on entire ventral side of tarsi I–III, absent on tarsus IV; thin on almost entire (missing proximally) ventral side of metatarsi I–II ( Fig. 5 I–J), very thin and only apically on ventral side of metatarsus III, absent on metatarsus IV. Paired tarsal claws armed with row of 5–7 teeth (median tooth largest); unpaired claw unarmed.

Palp 8.1 long (2.9 + 1.8 + 2.3 + 1.1), slender. Relatively slender tibia with a moderately long retroventral apophysis situated quite far from distal margin and carrying only bristles (no spines or spicules; Fig. 5 E–H). Short cymbium with rounded prodistal lobe and more angular retrodistal lobe, carrying very stiff bristles (or weak spines?) on distal margin plus club-shaped trichobothria on dorsal surface. Palpal organ with pyriform tegulum, its distal haematodocha vertically divided by narrow pigmented stripe and not reaching base of embolus; embolus long, slender and bent away from axis of palp; embolar base quite long and wide in ventral view (clearly wider than in P. irineae sp. n.), occupying more than half of total embolus length, ending in short but distinct, triangular paraembolic apophysis retroventrally; apical portion of embolus thin, flexible, flagelliform ( Figs 5 E, G–H, 7A–B).

Opisthosoma covered with fine, adpressed white hairs (only on dorsal side) and more erect dark bristles of different sizes (everywhere), 5.7 long, 4.0 wide. PMS 0.6 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 darker, especially carapace, dorsum of opisthosoma, chelicerae and femora of palps and legs ( Fig. 5 B; for colouration of live females, see Fig. 6 B–D). Light, glabrous longitudinal stripes on femora of palps and legs much more distinct.

Total length 21.0. Carapace 7.6 long, 6.2 wide, bristles on its lateral and posterior margins slightly thinner than in male; pars cephalica moderately raised, distinctly higher than in males. Fovea occupying 15% of carapace width at that point, median portion of anterior margin straight, both ends recurved; posterior margin with distinct median indentation. Eye group 1.12 long, front width 0.95, back width 1.44, occupying exactly one-third of “head” width. MOQ 0.58 long, front width 0.83, back width 0.90. Eye diameters: AME 0.34, ALE 0.37, PME 0.18, PLE 0.41. Sternum 4.3 long, 3.3 wide. Labium 0.7 long, 1.3 wide. Palpal coxae 2.9 long, 1.5 wide, carrying 27/30 thick cuspules proximally-prolaterally; lunate prolateral zone of ventral side slightly sunken and mostly of same colour as rest of article except for light cuticle at base of hairs on and near prolateral margin ( Fig. 5 C). Chelicerae distinctly stronger than in male; rastellum not raised, composed of about 20 short strong spines in 6–7 rows; cheliceral furrows with 7/7 teeth on promargin and 7/9 denticles (larger than in male) in a median row. Legs stronger than in male; lengths: leg I 16.0 (4.9 + 3.6 + 3.4 + 2.7 + 1.4), leg II 14.7 (4.5 + 3.2 + 3.0 + 2.6 + 1.4), leg III 13.5 (4.0 + 2.7 + 2.3 + 2.8 + 1.7), leg IV 20.1 (5.6 + 3.6 + 4.7 + 4.3 + 1.9). Patella III with 8/9 prodorsal spines, dorsal bristles not stronger than in male (unlike in P. i r i ne a e sp. n. females); prolateral side of femur IV distally with a dense group of much stronger bristles than in male.

Scopula dense on entire ventral side of tarsi and metatarsi I–II, thin and only basally on ventral side of tarsus III, absent from tibia I, from metatarsus III (but see “Variation”) and from entire leg IV; dense on entire ventral side of palpal tarsus and in distal half of prolateral side of palpal tibia. All tarsi of palps and legs integral and armed with spines: two widely spaced basal ones and four closely spaced distal ones on ventral side of palpal tarsus, 2/3 closely spaced distoventral ones on tarsus I; three such spines on tarsus II; one prodorsal plus 10/11 ventral ones on tarsus III; 10/12 prolateral to retrolateral ones on tarsus IV; two retroventral and one proventral one in proximal one-third, plus two apical ones on metatarsus I; spines on other leg articles mostly as in male. Paired tarsal claws with row of 5–6 teeth on anterior legs and 4–5 on posterior legs, unpaired claws bare; palpal claw with row of 4/5 teeth (two of them tiny).

Opisthosoma 9.8 long, 5.8 wide. PMS 0.6 long; PLS 3.0 long: apical article 0.5, median article 0.9, basal article 1.6 long.

Vulva ( Fig. 7 C) with short wide atrium and two widely separated sperm receptacles, each composed of relatively small (not clearly wider than receptacular stalk), thick-walled globular base, and tubuliform, dorsad-bent stalk terminating in rounded, lightly pigmented head of approximately same size as receptacular base.

Variation. Carapace lengths in ten males (largest female in parentheses) range 5.8–7.6 (7.6), carapace widths 4.8–6.0 (6.2). The holotype has the most deviant leg spination among males but otherwise is characteristic: it has one short apical spine (only on right side) and four long retroventral spines (on both sides) on metatarsus II (similar to the male holotype of P. siamensis with 1/2 apical, 1/2 proventral and four retroventral spines on metatarsus II; all other P. kh i r i k h an sp. n. males have no apical and only 2–3 retroventral spines) and it has one prodorsal plus one retroventral spine on tarsus III (most other males have none, one has a prodorsal spine on one side only, a second male has a retroventral spine on one side only). The number of prodorsal spines on patella III of males varies from five to ten, those of females from six to nine. The posterior margin of the fovea appears to be unmodified in most specimens; in two males it has a distinct indentation, and in one male a small pit behind the margin (both latter conditions common in P. irineae sp. n.). The four females examined all lack a scopula on tibia I, and three of them also lack a scopula on metatarsus III (weak and only prolaterally-distally in the fourth female). All males and an exuvia of a penultimate male also lack a scopula on tibia I but possess a very indistinct distoventral scopula on metatarsus III. Variation in the shape of the vulva of three females, see Fig. 7 C–E. One female is darker in colouration than others of the same population ( Fig. 6 C–D cf. Fig. 6 B). Such dark-coloured individuals were also observed in other Prothemenops species (e.g. males of P. phanthurat sp. n.).

Relationships. Strong similarities in the shape of copulatory organs of both sexes, as well as close geographical proximity, indicate that his species is probably the closest relative of P. i r i n e ae sp. n.

Distribution. Prothemenops khirikhan sp. n. is only known from the type locality in the southern part of central Thailand ( Fig. 12 , locality 1). At present this is the southern-most locality known for Prothemenops .

Biology. Unlike the other two species described here, P. k hi r i k h an sp. n. is not associated with limestone. The spiders were found in a mixed evergreen-deciduous forest near a stream. They did not live in deep Y-shaped burrows as usual for Prothemenops , but in straight burrows closed by only one trapdoor (mostly large spiders), or in very widely V- or U-shaped burrows with a trapdoor at each end. All burrows were shallow, not reaching deep into the sandy soil but running just below its surface; a few were built in agglomerations of soil on the surfaces of natural rock and concrete ( Fig. 11 A–B). These resemble burrows of species in Monodontium Kulczyński and Rhianodes Raven (Barychelidae) but are much larger than the former and longer (up to 8 cm long, with trapdoors much further apart) than the latter. Trapdoors of adult males (all matured in captivity) were 1.2–1.6 cm long and 1.5–1.9 cm wide; the largest trapdoor of a female (in situ) was 1.7 cm long and 1.9 cm wide.

Males (collected in July 2011) became mature in September and October 2011 (the first one only two months after capture), in September and November 2012, and at the beginning of January 2013. One large female moulted in captivity in September 2011 and again in November 2012. In captivity one spider (which did not build a burrow) was observed to moult in a dorsum-up position and, as soon as completely free from the exuvia, to turn and lie on its back for hardening the new cuticle. Adult males and large females display the same aggressive defence behaviour ( Fig. 6 D) as those of P. i rineae sp. n.

Figures

FIGURE 5. Prothemenops khirikhan sp. n., male holotype (A, D – J) and female allotype (B – C). A – B, habitus, dorsal view. C, labium and palpal coxae, ventral view. D, eye group, dorsal view. E, distal part of right palp, retroventral view. F, same, retrodorsal view. G, same, ventral view. H, same, proventral view. I, tibia and metatarsus of right leg I, ventral view. J, tibia and metatarsus of right leg II, ventral view.

FIGURE 6. Prothemenops khirikhan sp. n. A, habitus of male. B – D, habitus of two females (C – D, dark-coloured form; D, in defence posture).

FIGURE 7. Prothemenops khirikhan sp. n. A, right palpal organ of male holotype, retrolateral view. B, same, ventral view. C – E, vulvae of three female paratypes (C = allotype), dorsal view. Abbreviation: pa = para-embolic apophysis. Scale lines 0.5 mm.

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.