Prothemenops phanthurat, 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 : 543-549

Prothemenops phanthurat sp. n.

Figures 8–10 , 11 D–E, 12

Material. THAILAND, Phetchaburi Province, Cha-am District, Khao Nang Phanthurat Forest Park , 30 m, secondary forest on limestone hill : male holotype (matured 22.I.2014) , 1 male (matured late VII.2014) and 4 female paratypes; 28.III.2013, leg. K. Hongpadharakiree; sample THKH-12/05. Same locality ; 6 male paratypes (matured 25.I.2014, 26.I.2014, 25.VII.2014, 8.VIII.2014, 12.VIII.2014 and 26.VIII.2014) , 8 female paratypes (one of them the allotype); 11.I.2014; leg. P.J. Schwendinger; sample TH-13- 14 /04. 1 male paratype (THNHM-I-2014- 00005) and 1 female paratype (THNHM-I-2014-00006) deposited in THNHM, all others (without registration numbers) in MHNG.

Etymology. “Nang Phanthurat ” is a female giant in Thai mythology. The species name, a noun in apposition, refers to the type locality (where Nang Phanthurat died and turned into a hill) of this species and not to the size of the spiders examined.

Diagnosis. Distinguished from P. siamensis , P. irineae sp. n. and P. khirikhan sp. n. by both sexes with smaller body size (carapace lengths of males 6.8, 5.1–7.0 and 5.8–7.6 versus 4.1–5.2 in P. phanthurat sp. n.); males with basally very wide retroventral apophysis on palpal tibia, with para-embolic apophysis developed as a crescentshaped crest on posterior side of embolus, and with sigmoid, elongate, subapical spine on prolateral side of tibia I. Further different from P. siamensis by males with tibia I more slender and lacking coupling spurs and megaspines; females with smaller, more globular receptacular bases, receptacular stalks and heads bent dorsad instead of outward, and scopula present on tibia I. Further differs from P. i r i ne a e sp. n. and P. khirikhan sp. n. by males with proximally much wider retroventral apophysis carrying spicules; females with lunate prolateral depression being distinctly lighter in colour than rest of of palpal coxa and with rudimentary scopula on tarsus III. Further different from P. khirikhan sp. n. by females having a scopula on tibia I.

Description. MALE (holotype). Colour in alcohol ( Fig. 8 A; for colouration of live males see Fig. 9 A–B): eye mound with dark pigment around eyes and light areas between most of them; carapace brown, with darker mottling; legs and palps light brown, femora appearing slightly darker due to dense cover of fine grey hairs (this much thinner on other articles); all tarsi pseudosegmented ( Fig. 8 L). Dorsal side of opisthosoma uniformly greybrown in anterior third; posterior two-thirds with six dark transversal bands, first three more or less distinctly connected with each other and with anterior dark area along mid-line, all bands laterally dissolving into dark spots. Ventral side of opisthosoma light brown. Ventral side of whole animal generally paler than dorsal side.

Total length 11.2. Carapace 4.9 long, 4.0 wide, hirsute, densely covered with fine white, adpressed hairs everywhere, especially dense 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 ( Fig. 8 C). Fovea narrow, occupying 6% of carapace width at that point; anterior margin slightly procurved in median portion and recurved at both ends, posterior margin with a distinct median indentation ( Fig. 8 D). Eye group in three rows, 0.75 long, front width 0.62, back width 0.94, occupying about 40% of “head” width, raised on low mound carrying an extra-long sigmoid bristle between AME and ALE. Eye diameters: AME 0.22, ALE 0.30, PME 0.13, PLE 0.34. MOQ 0.43 long, front width 0.50, back width 0.50. Sternum 2.6 long, 2.1 wide; sigilla not discernible (on exuviae of other specimens all sigilla tiny, anterior two marginal, posterior one slightly remote from margin). Labio-sternal suture very short, not interrupted in middle. Labium 0.4 long, 0.8 wide, with two groups of long and bent bristles on anterior margin. Palpal coxae 1.5 long, 0.8 wide; lunate prolateral zone of ventral side slightly sunken and of same colour as rest of article; some bristles in prolateral half of proximal margin clearly shorter than nearby setae. Chelicerae with rastellum sessile, composed of four pointed spines (clearly shorter and thicker than nearby stout bristles, but weaker than in males of other two new species) in one row; cheliceral groove with 7/7 teeth on promargin plus 4/6 tiny denticles in a median row.

Legs 3214; lengths: leg I 16.9 (3.9 + 2.8 + 4.1 + 4.1 + 2.0), leg II 14.9 (3.6 + 2.3 + 3.6 + 3.6 + 1.8), leg III 13.3 (3.0 + 1.9 + 2.9 + 3.7 + 1.8), leg IV 20.1 (5.1 + 2.4 + 5.0 + 5.3 + 2.3). Three light, glabrous, longitudinal stripes on femora of palps and most legs only discernible at base, only the one on retrolateral side of femur IV well developed. Two glabrous dorsal stripes on all patellae and on tibia of palp. Tibia I and metatarsus I straight and unmodified ( Fig. 8 J). Tibia I with two elongate subapical spines on prolateral side, the distal one slightly sigmoid, the more proximal one procurved (such a spine, but never sigmoid, also present in males of P. irineae sp. n. and P. khirikhan sp. n.) ( Fig. 8 I–J). Metatarsi I–II with one indistinct (especially on left leg I) proventral spine and two stronger (especially the more distal one) retroventral spines ( Fig. 8 J–K). Patella III with two parallel rows of six (4+2) short prodorsal spines on right side and with three rows of six spines (1+4+1) on left side. All tibiae and metatarsi with ventral spines, those on posterior legs more numerous and present also on prodorsal and retrodorsal sides. Tarsi I–III aspinose; tarsus IV with one retrolateral spine. 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, very thin in distal two-thirds of tarsus IV; thin in anterior two-thirds of ventral side of metatarsi I–II ( Fig. 8 J–K), very thin in same portion of metatarsus III, absent on metatarsus IV. Paired tarsal claws armed with row of mostly six (6–7 on anterior legs, 5–6 on posteriors) unequal teeth; unpaired claw unarmed.

Palp 6.1 long (2.3 + 1.4 + 1.5 + 0.9). Tibia relatively stout due to moderately long retroventral apophysis with very wide base; retroventral apophysis situated a short distance from distal margin of tibia and carrying several spines of different lengths (apical ones short, one more proximal spine long; Fig. 8 F–G). Short cymbium with rounded lobe prodistally and more angular lobe retrodistally, carrying stiff bristles on distal margin plus clubshaped trichobothria on dorsal surface. Palpal organ with pyriform tegulum, its distal haematodocha vertically divided by an indistinct, broken pigmented stripe and not reaching base of embolus; embolus long, slender and bent away from axis of palp; embolar base narrow, carrying on its posterior side (facing tibia; not on retrolateral side as in other two new species) a para-embolic apophysis in the form of a sharp, crescent-shaped crest; apical portion of embolus thin, flagelliform, flexible; transition between basal and apical portion of embolus continuous, without marked border ( Figs 8 G–H, 10A–C).

Opisthosoma covered with fine, adpressed white hairs (only on dorsal side) and more erect dark bristles of different sizes (everywhere), 4.7 long, 3.4 wide. PMS 0.4 long, PLS 1.8 long: apical article 0.3 (slightly longer than wide), median article 0.6, basal article 0.9 long.

FEMALE (allotype). As in male, except for the following. Carapace with more distinct dark reticulation (especially on pars cephalica); two distinct light areas on both lateral sides of eye group; two dark paramedian bands (separated by light band with indistinct median stripe) on pars cephalica between eye group and fovea ( Fig. 8 B); palpal coxae, labium and sternum slightly darker; sternal sigilla more distinct; lunate prolateral area of palpal coxae clearly paler than rest of article ( Fig. 8 E). Light, glabrous longitudinal stripes on femora of palps and legs much more distinct than in male. See Fig. 8 B for female allotype preserved in alcohol, and Fig. 9 C for colouration of live female paratype.

Total length 13.7. Carapace 4.7 long, 3.6 wide, bristles on its lateral and posterior margins thinner than in males; pars cephalica moderately raised (distinctly more so than in males). Fovea occupying 11% of carapace width at that point, median portion of anterior margin very slightly procurved and both ends recurved, no indentation in posterior margin visible. Eye group 0.65 long, front width 0.58, back width 1.01, occupying 38% of “head” width. MOQ 0.36 long, front width 0.49, back width 0.56. Eye diameters: AME 0.18, ALE 0.25, PME 0.12, PLE 0.31. Sternum 2.5 long, 2.0 wide; sigilla small and marginal, posterior pair slightly larger than others. Labium 0.5 long, 0.9 wide. Palpal coxae 1.9 long, 0.9 wide, carrying 20/21 strong cuspules in proximal-prolateral corner; its lunate prolateral zone slightly sunken and lightly pigmented throughout ( Fig. 8 E). Chelicerae distinctly stronger than in males; rastellum sessile, composed of 10/11 short strong spines in several rows; cheliceral furrows with seven teeth on promargin and 5/6 denticles (larger than in male) in a median row. Legs stronger than in male; lengths: leg I 10.2 (3.0 + 2.2 + 2.2 + 1.8 + 1.0), leg II 8.8 (2.6 + 1.9 + 1.8 + 1.6 + 0.9), leg III 8.1 (2.4 + 1.5 + 1.4 + 1.7 + 1.1), leg IV 12.3 (3.3 + 2.2 + 2.9 + 2.7 + 1.2). Patella III with 6/7 prodorsal spines, dorsal bristles not stronger than in male; prolateral side of femur IV distally with dense group of slightly stronger bristles than in male. Prolateral side of palpal femur and of femur I light-coloured and mostly glabrous, fused with light glabrous prodorsal stripe. Only lower (ventral) half of retrolateral side of femur IV glabrous, fused with retrolateral glabrous stripe but not with retrodorsal one.

Scopula dense on ventral side of tarsi and metatarsi I–II (on metatarsus II proximally absent), thin distally on prolateral side of tibia I, rudimentary on ventral side of tarsus III (only few scopula hairs proximally, distinguished from nearby bristles by being more erect and carrying a bent tip), absent from metatarsus III and from leg IV; scopula dense on 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, three closely spaced distoventral ones on tarsus I; three such on tarsus II; one prodorsal plus 5/6 ventral ones on tarsus III; 4/6 prolateral to retrolateral ones on tarsus IV; two retroventral and one proventral in proximal third, plus two apical spines on metatarsus I; two retroventral, one proventral and three apical spines on metatarsus II; 6/7 prodorsal ones on patella III; spines on other leg articles mostly as in male. Paired tarsal claws with row of four teeth on anterior legs and 4–5 on posterior legs, unpaired claws bare; palpal claw with row of four teeth (proximal and distal ones larger than two medians).

Opisthosoma 7.0 long, 4.7 wide. PMS 0.4 long; PLS 1.6 long: apical article 0.2, median article 0.4, basal article 1.0 long.

Vulva ( Fig. 10 D) with wide, short atrium leading to two widely separated sperm receptacles, each composed of small globular base and tubuliform, dorsad-bent stalk terminating in globular or pyriform, lightly pigmented head of slightly larger size than receptacular base.

Variation. Carapace lengths in eight males (smallest female with egg case to largest female in parentheses; n = 12) range 4.1–5.2 (4.4–6.0), carapace widths 3.4–4.4 (3.3–4.8). All well-preserved females show two conspicuous light areas on both lateral sides of the eye group (see Fig. 8 B). These marks are obscured in poorly preserved females (see corresponding remark in “Material and methods”) and may actually present a diagnostic character. In six male paratypes, all femora are darker (more greyish) and more strongly contrasting with the other articles than in the remaining two males (including the holotype). One female has only the prolateral half of the lunate sunken zone of the palpal coxae clearly pallid; the retrolateral half of that zone is only indistinctly lighter in colour than the rest of the article. One male paratype has strikingly dark brown booklung plates; not so in all other specimens. One male has two (instead of one) sigmoid prolateral-subdistal spines on its left tibia I; another male has none on its right tibia I. The indentation in the posterior margin of the fovea is distinct, indistinct or absent (covered?). All male paratypes have (in addition to short bristles as present in the holotype) one to several peglike cuspules (narrower than the strong cuspules of females) in the proximal-prolateral corner of the palpal coxae. One male has three prolateral to retrolateral spines on the right tarsus IV and one retrolateral spine on the left; four males (including the holotype) have one retroventral spine on each tarsus IV; three males have none. The number of prodorsal spines on patella III of males varies from four to seven, those of females from four to eight. The scopula hairs on tarsus III of females vary from being few and almost indiscernible to being quite numerous and clearly visible (in two largest females). Variation in the shape of the vulva of four females, see Fig. 10 D–G. One female has a large swelling on the right receptacle and a small one on the other ( Fig. 10 E).

Relationships. The absence of coupling spurs on tibia I of males and the dorsad-directed receptacles in females show that P. phanthurat sp. n. is closely related to P. irineae sp. n. and P. khirikhan sp. n. All three species are also in quite close geographical proximity ( Fig. 12 ). The smaller size of both sexes, a modified prolateralsubapical spine on tibia I, apical spines on the tibial apophysis of the palp, and a different kind of para-embolic apophysis in males indicate that P. phanthurat sp. n. is sister to the other two new species.

Distribution. Prothemenops phanthurat sp. n. is only known from the type locality in the southern part of central Thailand ( Fig. 12 , locality 3). It is the most northern of the three new species treated here.

Biology. The spiders examined lived on an isolated, rugged limestone hill on which grows a dry secondary forest. Small and medium-sized spiders were collected from Y-shaped burrows with two trapdoors ( Fig. 11 D), large spiders from unbranched burrows with a single door, all built in loose soil between and below rocks. The front-door of five males (all matured in captivity) was 0.9–1.2 cm long and 1.1–1.3 cm wide, the back-door 0.6–0.9 cm and 0.85–1.0 cm, respectively. The largest measured trapdoor (of a female) was 1.35 cm long and 1.5 cm wide. Some spiders had the upper portion of their burrows (behind the doors) built as 1–2 cm long galleries above ground ( Fig. 11 E). When inspected in early January, a few burrows were empty and had fresh exuviae inside. These burrows were probably abandoned by males that had become adult not long before.

One male (collected in March 2013) became mature in late January 2014; two others became mature almost at the same time as the first one, and these were collected only two weeks earlier. Five other males (collected in 2013 and in 2014) matured from late July to late August 2014. This is a strong indication for two separate reproductive periods per year, as it was observed for the diplurid Phyxioschema suthepium Raven & Schwendinger in northern Thailand ( Raven & Schwendinger 1989: 59–60; Schwendinger 2009: 8). Several females were gravid (eggs shining through the venter of the opisthosoma) when collected in early January, which indicates that they had probably mated in December. The males that matured in January are thus probably latecomers; the first mating period is in December and January. The second mating period is in August, probably extending into September. In captivity three females moulted between early April and late June; one of them again in late September. No display of aggressive defence behaviour could be provoked from any of these spiders.

Four females (collected in early January) built egg sacs in mid- to late February. These were suspended in the deep portion of the burrows and attached to the burrow lining by short, wide bands of silk on two sides ( Fig. 9 D). The mother usually moved past the egg sac on its upper side, occasionally also underneath the lower, bagging side. Two egg sacs (preserved) were about 0.8 cm in diameter and 0.55 high, containing 27– 37 eggs. After a bit over one month white and clumsy second instar juveniles hatched from the egg sacs of two other females. Spiderlings from the first egg sac moulted to the third instar about four weeks later. In late May, 16 of them left the maternal burrow and built their tiny burrows nearby. A single third instar spiderling from the second egg sac was seen in the maternal burrow in late June. March and April are the hottest and driest months of the year at the type locality, not favourable for the dispersal and settlement of trapdoor spiderlings. Thus they remain in the maternal burrow for about two months, until well into the rainy season, when increasing cloud cover reduces the temperatures, and the soil becomes moist and more suitable for burrowing. Offspring from the second mating period presumably hatch and disperse towards the end of the rainy season in September and/or October.

Figures

FIGURE 8. Prothemenops phanthurat sp. n., male holotype (A, C – D, F – L) and female allotype (B, E). A – B, habitus, dorsal view. C, carapace, lateral view. D, fovea, dorsal view. E, labium and palpal coxae, ventral view. F, distal part of right palp, retrodorsal view. G, same, ventral view. H, palpal organ, prolateral view. I, tibia of left leg I, ventral view. J, tibia and metatarsus of right leg I, ventral view. K, tibia and metatarsus of right leg II, ventral view. L, right tarsus I showing pseudosegmentation, prodorsal view.

FIGURE 9. Prothemenops phanthurat sp. n. A, habitus of male holotype (light form). B, habitus of male paratype (dark form). C, habitus of female paratype. D, egg sac suspended inside burrow (in captivity).

FIGURE 10. Prothemenops phanthurat sp. n. A, right palpal organ of male holotype, ventral and slightly proximal view. B, same, retrolateral view. C, same, prolateral view. D – G, vulvae of four female paratypes (D = allotype; E with anomalous swellings on both receptacles), dorsal view. Abbreviation: pa = para-embolic apophysis (here crescent-shaped). Scale lines 0.5 mm (A – C), 0.2 mm (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.