Heptathela nui, Schwendinger & Ono, 2011

Schwendinger, Peter J. & Ono, Hirotsugu, 2011, On two Heptathela species from southern Vietnam, with a discussion of copulatory organs and systematics of the Liphistiidae (Araneae: Mesothelae), Revue suisse de Zoologie 118 (4), pp. 599-637 : 607-611

Heptathela nui sp. n. Figs 21-33, 68

HOLOTYPE: MHNG, without registration number, sample SV-03/21; male (matured 10.VI.2004); Vietnam, Lam Dong Province, Mt Penhatt near Quang Trung Reservoir , about 8 km SW of Da Lat, 11°52’37”N, 108°25’58”E, 1500 m; 6.IX.2003; leg. P. J. Schwendinger.

PARATYPES: MHNG, without registration number, sample SV-03/21; 2 males (matured 3.V.2004, 10.VII.2004) and 3 females (“ allotype ” constructed egg case in XII.2003 and moulted 5. IV.2004); collected together with the holotype. – NSMT-Ar 9618, 9619 (1 male, 1 female), IEBR, without registration numbers (1 male, 1 female) , MHNG, without registration numbers (all other specimens), sample SV-03/22; 3 males (matured early June 2004, 15.VI.2004, 21.IV.2005) and 4 females; Cam Ly Waterfall, western outskirts of Da Lat city, 11°56’37”N, 108°25’14”E, 1450 m; 8.-9.IX.2003; leg. P. J. Schwendinger.

ETYMOLOGY: “Nui”, a noun in apposition, is the Vietnamese word for “mountain”.

DIAGNOSIS: Males of the new species can be distinguished from those of the closely related H. australis by: anterior margin of sternum low; paracymbium stronger, with distinct proximal tubercle; conductor narrower, with more strongly bent apex; tegulum with larger marginal apophysis, terminal apophysis more continuously narrowing towards apex, its dorsal and ventral sides at an acute angle to each other; prolateral side of contrategulum with light-coloured central portion; sharp (outer) distal edge of contrategulum convex, broadly rounded, without beak-like extension; denticles on inner edge of contrategulum running down to ventro-proximal area in a continuous row; embolus shorter, its terminal fringe more coarsely serrate. Females of H. nui sp. n. differ from those of H. australis by: bursa copulatrix shorter, with more strongly inclined lateral margins; receptacular clusters smaller, with more or less distinct stalks, all four sitting on the anterior margin of the bursa copulatrix.

DESCRIPTION: MALE (holotype). Colouration in alcohol (live specimens distinctly darker): Carapace and legs light reddish brown; ocular mound dark; bulbal sclerites and distal part of cymbium red-brown, cymbial projection light brown. No annulation on legs or dark pattern on carapace and opisthosomal tergites. Ventral side of body and limbs generally lighter than dorsal side. Opisthosoma cream, mottled with light grey; tergites uniformly light greyish brown.

Total length 14.4. Carapace 6.3 long, 5.0 wide, set with a few short, peg-like hairs (with blunt tips) on margin (mostly anteriorly and posteriorly), behind ocular mound and on coxal elevations; only few long pointed hairs running over ocular mound in a longitudinal row. Eye group 0.87 long, 0.99 wide anteriorly, 0.91 posteriorly. Eye sizes and interdistances: AME 0.04, ALE 0.60, PME 0.32, PLE 0.50; AME-AME 0.14, AME-ALE 0.07, PME-PME 0.05, PME-PLE 0.08, ALE-PLE 0.06. MOQ 0.43 long, front width 0.21, back width 0.52. Labium 0.5 long, 1.2 wide. Sternum 2.7 long, 2.2 wide (1.3 on ventral surface). Anterior margin of sternum low, thus only a shallow furrow present between sternum and labium. Maxillae 2.2 long, 1.4 wide. Promargin of cheliceral groove with 10 teeth on right chelicera, 12 on left. Paired tarsal claws with 3-5 teeth; unpaired claws without denticles. Measurements of limbs: palp 12.1 (3.6 + 2.1 + 4.1 + 2.3); leg I 19.7 (5.6 + 2.5 + 4.0 + 5.0 + 2.6); leg II 19.3 (5.2 + 2.4 + 3.8 + 5.2 + 2.7); leg III 20.6 (5.0 + 2.5 + 3.8 + 6.2 + 3.1); leg IV 25.9 (6.6 + 2.7 + 4.9 + 8.2 + 3.5). “Tibial spurs” absent on all legs. Opisthosoma 5.6 long, 3.7 wide; posterior margin of genital sternite widely rounded, with an indistinct invagination in the middle (Fig. 21).

Palp (Figs 22-26) with paracymbium carrying a proximal tubercle (Fig. 23); cymbium and paracymbium almost at right angles to each other; distoventral zone of cymbium (below subtegulum) unpigmented and unsclerotised (Fig. 23). Tegulum with a very long, pointed, distad-directed marginal apophysis with a sharp edge (Figs 22-25), and with a retrolaterad- and slightly proximad-directed terminal apophysis continuously narrowing to a rounded, distad-bent apex (Figs 23, 25); dorsal side of terminal apophysis less extended than in H. australis , carrying a weakly dentate edge (Fig. 25) not being in contact with edge on marginal apophysis. Contrategulum with a cream central portion on prolateral side (Fig. 22); two parallel distal edges present: the outer one sharp, the inner one finely dentate (Fig. 23); sharp edge convex, widely rounded, without beak-like extension (Fig. 22); row of denticles on inner edge running down to near ventro-proximal margin of contrategulum and there forming two rows of denticles together with a few irregularly arranged additional denticles situated more proximally (Fig. 23). Conductor situated ventro-proximally on embolus; proximal portion of conductor fairly wide and fused with embolic base; distal portion of conductor free, narrow, blade-like, with slightly hook-like apex (Figs 23-26). Embolus largely sclerotised, prolateral half strengthened by numerous longitudinal ribs (Figs 22, 25); terminal fringe around opening of sperm duct (= spermophore) hyaline, coarsely serrate, with fairly deep indentations (Figs 22-24, 26).

FEMALE (“ allotype ”). Colouration similar to that of male but slightly lighter; palpal tarsi brown.

Total length 21.6. Carapace 8.3 long, 6.3 wide. Eye group 0.97 long, 1.03 wide anteriorly, 1.00 posteriorly. Eye sizes and interdistances: AME 0.06, ALE 0.60, PME 0.35, PLE 0.50; AME-AME 0.19, AME-ALE 0.14, PME-PME 0.04, PME-PLE 0.06, ALE-PLE 0.06. MOQ 0.49 long, front width 0.30, back width 0.52. Labium 1.1 long, 2.0 wide. Sternum 3.6 long, 2.5 wide (1.9 on ventral surface), its anterior margin distinctly elevated, thus separated from labium by a deep suture (not so in males). Maxillae 2.8 long, 1.9 wide. Promargin of cheliceral groove with 11 teeth on each chelicera. Paired tarsal claws of legs with 2-4 teeth, unpaired claws without denticles; each palpal claw with 2 denticles. Measurements of limbs: palp 13.3 (4.5 + 2.5 + 3.0 + 3.3); leg I 15.2 (4.9 + 2.6 + 3.0 + 3.0 + 1.7); leg II 14.6 (4.4 + 2.6 + 2.7 + 3.1 + 1.8); leg III 15.5 (4.3 + 2.7 + 2.7 + 3.8 + 2.0); leg IV 21.9 (6.1 + 3.0 + 3.9 + 6.2 + 2.7). “Tibial spurs” present on legs I-III. Opisthosoma 7.7 long, 6.4 wide. Posterior margin of genital sternite broadly rounded, with a slight median invagination.

Vulva (Fig. 31). Bursa copulatrix short, plano-convex in dorsal and ventral view, its anterior margin widely rounded and carrying four anteriad-directed receptacular clusters on indistinct short stalks, the median pair slightly larger than the lateral one. Genital atrium densely set with fine hairs on dorsal and ventral walls.

VARIATION: Range of measurements in males (n=6) and in females with clearly developed vulvae (n=7; in parentheses) examined: Body length 13.2-16.5 (16.4-22.5), carapace length 5.2-6.5 (6.1-8.2), carapace width 4.2-5.3 (4.9-6.5). For variation in the shape of the vulva in three females, see Figs 31-33. In one female the receptacular clusters are raised on relatively long stalks (Fig. 33), in two other females the stalks are stout and rather indistinct (Figs 31-32). Variation in the shape of the palpal organ is less pronounced than in H. australis : the marginal tegular apophysis carries a subterminal FIGS 21-30

Heptathela nui sp. n., male holotype (21-26) and three male paratypes from Cam Ly Waterfall (27-28; 29; 30). (21) Posterior margin of genital sternite, ventral view. (22) Distal part of left palp, prolateral view. (23) Same , ventral view. (24) Same , retrolateral view. (25) Same , distal view. (26) Embolus and conductor, proventral view. (27) Conductor , proventral view. (28) Marginal and terminal apophysis of tegulum, ventral view. (29) Marginal apophysis of tegulum, ventral view. (30) Outline of paracymbium, ventral view. PT = proximal tubercle of paracymbium; other abbreviations as in Figs 1-15. Scale lines 1.0 mm .

FIGS 31-33

Heptathela nui sp. n., three female paratypes. (31) Vulva of “ allotype ”, dorsal view; dorsal and lateral walls of genital atrium not shown. (32-33) Bursae copulatrices of two other females, dorsal view. Abbreviations as in Figs 16-20. Scale lines 1.0 mm.

denticle in two males (Figs 25, 28), in others it is bare (Fig. 29); the proximal tubercle of the paracymbium is very distinct in two males (Figs 23, 30), less so in others; in some males the scattered denticles below the continuous row of denticles on the ventro-proximal side of the contrategulum are indistinct. In one female the posterior median spinnerets are fused only along their ental sides but the apices are still free, whereas in all other conspecific spiders examined these spinnerets are completely fused.

REMARKS: The paired leg claws of the “ allotype ” are inflated, especially on the posterior legs. This is not so in any of the other specimens of both species examined and thus it was probably caused by preservation. Similar rare cases of inflated claws were also observed in alcohol-preserved specimens of mygalomorph spiders.

RELATIONSHIPS: Heptathela nui sp. n. possesses a vulva similar to that of H. abca from northern Vietnam, and to H. bristowei Gertsch, 1967 , H. sinensis and H. schensiensis ( Schenkel, 1953) from central China. However, strong similarity and several likely synapomorphies in the male palps of H. australis and H. nui sp. n. show that these species are the most closely related. See also Discussion - Systematics.

DISTRIBUTION: Known only from two localities near Da Lat city in southern

Vietnam.

BIOLOGY: The spiders examined were collected from a steam bank in an evergreen hill forest, from the recess of an earth bank at the side of a path in a pine forest (both at Mt Penhatt), and from an earth bank in a park with pine trees (at Cam Ly Waterfall). Burrows were as those of H. australis , but at the Cam Ly site (not so on Mt Penhatt) they all had several grass stems attached to their entrances to enlarge the sensory area. “Twig-lining” is known from individual populations of several species of mygalomorph trapdoor spiders in Australia, North America and Japan (see Haupt, 1995 for a summary), and it was also reported for Ryuthela populations ( Haupt, 1983: 286) and for some H. abca at the type locality ( Ono, 1999: 41, figs 13-14). Trapdoors of females were up to 2.6 cm wide and 2.0 cm long; those of penultimate males 1.6-2.1 and 1.1-1.6 cm, respectively. Large and medium-sized spiders react to disturbance by “tiptoeing”, spreading their chelicerae and raising their palps. One egg case (2.5 cm in diameter and 1.7 cm high) was built on 19.XII.2004. It held 83 light yellow eggs suspended above the bottom of the inner chamber. The female with eggs moulted in early April of the following year; other females moulted in January, March, April, September, October and November, usually twice per year. Males (collected in early September 2003) became adult between May and July 2004 and in April 2005.

The largest female (gravid; died before laying its eggs) had about 50 ectoparasitic mites of the genus Ljunghia on its prosoma. These caused the same kind of scars on the carapace of the spider (Fig. 68) as described earlier in this paper for H. australis .

SPECIES EXAMINED FOR COMPARISON