Liphistius metopiae Schwendinger

Schwendinger, Peter J., Huber, Siegfried, Lehmann-Graber, Christina, Ono, Hirotsugu, Aung, Mu Mu & Hongpadharakiree, Komsan, 2022, A taxonomic revision of the Liphistius birmanicus-group (Araneae: Liphistiidae) with the description of five new species, Revue suisse de Zoologie 129 (2), pp. 375-424 : 382-389

publication ID	https://doi.org/ 10.35929/RSZ.0083
DOI	https://doi.org/10.5281/zenodo.7761505
persistent identifier	https://treatment.plazi.org/id/03E18D71-724E-0366-B2EF-FE49529CF913
treatment provided by	Valdenar
scientific name	Liphistius metopiae Schwendinger
status	sp. nov.

Treatment

Liphistius metopiae Schwendinger , sp. nov.

Figs 1 View Fig , 6-7 View Fig View Fig

Liphistius sp. : Schwendinger & Pape, 2000: 353, figs 4-5 (report on predation by fly).

Holotype: MHNG-ARTO-0028249; male (matured 17.VII.1998; right tarsus IV, and to a lesser extent also right tarsus III, bent due to deformation in final moult); Thailand, Mae Hong Son Province and District, near

Pang Tong Palace (19°30’10”N, 97°56’56”E), 870 m; 27.XII.1997; leg. P.J. Schwendinger.

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Paratypes: MHNG-ARTO-0028250 ; 1 male (matured 7.VII.1998); collected together with the holotype. – MHNG-ARTO-0028251 , MHNG-ARTO-0028265 , MHNG-ARTO-0028266 ; 3 females (allotype, MHNGARTO-0028251 ); same locality; 2.XII.1998; leg. P.J. Schwendinger. – MHNG-ARTO-28252 ; 1 female; same locality; 21.X.2000; leg. P.J. Schwendinger. – THNHM; 1 female; same locality; 21.X.2000; leg. P.J. Schwendinger.

Etymology: The species epithet is a name in the genitive case referring to the sarcophagid fly Metopia

sinensis Pape, 1986 whose larvae were observed devouring a female of the new species ( Schwendinger & Pape, 2000).

Diagnosis: Medium-sized species with annulated legs and palps in females and juveniles. Similar to L. lahu , males distinguished by a relatively deeper tibial apophysis (depth/length ratio ~ 2.2 versus ~ 1.4 in L. lahu ; Fig. 6O View Fig cf. Fig. 4F View Fig ), by a more pronounced retrolateral-proximal heel on paracymbium ( Fig. 6J View Fig , L-N cf. Fig. 4 View Fig H-J), by prolateral part of distal edge of the contrategulum more distinctly elevated (indistinctly elevated in L. lahu ; Fig. 6 View Fig H-I cf. Fig. 4E, G View Fig ), and by short para-embolic plate and retroventral edge of embolus complex separated by a very shallow invagination ( Fig. 6 View Fig F-H; no invagination in L. lahu , Fig. 4 View Fig C-E). Females distinguished from those of L. lahu by ventral side of poreplates carrying distinct anterolateral processes and by a smaller receptacular cluster ( Fig. 7 View Fig cf. Fig. 5 View Fig ).

Description of male (holotype): Colour in alcohol (darker in life): Mostly light brown, with some lighter spots on patellae and tibiae of legs and palps (remnants of median and distal annulation). Some light spots also on opisthosomal tergites III-X; on tergites VI-VII most of median portion very light, with only a few dark spots. Most of ventral surface of leg femora and of palpal tibia very light. Palpal tarsus, sclerites of palpal organ and cheliceral fangs dark reddish brown. Most of ventral side of palpal coxae and proximal portion of proximal cheliceral article cream-coloured. Opisthosomal membranes very light brown, speckled with dark brown. Eye mound very dark.

Setae on carapace: A few setae remote from margin; none anterior to fovea.

Cheliceral teeth: 12 and 13 (including a tiny one) small teeth of different sizes on promargin of right and left cheliceral groove, respectively.

Scopula: Distally divided by a short glabrous longitudinal stripe and proximally with a median row of stiff bristles on all tarsi; quite thin and not clearly outlined in distal 3/4 of ventral side of leg tarsi I-II; dense and clearly outlined, covering 4/5 of ventral side of tarsi III-IV.

Tarsal claws: Paired claws with 3-4 teeth on tarsus I, 4 teeth on tarsi II-III, 4-5 teeth on tarsus IV; unpaired claw of tarsi II-III with 0-1 denticle, of tarsi I and IV without denticle.

Palp: Tibial apophysis basally wide in ventral view ( Fig. 6K View Fig ) and deep in retrolateral view (depth/length ratio ~ 2.2, Fig. 6O View Fig ), not set back from distal margin of tibia ( Fig. 6K View Fig ), carrying four apical megaspines with tapering tips, the ventral two longer than the dorsal two ( Fig. 6K, O View Fig ). Distal margin of tarsus widely but shallowly invaginated ( Fig. 6I View Fig ). Paracymbium short, wider than long in ventral view, moderately deep, with an almost flat distal surface and a pronounced, narrowly arched retrolateralproximal heel ( Fig. 6J, M View Fig ); indistinctly elevated cumulus carrying a group of 4-5 long strong bristles ( Fig. 6J, M View Fig ). Subtegulum with an indistinct apophysis ( Fig. 6J View Fig , see also Fig. 6L View Fig for paratype). Tegulum wide, with long and strongly bent, coarsely serrate proximal edge and with a long transverse median ridge; distal margin not elevated ( Fig. 6 View Fig E-F). Pigmented bridge between tegulum and contrategulum on retrodorsal side of palpal organ narrow ( Fig. 6E View Fig ). Contrategulum with short, quite wide proventral process ending in a narrow, truncate apex (Fig. ◄ 6A, D); with several wrinkles on dorsal surface ( Fig. 6I View Fig ) and with a distinct proximal ledge on retrodorsal side ( Fig. 6A, D View Fig ); distal edge of contrategulum quite wide and widely arched, its prolateral part distinctly elevated into a keel ( Fig. 6 View Fig H-I), its dorsal apex narrowly rounded ( Fig. 6A, D View Fig ). Para-embolic plate short and widely arched, separated from keel-shaped retroventral edge of embolus complex by an indistinct invagination ( Fig. 6 View Fig F-H). Embolus proper with sclerotised part strengthened by 3-4 longitudinal ribs reaching apex and carrying tiny denticles distally ( Fig. 6A View Fig , E-J); membranous part of embolus proper distinctly shorter than sclerotised part, both narrowly divided; at base of membranous embolus part a short weakly pigmented area with numerous (distinctly more than in L. lahu ) longitudinal wrinkles and with a widely and asymmetrically angular distal margin ( Fig. 6I View Fig ); embolic folds (connecting membranous and sclerotised parts of embolus proper) short and indistinct ( Fig. 6A, I View Fig ).

Measurements: Total length 14.68; CL 6.03, CW 5.44; opisthosoma 6.27 long, 3.89 wide; eye mound 0.81 long, 1.01 wide; palpal coxa 1.90 long, 1.35 wide; labium 0.60 long, 1.15 wide; sternum 2.90 long, 1.75 wide (0.95 on ventral surface); palp 10.60 long (3.17 + 1.83 + 3.77 + 1.83); leg I 17.73 long (5.00 + 2.38 + 3.81 + 4.40 + 2.14); leg II 19.13 long (5.16 + 2.38 + 3.97 + 5.16 + 2.46); leg III 20.76 long (5.24 + 2.42 + 4.21 + 6.19 + 2.70); leg IV 27.47 long (6.55 + 2.66 + 5.56 + 8.89 + 3.81).

Description of female (allotype): Colour in alcohol (distinctly darker in life): Mostly light brown. Eye mound very dark. Chelicerae brown distally, creamcoloured proximally. Carapace with dark pattern including torch-shaped marking between eye mound and fovea. Palpal coxae only slightly lighter than leg coxae (in contrast to males); labium and sternum distinctly lighter than leg coxae. Legs light brown, with indistinct dark annulations proximally and subdistally on tibiae of legs and palps; tarsi I-II uniformly brown, tarsi III-IV with a light median zone. Membranous cuticle of opisthosoma light greyish brown with dark spots; tergites I-II uniformly brown, the following tergites with increasingly larger light areas, on tergites V-X brown areas reduced to lateral marks.

Setae on carapace: Few (only slightly more than in males) short, blunt setae on posterior and lateral margins and on coxal elevations of carapace; 10 setae in two parallel rows anterior to fovea.

Cheliceral teeth: 12 strong teeth on promargin of each cheliceral groove.

Claws: Palpal claws with 2 and 4 indistinct denticles. Paired tarsal claws of all legs with 3 teeth; unpaired claws of legs I-II with 1 denticle, none on legs III-IV (left tarsus IV missing). All tarsi without scopula.

Vulva ( Fig. 7 View Fig A-C): Uterus externus not examined; presumably small lateral pockets present. Vulval plate slightly wider than long, its lateral folds well developed, carrying several hairs. Anterior margin of poreplate with a quite large pair of arched lobes separated by a deep U-shaped invagination; lateral margins of poreplate ventrally with a knob-shaped anterolateral process on each side; posterior margins of poreplate distinctly bulged; CDO moderately developed, situated slightly posterior to centre of poreplate; receptacular cluster racemose, longer than wide, not reaching anterior margin of poreplate. Posterior stalk relatively short, axe-bladeshaped, clearly narrower than poreplate.

Measurements: Total length 20.99; CL 7.82, CW 6.73; opisthosoma 9.41 long, 7.82 wide; eye mound 1.04 long, 1.23 wide; palpal coxa 2.67 long, 1.78 wide; labium 0.89 long, 1.88 wide; sternum 3.86 long, 2.38 wide (1.48 on ventral surface); palp 12.83 long (4.16 + 2.38 + 3.22 + 3.07); leg I 15.54 long (4.75 + 2.67 + 3.27 + 3.27 + 1.58); leg II 16.48 long (5.05 + 2.77 + 3.37 + 3.61 + 1.68); leg III 18.02 long (5.10 + 2.92 + 3.56 + 4.36 + 2.08); leg IV 24.70 long (6.63 + 3.27 + 4.90 + 7.13 + 2.77).

Variation: For carapace measurements and prefoveal setae counts see Table 1 View Table 1 . In all specimens examined the AME are well developed. In both males examined extent and density of the scopulae are the same. Variation in the shape of the dorsal apex of the distal contrategular edge and of the proventral contrategular process is shown in Fig. 6 View Fig A-D; variation in the shape of the paracymbium in Fig. 6J View Fig , L-N. The male paratype has two long transverse median ridges on the tegulum, the holotype has only one ( Fig. 6E View Fig ). The holotype has one of the ventral bristles on the palpal tarsus distinctly stronger than the other bristles there ( Fig. 6J View Fig ); in the paratype two of these bristles are strengthened ( Fig. 6L View Fig ). The pigmented area at the base of the membranous part of the embolus has either a widely and obliquely truncate distal margin, giving the area an upside-down panflute-like shape, or its distal margin is widely and obliquely angular, like an asymmetrical roof ( Fig. 6I View Fig ). Females have more or less distinctly annulated legs and palps. In two of the females the dark pattern on the pars cephalica of the carapace is less distinct than in the other three females examined. Variation in the shape of the vulval plate is shown in Fig. 7 View Fig . Intraspecific variation in the shape of the vulval plates (particularly concerning anterior lobes and posterior stalk) is considerable, but all females examined possess distinct anterolateral processes, which clearly distinguish them from females of the closely related L. lahu .

Relationships: Liphistius metopiae sp. nov. is morphologically similar and geographically close to L. lahu , which occurs about 130 km to the northeast ( Fig. 1 View Fig ). Looking only at male genital characters, both species are difficult to distinguish, but the differences in female genital characters are more obvious. Both species appear to be most closely related to each other.

Distribution: The new species is only known from

its type locality in Mae Hong Son Province, northern Thailand ( Fig. 1 View Fig ). Since this is only 6-7 km away from the Thailand-Myanmar border, it is quite likely that L. metopiae sp. nov. also occurs in Myanmar.

Biology: Most small burrows (inhabited by juveniles) are T-shaped and equipped with two trapdoors; most large burrows are simple and have only one trapdoor. The largest door (of a female; n=7) observed in the field was 2.2 cm long and 3.2 cm wide; the front doors of the two males examined were 1.2-1.4 cm long and 1.8- 2.0 cm wide. In the field many doors had moss growing on them. There were up to eight signal lines attached to the front entrance of the burrows; the longest line measured 6.5 cm. Four fresh egg cases, 2.1-2.8 cm long, 2.1-3.2 cm wide, 1.4-2.0 cm high, were collected in early and late December; an additional egg case (2.8, 3.0, 2.0 cm respectively) was constructed in captivity in early January. The cases contained 80, 113, 180, 210, 231 and 231 eggs suspended on a fine sheet of thin silken treads. In captivity the two males examined matured in early and late July, about half a year after being collected. In early December several females had egg cases in their burrows in the field. Females moulted between February and June.

Three females have pitlike bitemarks on the carapace and on the proximal part of the chelicerae. These were most likely caused by parasitic mites of the genus Ljunghia Oudemans, 1932 (see Halliday & Juvara-Bals, 2016).

Sarcophagid flies of the species Metopia sinensis raised from L. lahu carcasses in burrows at the type locality were initially interpreted as a case of carrion feeding ( Schwendinger, 1998: 19). Later Schwendinger & Pape (2000) reported about empty puparia in burrows of L. metopiae sp. nov. (then already recognized as being different from L. lahu ) and about six M. sinensis larvae that were slowly devouring a fully active female at the Pang Tong site. This predatory interaction between Liphistius and M. sinensis appears to be a rather widespread (but not common) phenomenon in northern Thailand. Circumstantial evidence indicates that larvae of this fly also feed on L. bristowei ( Bristowe, 1976: 5; Schwendinger, 1990: 339; Schwendinger & Pape, 2000: 355). To our knowledge, this has not been observed for other Liphistius species.