﻿Seven new species of the segmented spider genus Liphistius (Mesothelae, Liphistiidae) in Thailand and Myanmar

﻿Abstract Seven new species of the primitive segmented spider genus Liphistius are described and assigned to species groups based on characters of the male palp and vulva plate. The bristowei group includes L.dawei Sivayyapram & Warrit, sp. nov. (♂♀) from southeastern Myanmar, L.choosaki Sivayyapram & Warrit, sp. nov. (♀) from northwestern Thailand, and L.lansak Sivayyapram & Warrit, sp. nov. (♀) from western Thailand; the trang group (Complex A) contains L.kaengkhoi Sivayyapram & Warrit, sp. nov. (♂♀), L.hintung Sivayyapram & Warrit, sp. nov. (♂♀), L.buyphradi Sivayyapram & Warrit, sp. nov. (♂♀), and L.champakpheaw Sivayyapram & Warrit, sp. nov. (♂♀) from central Thailand.


Introduction
Liphistius is the sole genus of the family Liphistiidae (World Spider Catalog 2023), which, with its sister taxon Heptathelidae, comprises the suborder Mesothelae or segmented spiders, the most basal clade of living spiders (Platnick and Gertsch 1976).Liphistius retains several characters that are plesiomorphic among spiders, such as presence of abdominal tergites and placement of the spinnerets on the ventral median area of the abdomen (Selden 1996;Xu et al. 2015b;Selden and Ren 2017;Xu et al. 2021).All Liphistius species are endemic to Southeast Asia (Indonesia, Laos, Malaysia, Myanmar, Thailand) (World Spider Catalog 2023) except for Liphistius nabang Yu, F. Zhang & J. X.Zhang, 2021 which has been reported from Yunan, in southwestern China (Yu et al. 2021).Currently, 70 Liphistius species are recognized and can be classified into seven species groups based on male and female genitalia: the batuensis group, birmanicus group, bristowei group, linang group, malayanus group, trang group, and tioman group (Schwendinger 1990(Schwendinger , 2017;;World Spider Catalog 2023).Here, we describe seven new Liphistius species from specimens deposited at the Chulalongkorn University Natural History Museum (CUMZ), Bangkok, Thailand.

Materials and methods
A total of 138 Liphistius specimens (104 specimens of 29 previously described species and 34 specimens of new species described here) stored in the Museum were examined and dissected for their genitalia under a Zeiss Stemi DV4 stereomicroscope.The specimens were collected between 2017-2021.The male genitalia were examined from the left palp while the vulvae were dissected from the body and cleared by digesting soft tissue using 3M potassium hydroxide.The terminology of the genital characters follows (Schwendinger and Ono 2011;Schwendinger 2017;Schwendinger et al. 2019Schwendinger et al. , 2022)).All measurements are reported in millimeters.The spider's body lengths do not include the chelicerae or anal tubercle.Palp and legs measurements are given in the following format: total length (femur + patella + tibia + metatarsus + tarsus).The specimens were photographed using a Canon EOS 70D DSLR camera attached to a Stackshot Macro Rail (Cognisys Inc., USA).A Canon EF 100mm f/2.8LMacro IS USM lens was attached to the camera for shooting the spider dorsal and lateral habitus.A Laowa 25mm F 2.8 2.5X-5X Macro lens was attached to the camera for shooting the spider genitalia.The photos were recorded in raw file (.CR2) then convert into TIFF file (.tiff) using Canon Digital Professional 4. Multiple digital photos were combined by the focus stacking technique using Zerene Stacker v. 1.04 (Zerene Systems LLC, USA).The stacked photos were developed (combining and removing background) and labelled in Adobe Photoshop and Adobe Illustrator programs.For species identification, the spider morphologies and genitalia were compared with the original descriptions of previously described species.To protect Liphistius nesting sites from poaching, the species specific collecting sites and their GPS coordinates are not presented in this article.For more specific information, please contact VS or NW directly.Thai specimens are deposited at CUMZ and the Myanmar specimens will be deposited in the Biodiversity Research Centre of Myanmar which is under construction at the site of the Forest Department, Ministry of Natural Resources and Environmental Conservation at Yezin, Nay Pyi Taw.Diagnosis.Liphistius can be distinguished from the heptathelid genera by the male palp possessing a tibial apophysis; the vulva modified into a pore plate or plate-like spermatheca; and the nest structure equipped with signal lines, unique silk lines radiating from the burrow entrance (Platnick and Sedgwick 1984;Xu et al. 2015a).

Liphistius dawei
Palp (Fig. 3A-D): tibial apophysis short, truncate, carrying four black tapering megaspines; cumulus distinctly elevated, bearing long black bristles; paracymbium long, narrow, dark patch with spicules partially isolated by a pale band; subtegulum with moderated apophysis, not enlarged at the tip; contrategulum without apophysis, distal edge of contrategulum arched, leading to conical apex; tegulum kidney-shaped, wider than long, proximal margin convex with finely dentate edge, distal margin slightly concave with round and pronounced apophysis; pigmental bridge between contrategulum and tegulum indistinct; paraembolic plate indistinct, not projecting into a scale-like plate, sclerotized part of the embolus with two longitudinal ridges reaching to the tip.
Vulva (Fig. 3E, F): vulva plate hexagonal, genital atrium with folded lateral margins, carrying lateral hairs; posterior stalk axe-blade shaped, constricted at the based, posterior margin convex; pore plate rectangular and wider than long, lateral margin thickened and projecting into a lips, more distinct on anterior portion, posterior corner slightly projecting, anterior margin thickened and projecting into a lip, slightly arched; receptacular cluster racemose, longer than wide; central dorsal opening wide longer than wide.
Vulva (Fig. 4B, C): vulva plate hexagonal, genital atrium with folded lateral margins, carrying lateral hairs; posterior stalk very wide, M-shaped posterior margin; pore plate rectangular, wider than long, lateral margin convex, anterior margin almost straight, all margins thickened and projected into a lip; receptacular cluster racemose, longer than wide; central dorsal opening wide longer than wide.
Measurements:  Diagnosis.Liphistius lansak sp.nov. is a small Liphistius species recognized by the unique vulva: pore plate with receptacular cluster flanked by a pair of large vesicles.
Description.Male.Unknown.Female (Holotype: ARA-2021-067; Fig. 5A, B).Coloration (in alcohol): carapace pale brown with black marking on the cephalic region and the margin of the thoracic region; abdominal tergites pale brown, with black marking on the anterior and lateral margins of each plate; membranous part of the opisthosoma cream colored with thin mottled black marking; chelicerae dark brown, with black marking, except on the proximal part; palp and legs pale brown, with black annulations on the proximal and distal part of each joint (Fig. 5B).
Vulva (Fig. 5C, D): vulva plate hexagonal, wider than long, genital atrium without lateral hair; posterior stalk short but wide, posterior margin W-shaped; pore plate rectangular, wider than long, lateral margin not projected into a lip, anterior margin invaginated, thickened and projected into a lip; receptacular cluster racemose, as long as wide, flanked by a pair of large vesicles; central dorsal opening round and wide.
Distribution.Known only from the type locality.
Comment.This new species name was mentioned as Liphistius sp.HKK in Sivayyapram et al. (2023).D, 9A-D).The female L. kaengkhoi sp.nov. is difficult to distinguish from those of the L. buyphradi sp.nov., L. champakpheaw sp.nov., L. hintung sp.nov., and L. suwat Schwendinger, 1996.Molecular phylogeny and species delimitation using COI and multi-locus data support monophyly and species status of all new species described here (Sivayyapram et al. 2023).
Palp (Fig. 7A-D): tibial apophysis large, carrying one long slender and three tapering megaspines; paracymbium short, almost round, dark patch with spicules isolated by a pale band; cumulus plain, bearing thin black bristles; subtegulum without apophysis; contrategulum without apophysis, distal edge of contrategulum long, slightly invaginate leading to the conical apex; tegulum large, axe-blade shaped, indistinctly separated from the contrategulum by corrugated surface, proximal margin with a short moderate dentate edge, distal margin almost straight, with round apophysis; pigmental bridge between tegulum and contrategulum sigmoid in shape; paraembolic plate projecting to a scale-liked plate, basally wide, leading into short triangular distal margin; embolus proper: sclerotized part with two longitudinal ridges reaching to the truncated apex.
Measurements Female (Allotype: ARA-2018-286; Fig. 6C, D).Coloration (in alcohol): carapace orange with thick black band on the anterior margin and black mottled marking in the posterior portion of the cephalic region and the thoracic region; abdominal tergites cream colored with large mottled black markings; membranous part of the opisthosoma cream with black mottled marking; chelicerae orange; palp and legs: femur to tibia orange, tarsi and metatarsi of legs I-III black, metatarsi of leg IV orange with black annulation on the proximal and distal area.
Vulva (Fig. 7E, F): vulva plate almost round, genital atrium without lateral hair; posterior stalk short, V-shaped; pore plate rectangular, lateral margins thickened and project into lips, anterior margin convex, less thicken, not project into a lip; receptacular clusters racemose, grape-like in shape; central dorsal opening wide.
Etymology.The specific epithet kaengkhoi refers to Kaeng Khoi District, the type locality of the new species in Saraburi, Thailand.
Distribution.Known only from the type locality.
Comment.This new species name was mentioned as Liphistius sp.CK in Sivayyapram et al. (2023).Diagnosis.Liphistius hintung sp.nov. is similar to L. kaengkhoi sp.nov., L. buyphradi sp.nov., L. champakpheaw sp.nov., and L. suwat in its general appearance.Liphistius hintung sp.nov. is closely similar to L. kaengkhoi sp.nov.but can be distinguished by the male palp: tegulum with coarser proximal dental edge and longer paraembolic plate (Figs 7A-D, 9A-D).The female L. hintung sp.nov. is difficult to distinguish from those of the L. kaengkhoi sp.nov., L. buyphradi sp.nov., L. champakpheaw sp.nov., and L. suwat Schwendinger, 1996.Molecular phylogeny and species delimitation using COI and multi-locus data support monophyly and species status of all new species described here (Sivayyapram et al. 2023).Description.Male (Holotype: ARA-2018-299; Fig. 8A, B).Coloration (in alcohol): carapace pale brown, with black stripe along the lateral and posterior margins; abdominal tergites almost black, paler on the posterior ones; membranous part of the opisthosoma cream in color with black mottled spots; chelicerae olive green, paler at the proximal part; palp and legs uniformly brown.
Palp (Fig. 9A-D): tibial apophysis pronounce, carrying one long slender and three tapering megaspines; paracymbium conical, dark patch with spicules isolated by a pale band; cumulus plain, bearing some bristles; subtegulum without apophysis; contrategulum without apophysis, distal edge of contrategulum long and thick, slightly concave leading to the blunt apex; tegulum large, indistinctly separated from the contrategulum, axe-blade shaped, proximal margin with moderate long, coarsely dentate edge, distal margin oblique with large apophysis; pigmental bridge between the tegulum and contrategulum distinct; paraembolic plate projected into scale-like plate, basally wide with long and pointed distal edge; embolus proper: sclerotized part with two longitudinal ridges running to the truncate apex.
Female (Allotype: ARA-2018-296; Fig. 8C, D).Coloration (in alcohol): carapace orange, with black marking behind the ocular tubercle running to the fovea and coxal elevations and black stripe along the carapace margins, thicker on the anterior margin; abdominal tergites pale brown with large black marking; membranous part of the opisthosoma cream colored with mottled black spots; palp and legs orange with black annulations on the metatarsus and tarsus.
Vulva (Fig. 9E, F): vulva plate hexagonal; genital atrium with a few hairs; posterior stalk trapezoidal, wider anteriorly; pore plate almost square, lateral margins thickened and projected into a lip, bearing indistinct anterolateral lobes; anterior margin convex, less thicken and not project into a lip; receptacular clusters racemose, longer than wide; central dorsal opening wide, longer than wide.
Etymology.The specific epithet hintung refers to Hintung District, the type locality of the new species in Nakhon Nayok, Thailand.
Distribution.Known only from the type locality.Diagnosis.Liphistius buyphradi sp.nov. is similar to L. kaengkhoi sp.nov., L. champakpheaw sp.nov., L. hintung sp.nov.and L. suwat in its general appearance.The male of L. buyphradi sp.nov.can be distinguished from those species, except for L. champakpheaw sp.nov., by the male palp with flat paracymbium (Fig. 14; Schwendinger 1996: fig.43A); and from L. champakpheaw sp.nov.by the male palp with proximal edge of the tegulum moderately long, arched, and finely dentate (short, oblique in L. champakpheaw sp.nov.; Fig. 13C).The female L. buyphradi sp.nov. is difficult to distinguish from those of the L. kaengkhoi sp.nov., L. champakpheaw sp.nov., L. hintung sp.nov.and L. suwat Schwendinger, 1996.Molecular phylogeny and species delimitation using COI and multi-locus data support monophyly and species status of all new species described here (Sivayyapram et al. 2023).Description.Male (Holotype: ARA-2017-139; Fig. 10A, B).Coloration (in alcohol): carapace brown with black stripe along the margins; abdominal tergite olive green, except on the white posterior margins; membranous parts of the opisthosoma cream colored with black mottled spots; chelicerae olive green, paler on the proximal part; palp and legs olive green, without distinct annulation.
Palp (Fig. 11A-D): tibial apophysis round, carrying one long slender and three tapering megaspines; paracymbium round but flat, dark patch with spicules isolated by a pale band; cumulus plane, bearing long black bristles; subtegulum without apophysis; contrategulum without apophysis, distal edge of contrategulum narrow with a depression leading to the oblique conical dorsal apex; tegulum large, axe-blade shaped, possessing a long ridge on the surface, indistinctly separated from the contrategulum, proximal margin with arched, moderately dentate edge, distal margin oblique with moderately apophysis; pigmental bridge between tegulum and contrategulum distinct; paraembolic plate round, as long as wide, project into scale like-plate; embolus proper: sclerotized part with two longitudinal ridges reaching to the tip.
Female (Allotype: ARA-2017-140; Fig. 10C, D).Coloration (in alcohol): carapace orange with black marking behind the ocular tubercle and on the peripheral area of the thoracic region; abdominal tergites black, except on the white posterior margins; membranous part of the opisthosoma cream colored with black mottled spots; chelicerae orange, paler at the proximal part; palp and leg femora to metatarsi orange, distal part of metatarsi I-III with black mottled marking, tarsi I-III black, tarsi IV orange with black annulations on the proximal and distal parts.
Vulva (Fig. 12E, F): vulva plate almost round; genital atrium with lateral hairs; posterior stalk narrow, V-shaped; pore plate quadrangular slightly wider than long; lateral margins thickened, projected into a lip, bearing moderate anterolateral lobes; anterior margin arched, thickened, not projected into a lip; receptacular cluster racemose; central dorsal opening wide.
Etymology.The specific epithet buyphradi is dedicated to Mr. Phuri Buyphrad for providing information on the type locality of the new species.
Distribution.Known only from the type locality.
Comment.This new species name was mentioned as Liphistius sp.SL in Sivayyapram et al. (2023).Diagnosis.Liphistius champakpheaw sp.nov. is similar to L. kaengkhoi sp.nov., L. hintung sp.nov., L. buyphradi sp.nov., and L. suwat in its general appearance.Liphistius champakpheaw sp.nov. is closely similar to L. buyphradi sp.nov.but can be distinguished by the male palp with tegulum that is short, obliqued, with dentate proximal edge (moderately long, arched in L. buyphradi sp.nov., Fig. 11C).The female L. champakpheaw sp.nov. is difficult to distinguish from those of the L. kaengkhoi sp.nov., L. hintung sp.nov., L. buyphradi sp.nov., and L. suwat Schwendinger, 1996.Molecular phylogeny and species delimitation using COI and multi-locus data support monophyly and species status of all new species described here (Sivayyapram et al. 2023).
Description.Male (Holotype: ARA-2017-146; Fig. 12A, B).Coloration (in alcohol): carapace brown, slightly paler in the central area, without any distinct markings;   abdominal tergites black, except for cream colored spots on the posterior margin; membranous part of the opisthosoma cream colored with black mottled spots; chelicerae olive green, paler at the proximal part; palp and legs uniformly brown.
Palp (Fig. 13A-D): tibial apophysis wide distally, carrying four tapering megaspines; paracymbium round but flat, dark patch with spicules isolated by a pale band; cumulus plain, bearing several long bristles; subtegulum without apophysis; contrategulum without apophysis, distal edge of the contrategulum long with slight concavity leading to the truncate apex; tegulum moderate, proximal margins with short, tooth-like coarsely dentate edge; distal margin oblique, with large apophysis; paraembolic plate projected into scale-like plate, large, basally wide, running to blunt distal margin; embolus proper: sclerotized part with two longitudinal ridges reaching to the tip.
Female (Allotype: ARA-2017-146a; Fig. 12C, D).Coloration (in alcohol): carapace orange with black markings on the coxal elevations and the carapace margins; abdominal tergites with black markings except for the cream color on the posterior margin; membranous part of the opisthosoma cream colored with mottled black spots; chelicerae orange; palp and legs orange with black annulation on the proximal and distal part of tarsi.
Vulva (Fig. 13E, F): vulva plate triangular, as long as wide; genital atrium with a few hairs and wrinkle posterior margin; posterior stalk U-shape, short but wide; pore plate quadrangular, slightly longer than wide; lateral margins thickened and projected into lips, bearing moderate anterolateral lobe; anterior margin arched, less thickened but not projected into a lip; receptacular cluster racemose longer than wide; central dorsal opening longer than wide.
Etymology.The specific epithet champakpheaw refers to Cham Pak Pheaw subdistrict, the type locality of the new species in Saraburi, Thailand.
Distribution.Known only from the type locality.
Comment.This new species name was mentioned as Liphistius sp.CPP in Sivayyapram et al. (2023).

Discussion
Here we described seven new Liphistius species can be assigned to two species groups, the bristowei group and the trang group, based on the characteristics of male and female genitalia.

The bristowei group
Liphistius dawei sp.nov. is assigned to the bristowei group by the male palp with an elevated cumulus, adjoining the embolus with the sclerotized part bearing two longitudinal ridges reaching to the tip, the paraembolic plate not projected into a scale-like plate, the subtegulum with an apophysis; and the vulva with projected corners of the pore plate.However, the vulva bears a unique posterior stalk constricted at the base which is more similar to the species belonging to the birmanicus group.Liphistius choosaki sp.nov.and L. lansak sp.nov.are also assigned to the bristowei group according to the vulva plate having a wide posterior stalk.The males of the two latter species are unknown.
The trang group Liphistius kaengkhoi sp. nov., L. hintung sp. nov., L. buyphradi sp. nov., and L. champakpheaw sp. nov.are assigned to the trang group based on the characters of a detached embolus, a paraembolic plate projected to scale-like plate, the tegulum with a prominent distal margin, the subtegulum without an apophysis; and the vulva with small central dorsal opening and receptacular clusters.Specifically, all species are attributed to the complex A of the trang group according to the male palp with a plain cumulus, the contrategulum without an apophysis; and the female with an orange carapace and femora, the vulva with a square pore plate, a U-shape posterior stalk, and a racemose receptacular cluster.

Figure 1 .
Figure 1.Map showing the localities of the new Liphistius species described.