Two new species of the primitively segmented spider genus Liphistius Schiödte, 1849 (Mesothelae, Liphistiidae) from Myanmar

Abstract Two Liphistius species of the primitively segmented spider family Liphistiidae, collected from Loikaw (Kayah State) and Pinlaung (Shan State), Myanmar, are diagnosed and described as new to science based on their genital morphology: Liphistius hprusosp. nov. (♀), Liphistius pinlaungsp. nov. (♂♀).


Introduction
The segmented trapdoor spiders of the family Liphistiidae, the sister lineage to all other extant spiders, are at a pivotal position on the arachnid tree of life (Platnick and Gertsch 1976;Xu et al. 2015a). Liphistiids are often regarded as 'living fossils' (Bristowe 1975) since they retain many plesiomorphic characters such as the presence of abdominal tergal plates and the position of the spinnerets on the median area of the opisthosoma (Pocock 1892;Platnick and Gertsch 1976;Haupt 1983Haupt , 2003Coddington and Levi 1991). Two allopatric subfamilies, Liphistiinae Thorell, 1869 andHeptathelinae Kishida, 1923, are distributed in East (China, Japan andVietnam) and South-east (Laos, Malaysia, Myanmar, Indonesia (Sumatra), and Thailand) Asia, respectively (Xu et al. 2015a, b;World Spider Catalog 2019). Liphistiinae contains 55 described species in the single genus, Liphistius Schiödte, 1849: 33 species from Thailand, 16 from peninsular Malaysia, one from both Thailand and peninsular Malaysia, two from Myanmar, one from Laos, one from Indonesia (Sumatra), and one from both Laos and Thailand (World Spider Catalog 2019). Surprisingly, only two species, L. birmanicus Thorell, 1897 and L. lordae Platnick & Sedgwick, 1984, have been reported from Myanmar since the first species was described in 1897 (Thorell 1897; Platnick and Sedgwick 1984;Schwendinger 1990;Xu et al. 2015b), given that its landmass is even larger than Thailand, its climate and geological topography are similar to those of Thailand, and it shares the mountain ranges with Thailand across a 10° latitude range (Fig. 1). Since at least six species in Thailand (L. albipes Schwendinger, 1995, L. bristowei Platnick & Sedgwick, 1984, L. erawan Schwendinger, 1996, L. jarujini Ono, 1988, L. lahu Schwendinger, 1998, and L. maewongensis Sivayyapram et al., 2017 occur very close to its border with Myanmar, one would expect a comparable species diversity also in Myanmar (Fig. 1).
To document species diversity of Liphistius in Myanmar, we carried out two expeditions in East Myanmar in 2018. In this study, we report two new species of Liphistius after having examined the specimens collected from our expeditions in 2018.

Specimen acquisition
All specimens were collected from Loikaw (Kayah State) and Pinlaung (Shan State), Myanmar (Figs 1, 2). They were collected alive and fixed in absolute ethanol if they were adults, and then their right four legs were removed to be stored at −80 °C for molecular work. The rest of each specimen was preserved in 80% ethanol as the voucher for morphological examination.

Morphological examination
Specimens were examined using an Olympic SZX16 Leica stereomicroscope. Genitalia were cleared in boiling KOH for a few minutes to dissolve soft tissues, examined and photographed with an Olympic BX53 or SZX7 compound microscope and a Canon 7D camera. All voucher specimens are deposited at the Centre for Behavioural Ecol- ogy and Evolution (CBEE), College of Life Sciences, Hubei University, Wuhan, Hubei Province, China. Genital anatomical terminology follows Ono (2011) andSchwendinger (2017). All measurements were carried out under a Leica M205 digital microscope and are given in millimetres. Leg and palp measurements are given in the following order: total leg length (femur + patella + tibia + metatarsus + tarsus), total palp length (femur + patella + tibia + tarsus).
Abbreviations used in the text:    Diagnosis. Females of Liphistius hpruso sp. nov. resemble those of L. birmanicus and L. pinlaung sp. nov. by the poreplate with paired anterior lobes and anterolateral lobes, but can be distinguished from those of L. birmanicus and L. pinlaung sp. nov. by the globosely receptacular cluster (Fig. 3D, E), and the smaller anterolateral lobes of the pore plate (Fig. 3D, E); from L. pinlaung sp. nov. by the narrower posterior stalk; from the other Liphistius species by the pore plate with similarly sized anterior lobes and anterolateral lobes, and with the narrow posterior stalk (Fig. 3B-E).
Male. unknown. Entomology. "hpruso" refers to the type locality of this species. Diagnosis. Males of L. pinlaung sp. nov. resemble those of L. birmanicus, L. lordae and L. lahu by the wide paraembolic plate, but can be distinguished from L. birmani cus by the lack of lateral process of paracymbium and by the cumulus with longer and stouter setae (Fig. 4C, D); from L. lordae by the wider tibial apophysis at base (Fig. 4D) and the tegulum with a dentated margin (Fig. 4C, F); from L. lahu by the narrower tegulum (Fig. 4C, F) and smaller paracybium (Fig. 4D, E). Females of L. pinlaung sp. nov. resemble those of L. birmanicus and L. hpruso sp. nov. by the poreplate with two pair of lobes, but can be distinguished from L. birmanicus by the wider posterior stalk, and sphere-shaped receptacular cluster (Fig. 5D-F); from L. hpruso sp. nov. by the wider posterior stalk and larger anterior lobes of the poreplate (Fig. 5A-F); from the other Liphistius by the poreplate with four anterior lobes (Fig. 5D-F).
Entomology. "pinlaung" refers to the type locality of this species. Distribution. Myanmar (Pinlaung Township, Shan State). Variation. Body measurements, see Table 1. The examined female genitalia differ from each other; for the specimen of XUX-2018-169A, the central part of anterior and anterolateral lobes of the pore plate are depressed in the dorsal view (Fig. 5B), whereas the depression is absent in the other two specimens (XUX-2018-167 and 169J); the shape and size of anterior and anterolateral lobes of the pore plate, as well as the shape of anterior margin of the pore plate are rather variable (Fig. 5A-F). The size of the receptacular cluster is also slightly different ( Fig. 5D-F).
Relationships. Liphistius hpruso sp. nov. and L. pinlaung sp. nov. belong to the birmanicus-group that currently contains L. birmanicus, L. lordae and L. lahu based on morphological characters (Schwendinger, 1998). The two new species are closer to L. birmanicus than to L. lordae and L. lahu since their female poreplates possess four anterior lobes (Figs 3B-E; 5D-F).