A new species of Liphistius from Myanmar and description of the actual male of L.birmanicus Thorell, 1897 (Araneae, Mesothelae, Liphistiidae)

Abstract Five Liphistius Schiödte, 1849 species of the primitively segmented spider family Liphistiidae are currently known from Myanmar. Here, we described a new species, Liphistiuspyinoolwinsp. nov. (♂♀), which was collected from Pyin Oo Lwin, Mandalay Region, Myanmar, diagnosed based on its genital morphology. The specimens (2♂♂, 5♀♀) collected by Walter C. Sedgwick from Pyin Oo Lwin in 1982 were misidentified as L.birmanicus Thorell, 1897 and are treated here as the newly described species. Accordingly, we described the males of L.birmanicus for the first time, redescribed its female, using newly collected specimens from Yadò, Than Taung and Kalekho Atet townships, Kayin State. We also provided information on the variation in genital morphology of both species, and their relationships within the birmanicus-group of species.


Introduction
With its unique morphology, lifestyle (living in underground burrows), and often being regarded as 'living fossils' (Bristowe 1975), the primitively segmented spiders of the family Liphistiidae has fascinated many naturalists and arachnologists for over one and a half centuries, since the first species was discovered by Schiödte (1849). Recently, interest in this lineage has resurged because of its pivotal position in fully understanding the arachnid tree of life (Platnick and Gertsch 1976), and application of molecular data (Xu et al. 2015a). As the sister lineage to all other extant spiders, liphistiids bear many plesiomorphic characters, such as the presence of abdominal tergal plates and the position of the spinnerets on the median area of the ventral opisthosoma (Platnick and Gertsch 1976;Coddington and Levi 1991;Haupt 2003). In this study, we focus on the Liphistius Schiödte, 1849 from Myanmar, an extremely important yet very poorly studied region, because it is the westernmost distribution of liphistiids according to the current records (Thorell 1897;Platnick and Sedgwick 1984;Schwendinger 1990;Aung et al. 2019;Ono and Aung 2020) and because younger mesothele fossils have also been found in the Middle Cretaceous amber forest in northern Myanmar (Wunderlich 2017(Wunderlich , 2019. The genus Liphistius contains 57 nominal species and is limited to Southeast Asia (Indonesia (Sumatra), Laos, Malaysia, Myanmar, and Thailand) (Xu et al. 2015b;World Spider Catalog 2021). Out of 57 species, 32 Liphistius species have been reported from Thailand (World Spider Catalog 2021). Given that Myanmar and Thailand share similar landmass, climate and geological topography, a comparable species diversity is expected for Myanmar. However, only five species (L. birmanicus Thorell, 1897, L. hpruso Aung et al., 2019, L. lordae Platnick & Sedgwick, 1984 Aung et al., 2019, andL. tanakai Ono &Aung, 2020) have been described from Myanmar so far (Fig. 1). This is probably due to the lack of local arachnologists and the difficulty of accessibility to foreign arachnologists. Working on Myanmar Liphistius is thus vital to fully understanding the geographic distribution and species diversity of liphistiids.
In spite of only five described species, the taxonomy of Myanmar Liphistius, including L. birmanicus, seems to be problematic. The female type of L. birmanicus, which was designed as the lectotype by Platnick and Sedgwick (1984), was collected from Yadò Village (Kayin State since 1989, formerly known as Kayah or Karen State), by an Italian explorer, Leonardo Fea, during his expedition to Myanmar between 1885 and 1889, and described by Thorell in 1897. Another specimen, a damaged immature male, recorded by Gravely (1915) from Mawlamyine (formerly Moulmein, Mon State), far south from Yadò, was considered as L. birmanicus (Bristowe 1938), but is still unclear (Schwendinger 1990). In 1984, L. birmanicus was redescribed based on the specimens collected from Pyin Oo Lwin (formerly Maymyo, Mandalay Region) instead from the type locality Yadò (Platnick and Sedgwick 1984). However, we believe that the specimens from Pyin Oo Lwin might not be L. birmanicus. The issue with L. birmanicus should thus be addressed before further studying Myanmar Liphistius species. To resolve the L. birmanicus issue, and to document Liphistius species diversity, which could allow exploring how geological and climatic events may have shaped its biogeographical history and its diversity in Myanmar, we undertook three expeditions to Myanmar in 2018 and 2019. In this study, we describe L. birmanicus males for the first time and redescribe the females based on the female lectotype and newly collected specimens from the type locality. We also diagnose and describe the specimens collected from Pyin Oo Lwin, misidentified as L. birmanicus by Platnick and Sedgwick (1984) and Schwendinger (1990), as a new species.

Specimen collection
All specimens were collected from Pyin Oo Lwin (Mandalay Region), Than Taung and Kalekho Atet townships (Kayin State), Myanmar (Figs 1, 2). They were captured alive and fixed in absolute ethanol. Their right four legs were then removed, preserved in absolute ethanol, and stored at −80 °C for molecular work. The remains of each specimen were preserved in 80% ethanol as vouchers for morphological examination. All type and voucher specimens were deposited at the Centre for Behavioural Ecology and Evolution (CBEE), College of Life Sciences, Hubei University, Wuhan, Hubei Province, China.
Etymology. The species epithet "pyinoolwin" is a toponym referring to the type locality. Remarks. We examined 8 males and 15 females collected from Pyin Oo Lwin by us, as well as 1 male and 4 females collected by W. Sedgwick on 13 July 1982, which were used to redescribe L. birmanicus by Platnick and Sedgwick (1984) and reviewed by Schwendinger (1990). After examined the male and females collected by W. Sedgwick, even though the male palp was distorted (Fig. 4A-C), we can still identify it as the same as the descriptions and illustrations by Platnick and Sedgwick (1984), and the same as the males and females collected by us at Pyin Oo Lwin.
Remarks. Only 4 specimens were collected from Myanmar before 1984, all of them identified as L. birmanicus in the literature. One female and two juvenile specimens were collected from Yadò and Biapò by Leonardo Fea, most likely in the years of 1887-1888 (Fea 1888) during his expedition to Karen Hills or Kayah-Karen Mountains (Bolotov et al. 2019). These 3 specimens were deposited in MCSNG, Italy. The adult female used to be described as L. birmanicus by Thorell in 1897, then redescribed by Pocock (1990), Bristowe (1932), and illustrated by Haupt (1983). Two juvenile specimens were only mentioned in Thorell's description (1897) and have never been mentioned since then. The fourth specimen, an immature male collected from Mawlamyine, was first