Ten new species of the spider genus Althepus Thorell, 1898 from Southeast Asia (Araneae, Ochyroceratidae)

Abstract Spiders of the genus Althepus Thorell, 1898 are found throughout Southeast Asia, notable for their long walking legs. Ten new species are reported in this paper from China, Indonesia, Laos and Myanmar: A.chengmenensis Li & Li, sp. n. (♂♀), A.cheni Li & Li, sp. n. (♂♀), A.gouci Li & Li, sp. n. (♂♀), A.hongguangi Li & Li, sp. n. (♂♀), A.phousalao Li & Li, sp. n. (♂♀), A.qianhuang Li & Li, sp. n. (♂♀), A.qingyuani Li & Li, sp. n. (♀), A.sepakuensis Li & Li, sp. n. (♂♀), A.xuae Li & Li, sp. n. (♂♀) and A.yizhuang Li & Li, sp. n. (♂♀). These species were found in cave entrances and among tree-buttresses, indicating the spiders have a preference for dark and moist environments. All types are deposited in the Institute of Zoology, Chinese Academy of Sciences in Beijing, China (IZCAS).

Distribution. China. Known only from the type locality ( Figure 21). Natural history. Collected on rocks outside a cave at an altitude of 2393 m. Etymology. The specific epithet is a patronym in honour of Zhigang Chen who collected the types; noun (name) in genitive case.

Althepus cheni
Diagnosis. Althepus cheni Li & Li, sp. n. can be distinguished from all other known species of the genus by the large, curved, spine with tip directed distally of the palpal tarsus ( Figure 3A) and by the needle-like projection on the distal end of the conductor in males ( Figure 3A, B); females can be distinguished by a large membranous sac extending posteriorly and by two types of spermathecae: six short, curved spermathecae, and one globose spermatheca on a long stalk on each side ( Figure 4A).

Diagnosis.
A. gouci Li & Li, sp. n. can be distinguished from all other known species of the genus by the short embolus and by the hook-like projection on the widened conductor in males ( Figure 5); females have two types of spermathecae: one spermatheca with 5-6 curved, long branches, and 5-6 short, thick spermathecae, on each side (two spermathecae with stalks on the left side and four spermathecae with stalks on the right side) ( Figure 6A).
Description. Male (holotype). Total length 3.44; carapace 1.10 length, 1.15 width; abdomen 1.90 length, 0.88 width. Carapace round, yellow, with brown lateral margins and one wide, brown median band, the middle one wider than the others ( Figure 6C). Anterior margin of cephalic region distinctly elevated. Clypeus lightbrown. Cheliceral promargin with two teeth, followed by a lamina, retromargin with two small teeth ( Figure 20C), posterior surface of fang with 18 small denticles. Labium brown. Sternum yellow, with some small brown spots. Abdomen elongate, with complex patterns dorsally and ventrally ( Figure 6C). Legs all missing. Male palp ( Figure  5A-D): tarsus with three slightly curved, serrated bristles at the top of the cymbial protrusion (one of them was missing, Figure 5A), and one hooked spine with the tip directed proximally ( Figure 5D); bulb light yellow, ovate; embolus arising retrolateroproximally from bulb, slightly sigmoid, distad; conductor arising distally from bulb, slightly sigmoid, distad, with wide base; embolus and conductor widely separated (distance less than diameter of bulb).
Distribution. Myanmar. Known only from the type locality ( Figure 21). Natural history. Collected in a tropical evergreen forest at an altitude of 307 m.  Figure  7B); and by three oblique, elongate spermathecae on each side in females ( Figure 8A).
Distribution. Indonesia. Known only from the type locality ( Figure 22). Natural history. Collected among tree buttresses at an altitude of 465 m.   Etymology. The specific epithet is a noun in apposition taken from the type locality Phou Salao, Laos.
Diagnosis. Althepus phousalao Li & Li, sp. n. resembles A. leucosternum Deeleman-Reinhold, 1995, in having a triangular distal end of the conductor and one retrolateral spine of cymbium in males, and one spermatheca on each side in females. Males can be distinguished by the longer conductor (versus shorter in A. leucosternum) ( Figure 9B). Females can be distinguished by one thicker, longer spermatheca on each side (versus shorter in A. leucosternum) ( Figure 10A), can be distinguished from all the other known species of the genus by the thick spermathecae ( Figure 10A).
Female (paratype). Total length 3.20; carapace 0.94 length, 1.13 width; abdomen 1.72 length, 1.00 width. Similar to male in colour and general features of carapace ( Figure 10D, E) but smaller. Abdomen elongate, with complex patterns dorsally and ventrally. Internal genitalia with one curved, elongate spermatheca on each side ( Figure 10A). Distribution. Laos. Known only from the type locality ( Figure 21). Natural history. Collected in a pit of Phou Salao at an altitude of 242 m. Remark. Althepus phousalao Li & Li, sp. n., was labelled as "sp. 23" in Li and Li (2018).  Etymology. The specific name is derived from the Chinese pinyin 'qian huang', which means 'pale yellow', referring to the pale yellow colour of ocular area ( Figure  12C, D); adjective.
Diagnosis. Althepus qianhuang Li & Li, sp. n. can be distinguished from all other known species of the genus by the nearly parallel conductor and embolus in males ( Figure 11); by a large membranous sac extending posteriorly and 1-2 small round spermatheca(e) on each side in the internal genitalia of females ( Figure 12A).
Description. Male (holotype). Total length 4.49; carapace 1.55 length, 1.48 width; abdomen 2.80 length, 1.31 width. Carapace round, pale yellow, with brown lateral margins and one wide, brown median band, the middle one wider than the others ( Figure 12C). Anterior margin of cephalic region distinctly elevated. Cheliceral promargin with two teeth, followed by a lamina, retromargin with two small teeth ( Figure 20F), posterior surface of fang with 21 small denticles. Labium brown. Sternum brown. Abdomen elongate, with complex patterns dorsally and ventrally ( Figure 12C Figure 11A); bristles at the top of the cymbial protrusion ( Figure 11C) as in A. hongguangi Li & Li, sp. n.; bulb yellow, ovate; embolus arising distally from bulb, short, slightly curved; conductor arising distally from bulb, short, slightly curved; embolus and conductor slightly separated (distance less than diameter of bulb).
Female (   Etymology. The specific name is a patronym in honour of Dr. Qingyuan Zhao who collected the types; noun (name) in genitive case.
Diagnosis. Althepus qingyuani Li & Li, sp. n. can be distinguished from all other known species of the genus by 16 round spermathecae on curved stalks in the females ( Figure 13A).
Distribution. China. Known only from the type locality ( Figure 21). Natural history. Collected at a cave entrance at an altitude of 1499 m. Remark. Althepus qingyuani Li & Li, sp. n., was labelled as "sp. 97" in the analysis of Li and Li (2018).  Li & Li, sp. n. can be easily distinguished from all other known species of the genus by the widened, laminar embolus with a distal acuminate end ( Figure 14B); females, by the six round spermathecae on slender stalks on each side ( Figure 15A).
Distribution. Indonesia. East Kalimantan, Penajam ( Figure 22). Natural history. Collected in a lowland tropical forest. Remark. Althepus sepakuensis Li & Li, sp. n., was labelled as "sp. 131" in the analysis of Li and Li (2018). Etymology. The specific epithet is a patronym in honour of Mingjie Xu who collected the types; noun (name) in genitive case.   Li & Li, sp. n. resembles A. chengmenensis Li & Li, sp. n. in having a sigmoid conductor in the males, and curved, elongate spermathecae in the females. Males can be distinguished from the latter species by the smooth margin and blunt distal part of the conductor ( Figure 16B); females can be distinguished by the two shorter spermathecae on each side (versus longer in A. chengmenensis Li & Li, sp. n.) (Figs 2A, 17A), can be distinguished from all the other known species of the genus by the lateral spermathecae having a longer stalk than medial spermathecae ( Figure 17A).
Distribution. China. Yunnan Province (Figure 21). Natural history. Collected by sieving leaf litter in dark and moist environments. Etymology. The specific name is derived from the Chinese pinyin 'yi zhuang', which means 'sigmoid', referring to the sigmoid embolus ( Figure 18); adjective.    Li & Li, sp. n. can be distinguished from all other known species of the genus by the remarkably long and sigmoid embolus as well as by the absence of a conductor in males ( Figure 18). Females are distinguished by inconspicuous spermathecae ( Figure 19A).
Distribution. Indonesia. Known only from the type locality ( Figure 22). Natural history. Collected at a cave entrance at an altitude of 278 m. Remark. Althepus yizhuang Li & Li, sp. n., was labelled as "sp. 84" in the analysis of Li and Li (2018).

Discussion
In addition to morphological studies, we used molecular data from our extensive sampling to test the monophyly of the genus Althepus and delimitate the species (Li and Li 2018). The molecular topologies inferred by two different approaches all supported Althepus as a monophyletic group. The species delimitation inferred by three different approaches supported the evolutionary independence of 54 distinct lineages. For details, see Althepus sp. 23, Althepus sp. 84, Althepus sp. 97, Althepus sp. 119, and Althepus sp. 131 in figure 1 and supplementary figures S1-S4 of Li and Li (2018). In this paper, we describe seven new species in lowland habitats of southern Indo-Burma, Sunda shelf islands, and three new species in highlands of northern Indo-Burma. The genus appears to have a higher diversity in lowlands compared to highlands. Recent studies indicate that this may be due to the repeated isolation and reconnection of Southeast Asian landmasses caused by sea-level fluctuations (Liu et al. 2017, Li andLi 2018).