Taxonomic studies on the genus Ectatosticta (Araneae, Hypochilidae) from China, with descriptions of two new species

Abstract Species of the spider family Hypochilidae Marx, 1888 from China are studied, including two known species and two new species of the genus Ectatosticta Simon, 1892. The new species are E. wukongsp. nov. (♂♀) from Sichuan and E. xuanzangsp. nov. (♀) from Tibet.


Introduction
Hypochilidae Marx, 1888 is a small family that includes two genera: Hypochilus Marx, 1888 and Ectatosticta Simon, 1892. Hypochilus is endemic to the USA and includes ten species, whereas Ectatosticta is endemic to China and until now only included two species: E. davidi (Simon, 1889) from Shaanxi and E. deltshevi Platnick & Jäger, 2009from Qinghai (WSC 2020, Li 2020. Hypochilidae was considered the sister group of all other araneomorph spiders (Platnick 1977), but Wheeler et al. (2017) confirmed that Hypochilidae is the sister group of Filistatidae Simon, 1864. Unlike Hypochilus, Ectatosticta build simple sheet webs between soil blocks, huge rocks or in tree trunks. On one side of the web of some species there is a tube-retreat which typically extends into rock crevices, soil or between roots.
In this paper, photographs of two known Ectatosticta species are provided, of which E. davidi (Simon, 1889) is based on material collected near the type locality and E. deltshevi Platnick & Jäger, 2009 is based on the male holotype and females from the same locality as the holotype. In addition, two new species of the genus Ectatosticta are described: E. wukong sp. nov. (♂♀) from Sichuan and E. xuanzang sp. nov. (♀) from Tibet.

Material and methods
All specimens were preserved in 75% ethanol. Female genitalia were cleared in a trypsin enzyme solution to dissolve non-chitinous tissue. Specimens were examined under a LEICA M205C stereomicroscope. Photomicroscope images were taken with an Olympus C7070 zoom digital camera (7.1 megapixels). Photos were stacked with Helicon Focus 6.7.1 (Khmelik et al. 2006) and processed in Adobe Photoshop CC 2018.
All measurements are in millimeters. Eye sizes are measured as the maximum diameter from either the dorsal or frontal view. Leg measurements are given as follows: total length (femur, patella + tibia, metatarsus, tarsus). Distribution maps were generated using ArcMap software 10.2 (ESRI 2002 Diagnosis. Ectatosticta can be easily distinguished from Hypochilus by the rectangular labium which is almost as long as wide and bears a pair of triangular posterolateral flanges, also by numerous leg spines (Forster et al. 1987) and in the lateral view of the male palp, the cymbium to bulb length ratio is almost 3:1 (Figs 2, 4) but nearly 1 : 1 in Hypochilus (Forster et al. 1987: figs 38, 43, 48, 53, 58, 63, 68, 73).
Key to Ectatosticta males 1 Male palp with fewer than 5 thickened setae, the most dorsal setae are dispersed, and the length ratio of the embolus to the embolus base is more than 2 : 1 (Fig. 1)  Male palp with 5-7 thickened setae, all closely appressed one another, and the length ratio of the embolus to the embolus base is almost 1 : 1 (Fig. 1)   The ratio of the length of the inner spermathecae to the outer spermathecae is almost 1 : 1 to 1 : 2 ( Fig. 5A Distribution. China (Qinghai). Natural history. Living in simple sheet webs between soil blocks or tree roots. On one side of the web there is tube-retreat that extends into the soil.   Etymology. The species is named after Wukong, a character in the classic Chinese novel Journey to the West, noun. Journey to the West was written during the Ming Dynas- Qinghai (close to the type locality of E. deltshevi), to South Xinjiang, Tibet (near the type locality of E. xuanzang sp. nov.) and India.
Diagnosis. Males of E. wukong sp. nov. can be distinguished by having only two thickened setae retrolaterally on the cymbium and the length ratio of the embolus to the embolus base is almost 3 : 1 (Fig. 3C, D). Females can be distinguished by having one pair of spermathecae (Figs 5C, 6D, E).
Male palp (Figs 2C, D, 3C, D, 4C, D) simple, cymbium long, retrolaterally with an apophysis divided into two parts: a small, semicircular lobe with a seta and a large lobe with two strong setae placed closely together. Embolus thin, length ratio of embolus to embolus base 3:1. Conductor sickle-shaped.
Male. Unknown. Distribution. Known only from the type locality. National history. In damp rocky areas, hiding between huge stones. They build simple sheet webs without a tube-retreat. Figure 7. Photos of live Ectatosticta spp. A E. deltshevi, female from Qinghai B E. deltshevi and web C E. xuanzang sp. nov., holotype from Tibet D E. xuanzang and web E Egg sac F A typical web of Ectatosticta. Egg sac marked with green arrow, spider marked with red arrow and assembled nymphs marked with yellow rectangle. Platnick & Jäger (2009) pointed out that the number of thickened setae in males of Ectatosticta deltshevi was four, whereas in E. davidi it was five to seven. However, it is necessary to examine more male specimens to learn more about the extent of variation. Based on the examination of all female specimens available, the extent of sclerotization of the spermathecae seems stable within the species. This study is currently being expanded to include molecular data and additional specimens from southwestern China and the Himalayas which will continue to increase our knowledge of Ectatosticta.