A new genus and species of leptonetid spiders (Araneae, Leptonetidae) from Guangdong Province, China

Abstract Background The spider family Leptonetidae Simon, 1890 includes 20 genera and 366 species from North America, the Mediterranean Region and Asia. Currently, 132 species belonging to six genera have been recorded in China. New information A new genus and species of leptonetid spiders, Yueleptonetadongxing gen. et sp. n., is described from Guangdong Province, China. Yueleptoneta gen. n. is distinct from the other genera in the chelicerae having the stridulatory file on the lateral margin and the male palp having a tarsal spur, lacking strong spines or apophyses on the femur and tibia.


Introduction
Members of the family Leptonetidae Simon, 1890 are tiny (1-3 mm) and typically have six eyes, with posterior median eyes displaced behind the anterior lateral eyes and posterior lateral eyes, anterior median eyes lost. Most species live in moist habitats, such as leaf litter, under rocks and especially in caves (Ledford et al. 2021).
In this paper, a new genus and species of leptonetid spiders, collected from the leaf litter in Guangdong Provnice of China, is described and illustrated.

Materials and methods
The specimens were examined using a Leica M205C stereomicroscope. Details were studied under an Olympus BX51 compound microscope. Photomicroscope images were made with a Canon EOS 750D zoom digital camera (18 megapixels) mounted on an Olympus BX51 compound microscope. Photos were stacked with Helicon Focus 6.7.1 and processed in Adobe Photoshop CC 2020. For scanning electron microscopy (SEM), specimens were air-dried, sputter-coated using IXRF SYSTEMS and imaged with a Hitachi TM3030 SEM. Leg measurements are shown as: total length (femur, patella, tibia, metatarsus, tarsus) and, when missing, was coded as "-". Palp measurements are shown as: total length (femur, patella, tibia, tarsus). All measurements were taken using an Olympus BX51 compound microscope and are in millimetres.
All specimens are preserved in 75% ethanol. The type material is deposited in the College of Life Science, Shenyang Normal University (SYNU) in Liaoning, China.

Description
Carapace brown and median groove needle-shaped, distinct. Six-eyed ( Fig. 1D and Fig. 3A). ALE and PLE contiguous, PME posteriorly displaced. Chelicera with stridulatory file on the lateral margin (Fig. 2F, I and J). Endite anterior margin with serrula ( Fig. 2D and E). Patellar gland oval (Fig. 2G, H and K). Opisthosoma with distinct patterns. Palp (Fig. 1G-I and Fig. 2A-C): femur and tibia without strong spines; tarsus with a spur at tip. Palpal bulb with a leaf-shaped embolus and a membranous, flattened conductor. Female internal genitalia with a pair of highly coiled spermathecae and sperm ducts ( Fig. 3D and E).

Diagnosis
Male of the genus Yueleptoneta gen. n. is similar to Leptonetela Kratochvíl, 1978 and Longileptoneta Seo, 2015 in having a strong palpal tarsal spur ( Fig. 1G-I, Fig. 2A and B), but can be distinguished from both genera by the palpal femur, tibia and tarsus lacking strong spines (Fig. 1D-I) (vs. palpal tibia with a row of spines in Leptonetela (Wang et al. 2017: figs 4C and D) and palpal femur with strong spines and palpal tarsus with a prolateral distal spur in Longileptoneta (Seo 2015: figs 1C-G)) and the chelicerae having the stridulatory file on the lateral margin ( Fig. 2F) (vs. lacking stridulatory file in both genera). Male of the new genus is also similar to Leptoneta Simon, 1872 in the palpal femur and tibia lacking strong spines, but can be distinguished by having the palpal tarsal spur (vs. lacking palpal tarsal spur, but having strip-shaped appendices in Leptoneta ( Le Peru 2011: fig. 118)). Female of the new genus is similar to Leptonetela Kratochvíl, 1978 by having strongly coiled spermathecae (Fig. 3E), but can be distinguished by the chelicerae having the stridulatory file on the lateral margin ( Fig. 2I and J).

Etymology
The generic name is derived from the Pinyin word "Yue", referring to Guangdong Province (Yue is a short name for Guangdong), where the material has been collected and the genus name Leptoneta Simon. The gender is feminine.

Diagnosis
Specimens of Yueleptoneta dongxing sp. n. are distinguished by the characters discussed in the genus diagnosis section.

Etymology
The specific name is a noun in apposition and refers to the type locality.