﻿On five new species of the genera Araneus and Hypsosinga (Araneae, Araneidae) from Vietnam

﻿Abstract Five new species of the spider family Araneidae Clerck, 1757 from Vietnam are described: Araneuseugeneisp. nov. (♂♀), A.ethanisp. nov. (♀), A.liamisp. nov. (♂♀), Hypsosingaryanisp. nov. (♂♀), and H.zionisp. nov. (♀). Diagnostic photographs of the habitus and copulatory organs are provided. Types of the new species are deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) in Beijing, China.


Introduction
A comprehensive checklist of spiders from Vietnam was first compiled by Pham et al. (2007), who listed 320 spider species in 32 families and 159 genera. The number of spider species in Vietnam was later increased to 456 species of 41 families by Ono et al. (2012), who included 23 genera and 68 species of araneids. Few studies on spiders of Vietnam were made after 2012 other than Lin et al. (2023) and Wang et al. (2023). However, the true number of Vietnam spider taxa is probably much higher than currently known.
The goal of this paper is to describe five new species collected in three national parks (Cuc Phuong, Cat Ba, and Tam Dao national parks) in northern Vietnam.

Material and method
All specimens were collected by canopy fogging, leaf-litter sieving, or hand collecting and are preserved in 75% ethanol. Type specimens of new species are deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS) in Beijing. The specimens were examined with an Olympus SZX16 stereomicroscope. The epigynes were cleared in lactic acid for examination and imaging. The left male palps were dissected in ethanol for examination, description, and imaging. Photographs of the habitus and copulatory organs were taken with a Kuy Nice digital camera mounted on an Olympus BX43 compound microscope. Compound focus images were generated using Helicon Focus v. 6.7.1.
All measurements are given in millimeters. Leg measurements are given as total length (femur, patella + tibia, metatarsus, tarsus). Abbreviations used in the text and figures are as follows: ALE anterior lateral eye; AME anterior median eye; C conductor; CD copulatory duct; CO copulatory opening; E embolus; FD fertilization duct; MA median apophysis; MOA median ocular area; PLE posterior lateral eye; PME posterior median eye; Sc scape; Sp spermatheca; TA terminal apophysis.
Comments. Although the three new Araneus species in this paper differ greatly from the type species A. angulatus in both somatic and copulatory organs, they are placed in Araneus provisionally until a phylogenetic analysis is conducted. The three new species, along with A. bidentatus Mi & Li, 2022, A. bidentatoides Mi & Li, 2022, and A. semiorbiculatus Mi & Li, 2022, show some common somatic characters, such as a more or less dark brown carapace, eyes with black bases, an abdomen that is longer than wide, a female abdomen with at least a pair of low humps; these characters indicate these species must be closely related, although their copulatory organs differ. smoothly rounded in retrolateral; median apophysis ~1.4× wider than long, heavily sclerotized, tapered end pointed to tip of cymbium; embolus ~0.5× length of bulb diameter in prolateral view, tapered distally; conductor membranous, longer than wide; terminal apophysis about half bulb diameter width at base, tapered and curved distally.
Epigyne ( Fig. 3A-D): ~2.8× wider than long in ventral view; scape truncated, ~6.0× wider than long in anterior view; copulatory openings slit-like, situated on ventral surface; copulatory ducts longer than spermatheca diameter, curved about 90°; spermathecae globular, about one diameter apart. Etymology. The species name is a boy's name from Vietnam; noun (name) in genitive case.
Diagnosis. The new species resembles A. bidentatus Mi & Li, 2022 in appearance, but can be distinguished from it in having: 1) the copulatory openings situated on the anterior surface of the epigyne (Fig. 4B, C) vs at the lateral ends of the scape groove (Mi and Li 2022: fig. 3A, B); 2) the scape not grooved (Fig. 4A-D) vs grooved (Mi and Li 2022: fig. 3A, B); 3) the tibia of the male palp with three heavily sclerotized, denticulate protuberances (see arrows in  and interdistances: AME 0.13, ALE 0.08, PME 0.10, PLE 0.10, AME-AME 0.15, AME-ALE 0.10, PME-PME 0.10, PME-PLE 0.18, MOA length 0.33, anterior width 0.38, posterior width 0.33. Leg measurements: I 5.30 (1.60, 1.90, 1.15, 0.65),  Carapace dark brown, with yellow median patches anterior to and around fovea and on lateral edges of thoracic region; cervical groove inconspicuous. Chelicerae yellowish brown, with five promarginal and three retromarginal teeth. Endites and labium yellowish brown, paler distally. Sternum dark brown with wide yellow band. Legs brown with grayish-brown annuli; tibia I with 13 macrosetae; tibia II with 10 macrosetae; tibia III with six macrosetae; tibia IV with nine macrosetae. Abdomen elliptical, ~1.3× longer than wide, covered with dark setae; dorsum yellow with grayish brown patches; venter yellow with irregular grayish brown markings. Spinnerets yellowish brown. Palp (Fig. 5): with two patellar bristles; tibia ~3.0× wider than long in retrolateral view, with three heavily sclerotized, denticulate protuberances and a short ventral projection; paracymbium finger-like; tegulum smoothly rounded in retrolateral view; median apophysis longer than wide, with pointed tip bent about 90°, distal end pointed toward the tip of cymbium in prolateral view; embolus thread-like; conductor curled, covering most of embolus in prolateral view; terminal apophysis about as long as bulb diameter, bifurcated distally.
Type species. Singa sanguinea C.L. Koch, 1844. Comments. The two new Hyposinga species in this paper differ greatly from the type species, H. sanguinea, in their copulatory organs. They are placed in Hyposinga provisionally because they show some common somatic characters, such as small total length, reflective carapace, and abdomen. Etymology. The species name is a boy's name from Vietnam; noun (name) in genitive case.
Epigyne (Fig. 6A-C): ~2.3× wider than long in ventral view, lacking scape; copulatory openings rounded, situated at the lateral side of ventral surface; copulatory ducts about of equal length to spermatheca diameter; spermathecae globular, about one radius apart.
Distribution. Vietnam (Ha Tay and Cao Bang provinces). Diagnosis. The new species resembles the female of H. ryani sp. nov. in appearance, but it can be distinguished from the latter in having: 1) the epigyne with scape ( Fig. 8A-D) vs scape lacking (Fig. 6A); 2) the copulatory openings situated on the posterior surface of the epigyne (Fig. 8C, D) vs on the ventral surface (Fig. 6A); 3) the spermathecae touching each other (Fig. 8D) vs apart (Fig. 6B, C); and 4) dorsum of abdomen with three transverse bands (Fig. 8E) vs only one band (Fig. 6D).