A survey of Tmarus Simon, 1875 (Araneae, Thomisidae) from Fanjing Mountain Nature Reserve, Guizhou, China

Abstract Background Tmarus Simon, 1875 is a relatively large spider genus, currently includes 227 species distributed worldwide. Fanjing Mountain Nature Reserve is one of China’s most biodiverse regions. However, Tmarus can be regarded as being poorly represented in Fanjing Mountain, with only one species having been recorded so far: T.fanjing Yang & Yu, 2022. New information Recently, various expeditions to Fanjing Mountain Nature Reserve were carried out by the authors. In this paper, two Tmarus species were brought to light by those expeditions: T.fanjing Yang & Yu, 2022 and T.circinalis Song & Chai, 1990. T.fanjing is redescribed, based on new material and the female is described and illustrated for the first time. The supplementary micrographs of T.circinalis are given for the first time. The DNA barcodes and a distribution map of both species are provided for future use.


Introduction
Tmarus Simon, 1875 is the second most speciose genus of Thomisidae Sundevall, 1833, with 227 valid species distributed worldwide so far, after Xysticus C. L. Koch, 1835 (293 species), 27 species of which are recorded from China (World Spider Catalog 2023).
Although this genus is rather well known for its high species diversity, its taxonomy is very poorly studied: more than half of the species are known from a single sex or juveniles (five are described based on a juvenile; 143 species are known based on a single sex: for 53, only males are known, and for 90, only females are known) (World Spider Catalog 2023); for many species described in earlier studies, original descriptions are rather brief and lack illustrations or with inadequate illustrations Li 2009, Yang et al. 2022).
Fanjing Mountain Nature Reserve, one of China's most biodiverse regions, is located between 27°49'50"N to 28°01'30"N and 108°49'30"E to 108°18'30"E and is the core area of the Wuling Mountains (Qiu 2006). Fanjing Mountain as a representative of a primary forest ecosystem, famous for over 95% forest coverage (Guizhou Forestry Bureau 2014), known as 'Earth Oasis' or the 'gene pool of animals and plants'. The only list of Fanjing Mountain spiders was published by Song et al. (2006). In this book, a total of 126 species belonging to 71 genera and 18 families were recorded. However, this estimate of spider diversity is assumed to be far from the true diversity within this Nature Reserve (Wang et al. 2015). Despite the fact that Thomisidae represents a substantial fraction of southwest China foliage-dwelling spiders Li 2009, Tang andLi 2010), it can be regarded as being poorly represented in Mt. Fanjing, with only ten species from nine genera being clearly recorded: Diaea subdola O. Pickard-Cambridge, 1885, Ebrechtella tricuspidata (Fabricius, 1775), Lysiteles fanjingensis Wang, Gan & Mi, 2020, L. inflatus Song & Chai, 1990, Pharta tangi Wang, Mi & Peng, 2016, Phrynarachne mammillata Song, 1990, Strigoplus guizhouensis Song, 1990, Tmarus fanjing Yang & Yu, 2022, Thomisus labefactu s Karsch, 1881and Xysticus kurilensis Strand, 1907(Song et al. 2006, Song and Chai 1990, Wang et al. 2016, Wang et al. 2020, Yang et al. 2022. Additionally, before T. fanjing described from Mt. Fanjing, no species of this genus have been reported from this region (Yang et al. 2022).
Recently various short, but intensive field collections in Fanjing Mountain have been conducted by staff of the Guizhou Normal University and Guizhou Education University. This paper reports our findings on the study of recently-available samples from the area, which revealed a new record species of Fanjing Mountain, T. circinalis Song & Chai, 1990, as well as the hitherto unknown female of T. fanjing. The aims of the current paper are: 1) to redescribe the male and report the female of T. fanjing for the first time; 2) to re-illustrate T. circinalis, based on new material from Mt. Fanjing and give supplementary micrographs; 3) to provide the DNA barcodes and a distribution map of T. fanjing and T. circinalis for future use.

Materials and methods
Specimens in this study were collected by beating vegetation. Spiders were fixed and preserved in 95% ethanol. Specimens were examined with an Olympus SZX7 stereomicroscope; details were studied with an Olympus CX41 compound microscope. Female epigynes and male palps were examined and illustrated after being dissected. Epigynes were removed and cleared in warm lactic acid before illustration. The vulva was also imaged after being embedded in Arabic gum. Photos were made with a Cannon EOS70D digital camera mounted on an Olympus CX41 compound microscope. The digital images were taken and assembled using Helifocus 3.10.3. software package (Khmelik et al. 2006).
The distribution map was generated with ArcGIS v. 10.5 (Environmental Systems Research Institute, Inc.). Due to lack of locality coordinates in previous publications, locality coordinates for T. circinalis in Hubei Province and Chongqing City were originated from ArcGIS (see Song and Chai (1990)).
All measurements were obtained using an Olympus SZX7 stereomicroscope and given in millimetres. Eye diameters are taken at the widest point. The total body length does not include chelicerae or spinnerets length. Leg lengths are given as total length (femur, patella, tibia + metatarsus, tarsus). Most of the terminologies used in text and figure legends follows Tang and Li (2009) and Zhang et al. (2022).

Taxon treatments
Abdomen ( Fig. 1A-C) elongate, pyriform or shaped like a shield in dorsal view, tapering posteriorly, posteriorly with a prominent caudo-dorsal hump. Dorsum basically grey or light brown, with many long spiniform setae and greyish spots; venter yellowish-white, without distinct pattern; spinnerets brown. Legs uniformly yellowish-white ( Fig. 1A  Epigyne (Fig. 2C-F). Epigynal plate slightly longer than wide, anterior and lateral margin not delimited, posterior margin rebordered; spermathecae (SP) clearly visible through the tegument in ventral view. Epigynal plate with an atrium (A) and a hood (H). Atrium large, represented by a deep depression, more than 2/3 epigyne width, anterior margin not rebordered, posterior margin delimited by the heavily sclerotised hood. Hood more or less ˽-shaped, nearly as wide as epigyne. Copulatory openings (CO) indistinct, at basolateral atrial borders, leading to copulatory ducts (CD) which descend obliquely to connect with spermathecae (SP). Spermathecae reniform, about 1.73 longer than wide, the two spermathecae separated by about one diameter. Fertilisation ducts (FD) acicular, membranous, located terminally on spermathecae.

Taxon discussion
The species Tmarus fanjing Yang & Yu, 2022 was first described, based on male specimens only from Mt. Fanjing of Guizhou Province, China. Detailed description, diagnosis, high quality photographs and DNA barcoding of the holotype are provided in the original paper (see Yang et al. (2022)), to allow for easy species recognition. Recently, new materials containing both sexes were collected from the type locality and near the type locality (Mt. Foding, Guizhou Province, China; Fig. 7) simultaneously and seemed to be this species, based on comparison with the type specimen. DNA barcodes (a partial fragment of the mitochondrial cytochrome oxidase subunit I gene, COI) of the new materials was also obtained to confirm gender matching and species identification.