﻿Simonia gen. nov., a new spider genus (Araneae, Theridiosomatidae) from Southeast Asia

﻿Abstract A new theridiosomatid genus, Simonia Yu & Lin, gen. nov., is described, with Baalzebubyouyiensis Zhao & Li, 2012 (♂♀, China, Vietnam and Laos) as the type species. Three species are included in Simoniagen. nov., i.e., S.youyiensis (Zhao & Li, 2012) comb. nov. ex. Baalzebub, S.steineri Yu & Lin, sp. nov. (♀, Huapan, Laos), and S.sumatra Yu & Lin, sp. nov. (♀, Sumatra, Indonesia). A key to theridiosomatid genera endemic to the Oriental Realm and a key to species of the new genus are provided, as well as diagnoses, descriptions and a distribution map for the species of Simoniagen. nov.


Introduction
Theridiosomatidae Simon, 1881 is a small spider family with 137 extant species in 20 genera which are mainly distributed in tropical and subtropical regions, including 28 species in 11 genera recorded in China (WSC 2023).Most theridiosomatids from the Oriental Realm have been well studied, described in detail alongside high-quality illustrations, allowing easy recognition thanks to several reviews and revisions (Miller et al. 2009;Chen 2010;Dou and Lin 2012;Zhao and Li 2012;Labarque and Griswold 2014;Lin et al. 2014;Feng and Lin 2019;Suzuki et al. 2020Suzuki et al. , 2022;;Lin et al. 2022;Yang et al. 2022;Zhang et al. 2023).Despite the above-mentioned, the taxonomic relationships among some genera, such as Baalzebub Coddington, 1986 and its closest-related genera (e.g., Karstia Chen, 2010 andSennin Suzuki, Hiramatsu &Tatsuta, 2022) are not yet well defined (Suzuki et al. 2022).And debate on the monophyly and delimitation of Baalzebub remains open, with much long-running dispute about genus placements of some Baalzebub species (Coddington 1986;Suzuki et al. 2022).Further, Baalzebub sensu lato has an unusual distribution, occurring disjunctively in the Neotropical Realm, Australia (Queensland) and southern China (WSC 2023).In addition, too many morphologically different species are placed in Baalzebub sensu lato indicating that the genus is definitely not monophyletic.ZooKeys 1185: 277-294 (2023), DOI: 10.3897/zookeys.1185.104120 Jianshuang Zhang et al.: Simonia gen. nov. from Southeast Asia While examining spiders collected from Laos and Vietnam, we came across some specimens which are reported here as belonging to two new species.Both the new species possess several morphological characters shared with Baalzebub youyiensis Zhao & Li, 2012, a known species widespread from Laos to Guangxi Zhuang Autonomous Region of southern China.These three species share a set of characters that distinguish them from other theridiosomatid genera, especially from Baalzebub sensu stricto (e.g., the generotype, B. baubo Coddington, 1986 and its related species from Neotropical Realm).Therefore, we are describing Simonia Yu & Lin, gen.nov., to accommodate the three species endemic to Southeast Asia.The goal of this paper is to provide a description of the new genus and two new species as well as redescription of B. youyiensis chosen as a type species of new genus.

Materials and methods
Specimens were examined and measured with a Leica M205 C stereomicroscope.Further details were studied with an Olympus BX43 compound microscope.Copulatory organs were examined after they were dissected and detached from the bodies.Epigynes were removed and treated with lactic acid before being photographed.All specimens were preserved in 95% ethanol.Photos were taken with a Canon EOS 60D wide zoom digital camera (8.5 megapixels) mounted on an Olympus BX43 stereomicroscope.The images were montaged using Helicon Focus ver.3.10 ( Khmelik et al. 2006) image stacking software.All measurements in the paper are in millimetres.Leg measurements are given in the following sequence: total length (femur, patella, tibia, metatarsus, and tarsus).
The distribution map was generated with ArcGIS ver.10.
Etymology.The generic epithet is named after the French arachnologist Eugène Louis Simon, in recognition of his inception of Theridiosomatidae.
Diagnosis.Simonia gen.nov.resembles Sennin Suzuki, Hiramatsu & Tatsuta, 2022 in general shape of copulatory organs.Male palps of these two genera have similar embolic divisions with at least three bristle-like, sharp embolic apophyses; epigynes of both genera have similar spoon-shaped or equicrural triangular scape.Simonia gen.nov.can be distinguished from Sennin by a combination of following characters: cymbial outgrowth (cymbial apophysis) absent (vs present), conductor axe-shaped, almost hyaline and with vein-shaped grains (vs not axe-shaped, membranous, without vein-shaped grains), embolus long, extending to the distal part of embolic division, terminally torch-shaped, with a cylindric stalk and a multiramose apex (vs shorter and apex blunt, located at the proximal part of embolic division, embolic terminal absent), all embolic apophyses are not coiled (vs strongly curved or coiled), embolic division dorsally with large, hyaline lobe (vs embolic lobe absent) (cf.Figs 1-3 and Suzuki et al. 2022: figs 7, 9); epigynal plate surface distinctly wrinkled, with a distinctive transverse fold at midlength between anterior and posterior margins (vs surface slightly wrinkled, medially without the distinctive transverse fold), the anterior part of spermathecae fused (vs not fused, just only overlapped), copulatory duct indistinct, the course of the copulatory duct simple, forming a loop in the inside of copulatory bursa (vs distinct, and course more complex, with a coiled trajectory at the basal side of the spermathecae), copulatory bursa large, nearly as long as epigyne length (vs smaller or indistinct, barely longer than 1/2 length of epigynal plate) (cf.Figs 4E-G, 5C-E, 6C-E and Suzuki et al. 2022: figs 8, 10).
Description.Small sized with body length 1.50-1.65 in males and 1.90-2.45 in females; carapace 0.83-0.96long in males and 0.91-1.08 in females.Carapace nearly pyriform, in profile highest just behind ocular area, gradually sloping to pedicel, c. 1.35-1.45times longer than high; carapace smooth, with long, sparse setae, yellow brown to dark brown, slightly darker anteriorly; cervical groove V-shaped, radial grooves and fovea indistinguishable.Sternum yellowish brown to dark, distinctly darker than carapace, clothed with dense setae, heart-shaped, anterior edge truncate, anterior and lateral margins with brown extensions fitting intercoxal concavities; posterior region strongly protruding between coxae IV.Female palp distally with erect, thin, dark bristles.Chelicerae slightly darker than carapace.Labium triangle shaped.Maxillae nearly trapezoidal, anterior edge straight, anterior and lateral margins slightly curved, slightly convergent posteriorly, with dense scopulae on inner margins.Legs long, uniformly coloured, slightly lighter than carapace, with darker femora and coxae I. Leg formula 1243.Abdomen ovoid, nearly as long as wide, abdominal colours and patterns variable; marginally clothed with sparse long setae, ventrally covered by fine short setae.Spinnerets brown.Male palp: same as in type species.Epigyne with small, hyaline scape (SC); epigynal plate surface distinctly wrinkled, with distinctive transverse fold (TF) at midlength between anterior and posterior margins; scape (SC) extending from posterior margin of epigynal plate, translucent; copulatory openings indistinct; copulatory duct (CD) indistinct, with simple course, forming loop in inside of copulatory bursa; spermathecae (Sp) consist of relatively large head (SS, anterior part) and slightly narrower stalk (SS, posterior part), and in addition with distinctly small base (SB, distal part) in S. sumatra sp.nov.; spermathecal heads fused, located centrally and juxtaposed; fertilization ducts (FD) acicular, membranous, located on basal surface of spermathecae; copulatory bursae (CB) represented spherical or oval sacs, large, nearly as long as epigyne length, surface hyaline, wrinkled and ribbed, bursae touching each other.
Comments.A preliminary genus-level taxonomic molecular analysis of Theridiosomatidae from Southeast Asia was carried, based on five targeted genes (two mitochondrial genes: 16S and COI; three nuclear genes: 18S, 28S, and H3).According to the results (unpublished): (1) the monophyly of the genus Simonia gen.nov. is supported; (2) this new genus is related to two genera exclusively distributed in SE Asia, Karstia and Sennin.Morphologically, the new genus is also similar to Karstia, but can be distinguished by the absence of cymbial outgrowth, presence of torch-shaped embolic terminal and large, hyaline embolic lobe, and by the fused anterior parts of the spermathecae, large copulatory bursa, as well as a set of other characters of the copulatory organs (see diagnosis of the genus above and key to theridiosomatid genera endemic to Oriental Realm below).
The type species of Simonia gen.nov., S. youyiensis was originally assigned to the Baalzebub, although it did not show typical Baalzebub features.Baalzebub is definitely not monophyletic.There is a strong possibility that Baalzebub sensu stricto contains only two species from the Neotropical Realm: B. baubo and B. albonotatus (Petrunkevitch, 1930).These Neotropical Baalzebub species share the following distinctive suite of characters, here contrasted with the corresponding condition in Simonia gen.nov.: 1) embolic apophyses spatulate, thick and blunt (vs bristle-like and slender, apically sharp); 2) embolus clawshaped, not branched (vs torch-shaped, with a cylindric stalk and a multiramose apex); 3) embolic lobe absent (vs present); 4) conductor not axe-shaped, surface smooth (vs axe-shaped, surface with many vein-shaped grains); 5) scape large, at least longer than 1/2 length of epigynal plate (vs small, no more than 1/4 length of epigynal plate); 6) epigynal plate surface smooth (distinctly wrinkled, with a distinctive transverse fold); and 7) copulatory bursa surface smooth, small, less than 1/2 length of epigynal plate (surface wrinkled and ribbed, large, as long as length of epigyne) (cf.Coddington 1986: figs 161-164, 183, 184, 186, 187 and Figs 1-3, 4E-G, 5C-E, 6C-E).In view of the above-mentioned facts, it is currently impossible to discern any obvious derived features that could indicate a close relationship between S. youyiensis and the genus Baalzebub sensu stricto, leaving no doubts that our new combination and the establishment of a new genus are correct.Diagnosis.Females of S. youyiensis are most similar to those of S. sumatra sp.nov.by having similar habitus and general shape of the vulva.Simonia youyiensis differs from S. sumatra sp.nov. in 1) anterior margin of the epigynal plate slightly concaved (c.140°) (vs concaved c. 120°) (cf.Fig. 4E, F and Fig. 6C, D), 2) spermathecae comma-shaped (vs spermathecae shaped like the whole hind leg of a frog) (cf.Fig. 4G and Fig. 6E), and 3) bursae spherical (vs egg-shaped) (cf.Fig. 4G and Fig. 6E).

A B C D F G E
tubercle, slightly longer than 1/2 length of tegulum.Median apophysis (MA) small, about 2/5 length of tegulum, shaped like tadpole, consisting of relatively wide head (distal part) and narrow tail (proximal part); distal process blunt, apex round and rough, with many tiny and scale-like tooth; proximal process triangular, gradually narrowing toward its apex, apex sharp.Conductor (Co) large and axe-shaped, aligned transversely on anterior part of bulb; almost all of conductor hyaline and with vein-shaped grains, except membranous distal margin.Embolic division nearly as long as conductor, hidden behind conductor, consisting of broad embolic lobe (EL), embolic terminal (ET), and at least 3 apophyses (EA); embolic terminal short, less than 1/2 length of embolic lobe, shaped like a torch, with cylindric stalk and multiramose apex; all embolic apophyses bristle-like and slender, slightly longer than embolic terminal; some apexes of embolic terminal and embolic apophyses overpass distal margin of conductor.
Distribution.Known only from the type locality, Guesthouse cave, Huapan Province, Laos (Fig. 7).Etymology.The species name is derived from the type locality; noun in apposition.

Simonia sumatra
Diagnosis.The female of the new species resembles those of S. youyiensis in having similar habitus and general appearance of the epigyne (cf.Fig. 6 and Fig. 4C-G), but can be easily distinguished by 1) anterior margin of epigynal plate concaved c. 120° (vs c. 140°) (cf.Fig. 6C, D and Fig. 4E, F), 2) spermathecae shaped like the whole hind leg of a frog, consisting of head, stalk and base (vs comma-shaped, only with head and stalk) (cf.Fig. 6E and Fig. 4G), and 3) bursae egg-shaped (vs spherical) (cf.Fig. 6E and Fig. 4G).
Distribution.Known only from the type locality, West Sumatra, Indonesia (Fig. 7).