Four new species of the genus Otacilia Thorell, 1897 from Hunan Province, China (Araneae, Phrurolithidae)

Abstract Four new species of the genus Otacilia Thorell, 1897 are reported from Hunan Province, China: Otacilia hippocampa sp. n., Otacilia yangmingensis sp. n., Otacilia curvata sp. n., and Otacilia submicrostoma sp. n. All new species are described based on both sexes. In addition, the 55 known Otacilia species are divided into four species groups.


Introduction
Phrurolithidae Banks, 1892 was elevated to family rank by Ramírez (2014), consistent with the suggestion of Deeleman-Reinhold (2001). The family is currently represented by 211 species belonging to 14 genera worldwide. Of these, four genera and 65 species are recorded from China (World Spider Catalog 2016, Fu et al. 2015, Fu et al. 2016a. The Phrurolithidae are mostly ground-dwelling spiders living in leaf litter, especially bamboo leaves, woody debris or on the forest floor, very few species are found in the canopy (Deeleman-Reinhold 2001;Fu et al. 2014).
Otacilia Thorell, 1897 is one of the species-rich genera of the family comprising 55 species distributed in south-east Asia and east Asia. Among these Otacilia species, 35 are reported from China (Fu et al. 2015, Fu et al. 2016a, Fu et al. 2016b). The genus Otacilia was established by Thorell (1897) with description of O. armatissima based on a single female specimen from Myanmar.
The genus Otacilia is closely related to Phrurolithus C. L. Koch, 1839, comprising 74 species mostly distributed in the holarctic region. Until now, there is no clear way to differentiate between Otacilia and Phrurolithus. The diagnostic characters provided by Kamura (2005) were inaccurate (Wang et al. 2015), and the differences listed by Jäger and Wunderlich (2012) were also not distinct with the addition of more new species of these two genera. Wang et al. (2015) listed ten Chinese Otacilia species in two groups. Subsequently, Fu et al. (2016b) reviewed the 31 Chinese Otacilia species and agreed with Wang et al.'s (2015) assignment and also established a third species group to accommodate the Otacilia species: the armatissima group, the revoluta group, and the pseudostella group.
While examining the collections from Hunan Province, China, some Otacilia specimens were found that differed from the currently known Otacilia species. They are identified as four new species, Otacilia hippocampa sp. n., Otacilia yangmingensis sp. n., Otacilia curvata sp. n., and Otacilia submicrostoma sp. n., and are described and illustrated here.

Material and methods
The terminology used follows Jäger and Wunderlich (2012). All measurements given in the text are in millimeters. Total length is the sum of the carapace and abdomen lengths, regardless of the pedicel. Eye sizes were measured as the maximum diameter in dorsal or frontal view. Leg measurements are shown as: total length (femur, patella, tibia, metatarsus, tarsus). Epigyne were removed and cleared in a warm solution of 10% potassium hydroxide (KOH), transferred to ethanol and temporarily mounted for drawing. All specimens are preserved in 75% alcohol and were examined, drawn, and measured under a Leica M205A stereomicroscope equipped with an Abbe drawing device. Photographs were taken using a Leica M205A stereomicroscope equipped with a DFC450 CCD. The specimens are deposited in the Museum of Hebei University, Baoding, China (MHBU).
above sea level; B bursa;

Phrurolithidae Banks, 1892
Otacilia Thorell, 1897 Diagnosis. Chelicerae each with two bristles (rarely with one bristle) on anterior side; leg formula: 4123 (rarely 1423); spination: femora I-II d 0-2, III-IV d 0-1, I pl 3-6, II pl 0-3; tibiae I-II usually with 6-8 pairs of ventral spines; tibia I always one more rv than pv spine and tibia II always one more pv than rv spine; metatarsi I-II usually with 3-4 pairs of ventral spines, and always one more pv than rv spine. Male palp: femur with ventral apophysis or hump; tibia usually with single strong RTA, some species with BTA or DTA; embolus hook-shaped or needle-like, originating antero-prolaterally; tegular apophysis sclerotized or transparent, present or absent, antero-retrolaterally located; conductor membranous, well developed or absent. Female genitalia: epigynal median plate distinct or absent; vulva with pair of transparent bursae anteriorly and pair of strongly sclerotized spermathecae posteriorly.
Species groups of Otacilia. After reviewing 59 Otacilia species (including the four new Chinese species described in this paper), the grouping was revised and the current species assigned to four groups based on assessment of Fu et al. (2016b). The revoluta group was divided into two new groups, the longituba group (16 species) and the ambon group (two species). The armatissima group (29 species) and the pseudostella group (nine species) were preserved and updated. Three species were not assigned to any group because of their poor original description and figures or peculiar structure: Otacilia luzonica (Simon, 1898) (female is unknown; description and figures are not diagnostic), O. papilla Dankittipakul & Singtripop, 2014 (male is unknown; epigyne medially with lobe and absence of bursae) and O. paracymbium Jäger & Wunderlich, 2012 (female is unknown; cymbium with paracymbium).
Here the male and female diagnostic characters are listed for each species group, followed by a list of all of the included Otacilia species (Table 1). Etymology. The species name is taken from the Latin generic name of the seahorse, "Hippocampus", referring to the seahorse-shaped internal ducts (copulatory duct, connecting tube and spermatheca) in the female epigyne; adjective.
Distribution. Known only from the type locality, Hunan, China (Fig. 13).    Description. Male (Fig. 4A-B). Total length 3.04-3.16 (n = 7). Holotype: body 3.16 long; carapace 1.58 long, 1.31 wide; abdomen 1.58 long, 0.97 wide. Carapace light yellowish brown, lateral margin black, middle with broad longitudinal black stripe, from ocular area to the posterior margin of carapace; fovea longitudinal, distinct. Eye diameters: AME 0.11, ALE 0.12, PME 0.10, PLE 0.10. Eye interdistances: AME-AME 0.03, AME-ALE 0.01, PME-PME 0.10, PME-PLE 0.05, ALE-PLE 0.09. MOA 0.25 long, front 0.23 wide, back 0.27 wide. Clypeus 0.14 high. Chelicerae with two strong anterior bristles; promargin with three well separated teeth and retromargin with six denticles close to each other. Labium and sternum light yellow. Legs light yellowish brown. Femur I with two dorsal spines and four prolateral spines, femur II with one dorsal spine and two prolateral spines, femora III-IV with one dorsal spine; tibia I with seven proventral spines and eight retroventral spines, tibia II with seven pairs of ventral spines; metatarsi I-II with four pairs of ventral spines. Abdomen oval, dorsum black, anterior half with a narrow dorsal scutum, posterior half with several black transversal stripes; venter light grey, with black longitudinal stripes.
Palp (Figs 5A-D, 6A-C). Femur distally with an apophysis on ventral side anda retrolateral concavity. RTA broad, with sharp apex, base with a triangular process dorsally. Embolus slender, needle-like, slightly curved. Tegular apophysis sclerotized and thumb-shaped, situated at the apex of the bulb, separate from the embolus base.
Epigyne (Figs 5E-F, 6D): median plate narrow, with parallel lateral margin; copulatory openings situated centrally, covered with mating plugs (Fig. 5E), connected with a pair of shallow concavities anteriorly, and the concavities have distinct anterior and inner lateral margins. Vulva (Figs 5G, 6E): copulatory ducts thick, posteriorly swollen, connected to a pair of large, transparent long ovoid bursae; spermathecae located posteriorly and small, close to each other; bursae and spermathecae connected by slender, slightly curved connecting tubes.
Distribution. Known only from the type localities, Hunan, China (Fig. 13). Etymology. The specific name is derived from the Latin "curvatus", meaning curved and refers to the shape of the DTA of the male palp; adjective.
Palp (Figs 8A-D, 9A-C). Femur distally with an inflated hump on ventral side. RTA thick in proximal part and abruptly tapering at half of its length. DTA with anterior and posterior margins parallel in proximal part from the dorsal view, then abruptly curved to the prolateral side of bulb, tapering and with an enlarged blunt apex. Embolus short, needle-like. Conductor membranous, close to and as long as the embolus. Tegular apophysis absent but with a tegular ridge.
Distribution. Known only from the type localities, Hunan, China (Fig. 13).  Kamura, 2008 andO. parva Deeleman-Reinhold, 2001, by having only one tibial apophysis and no conductor and can be distinguished from them by the RTA base with a small triangular process (Figs 11A-D, 12A-C). The female of the new species can be easily distinguished from all of the other longituba group species by the long, S-shaped connecting peculiar tubes (Figs 11E-F, 12D).