﻿Three new Stenohya species with sexually dimorphic leg I from China (Pseudoscorpiones, Neobisiidae)

﻿Abstract Three new species of the genus Stenohya Beier, 1967 from China are described: Stenohyagibbasp. nov. and S.papillatasp. nov. from Hunan Province, and S.guangmingensissp. nov. from Jiangxi Province. In addition to their sexually dimorphic pedipalp, these three new species also have a uniquely sexual dimorphic leg I, which has not been reported in other Stenohya species. Additionally, an updated key to the Chinese Stenohya species is provided.


Introduction
Stenohya Beier, 1967, originally placed in the family Hyidae (Beier 1967), was erected with the type species S. vietnamensis Beier, 1967 and transferred to the family Neobisiidae by Harvey (1991), based on the presence of venom apparatus only in the fixed chelal finger and the presence of a non-lanceolate trichobothrium t.Of the 23 Stenohya species known, 14 of them occur in China (WPC 2022;Li and Shi 2023).These 14 species mainly occur in the southern region of China, except for S. xiningensis, which is lives in the northern region.Stenohya mainly lives in leaf litter and soil, under rocks, bark, and fern fronds.
In this study, three new Stenohya species with sexually dimorphic pedipalps and leg I are described from China: S. gibba sp.nov., S. papillata sp.nov., and S. guangmingensis sp.nov.

Materials and methods
All specimens were preserved in 75% alcohol.Temporary slide mounts were prepared in glycerol.Detailed examinations were carried out with an Olympus BX53 general optical microscope.Photographs and measurements were taken using a Leica M205A stereomicroscope equipped with a Leica DFC550 camera.Drawings were made using the Inkscape ver.1.0.2.0.Figures were edited and formatted using Adobe Photoshop 2022.The specimens were deposited in the Museum of Hebei University (MHBU), Baoding, China.
Terminology and measurements largely follow Chamberlin (1931), except for the nomenclature of the pedipalps and legs, and the terminology of trichobothria (Harvey 1992); the term "rallum" (for flagellum) is adopted from Judson (2007).Etymology.The specific name is derived from the Latin word "gibbus", meaning hump-shaped, which refers to the shape of the projections on the basitarsus and telotarsus of the male leg I.
Description.Adult male (holotype and male paratypes) (Figs 1A, 2A).Carapace (Figs 3A,4A).Carapace 1.30-1.36times longer than broad, with a total of 30-32 setae, including six near anterior margin and 6-7 near posterior margin; eight lyrifissures near the eyes, four lyrifissures near posterior margin; epistome small, triangular, with rounded top; with four corneate eyes.Carapace divided into three parts by two transverse, shallow grooves, the anterior part uplifted, the median part smooth, the posterior part uplifted, and with microgrooves.
Carapace (Figs 5A,6A).Carapace 1.02-1.19times longer than broad, with a total of 29-30 setae, including six near anterior margin and 4-5 near posterior margin; ten lyrifissures near the eyes, five lyrifissures near posterior margin; the front half of carapace uplifted, the back half smooth and with triangular invagination at 1/3 and 2/3 positions.
Remarks.The male of this new species differs from all other species of the genus Stenohya by the presence of a large columnar projection on the lateral side of basitarsus and telotarsus.The female can be distinguished from other Stenohya species reported from China by the presence of 79-87 teeth on pedipalpal movable chelal finger (115-118 in S. arcuatа; 68 in S. bomica; 96-98 in S. hainanensis; 46-51 in S. huangi; 45-55 in S. pengae), the pedipalpal chela with pedicel 4.67-4.98times longer than wide (4.20 in S. bicornuta; 4.19-4.37 in S. curvata; 4.16-4.27 in S. hainanensis; 3.56 in S. meiacantha; 4.09-4.25 in S. pengae; 4.02-4.10 in S. spinata; 3.44-4.50Etymology.The specific name is derived from the Latin word "papillatus" and refers to the presence of a papillary projection on the ventral face of the pedipalpal chela hand in male. Diagnosis.Carapace with four well-developed eyes, epistome triangular (Figs 9A, 10A, 11A, 12A).Male pedipalpal trochanter with a small process and small frosted projections on the median prolateral position; femur with several big tubercles and a projection on the prolateral position, a few small tubercles at the retrolateral surface; patella with a triangular protuberance on the prolateral position (Figs 9G, 10E); chelal hand concaved distally at the dorsal side, with 30-33 triangular spinous apophyses on the dorsal side and a papillary projection at the median of ventral side (Figs 9H, 10C).Male leg I femur and patella enlarged and basitarsus and telotarsus semi-fused (Figs 9I, 10F).Female pedipalpal fixed chelal finger with 99-102 teeth; pedipalpal femur 4.76-4.98times longer than wide.
Description.Adult male (holotype and male paratypes) (Figs 7A, 8A).Carapace (Figs 9A,10A).Carapace 1.23-1.36times longer than broad, with a total of 36-37 setae, including six near anterior margin and 6-7 near posterior margin; five lyrifissures near the eyes, four lyrifissures near posterior margin; epistome small, triangular, with rounded apex; four well-developed eyes; carapace divided into three parts by two transverse, shallow grooves, the anterior part uplifted, the median part with microgrooves, the posterior part uplifted and with microgrooves.
Pedipalps (Figs 9G, H, 10C, E).Apex of pedipalpal coxa rounded, with six long setae.Trochanter with a small process on the median prolateral position, as well as some small frosted projections; femur with several big tubercles on the prolateral position, as well as a projection on the subdistal prolateral surface, few small tubercles placed at the retrolateral surface; patella with a projection on the prolateral position and three lyrifissures (Figs 9G, 10E); chelal hand concaved at the dorsal side of distal half, and with 30-33 triangular-shaped, spinous apophyses on the dorsal side, every apophyse with a setae at the base (Figs 9H, 10C).A few spinous apophyses extended to the subbase of fixed finger.A papillary projection in the middle of the ventral aspect of the pedipalpal chelal hand.On the posterior side, a few small granular processes dispersedly located at the distal of the hand and near the base of the fingers.Fixed chelal finger slightly curved upward at median to distal part (Figs 9H, 10C).Trochanter 1.46-1.63,femur 4.48-5.02,patella 3.67-4.78,chela with pedicel 4.58-4.60,chela without pedicel 3.53-3.71times longer than broad, movable finger 1.68-1.84times longer than hand without pedicel.Fixed chelal finger with eight, movable chelal finger with four trichobothria: eb and esb situated on the base of hand, grouped very closely with ib and isb; est, et and it grouped distally; ist closer to est-et-ist than to isb-ib-esb-eb in fixed chelal finger; b and sb situated closer to each other in basal half, st and t close to each other in distal half of movable finger.Venom apparatus present only in fixed chelal finger, venom duct short.Fixed chelal finger with 93-105 pointed teeth, movable finger with 87-94 teeth, 34-42 rounded teeth at base, and 52-53 pointed ones.
Carapace (Figs 11A,12A).Carapace 1.04-1.13times longer than broad, with a total of 39-42 setae, including 5-6 near anterior margin and 8-9 near posterior margin; three lyrifissures near the eyes, two lyrifissures near posterior margin; carapace divided into three parts by two transverse, shallow grooves, the anterior part uplifted, the median part smooth, the posterior part uplifted, and with microgrooves.

Stenohya guangmingensis
Description.Adult male (holotype and male paratypes) (Figs 13A, 14B).Carapace (Figs 15A,16A).Carapace 1.08-1.16times longer than broad, with a total of 30-32 setae, including 5-6 near anterior margin and six near posterior margin; with six lyrifissures near the anterior eyes, four lyrifissures near posterior margin; epistome small, triangular, with rounded top; with four corneate eyes; the anterior half of the carapace uplifted and protruded to the sides, the front half significantly wider than the back part.
Remarks.The dividing line between basitarsus and telotarsus of the male leg I of this new species is usually indistinct in specimens examined, except for one paratype, which has this line slightly visible (Fig. 16I).There is no other distinct difference among these male specimens and, as a result, we consider this difference in the visibility of the dividing lines as intraspecific variation.

Discussion
In addition to sexually dimorphic pedipalp, the three new species described here a have uniquely sexual dimorphic leg I; that is, the femur and patella are enlarged or have an inward depression, and the basitarsus and telotarsus are fused or semi-fused in males.In particular, the male of S. gibba has a large columnar projection on the basitarsus and telotarsus of leg I, which has not been reported in other Stenohya species.According to Zhan et al. (2023) the three potential functions of the sexually dimorphic pedipalp are controlling the female during mating, attracting a female during courtship, or serving as a weapon in male-to-male competition.Given the proximity of the pedipalp and leg I, the specialized leg I may interact with the pedipalp in some manner while conducting any of these three potential functions.The discovery of new species enriches our knowledge of the morphological diversity of Stenohya pseudoscorpions.The various sexually dimorphic structures imply that Stenohya species may have differing adaptive methods under sexual or natural selection.

Figure 2 .
Figure 2. Type locality and habitus of Stenohya gibba sp.nov.A male habitus B female habitus C, D litter layer inhabited by habitus.

Figure 3 .
Figure 3. Holotype male of Stenohya gibba sp.nov.A carapace, dorsal view B right chelicera, dorsal view C rallum D galea E subterminal tarsal seta F chaetotaxy of genital area, ventral view G right pedipalp, dorsal view H right chela, lateral view, showing trichobothriotaxy, teeth and venom apparatus I right leg I, lateral view J right leg IV, lateral view K right leg I (basitarsus and telotarsus), retrolateral view.Scale bars: 0.5 mm (A, B, F, K); 0.1 mm (C-E); 1 mm (G-J).

Figure 4 .
Figure 4. Holotype male of Stenohya gibba sp.nov.A carapace, dorsal view (red arrows showing two transverse grooves) B right chelicera, dorsal view C right chela, lateral view D genital area, ventral view E right pedipalp, dorsal view F right leg I (basitarsus and telotarsus), prolateral view G right leg I (basitarsus and telotarsus), retrolateral view.H right leg I, lateral view I right leg IV, lateral view.Scale bars: 0.5 mm (A, B, D, F, G); 1 mm (C, E, H, I).

Figure 5 .
Figure 5. Paratype female of Stenohya gibba sp.nov.A carapace, dorsal view B right chelicera, dorsal view C rallum D galea E subterminal tarsal seta F chaetotaxy of genital area, ventral view G right pedipalp, dorsal view H right chela, lateral view, showing trichobothriotaxy, teeth and venom apparatus I right leg I, lateral view J right leg IV, lateral view.Scale bars: 0.5 mm (A, B, F); 0.1 mm (C-E); 1 mm (G-J).

Figure 6 .
Figure 6.Paratype female of Stenohya gibba sp.nov.A carapace, dorsal view (red arrow showing transverse groove) B right chelicera, dorsal view C right chela, lateral view D genital area, ventral view E right pedipalp, dorsal view F right leg I, lateral view G right leg IV, lateral view.Scale bars: 0.5 mm (A, B, D); 1 mm (C, E-G).

Figure 8 .
Figure 8. Type locality and habitus of Stenohya papillata sp.nov.A male habitus B female habitus C, D litter layer inhabited by habitus.

Figure 9 .
Figure 9. Holotype male of Stenohya papillata sp.nov.A carapace, dorsal view B right chelicera, dorsal view C rallum D galea E subterminal tarsal seta F chaetotaxy of genital area, ventral view G right pedipalp, dorsal view H right chela, lateral view, showing trichobothriotaxy, teeth and venom apparatus I right leg I, lateral view J right leg IV, lateral view.Scale bars: 0.5 mm (A, B, F); 0.1 mm (C-E); 1 mm (G-J).

Figure 10 .
Figure 10.Holotype male of Stenohya papillata sp.nov.A carapace, dorsal view (red arrows showing two transverse grooves) B right chelicera, dorsal view C right chela, lateral view D genital area, ventral view E right pedipalp, dorsal view F right leg I, lateral view G right leg IV, dorsal view.Scale bars: 0.5 mm (A, B, D); 1 mm (C, E-G).

Figure 11 .
Figure 11.Paratype female of Stenohya papillata sp.nov.A carapace, dorsal view B right chelicera, dorsal view C rallum D galea E subterminal tarsal seta F chaetotaxy of genital area, ventral view G right pedipalp, dorsal view H right chela, lateral view, showing trichobothriotaxy, teeth and venom apparatus I left leg I, lateral view J right leg IV, lateral view.Scale bars: 0.5 mm (A, B); 0.1 mm (C-E); 1 mm (F-J).

Figure 12 .
Figure 12.Paratype female of Stenohya papillata sp.nov.A carapace, dorsal view (red arrows showing two transverse grooves) B right chelicera, dorsal view C right chela, lateral view D genital area, ventral view E right pedipalp, dorsal view F left leg I, lateral view G right leg IV, lateral view.Scale bars: 0.5 mm (A, B); 1 mm (C-G).
80 times longer than broad, movable finger 1.74-2.02times longer than hand without pedicel.Fixed chelal finger with eight, movable chelal finger with four trichobothria: eb and esb situated on the base of hand, grouped very closely with ib and isb; est, et and it grouped distally; ist situated midway between isb and it; b and sb situated closer to each other in basal half, st and t close to each other in distal half of movable finger.Venom apparatus present only in fixed chelal finger, venom duct short.Fixed chelal finger with 97-99 pointed teeth, movable finger with 91-95 teeth, 45-57 rounded teeth at base, and 38-46 pointed ones.

Figure 14 .Figure 15 .
Figure 14.Type locality and habitus of Stenohya guangmingensis sp.nov.A male habitus B female habitus C-D litter layer inhabited by habitus.

Figure 16 .
Figure 16.Holotype and paratype male of Stenohya guangmingensis sp.nov.A-H holotype male I paratype male A carapace, dorsal view B right chelicera, dorsal view C right chela, lateral view D genital area, ventral view E right pedipalp, dorsal view F right leg I, lateral view G right leg IV, lateral view H right leg I (basitarsus and telotarsus), lateral view I right leg I (basitarsus and telotarsus), lateral view (paratype).Scale bars: 0.5 mm (A, D, F-I); 0.2 mm (B); 1 mm (C, E).

Figure 17 .
Figure 17.Paratype female of Stenohya guangmingensis sp.nov.A carapace, dorsal view B right chelicera, dorsal view C rallum D galea E subterminal tarsal seta F chaetotaxy of genital area, ventral view G right pedipalp, dorsal view H right chela, lateral view, showing trichobothriotaxy, teeth and venom apparatus I right leg I, lateral view J right leg IV, lateral view.Scale bars: 0.5 mm (A, D, F-H); 0.2 mm (B); 1 mm (C, E).

Figure 18 .
Figure 18.Paratype female of Stenohya guangmingensis sp.nov.A carapace, dorsal view B right chelicera, dorsal view C genital area, ventral view D right pedipalp, dorsal view E right chela, lateral view F right leg I, lateral view G right leg IV, lateral view.Scale bars: 0.5 mm (A, C, F, G); 0.2 mm (B); 1 mm (D, E).
times longer than broad, movable finger 1.98-2.35times longer than hand without pedicel.Fixed chelal finger with eight, movable chelal finger with four trichobothria: eb and esb situated on the base of hand, grouped very closely with ib and isb; est, et and it grouped distally; ist closer to est-et-it than to isb-ib-esb-eb in fixed chelal finger; b and sb situated closer to each other in basal half, st and t close to