Research Article |
Corresponding author: Yun-Chun Li ( liyunchun2260@126.com ) Academic editor: Jason Dunlop
© 2022 Yun-Chun Li.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Li Y-C (2022) Five new troglobitic species of Tyrannochthonius (Arachnida, Pseudoscorpiones, Chthoniidae) from the Yunnan, Guizhou and Sichuan Provinces, China. ZooKeys 1131: 173-195. https://doi.org/10.3897/zookeys.1131.91235
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Five new species of the genus Tyrannochthonius Chamberlin, 1929 are described from caves in the provinces of Yunnan (T. huilongshanensis sp. nov., T. xinzhaiensis sp. nov., and T. yamuhensis sp. nov.), Guizhou (T. dongjiensis sp. nov.), and Sichuan (T. huaerensis sp. nov.). An identification key is provided for all known representatives of the genus Tyrannochthonius from China.
Cave-inhabiting, identification key, pseudoscorpion, soil-dwelling, taxonomy
The pseudoscorpion tribe Tyrannochthoniini Chamberlin, 1962 belongs to the subfamily Chthoniinae Daday, 1889 and the family Chthoniidae Daday, 1889. It is distributed on all continents except Antarctica and contains six genera: Lagynochthonius Beier, 1951; Maorichthonius Chamberlin, 1925; Paraliochthonius Beier, 1956; Troglochthonius Beier, 1939; Tyrannochthonius Chamberlin, 1929; and Vulcanochthonius Muchmore, 2001 (
The pseudoscorpion genus Tyrannochthonius was erected by Chamberlin for the Thai type species Chthonius terribilis With, 1906 (by original designation) (
The specimens were preserved in 75% ethanol. They were cleared in lactic acid for 12–24 h at room temperature and, after the study, washed in distilled water and returned to alcohol. The specimens were examined with a Leica M205FA stereomicroscope and an Olympus CX31 compound microscope. Photographs were taken using a Canon 6D Mark II camera fitted with Laowa 25 mm f/2.8 2.5–5X and 100 mm F2.8 2.0X Ultra Macro lenses. The final high depth-of-field (DoF) images were stacked from 30 to 80 single photos using Helicon Focus 7.6.1., and CorelDRAW 2018 and SAI 2 softwares were used to draw the figures. The type specimens of the new species are deposited in the collection of the Museum of China West Normal University (MCWNU; Sichuan, China).
Pseudoscorpion terminology and measurements mostly follow
Family Chthoniidae Daday, 1889
Subfamily Chthoniinae Daday, 1889
Tribe Tyrannochthoniini Chamberlin, 1962
Genus Tyrannochthonius Chamberlin, 1929
Holotype male: China, Guizhou Province, Luodian County, Dongjia Town, Dongjia Village, Nameless Cave, 25°38.53'N, 106°54.67'E, 869 m a.s.l., 7 October 2019, Yun-Chun Li leg., in MCWNU (Ar-Ps-GZ-0055). Paratypes: 2 males, 4 females, collected with the holotype, in MCWNU (Ar-Ps-GZ-0008); 5 males, 2 females, Guizhou Province, Pingtang County, Tangbian Town, Baima Cave, 25°40'6.13"N, 106°45'53.89"E, 870 m a.s.l., 6 October 2019, Yun-Chun Li leg., in MCWNU (Ar-Ps-GZ-0010).
Troglobiont habitus. This new species is distinguished from other members of the genus Tyrannochthonius by the following combination of characters: carapace without eyes or eyespots, anterior margin with six setae; epistome absent; rallum composed of six blades; tergites I–IV with two setae; apex of coxa I with long and rounded anteromedial process, near the apex with a seta; chelal hand dorsal surface with chemosensory setae; fixed chelal finger with 24 or 25 teeth, movable chelal finger with 27–29 retrorse teeth. Pedipalpal femur (♂) 7.58–7.63×, (♀) 7.36–7.42× longer than broad, length (♂) 0.91–0.95 mm, (♀) 1.03–1.07 mm; chela (♂) 7.88–7.90×, (♀) 7.06–7.10 longer than deep, length (♂) 1.25–1.28 mm, (♀) 1.20–1.24 mm; ratio movable chelal finger/chelal hand (♂) 1.86–1.90×, (♀) 1.88–1.93×.
Latinized adjective, derived from the village of Dongjia, located near the type locality.
Adult male (Fig.
Pale yellow-orange, chelicera slightly darker, soft parts pale (Fig.
Carapace
(Fig.
Tyrannochthonius dongjiensis sp. nov., holotype male (A–K) and paratype female (L) A carapace B left chelicera C rallum of left chelicera D coxal spines E process of left coxa I, ventral view F left leg I, lateral view G left leg IV, lateral view H palp (minus chela) I chela, retrolateral view J chela, dorsal view K male genital area L female genital area. Scale bars: 0.20 mm
Adult female (Fig.
Mostly the same as the holotype with the differences listed below.
Carapace
: slightly longer than broad (1.13–1.15×). Chelicera: 2.30–2.33× longer than broad. Pedipalp: trochanter 1.80–1.86× longer than broad, femur 7.36–7.42× longer than broad, patella 2.63–2.70× longer than broad, femur 2.45–2.49× longer than patella. Chela 7.06–7.10× longer than deep, hand 2.41–2.46× longer than deep; movable finger 1.88–1.93× longer than hand. Opisthosoma: tergal chaetotaxy (I–XII): 2: 2: 2: 2: 4: 4: 4: 4: 4: 2: 2: 0; sternal chaetotaxy (IV–XII): 14: 12: 8: 7: 7: 9: 7: 0: 2. Anterior genital operculum with 9 + 14 setae on posterior margin (Fig.
Dimensions (mm, length/width or, in the case of the legs, chela, and chelal hand, length/depth).
Males (females in parentheses): body length 2.24–2.30 (2.49–2.56). Carapace 0.54–0.57/0.43–0.45 (0.53–0.55/0.47–0.48). Pedipalp: trochanter 0.25–0.28/0.16–0.18 (0.27–0.29/0.15–0.17), femur 0.91–0.95/0.12–0.14 (1.03–1.07/0.14–0.16), patella 0.41–0.44/0.15–0.17 (0.42–0.44/0.16–0.18), hand 0.42–0.45/0.16–0.17 (0.41–0.44/0.17–0.18), length of movable chelal finger 0.78–0.80 (0.77–0.79), chela 1.25–1.28/0.16–0.17 (1.20–1.24/0.17–0.18). Chelicera: 0.51–0.53/0.28–0.29 (0.53–0.55/0.23–0.24). Leg I: trochanter 0.15–0.17/0.15–0.16 (0.15–0.17/0.14–0.16), femur 0.61–0.64/0.08–0.09 (0.62–0.65/0.08–0.09), patella 0.32–0.35/0.07–0.08 (0.31–0.34/0.07–0.08), tibia 0.26–0.27/0.06–0.07 (0.27–0.29/0.06–0.07), tarsus 0.67–0.69/0.05–0.06 (0.66–0.68/0.05–0.06). Leg IV: trochanter 0.15–0.17/0.17–0.18 (0.17–0.19/0.14–0.16), femoropatella 0.88–0.92/0.23–0.25 (0.90–0.93/0.22–0.24), tibia 0.62–0.65/0.09–0.10 (0.63–0.65/0.09–0.10), basitarsus 0.30–0.32/0.08–0.09 (0.29–0.31/0.08–0.09), telotarsus 0.76–0.79/0.05–0.06 (0.79–0.82/0.06–0.07).
China (Guizhou).
Holotype male: China, Sichuan Province, Luzhou City, Gulin County, Shipping Town, Xiangding Village, Huaer Cave, 28°02.22'N, 106°01.43'E, 760 m a.s.l., 3 November 2019, Yun-Chun Li leg., in MCWNU (Ar-Ps-SC-0052). Paratypes: 4 males, 2 females, collected with the holotype, in MCWNU (Ar-Ps-SC-0001).
Troglobiont habitus. This new species is distinguished from other members of the genus Tyrannochthonius by the following combination of characters: carapace without eyes or eyespots, anterior margin with four setae; epistome very small; rallum composed of eight blades; tergites I–VI with four setae; chelal finger without intercalary teeth; coxae II with 12 terminally indented coxal spines on each side; chelal hand dorsal surface with chemosensory setae; apex of coxa I with long and rounded anteromedial process, near the apex without setae; movable finger retrolateral margins weakly curved between st and sb trichobothria; fixed chelal finger with 23 or 24 teeth, movable chelal finger with 14 or 15 macrodenticles and 7–9 vestigial teeth. Pedipalpal femur (♂) 8.92–8.95×, (♀) 8.54–8.59× longer than broad, length (♂) 1.16–1.19 mm, (♀) 1.11–1.17 mm; chela (♂) 7.00–7.07×, (♀) 8.67–8.69× longer than deep, length (♂) 1.61–1.64 mm, (♀) 1.56–1.58 mm; ratio movable chelal finger/chelal hand (♂) 1.56–1.59×, (♀) 1.52–1.55×.
Latinized adjective, derived from the type locality, namely Huaer Cave.
Adult male (Fig.
Carapace, chelicera, pedipalps, and tergites I–VI reddish brown, remaining parts yellowish brown (Fig.
Carapace
(Fig.
Tyrannochthonius huaerensis sp. nov., holotype male (A–H) and paratype female (I) A carapace B right chelicera C rallum of left chelicera D process of left coxa I, ventral view E palp (minus chela) F chela, retrolateral view G chela, dorsal view H male genital area I female genital area. Scale bars: 0.20 mm.
Adult female (Fig.
Mostly the same as the holotype with the differences listed below.
Carapace
: slightly longer than broad (1.08–1.10×). Chelicera: 2.27–2.29× longer than broad. Pedipalp: trochanter 1.81–1.84× longer than broad, femur 8.54–8.59× longer than broad, patella 2.87–2.89× longer than broad, femur 2.58–2.60× longer than patella. Chela 8.67–8.69× longer than deep, hand 3.44–3.47× longer than deep; movable finger 1.52–1.55× longer than hand. Opisthosoma: tergal chaetotaxy (I–XII): 4: 4: 4: 4: 4: 4: 4: 4: 5: 4: 2: 0; sternal chaetotaxy (IV–XII): 10: 9: 9: 8: 10: 10: 8: 0: 2. Anterior genital operculum with 10 + 6 setae on posterior margin (Fig.
Dimensions (mm, length/width or, in the case of the legs, chela, and chelal hand, length/depth).
Males (females in parentheses): body length 1.89–1.95 (1.87–1.99). Carapace 0.59–0.60/0.53–0.54 (0.53–0.55/0.49–0.51). Pedipalp: trochanter 0.20–0.22/0.16–0.18 (0.29–0.30/0.16–0.17), femur 1.16–1.19/0.13–0.15 (1.11–1.17/0.13–0.15), patella 0.44–0.45/0.16–0.17 (0.43–0.44/0.15–0.16), hand 0.63–0.65/0.23–0.25 (0.62–0.65/0.18–0.20), length of movable chelal finger 0.98–0.99 (0.94–0.97), chela 1.61–1.64/0.23–0.25 (1.56–1.58/0.18–0.20). Chelicera: 0.60–0.61/0.26–0.28 (0.59–0.60/0.26–0.27). Leg I: trochanter 0.19–0.20/0.12–0.14 (0.19–0.21/0.12–0.14), femur 0.66–0.69/0.08–0.09 (0.57–0.59/0.08–0.09), patella 0.33–0.35/0.07–0.08 (0.30–0.32/0.07–0.08), tibia 0.29–0.30/0.07–0.08 (0.29–0.30/0.06–0.07), tarsus 0.67–0.69/0.06–0.07 (0.65–0.67/0.05–0.06). Leg IV: trochanter 0.23–0.25/0.20–0.21 (0.17–0.19/0.14–0.16), femoropatella 0.90–0.92/0.27–0.29 (0.83–0.86/0.25–0.27), tibia 0.67–0.69/0.10–0.11 (0.62–0.64/0.10–0.11), basitarsus 0.30–0.32/0.08–0.09 (0.27–0.29/0.08–0.09), telotarsus 0.76–0.79/0.06–0.07 (0.70–0.74/0.05–0.06).
China (Sichuan).
Holotype male: China, Yunnan Province, Dali City, Nanjian County, Xiaowan Town, Huilongshan Village, Banpoyan Cave, 24°56.01'N, 100°18.87'E, 1990 m a.s.l., 23 August 2018, Yun-Chun Li leg., in MCWNU (Ar-Ps-YN-0079). Paratypes: 2 males, 7 females, collected with the holotype, in MCWNU (Ar-Ps-YN-0012).
Troglobiont habitus. This new species is distinguished from other members of the genus Tyrannochthonius by the following combination of characters: carapace without eyes or eyespots, anterior margin with four- setae; epistome present; tergites I–V with four setae; coxae II with eight terminally indented coxal spines on each side; apex of coxa I with long and rounded anteromedial process, near the apex with a seta; chelal hand dorsal surface with chemosensory setae; fixed chelal finger with 28 teeth and 16 or 17 intercalary teeth, movable chelal finger with 15 or 16 macrodenticles, 12 or 13 intercalary teeth and 5–7 vestigial teeth. Pedipalpal femur (♂) 4.87–4.90×, (♀) 5.33–5.37× longer than broad, length (♂) 0.73–0.76 mm, (♀) 0.80–0.83 mm; chela (♂) 5.61–5.66×, (♀) 6.37–6.40× longer than deep, length (♂) 1.01–1.09 mm, (♀) 1.21–1.25 mm; ratio movable chelal finger/chelal hand (♂) 1.75–1.80×, (♀) 1.80–1.83×.
Latinized adjective, derived from the village of Huilongshan, which is near the type locality.
Adult male (Fig.
Chelicera reddish brown, remaining parts yellowish brown (Fig.
Carapace
(Fig.
Adult female (Fig.
Mostly the same as the holotype with the differences listed below.
Carapace
: slightly longer than broad (0.90–0.99×). Chelicera: 2.13–2.17× longer than broad. Pedipalp: trochanter 1.86–1.88× longer than broad, femur 5.33–5.37× longer than broad, patella 1.94–1.98× longer than broad, femur 2.58–2.59× longer than patella. Chela 6.37–6.40× longer than deep, hand 2.11–2.15× longer than deep; movable finger 1.80–1.83× longer than hand. Opisthosoma: tergal chaetotaxy (I–XII): 4: 4: 4: 4: 5: 6: 6: 6: 5: 4: 2: 0; sternal chaetotaxy (IV–XII): 12: 10: 7: 8: 7: 7: 6: 0: 2. Anterior genital operculum with 10 + 17 setae on posterior margin (Fig.
Dimensions (mm, length/width or, in the case of the legs, chela, and chelal hand, length/depth).
Males (females in parentheses): body length 1.68–1.75 (1.89–1.95). Carapace 0.44–0.46/0.43–0.44 (0.45–0.49/0.50–0.51). Pedipalp: trochanter 0.24–0.26/0.15–0.17 (0.26–0.28/0.14–0.16), femur 0.73–0.76/0.15–0.17 (0.80–0.83/0.15–0.17), patella 0.29–0.31/0.18–0.19 (0.31–0.33/0.16–0.17), hand 0.36–0.40/0.18–0.20 (0.40–0.44/0.19–0.20), length of movable chelal finger 0.63–0.67 (0.72–0.76), chela 1.01–1.09/0.18–0.20 (1.21–1.25/0.19–0.20). Chelicera: 0.45–0.47/0.20–0.22 (0.51–0.54/0.24–0.26). Leg I: trochanter 0.17–0.19/0.10–0.11 (0.16–0.18/0.14–0.15), femur 0.39–0.42/0.06–0.07 (0.45–0.46/0.08–0.09), patella 0.25–0.27/0.06–0.07 (0.28–0.30/0.07–0.08), tibia 0.20–0.22/0.05–0.06 (0.22–0.25/0.06–0.07), tarsus 0.42–0.45/0.05–0.06 (0.49–0.53/0.05–0.06). Leg IV: trochanter 0.16–0.17/0.16–0.17 (0.21–0.22/0.15–0.17), femoropatella 0.57–0.59/0.22–0.24 (0.54–0.57/0.20–0.22), tibia 0.44–0.46/0.10–0.11 (0.43–0.46/0.11–0.12), basitarsus 0.19–0.21/0.07–0.08 (0.21–0.23/0.08–0.09), telotarsus 0.48–0.50/0.05–0.06 (0.50–0.54/0.05–0.06).
China (Sichuan).
Holotype male: China, Yunnan Province, Zhaotong City, Zhenxiong County, Wude Town, Xinzhai Village, Daguoquan Cave, 27°35.90'N, 104°46.25'E, 1301 m a.s.l., 8 April 2017, Yun-Chun Li leg., in MCWNU (Ar-Ps-YN-0080). Paratypes: 1 male, 6 females, 6 tritonymphs, collected with the holotype, in MCWNU (Ar-Ps-YN-0007).
Troglobiont habitus. This new species is distinguished from other members of the genus Tyrannochthonius by the following combination of characters: carapace without eyes or eyespots, anterior margin with five or six setae; epistome present; tergites V–X with four setae; coxae II with 12 terminally indented coxal spines on each side; apex of coxa I with long and rounded anteromedial process, near the apex without setae; chelal hand dorsal surface with chemosensory setae; fixed chelal finger with 26 teeth, movable chelal finger with 34 or 35 teeth. Pedipalpal femur (♂) 6.94–6.97×, (♀) 6.71–6.77× longer than broad, length (♂) 1.18–1.21 mm, (♀) 1.14–1.18 mm; chela (♂) 7.90–7.91×, (♀) 6.44–6.42× longer than deep, length (♂) 1.66–1.68 mm, (♀) 1.61–1.64 mm; ratio movable chelal finger/chelal hand (♂) 1.61–1.64×, (♀) 1.76–1.80×.
Latinized adjective, derived from the village of Xinzhai, located near the type locality.
Adult male (Fig.
Carapace and chelicera reddish brown, remaining parts yellowish brown (Fig.
Carapace
(Fig.
Tyrannochthonius xinzhaiensis sp. nov., holotype male (A–H) and paratype female (I) A carapace B right chelicera C rallum of left chelicera D process of left coxa I, ventral view E palp (minus chela) F chela, retrolateral view G chela, dorsal view H male genital area I female genital area. Scale bars: 0.20 mm.
Adult female (Fig.
Mostly the same as the holotype with the differences listed below.
Carapace
: slightly longer than broad (1.00–1.02×). With 18 setae, including six on the anterior margin and two on the posterior margin. Chelicera: 2.26–2.27× longer than broad. Pedipalp: trochanter 1.82–1.86× longer than broad, femur 6.71–6.77× longer than broad, patella 1.76–1.79× longer than broad, femur 3.08–3.12× longer than patella. Chela 6.44–6.42× longer than deep, hand 2.20–2.22× longer than deep; movable finger 1.76–1.80× longer than hand. Opisthosoma: tergal chaetotaxy (I–XII): 4: 4: 3: 3: 4: 4: 4: 4: 4: 4: 2: 0; sternal chaetotaxy (IV–XII): 14: 10: 9: 9: 9: 9: 7: 0: 2. Anterior genital operculum with 9 + 6 setae on posterior margin (Fig.
Dimensions (mm, length/width or, in the case of the legs, chela, and chelal hand, length/depth).
Males (females in parentheses): body length 2.76–2.85 (2.69–2.88). Carapace 0.59–0.61/0.60–0.61 (0.58–0.60/0.58–0.59). Pedipalp: trochanter 0.25–0.26/0.16–0.17 (0.31–0.34/0.17–0.19), femur 1.18–1.21/0.17–0.19 (1.14–1.18/0.17–0.19), patella 0.44–0.46/0.24–0.26 (0.37–0.40/0.21–0.23), hand 0.61–0.63/0.21–0.22 (0.55–0.58/0.25–0.26), length of movable chelal finger 0.98–1.00 (0.97–1.01), chela 1.66–1.68/0.21–0.22 (1.61–1.64/0.25–0.26). Chelicera: 0.70–0.73/0.27–0.29 (0.61–0.64/0.27–0.29). Leg I: trochanter 0.20–0.22/0.14–0.15 (0.16–0.18/0.14–0.15), femur 0.66–0.68/0.10–0.11 (0.62–0.65/0.08–0.09), patella 0.37–0.39/0.09–0.10 (0.31–0.34/0.06–0.07), tibia 0.31–0.32/0.08–0.09 (0.31–0.33/0.06–0.07), tarsus 0.67–0.69/0.07–0.08 (0.64–0.67/0.06–0.07). Leg IV: trochanter 0.21–0.23/0.20–0.21 (0.19–0.21/0.17–0.19), femoropatella 0.92–0.95/0.24–0.26 (0.83–0.86/0.22–0.24), tibia 0.65–0.67/0.11–0.12 (0.57–0.60/0.09–0.10), basitarsus 0.30–0.31/0.08–0.09 (0.27–0.29/0.07–0.08), telotarsus 0.73–0.75/0.06–0.07 (0.68–0.70/0.05–0.06).
China (Yunnan).
Holotype male: China, Yunnan Province, Lushui City, Fugong County, Shiyueliang Town, Lishadi Village, Yamu River, Nameless Cave, 27°07.69'N, 98°51.61'E, 1500 m a.s.l., 18 August 2018, Yun-Chun Li leg., in MCWNU (Ar-Ps-YN-0078). Paratypes: 1 male, collected with the holotype, in MCWNU (Ar-Ps-YN-0014).
(male, female unknown). Troglobiont habitus. This new species is distinguished from other members of the genus Tyrannochthonius by the following combination of characters: carapace without eyes or eyespots, anterior margin with four setae; epistome present; tergites II–VI with four setae; coxae II with ten terminally indented coxal spines on each side; apex of coxa I with long and rounded anteromedial process, near the apex with a seta; chelal hand dorsal surface with chemosensory setae. Fixed chelal finger with 25 teeth and 20 intercalary teeth, movable chelal finger with 22–24 teeth and three or four intercalary teeth. Pedipalpal femur 6.06–6.07× longer than broad, length 0.97–0.99 mm; chela 7.63–7.66× longer than deep, length 1.45–1.46 mm; ratio movable chelal finger/chelal hand 1.91–1.92×.
Latinized adjective, derived from the river of Yamuhe, which is near the type locality.
Adult male (Fig.
Chelicera reddish brown, carapace and opisthosoma brown, remaining parts yellowish brown (Fig.
Carapace
(Fig.
Dimensions (mm, length/width or, in the case of the legs, chela, and chelal hand, length/depth).
Males: body length 2.25–2.30. Carapace 0.56–0.57/0.53–0.54. Pedipalp: trochanter 0.14–0.15/0.14–0.15, femur 0.97–0.99/0.16–0.18, patella 0.38–0.39/0.16–0.17, hand 0.47–0.49/0.19–0.20, length of movable chelal finger 0.90–0.92, chela 1.45–1.46/0.19–0.20. Leg I: trochanter 0.18–0.19/0.13–0.15, femur 0.53–0.55/0.08–0.09, patella 0.30–0.31/0.07–0.08, tibia 0.26–0.28/0.05–0.06, tarsus 0.59–0.60/0.05–0.06. Leg IV: trochanter 0.18–0.20/0.17–0.18, femoropatella 0.75–0.77/0.25–0.26, tibia 0.57–0.59/0.10–0.11, metatarsus 0.24–0.25/0.08–0.09, tarsus 0.64–0.66/0.05–0.06.
China (Yunnan).
1 | Carapace with eyes | 2 |
– | Carapace without eyes or eyespots | 4 |
2 | Chelal finger without intercalary teeth | 3 |
– | Chelal finger with intercalary teeth | T. robustus Beier, 1951 |
3 | Carapace with 18 setae; tergites VIII–IX each with 8 setae | T. japonicus (Ellingsen, 1907) |
– | Carapace with 16 setae; tergites VIII–IX each with 6 setae | T. pachythorax Redikorzev, 1938 |
4 | Chelal finger with intercalary teeth | 5 |
– | Chelal finger without intercalary teeth | 11 |
5 | Intercalary teeth only present on chelal finger | 6 |
– | Intercalary teeth present on both chelal fingers | 7 |
6 | Rallum with 6 pinnate blades; coxae II with 5 or 6 terminally indented coxal spines on each side; epistome present | T. zhai Gao, Zhang & Chen, 2020 |
– | Rallum with 7 or 8 pinnate blades; coxae II with 7 terminally indented coxal spines on each side; epistome absent | T. chixingi Gao, Wynne & Zhang, 2018 |
7 | Carapace anterior margin with 6 setae; chemosensory setae absent | 8 |
– | Carapace anterior margin with 4 setae; chemosensory setae present | 10 |
8 | Tergites I–II each with 2 setae | 9 |
– | Tergites I–II each with 4 setae | T. antridraconis Mahnert, 2009 |
9 | Palpal femur 6.60× as long as broad (length 0.90 mm), chela 7.70× longer than deep | T. akaleus Mahnert, 2009 |
– | Palpal femur 5.90–6.70× as long as broad (length 0.95–0.97 mm), chela 6.90–7.30× longer than deep | T. ganshuanensis Mahnert, 2009 |
10 | Coxae II with 8 terminally indented coxal spines on each side ; chela 5.61–5.66× longer than deep | huilongshanensis sp. nov. |
– | Coxae II with 10 terminally indented coxal spines on each side; chela 7.63–7.66× longer than deep | T. yamuhensis sp. nov. |
11 | Chelal fingers straight in dorsal view | 12 |
– | Chelal fingers gently curved in dorsal view | T. pandus Hou, Gao & Zhang, 2022 |
12 | Chelal movable fingers without retrorse teeth; epistome present | 13 |
– | Chelal movable fingers with retrorse teeth; epistome absent | T. dongjiensis sp. nov. |
13 | Carapace anterior margin with 4 setae | 14 |
– | Carapace anterior margin with 5 or 6 setae | T. xinzhaiensis sp. nov. |
14 | Coxae II with 8 terminally indented coxal spines on each side; rallum with 6 pinnate blades | T. harveyi Gao, Zhang & Chen, 2020 |
– | Coxae II with 12 terminally indented coxal spines on each side; rallum with 8 pinnate blades | T. huaerensis sp. nov. |
There are 146 known species of Tyrannochthonius, including four subspecies, of which 52 species live in caves. Other than China, these cave species are distributed in Africa, Oceania, and North America. Among them, there are 31 species in the United States, five species in Australia, four species in Mexico, one species in Kenya, one species in New Caledonia, one species in Guatemala, one species in Peru, and one species in Jamaica (
In China, ten species and one subspecies have been recorded (Fig.
Known distribution of genus Tyrannochthonius from China. 1 T. akaleus; 2 T. antridraconis; 3 T. chixingi; 4 T. dongjiensis sp. nov.; 5 T. ganshuanensis; 6 T. harveyi; 7 T. huaerensis sp. nov.; 8 T. huilongshanensis sp. nov.; 9 T. japonicus; 10 T. pachythorax; 11 T. pandus; 12 T. robustus; 13 T. xinzhaiensis sp. nov.; 14 T. yamuhensis sp. nov.; 15 T. zhai.
The five new cave-dwelling species are easily distinguished from the seven known species: the chelal fingers of all new species are straight in dorsal view, while in T. pandus they are slightly curved. The movable finger of T. dongjiensis sp. nov. has retrorse teeth, which is similar to that of T. zhai, but the new species have a carapace with 18 setae and tergites I–IV each with two setae; the latter carapace only with 16 setae, and tergites I–IV each with four setae. There are only 16 setae on the carapace of T. chixingi, the other species have 17 or 18 setae. T. huaerensis sp. nov., T. huilongshanensis sp. nov., T. xinzhaiensis sp. nov., and T. yamuhensis sp. nov. are different from the remaining species (except T. antridraconis) in that the new species have tergites I-II each with three or four setae, while the latter only has two setae. In the new species, the chelal hand presents chemosensory setae on the dorsum, while in T. antridraconis they are absent. T. huilongshanensis sp. nov. and T. yamuhensis sp. nov. have intercalary teeth, the former with ten coxal spines and chela 7.63–7.66× longer than broad; in the latter, with eight coxal spines and chela 5.61–5.66× longer than broad. In T. huaerensis sp. nov., the anterior margin of the carapace with four setae, a slender and pointed epistome, palpal femur 8.92–8.95× as long as broad, and movable finger retrolateral margins weakly curved between st and sb trichobothria; in contrast, in T. xinzhaiensis sp. nov. the anterior margin of the carapace with five or six setae, epistome very small, palpal femur 6.94–6.97× as long as broad, movable finger retrolateral margins straight between st and sb trichobothria. In the known species, the chemosensory setae on the dorsal surface of the chelal hand are absent, while in the new species, there is a row of five to seven setae on the dorsal surface of the chelal hand.
Many thanks to Prof. Mark Harvey (Western Australian Museum, Perth, Australia) and an anonymous reviewer for comments that improved the manuscript. This study was supported by the Doctoral Scientific Research Foundation of China West Normal University (18Q043).