Research Article
Print
Research Article
Chaerilus pseudoconchiformus sp. n. and an updated key of the chaerilid scorpions from China (Scorpiones, Chaerilidae)
expand article infoShijin Yin, Yanning Qiu§, Zhaohui Pan|, Shaobin Li, Zhiyong Di§
‡ South Central University for Nationalities, Wuhan, China
§ University of Science and Technology of China, Hefei, China
| Agriculture and Animal Husbandry College of Tibet University, Linzhi Region, Tibet, China
¶ Yangtze University, Jingzhou, China
Open Access

Abstract

A new species, C. pseudoconchiformus sp. n., is described from Xizang, China. The present new species is distinguished from its congeners by a body length of 32−40 mm, carapace with the anterior margin straight, chela with length/width ratio average of 3.3 in males (3.2−3.4, two adults), and 2.5 in females (2.3−2.6, nine adults), eight or nine (eight usually) rows of denticles on fixed and movable fingers of pedipalp chelae, five pectinal teeth in males and three or four in females. To date, the chaerilid species fauna of China consists of nine species. An updated identification key to Chaerilus from China is presented.

Keywords

Chaerilidae, Chaerilus, new species, Xizang, China

Introduction

The small monotypic family, Chaerilidae, has been reported containing one genus with 39 species (1/2015, http://www.ntnu.no/ub/scorpion-files/). The only genus is Chaerilus, which is found in southern and southeast Asia. In Xizang (Tibet), the chaerilid scorpions live under stones and fallen trees in humid habitats.

Chaerilid scorpions have a unique type B trichobothrial arrangement (Vachon 1974; Soleglad and Fet 2001). Kovařík (2000) reported 18 species in this genus in his review. Kovařík (2012) published an identification key for the genus. Recently, new species were described (Kovařík et al. 2014; Lourenço and Pham 2014).

Kovařík (2000) reported an old species and erected a new species of chaerilid from Xizang in his revision: C. pictus (Pocock, 1890) and C. tryznai Kovařík, 2000. In fact, one locality of C. tricostatus Pocock, 1899, Upper Rotung (Abor District), is also a territory belonging to Xizang (China). Therefore, Kovařík’s revision recorded three species for China (Di et al. 2009). Zhu et al. (2004) recorded one chaerilid species (C. pictus) found in China. Qi et al. (2005) described one new species (C. tessellatus Qi, Zhu & Lourenço, 2005) and redescribed C. pictus (misidentification). Bastawade (2006) reported a new species from southeast Xizang: C. dibangvalleycus Bastawade, 2006. Zhu et al. (2008) redescribed C. tessellatus and C. tryznai, and pointed out that C. pictus as redescribed by Qi et al. (2005) was misidentified and erected it as a new species: C. conchiformus Zhu, Han & Lourenço, 2008. Zhu et al. (2008) also suggested that distribution of C. pictus in China was doubtful. Di and Zhu (2009) reported one new species: C. mainlingensis Di & Zhu, 2009. Di et al. (2009) reviewed the genus Chaerilus in China, registered seven species, and described the female of C. tricostatus for the first time. Kovařík (2012) described a new species from Xizang: C. wrzecionkoi Kovařík, 2012. Di et al. (2014) reviewed the research history of the order Scorpiones from China, and recorded eight chaerilid species. To date, the chaerilid fauna of China consists of nine species including the new species described in this paper, C. pseudoconchiformus sp. n.

Material and methods

Illustrations and measurements were made using a Motic K700 stereomicroscope with an Abbe drawing tube and an ocular micrometer. The photos were taken with a Canon (650D) camera. Measurements follow Sissom (1990) and are given in mm. Trichobothrial notations follow Vachon (1974) and morphological terminology mostly follows Hjelle (1990). Research materials have been deposited in the Specimen Room of University of Science and Technology of China, Hefei, China (USTC).

Taxonomy

Family Chaerilidae Pocock, 1893
Genus Chaerilus Simon, 1877

Chaerilus pseudoconchiformus sp. n.

Figs 1–4, 5−25, 26–35, Tables 1, 2

Type material

Holotype, male, China: Xizang, Nyingchi County (Linzhi County), VIII/2014, Zhiyong Di and Tao Li leg. (Ar.-USTC-XZLZ1401); paratypes: 1 adult male, 9 adult females, same data as holotype (Ar.-USTC-XZLZ1402−11) (kept in USTC).

Diagnosis

The new species differs from its congeners by the following features: approximately 30−40 mm in total length (Table 2); carapace with the anterior margin straight; chela with length/width ratio: average of 3.3 in males, and 2.5 in females (Table 2); eight or nine (usually eight) rows of denticles on fixed and movable fingers of pedipalp chelae; five pectinal teeth in males and three or four in females. Chaerilus pseudoconchiformus sp. n. can be distinguished from the geographically and morphologically closely related species (Tables 23, and key). Morphologically closest are C. conchiformus and C. wrzecionkoi. Both these species have similar body lengths, as well as similar numbers of denticle rows on fixed and movable fingers of the pedipalp chelae. They can be distinguished by the length/width ratio of the pedipalp chela: manus of pedipalp in male narrow and long, chela length/width ratio in male higher than 3 (average of 3.3 in two males, and 2.5 in nine females) in C. pseudoconchiformus sp. n.; manus of pedipalp in male robust (Kovařík 2012: Fig. 68), chela length/width ratio in both sex adults lower than 2.6 in C. wrzecionkoi (Kovařík, 2012: 2); manus of pedipalp in both sex adults robust (Zhu et al. (2008): Figs 3, 17), chela length/width ratio in one male adult is 2.4 (paratype: Ar.–MHU–XZ0102), in two females (including the holotype) lower than 2.0 in C. conchiformus. Furthermore, C. pseudoconchiformus sp. n. has more slender pedipalps than C. wrzecionkoi (Table 1; Kovařík 2012: 13), in other words, the length ratio of pedipalp (LRP) is distinctly larger than the length ratio of total length (LRT) of C. pseudoconchiformus sp. n. and C. wrzecionkoi: 1.14 (LRP), 1.01 (LRT) in male holotypes; 1.08 (LRP), 0.95 (LRT) in female allotypes of C. pseudoconchiformus sp. n. and C. wrzecionkoi (Table 1).

Figures 1–4.

C. pseudoconchiformus sp. n., dorsal and ventral habitus: 1–2 Male holotype (Ar.−USTC−XZLZ1401) 3–4 Female paratype (Ar.−USTC−XZLZ1402). Scale bar = 10 mm.

Figures 5–25.

C. pseudoconchiformus sp. n. Male holotype: 5 Carapace, dorsal aspect 6 Lateral eyes area 7–8 Chelicera, dorsal and ventral aspects 11 Tegument of the seventh sternite; 12 Sternum, genital operculum and pectines 14–15 Metasomal segment V, lateral and ventral aspects 16 Telson 18–19 Femur, dorsal and external aspects 20–22 Patella, dorsal, external and ventral aspects. Female paratype (Ar.−USTC−XZLZ1402): 9–10 Chelicera, dorsal and ventral aspects 17 Telson 23–24 Femur, dorsal and external aspects 25 Patella, dorsal aspect. Scale bars = 2 mm.

Measurements (mm) of C. pseudoconchiformus sp. n., male holotype (Ar.-USTC-XZLZ1401) and female paratype (Ar.-USTC-XZLZ1402). The information of C. wrzecionkoi from Kovařík (2012).

C. pseudoconchiformus sp. n. C. wrzecionkoi
Male holotype Female paratype Male holotype Female paratype
Total length 37.4 37.1 37.0 39.0
Carapace:
-Length
-Anterior width
-Posterior width

4.5
2.4
5.0

4.4
2.7
5.3

4.3
4.4

4.5
5.1
Mesosomal segments:
-Length

11.3

13.5
Metasomal segment I:
-Length
-Width
-Depth

2.0
2.9
2.1

1.8
2.8
2.1

2.0
2.4

1.8
2.7
Metasomal segment II:
-Length
-Width
-Depth

2.6
2.4
1.9

2.2
2.4
1.8

2.4
2.0

2.2
2.2
Metasomal segment III:
-Length
-Width
-Depth

2.9
2.3
1.7

2.5
2.2
1.8

2.4
2.0

2.2
2.0
Metasomal segment IV:
-Length
-Width
-Depth

3.3
2.1
1.6

3.0
2.0
1.6

2.7
1.9

2.7
1.8
Metasomal segment V:
-Length
-Width
-Depth

5.4
1.9
1.5

4.9
1.8
1.5

4.7
1.8

4.4
1.6
Telson:
-Length
-Width
-Depth

5.5
2.1
1.7

4.8
2.0
1.7

4.9


4.9

Pedipalp femur:
-Length
-Width
-Depth

5.4
1.8
1.9

4.1
1.7
1.9

4.5
1.6

3.7
1.7
Pedipalp patella:
-Length
-Width
-Depth

5.3
1.9
2.1

4.1
2.0
2.4

4.8
1.7

4.0
2.2
Chela:
-Length
-Width (manus)
-Depth (manus)

10.2
3.2
3.1

9.0
3.6
3.1

9.0
3.5

8.3
3.5
Movable finger:
-Length

5.2

5.2

5.0

4.5
Pectinal teeth (left/right) 5/5 4/4 4/5 ?

Feature datasets of body length (BL, mm; segment by segment was measured and added in type specimens, while others were measured for overall length only), chela with length/width ratio (CR), number of granule rows of movable finger of pedipalp (RN), and number of pectinal teeth (PT) of C. conchiformus (CO, Ar.-USTC-XZLZ1412), C. pseudoconchiformus sp. n., and C. tryznai (TY, Ar.-USTC-XZBM1401−02).

Sex BL CR RN PT
XZLZ1401 37.4 3.2 8/8 5/5
XZLZ1402 37.1 2.5 8/8 4/4
XZLZ1403 32.0 3.4 8/8 5/5
XZLZ1404 36.0 2.5 8/8 4/4
XZLZ1405 39.0 2.6 9/9 4/4
XZLZ1406 32.5 2.4 8/8 3/3
XZLZ1407 38.0 2.6 8/8 4/3
XZLZ1408 37.0 2.3 8/8 3/3
XZLZ1409 38.0 2.3 8/8 3/3
XZLZ1410 37.0 2.5 8/8 4/3
XZLZ1411 35.5 2.5 8/8 4/3
XZLZ1412(CO) 32.0 1.9 7/7 4/4
XZBM1401(TY) 44.0 2.8 8/8 3/3
XZBM1402(TY) 39.0 2.6 8/8 3/3

The differences between chaerilids from China: C. conchiformus, C. dibangvalleycus, C. mainlingensis, C. pictus, C. pseudoconchiformus sp. n., C. wrzecionkoi, C. tessellatus, C. tricostatus, and C. tryznai; body length (BL, mm); carapace with the anterior margin (straight or curving, CA); chela with length/width ratio respectively in females and males (CR(F), CR(M)), dorsal secondary carinae of the chela (DS); rows number of denticles on fixed and movable fingers of chelae (RF); the tegument of the seventh sternite (SVII); holotype (H), paratype (P), new material (N).

conchiformus (H&N) dibangvalleycus (H&P) mainlingensis (H&P) pictus (H&P) pseudoconchiformus sp. n. (H&P) wrzecionkoi (H&P) tessellatus (H&P) tricostatus (N) tryznai (H, P&N)
BL 32−44 36−42 40−41 38−66 32–39 33−41 35−52 48−60 30–44
CA straight slightly curving slightly depressed slightly curving straight straight straight straight straight
CR(F) 1.8−1.9 ? 2.4−2.8 2.4 2.3−2.6 2.4 2.2 2.2−2.4 2.6−2.9
CR(M) ? ? ? 2.5 3.2−3.4 2.6 ? 3.7 >3
DS present absent absent present present present present absent present
RF 8 7 or 8 *1 7 13 or 14 8 or 9 8(9?) *2 11 11or 12 8
SVII weakly granular; with carinae granular; with carinae weakly granular; with carinae ? granular; without carinae granular; without carinae with carinae granular; with carinae granular; without carinae

Etymology

The specific name refers to the geographically and morphologically most closely related species C. conchiformus, adding the Greek prefix “pseudo−” as “pseudoconchiformus”, because the habitus of both sexes is very similar to that of C. conchiformus.

Description

Based on male holotype and female paratype.

Coloration (Figs 1–4). Basically reddish brown. Carapace dark red-brown with black parts and yellowish stripes. Mesosomal tergites dark red-brown with yellowish stripes. Metasoma: all segments dark red-brown. Telson dark red-brown with reddish brown part; aculeus light red-brown. Chelicerae reddish brown with dark reticular pattern on dorsal surface. Pedipalps: femur, patella and chela dark red-brown with dark carinae. Legs dark red-brown and red-brown on distal segments. Sternum, genital operculum and sternites red-brown with some light parts. Pectines light yellow.

Morphology. Carapace carinated, with the anterior margin straight; with dense granules of nearly equal size; lateral furrow moderately deep; large granules form 2 longitudinal lateral carinae (Fig. 5). Median ocular tubercle with granules. Lateral ocular tubercle small with a pair of lateral eyes and some granules (Fig. 6). Lateral eyes distinctly smaller than median eyes (Fig. 5).

Mesosoma: Tergites uniform distributing with granules of larger and unequal size; tergites I to II without carinae, each of tergites III to VI bearing a pairs of obsolete granular carinae on posterior margin, tergite VII bearing two pairs of obsolete granular lateral carinae, but middle pair is represented only by ridges without expressed carinae; sternum pentagonal; genital operculum triangular; pectinal teeth count 5/5 in males and 3−4 in females, with fulcra well developed (Figs 12–13); sternites III to VI are smooth, sternite VII granular without carinae (Fig. 11).

Metasoma: Length about 4.8 times as long as carapace in males and 4.4 in females; segment I always wider than long; segments I to V with 10-8-8-8-7 granular carinae; the ventromedian and ventrolateral carinae of segment V composed of strong, dentated granules, ventromedian carina posteriorly bifurcated as “Y” (Figs 14–15); all segments with sparse small granules. Vesicle is almost smooth; aculeus slightly curved (Figs 16–17).

Chelicerae: Tibia surfaces smooth; thickly covered with numerous short, silky hairs, extending to ventral aspect of chelicerae and dorsal aspect of fixed fingers; ventral inner edges of movable finger with some minute teeth (2−3 obsolete teeth in two males and 3−9 well developed and obsolete teeth in nine females) (Figs 7–10).

Pedipalp: Tegument granular. The femur has four carinae and the patella has five granular carinae (Figs 1827). Chela with length/width ratio average of 3.3 in males (two adults) and 2.5 in females (nine adults), has seven granulated dorsointernal, except internal carina obsolete; entire tegument of chela manus densely covered with coarse granules, forming some indistinct reticular pattern (Figs 28–33); fingers straight, the cutting edge of movable finger with 8 or 9 (mainly 8) rows of denticles (Figs 34–35). Trichobothriotaxy of type B; orthobothriotaxic (Vachon 1974) (Figs 1833).

Figures 26–35.

C. pseudoconchiformus sp. n. Male holotype: 28–30 Chela, dorsoexternal, ventral, and internal aspects 34 Movable finger of pedipalp. Female paratype (Ar.−USTC−XZLZ1402): 26–27 Patella, external and ventral aspects 31–33 Chela, dorsoexternal, ventral, and internal aspects 35 Movable finger of pedipalp. Scale bars = 2 mm.

Legs: Tibia without tibial spur. Basitarsus with two pedal spurs strongly developed. Tarsi with two rows of spiniform setae.

Variation

Coloration and morphology in holotype and paratypes are very similar (feature datasets please see Table 2).

Habitat

Found under the stones in mixed forest.

Distribution

China (Xizang).

Update key to species of the genus Chaerilus in China

1 Movable finger of pedipalp with 7–9 rows of granules 2
Movable finger of pedipalp with 10–14 rows of granules 7
2 Chela length to width ratio in female adults 1.6–1.9 C. conchiformus
Chela length to width ratio in female adults higher than 2.0 3
3 Ventral side of seventh mesosomal segment with 2 pairs of granular carinae; carapace with anterior margin straight with a median notch 4
Ventral side of seventh mesosomal segment with many granules but without carinae; carapace with anterior margin straight without median notch 5
4 Pedipalp femur shorter than carapace; 8–9 minute teeth on inner ventral margins of movable and immovable fingers respectively (Bastawade 2006: 451, fig. 5) C. dibangvalleycus
Pedipalp femur longer than carapace, 7–8 minute teeth on inner ventral margins of movable and immovable fingers respectively (Di and Zhu 2009: 101, fig. 11) C. mainlingensis
5 Manus of pedipalp narrower and longer with the ventral margin not round in females (Zhu et al. 2008: fig. 47); chela length/width ratio in females is 2.6–2.9 (Kovařík 2000: table 1) C. tryznai
Manus of pedipalp robust in females with the ventral margin very round in females; chela length/width ratio in females is 2.3–2.6 6
6 Chela length/width ratio in males average of 3.3 (3.2−3.4), and 2.5 in females (2.3−2.6), chelae of male and female with sexual dimorphism C. pseudoconchiformus sp. n.
Chela length/width ratio about 2.6 in male, and about 2.4 in female, chelae of male and female without sexual dimorphism (Kovařík 2012: 13, figs 62, 76) C. wrzecionkoi
7 Movable finger of pedipalp with 13–14 rows of granules; telson of male rather long and about 4.7 times longer than wide, with an obvious sexual dimorphism in both sexes C. pictus
Movable finger of pedipalp with 11–12 rows of granules; telsons of male and female without sexual dimorphism 8
8 Carapace and tergites nearly smooth in adults (Zhu et al. 2008: 44, 47) C. tessellatus
Carapace and tergites with many big granules in adults (Di et al. 2009: 133, 136) C. tricostatus

Acknowledgements

We are grateful to Profs. Victor Fet and Wilson R. Lourenço for providing references and linguistic improvement. Sincere appreciation goes to Mr. Tao Li for the help to collect specimens. This work was supported in part by grants from the Fundamental Research Funds for the Central Universities (WK2070000056), the National Natural Sciences Foundation of China (30900239 and 81373379) and the Ministry of Science and Technology of the People’s Republic of China (MOST grant no. 2014FY210200).

References

  • Bastawade DB (2006) Arachnida: Scorpionida, Uropygi, Schizomida and Oncopodid Opiliones (Chelicerata). Zool. Surv, India. Fauna of Arunachal Pradesh, State Fauna Series 13: 449−465.
  • Di ZY, Zhu MS (2009) A new species of Chaerilus Simon, 1877 (Scorpiones, Chaerilidae) from China. Acta Arachnologica 58: 97−102. doi: 10.2476/asjaa.58.97
  • Di ZY, Wu YL, Cao ZJ, Fan LQ, Li WX (2009) The genus Chaerilus Simon, 1877 (Scorpiones: Chaerilidae) in China, with a description of the female C. tricostatus Pocock, 1899. Arthropoda Selecta 18: 131−138.
  • Di ZY, Xu XB, Cao ZJ, Wu YL, Li WX (2013) Notes on the scorpions (Arachnida, Scorpiones) from Tibet with the redescription of Scorpiops jendeki Kovařík, 2000 (Scorpiones, Euscorpiidae) from Yunnan (China). ZooKeys 301: 51−99. doi: 10.3897/zookeys.301.4608
  • Di ZY, Yang ZZ, Yin SJ, Cao ZJ, Li WX (2014) History of study, updated checklist, distribution and key of scorpions (Arachnida: Scorpiones) from China. Zoological Research 35: 3−19.
  • Fet V (2000) Family Chaerilidae Pocock, 1893. In: Fet V, Sissom WD, Lowe G, Braunwalder M. Catalog of the Scorpions of the World (1758–1998). The New York Entomological Society, New York, 323−328.
  • Hjelle JT (1990) Anatomy and morphology. In: Polis GA (Ed.) The Biology of Scorpions. Stanford Univ. Press, 9–63.
  • Kovařík F (2000) Revision of family Chaerilidae (Scorpiones), with descriptions of three new species. Serket 7: 38−77.
  • Kovařík F (2012) Five new species of Chaerilus Simon, 1877 from China, Indonesia, Malaysia, Philippines, Thailand, and Vietnam (Scorpiones: Chaerilidae). Euscorpius 149: 1−14.
  • Kovařík F, Kral J, Korinkova T, Lerma ACR (2014) Chaerilus hofereki sp. n. from Vietnam (Scorpiones: Chaerilidae). Euscorpius 189: 1−11.
  • Lourenço WR (2012) More about the genus Chaerilus Simon, 1877 in Vietnam and Cambodia, with descrptions of two new species. Arthropoda Selecta 21: 235−241.
  • Lourenço WR, Pham DS (2014) The genus Chaerilus Simon, 1877 in Vietnam (Scorpiones; Chaerilidae): A possible case of a vicariant species. Comptes Rendus-Biologies 337: 360−364. doi: 10.1016/j.crvi.2014.04.001
  • Qi JX, Zhu MS, Lourenço WR (2005) Eight new species of the genera Scorpiops Peters, Euscorpiops Vachon, and Chaerilus Simon (Scorpiones: Euscorpiidae, Chaerilidae) from Tibet and Yunnan, China. Euscorpius 32: 1–40.
  • Sissom WD, Polis GA, Watt DD (1990) Field and laboratory methods. In: Polis GA (Ed.) The Biology of Scorpions. Stanford University Press, Stanford, California, 445–461.
  • Vachon M (1974) Etude des caracteres utilises pour classer les familles et les genres de Scorpions (Arachnides). 1. La trichobothriotaxie en arachnologie. Sigles trichobothriaux et types de trichobothriotaxie chez les Scorpions. Bulletin du Museum national d’Histoire naturelle, Paris, 3e ser., 140: 857–958.
  • Zhu MS, Han GX, Lourenço WR (2008) The chaerilid scorpions of China (Scorpiones: Chaerilidae). Zootaxa 1943: 37−52.
  • Zhu MS, Qi JX, Song DX (2004) A Checklist of Scorpions from China (Arachnida: Scorpiones). Acta Arachnologica Sinica 13: 111–118.