Chaerilus tessellatus Qi, Zhu et Lourenço, 2005

Qi, Jian-Xin, Zhu, Ming-Sheng & Lourenço, Wilson R., 2005, Eight new species of the genera Scorpiops Peters, Euscorpiops Vachon, and Chaerilus Simon (Scorpiones: Euscorpiidae, Chaerilidae) from Tibet and Yunnan, China, Euscorpius 32 (32), pp. 1-40 : 30

Chaerilus tessellatus Qi, Zhu et Lourenço , sp. n.

( Figs. 109–125 )

Diagnosis: The new species is of moderate size and smooth median ocular tubercles with a pair of small median eyes, which are almost as large as lateral eyes ( Fig. 118 ). The new species also has two pairs of dentated carinae on sternites V. Mesosomal tergites carinated, with a pair of median circular spots and transverse yellow spots ( Fig. 109 ).

Comments. Chaerilus tessellatus sp. n., can be distinguished from other Chaerilus species, and in particular from Chaerilus truncatus Karsch, 1879 , the most geographically close species of the genus, by the following features: (a) basal segment of chelicerae is not lustrous but without granules on dorsal surface; (b) lateral eye tubercles are almost absent; (c) mesosomal tergites are not lustrous but without granules, (d) sternite V bears two pairs of dentated carinae.

Material. 1♀ holotype: China: Tibet, Mêdog district (29°02’N, 95°03’E), Beibeng town , 22 August 2003, Feng Zhang leg. ( MHBU) . Paratypes: 2 ♀, Tibet, Bomi district (29°08’N, 95°07’E), 14 August 2002, Ming-Sheng Zhu leg. (one in MHBU and one in MNHN) ; 1 ♀, Tibet, Mêdog district , 108K-8K, 17 August 2003, Feng Zhang leg. ( MHBU) .

Etymology: The specific name refers to the spots on tergites.

Description (based on male holotype):

Coloration: Basically dark brown. Carapace is reddish-brown. Tergites are reddish-brown and darker than carapace, with a yellow stripe. Metasoma: all segments are dark brown, with some dark pigment on carinae. Telson is brown; aculeus is yellow at the base and black at the extremity. Chelicerae are yellowish with variegated brown spots; the fingers have darker denticles. Pedipalps: femur is brown; patella and chela are reddish-brown. Legs are sandy beige on proximal segments and yellowish on distal segments. Venter and sternites are pale brown. Sternite VII is darker than the others.

Morphology: Carapace is carinated, with densely coarse granules; lateral furrow is not prominent but posterior lateral furrow is more deep and distinct; median furrows are shallow at median eye level but deeper in the middle and posterior portion and bifurcated backwards. Lateral carinae are well developed; they are granular up to the lateral ocular tubercles. There is a pair of lateral eyes. A pair of small median eyes is same size as lateral eyes, and are located anterior to the center of the carapace. Tergites are coarsely granular. Each of tergites I-VI bears a pair of obsolete granular carinae on posterior margin. Tergite VII has two pairs of granular carinae developed only on posterior portion. Sternum is pentagonal and slightly longer than wide. Pectinal tooth count 5-5. Sternites are smooth; segment VII has two pairs of dentated carinae. Metasoma is about three times as long as carapace. Segment I is always wider than long; segments I to V have 10-10-10-8-7 carinae; segment V bears a ventromedian carina posteriorly bifurcated, all carinae are dentated. Vesicle is smooth. Chelicerae are small with elongated fingers; basal segment bears retiform dark brown pigmentation and smooth on ventral surface; thickly covered with numerous short, silky hairs, extending on ventral and dorsal portions of both fingers; the fingers are long and slender; their dentition characteristic for family and genus, but ventral inner edge of movable finger is provided with six minute teeth and immovable finger finely serrated.

Pedipalps: femur with dorsal internal and dorsal external carinae, which are minutely granular; ventral internal and ventral external carinae are smooth. Patella with dorsal and external carinae, which are granular; ventral carinae are smooth. Chela is rather narrow, with dorsal marginal, external secondary, and ventral internal carinae, which are moderately granular; ventral median carina is strong; tegument is granulated dorsally and punctated ventrally. Fingers are almost as long as manus and not flexed. Trichobothriotaxy of type B; orthobothriotaxic (Vachon, 1974); femur bears nine trichobothria, patella with 14, and chela with 14. Femur, patella, and tibia of leg all have yellow stripes. The legs are without tibial spur. Tarsus is provided with a pair of pedal spurs below with a row of long paired bristles. A single median row of short spinules is situated between the two rows of lateral setae on the ventral surface of leg tarsus.

Measurements (in mm) (female holotype). Total length, 48.93. Carapace: length, 7.01; anterior width, 2.68; posterior width, 7.01. Metasomal segment I: length, 2.68; width, 3.83. Metasomal segment V: length, 6.76; width, 2.30; depth, 2.30. Vesicle: width, 2.55; depth, 2.30. Pedipalp: femur length, 5.10, width, 2.42; patella length, 5.23, width, 2.55; chela length, 6.38, width, 4.21, depth, 4.08; movable finger length, 6.12.

Figures

Figure 109: Chaerilus tessellatus sp. n., female holotype, habitus. Total length 48.93 mm.

Figures 110–117: Chaerilus tessellatus sp. n., female holotype. 110–112. Chela, dorsoexternal, ventral and internal aspects. 113–115. Patella, dorsal, external and internal aspects. 116–117. Femur, dorsal and external aspects. Scales = 1 mm.

Figures 118–125: Chaerilus tessellatus sp. n., female holotype. 118. Carapace, dorsal aspect. 119–120. Chelicera, ventral and dorsal aspects. 1121–122. Metasomal segment V and telson, ventral and lateral aspects. 123. Lateral ocular region, in detail, dorsal aspect. 124. Sternum, genital operculum and pectines. 125. Dentate margin of the pedipalp chela movable finger. Scales = 1 mm.