Chaerilus andamanensis, Lourenço & Duhem & Leguin, 2011

Lourenço, Wilson R., Duhem, Bernard & Leguin, Elise-Anne, 2011, The genus Chaerilus Simon, 1877 (Scorpiones, Chaerilidae) in the Indian Ocean Islands and description of a new species, Euscorpius 110 (110), pp. 1-8 : 3-7

Chaerilus andamanensis sp. n.

Figures 1 − 2 , 5 − 20

Diagnosis

Species of small size in relation to that of the other species in the genus, 24 mm in total length. General coloration yellowish, marked intensely with variegated brownish spots. Carapace moderately narrowed toward the anterior edge; acarinate and almost smooth; anterior margin almost straight with a minute concavity; furrows shallow. Metasomal carinae moderately marked; ventral carinae absent or obsolete on segments I and II, weakly marked on segments III and IV; latero-ventral and ventral carinae on segment V composed of spinoid granules. Telson with an elongated pear-like shape; aculeus very weakly curved. Dentate margins of fixed and movable fingers with 13-14 rows of granules. Pectinal tooth count 8- 8 in male. Genital operculum plates have a sub-oval shape. Trichobothriotaxy of type B, orthobothriotaxic. Hemispermatophore unknown .

Relationships

Chaerilus andamanensis sp. n., shows morphological similarities with Chaerilus variegatus Simon, 1877 and Chaerilus borneensis Simon, 1880 both described from the nearby Indonesian Islands of Java and Borneo. The new species can, however, be readily distinguished by the following combination of characters: (i) a pale coloration with variegated pigmentation, (ii) pectines with 8-8 teeth; a value rarely observed in the Indonesian species, (iii) Pedipalp chela fingers with 13-14 rows of granulations, (iv) movable finger of chela pedipalp without a basal lobe, (v) chela hand weakly enlarged.

Etymology. The specific name refers to the Islands of Andaman where the new species was collected.

Material. Indian , Andaman Islands, Little Andaman, VIII/1966 (collected by local people; Sreenivasa-Reddy leg.). Male holotype. Deposited in the Muséum national d’Histoire naturelle, Paris (MNHN-RS-8848) .

Description

Coloration: Basically yellowish to reddish-yellow, intensely marked with variegated brownish. Carapace reddish-yellow, with dark spots anteriorly. Tergites yellowish with diffused variegated spots. Metasomal segments yellowish with variegated spots. Telson yellowish with variegated spots; tip of aculeus reddish. Chelicerae yellowish with variegated spots; fingers and teeth dark reddish. Pedipalps reddish-yellow; femur and patella more intensely spotted than chela; dentate margins of fingers dark reddish. Legs yellowish with diffused brownish spots. Venter and sternites yellowish; pectines pale yellow.

Morphology: Carapace moderately narrowed anteriorly; anterior margin almost straight, with a minute concavity; acarinate and almost smooth, with some minute granulations laterally; furrows shallow. Two pairs of lateral eyes, and one pair of moderate median eyes, about 1.5 times the size of lateral eyes; median eyes anterior to the centre of the carapace. Tergites smooth; carinae obsolete. Sternum pentagonal, longer than wide; genital operculum plates with sub-oval shape; genital papillae not observable. Pectinal tooth count 8- 8 in male holotype. Sternites smooth with spiracles small and oval-shaped; carinae absent from VII. Metasomal segments I to III wider than long; segments IV and V longer than wide. All the carinae moderately granular; ventral carinae absent or obsolete on segments I and II, weakly marked on segments III and IV; latero-ventral and ventral carinae on segment V composed of spinoid granules. Vesicle elongated with a pear-like shape, smooth; aculeus short and weakly curved. Pedipalps not elongated; femur with five carinae; internal with a few spinoid granules. Patella with seven vestigial carinae. Chela weakly enlarged and with eight carinae, weakly to moderately granular. Tegument almost smooth. Fixed and movable fingers shorter than manus, with 13-14 rows of granulations on the dentate margins; movable finger of chela pedipalp without a basal lobe. Chelicerae characteristic of the family Chaerilidae (Vachon, 1963) ; with four va denticles on the fixed finger. Trichobothriotaxy of type B; orthobothriotaxic (Vachon, 1974); femur with 9 trichobothria, patella with 14, and chela with 14. Legs with pedal spurs strongly developed. Tarsi with two rows of spiniform setae and a medial line of 6, 7, 7, 8 small spinules on legs I to IV. Hemispermatophore unknown .

Morphometric values (in mm) of the male holotype. Total length (including telson), 24.4 (including telson). Carapace: length, 4.0; anterior width, 2.0; posterior width, 3.8. Mesosoma length, 6.8. Metasomal segments. I: length, 1.3; width, 1.9; II: length, 1.6; width, 1.8; III: length, 1.7; width, 1.8; IV: length, 1.9; width, 1.7; V: length, 3.2; width, 1.6; depth, 1.3. Telson length, 3.9. Vesicle: width, 1.7; depth, 1.4. Pedipalp: femur length, 2.9, width, 1.4; patella length, 3.1, width, 1.5; chela length, 6.3, width, 2.0, depth, 2.5; movable finger length, 3.3 .

Figures

Figures 1−4: 1−2. Chaerilus andamanensis sp. n., male holotype. Dorsal and ventral aspects. 3−4. Chaerilus borneensis, male from north of Borneo. Dorsal and ventral aspects (scale bars = 1 cm).

Figures 5−10: Chaerilus andamanensis sp. n., male holotype. 5. Chelicera. 6. Carapace. 7. Metasomal segment V and telson, lateral aspect. 8. Cutting edge of movable finger with rows of granules and absence of a basal lobe. 9−10. Idem for Chaerilus borneensis, male holotype, without a basal lobe and, for Chaerilus variegatus, male from Java, with a basal lobe.

Figures 11−12: Male sternum, genital operculum and pectines. 11. Chaerilus andamanensis sp. n., male holotype. 12. Chaerilus borneensis, male from North of Borneo.

Figures 13−20: Chaerilus andamanensis sp. n., male holotype. Trichobothrial pattern. 13−15. Chela, dorso-external, ventral and internal aspects. 16−18. Patella, dorsal, external and ventral aspects. 19−20. Femur, dorsal and external aspects.