Guyanochactas touroulti, Lourenço, 2018

Lourenço, Wilson R., 2018, The scorpions from the Mitaraka Massif in French Guiana (Scorpiones: Buthidae, Chactidae), Zoosystema 40 (14), pp. 367-374 : 370-371

Guyanochactas touroulti n. sp.

( Figs 3-5 )

urn:lsid:zoobank.org:act:FA6C238C-9415-4A9E-A47D-02FA965451C9

MATERIAL EXAMINED. — French Guiana. ♀ holotype, Mitaraka, ‘ La Planète Revisitée – MNHN /PNI Guyane 2015 ( APA 973-1 )’, MI15 - 0471. Layon C, parcel 9, hand collection, in litter during the night, 2.238334, –54.449117, 23.II-11.III.2015 ( V. Vedel & J. Murienne), MNHN .

ETYMOLOGY. — Name honors Julien Touroult (MNHN) one of the organizers of the Field Expedition to the Mitaraka Massif.

DIAGNOSIS. — Scorpion of moderate size, as the other species of the genus, with 36.4 mm in total length. Coloration dark brown to almost blackish. Carapace slightly emarginated. Body and appendages weakly granulated, with minute punctations. Ventral internal carina of pedipalp femur with spinoid granules; internal face of pedipalp chela granulated and with 2-3 spinoid granules. Pectines with 9-10 teeth in female holotype. Dentate margin of chela fingers with six rows of granules. Metasomal segments I and II wider than long; III as long as wide. Spiracles oval. Tarsi with two rows of spinoid setae. Trichobothrial pattern of type C neobothriotaxic ‘majorante’. Guyanochactas touroulti n. sp. can be distinguished from other species in the genus Guyanochactas and in particular from Guyanochactas gonzalezspongai ( Lourenço, 1983) and Guyanochactas flavus Lourenço & Ythier, 2011 , both also distributed in French Guiana, by the following features: 1) overall much darker coloration, almost totally blackish; 2) overall size smaller with only metasomal segments I-II wider than long; 3) smaller number of pectinal teeth; and 4) chela fingers with six rows of granules.

DESCRIPTION BASED ON FEMALE HOLOTYPE

Coloration

Basically dark brown to blackish. Prosoma: carapace dark brown to blackish with some slightly reddish zones on furrows; eyes blackish.Tergites dark brown to blackish, with confluent zones slightly reddish. Metasomal segments dark brown with blackish zones over carinae; telson reddish, darker ventrally; aculeus reddish at the base and blackish at the tip. Chelicerae yellowish with blackish variegated pigmentation; fingers and teeth blackish.Pedipalps dark brown to blackish; femur darker than patella and chela. Legs reddish-brown with darker spots. Venter: sternites, coxapophysis and sternum reddish-brown; pectines and genital operculum yellow to pale yellow.

Morphology

Carapace slightly emarginated, with minute granulations and punctations; furrows shallow. Median eyes largely anterior to the centre of the carapace, separated by a little more than one ocular diameter; two pairs of lateral eyes, moderate in size. Sternum pentagonal, wider than long.Tergites acarinate, with only minute granulations and punctations. Pectinal tooth count 9-10 for holotype; fulcra vestigial. Sternites smooth and punctuated; spiracles oval in shape. Metasomal segments I to II wider than long; metasomal tegument with moderately marked granulations and a few punctuations; dorsal carinae strongly marked on all segments with spinoid granules; other carinae strongly marked on segments III-V, weaker on segments I-II; segment V with spinoid granulations ventrally.Telson elongated and weakly globular with strongly marked granulation ventrally; aculeous moderately elongated. Pedipalps: femur with dorsal internal, dorsal external and ventral internal carinae strongly marked; ventral internal carina with spinoid granules; ventral external carina weakly to moderately marked; all faces with minute granulations. Patella with minute granulations and punctations; dorsal internal, ventral internal, ventral external and external carinae weakly marked; other carinae vestigial. Chela with weakly marked carinae and a few granulations on internal aspect. Dentate margins on movable and fixed fingers with six rows of granules, separated by stronger accessory granules. Chelicerae moderately elongated with a dentition typical of the family Chactidae ( Vachon 1963) , and with dense setation ventrally and internally. Trichobothriotaxy of type C; neobothriotaxic ‘majorante’ ( Vachon 1974). Tarsi with two rows of spinoid setae.

Morphometric values (in mm) of female holotype

Total length including telson, 36.4. Carapace: length, 5.1; anterior width, 3.2; posterior width, 5.2. Mesosoma length, 11.9. Metasomal segments. I: length, 2.0; width, 3.0; II: length, 2.3; width, 2.6; III: length, 2.4; width, 2.4; IV: length, 2.9; width, 2.3; V: length, 4.9; width, 2.1; depth, 1.7. Telson length, 4.9; width, 1.6; depth, 1.3. Pedipalp: femur length, 3.8, width, 1.7; patella length, 4.4, width, 1.8; chela length, 8.5, width, 2.8, depth, 2.9; movable finger length, 4.2.

Figures

FIG. 3. — A, B, Guyanochactas touroulti n. sp., ♀ holotype habitus, dorsal (A) and ventral (B) views. Scale bar: 1 cm.

FIG. 4. — Guyanochactas touroulti n. sp., ♀ holotype: A, chelicera,dorsal view; B, sternites IV-V showing spiracles; C, tarsi of leg IV showing the series of spines; D, metasomal segment V and telson, lateral view. Scale bars: 1 mm.

FIG. 5. — Guyanochactas touroulti n. sp., ♀ holotype, trichobothrial pattern: A, chela, dorso-external view; B, femur dorsal view; C-E, patella, dorsal, external and ventral views. Scale bar: 2 mm.