Isometrus maculatus (DeGeer, 1778)

Ythier, Eric, 2018, A synopsis of the scorpion fauna of French Guiana, with description of four new species, ZooKeys 764, pp. 27-90: 32-34

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Isometrus maculatus (DeGeer, 1778)


Isometrus maculatus (DeGeer, 1778)  Fig. 8


DeGeer 1778, Lourenço 1983, Fet et al. 2000.


Cayenne, four males and three females, MNHN-RS-0899, M. Richard coll. Cayenne, one male and two females, MNHN-RS-3315, E. Abonnenc coll. Charvein-Maroni river, one male, MNHN-RS-3323, F. Geay coll., 1903. Coswine river, under rotten wood, one female, MNHN-RS-8299, J. Fretey coll., 16/V/1977. Morne-Cépéron, one male, MNHN RS3324, F. Geay coll., 1902. St. Jean du Maroni, two males, three females and two immatures, MNHN-RS3322, R. Benoist coll., 1914. St. Jean du Maroni, one male, MNHNRS7286, F. Geay coll., 1903. Disputed area between Oyapock and Amapa, one female, MNHN-RS0925. D. Villecourt coll., 1899. Disputed area between Oyapock and Amapa, one male, MNHNRS0914, F. Geay coll., 1899. Disputed area between Oyapock and Amapa, five males, sic females and one immature, MNHNRS0893, Lafon coll., 1872.


Species of medium to large size when compared with the average size of the other species of the genus, ranging from 50.1 mm (female) to 61.2 mm (male) in total length. General coloration yellowish to pale yellow, symmetrically marbled with blackish brown spots in both adults and juveniles. Carapace yellow ish with blackish brown patterns; eyes surrounded by black pigment. Mesosoma yellowish with symmetrical blackish brown stripes. Venter yellowish; sternites III-VII with symmetrical brown spots. Metasomal segments pale yellow, with some diffuse, brownish spots. Vesicle pale yellow with basis of aculeus yellowish and tip of aculeus reddish brown. Chelicerae pale yellow with brownish variegated spots; base of fingers pale yellow, rest of fingers blackish brown, teeth reddish. Pedipalps pale yellow with brownish spots; chela fingers reddish brown; rows of granules on dentate margins of fingers dark reddish. Legs yellowish with diffuse spots. Carapace coarsely granular with a few smooth patches; anterior margin strongly emarginated, with an open V-shaped angle; carinae weakly developed. Tergites moderately granular; median carinae weak to moderate on I-VI, tergite VII with two lateral pairs of carinae moderate to strong. Pectinal tooth count ranging from 16-19 in male and 17-19 in female. Sternites smooth and shiny, VII with four granular carinae. Metasomal segments with 10-10-8-8-5 crenulate carinae; intercarinal spaces very weakly granular to smooth. Telson very weakly granular, almost smooth, with one vestigial ventral carina; subaculear tubercle marked and triangular, with two granules on the ventral surface. Pedipalp femur with all carinae crenulate; patella with seven crenulate carinae; chela with vestigial carinae; dentate margins of fixed and movable fingers with six linear rows of granules. Leg tibia with few setae, without spurs; basitarsus with some setae and two lateral pedal spurs; tarsus ventrally with two rows of short setae.