Compsobuthus mahazat, Ythier & Lourenço, 2023

Ythier, Eric & Lourenço, Wilson R., 2023, Two new scorpionspecies from Central SaudiArabia (Scorpiones: Buthidae), Faunitaxys (London, England) 11 (8), pp. 1-8 : 2-3

Compsobuthus mahazat sp. n.

( Fig. 1-7 , Tab. I)

ZooBank:http://zoobank.org/ 4447027F-0ACE-41C4-BEE4-717297D6AB7C

Holotype, ♂, Saudi Arabia, Central region , Mahazat as-Sayd Reserve (22.26931°N 41.83913°E), 250 km E of Taif, on the road between Djeddah and Ryadh, between 900-1100 m a.s.l., III-V/1990 (C. Launay / National Wildlife Research Center), MNHN.

Etymology. – The specific name is placed in apposition to the generic name and refers to the Reserve of Mahazat as-Sayd, Saudi Arabia, where the new species occurs.

Diagnosis. – Scorpion of medium size when compared to other known species of the genus in Saudi Arabia, reaching a total length of 24 mm. General coloration yellowish to pale yellow without any spots; eyes surrounded by black pigment. Carinae on carapace and tergites moderately to strongly developed; granulations moderately marked. Sternites smooth, without setae. Pectines with 19-19 teeth in male, female unknown. Metasomal segments I-V with 10-10-10-10-5 carinae; intermediate carinae complete on I-III, incomplete on IV. Telson weakly granular with ventral and latero-ventral carinae; aculeus shorter than vesicle; subaculear tubercle vestigial. Trichobothrial pattern orthobothriotaxic, type A-β (beta). Femur and patella with moderately to strongly marked carinae. Chela slender with fingers moderately elongated, straight (without proximal gap between pedipalp chela fingers when closed). Dentate margins on movable and fixed fingers composed of 10-11 almost linear rows of granules; inner accessory granules reduced; outer accessory granules absent (‘ acutecarinatus’ group).

Description (based on male holotype, measurements in Table I).

Coloration. –Generally yellowish to pale yellow without any spots. Prosoma: carapace yellowish; eyes surrounded by black pigment. Mesosoma yellowish. Metasomal segments yellowish; vesicle yellowish; aculeus yellowish at the base and reddish at the tip. Venter and legs pale yellow. Chelicerae pale yellow, with teeth pale red. Pedipalps pale yellow overall; rows of granules on the dentate margins of the fingers pale red.

Morphology. – Prosoma: anterior margin of carapace weakly emarginate. Carapace carinae moderately developed; anterior median, central median, posterior median and central lateral moderately marked; posterior median carinae terminating distally in a small spinoid process that extends beyond the posterior margin of the carapace. Intercarinal spaces weakly granular; almost smoothcentrally. Median ocular tubercle anterior tothe centre of the carapace; median eyes separated by more than one ocular diameter. Three pairsof lateral eyes. Mesosoma: tergites I-VI tricarinate. Lateral carinae on I-VI strongly marked; each carina terminating distally with a spinoid process that extends stronglybeyond theposterior margin of tergite. Mediancarinae on I weak;onII- VI moderate to strong, crenulate; terminating distally on each segment with a spinoid process that extends slightly beyond the posterior margin of the tergite. Tergite VII pentacarinate, with lateral pairs of carinae moderate to strong; median carinae present on proximal one-half, moderate. Intercarinal spaces moderately granular. Sternites: lateral carinae absent from sternites III-IV, vestigial on V, weak on VI, moderate, finely crenulate on VII. Submedian carinae absent from sternites III-V, vestigial on VI, moderate, finely crenulate on VII. Intercarinal spaces smooth, without setae. Pectines: pectinal tooth count 19-19. Metasoma: segments I-IV with ten carinae, crenulate; intermediate carinae complete on I-III, incomplete on IV. Segment V with five carinae; ventromedian carinae moderate to weak. Dorsal furrows of all segments weakly developed; intercarinal spaces weakly granular. Telson weakly granular with ventral and latero-ventral carinae; aculeus shorter than the vesicle; subaculear tubercle vestigial, rhomboid. Chelicerae with two denticles at the base of the movable finger, partially fused (Vachon, 1963). Pedipalps: trichobothrial pattern orthobothriotaxic, type A (Vachon, 1974); dorsal trichobothria of femur in β (beta) configuration (Vachon, 1975). Femur pentacarinate; all carinae moderatelycrenulate. Patella witheightcarinae;all carinae moderately marked; dorsointernal carinae with one spinoid granule. Chela slender, with fingers moderately elongated, straight (without proximal gap between pedipalp chela fingers when closed); all carinae moderately marked. Dentate margins on movable and fixed fingers composed of 10-11 almost linear rows of granules; inner accessory granulesreduced; outer accessorygranules absent.Legs: ventral aspect of tarsi with two rows of setae. Tibial spurs present on legs III and IV, moderate. Pedal spurs present, moderate on all legs.

Relationships. – Compsobuthus mahazat sp. n. can be distinguished from the other species of Compsobuthus occurring in Saudi Arabia, notably by the following characters:

(i) dentate margins on pedipalp chela movable and fixed fingers composed of 10-11 rows of granules (7-9 in C. arabicus and 9-10 in C. khaybari and C. setosus ),

(ii) outer accessory granules absent on dentate margins of chela fingers (present in C. khaybari , C. longipalpis and C. manzonii ),

(iii) pectines with 19-19 teeth in male (13-16 in male C. arabicus ),

(iv) chela fingers straight in male, without proximal gap between pedipalp chela fingers when closed (fingers scalloped in males C. khaybari , C. manzonii and C. pallidus ),

(v) sternite VII and ventral surface of metasoma without setae (numerous setae in C. khaybari and C. setosus ).

Figures

Fig. 1-2. Compsobuthus mahazat sp. n., ♂ holotype, habitus. 1. Dorsal aspect. 2. Ventral aspect.

Fig. 3-7. Compsobuthus mahazat sp. n., ♂ holotype, trichobothrial pattern.