New Insights on Genetic and Morphological Divergence Among a Buthus Species Complex From Tunisia With the Identification of a New Species.

The taxonomy of the scorpion genus Buthus is complex due to the considerable increase in newly reported species, their high degree of similarity, and consequently, the great difficulty in their morphological differentiation. Tunisian species are not exempt from this issue, with several references highlighting the need for taxonomic revisions. This study integrates DNA sequence data and morphological assessments to investigate the diversity present in Tunisia and to provide morphological details that facilitate species identification. The results show that most Tunisian specimens are distributed within two clades. One clade comprises four subclades corresponding to B. tunetanus Herbst, 1800, B. paris C. L. Koch, 1839, B. chambiensis Kovařík 2006 and a southern group corresponding probably to B. lourencoi Rossi, Tropea & Yağmur, 2013. The second clade represents a new species described in this study as B. saidnouirai Hajri, Bahri & Harris, sp. nov. No evidence of B. dunlopi Kovařík 2006 have been recorded in the studied samples. Distances between all five species exceed the minimum divergence thresholds for Buthus species. The greatest distance was observed between B. saidnouirai. sp. nov. and the southern group, while the smallest distance was between B. tunetanus and B. paris. Although the genetic differences revealed considerable divergence of the new group from the four remaining species, the morphological assessment did not identify the same pattern. These five species demonstrate a morphological shape gradient in which B. paris and the southern group represent the two extremes, with B. paris being the most ornamented and the latter the least. The new species presents an intermediate morphology. The geographic distributions of the five reported species are discussed in this work according to the topography and orography of the region. Additional lineages known from Algeria may also enter the western fringes of Tunisia.