Geophilus frenum Meinert, 1870: 74 (original description). Simophilus frenum: Silvestri, 1896: 154 (redescription). Attems, 1929a: 196 (redescription and in key).

Type locality: ‘ Bona’ = Annaba (Algeria).

Type material: Twenty-four syntypes, of which eight are males and 16 are females, up to 48-mm long; all are held in the Zoological Museum, University of Copenhagen, without catalogue number (H. Enghoff, pers. comm.).

Diagnosis: A Stenotaenia species of large body size (total length almost reaching 5 cm); c. 75–93 legbearing segments; labrum without or with one or two tubercles; first maxillae with distinct lappets on both the coxosternum and the telopodites; chitin lines of the forcipular coxosternum reaching the anterior condyles; anterior margin of the forcipular coxosternum almost straight; forcipular intermediate articles distinct; sternal pore areas in the anterior part of the trunk oval, slightly longer than wide, and placed on the posterior half of each sternum; each coxopleuron with one anterior and one posterior pouch with pores (see also Table 3).

Taxonomic history: After the original description by Meinert (1870), further specimens from a few other localities were identified by Silvestri (1896), who also redescribed the species and erected the new genus Simophilus for it. However, the true affinities of S. frenum were not recognized to date.

Assignment to Stenotaenia: It is assigned confidently to Stenotaenia (comb. nov.) based on the original description (Table 2), on Silvestri’s (1896) redescription, as well as on our direct study of other specimens that are obviously representative of this species (Figs 3, 4). It is noted here that the original description of the coxal pores was imprecise, as Meinert (1870) dubiously recognized only two large pores on each coxopleuron; later, Silvestri (1896) demonstrated that Meinert had misinterpreted two pouches with many glands each as two simple pores. Furthermore, indirect support to the placement of this species in Stenotaenia comes from the fact that Attems (1929b), in describing Simophilus albanensis, recognized that his new species, synonymized here under S. antecribellata (see above), was close to Meinert’s G. frenum.

Validity: It is treated here confidently as a distinct species, as published accounts and direct examination of representative specimens revealed some distinguishing traits (Table 3), as well as a disjunct distribution in respect to all other species of Stenotaenia.

Distribution: As far as is known, it is limited to the Eastern part of the Atlas chain (Fig. 3). In particular, it is known from nine localities, five of which are published here as new (see Appendix).