Atlantor Borkenhagen & Freyhof 2023, new genus

Atlantor, new genus

Figs 1–2

Material examined. BMNH 1874.1.30.22-24, 3, syntypes, 96–155 mm SL; Morocco: Oued Tensift, [32°1′58″N, 9°20′39″W]; K. v. Fritsch & J. Rein, 1872.— BMNH 1901.7.26.2-3, 2, 125–146 mm SL; Morocco: Oued Oum er Rbia [33°19′40″N, 8°20′2″W]; E. Hartert.— MNHN 1912-94, 1, 120 mm SL; MNHN 1912-95, 1, 124 mm SL; MNHN 1912-96, 1, 92 mm SL; Morocco: Oued Oum er Rbia near Azemmour [33°17′22″N, 8°20′33″W], C. du Gast, 1912.— MNHN 1927-98, 1, 111 mm SL; Morocco: Oued Oum er Rbia near Khenifra [32°56′21″N, 5°40′7″W], A. Gruvel & R. Dollfus, 1927.— SMF 636, 1, 82 mm SL; SMF 952, 2, 49–83 mm SL; Morocco: Oued Ksob [31°28′59″N, W 9°46′3″W], K. v. Fritsch & J. Rein, 1872.

Diagnosis. Atlantor is distinguished from Carasobarbus by having 5½ branched anal-fin rays (vs. 6½), and modally 8½ branched dorsal-fin ray (vs. 9½–10½), and from Mesopotamichthys and Caecocypris by having two pairs of long barbels (vs. no barbels). There is no consistent morphological character that clearly distinguishes Atlantor from all species of Arabibarbus and Labeobarbus, and the new genus can only be distinguished from Arabibarbus and Labeobarbus by its distinct phylogenetic position and genetic distance (p-distance in cytochrome b of 5.3% and 6.7% respectively; Kai Borkenhagen, unpublished). Atlantor differs from Pterocapoeta by having two pairs of long barbels (vs. one pair of minute maxillary barbels hidden in a skin fold), dorsal fin with 8½–9½ branched rays (vs. 10½–11½), 25–32 total lateral line scales (vs. 43–46), well developed, fleshy lips and a small median lobe on the lower lip (vs. lower lip with cornified sheath), mouth arched (vs. straight). Current knowledge indicates that all Western Asian, and African Torinae are evolutionarily hexaploid, and as Atlantor belongs to this phylogenetic group of species, it is assumed, that they are also hexaploid. As a consequence, Atlantor is distinguished from the Indomalayan genera Hypselobarbus, Lepidopygopsis, Naziritor, Neolissochilus, Osteochilichthys, and from Tor by being evolutionarily hexaploid (vs. tetraploid (2n≈100) (Yang et al. 2015).

Type species. Barbus reinii Günther, 1874: 231

Included species. Barbus reinii Günther, 1874:231

Etymology. The name is derived from the Atlas Mountains in Morocco and Tor, the generic name of the tribe that includes Atlantor (neutral).

Distribution and conservation status. The type locality of A. reinii is the Tennsift River in Morocco (Günther 1874). Records from the Oum er Rbia (Günther 1902, Pellegrin 1921) are confirmed by vouchers (MNHN 1912-94– 96, MNHN 1927-98). In recent years, the species was only found in the Ksob River, a tributary to Oued Igrounzar, by Machordom & Doadrio (2001) (I. Doadrio, pers. communication, 2019). Atlantor reinii has not been found since 2001, despite a number of attempts to confirm its continued existence. Freyhof & Ford (2022) treat A. reinii as extinct.

Remarks. There are only two cytochrome b sequences available, which were published by Machordom & Doadrio (2001) and Durand et al. (2002), and later included in phylogenetic studies by Tsigenopoulos et al. (2010), Berrebi et al. (2014), Borkenhagen (2014), Yang et al. (2015). All these studies show Atlantor as a distinct phylogenetic lineage from related genera such as Arabibarbus, Carasobarbus, Labeobarbus, Mesopotamichthys, and Ptercapoeta. We have not reproduced the phylogenetic trees here, as they are available open-access from their original sources, which indicate the unique phylogenetic position of Atlantor.

Comparative material. See Borkenhagen & Krupp (2013) and Borkenhagen (2014) for materials of additional species and genera examined.