Acanthicini Bleeker, 1862

Armbruster, Jonathan W. & Lujan, Nathan K., 2024, New tribe-level classification of Hypostominae (Loricariidae) based on optimization of morphological states on DNA-based relationships, with descriptions of three new tribes and two new genera, Neotropical Ichthyology (e 240108) 22 (4) : -

Tribe Acanthicini Bleeker, 1862 -1863

Included genera.

Acanthicus Agassiz, 1829:2 (in Spix, Agassiz, 1829). Type-species: Acanthicus hystrix Spix & Agassiz, 1829 .

Leporacanthicus Isbrücker, Nijssen, 1989:544 . Type-species: Leporacanthicus galaxias Isbrücker & Nijssen, 1989 .

Megalancistrus Isbrücker, 1980:52 . Type-species: Chaetostoma gigas Boulenger, 1895 .

Pseudacanthicus Bleeker, 1862:2 . Type-species: Chaetostomus serratus Valenciennes, 1840 (in Cuvier, Valenciennes, 1840). Synonym: Stoniella Fowler, 1914.

Phylogenetic diagnosis. Anterohyal greatest width greater than half its length (1:1), loss of flap on quadrate extending below symplectic foramen (66:0), mesethmoid disk extending anterior to main body of mesethmoid (101:1), large fenestrae in compound pterotic (109:1, reversed in Leporacanthicus ), tip of transverse process of Weberian complex centrum not contacting compound pterotic (135:1, reversed in Leporacanthicus ), eight or more dorsal-fin rays (142:1), hypertrophied odontodes along snout margin (188>1), and keels of lateral plates well developed (198:1).

Comparative diagnosis. Acanthicini can be separated from all other Hypostominae except some Pterygoplichthys Gill, 1858 (particularly P. weberi ) by having lateral-plate keels made of long, stout odontodes, from all other Hypostominae except Colossimystax and Pterygoplichthys by having more than seven dorsal-fin rays, and from Pterygoplichthys with keels by having strongly evertible cheek odontodes (vs. weakly evertible), by having fewer odontodes dorsal and ventral to keel rows (vs. odontodes normally distributed). In addition, Acanthicus can be separated from Pterygoplichthys by lacking an adipose fin (vs. adipose fin present), Acanthicus and Megalancistrus can be separated from Pterygoplichthys by having compound pterotic extending beyond posteriormost insertion of pectoral fin (vs. maximally through ~3/4 of pectoral-fin base); and Leporacanthicus and Pseudacanthicus can be separated from Pterygoplichthys by having 10 or fewer teeth per jaw ramus (vs. more than 20).

Geographical distribution. Restricted to larger, main river channel habitats in cis-Andean drainages from the Paraná and São Francisco basins northward, including the Amazon and Orinoco basins and north-flowing Guiana Shield basins.