Hypostominae KNER 1853
Creators: name: Armbruster, Jonathan W.
Publisher: name: Zenodo
Year: 2004
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Siluriformes
Loricariidae

description: SUBFAMILY HYPOSTOMINAE KNER,1853  Synonyms:  
Ancistri Kner, 1853  
Hypostomiden Kner, 1853  
Lictores Kner, 1853  
Plecostomiformes Bleeker, 1862  
Chaetostomidi Fowler, 1958  
Includes:  
Ancistrini Kner, 1853  
 Corymbophanini new tribe   
Hypostomini Kner, 1853  
 Pterygoplichthini new tribe   
 Rhinelepini new tribe   
 Type genus: Hypostomus Lacépède, 1808.   
 Diagnosis: The Hypostominae is diagnosed by a unique characteristic: the lower lobe of the hypural plate longer than the upper (123: 1; Fig. 24B). Other characteristics considered synapomorphic for Hypostominae are: a long accessory process on the first ceratobranchial (7: 2; Fig. 9E; reversed in some groups), a small canal plate (83: 1), a V-shaped spinelet (148: 0), and a posteroventral ridge on the basipterygium (173: 1; Fig. 33C, E, F).   
 Description: With the inclusion of the Ancistrinae (and exclusion of some genera formerly within it) the Hypostominae becomes the largest of the loricariid subfamilies in number of species (366 currently valid). Size is incredibly variable within the subfamily, which includes small genera such as Lithoxus (50 mm) and the largest of all loricariids, Acanthicus (maximum size probably around 1 m). Hypostomines are typically bulkier than other loricariids and generally have thicker plates than neoplecostomines. The tribe and generic descriptions below provide more information on the diversity of forms.   
 Comparisons: The best character to distinguish the Hypostominae from most other loricariids is the development of the spinelet. In all the Hypostominae, the spinelet is large and V-shaped and clearly slides under the nuchal plate, whereas it is square or absent in most other loricariids and, when present, does not slide under the nuchal plate. Some hypoptopomatines have a triangular spinelet, but these species can be distinguished from the Hypostominae by a completely or nearly completely exposed pectoral girdle (vs. at most some odontodes supported by the coracoid strut), the adductor fossa of the pectoral girdle covered by bone (vs. wholly exposed), and by having the fenestrae of the pterotic-supracleithrum larger ventrally than dorsally (vs. all fenestrae of about equal size). Delturus also has a triangular spinelet but can be distinguished by the presence of an adipose fin with a postdorsal ridge (all hypostomines with a postdorsal ridge lack an adipose fin). The Chaetostoma group and some Ancistrus have the spinelet covered in skin; these species can be distinguished from the other loricariid subfamilies by the presence of evertible cheek plates with hypertrophied odontodes. The Hypostominae further differs from the Loricariinae by having a round, oval, or triangular cross-section of the caudal peduncle (vs. rectangular and depressed).
description: Published as part of Armbruster, Jonathan W., 2004, Phylogenetic relationships of the suckermouth armoured catfishes (Loricariidae) with emphasis on the Hypostominae and the Ancistrinae, pp. 1-80 in Zoological Journal of the Linnean Society 141 (1) on page 58, DOI: 10.1111/j.1096-3642.2004.00109.x, http://zenodo.org/record/5429286