T. N. Gill, 1858
Spix & Agassiz, 1829
Pterygoplichthys is derived from the Greek πτέρυγ- (pteryg-), meaning "wing", (hoplon) - weapon and ἰχθύς (ichthys) meaning "fish".
Pterygoplichthys has undergone much shifting in the past decades. Previously Liposarcus, Glyptoperichthys and Pterygoplichthys had been named as separate genera. Since then, these genera were recognized as synonyms of Pterygoplichthys by Armbruster, as the few differences between the genera were not deemed great enough to validate Glyptoperichthys and Liposarcus, and that recognizing these separate genera would leave neither Pterygoplichthys nor Glyptoperichthys as monophyletic.
There are currently 16 recognized species in this genus: 
- Pterygoplichthys ambrosettii (Holmberg, 1893)
- Pterygoplichthys anisitsi C. H. Eigenmann & C. H. Kennedy, 1903 (Snow pleco)
- Pterygoplichthys disjunctivus (C. Weber, 1991) (Vermiculated sailfin catfish)
- Pterygoplichthys etentaculatus (Spix & Agassiz, 1829)
- Pterygoplichthys gibbiceps (Kner, 1854) (Leopard pleco)
- Pterygoplichthys joselimaianus (C. Weber, 1991)
- Pterygoplichthys lituratus (Kner, 1854)
- Pterygoplichthys multiradiatus Hancock, 1828 (Orinoco sailfin catfish)
- Pterygoplichthys pardalis (Castelnau, 1855) (Amazon sailfin catfish)
- Pterygoplichthys parnaibae (C. Weber, 1991)
- Pterygoplichthys punctatus (Kner, 1854) (Corroncho)
- Pterygoplichthys scrophus (Cope, 1874)
- Pterygoplichthys undecimalis (Steindachner, 1878)
- Pterygoplichthys weberi Armbruster & Page, 2006
- Pterygoplichthys xinguensis (C. Weber, 1991)
- Pterygoplichthys zuliaensis C. Weber, 1991
Appearance and anatomy
Pterygoplichthys can be differentiated from most other loricariids due to their large dorsal fins with 9 or more (usually 10) dorsal fin rays, which gives them their common name "sailfin catfish". These fish have rows of armour plating covering the body; the abdomen is almost completely covered in small plates. Other characteristics of members of this genus include an underslung suckermouth, evertable cheek plates, adipose fin present, and an enlarged stomach connected to the dorsal abdominal wall by a connective tissue sheet. P. anisitsi, P. disjunctivus, P. multiradiatus, and P. pardalis lack cheek odontodes, but still possess the evertible cheek plates; this was previously used as a trait to determine these fish as part of the genus Liposarcus. Species of the P. gibbiceps group (species formerly classified in the genus Glyptoperichthys) are easily recognized by a large crest above the back of their skull.
Color pattern is generally dark brown with either darker spots or lighter spots or vermiculations. The adult size of a member of Pterygoplichthys can range from about 50–70 cm.
The stomach of Pterygoplichthys is greatly expanded with the posterior portion forming a long, thin sac that is highly vascularized.
Distribution and habitat
Pterygoplichthys' habitat is most common in sluggish streams, floodplain lakes, and marshes. They are known from the Orinoco, Amazon, Magdalena, Maracaibo, Paraná, Parnaíba and São Francisco systems.
These fish have been introduced into many locations. Several species of Pterygoplichthys have been established in the United States in Florida, Hawaii, Nevada, and Texas. Established species include P. multiradiatus in Florida and Hawaii, P. disjunctivus in Florida, and P. anisitsi in Texas. Sailfin catfish are one of the more successful established exotic fish in Florida in terms of their range extension and abundance, yet their presence has not had any measurable effect on native fishes, although they have contributed significantly to the carrying capacity of some fish communities. Moreover, none of the 30 professional water managers, engineers, lake management, and shoreline stabilization company owners contacted in 2004 by a particular study considered erosion caused by the burrowing activity of loricariid catfishes a major problem, except in some man-made lakes in the southeastern part of the state.
In Mexico, P. multiradiatus is established in Campeche, Chiapas, and other localities in central and western Mexico, while P. pardalis has been found in southeastern Mexico. In the Philippines, where these fish are known as janitor fish, P. disjunctivus and P. pardalis have been found, these fish are considered a threat to the freshwater fish population; they are found in the Marikina River and Laguna de Bay. P. multiradiatus has also been established in Puerto Rico and Taiwan.
In the aquarium
P. gibbiceps has been bred commercially in fish farms in Florida and Malaysia for the aquarium trade. P. multiradiatus and P. pardalis are both known as common plecos and are widely sold as algae eaters. However, most of them grow too large to be housed in an average home aquarium. In fact, in the wild, the Common Pleco can well exceed 2 feet in length, and, as well as growing large, they also produce a lot of waste that can pollute the water.
- Pterygoplichthys is an exact anagram of Glyptoperichthys.
- Froese, Rainer, and Daniel Pauly, eds. (2011). Species of Pterygoplichthys in FishBase. December 2011 version.
- C. Weber (1991). "Nouveaux taxa dans Pterygoplichthys sensu lato (Pisces, Siluriformes, Loricariidae)". Revue Suisse de Zoologie.
- C. Weber (1992). "Révision du genre Pterygoplichthys sensu lato". Revue Francaise díAquariologie Herpétologie.
- "Jonathan W. Armbruster" (2004). "Phylogenetic relationships of the suckermouth armoured catfishes (Loricariidae) with emphasis on the Hypostominae and the Ancistrinae (abstract)". Zoological Journal of the Linnean Society 141: 1. doi:10.1111/j.1096-3642.2004.00109.x.
- Armbruster, Jonathan W. "Pterygoplichthys (Gill, 1858)".
- Froese, Rainer, and Daniel Pauly, eds. (2011). Species of XXXXX in FishBase. December 2011 version.
- Armbruster, Jonathan W.; Page, Lawrence M. (2006). "Redescription of Pterygoplichthys punctatus and description of a new species of Pterygoplichthys (Siluriformes: Loricariidae)" (PDF). Neotropical Ichthyology 4 (4): 401–409. doi:10.1590/S1679-62252006000400003.
- "Modifications of the Digestive Tract for Holding Air in Loricariid and Scoloplacid Catfishes" (PDF). Copeia (3): 663–675. 1998. Retrieved 2009-06-25.
- Froese, Rainer and Pauly, Daniel, eds. (2013). "Pterygoplichthys parnaibae" in FishBase. May 2013 version.
- Chavez, Joel M.; de la Paz, Reynaldo M.; Manohar, Surya Krishna; Pagulayan, Roberto C.; Carandang Vi, Jose R. (2006). "New Philippine record of South American sailfin catfishes (Pisces: Loricariidae)" (PDF). Zootaxa 1109: 57–68. Retrieved 2009-06-25.
- Nico, Leo G.; Martin, R. Trent (March 2001). "The South American Suckermouth Armored Catfish, Pterygoplichthys anisitsi (Pisces: Loricaridae), in Texas, with Comments on Foreign Fish Introductions in the American Southwest". The Southwestern Naturalist 46 (1): 98–104. doi:10.2307/3672381. JSTOR 3672381.
- Gestring, Kelly; Shafland, Paul; Stanford, Murray (2006). "The status of loricariid catfishes in Florida with emphasis on sailfin catfish (Pterygoplichthys multiradiatus) (abstract)". Merida, Mexico. Retrieved 2007-06-04.
- Wakida-Kusunokia, Armando T.; Ruiz-Carusb, Ramon; Amador-del-Angelc, Enrique (March 2007). "Amazon Sailfin Catfish, Pterygoplichthys pardalis (Castelnau, 1855) (Loricariidae), Another Exotic Species Established in Southeastern Mexico". The Southwestern Naturalist 52 (1): 141–144. doi:10.1894/0038-4909(2007)52[141:ASCPPC]2.0.CO;2.
- Bunkley-Williams, Lucy; Williams, Ernest H., Jr.; Lilystrom, Craig G.; Corujo-Flores, Iris; Zerbi, Alfonso J.; Aliaume, Catherine; Churchill, Timothy N. (1994). "The South American Sailfin Armored Catfish, Liposarcus multiradiatus (Hancock), a New Exotic Established in Puerto Rican Fresh Waters" (PDF). Caribbean Journal of Science 30 (1–2): 90–94. Retrieved 2009-06-25.
- Liang, Shih-Hsiung; Wu, Hsiao-Ping; Shieh, Bao-Sen (2005). "Size Structure, Reproductive Phenology, and Sex Ratio of an Exotic Armored Catfish (Liposarcus multiradiatus) in the Kaoping River of Southern Taiwan" (PDF). Zoological Studies 44 (2): 252–259. Retrieved 2009-06-25.