| Pygidianops | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Siluriformes |
| Family: | Trichomycteridae |
| Subfamily: | Glanapteryginae |
| Genus: | Pygidianops Myers, 1944 |
| Type species | |
| Pygidianops eigenmanni Myers, 1944 | |
Pygidianops is a genus of pencil catfishes native to South America.
There are currently four recognized species in this genus: [1]
P. eigenmanni is from the Rio Negro basin in Brazil. [2] P. cuao is known only from Cuao River drainage basin. P. magoi is known only from lower Orinoco mainstem between Ciudad Bolívar and Barrancas in Venezuela. [3]
Species of Pygidianops share the extreme reduction of pigmentation, loss of the dorsal fin, the loss or extreme reduction of pectoral fins, a reduced lateral line, and the reduction or complete loss of eyes in some species. These fish are markedly miniaturized, yet retain a relatively well-ossified skeleton comparable in both bone differentiation and degree of calcification to that observed in larger trichomycterids. [3]
P. cuao is distinguished from congeners by the presence of diminutive eyes (vs. eyes absent in both other species), posterior naris absent (vs. nares bilaterally paired), and the presence of a triangular skin flap at mouth corner (vs. skin flap absent). [3] P. magoi is distinguished from all congeners by the absence of pectoral and anal fins (vs. fins present), posterior naris absent (vs. present, nares bilaterally paired), four laterosensory pores on the head (vs. six), and by the presence of 9–10 caudal fin rays (vs. 12–13). With all of its fins lost except the caudal fin, P. magoi represents the most extreme fin loss among ostariophysans. [3] P. eigenmanni lacks eyes but has its anal and pectoral fins. [3]
Airbreathing catfish comprise the family Clariidae of the order Siluriformes. Sixteen genera and about 117 species of clariid fishes are described; all are freshwater species. Other groups of catfish also breathe air, such as the Callichthyidae and Loricariidae.
Trichomycteridae is a family of catfishes commonly known as pencil catfishes or parasitic catfishes. This family includes the candiru fish, feared by some people for its alleged habit of entering into the urethra of humans. They are one of the few parasitic chordates. Another species is the life monsefuano which was important to the Moche culture and still an important part of Peruvian cuisine.
The Cetopsidae are a small family of catfishes, commonly called the whale catfishes.
The stream catfishes comprise the family Akysidae of catfishes.
Listrura is a genus of pencil catfishes native to South America.
Phreatobius is a genus of very small catfishes from tropical South America.
Propimelodus is a genus of South American catfish of the family Pimelodidae.
Nannoptopoma is a small genus of catfishes of the family Loricariidae. This genus includes two species, N. spectabile and N. sternoptychum.
Glanapteryx is a genus of catfishes native to South America.
Cetopsidium is a genus of catfishes of the family Cetopsidae.
Paracetopsis is a genus of whale catfishes found in tropical South America.
Denticetopsis is a genus of catfishes of the family Cetopsidae.
Breitensteinia is a genus of catfishes of the family Akysidae. It includes three species.
Acrochordonichthys is a genus of catfishes of the family Akysidae. It includes ten species.
Typhlobelus is a genus of pencil catfishes native to South America.
The Glanapteryginae are a subfamily of catfishes of the family Trichomycteridae. It includes four genera, Glanapteryx, Listrura, Pygidianops, and Typhlobelus.
The Sarcoglanidinae are a subfamily of catfishes of the family Trichomycteridae. It includes six genera: Ammoglanis, Malacoglanis, Microcambeva, Sarcoglanis, Stauroglanis, and Stenolicmus.
Pseudolithoxus is a genus of suckermouth armored catfishes with five described species from the basins of the Orinoco, Casiquiare and upper Rio Negro in Venezuela. Additionally, a possibly undescribed species is known from the Trombetas and Nhamundá rivers in Brazil.
Cetopsis is a genus of catfishes of the family Cetopsidae.
Cetopsis candiru, also known as candiru, candiru açú, candiru cobra or canero, is a carnivorous species of whale catfish found in the Amazon basin of Peru, Brazil and Bolivia. Similar to Cetopsis coecutiens, Cetopsis candiru is a large species of the genus Cetopsis and a widespread scavenger, known for its voracious feeding and the habit of burrowing into the carcasses of dead animals and humans. Despite its name, it is not closely related to the bloodsucking Candiru.