| Cetopsidium | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Siluriformes |
| Family: | Cetopsidae |
| Subfamily: | Cetopsinae |
| Genus: | Cetopsidium Vari, Ferraris & de Pinna, 2005 |
| Type species | |
| Pseudocetopsis orientale Vari, Ferraris & Keith, 2003 | |
Cetopsidium is a genus of catfishes (order Siluriformes) of the family Cetopsidae.
Cetopsidium was described in 2005, its name coming from the Cetopsis , the first described cetopsid genus, and idium which means diminutive, in reference to the relatively small size of Cetopsidium species. Three existing species were transferred to this genus and three new species were described. [1] In 2009 a new species, Cetopsidium soniae, was described bringing the number of species in the genus to seven. [2]
There are currently seven recognized species in this genus: [3]
Fishes of this genus are found in the rivers of northern South America.
The combination of the presence of a dorsal fin with an ossified spinelet and the presence of pectoral-fin and dorsal-fin spines distinguishes the species of Cetopsidium from all other genera in the Cetopsinae. A lateral line extending to over the posterior portion of the base of the anal fin but falling short of the caudal peduncle is also unique in this genus; the lateral line is usually longer than this, though it is shorter in two species of Denticetopsis . Cetopsidium species have mental barbels extending posteriorly beyond the rear margin of the opercle and a deeply forked, symmetrical caudal-fin margin with the tips of the lobes slightly blunt or rounded. [1]
The body is elongate to moderately robust; anteriorly the body is not compressed much, but becomes progressively compressed posteriorly. The lateral line is incomplete, unbranched, and midlateral. In most species the dorsal profile is straight, though it may be slightly convex from the head to the dorsal fin origin in some species. The ventral profile is slightly convex at the abdomen but is straight posteriorly. The caudal peduncle depth is approximately equal to its length in most species, though the depth is less than the length in C. roae and greater in C. orientale. The eyes are placed on the sides of the head and are visible from above, but not from below. The mouth is subterminal and its width is anywhere between 40–60% of the head length. They have three pairs of barbels, one pair of maxillary barbels and two pairs of mental barbels; the medial mental barbels are slightly shorter than the lateral mental barbels, which are in turn slightly shorter than the slender maxillary barbels. The anal fin is moderately long, beginning about halfway down the body, with the posterior-most anal fin rays with a slight, membranous attachment to the body. The pelvic fins are usually small. The first pectoral fin ray is spinous and is slightly longer than one-half the length of the first branched ray; however, the spine may have a prolonged distal filament in mature males. [1]
Sexual dimorphism is observed in C. ferreirai, C. morenoi, C. orientale, and C. pemon, but not in C. minutum or C. roae. Presumed mature males have the first ray of the dorsal and pectoral fins extended into filaments except in C. ferreirai. Also, the anal fin has a broadly convex margin rather than a straight margin. [1]
Cetopsidium species are smaller than Cetopsis species, growing to only 3.1–5.8 centimetres (1.2–2.3 inches) SL. [3]
The Cetopsidae are a small family of catfishes, commonly called the whale catfishes.
The stream catfishes comprise the family Akysidae of catfishes.
Callichthys serralabium is a tropical freshwater fish belonging to the Callichthyinae sub-family of the family Callichthyidae.
Physopyxis is a genus of thorny catfishes native to tropical South America.
Auchenipterichthys is a genus of driftwood catfishes found in South America.
Helogenes is a genus of whale catfish found in tropical South America.
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.
Pygidianops is a genus of pencil catfishes native to South America.
Cetopsis is a genus of catfishes of the family Cetopsidae.
Paraplotosus is a genus of catfishes native to Australasia and South-east Asia.
Entomocorus is a genus of catfishes of the family Auchenipteridae.
Auchenipterus is a genus of driftwood catfishes.
Denticetopsis praecox is a species of whale catfish endemic to Venezuela where it is known from the Baria River of the upper Rio Negro basin. This species grows to a length of 5.3 cm.
Denticetopsis royeroi is a species of whale catfish endemic to Venezuela where it is only known from the holotype collected in a tributary to the upper Rio Negro. This species grows to a length of 1.8 cm.
Deuterodon pelecus is a species of characid fish from Brazil. It can be distinguished from other species by: its body depth ; its short and pointed snout smaller than the orbital diameter; and a reduced number of branched anal fin rays. D. pelecus also differs from members of its genus by its characteristic color pattern. It possesses a single humeral spot that is constricted to the region above the lateral line; at the same time it shows a conspicuous midlateral body stripe from opercle to the caudal fin base, an autapomorphy of this precise species. Other Deuterodon species have a humeral spot that is vertically or horizontally elongate and have the midlateral stripe becoming faint near that humeral spot. The species name is derived from the Greek pelekus, meaning "axe", referring to the pigmentation shape resulting from the adjoinment of the humeral spot with the midlateral stripe.
Guyanancistrus nassauensis is a species of catfish belonging to the family Loricariidae, the suckermouth armored catfishes. It is discovered in 2005 and formally described in 2018. G. nassauensis is a rare species, highly endemic to the Nassau Mountains in Suriname, and is threatened with extinction by proposed or ongoing mining activities.
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.