Pseudotocinclus
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| Pseudotocinclus intermedius Nichols, 1919 |
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Pseudotocinclus juquiae |
Pseudotocinclus is a genus of catfishes (order Siluriformes) of the family. It includes three species, P. juquiae, P. parahybae, and P. tietensis.[1]
[edit] Distribution and habitat
Species of Pseudotocinclus are found in the upper Tietê River basin in the ribeirão Grande, a tributary of the middle course of the rio Paraíba do Sul, Pindamonhangaba, in the headwaters of rio Itatinga, a coastal river of São Paulo, and in the upper and lower courses of the Juquiá River of the Ribeira de Iguape River basin, all rivers of São Paulo, Brazil.[1] Like other members of the subfamily Hypoptopomatinae, Pseudotocinclus is primarily herbivorous and is more commonly found at or near the upper portion of the water column. It lives in close association with sub-surface structures provided by submerged tree branches, aquatic macrophytes, and terrestrial grass blades growing along creek margins and extending into the water.[1]
P. tietensis occurs in many tributaries of the upper Tietê basin. It is found both in small creeks and medium size rivers such as the Paraitinga River, a tributary of the rio Tietê, where it lives grazing on semisubmersed overhanging plants. It is also found in the Rio Grande, a small sized river which drains to the Billings Dam near Vila de Paranapiacaba, Santo André. This species can be found attached to the grass along the river margin and in the middle of the river among rocks and pieces of wood in fast current water.[1]
P. parahybae is known only from the type locality, a tributary of the ribeirão Grande, rio Paraíba do Sul basin. It is a medium-size creek, 0.5–1.5 metres (1.6–4.9 ft) deep and 5.0 m (16.4 ft) wide at approximately 800 m (2600 ft) above sea level, on the slope of Serra da Mantiqueira, with very clear, well oxygenated, and fast flowing water, running mainly on stone beds.[1]
P. juquiae is known from a few localities of the Juquiá River basin. The type locality, a small creek in Juquitiba, is clear, with a slow current, mud, and in some places, sand on the bottom. Marginal vegetation includes a small area of pastures, small trees and shrubs. P. juquiae has also been found in the ribeirão Poço Grande, a tributary on the right margin of the Juquiá River; this locality, an old swamp area near the city of Juquiá, is heavily impacted by human activities, and is also used for garbage and sewage disposal.[1]
[edit] Description
The genus Pseudotocinclus can be distinguished from other genera of the subfmaily Hypoptopomatinae by the presence of a caudal peduncle that is nearly square in cross section from the posterior base of the dorsal fin to the caudal fin, as well as having 26 or more plates along the lateral line, a dorsally positioned eye, an exposed preopercle, and an abdomen covered with numerous small platelets.[1]
The presence of a small naked area on the snout tip distinguishes P. tietensis from P. parahybae and P. juquiae, which have the snout tip covered with small platelets. In addition, P. tietensis has four transverse dark-brown bands on the dorsum coalesced with the midlateral stripe instead of three as in the other two species. P. juquiae is distinguished from the other species by having a very prominent and conspicuous ring structure around the eye. The three species also differ from their congeners by meristics and morphometrics.[1]
