Scoloplax

Life-forms

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Superclassis/Classis: Actinopterygii
Classis/Subclassis: Actinopteri
Subclassis/Infraclassis: Neopterygii
Infraclassis: Teleostei
Megacohors: Osteoglossocephalai
Supercohors: Clupeocephala
Cohors: Otomorpha
Subcohors: Ostariophysi
Sectio: Otophysa
Ordo: Siluriformes

Familia: Scoloplacidae
Genus: Scoloplax
Species (6): S. baileyi – S. baskini – S. dicra – S. distolothrix – S. dolicholophia – S. empousa
Name

Scoloplax Bailey & Baskin, 1976

Gender: Feminine
Type species: Scoloplax dicra Bailey & Baskin, 1976
Type by original designation (also monotypic)

References

Bailey, R.M. & Baskin, J.N. 1976: Scoloplax dicra, a new armored catfish from the Bolivian Amazon. Occasional Papers of the Museum of Zoology, University of Michigan (674): 1–14. PDF
Rocha, R., Lazzarotto, H. & Rapp Py-Daniel, L. 2012: A New Species of Scoloplax with a Remarkable New Tooth Morphology within Loricarioidea (Siluriformes: Scoloplacidae). Copeia, 2012 (4): 670–677.

Links

Scoloplax species list in FishBase,
Froese, R. & Pauly, D. (eds.) 2023. FishBase. World Wide Web electronic publication, www.fishbase.org, version 10/2023.
Scoloplax and its species (including synonyms) in Catalog of Fishes, Eschmeyer, W.N., Fricke, R. & van der Laan, R. (eds.) 2023. Catalog of Fishes electronic version.

Vernacular names
català: Escoloplàcid
Deutsch: Stachlige Zwergwelse
日本語: スコロプラクス属
lietuvių: Dygliuotosios nykštukinės katžuvės

Scoloplax is the only genus in the catfish (order Siluriformes) family Scoloplacidae, the spiny dwarf catfishes.
Species

The six currently recognized species in this genus are:[1][2]

Scoloplax baileyi Rocha, Lazzarotto & Rapp Py-Daniel, 2012[2]
Scoloplax baskini Rocha, de Oliveira & Rapp Py-Daniel, 2008
Scoloplax dicra Bailey & Baskin, 1976
Scoloplax distolothrix Schaefer, Weitzman & Britski, 1989
Scoloplax dolicholophia Schaefer, Weitzman & Britski, 1989
Scoloplax empousa Schaefer, Weitzman & Britski, 1989 (Pantanal dwarf catfish)

Distribution

Scoloplax is distributed in South America in Peru, Bolivia, Brazil, and Paraguay.[3] S. baskini is from the small tributaries of Rio Aripuanã, Rio Madeira drainage, Amazonas State, Brazil.[4] S. dicra has the largest distribution in the Amazon basin, originating from the Amazon and Paraguay River basins.[4][5] S. distolothrix inhabits the Tocantins-Araguaia, Xingu, and Paraguay River basins.[5] S. dolicholophia is known from the Rio Negro basin in Brazil, as well as the Lake Amanã.[4] S. empousa lives in the Amazon and Paraguay-Paraná River basins.[5]
Description

Species of Scoloplax are readily distinguishable from other catfishes by the presence of a conspicuous shield-shaped rostral plate bearing numerous large and recurved odontodes.[4] These fish have three rows of odontode-bearing plates, two bilateral series and one midventral series. There is also a rostral plate with many recurved odootodes. The adipose fin is absent.[3] The greatest length reached is about 20 mm (0.79 in) SL.[3]

Scoloplax species have modified stomachs that are enlarged, thin-walled, and clear. The esophagus enters the stomach along the dorsal side just posterior to the anterior margin of the stomach; the intestine exits the stomach ventrally. A small patch of muscular tissue represents the digestive portion of the stomach, located from the entrance of the esophagus to where the intestine exits. This modified stomach may be for buoyancy control or for breathing air.[6]
Ecology

Scoloplax species are fairly common among leaf litter in clear and blackwater habitats, including oxbow lakes, backwater pools, and well-vegetated streams.[4][6]
References

Froese, Rainer and Pauly, Daniel, eds. (2012). Species of Scoloplax in FishBase. February 2012 version.
Rocha, R., Lazzarotto, H. & Rapp Py-Daniel, L. (2012): A New Species of Scoloplax with a Remarkable New Tooth Morphology within Loricarioidea (Siluriformes: Scoloplacidae). Copeia, 2012 (4): 670-677.
Nelson, Joseph S. (2006). Fishes of the World. John Wiley & Sons, Inc. ISBN 0-471-25031-7.
Rocha, Marcelo Salles; Oliveira, Renildo Ribeiro; Py-Daniel, Lúcia H. Rapp (2008). "Scoloplax baskini: a new spiny dwarf catfish from rio Aripuanã, Amazonas, Brazil (Loricarioidei: Scoloplacidae)". Neotropical Ichthyology. 6 (3): 323–328. doi:10.1590/S1679-62252008000300005.
Ferraris, Carl J. Jr. (2007). "Checklist of catfishes, recent and fossil (Osteichthyes: Siluriformes), and catalogue of siluriform primary types" (PDF). Zootaxa. 1418: 1–628. doi:10.11646/zootaxa.1418.1.1.
Armbruster, Jonathan W. (1998). "Modifications of the Digestive Tract for Holding Air in Loricariid and Scoloplacid Catfishes" (PDF). Copeia. 1998 (3): 663–675. doi:10.2307/1447796. JSTOR 1447796.