Epactionotus Reis & Schaefer, 1998
* evers, h.-g.; seidel, i. (2002): Wels Atlas Bd. 1: Südamerikanische Welse der Familien Loricariidae, Cetopsidae, Nematogenyidae & Trichomycteridae. - Mergus Verlag GmbH, Melle ISBN 3-88244-062-7
Epactionotus is a genus of catfish (order Siluriformes) of the family Loricariidae.
Epactionotus was first described in 1998 by Roberto E. Reis and Scott A. Schaefer, as including three species. Epactionotus is part of the tribe Otothyrini within the subfamily Hypoptopomatini. Epactionotus is sister to a clade including Eurycheilichthys, Pseudotocinclus, Microlepidogaster, Schizolecis, Otothyris, and Pseudotothyris. E. aky and E. yasi were both described in 2004.
The first three described Epactionotus species are each endemic to a very limited geographic area along the Atlantic coast of southern Brazil. E. bilineatus is endemic to the rio Maquiné, the rio Três Forquilhas and its tributaries in Rio Grande do Sul State, southern Brazil. E. itaimbezinho is endemic to two localities in the upper reaches of the rio Mampituba drainage, an isolated coastal stream situated along the border between Rio Grande do Sul and Santa Catarina States, southern Brazil. E. gracilis is endemic to the Araranguá River drainage, an isolated coastal drainage in southern Santa Catarina State. E. aky is known from the arroyos Garibaldi and Fortaleza. Both streams are headwaters of the arroyo Yabotí-Guazú, which flows into the Uruguay River, in the Misiones Province of Argentina. E. yasi is only known from the arroyo Lobo, a tributary of the Iguazu River in Argentina.
These fish are small, none surpassing 4 centimetres (1.6 in) SL. The head have longitudinal light-colored stripe markings which may extend onto the body over a base green color. The body is covered by bony plates except for a few areas. E. aky is differentiated from the other species in that it has platelets on its abdomen. E. yasi is differentiated from the other species by a vent completely covered by platelets. The adipose fin is absent. The lips are small and round and form a suckermouth. Maxillary barbels are short. Odontodes are present on the head and trunk and are generally uniform in size and distribution.
The habitats of most of these species are similar. These fish are found in shallow, small rivers or creeks with bottom composed of rocks, loose stones, and gravel (and may also include sand and mud) and clear water with slow to moderate current. The habitat of E. aky may become turbid due to rainfall. Water is usually very cold in the austral (southern) winter. Grass or other vegetation is always present on the stream margins. The fishes are usually found on leaves and stalks of marginal vegetation, frequently adhering by means of their pelvic fins. E. aky associate with Echinodorus plants and may be well hidden and difficult to see by eye. E. yasi lives among terrestrial vegetation that falls into the water.
1. ^ a b c d e f g h i j k l Reis, Roberto E.; Schaefer, Scott A. (December 21, 1998). "New Cascudinhos from Southern Brazil: Systematics, Endemism, and Relationships (Siluriformes, Loricariidae, Hypoptopomatinae)" (PDF). American Museum Novitates 3254: 1–25. http://digitallibrary.amnh.org/dspace/bitstream/2246/3154/1/N3254.pdf.
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