
A new rheophilic South American darter (Crenuchidae: Characidium ) from the rio Juruena basin, Brazil, with comments on morphological adaptations to life in fast‐flowing waters
2020; Wiley; Volume: 97; Issue: 5 Linguagem: Inglês
10.1111/jfb.14485
ISSN1095-8649
AutoresAngela Maria Zanata, Willian Massaharu Ohara, Osvaldo Takeshi Oyakawa, Fernando César Paiva Dagosta,
Tópico(s)Fish Biology and Ecology Studies
ResumoAbstract Characidium iaquira , a new species from the upper rio Juruena, rio Tapajós basin, Brazil, is described. The new species can be promptly distinguished from all congeners by having a unique v‐shaped dark mark lying along the caudal‐fin extension, in medium‐ and large‐sized specimens, and a remarkable iridescent green colouration in life. Characidium iaquira is closely related to Characidium crandellii and Characidium declivirostre by sharing unambiguous synapomorphies such as branchiostegal membranes united to each other across the isthmus, a scaleless area extending from the isthmus to the pectoral girdle, and dermal flaps surrounding anterior and posterior naris independent, but touching each other distally. Morphological specializations of the paired fins in the three riffle‐dwellers species are discussed, including the wing‐like shape, robustness, and inclination of the pectoral fin.
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