Friday, March 31, 2017

[Ichthyology • 2017] Aphanotorulus rubrocauda • A New Species of Aphanotorulus (Siluriformes: Loricariidae) from the rio Aripuanã basin, Brazil

Aphanotorulus rubrocauda Oliveira, Py-Daniel & Zawadzki, 2017 
Aphanotorulus emarginatus (Valenciennes, 1840)

Aphanotorulus rubrocauda 
Oliveira, Py-Daniel & Zawadzki, 2017 


The cis-Andean genus Aphanotorulus was recently revised and comprises six valid species: A. ammophilusAemarginatusAgomesiAhorridusAphrixosoma and Aunicolor. Herein, a new species is described from tributaries of the rio Aripuanã basin, in Amazonas and Mato Grosso states, Brazil. The new species is easily distinguished from congeners by its color pattern: caudal fin with upper lobe mostly hyaline with dark spots along rays and membranes, and lower lobe red and without dark spots; and absence of dark spots in the lateral series of mid-ventral plates.

Keywords: Amazon basin; Fishes; Hypostominae; Taxonomy

Fig. 2 Lateral view of Aphanotorulus rubrocauda, MNRJ 37551, paratype, 118.6 mm SL, Brazil, Mato Grosso State, Aripuanã Municipality, rio Aripuanã basin, 500 meters downstream of the rapids of Dardanelos waterfalls. Photographed alive by Fabio Pupo.
 Fig. 3 Lateral view of Aphanotorulus emarginatus, NUP 17748, 257.3 mm SL, Brazil, Amazonas State, Parintins Municipality, Paraná do Ramos, rio Amazon basin. Photographed alive by Hugmar Pains da Silva. 

Diagnosis. Aphanotorulus rubrocauda can be distinguished from all other species of Aphanotorulus by its color pattern: having a uniformly red colored lower caudal-fin lobe (vs. lower lobe of caudal fin with dark spots on creamy colored background), by the absence of dark spots on the posterior half of mid-ventral lateral plate series (vs. presence of dark spots in all lateral plate series). Additionally, Aphanotorulus rubrocauda is distinguished from congeners by having more premaxillary teeth (32-65 per ramus, mean = 45; vs. 15-34, mean = 24) and dentary teeth (30-63 per ramus, mean = 44; vs. 14-34, mean = 25). Aphanotorulus rubrocauda further differs from A. emarginatus by having small round dark spots (vs. dark large and elongated spots) (Fig. 3).

Fig. 1 Holotype of Aphanotorulus rubrocauda, INPA 33666, 150.5 mm SL, Brazil, Amazonas State, Apuí Municipality, Resex do Guariba, rio Aripuanã drainage, tributary of the rio Madeira basin, in lateral, dorsal, and ventral views. 

Andreza S. Oliveira, Lúcia Rapp Py-Daniel and Cláudio H. Zawadzki. 2017. A New Species of Aphanotorulus (Siluriformes: Loricariidae) from the rio Aripuanã basin, Brazil. Neotropical Ichthyology. 15(1);  e160034.  DOI: 10.1590/1982-0224-20160034

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