Coptobrycon Géry, 1966

Langeani, Francisco & Serra, Jane Piton, 2010, Coptobrycon bilineatus (Ellis, 1911) (Characiformes: Characidae): redescription and comments on its phylogenetic relationships, Neotropical Ichthyology 8 (4), pp. 727-736 : 728

Coptobrycon Géry, 1966

Figs. 1-7

Coptobrycon Géry, 1966: 226 (type-species: Hasemania bilineata Ellis, 1911 , by original designation and monotypy).

Diagnosis. Coptobrycon is easily distinguished from all other Characidae due to: a very peculiar dentary dentition, with only three, large, anterior, multicuspid and pedunculated, principal teeth in each half of the dentary ( Fig. 5 ; vs. four or more conical or cuspidate and not pedunculated teeth, except in the Cheirodontinae and Iguanodectinae , which have more than four pedunculated teeth); the absence of the nasal bone ( vs. present); the presence of a straight, dark brown stripe slightly above the base of the anal fin ( Fig. 1 ), from vertical through its origin or slightly behind, continuing through the ventral portion of the caudal peduncle up to the base of the caudal fin ( vs. absent). Furthermore, it can also be separated from all other Characidae , except Grundulus , by having the nasal pores separated by a non confluent space ( Fig. 2 ; vs. nasal pores very close and confluent); infraorbitals 4 and 6 (5, sometimes) absent ( Fig. 4 ; vs. present); infraorbital laterosensory canal greatly reduced, with pores inconspicuous or absent ( Fig. 4 ; vs. present); supraorbital laterosensory canal absent in posterior portion of the frontal ( vs. present). Other useful diagnostic characters include: up to six olfactory rosette lamellae, turned to the posterior portion of the nasal canal ( Fig. 3 ; vs. more than ten lamellae, generally more than fifteen, concentrically arranged; except in Grundulus and Xenurobrycon ); adipose fin absent ( Fig. 1 ; vs. present; except in Grundulus , Gymnocharacinus bergi , Hasemania , some Hyphessobrycon species , and Spintherobolus ).

Figures

Fig. 1. Coptobrycon bilineatus, DZSJRP 6610, 29.1 mm SL, rio Itatinga, RPPN Parque das Neblinas, Bertioga, São Paulo, Brazil.

Fig. 2. Coptobrycon bilineatus, DZSJRP 6610, 29.1 mm SL: nasal orifices.

Fig. 3. Coptobrycon bilineatus, DZSJRP 6610, 30.7 mm SL: olfactory rosettes. Scale bar = 1 mm.

Fig. 4. Coptobrycon bilineatus, infraorbital (i) series, left side, lateral view.DZSJRP 6890, 36.3 mm SL (left), and DZSJRP 6890, 28.1 mm SL (right). Scale bar = 1 mm.

Fig. 5. Coptobrycon bilineatus, DZSJRP 6890, 36.3 mm SL: premaxillary, maxillary and dentary, left side, medial (left) and lateral views (right). Scale bar = 1mm.