How to Identify Dientudo

To identify Dientudo (Oligosarcus jenynsii), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Generally silvery to olive-brown on the dorsal side, fading to a lighter, silvery-white on the ventral side. May exhibit a faint lateral stripe or scattered dark spots, especially in juveniles. Fins are typically translucent or slightly dusky.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Large, conical, and very sharp teeth, particularly prominent in the lower jaw, giving it its common name 'Dientudo' (toothy)., Elongated, fusiform body adapted for swift predatory strikes., Large mouth extending beyond the posterior margin of the eye., Adipose fin present.

Dorsal fin

Single, relatively short dorsal fin located mid-body, followed by a small adipose fin.

Tail fin

Forked caudal fin, efficient for propulsion.

Pectoral fin

Paired pectoral fins positioned low on the body.

Distinctive fins

Pelvic fins are abdominal. All fins are generally unornamented.

Identification Tips

1. 1

   Teeth

   The most distinguishing feature is its prominent, conical, and very sharp teeth, especially visible when the mouth is closed or slightly agape. These teeth are significantly larger and more robust than those of most other characins in its range.

2. 2

   Body Shape

   Its elongated, torpedo-shaped body is characteristic of a swift predator, differing from the deeper-bodied or more compressed forms of many other characids.

3. 3

   Mouth Size

   The large mouth, extending well past the eye, is another key identifier, indicating its piscivorous diet.

4. 4

   Adipose Fin

   The presence of a small adipose fin between the dorsal and caudal fins confirms its placement within the Characidae family, though this is common to many species.

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