Protocheirodon pi (Vari, 1978)
Protocheirodon pi
photo by Hoffmann, P. and M. Hoffmann

Family:  Characidae (Characins; tetras), subfamily: Cheirodontinae
Max. size:  3.1 cm SL (male/unsexed)
Environment:  pelagic; freshwater
Distribution:  South America: major river systems of the central and western portions of the Amazon basin including the Amazonas- Solimões, Purus, Madeira and Ucayali rivers.
Diagnosis:  Dorsal soft rays (total): 9-10; Anal soft rays: 47-51. Protocheirodon pi can be distinguished by possessing four synapomorphies proposed for the Cheirodontinae by Malabarba (1998): presence of a pseudotympanum, a hiatus in the body wall musculature lateral to at least a portion of the anterior chamber of the swimbladder; absence of dark humeral spot; possession of pedunculate dentition; and presence of only a single row of regularly arranged premaxillary teeth. It differs from all species of the Cheirodontinae and indeed members of the Characiformes by the unique form of the swimbladder which has a smaller rotund anterior chamber and the posteriorly chamber elaborated into two vertically elongate, side by side, slightly inclined chambers. These modifications resulted to a unique overall pi (?)-shaped structure (Ref. 109753).
Biology:  Found in marginal areas of rivers and streams, often over sandy substrates and in still backwaters (Ref. 109753).
IUCN Red List Status: Not Evaluated (N.E.) Ref. (123251)
Threat to humans:  harmless
Country info:   

Entered by: Casal, Christine Marie V. - 29.05.01
Modified by: Torres, Armi G. - 21.06.17
Checked by: Malabarba, Luiz R. - 29.05.01

Source and more info: For personal, classroom, and other internal use only. Not for publication.

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