Brazilian ichthyologists Flvio Lima and Leandro Sousa have described Hemigrammus yinyang as a new tetra from the upper Rio Negro drainage.
Publishing the description in the latest issue of Aqua, International Journal of Ichthyology, the authors distinguish it from all congeners by the presence in life of an orange blotch, situated between two dark humeral blotches, immediately ahead and slightly above the posterior, darker second humeral blotch, and lacking a dark blotch on the caudal peduncle.
The new species is named in allusion to its complementary orange and black humeral blotches, which are reminiscent of the Taiji diagram, the pictorial representation of the state of undifferentiated absolute, encompassing both the yin and yang qualities.
Hemigrammus yinyang is only known from the tributaries of the middle Tiqui River, a tributary of the Uaups River in the upper Rio Negro drainage.
For more information, see the paper: Lima, FCT and LM Sousa (2009) A new species of Hemigrammus from the upper rio Negro basin, Brazil, with comments on the presence and arrangement of anal-fin hooks in Hemigrammus and related genera (Ostariophysi: Characiformes: Characidae). Aqua, International Journal of Ichthyology 15, pp. 153"168.