Chirostoma
Chirostoma is a genus of Neotropical silversides from the Lerma River basin in Mexico, including lakes Chapala and Pátzcuaro. Fish in the genus collectively go by the common name charal/'charales' in their native range. They are heavily fished, but several of the species have become threatened due to habitat loss, introduced species and overfishing. Three species are considered extinct: C. bartoni, C. charari and C. compressum. Four others have not been recorded recently and may also be extinct.
Appearance and behavior
Chirostoma are generally silvery-white, pale gray-brown or dull yellowish in color, and have a long horizontal line on the side of the body. They vary in size, ranging from species that are less than long to species that can surpass. Despite the differences, there is great overlap in the food choice of these filter feeders with the main diet being composed of various small organisms such as copepods, cladocerans, rotifers, amphipods, oligochaetes, nematodes, insect larvae, and fish eggs and embryos.They are ovoviviparous and employ external fertilization. During spawning each female lays a few hundred to a few thousand eggs.
Species
There are currently 23 recognized species in this genus. Additionally, the 4 Poblana species are sometimes included in Chirostoma instead of being placed in a separate genus. Several species of Chirostoma can hybridize.Chirostoma aculeatum C. D. Barbour, 1973 Chirostoma arge Chirostoma attenuatum Meek, 1902- †Chirostoma bartoni D. S. Jordan & Evermann, 1896 Chirostoma chapalae D. S. Jordan & Snyder, 1899
- †Chirostoma charari
- †Chirostoma compressum F. de Buen, 1940Chirostoma consocium D. S. Jordan & C. L. Hubbs, 1919 Chirostoma contrerasi C. D. Barbour, 2002 Chirostoma copandaro F. de Buen, 1945Chirostoma estor D. S. Jordan, 1880 Chirostoma grandocule Chirostoma humboldtianum Chirostoma jordani Woolman, 1894 Chirostoma labarcae Meek, 1902 Chirostoma lucius Boulenger, 1900 Chirostoma melanoccus Álvarez, 1963 Chirostoma patzcuaro Meek, 1902 Chirostoma promelas D. S. Jordan & Snyder, 1899 Chirostoma reseratum Álvarez, 1963Chirostoma riojai Solórzano & Y. López, 1966 Chirostoma sphyraena Boulenger, 1900 Chirostoma zirahuen Meek, 1902