A remarkable species flock of pupfishes, genus Cyprinodon, from Yucatán, Mexico

" Four species of the genus Cyprinodon occur in Laguna Chichancanab, an endorheic basin in the interior of the Yucatan Peninsula, Mexico. Three of these are described herein. Each new species has unique traits that separate it from the fourth pupfish in the lake, C. beltrani/i], and from all other known pupfishes. C. maya, n. sp., is a carnivore characterized by large size (to 100 mm TL) and stout build; C. labiosus, n. sp., has highly modified lips; and C. simus, n. sp., is a midwater planktivore with the lower jaw almost vertical. All four species live in complete sympatry throughout the basin. They most closely resemble C. vanegatus artifrons, which inhabits the margins of the Yucatan Peninsula "