Relationships of Megaoryzomys curioi, an Extinct Cricetine Rodent (Muroidea: Muridae) from the Galápagos Islands, Ecuador

Resumen

The Relationships of Megaory¬ zomys cunoi, an Extinct Cricetine Rodent (Muroidea: Muridae) from the Galapagos Islands, Ecuador.Smithsonian Contributions to Paleobiology, number 51, 23 pages, 11 figures, 1 table, 1982.-Megaoryzomyscunoi is a thomasomyine, not an oryzomyine as previously believed.This rodent was originally de¬ scribed, from three bony fragments found in a cave on Isla Santa Cruz, Galapagos, as a new species of the Antillean oryzomyine genus Megalomys.The genus Megaoryzomys was named recently for this species, based on new material from Isla Santa Cruz.Our study of additional material indicates that Megao¬ ryzomys cunoi is not closely related to Oryzomys but is most similar to large species of Thomasomys, a genus confined to mainland South America.The Galapagos have been colonized by cricetine rodents at least three times, once by a thomasomyine and twice by oryzomyines.Of these colonists, Megaoryzomys cunoi is the most divergent from mainland relatives and thus is probably derived from the earliest immigrant.Although the time of extinction of Megaoryzomys curioi has not been determined, and it has never been recorded from life, it probably survived into historic time.Official publication datf is handslamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year.Series cover design: The triinbite Phaco/is rana Green.