Unraveling the nomenclatural puzzle of the collared and white-lipped peccaries (Mammalia, Cetartiodactyla, Tayassuidae).

The nomenclatural history of the collared and white-lipped peccaries, two well-recognized taxonomic entities, has been confusing. From the 18th century to the beginning of the 20th century, several genera were created, most of them without an explicit designation of type species. Due to differing opinions as to whether the two species should be included in a single genus or, if separate genera were recognized, which generic name should be applied to each of the two taxa, the validity of generic and specific names oscillated until even recently. This paper aims to solve these nomenclatural issues by reviewing the different taxonomic arrangements of these two peccaries and applying appropriately the International Code on Zoological Nomenclature. We contend that the valid generic name for the white-lipped peccary is Tayassu Fischer, 1814 (type Sus pecari Link, 1795), while Dicotyles Cuvier, 1816 (type Dicotyles torquatus Cuvier, 1816) is the valid genus for the collared peccary, with Pecari Reichenbach, 1835 as its junior synonym.

Formation of the Isthmus of Panama.

The formation of the Isthmus of Panama stands as one of the greatest natural events of the Cenozoic, driving profound biotic transformations on land and in the oceans. Some recent studies suggest that the Isthmus formed many millions of years earlier than the widely recognized age of approximately 3 million years ago (Ma), a result that if true would revolutionize our understanding of environmental, ecological, and evolutionary change across the Americas. To bring clarity to the question of when the Isthmus of Panama formed, we provide an exhaustive review and reanalysis of geological, paleontological, and molecular records. These independent lines of evidence converge upon a cohesive narrative of gradually emerging land and constricting seaways, with formation of the Isthmus of Panama sensu stricto around 2.8 Ma. The evidence used to support an older isthmus is inconclusive, and we caution against the uncritical acceptance of an isthmus before the Pliocene.