Erk: Devil's Hole Pupfish Might be "Man Made"

Evaluating an icon of population persistence: the Devil's Hole pupfish

Authors:

Reed et al

Abstract:

The Devil's Hole pupfish Cyprinodon diabolis has iconic status among conservation biologists because it is one of the World's most vulnerable species. Furthermore, C. diabolis is the most widely cited example of a persistent, small, isolated vertebrate population; a chronic exception to the rule that small populations do not persist long in isolation. It is widely asserted that this species has persisted in small numbers (less than 400 adults) for 10 000–20 000 years, but this assertion has never been evaluated. Here, we analyse the time series of count data for this species, and we estimate time to coalescence from microsatellite data to evaluate this hypothesis. We conclude that mean time to extinction is approximately 360–2900 years (median 410–1800), with less than a 2.1% probability of persisting 10 000 years. Median times to coalescence varied from 217 to 2530 years, but all five approximations had wide credible intervals. Our analyses suggest that Devil's Hole pupfish colonized this pool well after the Pleistocene Lakes receded, probably within the last few hundred to few thousand years; this could have occurred through human intervention.

South America Hosted Several Cretaceous Relic Mammal Populations at Least into the Miocene Neogene

The bizarre ‘metatherians’ Groeberia and Patagonia, late surviving members of gondwanatherian mammals

Authors:

Chimento et al

Abstract:

Cenozoic mammalian faunas from South America contrast with those of the other continents by the great diversification of metatherian mammals. Among the later, a wide range of morphological disparity have been reported, and several bizarre mammals have been assigned to such clade, based mainly on biogeographical grounds. Outstanding examples of bizarre mammals referred to as Metatheria are the Eocene Groeberia and the Miocene Patagonia. Recent discoveries indicate that South America possessed a more diverse faunal composition than previously thought, and it became evident that many Mesozoic holdovers (e.g. australosphenidans, gondwanatherians and dryolestoids) surpassed the K/T boundary, thus forming part of the Cenozoic faunas. The Cenozoic taxa Patagonia and Groeberia exhibit several similarities with the Gonwanatheria, including rodent-like jaws with enlarged incisives, molariform cheek-teeth, anteriorly extended masseteric fossa and palinal mastication among other features. The inclusion of Gondwanatheria, Patagonia and Groeberia within an abarcative phylogenetic analysis resulted in close phylogenetic relationships among these taxa. Such hypothesis indicates that Cretaceous relics in the Cenozoic of South America were more diversified than previously thought.