100 Ma sweat bee nests: Early and rapid co-diversification of crown bees and flowering plants.

100 Ma sweat bee nests reported herein are the oldest evidence of crown bees. A new phylogeny for short-tongued bees, calibrated with these nests dated with 40Ar/39Ar, attests for the first time for a late Albian rapid diversification of bees along with angiosperms. Such hypothesis lacked paleontological support until this study. The new ichnospecies Cellicalichnus krausei, which was found along with wasp trace fossils and new beetle trace fossils in the Castillo Formation of Patagonia, represents typical Halictini nests composed of sessile cells that are attached to main tunnels. According to geological, paleosol, paleobotanical, and ichnological data, bees, and angiosperms cohabited in an inland and dry environment comparable to an open dry woodland or savanna, under warm-temperate and semiarid-subhumid climate, in the Southern Hemisphere by the Albian.

New primate locality from the early Miocene of Patagonia, Argentina.

OBJECTIVES: The purpose of this work is to present a new primate locality with evidence that increases the knowledge on the radiation of the extinct platyrrhine primates. MATERIALS AND METHODS: We studied the new specimen and compared it to specimens identified as Mazzonicebus almendrae. RESULTS: The new first and second molars were comparable to Mazzonicebus almendrae in all morphological details, allowing us to allocate the new specimen to M. almendrae and add comments on morphological variation in this species regarding the orientation of the labial cristae and development of the anterolingual cingulum. This new maxilla also present the first known M3 for the species. DISCUSSION: The new specimen increases our knowledge of the extinct platyrrhines from Patagonia. Their age and geographical distribution ranges from early to middle Miocene in an area between 40° to 47° of southern latitude.