The Oldest Beetle and Bee Ichnofossils from Mexico and their Paleoenvironmental Implications

ABSTRACT

Specimens of Fictovichnus gobiensis, Celliforma curvata, Celliforma rosellii, Celliforma germanica and Celliforma isp. were collected from paleosol horizons in a fluviolacustrine succession near Santiago Yolomécatl town, in northwestern Oaxaca, southern Mexico. These ichnofossils represent the oldest evidence of beetles and bees in Mexican localities. K–Ar ages and the record of the equid Miohippus assiniboiensis, an index fossil, indicate that the age of the deposits is late Eocene. Based on the presence of the insect ichnofossils, pedogenic carbonate isotopes and mammal proxies, the inferred type of vegetation present in the study area was scrubland/woodland, within subhumid to subarid conditions.

KEYWORDS:

• Eocene
• Oaxaca
• Fictovichnus gobiensis
• Celliforma ispp
• Celliforma Ichnofacies

Acknowledgments

We would like to thank academic and administrative teams of Universidad del Mar for logistical support during fieldtrips. We thank K.T. Smith, A. Merlin, K. Ayala, J. Priego, S. Jarquin and M.P. Cruz Olmedo, for their assistance during fieldtrips. Thanks to Tamás Mikes, Andreas Mulch and K.T. Smith for isotopic analyses on paleosol samples. We thank M.A. Morón-Ríos for providing literature. We appreciate the kind help of municipal representatives of Santiago Yolomécatl, especially Yolanda Reyes García. G. Ruelas-Inzunza is thanked for the revision of the written English. We thank two anonymous reviewers for their comments.

Funding

This project was partially funded by Conacyt CB-2008-01, No. 101626 and Conacyt CB-2015, No. 255883.