Burrow systems evince non-solitary geomyid rodents from the Paleogene of southern Mexico.

Rosalía Guerrero-Arenas,Eduardo Jiménez-Hidalgo,Jorge Fernando Genise,Hesham M Sallam

doi:10.1371/journal.pone.0230040

Abstract

We describe a new complex burrow system produced by geomyids in southern Mexico. Yaviichnus inyooensis igen. isp. nov. is composed of main large chambers near the top of the paleosol, from which shafts showing different morphologies and orientations radiate, some of them ending in or connected to small deeper chambers. Gregorymys spp. is proposed as the producer based on its fossorial habits, abundance in the outcrops, presence of remains inside the burrows, and paired grooves in the walls, which are compatible with the traces of geomyid incisors. The complexity of these burrows attests to an extended underground life that would have been triggered by semiarid to arid conditions. Morphological complexity also suggests that the burrows were excavated and inhabited by more than one individual, indicating that Oligocene Gregorymys of southern Mexico would be a unique gregarious geomyid.

Highlights

The behavior of burrowing has probably been present in mammals since their early origins
It is assumed that subterranean mammals exploited the underground ecotope during the global climatic transition from the middle Eocene to the early Oligocene [3]
Interconnected burrow system composed of shafts, tunnels and two types of chambers (Fig 4)

Summary

Introduction

The behavior of burrowing has probably been present in mammals since their early origins. Soil provides physical protection; it supports plants and animals that many fossorial mammals use [1]. There are several early Oligocene localities in temperate North America, but the only reported Oligocene mammalian locality from tropical North America is Santiago Yolomecatl in southern Mexico [4]. It includes a few fossorial taxa, such as Rhineura (Reptilia: Squamata), and rodents [6]; further detailed study on these burrows suggested that these structures were much more complex than Alezichnos Several specimens of G. veloxikua and G. sp. had been collected inside burrows, which were tentatively identified as Alezichnos isp. [6]; further detailed study on these burrows suggested that these structures were much more complex than Alezichnos

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Discussion

Conclusion