Mammal tooth traces in a ferruginous cave in southeastern Brazil and their relevance to cave legal protection.

André G Vasconcelos,Jonathas S Bittencourt,Augusto S Auler

doi:10.1590/0001-3765201920180861

André G Vasconcelos, Jonathas S Bittencourt + Show 1 more

Open Access

https://doi.org/10.1590/0001-3765201920180861

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Abstract

We describe the first occurrence of biogenic traces made by mammals within an iron formation cave located in the Serra da Ferrugem Ridge, in Southeastern Brazil. These bioerosions are tooth traces produced in boulders, walls and floor within the cave. The traces occur as sets of two or more grooves, which are highly variable in size. The grooves were compared to tooth traces artificially produced by imprinting the incisors of different mammal species collected in the cave region on soft clay. Among those, the following taxa are potential tracemakers: Akodon sp., Oligoryzomys sp., Necromys lasiurus, Rhipidomys mastacalis, Oecomys gr. concolor, Trinomys moojeni, and Hydrochoerus hydrochaeris. The age of the traces is unknown; therefore, any discussion on its fossil nature is circumstantial. Regardless of its relevance to paleontology, the presence of ichnological features should be considered as an additional cave value, according to the current Brazilian legislation regarding cave protection.

Highlights

Fossil and extant biogenic structures within caves include chemically-induced erosional surfaces and relief construction, such as tubes, burrows, pits, tunnels and scratch traces, variously produced by distinct types of organisms, notably microbial decomposers, plant roots, and assorted invertebrates and vertebrates (Holsinger and Dickson 1977, Macdonald and Terrel-Nield 1991, Lockley and Meyer 2000, Santucci et al 2001, Lamprinou et al 2009, Jones 2010, Karkanas and Goldberg 2013)
Among the best-preserved traces, quantitative parameters, such as length and width, were taken for 75 traces. Based on their shape and size, the traces were separated into two morphotypes: Figure 4 - the black stars indicate the tooth traces in the cave CMN-0022, which are mostly concentrated on the western wall at the northern entrance
We describe the first occurrence of biogenic alterations made by mammal teeth within an iron formation cave in the Serpentina Ridge, at Minas Gerais state, southeastern Brazil

Summary

Introduction

Fossil and extant biogenic structures within caves include chemically-induced erosional surfaces and relief construction, such as tubes, burrows, pits, tunnels and scratch traces, variously produced by distinct types of organisms, notably microbial decomposers, plant roots, and assorted invertebrates and vertebrates (Holsinger and Dickson 1977, Macdonald and Terrel-Nield 1991, Lockley and Meyer 2000, Santucci et al 2001, Lamprinou et al 2009, Jones 2010, Karkanas and Goldberg 2013). Several studies have demonstrated the role of biological activity as chemical modifiers of caves, including mainly microbial-induced substrate weathering or speleothem construction (Jones 2010 for review), and erosion by the input of metabolic residues, such as carbon dioxide, water and of bat and bird guano (Piccini et al 2007, Lundberg and McFarlane 2012). The direct mechanical weathering of caves by organisms is frequently neglected, rendering an equivocal irrelevance to its role as substrate shaper

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