Morphological characteristics of preparator air-scribe marks: Implications for taphonomic research

Abstract

Taphonomic analyses of bone-surface modifications can provide key insights into past biotic involvement with animal remains, as well as elucidate the context(s) of other biostratinomic (pre-burial) processes, diagenesis, excavation, preparation and storage. Such analyses, however, first require researchers to rigorously disambiguate between continuums of damage morphologies prior to attributing individual marks to specific actors and effectors (e.g., carnivore tooth, stone tool cutting edge, etc.). To date, a number of bone-modifying agents have been identified, and criteria for identifying their traces have been published. Relatively little research, however, has focused on bone-surface modifications imparted during specimen preparation. Herein we report that air scribes, small pneumatic tools commonly used for preparation in museum contexts, can generate unintentional marks that may mimic surficial modification caused by carnivores. To aid investigators in assessing the hypothesis that a mark in question is derived from air-scribe preparation activities, we provide high-resolution, detailed morphological information imaged with scanning electron microscopy (SEM). The main diagnostic characteristic of air-scribe damage is the occurrence of sequential, variously spaced, sub-millimeter scallop-like stepped bone removals. This morphology can resemble damage imparted by carnivore teeth. In contrast to marks produced by trampling, stone tools and carnivores, however, no continuous internal features, such as linear microstriations, were observed within grooves produced by the air scribe. Thus, the presence of such features can be used to disprove an air-scribe origin. A culmination of the morphological criteria presented herein, cross-cutting relationships with other surficial features (e.g., diagenetic discoloration, weathering textures), the position of occurrence, and an overall contextual framework for the assemblage is suggested for accurate identification of such traces. The ability to recognize or disprove air-scribe damage will allow researchers to confidently proceed with interpreting past biological and sedimentological interactions with animal remains.

Intraspecific facial bite marks in tyrannosaurids provide insight into sexual maturity and evolution of bird-like intersexual display

“…Similarly, the bone surface texture on the skulls of some tyrannosaurs (e.g., subcutaneous ridges of Thanatotheristes ; see Voris et al 2020) can be eliminated due to the lack of remodeled bone texture and their anastomosing nature. The shapes of marks that result from mechanical preparation (i.e., air scribe) have been documented (Wiest et al 2018), and these were also disregarded. Although lesion identification can be occasionally subjective, the location and morphology of all bite marks identified are documented in Supplementary Datasets S1 and S2 for the sake of data reproducibility.…”

Controlled chemical cleaning in paleontological preparation: the use of gels on vertebrate fossil remains from the Late Cretaceous of Spain

“…To assist this method, the cohesion of the clay can be weakened by localized soaking, but since this affects the structure of the fossil, its use as a cleaning treatment is not recommended. The use of the vibroincisor presents two common risks: its manipulation can produce marks on the surface (Wiest et al 2018) and the transmission…”

Cleaning archaeological bones: Influence of water, ethanol, and acetone on microhardness

“…Although cleaning is a necessary procedure, there is always the potential risk of introducing surface modifications. This may imply the loss of important information for subsequent research (Caldararo, 1993(Caldararo, , 2005L opez-Polín, 2012), such as taphonomic studies, and several applications that have noted the possible modifications that different cleaning treatments can introduce on archaeological bone (Bromage, 1984;Fernández-Jalvo & Marín-Monfort, 2008;Graham & Allington-Jones, 2018;Marín-Monfort et al, 2018;Valtierra et al, 2020Valtierra et al, , 2022Wiest et al, 2018).…”