Microwear Analysis Research Articles

Feeding Ecology in Oligocene Mylodontoid Sloths (Mammalia, Xenarthra) as Revealed by Orthodentine Microwear Analysis

Recently, dental microwear analysis has been successfully employed to xenarthran teeth. Here, we present new data on use wear features on 16 molariforms of Orophodon hapaloides and Octodontotherium grande. These taxa count among the earliest sloths and are known from the Deseadan SALMA (late Oligocene). Modern phylogenetic analyses classify Octodontotherium and Orophodon within Mylodontoidea with whom they share lobate cheek teeth with an outer layer of cementum and a thick layer of orthodentine. Similar target areas of 100μm2 were analyzed on the orthodentine surface of each tooth by stereomicroscopic microwear and by SEM microwear. Results were unlike those of extant sloths (stereomicroscopic microwear: Bradypus, Choloepus) and published data from fossil sloths (SEM microwear: Acratocnus, Megalonyx, Megatherium, Thinobadistes); thus, both approaches independently indicate a different feeding ecology for the Oligocene taxa. The unique microwear results suggest that both taxa fed on plant material with low to moderate intrinsic toughness (foliage, twigs) but also proposes intake of tougher food items (e.g., seeds). Frequent gouging of the tooth surfaces can be explained by exogenous influence on microwear, such as possible intake of abrasive grit. We suggest an unspecialized herbivorous diet for Octodontotherium and Orophodon utilizing diverse food resources of their habitat. These interpretations support the reconstruction of (1) Deseadan environments as open habitats with spreading savannas/grasslands and (2) both taxa as wide-muzzled bulk feeders at ground level.

On wedges and bones: Archaeological studies of use-wear and residue analysis from Late Holocene occupations in the Southern Pampean Hills (Alero Deodoro Roca, Córdoba, Argentina)

The aim of this paper is to present the results of complementary studies on a type of lithic tool: the small wedge, trying to understand their use and, particularly, the kind of worked material during Late Holocene times in the central region of Argentina (ADR archaeological site). FT-IR spectroscopy on residue recovered from tools edge surfaces and functional analysis of microwear were used as a crosscheck methodology for integrated analysis, including some experimental data. According with the analytical results, we propose that this type of instrument was used either as a controlled way to split camelid phalanges to use them as raw material for tool manufacture or marrow extraction.

Polished greenstone celt caches from Ceibal: the development of Maya public rituals

Abstract

Functional morphology, biomechanics and the retrodiction of early hominin diets

A fundamental axiom that underlies evolutionary biomechanics maintains that natural selection has adapted skeletal and dental morphologies to facilitate function in intelligible ways. Because selection is held to result in the improvement of functional design, it is thought possible to predict the adaptive significance of a morphological feature from a design criterion. This rationale has been widely applied to the interpretation of morphological complexes in the paleontological record for which no strict extant analogues exist. In particular, biomechanical models have been used to infer the dietary habits of extinct hominin taxa from aspects of craniodental morphology. Many of these models are hampered by missing data and loosely justified assumptions. Craniodental morphologies may indicate more about what an extinct species was capable of processing intra-orally – and probably more about its phylogenetic history – than the constitution of its diet. Even a dedicated leaf-eating hominin cannot be expected to have possessed bilophodont molars. The dietary retrodictions based on comparative anatomical that have been proffered for Plio-Pleistocene hominin species are reviewed here. We argue that the application of finite element analysis to these fossils has not revealed convincing evidence of specific feeding behaviors. Indeed, the conclusions from these biomechanical models are often incongruent with data from stable light isotopes, microwear and phytolith analysis; nor do they conform with observations on the dietary repertoires and feeding behaviors of extant primates. For example, the sooty mangabey (Cercocebus atys) is a committed hard object feeder, but suffers no deleterious consequences from the “poor design” of its facial skeleton for processing hard foods. Because primates are adept at behaviorally circumventing mechanical problems, it is perhaps useful to consider the breadth of any fossil hominin's feeding repertoire in the context of behaviors that enable mechanical problems to be dealt with prior to ingestion.

Description and microwear analysis of Clovis artifacts on a glacially-deposited secondary chert source near the Hartley Mastodon discovery, Columbiana County, Northeastern Ohio, U.S.A.

Five Clovis lithic artifacts were found in a plowed farm field just north of an unnamed tributary of the Mahoning River, Columbiana County, Northeast Ohio, approximately 700m northeast of the Hartley Mastodon discovery. These artifacts include the base of a Clovis fluted projectile point, a preform base with a prepared fluting “nipple”, a large flake, a biface tip, and a biface mid-section. We present here basic artifact morphometrics; observations involving stone tool raw material, production, and discard; microwear analysis; and stone-source-to-site straight-line and least-cost distances. Overall, our results are relevant to two discussion points. First, there is currently no strong evidence linking the five Clovis stone tools to the Hartley Mastodon. Second, the area in which the five artifacts were found would have been attractive to Clovis Paleoindians for a variety of reasons, not least of which is that the immediate area is a glacially-deposited secondary chert source.

Tooth wear and diets of extant and fossil xenarthrans (Mammalia, Xenarthra) – Applying a new mesowear approach

Xenarthrans comprised an ecologically significant and diverse group of small to gigantic sized terrestrial insectivorous, omnivorous and herbivorous mammals during the Cenozoic in South America and during the Pleistocene in North America. Their peculiar tooth morphology has proven to be challenging for palaeodietary analyses of this group. Here we introduce a new approach to this problem by utilising the recently developed mesowear angle analysis for xenarthran palaeodietary analyses. The method is based on recording the relief of worn teeth as angles measured from the occlusal surfaces. We compare our results with other lines of evidence of extant and fossil xenarthran diets, based on direct observation, orthodentine microwear analyses and analyses of fossilised faecal material. Our results support previous findings and hypotheses on fossil xenarthran diets, but also provide new information on the diversity of dietary preferences in the diverse assemblages of large Pleistocene xenarthrans such as ground sloths and glyptodonts.

Buccal dental microwear texture and catarrhine diets.

Two-dimensional dental microwear analyses on occlusal and nonocclusal enamel surfaces have been widely applied to reconstruct the feeding behaviors of extant primates and to infer ecological adaptations in fossil hominins. To date, analyses of dental microwear texture, using three-dimensional, Scale-Sensitive Fractal Analysis approaches has only been applied to occlusal surfaces. Here, for the first time, we apply this 3D proxy to buccal enamel surfaces of catarrhine primates of known feeding ecologies to assess the utility of nonocclusal microwear texture variables as indicators of dietary habits. Buccal microwear texture attributes were collected from high-resolution second molar casts in a sample of seven extant African catarrhine taxa with differing dietary behaviors. A white-light confocal microscope with a 100× objective lens was used to record six microwear texture variables that assess complexity, anisotropy, heterogeneity, and textural fill volume. The physical properties and variation in hardness of ingested foods is reflected by significant differences in the microwear variables on buccal enamel surfaces between species, which is in agreement with early reports using 2D microwear signatures of the same samples. Species that consume hard brittle items showed high buccal enamel complexity and low anisotropy values, while folivorous species that consume tough foods revealed high anisotropy and low complexity enamel patterns. Buccal microwear texture analysis on enamel surfaces clearly reflects diet-related variation in nonhuman primates. Our findings indicate that microwear texture attributes on nonworking enamel surfaces provide an alternative procedure for reconstructing dietary behavior when wear facets on occlusal surfaces are lacking.

Gazelle seasonal mobility in the Jordanian steppe: The use of dental isotopes and microwear as environmental markers, applied to Epipalaeolithic Kharaneh IV

The Early/Middle Epipalaeolithic aggregation site of Kharaneh IV in the east Jordan steppe is one of the largest of the period, showing repeated use, high degrees of site investment, and relatively prolonged periods of occupation. Hunters relied heavily on the single prey species, Gazella subgutturosa. This paper reports on isotopic analyses of gazelle teeth, drawn from the Kharaneh IV assemblage, to explore the seasonal and spatial distribution of gazelle in life and examine models of long-distance seasonal gazelle migrations. Dental microwear analysis is also employed to assess hunting seasons.Results from sequential isotope analyses of 11 Epipalaeolithic gazelle molars show that, with one exception, gazelle did not move seasonally from the limestone steppe onto other geologies, nor did they seasonally relocate to areas with different climate regimes. Rather, seasonal herd mobility seems to have been local, meaning animals would have been available in the vicinity of Kharaneh IV year-round. Results from 19 microwear analyses show some gazelle to have died in spring when grass graze was available, whilst others had been browsing around their time of death, indicating non-spring hunting. Microwear evidence thus suggests gazelle were hunted in more than one restricted season. The implications of these new datasets for hunter-gatherer use of the steppe, and potential hunting methods, is highlighted.

Challenges for microwear analysis of figurative shell ornaments from pre-Colonial Venezuela

Figurative ornaments displaying biomorphic and geometric designs have often been recovered from pre-Colonial sites in the Caribbean and northern South America. Such artefacts are held in museum and private collections, but often have not been the focus of systematic research. On the other hand, recent research into ornaments worldwide has focused on simple beads and automorphic shell ornaments. In this article, microwear analysis is used to assess technologies of production and use-wear of figurative shell ornaments from north-central Venezuela. It is our goal to reflect on the challenges posed by such collections, in terms of reproducibility of traces through experiments, post-depositional and curatorial modifications, and the complexity of past attachment configurations. The underlying question is how to deal with the limitations posed by the very nature of the studied collection in terms of preservation and of the high skill required in the reproduction of figurative artefacts.

A Neanderthal deciduous human molar with incipient carious infection from the Middle Palaeolithic De Nadale cave, Italy.

The aim of the study is the assessment of Nadale 1, a Neanderthal deciduous tooth recently discovered in Northeastern Italy in the De Nadale cave (Middle Palaeolithic). Together with the clear archaeological context of the site, this study brings new insight on Neanderthal behavior and dental morphological variability. We used microCT data to provide a morphological description and morphometric analysis (diameter measurements and dental tissue volumes) of the Nadale 1 human tooth. Microwear analysis, taphonomical investigation and caries identification were performed using a stereomicroscope and Scanning Electron Microscope. In terms of morphology (i.e., incipient tuberculum molare, marked mesial marginal ridge and well-developed mid-trigonid crest connecting the protoconid and the metaconid, deep anterior fovea) and size, Nadale 1 presents features frequently observed in Neanderthal lower first deciduous molars. Microscope investigations reveal the presence of a small pit which could be correlated to an incipient caries. Nadale 1 expands the Italian Middle Palaeolithic fossil record and provides further information on Neanderthal dm1s in terms of dimensional and morphological variability. Furthermore, the presence of an incipient caries brings further data on Neanderthal diet.

Paleoenvironment in East Java during the last 25,000 years as inferred from bovid and cervid dental wear analyses

This paper reports the results of dental mesowear and microwear analyses of bovid and cervid specimens recovered from Late Pleistocene to Middle Holocene deposits of Braholo Cave and Song Terus in Eastern Java. The aim is to infer ungulate dietary traits from dental wear signatures and gain insights regarding the paleoenvironment of the region during the last 25,000years, a period of drastic climatic fluctuations. We considered three cervid (Rusa, Axis and Muntiacus muntjak) and two bovid (Bubalus and Bos javanicus) taxa in the analyses. Results from both cave sites suggest that the Pleistocene-Holocene transition was accompanied by expansion of rainforests as evidenced by the predominance of species that had a browsing or browse-dominated mixed diet. However some of the taxa examined exhibited strong grazing signatures indicative of the continued presence of patches of grasslands up to the Mid-Holocene. Dental wear signatures of specimens from layers dating to the Last Glacial Maximum (LGM) suggest a mosaic environment dominated by grasslands. In Braholo Cave, we observed discrepancies between the mesowear and microwear signatures in specimens dating to the LGM and we take this as evidence of seasonality during this period. The results of the study provide important information on the environments encountered by the hunter-gatherer communities that lived in East Java in periods of climatic change.

The use of fan scrapers: Microwear evidence from Late Pottery Neolithic and Early Bronze Age, Ein Zippori, Israel

The results of a microwear analysis of samples of fan scrapers and fan scrapers spalls from late Pottery Neolithic (PN) and Early Bronze Age (EBA) occupation layers at Ein Zippori, Lower Galilee, Israel are presented. The goal of the microwear analysis was to determine the function of the fan scrapers and compare the visible usewear on the scrapers found in late PN and EBA lithic assemblages. The results indicate that during both periods most of the fan scrapers were used to skin and butcher animals, while some were also used for hide processing and bone working. The working edges of the fan scrapers had sharp, moderate, or steep edge-angles, and different edges were used for different tasks. Edges with microwear from scraping meat, bone, and hides (including some hides that may have been treated with abrasives) had steep edge-angles, while there were moderate or sharp edge-angles on the edges of fan scrapers used for cutting. Two sub-types of fan scrapers were identified, flat cortex fan scrapers (FCFS), and cortical fan scrapers (CFS) with convex dorsal faces. The CFS were abundant in PN contexts, while the FCFS were more common in EBA layers. However both of the sub-types had similar microwear traces.

Design and Function of Lowe and Sawmill Points from the Preceramic Period of Belize

To date, 81 stemmed and barbed preceramic (Archaic) points (8000–900 B.C.) have been identified in Belize. Fifty-four are Lowe points; 21 are Sawmill points. Four more are provisionally classified as Allspice and two as Ya’axche’ points. These stemmed bifaces are frequently beveled on alternate-opposite edges and demonstrate variable degrees of resharpening and reworking, which affects blade shape and tool size. Numerous functions have been attributed to these artifacts; specifically, they have been called spear points, dart points, harpoons, and knives. Metric data from these bifaces, limited macrowear and microwear analyses, and design features, such as barbs and alternate-opposite edge beveling, have been used to interpret likely tool functions. Results suggest that Lowe points were affixed to throwing/thrusting spears and also served as knives, whereas the Sawmill points were used as spear-thrower dart points and as knives. New dating information suggests that alternate-opposite edge beveling and consequently beveled bifaces may be much older than 2500–1900 B.C., which is the date currently assigned to these specimens.

Tooth wear as a means to quantify intra-specific variations in diet and chewing movements.

In mammals, tooth function, and its efficiency, depends both on the mechanical properties of the food and on chewing dynamics. These aspects have rarely been studied in combination and/or at the intra-specific level. Here we applied 3D dental surface texture analysis to a sample of field voles (Microtus agrestis) trapped from Finnish Lapland at different seasons and localities to test for inter-population variations. We also explored intra-individual variation in chewing dynamics by analysing two facets on the second upper molars. Our results confirm that the two localities have similar environments and that the voles feed on the same items there. On the other hand, the texture data suggest that diets are seasonally variable, probably due to varying concentrations of abrasives. Lastly, the textures on the buccal facets are more isotropic and their direction deviates more from the mesial chewing direction than the lingual facets. We interpret these results as reflecting food, rather than chewing, movements, where food particles are more guided on the lingual side of the molars. This has implications for the application of dental microwear analysis to fossils: only homologous facets can be compared, even when the molar row seems to constitute a functional unit.

The record of camelids (Artiodactyla, Camelidae) from the Valsequillo Basin, late Pleistocene of Puebla State, Central Mexico: taxonomy, diet, and geographic distribution

Dental and postcranial fossil material referable to camelids, which has been recovered from Quaternary deposits that outcrop in the Valsequillo Basin, Puebla State, central Mexico, is formally described. A comparative study indicates the presence of two species of camelids, including Hemiauchenia macrocephala and Camelops hesternus. The sample referable to H. macrocephala includes maxillary and mandibular fragments, isolated teeth, and several postcranial remains (astragalus, metapodials, and proximal phalanges), which show the following diagnostic features of the species: molariforms covered by a layer of cementum; a mandible increasing in depth from p4 to m3; p4 triangular in outline; long and slender metapodials; and proximal phalanges with a W-shaped suspensory ligament scar. The sample referable to C. hesternus is represented by maxillary and mandibular fragments, isolated teeth, and metapodials, sharing with the species its large size; P4 quadrate in outline; p4 triangular in outline and simply folded; and a mandible that is significantly deeper from p4 to m3. A microwear analysis was performed in order to characterize the diet of studied samples, indicating a browser and mixed feeding behavior in H. macrocephala and C. hesternus respectively. The differences in size and trophic regimes in these species should explained the resource partitioning between them. In the late Pleistocene these camelids were common in Mexican sites between the 19°-25° N, and the record from the Valsequillo Basin is one of the few sites where both species have been reported.

Convergent Traits in Mammals Associated with Divergent Behaviors: the Case of the Continuous Dental Replacement in Rock-Wallabies and African Mole-Rats

The study of convergences in mammals is crucial to understand the evolutionary processes underlying the origin of shared traits. A classic example is the independent evolution in the pygmy rock-wallaby, the silvery mole-rat, and manatees of continuous dental replacement to compensate for high dental wear. The origins of continuous dental replacement in mammals remain unresolved. As the functional study of a trait may permit pinpointing the adaptive nature of its independent evolution, we aimed at comparing first the morpho-functional characteristics of the masticatory apparatus between the pygmy rock-wallaby and their closest relatives, and then with some published data on the silvery mole-rat. 3D geometric morphometric and biomechanical analyses were complemented by dental microwear analyses. Our results showed that the pygmy rock-wallaby clearly departs from its relatives in having a wider skull, a shorter snout, and a dentition situated more distally. These cranial modifications, previously observed in the silvery mole-rat, are probably linked with a neotenic development. Because of higher developmental constraints on marsupial skulls, such adjustment in the pygmy rock-wallaby may have improved the force generated by adductor muscles at molars for comminution of tough and abrasive plants. In contrast, the strong attrition combined with the ingestion of dust during high activity of digging and feeding might contribute to both molar damage and high wear in the silvery mole-rat. Our results stress the importance of combining morphological, developmental, and functional data to show that different behaviors related to ecology can explain the convergent occurrence of continuous dental replacement in mammals.

The Function of Late Neolithic Long Blades and Daggers in Western Europe: An Assessment Based on Use-Wear Analysis of Grand-Pressigny Flint Productions

From the fourth millennium bc onward, flint dagger and long-blade workshops developed throughout Europe. Upper Turonian flint from the Grand-Pressigny region (western-central France) is one of the most emblematic examples of this type of lithic production from the end of the Neolithic. The function of long blades is poorly known and subject to debate. A sample of long blades and daggers was thus selected for microwear analysis, in order to record the technical tool functions of these remarkable productions from the end of the West European Neolithic. The main aim of this study is to determine whether these artifacts show any traces coming from use as tools for ordinary daily tasks, or whether they do not show wear-traces and could be interpreted as socially valued objects with no technical utility.

An examination of the dietary habits of Platybelodon grangeri from the Linxia Basin of China: Evidence from dental microwear of molar teeth and tusks

The paleodiet of shovel-tusked gomphotheres from the upper middle Miocene Hujialiang Formation of the Linxia Basin (Gansu Province, China) was assessed via molar microwear analysis of dental enamel. Both adults and an ontogenetic series of individuals of Platybelodon grangeri with assigned dental ages estimated via comparison of eruption and wear to that of extant elephants were analyzed. Mandibular tusks were also examined for microscopic scars to test a long-standing hypothesis that P. grangeri used its mandibular tusks to shovel substrate. Results show a consistent browsing signal throughout all of the age classes studied. Evenso, scratch numbers are higher and scratch widths are greater in older individuals indicating that coarser browse was consumed in older versus younger individuals. Results are more similar to those of the extant forest elephant (Loxodonta cyclotis) than to other extant forms (Loxodonta africana and Elephas maximus). Mandibular tusk microwear is very fine and inconsistent with the usage of lower tusks to shovel aquatic or terrestrial substrates and more consistent with stripping vegetation than as shoveling agents.

Cores, Core-scrapers, and Bladelet Production during the Lower Magdalenian Occupations of El Mirón Cave, Cantabrian Spain

Among the defining characteristics of the Cantabrian (Spain) Lower Magdalenian (19.2–17.5 cal kya), along with portable art works, are so-called “nucleiform endscrapers.” These small cores often display one or more regularized edges that could indicate a secondary function as scrapers. Although this has been demonstrated microscopically to be the case at some sites, it is generally not true in a large sample from Level 17, a massive Lower Magdalenian horizon in El Mirón Cave on the edge of the Cantabrian Cordillera. This study synthesizes lithic typology, technology, and microwear analysis of the Level 17 lithic sample. The results indicate that understanding the absolute versus relative abundance of core endscrapers is important to classifications of Lower Magdalenian lithic assemblages, particularly in terms of inter-site tool comparisons, understanding the relative abundance of tools in relation to debitage products, and the key role of bladelet production.

Flint tools for bone and antler adzes production at the Early Mesolithic site Krzyż Wielkopolski 7 (Western Poland)

Abstract In 2003 a rich Early Mesolithic peat bog site was discover in Western Poland and subsequent interdisciplinary project let to recognise the site as one of the richest North European Plain occupation from the point of view of the organic materials it delivered. A set of technological and typological analyses of find material, supplemented by palaeoenvironmental studies and almost 50 AMS radiocarbon datings suggest an affinity of the Mesolithic occupation with the early Duvensee/Komornica culture with probable short episode of the Maglemose culture group presence in the Boreal period. A considerable number of organic artefacts made on the spot accompanied by the Early Mesolithic lithic assemblage allow a direct on-the-spot confrontation of traces recorded on bone and antler tools and on production wastes with lithic assemblage that served for their manufacturing on different stages of the production cycle. In order to verify which tools and in what ways served for elaboration of bone and antler a selected sample of flint artefacts were subjected to micro-wear analysis. As a result a number of typologically different tools were identified, used especially for scraping. Single tools only were used for cutting, reaming, grooving, chiseling and drilling. Not always it goes along with the technological observations made during the analysis of antler and bone tools itself. Picks and flake axes, numerous within the lithic assemblage, were relatively often used for nicking in the process of antler tools' manufacturing. Technological analysis of organic material reveals that bone and antler tool manufacturing was a specialized chain of operations but not all the stages of production are manifested in the analysed material.