Eli Amson

Eli Amson
State Museum of Natural History Stuttgart | SMNS · Department of Paleontology

PhD

About

91
Publications
37,659
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Citations
Introduction
I work on the evolution of the skeleton, focusing on mammals.
Additional affiliations
March 2021 - present
State Museum of Natural History Stuttgart
Position
  • Curator - Fossil mammals
January 2018 - present
Museum für Naturkunde - Leibniz Institute for Research on Evolution and Biodiversity
Position
  • PostDoc Position
January 2016 - December 2017
Humboldt-Universität zu Berlin
Position
  • PostDoc Position

Publications

Publications (91)
Article
Full-text available
Through phenotypic plasticity, bones can change in structure and morphology, in response to physiological and biomechanical influences over the course of individual life. Changes in bones also occur in evolution as functional adaptations to the environment. In this study, we report on the evolution of bone mass increase (BMI) that occurred in the p...
Article
Full-text available
Background Sciuromorpha (squirrels and close relatives) are diverse in terms of body size and locomotor behavior. Individual species are specialized to perform climbing, gliding or digging behavior, the latter being the result of multiple independent evolutionary acquisitions. Each lifestyle involves characteristic loading patterns acting on the bo...
Article
Full-text available
Quantifying the inner structure of bones is central to various analyses dealing with the phenotypic evolution of animals with an ossified skeleton. Computed tomography allows to assess the repartition of bone tissue within an entire skeletal element. Two parameters of importance for such analyses are the global compactness (Cg) and total cross-sect...
Preprint
Full-text available
The skeleton is involved in most aspects of vertebrate life history. Previous macroevolutionary analyses have shown that structural, historical, and functional factors influence the gross morphology of bone. The inner structure of bone has, however, received comparatively little attention. Here we address this gap in our understanding of vertebrate...
Article
Full-text available
𝗕𝗮𝗰𝗸𝗴𝗿𝗼𝘂𝗻𝗱. The study of convergently acquired adaptations allows fundamental insight into life's evolutionary history. Within lepidosaur reptiles – i.e., lizards, tuatara, and snakes – a fully fossorial ('burrowing') lifestyle has independently evolved in most major clades. However, despite their con-sistent use of the skull as a digging tool, cra...
Article
Full-text available
Examples of photoluminescence (PL) are being reported with increasing frequency in a wide range of organisms from diverse ecosystems. However, the chemical basis of this PL remains poorly defined, and our understanding of its potential ecological function is still superficial. Among mammals, recent analyses have identified free-base por-phyrins as...
Article
Full-text available
Identifying ecomorphological convergence examples is a central focus in evolutionary biology. In xenarthrans, slow arboreality independently arose at least three times, in the two genera of ‘tree sloths’, Bradypus and Choloepus, and the silky anteater, Cyclopes. This specialized locomotor ecology is expectedly reflected by distinctive morpho-functi...
Preprint
Full-text available
Spectacular photoluminescence (PL) phenomena have been increasingly reported in various organisms from diverse ecosystems. However, the chemical basis of this PL remains poorly defined, and its potential ecological function is still blurry, especially in mammals. Here we used state-of-the-art spectroscopy and multispectral imaging techniques to doc...
Preprint
Full-text available
Spectacular photoluminescence (PL) phenomena have been increasingly reported in various organisms from diverse ecosystems. However, the chemical basis of this PL remains poorly defined, and its potential ecological function is still blurry, especially in mammals. Here we used state-of-the-art spectroscopy and multispectral imaging techniques to doc...
Preprint
Examples of photoluminescence (PL) are being reported with increasing frequency in a wide range of organisms from diverse ecosystems. However, the chemical basis of this PL remains poorly defined, and our understanding of its potential ecological function is still superficial. Amongst mammals, recent analyses have identified free-base porphyrins as...
Article
Full-text available
Background Mammals are a highly diverse group, with body mass ranging from 2 g to 170 t, and encompassing species with terrestrial, aquatic, aerial, and subterranean lifestyles. The skeleton is involved in most aspects of vertebrate life history, but while previous macroevolutionary analyses have shown that structural, phylogenetic, and functional...
Article
Full-text available
Long bones comprise articular ends (epiphyses) joined by transitional metaphyses and a diaphysis (shaft). The structure of the latter is often viewed as regularly tubular across tetrapods (limbed vertebrates). However, assessments of the bone structure along the whole diaphysis are rare. Here I assess whole‐diaphysis profiles of global compactness...
Article
Full-text available
Convergent evolution is a major topic in evolutionary biology. Low bone cortical compactness (CC, a measure of porosity of cortical bone) in the extant genera of ‘tree sloths’, has been linked to their convergent slow arboreal ecology. This proposed relationship of low CC with a slow arboreal lifestyle suggests potential convergent evolution of thi...
Preprint
Lifestyle convergences and related phenotypes are a major topic in evolutionary biology. Low bone cortical compactness (CC), shared by the two genera of 'tree sloths', has been linked to their convergently evolved slow arboreal ecology. The proposed relationship of low CC with 'tree sloths' lifestyle suggests a potential convergent acquisition of t...
Conference Paper
The acquisition of a fossorial lifestyle in squamates provides an excellent framework to study convergent evolution. In that context, the gross morphology of the skull in these head-first-burrowers has been the subject of several studies. However, to our knowledge, the inner structure of the cranial bones has never been quantified. We here test whe...
Poster
The acquisition of a fossorial lifestyle in squamates provides an excellent framework to study convergent evolution. In that context, the gross morphology of the skull in these head-first-burrowers has been the subject of several studies. However, to our knowledge, the inner structure of the cranial bones has never been quantified. We here test whe...
Article
Full-text available
Mustelidae, a carnivoran clade that includes for instance weasels, badgers, otters and martens, has undergone several evolutionary transitions of lifestyle, resulting in specializations for fossorial, natatorial and scansorial locomotion, in addition to more generalized species. The family is therefore regarded as offering an adequate framework for...
Conference Paper
Fossoriality has been acquired repeatedly in the evolutionary history of squamates (e.g., worm lizards, sand skinks, hog-nosed snakes). Related to this case of convergent evolution, the gross morphology of the skull in the corresponding fossorial clades has been subject of numerous studies. Indeed, these clades mostly comprise head-first-burrowers,...
Presentation
In this PhD work, various levels of bone organization are studied for a comprehensive understanding of the traits related to convergent evolution of slow arboreal locomotion. Within mammals, this behavior was independently acquired in at least six phylogenetically and geographically distant lineages: the two genera of Central-South American tree sl...
Conference Paper
Vertebrate ecology has been successfully inferred from bone microstructure in the past, but a systematic approach to quantify differences of the inner bone structure in the skull of squamate reptiles, i.e., lizards and snakes, has never been undertaken. In head-first-burrowing squamates, for example, the cranium is the structure exposed to the grea...
Article
Full-text available
The lifestyle of extinct tetrapods is often difficult to assess when clear morphological adaptations such as swimming paddles are absent. According to the hypothesis of bone functional adaptation, the architecture of trabecular bone adapts sensitively to physiological loadings. Previous studies have already shown a clear relation between trabecular...
Article
Full-text available
Sciuromorph rodents are a monophyletic group comprising about 300 species with a body mass range spanning three orders of magnitude and various locomotor behaviors that we categorized into arboreal, fossorial and aerial. The purpose of this study was to investigate how the interplay of locomotor ecology and body mass affects the morphology of the s...
Article
Full-text available
Xenarthrans stand out among mammals for various reasons, one of them being their musculoskeletal postcranial specializations. Extant armadillos, anteaters, and sloths feature archetypical adaptations to digging and/or diverse arboreal lifestyles. Numerous extinct xenarthrans dramatically depart in size and morphology from their extant relatives, wh...
Article
Full-text available
In conventional geometric morphometric analyses of limb long bones, differences in the evolutionary capacity of articular surfaces and non-articular structures often remain unrecognised. It can be shown that areas of high spatial variance dominate shape data, which is problematic for the functional interpretation of limb long bone shape. We herein...
Article
Full-text available
The abundance of skeletal remains of cave bears in Pleistocene deposits can offer crucial information on the biology and life history of this megafaunal element. The histological study of 62 femora from 23 different European localities and comparisons with specimens of five extant ursid species revealed novel data on tissue types and growth pattern...
Data
List of investigated specimens (with their ontogenetic stage and locality) and related histomorphometrical measurements. (XLSX)
Data
Averaged inter-LAG distances by species or locality for U. spelaeus s.l. (XLSX)
Article
Full-text available
Bone remodeling, one of the main processes that regulate bone microstructure, consists of bone resorption followed by the deposition of secondary bone at the same location. Remodeling intensity varies among taxa, but a characteristically compact cortex is ubiquitous in the long bones of mature terrestrial mammals. A previous analysis found that cor...
Article
Full-text available
South America was isolated during most of the Cenozoic, and it was home to an endemic fauna. The South American Native Ungulates (SANUs) exhibited high taxonomical, morphological, and ecological diversity and were widely distributed on the continent. However, most SANU fossil records come from high latitudes. This sampling bias challenges the study...
Article
Full-text available
Background: Sloths are one of only two exceptions to the mammalian 'rule of seven' vertebrae in the neck. As a striking case of breaking the evolutionary constraint, the explanation for the exceptional number of cervical vertebrae in sloths is still under debate. Two diverging hypotheses, both ultimately linked to the low metabolic rate of sloths,...
Preprint
Full-text available
Trabecular architecture (i.e., the main orientation of the bone trabeculae, their relative number, mean thickness, spacing, etc.) has been shown experimentally to adapt with extreme accuracy and sensitivity to the loadings applied to the bone during life. However, the potential of trabecular parameters used as a proxy for the mechanical environment...
Article
Full-text available
The present 3D Dataset contains the 3D models analyzed in: Amson et al., Under review. Evolutionary Adaptation to Aquatic Lifestyle in Extinct Sloths Can Lead to Systemic Alteration of Bone Structure doi:10.1098/rspb.2018.0270.
Article
Full-text available
Longevity and other life history variables are key to understanding evolutionary processes and the biology of extinct animals. For the past 20 years, the lifespan of cave bears received an increased interest. Studies focusing on incremental lines of tooth cementum resulted in detailed mortality patterns from different localities. In this review, we...
Article
Full-text available
Background Bone structure has a crucial role in the functional adaptations that allow vertebrates to conduct their diverse lifestyles. Much has been documented regarding the diaphyseal structure of long bones of tetrapods. However, the architecture of trabecular bone, which is for instance found within the epiphyses of long bones, and which has bee...
Article
Full-text available
Thalassocnus is a sloth (Mammalia, Tardigrada) adapted to an aquatic lifestyle. It was first described in the Neogene deposits of the Pisco Formation of Peru, from where most of the specimens come. The genus is represented by five species that extend from the upper Miocene to the upper Pliocene, occupying successive stratigraphic levels. Morpho-fun...
Article
Full-text available
Background Discovered on the southern margin of the North Sea Basin, “Phoca” vitulinoides represents one of the best-known extinct species of Phocidae. However, little attention has been given to the species ever since its original 19th century description. Newly discovered material, including the most complete specimen of fossil Phocidae from the...
Data
Phylogenetic matrix including Praepusa magyaricus and Praepusa pannonica.
Data
Supplemental Information to the reappraisal of Nanophoca vitulinoides.
Article
Full-text available
Abstract There are significant geographic gaps in our knowledge of marine mammal evolution because most fossils have been found and described from Northern Hemisphere localities and a few other high-latitude areas in the Southern Hemisphere. Here, we describe fossil cetacean remains from five geological units in the South American tropics (Urumaco,...
Article
Full-text available
Almost all mammals have seven vertebrae in their cervical spines. This consistency represents one of the most prominent examples of morphological stasis in vertebrae evolution. Hence, the requirements associated with evolutionary modifications of neck length have to be met with a fixed number of vertebrae. It has not been clear whether body size in...
Article
The orientation of the semicircular canals of the inner ear in the skull of vertebrates is one of the determinants of the capacity of this system to detect a given rotational movement of the head. Past functional studies on the spatial orientation of the semicircular canals essentially focused on the lateral semicircular canal (LSC), which is suppo...
Article
Full-text available
R package v.3.0. https://CRAN.R-project.org/package=Directional . A collection of functions for directional data analysis. Hypothesis testing, discriminant and regression analysis, MLE of distributions and more are included. The standard textbook for such data is the "Directional Statistics" by Mardia, K. V. and Jupp, P. E. (2000).
Article
Full-text available
During the mid-19th century, the German naturalist Hermann Karsten conducted a 12-year exploration (1844–1856) in the territories of Ecuador, New Granada (now Colombia) and Venezuela, allowing him to produce important botanic, geographic and geologic descriptions with valuable information that permits us to refer to him as a pioneer in many of thes...
Article
Full-text available
How skeletal elements scale to size is a fundamental question in biology. While the external shape of long bones was intensively studied, an important component of their organization is also found in their less accessible inner structure. Here, we studied mid-diaphyseal properties of limb long bones, characterizing notably the thickness of their co...
Article
Full-text available
How skeletal elements scale to size is a fundamental question in biology. While the external shape of long bones was intensively studied, an important component of their organization is also found in their less accessible inner structure. Here, we studied mid-diaphyseal properties of limb long bones, characterizing notably the thickness of their c...
Article
Full-text available
The Huayquerías Formation (late Miocene, Huayquerian SALMA) is broadly exposed in west-central Argentina (Mendoza). The target of several major paleontological expeditions in the first half of the 20th century, the Mendozan Huayquerías ("badlands") have recently yielded a significant number of new fossil finds. In this contribution we describe a co...