scholarly journals Testing Equid Body Mass Estimate Equations on Modern Zebras—With Implications to Understanding the Relationship of Body Size, Diet, and Habitats of Equus in the Pleistocene of Europe

2021 ◽  
Vol 9 ◽  
Author(s):  
Juha Saarinen ◽  
Omar Cirilli ◽  
Flavia Strani ◽  
Keiko Meshida ◽  
Raymond L. Bernor

The monodactyl horses of the genus Equus originated in North America during the Pliocene, and from the beginning of the Pleistocene, they have been an essential part of the large ungulate communities of Europe, North America and Africa. Understanding how body size of Equus species evolved and varied in relation to changes in environments and diet thus forms an important part of understanding the dynamics of ungulate body size variation in relation to Pleistocene paleoenvironmental changes. Here we test previously published body mass estimation equations for the family Equidae by investigating how accurately different skeletal and dental measurements estimate the mean body mass (and body mass range) reported for extant Grevy's zebra (Equus grevyi) and Burchell's zebra (Equus quagga). Based on these tests and information on how frequently skeletal elements occur in the fossil record, we construct a hierarchy of best practices for the selection of body mass estimation equations in Equus. As a case study, we explore body size variation in Pleistocene European Equus paleopopulations in relation to diet and vegetation structure in their paleoenvironments. We show a relationship between diet and body size in Equus: very large-sized species tend to have more browse-dominated diets than small and medium-sized species, and paleovegetation proxies indicate on average more open and grass-rich paleoenvironments for small-sized, grazing species of Equus. When more than one species of Equus co-occur sympatrically, the larger species tend to be less abundant and have more browse-dominated diets than the smaller species. We suggest that body size variation in Pleistocene Equus was driven by a combined effect of resource quality and availability, partitioning of habitats and resources between species, and the effect of environmental openness and group size on the body size of individuals.

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260505
Author(s):  
Jessica Mongillo ◽  
Giulia Vescovo ◽  
Barbara Bramanti

Over the centuries, iconographic representations of St Anthony of Padua, one of the most revered saints in the Catholic world, have been inspired by literary sources, which described the Saint as either naturally corpulent or with a swollen abdomen due to dropsy (i.e. fluid accumulation in the body cavities). Even recent attempts to reconstruct the face of the Saint have yielded discordant results regarding his outward appearance. To address questions about the real appearance of St Anthony, we applied body mass estimation equations to the osteometric measurements taken in 1981, during the public recognition of the Saint’s skeletal remains. Both the biomechanical and the morphometric approach were employed to solve some intrinsic limitations in the equations for body mass estimation from skeletal remains. The estimated body mass was used to assess the physique of the Saint with the body mass index. The outcomes of this investigation reveal interesting information about the body type of the Saint throughout his lifetime.


Author(s):  
Erik Trinkaus ◽  
Alexandra P. Buzhilova ◽  
Maria B. Mednikova ◽  
Maria V. Dobrovolskaya

Considerations of the body proportions and estimates of body mass and stature of the Sunghir people provide a general baseline for the assessment of a variety of aspects of their paleobiology. They also furnish some indications by themselves. Some of these aspects have been men­tioned with respect to sexual assessment of the adult remains (especially Sunghir 1 and 4; chapter 6), and methodological considerations have been addressed in part in chapter 5. What is presented here is a more detailed assessment of size in terms of body mass estimation and stature, and considerations of body proportions to the extent that they can be evaluated for Sunghir 1, 2 and 3. Body mass estimation was discussed in chapter 5, and it is done here exclusively using the dimension of the weight-bearing femoral articulations and/or metaphyses. It provides insights into trends in overall body size and health, but it is also central to the appropriate scaling of other aspects of morphology, from limb length and strength to brain size. Since the early comments of Boule (1911–1913) and Coon (1962), there has been a series of attempts to evaluate the body proportions (principally using limb segment lengths but also body breadth and trunk length) of Pleistocene humans as indications of both ecogeographical patterning among Late Pleistocene humans and possible reflections of their population dynamics (e.g., Trinkaus 1981, 2007; Walker and Leakey 1993; Ruff 1994; Holliday 1997a, 1997b, 2000, 2006a; Trinkaus and Zilhão 2002; Frelat 2007). The critical problem in assessing body proportions is to determine the independent variable. This must be done a priori, based on biological considerations. Stature estimation presents a variety of difficulties among Late Pleistocene humans, given variation in linear body proportions, but it can provide an indication of overall health, especially given the trends evident through the European Upper Paleolithic (Formicola and Giannecchini 1999; Holt and Formicola 2008). Assessments of body proportions depend in part on body mass estimation, and stature predictions depend on body proportions.


2016 ◽  
Vol 22 ◽  
pp. 133-156 ◽  
Author(s):  
Charlotte A. Brassey

AbstractBody mass is a key parameter for understanding the physiology, biomechanics, and ecology of an organism. Within paleontology, body mass is a fundamental prerequisite for many studies considering body-size evolution, survivorship patterns, and the occurrence of dwarfism and gigantism. The conventional method for estimating fossil body mass relies on allometric scaling relationships derived from skeletal metrics of extant taxa, but the recent application of three-dimensional imaging techniques to paleontology (e.g., surface laser scanning, computed tomography, and photogrammetry) has allowed for the rapid digitization of fossil specimens. Volumetric body-mass estimation methods based on whole articulated skeletons are therefore becoming increasingly popular. Volume-based approaches offer several advantages, including the ability to reconstruct body-mass distribution around the body, and their relative insensitivity to particularly robust or gracile elements, i.e., the so-called ‘one bone effect.’ Yet their application to the fossil record will always be limited by the paucity of well-preserved specimens. Furthermore, uncertainties with regards to skeletal articulation, body density, and soft-tissue distribution must be acknowledged and their effects quantified. Future work should focus on extant taxa to improve our understanding of body composition and increase confidence in volumetric model input parameters.


2011 ◽  
Vol 59 (4) ◽  
pp. 201 ◽  
Author(s):  
Elise Furlan ◽  
J. Griffiths ◽  
N. Gust ◽  
R. Armistead ◽  
P. Mitrovski ◽  
...  

The body size of the platypus (Ornithorhynchus anatinus) is known to vary across both its latitudinal range and relatively short geographic distances. Here we consider how variation in platypus length and weight associates with environmental variables throughout the species’ range. Based on data from over 800 individuals, a Bergmann’s cline (increased body size in regions of lower temperature) was detected across the species latitudinal range. The opposite association, however, was present at smaller scales when comparing platypus body size and temperature within southern mainland Australia, or within an individual river basin. Temperature regimes alone clearly did not dictate body size in platypuses, although disentangling the effects of different climatic variables on body size variation was difficult because of correlations amongst variables. Nevertheless, within suitable platypus habitat in south-eastern Australia, areas of relatively lower rainfall and higher temperatures were typically associated with larger-bodied platypuses. The potential benefits to larger-bodied animals living under these conditions are explored, including consideration of variation in energy expenditure and food availability. Assuming these associations with environmental variables are biologically significant, a shift in platypus body size is anticipated in the future with predicted changes in climate.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Cheng Guo ◽  
Shuai Gao ◽  
Ali Krzton ◽  
Long Zhang

Abstract Background Two previous studies on interspecific body size variation of anurans found that the key drivers of variation are the species’ lifestyles and the environments that they live in. To examine whether those findings apply at the intraspecific level, we conducted a study of the Asian common toad (Duttaphrynus melanostictus), a terrestrial anuran distributed in tropical regions. The body size of toads from 15 locations, covering the majority of their geographic range, and local environmental data were summarized from published literature. We used a model selection process based on an information-theoretic approach to examine the relationship between toad body size and those environmental parameters. Results We found a positive correlation between the body size of the Asian common toad and the water deficit gradient, but no linkage between body size and temperature-related parameters. Furthermore, there was a positive correlation between the seasonality of precipitation and body size of females from different sampled populations. Conclusions As a terrestrial anuran, the Asian common toad should experience greater pressure from environmental fluctuations than aquatic species. It is mainly distributed in tropical regions where temperatures are generally warm and stable, but water availability fluctuates. Therefore, while thermal gradients are not strong enough to generate selection pressure on body size, the moisture gradient is strong enough to select for larger size in both males and females in dryer regions. Larger body size supports more efficient water conservation, a pattern in accordance with the prediction that lifestyles of different species and their local habitats determine the relationship between body size and environment. In addition, larger females occur in regions with greater seasonality in precipitation, which may happen because larger females can afford greater reproductive output in a limited reproductive season.


2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Go‐Un Jung ◽  
U‐Young Lee ◽  
Dong‐Ho Kim ◽  
Dai‐Soon Kwak ◽  
Yong‐Woo Ahn ◽  
...  

2019 ◽  
Vol 46 (4) ◽  
pp. 334
Author(s):  
Tad M. Bartareau

Context Measuring a mammal’s body mass has importance in understanding nutritional condition, reproductive biology and ecology. It can be impractical for a researcher to measure the body mass when equipment needed to weigh individuals is inadequate or unavailable. Aims The purpose of this study was to develop a model to accurately estimate the body mass of hunter-harvested Florida white-tailed deer (Odocoileus virginianus osceola, Odocoileus virginianus seminolus) based on the relationship between scale mass, sex and standard age and morphometric measurement predictor variables easily obtainable in the field. Methods An information-theoretic approach was used to evaluate simple and multiple linear regression models with 67% of the data, and the best model in the set was validated using the remaining 33%. Key results Chest girth was the best single predictor of body mass. A global model including sex, age, age2 and body length variables was better supported than chest girth alone, and subspecies information did not contribute significantly to the body-mass–predictor-variable relationship. The best model explained 98.5% of the variation in body mass as follows: body mass (kg) = –18.41 + 6.53 × sex (0 = female, 1 = male) + 5.04 × age (year) – 0.49 × age2 (year2) + 4.76 × 10−3 × chest girth2 (cm2) + 0.12 × body length (cm). The 95% confidence interval on the bias of the estimated body mass of the best model was –0.50 to 0.59 kg. The difference between estimated and scale body mass was –0.04 kg ± 0.28 (s.e.). Conclusions Individuals maintained a similar proportion of body mass to predictor variables, and differences between the observed and estimated body mass of model applied to the validation dataset were not significant. Implications The validated body-mass-estimation model presented will enable accurate estimates of the body mass of white-tailed deer in cases where standard age and morphometric measurements are available, but the individuals were not weighed. These results provide a basis to formulate and parameterise body-mass-estimation models for other white-tailed deer subspecies and populations. Without the need for specialised equipment, the body-mass-estimation model can be used by personnel involved in white-tailed deer research, management and sport hunting to assess trends in individual and population health in support of this species’ conservation. Photograph by Carlton Ward Jr.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kyle Atkins-Weltman ◽  
Eric Snively ◽  
Patrick O'Connor

The ability to accurately and reliably estimate body mass of extinct taxa is a vital tool for interpreting the physiology and even behavior of long-dead animals. For this reason, paleontologists have developed many possible methods of estimating the body mass of extinct animals, with varying degrees of success. These methods can be divided into two main categories: volumetric mass estimation and extant scaling methods. Each has advantages and disadvantages, which is why, when possible, it is best to perform both, and compare the results to determine what is most plausible within reason. Here we employ volumetric mass estimation (VME) to calculate an approximate body mass for previously described specimens of Anzu wyliei from the Carnegie Museum of Natural History. We also use extant scaling methods to try to obtain a reliable mass estimate for this taxon.  In addition, we present the first digital life restoration and convex hull of the dinosaur Anzu wyliei used for mass estimation purposes. We found that the volumetric mass estimation using our  digital model was 216-280kg, which falls within the range predicted by extant scaling techniques, while the mass estimate using minimum convex hulls was below the predicted range, between 159-199 kg . The VME method for Anzu wyliei strongly affirms the predictive utility of extant-based scaling. However, volumetric mass estimates are likely more precise because the models are based on comprehensive specimen anatomy rather than regressions of a phylogenetically comprehensive but disparate sample.


Paleobiology ◽  
2001 ◽  
Vol 27 (4) ◽  
pp. 735-750 ◽  
Author(s):  
Ryosuke Motani

In computational studies of the body mass and surface area of vertebrates, it is customary to assume that body cross-sections are approximately elliptical. However, a review of actual vertebrate cross-sections establishes that this assumption is not usually met. A new cross-sectional model using superellipses is therefore introduced, together with a scheme that allows estimates to be given with ranges. Tests of the new method, using geometrical shapes, miniature vertebrate models, and actual animals, show that the method has a high accuracy in body mass estimation. A new computer program to perform the computation is introduced. The application of the method to some Mesozoic marine reptiles suggests that the tuna-shaped ichthyosaur Stenopterygius probably had body masses comparable to those of average cetaceans of the same body length.


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