Evolution of body mass in the Pan-Alcidae (Aves, Charadriiformes): the effects of combining neontological and paleontological data

Paleobiology ◽  
2015 ◽  
Vol 42 (1) ◽  
pp. 8-26 ◽  
Author(s):  
N. Adam Smith
Keyword(s):  
Body Mass ◽  
Mass Range ◽  
Extinct Species ◽  
Paleontological Data ◽  
Ideal Candidate ◽  
Extant Species ◽  
Size Evolution ◽  
Body Size Evolution ◽  
Phylogenetic Hypotheses ◽  
Maximum Body

AbstractHypotheses regarding the evolution of many clades are often generated in the absence of data from the fossil record and potential biases introduced by exclusion of paleontological data are frequently ignored. With regard to body size evolution, extinct taxa are frequently excluded because of the lack of body mass estimates—making identification of reliable clade specific body mass estimators crucial to evaluating trends on paleontological timescales. Herein, I identify optimal osteological dimensions for estimating body mass in extinct species of Pan-Alcidae (Aves, Charadriiformes) and utilize newly generated estimates of body mass to demonstrate that the combination of neontological and paleontological data produces results that conflict with hypotheses generated when extant species data are analyzed in isolation. The wing-propelled diving Pan-Alcidae are an ideal candidate for comparing estimates of body mass evolution based only on extant taxa with estimates generated including fossils because extinct species diversity (≥31 species) exceeds extant diversity, includes examples from every extant genera, and because phylogenetic hypotheses of pan-alcid relationships are not restricted to the 23 extant species. Phylogenetically contextualized estimation of body mass values for extinct pan-alcids facilitated evaluation of broad scale trends in the evolution of pan-alcid body mass and generated new data bearing on the maximum body mass threshold for aerial flight in wing-propelled divers. The range of body mass in Pan-Alcidae is found to exceed that of all other clades of Charadriiformes (shorebirds and allies) and intraclade body mass variability is recognized as a recurring theme in the evolution of the clade. Finally, comparisons of pan-alcid body mass range with penguins and the extinct †Plotopteridae elucidate potentially shared constraints among phylogenetically disparate yet ecologically similar clades of wing-propelled divers.

scholarly journals Effects of allometry, productivity and lifestyle on rates and limits of body size evolution

2013 ◽  
Vol 280 (1764) ◽  
pp. 20131007 ◽  
Author(s):  
Jordan G. Okie ◽  
Alison G. Boyer ◽  
James H. Brown ◽  
Daniel P. Costa ◽  
S. K. Morgan Ernest ◽  
...  
Keyword(s):  
Body Size ◽  
Generation Time ◽  
Allometric Scaling ◽  
Empirical Work ◽  
Morphological Diversity ◽  
Maximum Size ◽  
Scaling Exponent ◽  
Size Evolution ◽  
Body Size Evolution ◽  
Maximum Body

Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow–fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow–fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity.

scholarly journals Fossils and living taxa agree on patterns of body mass evolution: a case study with Afrotheria

2015 ◽  
Vol 282 (1821) ◽  
pp. 20152023 ◽  
Author(s):  
Mark N. Puttick ◽  
Gavin H. Thomas
Keyword(s):  
Body Mass ◽  
Fossil Record ◽  
Morphological Character ◽  
Morphological Evolution ◽  
Evolutionary Model ◽  
The Body ◽  
Evolutionary Patterns ◽  
Size Evolution ◽  
Body Size Evolution

Most of life is extinct, so incorporating some fossil evidence into analyses of macroevolution is typically seen as necessary to understand the diversification of life and patterns of morphological evolution. Here we test the effects of inclusion of fossils in a study of the body size evolution of afrotherian mammals, a clade that includes the elephants, sea cows and elephant shrews. We find that the inclusion of fossil tips has little impact on analyses of body mass evolution; from a small ancestral size (approx. 100 g), there is a shift in rate and an increase in mass leading to the larger-bodied Paenungulata and Tubulidentata, regardless of whether fossils are included or excluded from analyses. For Afrotheria, the inclusion of fossils and morphological character data affect phylogenetic topology, but these differences have little impact upon patterns of body mass evolution and these body mass evolutionary patterns are consistent with the fossil record. The largest differences between our analyses result from the evolutionary model, not the addition of fossils. For some clades, extant-only analyses may be reliable to reconstruct body mass evolution, but the addition of fossils and careful model selection is likely to increase confidence and accuracy of reconstructed macroevolutionary patterns.

Hierarchy and the reconstruction of evolutionary trends: evidence for constraints on the evolution of body size in terrestrial caniform carnivorans (Mammalia)

Paleobiology ◽  
2008 ◽  
Vol 34 (4) ◽  
pp. 553-562 ◽  
Author(s):  
John A. Finarelli
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Small Body ◽  
Information Criterion ◽  
Size Increase ◽  
Size Evolution ◽  
Species Pairs ◽  
Body Sizes ◽  
Intermediate Size ◽  
Body Size Evolution

Body mass is an important organism-level variable in mammalian biology, correlated with physiology, life history, and ecology. To analyze the dynamics of body size evolution, increases and decreases in body mass were tallied for ancestor-descendant (AD) species pairs for 519 terrestrial caniform taxa. To account for uncertainty phylogeny, a bootstrapping routine shuffled hypothesized AD pairs, and average proportions of increases were binned as a function of ancestral body mass. A set of models relating the rate of body size increase were evaluated with the Akaike Information Criterion (AIC). AIC selected three models of the candidate set as equivalent in support by the observed body mass data. These three models propose body size increase for small AD pairs and body size decrease for large AD pairs, although they differ in their treatment of taxa at intermediate sizes.These results demonstrate the presence of constraints bounding the caniform distribution at large and small body sizes, stabilizing the distribution through time, which stands in contrast to a broader mammalian pattern. At a finer phylogenetic scale, subclades within intermediate size classes display proportions that are significantly different from unbiased, with several clades previously cited as examples of “Cope's Rule” showing biased increases in size, and basal mustelids (badgers, and allied genera), Mephitidae (skunks), and Vulpini (“foxes”) exhibiting biased decreases. The caniform pattern is therefore the result of superimposed, clade-specific trajectories, demonstrating that the inferred dynamics of body size evolution and even the direction of trends in body size evolution within the Caniformia, and for mammals in general, depend on the hierarchical scale of the analysis.

scholarly journals Accelerated body size evolution during cold climatic periods in the Cenozoic

2017 ◽  
Vol 114 (16) ◽  
pp. 4183-4188 ◽  
Author(s):  
Julien Clavel ◽  
Hélène Morlon
Keyword(s):  
Body Size ◽  
Biotic Interactions ◽  
Morphological Diversity ◽  
Evolutionary Rates ◽  
Phenotypic Evolution ◽  
Geological Time ◽  
Radiation Theory ◽  
Extant Species ◽  
Size Evolution ◽  
Body Size Evolution

How ecological and morphological diversity accumulates over geological time is much debated. Adaptive radiation theory has been successful in testing the effects of biotic interactions on the rapid divergence of phenotypes within a clade, but this theory ignores abiotic effects. The role of abiotic drivers on the tempo of phenotypic evolution has been tested only in a few lineages or small clades from the fossil record. Here, we develop a phylogenetic comparative framework for testing if and how clade-wide rates of phenotypic evolution vary with abiotic drivers. We apply this approach to comprehensive bird and mammal phylogenies, body size data for 9,465 extant species, and global average temperature trends over the Cenozoic. Across birds and mammals, we find that the rate of body size evolution is primarily driven by past climate. Unexpectedly, evolutionary rates are inferred to be higher during periods of cold rather than warm climates in most groups, suggesting that temperature influences evolutionary rates by modifying selective pressures rather than through its effect on energy availability and metabolism. The effect of climate on the rate of body size evolution seems to be a general feature of endotherm evolution, regardless of wide differences in species’ ecology and evolutionary history. These results suggest that climatic changes played a major role in shaping species’ evolution in the past and could also play a major role in shaping their evolution in the future.

scholarly journals Modeling body size evolution in Felidae under alternative phylogenetic hypotheses

2009 ◽  
Vol 32 (1) ◽  
pp. 170-176 ◽  
Author(s):  
José Alexandre Felizola Diniz-Filho ◽  
João Carlos Nabout
Keyword(s):  
Body Size ◽  
Size Evolution ◽  
Body Size Evolution ◽  
Phylogenetic Hypotheses

scholarly journals New insights into the genetic mechanisms of body size evolution in Carnivora

2020 ◽  
Author(s):  
Xin Huang ◽  
Di Sun ◽  
Tianzhen Wu ◽  
Xing Liu ◽  
Shixia Xu ◽  
...  
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Rapid Evolution ◽  
Large Body ◽  
The Body ◽  
Molecular Evidence ◽  
Size Evolution ◽  
Body Size Evolution

Abstract Background The range of body sizes in Carnivora is unparalleled in any other mammalian order, with more than 130,000 times in body mass and 50 times in length. However, the molecular mechanisms underlying the huge difference in body size of Carnivora have not been explored so far. Results Herein, we performed a comparative genomics analysis of 20 carnivores to explore the genetic basis of great body size variation in carnivores. Phylogenetic generalized least squares (PGLS) revealed that 337 genes were significantly related to both head body length and body mass, these genes were defined as body size associated genes (BSAGs). Fourteen positively related BSAGs were found to be associated with obesity and three of which were identified to be under rapid evolution in the extremely large body-sized carnivores, which suggested that these obesity-related BSAGs might have driven the body size expansion in carnivores. Interestingly, 100 BSAGs were examined to be associated with cancer control in carnivores, particularly 15 cancer-related genes were found to be under rapid evolution in extremely large carnivores. These results strongly suggested that large body-sized carnivores might have evolved effective mechanism to resist cancer, which could be regarded as molecular evidence to support for the Peto’s paradox. For small carnivores, we identified 15 rapidly evolving genes and found six genes with fixed amino acid changes that were reported to reduce body size. Conclusion This study brings new insights into the molecular mechanisms that drove the diversifying evolution of body size in carnivores, and provides new target genes for exploring the mysteries of body size evolution in mammals.

Oligo-Miocene climate change and mammal body-size evolution in the northwest United States: a test of Bergmann's Rule

Paleobiology ◽  
10.1666/13006 ◽  
2013 ◽  
Vol 39 (4) ◽  
pp. 648-661 ◽  
Author(s):  
John D. Orcutt ◽  
Samantha S. B. Hopkins
Keyword(s):  
United States ◽  
Body Size ◽  
Body Mass ◽  
Global Climate ◽  
Climatic Conditions ◽  
Bergmann’S Rule ◽  
Bergmann's Rule ◽  
Complex Interactions ◽  
Size Evolution ◽  
Body Size Evolution

Whether or not climate plays a causal role in mammal body-size evolution is one of the longest-standing debates in ecology. Bergmann's Rule, the longest-standing modeladdressing this topic, posits that geographic body-mass patterns are driven by temperature, whereas subsequent research has suggested that other ecological variables, particularly precipitation and seasonality, may be the major drivers of body-size evolution. While paleoecological data provide a unique and crucial perspective on this debate, paleontological tests of Bergmann's rule and its corollaries have been scarce. We present a study of body-size evolution in three ecologically distinct families of mammal (equids, canids, and sciurids) during the Oligo-Miocene of the northwest United States, an ideal natural laboratory for such studies because of its rich fossil and paleoclimatic records. Body-size trends are different in all three groups, and in no case is a significant relationship observed between body size and any climatic variable, counter to what has been observed in modern ecosystems. We suggest that for most of the Cenozoic, at least in the Northwest, body mass has not been driven by any one climatic factor but instead has been the product of complex interactions between organisms and their environments, though the nature of these interactions varies from taxon to taxon. The relationship that exists between climate and body size in many groups of modern mammals, therefore, is the exception to the rule and may be the product of an exceptionally cool and volatile global climate. As anthropogenic global warming continues and ushers in climatic conditions more comparable to earlier intervals of the Cenozoic than to the modern day, models of corresponding biotic variables such as body size may lose predictive power if they do not incorporate paleoecological data.

scholarly journals Rise of the titans: baleen whales became giants earlier than thought

2019 ◽  
Vol 15 (5) ◽  
pp. 20190175 ◽  
Author(s):  
Giovanni Bianucci ◽  
Felix G. Marx ◽  
Alberto Collareta ◽  
Agata Di Stefano ◽  
Walter Landini ◽  
...  
Keyword(s):  
Feeding Strategy ◽  
Early Pleistocene ◽  
Additional Material ◽  
Baleen Whales ◽  
Mode Shift ◽  
Extant Species ◽  
Size Evolution ◽  
Body Size Evolution ◽  
Long Term Impact

Baleen whales (Mysticeti) are major ecosystem engineers, thanks to their enormous size and bulk filter feeding strategy. Their signature gigantism is thought to be a relatively recent phenomenon, resulting from a Plio-Pleistocene mode shift in their body size evolution. Here, we report the largest whale fossil ever described: an Early Pleistocene (1.5–1.25 Ma) blue whale from Italy with an estimated body length of up to 26 m. Macroevolutionary modelling taking into account this specimen, as well as additional material from the Miocene of Peru, reveals that the proposed mode shift occurred either somewhat earlier, or perhaps not at all. Large-sized mysticetes comparable to most extant species have existed since at least the Late Miocene, suggesting a long-term impact on global marine ecosystems.

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