Papers by Marcelo Sánchez-Villagra
The growing interest and major advances of the last decades in evolutionary developmental biology... more The growing interest and major advances of the last decades in evolutionary developmental biology (Evo-Devo) have led to the recognition of the incompleteness of the Modern Synthesis of evolutionary theory. Here we discuss how paleontology makes significant contributions to integrate evolution and development. First, extinct organisms often inform us about developmental processes by showing a combination of features unrecorded in living species. We illustrate this point using the vertebrate fossil record and studies relating bone ossification to life history traits. Second, we discuss exceptionally preserved fossils that document rare ontogenetic sequences and illustrate this case with the patterns of heterochrony observed in Cambrian crustacean larvae preserved three-dimensionally. Third, most fossils potentially document the evolutionary patterns of allometry and modularity, as well as some of the (paleo)ecological factors that had influenced them. The temporal persistence of adaptive patterns in rodent evolution serves to address the importance of ecological constraints in evolution. Fourth, we discuss how the macroevolutionary patterns observed in the tetrapod limb, in the mammal molar proportions, and in the molluscan shell provide independent tests of the validity of morphogenetic models proposed on living species. Reciprocally, these macroevolutionary patterns often act as a source of inspiration to investigate the underlying rules of development, because, at the end, they are the patterns that the neo-Darwinian theory was unable to account for.
Journal of Vertebrate Paleontology, 1997
Page 1. Journal of Vertebrate Paleontology 17(4):717-724, December 1997 © 1997 by the Society of ... more Page 1. Journal of Vertebrate Paleontology 17(4):717-724, December 1997 © 1997 by the Society of Vertebrate Paleontology A SKULL OF PROARGYROlAGUS, THE OLDEST ARGYROLAGID (LATE OLIGOCENE SALLA BEDS ...
Osteological and skeletal characters have long been proven to be particularly informative in taxo... more Osteological and skeletal characters have long been proven to be particularly informative in taxonomic and systematic research. Furthermore, ossification sequences are assumed to be a potential tool to investigate developmental states and developmental modes of fossil and extant skeletal specimens. Herein, we provide a detailed account on adult osteology and skeletogenesis in the Montevideo treefrog, Hypsiboas pulchellus (Anura: Hylidae) based on evaluation of a series of cleared and stained specimens. A consensus sequence of ossification, i.e., the order of appearance of mineralized elements until early metamorphosis could be determined as (parasphenoid, presacral vertebrae I-VII, frontoparietal, exoccipital) – transverse processes of presacral vertebrae I-VIII – sacral vertebra – (humerus, radioulna, ilium, femur, tibiofibula, scapula) – (cleithrum, clavicle, coracoids, metacarpals, tarsals, metatarsals, phalanges, hypochord) – (prootic, angulosplenial, dentary, maxilla, premaxill...
List of new and modified characters and scoring changes. (PDF 46 kb)
Across the globe and at different times in the past millennia, the evolutionary history of domest... more Across the globe and at different times in the past millennia, the evolutionary history of domesticated animals has been greatly affected by the myriad, complex, and diverse interactions humans have had with the animals closest to them. This book presents a broad synthesis of this subject, from the rich biology behind the initial stages of domestication to how the creation of breeds reflects cultural and societal transformations that have impacted the biosphere. The book draws from a wide range of fields, including evolutionary biology, zooarchaeology, ethnology, genetics, developmental biology, and evolutionary morphology to provide a fresh perspective to this classic topic. Relying on various conceptual and technical tools, it examines the natural history of phenotypes and their developmental origins. The book presents case studies involving mammals, birds, fish, and insect species, and it highlights the importance of domestication for the comprehension of evolution, anatomy, ontogeny, and dozens of fundamental biological processes. Bringing together the most current developments, the book will interest a wide range of readers, from evolutionary biologists, developmental biologists, and geneticists to anthropologists and archaeologists.
Embryos in Deep Time, 2019
The sequence of dental eruption is diverse in non-random ways across mammalian species and phylog... more The sequence of dental eruption is diverse in non-random ways across mammalian species and phylogenetic patterns and life history correlates can be found. For example, the shifting of the time of eruption of replacement teeth in primates has been suggested as indicative of life span and speed of growth. The tendency to replace teeth early in species with fast growth and long life span is called the Schultz’s ‘rule’. In order to explore this hypothesis for another mammalian clade, we provide new dental eruption data for extant and extinct cervids and integrate these into a survey for the Artiodactyla. Examination in a phylogenetic context is of paramount importance to test for any life history correlations. The small sized Capreolus capreolus starts replacing the deciduous dentition after the second molar has emerged whereas the bigger sized cervid species such as Dama dama usually replace the first deciduous tooth already before this event. Additionally to the study of the tooth eru...
Swiss Journal of Palaeontology, 2014
Analyzing and interpreting life history data (e.g., aging and longevity, age at sexual maturity) ... more Analyzing and interpreting life history data (e.g., aging and longevity, age at sexual maturity) are fundamental in many paleontological studies. In the case of extant and fossil fishes, otoliths, and to a lesser degree other incrementally growing hard tissue structures such as scales and bones, have been utilized to reveal these data. We investigated the microanatomy and internal microstructure of opercula of Saurichthys, one of the most easily recognized and globally distributed fishes in the Triassic, to elucidate whether these prominent skull bones provide reliable age estimates. Opercula, and where the subopercula is present, of several outgroup taxa were sectioned to provide a phylogenetic framework for the study. The external protrusions and ridges or internal concentric bands or wrinkles are not related to internal age-related bone tissue structures such as annuli and growth zones, but are instead purely ornamental in the case of the former and probably structural/taphonomic in case of the latter. Opercular morphogenesis of Saurichthys opercula differs from that of the extant outgroups examined in that they show rostro-medial to caudo-lateral extending growth increments instead of ones that extend sub-parallel to the opercular bone surfaces. Individual age data could thus not be reliably extracted from those opercula. Furthermore, an odontode-like complex was not encountered in Saurichthys opercula, but a few specimens show a peculiar, weakly birefringent thin tissue layer of unknown origin filling the valleys between the external ornamental ridges. Although all Saurichthys opercula showed growth marks, these could not be counted to produce reliable individual age data, whereas bones with a more concentric cross section, such as the ceratohyal, appear better suited for this purpose.
Journal of Vertebrate Paleontology, 2013
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2010
Morphological and molecular data yield incongruent hypotheses concerning the interrelationships o... more Morphological and molecular data yield incongruent hypotheses concerning the interrelationships of chelid side-necked turtles, neither of which is widely accepted. Molecular studies recognize monophyletic South American and Australasian clades, whereas morphological characters distinguish a long-necked clade and a short-necked clade. We take a developmental approach to exploring chelid interrelationships. None of the nine species studied have the same growth pattern for all measurements examined, indicating changes in ontogenetic scaling of cranial characters was common during chelid evolution. The variability in scaling relationships precludes overwhelming support for either hypothesis. Scaling patterns are most similar between the geographically separate clades promoted by molecular analyses, and hence our data favor an independent origin of the long neck in South American and Australasian species. A close relationship between Hydromedusa and Chelus, rather than Chelodina, is supported by scaling patterns associated with a relative widening of the cranium. Our study exemplifies the utility of comparative ontogenetic trajectory data to test phylogenetic hypotheses.
Journal of Anatomy, 2012
Studies of evolutionary developmental biology commonly use 'model organisms' such as fruit flies ... more Studies of evolutionary developmental biology commonly use 'model organisms' such as fruit flies or mice, and questions are often functional or epigenetic. Phylogenetic investigations, in contrast, typically use species that are less common and mostly deal with broad scale analyses in the tree of life. However, important evolutionary transformations have taken place at all taxonomic levels, resulting in such diverse forms as elephants and shrews. To understand the mechanisms underlying morphological diversification, broader sampling and comparative approaches are paramount. Using a simple, standardized protocol, we describe for the first time the development of soft tissues and some parts of the skeleton, using lCT-imaging of developmental series of Echinops telfairi and Tenrec ecaudatus, two tenrecid afrotherian mammals. The developmental timing of soft tissue and skeletal characters described for the tenrecids is briefly compared with that of other mammals, including mouse, echidna, and the opossum. We found relatively few heterochronic differences in development in the armadillo vs. tenrec, consistent with a close relationship of Xenarthra and Afrotheria. Ossification in T. ecaudatus continues well into the second half of overall gestation, resembling the pattern seen in other small mammals and differing markedly from the advanced state of ossification evident early in the gestation of elephants, sheep, and humans.
Journal of Mammalian Evolution, 2012
Placental mammals occupy a larger morphospace and are taxonomically more diverse than marsupials ... more Placental mammals occupy a larger morphospace and are taxonomically more diverse than marsupials by an order of magnitude, as shown by quantitative and phylogenetic studies of several character complexes and clades. Many have suggested that life history acts as a constraint on the evolution of marsupial morphology. However, the frequent circumvention of constraints suggests that the pattern of morphospace occupation in marsupials is more a reflection of lack of ecological opportunity than one of biases in the production of variants during development. Features of marsupial physiology are a potential source of biases in the evolution of the group; these could be coupled with past macroevolutionary patterns that followed conditions imposed by global temperature changes. This is evident at the K/Pg boundary and at the Eocene/Oligocene boundary. The geographic pattern of taxonomic and morphological diversity in placental clades mirrors that of extant placentals as a whole versus marsupials: placentals of northern origin are more diverse those of southern one and include the clades that are outliers in taxonomic (rodents and bats) and ecomorphological (whales and bats) richness.
Additional figures. (PDF 2190 kb)
Raw data for crania and mandibles for all specimens used in this study including three-dimensiona... more Raw data for crania and mandibles for all specimens used in this study including three-dimensional landmark data (raw coordinates) and identifier; ID_String is the individual combination including all information: Museum (A = Argentina, B = Berlin, H = Halle, K = Kiel, V = Vienna), ID (identifier used at the museum), group (H = horse, D = donkey, P = Przewalski's, Z = zebra), breed (aaa = not a domesticated horse, ahb = Ancient Breed (Roman period), ano = Anglo-Norman, arb = Arab, bif = Birkenfelder, blg = Belgian Draft, bos = Bosnian Pony, cds = Clydesdale, exm = Exmoor Pony, fab = Falabella, gbh = Galician Farm Horse, grb = Grisons (Graubündner), grp = German Riding Pony, han = Hannoverian, hny = Hackney, hol = Holstein, hun = Hungarian, huz = Huzule, ice = Icelandic Horse, ind = Indian Pony, kdr = Kladrubian, kon = Konik, kos = Kosarian, lpz = Lipizzan, mon = Mongolian, nor = Norik, odb = Oldenburgian, piz = Pinzgau, pll = Polish Farm Horse, scp = Scottish Pony, ses = Seneca ...
Table S1. List of cranial landmarks and their placement within the module configurations tested i... more Table S1. List of cranial landmarks and their placement within the module configurations tested in this study. Four modularity hypotheses were tested, see text for further details. Modules for each hypothesis are as follows; 1. Tissue origin – neural crest (NC), paraxial mesoderm (PM); 2. Mammalian modules – anterior oral-nasal (AON), cranial base (CB), cranial vault (CV), molar (M), orbital (ORB), zygomatic pterygoid (ZP); 3. Functional modules – basicranium (B), frontal (F), masticatory (M), nasal (N), oral (O), orbital (OB); 4. Horse-specific – brain (BR), teeth (TE). (DOCX 15 kb)
Palaeontologia Electronica, 2010
The extensive Venezuelan coastline is very important for understanding the evolution of the Carib... more The extensive Venezuelan coastline is very important for understanding the evolution of the Caribbean marine fauna. We report new fossil material collected from three Neogene fossil sites in the Falcon Basin and present the first diversity analysis of the known fossil echinoids from Venezuela and other Caribbean regions. Five species are reported for the first time from Venezuela. Each of the three fossil sites shows a different taxonomic composition, which may be a consequence of differing palaeoecological conditions during the Neogene. Furthermore, the environmental changes caused by the closure of the Central American Isthmus may also have played a role. The analysis of the Venezuelan echinoid fossil record, including the new herein described material, reveals three major diversity decreases and a maximal diversity peak in the Middle Miocene instead of the Eocene as it is the case in other Caribbean echinoid faunas. The first diversity decrease at the end of the Early Cretaceous,...
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Papers by Marcelo Sánchez-Villagra