Pampean megamammals in Europe: the fossil collections from Santiago Roth

Santiago Roth was a Swiss fossil finder, naturalist, and paleontologist that emigrated to Argentina in 1866. His work largely influenced the discipline in the country at the end of the twentieth century, particularly the stratigraphy of the Pampean region. Some of his collections of Pampean fossils were sold to museums and private collectors in Europe and were accompanied by elaborated catalogues. Fossils in the Roth’s catalogues N° 2 and 3 are housed today in the Natural History Museum of Denmark, fossils from catalogues N° 4 to 6, were sold to Swiss museums, with Catalogue N° 5 currently housed at the Department of Paleontology, Universität Zürich. Here, we provide a general framework on the stratigraphy from the Roth’s Pampean fossil sites, summarize the history of the Pampean fossils in Europe originally collected by Roth, and provide historical and curatorial details of the Roth’s collection at the Department of Paleontology, Universität Zürich

Cranial and Brain Evolution in Late Pleistocene and Domesticated Artiodactyls

This dissertation is a collection of studies on the evolution of the skull and brain systems under the evolutionary model of domestication. Comparative studies of extant versus fossil forms contribute to our understanding of how the brain evolved to the diverse states known today. Thus, one study is devoted to larger-scale patterns in mammalian brain evolution. Artiodactyls encompass the majority of taxa that have been domesticated. They are one of the most morphologically diverse clades within Mammalia, and possess some of the most complex brains after Primates. I apply several new methods three-dimensional shape comparison and brain and body size estimation on several pairs of wild and domestic artiodactyls. Skull shape changes are tested in South American camelids. Brain size changes are tested for camelids, goats, pigs, and cattle. Based on updated phylogenetic data, I critically review the primary literature on brain reduction under domestication for the following mammalian clades: Artiodactyla, Perissodactyla, Carnivora and Glires. Brain size change is explicitly tested among breeds of cattle undergoing differential selection for docility and aggression. Collectively, the studies find some concerted morphological changes correlated with domestication, while others are likely due to other evolutionary factors including phylogeny, development and metabolism. Zusammenfassung Diese Dissertation ist eine Sammlung von Studien zur Evolution des Schädel- und Gehirnsystems unter dem Evolutionsmodell der Domestizierung. Vergleichende Studien von existierenden und fossilen Formen tragen zu unserem Verständnis bei, wie sich das Gehirn zu den heute bekannten verschiedenen Zuständen entwickelt hat. Daher widmet sich eine Studie größeren Mustern in der Gehirnentwicklung von Säugetieren. Paarhufer umfassen die Mehrheit der domestizierten Taxa. Sie sind eine der morphologisch vielfältigsten Kladen innerhalb der Mammalia und besitzen nach Primaten einige der komplexesten Gehirne. Ich wende mehrere neue Methoden, dreidimensionalen Formvergleich und Schätzung der Gehirn- und Körpergröße, an mehreren Paaren wilder und domestizierter Paarhufer an. Veränderungen der Schädelform werden bei südamerikanischen Kameliden getestet. Veränderungen der Gehirngröße werden bei Kameliden, Ziegen, Schweinen und Rindern getestet. Basierend auf aktualisierten phylogenetischen Daten untersuche ich kritisch die Primärliteratur zur Gehirnreduktion unter Domestizierung für die folgenden Säugetiergruppen: Artiodactyla, Perissodactyla, Carnivora und Glires. Die Veränderung der Gehirngröße wird explizit bei Rinderrassen getestet, die einer differentiellen Selektion auf Fügsamkeit und Aggression unterzogen werden. Insgesamt stellen die Studien fest, dass einige konzertierte morphologische Veränderungen mit der Domestizierung korrelieren, während andere wahrscheinlich auf andere evolutionäre Faktoren zurückzuführen sind, darunter Phylogenie, Entwicklung und Stoffwechsel

Description of a fossil camelid from the Pleistocene of Argentina, and a cladistic analysis of the Camelinae

We describe a well-preserved South American Lamini partial skeleton (PIMUZ A/V 4165) from the Ensenadan (~ 1.95–1.77 to 0.4 Mya) of Argentina. The specimen is comprised of a nearly complete skull and mandible with full tooth rows, multiple elements of anterior and posterior limbs, and a scapula. We tested this specimen’s phylogenetic position and hypothesized it to be more closely related to Lama guanicoe and Vicugna vicugna than to Hemiauchenia paradoxa. We formulate a hypothesis for the placement of PIMUZ A/V 4165 within Camelinae in a cladistic analysis based on craniomandibular and dental characters and propose that future systematic studies consider this specimen as representing a new species. For the first time in a morphological phylogeny, we code terminal taxa at the species level for the following genera: Camelops, Aepycamelus, Pleiolama, Procamelus, and Alforjas. Our results indicate a divergence between Lamini and Camelini predating the Barstovian (16 Mya). Camelops appears as monophyletic within the Camelini. Alforjas taylori falls out as a basal member of Camelinae—neither as a Lamini nor Camelini. Pleiolama is polyphyletic, with Pleiolama vera as a basal Lamini and Pleiolama mckennai in a more nested position within the Lamini. Aepycamelus and Procamelus are respectively polyphyletic and paraphyletic. Together, they are part of a group of North American Lamini from the Miocene epoch

Soledad y aislamiento en J.B. Lotz.

Tesis91p

Modularity patterns in mammalian domestication: Assessing developmental hypotheses for diversification

The neural crest hypothesis posits that selection for tameness resulted in mild alterations to neural crest cells during embryonic development, which directly or indirectly caused the appearance of traits associated with the “domestication syndrome” (DS). Although representing an appealing unitary explanation for the generation of domestic phenotypes, support for this hypothesis from morphological data and for the validity of the DS remains a topic of debate. This study used the frameworks of morphological integration and modularity to assess patterns that concern the embryonic origin of the skull and issues around the neural crest hypothesis. Geometric morphometric landmarks were used to quantify cranial trait interactions between six pairs of wild and domestic mammals, comprising representatives that express between five and 17 of the traits included in the DS, and examples from each of the pathways by which animals entered into relationships with humans. We predicted the presence of neural crest vs mesoderm modular structure to the cranium, and that elements in the neural crest module would show lower magnitudes of integration and higher disparity in domestic forms compared to wild forms. Our findings support modular structuring based on tissue origin (neural crest, mesoderm) modules, along with low module integration magnitudes for neural crest cell derived cranial elements, suggesting differential capacity for evolutionary response among those elements. Covariation between the neural crest and mesoderm modules accounted for major components of shape variation for most domestic/wild pairs. Contra to our predictions, however, we find domesticates share similar integration magnitudes to their wild progenitors, indicating that higher disparity in domesticates is not associated with magnitude changes to integration among either neural crest or mesoderm derived elements. Differences in integration magnitude among neural crest and mesoderm elements across species suggest that developmental evolution preserves a framework that promotes flexibility under the selection regimes of domestication

Endocranial Casts of Camelops hesternus and Palaeolama sp.: New Insights into the Recent History of the Camelid Brain

Endocranial casts are capable of capturing the general brain form in extinct mammals due to the high fidelity of the endocranial cavity and the brain in this clade. Camelids, the clade including extant camels, llamas, and alpacas, today display high levels of gyrification and brain complexity. The evolutionary history of the camelid brain has been described as involving unique neocortical growth dynamics which may have led to its current state. However, these inferences are based on their fossil endocast record from approximately ∼40 Mya (Eocene) to ∼11 Mya (Miocene), with a gap in this record for the last ∼10 million years. Here, we present the first descriptions of two camelid endocrania that document the recent history of the camelid brain: a new specimen of Palaeolama sp. from ∼1.2 Mya, and the plaster endocast of Camelops hesternus, a giant camelid from ∼44 to 11 Kya which possessed the largest brain (∼990 g) of all known camelids. We find that neocortical complexity evolved significantly between the Miocene and Pleistocene Epochs. Already ∼1.2 Mya the camelid brain presented morphologies previously known only in extant taxa, especially in the frontal and parietal regions, which may also be phylogenetic informative. The new fossil data indicate that during the Pleistocene, camelid brain dynamics experienced neocortical invagination into the sagittal sinus rather than evagination out of it, as observed in Eocene to Miocene taxa

Paleoneurology of Artiodactyla, an Overview of the Evolution of the Artiodactyl Brain

This chapter presents a detailed review of works published on Artiodactyla endocasts and provides a comprehensive examination of artiodactyl brain evolutionary history, including Cetacea, from the early Eocene (c.a. 45 Ma) onwards. Artiodactyl endocasts have been studied from the second half of the nineteenth century to the 1970s. These works on natural or artificial endocasts widely took place outside the frame of phylogenetic concerns. We compile the data available, including recent works using μCT-scan imagery techniques, and place them in a phylogenetic framework. We also provide new data regarding Paleogene representatives of North American extinct clades (Homacodon, Helohyus, Leptauchenia, Agriochoerus), endemic European clade (Mouillacitherium, Dichobune), and Suoidea (Palaeochoerus). The brain of modern artiodactyls is remarkable by the expansion and by the folding of the neopallium. Their brains are highly gyrencephalic and differ in their neocortical pattern. We highlight diversity of neopallium patterns of Artiodactyla and their convergent nature on the last 45 millions years and show that encephalization increases with time, but with different modes between terrestrial and fully aquatic taxa (i.e. Cetacea). Each clade shows a mosaic pattern of derived and plesiomorphic features that now has to be put in perspective with both the history and ecology of taxa

Holotype locality (circle) for <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> nov. taxon, on Samos, Greece.

<p>Star indicates Athens, Greece.</p

FOSSIL BODY SIZE ESTIMATES.

<p>Body size estimates for fossil varanids (<i>Saniwa ensidens</i>, <i>Varanus amnhophilis</i>, and two specimens of <i>Varanus priscus</i>). Estimates derived from comparisons with the data presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone-0041767-t001" target="_blank">Table 1</a>, as described in the text. Headings/abbreviations: taxon, fossil taxon whose size is predicted; comparisons, taxon group used for making the length estimation; meas., measured element; L, observed length of the measured element in mm; PCL est., estimated precaudal length of the fossil taxon; ±, the difference between the estimated PCL length and the maximum or minimum length falling within a 95 percent confidence interval; BCL, lateral braincase length (see text); DVL, dorsal vertebra length (see text), <i>V.</i>, <i>Varanus</i>; <i>Vko</i>, <i>Varanus komodoensis</i>; <i>Vgo</i>, <i>Varanus gouldii</i>. Underlined measurements indicate those which were deemed most pertinent based on taxonomic comparisons and phylogenetic placement (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone-0041767-g005" target="_blank">Fig. 5</a>) and illustrated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone-0041767-g006" target="_blank">Figure 6</a>.</p

Holotype (AMNH FR 30630) vertebrae for <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> nov. taxon.

<p>(A) Cervical vertebrae 3, 4, and part of 5 in left lateral view. (B) Cervical vertebrae 3 and 4 in posterodorsal view showing the absence of zygosphenes/zygantra and/or pseudozygosphenes/pseudozygantra. (C) Three posterior dorsal vertebrae in ventral view. (D) Reconstruction of AMNH FR 30630 in left lateral view with known parts illustrated on a hypothetical black silhouette for the outline of the animal as a whole. Abbreviations: con, condyle; i, intercentrum; ns, neural spine; pcc, area of precondylar constriction; ped, hypapophyseal pedicel; poz, postzygapophysis; prz, prezygapophysis; syn, synapophysis; zga, zygantrum/pseudozygantrum.</p