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

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

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

Comparative material of modern <i>Varanus</i> for anatomical comparisons with <i>Varanus amnhophilis</i>.

<p>Braincases of <i>Varanus komodoensis</i> (Australasian clade) (A), <i>Varanus bengalensis</i> (<i>Varanus</i> [<i>Indovaranus</i>] group) (B), and <i>Varanus albigularis</i> (<i>Varanus</i> [<i>Polydaedalus</i>]) group) (C). Ventral views of vertebrae of <i>Varanus nebulosus</i> (<i>Varanus</i> [<i>Indovaranus</i>] group) (D), and <i>Varanus flavescens</i> (E). (F) <i>Varanus albigularis</i> cervical vertebra in left dorsolateral view showing the pseudozygosphene. <i>Varanus komodoensis</i> (A) lacks an accessory prootic crest, <i>Varanus bengalensis</i> (B) possesses a hook-like accessory prootic crest, and <i>Varanus albigularis</i> (C) has a tabular accessory prootic crest. Insets with (D) and (E) show the strong and intermediate precondylar constrictions, respectively. Dotted gray lines show the intersection of hypothetical extensions of the ventrolateral surfaces. With a strong precondylar constriction, the lines intersect anterior to the vertebral condyle, but the intersection occurs beyond the level of the condyle in taxa with weak precondylar constriction. Abbreviations: acpr, anterostapedial process of the prootic crest; con, condyle; cpr, prootic crest (crista prootica); pcc, area of precondylar constriction; prz, prezygapophysis; pzgs, pseudozygosphene; syn, synapophysis.</p

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

<p>Fragmentary right postorbital (A) and squamosal (B) in lateral view. (C) Right quadrate in lateral view. (D) Fragmentary palatine in ventral view. Right pterygoid in lateral (E) and ventral (F) view. Note the absence of pterygoid teeth. Right side of the braincase (parabasisphenoid, prootic, basioccipital, and otooccipital) in lateral view (G) and medial view (H). (I) Otic region of the braincase in ventral view showing the base of the crista interfenestralis and single opening to the facial foramen. (J) Reconstruction of the braincase in right lateral view with reconstructed areas appearing as semi-opaque shadows. (K) Partial right surangular-prearticular/articular complex in lateral view. (L) Partial right coronoid in lateral view. (M) Reconstruction of the cranium and mandible in right lateral view with reconstructed areas appearing as semi-opaque shadows. All scale bars 10 mm, except in (I) wherein the scale bar is 5 mm. Abbreviations: apoc, paroccipital tuberosity; acpr, anterostapedial process of the prootic crest; bpt, basipterygoid process; bptb, basipterygoid buttress; colf, columellar fossa; cpr, prootic crest (crista prootica); cri, crista interfenestralis; fec, ectopterygoid facet; fo, fenestra ovalis; fsq, squamosal facet (on postorbital); ipr, inferior process; pbs, parabasisphenoid; pcr, posterior crest; ped, hypapophyseal pedicel; poc, otooccipital paroccipital process; prp, prootic paroccipital process; poz, postzygapophysis; pvc, posterior opening of the vidian canal; qpr, quadrate process; sot, spheno-occipital tubercle; syn, synapophysis; tcr, tympanic crest; tpr, transverse process; I–XII, cranial nerves.</p

Temporally calibrated phylogeny of varanids and their outgroups.

<p>Size data are indicated by color included on the known temporal ranges are derived from published accounts <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Pianka2" target="_blank">[21]</a>, ranges in black indicate taxa without reliable size data. Extant <i>Shinisaurus</i> was used as an outgroup for tree reconstruction, but the shinisaur clade is homogenous in size and extends into the Cretaceous <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767-Conrad2" target="_blank">[3]</a>. Some nodes collapsed for space considerations, but the number of included species is in parentheses next to the taxon name (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767.s001" target="_blank">Dataset S1</a>). Maps present the known distributions of the indicated taxa in red. Mosasaur distribution is based on the five basal taxa included in the analysis. <i>Varanus amnhophilis</i> is a nested member of the Indo-Asian A clade and the discordant distribution of that taxon with respect to other Indo-Asian A taxa is illustrated by the map on the lower left.</p

Size estimates for <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> (AMNH FR 30630) and Megalania (<i>Varanus priscus</i>, BMNH 39965 and AMNH FR 6304) based on comparisons of lateral braincase length (BCL) and dorsal vertebral length (DVL).

<p>The open diamonds indicate <i>Varanus</i> (<i>Varaneades</i>) <i>amnhophilis</i> and the open triangles indicate <i>Varanus priscus</i>. The dotted trend lines was calculated using <i>Varanus komodoensis</i> (PCL/BCL, y intercept [yi] = 17.67, x intercept [xi] = −59.67; PCL/DVL, yi = 44.71, xi = 131.4). The solid gray trend line was calculated using extant species from the Indo-Asian A clade of <i>Varanus</i> (PCL/BCL, yi = 22.08, xi = −85.53, R² = 0.918; PCL/DVL, yi = 42.21, xi = −64–96, R² = 0.994). Solid black trendline was calculated using all the data (PCL/BCL, yi = 17.16, xi = 14.11, R² = 0.956; PCL/DVL, yi = 39.93, xi = −24.20, R² = 0.975). Open line drawing represents <i>Varanus prasinus</i> (Vpr), the medium represents <i>Varanus</i> (<i>Polydaedalus</i>) <i>exanthematicus</i> (Vex), and the large represents <i>Varanus komodoensis</i> (Vko)—all to scale. Gray bars indicate predictive size range within 95 percent confidence interval. See text and (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767.s002" target="_blank">Text S1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041767#pone.0041767.s004" target="_blank">Text S3</a>).</p