Category Archives: News

Encounter of the Giants of Berlin

More top quality science from the MfN.

Dinosaurs on Youtube

When we prepared the Spinosaurus exhibition, we realized that both Spinosaurus and T. rex have each a very large and also very emotional fanbase discussing lively whether the two could have met and how a fight would have ended. We have published a video starring Heinrich Mallison, Daniela Schwarz and Nizar Ibrahim looking at the facts and fiction of such online videos and discussions. Enjoy watching it here:https://youtu.be/Rz6vF0MyCnQ. We’d be happy if you like to share the video on your social networks (Twitter: @mfnberlin, Facebook@ Museum für Naturkunde Berlin).

 

New tritylodont from Early Cretaceous of Japan

Hiroshige Matsuoka, Nao Kusuhashi & Ian J. Corfe (2016)
A new Early Cretaceous tritylodontid (Synapsida, Cynodontia, Mammaliamorpha) from the Kuwajima Formation (Tetori Group) of central Japan.

Journal of Vertebrate Paleontology (advance online publication)
DOI: 10.1080/02724634.2016.1112289

http://www.tandfonline.com/doi/full/10.1080/02724634.2016.1112289

We describe tritylodontid remains from the Lower Cretaceous Kuwajima Formation (Tetori Group) in central Japan as representing a new genus, Montirictus kuwajimaensis, gen. et sp. nov. Montirictus is a medium-sized tritylodontid genus characterized by upper cheek teeth having the cusp formula 2-2-2 with subequal cusps, buccal and lingual cusps retaining a crescentic shape with both buccal and lingual ridges anteriorly, and ‘V’-shaped buccolingual cross-sections of two anteroposterior grooves between the three cusp rows. Tentative dating of the Kuwajima Formation to the Barremian-Aptian makes it the stratigraphically youngest representative of a long-lived, globally distributed and abundant mammaliamorph lineage and extends the known geographic range of tritylodontids.

 

Placental Phylogeny

Has this yet passed the scrutiny of our people?

Tarver, J. E., dos Reis, M., Mirarab, S., Moran, R. J., Parker, S., O’Reilly, J. E., King, B. L., O’Connell, M. J., Asher, R. J., Warnow, T., Peterson, K. J., Donoghue, P. C. J. & Pisani, D., 2016:

The Interrelationships of Placental Mammals and the Limits of Phylogenetic Inference.

–Genome Biology and Evolution: Vol. 8, #2, pp. 330-344 [doi: 10.1093/gbe/evv261]

https://gbe.oxfordjournals.org/content/8/2/330.full

Abstract:

Placental mammals comprise three principal clades: Afrotheria (e.g., elephants and tenrecs), Xenarthra (e.g., armadillos and sloths), and Boreoeutheria (all other placental mammals), the relationships among which are the subject of controversy and a touchstone for debate on the limits of phylogenetic inference. Previous analyses have found support for all three hypotheses, leading some to conclude that this phylogenetic problem might be impossible to resolve due to the compounded effects of incomplete lineage sorting (ILS) and a rapid radiation. Here we show, using a genome scale nucleotide data set, microRNAs, and the reanalysis of the three largest previously published amino acid data sets, that the root of Placentalia lies between Atlantogenata and Boreoeutheria. Although we found evidence for ILS in early placental evolution, we are able to reject previous conclusions that the placental root is a hard polytomy that cannot be resolved. Reanalyses of previous data sets rec!

over Atlantogenata + Boreoeutheria and show that contradictory results are a consequence of poorly fitting evolutionary models; instead, when the evolutionary process is better-modeled, all data sets converge on Atlantogenata. Our Bayesian molecular clock analysis estimates that marsupials diverged from placentals 157-170 Ma, crown Placentalia diverged 86-100 Ma, and crown Atlantogenata diverged 84-97 Ma. Our results are compatible with placental diversification being driven by dispersal rather than vicariance mechanisms, postdating early phases in the protracted opening of the Atlantic Ocean.

 

–Mikko

Stones tools from Pliocene hominins in Northwest India dated to 2.6 million years ago

http://www.sciencedirect.com/science/article/pii/S1631068315002286

http://www.sciencedirect.com/science/article/pii/S1631068315002304

http://www.sciencedirect.com/science/article/pii/S1631068315001165

http://www.sciencedirect.com/science/article/pii/S1631068315002110

http://www.sciencedirect.com/science/article/pii/S1631068315002237

http://www.hindustantimes.com/punjab/hollande-modi-hail-indo-french-team-s-findings-at-govt-museum/story-jfrxGfU8zR2cY3Qc4q4ihM.html

http://www.lepoint.fr/science/une-espece-humaine-serait-elle-egalement-nee-au-pied-de-l-himalaya-27-01-2016-2013065_25.php

 

The impact of large terrestrial carnivores on Pleistocene ecosystems

The impact of large terrestrial carnivores on Pleistocene ecosystems

http://www.pnas.org/content/early/2015/10/23/1502554112

Abstract:

Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator–prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.

—
Jussi