Category Archives: News

Longer in the tooth, shorter in the record?

Longer in the tooth, shorter in the record? The evolutionary correlates of hypsodonty in Neogene ruminants
P. Raia, F. Carotenuto, J. T. Eronen and M. Fortelius
Proceedings of the Royal Society B
doi: 10.1098/rspb.2011.0273
Abstract
The acquisition of hypsodont molars is often regarded as a key innovation in the history of ruminant ungulates. Hypsodont ruminants diversified rapidly during the later Neogene, circa 15–2 Myr ago, and came to dominate the ruminant fossil record in terms of species diversity. Here we show that hypsodont clades had higher speciation and diversification rates than other clades. Hypsodont species had, on average, shorter stratigraphic durations, smaller range size and lower occupancy than non-hypsodont species. Within hypsodont clades, some species were very common and acquired large geographical ranges, whereas others were quite rare and geographically limited. We argue that hypsodont clades diversified in an adaptive radiation-like fashion, with species often splitting cladogenetically while still in the expansive phase of their occupancy history.

3D Neanderthal comes to a screen near you

Ever wondered what Neanderthals looked like? Or how they walked? Well wonder no more with the London Natural History Museum website’s new augmented reality (AR) Neanderthal.

All you need is a printer and a webcam to see a 3D Neanderthal walk about on your desk, and stop for a stretch, through your computer screen.

http://www.nhm.ac.uk/about-us/news/2011/february/3d-neanderthal-comes-to-a-screen-near-you94923.html

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Laura K. Säilä, PhD

Giant (Easter) bunny found!

The Easter bunny came early this year for a few scientists working on the Spanish island of Minorca.

The team has just announced the discovery of Earth’s biggest known rabbit species, an oddly unbunny-like giant dubbed Nuralagus rex—”the Minorcan king of the hares.”The 26-pound (12-kilogram) prehistoric species was about six times bigger than the common European rabbit, found on most continents, according to an analysis of several bones. The newfound rabbit’s “roly-poly, tanklike” appearance and weird anatomy may have arisen because of its stress-free lifestyle.

http://news.nationalgeographic.com/news/2011/03/110323-giant-rabbit-minorca-biggest-bunny-science-nuralagus-rex-largest/
http://www.vertpaleo.org/source/blog/post.cfm/press-release-giant-extinct-rabbit-was-the-king-of-minorca

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Laura K. Säilä, PhD

Updated chronology for the Miocene hominoid radiation in Western Eurasia

Isaac Casanovas-Vilar, David M. Alba, Miguel Garcés, Josep M. Robles, and Salvador Moyà-Solà
PNAS
Published online before print March 21, 2011,
doi: 10.1073/pnas.1018562108

Abstract
Extant apes (Primates: Hominoidea) are the relics of a group that was much more diverse in the past. They originated in Africa around the Oligocene/Miocene boundary, but by the beginning of the Middle Miocene they expanded their range into Eurasia, where they experienced a far-reaching evolutionary radiation. A Eurasian origin of the great ape and human clade (Hominidae) has been favored by several authors, but the assessment of this hypothesis has been hampered by the lack of accurate datings for many Western Eurasian hominoids. Here we provide an updated chronology that incorporates recently discovered Iberian taxa and further reevaluates the age of many previously known sites on the basis of local biostratigraphic scales and magnetostratigraphic data. Our results show that identifiable Eurasian kenyapithecins (Griphopithecus and Kenyapithecus) are much younger than previously thought (ca. 14 Ma instead of 16 Ma), which casts serious doubts on the attribution of the hominoid tooth from Engelswies (16.3–16.5 Ma) to cf. Griphopithecus. This evidence is further consistent with an alternative scenario, according to which the Eurasian pongines and African hominines might have independently evolved in their respective continents from similar kenyapithecin ancestors, resulting from an early Middle Miocene intercontinental range extension followed by vicariance. This hypothesis, which would imply an independent origin of orthogrady in pongines and hominines, deserves further testing by accurately inferring the phylogenetic position of European dryopithecins, which might be stem pongines rather than stem hominines.

Resources driving landscape-scale distribution patterns of grazers in an African savanna

Ecography 34: 6774, 2011
doi: 10.1111/j.1600-0587.2010.06029.x

Resources driving landscape-scale distribution patterns of grazers in
an African savanna

Izak P. J. Smit

In order to effectively manage and conserve indigenous herbivores, a good understanding is needed of how resources drive their distribution patterns. This study employed a unique dataset to test a range of ecological theories and hypotheses on free-ranging grazers. Using aerial census data collected over 14 yr across the 2 million ha Kruger National Park (South Africa), this study employs spatial autologistic regression models to explore the spatial relationships that exist between the distribution of eight indigenous grazer species and a set of resource variables. It was found that ecological theories relating to feeding guild, water-dependence, allometric scaling, gut-morphology and vulnerability to predation could explain most of the grazer distribution patterns observed in relation to surface-water, forage quality, forage quantity and habitat openness. All the grazers studied were water-dependent and occurred close to a permanent source of water in the dry season. This was ascribed to the lack of moisture in the diet of grazers during the dry season. Most ruminants’ distribution patterns were significantly associated with areas of high forage quality whereas hind-gut fermentors were neutral towards forage quality. Average forage quantity was not a significant predictor of long-term, landscape-scale distribution patterns for any of the grazer species studied. Most small- and medium-bodied grazers preferred open habitats above closed habitats, probably due to higher visibility and a lower predation risk. Large-bodied grazers did not bias their distribution patterns towards open habitats. The way in which grazers distribute themselves with respect to different resources can potentially inform management actions on appropriate scales.

Chinese Paleontologist Raise Doubts About a Cheetah Fossil

In a 24 December 2010 News Focus story in Science, Dr. DENG Tao,  Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, presented a query for a 2009 PNAS paper by Per Christiansen of the Zoological Museum in Copenhagen and Ji H. Mazák of the Shanghai Science and Technology Museum. Christiansen and Mazák reported a new species of the cheetah (Acinonyx kurteni) from the Late Pliocene loess deposits of the Linxia Basin in Gansu Province, China. As a vertebrate paleontologist who specialized on the Late Cenozoic mammals of the Linxia Basin for many years, Deng naturally had particular interests in reading this paper. Having carefully checked the described skull in this paper’s figures, unfortunately, he found that Christiansen and Mazák studied a fossil forgery, the sole foundation of the paper. In a 4 March 2011 letter in Science, Mazák and Christiansen note “the occipital area and zygomatic arches have been heavily restored in plaster, probably to make it appear more complete, thus enhancing its commercial value, a common malpractice among Chinese fossil dealers.” Deng and his colleague responded, also in Science, that they are pleased to see this note, but stand by their view that the skull is a composite with fabricated features.

Read more at: http://english.ivpp.cas.cn/ns/es/201103/t20110304_65943.html

– Majid

Dietary Change and Evolution of Horses in North America

Dietary Change and Evolution of Horses in North America
Matthew C. Mihlbachler, Florent Rivals, Nikos Solounias, Gina M. Semprebon

The evolution of high-crowned molars among horses (Family Equidae) is thought to be an adaptation for abrasive diets associated with the spread of grasslands. The sharpness and relief of the worn cusp apices of teeth (mesowear) are a measure of dietary abrasion. We collected mesowear data for North American Equidae for the past 55.5 million years to test the association of molar height and dietary abrasion. Mesowear trends in horses are reflective of global cooling and associated vegetation changes. There is a strong correlation between mesowear and crown height in horses; however, most horse paleopopulations had highly variable amounts of dietary abrasion, suggesting that selective pressures for crown height may have been weak much of the time. However, instances of higher abrasion were observed in some paleopopulations, suggesting intervals of stronger selection for the evolution of dentitions, including the early Miocene shortly before the first appearance of Equinae, the horse subfamily in which high-crowned dentitions evolved.

Science 4 March 2011:
Vol. 331 no. 6021 pp. 1178-1181
DOI: 10.1126/science.1196166

Has the Earth’s sixth mass extinction already arrived?

Has the Earth’s sixth mass extinction already arrived?

Anthony D. Barnosky, Nicholas Matzke, Susumu Tomiya, Guinevere O. U.Wogan, Brian Swartz, Tiago B. Quental,
Charles Marshall, Jenny L. McGuire, Emily L. Lindsey, Kaitlin C. Maguire, Ben Mersey & Elizabeth A. Ferrer

Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

http://www.nature.com/nature/journal/v471/n7336/full/nature09678.html

Newsflash: Diversity and evolution of Hunter-Schreger Band configuration in tooth enamel of perissodactyl mammals

Diversity and evolution of Hunter-Schreger Band configuration in tooth enamel of perissodactyl mammals

Wighart Von Koenigswald, Luke T. Holbrook, and Kenneth D. Rose

Acta Palaeontologica Polonica 56 (1), 2011: 11-32 doi:10.4202/app.2010.0021

Four different Hunter−Schreger Band (HSB) configurations were observed in the teeth of fossil and extant Perissodactyla. This variability exceeds that observed in Artiodactyla or Proboscidea. The four HSB configurations represent two different evolutionary pathways. Transverse HSB found in many mammalian taxa outside the Perissodactyla represents the most primitive HSB configuration. It occurs in several primitive perissodactyl families and is retained in Palaeotheriidae and extant Equidae. Curved HSB evolved from transverse HSB and occurs in Tapiridae, Helaletidae, and Lophiodontidae, as well as in Ancylopoda and Titanotheriomorpha. This likely indicates independent evolution of curved HSB in two or more lineages, but the number of instances of parallelism of this configuration is obscured by uncertainty in the relationships among these taxa and by a lack of data for some important basal taxa. A second evolutionary pathway leads from transverse HSB via compound HSB to vertical HSB. Compound HSB were detected in Hyrachyidae, Deperetellidae, and the early rhinocerotid Uintaceras. Vertical HSB configuration characterizes the molar dentition of other Rhinocerotidae, Hyracodontidae, Indricotheriidae, andAmynodontidae. Often, the incisors of rhinocerotids retain traces of compound HSB. Thus theHSB configuration reflects phylogenetic relationships to some degree. The selective value of themodified HSB configurations is interpreted functionally as amechanismto reduce abrasion duringmastication, assuming that the perpendicular intersection of prismswith the actual grinding surfaces resists wear better than prisms running parallel to the occlusal surface.

-Mikko