The titanotheres of ancient Wyoming, Dakota, and Nebraska

Osborn, Henry Fairfield

doi:10.5962/bhl.title.36431

Cited by 78 publications

(183 citation statements)

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“…The medial epicondyle is transversely wide, but anteroposteriorly short [18,19]. In titanotheres, the lower margin of the medial epicondyle strongly rises, with a relatively large distance from the lower margin of the medial condyle, although the anterior part of the medial margin of the medial condyle in some titanothere forms is distinctly concave [20,21]. In the humeri of rhinoceroses, the medial condyle of the distal trochlea is a comparatively symmetric cone constricted gradually from medially to laterally, and lacks a sagittal groove or ridge to subdivide it [16].…”

Section: Systematic Paleontologymentioning

confidence: 99%

A mammalian fossil from the Dingqing Formation in the Lunpola Basin, northern Tibet, and its relevance to age and paleo-altimetry

et al. 2011

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The distal extremity of a rhinocerotid humerus from the upper part of the Dingqing Formation at the Lunbori locality in Baingoin County, northern Tibet, is the first mammalian fossil found in Cenozoic deposits of the Lunpola Basin. The medial condyle of the distal trochlea of the humerus specimen from Lunbori gradually contracts from medially to laterally. The margin of the medial surface of the medial condyle is not prominent, the well-developed medial epicondyle strongly extends posteriorly, and is divided from the articular facet of the medial condyle by a groove; all of which are characteristic for the Rhinocerotidae. The medial condyle is wide at the bottom and narrow at the top. The medial collateral ligament fossa is relatively shallow, and the medial collateral ligament tubercle is very weak. The medial part of the upper margin of the medial condyle smoothly connects to the bony surface above, but there is no clear boundary between them. All of these characteristics are identical with those of Plesiaceratherium. These comparisons imply that the Lunbori specimen is closest to Plesiaceratherium gracile in the Shanwang Fauna from Linqu, Shandong Province, in size and morphology. Thus, its age is suggested to be the late Early Miocene (Shanwangian Age), about 18-16 Ma. Discovery of the rhinocerotid fossil suggests that the upper part of the Dingqing Formation deposited in the Neogene. While adjusting to paleo-temperatures of the Early Miocene, a paleo-ecosystem reconstruction indicates that the paleoelevation was close to 3000 m in the Lunpola Basin during this time.

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Section: Systematic Paleontologymentioning

confidence: 99%

A mammalian fossil from the Dingqing Formation in the Lunpola Basin, northern Tibet, and its relevance to age and paleo-altimetry

et al. 2011

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“…Limb proportions represent a key feature in the design of any limb (Gatesy & Middleton 1997;Middleton & Gatesy 2000;Gatesy et al 2009;Abourachid & Hö fling 2012), and they have been used to categorise mammals specialised in racing, digging or weight support (Gregory 1912;Osborn 1929;Smith & Savage 1956;Garland & Janis 1993;Gebo & Rose 1993;Carrano 1997Carrano , 1999, and also as an indicator of cursoriality in dinosaurs (e.g., Osborn 1916;Holtz 1994;Ostrom 1976;Coombs 1978;Sereno et al 1996) and even in birds (Gatesy & Middleton 1997;Zeffer et al 2003). However, the actual information on locomotor habits that this can provide has been seriously questioned, particularly in the case of Neornithes.…”

Section: Hind Limb Proportionsmentioning

confidence: 99%

Hind limb morphometry of terror birds (Aves, Cariamiformes, Phorusrhacidae): functional implications for substrate preferences and locomotor lifestyle

Degrange¹

2015

Earth and Environmental Science Transactions of the Royal Socie

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The hind limbs of birds have long been considered a key feature in the conquest of different environments. However, the high level of morphological diversity encountered complicates the foundation of a good theoretical correlation between morphology, locomotor habits and substrate preference and this, in turn, complicates palaeobiological interpretations. Phorusrhacids (Aves, Cariamiformes) are a good example, since they have been unequivocally categorised as terrestrial birds due to their reduced forelimbs; and as apex predators with the ability to pursue prey based only on their hind limb morphology. Multivariate techniques (PCA and discriminant analysis), based on traditional metrics and geomorphometrics of the hind limb and pelvis, were applied in order to explore terrestriality and cursoriality in phorusrhacids. Although several groups of birds could be identified, when looking solely at hind limb metrics, some phorusrhacids appear to be associated with walking birds, while others are associated with cursorial birds. However, the pelvis separates cursorial birds and phorusrhacids from walking and wading birds. This scenario is complicated further by a lack of clear definition of the different locomotor modes and substrate preferences in extant birds, and this makes it difficult to confirm phorusrhacid cursoriality based solely on morphometrics. However, some qualitative features of the pelvis and foot make the picture a little clearer. To study limb adaptations in fossil birds, a more holistic study, with an emphasis on qualitative features of the whole posterior locomotor module, is necessary, since morphometrics leaves some issues unresolved. A comparison with the wings is also needed, in order to make a more complete analysis of locomotor behaviour.

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“…In the Chadronian (late Eocene, formerly thought to be early Oligocene), they reached the culmination of their evolution, becoming elephant-sized beasts whose impressive blunt battering rams on their noses have invited so much speculation. Although we now reject Osborn's (1929) simplistic linear model of evolution and bad taxonomy (Fig. 6), the overall trends in brontothere evolution are still real, even as their taxonomy changed and the phylogeny became more bushy and branching.…”

Section: Rhinos Without Horns Tapirs Without Snoutsmentioning

confidence: 99%

“…The brontotheres ("thunder beasts") or titanotheres (Fig. 6) were long portrayed by the paleontologist Henry Fairfield Osborn (1929) as a continuous gradual lineage that got larger and eventually developed huge paired battering-ram horns on their noses. This outdated notion has been completely revised with modern taxonomy (Mihlbachler 2008), but the general trends are still apparent on their bushy family tree (Fig.…”

Section: Rhinos Without Horns Tapirs Without Snoutsmentioning

confidence: 99%

“…6 Conventional linear view of brontothere evolution through the Eocene from primitive forms like Palaeosyops that are barely distinguishable from contemporary horses through larger and larger forms that eventually developed two blunt horns on their noses (after Osborn 1929) North America and Asia (Gazin 1955;Stucky 1998; chapters in Prothero and Foss 2007), nearly all of which are now extinct. Each of these groups is only slightly more advanced than their primitive sister groups, yet there are already trends toward the low-crowned grinding teeth (bunodonty) in the lineages that led to pigs, peccaries, and hippos (numerous genera from the middle-late Eocene of China and Thailand-Harris and Liu 2007).…”

Section: Cloven Hoovesmentioning

confidence: 99%

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Evolutionary Transitions in the Fossil Record of Terrestrial Hoofed Mammals

Prothero

2009

Evo Edu Outreach

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In the past few decades, many new discoveries have provided numerous transitional fossils that show the evolution of hoofed mammals from their primitive ancestors. We can now document the origin of the odd-toed perissodactyls, their early evolution when horses, brontotheres, rhinoceroses, and tapirs can barely be distinguished, and the subsequent evolution and radiation of these groups into distinctive lineages with many different species and interesting evolutionary transformations through time. Similarly, we can document the evolution of the even-toed artiodactyls from their earliest roots and their great radiation into pigs, peccaries, hippos, camels, and ruminants. We can trace the complex family histories in the camels and giraffes, whose earliest ancestors did not have humps or long necks and looked nothing like the modern descendants. Even the Proboscidea and Sirenia show many transitional fossils linking them to ancient ancestors that look nothing like modern elephants or manatees. All these facts show that creationist attacks on the fossil record of horses and other hoofed mammals are completely erroneous and deceptive. Their critiques of the evidence of hoofed mammal evolution are based entirely on reading trade books and quoting them out of context, not on any firsthand knowledge or training in paleontology or looking at the actual fossils.

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The titanotheres of ancient Wyoming, Dakota, and Nebraska

Cited by 78 publications

References 0 publications

A mammalian fossil from the Dingqing Formation in the Lunpola Basin, northern Tibet, and its relevance to age and paleo-altimetry

A mammalian fossil from the Dingqing Formation in the Lunpola Basin, northern Tibet, and its relevance to age and paleo-altimetry

Hind limb morphometry of terror birds (Aves, Cariamiformes, Phorusrhacidae): functional implications for substrate preferences and locomotor lifestyle

Evolutionary Transitions in the Fossil Record of Terrestrial Hoofed Mammals

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