[PaleoMammalogy • 2022] Multituberculate Mammals Show Evidence of a Life History Strategy Similar to That of Placentals, Not Marsupials

a Mesodma mother with her relatively precocial offspring

in Weaver, Fulghum, ... et Whitney, 2022. 

DOI: 10.1086/720410 

  twitter.com/LukeNWeave 

artwork by Andrey Atuchin 

Abstract

The remarkable evolutionary success of placental mammals has been partly attributed to their reproductive strategy of prolonged gestation and birthing of relatively precocial, quickly weaned neonates. Although this strategy was conventionally considered derived relative to that of marsupials with highly altricial neonates and long lactation periods, mounting evidence has challenged this view. Until now the fossil record has been relatively silent on this debate, but here we find that proportions of different bone tissue microstructures in the femoral cortices of small extant marsupials and placentals correlate with length of lactation period, allowing us to apply this histological correlate of reproductive strategies to Late Cretaceous and Paleocene members of Multituberculata, an extinct mammalian clade that is phylogenetically stemward of Theria. Multituberculate bone histology closely resembles that of placentals, suggesting that they had similar life history strategies. A stem-therian clade exhibiting evidence of placental-like life histories supports the hypothesis that intense maternal-fetal contact characteristic of placentals is ancestral for therians. Alternatively, multituberculates and placentals may have independently evolved prolonged gestation and abbreviated lactation periods. Our results challenge the hypothesis that the rise of placental mammals was driven by unique life history innovations and shed new light on early mammalian diversification.

Keywords: bone histology, marsupial-placental dichotomy, reproduction, lactation, weaning, multituberculates

Lucas N. Weaver, Henry Z. Fulghum, David M. Grossnickle, William H. Brightly, Zoe T. Kulik, Gregory P. Wilson Mantilla and Megan R. Whitney. 2022. Multituberculate Mammals Show Evidence of a Life History Strategy Similar to That of Placentals, Not Marsupials. The American Naturalist. DOI: 10.1086/720410 

  twitter.com/LukeNWeaver/status/1549114239763169280

 @ASNAmNat  @AndreyAtuchin

[PaleoMammalogy • 2015] Kimbetopsalis simmonsae • A New Taeniolabidoid Multituberculate (Mammalia) from the middle Puercan of the Nacimiento Formation, New Mexico, and A Revision of Taeniolabidoid Systematics and Phylogeny

Kimbetopsalis simmonsae

Williamson, Brusatte, Secord & Shelley, 2015
DOI: 10.1111/zoj.12336 | newsroom.UNL.edu

Multituberculates were amongst the most abundant and taxonomically diverse mammals of the late Mesozoic and the Palaeocene, reaching their zenith in diversity and body size in the Palaeocene. Taeniolabidoidea, the topic of this paper, includes the largest known multituberculates, which possess highly complex cheek teeth adapted for herbivory. A new specimen from the early Palaeocene (middle Puercan; biochron Pu2) of the Nacimiento Formation, New Mexico represents a new large-bodied taeniolabidoid genus and species, Kimbetopsalis simmonsae. A phylogenetic analysis to examine the relationships within Taeniolabidoidea that includes new information from Kimbetopsalis gen. et sp. nov. and gen. nov. and from new specimens of Catopsalis fissidens, first described here, and data from all other described North American and Asian taeniolabidoids. This analysis indicates that Catopsalis is nonmonophyletic and justifies our transfer of the basal-most taeniolabidoid ‘Catopsalis’ joyneri to a new genus, Valenopsalis. Kimbetopsalis and Taeniolabis form a clade (Taeniolabididae), as do the Asian Lambdopsalis, Sphenopsalis, and possibly also Prionessus (Lambdopsalidae). Taeniolabidoids underwent a modest taxonomic radiation during the early Palaeocene of North America and underwent a dramatic increase in body size, with Taeniolabis taoensis possibly exceeding 100 kg. Taeniolabidoids appear to have gone extinct in North America by the late Palaeocene but the appearance of lambdopsalids in the late Palaeocene of Asia suggests that they dispersed from North America in the early to middle Palaeocene. 

Keywords: body size; dispersal; ecological recovery; mammalian radiation; multituberculata; palaeobiogeography; Palaeocene; San Juan Basin; Taeniolabididae; Taeniolabidoidea

Systematic palaeontology

Mammalia Linnaeus, 1758

Multituberculata Cope, 1884

Taeniolabidoidea Sloan & Van Valen, 1965

Taeniolabididae Granger & Simpson, 1929

Kimbetopsalis simmonsae gen. et sp. nov. (Figs 1, 2, Tables 1 and 2) 

(http://zoobank.org/urn:lsid:zoobank.org:pub:9E9F07C3-D042-4E8F-862A-279072E04035)

Holotype: NMMNH P-69902 from locality L-9181.

The jaws of Kimbetopsalis simmonsae.

A reconstruction of Kimbetopsalis simmonsae, a rodent-like multituberculate mammal species discovered during a 2014 fossil hunting trip

Illustration: Sarah Shelley, University of Edinburgh

Type locality and horizon: The specimen was discovered in the lower Palaeocene part of the Nacimiento Formation of the San Juan Basin of northwestern New Mexico, in the west flank of Kimbeto Wash, at locality 11 of Williamson (1996: fig. 18). It is from Fossil Horizon A and within the Hemithlaeus kowalevskianus – Taeniolabis taoensis Biozone (H-T Zone) (Williamson, 1996). The vertebrate fauna from this horizon is considered part of the type faunas of the middle Puercan Interval Zone (Pu2) (Archibald et al., 1987; Williamson, 1996; Lofgren et al., 2004).

The west flank of Kimbeto Wash has yielded numerous taxa that are restricted to the H-T Zone, including Hemithlaeus kowalevskianus and Conacodon entoconus. These taxa are particularly abundant in H-T Zone faunas of the Nacimiento Formation, but are absent from the overlying Fossil Horizon B that yields the type faunas of the late Puercan Interval Zone (Pu3) (Williamson, 1996). Furthermore, no specimens of T. taoensis have been recovered from the west flank of Kimbeto Wash. This is important because the first occurrence of Taeniolabis defines the beginning of the Pu3 Interval Zone (Archibald et al., 1987; Lofgren et al., 2004). Although it does not in itself support a Pu2 age for the locality, the absence of Taeniolabis is further evidence that the west flank of Kimbeto Wash is not Pu3 in age (a time when other large taeniolabidids are known from the Nacimiento Formation). Specimen NMMNH P-69902 was found fragmented, but in close association, weathering from a silty mudstone in an area of low relief. There is no possibility that the specimen is float from a higher horizon and therefore we are confident that it is a member of the H-T Zone fauna, and thus is Pu2 in age.

Etymology: Kimbeto, for Kimbeto Wash; psalis, ‘cutting shears’ (Greek). Simmonsae, after Nancy Simmons, in recognition of her work on taeniolabidoid multituberculates.

Valenopsalis gen. nov.

Etymology: Named after the late Leigh Van Valen, one of the 20th century's great mammalian palaeontologists, who studied Cretaceous–Palaeogene multituberculates (including ‘Ca.’ joyneri) and was a colourful inspiration to T. E. W. (who fondly remembers Leigh's visit to the NMMNH collections when he was a graduate student) and S. L. B. (when he was an undergraduate student in Chicago).

Type species: Catopsalis joyneri Sloan & Van Valen, 1965.

Included species: Type species only.

Distribution: Early Puercan (Pu1) of eastern Montana.

Conclusions

The recovery of a new genus and species of large taeniolabidoid multituberculate, Ki. simmonsae, from the early Palaeocene (middle Puercan; Pu2) of the Nacimiento Formation prompted a revision of Taeniolabidoidea and an evaluation of their phylogeny and evolution. Our phylogenetic analysis of Taeniolabidoidea included all Asian and North American species referable to this clade. Owing to uncertainties over the choice of an appropriate outgroup we ran analyses using five different outgroups and found that trees were highly resolved using three (Cimo. gracilis, Men. robustus, and Mi. conus) of the five outgroups. In the highly resolved trees, species of the largest-bodied North American forms, Kimbetopsalis and Taeniolabis, consistently form a monophyletic clade as do species of the Asian Lambdopsalis, Sphenopsalis, and Prionessus. We here define Kimbetopsalis and Taeniolabis as the basis of Taeniolabididae and Lambdopsalis and Sphenopsalis as the basis of Lambdopsalidae.

This study underscores the extreme rapidity of development of large body size and the increase in dental complexity within taeniolabidoids within the first 800 Kyr of the end-Cretaceous mass extinction (Wilson et al., 2012; Williamson et al., 2014). Taeniolabidoids evolved extremely unusual and highly specialized, large, chisel-shaped incisors and massive, multicusped cheek teeth for grinding vegetation and attained large body masses, exceeding 20 kg. The shifts to larger body sizes and increased cusp complexity strongly suggest a shift toward herbivory, and possibly folivory.

Figure 6. Time-calibrated phylogeny based on the most-resolved consensus tree from our phylogenetic analyses. Each taxon is accompanied by a silhouette that illustrates the relative sizes resulting from our mass estimates (Table 4; skull length – m1 estimate).

The area of the silhouette is proportionate to the mass [ln(area) = 0.6667*ln(volume) + 0.231]. The time scale follows Ogg (2012). The placement of the Puercan faunas of the Nacimiento Formation is after Williamson et al. (2014). Asian Palaeocene mammal biochronology is after Ting et al. (2011). Fm., Formation. DOI: 10.1111/zoj.12336

Bubodens magnus, the largest multituberculate and largest mammal of the latest Cretaceous, probably represents the sole Cretaceous representative of Taeniolabidoidea. Taeniolabidoids of the earliest Palaeocene faunas of North America include V. joyneri, which our phylogenetic analyses found to be the basal-most taeniolabidoid. We find that Kimbetopsalis simmonsae is the basal-most member of Taeniolabididae and it provides a plausible progenitor for T. taoensis, which first appeared in the San Juan Basin within the next 200 Kyr.

Although taeniolabidoids disappeared from North America several million years before the end of the Palaeocene, they dispersed to Asia where they underwent a subsequent modest radiation towards the end of the Palaeocene, becoming extinct near the Palaeocene–Eocene boundary.

 Thomas E. Williamson, Stephen L. Brusatte, Ross Secord, and Sarah Shelley. 2015. A New Taeniolabidoid Multituberculate (Mammalia) from the middle Puercan of the Nacimiento Formation, New Mexico, and A Revision of Taeniolabidoid Systematics and Phylogeny. Zoological Journal of the Linnean Society. DOI: 10.1111/zoj.12336

Paleo Profile: Kimbetopsalis simmonsae http://on.natgeo.com/1VEJwHs via  @NGPhenomena

This massive furry rodent outlived the dinosaurs http://www.slashgear.com/this-massive-furry-rodent-outlived-the-dinosaurs-05407846/ via @slashgear

http://www.sci-news.com/paleontology/science-kimbetopsalis-simmonsae-mammal-03305.html

http://newsroom.unl.edu/releases/2015/10/05/Fossil+find%3A+UNL+undergraduate+discovers+new+mammal+species

Reviving the Woolly Mammoth: Will De-Extinction Become Reality?

This photo shows a museum worker inspecting a replica of a woolly mammoth (Mammuthus primigenius), a relative of modern elephants that went extinct 3,000 to 10,000 years ago.

 Photo by Jonathan S. Blair/National Geographic

Biologists briefly brought the extinct Pyrenean ibex back to life in 2003 by creating a clone from a frozen tissue sample harvested before the goat's entire population vanished in 2000. The clone survived just seven minutes after birth, but it gave scientists hope that "de-extinction," once a pipedream, could become a reality.

Ten years later, a group of researchers and conservationists gathered in Washington, D.C., today (March 15) for a forum called TEDxDeExtinction, hosted by the National Geographic Society, to talk about how to revive extinct animals, from the Tasmanian tiger and the saber-toothed cat to the woolly mammoth and the North American passenger pigeon.

Though scientists don't expect a real-life "Jurassic Park" will ever be on the horizon, a species that died a few tens of thousands of years ago could be resurrected as long as it has enough intact ancient DNA.


Some have their hopes set on the woolly mammoth, a relative of modern elephants that went extinct 3,000 to 10,000 years ago and left behind some extraordinarily well preserved carcasses in Siberian permafrost. Scientists in Russia and South Korea have embarked on an ambitious project to try to create a living specimen using the DNA-storing nucleus of a mammoth cell and an Asian elephant egg — a challenging prospect, as no one has ever been able to harvest eggs from an elephant.



But DNA from extinct species doesn't need to be preserved in Arctic conditions to be useful to scientists — researchers have been able to start putting together the genomes of extinct species from museum specimens that have been sitting on shelves for a century. If de-extinction research has done anything for science, it's forced researchers to look at the quality of the DNA in dead animals, said science journalist Carl Zimmer, whose article on de-extinction featured on the cover of the April issue of National Geographic magazine.

"It's not that good but you can come up with techniques to retrieve it," Zimmer told LiveScience.

For instance, a team that includes Harvard genetics expert George Church is trying to bring back the passenger pigeon — a bird that once filled eastern North America's skies. They have been able to piece together roughly 1 billion letters (Each of four nucleotides that make up DNA has a letter designation) in the bird's genome based on DNA from a 100-year-old taxidermied museum specimen. They hope to incorporate those genes responsible for certain traits into the genome of a common rock pigeon to bring back the passenger pigeon, or at least create something that looks like it.

A few years ago, another group of researchers isolated DNA from a 100-year-old specimen of a young thylacine, also known as Tasmanian tiger. The pup had been preserved in alcohol at Museum Victoria in Melbourne. Its genetic material was inserted into mouse embryos, which proved functional in live mice.

......

Reviving the Woolly Mammoth: Will De-Extinction Become Reality? http://www.livescience.com/27939-reviving-extinct-animals-mammoths.html via @LiveScience

[Paleomammalogy • 2011] Late Pleistocene steppe lion Panthera leo spelaea (Goldfuss, 1810) footprints and bone records from open air sites in northern Germany – Evidence of hyena-lion antagonism and scavenging in Europe

Abstract 

Bone remains and a trackway of Pantheraichnus bottropensis nov. ichg. ichnsp. of the Late Pleistocene lion Panthera leo spelaea (Goldfuss, 1810) have been recovered from Bottrop and other open air sites in northern Germany. Some of these bones are from open air hyena den sites. A relative high proportion of lion bones (20%) exhibit bite, chew or nibble marks, or bone crushing and nibbling caused by a large carnivore. Repeated patterns of similar bone damage have been compared to bone remains found at hyena dens in gypsum karst areas and cave sites in northern Germany. Ice Age spotted hyenas have been the main antagonists and the main scavengers on lion carcasses. The remains appear to have been imported often by hyenas into their communal dens, supporting the theory of strong hyena-lion antagonism, similar to the well documented antagonism between modern African lions and spotted hyenas. Most of the lion bones from the open air hyena den at Bottrop are probably a result of such antagonism, as are the rare remains of these carnivores found within large hyena prey bone accumulations along the Pleistocene rivers. The Emscher River terrace also has the largest quantity of hyena remains from open air river terrace sites in northern Germany. Their cub remains, and incomplete chewed prey bones from mammoths and woolly rhinoceroses, typical of hyena activity, underline the character of these sites as cub-raising and communal dens, where their prey was accumulated along the riverbanks in a similar manner to modern African hyenas. 

Keywords: Panthera leo spelaea; Open air sites; Northern Germany; Late Pleistocene; Bone taphonomy; Palaeoecology; Biogeography

Spotted hyenas scavenge a lion carcass at an open-air, grassland site in Pleistocene Europe. Image by G. “Rinaldino” Teichmann and from Diedrich, 2011.

Diedrich, C. 2011. Late Pleistocene steppe lion Panthera leo spelaea (Goldfuss, 1810) footprints and bone records from open air sites in northern Germany – Evidence of hyena-lion antagonism and scavenging in Europe. Quaternary Science Reviews. 30 (15-16), 1883-1906. DOI: 10.1016/j.quascirev.2011.03.006

Lions vs. Hyenas -- A Long-Running, Pleistocene Rivalry  

http://www.wired.com/wiredscience/2011/09/lions-vs-hyenas-a-long-running-pleistocene-rivalry/

[Cetology • 2012] Miocaperea pulchra • Comparative osteology and phylogenetic relationships of Miocaperea pulchra, the first fossil pygmy right whale (Cetacea, Mysticeti, Neobalaenidae) | found from the upper Miocene Pisco Formation at Aguada de Loma, Peru

the skulls of Caperea (left) and Miocaperea (right), from Bisconti (2012).

photo: http://coastalpaleo.blogspot.com/

Abstract 

A fossil pygmy right whale (Cetacea, Mysticeti, Neobalaenidae) with exquisitely preserved baleen is described for the first time in the history of cetacean palaeontology, providing a wealth of information about the evolutionary history and palaeobiogeography of Neobalaenidae. This exquisitely preserved specimen is assigned to a new genus and species, Miocaperea pulchra gen. et sp. nov., and differs from Caperea marginata Gray, 1846, the only living taxon currently assigned to Neobalaenidae, in details of the temporal fossa and basicranium. A thorough comparative analysis of the skeleton of M. pulchra gen. et sp. nov. and C. marginata is also provided, and forms the basis of an extensive osteology-based phylogenetic analysis, confirming the placement of M. pulchra gen. et sp. nov. within Neobalaenidae as well as the monophyly of Neobalaenidae and Balaenidae; the phylogenetic results support the validity of the superfamily Balaenoidea. No relationship with Balaenopteroidea was found by the present study, and thus the balaenopterid-like morphological features observed in C. marginata must have resulted from parallel evolution. The presence of M. pulchra gen. et sp. nov. around 2000 km north from the northernmost sightings of C. marginata suggests that different ecological conditions were able to support pygmy right whale populations in what is now Peru, and that subsequent environmental change caused a southern shift in the distribution of the living neobalaenid whales.

Keywords: Balaenoidea; Caperea marginata; Miocene; Peru; phylogeny 

Three-dimensionally preserved baleen in Miocaperea

Bisconti, M. 2012. Comparative osteology and phylogenetic relationships of Miocaperea pulchra, the first fossil pygmy right whale genus and species (Cetacea, Mysticeti, Neobalaenidae). Zoological Journal of the Linnean Society. 166: 876-911. DOI: 10.1111/j.1096-3642.2012.00862.x 

[Paleomammalogy • 2011] Coelodonta thibetana • Out of Tibet: Pliocene Woolly Rhino Suggests High-Plateau Origin of Ice Age Megaherbivores

Ice Age megafauna have long been known to be associated with global cooling during the Pleistocene, and their adaptations to cold environments, such as large body size, long hair, and snow-sweeping structures, are best exemplified by the woolly mammoths and woolly rhinos. These traits were assumed to have evolved as a response to the ice sheet expansion. We report a new Pliocene mammal assemblage from a high-altitude basin in the western Himalayas, including a primitive woolly rhino. These new Tibetan fossils suggest that some megaherbivores first evolved in Tibet before the beginning of the Ice Age. The cold winters in high Tibet served as a habituation ground for the megaherbivores, which became preadapted for the Ice Age, successfully expanding to the Eurasian mammoth steppe.

A, Skull and cheek teeth of Coelodonta thibetana. 

B, Origin, distribution, and dispersal of woolly rhinos in Eurasia.

(Image by DENG Tao)

 

Skull and lower jaw of the extinct Tibetan woolly rhino, Coelodonta thibetana. 

Credit: DENG Tao

A paper in Science reveals the discovery of a primitive woolly rhino fossil in the Himalayas, which suggests some giant mammals first evolved in present-day Tibet before the beginning of the Ice Age. The extinction of Ice Age giants such as woolly mammoths and rhinos, giant sloths, and saber-tooth cats has been widely studied, but much less is known about where these giants came from, and how they acquired their adaptations for living in a cold environment.

A team of geologists and paleontologists led by Xiaoming Wang from the Natural History Museum of Los Angeles County (NHM) and Qiang Li of Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, uncovered a complete skull and lower jaw of a new species of woolly rhino (Coelodonta thibetana) in 2007, at the foothills of the Himalayas in southwestern Tibetan Plateau.

"Cold places, such as Tibet, Arctic, and Antarctic, are where the most unexpected discoveries will be made in the future — these are the remaining frontiers that are still largely unexplored," said the NHM's Dr. Wang.

Reconstruction of Coelodonta thibetana (Illustrated by Julie Naylor)

The new rhino is 3.6 million years old (middle Pliocene), much older and more primitive than its Ice Age (Pleistocene) descendants in the mammoth steppes across much of Europe and Asia. The extinct animal had developed special adaptations for sweeping snow using its flattened horn to reveal vegetation, a useful behavior for survival in the harsh Tibetan climate. These rhinos lived at a time when global climate was much warmer and the northern continents were free of the massive ice sheets seen in the Ice Age later.

The rhino accustomed itself to cold conditions in high elevations and became pre-adapted for the future Ice Age climate. When the Ice Age eventually arrived around 2.6 million years ago, the new paper posits, the cold-loving rhinos simply descended from the high mountains and began to expand throughout northern Asia and Europe.

In addition to the new woolly rhino, the paleontologist team also uncovered extinct species of three-toed horse (Hipparion), Tibetan bharal (Pseudois, also known as blue sheep), chiru (Pantholops, also known as Tibetan antelope), snow leopard (Uncia), badger (Meles), as well as 23 other kinds of mammals.

The team's new fossil assemblage from Tibet offers new insights into the origin of the cold-adapted Pleistocene megafauna, which has usually been sought either in the arctic tundra or in the cold steppes elsewhere. This new evidence offers an alternative scenario: the harsh winters of the rising Tibetan Plateau may have provided the initial step towards cold-adaptation for several subsequently successful members of the late Pleistocene mammoth fauna in Europe, Asia, and to a lesser extent, North America. The Tibetan Plateau may have been another cradle of the Ice Age giants.

"This discovery clarifies the origin of the woolly rhinoceros — and perhaps much of the now extinct, cold-adapted, Pleistocene Eurasian megafauna — as the high-altitude environments of the Zanda Basin of the primordial Pliocene Himalayas," said H. Richard Lane of the National Science Foundation (NSF)'s Division of Earth Sciences.

A, Phylogenetic position of Coelodonta thibetana.  

Deng, T., Wang, X., Fortelius, M., Li, Q., Wang, Y., Tseng, Z.J., Takeuchi, G.T., Saylor, J.E., Säilä, L.K. & Xie, G. 2011. Out of Tibet: Pliocene Woolly Rhino Suggests High-Plateau Origin of Ice Age Megaherbivores. Science. 6047: 1285–1288. doi:10.1126/science.1206594

http://www.sciencemag.org/content/333/6047/1285

Discovery: new woolly rhino species Coelodonta thibetana | Science Codex 

http://www.sciencecodex.com/natural_history_museum_of_los_angeles_county_announces_discovery_of_important_woolly_rhino_fossil

Out of Tibet: Ancestral Woolly Rhino Suggests Origin of Ice Age Megaherbivores in High Plateau

http://english.ivpp.cas.cn/rh/rp/201109/t20110902_74549.html

[Exhibition 2012] Livyatan: ‘The biggest mouth ever’ | ‘De grootste muil ooit’

‘The biggest mouth ever’ | ‘De grootste muil ooit’

at Natuurhistorisch Museum Rotterdam

http://www.nmr.nl/nmr/pages/showPage.do?instanceid=21&itemid=12369&style=default

http://www.nmr.nl/nmr/locale/select.do?scope=ui&localeid=en_GB

Livyatan melvillei (Lambert et al. 2010) • The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru: http://novataxa.blogspot.com/2012/06/2010-leviathan-livyatan-melvillei.html

http://dinorider.blogspot.com/2012/06/livyatan-vs-kentriodon-de-grootste-beet.html

[Paleontology • 2010] Livyatan melvillei (originally Leviathan) • The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru

Livyatan melvillei (Lambert et al., 2010)

Synonym: Leviathan melvillei Lambert et al., 2010

The modern giant sperm whale Physeter macrocephalus, one of the largest known predators, preys upon cephalopods at great depths. Lacking a functional upper dentition, it relies on suction for catching its prey3; in contrast, several smaller Miocene sperm whales (Physeteroidea) have been interpreted as raptorial (versus suction) feeders, analogous to the modern killer whale Orcinus orca. Whereas very large physeteroid teeth have been discovered in various Miocene localities, associated diagnostic cranial remains have not been found so far. Here we report the discovery of a new giant sperm whale from the Middle Miocene of Peru (approximately 12–13 million years ago), Leviathan melvillei, described on the basis of a skull with teeth and mandible. With a 3-m-long head, very large upper and lower teeth (maximum diameter and length of 12 cm and greater than 36 cm, respectively), robust jaws and a temporal fossa considerably larger than in Physeter, this stem physeteroid represents one of the largest raptorial predators and, to our knowledge, the biggest tetrapod bite ever found. The appearance of gigantic raptorial sperm whales in the fossil record coincides with a phase of diversification and size-range increase of the baleen-bearing mysticetes in the Miocene. We propose that Leviathan fed mostly on high-energy content medium-size baleen whales. As a top predator, together with the contemporaneous giant shark Carcharocles megalodon, it probably had a profound impact on the structuring of Miocene marine communities. The development of a vast supracranial basin in Leviathan, extending on the rostrum as in Physeter, might indicate the presence of an enlarged spermaceti organ in the former that is not associated with deep diving or obligatory suction feeding.

http://pablolarailustracion.blogspot.com/2011/11/llamenme-livyatan.html

Lambert, Olivier; Giovanni Bianucci, Klaas Post, Christian de Muizon, Rodolfo Salas-Gismondi, Mario Urbina, and Jelle Reumer. 2010. The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru. Nature. 466 (7302): 105–108. DOI:10.1038/nature09067

http://dinorider.blogspot.com/2010/06/fosil-de-miercoles-leviathan-melvillei.html

http://dinorider.blogspot.com/2012/06/livyatan-vs-kentriodon-de-grootste-beet.html

[Paleontology/Mammalogy • 2010] Nesolagus sinensis • First discovery of fossil Nesolagus (Leporidae, Lagomorpha) from Southeast Asia

A new leporid species, Nesolagus sinensis sp. nov., is described here representing the only leporid ember of the Early Pleistocene Gigantopithecus fauna from Sanhe Cave, Chongzuo, Guangxi, South China and also the first fossil taxon of the Southeast Asian genus Nesolagus. Compared with two extant Nesolagus species from Indonesia and Vietnam and other related leprids, the new species has a relatively small size and an extraordinarily weak anterior internal reentrant (AIR) on p3, but it also retains the simplified paedomorphic pattern during the ontogenetic process as in extant species, which suggests that the new species is more primitive than and probably directly ancestral to extant Nesolagus species. The new species seems closely related to Alilepus longisinuosus from the Late Miocene strata of Lufeng, Yunnan, and probably diverged from a leporid similar to its ancestral form. It also indicates that Nesolagus originated in Southwest China.

Keywords: Guangxi of China, Early Pleistocene, Nesolagus sinensis sp. nov., Gigantopithecus fauna

Order Lagomorpha Brandt, 1885

Family Leporidae Gray, 1821

Genus Nesolagus Forsyth Major, 1899

Type species   Nesolagus netscheri (Schlegel, 1880)

Nesolagus sinensis sp. nov. (Figures 3 and 4)

Holotype: Fragmentary ramus of a left mandible with fragmentary incisor and p3 to m3 (IVPP V15932).

Type locality: Wuming Mountain in Chongzuo Ecological Park in Guangxi Zhuang Autonomous Region.

Geological age: Middle Early Pleistocene.

Etymology: Named for the first discovery of Nesolagus fossil in China (after Greek “Sino”, pertaining to China and the Chinese).

Citation:   Jin C Z, Tomida Y, Wang Y, et al. 2010. First discovery of fossil Nesolagus (Leporidae, Lagomorpha) from Southeast Asia. Sci China Earth Sci. 53: 1134–1140, doi: 10.1007/s11430-010-4010-3

[Mammalogy • 2011] Nuralagus rex | Minorcan Giant Lagomorph • an endemic insular giant rabbit from the Neogene of Minorca (Balearic Islands, Spain)

Abstract

We describe a new insular endemic lagomorph from the Late Neogene karstic deposits of Minorca (Balearic islands, Spain). Nuralagus rex, gen. et sp. nov., is characterized by an array of odd traits unknown for lagomorphs. Most outstanding are the gigantic size (average 12 kg), the robust postcranial skeleton with unique morphological traits (short manus and pes with splayed phalanges, short and stiff vertebral column with reduced extension/flexion capabilities), and the relatively small size of sense-related areas of the skull (tympanic bullae, orbits, braincase, and choanae). These morphological traits denote an important decrease in locomotor and neurological activities and, hence, a decrease in metabolic energy expenditure, which is concordant with the ecological conditions of the insular environment characterized by absence of predators and low levels of resource supply. Our discovery enhances the importance of the frequently neglected fossil record for our understanding evolution on islands, because it provides the perspective of time and adds valuable data from fossil insular ecosystems unaffected by anthropogenic alterations.

Nuralagus rex — Giant Extinct Rabbit was the King of Minorca http://bit.ly/Nuralagus-rex_Press

Reconstruction & Holotype

Josep Quintana, Meike Köhler & Salvador Moyà-Solà. 2011. Nuralagus rex, gen. et sp. nov., an endemic insular giant rabbit from the Neogene of Minorca (Balearic Islands, Spain). Journal of Vertebrate Paleontology. 31 (2): 231–240. doi:10.1080/02724634.2011.550367.

http://www.wired.com/wiredscience/2012/04/repost-night-of-the-nuralagus-rex/

[Paleontology • 2007] Yanoconodon allini • A new eutriconodont mammal and evolutionary development in early mammals

Artist's representation of Yanocondon allini, a Mesozoic mammal fossil found in China. 

Courtesy Nicolle Rager Fuller, National Science Foundation.

Class Mammalia

Order Eutriconodonta  

Family Jeholodentidae (nov.)

Yanoconodon allini gen. et sp. nov.

Etymology. Yan is for the Yan mountains in Northern Hebei Province; conodon is Latin for 'cuspate tooth', a common suffix for mammalian taxonomic names; allini refers to Edgar Allin's studies on mammalian ear evolution.

Holotype. Nanjing University - Paleontology Laboratory NJU-P 06001, preserved on a slab (NJU-P06001A, shown in Fig. 1) and counter-slab (NJU-P06001B, shown in the Supplementary Information) of laminated siltstones.

Figure 1: New mammal Yanoconodon allini. a, Main part of the holotype b, Skeletal restoration

Figure 2: Relationship of Yanoconodon allini.

Analysis of all dental and skeletal characters of Yanoconodon places it as a close relative of Jeholodens, in the Jeholodentidae among eutriconodontans.

Luo, Z., Chen, P., Li, G., & Chen, M. 2007. A new eutriconodont mammal and evolutionary development in early mammals. Nature. Vol 446, doi:10.1038/nature05627

Let's hear it for the new Mesozoic mammal!: 

http://www.sciencebuzz.org/blog/lets_hear_it_for_the_new_mesozoic_mammal