Forelimb posture in Chilesaurus diegosuarezi.

 

Chilesaurus holotype cast (MACN. From Wikipedia Commons. Author: Evelyn D’Esposito)

Chilesaurus diegosuarezi is a bizarre tetanuran from the Upper Jurassic of southern Chile. Holotype specimen (SNGM-1935) consists of a nearly complete, articulated skeleton, approximately 1.6 m long. Four other partial skeletons (specimens SNGM-1936, SNGM-1937, SNGM-1938, SNGM-1888) were collected in the lower beds of Toqui Formation. For a basal tetanuran, Chilesaurus possesses a number of surprisingly plesiomorphic traits on the hindlimbs, especially in the ankle and foot, which resemble basal sauropodomorphs.

All the preserved specimens of Chilesaurus show ventrally flexed arms with the hands oriented backwards, an arrangement that closely resembles the resting posture similar described in Mei long, Sinornithoides youngi, and Albinykus baatar. However, the hindlimbs of Chilesaurus are posteriorly extended, rather than ventrally flexed. So it seems that individuals of Chilesaurus were buried quickly and fossilized almost in life position during passive activity (e.g. feeding, resting).

Cast of SNGM-1937 specimen of Chilesaurus diegosuarezi in dorsal (1), 471 lateral (2), and anterolateral view (3).

Cast of SNGM-1937 specimen of Chilesaurus diegosuarezi in dorsal (1), 471 lateral (2), and anterolateral view (3). Scale: 20 mm.

The specimen SNGM-1937 shows an angular relation in the wrist that resembles that in Deinonychus. In fact, several coelurosaurs have the same resting position as the forelimbs of Chilesaurus, with the humerus and radius-ulna in perpendicular relation or elbow flexed in an acute angle, hands under the radius-ulna, and palmar surface posterodorsal and dorsomedial oriented with respect to the main body axis. The resting posture of the forelimbs has been studied in theropod species, in relation to the acquisition of flight. It was suggested that the presence of the forelimb folded structure in advanced theropods are related with soft structures, as patagial skin and muscles, present in several maniraptoran dinosaurs.

The cojoined flexion of wrist and elbow in living birds is mainly conducted by the action of a large number of tendons located within the propatagium. Although the existence of propatagium was considered as unique to modern birds, it have also been described for coelurosaurs and Pterosauria. The preserve of a flexed forearm in Chilesaurus, may be also regarded as an indirect indicative of the presence of propatagium in this taxon.

 

References:

Nicolás R. Chimento, Federico L. Agnolin, Fernando E. Novas, Martín D. Ezcurra, Leonardo Salgado, Marcelo P. Isasi, Manuel Suárez, Rita De La Cruz, David Rubilar-Rogers & Alexander O. Vargas (2017) Forelimb posture in Chilesaurus diegosuarezi (Dinosauria, Theropoda) and its behavioral and phylogenetic implications. Ameghiniana (advance online publication) doi: 10.5710/AMGH.11.06.2017.3088

Novas, F.E., Salgado, L., Suarez, M., Agnolín, F.L., Ezcurra, M.D., Chimento, N.R., de la Cruz, R., Isasi, M.P., Vargas, A.O., and Rubilar-Rogers, D. 2015. An enigmatic plant-eating theropod from the Late Jurassic period of Chile. Nature 522: 331-334. doi:10.1038/nature14307

 

A mid-Cretaceous enantiornithine frozen in time

Overview of HPG-15-1 in right lateral view. (From Xing et al., 2017)

Overview of HPG-15-1 in right lateral view. (From Xing et al., 2017)

Amber from the Hukawng Valley in northern Myanmar, called Burmese amber, has been commercially exploited for millennia. Of the seven major deposits of amber from the Cretaceous Period, Burmese amber has probably the most diverse paleobiota, including the tail of a non-avian coelurosaurian theropod, and three juvenile enantiornithine birds. The third specimen, HPG-15-1, is the most complete fossil bird discovered in Burmese amber. It comes from the Angbamo site, and measures approximately 86 mm x 30 mm x 57 mm, and weighs 78 g. It  was encapsulated during the earliest stages of its feather production, and  plumage preserves an unusual combination of precocial and altricial features unlike any living hatchling bird.

 Details of the head in HPG-15-1. A, x-ray µCT reconstruction in left lateral view

Details of the head in HPG-15-1. A, x-ray µCT reconstruction in left lateral view (From Xing et al., 2017)

The skull was split when the amber was cut. The rostrum is preserved in one section and the neck and most of the braincase in the other. The skull is mesorostrine. A  single tooth is visible in the left premaxilla. As in Early Cretaceous enantiornithines, the premaxillary corpus is short, forming approximately one-third of the rostrum. The exoccipitals contributed to the dorsal portion of the condyle and were unfused at the time of death. The frontals articulate for most of their length with a small gap between their rostral ends as in Archaeopteryx.  The inner ear and its semicircular canals are preserved. There are at least six articulated cervical vertebrae, including the atlas and axis, preserved in articulation with the skull. The post-axial vertebrae are rectangular with large neural canals, low and caudally displaced neural spines, and a ventral keel as in many enantiornithines. The articulated skull and series of cervical vertebrae bear plumage in dense fields. The individual feathers  are dark brown in color, and appear to consist of tufts of four or more barbs. Skin is preserved as a translucent film in unfeathered regions of both the head and neck.

Microstructure and pigmentation of feathers on wing and body of HPG-15-1. Scale bars equal 1 mm in (A, C); 0.5 mm in (B, D). From Xing et al., 2017

The new specimen also preserves a partial distal wing, the distal right tibiotarsus and complete right foot as well as part of the left pes. Both skeletal material and integumentary structures from the wing’s apex are well-preserved. The plumage consists of fragments of some of the primaries, and alula feathers, some of the secondaries and coverts, and traces of contours from the wing base. The hind limbs preserve feathers and traces of skin. The absence of fusion between the tarsals indicates that the specimen is ontogenetically immature. The proportions of the pedal digits suggest an arboreal lifestyle. Plumage within the femoral and crural tracts consists of neoptile feathers with a short or absent rachis. These feathers are nearly transparent, suggesting that they were pale or white. The skin beneath the crural tract is thin and smooth. The tip of the tail clearly preserves the remains of a single large sheathed rectrix.

The slow post-natal growth results in a protracted period of vulnerability, which is reflected in the Enantiornithes by the large number of juveniles found in the fossil record, whereas young juveniles of other Cretaceous bird lineages are unknown.

 

References:

Lida Xing, Jingmai K. O’Connor, Ryan C. McKellar, Luis M. Chiappe, Kuowei Tseng, Gang Li, Ming Bai , A mid-Cretaceous enantiornithine (Aves) hatchling preserved in Burmese amber with unusual plumage, (2017), doi: 10.1016/j.gr.2017.06.001

The American incognitum and the History of Extinction Studies

 

Georges Cuvier (1769 -1832) and the painting of Charles Wilson Peale’s reconstruction of the American incognitum

Extinction is the ultimate fate of all species. More than 95% of all species that ever lived are now extinct. But prior to the 18th century, the idea that species could become extinct was not accepted. However, as the new science of paleontology began bringing its first major discoveries to light, researchers began to wonder if the large vertebrate fossils of strange creatures unearthed by the Enlightenment explorers were indeed the remains of extinct species.

In 1739, French soldiers under the command of Baron Charles le Moyne de Lougueuil recovered a tusk, femur, and three curious molar teeth from Big Bone Lick, Kentucky, a place known in several American Indian narratives. Lougueuil sent these specimens to the Cabinet du Roi (Royal Cabinet of Curiosities) in Paris. In 1762, Louis Jean-Marie Daubenton, a zoologist at the Jardin du Roi concluded that the femur and tusk from the Longueuil’s collection were those of a large elephant, the “Siberian Mammoth,” but the three molars came from a gigantic hippopotamus.

Molar collected at Big Bone Lick in 1739 and described in Paris in 1756. (Georges Cuvier, Recherches sur les ossemens fossiles)

By the early 18 century it was inconceivable for many researchers that a species could be vanished. Naturalist Georges-Louis Leclerc de Buffon, wrote in 1749 about the extinction of marine invertebrates, but he adopted Daubenton’s view that the Siberian mammoth and the animal of the Ohio, known as the American incognitum, were both northern forms of the extant elephant rather than a vanished species. British anatomist William Hunter was the first to speculate that these remains might be from an extinct species. In 1799, the discovery of an American incognitum femur from Quaternary deposits in the Hudson River Valley led to excavations organized by Charles Wilson Peale. In 1801, the excavations resulted in the recovery of an almost complete skeleton. Peale reconstructed the skeleton with help from the American anatomist Caspar Wistar, and the displayed the mounted skeleton in public in December of that year.

In 1806 Georges Cuvier resolved the controversy about the  American incognitum demonstrating that both the Siberian mammoth and the “animal de l’Ohio” were elephants, but of different species. He described the Ohio elephant as a mastodon and he reached the conclusion that probably represented an extinct species. Cuvier was also the first to suggested that periodic “revolutions” or catastrophes had befallen the Earth and wiped out a number of species. But, under the influence of Lyell’s uniformitarianism, Cuvier’s ideas were rejected as “poor science”. The modern study of mass extinction did not begin until the middle of the twentieth century. One of the most popular of that time was “Revolutions in the history of life” written by Norman Newell in 1967.

 

References:

Macleod, N. The geological extinction record: History, data, biases, and testing. Geol. Soc. Am. Spec. Pap. 505, (2014), DOI: 10.1130/2014.2505(01)​

Marshall, Charles R., Five palaeobiological laws needed to understand the evolution of the living biota, Nature Ecology & Evolution 1, 0165 (2017), DOI: 10.1038/s41559-017-0165 .

Terrestrial floras at the Triassic-Jurassic Boundary in Europe.

Proportions of range-through diversities of higher taxonomic categories of microfloral elements over the Middle Triassic–Early Jurassic interval (From Barbacka et al., 2017)

Over the last 3 decades, mass extinction events  have become the subject of increasingly detailed and multidisciplinary investigations. Most of those events are associated with global warming and proximal killers such as marine anoxia. Volcanogenic-atmospheric kill mechanisms include ocean acidification, toxic metal poisoning, acid rain, increased UV-B radiation, volcanic darkness, cooling and photosynthetic shutdown. The mass extinction at the Triassic-Jurassic Boundary (TJB) has been linked to the eruption of the Central Atlantic Magmatic Province (CAMP), a large igneous province emplaced during the initial rifting of Pangea. Another theory is that a huge impact was the trigger of the extinction event. At least two craters impact were reported by the end of the Triassic. The Manicouagan Impact crater in the Côte-Nord region of Québec, Canada was caused by the impact of a 5km diameter asteroid, and it was suggested that could be part of a multiple impact event which also formed the Rochechouart crater in France, Saint Martin crater in Canada, Obolon crater in Ukraine, and the Red Wing crater in USA (Spray et al., 1998).

Photographs of some Rhaetian–Hettangian spores and pollen from the Danish Basin (From Lindström, 2015)

Most mammal-like reptiles and large amphibians disappeared, as well as early dinosaur groups. In the oceans, this event eliminated conodonts and nearly annihilated corals, ammonites, brachiopods and bivalves. In the Southern Hemisphere, the vegetation turnover consisted in the replacement to Alisporites (corystosperm)-dominated assemblage to a Classopollis (cheirolepidiacean)-dominated one. But there was no mass extinction of European terrestrial plants during the TJB. The majority of genera and a high percentage of species still existed in its later stages, and replacement seems to have been local, explainable as a typical reaction to an environmental disturbance. In Greenland, for example, the replacement of Triassic wide-leaved forms with Jurassic narrow-leaved forms was linked to the reaction of plants to increased wildfire. In Sweden, wildfire in the late Rhaetian and early Hettangian caused large-scale burning of conifer forests and ferns, and the appearance of new swampy vegetation. In Austria and the United Kingdom, conifers and seed ferns were replaced by ferns, club mosses and liverworts. In Hungary, there was a high spike of ferns and conifers at the TJB, followed by a sudden decrease in the number of ferns along with an increasing share of swamp-inhabiting conifers.

Although certain taxa/families indeed became extinct by the end of the Triassic (e.g. Peltaspermales), the floral changes across Europe were rather a consequence of local changes in topography.

References:

Maria Barbacka, Grzegorz Pacyna, Ádam T. Kocsis, Agata Jarzynka, Jadwiga Ziaja, Emese Bodor , Changes in terrestrial floras at the TriassicJurassic Boundary in Europe, Palaeogeography, Palaeoclimatology, Palaeoecology (2017), doi: 10.1016/j.palaeo.2017.05.024

S. Lindström, Palynofloral patterns of terrestrial ecosystem change during the end-Triassic event — a review, Geol. Mag., 1–23 (2015) https://doi.org/10.1017/S0016756815000552

Van de Schootbrugge, B., Quan, T.M., Lindström, S., Püttmann, W., Heunisch, C., Pross, J., Fiebig, J., Petschick, R., Röhling, H.-G., Richoz, S., Rosenthal, Y., Falkowski, P. G., 2009. Floral changes across the Triassic/Jurassic boundary linked to flood basalt volcanism. Nat. Geosci. 2, 589–594. doi: 10.1038/NGEO577.

N.R. Bonis, W.M. Kürschner, Vegetation history, diversity patterns, and climate change across the Triassic/Jurassic boundary, Paleobiology, 8 (2) (2012), pp. 240–264 https://doi.org/10.1666/09071.1

Zuul, the Gatekeeper

Skull of Zuul (Photograph: Brian Boyle/Royal Ontario Museum)

The Ankylosauria is a group of herbivorous, quadrupedal, armoured dinosaurs subdivided in two major clades, the Ankylosauridae and the Nodosauridae. Zuul crurivastator, from the Coal Ridge Member of the Judith River Formation of northern Montana, is the most complete ankylosaurid ever found in North America. The generic name refers to Zuul the Gatekeeper of Gozer (from the 1984 film Ghostbusters), and the species epithet combines crus (Latin) for shin or shank, and vastator (Latin) for destroyer, in reference to the sledgehammer-like tail club. The extraordinary preservation of abundant soft tissue in the skeleton, including in situ osteoderms and skin impressions make this specimen an important reference for understanding the evolution of dermal and epidermal structures in this clade. Until the discovery of Zuul, Laramidian ankylosaurin specimens were primarily assigned to three taxa: Euoplocephalus tutus and Ankylosaurus magniventris from northern Laramidia, and Nodocephalosaurus kirtlandensis from southern Laramidia.

The holotype (ROM 75860)  is a partial skeleton consisting of a nearly complete cranium, and a partially articulated postcranium. It is estimated to be over 6 metres long, and it would have weighed approximately 2500 kg. It has been dated to approximately 75 million years ago, and it was discovered accidentally on 16 May 2014 during overburden removal for a scattered tyrannosaurid skeleton, when a skid-steer loader encountered the tail club knob.

Overview of the tail of Zuul crurivastator in dorsal view, with insets of detailed anatomy (From Arbour and Evans, 2017)

The skull is almost complete, missing only the tip of the right quadratojugal horn and the ventral edge of the vomers, and is the largest ankylosaurine skull recovered from Laramidia. The skull is relatively flat dorsally, and had an elaborate ornamentation across the snout. The squamosal horns are robust and pyramid-shaped, and the quadratojugal horns had a sharp, posteriorly offset apex.

The tail club (including the 13 caudal vertebrae in the handle and the knob) is at least 210 cm long. Osteoderms are preserved not only in the anterior, flexible portion of the tail but also along the tail club handle. The first three pairs of caudal osteoderms are covered with a black film, that probably represent preserved keratin, and is similar to the texture observed at the base of bovid horn sheaths.

The discovery of Zuul fills a gap in the ankylosaurine record and further highlights that Laramidian ankylosaurines were undergoing rapid evolutionary rates and stratigraphic turnover as observed for Laramidian ceratopsids, hadrosaurids, pachycephalosaurids and tyrannosaurids.

References:

Arbour V. M., Evans D. C., (2017), A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation , Royal Society Open Science, rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.161086

Arbour, V. M.; Currie, P. J. (2015). “Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs”. Journal of Systematic Palaeontology: 1–60. doi: 10.1080/14772019.2015.1059985

Jianianhualong and the evolution of feathers.

Jianianhualong tengi holotype (From Xu, X. et al., 2017)

In recent years, several discovered fossils of theropods and early birds have filled the morphological, functional, and temporal gaps along the line to modern birds. Most of these fossils are from the Jehol Biota of northeastern China, dated between approximately 130.7 and 120 million years ago. Among them are many fossils of troodontids, which are considered as the closest relatives of birds. Previous reported troodontid species include Mei long, Sinovenator changii, Sinusonasus magnodens and Jinfengopteryx elegans. Now a new troodontid, Jianianhualong tengi gen. et sp. nov., has anatomical features that shed light on troodontid character evolution.

The holotype (DLXH 1218) is a nearly complete skeleton with associated feathers, and is inferred to be an adult. It is estimated to be 112 cm in total skeletal body length with a fully reconstructed tail, and its body mass is estimated to be 2.4 kg, similar to most other Jehol troodontids, such as Sinovenator. The skull and mandible are in general well preserved, and  has a relatively short snout and highly expanded skull roof. There are probably 21 maxillary teeth and 25 dentary teeth on each side of the jaw. The vertebral column is nearly completely represented and  the tail is 54 cm long. The furcula is poorly preserved, and the humerus is 70% of femoral length. The manus is typical of maniraptoran theropods, and measures 112 mm in length. The pelvis is in general similar to those of basal troodontids, with a proportionally small ilium, a posteroventrally oriented pubis, and a short ischium. A phylogenetic analysis places Jianianhualong in an intermediate position together with several species between the basalmost and derived troodontids.

Plumage of Jianianhualong tengi (Adapted from Xu, X.  et al, 2017)

The tail frond of Jianianhualong preserves an asymmetrical feather, the first example of feather asymmetry in troodontids. Feathers were once considered to be unique avialan structures. Since the discovery of the feathered Sinosauropteryx in 1996, numerous specimens of most theropod groups and even three ornithischian groups preserving feathers have been recovered from the Jurassic and Cretaceous beds of China, Russia, Germany, and Canada. These feathers fall into several major morphotypes, ranging from monofilamentous feathers to highly complex flight feathers.

Evidence indicates that the earliest feathers evolved in non-flying dinosaurs for display or thermoregulation, and later were co-opted into flight structures with the evolution of asymmetrical pennaceous feathers in Paraves, therefore, the discovery of tail feathers with asymmetrical vanes in a troodontid theropod indicates that feather asymmetry was ancestral to Paraves.

 

 

References:

Xu, X. et al. Mosaic evolution in an asymmetrically feathered troodontid dinosaur with transitional features. Nat. Commun. 8, 14972 doi: 10.1038/ncomms14972 (2017).

Xu, X. et al. An integrative approach to understanding bird origins, Science, Vol. 346 no. 6215 (2014). DOI: 10.1126/science.1253293

Dinosaur Island

 

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Batman #1, New 52

In Batman #1 in the New 52, we see a giant animatronic dinosaur kept in the Batcave as a trophy. The T. rex is a reminder from an early adventure on Dinosaur Island (Batman #35, from June 1946). In that story, Murray Wilson Hart, a wealthy industrialist creates an amusement park named Dinosaur Island, filled with robot replicas of dinosaurs and robotic cavemen, but a criminal takes control of the mechanical dinosaurs and attacks Batman and Robin. Eventually, the dynamic duo defeat the criminal and Batman take the T. rex as a souvenier.

A second and definitive version of Dinosaur Island appeared in the Spring 1960 issue of Star-Spangled War Stories #90. Based on The Land That Time Forgot by Edgar Rice Burroughs, the saga follows a group of American soldiers, stranded on an uncharted island during the Pacific War which they discover is populated by dinosaurs. The original novel was set on World War I and is a reminder of Jules Verne’s novel Journey to the Center of the Earth, and Arthur Conan Doyle’ s The Lost World.

Cover of The War that Time Forgot by Ross Andru & Mike Esposito

Almost three decades before Verne’s Journey to the Center of the Earth, Rodolphe Töpffer (1799- 1846) published a peculiar geological tale. Töpffer was a Swiss author considered the first comics artist.  In Journey to the Center of the Earth (1864), Jules Verne incorporated the knowledge of the time. Verne was inspired by Charles Lyell’s Geological Evidences of the Antiquity of Man and Lyell’s earlier ground-breaking work Principles of Geology.

Arthur Conan Doyle began to write The Lost World in 1911. One year later it was published in book form by Hoddar and Stoughton. By that time he already was one of the most popular author around the globe, thanks to his most iconic creation, Sherlock Holmes. Probably, one of the most influential works in Doyle’s novel was “Extinct Animals” by Ray Lankester,  Director of the Natural History Museum. The Lost World has much in common with Journey to the Centre of the Earth, and has contributed significantly to the fascination with dinosaurs and pterodactyls. Even more, the first full-length science fiction film was based on Conan Doyle’s novel.

 

References:

Conan Doyle, A. 1912. The Lost World. Hodder & Stoughton, London.

Verne, J. G. 1864. Voyage au centre de la Terre. Pierre Jules Hetzel, Paris.

Edgar Rice Burroughs, The Land That Time Forgot,  Blue Book Magazine, 1918

Batman #35, DC Comics, 1946

Star-Spangled War Stories #90, DC Comics, 1960

 

 

Solving the mystery of Megatherium diet.

Megatherium americanum, MACN.

Around 10,000 years ago, Argentina was home of numerous species of giant Xenarthrans, giant ground sloths (relative to tree sloth) and glyptodontids (relative to tiny extant armadillo). Sloths, characteristic of the mammal fauna of the Pleistocene of South America, show a great diversity with more than 80 genera, grouped in four families: Megatheriidae, Megalonychidae, Nothrotheriidae and Mylodontidae.

For more than a century different hypotheses on the dietary preferences of giant ground sloths have been proposed. In 1860, Owen gave an extensive explanations about their possible diet and behavior. He based his conclusions on the morphology of the skull, combined with peculiarities of the rest of the skeleton, but always by analogy with living tree sloth. He wrote: “Guided by the general rule that animals having the same kind of dentition have the same kind of food, I conclude that the Megatherium must have subsisted, like the Sloths, on the foliage of tree…”. In 1926, Angel Cabrera discussed the diet of Megatherium, rejecting some theories on myrmecophagy or insectivory, and agreed with Owen’s statements about a folivorous diet.

Megatherium americanum lower right tooth series. Scale bar: 5 cm (From M.S. Bargo and S.F. Vizcaíno, 2008)

The dietary preferences of extinct mammals can usually be evaluated through their tooth morphology, but the application of stable isotopes on fossil bones has yielded very important information to solve debates about the diet of extinct large mammal groups, by comparing the carbon and nitrogen isotopic composition of their bone collagen with those of coeval herbivorous and carnivorous taxa. Another isotopic approach is to mesure the difference between the carbon isotopic abundances of the collagen and the carbonate fractions of skeletal tissues. An animal with a herbivorous diet, exhibits significantly larger differences than a carnivore. The values measured on bone collagen from Megatherium, clearly fall in the same range as the large herbivores such as the equid Hippidion, the notoungulate Toxodon and the liptoptern Macrauchenia, for which there is no doubt about their herbivorous diet. Therefore, the hypotheses of insectivory or carnivory for these extinct mammals are not supported by the isotopic data.

 

References:

Hervé Bocherens et al. Isotopic insight on paleodiet of extinct Pleistocene megafaunal Xenarthrans from Argentina, Gondwana Research (2017). DOI: 10.1016/j.gr.2017.04.003

Bargo, M.S., Vizcaíno, S.F., 2008. Paleobiology of Pleistocene ground sloths (Xenarthra, Tardigrada): biomechanics, morphogeometry and ecomorphology applied to the masticatory apparatus. Ameghiniana 45: 175-196

Introducing Zhongjianosaurus.

 

Photograph of Zhongjianosaurus yangi holotype (From Xu & Qin, 2017).

Dromaeosaurids are a group of carnivorous theropods, popularly known as “raptors”. Most of them were small animals, ranging from about 0.7 metres in length to over 7 metres. They had a relatively large skull with a narrow snout and the forward-facing eyes typical of a predator. They also had serrated teeth, and their arms were long with large hands, a semi-lunate carpal, with three long fingers that ended in big claws. The earliest known representatives are from the Lower Cretaceous Jehol Group of western Liaoning, China. The most recent described dromaeosaurid is Zhongjianosaurus yangi. The new taxon was named in honor of  Yang Zhongjian, who is the founder of vertebrate paleontology in China.

The Early Cretaceous Jehol dromaeosaurids not only display a great size disparity, but also show a continuous size spectrum. Zhongjianosaurus represents the ninth dromaeosaurid species reported from the Jehol Biota. It was first reported in 2009, and is notable for its small size (about 25 cm tall), compact body, and extremely long legs.

Zhongjianosaurus yangi holotype. A. right scapulocoracoid in lateral view and furcula in posterior view; B. right humerus in anterior view; C. left ulna and radius in lateral view; D. ‘semilunate’ carpal, metacarpals II and III in ventral view and phalanges II-1 and -2 in lateral view; scale bars equal 5 mm (From Xu & Qin, 2017)

The holotype is an adult individual distinguishable from other microraptorines in possessing many unique features, most of them are present in the forelimbs. For example, the humerus has a strongly offset humeral head, a large fenestra near the proximal end, and a large ball-like ulnar condyle. Zhongjianosaurus also displays several other features which are absent in other Jehol dromaeosaurids. For instance, the uncinate processes are proportionally long and fused to the dorsal ribs, the caudal vertebral transitional point is located anteriorly, and the pes exhibits a full arctometatarsalian condition.

The coexistence of several closely related Jehol dromaeosaurids can be interpreted as niche differentiation. Tianyuraptor have limb proportions and dental morphologies typical of non-avialan carnivorous theropods, suggesting that they were ground-living cursorial predators, meanwhile Microraptor are more likely to have been arboreal or even gliding animals.

References:

Xu X , Qin Z C, 2017, in press. A new tiny dromaeosaurid dinosaur from the Lower Cretaceous Jehol Group of western Liaoning and niche differentiation among the Jehol dromaeosaurids. Vertebrata PalAsiatica

Xu X, 2002. Deinonychosaurian fossils from the Jehol Group of western Liaoning and the coelurosaurian evolution. Ph.D thesis, Beijing: Chinese Academy of Sciences. 1–322

Tilly Edinger vs. the nazis.

Tilly Edinger (Photo,Museum of Comparative Zoology, Harvard University, Cambridge, MA)

“Tilly” Edinger was born on November 13, 1897 in Frankfurt, Germany. She was the youngest daughter of the eminent neurologist Ludwig Edinger and Dora Goldschmidt, a leading social advocate and activist. In 1914, her father became the first Chair of Neurology in Germany, at the newly founded University of Frankfurt. He encouraged her to take science courses at the Universities of Heidelberg, Frankfurt, and Munich. Her research at Frankfurt was directed by Fritz Drevermann, director of the Senckenberg Museum. After her graduation in 1921, Edinger worked as an assistant in the Geological Institute of Frankfurt University. In 1927, she was  named Curator of Fossil Vertebrates at the Senckenberg. At that time, she had no colleagues in vertebrate paleontology in Frankfurt with the exception of Drevermann. She described the positive and negative aspects of that environment in a letter addressed to A. S. Romer: “all fossil vertebrates [at the Senckenberg Museum] are entirely at my disposition: nobody else is interested in them . . . On the other hand, this means that I am almost autodidact”. 

Among her early projects were descriptions the endocranial casts of Mesozoic marine reptiles, pterosaurs and Archaeopteryx.  In 1929,  she published Die fossilen Gehirne (Fossil Brains), the book that established Edinger’s membership in the German and international paleontological communities. This work would serve as the major scientific support for her wartime immigration to the United States.

Senckenberg Naturmuseum (Senckenberg Museum of Natural History)

After the death of German President Paul von Hindenburg on August 2, 1934, Chancellor Adolf Hitler became Führer of Germany. In the months following Hitler’s ascension to the power, the Nazis took control of all of the nation institutions. The universities were not excepted. Soon, Jewish professors were dismissed, arrested, or simply disappeared. At the time, Tilly Edinger was working  as curator of fossil vertebrates at the Senckenberg Museum of Natural History in Frankfurt, so the influence of the new rules on her professional life was slower than on many other persons of Jewish descent because the Senckenberg was a private institution, and her position there was unsalaried. She continued working at the Museum thanks to protective actions of Rudolf Richter, the invertebrate paleontologist who had succeeded Drevermann at the Senckenberg.

Although urged by friends to leave the country, she chose to stay, as did their brother, Friedrich, who later (1942) became a victim of the Holocaust. But, on the night of 9–10 November 1938, her paleontological career in Germany ended.  Nearly 100 Jews were killed and thousands were imprisoned in the infamous “Kristallnacht” (Night of the Broken Glass). Decided to leave Germany as soon as possible, she wrote to her childhood classmate Lucie Jessner, a psychiatrist who had immigrated first to Switzerland in 1933 and then to the United States in early 1938. Jessner contacted the eminent Harvard paleontologist Alfred S. Romer (1884–1973), writing: “My friend—Dr. Tilly Edinger, paleontologist in Frankfurt am Main, Germany—wants me to ask you about different matters, very important for her. She believes you might know her name by several of her papers and you might be friendly enough to give me the opportunity to speak with you”

Interior of Berlin’s Fasanenstrasse Synagogue, opened in 1912, after it was set on fire during Kristallnacht on November 9, 1938

With the positive response from Romer, Edinger applied for an American visa at the American Consulate in Stuttgart on 1 August 1938. Forced to look for another, short-term solution, she contacted Philipp Schwartz, a former pathology professor at the University of Frankfurt who had established the Notgemeinschaft Deutscher Wissenschaftler im Ausland (Emergency Association of German Scientists in Exile), a society dedicated to helping scientific refugees from Nazi Germany. Waiting for a solution, she wrote to Rudolf Richter to thank him for his supportive testimonial. She shared her conviction that “One way (England) or the other (United States), fossil vertebrates will save me”. 

Thanks to her pioneering works and the contacts she made from a previous trip to London in 1926, Edinger emigrated to England in May 1939. She started working at the British Museum of Natural History, alternately translating texts and working on her own paleoneurological projects. She described her life in London as considerably freer than in Germany: “It sounds funny, to one who was ‘at home’ not allowed to enter even an open museum, or a cinema, or a café, to apply the word ‘restrictions’ anywhere in the beautifully free life I am leading here”

Tilly Edinger and colleagues at the Museum of Comparative Zoology. Sitting left to right: Tilly Edinger, Harry B. Whittington, Ruth Norton, Alfred S. Romer, Nelda Wright, and Richard van Frank. Standing left to right: Arnold D. Lewis, Ernest E.Williams, Bryan Patterson, Stanley J. Olsen, and Donald Baird. (Photo: David Roberts, from Buchholtz, 2001)

In 1940, with the support of Alfred S. Romer, she moved to Massachusetts to take a position at the Harvard Museum of Comparative Zoology. By the early 1950s, she was not only the major contributor to the field of paleoneurology but also the mentor to a younger generation that was following in her footsteps. She received several honorary doctorates for her achievements, including Wellesley College (1950), the University of Giessen (1957), and the University of Frankfurt  (1964). She was elected president of SVP in 1963. Her last book: “Paleoneurology 1804-1966. An annotated bibliography”, was completed by several of her colleagues and is considered the necessary starting point for any project in paleoneurology.

 

References:

Buchholtz, Emily A.; Seyfarth, Ernst-August (August 2001), “The Study of “Fossil Brains”: Tilly Edinger (1897–1967) and the Beginnings of Paleoneurology”, Bioscience 51 (8)

Susan Turner, Cynthia V. Burek and Richard T. J. Moody, Forgotten women in an extinct saurian (man’s) world, Geological Society, London, Special Publications 2010, v. 343, p. 111-153