An early juvenile enantiornithine specimen from the Early Cretaceous of Spain

The slab and counterslab of MPCM-LH-26189

Mesozoic remains of juvenile birds are rare. To date, the only records are from the Early Cretaceous of China and Spain, from the mid-Cretaceous of  Myanmar, and from the Late Cretaceous of Argentina and Mongolia. The most recent finding from the Early Cretaceous of Las Hoyas, Spain, provide an insight into the osteogenesis of the Enantiornithes, the most abundant clade of Mesozoic birds. Previous records of Enantiornithes from the Las Hoyas fossil site include: Eoalulavis hoyasi, Concornis lacustris, and Iberomesornis romerali.

The latest specimen, MPCM-LH-26189, a nearly complete and largely articulated skeleton (only the feet, most of its hands, and the tip of the tail are missing), is very small. The specimen died around the time of birth, a crucial moment to study the osteogenesis in birds. The skull, is partially crushed, and is large compared to the body size. The braincase is fractured. The frontals and the parietals form a uniformly curved cranial vault. The cerebrocast shows a very slight inflation, suggesting that the cerebral anatomy of MPCM-LH-26189 falls in between that of the Archaeopteryx, and the putative basal ornithurine Cerebavis, whose telencephalic expansion is close to most extant birds. The cervical series is composed of 9 vertebrae. There are 10  thoracic vertebrae, and the sacrum appears to be composed of 5–6 vertebrae. The prezygapophyses of the mid-thoracic vertebrae extend beyond the cranial articular surface. The thoracic ribs are joint to the thoracic vertebrae. The two coracoids, the furcula, and three sternal ossifications are preserved. The furcula is Y-shapped. Both humeri, ulnae, and radii are also preserved.

Reconstruction of MPCM-LH-26189 by Raúl Martín

The osteohistological analysis of the left humerus shows a dense pattern of longitudinal grooves. Those grooves correspond to primary cavities, which open onto the surface of the cortex in young and fast-growing bone. The shaft of the tibia and radius show very-thin cortices. In addition,  the primary nature of the vascularisation, the round shape of the osteocytes lacunae and the uneven peripheral margin of the medullary cavity (with no endosteal bone), strongly suggests that the bone was actively growing when the bird died.

Enantiornithines show a mosaic of characters, reflecting their intermediate phylogenetic position between the basal-pygostylians and modern bird. In this clade, the sternum adopts an elaborate morphology, and in adult Enantiornithes, no more than eight free caudal vertebrae precede the pygostyle. The differences observed in the ossification of the sternum and the number of free caudal vertebrae in MPCM-LH-26189, when it compared to other juvenile enantiornithines, reveal a clade-wide asynchrony in the sequence of ossification of the sternum and tail, suggesting that the developmental strategies of these basal birds may have been more diverse than previously thought.


Fabien Knoll, et al., “A diminutive perinate European Enantiornithes reveals an asynchronous ossification pattern in early birds,” Nature Communications, volume 9, Article number: 937 (2018) doi:10.1038/s41467-018-03295-9

Chiappe, L. M., Ji, S. & Ji, Q. Juvenile birds from the Early Cretaceous of China: implications for enantiornithine ontogeny. Am. Mus. Novit. 3594, 1–46 (2007).




Forgotten women of Paleontology: Carlotta Joaquina Maury

Carlotta Joaquina Maury (January 6, 1874 – January 3, 1938)

In the 18th and 19th centuries women’s access to science was limited. Early female scientists were often born into influential families, like Grace Milne, the eldest child of Louis Falconer and sister of the eminent botanist and palaeontologist, Hugh Falconer. Unfortunately, their contribution has not been widely recognised by the public or academic researchers. Women collected fossils and mineral specimens, and were allowed to attend scientific lectures, but they were barred from membership in scientific societies. By the 1880, in the United States, geology was a marginal subject in the curricula of the early women’s colleges until an intense programme was started at Bryn Mawr College, a decade later.

Carlotta Joaquina Maury was born on January 6, 1874 in Hastings-on-Hudson, New York. She was the youngest  sister of astronomer Antonia Maury, who worked at the Harvard College Observatory as one of the so-called Harvard Computers. She was also the granddaughter of John William Draper and a niece of Henry Draper, both pioneering astronomers. Maury maternal grandmother was Antonia Coetana de Paiva Pereira, member of Portuguese nobility serving at the court of Emperor Dom Pedro I of Brazil, a connection which had and important influence on her career.

Harvard Computers at work, including Henrietta Swan Leavitt (1868–1921), Annie Jump Cannon (1863–1941), Williamina Fleming (1857–1911), and Antonia Maury (1866–1952).

She was educated at Radcliffe College from 1891 to 1894. Influenced by Elizabeth Agassiz, co-founder and first president of Radcliffe College, Maury attended Cornell University, where she obtained a PhD in 1902, making her one of the first women to receive her PhD in paleontology. Her mentor was Gilbert Harris, who founded the scientific journal Bulletins of American Paleontology.

Before completing her PhD, she spent a year at the Sorbonne. After teaching in several universities, she investigated microfossils in drilling samples along the Texas and Louisiana coasts and was given an official title as a paleontologist for the Louisiana Geological Survey. In 1910, Maury was recruited to be the paleontologist for oil geologist A.C. Veatch’s year-long geological expedition to Venezuela, a study funded by the General Asphalt Company of Philadelphia. Her discovery in Trinidad of Old Eocene beds with fossils faunas related to those of Alabama and the Pernambuco region of Brazil was the first finding of Old Eocene in the entire Caribbean and northern South America region.

Carlotta Maury at the Palaeontology Laboratory in Cornell. (From Arnold, 2009)

After a short break for teaching at Huguenot College in Wellington, South Africa, Maury returned to the Caribbean in 1916 as the leader of the “Maury Expedition” to the Dominican Republic, during a period of violent political upheaval on the island. The results  – type sections and descriptions of fossils, including more than 400 new species – are the foundation for the international Dominican Republic Project, a multi-disciplinary research effort that aims s to understand evolutionary change in the Caribbean from the Miocene era to the present day.

Her reputation for being extremely efficient and energetic helped her to defy the prejudice against professional women at the time. She was a consulting palaeontologist and stratigrapher to Royal Dutch Shell’s Venezuela Division for more than 20 year, and one of the official palaeontologists with the Geological and Mineralogical Service of Brazil. In 1925, she published “Fosseis Terciarios do Brazil with Descripção de Nova Cretaceas Forms” where she described numerous species of mollusks from the northeastern coast, performing the stratigraphic correlation of these faunas with similar faunas of the Caribbean and Gulf of Mexico.

C. Maury in 1916, Dominican Republic.

Maury was fellow of the Geological Society of America, and of the American Geographical Society. During the last decade of her life, she dedicated to publishing her consulting reports. Her last report about the Pliocene fossils of Acre, Brazil, appeared in 1937, shortly before her death. The same year she was elected member of the Brazilian Academy of Sciences.
Carlotta Maury died January 3, 1938 in Yonkers, New York.


Lois Arnold (2009), The Education and Career of Carlotta J. Maury: Part 1., Earth Sciences History 28.2 (2009): 219-244 

M. R. S. Creese (2007), Fossil hunters, a cave explorer and a rock analyst: notes on some early women contributors to geology, Geological Society, London, Special Publications, 281, 39-49.

Burek, C.V. and B. Higgs, eds. (2007) The Role of Women in the History of Geology (London: Geological Society).


Volcanism, the Chicxulub impact and the K-Pg event.

The Deccan traps

It was the best of times. It was the worst of times. The end of the Mesozoic era at ca. 66 million years ago (Ma) is marked by one of the most severe biotic crisis in Earth’s history: the Cretaceous-Paleogene (K-Pg) mass extinction. During the event, three-quarters of the plant and animal species on Earth disappeared, including non-avian dinosaurs, other vertebrates, marine reptiles and invertebrates, planktonic foraminifera and ammonites. Marine ecosystems lost about half of their species while freshwater environments shows low extinction rates, about 10% to 22% of genera.

Two events were linked to this mass extinction: the eruption of the Deccan Traps large igneous province, and the Chicxulub meteorite impact. Early work speculated that the Chicxulub impact triggered large-scale mantle melting and initiated the Deccan flood basalt eruption. Precise dating of both, the impact and the flood basalts, show that the earliest eruptions of the Deccan Traps predate the impact. But, the Chicxulub impact, and the enormous Wai Subgroup lava flows of the Deccan Traps continental flood basalts appear to have occurred very close together in time. Recent studies suggest a possible association between the Chicxulub impact and variations in the progression of Deccan Traps eruptions. Seismic modeling indicates that the impact could have generated seismic energy densities of order 0.1–1.0 J/m3 throughout the upper ∼200 km of Earth’s mantle, sufficient to trigger volcanic eruptions worldwide.

Gravity anomaly map of the Chicxulub impact structure (From Wikimedia Commons)

The oceanic crust records the history of temporal variations in seafloor magmatism continuously and at high resolution through geologic time. Around the time of the Chicxulub impact, 23,000 to 230,000 cubic miles of magma erupted out of the mid-ocean ridges, all over the globe. One of the largest eruptive events in Earth’s history. This pulse of global marine volcanism played an important role in the environmental crisis at the end of the Cretaceous, through magmatism by extruding large volumes of basalt and releasing volcanic gases or through enhanced hydrothermal venting driven by magmatic intrusion. Marine volcanism also provides a potential source of oceanic acidification.

The Chicxulub impact released an estimated energy equivalent of 100 teratonnes of TNT and produced high concentrations of dust, soot, and sulfate aerosols in the atmosphere. The decrease of sunlight caused a drastic short-term global reduction in temperature (15 °C on a global average, 11 °C over the ocean, and 28 °C over land). While the surface and lower atmosphere cooled, the tropopause became much warmer, eliminate the tropical cold trap and allow water vapor mixing ratios to increase to well over 1,000 ppmv in the stratosphere. Those events accelerated the destruction of the ozone layer. During this period, UV light was able to reach the surface at highly elevated and harmful levels.



Joseph S. Byrnes and Leif Karlstrom, Anomalous K-Pg–aged seafloor attributed to impact-induced mid-ocean ridge magmatism, Sci Adv 4 (2), eaao2994, DOI: 10.1126/sciadv.aao2994

Charles G. Bardeen, Rolando R. Garcia, Owen B. Toon, and Andrew J. Conley, On transient climate change at the Cretaceous−Paleogene boundary due to atmospheric soot injections, PNAS 2017 ; published ahead of print August 21, 2017 DOI: 10.1073/pnas.1708980114

The oldest Archaeopteryx

Overview of the skeleton of the new Archaeopteryx specimen (From Rauhut et al., 2018)

The Archaeopteryx story began in  the summer of 1861, two years after the publication of the first edition of Darwin’s Origin of Species, when workers in a limestone quarry in Germany discovered the impression of a single 145-million-year-old feather. On August 15, 1861, German paleontologist Hermann von Meyer wrote a letter to the editor of the journal Neues Jahrbuch für Mineralogie, Geologie und Palaeontologie, where he made the first description of the fossil. On on September 30, 1861, he wrote a new letter:  “I have inspected the feather from Solenhofen closely from all directions, and that I have come to the conclusion that this is a veritable fossilisation in the lithographic stone that fully corresponds with a birds’ feather. I heard from Mr. Obergerichtsrath Witte, that the almost complete skeleton of a feather-clad animals had been found in the lithographic stone. It is reported to show many differences with living birds. I will publish a report of the feather I inspected, along with a detailed illustration. As a denomination for the animal I consider Archaeopteryx lithographica to be a fitting name”. 

The near complete fossil skeleton found in a Langenaltheim quarry near Solnhofen – with clear impressions of wing and tail feathers –  was examined by Andreas Wagner, director of the Paleontology Collection of the State of Bavaria in Germany. He reached the conclusion that the fossil was a reptile, and gave it the name Griphosaurus. He wrote: “Darwin and his adherents will probably employ the new discovery as an exceedingly welcome occurrence for the justification of their strange views upon the transformations of animals.” In later editions of The Origin of Species, Darwin indeed mention the Archaeopteryx“That strange bird, Archaeopteryx, with a long lizardlike tail, bearing a pair of feathers on each joint, and with its wings furnished with two free claws . . . Hardly any recent discovery shows more forcibly than this, how little we as yet know of the former inhabitants of the world.”

Archaeopteryx lithographica, Archaeopterygidae, Replica of the London specimen; Staatliches Museum für Naturkunde Karlsruhe, Germany. From Wikimedia Commons

Over the years, eleven Archaeopteryx specimens has being recovered. The new specimen from the village of Schamhaupten, east-central Bavaria is the oldest representative of the genus (earliest Tithonian). The new specimen was discovered by a private collector. Although it was registered as German national cultural heritage, which guarantees its permanent availability, the specimen remains in private hands (Datenbank National Wertvollen Kulturgutes number DNWK 02924).

The new specimen is preserved as a largely articulated skeleton. However, the shoulder girdles and arms, as well as the skull have been slightly dislocated from their original positions, but the forelimbs remain in articulation. The skull is triangular in lateral outline and has approximately 56 mm long. The orbit is the largest cranial opening (approximately 16 mm long), and the lateral temporal fenestra is collapsed. There are probably four tooth positions in the premaxilla, nine in the maxilla and 13 in the dentary.

Articulated dorsal vertebral column of the new Archaeopteryx, including dorsal ribs and gastralia. Scale bar is 10 mm. (From Rauhut et al., 2018)

The postcranial skeleton was affected by breakage and loss of elements prior to or at the time of discovery. The sacral region, and the caudal vertebrae are very poorly preserved. Several dorsal ribs are preserved, and gastralia ribs are present in the thoracic region and the abdominal region. The shoulder girdle comprises the scapula, coracoid and furcula. Both humeri are poorly preserved. Parts of the phalanges are, largely poorly, preserved, and they do not show much detail. The pubic shafts are slender and very slightly flexed posteroventrally, an as in all specimens of Archaeopteryx, the distal end of the ischium is bifurcated. The femora are also poorly preserved and largely collapsed. Both tibiae are preserved in articulation with the fibulae and the proximal tarsals. The digits of the feet are complete on both sides, but partially overlapping.

Until recently, the referral of new specimens from the Solnhofen Archipelago to the genus Archaeopteryx, seems unproblematic, but the re-examination of the fourth (Haarlem) specimen of Archaeopteryx, and the discovery in the last years of specimens from the Late Jurassic of China that are similar to Archaeopteryx, raises the question if the specimens referred to Archaeopteryx represent a monophyletic taxon.



Rauhut OWM, Foth C, Tischlinger H. (2018The oldest Archaeopteryx (Theropoda: Avialiae): a new specimen from the Kimmeridgian/Tithonian boundary of Schamhaupten, BavariaPeerJ 6:e4191

Foth C, Rauhut OWM. 2017. Re-evaluation of the Haarlem Archaeopteryx and the radiation of maniraptoran theropod dinosaurs. BMC Evolutionary Biology 17:236

MEYER v., H. (1861): Archaeopterix lithographica (Vogel-Feder) und Pterodactylus von Solenhofen. Neues Jahrbuch fur Mineralogie, Geognosie, Geologie und Petrefakten-Kunde. 6: 678-679

Wellnhofer Peter, A short history of research on Archaeopteryx and its relationship with dinosaurs, Geological Society, London, Special Publications, 343:237-250, doi:10.1144/SP343.14, 2010

Our once and future oceans

Earth is the only planet in our Solar System with high concentrations of gaseous diatomic oxygen. Simultaneously, this unique feature of Earth’s atmosphere has allowed the presence of an ozone layer that absorbed UV radiations. The progressive oxygenation of the atmosphere and oceans was sustained by an event of high organic carbon burial, called the Paleoproterozoic Lomagundi Event (ca. 2.3-2.1 billion years ago), which lasted well over 100 million years.

Oxygen is fundamental to life, and influences biogeochemical processes at their most fundamental level. But the oxygen content of Earth has varied greatly through time. In Earth history there have been relatively brief intervals when a very significant expansion of low-oxygen regions occurred throughout the world’s oceans. The discovery of black shales at many drill sites from the Atlantic, Indian, and the Pacific Ocean led to the recognition of widespread anoxic conditions in the global ocean spanning limited stratigraphic horizons. In 1976, S. O. Schlanger and H. C. Jenkyns termed these widespread depositional black shale intervals as “Oceanic Anoxic Events”. This was one of the greatest achievement of the DSDP (Deep Sea Drilling Project).

Corals one of the most vulnerable creatures in the ocean. Photo Credit: Katharina Fabricius/Australian Institute of Marine Science

Human activity is a major driver of the dynamics of Earth system. After the World War II, the impact of human activity on the global environment dramatically increased. Over the past 50 years, open ocean lost an estimated 2%, or 4.8 ±2.1 petamoles (77 billion metric tons), of its oxygen, and ocean oxygen minimum zones (OMZs) have expanded by an area about the size of the European Union. Deoxygenation is linked to other ocean stressors, including warming and acidification.

Ocean warming reduces the solubility of oxygen, and raises metabolic rates accelerating the rate of oxygen consumption. Warming also influence on thermal stratification and indirectly enhances salinity driven stratification through its effects on ice melt and precipitation. The increased stratification alters the mainly wind-driven circulation in the upper few hundred meters of the ocean and slows the deep overturning circulation. Intensified stratification may account for the remaining 85% of global ocean oxygen loss by reducing ventilation nd by affecting the supply of nutrients controlling production of organic matter and its subsequent sinking out of the surface ocean. Warming is predicted to exacerbate oxygen depletion in coastal systems through mechanisms similar to those of the open ocean.

Time scale [Gradstein et al., 2005] illustrating the stratigraphic position and nomenclature of OAEs (From Jenkyns, 2010).

The geological records show that large and rapid global warming events occurred repeatedly during the course of Earth history. The growing concern about modern climate change has accentuated interest in understanding the causes and consequences of these ancient abrupt warming events. The early Toarcian Oceanic Anoxic Event  (T-OAE; ∼183 mya) in the Jurassic Period is associated with a major negative carbon isotope excursion, mass extinction, marine transgression and global warming. Besides, the marked expansion of the oxygen minimum zone over the last decades, is quite similar to the model originally invoked for the genesis of Cretaceous OAEs. The better understanding of the Mesozoic ocean-climate system and the formation of OAEs would help us to predict environmental and biotic changes in a future greenhouse world.



Jenkyns, H. C. (2010), Geochemistry of oceanic anoxic eventsGeochem. Geophys. Geosyst.11, Q03004, doi:10.1029/2009GC002788.

Holz, M., Mesozoic paleogeography and paleoclimates – a discussion of the diverse greenhouse and hothouse conditions of an alien world, Journal of South American Earth Sciences (2015), doi: 10.1016/j.jsames.2015.01.001

Tennant, J. P., Mannion, P. D., Upchurch, P., Sutton, M. D. and Price, G. D. (2016), Biotic and environmental dynamics through the Late Jurassic–Early Cretaceous transition: evidence for protracted faunal and ecological turnover. Biol Rev. doi:10.1111/brv.12255 


Introducing Caihong juji

Caihong juji holotype specimen (Hu, et al., 2018)

Over the last 10 years, theropod dinosaurs from the Middle-Late Jurassic Yanliao Biota have offered rare glimpses of the early paravian evolution and particularly the origin of birds. The first discovered Yanliao non-scansoriopterygid theropod was Anchiornis huxleyi, and since then several other extremely similar species have also been reported. Caihong juji, a newly discovered Yanliao specimen, exhibits an array of osteological features, plumage characteristics, and putative melanosome morphologies not previously seen in other Paraves. The name Caihong is from the Mandarin ‘Caihong’ (rainbow). The specific name, juji is from the Mandarin ‘ju’ (big) and ‘ji’ (crest), referring to the animal’s prominent lacrimal crests.

The holotype (PMoL-B00175) is a small, articulated skeleton with fossilized soft tissues, preserved in slab and counter slab, collected by a local farmer from Qinglong County, Hebei Province, China, and acquired by the Paleontological Museum of Liaoning in February, 2014. The specimen (estimated to be ~400 mm in total skeletal body length with a body mass of ~475 g) exhibits the following autapomorphies within Paraves: accessory fenestra posteroventral to promaxillary fenestra, lacrimal with prominent dorsolaterally oriented crests, robust dentary with anterior tip dorsoventrally deeper than its midsection and short ilium.

Caihong juji differs from Anchiornis huxleyi in having a shallow skull with a long snout, forelimb proportionally short, and forearm proportionally long. Caihong also resembles basal troodontids and to a lesser degree basal dromaeosaurids in dental features (anterior teeth are slender and closely packed, but middle and posterior teeth are more stout and sparsely spaced; and serrations are absent in the premaxilla and anterior maxilla).

Platelet-like nanostructures in Caihong juji and melanosomes in iridescent extant feathers (Hu, et al., 2018)

Feathers are well preserved over the body, but in some cases, they are too densely preserved to display both gross and fine morphological features. The contour feathers are proportionally longer than those of other known non-avialan theropods. The tail feathers resemble those of Archaeopteryx, and the troodontid Jinfengopteryx in having large rectrices attaching to either side of the caudal series forming a frond-shaped tail, a feature that has been suggested to represent a synapomorphy for the Avialae.

But, the most remarkable feature observed in Caihong, is the presence of some nanostructures preserved in the head, chest, and parts of its tail, that have been identified as melanosomes. They are long, flat, and organized into sheets, with a pattern similar of those of the iridescent throat feathers of hummingbirds.

Recovered as a basal deinonychosaur, Caihong shows the earliest asymmetrical feathers and proportionally long forearms in the theropod fossil record wich indicates locomotor differences among closely related Jurassic paravians and has implications for understanding the evolution of flight-related features.


Hu, et al. A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution. Nature (2018) doi:10.1038/s41467-017-02515-y

Godefroit, P. et al. A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds. Nature 498, 359–362 (2013).

The last terror birds

Skeleton of the terror bird Titanis walleri at the Florida Museum of Natural History.

In 1887, Florentino Ameghino, the “father of Argentinian Palaeontology”, described a large, toothless jaw from the Miocene of the Province of Santa Cruz, naming it Phorusrhacos longissimus and assigning it to a new family of edentulous mammal. He used this finding as a critical evidence for his contention that modern mammalian lineages originated in Argentina and later spread across the globe. Four years later, Moreno and Mercerat recognized for the first time that the mandible described by Ameghino was really that of a bird.

The Phorusrhacidae, the so-called “terror birds”, were a group of medium-to large sized extinct ground-dwelling birds, which lived during the Cenozoic, and became the dominant carnivores of South America while it was an isolated continent. They are characterized by their elongated hindlimbs, narrow pelvis, reduced forelimbs, and their huge skull with their tall, long, narrow, and hollow beaks ended in a hook. Kelenken guillermoi, is the largest known phorusrhacid and lived in the Miocene of Argentina. The skull reaches a length of 71.6 cm and the whole animal would reach 3 m high. Kelenken is also represented by a tarsometatarsus and a broken phalanx and proceeds from the locality of Comallo (Río Negro Province, Argentina). Titanis walleri, lived during the Pliocene and Pleistocene of North America. It was 2.5 metres tall and weighed approximately 150 kilograms. This giant bird is interpreted as an early immigrant during the Great American Interchange.

Proximal portion of the left humerus of Psilopterus sp. Caudal, b ventral, c cranial and d dorsal views (From Jones et. al., 2017)

At the end of the Pliocene, Phorusrhacids decline in diversity. Two new specimens support the hypothesis that the latest geologic occurrence of the Phorusrhacidae comes from late Pleistocene sediments of Uruguay. The remains comprise the distal portion of right tarsometatarsus and a left humerus; the latter is assigned to the genus Psilopterus. The first material (MPAB-520) comes from Soriano, Uruguay, and the sediments belong to the Dolores Formation (Lujanian Stage-Age, late Pleistocene/early Holocene). The following features identify the specimen as a phorusrhacid bird. (1) a large and distally expanded trochlea metatarsi III; (2) a very narrow trochlea metatarsi II with the articular surface transversally convex and without any longitudinal sulcus (in dorsal and distal views); (3) in dorsal view the trochlea metatarsi II is almost parallel and much shorter than the middle trochlea, and forming a narrow notch between trochleae II and III. The second material consists of a left humerus without distal epiphysis belonged to Museo Paleontológico Alejandro Berro (MPAB-2024).

There are two explanatory hypotheses proposed for the decline of the terror birds: environmental reasons or direct competition (at least for the larger specimens) with placental carnivore’s immigrants to South America after the setting of the Panamanian bridge. 



Jones, W., Rinderknecht, A., Alvarenga, H. et al. PalZ (2017), The last terror birds (Aves, Phorusrhacidae): new evidence from the late Pleistocene of Uruguay,

ALVARENGA, Herculano M.F.  and  HOFLING, Elizabeth. Systematic revision of the Phorusrhacidae (Aves: Ralliformes). Pap. Avulsos Zool. (São Paulo) [online]. 2003, vol.43, n.4 [cited  2015-03-24], pp. 55-91 .

Top fossils discoveries of 2017


Skeletal anatomy of Shringasaurus indicus (From Sengupta et al., 2017)

On April 22, 2017, the March for Science reunited more than a million persons worldwide to protest against the attack on science, budget cuts and censorship. A fight that doesn’t over yet. But despite all that, 2017 was also an extraordinary year for palaeontological discoveries. My top list includes:

  • Borealopelta

Holotype of Borealopelta markmitchelli

Borealopelta markmitchelli, from the Early Cretaceous of Alberta, is a three-dimensionally preserved ankylosaurian,  discovered in the Suncor Millennium Mine in Canada. The generic name Borealopelta is derived from “borealis” (Latin, “northern”) and “pelta” (Greek, “shield”). The holotype (TMP 2011.033.0001), with an estimated living mass of 1,300 kg, is an articulated specimen preserving the head, neck, most of the trunk and sacrum, a complete right and a partial left forelimb and manus, and partial pes. The skull is covered in dermal plates, which are overlain by their associated epidermal scales. Cervical and thoracic osteoderms form continuous transverse rows completely separated by transverse rows of polygonal basement scale. Osteoderms are covered by a thick, dark gray to black organic layer, representing the original, diagenetically altered, keratinous epidermal scales. The distribution of the film correlates well to the expected distribution of melanin, a pigment present in some vertebrate integumentary structures. The keratinized tissues in this nodosaur are heavily pigmented. The possible presence of eumelanin and pheomelanin, suggested it had reddish-brown camouflage. The evidence of countershading in a large, heavily armored herbivorous dinosaur also provides a unique insight into the predator-prey dynamic of the Cretaceous Period.

  • Isaberrysaura


Isaberrysaura skull in lateral view and maxillary teeth (Adapted from Salgado et al., 2017)


Isaberrysaura mollensis gen. et sp. nov. is the first dinosaur recovered in the marine-deltaic deposits of the Los Molles Formation (Neuquén Province, Argentina), and the first neornithischian dinosaur known from the Jurassic of South America. The holotype of Isaberrysaura is an incomplete articulated skeleton with an almost complete skull, and a partial postcranium consisting of 6 cervical vertebrae, 15 dorsal vertebrae, a sacrum with a partial ilium and an apparently complete pubis, 9 caudal vertebrae, part of a scapula, ribs, and unidentifiable fragments. One of the most notable features of the discovery is the presence of permineralized seeds in the middle-posterior part of the thoracic cavity. The seeds were assigned to the Cycadales (Zamiineae) on the basis of a well-defined coronula in the micropylar region. The findings suggest the hypothesis of interactions (endozoochory) between cycads and dinosaurs, especially in the dispersion of seeds.

  •  Junornis 


Holotype of Junornis houi. From Chiappe et. al; 2017)

Junornis houi, from the Yixian Formation of eastern Inner Mongolia, represents a new addition to the enantiornithine diversity of the Jehol BiotaThe holotype (BMNHC-PH 919; Beijing Museum of Natural History), from the Early Cretaceous (~ 126±4 mya) of Yixian Formation,  is a nearly complete and articulated skeleton contained in two slabs, and surrounded by feather impressions defining the surface of its wings and body outline. Based on the well-preserved skeleton and exquisite plumage of Junornis, it was possible  make some estimation of its flight capacity. The body and wings of this bird were similar to those of modern passeriforms such as Alauda arvensis. 

  • Shringasaurus

Cranial anatomy of Shringasaurus indicus

In the aftermath of the Permo-Triassic mass extinction (~252 Ma), well diversified archosauromorph groups appear for the first time in the fossil record, including aquatic or semi aquatic forms, highly specialized herbivores, and massive predators. Allokotosaurians, meaning “strange reptiles” in Greek, comprise a bizarre suite of herbivorous archosauromorphs with a high disparity of craniodental features. Shringasaurus indicus, from the early Middle Triassic of India, is a new representative of the Allokotosauria. The generic name is derived from ‘Śṛṅga’ (Shringa), horn (ancient Sanskrit), and ‘sauros’ (σαῦρος), lizard (ancient Greek), referring to the horned skull.  The species name ‘indicus’, refers to the country where it was discovered. The holotype ISIR (Indian Statistical Institute, Reptile, India) 780, consist of a partial skull roof (prefrontal, frontal, postfrontal, and parietal) with a pair of large supraorbital horns. The fossil bones have been collected from the Denwa Formation of the Satpura Gondwana Basin. At least seven individuals of different ontogenetic stages were excavated in the same area. Most of them were disarticulated, with exception of a partially articulated skeleton.

  • Patagotitan 

Patagotitan reconstruction (Image: Diego Pol)

Patagotitan mayorum, originally discovered in 2010 by the rural farmer Aurelio Hernandez  is the largest and the most complete titanosaur taxa recovered to date. The generic name Patagotitan is derived from Patago (in reference to the geographic origin of the fossils, Patagonia), and titan (symbolic of its large size). The species name honours the Mayo family (owner of La Flecha Farm, the place where the fossils were found). The holotype (MPEF-PV 3400), includes an anterior and two middle cervical vertebrae, three anterior, two middle and two posterior dorsal vertebrae, six anterior caudal vertebrae, three chevrons, dorsal ribs, both sternal plates, right scapulocoracoid, both pubes and both femora. Six individuals were found in the same quarry, distributed in three distinct but closely spaced horizons, corresponding to  three different burial events. The first estimations of Patagotitan body mass suggest that it would weigh around 70 tons. The dorsal vertebrae preserved in Patagotitan, Argentinosaurus and Puertasaurus allows distinguishing the new taxon from previously known giant titanosaurs from the ‘mid-Cretaceous’ of Patagonia.



Brown, C.M.; Henderson, D.M.; Vinther, J.; Fletcher, I.; Sistiaga, A.; Herrera, J.; Summons, R.E. “An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics”. Current Biology. doi:10.1016/j.cub.2017.06.071

Salgado, L. et al. A new primitive Neornithischian dinosaur from the Jurassic of Patagonia with gut contents. Sci. Rep. 7, 42778; doi: 10.1038/srep42778 (2017)

Liu D, Chiappe LM, Serrano F, Habib M, Zhang Y, Meng Q (2017) Flight aerodynamics in enantiornithines: Information from a new Chinese Early Cretaceous bird. PLoS ONE12(10): e0184637.

Saradee Sengupta, Martín D. Ezcurra and Saswati Bandyopadhyay. 2017. A New Horned and Long-necked Herbivorous Stem-Archosaur from the Middle Triassic of India. Scientific Reports. 7, Article number: 8366. DOI: s41598-017-08658-8

Carballido JL, Pol D, Otero A, Cerda IA, Salgado L, Garrido AC, Ramezani J, Cúneo NR, Krause JM. 2017 A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs. Proc. R. Soc. B 284: 20171219.
DOI: 10.1098/rspb.2017.1219

Pisanosaurus and the Triassic ornithischian crisis

Pisanosaurus mertii holotype. Dorsal vertebrae in left lateral (A) and right lateral (B) views. Scale bar: 5 cm. From Agnolín and Rozadilla, 2017.

In 1887, Harry Govier Seeley was the first to subdivide dinosaurs into Saurischians and the Ornithischians based on the nature of their pelvic bones and joints. While the clade Saurischia is well represented in the Late Triassic, the record of the Ornithischia is certainly more problematic. Only a single Triassic ornithischian taxon was generally considered to still be valid: Pisanosaurus mertii, originally described by Argentinian paleontologist Rodolfo Casamiquela in 1967, based on a poorly preserved but articulated skeleton from the upper levels of the Ischigualasto Formation (Late Triassic).

The holotype and only known specimen (PVL 2577) is a fragmentary skeleton including partial upper and lower jaws, seven articulated dorsal vertebrae, four fragmentary vertebrae of uncertain position in the column; the impression of the central portion of the pelvis and sacrum; an articulated partial hind limb including the right tibia; fibula; proximal tarsals and pedal digits III and IV; the distal ends of the right and left femora; a left scapular blade (currently lost); a probable metacarpal III;  and the impressions of some metacarpals (currently lost).

Reconstructed skeleton reflecting the traditional interpretation of Pisanosaurus (Royal Ontario Museum)

But Pisanosaurus shows some derived traits that resulted as unambiguous synapomorphies of the Silesauridae clade, and include: reduced to absent denticles on maxillary and dentary teeth; sacral ribs shared between two sacral vertebrae; lateral side of proximal tibia with a fibular flange; dorsoventrally flattened ungual phalanges; and ankylothecodonty, teeth partially fused to maxilla and dentary bone. The inclusion of Pisanosaurus within Silesauridae implies that this taxon does not constitute the oldest ornithischian. This is consistent with previous interpretations proposing that ornithischian radiation occurred after the Triassic–Jurassic boundary.

To explain the relatively low diversity exhibited by Ornithischia in the Late Triassic-Early Jurassic, several hypotheses have been proposed. One, suggests that Ornithischia is the sister-taxon of Neotheropoda (the least inclusive clade that includes Coelophysis and modern birds) within the clade of ‘traditional theropod taxa’. In this model, a ‘transitional’ ornithischian may possess some anatomical features of theropods that appear to be more like those in more derived than Eodromaeus murphi and Tawa hallae.

Hypothesis 4, in which Ornithischia forms the sister-taxon of Averostra (From Baron 2017)

In a second hypothesis, Ornithischia is positioned as the sister-taxon to the coelophysids. In this model, Neotheropoda and Ornithoscelida would encompass the same set of taxa, but Ornithoscelida would, theoretically, take priority of Neotheropoda as it is the older name. In a third hypothesis, Ornithischia is positioned as the sister-taxon to the ‘other neotheropods’ not contained in the coelophysid clade.

Another hypothesis proposes that Ornithischia forms the sister-taxon of Averostra. Like Ornithischia, Averostra is only known from the Jurassic and Cretaceous Periods, and both share a number of anatomical features, such as fusion of the sacral neural. Another anatomical traits that could unite such a group include the possession of six or more sacral vertebrae; and the fusion of the sacral neural spines into a broad and continuous sheet, as in early ornithischians like Lesothosaurus diagnosticus and tetanuran theropods like Megalosaurus bucklandii. It’s worth mentioning the fact the earliest known unambiguous members of both Ornithischia and Averostra, are found in the same formation in South America: Laquintasaura venezuelae and Tachiraptor admirabilis.

Laquintasaura venezuelae gen. et sp. nov (From Barret et al., 2014)


It was suggested (Baron and Barrett 2017) that Chilesaurus diegosaurezi from the Late Jurassic, might represent the earliest diverging member of Ornithischia. Chilesaurus shows several characters typical of ornithischians. The features include a premaxilla with an edentulous anterior region;  loss of recurvature in maxillary and dentary teeth; a postacetabular process that is 25–35% of the total anteroposterior length of the ilium; possession of a retroverted pubis; a pubis with a rod-like pubic shaft; a pubic symphysis that is restricted to the distal end of the pubis; and a femur that is straightened in anterior view. The unique combination of ‘primitive’ and ‘derived’ characters for Chilesaurus has the potential to illuminate the order in which traditional ornithischian synapomorphies were acquired.

The Phytodinosauria hypothesis suggest that Ornithischia is nested among the taxa traditionally termed as sauropodomorphs could also offer a solution to the problem of the lack of unambiguous ornithischians in the Carnian and Late Triassic in general.



Baron, M. G. (2017): Pisanosaurus mertii and the Triassic ornithischian crisis: could phylogeny offer a solution?, Historical Biology, DOI: 10.1080/08912963.2017.1410705

Agnolín FL, Rozadilla S. (2017): Phylogenetic reassessment of Pisanosaurus mertii Casamiquela, 1967, a basal dinosauriform from the Late Triassic of Argentina, Journal of Systematic Palaeontology DOI: 10.1080/14772019.2017.1352623

Baron M. G, Barrett P. M. 2017, A dinosaur missing-link? Chilesaurus and the early evolution of ornithischian dinosaurs. Biol. Lett. 13: 20170220.

Baron, M. G., Norman, D. B. & Barrett, P. M. A new hypothesis of dinosaur relationships and early dinosaur evolution.  Nature 543, 501–506  (2017).  doi:10.1038/nature21700

Barrett, Paul M.; Butler, Richard J.; Mundil, Roland; Scheyer, Torsten M.; Irmis, Randall B.; Sánchez-Villagra, Marcelo R. (2014). A palaeoequatorial ornithischian and new constraints on early dinosaur diversification, Proceedings of the Royal Society B, DOI: 10.1098/rspb.2014.1147

Max C. Langer, Martín D. Ezcurra, Oliver W. M. Rauhut, Michael J. Benton, Fabien Knoll, Blair W. McPhee, Fernando E. Novas, Diego Pol & Stephen L. Brusatte, Untangling the dinosaur family tree, Nature 551 (2017) doi; oi:10.1038/nature24012

Padian K. Dividing the dinosaurs. Nature 543, 494–495 (2017) doi:10.1038/543494a


The bizarre Halszkaraptor escuilliei

H. escuilliei MPC D-102/109. From Cau et al., 2017.

Maniraptoran lineages evolved novel ecomorphologies during the Cretaceous period, including active flight, gigantism, cursoriality and herbivory. This group share the following characteristics: large brain but a reduced skull in comparison to their body size, beaks, and smaller teeth. Now, a well-preserved maniraptoran from Mongolia, revealed a mosaic of features, most of them absent among non-avian maniraptorans but shared by reptilian and avian groups with aquatic or semiaquatic ecologies. This new theropod, Halszkaraptor escuilliei gen. et sp. nov., adds an amphibious ecomorphology to those evolved by maniraptorans.

The holotype, MPC (Institute of Paleontology and Geology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia) D-102/109, is an articulated and almost complete skeleton preserved three-dimensionally. The generic name, honours Halszka Osmólska (1930–2008) for her contributions to theropod palaeontology. The species name, ‘escuilliei’ refers to François Escuillié, who returned the holotype to Mongolia.

Reconstruction of Halszkaraptor escuilliei. Photograph: Lukas Panzarin/Andrea Cau

Halszkaraptor is related to other enigmatic Late Cretaceous maniraptorans from Mongolia in a novel clade at the root of Dromaeosauridae. It was the size of a mallard. Originally poached from Ukhaa Tolgod, Mongolia, the fossil was in private collections in Japan and England for an unknown amount of time, and later it  was transferred to the Royal Belgian Institute of Natural Sciences (RBINS). Thanks to a cooperation agreement between the Ministry of Education, Culture and Science of Mongolia, the Belgian Science Policy Office and the RBINS, the specimen returned to the Institute of Paleontology and Geology, Mongolian Academy of Science.

The skeleton is almost complete. The skull is lightly built, and is still articulated with the first cervical vertebra. The preorbital region forms 60% of basicranial length, and each premaxilla is elongate, bearing eleven teeth, the highest number among dinosaurs. The presacral vertebrae include 10 cervicals and 12 dorsals. The neck forms 50% of snout–sacrum length.

Skull of H. escuilliei. From Cau et al., 2017

The forelimb is relatively shorter than in most dromaeosaurids. The ulna is flattened and possesses an acute posterior margin. The hand has a morphology that is unique among theropods, with a progressive elongation of the lateral fingers, with the third being the longest and most robust. The 76 mm long femur has a robust greater trochanter. The metatarsus lacks cursorial adaptations and measures 80% of femoral length. The feet are complete and articulated, although some elements are poorly visible.

Based on the neck hyperelongation for food procurement, the forelimb proportions that may support a swimming function, and postural adaptations convergent with short-tailed birds, Halszkaraptor may represent the first case among non-avian dinosaurs of a double locomotory module.


Cau, A.; Beyrand, V.; Voeten, D.; Fernandez, V.; Tafforeau, P.; Stein, K.; Barsbold, R.; Tsogtbaatar, K.; Currie, P.; Godrfroit, P.; “Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs”. Nature. doi:10.1038/nature2467