Some lovely examples of Douvilleiceras mammillatum (Schlotheim, 1813), ammonites from the Lower Cretaceous (Middle-Lower Albian) Douvilliceras inequinodum zone of Ambarimaninga, Mahajanga Province, Madagascar.
The genus Douvilleiceras range from Middle to Late Cretaceous and can be found in Asia, Africa, Europe and North and South America. We have beautiful examples in the early to mid-Albian from the archipelago of Haida Gwaii in British Columbia. Joseph F. Whiteaves was the first to recognize the genus from Haida Gwaii when he was looking over the early collections of James Richardson and George Dawson. The beauties you see here measure 6cm to 10cm.

Monday, 9 December 2019
Sunday, 8 December 2019
Saturday, 7 December 2019
JURASSIC STARFISH
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At a glance, sea stars and brittle stars look quite similar. These echinoderms generally have five radiating arms (or a multiple thereof) and creep along on the seafloor using their arms for locomotion. And they come in wonderful colours.
Sea stars and brittle stars look similar and are related but are actually quite different.
Both sea stars and brittle stars are in the phylum Echinodermata, which also includes sea cucumbers, sea urchins, sand dollars and sea lilies. The most common brittle star is the long-armed brittle star, Amphipholis squamata, a gray-blue, luminescent (glowing) species.
Echinoderms can be found making a living in our oceans and are known for their five-point radial symmetry and unique water vascular system. They typically have a tough, spiny surface, which inspired their name. In Greek, echinos means “spiny” and derma means “skin.”
A neat little evolutionary feature of these lovelies is their ability to regrow lost body parts, and sea stars and brittle stars can regrow arms if broken off or eaten.
Within the phylum, sea stars and brittle stars are in different classes. Sea stars are in the class Asteroidea, where brittle stars are in Ophiuroidea, which also includes basket stars.
To tell the two apart, first, look at their bodies. The modern brittle star you see to the right looks delicate, almost spindly. The sea stars you see below are more robust. Their fundamental structure is different, especially when you look at where the arms connect to the center of the body. Brittle stars have tube feet along their arms that sense light and scent.
Sea stars have thicker, triangular-shaped arms that are typically their widest at the point of connection to the center of the body. They can be found in blue, red, orange, purple, pink, white and a mixture of those same colours.
Brittle stars, on the other hand, have much thinner, more delicate arms that appear more snake-like. Their arms connect to a central disk but do not touch one another.
Sea stars rely on their water vascular system to move. The water vascular system includes a number of small tube feet that become stiff when water is pushed into them, allowing the sea star to move on a conveyor belt-like rotation of feet.
Although brittle stars also have a water vascular system, they twist and bend their long arms to move, instead. This means that they can move much more quickly than sea stars, especially when trying to escape a predator. Handy that!
Friday, 6 December 2019
PSEUDOTHURMANNIA PICTETI
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Pseudothurmannia picteti, Photo: Manuel Peña Nieto |
These fast-moving nektonic carnivores lived in the Cretaceous period, from the Hauterivian to the Barremian.
Shells of Pseudothurmannia can reach a diameter of about 4–12 centimetres (1.6–4.7 in). They show flat or slightly convex sides, a surface with dense ribs and a subquadrate whorl section.
We find fossils of Pseudothurmannia in Cretaceous outcrops in Antarctica, Czechoslovakia, France, Hungary, Italy, Japan, Morocco, Spain, Russia and the United States. The specimen you see here is in the collection of Manuel Peña Nieto from Córdoba, Spain and is from the Lower Cretaceous of Mallorca.
Wednesday, 4 December 2019
Tuesday, 3 December 2019
GAVIALOSUCHUS CROCODILE OF CHELAS
This well-preserved Miocene fossil crocodile is Gavialosuchus americanus lusitanicus, (Sellards, 1915) who lived in the area near Chelas, a locality near the airport in Lisbon, Portugal around 12 million years ago. When he was alive, that area of the world was flooded and home to Mastodons and other ancient animals.
This fellow was quite the beast. The complete crocodile would have been 8-9 meters in length. Crocodiles are reptiles, which means that they are cold-blooded, are covered in dry, scaly skin, and have a backbone. They are sometimes called ‘living fossils’ because they have been living on Earth since the time of the dinosaurs.
Although they have been around for millions of years, their bodies have not changed very much during that time because they are such successful predators. Unlike alligators, crocodiles have very pointed snouts, and their upper and lower jaws are the same size. Crocodiles have webbed feet, which makes them fast swimmers.
Their bodies are very streamlined, meaning they can slide quickly through the water to catch their prey. Their size depends on the crocodile species with some modern species growing to over 7 meters (23 feet) long and weighing about 1,000 kilograms or 2,200 pounds. This ancient specimen is now housed in the Geological Museum of Lisbon. He would have been bigger than his modern cousins and a formidable predator. Luis Lima recently had the pleasure of visiting their collections and shared this photo. The museum was built in 1857 and is home to beautiful paleontology, archaeology and mineral specimens. Should you find yourself in Lisbon, it is well worth a trip.
This fellow was quite the beast. The complete crocodile would have been 8-9 meters in length. Crocodiles are reptiles, which means that they are cold-blooded, are covered in dry, scaly skin, and have a backbone. They are sometimes called ‘living fossils’ because they have been living on Earth since the time of the dinosaurs.
Their bodies are very streamlined, meaning they can slide quickly through the water to catch their prey. Their size depends on the crocodile species with some modern species growing to over 7 meters (23 feet) long and weighing about 1,000 kilograms or 2,200 pounds. This ancient specimen is now housed in the Geological Museum of Lisbon. He would have been bigger than his modern cousins and a formidable predator. Luis Lima recently had the pleasure of visiting their collections and shared this photo. The museum was built in 1857 and is home to beautiful paleontology, archaeology and mineral specimens. Should you find yourself in Lisbon, it is well worth a trip.
Monday, 2 December 2019
Sunday, 1 December 2019
AMMONITE OF THE RHÔNE
An exquisite specimen of the delicately ridged ammonite, Porpoceras verticosum, from Middle Toarcian outcrops adjacent the Rhône in southeastern France.
Porpoceras (Buchman, 1911) is a genus of ammonite that lived during the early and middle Toarcian stage of the Early Jurassic. We see members of this genus from the uppermost part of Serpentinum Zone to Variabilis Subzone. These beauties are found in Europe, Asia, North America and South America.
Ammonites belonging to this genus have evolute shells, with compressed to depressed whorl section. Flanks were slightly convex and venter has been low. The whorl section is sub-rectangular. The rib is pronounced and somewhat fibulate on inner whorls (just wee nodes here) and tuberculate to spined on the ventrolateral shoulder. It differs from Peronoceras by not having a compressed whorl section and regular nodes or fibulation. Catacoeloceras is also similar, but it has regular ventrolateral tubercules and is missing the classic nodes or fibulation of his cousins.
This specimen hails from southern France near the Rhône, one of the major rivers of Europe. It has twice the average water level of the Loire and is fed by the Rhône Glacier in the Swiss Alps at the far eastern end of the Swiss canton of Valais then passes through Lake Geneva before running through southeastern France. This 10 cm specimen was prepared by the supremely talented José Juárez Ruiz
Porpoceras (Buchman, 1911) is a genus of ammonite that lived during the early and middle Toarcian stage of the Early Jurassic. We see members of this genus from the uppermost part of Serpentinum Zone to Variabilis Subzone. These beauties are found in Europe, Asia, North America and South America.
Ammonites belonging to this genus have evolute shells, with compressed to depressed whorl section. Flanks were slightly convex and venter has been low. The whorl section is sub-rectangular. The rib is pronounced and somewhat fibulate on inner whorls (just wee nodes here) and tuberculate to spined on the ventrolateral shoulder. It differs from Peronoceras by not having a compressed whorl section and regular nodes or fibulation. Catacoeloceras is also similar, but it has regular ventrolateral tubercules and is missing the classic nodes or fibulation of his cousins.
This specimen hails from southern France near the Rhône, one of the major rivers of Europe. It has twice the average water level of the Loire and is fed by the Rhône Glacier in the Swiss Alps at the far eastern end of the Swiss canton of Valais then passes through Lake Geneva before running through southeastern France. This 10 cm specimen was prepared by the supremely talented José Juárez Ruiz
Saturday, 30 November 2019
Friday, 29 November 2019
T. REX: THE ULTIMATE PREDATOR
The first skeleton of Tyrannosaurus rex was discovered in 1902 in Hell Creek, Montana, by the Museum's famous fossil hunter Barnum Brown. Six years later, Brown discovered a nearly complete T. rex skeleton at Big Dry Creek, Montana.
The rock around it was blasted away with dynamite to reveal a “magnificent specimen” with a “perfect” skull. This skeleton, AMNH 5027, is on view in the American Museum of Natural History's Hall of Saurischian Dinosaurs. It's also reproduced in their new exhibition T. rex: The Ultimate Predator Exhibition should you find yourself lucky enough to be in New York.
The rock around it was blasted away with dynamite to reveal a “magnificent specimen” with a “perfect” skull. This skeleton, AMNH 5027, is on view in the American Museum of Natural History's Hall of Saurischian Dinosaurs. It's also reproduced in their new exhibition T. rex: The Ultimate Predator Exhibition should you find yourself lucky enough to be in New York.
Thursday, 28 November 2019
NATURAL HISTORY MUSEUM LONDON
The Natural History Museum in London is a natural history museum that exhibits a vast range of specimens from various segments of natural history. It is one of three major museums on Exhibition Road in South Kensington, the others being the Science Museum and the Victoria and Albert Museum.
The museum is home to life and earth science specimens comprising some 80 million items within five main collections: botany, entomology, mineralogy, paleontology and zoology. The museum is also a centre of research specializing in taxonomy, identification and conservation. Given the age of the institution, many of the collections have great historical as well as scientific value, such as specimens collected by Charles Darwin and other darlings of paleontology.
The museum is particularly famous for its exhibition of dinosaur skeletons and ornate architecture, sometimes dubbed a cathedral of nature, both exemplified by the large Diplodocus cast that dominated the vaulted central hall before it was replaced in 2017 with the skeleton of a blue whale hanging from the ceiling. Here's a photo of the unveiling ceremony at the Reptiles Callery from 1905.
The Natural History Museum Library contains extensive books, journals, manuscripts, and artwork collections linked to the work and research of the scientific departments; access to the library is by appointment only. The museum is recognized as the pre-eminent centre of natural history and research of related fields in the world.
Although commonly referred to as the Natural History Museum, it was officially known as British Museum (Natural History) until 1992, despite legal separation from the British Museum itself in 1963. Originating from collections within the British Museum, the landmark Alfred Waterhouse building was built and opened by 1881 and later incorporated the Geological Museum. The Darwin Centre is a more recent addition, partly designed as a modern facility for storing valuable collections.
Like other publicly funded national museums in the United Kingdom, the Natural History Museum does not charge an admission fee. It did back in the day but was scrapped in 2001. The museum is an exempt charity and a non-departmental public body sponsored by the Department for Culture, Media and Sport. Catherine, Duchess of Cambridge, is a patron of the museum. Today, there are approximately 850 staff at the museum. It remains my favourite of all the museums I've visited as it presents our scientific history on a grande scale.
The museum is home to life and earth science specimens comprising some 80 million items within five main collections: botany, entomology, mineralogy, paleontology and zoology. The museum is also a centre of research specializing in taxonomy, identification and conservation. Given the age of the institution, many of the collections have great historical as well as scientific value, such as specimens collected by Charles Darwin and other darlings of paleontology.
The museum is particularly famous for its exhibition of dinosaur skeletons and ornate architecture, sometimes dubbed a cathedral of nature, both exemplified by the large Diplodocus cast that dominated the vaulted central hall before it was replaced in 2017 with the skeleton of a blue whale hanging from the ceiling. Here's a photo of the unveiling ceremony at the Reptiles Callery from 1905.
The Natural History Museum Library contains extensive books, journals, manuscripts, and artwork collections linked to the work and research of the scientific departments; access to the library is by appointment only. The museum is recognized as the pre-eminent centre of natural history and research of related fields in the world.
Although commonly referred to as the Natural History Museum, it was officially known as British Museum (Natural History) until 1992, despite legal separation from the British Museum itself in 1963. Originating from collections within the British Museum, the landmark Alfred Waterhouse building was built and opened by 1881 and later incorporated the Geological Museum. The Darwin Centre is a more recent addition, partly designed as a modern facility for storing valuable collections.
Like other publicly funded national museums in the United Kingdom, the Natural History Museum does not charge an admission fee. It did back in the day but was scrapped in 2001. The museum is an exempt charity and a non-departmental public body sponsored by the Department for Culture, Media and Sport. Catherine, Duchess of Cambridge, is a patron of the museum. Today, there are approximately 850 staff at the museum. It remains my favourite of all the museums I've visited as it presents our scientific history on a grande scale.
Wednesday, 27 November 2019
PROSAUROLOPHUS MAXIMUS
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Prosaurolophus maximus, Ottawa Museum of Nature |
This crest grew isometrically (without changing in proportion) throughout the lifetime of the individual, leading to speculation that the species may have had a soft tissue display structure, such inflatable nasal sacs.
When originally described by Brown, Prosaurolophus maximus was known from a skull and jaw. Half of the skull was badly weathered at the time of examination, and the level of the parietal was distortedly crushed upwards to the side.
The different bones of the skull are easily defined with the exception of the parietals and nasal bones. Brown found that the skull of the already described genus Saurolophus is very similar overall but also smaller than the skull of P. maximus. The unique feature of a shortened frontal in lambeosaurines is also found in Prosaurolophus, and the other horned hadrosaurines Brachylophosaurus, Maiasaura, and Saurolophus. Although they lack a shorter frontal, the genera Edmontosaurus and Shantungosaurus share an elongated dentary structure.
Patches of preserved skin are known from two juvenile specimens, TMP 1998.50.1 and TMP 2016.37.1; these pertain to the ventral extremity of the ninth through fourteenth dorsal ribs, the caudal margin of the scapular blade, and the pelvic region. Small basement scales (scales which make up the majority of the skin surface), 3–7 millimetres (0.12–0.28 in) in diameter, are preserved on these patches - this is similar to the condition seen in other saurolophine hadrosaurs.
More uniquely, feature scales (larger, less numerous scales which are interspersed within the basement scales) around 5 millimetres (0.20 in) wide and 29 millimetres (1.1 in) long are found interspersed in the smaller scales in the patches from the ribs and scapula (they are absent from the pelvic patches). Similar scales are known from the tail of the related Saurolophus angustirostris (on which they have been speculated to indicate pattern), and it is considered likely adult Prosaurolophus would've retained the feature scales on their flanks like the juveniles.
Tuesday, 26 November 2019
DELGADOCRINUS OPORTOVINUM
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Delgadocrinus oportovinum |
His find resulted in the creation of a new family, Delgadocrinoinidae, a new genus and a new species.
Ausich et al. published on New and Revised Occurrences of Ordovician Crinoids from Southwestern Europe in the Journal of Paleontology, November 2007. In their work, they honour Delgado. His find was the first record of an Ordovician crinoid from Portugal, Delgadocrinus oportovinum, marking it as the oldest known crinoid from the Iberian Peninsula (Arenigian/Oretanian boundary, early Darriwilian).
The team took a comprehensive look at the Ordovician crinoids of southwestern Europe, including taxa based on articulated crowns and stems. This summary incorporates new material, new localities, and a revision of some southwestern Europe occurrences and is well worth a read. The Type Specimen you see here is now housed in the Natural History Museum of Lisbon. Luis Lima shared a photo of his recent visit to their beautiful collections and kindly granted permission to share the photo here.
Reference: Ausich, William & Sá, Artur & Gutiérrez-Marco, Juan. (2007). New and revised occurrences of Ordovician crinoids from southwestern Europe. Journal of Paleontology - J PALEONTOL. 81. 1374-1383. 10.1666/05-038.1.
Monday, 25 November 2019
ZENASPIS PODOLICA HEAD SHIELD
A Devonian bony fish mortality plate showing a lower shield of Zenaspis podolica (Lankester, 1869) from Lower Devonian deposits of Podolia, Ukraine.
Podolia or Podilia is a historic region in Eastern Europe, located in the west-central and south-western parts of Ukraine, in northeastern Moldova. Podolia is the only region in Ukraine where 420 million-year-old remains of ichthyofauna can be found near the surface, making them accessible to collection and study. Zenaspis is an extinct genus of jawless fish which thrived during the early Devonian. Being jawless, Zenaspis was probably a bottom feeder, snicking on debris from the seafloor similar to how flounder, groupers, bass and other bottom-feeding fish make a living.
For the past 150 years, vertebrate fossils have been found in more than 90 localities situated in outcrops along banks of the Dniester River and its northern tributaries, and in sandstone quarries. At present, the faunal list of Early Devonian agnathans and fishes from Podolia number seventy-two species, including 8 Thelodonti, 39 Heterostraci, 19 Osteostraci, 4 Placodermi, 1 Acanthodii, and 1 Holocephali (Voichyshyn 2001a).
In Podolia, Lower Devonian redbeds strata (the Old Red Formation or Dniester Series) are up to 1800 m thick and range from Lochkovian to Eifelian in age (Narbutas 1984; Drygant 2000, 2003).
In their lower part (Ustechko and Khmeleva members of the Dniester Series) they consist of lovely multicoloured, mainly red, fine-grained cross-bedded massive quartz sandstones and siltstones with seams of argillites (Drygant 2000).
We see fossils of Zenaspis in the early Devonian of Western Europe. Both Zenaspis pagei and Zenaspis poweri can be found up to 25 centimetres long in Devonian outcrops of Scotland.
Reference: Voichyshyn, V. 2006. New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine. Acta Palaeontologica Polonica 51 (1): 131–142. Photo care of the awesome Fossilero Fisherman.
Podolia or Podilia is a historic region in Eastern Europe, located in the west-central and south-western parts of Ukraine, in northeastern Moldova. Podolia is the only region in Ukraine where 420 million-year-old remains of ichthyofauna can be found near the surface, making them accessible to collection and study. Zenaspis is an extinct genus of jawless fish which thrived during the early Devonian. Being jawless, Zenaspis was probably a bottom feeder, snicking on debris from the seafloor similar to how flounder, groupers, bass and other bottom-feeding fish make a living.
For the past 150 years, vertebrate fossils have been found in more than 90 localities situated in outcrops along banks of the Dniester River and its northern tributaries, and in sandstone quarries. At present, the faunal list of Early Devonian agnathans and fishes from Podolia number seventy-two species, including 8 Thelodonti, 39 Heterostraci, 19 Osteostraci, 4 Placodermi, 1 Acanthodii, and 1 Holocephali (Voichyshyn 2001a).
In Podolia, Lower Devonian redbeds strata (the Old Red Formation or Dniester Series) are up to 1800 m thick and range from Lochkovian to Eifelian in age (Narbutas 1984; Drygant 2000, 2003).
In their lower part (Ustechko and Khmeleva members of the Dniester Series) they consist of lovely multicoloured, mainly red, fine-grained cross-bedded massive quartz sandstones and siltstones with seams of argillites (Drygant 2000).
We see fossils of Zenaspis in the early Devonian of Western Europe. Both Zenaspis pagei and Zenaspis poweri can be found up to 25 centimetres long in Devonian outcrops of Scotland.
Reference: Voichyshyn, V. 2006. New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine. Acta Palaeontologica Polonica 51 (1): 131–142. Photo care of the awesome Fossilero Fisherman.
Sunday, 24 November 2019
RAPA NUI SENTINELS
Rapa Nui (Easter Island) is famous for its rows of moai, towering figures of deified ancestors that were carved from volcanic tuff rock in quarries then moved to a platform on the water's edge. This plaster cast was made from a mould secured during a 1934-1935 Museum expedition to Rapa Nui, 2,000 miles west of the Chilean coast.
There are 887 moai on Rapa Nui, where they are revered, considered by islanders to be sacred. There is an excellent moai cast on exhibit at the American Natural History Museum in New York.
There are 887 moai on Rapa Nui, where they are revered, considered by islanders to be sacred. There is an excellent moai cast on exhibit at the American Natural History Museum in New York.
Saturday, 23 November 2019
CARCHARODON MEGALODON CHUBUTENSIS
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Carcharodon chubutensis. Photo: Luis Lima |
These big beasties lived during Oligocene to Miocene. This fellow is considered to be a close relative of the famous prehistoric mega-toothed shark, C. megalodon, although the classification of this species is still disputed.
Swiss naturalist Louis Agassiz first identified this shark as a species of Carcharodon in 1843. In 1906, Ameghino renamed this shark as C. chubutensis. In 1964, shark researcher, L. S. Glikman recognized the transition of Otodus obliquus to C. auriculatus. In 1987, shark researcher, H. Cappetta reorganized the C. auriculatus - C. megalodon lineage and placed all related mega-toothed sharks along with this species in the genus Carcharocles.
At long last, the complete Otodus obliquus to C. megalodon progression began to look clear. Since then, C. chubutensis has been re-named into Otodus chubutensis, also the other chronospecies of the Otodus obliquus - O. megalodon lineage. Chubutensis appears at the frontier Upper Oligocene to Lowest Miocene (evolving from O. angustidens which has stronger side cusps) and turns into O. megalodon in the Lower to Middle Miocene, where the side cusps are already absent. Despite previous publications, there is no chubutensis in the Pliocene.
Victor Perez and his team published on the transition between Carcharocles chubutensis and Carcharocles megalodon (Otodontidae, Chondrichthyes): lateral cusplet loss through time in March of 2018. In their work, they look at the separation between all the teeth of Carcharocles chubutensis and Carcharocles megalodon and published that it is next to impossible to divide them up as a complex mosaic evolutionary continuum characterizes this transformation, particularly in the loss of lateral cusplets.
The cuspleted and uncuspleted teeth of Carcharocles spp. are designated as chronomorphs because there is wide overlap between them both morphologically and chronologically. In the lower Miocene Beds (Shattuck Zones) 2–9 of the Calvert Formation (representing approximately 3.2 million years, 20.2–17 Ma, Burdigalian) both cuspleted and uncuspleted teeth are present, but cuspleted teeth predominate, constituting approximately 87% of the Carcharocles spp. teeth represented in their samples.
In the middle Miocene Beds 10–16A of the Calvert Formation (representing approximately 2.4 million years, 16.4–14 Ma, Langhian), there is a steady increase in the proportion of uncuspleted Carcharocles teeth.
In the upper Miocene Beds 21–24 of the St. Marys Formation (approx. 2.8 million years, 10.4–7.6 Ma, Tortonian), lateral cusplets are nearly absent in Carcharocles teeth from our study area, with only a single specimen bearing lateral cusplets. The dental transition between Carcharocles chubutensis and Carcharocles megalodon occurs within the Miocene Chesapeake Group. Although their study helps to elucidate the timing of lateral cusplet loss in Carcharocles locally, the rationale for this prolonged evolutionary transition remains unclear.
The specimen you see here is in the Geological Museum in Lisbon. The photo credit goes to the deeply awesome Luis Lima who shared some wonderful photos of his recent visit to their collections.
If you'd like to read the paper from Perez, you can find it here:
https://www.tandfonline.com/doi/full/10.1080/02724634.2018.1546732
Friday, 22 November 2019
HOPLOSCAPHITES NEBRASCENSIS
This sweet beauty with lovely colouring is a Hoploscaphites nebrascensis (Owen, 1852) macroconch. This is the female form of the ammonite that has a larger shell than the male, or microconch.
Hoploscaphites nebrascensis is an upper Maastrichtian species and index fossil. It marks the top of ammonite zonation for the Western Interior. This species has been recorded from Fox Hills Formation in North and South Dakota as well as the Pierre Shale in southeastern South Dakota and northeastern Nebraska.
It is unknown from Montana, Wyoming, and Colorado due to the deposition of coeval terrestrial units. It has possibly been recorded in glacial deposits in Saskatchewan and northern North Dakota, but that is hearsay. Outside the Western Interior, this species has been found in Maryland and possibly Texas in the Discoscaphites Conrad zone. This lovely one is in the collection of the deeply awesome (and enviable) José Juárez Ruiz. A big thank you to Joshua DrSlattmaster J Slattery for his insights on this species.
Hoploscaphites nebrascensis is an upper Maastrichtian species and index fossil. It marks the top of ammonite zonation for the Western Interior. This species has been recorded from Fox Hills Formation in North and South Dakota as well as the Pierre Shale in southeastern South Dakota and northeastern Nebraska.
It is unknown from Montana, Wyoming, and Colorado due to the deposition of coeval terrestrial units. It has possibly been recorded in glacial deposits in Saskatchewan and northern North Dakota, but that is hearsay. Outside the Western Interior, this species has been found in Maryland and possibly Texas in the Discoscaphites Conrad zone. This lovely one is in the collection of the deeply awesome (and enviable) José Juárez Ruiz. A big thank you to Joshua DrSlattmaster J Slattery for his insights on this species.
Thursday, 21 November 2019
Wednesday, 20 November 2019
EARLY PREDATORY DINOSAURS
Predatory dinosaurs were an important ecological component of terrestrial Mesozoic ecosystems.
Though theropod dinosaurs carried this role during the Jurassic and Cretaceous Periods (and probably the post-Carnian portion of the Triassic), it is difficult to depict the Carnian scenario, due to the scarcity of fossils.
Until now, knowledge on the earliest predatory dinosaurs mostly relies on herrerasaurids recorded in the Carnian strata of South America. Phylogenetic investigations recovered the clade in different positions within Dinosauria, whereas fewer studies challenged its monophyly.
Although herrerasaurid fossils are much better recorded in present-day Argentina than in Brazil, Argentinean strata so far yielded no fairly complete skeleton representing a single individual.
Here, the authors describe Gnathovorax cabreirai, a new herrerasaurid based on an exquisite specimen found as part of a multi-taxic association form southern Brazil. The type specimen comprises a complete and well-preserved articulated skeleton, preserved in close association (side by side) with rhynchosaur and cynodont remains.
Given its superb state of preservation and completeness, the new specimen sheds light on poorly understood aspects of the herrerasaurid anatomy, including endocranial soft tissues.
The specimen also reinforces the monophyletic status of the group and provides clues on the ecomorphology of the early carnivorous dinosaurs. Indeed, an ecomorphological analysis employing dental traits indicates that herrerasaurids occupy a particular area in the morphospace of faunivorous dinosaurs, which partially overlaps the area occupied by post-Carnian theropods. This indicates that herrerasaurid dinosaurs preceded the ecological role that later would be occupied by large to medium-sized theropods. Link to the paper: https://peerj.com/articles/7963/
Though theropod dinosaurs carried this role during the Jurassic and Cretaceous Periods (and probably the post-Carnian portion of the Triassic), it is difficult to depict the Carnian scenario, due to the scarcity of fossils.
Until now, knowledge on the earliest predatory dinosaurs mostly relies on herrerasaurids recorded in the Carnian strata of South America. Phylogenetic investigations recovered the clade in different positions within Dinosauria, whereas fewer studies challenged its monophyly.
Although herrerasaurid fossils are much better recorded in present-day Argentina than in Brazil, Argentinean strata so far yielded no fairly complete skeleton representing a single individual.
Here, the authors describe Gnathovorax cabreirai, a new herrerasaurid based on an exquisite specimen found as part of a multi-taxic association form southern Brazil. The type specimen comprises a complete and well-preserved articulated skeleton, preserved in close association (side by side) with rhynchosaur and cynodont remains.
Given its superb state of preservation and completeness, the new specimen sheds light on poorly understood aspects of the herrerasaurid anatomy, including endocranial soft tissues.
The specimen also reinforces the monophyletic status of the group and provides clues on the ecomorphology of the early carnivorous dinosaurs. Indeed, an ecomorphological analysis employing dental traits indicates that herrerasaurids occupy a particular area in the morphospace of faunivorous dinosaurs, which partially overlaps the area occupied by post-Carnian theropods. This indicates that herrerasaurid dinosaurs preceded the ecological role that later would be occupied by large to medium-sized theropods. Link to the paper: https://peerj.com/articles/7963/
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