Category: Palaeontological articles

Pliosaur Skull Links Dorking to Kansas

Pliosaur Skull Links Dorking to Kansas

For much of the later stages of the Cretaceous, the area that is now known as the British Isles lay underwater.   Bad news if you are searching for evidence of terrestrial dinosaurs, however, the limestones and chalk deposits associated with southern England can still yield some exciting surprises for vertebrate palaeontologists.  Take for example, the research of Dr. Roger Benson (University of Oxford, Dept. of Earth Sciences), who has been examining the fragmentary remains of pliosaurs associated with the lithostratigraphic unit of strata known as the Chalk Group.  Dr. Benson’s analysis of a pliosaur specimen housed in the collection of the Dorking Museum and Heritage Centre reveals that the fossils may have been misidentified, by none other than Sir Richard Owen, the anatomist who is credited with the naming of the Order Dinosauria.

An Illustration from the Original 1858 Monograph by Richard Owen

One of the original lithographs from Owen's 1858 paper.

One of the original lithographs from Owen’s 1858 paper.

Picture Credit: The Pterosaur Database/Dr. R Benson (Supplement (No. III) to the Monograph on the Fossil Reptilia of the Cretaceous Formations: 1858)

The illustration above shows some of the skull fossils and teeth described by Richard Owen as the pliosaur Polyptychodon interruptus.  The smaller illustrations to be found in the lower portion of the picture depict various pterosaur fossils.

What are Pliosaurs?

Pliosaurs, or those animals that make up the Pliosauridae clade, are an extinct group of marine reptiles, that along with the long-necked Plesiosaurs make up the Order Plesiosauria.  Pliosaurs tend have short necks and large, broad skulls.  They have a worldwide fossil distribution and they first appeared during the Early Jurassic with many of these reptiles evolving into giants that specialised in hunting other marine vertebrates like today’s killer whales.  Famous prehistoric animals such as Liopleurodon and the Australian Kronosaurus are examples of pliosaurs.

An Illustration of a Typical Pliosaur (Pliosaurus brachydeirus)

A scale drawing of a Pliosaurus.

A scale drawing of a pliosaurus.

Picture Credit: Everything Dinosaur

Having dominated marine environments for the best part of a 100 million years, with many forms becoming apex predators, towards the early Late Cretaceous remains of these reptiles disappear from the fossil record.  Around ninety million years or so ago, these sea monsters died out.  Why the Pliosaurs became extinct remains a mystery.  It is important for palaeontologists to gain as much information as they can from existing fossil specimens.  Perhaps, thanks to the careful research of Dr. Benson and the presence of many fine fossil collections held in regional museums, one day scientists may have a more complete understanding of how these great reptiles evolved and radiated out into so many forms dominating a number of marine palaeoenvironments.  Scientists might even be able to provide information on why these leviathans went into decline and died out.

The Dorking Pliosaur Specimen

During the early part of the 19th Century a number of fossils of marine reptiles were collected by amateur geologists and naturalists.  One such collection, which had been the amassed by the first Baron Ashcombe was donated to the Dorking Museum in 1948 by the first Baron’s grandson.  Amongst the specimens donated was the relatively complete skull of a pliosaur which had been discovered sometime in the 1850’s.  The first Baron Ashcombe had used his influence to invite none other than Richard Owen to examine the fossil collection.  Richard Owen, who was later to help found the Natural History Museum (London), described this skull as an example of the pliosaur Polyptychodon interruptus (Po-lip-tie-ko-don in-terr-rupt-us), the name means ” broken apart fin shaped tooth”.

When Dr. Benson visited the Dorking Museum and Heritage Centre to inspect the skull material, he noted a number of similarities between this fossil specimen and the fossils of another pliosaur, known from North America.  In addition, Dr. Benson’s study revealed that most other fossils of Polyptychodon species come from rocks that are much older than the ones found in the chalk pits in this part of Surrey (southern England).  This casts doubt over the original conclusions drawn by the celebrated anatomist Richard Owen.  It seems that the Dorking specimen may represent a type of pliosaur whose fossils are associated with Kansas.

A Fragment of the Lower Jaw

Individual tooth sockets (alveoli) can be made out along the jawbone.

Individual tooth sockets (alveoli) can be made out along the jawbone.

Picture Credit: Dr. Roger Benson (Oxford University)

Affinities with Brachauchenius

Although Owen thought the Dorking specimen belonged to Polyptychodon the shape of the skull (morphology) suggests to Dr. Benson that this specimen may actual be another type of pliosaur altogether.  Dr. Benson concludes that the Dorking specimen shares many similarities with a pliosaur known as Brachauchenius (Brak-ow-ken-ee-us) whose fossils are mainly associated with the Western Interior Seaway of the early Late Cretaceous that covered most of the land that is now known as the United States.  According to Dr. Benson’s research, most other specimens assigned to the Polyptychodon genus are around 115 million years old (Aptian age of the Cretaceous), but the Dorking fossil material comes from much younger strata, rocks that date from around 90-95 million years ago (Cenomanian to Turonian age).  This indicates that the pliosaur fossils within the collection of the Dorking Museum and Heritage Centre represents one of the last of the pliosaurs.

Part of the Lower Jaw Bone

Lateral view of part of the Pliosaur lower jaw.

A view of part of the pliosaur lower jaw.

Picture Credit: Dr. Roger Benson (Oxford University)

Our knowledge of the Pliosauridae has improved enormously since the time of Richard Owen, as has our knowledge of stratigraphy.  These collections, many of which are housed in small regional museums can still have a very significant role in research, for example, in this instance, helping to build up a better picture of an ancient marine fauna.

The Museum’s Chairman, Nigel Arch, commenting on Dr. Benson’s visit stated that it was:

“a good example of the value of our collections and the fact that we can always learn more.  It is wonderful to think that the study of this specimen, found locally and collected by a local person, is still contributing to scientific knowledge today.” 

A Pliosaur Tooth of P. interruptus

Compare Dr. Benson's photograph to the Pliosaur tooth depicted in Owen's monograph.

Compare Dr. Benson’s photograph to the pliosaur tooth depicted in Owen’s monograph.

Picture Credit: Dr. Roger Benson (Oxford University)

Dr. Benson put his research into context, explaining:

“Pliosaurs were giant marine reptiles that could swim across oceans, specimens like the Dorking pliosaur show that this is true because similar fossils are also found in America”.   

The Importance of Regional Museums

Regional museums such as the the Dorking Museum and Heritage Centre house many fine specimens assisting in the preservation of an amazing geological and fossil record.  Research using some of the specimens from within these collections can help to shed light on the diversity and distribution of pliosaur genera.  Who knows, perhaps locked away in some cabinet, part of the prized fossil collection of another regional museum may lay the fossilised bones of another mislabelled specimen, one that could provide clues as to the why the Pliosauridae became extinct.

New Sail-Backed Dinosaur from Early Cretaceous Spain

Morelladon beltrani – A Spanish Sail-Backed Dinosaur

A team of Spanish scientists have published details of a new genus of plant-eating dinosaur which roamed the Iberian Peninsula about 125 million years ago (Early Cretaceous).  The dinosaur named Morelladon beltrani is believed to have been closely related to Iguanodon and the discovery helps to reinforce the belief held by many palaeontologists that the Ornithopoda were extremely diverse in Europe during this part of the Cretaceous.  The dorsal vertebrae have large, extended neural spines a feature seen in other Early Cretaceous Ornithopods, dinosaurs such as Ouranosaurus from Niger.  These spines may have supported a hump or perhaps a sail-like structure, the purpose of which remains open to debate.

An Illustration of Morelladon beltrani

An illustration of Morelladon.

An illustration of Morelladon.

Picture Credit: Universidad Nacional de Educación a Distancia (Spain)

This new species of dinosaur has been named from the fossilised remains of a single animal, preserved bones consist of dorsal vertebrae, the sacrum, partial ribs, the pelvic girdle, isolated teeth from the lower jaw and the right tibia.  However, despite a lack of cranial material, the team of scientists from the Spanish equivalent of the Open University (Universidad Nacional de Educación a Distancia) and the Autonomous University of Madrid (Universidad Autónoma de Madrid), identified eight unique anatomical features (autapomorphic features) that enabled a new genus to be established.

Elongated Neural Spines

One of the unique anatomical features identified were the very elongated and tall neural spines of the dorsal vertebrae.  Such features are known in other plant-eating dinosaurs, such as the Ouranosaurus (Ouranosaurus nigeriensis) from the Early Cretaceous of Africa and although Morelladon is related to Ouranosaurus, a phylogenetic analysis carried out by the Spanish team suggests that this new Spanish dinosaur is more closely related to other western European dinosaur taxa.  Dinosaurs such as Iguanodon (I. bernissartensis) from Belgium and Mantellisaurus atherfieldensis (from England).

The Extended Neural Spines of the Dorsal Vertebrae

A photograph of the fossil material and accompanying line drawing.

A photograph of the fossil material and accompanying line drawing.

Picture Credit: Universidad Nacional de Educación a Distancia (Spain)/PLOS One

The fossils come from a dig site within a quarry about five miles south-west of the city of Morella (Castellón Province), on the eastern coast of Spain.  The specimen was excavated from a red clay bed dated to the Upper Barremian age (125 million years ago), part of the Arcillas de Morella Formation.  The dinosaur’s name means “Morella tooth”, after the location of the fossil find and in keeping with the naming of Iguanodon, which itself means “iguana tooth”.  The trivial name honours quarry owner, Víctor Beltrán who has been prominent in the excavation and research of a number of Cretaceous vertebrates from this part of Spain.

The Fused Sacral Vertebrae of the Specimen (Sacrum)

The sacrum (fused vertebrae over the hips) of Morelladon.

The sacrum (fused vertebrae over the hips) of Morelladon.

Picture Credit: Universidad Nacional de Educación a Distancia (Spain)/PLOS One

Measuring up to six metres long and standing around 2.5 metres high at the hips, this new genus supports the hypothesis that the Iberian Peninsula in the Early Cretaceous was home to a large number of different types of Iguanodon-like herbivorous dinosaurs.

Why the Tall Neural Spines?

There have been a number of theories put forward to explain the presence of elongated neural spines in some types of dinosaur.  For example, one of the most famous of all the meat-eating dinosaurs – Spinosaurus had neural spines which supported a structure its back, often referred to as a “sail” that must have been more than two metres high.  The neural spines of Morelladon hint at a much smaller feature, around half a metre tall.  It has been proposed that since this dinosaur lived in a delta subject to distinct seasons the spines could have supported a fleshy hump where food reserves and fat could be stored to help the animal through leaner times.  Extant North American buffalo (Bison bison) have dorsal spines that support such structures.  The spines could also have supported a sail-like structure, perhaps this had a role in communication within the herd, or display.

Commenting on another potential purpose for the structure, Dr. Fernando Escaso (Universidad Nacional de Educación a Distancia) stated:

“The “sail” could have helped in heat exchange [thermoregulation] by releasing excess body heat into the environment as do the ears of the modern-day elephants.”

An effective heat exchanger would have been useful for such a large-bodied animal.  Everything Dinosaur team members suspect that oxygen isotope analysis from the many different types of teeth found in eastern Spain in Early Cretaceous rocks, would provide palaeontologists with a lot of information about the palaeoclimate.  For instance, some researchers claim that there was an annual average temperature range of thirty-six degrees with temperatures in excess of 40 degrees Celsius being recorded with annual lows of around 4 degrees C.

What are Styracosternan Dinosaurs?

Other media sources have cited the comment that Morelladon represents a new member of the styracosternan sub-group of the clade Iguanodontia.  What does this mean?  In the mid 1980’s it had become clear to many palaeontologists that the division of the Ornithopoda into large bodied forms such as Iguanodon and Dollodon and smaller forms such as Hypsilophodon was over simplistic.  A number of academics proposed new classifications of these bird-hipped dinosaurs, for example Paul Sereno (1986) proposed a new clade within the Ornithopoda called the Ankylopollexia “stiff thumbs”.  This clade included the Camptosaurs, Iguanodonts, Ouranosaurus and the hadrosaurids “duck-billed dinosaurs”.  This clade was further divided by Sereno et al (1986) into the Styracosterna, which included all the Ankylopollexia members with the exception of the camptosaurids (Camptosauridae family).

  1. Ankylopollexia = a clade of the iguanodontian dinosaurs
  2. Styracosterna = a clade of the iguanodontian dinosaurs the same as Ankylopollexia but with the camptosaurids excluded.

Therefore, the Styracosterna dinosaurs can be divided as a sub-group of the Iguanodontia clade that contains all the “duck-billed dinosaurs” and all the dinosaurs more closely related to them than to the Camptosauridae.

Phylogenetic relationships of Morelladon beltrani within the Iguanodontia Clade

Phylogenetic relationships of Morelladon beltrani with the Styracosterna.

Phylogenetic relationships of Morelladon beltrani with the Styracosterna.

Picture Credit: PLOS One with additional annotation by Everything Dinosaur

The diagram above shows how the Styracosterna fit into the clade Iguanodontia.   Phylogenetic analysis places Morelladon beltrani firmly in the with the styracosternan dinosaurs but more closely related to Western European iguanodonts such as Iguanodon bernissartensis and Mantellisaurus atherfieldensis than to other Iberian styracosternans such as Delapparentia turolensis and Proa valdearinnoensis.

Dog-sized Dinosaur and Chasing “Ghosts”

Hornless Hualianceratops wucaiwanensis

So details regarding  the dog-sized newest member of the Ceratopsia has been published in the on line academic journal PLOS One.  Say hello to Hualianceratops wucaiwanensis (pronounced as wal-lee-an-sera-tops woo-sigh-wan-en-sis), a small plant-eating dinosaur at the very foot of the dinosaur family tree that would lead to the mighty horned dinosaurs, animals such as Triceratops, Styracosaurus and Pachyrhinosaurus.

New Horned Dinosaur Without Any Horns

Hualianceratops illustrated.

Hualianceratops illustrated.

Picture Credit: Portia Sloan Rollings

Ever Expanding Horned Dinosaurs

Over the last ten years or so there have been a remarkable number of new genera of horned dinosaur erected, mostly representing Late Cretaceous Ceratopsians from North America.  Back in July, for example, Everything Dinosaur team members wrote an article about the latest edition to the Centrosaurine group of horned dinosaurs  Wendiceratops (W. pinhornensis).  The month before that, the other great Subfamily of the Ceratopsians, the Chasmosaurines got a new member (Regaliceratops peterhewsi).  Whilst there is undoubtedly lots of attention focused on the six metre plus, very ornate giants of North America, palaeontologists, as yet, don’t really understand how the horned dinosaurs evolved, or indeed, little is known about the phylogenetic relationships of some of the earliest forms.

Step into the frame Hualianceratops (the name translates as “ornamental face”), here’s a half metre long dinosaur that may shed some much needed light on Ceratopsian ancestry.  Ironically, Hualianceratops manages to hint at future fossil discoveries without providing a great deal of data about itself.

To read the article on Wendiceratops pinhornensisSouthern Alberta’s Wendiceratops

To read an article describing the discovery of Regaliceratops: New Horned Dinosaur Causes a Royal Rumble

The angular and the dentary (bones that form the lower jaw along with the predentary) have a roughened texture (rugose).  It is this rough texturing not known in any other basal Asian Ceratopsian that gives this little dinosaur its genus name.  The species or trivial name comes from the Chinese Wucaiwan “five colour bay” from the area in Xinjiang Province where the fossils were found.  The strata forms part of the famous Junggar Basin (Shishugou Formation).

Views of the Lower Jaw of Hualianceratops

The mandible of Hualianceratops wucaiwanensis (IVPP V18641)

The mandible of Hualianceratops wucaiwanensis (IVPP V18641)

Picture Credit: PLOS One

The picture above shows two photographs of part of the lower jaw of this little dinosaur, the angular bone (an) and the dentary (d) have a roughened texture.  The fossil material consists of the majority of the skull, plus some fused sacral vertebrae and portions of the lower limbs which include an almost complete left hind leg.  It is from these bones that the scientists have been able to deduce that Hualianceratops was a biped, moving around on its back legs, in contrast to the much larger, heavier and later North American Ceratopsians such as the famous Triceratops.

Post Cranial Fossil Material (Lower Limbs and Left Foot (Pes)

A partial hind limb and the left foot of Hualianceratops.

A partial hind limb and the left foot of Hualianceratops.

Picture Credit: PLOS One

The researchers behind the scientific paper, published this week in PLOS One, consist of a team from the University of Washington and from the Institute of Vertebrate Palaeontology and Palaeoanthropology, (IVPP), part of the Chinese Academy of Sciences.  These institutes have been collaborating since 2002, exploring numerous fossil sites in north-western China.  A number of early Ceratopsians have already been named as a result of this research programme.  The oldest known member of the horned dinosaur family Yinlong (Yinlong downsi) was found in the same Formation by these researchers.  It was formally named and described back in 2006.

An Illustration of Yinlong downsi Earliest Known Ceratopsian

Yinlong downsi, the earliest known Ceratopsian dinosaur.

Yinlong downsi, the earliest known Ceratopsian dinosaur.

Picture Credit: Everything Dinosaur

The newly described Hualianceratops would have looked very similar, but it was slightly shorter and stockier.  The bristles are speculative, no evidence of bristle-like structures have been found in association with Yinlong or Hualianceratops fossil material, as far as team members at Everything Dinosaur are aware, but if the related Psittacosaurs had such structures it can be speculated that these little dinosaurs also sported similar quills and bristles.  Both Yinlong and Hualianceratops, despite being classified as basal horned dinosaurs, did not have any horns.

The genus name Yinlong means “hidden dragon”, this does not reflect any great difficulties of extracting the fossil from the dig site, but merely pays homage to the fact that Xinjiang Province provided most of the location shots for the award winning Chinese film “Crouching Tiger, Hidden Dragon”.

Both Hualianceratops and Yinlong were found in the same fossil bed, although Yinlong’s location suggests that this animal lived before Hualianceratops evolved.  The age of the rocks in the Junggar Basin are difficult to date accurately, there is considerable debate as to the precise age of the strata, however, the rock layer from which these two dinosaurs were extracted has been dated to the Oxfordian age (Late Jurassic, approximately 163.5 to 157.3 million years ago).

Greater Diversity of Late Jurassic Horned Dinosaurs

The discovery of a new type of horned dinosaur from Upper Jurassic rocks provides evidence that as early as 160 million years ago, a number of Ceratopsia genera had already evolved.  These little hornless horned dinosaurs were much more diverse much earlier in geological time than previously thought.

Commenting on the discovery, Professor Catherine Forster, a biologist at George Washington University and co-author of the scientific paper on Hualianceratops, stated:

“Finding these two species in the same fossil bed reveals there was more diversity there than we previously recognised.  It suggests that the Ceratopsian dinosaurs already had diversified into at least four lineages [possibly five] by this time in the Jurassic Period.”

Looking for Ghosts

That’s really the significance of these fossil finds, prior to 2006, not a single Ceratopsian was known from the beginning of the Late Jurassic.  Although, the exact evolutionary path of the Ceratopsia remains unknown and the exact relationship between the likes of Yinlong, Hualianceratops and the closely related Psittacosaurus is unclear, because of these fossil discoveries and similar finds in China, palaeontologists can work out that there must be other early horned dinosaurs awaiting discovery.

Hualianceratops and the Ghosts (Ghost Lineages)

Hualianceratops and the ghost lineages..

Hualianceratops and the ghost lineages.

Picture Credit: PLOS One with additional annotation from Everything Dinosaur

Comparing the features of known early horned dinosaur fossils has led scientists to identify a number of “ghost lineages” in the early horned dinosaur family tree.  In this instance, when the family tree of these basal Ceratopsians is pieced together, the “best fit” that can be made indicates that there are a number of pieces missing.  These are ghost lineages, an evolutionary line that has no traces in the fossil record.  In simple terms, if the fossils of the “ghosts” have been preserved, then nobody has found them yet.

The researchers conclude that, based on the fossils that have been found at least five Ceratopsian lineages were present at the beginning of the Late Jurassic.

  1. Yinlong
  2. Hualianceratops
  3. The ghost lineage that led to the Psittacosaurs (dotted red line on the left of the picture)
  4. The ghost lineage that led to the later horned dinosaurs Chaoyangsaurus and Xuanhuaceratops (middle red dotted line)
  5. The ghost lineage that led to the evolution of the later Neoceratopsia (the red dotted line on the right)

Potentially, there are more “hidden dragon” fossils waiting to be found.  Perhaps, the name for the next basal horned dinosaur to be found from this part of north-western China will be inspired by another film, not “Crouching Tiger, Hidden Dragon” but “Ghostbusters”!

Isle of Skye Sauropods and Their Water World

Sauropod Tracks Suggest a Preference for Water

For much of the 19th and 20th Centuries, those behemoths of the Dinosauria, the Sauropods, were depicted as aquatic animals, at home in the deep water of large lakes, where their enormously heavy bodies could be supported by the water and their weak, peg-like teeth could cope with the soft and lush lakeside vegetation.  A substantial amount of evidence was put forward by scientists to support this hypothesis, not least of which was trackway evidence.  Most Sauropod tracks were associated with soft mud, the sort of conditions found close to large bodies of water.  Therefore, it seemed logical to depict these super-sized reptiles as animals at home in lacustrine (lakes), estuaries or riverine dominated habitats.  Thanks to some remarkable Middle Jurassic Sauropod footprints, this idea of long-necked dinosaurs preferring to live near to water might just be resurrected and find favour once again in palaeontological circles.

Dinosaur Tracks (Sauropoda) Discovered on the Isle of Skye

Sauropod tracks in hyporelief (Isle of Skye)

Sauropod tracks in hyporelief (Isle of Skye)

Picture Credit: University of Edinburgh/Scottish Journal of Geology

Went Out for An Ichthyosaur Came Back with an Ichnogenus!

A party of scientists from Edinburgh University in collaboration with local fossil experts were working on the northern part of the Isle of Skye conducting research into the fauna and flora preserved in strata that makes up the bay just south of the ruin of Duntulm Castle.  Although it is difficult to precisely date the vertebrate fossils found in these rocks, these sediments are believed to preserve evidence of life during the Middle Jurassic and since there are only a handful of highly fossiliferous sites dating from this time in geological history to be found anywhere in the world, the Isle of Skye represents an extremely important location for scientists.

Ironically, the team, which included Dr. Steve Brusatte from the School of GeoSciences (Edinburgh University), had set out to recover some Ichthyosaurus fossils but the area where the marine reptile lay remained covered by the high tide.  Although disappointed, the team continued to document the variety of fossils located on the foreshore and as the light from the relatively low sun cast shadows along the rocky coastline, Dr. Brusatte and his colleague Dr. Tom Challands came across some large lumps of raised rock.  Protruding from one lump of rock were extensions of the material that gave the distinct impression of digits and substantial claws, particularly on digits I and II.  This pattern is diagnostic of the hind footprint from a Sauropod dinosaur.

The Left Hind Foot (Pes) of a Sauropod Dinosaur Isle of Skye

a = dorsal view, whilst b = anterior view, the digits are marked.  Lens cap = 5 cm.

a = dorsal view, whilst b = anterior view, the digits are marked. Lens cap = 5 cm.

Picture Credit: University of Edinburgh/Scottish Journal of Geology

The picture above shows one of the rear feet of the Sauropod (left pes), the digits are marked and the lens cap, in the picture to provide scale, measures five centimetres in diameter.  The prints are in hyporelief (convex and raised).  The tracks were found in three beds in total (bed 34 and 35 provided trackways, whilst bed 9 provided single prints identified as those from a Sauropod plus additional individual tridactyl prints identified as having been made by a large Theropod.

The footprints, the largest of which is around seventy centimetres in diameter were made by animals that were around fifteen metres in length and weighed in excess of ten tonnes.  The tracks are the first Sauropod tracks to be found north of the border and represent the largest dinosaur known from Scotland.

Long-Necked Dinosaurs Walking Across a Salt Water Lagoon

The beds from which the prints come from also contain shark teeth, and the remains of marine molluscs.  The strata does not exhibit any signs of mud cracks or drying out, so this evidence, along with the associated fossils, suggests that the Sauropods were wading across a shallow salt water lagoon.  Although an ichnogenus has yet to be assigned to these tracks, the University of Edinburgh research team have proposed that the prints are similar to the ichnogenus Breviparopus or perhaps Parabrontopodus.

Sauropod Tracks Discovered on the Isle of Skye

Concave epirelief trackways in bed 35 (Isle of Skye).

Concave epirelief trackways in bed 35 (Isle of Skye).

Picture Credit: University of Edinburgh/Scottish Journal of Geology

If you examine the picture above carefully, you can see that despite the size of the prints, they are quite close together.  The footprints of Titanosaurs for example, tend to be much wider apart.  These are “narrow gauge” prints perhaps indicative of a cetiosaurid or a diplodocid dinosaur.

Implications for the Habits of Sauropods

As Sauropod prints are found in three different beds it could be suggested that these dinosaurs were frequent visitors to this sort of salt water habitat.  Although, it has to be pointed out that it is difficult to determine how much time elapsed between the deposition of the different beds.  The strata could have been laid down over a few centuries or there could be thousands of years between these bedding planes.  One thing that the scientists can be fairly confident about is that between some of the beds in this area there are large concretions of limestone.  The algae and other micro-fossils such as dinoflagellate and preserved palynomorph fossils indicate that these sediments date from the Bathonian age (167.7 to 164.7 million years ago approximately).

A Line Drawing of Some of the Epirelief Prints Showing the “Narrow Gauge” of the Dinosaur Tracks

A line drawing of the Sauropod trackways from bed 35.

A line drawing of the Sauropod trackways from bed 35.

Picture Credit: University of Edinburgh/Scottish Journal of Geology

Dr. Challands described the moment when the team became aware of the significance of their discovery as an “epiphany”.  Details of the tracks have been published in the “Scottish Journal of Geology” and these trackways and others like them found elsewhere in the world (including England), have led some palaeontologists to re-examine the evidence for Sauropods being entirely terrestrial animals.  The researchers writing in the journal state:

“The Skye site presents a confluence of evidence for Sauropods living in the region of a submerged lagoon over multiple generations.”

Why Live Close to Salt Water?

There might have been a number of advantages for the Sauropods if they lived close to large bodies of water, for example:

  • Sandy beaches would have made natural thoroughfares for these large creatures providing access to the edge of forests adjacent to the shoreline.
  • Open areas would have limited the chances of these plant-eating dinosaurs being ambushed by Theropods.
  • Lagoons are associated with abundant food supplies.
  • By wading or wallowing in the water these creatures would have been able to cool their large bodies very effectively.
  • The salt water and mud would have provided relief from biting insects.
  • Few predators would have been prepared to venture out into the lagoon to hunt the Sauropods.

The Isle of Skye in the Middle Jurassic

The Isle of Skye (Bathonian faunal stage).

The Isle of Skye (Bathonian faunal stage).

Picture Credit: Jon Hoad

The illustration above shows two Sauropods on the mud flats of the lagoon, whilst in the foreground a small, Theropod (Ornitholestinae Subfamily) looks on warily.

A Significant Middle Jurassic Discovery

Commenting on the trace fossils and their importance to palaeontology, Dr. Brusatte stated:

“The Middle Jurassic was a really interesting period in the history of life, when there was a whole lot of evolution going on. What is really frustrating is that we have a lot of fossils from different places with fossils from the Early Jurassic and the Late Jurassic, but there is relatively little fossil-bearing Middle Jurassic rock around.”

The Isle of Skye fossils pose some intriguing questions, these tracks most likely were made by primitive Sauropods at a time when the Sauropoda were beginning to radiate, differentiate and evolve into a number of new forms.  In addition, the strata preserves evidence of multiple generations of Sauropods inhabiting lagoonal environments, which suggests the intriguing possibility that these huge creatures might have sought out such habitats, preferring them to inland areas.

Do these tracks preserve evidence of Isle of Skye Sauropods and their water world?

The Jehol Biota and Sea Turtle Origins

Scientists Use Chinese Cretaceous Turtle Fossils to “Crack” Turtle Evolution

Turtles and tortoises are representatives of a very ancient group of reptiles and scientists have much still to learn about their origins and how the Chelonia (the name given to tortoises, turtles and terrapins) evolved, but new research by a joint German, Hungarian and Chinese research team is helping to shed some light on these shelled creatures.  The scientists have been studying the beautiful, fossilised remains of Early Cretaceous turtles from north-eastern China in a bid to determine how the first sea turtles arose.

The extant sea turtles found today, represent just a tiny portion of what was once, a hugely diversified group.  There are just seven species, the majority of which are very vulnerable to extinction.  The first sea turtle fossils appear in Cretaceous aged rocks some 130 million  years old, it is very likely that these marine animals evolved from a common, freshwater ancestor, although this ancestor has yet to be identified.  In this new study, Dr. Chang-Fu Zhou of the Shenyang Normal University of Liaoning and Dr. Márton Rabi of the Biogeology Workgroup of the University of Tübingen and the Hungarian Academy of Sciences tried  to identify the ancestors of modern sea turtles from amongst the many excellent turtle fossils that represent the famous Jehol Biota of the Early Cretaceous of north-eastern China.

An Example of One of the Exquisitely Preserved Turtle Fossils Affiliated to the Jehol Biota

The newly-described fossil species, Xiaochelys ningchengensis, from northeastern China’s Jehol Biota; right: an illustration of the skeleton incorporating positive and negative impressions preserved in the layers of stone

The newly-described fossil species, Xiaochelys ningchengensis from north-eastern China’s Jehol Biota; right: an illustration of the skeleton incorporating positive and negative impressions preserved in the layers of stone.

Picture Credit: Chang-Fu Zhou

The picture above shows the slab and counter slab of the newly described Cretaceous turtle Xiaochelys ningchengensis from north-eastern China.  To the right of the photograph a line drawing has been produced to show the preserved features of the shell (scale bar = 20 mm).

The Importance of the Jehol Biota

The Jehol Biota is a rich Cretaceous ecosystem preserved in a multi-layered rock formation cropping out in the Chinese provinces of Liaoning, Hebei and Inner Mongolia.  The habitat represented is that of a temperate forest zone, with large lakes in situ.  Nearby, volcanoes occasionally covered the area in fine ash and this led to the exquisite preservation of many of the fossils to be found in these regions.  The most famous fossils associated with these strata are feathered dinosaurs, animals such as Sinosauropteryx, Sinornithosaurus, Microraptor and the recently described  Zhenyuanlong suni.

To read an article about the significance of the Jehol Biota: Unravelling the Sequence of Deposition in North-eastern China

To read an article about the “winged dragon”  Zhenyuanlong suniA New “Winged Dragon” from China

North-eastern China Around 130-125 Million Years Ago

A rich and diverse Jurassic environment dominated by small mammals, Pterosaurs and feathered Theropods.

A rich and diverse environment dominated by small mammals, Pterosaurs and feathered Theropods.

Picture Credit: Julia Molnar

Ironically, despite this part of the world’s connection with feathered dinosaurs, the first vertebrate of the Jehol Biota to be described was a freshwater turtle (1942).

Xiaochelys ningchengensis – A New Species of Freshwater Turtle

The research team have described a new species of freshwater turtle, adding to the rich vertebrate assemblage known to have existed in this part of the world during the Early Cretaceous.  A study of the fossils of X. ningchengensis was undertaken to ascertain whether this ancient turtle, whose shell was not much bigger than a saucer, was a potential ancestor of today’s sea turtles.  Dr. Zhou and Dr. Rabi applied comparative morphological assessment techniques to try to map this turtle’s position in relation to other members of the Chelonia, this produced a comprehensive phylogeny diagram of turtle evolutionary relationships leading to today’s living turtle species.  The scientists wanted to test an earlier hypothesis that the Jehol Biota turtles belong to a lineage that eventually gave rise to extant marine reptiles.

Dr. Zhou explained:

“According to our findings, the Jehol turtles are instead found on the lineage leading to the Cryptodiran turtles.”

An Illustration of Xiaochelys ningchengensis

An illustration of the freshwater turtle Xiaochelys

An illustration of the freshwater turtle Xiaochelys

Picture Credit: W. S. Wang

In the picture above, the small, freshwater turtle Xiaochelys ningchengensis has caught a fish (Lycoptera spp.) fossils of these fish are associated with the same strata as the X.  ningchengensis material.  Xiaochelys (pronounced sho-ow-key-lis) comes from the Chinese Pinyin “Xiao” a reference to the small size of this taxon and the Greek for turtle “chelys”.  The trivial name honours the type locality, Ningcheng County (Inner Mongolia).  The research has been published in the latest edition of the academic journal “Scientific Reports”.

The Cryptodires, which also include sea turtles, are able to pull their heads and necks vertically into their shells using an S-shaped motion.  The statistical analysis only just placed the likes of Xiaochelys outside the ancestral line of modern turtles, so it is quite likely that this Cretaceous turtle was quite similar to those types of turtle that were ancestral to the modern forms.

Dr. Zhou added:

“These well-preserved fossils give us insights into the origin of Cryptodires.  About three-quarters of today’s turtles belong to that group.”

It is not clear however, just how the main adaptations of marine turtles arose.  These evolutionary changes included the reduction of their skeleton and the development of large, rigid paddles which enable the creatures to swim in a style which is best described as “flying underwater”.  The Chelonia, throughout their long evolutionary history seemed to have evolved into a myriad of forms with several lineages “flipping” between a terrestrial and fully aquatic existence.  Scientists still don’t really understand how the Chelonia evolved and changed since they first appeared many millions of years ago.

Everything Dinosaur acknowledges the help of Tübingen University in the compilation of this article.

Renowned Palaeontologist Jack Horner Will Join Chapman University as Presidential Fellow

John “Jack” Horner to join Chapman University (California)

John R. “Jack” Horner, one of the world’s leading experts in palaeontology, MacArthur “Genius” Grant recipient and inspiration for the character of Alan Grant in the “Jurassic Park” movies, will join Chapman University in Orange, California as a Presidential Fellow, beginning in the autumn of next  year . He retires on June 30th, 2016 from a distinguished thirty-three year tenure as Regents Professor of Palaeontology at Montana State University and curator of palaeontology at the Museum of the Rockies (Bozeman, Montana).

John “Jack” Horner – To Join Chapman University

A new appointment for the distinguished palaeontologist.

A new appointment for the distinguished palaeontologist.

Picture Credit: Chapman University

Commenting on the appointment, Dr. Daniele Struppa, Chancellor and President-designate of Chapman University stated:

“I am delighted to announce that Jack Horner, one of the most creative living scientists, will join us as a Presidential Fellow in the next academic year.  We are not hiring Jack for our acclaimed film programme, nor for a palaeontology programme – we don’t have one – but rather for his unconventional and extremely successful approach to creativity and learning.  It is his ingenuity and his sense of curiosity and wonder that he will bring to Chapman as we continue to re-think the meaning of education and how students learn.”

For Horner, as he will be seventy when he takes up the appointment, the warmer climate in California might have helped tip the balance.  He will most certainly be missed after his remarkable career in Montana.  Everything Dinosaur reported on his retirement announcement back on the 18th of this month: Jack Horner Announces His Retirement (Well Almost)

With his tremendous energy and enthusiasm, he will be taking on a number of new challenges.  Speaking about his new role, he explained:

“I’m coming to Chapman because of its strong commitment to nurturing curiosity, inquisitiveness and creativity in all aspects of academia,  I very much look forward to helping Dr. Struppa and his staff create an integrative educational environment that accepts all learning styles.”

Looking Forward to the New Challenge

Last month, Horner spoke at Chapman University’s first annual Dyslexia Summit: Strength in Cognitive Diversity, where he recounted his inspirational life story.  As a child with undiagnosed dyslexia, he struggled in school and later dropped in and out of college, attending the University of Montana for seven years.  Although he never completed a formal degree, the University of Montana awarded him an honorary doctorate of science in 1986 due to his astonishing list of achievements in the field of palaeontology.

Among other ground-breaking accomplishments, Horner and his teams discovered the first evidence of parental care in dinosaurs, extensive nesting grounds, evidence of gigantic dinosaur herds, and the world’s first dinosaur embryos.  Horner’s “outside the box” thinking skills led him to ask why no one had thought yet of slicing open fossilised dinosaur eggs – and the result was the discovery of the delicate embryos, fossilised in place.  He was a leader in the now-widely-accepted theory that dinosaurs were warm-blooded, social creatures more like birds than cold-blooded animals like lizards.

Helping to Popularise the Study of the Dinosauria

Horner has named several new species of dinosaurs, including Maiasaura, the “good mother reptile.”  Three dinosaur species have been named after him.  He has published more than a hundred professional papers, eight popular books and fifty popular articles.   His book “Digging Dinosaurs” was lauded by New Scientist magazine as one of the two hundred most important science books of the 20th century.

Horner was the technical advisor for Steven Spielberg on all four movies in the “Jurassic Park” franchise, including this past summer’s global hit “Jurassic World”.  He also helped inspire the lead character Alan Grant, portrayed by actor Sam Neill in the first and third films.

Awarded the famed MacArthur “Genius” Grant in 1986, Horner has received many other honours and awards.  Most recently, in 2013, he was awarded the Romer-Simpson Medal, the highest honour given by the Society of Vertebrate Palaeontology, for his lifetime of achievement in the field.  Earlier this year, he was recognised as one of the world’s top twenty-four scientists by Newton Graphic Science magazine.

Everything Dinosaur acknowledges use of the press release from Chapman University as supplied by Mary Platt (Director of Communications and Media Relations) in the compilation of this article.

“Fanged Eels” and “Fire Frogs” of the Permian

“Fanged Eels” and “Fire Frogs” of the Permian

An international team of scientists led by researchers from the Field Museum of Chicago (USA) and the Natural History Museum (London), have unearthed an large number of vertebrate fossils that provide an insight into the fauna that existed in a huge, lowland swamp that covered a part of the southern portion of the ancient super-continent Pangaea.  The fossils are extremely significant as most of what palaeontologists know about life on Earth some 278 million years ago comes from fossils found in North America and Europe.  Vertebrate fossils from South America dating from the Artinskian faunal stage of the Early Permian are extremely rare.

Amongst the significant fossil finds, the scientists writing in the journal “Nature Communications” describe fanged eel-like amphibians, hunters with huge mouths that resemble giant salamanders and a reptile which was previously unknown from South America.

A Bizarre Watery World Dominated by Amphibians

Evidence of the fauna of Brazil some 278 million years ago has been unearthed.

Evidence of the fauna of Brazil some 278 million years ago has been unearthed.

Picture Credit: Andrey Atuchin

The large lakes and swamps were home to an ancient ecosystem that was like nothing around today.  Amphibians dominated this watery world and these newly described fossils from the Parnaiba Basin of north-eastern Brazil provide a detailed record of the fauna that was present in the southern part of Pangaea close to the tropics.

Commenting on the discoveries, one of the authors of the report, Chicago Field Museum scientist Ken Angielczyk stated:

“Almost all of our knowledge about land animals from this time, comes from a handful of regions in North America and western Europe, which were located near the equator.  Now we finally have information about what kinds of animals were present in areas farther to the south, and their similarities and differences to the animals living near the equator.”

For example, the lizard-like creature named Captorhinus aguti was previously known from fossils found in  the south-western United States, this research extends this animals faunal range by a considerable margin.

The Early Reptile Captorhinus aguti

A resident of Brazil - Captorhinus.

A resident of Brazil – Captorhinus.

Picture Credit: Field Museum (Chicago)

This reptile reached lengths of around half a metre, it had batteries of crushing teeth and it has been suggested that this Eureptile was probably herbivorous.

Fanged Eel-Like Amphibians

The fanged amphibian is a new species, it has been named Timonya annae.  Measuring up to forty centimetres in length, this amphibian has been described as a cross between a freshwater eel and a Mexican salamander.  Although capable of moving around on land, it was very much at home in the water where it hunted small fish, other amphibians and invertebrates.

A Close up of the Newly Described Permian Amphibian Timonya annae

A fanged amphibian from the Early Permian.

A fanged amphibian from the Early Permian.

Picture Credit: Andrey Atuchin

Lurking in the background of the picture above is a large, predatory amphibian, a member of the Rhinesuchidae family.  As far as we at Everything Dinosaur are aware, the genera or  species has not been identified within the scientific paper.  It would have been one of the top aquatic predators in the lake system perhaps reaching lengths in excess of 1.2 metres.

The Beautifully Preserved Skull of Timonya annae

A close up of the Timonya skull.

A close up of the Timonya skull.

Picture Credit: Juan Cisneros

 Fire Frogs

The other new species of amphibian has been named Procuhy nazarienis (pronounced pro-coo-ee naz-ar-ee-en-sis), the name means “fire frog” in the native Timbira language of this part of Brazil.  It was closely related to T. annae and the name was inspired by the Pedra de Fogo Formation (Rock of Fire), where the fossils were found.  The strata in the Lower Pedra de Fogo Formation (the stratigraphic zone that contains the fossils), is well known as it contains flints which were used to make fires.  The term “frog” is also misleading, these amphibians were not closely related to extant frogs or indeed to that branch of the Amphibia that gave rise to the frog lineage.

Everything Dinosaur acknowledges the contribution of the Field Museum in the compilation of this article.

Dakotaraptor Compared to Utahraptor

Dakotaraptor Compared to Utahraptor

The vast majority of the dromaeosaurids known were actually rather small when compared to other types of Theropod dinosaur.  As a group, these active dinosaurs were geographically widespread with fossil specimens found in Asia, both North and South America and even England (Nuthetes destructor).  All species described to date were predatory and they certainly seemed to have been amongst the most adaptable of all the Theropoda.  Over the last few years our view of these feathered terrors has changed.  They are no longer confined to the role of swift cursorial (running) hunters, scientists have proposed that many members of the Dromaeosauridae were excellent climbers (scansorial), tree dwellers (arboreal) and that a number of them were volant (capable of powered flight or gliding).

Dromaeosaurids like Changyuraptor Seemed to have Filled a Variety of Ecological Niches

"Four winged" terror

“Four winged” terror

Picture Credit:  S. Abramowicz

The illustration above depicts the dromaeosaurid Changyuraptor yangi from Liaoning Province (China), it was very probably capable of flight.

Giant Raptors – Gigantism in the Dromaeosauridae

Over the dromaeosaurids long evolutionary history, gigantic forms did evolve and we suspect that Cretaceous-aged strata still hold the undiscovered remains of a number of super-sized dromaeosaurids.  With the naming and describing of Dakotaraptor (D. steini), the Hell Creek Formation can now boast a gigantic sized raptor amongst its faunal members.  At around five and a half metres in length Dakotaraptor was a sizeable beast, but for the moment, the dinosaur called Utahraptor (U. ostrummaysorum) which roamed what was to become the State of Utah more than fifty million years before Dakotaraptor evolved, is regarded as the largest.

Direct comparisons are difficult, the two individuals that represent Dakotaraptor (a gracile form and a more robust specimen) are known from only fragmentary remains, limb bones, vertebrae including caudal vertebrae, for example.  The holotype of Utahraptor is also fragmentary, consisting of some cranial material, a tibia and caudal vertebrae.  Some further fossil material assigned to Utahraptor has come to light since Utahraptor ostrummaysorum was formally named and described, but even so, direct comparisons between these two North American giants is difficult.

Comparing Claws

Ironically, there is one part of these two dinosaurs that we can compare and contrast.  The famous sickle-toe killing claw, what is termed the pedal ungual II.

The Sickle-Toe Claws of Utahraptor and Dakotaraptor Compared

Comparing those "killer claws".

Comparing those “killer claws”.

Picture Credit: Robert DePalma with additional annotation by Everything Dinosaur

In the photograph above, a cast of the second toe claw of Utahraptor (left) is compared to that of Dakotaraptor (right).  The claws are very similar in size, although the degree of curvature is different.  In addition, Dakotaraptor had a more pronounced flexor tubercle (the ringed area in the photograph).  This would suggest that the second toe claw of Dakotaraptor was highly mobile dorsoventrally (it could be moved up and down really well).  This might indicate that Dakotaraptor, already nick-named D-raptor, was more capable of slashing with its second toe and with some considerable force too.

When the proposed femur to tibia bone ratios are compared between Utahraptor and Dakotaraptor, it can be seen that D. steini had body proportions very similar to the much smaller dromaeosaurids such as Dromaeosaurus.  Utahraptor’s hind legs seem to have been more robust and as a result Utahraptor may have been a heavier animal, but in a sprint Dakotaraptor probably had the edge.  Both dinosaurs could very probably outrun even the most talented athlete.

The presence of this new predator expands the record of Theropod diversity in Late Cretaceous Laramidia, adding a new dimension to the ecology and food chains that likely occurred in North America towards the end of the Mesozoic.

Why Dakotaraptor steini?

The genus name translates as “robber or thief from Dakota”, whereas the trivial name honours American palaeontologist Walter W. Stein.

Eggshells Tell Scientists About Dinosaur Body Temperatures

Endotherms or Ectotherms the Debate Gets “Egg-citing”

The debate as to whether dinosaurs were warm-blooded (endothermic) like mammals and birds or cold-blooded (ectotherms) like crocodiles and lizards, has taken a further twist with the publication of a study published in the journal “Nature Communications”.  Scientists have used a new method to chemically analyse dinosaur eggshells which has helped them gauge the long extinct animal’s body temperature.  Armed with this data and an estimate of the temperature of the surrounding environment, the researchers can postulate about whether dinosaurs had high metabolic rates and active life-styles or whether like alligators and lizards they tended to be only capable of short bursts of activity.

The team’s findings suggest that dinosaurs were neither true endotherms or completely ectothermic, but somewhere in between – mesotherms.  In addition, as two different types of dinosaur produced different results, this new study indicates that body temperature differed between dinosaur genera.

Research Suggests that Oviraptorid Dinosaurs were Mesothermic

"Conch Thief" feeding by the lake shore.

Not warm-blooded or cold-blooded but somewhere in between.

The conclusions drawn by the scientists are similar to those made by a team of American researchers who reported in 2014.  Following an extensive analysis of the histology and ontogeny of fossilised bones (analysis of bone cells and growth) these scientists concluded that dinosaurs were probably mesotherms.

To read more about the 2014 research: Goldilocks and Dinosaurs the warm-blooded/cold-blooded Debate

Why All the Fuss?

The argument as to whether the Dinosauria were endothermic or ectothermic has raged for over 150 years.  It was once thought that dinosaurs were slow-moving, sluggish, very lizard-like creatures.  They had to bask in the sun or rely on other external sources of heat to help warm their bodies before they could become active.   This meant that they were probably not very active at night, it also suggested that they had similar life-styles to extant reptiles such as crocodiles, snakes and lizards.  These creatures can be very mobile, but only for short periods and they soon become tired.  Thomas Henry Huxley (1825-1895), was one of the first scientists to challenge this view.  He argued that birds and dinosaurs were closely related.  In the 1960’s there was a revolution in thinking with regards to dinosaurs.  John Ostrom’s work on the Theropod dinosaur Deinonychus led to dinosaurs being depicted as much more agile, fast-moving animals.  Ostrom produced carefully argued and extremely detailed studies on dinosaur biology and anatomy and he depicted them as much more bird-like creatures capable of complex behaviour – more reminiscent of today’s mammals than like today’s reptiles.

Dynamic Dinosaurs – Active and Agile Animals

Robert Bakker (student of John Ostrom) championed the agile, active dinosaur theory.

Robert Bakker (student of John Ostrom) championed the agile, active dinosaur theory.

Robert Bakker, a student under the tutelage of Ostrom developed these ideas further and portrayed dinosaurs as warm-blooded creatures, it was Bakker who produced the famous illustration of Deinonychus shown above and it was Bakker who influenced a lot of thinking regarding the Dinosauria with his ground-breaking book “The Dinosaur Heresies”, which was published in 1986.

A Study of Rare Isotopes 

The research team utilised a pioneering procedure which allows the internal temperature of female dinosaurs to be plotted by analysing the behaviour of two rare isotopes found in calcium carbonate, a key ingredient in eggshells.  A total of nineteen dinosaur eggs were included in the study, they represent two very different types of dinosaur.  Eggshells from Argentina came from a large Titanosaur (Sauropoda), the eggshells collected in the Gobi desert, Mongolia, represent fossils from a small Theropod dinosaur, an oviraptorid.  The isotopes oxygen-18 and carbon-13 tend to cluster together at colder temperatures.  The amount of clumping enabled the scientists to calculate the body temperature of the mother.  Chemical analysis of the surrounding rock matrix permitted the researchers to estimate the temperature of the palaeoenvironment at around the time the eggs were laid.

The analysis of these eggshells, all of which were collected from Upper Cretaceous strata, suggest that the Titanosaur’s body temperature had been around 38 degrees Celsius at the time of laying.  This is a little higher than our own internal body temperature (37 degrees Celsius).  The implication is that the Titanosaur had an internal body temperature similar to that of a endotherm, although it has to be considered that the huge gut of this giant herbivore, essentially an enormous, heat-producing digestive vat would probably have influenced the internal temperature.  The sheer size of the animal, volume compared to surface area, would have probably helped it to maintain a relatively constant body temperature.  Thermo-regulation for such large animals is not so much as trying to keep warm, heat loss from a large body is much less severe than with a small animal, for example.  In the case of the Titanosaurs, once they warmed up they probably stayed warm for a very long time, keeping cool could have been more of a problem (that’s why African elephants have big ears).

Typical Titanosaur Eggs

An example of Titanosaur fossil eggs.

An example of Titanosaur fossil eggs (Hypselosaurus).

Picture Credit: Everything Dinosaur

The results from the much smaller oviraptorid paint a different picture.  These dinosaurs were very closely related to birds, but the body temperature plotted is much lower than an endotherm.  The scientists calculated that the Theropod had an internal temperature of around 32 degrees Celsius, but this was at least six degrees warmer than the environment.  This suggests that oviraptorids, dinosaurs that were closely related to birds were able to raise their body temperatures above that of their surroundings.

Commenting on these results, lead author Robert Eagle (University of California Los Angeles) stated:

“The temperatures we measured suggest that at least some dinosaurs were not fully endotherms [warm-blooded] like modern birds.  They may have been intermediate, somewhere between modern alligators and crocodiles and modern birds”.

This study supports the idea that dinosaurs could produce heat internally and raise their body temperature higher than their surrounding environment, but they were unable to maintain this temperature at a consistent level like a mammal or a bird (endotherms).  The scientists conclude that if the dinosaurs were mesothermic, they were probably more active than alligators but not as active as birds or mammals.  The international research team state that they could not observe any strong evidence either for ectothermy or endothermy in the species examined.  The body temperatures calculated for the Titanosaur and the oviraptorid indicate that variable thermoregulation likely existed among non-avian dinosaurs and that not all dinosaurs had body temperatures in the range of that seen in extant birds.

Link to an article published in June 2015, that postulates that the Dinosauria were endothermic: Dinosaurs were Warm-blooded Debate Hots Up

The Hands and Feet of Homo naledi

Two New Papers Published on Homo naledi

Two new papers on the latest hominin to be added to the human family tree have just been published in the academic journal “Nature Communications”.  Less than one month has passed since Everything Dinosaur blogged about the amazing fossil finds in the Rising Star Cavern, part of a cave system located in an area known as the Cradle of Human Kind close to Johannesburg.   Researchers from the Evolutionary Studies Institute (University of Witwatersrand), in association with National Geographic, the Department of Science and Technology and the National Research Foundation of South Africa announced the discovery of a new species of hominin – Homo naledi.  These papers focus on the anatomy of the hands and feet respectively, but why the fascination with the fingers and toes of this South African species?  The explanation is simple, the hands and feet can provide scientists with valuable information as to how human H. naledi may actually have been.

The Hand and Foot of Homo naledi

The hand and the foot of Homo naledi.

The hand and the foot of Homo naledi.

Picture Credit: Peter Schmid and William Harcourt-Smith, Wits University

Good at Climbing but also Adapted for Bipedal Walking

The papers reflect just how remarkable the discovery of Homo naledi was.  The first point to make is that palaeoanthropologists do have a lot of bones to study.  In total, some 1,550 numbered fossil elements have been retrieved from the difficult to access cave.  Taken together these two papers indicate that this human-like creature, was uniquely adapted to both an arboreal existence (tree climbing) and walking on the ground.  In addition, the structure of the bones in the hand suggest that these hominins were capable of intricate hand movements and precise manual manipulation.

The titles of the two papers, state precisely what they are about, full marks to the research team for their brevity.  No long-winded titles here, these papers do “exactly what it says on the tin.”

  1. The foot of Homo naledi
  2. The hand of Homo naledi

The research were conducted by a team of international scientists associated with the Evolutionary Studies Institute at the University of the Witwatersrand in South Africa, home of the Rising Star Expedition team that made the 2013-discovery at the Cradle of Human Kind.  According to the researchers, when considered together, these papers indicate a decoupling of upper and lower limb function in H. naledi, and provide an important insight into the skeletal form and function that may have characterised early members of the Homo genus.  An evolutionary tree that eventually led to our own species Homo sapiens.

The foot of Homo naledi

Lead author, of the paper published on the pes (foot), William Harcourt-Smith and his colleagues describe the H. naledi foot based on 107 foot bones recovered from the floor of the Denaldi Chamber (Rising Star), including a well preserved adult right foot.  They show the H. naledi foot shares many features with a modern human foot, indicating it is well-adapted for standing and walking on two feet (bipedalism).  However, there are differences from the bones found in the foot of a Neanderthal, or our own feet for that matter.  For example, the authors note that the Homo naledi foot differs in having more curved toe bones (proximal phalanges) and the arch of the foot is not so pronounced.

The hand of Homo naledi

Lead author, of the paper that describes the hand, Tracy Kivell (University of Kent) and her colleagues describe the hand of Homo naledi based on an assessment of approximately 150 hand bones from the cave.  One of the key finds was a nearly complete adult right hand (manus), it was missing one small bone in the wrist.  This is an exceptionally rare find in the human fossil record.  As the tiny toe and finger bones were found in a number of cases in almost perfect articulation, this rules out the possibility of water having run through the cave at some point after the bodies came to be at that location.  Running water would have scattered the bones but the scientists found this not to be the case.  It is likely that the bodies have remained undisturbed, this suggests that the corpses may have been deliberately placed in this part of the cave system.  For such a small-brained hominin to show care for the deceased is very unexpected and more research is required to date the fossils and to try to understand how the remains of at least fifteen individuals came to be in the cavern.

The Delicate Finger Bones Preserved in Articulation in the Cavern

The hand of Homo naledi

The hand of Homo naledi

Picture Credit: Marina Elliott

The H. naledi hand reveals a unique combination of anatomy that has not been found in any other fossil human before.  The wrist bones and thumb show anatomical features that are shared with Neanderthals and humans and suggest powerful grasping and the ability to use stone tools.  The thumb is particularly robust, this is a trait only found in recent hominins.

However, the finger bones are more curved than most early fossil human species, such as Lucy’s species Australopithecus afarensis, suggesting that H. naledi still used their hands for climbing in the trees.  This mix of human-like features in combination with more primitive features demonstrates that the H. naledi hand was both specialised for complex tool-use activities, but still used for climbing locomotion.

Commenting on the significance of the Homo naledi hand, Dr. Kivell stated:

“The tool-using features of the H. naledi hand in combination with its small brain size has interesting implications for what cognitive requirements might be needed to make and use tools, and, depending on the age of these fossils, who might have made the stone tools that we find in South Africa.”

Age is the Key

More research will be carried out into this remarkable South African fossil discovery.  The key question is determining the age of the fossils.  Obtaining an accurate date for Homo naledi would help palaeoanthropologists place this species within the human lineage.  For example, this could be a tool-using, human-like creature that lived some three million years ago, or perhaps a more recent member of the hominin family, a human-like creature that retained some ancient Australopithecine traits that survived until much more recently.  This latter scenario is not that far-fetched, discoveries on the Indonesian island of Flores stunned the world of anthropology when it was revealed that a dwarf species of human (Homo floresiensis) had lived on the heavily forested island until, perhaps, as recently as 12,000 years ago.

The paper on the hand, opens up a debate amongst scientists.  The hand looks capable of intricate manipulation, indicating tool usage, but the brain of Homo naledi is estimated to have been not much bigger than a chimps.  If the hypothesis is correct, that the use of tools changed the shape of the bones in the hand, then the implication is that a small-brained hominin was making and using complex tools.  Comparing the hand anatomy to our own species and to that of the Neanderthal (H. neanderthalensis), Dr. Kivell commented

“They [Neanderthals and humans] make tools, complex tools, and use them all the time, enough so that it’s actually changed their morphology.  Perhaps naledi was using tools that were made out of different materials or doing some other forceful, precision-grip manipulations, but the most straight-forward explanation is that naledi is making and using tools.”

This may be the most straight forward explanation but there may be other reasons why those hands are so human-like.  Analysis of the teeth will provide a detailed picture of the diet of these creatures.  If, as has already been proposed that they were largely vegetarian, then the hands could have evolved grasping and manipulation traits to help them search for seeds, to pluck fruits and to hold small items of food.  Clearly, the Rising Star fossils will provide scientists with a unique opportunity to learn more about hominin evolution.  Now, if we can only get an accurate date…

To read about the cave discovery: Homo naledi A New Species of Hominin from South Africa

Everything Dinosaur acknowledges the help and assistance of the media team at the University of Witwatersrand in the compilation of this article.

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