Fossil Finds

[rogue06]

The discovery of yet another intersting dinosaur nest has been announced. This one, approximately 70 myo (Late Cretaceous) and from the red sandstone deposits of the Baruungoyot Formation in the Nemegt Basin of southern Mongolia, includes an oviraptorid theropod brooding on the nest.

When first discovered in the 1920s an oviraptor was found upon a nest of eggs but was thought to be stealing them for food (oviraptor means "egg thief"). Many years later it was realized that the eggs probably belonged to the oviraptor.

The discovery represents the fourth known genus of oviraptorids found on nest, though the first unearthed with a preserved skull. The type of oviraptor is Nemegtomaia barsboldi which possessed a crested head, and was first described in 2004. Apparently it was excavated within 500 meters (1640') of where the first example had been found.

Two fossilized specimens were uncovered but the one that got the attention is the one that had originally been squatting amid a 89cm (35") wide and 101.5cm (40") long ring of eggs with its forelimbs splayed out to the sides in a classic brooding position when it apparently died suddenly, probably during a sandstorm or perhaps due to a dune-shifting event.

After Nemegtomaia's death bone borings, bone-chip-lined burrows, and reworked sediment indicate that much of its skeleton was significantly damaged by insects similar to dermestid beetles.

The joints of Nemegtomaia's left arm and leg were completely destroyed by insect damage, and nearly circular beetle bore holes ranging from 3 to 6mm (0.12 to 0.23")in diameter can be seen in the left side of the skull. Several ribs and the scapulae (shoulder blade) were also basically obliterated. They scavenged the dinosaur as it was only partially buried after death.

Preserved parts include much of the skull, the left forelimb and hand, legs, pubes, and distal portions of both feet.

Two layers of eggs were originally preserved below the body of the presumed mother (though there is some evidence it is a male who might have been supervizing or tending communal nests).

Large egg fragments from seven distinct eggs were found under the skull, left side of the neck, left humerus, left femur, and both feet in a lower layer where beetle damage was minor.

The remains of Nemegtomaia had previously been found in sediments laid down by a fluvial habitat while these were discovered in what had been arid/aeolian environment providing evidence that it may have been more adaptable than other oviraptorids from Mongolia and China whose remains are known exclusively from xeric or semi-arid environments.

Nemegtomaia1.jpg Nemegtomaia.png

Further Reading:

New Specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia Abstract & Paper

FOSSILIZED DINOSAUR MOM FOUND

And the Nemegt Mother Makes Four

When Beetles Ate Dinosaurs

[rogue06]

The oldest elephant tracks yet discovered have been found in the Al Gharbia region of Abu Dhabi, the capital and the second largest city of the United Arab Emirates, at a site designated Mleisa 1 and have been dated at around 7 myo (Late Miocene).

The site in the Arabian Desert covers an area of 12.3 acres which is roughly the size of nine U.S. football fields, seven soccer fields, or the base of the Great Pyramid of Giza. It was likely soft saline silt or mud at the time the tracks were made which has since turned into indurated light-grey marl (calcareous mudstone).

The tracks, believed to have been laid down by at least 13 individuals of different ages and sizes (determined by differing stride lengths and foot size) stretch up to 260 meters (853') long and are in several straight, parallel lines.

According to the researchers, led by Faysal Bibi, a vertebrate paleontologist from the University of Poitiers and the Museum of Natural History in Berlin, these tracks are the most extensive ever recorded for mammals and the 260 meter long one is the longest continuous fossil track ever found.

The prints are tightly spaced with very few intersections or overlaps, and small variations in direction. The researchers note that the fact that the herd's footprints never crossed one another strongly indicate that this was indeed a herd walking together, rather than individual animals crossing the same site at different times.

The individual prints are flat discs only up to 40cm (15¾") across. This makes them too small to photograph by satellite so the researchers used a remotely operated kite-mounted digital camera to take aerial photographs of the footprints.

They were probably laid down by the earliest known member of the elephant family, Stegotetrabelodon syrticus, which were larger than their modern relatives and were distinguished by sporting four tusks that projected from both the upper and lower jaws. It was the most abundant elephant ancestor in the area, and the most likely one to be found in open country.

These prints provide the earliest direct evidence of how the ancestors of modern elephants interacted socially, and are the oldest evidence known of an elephant herd. The herd was about the same size as elephant herds today and it appears that their tracks were crossed by a single large individual, probably a solitary male, traveling in a different direction at a slower and steadier speed than the herd.

The tracks laid down by the large individual demonstrates that these extinct early dinosaurs were divided into solitary and social groups -- just as today's modern elephants do.

At the time the Arabian Peninsula was wetter and supported a great deal more vegetation including large trees and was home to a great diversity of animals, including the afore-mentioned elephant ancestors along with hippopotamuses, giraffes, antelopes, pigs, monkeys, ostriches, turtles, crocodiles and fish along with a number of small and large carnivores.

elephanttrax.jpg
Stegotetrabelodon syrticus

elephanttrax1.jpg elephanttrax2.jpg

Further Reading:

Early evidence for complex social structure in Proboscidea from a late Miocene trackway site in the United Arab Emirates Abstract

Ancient tracks are elephant herd

Huge set of fossil tracks preserves march of the ancient elephants

Fossil footprints reveal oldest elephant herd

Ancient Elephants Followed the (Female) Leader

Proboscidian (Elephant Family): Stegotetrabelodon syrticus

[rogue06]

The oldest elephant tracks yet discovered have been found in the Al Gharbia region of Abu Dhabi, the capital and the second largest city of the United Arab Emirates, at a site designated Mleisa 1 and have been dated at around 7 myo (Late Miocene).

The site in the Arabian Desert covers an area of 12.3 acres which is roughly the size of nine U.S. football fields, seven soccer fields, or the base of the Great Pyramid of Giza. It was likely soft saline silt or mud at the time the tracks were made which has since turned into indurated light-grey marl (calcareous mudstone).

The tracks, believed to have been laid down by at least 13 individuals of different ages and sizes (determined by differing stride lengths and foot size) stretch up to 260 meters (853') long and are in several straight, parallel lines.

According to the researchers, led by Faysal Bibi, a vertebrate paleontologist from the University of Poitiers and the Museum of Natural History in Berlin, these tracks are the most extensive ever recorded for mammals and the 260 meter long one is the longest continuous fossil track ever found.

The prints are tightly spaced with very few intersections or overlaps, and small variations in direction. The researchers note that the fact that the herd's footprints never crossed one another strongly indicate that this was indeed a herd walking together, rather than individual animals crossing the same site at different times.

The individual prints are flat discs only up to 40cm (15¾") across. This makes them too small to photograph by satellite so the researchers used a remotely operated kite-mounted digital camera to take aerial photographs of the footprints.

They were probably laid down by the earliest known member of the elephant family, Stegotetrabelodon syrticus, which were larger than their modern relatives and were distinguished by sporting four tusks that projected from both the upper and lower jaws. It was the most abundant elephant ancestor in the area, and the most likely one to be found in open country.

These prints provide the earliest direct evidence of how the ancestors of modern elephants interacted socially, and are the oldest evidence known of an elephant herd. The herd was about the same size as elephant herds today and it appears that their tracks were crossed by a single large individual, probably a solitary male, traveling in a different direction at a slower and steadier speed than the herd.

The tracks laid down by the large individual demonstrates that these extinct early dinosaurs elephants were divided into solitary and social groups -- just as today's modern elephants do.

At the time the Arabian Peninsula was wetter and supported a great deal more vegetation including large trees and was home to a great diversity of animals, including the afore-mentioned elephant ancestors along with hippopotamuses, giraffes, antelopes, pigs, monkeys, ostriches, turtles, crocodiles and fish along with a number of small and large carnivores.

elephanttrax.jpg
Stegotetrabelodon syrticus

elephanttrax1.jpg elephanttrax2.jpg

Further Reading:

Early evidence for complex social structure in Proboscidea from a late Miocene trackway site in the United Arab Emirates Abstract

Ancient tracks are elephant herd

Huge set of fossil tracks preserves march of the ancient elephants

Fossil footprints reveal oldest elephant herd

Ancient Elephants Followed the (Female) Leader

Proboscidian (Elephant Family): Stegotetrabelodon syrticus

Slight correction

[rogue06]

Not a discovery of any sort, but rather a short tutorial from Smithsonian National Museum of Natural History’s dinosaur curator Matthew Carrano as he explains how paleontologists identify dinosaurs on the basis of teeth alone.

It helps to answer one of those Frequently Asked Questions about fossil identification

[rogue06]

Two new species of extinct penguin have been unearthed in the soft Kokoamu Greensand of New Zealand's Waitaki Region on the South Island. The three specimens date from 25-27 mya (Late Oligocene) and are represented by relatively complete skeletons and considered by the researchers to be among the most complete Paleogene penguins known.

The fossils were originally discovered during field exploration for fossil whales and dolphins starting in the 1970s but have only been properly examined now.

What makes them different is that their skeletons reveal a body shape that is different from any previously known penguin, living or extinct.

The two new species were named Kairuku waitaki and Kairuku grebneffi with the first or genus name loosely means "food diver" or "diver who returns with food" in the language of the native Maori's.

Kairuku waitaki gets very little mention in the press release and news reports. Kairuku grebneffi gets nearly exclusive attention or they're both quickly conflated into Kairuku, I guess, since I'm stuck doing not having had a chance to see the full paper.

Kairuku grebneffi, or hence forth Kairuku, had more slender body proportions than living penguins. The researchers have been calling it "svelte" and "elegant" in comparison to today's more blubbery penguins.

Aside from being overall slimmer with an elongate trunk, long, narrow beak or bill, and long, narrow wing bones (meaning long flippers), Kairuku's legs and feet, OTOH, were short and stout.

Further, it stood 1.3 meters (4'3") tall, making it the tallest penguin to have ever lived. As the head of the team, Daniel T. Ksepka, a North Carolina State University research assistant professor of marine, earth and atmospheric sciences, said, “If we had done a reconstruction by extrapolating from the length of its flippers, it would have stood over 6' tall."

Ksepka observed that still means that "they're bigger than anything that's alive today, they'd be head-and-shoulders above an Emperor Penguin." They would in fact be more than a foot taller than an Emperor Penguin who today reach 122cm (48") in height.

There were some other differences between Kairuku and modern penguins as well.

For example, its pygostyle (the fleshy protuberance seen at the rear end of a bird sometimes called a "Parson's Nose") lacks the derived triangular cross-section seen in modern penguins which suggests to the researchers that the rectrices (the stiff main feathers of a bird's tail that provide lift and maneuverability) attached in a more typical avian pattern and the tail may have lacked the propping function utilized by living penguins.

Still Kairuku's elongated flippers and beak, slender body and powerful legs meant they were probably good hunters. The researchers think that Kairuku also likely ate larger prey than today's penguins, including large fish and squid.

Kairuku was one of at least five different species of penguin that lived in New Zealand back in the same time during the Late Oligocene. The first Kairuku specimens were discovered in the 1940s by the noted New Zealand zoologist and paleontologist Dr. Brian J. Marples, but these bones weren't perceived as belonging to a new species at first because they were poorly preserved and typically included nothing more than a few pieces of a wing.

KairukuPenguin.jpg

Further Reading:

First Full Look at Prehistoric New Zealand Penguin has Abstract at end

New Fossil Penguin from New Zealand May be the Biggest Ever

Big Bird: Fossils of World's Tallest Penguin Discovered

Researchers Reconstruct Prehistoric Giant Penguin

Introducing Kairuku!

Large penguins 'used to inhabit NZ'

[rogue06]

Researchers have announced the discovery of nine fossilized fleas from two sites in China that extended the history of the parasites by at least 60 million years.

Five of the specimens had been excavated from 165 myo (Jurassic) ancient lake bottom that is part of the Daohugou beds in Ningcheng County, Inner Mongolia (northeast China). The other group of four came from a rocky outcrop in at Huangbanjigou in Liaoning Province, also in northeastern China, and is 40 million years younger at around 125 myo (Lower Cretaceous).

The features of these insects were preserved in such fine detail that it even lets the researchers identify claws on each it's six legs – and even the tiny teeth on these claws suggest that they were adapted to hang onto fur or feathers in that they would have allowed the fleas to cling to hair shafts and feathers. Fine spines on their bodies and legs were also visible.

While these fleas do resemble modern fleas in many respects there are several important and noticable differences.

The most obvious differences is that these ancient extinct fleas were a whole lot bigger than their modern descendants. Today's fleas range from 1mm up to a 12mm species which infests the mountain beaver of North America. In contrast, the largest females of these previously unknown Jurassic and Cretaceous species were 20.6mm (0.81") long, while males grew to 14.7mm (0.58"). Such sexual dimorphism with the females being twice the size of males is like what we see in today's fleas.

Further, these ancient Chinese fleas had yet to evolve their spring-legged, jumping specializations in their hind legs that allows them to leap long distances and which is characteristic of modern species. Instead, as noted above, their legs ended in long, curved claws.

Another recognizable difference between them and modern fleas is that their blood-sucking "siphonate" or strawlike mouth was both disproportionately long and sturdy, almost armored. This unusually long proboscis, was studded with sharp saw-like serrated edges, unlike the smooth jaws of modern fleas.

These over-sized flea mouthparts "had almost like a saw running down the side," observed one of the researchers, Michael Engel, a palaeoentomologist at the University of Kansas in Lawrence. "This thing was packing a weapon. They were equipped to dig into something."

“The mouthparts are certainly overkill for piercing the hides of early mammals and birds,” Engel added. “It really appears as though they were specialized for working their way into some heavy hides, such as those on dinosaurs.”

IOW, it helped them bite and feed from the hides of certain dinosaurs, probably those that had feathers considering the aforementioned claws at the ends of their legs. A considerable number of feathered dinosaurs have been found in China. And it probably should be noted that modern fleas feed exclusively on animals with fur and feathers.

The resemblence of these straw-like stabbing siphons to those of scorpionflies (a group of insects named after the males’ large genitals that look like a scorpion’s sting) provides a hint concerning the origin of fleas. Many scorpionflies have long proboscis that are used to probe the depths of flowers and suck up the nectar and pollen. It would appear that at some point in their history, some early scorpionflies adapted to feeding on a bloodier liquid.

So, looking at the long, serrated piercing tubes and grasping claws on these ancient gigantic fleas, it may be that they evolved from scorpionflies and first plagued feathered dinosaurs only later moving on to mammals and birds.

Giant_fleas1.jpg

Further Reading:

Diverse transitional giant fleas from the Mesozoic era of China Abstract

Super-sized fleas adapted to feed off dinosaurs

Scientists say giant fleas feasted on dinosaur blood

Fossils of giant fleas discovered

Giant Jurassic fleas sucked but couldn’t jump

Giant fleas plagued feathered dinosaurs

[rogue06]

A remarkably well preserved fossil specimen of a 75 myo (Late Cretaceous) sub-adult Velociraptor that was complete enough to allow for the preparation of its chest cavity as a single articulated piece was discovered back in 1994 in the Gobi Desert.

What makes this discovery remarkable is that part of what was probably its last meal was preserved inside the dinosaur’s body cavity. This is the first time that a Velociraptor's gut contents have been observed and what was found has intrigued the researchers.

They discovered the bone from a pterosaur, making this the first time a pterosaur bone has been found inside a theropod. The bone, which is 75mm (3") long, was lodged in the upper part of the Velociraptor's ribcage where the stomach would have been.

"The surface of the bone is smooth and in good condition, with no unusual traces of marks or deformation that could be attributed to digestive acids, noted the lead author David Hone of the School of Biology and Environmental Sciences at the University College Dublin in Ireland. "So it's likely that the Velociraptor itself died not long after ingesting the bone."

The Velociraptor itself had a broken rib indicating it was healing suggesting that the theropod was recovering from an injury at the time of death.

The researchers think that the Velociraptor probably didn't try taking on a healthy, full-sized pterosaur -- especially one bigger than it was. As Hone puts it, "It would be difficult and probably even dangerous for the small theropod dinosaur to target a pterosaur with a wingspan of 2 meters [6½'] or more, unless the pterosaur was already ill or injured."

The thin walls of the bone point to this pterosaur being an azhdarcid which were active hunters in their own right. A predator rarely tries to hunt another predator because they're too dangerous a prey, although a desperate, starving and injured animal I would think might take dangerous chances when survival is on the line.

If it had been predation then this was roughly equivalent to a small coyote taking down a large eagle. Extremely dangerous but nevertheless feasible. Still there is good reason to believe that the Velociraptor was scavenging rather than hunting prey.

If the pterosaur carcass was fresh, then the Velociraptor would have consumed the available soft tissues first. The fact that it consumed a large bone indicates to the researchers that the pterosaur had likely been picked over and there was only a little meat still on the remains when our Velociraptor came across it. Dinosaurs apparently slain by the smaller theropods tend to have the meat scraped from the bone rather than all of it being gobbling down.

This discovery demonstrates for the first time that small non-avian dinosaurs were capable of consuming relatively large bones, something seen in modern crocodiles. This bone would have been approximately the size of the Velociraptor's skull.

velociraptorpterosaur1.jpg

velociraptorpterosaur2.jpg
pterosaur bone in the dinosaur's gut (black arrows) with dinosaur's broken rib (white arrow)

Further Reading:

Fossils show dinosaur predators scavenged

Dinosaur Guts Reveal Velociraptor's Last Meal

What did Velociraptor have for dinner? Raptor skeleton discovered with bones in its gut

Lightweight dinosaur probably enjoyed a huge last meal

A Dinosaur’s Pterosaur Lunch

While the paper including even the abstract is behind a pay wall the lead author has posted extensively on the discovery on his blog "Archosaur Musings":

Velociraptor scavenging an azhdarchid pterosaur

More on dromaeosaurs vs azhdarchids

[rogue06]

Researchers working near the Panama Canal Zone has discovered two new species of long extinct camels from the Las Cascadas formation that lived approximately 20 myo (Early Miocene) and are considered to be among the oldest known animals from Panama.

The camelidae family arose in the early to middle Eocene in North America where they were widespread and this discovery marks the first time any members of it have been found south of Mexico.

The two camels were named Aguascalietia panamaensis and Aguascalientia minuta and are distinguished from one another primarily by size, which was tiny in comparison to modern camels.

The smaller of the two, Aguascalientia minuta, was only 60cm (23½") tall -- roughly the size of today's musk deer. Aguascalietia panamaensis stood around 80cm (31½") tall.

Both also had long, crocodile-like snouts, which along with the distinct tooth proportions demonstrate that these camels belong to an evolutionary branch of the camel family separate from the one that gave rise to modern camels

The leader of the study, Aldo F. Rincon, a graduate student in vertebrate paleontology at the University of Florida in Gainesville, spent two years piecing together tiny fragments into a nearly complete jaw. He thinks that they were probably specialized for finding fruits and leaves in dense vegetation of the Central American rain forests.

“They were probably browsers in the forests of the ancient tropics, Rincon said. "We can say that because the crowns are really short.”

croc-snout camel1.jpg crocsnoutcamel2.jpg

Further Reading:

New floridatragulines (Mammalia, Camelidae) from the early Miocene Las Cascadas Formation, Panama Abstract

"Cute" Tropical Camels: Prehistoric Species Found in Panama

CROCODILE-LIKE CAMEL FOUND

Two new species of extinct camels discovered in Panama Canal excavations

Two New Extinct Camel Species Discovered at Panama Canal Excavation

[rogue06]

Researchers have announced the discovery of the oldest animal with a skeleton in ancient sandstone beds in southern Australia that once lived on a shallow seafloor between 550 and 560 mya (Ediacaran period).

They have excavated hundreds of fossils of these thimble like organisms that consisted of a truncated cone that was around 15mm (0.6") tall by 22mm (0.86") wide with four 370mm (14½") long needlelike spicules radiating from its top of the cone. The researchers think this creature used the spicules as a skeleton to support its body in a similar manner as poles of a tent support it.

While early skeletons are often associated with predation, in that they are useful in helping animals fight off predators, this skeletal structure was only for support since there were apparently no predators back in the Ediacaran.

As one of the researchers, Mary L. Droser, a professor of geology at the University of California, Riverside notes, "Up until the Cambrian, it was understood that animals were soft bodied and had no hard parts. But we now have an organism with individual skeletal body parts that appears before the Cambrian."

Droser explains, "It is therefore the oldest animal with hard parts, and it has a number of them -- they would have been structural supports -- essentially holding it up. This is a major innovation for animals. It therefore provides a link between the two time intervals. We're calling it the 'harbinger of Cambrian constructional morphology,' which is to say it's a precursor of organisms seen in the Cambrian."

The researchers, led by Erica C. Clites of the Department of Earth Sciences, University of California at Riverside and a paleontologist at Glen Canyon National Recreation Area in Arizona, named this bizarre organism Coronacollina acula which means "little rimmed hill with needles" after the fossil's morphology, specifically the truncated cone-shaped body and the corona of long spicules.

It appears that Coronacollina was incapable of locomotion, meaning it most likely fed in the same manner as most sponges -- namely by filtering small particles of food from water that pass by or through some part of the organism.

But that isn't the only comparison to sponges that can be made. "Coronacollina not only compares well in shape to something identifiable -- a sponge -- but it specifically compares to the early Cambrian sponge Choia," Clites said. "More parallels between the Ediacaran and Cambrian may be identified by researchers in the future."

The Cambrian Choia is a low conical demosponge with a corona of long spicules and Clites team thinks that it provides a long-predicted constructional link between the Ediacara biota and the Cambrian fossil record.

Further, this discovery might also assist future researchers in identifying signs of life on alien worlds.

"Understanding the form early animals take on Earth may help scientists recognize structures on other planets that might otherwise go unnoticed," Clites explained. "Coronacollina outwardly appears like lines and pits in the rock, but we know that these textures represent a multi-element organism. Understanding the array of shapes of Earth's earliest animals provides a search image to be used during space exploration."

Coronacollina1.jpg

Coronacollina2.jpg Coronacollina3.jpg

Further Reading:

The advent of hard-part structural support among the Ediacara biota: Ediacaran harbinger of a Cambrian mode of body construction Abstract

Oldest Organism With Skeleton Discovered in Australia

Earth's Earliest Animal with a Skeleton Discovered

This strange sponge owned the world’s first known skeleton

[rogue06]

The colors of the feathers of yet another dinosaur have been identified, this time from the four-winged Microraptor which lived in what is present day northern China roughly 130 myo (Early Cretaceous).

In the past year or so it finally become possible to use scanning electron microscopes to examine well-preserved fossil remains of pigment containing cells called melanosomes that are so miniscule that a hundred can fit across a human hair.

What the researchers found was that Microraptor's feathers were probably a glossy black and had a metallic, iridescent sheen like that seen on today’s hummingbirds, peacocks, and swallows.

This is the oldest known example of iridescent color in feathers. Previously the earliest iridescent feathers were from 40 some myo birds and were found in the famous Middle Eocene Messel Oil Shale Pit near Darmstadt, Germany.

While the iridescence arises when the melanosomes are organized in stacked layers they can't be absolutely positive about the color of the sheen though since gaps between the melanosomes aren’t clear enough to measure and color is dependant upon the thickness of the feather's keratin coat which wasn't present.

As one of the researchers, Matthew D. Shawkey an assistant professor at the University of Akron's Department of Biology and Integrated Bioscience Program, said, "That keratin is not preserved in the fossil, so we couldn't directly infer a particular color of iridescence."

Still, if I'm reading things correctly, the shape of the melanosomes, which were especially narrow rather than the typical roundish or cigar-shaped, are similar to those found in feathers of birds with black plumage. One of the sources below even states that both black and iridescent (the majority) feathers were identified.

That there may be two types of feathers of different color is supported by the fact that bands of dark and light have been seen on some specimens.

While glossy, iridescent feathers can aid in flight and help regulate temperatures the researchers think they were predominantly used for mate-attracting displays. In other animals, especially birds, that shine is often how males attract attention to itself in order to find females to mate with.

As the paper describing the discovery notes, “although we cannot assign a definitive function to iridescence in Microraptors, a role in signaling aligns with data on the plumage.”

Or as one of the researchers involved, Mark Norell, chair of the American Museum of Natural History’s Division of Paleontology, noted, "we’ve determined that Microraptor, like many modern birds, most likely used its ornate feathering to give visual social signals."

His co-author Dr. Shawkey elaborates, “Iridescence is widespread in modern birds, and is frequently used in displays. Our evidence that Microraptor was largely iridescent thus suggests that feathers were important for display even relatively early in their evolution.”

Newer specimens of Microraptor which have been unearthed since the first one was described in 2003 reveal that this dinosaur had a striking pair of long, narrow tail feathers. While some had proposed that these elongated tail feathers assisted in flight it is now known that they weren't very aerodynamic and more likely hindered flight.

This means the tail feathers were probably there for decorative purposes. Microraptor likely flashed its tail feathers in the manner of a peacock.

It should be noted that if Microraptor did use its plumage to attract mates this contradicts previous interpretations that it was a nocturnal creature since it would be difficult to attract mates using black feathers in the dark. Further, dark glossy plumage is not a trait found in modern nighttime birds.

Finally, this new find demonstrates that iridescence isn’t an exclusive bird innovation being that it was around in their dinosaur predecessors as well. In fact, it appears that it is a relatively easy trait to evolve having independently turned up many times in bird evolution. Apparently it just takes subtle tweaks to the shape of the melanosomes and the way they are stacked to fashion shiny feathers from matte ones.

Microraptor2.jpg Microraptor1.jpg

Further Reading:

Reconstruction of Microraptor and the Evolution of Iridescent Plumage Abstract

Feathers Worth a 2nd Look Found on a Tiny Dinosaur

Tiny dinosaur sported shimmery black coat, decorative streamers, four wings

A shiny dinosaur –four-winged Microraptor gets colour and gloss

Birdlike dinos wore basic black with glossy touch

And a 3½ minute video:

[rogue06]

Right on the heels of evidence of a relatively small Velociraptor scavenging on a pterosaur comes a report of the discovery of a the fossilized remains of an ancient armored predatory fish called Aspidorhynchus in the act of swallowing the long-tailed pterosaur Rhamphorhychus headfirst -- right after the latter had caught and was itself swallowing a small leptolepidid fish!

The fossils were discovered in the Solnhofen Limestone, the famous Late Jurassic Konservat-Lagerstätte about halfway between Nuremberg and Munich in Bavaria in southern Germany, where Archaeopteryx and other fossils have been excavated.

The researchers think that the Aspidorhynchus grabbed the pterosaur's left wing from the front, as it was flying just above the water's surface after plucking up a small fish and had started swallowing it, and was dragged underwater and drowned.

Unfortunately for the Aspidorhynchus this encounter was fatal for it as well. Since their skulls make it difficult to manipulate prey that exceeded the standard gape of their jaws, it couldn't swallow the pterosaur due to its size and bulky skeleton.

What's more, beside not being able to swallow the pterosaur it seems that the Aspidorhynchus couldn’t get rid of it either.

The pterosaur’s left wing bones are distorted, while the rest of its skeleton is intact suggesting to the researchers that the fish had tried in vain to shake off its unwanted meal. Perhaps the tough fibers, the aktinofibrils, in the leathery membrane of Rhamphorhynchus’ wing snagged in Aspidorhynchus’ densely packed teeth.

At least three other instances of Rhamphorhynchus specimens tightly entangled with the rostrum of a large Aspidorhynchus were also discovered demonstrating that this wasn't something unheard of -- although this is the only one displaying evidence that the pterosaur was still alive when it was grabbed.

All of these pterosaurs had wingspans of approximately 70cm (27½") and were found with their wings either next to or in the mouths of the 65cm (25½") long fish which indicates that the latter tended to grab their prey by their wing membranes. In fact, in one of the slabs a wing bone of the Rhamphorhynchus is caught between the jaws of the fish.

Another distinct possibility for how the Aspidorhynchus died is that while they struggled they drifted or sank into the toxic anoxic water layer of the Late Jurassic Eichstätt basin where the fish rapidly suffocated.

In any case, with neither party able to break free, both died.

That the pterosaur was still alive is of course shown by the fact that its prey was still in its esophagus and that any type of later regurgitation of the leptolepidid fish tail first would be impossible because the still entact fins would have caught themselves in the wall of the narrow passage.

While today bats birds and bats are occasionally eaten by sharks and other large fish the researchers don't think that pterosaurs were regularly part of the diet for Aspidorhynchus but were instead probably lethal mistakes. Of all four slabs not a single one shows the pterosaur’s bones inside the fish’s stomach.

PterosaurFish1.jpg PterosaurFish2.jpg

Further Reading:

The Late Jurassic Pterosaur Rhamphorhynchus, a Frequent Victim of the Ganoid Fish Aspidorhynchus? Paper & Abstract

It's an ancient armored fish vs. a flying reptile

Jurassic fail: fish accidentally snags pterosaur, and both die

Looks like I picked the wrong week to quit writing about pterosaurs being killed…

[rogue06]

A nearly complete fossilized skull, mandible and the second to fifth cervical vertebrae of a previously unknown species and genus of pterosaur was discovered at Sihedang near Lingyuan City in the Liaoning Province from the Jiufotang Formation in northeast China that lived some 120 mya (Early Cretaceous).

The long and narrow skull is 38cm (15") and the researchers, headed by Xiaolin Wang of the Chinese Academy of Science in Beijing, figure that this extinct flying reptile had a wingspan between 395 to 485cm (13-16').

They named the pterosaur Guidraco venator with the first or genus name combining the Chinese "gui" meaning "malicious ghost" with the Latin word for dragon -- "draco." The species or second name is Latin for "hunter" so we have "ghost dragon hunter.”

Guidraco's head sported two rather distinctive features. The first being a remarkably helmet-like large crest on the top of its head which extended more or less straight up from the top of the head like a sail that probably stabilized flight.

The other was that it had a basket made up of large snaggled, but pointy teeth with the most forward ones projecting nearly directly forward at the end of its elongated face -- all of which is beautifully preserved.

Since all known pterosaurs consumed meat and a few coprolites (fossilized poop) were found with the skull and other remains that contained fish vertebrae, the researchers think that this arrangement assisted it in catching fish.

That they speared fish on their pointy teeth is unlikely in that they had no way to remove something impaled on one of them. More likely they used their teeth as a form of filter-feeding, randomly collecting material and using a long thin tongue to probe what it had for anything edible, knocking out everything that wasn't.

A phylogenetic analysis found that Guidraco represents a sister taxon of pterosaurs found in Brazil in 2003 called Ludodactylus sibbicki, which looks very similar but not identical with both having large teeth and a crest at the back of the skull.

And they may have even shared similar feeding strategies. The only known specimen of Ludodactylus indicates the pterosaur died by getting a plant leaf that it probably mistook for a fish wedged in its mouth while filter-feeding.

The new find contributes further evidence that at least 40 species of pterosaurs were more globally distributed than previously thought as well as suggesting that at least some early Cretaceous pterosaur clades, such as the Tapejaridae and the Anhangueridae, might have originated in Asia.

Guidraco venator1.jpg
With a smile only a mother could have loved.
The objects marked "copr" are the coprolites

Guidraco venator2.jpg

Further Reading:

New toothed flying reptile from Asia: close similarities between early Cretaceous pterosaur faunas from China and Brazil Abstract

120-Million-Year-Old ‘Ghost Dragon’ Pterosaur Discovered in China

Year of the ghost dragon – Guidraco

Guidraco venator

[rogue06]

Yet another interesting fossil of a creature with the remains of other creatures inside it has been reported. This time it's within the compressed coiled shell of an ammonoid that was found in the Posidonia Shale at Dotternhausen, near Balingen in southwestern Germany that is approximately 180 myo (Early Jurassic).

Ammonites were a group of marine invertebrate animals that went extinct at the end of the Cretaceous and are more closely related to modern squid and octopuses than to shelled cephalods like the Nautilus. The specimen here was from the species Harpoceras falciferum and is 23cm (9") in diameter.

The aptychi, or hard plate from the shell itself is long gone as is the shell itself, but the periostracum, or the outermost layer of the shell, remains and is translucent (as well as a golden brown in color) enabling researchers to observe the contents inside the ammonite.

What they found was three tiny lobsters no more than 25mm (1") long located within the body chamber in the outermost whorl though still more than halfway inside the coiled shell.

While not all the details are clearly visible, the overall outline and details indicate that the lobster specimens belong to the extinct family of the Eryonidae -- a group that lived from the Late Triassic to the Early Cretaceous which had compressed, circular bodies with spikes around the rim. Any further identification is impossible for now.

The problem for the researchers, headed by Adiël A. Klompmaker, a paleontologist with Kent State University's Department of Geology, to solve was how did these lobsters enter the ammonoid shell.

The researchers considered several explanations for the fossil juxtaposition including whether the lobsters had been eaten; they had washed into into the body chamber by bottom currents; or whether they were merely molts and not the remains of the lobsters themself.

The eliminated the possibility that they had been eaten by the ammonite because the three lobsters appear to be complete or nearly so. The researchers think that this makes a crop/stomach content interpretation impossible since the lobsters would have been chewed up and reduced to pieces and preserved in the location of the ammonoid’s digestive tract.

And the completeness of the lobsters along with the presence of more than one individual essentially in the same position within the ammonoite, and their radial tail to tail preservation (they form a semicircle facing away from each other, with their tails basically centered around the same spot) all appear to exclude the possibility of transportation into the body chamber by bottom currents.

Finally, the remains of the lobsters appear to represent actual corpses rather than just molted shells based (again) on the completeness of the specimens in general (molted shells should display the characteristic split down the midline for one thing), their preservation in dorsal position and the radial positioning of the lobsters in relation to each other with their tails close together within the ammonite's body chamber.

All these things strongly indicates that these lobsters were alive when entombed but just why the lobsters congregated inside the shell remains a mystery.

They likely used the shell as some sort of shelter in preparation for molting or as protection against predatory fish. OTOH, it might be that the lobsters scavenged the ammonite's soft tissue as a source of food and were attracted by that. Or perhaps the shell was serving as a long-term residency where they could store food they had collected.

Maybe it was a combination of factors. For the time being there’s just no way to tell which of these possibilities is correct.

Interestingly every specimen of this species of lobster found at this site has been associated with an ammonoid shell. This suggests that these lobsters might have specialized in making homes out of empty shells.

In any case the researchers said that this discovery represents the earliest evidence of gregarious behaviour in decapods (the group which lobsters belong to).

ammonoid-lobsters1.jpg ammonoid-lobsters2.jpg

Further Reading:

Animal Behavior Frozen in Time: Gregarious Behavior of Early Jurassic Lobsters within an Ammonoid Body Chamber Abstract & Paper

Prehistoric Lobsters Made Homes of Ancient Ammonoid Shells

[rogue06]

Two new species and genus of Leptoceratopsid neoceratopsians (horned dinosaurs) have been identified based on fossils collected in Alberta, Canada years ago and stored in museums. Both lived during the Late Cretaceous and were much smaller than their larger Triceratops and Torosaurus relatives.

The first was found in the Black Coulee locality (formerly Deadhorse Coulee), near the Writing-on-Stone Provincial Park, from the Dinosaur Park Formation and is roughly 75 myo.

The researchers named it Unescoceratops koppelhusae with the first or genus name honoring the fact that Dinosaur Provincial Park is designated a UNESCO World Heritage Site along with the Greek word "ceratops," meaning "horned face." The species is named for Eva Koppelhus, a palynologist at the University of Alberta and wife of Philip Currie who discovered the section of the left mandible (lower jaw) in 1995.

They estimate that Unescoceratops was somewhere between 1-2 meters (3.2 to 6.5') long and probably weighed under 91 kg (200 lbs.). It sported a short frill extending from behind its head but lacked ornamentation on its skull and possessed a parrot-like beak. Its teeth were lower and rounder than those of any other leptoceratopsid and its hatchet-shaped jaw had a distinct portion of bone that jutted out below the jaw like a small chin

Unescoceratops was originally referred to as Leptoceratops before this new examination and a cladistic analysis found it to be among the most advanced leptoceratopsid genera

The other specimen represents both the oldest and smallest horned dinosaur found so far in North America and was excavated from bonebed 55 of the Milk River Formation in the northwest corner of Dinosaur Provincial Park in southern Alberta in 1950. It is estimated to have lived 83 mya.

The right side of a mandible was pieced together from fragments that were, as it was described, "pulled out a little box that's no bigger than a coffee cup."

It was named Gryphoceratops morrisoni with the first part derived from the name of a mythological Greek creature called a "Gryphon" that had the body of a lion and the head of an eagle (referring to the dinosaur's beaked face) again along with "ceratops." The species name honors Ian Morrison, a Royal Ontario Museum technician who discovered how the bones fit together.

Gryphoceratops possessed a shorter and deeper jaw shape than any other leptoceratopsid which the researchers think came from a full-sized adult. Based on the size of the jaw it appears that adults measured 0.5 meters (1.6') in length

So not only was Gryphoceratops the smallest adult-sized horned dinosaur in North America it also represents one of the smallest plant-eating dinosaurs known.

Further, while also now the oldest known leptoceratopsid, like Unescoceratops a cladistic analysis found Gryphoceratops to be one of the most advanced leptoceratopsids.

It would seem that with their small sizes, these dinosaurs would have made for tasty snacks for larger predators.

One of the researchers, David C. Evans, associate curator of vertebrate palaeontology at the Royal Ontario Museum and assistant professor at the University of Toronto, said, "Small-bodied dinosaurs are typically poorly represented in the fossil record, which is why fragmentary remains like these new leptoceratopsids can make a big contribution to our understanding of dinosaur ecology and evolution."

The importance of these two tiny dinosaurs is made clear by the leader of the team, Michael J. Ryan, curator of vertebrate paleontology at The Cleveland Museum of Natural History in Ohio: "These dinosaurs fill important gaps in the evolutionary history of small-bodied horned dinosaurs that lack the large horns and frills of relatives like Triceratops from North America."

"Although horned dinosaurs originated in Asia, our analysis suggests that leptoceratopsids radiated to North America and diversified here, since the new species, Gryphoceratops, is the earliest record of the group on this continent."

UnescoceratopsJaw.jpg
Unescoceratops

GryphoceratopsJaw.jpg
Gryphoceratops

Gryph-&-Unesco.jpg
Unescoceratops on top Gryphoceratops below

Further Reading:

New leptoceratopsids from the Upper Cretaceous of Alberta, Canada Abstract

Scientists Name Two New Species of Horned Dinosaur includes 4¾ min video

New Horned Dinosaurs Found—Among Littlest Known

Two new dinosaur species fill in evolutionary gaps‎

Miniature 'Triceratops' Ancestor Discovered

Two New Species of Horned Dinosaurs Identified

[Der Kanzler]

Right on the heels of evidence of a relatively small Velociraptor scavenging on a pterosaur comes a report of the discovery of a the fossilized remains of an ancient armored predatory fish called Aspidorhynchus in the act of swallowing the long-tailed pterosaur Rhamphorhychus headfirst -- right after the latter had caught and was itself swallowing a small leptolepidid fish!

This is literally the coolest thing I have ever seen.