I'm just a Paleobiology major trying to share the beauty of the past, praise silt, and all of its wonders yet to be uncovered.

 

Hello, friends!

I have returned briefly to alert you that I shan’t be returning for some time. Being a student is hard, and will only get harder. I don’t have time for tumblr right now or any time soon. I’m sorry.

Gosh it’s been a while, hasn’t it?

I don’t think I’ve even been on Tumblr since November…

Who wants to learn about the “monsters” of our past?

rhamphotheca:

Giganotosaurus is a genus of carcharodontosaurid dinosaur that lived around 95 million years ago during the early Cenomanian stage of the Late Cretaceous Period. It included some of the largest known terrestrial carnivores, slightly larger than the largest Tyrannosaurus. Its fossils have been found in Argentina. fossils belonging to Andesaurus and Limaysaurus have been recovered near the remains of Giganotosaurus, leading to speculation that these carnivores may have preyed on the giant herbivores

(read more: Wikipedia)       (images: T - Dmitry Bogdanov; B - Matt Martyniuk)

rhamphotheca:

Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation (2007)
by Simmons, Seymour, Habersetzer & Gunnell
Synopsis
Bats (Chiroptera) represent one of the largest and most diverse radiations of mammals, accounting for one-fifth of extant species. Although recent studies unambiguously support bat monophyly and consensus is rapidly emerging about evolutionary relationships among extant lineages the fossil record of bats extends over 50 million years, and early evolution of the group remains poorly understood.
Here we describe a new bat from the Early Eocene Green River Formation of Wyoming, USA, with features that are more primitive than seen in any previously known bat. The evolutionary pathways that led to flapping flight and echolocation in bats have been in dispute, and until now fossils have been of limited use in documenting transitions involved in this marked change in lifestyle. Phylogenetically informed comparisons of the new taxon with other bats and non-flying mammals reveal that critical morphological and functional changes evolved incrementally.
Forelimb anatomy indicates that the new bat was capable of powered flight like other Eocene bats, but ear morphology suggests that it lacked their echolocation abilities, supporting a ‘flight first’ hypothesis for chiropteran evolution. The shape of the wings suggests that an undulating gliding–fluttering flight style may be primitive for bats, and the presence of a long calcar indicates that a broad tail membrane evolved early in Chiroptera, probably functioning as an additional airfoil rather than as a prey-capture device. Limb proportions and retention of claws on all digits indicate that the new bat may have been an agile climber that employed quadrupedal locomotion and under-branch hanging behaviour.
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from Nature 451, 818-821 (14 February 2008) | doi:10.1038/nature06549; Received 21 September 2007; Accepted 10 December 2007
http://www.nature.com/nature/journal/v451/n7180/full/nature06549.html
(via: NovaTaxa)

rhamphotheca:

Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation (2007)

by Simmons, Seymour, Habersetzer & Gunnell

Synopsis

Bats (Chiroptera) represent one of the largest and most diverse radiations of mammals, accounting for one-fifth of extant species. Although recent studies unambiguously support bat monophyly and consensus is rapidly emerging about evolutionary relationships among extant lineages the fossil record of bats extends over 50 million years, and early evolution of the group remains poorly understood.

Here we describe a new bat from the Early Eocene Green River Formation of Wyoming, USA, with features that are more primitive than seen in any previously known bat. The evolutionary pathways that led to flapping flight and echolocation in bats have been in dispute, and until now fossils have been of limited use in documenting transitions involved in this marked change in lifestyle. Phylogenetically informed comparisons of the new taxon with other bats and non-flying mammals reveal that critical morphological and functional changes evolved incrementally.

Forelimb anatomy indicates that the new bat was capable of powered flight like other Eocene bats, but ear morphology suggests that it lacked their echolocation abilities, supporting a ‘flight first’ hypothesis for chiropteran evolution. The shape of the wings suggests that an undulating gliding–fluttering flight style may be primitive for bats, and the presence of a long calcar indicates that a broad tail membrane evolved early in Chiroptera, probably functioning as an additional airfoil rather than as a prey-capture device. Limb proportions and retention of claws on all digits indicate that the new bat may have been an agile climber that employed quadrupedal locomotion and under-branch hanging behaviour.

__________________________________________________

from Nature 451, 818-821 (14 February 2008) | doi:10.1038/nature06549; Received 21 September 2007; Accepted 10 December 2007

http://www.nature.com/nature/journal/v451/n7180/full/nature06549.html

(via: NovaTaxa)

rhamphotheca:

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Looking for the evolutionary origins of our pretty smile

by PhysOrg

It takes both teeth and jaws to make a pretty smile, but the evolutionary origins of these parts of our anatomy have only just been discovered, thanks to a particle accelerator and a long dead fish. 

All living jawed vertebrates (animals with backbones, such as humans) have teeth, but it has long been thought that the first jawed vertebrates lacked pearly gnashers, instead capturing prey with gruesome scissor-like jaw-bones. However new research, led by the University of Bristol and published today in Nature, shows that these earliest jawed vertebrates possessed teeth too indicating that teeth evolved along with, or soon after, the evolution of jaws.

Palaeontologists from Bristol, the Natural History Museum and Curtin University, Australia collaborated with physicists from Switzerland to study the jaws of a primitive jawed fish called Compagopiscis. 

The international team studied fossils of Compagopiscis using high energy X-rays at the Swiss Light Source at the Paul Scherrer Institut in Switzerland, revealing the structure and development of teeth and bones. Lead author, Martin Ruecklin of the University of Bristol said: “We were able to visualise every tissue, cell and growth line within the bony jaws, allowing us to study the development of the jaws and teeth…

(read more: PhysOrg)             

(images: Sculptured reconstruction of the placoderm Dunkleosteus - Credit: Esben Horn; CT-scan courtesy of Phil Anderson, University of Massachusetts Amherst; Michael Ryan and Eric Snively, Cleveland Museum of Natural History; model and images Martin Rücklin, University of Bristol)

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More information: ‘Development of teeth and jaws in the earliest jawed vertebrates’ by Rücklin, M., Donoghue, P. C. J., Johanson, Z., Trinajstic, K., Marone, F. and Stampanoni, M., Nature, 2012.

Journal reference: Nature

Provided by University of Bristol

Hi guys! I think I’ll have some free time this weekend to write a post or two, but in the meantime, enjoy stuff from rhamphotheca here, he’s a pretty cool guy. I suggest you follow him if you like nature and animals and what have you. 

rhamphotheca:

Missing Links and Found Links:  Enter the Fishapod

In and out of the water, transitional forms from the fossil record illuminate the nuts and bolts of evolution

by Pat Shipman

I am equally enamored of another found link, the fossil skeleton of Tiktaalik roseae, described on April 6, 2006, in the journal NatureTiktaalikis a name suggested by the elders of the Nunavut people, who live where the fossils were found on Ellesmere Island in the Canadian Arctic; it means “large, shallow-water fish.” This 375-million-year-old fish shows a delicious combination of unexpected features, some inherited from its fishy ancestors and some typical of later land-dwelling tetrapods (four-footed animals). Neil Shubin of the University of Chicago, co-leader of the discovery team, jokingly calls the newly discovered species a “fishapod.”

Tiktaalik’s fins, gills, scales and primitive jaw show it was a fish. Unlike fish and like tetrapods, it had a distinct neck, so its head moved independently of its body. Its flattened head and broad body make Tiktaalik look somewhat like a weird, scaly crocodile, an impression enhanced by its four-to-nine-foot length. Its skeleton differs markedly from those of crocodiles or alligators, though, despite the overall resemblance in body shape. Tiktaalik’s front fins hold the biggest surprise. Each was a sort of half-fin, half-leg containing the bony elements found in a limb—with a functional wrist, elbow and shoulder—and yet retaining the bony “rays” of a fish fin. According to team member Farish Jenkins, Jr., of Harvard University, the front fins were sturdy enough to support the creature in very shallow water or on land for brief trips…

(read more: American Scientist)

(images: T - Ted Daeschler/VIREO; B - Kalliopi Monoyios)

http://youtu.be/B9h1tR42QYA

rhamphotheca:

Prehistoric Spider Ancestor Had Big Brain 
by Sid Perkins
Have spiders gotten dumber over time? That’s one possible conclusion from 50 well-preserved fossils excavated from 520-million-year-old rocks in southwestern China.
The fossils belong to a 6-centimeter-long early arthropod—a group that includes insects; spiders; scorpions; and crustaceans such as shrimp, crabs, and lobsters—which had a surprisingly modern brain. Several specimens of the species, Fuxianhuia protensa (left), contain dark areas within their eye stalks (see fossil, above right; gray areas in sketch, bottom right) that represent preserved clusters of neural tissue, including clumps along the optic nerve (labeled 1 through 3 in the sketch) and the brain (lowermost mass). The eye stalks were preserved in many different positions—a sign that they were flexible and that the creatures could control their movement, the researchers report online today in Nature.
Furthermore, they say, the appearance of such a complex brain early in arthropod evolution suggests that the nervous systems of modern-day arthropods with simpler brains—such as spiders, scorpions, and the crustaceans known as water fleas—were at some point downsized by evolution, a contrast with previous notions that the brains of arthropods in those lineages had remained simple since arthropods first arose.
(via: Science NOW)               
(images: X. Ma et al., Nature 490 (11-Oct) ©Macmillan Publishers Ltd )

rhamphotheca:

Prehistoric Spider Ancestor Had Big Brain

by Sid Perkins

Have spiders gotten dumber over time? That’s one possible conclusion from 50 well-preserved fossils excavated from 520-million-year-old rocks in southwestern China.

The fossils belong to a 6-centimeter-long early arthropod—a group that includes insects; spiders; scorpions; and crustaceans such as shrimp, crabs, and lobsters—which had a surprisingly modern brain. Several specimens of the species, Fuxianhuia protensa (left), contain dark areas within their eye stalks (see fossil, above right; gray areas in sketch, bottom right) that represent preserved clusters of neural tissue, including clumps along the optic nerve (labeled 1 through 3 in the sketch) and the brain (lowermost mass). The eye stalks were preserved in many different positions—a sign that they were flexible and that the creatures could control their movement, the researchers report online today in Nature.

Furthermore, they say, the appearance of such a complex brain early in arthropod evolution suggests that the nervous systems of modern-day arthropods with simpler brains—such as spiders, scorpions, and the crustaceans known as water fleas—were at some point downsized by evolution, a contrast with previous notions that the brains of arthropods in those lineages had remained simple since arthropods first arose.

(via: Science NOW)               

(images: X. Ma et al., Nature 490 (11-Oct) ©Macmillan Publishers Ltd )

rhamphotheca:

When Fanged Dwarf Dinosaurs Roamed the Earth
by Gisela Telis
Some dinosaurs were weirder than others. Long before Stegosaurus and Triceratops stomped the earth, heterodontosaurs scampered about the supercontinent Pangaea armed with porcupinelike bristles and sharp, protruding fangs. The housecat-sized family has been the source of debate for decades.
Because heterodontosaurs’ prominent canines resembled those of carnivores, some paleontologists have argued that the creatures supplemented their plant-based diets with insects or small animals. Others have claimed that the vampire fangs were mostly for show, used to spar with rivals for mates or to scare away predators. Now Pegomastax africanus may settle the question. This 2-foot-tall genus of heterodontosaur—which was unearthed in the 1960s but languished in a museum drawer until now—has a parrotlike skull and the genus’s distinctive fangs.
But microscopic analysis of the wear marks on its teeth and a reconstructed flesh model of its close cousin, Heterodontosaurus, suggest it used its mighty choppers to nip and spar, and not for wholesale meat-eating, researchers report online today in ZooKeys. By filling in more of the heterodontosaur family tree, the rediscovered Pegomastax could shed light on the family’s origins, and why they declined and disappeared long before dinosaurs as a whole went extinct.
(via: Science NOW)          (Photo, Video, and Sculpting by Tyler Keillor)

rhamphotheca:

When Fanged Dwarf Dinosaurs Roamed the Earth

by Gisela Telis

Some dinosaurs were weirder than others. Long before Stegosaurus and Triceratops stomped the earth, heterodontosaurs scampered about the supercontinent Pangaea armed with porcupinelike bristles and sharp, protruding fangs. The housecat-sized family has been the source of debate for decades.

Because heterodontosaurs’ prominent canines resembled those of carnivores, some paleontologists have argued that the creatures supplemented their plant-based diets with insects or small animals. Others have claimed that the vampire fangs were mostly for show, used to spar with rivals for mates or to scare away predators. Now Pegomastax africanus may settle the question. This 2-foot-tall genus of heterodontosaur—which was unearthed in the 1960s but languished in a museum drawer until now—has a parrotlike skull and the genus’s distinctive fangs.

But microscopic analysis of the wear marks on its teeth and a reconstructed flesh model of its close cousin, Heterodontosaurus, suggest it used its mighty choppers to nip and spar, and not for wholesale meat-eating, researchers report online today in ZooKeys. By filling in more of the heterodontosaur family tree, the rediscovered Pegomastax could shed light on the family’s origins, and why they declined and disappeared long before dinosaurs as a whole went extinct.

(via: Science NOW)          (Photo, Video, and Sculpting by Tyler Keillor)

To the responses to my dumbfounded-ness of mineralogy: Yes, dumbfounded in a bad way. It just doesn’t slot into my brain the right way, it’s a reverse squiggly where I need a “T” block.

In other news, I’ll be posting again soon. Yay. Content.