Electroblemma bifid: A Bizarre ARMORED Spider in Amber From Cenomanian Cretaceous Myanmar

A bizarre armoured spider (Araneae: Tetrablemmidae) from Upper Cretaceous Myanmar amber

Authors:

Selden et al

Abstract:

A new genus and species of tetrablemmid spider, Electroblemma bifida n. gen. et sp., is described, from two adult males found in Upper Cretaceous (Cenomanian) amber of Myanmar. The genus is distinguished by its enormous dorsal carapace projection and highly modified chelicerae. The new genus is referred to the tribe Tetrablemmini within the subfamily Tetrablemminae. The presence of a relatively derived tetrablemmid on the south-east Eurasian continent during the Late Cretaceous suggests that the family was already well diversified in tropical rainforests at this time.

a 3d Video Reconstruction of a 410 million Year old Pragian/Lochkovian Devonian Arachnid

Researchers from The University of Manchester and the Museum für Naturkunde, Berlin, used exceptionally preserved fossils from the Natural History Museum in London to create the video showing the most likely walking gait of the animal; the study is published in a special issue of the Journal of Paleontology today (Wednesday).

The scientists used the fossils - thin slices of rock showing the animal's cross-section - to work out the range of motion in the limbs of this ancient, extinct early relative of the spiders. From this, and comparisons to living arachnids, the researchers used an open source computer graphic program called Blender to create the video showing the animals walking.

"When it comes to early life on land, long before our ancestors came out of the sea, these early arachnids were top dog of the food chain," said author Dr Russell Garwood, a palaeontologist in the University of Manchester's School of Earth, Atmospheric and Environmental Sciences. "They are now extinct, but from about 300 to 400 million years ago, seem to have been more widespread than spiders. Now we can use the tools of computer graphics to better understand and recreate how they might have moved – all from thin slivers of rock, showing the joints in their legs."

Co-author Jason Dunlop, a curator at the Museum für Naturkunde, Berlin, said: "These fossils – from a rock called the Rhynie chert – are unusually well-preserved. During my PhD I could build up a pretty good idea of their appearance in life. This new study has gone further and shows us how they probably walked. For me, what's really exciting here is that scientists themselves can make these animations now, without needing the technical wizardry – and immense costs – of a Jurassic Park-style film.

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Scorpion is Gondwana's Oldest Known Land Animal

A postdoctoral fellow from Wits University has discovered the oldest known land-living animal from Gondwana in a remote part of the Eastern Cape. Dr Robert Gess, from the Evolutionary Studies Institute at Wits, discovered the 350 million year old fossilised scorpion from rocks of the Devonian Witteberg Group near Grahamstown. This unique specimen, which is a new species, has been called Gondwanascorpio emzantsiensis.

His discovery has been published in the peer reviewed journal African Invertebrate on Wednesday, 28 August 2013.

Explaining his discovery, Gess said that early life was confined to the sea and the process of terrestrialisation - the movement of life onto land - began during the Silurian Period roughly 420 million years ago. The first wave of life to move out from water onto land consisted of plants, which gradually increased in size and complexity throughout the Devonian Period.

This initial colonisation of land was closely followed by plant and debris-eating invertebrate animals such as primitive insects and millipedes. By the end of the Silurian period about 416 million years ago, predatory invertebrates such as scorpions and spiders were feeding on the earlier colonists of land.

By the Carboniferous period (350 million years ago), early vertebrates - our four-legged ancestors -had in turn left the water and were feeding on the invertebrates. Although we knew that Laurasia -the single northern landmass then comprising what is today North America and Asia - was inhabited by diverse invertebrates by the Late Silurian and during the Devonian, this supercontinent was at the time separated from the southerly positioned Gondwana by a deep ocean.

"Evidence on the earliest colonisation of land animals has up till now come only from the northern hemisphere continent of Laurasia, and there has been no evidence that Gondwana was inhabited by land living invertebrate animals at that time," explained Gess.

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Cretaceous Spider Attack Caught in Amber

The extraordinarily rare fossils are in a piece of amber that preserved this event in remarkable detail, an action that took place in the Hukawng Valley of Myanmar in the Early Cretaceous between 97-110 million years ago, almost certainly with dinosaurs wandering nearby.

Aside from showing the first and only fossil evidence of a spider attacking prey in its web, the piece of amber also contains the body of a male spider in the same web. This provides the oldest evidence of social behavior in spiders, which still exists in some species but is fairly rare. Most spiders have solitary, often cannibalistic lives, and males will not hesitate to attack immature species in the same web.

"This juvenile spider was going to make a meal out of a tiny parasitic wasp, but never quite got to it," said George Poinar, Jr., a professor emeritus of zoology at Oregon State University and world expert on insects trapped in amber. He outlined the findings in a new publication in the journal Historical Biology.

"This was a male wasp that suddenly found itself trapped in a spider web," Poinar said. "This was the wasp's worst nightmare, and it never ended. The wasp was watching the spider just as it was about to be attacked, when tree resin flowed over and captured both of them."

Spiders are ancient invertebrates that researchers believe date back some 200 million years, but the oldest fossil evidence ever found of a spider web is only about 130 million years old. An actual attack such as this between a spider and its prey caught in the web has never before been documented as a fossil, the researchers said.

Earliest Spider Web in Amber

The tiny tangled threads of the world's oldest spider web have been found encased in a prehistoric piece of amber, a British scientist said Monday.

Oxford University paleobiologist Martin Brasier said the 140-million-year-old webbing provides evidence that arachnids had been ensnaring their prey in silky nets since the dinosaur age. He also said the strands were linked to each other in the roughly circular pattern familiar to gardeners the world over.

"You can match the details of the spider's web with the spider's web in my garden," Brasier said.

The web was found in a small piece of amber picked up by an amateur fossil-hunter scouring the beaches on England's south coast about two years ago, Brasier said. A microscope revealed the existence of tiny threads about 1 millimeter (1/20th of an inch) long amid bits of burnt sap and fossilized vegetable matter.

While not as dramatic as a fully preserved net of spider silk, the minuscule strands show that spiders had been spinning circle-shaped webs well into prehistory, according to Simon Braddy, a University of Bristol paleobiologist uninvolved with the find.

"It's not a striking, perfect web," Braddy said. "(But) this seems to confirm that spiders were building orb webs back in the early Cretaceous" — the geological term for the period of time between 145.5 and 65.5 million years ago when dinosaurs and small mammals shared the earth.

140 MYA puts it on the Valanginian-Berriasian boundary more or less.