A new fossil spider

New fossil finds seem to come out of China on a weekly basis, fostered by international collaborations between Chinese and western scientists. Most famous among the Chinese discoveries are the feathered dinosaurs and rare early mammals, but there are also significant finds of humble invertebrates.

Incredibly well preserved spiders (click on the photo for an enlarged view for details) were discovered in Mongolia from rocks 120 million years old. Even though the fossil spiders are barely 5 mm long, their exceptional preservation permits paleoarachnologists to identify them as members of a modern family of spiders that previous has only been known from the USA, Mexico, Cuba, and Costa Rica.

The discovery extends the geologic range of the family 120 million years to the Middle Jurassic, and indicates that these spiders were much more widely distributed in the past.

Photo and source: Paul Selden and Diying Huang, 2010, The oldest haplogyne spider (Araneae: Plectreuridae), from the Middle Jurassic of China. Naturwissenschaften 97:

See also: Paul Selden and David Penny, 2010. Fossil Spiders. Biological Reviews 85:171-206

S'moa DNA

Scientists from Down Under have extracted DNA from feathers of the extinct moa, the 2.5 meter tall birds that dominated New Zealand’s terrestrial ecosystems until the arrival of humans and non-native mammals about 700 years ago.

Previously, DNA had been extracted from the feathers of modern birds and from museum specimens of birds that have gone extinct in historical time, and only from the base or quill end of the feathers.

The moa study showed that viable DNA could be obtained from older, subfossil feathers and from the distal end of the feather, the rachis and barbs. Scientists are not seeking to use the DNA to clone the moa, but to identify the species of moa that they come from.

The success with moa feathers demonstrates that useful information can be obtained from subfossil feathers and from parts of feathers not previously considered useful in genetic analysis.

Reference: Nicolas J. Rawlence, Jamie R. Wood, Kyle N. Armstrong, and Alan Cooper, 2009, DNA content and distribution in ancient feathers and potential to reconstruct the plumage of extinct avian taxa. Proceedings of the Royal Society, B, October 7, 2009 276:3395-3402; published online before print July 1, 2009, doi:10.1098/rspb.2009.0755

Photo credit: Extinct Monsters by Rev. H. N. Hutchinson, illustrations by Joseph Smit (1836-1929) and others. 4th ed., 1896. Plate XXIII between pages 232 and 233.

Oldest DNA

Fossil DNA hunting is a recent phenomenon, as it was long assumed that the molecules could not survive the vagaries of time and preservation to become fossils.

The current claim for oldest preserved DNA comes from 419-million-year-old salt deposits from Canada. This is an amazing claim, as previous “oldest DNA” reports are from animals only tens of thousand years old.

Every claim of old DNA is subject to intense scrutiny and is accepted only after successful independent trials to replicate the results. The 419 million year old DNA is from salt-loving or halophilic bacteria, representatives of which are still around today and which provide a comparison for the fossil DNA sequences.

The discovery of halophiles gives encouragement to looking for microbes in other unusual places...like Mars. Click on today's title to learn more.

Reference: J.S. Park, et al.,, 2009, Geobiology 7 no. 5, p. 515-523, Haloarchaeal diversity in 23, 121 and 419 MYA salts

Ancient accidental pollinators

Back in the days before plants developed flowers to attract insects to help disperse their pollen, wind was the main agent of pollenation.

However, paleontologists recently argued that some pre-flowering plants had pollen receptors located deep within the plant so that wind-borne pollen would be unlikely to reach them. These scientists suggest that a little-known group of fossil insects called scorpionflies might have served in pollinating these pre-flowering plants.

These fossil scorpionflies (descendants of which are still around today) have narrow, elongate mouthparts suited for reaching far into plants and feeding on fluids, so it is unlikely they could have ingested the large pollen grains. Instead, pollen grains may have stuck to the insect’s head or mouthparts as they fed, and scorpionflies became accidental pollinators—the first known pollinators of pre-flowering plants.

Reference: Ren, D., Labandeira, C., Santiago-Blay, J., Rasnitsyn, A., Shih, C., Bashkuev, A., Logan, M., Hotton, C., & Dilcher, D. (2009). A Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies Science, 326 (5954), 840-847 DOI: 10.1126/science.1178338)

Photo credit: http://z.about.com/d/animals/1/0/n/g/18149_web.jpg

Serendipity with a backhoe

This is a story of what happens when construction workers have some appreciation for interesting rocks and fossils they come across in the course of their daily tasks:

While excavating oil sands in a mine near the town of Ft. McMurray, Alberta, Canada, a heavy machinery operator uncovered the skeleton of a plesiosaur, the extinct, long-necked reptile that inhabited Mesozoic seas.

The skeleton had been fragmented by its excavation by backhoe rather than small hammers, chisels and brushes, but when pieced back together, it was judged to be 80% complete.

The find is significant because it is the earliest North American occurrence of a plesiosaur, extending the known geologic range of these animals to the early part of the Cretaceous Period and this find also expands the known geographic range of plesiosaurs in North America.

Reference: Journal of Paleontology November, 2009, Earliest North American occurrence of a plesiosaur

Photo credit: http://www.dinosaurjungle.com/focus_plesiosaur.jpg. For more on plesiosaurs, go to this site or click on today's title.

Fossil "Mother Lodes"

The history of life on Earth is a story told in photographs made of stone--the rocks and fossils preserved when and where conditions were favorable. Some of these photos are time exposures in which events blur together, others, much rarer, are snapshots of an instant in time. These snapshots commonly are the result of the sudden, rapid burial of the organisms living in the environment, as through an ocean storm surge or river flood or avalanche or entrapment in a mucky bog or sticky pit of natural asphalt. These snapshots are characterized by exquisite preservation of anatomical details not usually fossilized, and fossil deposits of this sort are referred to by a German word, lagerstatte, which is a mining term that refers to a "mother lode" or abundance of ore. Fossil lagerstatte are "mother lodes" of exceptionally preserved fossils. The Pennsylvanian (320-286 million year old) Mazon Creek fauna, from which the bizarre Tullymonstrum (the state fossil of Illinois, seen here from the side of a U-Haul truck) is known is one example.

This week's GeoLog challenge is to describe the 5 most significant fossil faunas or lagerstaette, fossil "mother lodes." Despite the relative rarity of exceptional preservation, the list of lagerstaette, for example the list posted on the Wikipedia website, takes up a whole page, so some selection criteria need to be imposed. My "top 5" lagerstaette were chosen to include different geological periods, different depositional or geological environments, and a variety of organisms, from microfossils to dinosaurs, and for their historical significance.

Paleontologically, all lagerstaette are important, because we've learned things from each of them about the variety and diversity of life that we would not have known otherwise.