Laelaps

A moment frozen in time - fossil fish trace solves paleontological puzzle

Thu, 06 May 2010 15:13:01 -0500

One of the fossil fish I found in the Green River Formation of Wyoming.

I had my doubts about whether we were going to reach the quarry. The Toyota Yaris my wife and I had rented for our excursion through Utah and Wyoming was not designed to handle the rough dirt roads which wound their way through the grassy hills of the Equality State, but eventually the outcrop of grey-and-yellow rocks came into view. It was part of the famous Green River Formation, an approximately 42-53 million year old slice of earth's history known to be rich in fish fossils.

It did not take long to start finding what we were after. Almost immediately after we started splitting the shale left over in the quarry's spoil pile we began to find the rust-colored skeletons of small fish which had long ago settled to the bottom of an Eocene lake (though, to be honest, that afternoon's activities yielded far more fossil fish feces than fish). These quarries are so chock-full of these fossils, in fact, that fish quarried from them can be found at just about every gas station store in the area, yet despite the familiarity people have with this formation it still holds many secrets. In 2008, for example, scientists announced the discovery of a new fossil bat Onychonycteris finneyi from the Green River Formation, and a paper published this week in the journal PLoS One reports on another exceptional find from this formation.

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Eavesdropping lions zero-in on African wild dog calls

Wed, 05 May 2010 19:22:24 -0500

African wild dogs (Lycaon pictus), photographed at the Bronx Zoo.

African wild dogs (Lycaon pictus) don't have it easy. Their taste for large mammalian prey puts them in competition with lions and spotted hyenas for both prey and living space, meaning that wild dogs regularly have their kills stolen or are even killed by other predators. In fact, the dogs may even be unintentionally attracting the attention of these other hunters.

Like other social carnivores, African wild dogs communicate with each other through body language and olfactory cues, but they also employ a variety of high-pitched vocalizations. Despite their social benefits, however, the chirps and twitterings of these canids also come with costs. Eavesdroppers can use the information gained through what they overhear to their own advantage, and this can be especially dangerous in the case of lions. They kill wild dogs if they can catch them, and by vocalizing wild dogs run the risk of calling attention to their dens, their kills, or even themselves.

That lions do hone in on African wild dog calls is supported by a recent paper by scientists Hugh Webster, John McNutt, and Karen McComb published in the journal Ethology. Over the course of several years the team ran a series of playback experiments in Botswana's Okavango Delta in which African wild dog calls ("twitters") were played in the vicinity of lions and spotted hyenas (as well as bird calls similar to the wild dog vocalizations as a control and spotted hyena whoops to see if there was a difference in reactions). In all the researchers observed the reactions of 51 lions from a minimum of six prides and 11 spotted hyenas from three clans, with one month between each experiment.

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Photo of the Day #914: Sumatran tiger

Wed, 05 May 2010 16:19:34 -0500

Rokan the Sumatran tiger (Panthera tigris sumatrae), photographed at the National Zoo in Washington, DC.
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Where are all the males? - ancient DNA raises questions about extinct moa populations

Tue, 04 May 2010 11:53:52 -0500

The skeletons of female (larger, background) and male (smaller, foreground) Dinornis robustus, with a pigeon skeleton for comparison. From Allentoft et al 2010.

A little more than 700 years ago, multiple species of the gigantic, flightless birds called moas were still running around New Zealand. They ranged over almost the entirety of the North and South Islands, from the coast to the mountain forests, but when the Maori people arrived in the late 13th century the birds were quickly driven to extinction. Within a few hundred years they were entirely wiped out (along with the immense Haast's eagle, which fed on the moas), but fortunately for scientists these birds left behind vast accumulations of bones.

Two such moa graveyards are the Pyramid Valley and Bell Hill Vineyard sites on South Island. Together they record the presence of four moa species (Dinornis robustus, Emeus crassus, Euryapteryx curtus, Pachyornis elephantopus) over the course of the 3,000 years prior to the arrival of the Maori, and these sites presented scientists with the opportunity to recover ancient DNA from a large sample of bones to investigate the population genetics of the birds, including the sex of each individual. As they collected and analyzed the genetic data, however, they found something they were not expecting. In each species and across both deposits, females, which are considerably larger and heavier than males, were significantly more common, with an average of five females for every one male out of a sample of 227. What could could account for this disparity?

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NCSE Classic

Mon, 03 May 2010 18:05:00 -0500

Way back in 1989 (I was only six!), Eugenie Scott and other members of the National Center for Science Education got together for a mock debate pitting evolutionary scientists against creationist impersonators at the annual meeting of the American Association of Physical Anthropologists. How things have changed (well, except young earth creationist arguments)...

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The horse-hunting hyenas of Srbsko Chlum-Komin Cave

Mon, 03 May 2010 15:05:06 -0500

Breaking down a hyena kill. Given competition with other carnivores, prehistoric hyenas (like their living counterparts) would probably have disarticulated and transported parts of horses they killed. From Diedrich 2010.

In Hollywood films, there is nothing like an assemblage of bones strewn about a cave floor to testify to the power and voraciousness of a predator. Every skeleton is a testament to the hunting prowess of the carnivore, which causes even more alarm when the person who has stumbled into the cave realizes that they have just walked into a literal dead-end.

Although amplified for dramatic effect in the movies, this cinematic convention is based upon fact. Some mammalian carnivores do create bone assemblages in caves, and through the fossil record we know that they have been doing so for millions of years. In fact, the bone-collecting habits of carnivores have proven to be a boon for paleontologists, creating assemblages which not only represent the animals which lived in the area, but also provide clues as to the interactions between predator and prey during the distant past.

One such monument is Srbsko Chlum-Komin Cave in the Czech Republic. Discovered in 1942, this Upper Pleistocene site was once a spotted hyena den, and the activities of these predators caused many of the over 3,500 large mammal bones to become preserved at the site. Over 350 elements from hyena skeletons, bone-filled coprolites (fossil feces), and tooth-marked bones identify the cave as a place where the prehistoric hyenas took parts of their prey in order to consume them in relative peace, but, as explained by paleontologist Cajus Diedrich in Quaternary International, this assemblage is not quite like the other fossil hyena dens found elsewhere in Europe.

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Photo of the Day #913: Keel-billed toucan

Sun, 02 May 2010 09:39:15 -0500

A keel-billed toucan (Ramphastos sulfuratus), photographed at the Central Park, Zoo.
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Photo of the Day #912: Deer skull

Sat, 01 May 2010 08:39:52 -0500

The skull of a juvenile white-tailed deer (Odocoileus virginianus), photographed in suburban Pennsylvania.
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Friday Rewind: The rise and fall of Alabamornis

Fri, 30 Apr 2010 18:03:48 -0500

I feel like I have been run over by a truck. Between blogging, working on my book, fieldwork, pitching freelance articles, and research, I just didn't have the energy to come up with something new today. Instead enjoy this post, written a little more than a year ago, about how the hip of a fossil whale was mistaken for the shoulders of an ancient bird. -- Brian

The right hip of Basilosaurus as seen in Lucas' 1900 description.

If you were a 19th century paleontologist and you wanted a skeleton of the fossil whale Basilosaurus, there was only one place to look; Alabama. Even though fossils of the ancient cetacean had been found elsewhere, their bones were most abundant in this state, and naturalists such as S.B. Buckley, Albert Koch, and Richard Harlan based their descriptions of Basilosaurus on specimens from the Yellowhammer State. Unfortunately, however, most of the skeletons were fragmentary. Vertebrae were common, but parts of the rest of the skeleton were extremely rare.

Then, in 1896, the paleontologist Charles Schuchert made a discovery that was altogether unexpected. Associated with a chain of Basilosaurus vertebrae were a pair of what appeared to be hips, and these bones were described by Frederic Lucas in 1900. It was difficult to tell whether they had been attached to the spine or suspended in the flesh of the body as in living cetaceans, which do have vestiges of a pelvis and sometimes limbs in their bodies, but this was the first recorded discovery of Basilosaurus hips. (It would later be found that Basilosaurus still had small external hind limbs but the hips were fully detached from the spine.)

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Photo of the Day #911: Pronghorn

Fri, 30 Apr 2010 17:40:46 -0500

A male pronghorn (Antilocapra americana), resting in the tall grass. Photographed on Antelope Island, Utah.

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Newly-discovered bones answer questions about fossil primate locomotion

Thu, 29 Apr 2010 15:41:51 -0500

Utah may seem like an odd place to search for primates, but you can find them if you know where to look. Although scrubby and arid today, between 46-42 million years ago what is now the northeastern part of the state was a lush forest which was home to a variety of peculiar fossil primates. Called omomyids, these relatives of living tarsiers are primarily known from teeth and associated bits and pieces of bone, but newly discovered postcranial remains may provide paleontologists with a better idea of how some of these ancient primates moved.

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Photo of the Day #910: Bison

Wed, 28 Apr 2010 21:19:00 -0500

A bison (Bison bison), photographed on Antelope Island, Utah.
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Does the New Jersey State Museum have a future?

Wed, 28 Apr 2010 08:38:07 -0500

UPDATE: Due to ongoing deliberations over the future of the New Jersey State Museum I have decided that it is in the best interest of the museum to remove this post, but I will continue to write about this story as more knowledge becomes publicly available. And, just so there is no misunderstanding, what I stated in the previous version of this post I wrote as a private citizen and not a representative of the museum itself - I am the equivalent of a volunteer and not employed by the museum.

Nevertheless, I feel it appropriate the outline what is publicly known about this controversy in the place of my earlier editorial. As of July 1 the museum will be placed under the care of Rutgers University - it is presently unknown what the intentions of the school are for the museum. Since no funding for the museum was set aside in the state budget for the next fiscal year and Rutgers has had its funding repeatedly slashed by the state over the past several years, this could place the fate of the museum and its unique collections in jeopardy should Rutgers decide it does not want the institution (as well as the state library and Thomas Edison State College, which it is also being given by the state government).

If you care about the future of the museum and the research being actively pursued there, I urge you to voice your support for it through e-mails to New Jersey governor Chris Christie and Rutgers University president Richard McCormick.

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In defense of paleontology

Tue, 27 Apr 2010 09:16:36 -0500

Fossil fish from the Eocene age Green River Formation in Colorado. From Wikipedia.

I am pretty tired of Richard Dawkins putting down paleontology. In his 2004 tome The Ancestor's Tale, as well as in his latest book The Greatest Show on Earth, Dawkins felt compelled to cast the fossil record as an unnecessary bonus when it comes to demonstrating the reality of evolution. "The evidence for evolution would be entirely secure," he asserts in the latter book, "even if not a single corpse had ever fossilized." While this statement contains a crumb of truth - we have learned much about evolution by studying living organisms - I cannot help but feel it snobbishly denigrates an entire field which has greatly influenced our understanding of evolution. This trend is hardly new.

In his 1919 appraisal of evolutionary science, A Critique of the Theory of Evolution, the embryologist Thomas Hunt Morgan damned paleontology with faint praise. No discipline more immediately demonstrated the truth of evolution than paleontology, Morgan wrote, but when paleontologists made any attempt to move beyond simply describing fossils they had a bad habit of concocting hare-brained evolutionary schemes:

My good friend the paleontologist is in greater danger than he realizes, when he leaves descriptions and attempts explanation. He has no way to check up his speculations and it is notorious that the human mind without control has a bad habit of wandering.

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Photo of the Day #909: Nyala

Mon, 26 Apr 2010 17:59:48 -0500

An nyala (Tragelaphus angasii), photographed at the Bronx Zoo.
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