Elk bones tell stories of life, death, and habitat use at Yellowstone National Park
Dec10

Elk bones tell stories of life, death, and habitat use at Yellowstone National Park

Josh Miller is one among a small cadre of ecologists looking at living ecosystems through the relics of their dead. by Liza Lester, ESA communications officer Flags mark bone locations as field assistant Jared Singer maps a carcass near a lake in Yellowstone National Park. Credit, Joshua Miller. ________________ JOSH Miller likes to call himself a conservation paleobiologist. It’s a label that makes sense when he explains how he uses bones as up-to-last-season information on living animal populations. “At parties I used to say, well—I’m a paleontologist; I study modern ecosystems,” Miller said. That sounded counterintuitive, so he needed a new designation, hence the conservation angle. “There are quite a few of us taking up that mantle, people passionately looking at bones—mostly in marine environments. People have done a lot with shells.” Bones, he says, are evidence of which animals lived where, and in what relative numbers. They provide baseline ecological data on range animals complementary to aerial counts, adding an historical component to live observation. In his November research report in Ecology, he assesses the habitat use of elk in Yellowstone National Park by their bones and antlers, testing his method against several decades of the Park Service’s meticulous observations. Miller came to ecology via paleontology. Now an assistant research professor in the new Quaternary and Anthropocene Research Group in the Department of Geology at the University of Cincinnati, he located and recorded the elk bone data while a doctoral student in evolutionary biology at the University of Chicago and finished analyzing the data during a brief stint at the Florida Museum of Natural History at the University of Florida, in Gainesville. His work with modern animals started as an inquiry into the fidelity of bone remains to the living ecosystems of the past. He wanted to know how faithfully the fossil record archived historical populations, variability, and change—if digging up 72 Triceratops and 44 Tyrannosaurus conjured up something real about the relative numbers of the dinosaurs when they were alive, and the ecosystem  they lived in so many millions of years ago. “Do those data mean anything, or is it just some random, biased grab bag?” he wondered. He started looking at modern, living species that could help answer the question by experiment, going out with a team of helpers among the bison, elk, and deer on the vast rolling grasslands and forests of Yellowstone’s northern range for three summers, to catalog the remains of elk of years past, They zig-zagged down huge, kilometer long sample plots looking for bones, antlers, scat—anything with a bone in it. “It turns out that bones are really informative,” he said....

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Giant turtles all the way down
Nov08

Giant turtles all the way down

A Colombian coal mine opens a treasure chest of fossils. By Liza Lester IT was large, that much was obvious. When Edwin Cadena first saw the fossil in 2005, he thought he might be uncovering another specimen of Titanoboa cerrejonensis, the ancient snake he and his colleagues discovered in 2004 on a Smithsonian expedition lead by Carlos Jaramillo, Jason Head, and Jonathan Bloch. But as he slowly picked the rock away, the fossil was revealed as another giant reptile, a ~58-million-year-old contemporary of Titanoboa, and one of the largest freshwater turtles ever found. So big, even the 13-meter, two ton snake probably couldn’t swallow it. He named it Carbonemys cofrinii, “coal turtle.” Cadena, now a doctoral student with Dan Ksepka at NC State, found his turtle in the La Puente cut in the north zone of Colombia’s Cerrejón mine, one of the largest open-pit coal mines in the world. La Puente is an expanse of naked mudstone, stripped of jungle and a layer of coal. Hot, windy, and full of bones, with distant methane fires blooming off and on from an active face, it looks apocalyptic in photos. It is a treasure chest of fossils. View Larger Map We have few fossils from the tropics, where ancient remains lie deep buried under living jungle and tons of soil. It is rare that natural erosion reveals the secrets of the ancient tropics. The coal mine has peeled back the surface for the paleontologists, gratis. Candena has an awareness of his a time-table. Fossil excavation is slow work. He has only a few years to finish projects in progress before active mining resumes. How did the snakes and turtles get so large? Cadena thinks habitat and ecological interactions drove the gigantism. In addition to giant reptiles, the mine has uncovered the ancient jungle they in lived in, a wealth of plant fossils as important to understanding ancient ecosystems as the exciting megafauna. The fossil plant world is surprisingly familiar. The team has seen precursors of the living jungle, including modern bean, banana, and chocolate plants. Climate change may also have been a factor. Based on the great size of Titanoboa, Head et al concluded that the mean annual temperature of equatorial South America must have been warmer, in the range of 30–34 °C, consistent with controversial hot Palaeogene climate models. It seems the Colombia of the Palaeocene neotropics was not that unlike today, only more so – hotter, wetter, bigger. Cadena, E., Ksepka, D., Jaramillo, C., & Bloch, J. (2012). New pelomedusoid turtles from the late Palaeocene Cerrejón Formation of Colombia and their implications for phylogeny and body size evolution Journal of...

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