Snowsalamander

In the annals of paleontology, Snowmastodon holds a very special place. The site isn’t only remarkable for what was discovered there – a dense Ice Age boneyard containing at least 35 mastodons, four mammoths, and numerous other fossils – but the fact that paleontologists and volunteers carefully excavated and documented the fossils in less than nine months. It’s a great example of uncovering prehistory under pressure, and those hectic excavations of 2010-2011 are already starting to bear scientific fruit.

Thanks to a list of interdisciplinary researchers too long to name individually (just have a look at the author lists!), the journal Quaternary Research has devoted an entire issue to the Snowmastodon site. This is just the first rush of papers, but they set the foundation for understanding what the high-altitude habitat was like between 140,000 and 77,000 years ago.

Despite falling within the “Ice Age”, for example, the earliest sediments from the site actually document a relatively warm, wet habitat where American mastodon and Jefferson’s giant ground sloths browsed among conifer forests that bordered a broad lake. In time, the climate became cooler and drier. The forests began to die back and the lake was filled in to form a marshy meadow closer to 77,000 years ago, and this is when “Snowy” the mammoth and deer moved in.

But even though Snowmastodon was named for a classic and charismatic megamammal the American mastodon wasn’t the most numerous vertebrate at the site. Not even close.

Snowmastodon at the time of the mastodons (top) and mammoths (bottom). Tiger salamanders thrived through these changes. From Miller et al., 2014.
Snowmastodon at the time of the mastodons (top) and mammoths (bottom). Tiger salamanders thrived through these changes. From Miller et al., 2014.

After sorting through all the recovered remains, the Snowmastodon researchers documented a minimum number of 35 mastodons and over 1,800 individual mastodon bones in sediments from 140,000 to 110,000 years old. Compare that to the haul of tiger salamanders. Their bones were typically too small to see out in the field, but, in doing preparation on the big bones and sifting sediment, the Snowmastodon team has documented over 22,000 bones from tiger salamanders that represent at least 500 individuals which lived during the entire 140,000 to 77,000 year range.

I get marketing and I like puns. The site was rich with mastodons and uncovered near Colorado’s Snowmass Village, so Snowmastodon was the obvious choice for a popular name. But if sheer numbers were to dictate the name, Snowsalamander would be the clear winner.

Of course, tiger salamanders are not nearly as exciting as big shaggy mammals that disappeared practically yesterday. It’s a hard break for the herps. Then again, they are among the species preserved at Snowmastodon that survived to the present.

The tiger salamanders of Ice Age Colorado were the same species as those alive today. They thrived at the site’s lake and marshland, and bones from every stage of their development show that the salamanders lived at Snowmastodon for generation after generation. One tiger salamander skeleton was even found inside a mastodon’s tusk, buried as it sheltered inside the modified incisor. This makes the tiger salamander yet another connection to the not-too-distant past, and every time I see one I can’t help but think of the little amphibian clambering over the fresh, submerged bones of a mastodon in those Ice Age days.

To learn more about Snowmastodon, read the new Quaternary Research issue devoted to the bonebed.

References:

Fisher, D., Cherney, M., Newton, C., Rountrey, A., Calamari, Z., Stucky, R., Lucking, C., Petrie, L. 2014. Taxonomic overview and tusk growth analyses of Ziegler Reservoir proboscideans. Quaternary Research. 82: 518-532. doi: 10.1016/j.yqres.2014.07.010

Miller, I., Pigati, J., Anderson, R., Johnson, K., Mahan, S., Ager, T., Baker, R., Blaauw, M., Bright, J., Brown, P., Bryant, B., Calamari, Z., Carrara, P., Cherney, M., Demboski, J., Elias, S., Fisher, D., Gray, H., Haskett, D., Honke, J., Jackson, S., Jimenez-Morena, G., Kline, D., Leonard, E., Lifton, N., Lucking, C., McDonald, H., Miller, D., Muhs, D., Nash, S., Newton, C., Paces, J., Petrie, L., Plummer, M., Porinchu, D., Rountrey, A., Scott, E. Sertich, J., Sharpe, S., Skipp, G., Strickland, L., Stucky, R., Thompson, R. Wilson, J. 2014. Summary of the Snowmastodon Special Volume: A high-elevant, multi-proxy biotic and environmental record of MIS 6-4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA. Quaternary Research. 82: 618-634. doi: 10.1016/j.yqres.2014.07.004

Sertich, J., Stucky, R., McDonald, H., Newton, C., Fisher, D., Scott, E., Demboski, J., Lucking, C., McHorse, B., Davis, E. 2014. High-elevation late Pleistocene (MIS 6-5) vertebrate faunas from the Ziegler Reservoir fossil site, Snowmass Village, Colorado. Quaternary Research. 82: 504-517. doi: 10.1016/j.yqres/2014.08.002

Leave a Reply

Your email address will not be published. Required fields are marked *