Greg McDonald is here  cataloging Megalonyx bones from the site.  He found  a right fifth metacarpal of a Paramylodon harlani that we had misidentified as a Megalonyx metatarsal.  This is the first confirmed record of a Paramylodon in Iowa.  

The bone was found by the landowner, Bob Athen, in 2006 on a gravel bar about 200 feet downstream from where we are currently digging. We assumed it had been transported there by the 1993 flood that exposed the original deposit.  That may still be true.  The bone is in excellent condition and retains all of its muscle scars, etc.  It did not roll far.  An analysis of the rare earth elements in the bone may tell us if the animal died about the same time as our sloth family.

Harlan’s ground sloth was the second largest of North America’s four Ice Age ground sloth species, weighing in at approximately 3,070 lbs.–about  20% more than Jefferson’s sloth (McDonald, 2005).  P. harlani was a grazer, or perhaps more properly a browser-grazer (Naples, 1989) and widespread on North America’s grasslands.  M. jeffersonii is believed to have been a browser. . . . Dave

References

McDonald, H.G. 2005.  Paleoecology of extinct Xenarthrans and the Great American Biotic Interchange.  Bulletin of the Florida Museum of Natural History 45: 313-333.

Naples, V.L. 1989.  The feeding mechanism in the Pleistocene ground sloth, Glossotherium.  Contributions in Science, Natural History Museum of Los Angeles County 415: 1-23.

Sloth Advisors, Volunteers and Friends,

Let’s start with the good news. The NSF has awarded the sloth project $20,000 to continue excavation, conduct a detailed osteological analysis of the remains, start exploratory DNA analysis of the adult and two juveniles and provide for an outreach intern to maintain the sloth website and  design teaching materials focused on the sloth analysis. NSF regards this award as preparatory for submittal of another proposal for comprehensive analyses of the sloths including a series of chemical analyses on the bone as well as detailed studies of associated seeds, pollen and depositional environments at the time the sloths died. We are pleased to continue our association with NSF.

The bad news is water. As you know the Shenandoah area has been declared a disaster area. I hesitate to hazard another guess about when we will be able to dig again. Bob tells me that water in the Tarkio was up to his picnic table, our staging and overlook area, last week. That’s 30 feet above the sloth. It has dropped to 8 feet but the current is too fast to construct new levees (we will use an excavator for this). It may be late summer or early fall before things dry up as predicted. The NSF grant runs for two years so we have time. Also, NSF tells me that a 6 month extension is easy to get. That gives us through summer 2010 to recover the critters. Hopefully, the sloth-bearing unit, which is resistant to erosion, has not been materially damaged.  Holmes

It’s bad for sloth-digging but worse for farmers.  http://www.valleynewstoday.com/site/news.cfm?newsid=19760409&BRD=2703&PAG=461&dept_id=555139&rfi=6  

Dave

From the picnic area on top of the south bank. 

The water is high but not nearly as high as we expected after all the rain the area has received.  Holmes thinks we may be able to go out and dig in July.   He’ll talk to Bob this weekend and send an update to our sloth rapid response team next week. Watch for more here soon.

  Looking upstream, North.

                                                                      South bank looking downstream.