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Age. Late Wisconsin. Dates on sloth dung (11,140 ± 200, Y-1163B) and hide (9,840 ± 160, Y-1163A) were reported by Simons and Alexander (1964). Y-1163A was thought to be affected by preservatives (Long and Martin 1974), accounting for the date later than that of Y-1163B. Holocene material also has been recovered (see below).
General Description. Lull (1929) described the fumarole from information supplied by Chester R. Longwell of Yale, who visited the site in August of 1928. The east side of Aden Crater has a narrow opening that seems to form a natural entrance into the crater itself. However, the opening into the fumarole lies across this pathway, forming a pitfall trap. The opening has a maximum diameter of 8 feet. The pit, nearly vertical in its upper portions, is over 100 feet deep.
Discussion. The Shasta Ground Sloth (Nothrotheriops shastensis), for which this site is famous, apparently was recovered from the fumarole in 1927 or 1928, with Yale receiving a letter and photos from Ewing Waterhouse of El Paso on 25 February 1928.
Fig. 1. Google Earth view of the Aden Fumarole and Khulo sites. The irregular, darker formations that make up most of the view are the Afton and Aden lava flows. North is to the top.
The sloth was found in a chamber about 100 vertical feet below the entrance, "almost completely buried in the dry, loose guano" (Lull 1929:3). On the other hand, skeletons of coyotes and a bobcat were on the surface of the guano and were presumed to be recent. Thus the non-sloth material probably is Holocene, at least in part. Several El Pasoans retrieved further material, most likely Holocene, in the last half of the 20th Century; this material is curated in the UTEP collections.
Fig. 2. Opening of the Aden Crater Fumarole. Photograph courtesy of Angela Chávez.
Eames (1930) reported on the makeup of a coprolite associated with the sloth.
Buteo—Hawk (Probably Holocene)
†Nothrotheriops shastensis—Shasta Ground Sloth
Lepus—Jackrabbit (Probably Holocene)
Lynx rufus—Bobcat (Probably Holocene)
Canis latrans—Coyote (Probably Holocene)
Ursus americanus—Black Bear (Pleistocene or Holocene)
Odocoileus hemionus—Mule Deer (Probably Holocene)
Last Update: 18 Mar 2010