Revista Chilena de Historia Natural 83 (4): 557-566, 2010
RESEARCH ARTICLE
Differentiation of Xenarthra (Mammalia) species through the identification of their fecal bile acid
patterns: An ecological tool
The analysis of feces is a fundamental tool for field work, especially to identify the
presence of certain species in an area. Fecal bile acids and their relative concentration follow patterns that are species-specific, and
can be characterized by Thin Layer Chromatography (TLC). This technique has been used for differentiating feces of several mammal
species; however it has never been used for Xenarthra species. In this work, 96 feces of Xenarthra species were analyzed by TLC to
determine the bile acid pattern. The species were: Zaedyus pichiy (n = 10), Chaetophractus vellerosus (n =
5), Chaetophractus villosus (n = 57), Dasypus hybridus (n = 4), Priodontes maximus (n =
2), Tamandua tetradactyla (n = 14) and Myrmecophaga tridactyla (n = 4). There were differences
between the bile acid patterns of all the species, but not between males and females, nor between wild and captive animals of the
same species. We found seven known bile acids, cholesterol and seven unidentified compounds (X<sub>1</sub>-
X<sub>7</sub>). All the species had taurocholic, glycochenodeoxycholic and lithocholic acids, and cholesterol. Only C.
villosus had deoxycholic acid (R<sub>f</sub>: 0.30 ± 0.01). Z. pichiy, C. vellerosus
and C. villosus had two or three bands of dehydrocholic acid (R<sub>f</sub> between 0.29 ± 0.06 and
0.45 ± 0.02), while the other species had one or two. Z. pichiy had two unidentified bile acids, X<sub>6</sub>
(R<sub>f</sub>: 0.85 ± 0.06) and X<sub>7</sub> (R<sub>f</sub>: 0.93 ± 0.03), that were almost
indistinguishable in other species. D. hybridus differed from Z. pichiy, C. vellerosus and C.
villosus because it did not have chenodeoxycholic acid and X<sub>2</sub>. T. tetradactyla was the only
species without cholic acid and it differed from M. tridactyla because it had dehydrocholic acid. D. hybridus
was the species with the lowest number of compounds (seven), and differed from the others because it did not have the
X<sub>1</sub> and X<sub>5</sub> unidentified compounds. These results are the first for Xenarthra and would be
very important for future studies about the conservation and the ecophysiology of the group.
Key words:
conservation, fecal bile
acids, TLC, Xenarthra
