11 May 2016
What About the Nose
Macrauchenia has a long flexible rostrum. The skeleton of the animal does not possess any fossilized structures that show this, however the evidence for the attachment of soft tissues corresponding to an elongated rostrum are visible on the cranium. the hypothesis that the marks indicated a trunk-like proboscis is comparable to that of saiga antelopes, which helped to develop the hypothesis and probably facilitated its general acceptance. The idea behind nostrils like that is unlike the reasons for elephant trunks and is related much more to keeping dust out of the respiratory tract of the animals. When an animal that probably avoided predators by running and kicking lives in a dusty environment it stands to reason it will have many adaptations to keeping foreign dust particles from clogging its lungs and stomach. These reasons make the saiga antelope parallelism make more sense. The diet of Macrauchenia also lends some credence to the likelihood of dust filtration rather than feeding being the primary reason for the appendage. The diet of Macrauchenia consisted of leaves and other small amounts of vegetation. However, some scientists think that the teeth of the animal were not suited to grasping leaves and assert that the trunk was therefore used for that purpose rather than primarily for filtering dust from the air.