Ultra diffuse galaxies are a population of extended galaxies but with relatively low luminosities .
The origin of these objects remains unclear , largely due to the observational challenges of the low surface brightness Universe .
We present here a detailed stellar population analysis of a relatively-isolated UDG , DGSAT I , based on spectroscopic data from the Keck Cosmic Web Imager integral field unit .
The star formation history of DGSAT I seems to be extended , with a mean luminosity-weighted age of \sim 3 Gyr , in agreement with previous photometric studies .
However , we find a very high [ Mg/Fe ] abundance ratio , which is extreme even in the context of the highly alpha-enhanced massive ellipticals and ultra-faint dwarfs .
The [ Mg/Fe ] -enhancement of DGSAT I appear to be 10 times higher than the most magnesium-enhanced stellar systems discovered to date , and suggests that the chemical enrichment of this object was dominated by core-collapse supernovae .
Intriguingly , this breaks the canonical relation between [ Mg/Fe ] and star formation time-scale .
With a measured velocity dispersion of 56 \pm 10 km s ^ { -1 } , DGSAT I also shows a high mass-to-light ratio , which indicates that it is highly dark matter-dominated .
The metal-poor conditions of DGSAT I may have enhanced the formation of massive stars , while at the same time , additional mechanisms are needed to prevent iron-rich yields from being recycled into stars .
These results suggest that some ultra-diffuse galaxies could have experienced chemical enrichment episodes similar to the first building blocks of galaxies .