Wikipedia provides a very detailed page on the origins of the domestic dog, but this fact does not seem to be present there. Google searches for terms such as "most recent common ancestor (MRCA) of dogs" didn't reveal any authoritative sources.
As Remi.b points out, the where and when of the ancestor of the domesticated dog is not well known.
Based on a review by Morell (2015), the ancestor of the domesticated dog (canis familiaris) was a now extinct wolf that gave rise to Fido 11,000 to 16,000 years ago. The author bases this conclusion mainly on data from Freedman et al. (2014). Interestingly, Freedman et al.'s data indicate that it was not the Gray Wolf (Canis lupus) that gave rise to Fido, which was long thought to be the one and only ancestor. The ancestral extinct wolf is thought to have give rise to present-day dogs, Dingoes and the Chinese, Israeli and Croatian wolf. The Golden jackal split off earlier, around 400,000 years ago.
Complicating the search for Fido's ancestor is the widespread occurrence of wolves and dogs, which makes it difficult to pinpoint the location of origin. Indeed, there is indication that canids were domesticated not once, but multiple times at different places, just like the domesticated pig was domesticated twice. Moreover, there is indication of gene flow between wolves and dogs after Fido split off, further blurring the available evidence (Morell, 2015).
A recent 2015 special issue on dogs and cats in Sci Am may shed more light on this, but I have to get to that. Will update this answer if appropriate!
From the wikipedia article you linked:
The origin of the domestic dog (Canis lupus familiaris or Canis familiaris) is not clear. Whole genome sequencing indicates that the dog, the gray wolf, and the extinct Taymyr wolf diverged at around the same time 27,000–40,000 years before present.
They cite Skoglund et al. 2015.
It seems that divergence between the grey wolf and the dog started at Taymyr (northern Russia) about 27,000–40,000 years ago. Therefore, the MRCA of all dogs and grey wolf today would have lived about 27,000–40,000 years ago. Tito et al. 2013 estimated canids fossils found in Europe were 39,000 years old. We currently don't have a better accuracy and we are not able to date the MRCA of all dogs with more accuracy than the MRCA of grey wolves and dogs.