ౘ & ౙ

Telugu has these sounds ౘ t͡s and ౙ d͡z Which are not found in other Dravidian languages or Sanskrit afaik, except for Marathi where the sounds are not represented with a seperate letter.

In Telugu, these dental letters were usually represented by చ and జ (ca & ja) until Charles Philip Brown (a British language scholar) came up with two new letters to make a distinction from the rest of the syllabary, in his Telugu-English dictionary.

So, how do these sounds only exist in Telugu and Marathi and not in any other languages? Is this an influence of Maharashtri Prakrit on Telugu or is it the other way around ?