The 1823 death entry in the church records of the Evangelical church in Wohlmuthausen, Thuringen, Germany, list her name as Anna Catharina Trautvetterin.
That’s how I should transcribe it because that’s what it says.
Do I have a new surname for this family? Do I have a new spelling? Not really. In fact, I have Trautvetter–just a feminine version that was used in the area during this time period. Names are always transcribed as they are written and they are analyzed in context. Anna Catharina’s entry is not the only one for a female on the page of entries that has a last name ending in “in.” Her entry is typical, not atypical.
That’s something one does not discover if one only looks at the item of interest and does not give any thought to cultural and linguistic patterns.