Genealogy Lesson on Last Names When Researching

One of the biggest lessons I can teach others is understanding last names and how they can lead you down the wrong path, very quickly. I’ll provide two examples as these are actually a reality for everyone and not just some.

One of the biggest misconceptions in researching is that if the last name is found in the town you or your family comes from, then we must be related via that last name. However, this is a huge fallacy that has led to many erroneous family trees on websites such as Ancestry. People assume that because you match on the last name, that is how you are related. Then people perpetuate this false belief by copying the tree information without validating it and not identifying your real ancestors. Remember, genealogy is about finding out the truth and not about just adding names to a tree.

False beliefs even extend to when finding individuals on your DNA list and assuming relationships with matches on your DNA results. This post will speak to both types of cases. The first example is on the Betancourt line out of the Trujillo Alto, Puerto Rico and neighboring municipalities in Puerto Rico. There is a huge fallacy that every Betancourt that is from Trujillo Alto region are all related. Nothing can be furthest from the truth!

Case 1: Betancourt

Years ago I took interest in researching the Betancourt line because my father’s maternal great grandmother is Valentina Diaz Betancourt. Note that there is also a Valentina Betancourt Diaz. These two women are actually double first cousins. How so? Well, their parents are siblings to each other. Both families had daughters the same year and decided to name them both Valentina; do not mix these two women up.

I wanted to know more about my Valentina, and via research, I was able to locate via records in Puerto Rico and Spain that she is one of the Betancourt Asencio decendants and that her Asencio line arrived via a soldier. His family migrated to Puerto Rico from Lerma, Burgos, Castilla-Leon, Spain.

On the Betancourt line, people assume that all of the Betancourts are related in the Trujillo Alto, Carolina, Gurabo, Juncos, San Juan, and Loiza regions. While the majority came from the Canary Islands, they came from different islands and during different periods in time. In addition, the last name was taken on by the Guanches after the Spanish conquest.

I descend from Juan Diego Espanto Betancourt, who was from Gran Canaria, Canary Islands. Diego arrived in Puerto Rico from the Canary Islands sometime in the mid-1700s and had one surviving son, Rafael.

Then we have Pedro Roque Reyes Garcia and his wife, Josefa Adelia Betancourt. They are both from Lanzarote, Canary Islands. Roque and Josefa arrived sometime in the early 1800s. There are other Betancourt families that have also arrived to the region.

However, both of these Betancourt families are not related. Now there is a subset that does descend from both lines when they marry, but it does not make us all related to Pedro and Josefa. You can read more about the Betancourt families here on the website as I’ve written about them and delved deeper into the false non-sourced or nonvalidated information found on trees on Ancestry.

Case 2: Perez

So this one is an interesting one and should be a lesson to all the newbies and seasoned researchers out there. It is not as simple as screaming we are related via the last name because of shared DNA. If you think that that is how it works, you are seriously going to mess up your family tree and wind up cutting down the entire tree when you discover the truth. Do your research right and take your time. Do not simply take the word of another but seriously look at the data as you will uncover mistakes if you know what you are doing. Ask for documentation and revalidate it yourself.

So an individual approached me and asked if I can assist them with locating a parent. This person has the parent’s full name and I was provided with the last name of Perez. In addition, they also provided me some background information and approximate age for the person. Lastly, they advised that they had narrowed it down to a specific line as they had two second cousins with the last name of Perez. My thought, oh this should be pretty easy to figure out. As I glanced at these Perez matches, my thought was, yup they are indeed looking like solid second cousins and started digging through their trees, but something was not right with the information. I walked away temporarily from this case as I was concentrating on another case in helping two other individuals. Walking away temporarily was actually a good thing.

When I came back to this case, I decided to trash all the information provided to me and start off fresh as if I did not know their father’s name. And lo and behold! JACKPOT!!! It turned out that it was a mere coincidence that there was a second cousin with the Perez last name. Since the island is riddled with endogamy, I knew that there is no possible way that they connect on the Perez line as the numbers were too low. It turns out that these second cousins were true second cousin as I uncovered their connection as there were other individuals that were all descending from a specific line and second cousins to each other and the individual.

These second cousins were actually second cousins through the Flores line and not the Perez line. The above images are trees of those second cousin. I was able to figure it out by connecting and correcting names on these individuals’ trees. None have dug back and not all even have the correct last name or at times have the nickname to the parents. This research alone took me about 3 weeks worth of digging to figure out the individual’s one set of great grandparents. Their names are Felipe Flores Davila and Juana Diaz Morales. This couple lived in Carolina, Puerto Rico. When I provided the evidence and information to the individual, they were blown away and I provided details they were obviously ignoring because they were stuck on the Perez last name.

While I am still researching this person, one thing is sticking out, that their father’s last name of Perez may not be his last name. Potentially he is a Non-Parental Experience himself, or since I have not completed researching all the children of this couple, someone married a Perez. I do have a hot clue and that is the very strong second cousin that came in at 491 centimorgans (cMs) is double related somehow, but my current theory is that their father is a Perez only by name but not a descendant of that last name.

I am still continuing the research for this individual but wanted to share why people should not be assuming that because you have a common last name, that that is the way you’re related; especially if you are in the same town. I see it all the time in the groups, “I find no common last names so they must not be related” statements. I hope these two examples provide you with a better understanding that last names you match with is not necessarily the clue, but that the DNA is factual and holds the answers if you’re willing to work with it.