According to logic, I believe Yehuda "Juda" and Yankov "Jankef" had another sibling Mortka. I'm fairly well convinced of this, but this is only my gut feeling.
Here is why I feel so strongly about it.
I started with the tree as assembled from family history and my wife's research and conversations with distant family members.
Then I added in names from the ship manifests, etc. to fill in gaps and get a picture of the family.
Then I went to www.jewishgen.com (which probably is the ONLY reliable source of information from Poland) and looked at all the names. I put them into a spreadsheet and finagled the names to make them fit, for example, my GF Israel was listed as Srul, his sister Leah was listed as La, his brother Abraham was Avram and Isaac was listed as Icek. It's a bit of a jigsaw puzzle with the names, piecing them all together, but this was the way the family's names read.
Then, using the same finagling of the names, I plugged all the other names I found into the spreadsheet and matched everyone up. At this point, I was left with 5 names unaccounted for.
Since all the other Dantos/Dantowicz family members linked up, the odds that these 'stragglers' weren't siblings or immediate family members were very remote. I found no other Dantos families, so I believe Mortka was a sibling. Given that the birth year for Mortka was around the time of the births of Yankov and Yehuda, it seemed logical that he was their brother.
Furthermore, he might have died long before my GF was born (1890) so my GF, who was our family historian, might not have known about Mortka (his uncle) or possibly just never mentioned him.
At this point, there were only four other family members unaccounted for, Dworja, Berek (two listings) Ruchl and Majer (two listings), I assued that Mortka and Fajga had a family (why not? everyone else did) and these remaining people were part of their family.
Here are the problems...
*Brana Dobra Dantus - Dwory Dantos
I found a listing for Brana Dobra Dantos d.1875 and separate one for Dwory Dantos b.1817. Since I can't tie Brana Dobra in with any one else there could be one of two scenarios.
**First (less likely). She died at a young age. Given that all the other birth records were chronicled during that time frame, the likelihood of her birth being left out is very remote, no? Then who is she?
**Second (more likely) I'm going to go out on a limb here, but considering that the two records (Dwory's birth and Brana Dobra's death) were 58 years apart and also that people's given names were swapped with their middle names, changed, misheard or misspelled (for example, my GF Srul), I believe these two women might be the same person. Our tree had my 2nd GGM's name as 'Debrorah' ... and Dobra is close to that sound. Even thought the names Dwory and Dobra are different, they aren't that dissimilar? If they were the same person, she would have had a 58 year life span, which was probably appropriate for that time period.
*Majer (there were three, one was Yankov and Yehuda's father, this discussion is about two younger children)
Majer, the father of Yankov, Mortka and Yehuda, died. Shortly there after, two of his sons, Yankov and Mortka, both recently married, honor the memory of their father by naming their first born sons Majer. Since no one had any record of Majer in my family, I assumed Majer, the younger, must have died before my GF or his siblings know about him. I assumed he was part of Yankov's family and not Yehuda's because, Yehuda had a son after 3 years of marriage. If Yankov wasn't the father of Majer, that would imply that Yankov waited six years before having his first child. Back in those days folks had lots of babies and didn't wait too long to start. Ergo, I listed Majer as Yankov's son. Just guesswork, but I think it makes sense. Unfortunately, with no other information on either of the younger Majers so I have to assume they died young.
*Berek.
There were three listings for him, b1884...d1885 ... b1888. This is where I have a problem. The logic of the dates would imply that there was a Berek born (presumably into Mortka's family). This child died and Mortka's brother Yehuda honors his nephew's memory by naming his son (b. 1888) Berek. This child became Benjamin Dantowitz. This makes sense, except for the fact that Benjamin's census data and draft card put his year of birth in 1884. Further, his brother Morris Dantos/Moe Dantow was born in 1888 making it unlikely that Berek/Benjamin was also born in 1888.
The only guess I can make is that Benjamin was told the wrong year of his birth (1884 instead of 1888). Other than that, I am completely stumped.