It doesn't. The spider's name is 'Number 16'. It could be any alphanumeric string.
Anyway, only humans use names. Is "Brenda" a human or a spider? Sure, you can answer this now - but can you answer it in another 10 years?
It also doesn't tell us that it's one of at least 16 data points. From the article we only know that it was the 16th spider they recorded as being present but we don't know that any of the other 15 made it into the study. The fact that you're reading something we don't know into it from the name #16 actually highlights a failing in this system for me. Surely if it matters to you then you'll be reading the study which will these details explicitly.