Pugio Evolution

[arklore70]

I have a question in regards to the pugio.

In reading Bishop and Coulston as well as D'Amato and Sumner.

Once the pugio evolves past the Republican period we begin to see Type A, B and C Blades as well as Type A and B scabbards as I understand it.

Are these blades and scabbards developed and used simultaneously in the 1st Century and early Second Century, or does one proceed the other in development and usage?

For examaple, does the Leeuwen Pugio proceed the Melun Pugio or are they roughly developed in the same time, or is there just not enough evidence to even make a guess at this?

I could not find anything on the search engine.

Thanks,
R/