Multiple states tied

[ALVARO QUESADA GARCIA]

Hi Nick and everyone,

I hope this email finds you well. I am a PhD student and I am not an expert using BioGeoBEARS or R, so I apologize if my question is too obvious. I am also not a native English speaker, so I may not express myself well in English.

I am performing an ancestral range estimation with the DEC+j model, temporally stratified, using:

• phylogeny of 95 species
• 10 areas
• max_range_size=8
• dispersal multipliers matrix (with different dispersal probabilities between areas, but never probability 0)
• 5 temporal strata in which the different areas are appearing

The problem I am having is that in each node of the phylogeny I get very low and similar probabilities for many states. In this way, in almost all the nodes there are 10 states (corresponding to the 10 areas) that have the same probability, as they appear in time (I attach an image where it is better understood). This does not make much sense biogeographically speaking, because it cannot be that there is the same probability for all the areas, and then it would not make sense to perform the BSM.

I do not understand why this happens. I have done a similar analysis, using the same matrices of allowed areas, dispersal multipliers and temporal stratification, with two other phylogenies (with more than 200 species), and the results were consistent. Therefore I assume that the problem is in this phylogeny and/or in the range of areas of each species. But this is an assumption, I don't know what the problem really is.

Thank you very much in advance

Best regards,