Iberian Spanish (IBS) regional populations, and ran multidimensional scaling on them (left). Most of the populations form a tight cluster, with Basques and Canary Islanders having averages further removed from the main cluster.
It should be noted that the Canarias sample consists of only two individuals (big red dots): one removed from the main cluster, one in the midst of individuals from Castilla Y Leon (small red dots).
MCLUST analysis using 1 dimension, reveals 2 clusters: one consisting of Pais Vasco individuals (blue dots), the other of everyone else, with one Aragonese and one Cantabrian individual showing mixed probabilities between the two clusters.
The overall impression is that there may be additional population structure here (e.g., for Canarians or Galicians), but the sample sizes are not sufficient to make additional clusters unambiguously evident, except in the case of Basques vs. non-Basques.