Geodispersal of the typical Neotropical cenocron from South America to the Mexican Transition Zone: a cladistic biogeographical test

Analysis of the biotic assembly of the Mexican Transition Zone (MTZ) is challenging because of the convergence of taxa with different origins and biogeographical histories. The typical Neotropical cenocron corresponds to genera widespread in South America that might have dispersed to the MTZ in the Pliocene-Holocene. It has been exemplified with distributional patterns of several plant and animal taxa; however, their historical congruence has not been tested. We examined the historical relationships among the areas of endemism where Typical Neotropical taxa are found through a cladistic biogeographical analysis to determine whether they have dispersed simultaneously, showing a geodispersal pattern. We searched for Neotropical clades that dispersed to the MTZ from the Pliocene to the present. The distribution of nine animal clades in seven areas of endemism was analysed by cladistic biogeography. Redundant areas and widespread taxa were treated with paralogy-free and transparent methods. Patterns of area relationships were searched using a parsimony analysis of paralogy-free subtrees. The parsimony analysis found a single resolved tree showing a general pattern of area relationships: (Chacoan ((South Brazilian (Boreal Brazilian + Lesser Antilles)), (South American Pacific (Mesoamerican-Central America + Western Mexico)))). Distributional and phylogenetic information on the groups analysed contrast with a previous cladistic biogeographical analysis that has shown different area relationships, thus supporting the general hypothesis of a geodispersal event of the Typical Neotropical cenocron in the MTZ. Additionally, the analysis provided evidence of vicariant events related to the lifting of the Northern Andes and climatic changes during the Pleistocene.

Automated summary

The analysis reveals that the Typical Neotropical taxa have dispersed from South America to the Mexican Transition Zone from the Pliocene to the present. Additionally, evidence of vicariant events related to the lifting of the Northern Andes and climatic changes during the Pleistocene were also found.