Phylogenetic instability in a clade of the conifer family Podocarpaceae (Order Araucariales)

ESCAPA, IGNACIO H.; AAGESEN, LONE; ANDRUCHOW-COLOMBO, ANA; AMBROSIO TORRES

Berkeley

Encuentro; XXXVIII Meeting of the Willi Hennig Society; 2019

Willi Hennig Society

The Podocarpaceae constitute the second most diverse conifer family in the world, with ca. 198 extant species within 18 genera. Recent molecular phylogenetic analyses of the Podocarpaceae retrieve two main clades for the family: a tropical clade that encompasses nearly 80% of its extant species diversity, contained within 11 genera, and a prumnopityoid clade with the remaining 20%, within 7 genera. The intergeneric relationships within the tropical clade have remained relatively stable among different studies. However, this has not been the case for the genera of the prumnopityoid clade, where different studies retrieve different groupings of taxa. Therefore, our objectives were (1) to build a molecular matrix integrating a large number of available DNA sequences, (2) to test the topological differences among the results of of different partitioned data analyses, and (3) to try to identify the main possible causes of the mentioned phylogenetic instability of the prumnopityoids. Some of the hypothesized causes for the reported instability of this group are long branch attraction (LBA), rapid radiations in deep time (too short branches), conflicting evidence provided by different partitions of the data, and lack of information (missing data) of the sampled taxa. We built a DNA matrix for the family with 11 molecular markers (11044 DNA characters, 26.5% informative) from nucleus and chrloroplast. Our taxon sampling includes 158 species and 8 subspecies of the Podocarpaceae, 35 Araucariaceae species, and Cryptomeria japonica (Cupressaceae) for rooting. The strict consensus of the most parsimonious trees recovers the monophyly of all the genera within Podocarpaceae, and that of the large clades recovered in previous studies. Also, within the prumnopityoid clade we recover a previously defined scale-leaved clade. Different partitions of the matrix result in a diverse pool of contrasting topologies for the prumnopityoid clade, suggesting that there is conflicting evidence provided by different data partitions.