Explorando a lacuna Darwiniana em Fabaceae (Leguminosae) na Bacia dos Rios Tocantins-Araguaia

Abstract

This study assessed the phylogenetic shortfall of legumes in the Tocantins-Araguaia Basin using the Phylogenetic Diversity Deficit (PDd) quantified at the species level (PDdSp) and the grid-cell level (PDdL). After data consolidation and taxonomic validation, the final checklist comprised 1224 species. PDdSp showed strong dependence on phylogenetic insertion: 59.6% (n = 729) of species required insertion into the reference phylogeny, yielding clustered positive values (median = 0.0028; IQR = 0.0016–0.0040; maximum = 0.0193) and marked concentration in a few megadiverse genera. Spatially, PDdL was highly heterogeneous when derived from point occurrences (median = 0.444; range = 0-1), with extreme values associated with low-richness cells, but became more stable when derived from distribution polygons (median = 0.342; IQR = 0.321–0.390). Genetic data availability in NCBI was broad yet uneven: 82.2% of species had at least one record (total of 158 745 entries), 17.8% lacked sequences, and among species with data the median was 6 records, with extreme concentration in a few taxa. Phylogenetic hurdle models indicated that the probability of PDdSp = 0 increases strongly with the number of genomic DNA sequences and with scientific output, whereas the magnitude of positive PDdSp was not explained by the covariates (being dominated by insertion rules). For PDdL, point-based models showed that cells composed of better-studied species and, under median aggregation, with greater genomic DNA availability tend to exhibit lower deficits; in polygon-based models, spatial dependence was dominant and additional effects were small. Overall, the phylogenetic deficit is substantial, lineage structured, and aligned with gradients of information accumulation. These results identify taxa and areas where deficits are concentrated and provide guidance to prioritize sampling, sequencing, and data curation, reducing phylogenetic incompleteness and strengthening ecological and conservation inferences in the basin.