Museum collections are essential for understanding biodiversity and next-generation sequencing methods (NGS) offer new opportunities to generate genomic data on specimens of extinct species for phylogenetic and other studies. Hesperelaea is a monotypic Oleaceae genus that was collected only once, 140 years ago on Guadalupe Island, Mexico. This lineage is almost certainly extinct, and has been considered an insular paleoendemic of unknown relationship within subtribe Oleinae. Here, a genome skimming approach was attempted on the H.palmeri specimen to generate genomic data in order to interpret the biogeographic history of Hesperelaea in a phylogenetic framework. Despite highly degraded DNA, we obtained the complete plastome, the nuclear ribosomal DNA cluster (nrDNA), and partial sequences of low-copy genes. Six plastid regions and nrDNA internal transcribed spacers were used for phylogenetic estimations of subtribe Oleinae, including data from previous studies. Bayesian and maximum likelihood phylogenies strongly place Hesperelaea within an American lineage that includes Forestiera and Priogymnanthus. Molecular dating suggests an Early Miocene divergence between Hesperelaea and its closest relatives. Our study thus confirms that Hesperelaea was a paleoendemic lineage that likely predates Guadalupe Island, and provides a notable example of the high potential of NGS for analyzing historical herbarium specimens and revolutionizing systematics.

Ecological and evolutionary theories have proposed that species traits should be important in mediating species responses to contemporary climate change; yet, empirical evidence has so far provided mixed evidence for the role of behavioral, life history, or ecological characteristics in facilitating or hindering species range shifts. As such, the utility of trait-based approaches to predict species redistribution under climate change has been called into question. We develop the perspective, supported by evidence, that trait variation, if used carefully can have high potential utility, but that past analyses have in many cases failed to identify an explanatory value for traits by not fully embracing the complexity of species range shifts. First, we discuss the relevant theory linking species traits to range shift processes at the leading (expansion) and trailing (contraction) edges of species distributions and highlight the need to clarify the mechanistic basis of trait-based approaches. Second, we provide a brief overview of range shift-trait studies and identify new opportunities for trait integration that consider range-specific processes and intraspecific variability. Third, we explore the circumstances under which environmental and biotic context dependencies are likely to affect our ability to identify the contribution of species traits to range shift processes. Finally, we propose that revealing the role of traits in shaping species redistribution may likely require accounting for methodological variation arising from the range shift estimation process as well as addressing existing functional, geographical, and phylogenetic biases. We provide a series of considerations for more effectively integrating traits as well as extrinsic and methodological factors into species redistribution research. Together, these analytical approaches promise stronger mechanistic and predictive understanding that can help society mitigate and adapt to the effects of climate change on biodiversity.