Abstract Detail

Systematics Section/ASPT

Ballard, Harvey [1], Zumwalde, Bethany [2], Gahagen, Benjamin [3], Roth, Todd [4].

Are we missing species diversity in the acaulescent blue violets?

More than a century of investigation and numerous studies have focused on the taxonomically bewildering acaulescent blue violets (Viola subsection Boreali-Americanae). Largely unrestricted hybridization, complex local and regional phenotypic variation, and emphasis on different features or species concepts have led to wildly divergent treatments of taxa. In the most recent treatments, species concepts employed did not accommodate the possibility of intergenomic recombination or hybrid speciation as mechanisms of species formation. Considering new evidence of an ancient allodecaploid origin for the Boreali-Americanae, numerous reports of interspecific hybridization, and early documentation of trait segregation in later-generation hybrid derivatives, intergenomic recombination or hybrid speciation cannot be ruled out. Species concepts should permit recognition of evolutionary products from these processes as distinct species; and evidence used should be capable of distinguishing recombinant species, plesiomorphic species or homoploid hybrid species from recurrently produced de novo hybrids. We present highlights from ongoing macromorphological, micromorphological and genetic investigations (using nuclear microsatellite markers and chloroplast DNA sequences) on cut-leaved species groups in the Boreali-Americanae. Examinations of variable broadly delimited species suggest that these are assemblages of somewhat geographically and ecologically differentiated cryptic species, with distinctions obscured by substantial local hybridization involving unlobed species. Intensive studies in Virginia and North Carolina have also revealed other narrowly endemic new species. Collectively, these studies hint that our understanding of species diversity and taxon delimitation in the Boreali-Americanae, especially for the central and southern Appalachians and southeastern states, is still inadequate. They also indicate that methodologies previously used to distinguish between de novo hybrids and other evolutionary products deserving of species status may not, of themselves, be up to the task without DNA-based evidence.

1 - Ohio University, Department of Environmental and Plant Biology, 315 Porter Hall, Athens, OH, 45701, USA
2 - Ohio University, Environmental And Plant Biology, 618 Carriage Hill Dr, Athens, OH, 45701, USA
3 - Ohio University, 317 Porter Hall, Athens, OH, 45701, USA
4 - Ohio University, Biological Sciences, Athens, OH, 45701, USA

Keywords:
Viola
Species delimitation
Microsatellites
endemic
cryptic diversity
new species.

Presentation Type: Oral Paper:Papers for Sections
Session: 19
Location: Salon 9/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 1:45 PM
Number: 19002
Abstract ID:889
Candidate for Awards:None