The Bostrychia tenella species complex: morphospecies and genetic cryptic species with resurrection of B. binderi

Abstract:

The question of whether morphological differences observed in specimens is due to multiple species or one variable species has always caused problems for taxonomists. The most recent taxonomic treatment of the ‘Bostrychia tenella species complex’ suggested that much of the morphological variation represented a single highly variable entity. We used molecular data from all three genomes to clarify the phylogeny, species status and phylogeography of samples collected worldwide and also in sympatry of this complex. Our data strongly support five genetic species in this complex, but only three morphological entities were recognized. The first, divided into two genetic species, fits characters associated with B. binderi, occasionally possessing short monosiphonous determinate laterals but lacking them most of the time. We therefore resurrect B. binderi, even though we could not assign a name to either of the two genetic species, as we are missing molecular evidence from the type specimen. One genetic species was morphologically recognized as B. montagnei. Another lineage consisted of the two genetic species that fall into a new circumscription of B. tenella, with long monosiphonous determinate laterals. Again we were unable to assign either of these two lineages to a type, nor could we find morphological differences between the two lineages. Many of the genetic species have worldwide distributions, except for B. montagnei, which appears to be restricted to the Americas. Our molecular-assisted taxonomy has helped clarify some of the morphological variation within the B. tenella species complex into three named species, but two cryptic species were still recognized that remain morphologically cryptic.

Key Words::

• Bostrychia tenella
• cox2–cox3 spacer
• Large-subunit ribosomal DNA
• Phylogeny
• rbcL
• Rhodomelaceae
• Rhodophyta
• RuBisCo spacer
• Species delimitation

ACKNOWLEDGEMENTS

We thank staff of the Royal Botanical Garden Melbourne herbarium for help with B. binderi type specimens. The following people were helpful in collections: Rosario Braga (Brazil), Nida Calumpong (Philippines), Judy Connor (Panama), John Huisman (Australia), Jhoana Larrea (Cuba), Chris Lobban (Guam) and Laurie Sullivan (Belize). Long-term financing for this work was provided through personal funds of J.A.W. and from the Australian Research Council, Australian Biological Resources Study and Hermon Slade Foundation grants to J.A.W./G.C.Z.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/15-005.1.s1.