Disentangling a Knot of Ribbon Worms: Recent Progress in Nemertean Systematics
TUESDAY 24th July, 12pm
Neil Chalmers Science Seminar Room (DC.LG16)
Department of Life Sciences, NHM
The assemblage of animals known as “ribbon worms” (phylum Nemertea) is understudied despite their evolutionary significance and ecological success. Their phylogenetic position has occupied a nexus in hypotheses of metazoan evolution; they are undoubtedly protostomes possessing a trochophore larva, yet a sister group remains uncertain. Nemerteans are present in every marine biotope and have repeatedly colonized freshwater, terrestrial and parasitic habitats. They are primarily predators that can impact community structure; some species may be particularly voracious, capable of adversely affecting the output of crab fisheries, or have been implicated in the destruction of clam-flat populations. Despite their evolutionary and ecological significance, 95% of recent biodiversity surveys simply report them as “Nemertea sp.” Identification can be difficult as many species require careful histological examination of transverse sections just to determine class. A robust and modern phylogenetic-based classification has been elusive on account of this, hindering progress with respect to species discovery, revisionary systematics and evolution-based hypotheses of character change. After reviewing highlights of nemertean natural history and diversity, I will discuss our recent, successful efforts to improve upon our understanding of ribbon worm phylogenetics and its implications.
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