Conservation Genetics of a Critically Endangered Limpet Genus and Rediscovery of an Extinct Species

A third of all known freshwater mollusk extinctions worldwide have occurred within a single medium-sized American drainage. The Mobile River Basin (MRB) of Alabama, a global hotspot of temperate freshwater biodiversity, was intensively industrialized during the 20(th) century, driving 47 of its 139 endemic mollusk species to extinction. These include the ancylinid limpet Rhodacmea filosa, currently classified as extinct (IUCN Red List), a member of a critically endangered southeastern North American genus reduced to a single known extant population (of R. elatior) in the MRB.We document here the tripling of known extant populations of this North American limpet genus with the rediscovery of enduring Rhodacmea filosa in a MRB tributary and of R. elatior in its type locality: the Green River, Kentucky, an Ohio River Basin (ORB) tributary. Rhodacmea species are diagnosed using untested conchological traits and we reassessed their systematic and conservation status across both basins using morphometric and genetic characters. Our data corroborated the taxonomic validity of Rhodacmea filosa and we inferred a within-MRB cladogenic origin from a common ancestor bearing the R. elatior shell phenotype. The geographically-isolated MRB and ORB R. elatior populations formed a cryptic species complex: although overlapping morphometrically, they exhibited a pronounced phylogenetic disjunction that greatly exceeded that of within-MRB R. elatior and R. filosa sister species.Rhodacmea filosa, the type species of the genus, is not extinct. It persists in a Coosa River tributary and morphometric and phylogenetic analyses confirm its taxonomic validity. All three surviving populations of the genus Rhodacmea merit specific status. They collectively contain all known survivors of a phylogenetically highly distinctive North American endemic genus and therefore represent a concentrated fraction of continental freshwater gastropod biodiversity. We recommend the establishment of a proactive targeted conservation program that may include their captive propagation and reintroduction

Separation of metal Bis(2-hydroxyethyl)dithiocarbamate complexes by micellar electrokinetic capillary chromatography

A method was developed for the separation of CdII, PbII, PtII, CoII, NiII, BiIII, CrII, CuII and HgII bis(2-hydroxyethyl)dithiocarbamate (HEDTC) complexes by micellar electrokinetic capillary chromatography. The complexes were formed by pre-capillary reaction of the metal ions with an excess of the ligand and then separated using a 100 mM borate buffer (pH 9.2) containing 4% methanol (v/v), 10 mM sodium dodecyl sulfate and 0.1 mM HEDTC, with detection at 254 nm. All the metal complexes, except PtII and PbII, were baseline resolved and separation was achieved in under 7 min. Detection limits were in the range 22 to 133 ppb

Simultaneous analysis of lead, mercury and selenium species by capillary electrophoresis with combined ethylenediaminetetraacetic acid complexation and field-amplified stacking injection

10.1002/(SICI)1522-2683(19990801)20:12<2475Electrophoresis20122475-2483ELCT