![]() With approximately 755 species, Australia’s reptile diversity exceeds that of any other country for this group 8. ![]() As an island continent, isolated by sea from other vegetated continents for 65 My, it is well known for its endemic fauna and flora. DNA sequencing of name-bearing type specimens is thus regarded as the gold standard for taxonomy 7, because it enables unambiguous assignment of extant populations to the named entity or enables a clear distinction between newly discovered forms and those that have already been described.Īustralia is the smallest of all continents and congruent with the nation of the same name. Although still not routine, generating historical DNA data has become feasible on a large scale 3, 4, 5, 6. Generating DNA sequences from historical material has been a major challenge, but the advent of high-throughput parallel sequencing and ancient or trace DNA (aDNA) approaches have fundamentally altered the situation. Uncertainty over the identity of new forms in comparison to historical type specimens can lead to considerable confusion and taxonomic instability. As a consequence, the accelerating rate at which new biodiversity is being documented is somewhat disconnected from the taxonomic work that has taken place before. Type specimens are either fixed in formalin, a process that cross-links the DNA with associated proteins and renders the DNA inaccessible, or they are preserved in such a way that DNA is degraded. At the same time, DNA technology presents a challenge because rarely can the new information be obtained for types used by previous taxonomists. Name-bearing type specimens for each named species, and making the types widely available through museums, are thus the foundation of taxonomic enquiry.ĭNA technologies have revolutionized taxonomy by bringing to the table a large suite of new characters to complement those available from morphological analysis. Often they must gather that new information from specimens used by previous generations of taxonomists in making their determinations 2. Each generation of taxonomists must deal with new information, brought about by advances in technologies and the discovery of new informative traits. According to the International Code of Zoological Nomenclature, the name of any new species is unambiguously linked to and defined by the so-called name bearing type specimen. Each new taxon is formally described by identifying one or more traits that consistently distinguish it from other closely related taxa. Taxonomy has as its foundation the concept of diagnosability. Taxonomic research is arguably more important today than it has been at any time in its history. We are unaware of what it is we are losing. ![]() Notwithstanding the urgent need to address the causes of this catastrophic decline in biodiversity, we must understand that many species could be lost before they or their significance have been recognised by science. Species extinction is occurring at an unprecedented rate 1, brought about by human-induced habitat loss, overexploitation for economic gain, and climate change. Together with previously published nuclear genomic data, our study provides evidence for multiple old mitochondrial introgressions. We resolve a number of important issues that have confused the taxonomy of this family, and analyse the mitogenomes of the types and those of fresh material to improve our understanding of the phylogenetic relationships of this morphologically conservative group. Here we apply high-throughput parallel sequencing and sequence baiting to reconstruct the mitogenomes from 18 type specimens of Australasian side-necked turtles (Chelidae). Consequently, the challenge of sequencing highly degraded DNA from historical types becomes an inevitability to resolve the very many taxonomic issues arising from, by modern standards, poor historical species descriptions leading to difficulties to assign names to genetic clusters identified from fresh material. New advances in technologies and the discovery of new informative traits must be matched with previous taxonomic decisions based on name-bearing type specimens. Diagnosability is central to taxonomy as are type specimens which define taxa.
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