Glossary Term: Cryptic Species

In scientific classification, a cryptic species complex is a group of organisms that are typically very closely related yet their precise classification and relationships cannot be easily determined by molecular phylogenetic studies. If lineage sorting has not yet been completed, members of a cryptic species complex widely share plesiomorphic haplotypes, because individual species have not yet evolved distinctive autapomorphic mutations. But usually, individual species within the complex can be separated by analysing data from multiple sources, such as by comparing polytene chromosomes, DNA sequence analyses, bioacoustics and thorough life history studies. They may be parapatric, are frequently sympatric, and are sometimes allopatric. Cryptic species complexes are not the same as populations undergoing speciation: they typically represent a situation where speciation has already broken the gene flow between populations, but where evolution has not progressed to a point where easily recognizable adaptations have taken place. Cryptic species that do not form a complex may be somewhat more distantly related and simply represent lineages that have been so successful as to require little evolutionary change, possibly coupled with parallel evolution. A famous example outside the realm of mycology can be seen in the Eurasian and Short-toed Treecreepers, perhaps the first cryptic species to be recognized as such. Other ornithologists refused to accept that more than one species was involved until Brehm presented his bioacoustic studies, which left no room for doubt. The European Treecreeper has since been found to be a very close relative of the Himalayan Hodgson’s Treecreeper, while the Short-toed Treecreeper is probably the sister species of the North American Brown Creeper. Cryptic species are also common in certain families of insects such as Chironomidae. A related concept is the superspecies. This is a clade of at least two more or less distinctive species with approximately parapatric distributions. Not all cryptic species complexes are superspecies, and vice versa, but many are.

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Created: 2019-06-23 14:31:01 CDT (-0400)
Last modified: 2019-06-23 14:31:01 CDT (-0400)