Several terms redirect here. For species-group names, see International Code of Zoological Nomenclature. For individuals of different species grouping together, see Mutualism (biology)#Service-service relationships. For the principles of hiding, see Crypsis. For supposed creatures, see List of cryptids. For another use of physiologic race, see Race (biology)#Physiological race.
The butterfly genus Heliconius contains some species that are extremely difficult to tell apart.
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use.
Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as bacterial strains or plant varieties), which may be a complex ranking but it is not a species complex. In most cases, a species complex is a monophyletic group of species with a common ancestor, but there are exceptions. It may represent an early stage after speciation in which the species were separated for a long time period without evolving morphological differences. Hybrid speciation can be a component in the evolution of a species complex.
Species complexes exist in all groups of organisms and are identified by the rigorous study of differences between individual species that uses minute morphological details, tests of reproductive isolation, or DNA-based methods, such as molecular phylogenetics and DNA barcoding. The existence of extremely similar species may cause local and global species diversity to be underestimated. The recognition of similar-but-distinct species is important for disease and pest control and in conservation biology although the drawing of dividing lines between species can be inherently difficult.
In biology, a speciescomplex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between...
problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a speciescomplex of hundreds...
Burkholderia cepacia complex (BCC) is a speciescomplex consisting of Burkholderia cepacia and at least 20 different biochemically similar species of Gram-negative...
ideal ring species." The following list gives examples of ring species found in nature. Some of the examples such as the Larus gull complex, the greenish...
recognized species in this genus, and the species are now organized into speciescomplexes that usually have the name of their most widely known species. The...
characteristics of the breeding season they are born into. The C. pipiens speciescomplex consists of: C. pipiens C. p. pallens – human-biting (Northeast Asia)...
American Trillium species. These species hybridize in the wild, which has led some researchers to group them into a speciescomplex, specifically, a syngameon...
speciescomplex and superspecies for convenience as extra, but unofficial, ranks between the subgenus and species levels in taxa with many species, e...
Exosome complex, a multi-protein intracellular complex Protein complex, a group of two or more associated polypeptide chains Speciescomplex, a cluster...
currently accepted scientific name for the species. As traditionally defined, the Nile monitor is a speciescomplex. The ornate monitor (V. ornatus) and West...
elevate the genetic variant MAC-A, included in the Mycobacterium avium complex, to species rank as Mycobacterium chimaera sp. nov". International Journal of...
albatross, it forms the wandering albatross speciescomplex. When the complex was split into four species, the English name of the nominate form was changed...
defence. Slow worms have been shown to be a speciescomplex, consisting of 5 distinct but similar species. Anguis fragilis was traditionally divided into...
Eryngium plants (English names: 'sea holly' or 'eryngo'). P. eryngii is a speciescomplex, and a number of varieties have been described, with differing plant...
additional species are recognized – in particular in the A. arvensis speciescomplex – and placed here, such as A. aestivalis, A. augustus, A. caroli, A...
Collectively, these fishes are often referred to as a speciescomplex, the Coregonus artedi complex, or as Coregonus artedi sensu lato (broad sense). Commercial...
76 recognized species in this genus. The currently described Betta species can be grouped into speciescomplexes: B. akarensis complex: Betta akarensis...
ago, with the appearance of Proailurus and Pseudaelurus. The latter speciescomplex was ancestral to two main lines of felids: the cats in the extant subfamilies...
A genetic study published in 2017 indicates that C. striata is a speciescomplex. It is a bony fish with endoskeleton ribcage, grows up to a meter in...
different species (B. plicatilis and B. rotundiformis). DNA sequencing studies in 2002 revealed Brachionus plicatilis to be a cryptic speciescomplex comprising...
penguin (/ˈdʒɛntuː/ JEN-too) (Pygoscelis papua) is a penguin species (or possibly a speciescomplex) in the genus Pygoscelis, most closely related to the Adélie...
et al. (2015). "Recognition of seven species in the Cryptococcus gattii/Cryptococcus neoformans speciescomplex". Fungal Genetics and Biology. 78: 16–48...
that Anabas testudineus is a speciescomplex, with the binomial name applied to what are actually several different species. With further study, populations...
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