Species complex

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The butterfly genus Heliconius contains some species that are extremely difficult to tell apart. Heliconius mimicry.png
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.

Contents

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 are ubiquitous 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.

Definition

Systematics-of-treefrogs-of-the-Hypsiboas-calcaratus-and-Hypsiboas-fasciatus-species-complex-(Anura-ZooKeys-370-001-g009.jpg
At least six treefrog species make up the Hypsiboas calcaratus – fasciatus species complex. [1]
Karpassienet.jpg
The fly agaric comprises several cryptic species, as is shown by genetic data. [2]
Loxodontacyclotis.jpg
The forest elephant (shown) is the bush elephant's sibling species. [3]
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Mbuna cichlids form a species flock in Lake Malawi. [4]

A species complex is typically considered as a group of close, but distinct species. [5] Obviously, the concept is closely tied to the definition of a species. Modern biology understands a species as "separately evolving metapopulation lineage" but acknowledges that the criteria to delimit species may depend on the group studied. [6] Thus, many traditionally defined species, based only on morphological similarity, have been found to be several distinct species when other criteria, such as genetic differentiation or reproductive isolation, are applied. [7]

A more restricted use applies the term to a group of species among which hybridisation has occurred or is occurring, which leads to intermediate forms and blurred species boundaries. [8] The informal classification, superspecies, can be exemplified by the grizzled skipper butterfly, which is a superspecies that is further divided into three subspecies. [9]

Some authors apply the term to a species with intraspecific variability, which might be a sign of ongoing or incipient speciation. Examples are ring species [10] [11] or species with subspecies, in which it is often unclear if they should be considered separate species. [12]

The rubyspot damselfly Hetaerina americana is suspected to be a cryptic complex with at least one other species of rubyspot. Sparganium eurycarpum-Hetaerina americana-male perching.jpg
The rubyspot damselfly Hetaerina americana is suspected to be a cryptic complex with at least one other species of rubyspot.

Several terms are used synonymously for a species complex, but some of them may also have slightly different or narrower meanings. In the nomenclature codes of zoology and bacteriology, no taxonomic ranks are defined at the level between subgenus and species, [13] [14] but the botanical code defines four ranks below subgenus (section, subsection, series, and subseries). [15] Different informal taxonomic solutions have been used to indicate a species complex.

Cryptic species
Cryptic species are morphologically identical species. More generally, the term is often applied when species, even if they are known to be distinct, cannot be reliably distinguished by morphology. [16]
Sibling species
Also called aphanic species. This term, introduced by Ernst Mayr in 1942, [17] was initially used with the same meaning as cryptic species, [7] but later authors emphasized the common phylogenetic origin. [18] A recent article defines sibling species as "cryptic sister species", "two species that are the closest relative of each other and have not been distinguished from one another taxonomically". [19]
Species flock
Also called species swarm. This refers to "a monophyletic group of closely related species all living in the same ecosystem". [19] Conversely, the term has also been applied very broadly to a group of closely related species than can be variable and widespread. [20] Not to be confused with a mixed-species foraging flock, a behavior in which birds of different species feed together.
Superspecies
Sometimes used as an informal rank for a species complex around one "representative" species. [21] [22] Popularized by Bernhard Rensch and later Ernst Mayr, with the initial requirement that species forming a superspecies must have allopatric distributions. [23] For the component species of a superspecies, allospecies was proposed. [23]
Species aggregate
Used for a species complex, especially in plant taxa where polyploidy and apomixis are common. Historical synonyms are species collectiva  [ la ], introduced by Adolf Engler, conspecies, and grex. [24] Components of a species aggregate have been called segregates or microspecies. [24] Used as abbreviation agg. after the binomial species name. [8] [25]
Sensu lato
A Latin phrase meaning 'in the broad sense', it is often used after a binomial species name, often abbreviated as s.l., to indicate a species complex represented by that species. [26] [27] [28]

Identification

Distinguishing close species within a complex requires the study of often very small differences. Morphological differences may be minute and visible only by the use of adapted methods, such as microscopy. However, distinct species sometimes have no morphological differences. [19] In those cases, other characters, such as in the species' life history, behavior, physiology, and karyology, may be explored. For example, territorial songs are indicative of species in the treecreepers, a bird genus with few morphological differences. [29] Mating tests are common in some groups such as fungi to confirm the reproductive isolation of two species. [27]

Analysis of DNA sequences is becoming increasingly standard for species recognition and may, in many cases, be the only useful method. [19] Different methods are used to analyse such genetic data, such as molecular phylogenetics or DNA barcoding. Such methods have greatly contributed to the discovery of cryptic species, [19] [30] including such emblematic species as the fly agaric, [2] the water fleas, [31] or the African elephants. [3]

Salamandra atra-01-Kaernten-2008-Thomas Huntke.jpg
Salamandra atra
Salamandra corsica.jpg
Salamandra corsica
Salamandra salamandra (Marek Szczepanek).jpg
Salamandra salamandra
Similarity can be misleading: the Corsican fire salamander (center) was previously considered a subspecies of the fire salamander (right) but is in fact more closely related to the uniformly black Alpine salamander (left). [32]

Evolution and ecology

Speciation process

A species complex typically forms a monophyletic group that has diversified rather recently, as is shown by the short branches between the species A-E (blue box) in this phylogenetic tree. Phylogeny species complex.svg
A species complex typically forms a monophyletic group that has diversified rather recently, as is shown by the short branches between the species A–E (blue box) in this phylogenetic tree.

Species forming a complex have typically diverged very recently from each other, which sometimes allows the retracing of the process of speciation. Species with differentiated populations, such as ring species, are sometimes seen as an example of early, ongoing speciation: a species complex in formation. Nevertheless, similar but distinct species have sometimes been isolated for a long time without evolving differences, a phenomenon known as "morphological stasis". [19] For example, the Amazonian frog Pristimantis ockendeni is actually at least three different species that diverged over 5 million years ago. [33]

Stabilizing selection has been invoked as a force maintaining similarity in species complexes, especially when they adapted to special environments (such as a host in the case of symbionts or extreme environments). [19] This may constrain possible directions of evolution; in such cases, strongly divergent selection is not to be expected. [19] Also, asexual reproduction, such as through apomixis in plants, may separate lineages without producing a great degree of morphological differentiation.

Possible processes explaining similarity of species in a species complex: a - morphological stasis b - hybrid speciation Cryptic speciation.svg
Possible processes explaining similarity of species in a species complex:
a – morphological stasis
b – hybrid speciation

A species complex is usually a group that has one common ancestor (a monophyletic group), but closer examination can sometimes disprove that. For example, yellow-spotted "fire salamanders" in the genus Salamandra , formerly all classified as one species S. salamandra , are not monophyletic: the Corsican fire salamander's closest relative has been shown to be the entirely black Alpine salamander. [32] In such cases, similarity has arisen from convergent evolution.

Hybrid speciation can lead to unclear species boundaries through a process of reticulate evolution, in which species have two parent species as their most recent common ancestors. In such cases, the hybrid species may have intermediate characters, such as in Heliconius butterflies. [34] Hybrid speciation has been observed in various species complexes, such as insects, fungi, and plants. In plants, hybridization often takes place through polyploidization, and hybrid plant species are called nothospecies.

Range and habitats

Sources differ on whether or not members of a species group share a range. A source from Iowa State University Department of Agronomy states that members of a species group usually have partially overlapping ranges but do not interbreed with one another. [35] A Dictionary of Zoology (Oxford University Press 1999) describes a species group as complex of related species that exist allopatrically and explains that the "grouping can often be supported by experimental crosses in which only certain pairs of species will produce hybrids." [36] The examples given below may support both uses of the term "species group."

Often, such complexes do not become evident until a new species is introduced into the system, which breaks down existing species barriers. An example is the introduction of the Spanish slug in Northern Europe, where interbreeding with the local black slug and red slug, which were traditionally considered clearly separate species that did not interbreed, shows that they may be actually just subspecies of the same species. [37]

Where closely related species co-exist in sympatry, it is often a particular challenge to understand how the similar species persist without outcompeting each other. Niche partitioning is one mechanism invoked to explain that. Indeed, studies in some species complexes suggest that species divergence have gone in par with ecological differentiation, with species now preferring different microhabitats.[ citation needed ] Similar methods also found that the Amazonian frog Eleutherodactylus ockendeni is actually at least three different species that diverged over 5 million years ago. [33]

A species flock may arise when a species penetrates a new geographical area and diversifies to occupy a variety of ecological niches, a process known as adaptive radiation. The first species flock to be recognized as such was the 13 species of Darwin's finches on the Galápagos Islands described by Charles Darwin.

Practical implications

Biodiversity estimates

It has been suggested that cryptic species complexes are very common in the marine environment. [38] That suggestion came before the detailed analysis of many systems using DNA sequence data but has been proven to be correct. [39] The increased use of DNA sequence in the investigation of organismal diversity (also called phylogeography and DNA barcoding) has led to the discovery of a great many cryptic species complexes in all habitats. In the marine bryozoan Celleporella hyalina , [40] detailed morphological analyses and mating compatibility tests between the isolates identified by DNA sequence analysis were used to confirm that these groups consisted of more than 10 ecologically distinct species, which had been diverging for many millions of years.

Evidence from the identification of cryptic species has led some[ who? ] to conclude that current estimates of global species richness are too low.

Disease and pathogen control

The Anopheles gambiae mosquito complex contains both species that are a vector for malaria and species that are not. AnophelesGambiaemosquito.jpg
The Anopheles gambiae mosquito complex contains both species that are a vector for malaria and species that are not.

Pests, species that cause diseases and their vectors, have direct importance for humans. When they are found to be cryptic species complexes, the ecology and the virulence of each of these species need to be re-evaluated to devise appropriate control strategies.[ citation needed ] Examples are cryptic species in the malaria vector genus of mosquito, Anopheles , the fungi causing cryptococcosis, and sister species of Bactrocera tryoni, or the Queensland fruit fly. That pest is indistinguishable from two sister species except that B. tryoni inflicts widespread, devastating damage to Australian fruit crops, but the sister species do not. [42]

Conservation biology

When a species is found to be several phylogenetically distinct species, each typically has smaller distribution ranges and population sizes than had been reckoned. The different species can also differ in their ecology, such as by having different breeding strategies or habitat requirements, which must be taken into account for appropriate management.[ citation needed ] For example, giraffe populations and subspecies differ genetically to such an extent that they may be considered species. Although the giraffe, as a whole, is not considered to be threatened, if each cryptic species is considered separately, there is a much higher level of threat. [43]

See also

Related Research Articles

<i>Coregonus</i> Genus of fishes

Coregonus is a diverse genus of fish in the salmon family (Salmonidae). The Coregonus species are known as whitefishes. The genus contains at least 68 described extant taxa, but the true number of species is a matter of debate. The type species of the genus is Coregonus lavaretus.

The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleotide sequences for DNA, RNA, or amino acid sequences for proteins.

Phylogeography is the study of the historical processes that may be responsible for the past to present geographic distributions of genealogical lineages. This is accomplished by considering the geographic distribution of individuals in light of genetics, particularly population genetics.

Allopatric speciation – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.

<span class="mw-page-title-main">Evolutionary biology</span> Study of the processes that produced the diversity of life

Evolutionary biology is the subfield of biology that studies the evolutionary processes that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution holds that all species are related and gradually change over generations. In a population, the genetic variations affect the phenotypes of an organism. These changes in the phenotypes will be an advantage to some organisms, which will then be passed on to their offspring. Some examples of evolution in species over many generations are the peppered moth and flightless birds. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology.

<span class="mw-page-title-main">Sympatric speciation</span> Evolution of a new species from an ancestor in the same location

In evolutionary biology, sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap so that they occur together at least in some places. If these organisms are closely related, such a distribution may be the result of sympatric speciation. Etymologically, sympatry is derived from Greek συν (sun-) 'together' and πατρίς (patrís) 'fatherland'. The term was coined by Edward Bagnall Poulton in 1904, who explains the derivation.

<span class="mw-page-title-main">Peripatric speciation</span>

Peripatric speciation is a mode of speciation in which a new species is formed from an isolated peripheral population. Since peripatric speciation resembles allopatric speciation, in that populations are isolated and prevented from exchanging genes, it can often be difficult to distinguish between them., and peripatric speciation may be considered one type or model of allopatric speciation. The primary distinguishing characteristic of peripatric speciation is that one of the populations is much smaller than the other, as opposed to allopatric speciation, in which similarly-sized populations become separated. The terms peripatric and peripatry are often used in biogeography, referring to organisms whose ranges are closely adjacent but do not overlap, being separated where these organisms do not occur—for example on an oceanic island compared to the mainland. Such organisms are usually closely related ; their distribution being the result of peripatric speciation.

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<span class="mw-page-title-main">Molecular ecology</span> Subdiscipline of ecology

Molecular ecology is a subdiscipline of ecology that is concerned with applying molecular genetic techniques to ecological questions. It is virtually synonymous with the field of "Ecological Genetics" as pioneered by Theodosius Dobzhansky, E. B. Ford, Godfrey M. Hewitt, and others. Molecular ecology is related to the fields of population genetics and conservation genetics.

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<span class="mw-page-title-main">Plant evolution</span> Subset of evolutionary phenomena that concern plants

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A paraspecies is a species, living or fossil, that gave rise to one or more daughter species without itself becoming extinct. Geographically widespread species that have given rise to one or more daughter species as peripheral isolates without themselves becoming extinct are examples of paraspecies.

<span class="mw-page-title-main">Species</span> Basic unit of taxonomic classification, below genus

A species is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour, or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet. For example, Boa constrictor is one of the species of the genus Boa, with constrictor being the species' epithet.

<span class="mw-page-title-main">DNA barcoding</span> Method of species identification using a short section of DNA

DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections, an individual sequence can be used to uniquely identify an organism to species, just as a supermarket scanner uses the familiar black stripes of the UPC barcode to identify an item in its stock against its reference database. These "barcodes" are sometimes used in an effort to identify unknown species or parts of an organism, simply to catalog as many taxa as possible, or to compare with traditional taxonomy in an effort to determine species boundaries.

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Amy Reed McCune is an American ecologist and evolutionary biologist. She is a professor of ecology and evolutionary biology at Cornell University. McCune specializes in the history of life through the study of fishes. Her lab focuses on evolution with methodologies including paleobiology, phylogenetics, genetics and morphology.

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<span class="mw-page-title-main">Nonecological speciation</span>

When speciation is not driven by divergent natural selection, it can be said to be nonecological, so as to distinguish it from the typical definition of ecological speciation: "It is useful to consider ecological speciation as its own form of species formation because it focuses on an explicit mechanism of speciation: namely divergent natural selection. There are numerous ways other than via divergent natural selection in which populations might become genetically differentiated and reproductively isolated." It is likely that many instances of nonecological speciation are allopatric, especially when the organisms in question are poor dispersers, however sympatric nonecological speciation may also be possible, especially when accompanied by an "instant" loss of reproductive compatibility, as when polyploidization happens. Other potential mechanisms for nonecological speciation include mutation-order speciation and changes in chirality in gastropods.

Allochronic speciation is a form of speciation arising from reproductive isolation that occurs due to a change in breeding time that reduces or eliminates gene flow between two populations of a species. The term allochrony is used to describe the general ecological phenomenon of the differences in phenology that arise between two or more species—speciation caused by allochrony is effectively allochronic speciation.

In biology, parallel speciation is a type of speciation where there is repeated evolution of reproductively isolating traits via the same mechanisms occurring between separate yet closely related species inhabiting different environments. This leads to a circumstance where independently evolved lineages have developed reproductive isolation from their ancestral lineage, but not from other independent lineages that inhabit similar environments. In order for parallel speciation to be confirmed, there is a set of three requirements that has been established that must be met: there must be phylogenetic independence between the separate populations inhabiting similar environments to ensure that the traits responsible for reproductive isolation evolved separately, there must be reproductive isolation not only between the ancestral population and the descendent population, but also between descendent populations that inhabit dissimilar environments, and descendent populations that inhabit similar environments must not be reproductively isolated from one another. To determine if natural selection specifically is the cause of parallel speciation, a fourth requirement has been established that includes identifying and testing an adaptive mechanism, which eliminates the possibility of a genetic factor such as polyploidy being the responsible agent.

References

  1. ↑ Ron, Santiago; Caminer, Marcel (2014). "Systematics of treefrogs of the Hypsiboas calcaratus and Hypsiboas fasciatus species complex (Anura, Hylidae) with the description of four new species". ZooKeys (370): 1–68. Bibcode:2014ZooK..370....1C. doi: 10.3897/zookeys.370.6291 . ISSN   1313-2970. PMC   3904076 . PMID   24478591.
  2. 1 2 Geml J, Tulloss RE, Laursen GA, Sasanova NA, Taylor DL (2008). "Evidence for strong inter- and intracontinental phylogeographic structure in Amanita muscaria, a wind-dispersed ectomycorrhizal basidiomycete". Molecular Phylogenetics and Evolution. 48 (2): 694–701. Bibcode:2008MolPE..48..694G. doi:10.1016/j.ympev.2008.04.029. PMID   18547823. S2CID   619242.
  3. 1 2 Roca AL, Georgiadis N, Pecon-Slattery J, O'Brien SJ (2001). "Genetic evidence for two species of elephant in Africa". Science. 293 (5534): 1473–1477. Bibcode:2001Sci...293.1473R. doi:10.1126/science.1059936. PMID   11520983. S2CID   38285623.
  4. ↑ Moran P, Kornfield I (1993). "Retention of an Ancestral Polymorphism in the Mbuna Species Flock (Teleostei: Cichlidae) of Lake Malawi" (PDF). Molecular Biology and Evolution. 10 (5): 1015–1029.
  5. ↑ Brown JK, Frohlich DR, Rosell RC (1995). "The sweetpotato or silverleaf whiteflies: biotypes of Bemisia tabaci or a species complex?". Annual Review of Entomology. 40 (1): 511–534. doi:10.1146/annurev.en.40.010195.002455.
  6. ↑ De Queiroz, Kevin (2007). "Species Concepts and Species Delimitation". Systematic Biology. 56 (6): 879–886. doi: 10.1080/10635150701701083 . ISSN   1063-5157. PMID   18027281.
  7. 1 2 Mayr E. (1970). "Morphological species characters and sibling species". Populations, Species, and Evolution. Cambridge, MA: The Belknap Press of Harvard University Press. pp. 21–36. ISBN   978-0-674-69013-4.
  8. 1 2 Horandl, E.; Greilhuber, J.; Klimova, K.; Paun, O.; Temsch, E.; Emadzade, K.; Hodalova, I. (2009). "Reticulate evolution and taxonomic concepts in the Ranunculus auricomus complex (Ranunculaceae): insights from analysis of morphological, karyological and molecular data". Taxon. 58 (4): 1194–1215. doi:10.1002/tax.584012. PMC   2855680 . PMID   20401184.
  9. ↑ JONG, R. (December 1987). "Superspecies Pyrgus malvae (Lepidoptera: Hesperiidae) in the East Mediterranean, with notes on phylogenetic and biological relationships". Rijksmuseum van Natuurlijke Historie – Via Naturalis Repository.
  10. ↑ Moritz C, Schneider CJ, Wake DB (1992). "Evolutionary relationships within the Ensatina eschscholtzii complex confirm the ring species interpretation". Systematic Biology. 41 (3): 273–291. doi:10.1093/sysbio/41.3.273. S2CID   49267121.
  11. ↑ Bowen BW, Bass AL, Rocha LA, Grant WS, Roberston DR (2001). "Phylogeography of the trumpetfishes (Aulostomus): Ring species complex on a global scale". Evolution. 55 (5): 1029–1039. doi: 10.1111/j.0014-3820.2001.tb00619.x . PMID   11430639. S2CID   221735739.
  12. ↑ Muñoz MM; Crawford NG; McGreevy Jr. TJ; Messana NJ; Tarvin RD; Revell LJ; Zandvliet RM; Hopwood JM; Mock E; Schneider AL; Schneider CJ. (2013). "Divergence in coloration and ecological speciation in the Anolis marmoratus species complex" (PDF). Molecular Ecology. 22 (10): 2668–2682. Bibcode:2013MolEc..22.2668M. doi:10.1111/mec.12295. PMID   23611648. S2CID   16832446.
  13. ↑ Ride WD, Cogger HG, Dupuis C, Kraus O, Minelli A, Thompson FC, Tubbs PK, eds. (1999). "Chapter 9: Genus-group nominal taxa and their names". International Code of Zoological Nomenclature. London: The International Trust for Zoological Nomenclature. ISBN   978-0853010067.
  14. ↑ Lapage SP, Sneath PHA, Lessel EF, Skerman VBD, Seeliger HPR, Clark WA (1992). "Chapter 3. Rules of nomenclature with recommendations. Section 2. Ranks of taxa". In Lapage SP, Sneath PH, Lessel EF, Skerman VB, Seeliger HP, Clark WA (eds.). International Code of Nomenclature of Bacteria. Bacteriological Code, 1990 Revision. Washington (DC): ASM Press. ISBN   9781555810399. PMID   21089234.
  15. ↑ McNeill, J; et al., eds. (2012), International Code of Nomenclature for algae, fungi, and plants (Melbourne Code), adopted by the Eighteenth International Botanical Congress Melbourne, Australia, July 2011 (electronic ed.), Bratislava: International Association for Plant Taxonomy, retrieved 2012-12-20.
  16. ↑ Lawley, Jonathan W.; Gamero-Mora, Edgar; Maronna, Maximiliano M.; Chiaverano, Luciano M.; Stampar, Sérgio N.; Hopcroft, Russell R.; Collins, Allen G.; Morandini, André C. (2022-09-29). "Morphology is not always useful for diagnosis, and that's ok: Species hypotheses should not be bound to a class of data. Reply to Brown and Gibbons (S Afr J Sci. 2022;118(9/10), Art. #12590)". South African Journal of Science. 118 (9/10). doi: 10.17159/sajs.2022/14495 . ISSN   1996-7489.
  17. ↑ Mayr, Ernst (1942). Systematics and the Origin of Species, from the Viewpoint of a Zoologist. Harvard University Press. ISBN   9780674862500.
  18. ↑ Steyskal GC. (1972). "The meaning of the term 'sibling species'" (PDF). Systematic Zoology. 21 (4): 446. doi:10.1093/sysbio/21.4.446. Archived from the original (PDF) on 2015-02-07.
  19. 1 2 3 4 5 6 7 8 Bickford D, Lohman DJ, Sodhi NS, Ng PK, Meier R, Winker K, Ingram KK, Das I (2007). "Cryptic species as a window on diversity and conservation" (PDF). Trends in Ecology & Evolution. 22 (3): 148–155. Bibcode:2007TEcoE..22..148B. doi:10.1016/j.tree.2006.11.004. PMID   17129636.[ permanent dead link ]
  20. ↑ Hodges SA, Arnold ML (1994). "Columbines: a geographically widespread species flock" (PDF). Proceedings of the National Academy of Sciences of the United States of America. 91 (11): 5129–5132. Bibcode:1994PNAS...91.5129H. doi: 10.1073/pnas.91.11.5129 . PMC   43945 . PMID   8197196.
  21. ↑ Fontdevila A, Pla C, Hasson E, Wasserman M, Sanchez A, Naveira H, Ruiz A (1988). "Drosophila koepferae: a new member of the Drosophila serido (Diptera: Drosophilidae) superspecies taxon". Annals of the Entomological Society of America. 81 (3): 380–385. doi:10.1093/aesa/81.3.380.
  22. ↑ Wallis GP, Arntzen JW (1989). "Mitochondrial-DNA variation in the crested newt superspecies: Limited cytoplasmic gene flow among species". Evolution. 43 (1): 88–104. doi:10.2307/2409166. JSTOR   2409166. PMID   28568488.
  23. 1 2 Amadon D. (1966). "The superspecies concept". Systematic Biology. 15 (3): 245–249. doi:10.2307/sysbio/15.3.245.
  24. 1 2 Heywood VH. (1962). "The "species aggregate" in theory and practice". In VH Heywood; Löve Á. (eds.). Symposium on Biosystematics, organized by the International Organization of Biosystematists, Montreal, October 1962. pp. 26–36.
  25. ↑ Kankare M, Van Nouhuys S, Hanski I (2005). "Genetic divergence among host-specific cryptic species in Cotesia melitaearum aggregate (Hymenoptera: Braconidae), parasitoids of checkerspot butterflies". Annals of the Entomological Society of America. 98 (3): 382–394. doi:10.1603/0013-8746(2005)098[0382:GDAHCS]2.0.CO;2. S2CID   26360705.
  26. ↑ Wallis GP, Judge KF, Bland J, Waters JM, Berra TM (2001). "Genetic diversity in New Zealand Galaxias vulgaris sensu lato (Teleostei: Osmeriformes: Galaxiidae): a test of a biogeographic hypothesis". Journal of Biogeography. 28 (1): 59–67. Bibcode:2001JBiog..28...59W. doi:10.1046/j.1365-2699.2001.00535.x. S2CID   85946696.
  27. 1 2 Dai Y-C, Vainio EJ, Hantula J, Niemelä, Korhonen K (2003). "Investigations on Heterobasidion annosum s.lat. in central and eastern Asia with the aid of mating tests and DNA fingerprinting". Forest Pathology. 33 (5): 269–286. doi:10.1046/j.1439-0329.2003.00328.x.
  28. ↑ Van de Putte K, Nuytinck J, Stubbe D, Le HT, Verbeken A (2010). "Lactarius volemus sensu lato (Russulales) from northern Thailand: Morphological and phylogenetic species concepts explored". Fungal Diversity. 45 (1): 99–130. doi:10.1007/s13225-010-0070-0. S2CID   25615396.
  29. ↑ Tietze DT, Martens J, Sun YH (2006). "Molecular phylogeny of treecreepers (Certhia) detects hidden diversity". Ibis. 148 (3): 477–488. doi: 10.1111/j.1474-919X.2006.00547.x . Open Access logo PLoS transparent.svg
  30. ↑ Marques, Isabel; Montgomery, Sean A.; Barker, Michael S.; Macfarlane, Terry D.; Conran, John G.; Catalán, Pilar; Rieseberg, Loren H.; Rudall, Paula J.; Graham, Sean W. (2016-04-01). "Transcriptome-derived evidence supports recent polyploidization and a major phylogeographic division in Trithuria submersa (Hydatellaceae, Nymphaeales)". New Phytologist. 210 (1): 310–323. doi: 10.1111/nph.13755 . ISSN   1469-8137. PMID   26612464.
  31. ↑ Kotov, Alexey A.; Garibian, Petr G.; Bekker, Eugeniya I.; Taylor, Derek J.; Karabanov, Dmitry P. (2020-06-17). "A new species group from the Daphnia curvirostris species complex (Cladocera: Anomopoda) from the eastern Palaearctic: taxonomy, phylogeny and phylogeography". Zoological Journal of the Linnean Society . 191 (3): 772–822. doi:10.1093/zoolinnean/zlaa046. ISSN   0024-4082.
  32. 1 2 Steinfartz S, Veith M, Tautz D (2000). "Mitochondrial sequence analysis of Salamandra taxa suggests old splits of major lineages and postglacial recolonizations of Central Europe from distinct source populations of Salamandra salamandra". Molecular Ecology. 9 (4): 397–410. Bibcode:2000MolEc...9..397S. doi:10.1046/j.1365-294x.2000.00870.x. PMID   10736043. S2CID   10952136.
  33. 1 2 Elmer K, Davila J, Lougheed S (2007). "Cryptic diversity and deep divergence in an upper Amazonian leaflitter frog, Eleutherodactylus ockendeni". BMC Evolutionary Biology. 7 (1): 247. Bibcode:2007BMCEE...7..247E. doi: 10.1186/1471-2148-7-247 . ISSN   1471-2148. PMC   2254618 . PMID   18154647.
  34. ↑ Mallet J, Beltrán M, Neukirchen W, Linares M (2007). "Natural hybridization in heliconiine butterflies: the species boundary as a continuum". BMC Evolutionary Biology. 7 (1): 28. Bibcode:2007BMCEE...7...28M. doi: 10.1186/1471-2148-7-28 . PMC   1821009 . PMID   17319954. Open Access logo PLoS transparent.svg
  35. ↑ "Iowa State University Department of Agronomy". Archived from the original on 2011-10-05. Retrieved 2015-01-01.
  36. ↑ "Species Group | Encyclopedia.com". www.encyclopedia.com. Retrieved 18 October 2019.
  37. ↑ (in Danish) Engelke, S. (2006?): Til Snegleforeningen (Note to the Danish Slug-society). Article in Danish [ dead link ]
  38. ↑ Knowlton N (1993). "Sibling species in the sea". Annual Review of Ecology and Systematics. 24 (1): 189–216. doi:10.1146/annurev.es.24.110193.001201. ISSN   0066-4162.
  39. ↑ Knowlton N. (February 2000). "Molecular genetic analyses of species boundaries in the sea". Hydrobiologia. 420 (1): 73–90. Bibcode:2000HyBio.420...73K. doi:10.1023/A:1003933603879. ISSN   0018-8158. S2CID   40909997.
  40. ↑ Gómez A, Wright PJ, Lunt DH, Cancino JM, Carvalho GR, Hughes RN (2007). "Mating trials validate the use of DNA barcoding to reveal cryptic speciation of a marine bryozoan taxon". Proceedings of the Royal Society B. 274 (1607): 199–207. doi:10.1098/rspb.2006.3718. ISSN   0962-8452. PMC   1685843 . PMID   17035167.
  41. ↑ Besansky NJ, Powell JR, Caccone A, Hamm DM, Scott JA, Collins FH (1994). "Molecular phylogeny of the Anopheles gambiae complex suggests genetic introgression between principal malaria vectors". Proceedings of the National Academy of Sciences of the United States of America. 91 (15): 6885–8. Bibcode:1994PNAS...91.6885B. doi: 10.1073/pnas.91.15.6885 . PMC   44302 . PMID   8041714.
  42. ↑ Clarke, A.R.; Powell, K.S.; Weldon, C.W.; Taylor, P.W. (2010-11-02). "The ecology of Bactrocera tryoni (Diptera: Tephritidae): what do we know to assist pest management?" (PDF). Annals of Applied Biology. 158 (1): 26–54. doi:10.1111/j.1744-7348.2010.00448.x. hdl: 10019.1/122744 . ISSN   0003-4746.
  43. ↑ Brown D, Brenneman R, Koepfli KP, Pollinger J, Mila B, Georgiadis N, Louis E, Grether G, Jacobs D, Wayne R (2007). "Extensive population genetic structure in the giraffe". BMC Biology. 5 (1): 57. doi: 10.1186/1741-7007-5-57 . ISSN   1741-7007. PMC   2254591 . PMID   18154651.
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