Species

Character State ◽

Units Of Analysis ◽

Perceived Reality

This chapter studies the systematists' perspective on species concepts and the role of species in systematics. No matter how sophisticated the tools and methods enhancing the conceptualization of reality may become in the future, systematists will still be constrained by their perceptions. In their more modest, empirical view, systematists embrace their perceived reality and prefer species concepts that incorporate tools for identifying and delimiting species as empirical hypotheses, thereby providing them with efficacious working terminal elements for phylogenetic analysis and classification of more inclusive taxa. It is fortunate that cladists employed the notion of a “phylogenetic” species concept based on diagnosability before more metaphysically inclined authors appropriated the term for concepts founded on monophyly or common ancestors. As noted, Willi Hennig's species concept was a version of the “biological” species concept, and it fell to his followers to develop a species concept that is well suited to cladistic principles. Among the earliest of the post-Hennigian empiricists was American Museum ichthyologist Donn Rosen. Rosen's concept, sometimes called the apomorphic concept because of its requirement that every recognized species must have its own derived character state, accomplished two key advances for systematics: it proposed a cladistic criterion for recognizing species, and it defined species as the minimal units of analysis, as far as taxonomy is concerned, thus setting a lower bound for systematic inquiry.

Species limits in Pteruthius (Aves: Corvida) shrike-babblers: a comparison between the Biological and Phylogenetic Species Concepts

Zootaxa ◽

10.11646/zootaxa.2301.1.2 ◽

2009 ◽

Vol 2301 (1) ◽

pp. 29-54 ◽

Cited By ~ 4

Author(s):

FRANK E. RHEINDT ◽

JAMES A. EATON

Keyword(s):

Species Concept ◽

Molecular Data ◽

Biological Species ◽

Species Concepts ◽

Phylogenetic Species ◽

Species Status ◽

Sampling Regime ◽

Morphological And Molecular Data

The question of how to define a species continues to divide biologists. Meanwhile, the application of different species concepts has led to disparate taxonomic treatments that confound conservationists and other biologists. The most widely followed guidelines to species designation in avian and other vertebrate taxonomy are Ernst Mayr’s Biological Species Concept (BSC) and Joel Cracraft’s version of the Phylogenetic Species Concept (PSC). Although the BSC is considered to be more conservative in its assignment of species status, there is a lack of research demonstrating differences in taxonomic treatment between the BSC and the PSC with reference to a multi-taxon multi-trait study system. We examined the case of five traditionally recognized species of shrike-babbler (Pteruthius) that have recently been divided into 19 species under the PSC. Re-analyzing previous morphological and molecular data and adding new vocal data, we propose a BSC classification of 9 species. However, taking into consideration geographic gaps in the sampling regime, we contend that additional data will likely reduce discrepancies between the total numbers of species designated under the PSC and BSC. The current PSC species total is a likely overestimate owing to species diagnosis based on characters that erroneously appear to be unique to a taxon at low sample size. The current BSC species total as here proposed is a likely underestimate on account of the conservative designation of taxa as subspecies in equivocal cases, e.g. where BSC species status is potentially warranted but may be masked by insufficient data.

An alternative species taxonomy of the birds of Mexico

Biota Neotropica ◽

10.1590/s1676-06032004000200013 ◽

2004 ◽

Vol 4 (2) ◽

pp. 1-32 ◽

Cited By ~ 55

Author(s):

Adolfo G. Navarro-Sigüenza ◽

A. Townsend Peterson

Keyword(s):

Species Concept ◽

Bird Species ◽

Biological Species ◽

Species Concepts ◽

Phylogenetic Species ◽

Alternative Species ◽

Species Taxonomy

Extensive debate has surrounded the application of alternative species concepts in Ornithology. The biological species concept (BSC) and phylogenetic species concept (PSC) have typically been set in opposition, with extensive debate on the relative merits of each. An alternative is the evolutionary species concept (ESC), which offers a perspective similar to that of the PSC, yet with several significant differences. To date, no major avifauna has been examined and compared among taxonomic viewpoints. Herein, we develop an alternative phylogenetic/evolutionary species taxonomy to the current BSC treatment for the more than 1000 bird species of Mexico. A total of 135 biological species was divided to produce a total of 323 phylogenetic/evolutionary species, 122 of which represent “new” endemic forms in Mexico.

Discriminating arboviral species

Journal of General Virology ◽

10.1099/jgv.0.001572 ◽

2021 ◽

Vol 102 (4) ◽

Author(s):

Yiyuan Li ◽

Angela C. O’Donnell ◽

Howard Ochman

Keyword(s):

Evolutionary History ◽

Viral Vectors ◽

Species Concept ◽

International Committee ◽

Biological Species ◽

Substantial Variation ◽

Artificial Boundaries ◽

Human Infections

Mosquito-borne arboviruses, including a diverse array of alphaviruses and flaviviruses, lead to hundreds of millions of human infections each year. Current methods for species-level classification of arboviruses adhere to guidelines prescribed by the International Committee on Taxonomy of Viruses (ICTV), and generally apply a polyphasic approach that might include information about viral vectors, hosts, geographical distribution, antigenicity, levels of DNA similarity, disease association and/or ecological characteristics. However, there is substantial variation in the criteria used to define viral species, which can lead to the establishment of artificial boundaries between species and inconsistencies when inferring their relatedness, variation and evolutionary history. In this study, we apply a single, uniform principle – that underlying the Biological Species Concept (BSC) – to define biological species of arboviruses based on recombination between genomes. Given that few recombination events have been documented in arboviruses, we investigate the incidence of recombination within and among major arboviral groups using an approach based on the ratio of homoplastic sites (recombinant alleles) to non-homoplastic sites (vertically transmitted alleles). This approach supports many ICTV-designations but also recognizes several cases in which a named species comprises multiple biological species. These findings demonstrate that this metric may be applied to all lifeforms, including viruses, and lead to more consistent and accurate delineation of viral species.

The increasing multiplicity of the species concepts

BSGF - Earth Sciences Bulletin ◽

10.2113/176.2.221 ◽

2005 ◽

Vol 176 (2) ◽

pp. 221-225

Author(s):

Jean Génermont

Keyword(s):

Species Concept ◽

Cladistic Analysis ◽

Biological Species ◽

Point Of View ◽

Phylogenetic Species ◽

Ecological Criteria ◽

Stem Species ◽

Definition Of

Abstract In 1980, Henri Tintant advocated the usefulness of the biological species concept in paleontology. At this time, this concept was still accepted by many neontologists, but it was already rather severely criticized by some others. In fact, a lot of new concepts appeared in the course of the following two decades. While a few ones are mere adjustments of the biological concept, for instance taking in account ecological criteria, in such a way that it could be applied to clonal organisms, some others, which were developed in connexion with the cladistic theory of taxonomy, are truly new from a conceptual point of view. The diagnosable version of the phylogenetic species concept is somewhat reminiscent of Simpson’s evolutionary species concept, since it accepts phyletic speciation as well as survival of the stem species after a cladogenetic event. One of its more criticizable features, from a cladistic point of view, is that the species are not necessarilly monophyletic. On another hand, according to the monophyly version of the phylogenetic species concept, species are recognized rather subjectively as monophyletic taxa revealed by some previous cladistic analysis dealing with operational taxonomic units. A consensus on the definition of species cannot be expected, since all concepts related to the biological one are founded on population grouping on the basis of potentially identical evolutionary fates, while those which are related to cladistic taxonomy are exclusively concerned with historical features.

Predictors of Taxonomic Inflation and its Role in Primate Conservation

10.1101/2021.09.10.459781 ◽

2021 ◽

Author(s):

Maria J.A. Creighton ◽

Alice Q. Luo ◽

Simon M. Reader ◽

Arne Ø. Mooers

Keyword(s):

Perceived Risk ◽

Species Concept ◽

Research Effort ◽

Biological Species ◽

Primate Species ◽

Primate Conservation ◽

Initial Application ◽

Positive Message

ABSTRACTSpecies are the main unit used to measure biodiversity, but different preferred diagnostic criteria can lead to very different delineations. For instance, named primate species have more than doubled since 1982. Such increases have been termed “taxonomic inflation” and have been attributed to the widespread adoption of the ‘phylogenetic species concept’ (PSC) in preference to the previously popular ‘biological species concept’ (BSC). Criticisms of the PSC have suggested taxonomic inflation may be biased toward particular taxa and have unfavourable consequences for conservation. Here, we explore predictors of taxonomic inflation across primate taxa since the initial application of the PSC nearly 40 years ago. We do not find evidence that diversification rate, the rate of lineage formation over evolutionary time, is linked to inflation, contrary to expectations if the PSC identifies incipient species. We also do not find evidence of research effort in fields where work has been suggested to motivate splitting being associated with increases in species numbers among genera. To test the suggestion that splitting groups is likely to increase their perceived risk of extinction, we test whether genera that have undergone more splitting have also observed a greater increase in their proportion of threatened species since the introduction of the PSC. We find no cohesive signal of inflation leading to higher threat probabilities across primate genera. Overall, this analysis sends a positive message that threat statuses of primate species are not being overwhelmingly affected by splitting in line with what has recently been reported for birds. Regardless, we echo warnings that it is unwise for conservation to be reliant on taxonomic stability. Species (however defined) are not independent from one another, thus, monitoring and managing them as such may not meet the overarching goal of conserving biodiversity.

Geographic Variation in the Wingtip Patterns of Black-Legged Kittiwakes

The Condor ◽

10.1093/condor/104.3.687 ◽

2002 ◽

Vol 104 (3) ◽

pp. 687-693

Author(s):

John W. Chardine

Keyword(s):

Geographic Variation ◽

Barents Sea ◽

Species Concept ◽

Biological Species ◽

Genotypic Differences ◽

Rissa Tridactyla ◽

The Pacific ◽

Circumpolar Arctic

Abstract This paper reports geographic variation in wingtip patterns of Black-legged Kittiwakes (Rissa tridactyla) from the circumpolar Arctic. The amount of black in the wingtip increased and the amount of white decreased from Arctic Canada–west Greenland, counterclockwise to the Pacific. Differences were greatest between Pacific and Atlantic, but were also apparent within the Atlantic sample. Patterns of variation were not clinal. Known levels of philopatry in kittiwakes would tend to maintain both phenotypic and genotypic differences between regions, but the similarity of birds from Newfoundland, British Isles, and Barents Sea suggests some degree of dispersal over this wide area. Wingtip pattern data support continued separation of Pacific and Atlantic kittiwakes into two subspecies under the biological species concept. Under the phylogenetic species concept, Pacific and Atlantic Black-legged Kittiwakes may represent two species. Variación Geográfica en los Patrones de Coloración de la Punta del Ala de Rissa tridactyla Resumen. Este trabajo presenta la variación geográfica existente en los patrones de coloración de la punta del ala de Rissa tridactyla en el área circumpolar ártica. La cantidad de negro en la punta del ala incrementó y la cantidad de blanco disminuyó desde el ártico canadiense y el oeste de Groenlandia en sentido contrario a las agujas del reloj hacia el Pacífico. Las mayores diferencias se registraron entre el Pacífico y el Atlántico, pero también fueron evidentes en la muestra del Atlántico. Los patrones de variación no fueron graduales. Los niveles conocidos de filopatría en R. tridactyla tenderían a mantener las diferencias tanto fenotípicas como genotípicas entre regiones, pero la similitud de las aves de Newfoundland, las Islas Británicas y el Mar de Barents sugiere algún grado de dispersión a través de esta extensa área. Considerando el concepto biológico de especie, los datos sobre los patrones de la punta del ala apoyan la separación de las aves del Pacífico y del Atlántico en dos subespecies. Considerando el concepto filogenético de especie, los individuos de R. tridactyla del Pacífico y del Atlántico pueden pertenecer a dos especies diferentes.

A revision of the Trimeresurus puniceus-complex (Serpentes: Viperidae: Crotalinae) based on morphological and molecular data

Zootaxa ◽

10.11646/zootaxa.1293.1.1 ◽

2006 ◽

Vol 1293 (1) ◽

pp. 1 ◽

Cited By ~ 2

Author(s):

PATRICK DAVID ◽

GERNOT VOGEL ◽

S. P. VIJAYAKUMAR ◽

NICOLAS VIDAL

Keyword(s):

Species Concept ◽

Distinct Species ◽

Morphological Characters ◽

Molecular Data ◽

Biological Species ◽

Valid Species ◽

Morphological And Molecular Data ◽

A New Species

The brown Asian pitvipers of the genus Trimeresurus related to Trimeresurus puniceus (informal Trimeresurus puniceus-complex) are revised on the basis of morphological and molecular analyses. Variation in morphological characters were investigated among 119 specimens from 62 populations of the whole range of the pitvipers currently known as Trimeresurus puniceus (Boie, 1827), Trimeresurus borneensis (Peters, 1872) and Trimeresurus brongersmai Hoge, 1969. Molecular and morphological analyses clearly differentiate two groups of taxa, referrable to the informal Trimeresurus puniceus-group and Trimeresurus borneensis-group, and confirm the distinct specific status of T. puniceus and T. borneensis. Morphological univariate and multivariate analyses differentiate six clusters of populations that are morphologically diagnosable, of which five are here considered to represent independent lineages and one is placed incertae sedis pending the availability of further specimens. These clusters are considered to be distinct species following the Biological Species Concept and the Phylogenetic Species Concept. One of them is described as a new species, Trimeresurus andalasensis spec. nov. (T. borneensis-group), which includes populations from northern Sumatra. Trimeresurus wiroti Trutnau, 1981 is revalidated to accommodate populations from Thailand and West Malaysia. Trimeresurus borneensis is here considered endemic to Borneo. Trimeresurus puniceus is known from Java and from South Sumatra, but the taxonomy of this species in Sumatra is left unresolved. Also left unresolved is the taxonomic position of specimens from western Sumatra and the Mentawai Archipelago, and from the Natuna Islands and Anamba Islands. Although belonging to the T. puniceus-group, they show some differences to other specimens of the group. They are not referred to any taxon pending the collection of additional specimens. Lastly, Trimeresurus brongersmai is confirmed as a valid species from the Mentawai Archipelago. A key to these taxa is provided.

Is the taxonomy appropriate? Delineating species for conservation purposes

10.1093/oso/9780198783398.003.0009 ◽

2017 ◽

Author(s):

Richard Frankham ◽

Jonathan D. Ballou ◽

Katherine Ralls ◽

Mark D. B. Eldridge ◽

Michele R. Dudash ◽

...

Keyword(s):

Species Concept ◽

Conservation Management ◽

Biological Species ◽

Species Concepts ◽

Outbreeding Depression ◽

Genetic Rescue ◽

Low Genetic Diversity ◽

Inbred Populations ◽

Species Definitions

The first step in conservation management is to delineate groups for separate versus combined management. However, there are many problems with species delineation, including diverse species definitions, lack of standardized protocols, and poor repeatability of delineations. Definitions that are too broad will lead to outbreeding depression if populations are crossed, while those that split excessively may preclude genetic rescue of small inbred populations with low genetic diversity. To minimize these problems, we recommend the use of species concepts based upon reproductive isolation (such as the biological species concept) and advise against the use of phylogenetic and general lineage species concepts. We provide guidelines as to when taxonomy requires revision and outline protocols for robust species delineations.

Conservation and species lists: taxonomic neglect promotes the extinction of endemic birds, as exemplified by taxa from eastern Atlantic islands

Bird Conservation International ◽

10.1017/s0959270900003063 ◽

1996 ◽

Vol 6 (2) ◽

pp. 181-196 ◽

Cited By ~ 36

Author(s):

C. J. Hazevoet

Keyword(s):

Species Concept ◽

Conservation Status ◽

Morphological Differentiation ◽

Taxonomic Status ◽

Biological Species ◽

Hierarchical Level ◽

Conservation Priorities ◽

Clinal Variation ◽

Phylogenetic Species Concept

SummaryWhen formulating conservation priorities, conservation biologists often rely on published lists of species-level taxa. This paper discusses the nature and taxonomic status of “species” and “subspecies” and different ways of defining “species”. Species are here taken to be terminal and evolutionarily independent units which are qualitatively diagnosable and reproductively cohesive; genealogical biodiversity is thus taken for what it is in the first place, namely the observable result of evolutionary history, an approach which has become known as the phylogenetic species concept (PSC). In contrast to the widely applied Mayrian or “biological” species concept (BSC), no inferences are made about how the degree of morphological differentiation of allopatric but seemingly closely related taxa translates in the absence or presence of reproductive isolation. Many diagnosably distinct endemic island taxa have traditionally been treated as “subspecies” of widespread “polytypic biological” species. At the same time, the “subspecies” category is also used to name arbitrarily delimited sections of intraspecific clinal variation. Thus, the “subspecies” category subjects entirely different evolutionary phenomena to the same hierarchical level through the use of trinomials. Nevertheless, and despite the discrepancy in ontological status among its contents, “subspecies” are usually considered to be of lower evolutionary and/or conservation status than “species” and this has resulted in low conservation priorities allotted to diagnosably distinct island endemics, many of which have traditionally been considered to be “merely Mayrian subspecies”. This has been recognized by some authorities who, because of the threatened status of certain island taxa, advocated treating them binomially in order to generate appropriate conservation measures to save them from extinction, without however justifying their action by any sort of phylogenetic reasoning. Although well intended and sometimes quite successful as regards the follow-up by conservationists, this demonstrates the arbitrary manner in which “species” can be defined under the BSC. Some examples of endemic taxa from eastern Atlantic islands are discussed, demonstrating the way “list thinking” and the lack of phylogenetic reasoning among conservationists translates into the presence or absence of conservation actions. Some of the criticisms of the PSC by adherents of the BSC are discussed. It is advocated that conservationists replace “list thinking” with “lineage thinking”.

Zoogeography of primates in insular Southeast Asia: species-area relationships and the effects of taxonomy

Contributions to Zoology ◽

10.1163/18759866-07702008 ◽

2008 ◽

Vol 77 (2) ◽

pp. 117-126 ◽

Cited By ~ 12

Author(s):

Vincent Nijman ◽

Erik Meijaard

Keyword(s):

Species Richness ◽

Southeast Asia ◽

Species Concept ◽

Biological Species ◽

Primate Species ◽

Species Number ◽

Extant Species ◽

Species Area

Given its complex zoogeography and large number of islands insular Southeast Asia makes an excellent subject for studying the interrelationships of species richness, island area and isolation. The islands are merely highpoints of an immense shallow continental shelf which during Pleistocene glacial periods was exposed periodically as dry land connecting the now isolated islands with one another. The area is home to a large number of primate taxa, including many endemic to the region (Nasalis, Presbytis, Pongo, Symphalangus, Simias, Tarsius). Worldwide, the number of described (extant) species of primates has doubled in the last two decades partially as a result of applying a different species concept (viz. Phylogenetic Species Concept PSC as opposed to the Biological Species Concept BSC). According to Isaac et al. (Trends in Ecology and Evolution 19: 464-469, 2004) this ‘taxonomic inflation’ will influence the outcome of macroecological studies. We studied the species-area relationships in Primates on 118 islands in insular Southeast Asia, and used two taxonomies (PSC and BSC). The number of primate species (PSC 37 species, BSC 23 species) is highly significantly related to surface area of the islands, and the slope of the curve is similar for both PSC and BSC species (z = 0.13). Species ‘newly’ described under the PSC are not only from large islands but also smaller ones hence affecting neither intercept nor the slope of the curve. Area alone was a much better predictor for primate species richness than models that included other macroecological variables (latitude, longitude, altitude, distance to mainland, greatest depth between island and mainland, distance to neighbouring islands). Degree of isolation has little influence on species number but both longitude and latitude are inversely correlated with the number of species per island, suggesting that species numbers decrease in a northerly and easterly direction. The low z-values suggest that for primates the islands of Southeast Asia are perhaps less isolated than previously recognised.