Modern Species Concepts Research Articles

Towards elucidating species diversity of European inlandStrigamia(Chilopoda: Geophilomorpha): a first reassessment integrating multiple lines of evidence

AbstractStrigamia centipedes are widespread in European forest soils. However, a complex and inconsistent taxonomy has developed over time. Based on a modern species concept, we evaluated multiple lines of evidence for speciation among inland populations of Strigamia from the Italian region to the Baltic region, across central Europe. Hypotheses of species delimitation were drawn independently from: (1) morphological differentiation, by means of model-based cluster analyses of 52 specimens, after controlling for allometry and sexual dimorphism; (2) syntopy of morphologically distinct individuals, assumed to be representatives of coexistent species, from > 700 sites; and (3) molecular differentiation, by various methods applied to cytochrome c subunit I sequences of the same 52 specimens. Diagnoses and geographical distributions were revised by re-examining > 2000 specimens and the entire literature. We found preliminary evidence for: a Strigamia acuminata species complex, widespread, including a candidate species from the Eastern Alps differing in the forcipules; a Strigamia carniolensis species complex, hitherto often called Strigamia crassipes, widespread south of the Alps but absent from Sicily; a Strigamia crassipes species complex, hitherto often called Strigamia transsilvanica, more widespread than previously known, including three candidate species co-occurring in the Western Alps and differing in body size and the number of legs despite little genetic divergence; and Strigamia engadina, exclusive to a narrow part of the Central Alps.

Studies in the vascular flora of the southeastern United States. VI

As part of ongoing efforts to understand, document, and conserve the flora of southeastern North America, we propose a number of taxonomic changes, nomenclatural changes, interpretations of nativity, and distributional accounts. Regarding the Asaroideae (Aristolochiaceae), we support continued recognition of Hexastylis (and other segregates of a very broad Asarum s.l.) at generic rank and make the necessary combinations to continue the use of Hexastylis in southeastern North America floras. In Conoclinium (Asteraceae), we present morphological and distributional evidence corroborating the recent suggestion (based on molecular evidence) that Chapman’s 1878 C. dichotomum is distinct, warrants recognition, and is present as a second Conoclinium in the southeastern North American flora. An analysis of historical accounts of Gaillardia pulchella (Asteraceae) strongly suggests that its modern occurrence east of Texas is adventive, rather than native. Two rare southeastern United States skullcaps, Scutellaria mellichampii and S. ocmulgee (Lamiaceae), have been persistently confused with one another and other species; we present a reassessment of the taxonomic distinction between them, best ways to distinguish them and similar species, and their known distributions. A reassessment of the taxonomy, distribution, and ecology of Linum carteri (Linaceae), a rare southern Florida endemic, confirms that two species should be recognized by modern species concepts; we make the necessary new combination to effect the recognition of two narrowly endemic species. In Andropogon (Poaceae), we propose that A. virginicus var. decipiens warrants recognition as distinct at species rank from other entities in the Andropogon virginicus complex. We also present more comprehensive information on the distributions of four species of “bushy bluestems” (Andropogon glomeratus s.l.), their ecology, and their practical recognition. In the Violaceae, modern reassessment of the taxonomy of many species (especially in the genus Viola) by H.E. Ballard, Jr. and collaborators have been vexed by uncertain application of many “old” names; we here provide a first installment of typifications and nomenclatural interpretations needed to move forward with a modern treatment of the genus in our region. In Xyris (Xyridaceae), we re-establish the generally ignored X. elliottii var. stenotera based on careful and extensive study of its morphology and ecology in comparison to X. elliottii var. elliottii, including a transplant study. English naturalist Mark Catesby (1683–1749) has been honored by having a genus and fifteen species of plants named for him, but most of these honorific names have been constructed in manners contrary to the Shenzhen Code; as these are “errors to be corrected,” we therefore propose to correct and standardize these honorifics by restoring his name ‘catesby-‘ as the root of the names. Similarly, in seven names (variably formed) employed by W.W Ashe to honor his cousin and (later) wife Margaret Haywood Henry (Wilcox) (Ashe), we also standardize and correct the root of the names to be accurately based on her name, ‘margaret-,’ in conformance with the Shenzhen Code.

Species Thinking: Animals, Women, and Literary Tropes in Mary Wollstonecraft's A Vindication of the Rights of Woman

This essay examines how Mary Wollstonecraft’s A Vindication of the Rights of Woman charts women’s vexed relationships to the conceptual categories of the human and the animal in eighteenth-century writing. It argues that Wollstonecraft’s tactical use of animal metaphors should be understood in the context of “species thinking,” a mode of thinking that starkly differentiates humans from other animals in order to champion the soul, reason, and language as quintessentially human faculties. The analysis foregrounds how—as Wollstonecraft draws from the modern species concept in order to make a progressive argument about gender equality—she relegates animals to an inferior moral status.

Anther smuts of Silene acaulis and S. uniflora in the Outer Hebrides, including an assessment of ITS genotypes of Microbotryum silenes-acaulis

Anther smuts on Silene acaulis and S. uniflora from the Outer Hebrides, Scotland, UK), are analysed using morphological and molecular techniques, and found to represent Microbotryum silenes-acaulis and M. silenes-inflatae, respectively. This is the frst identifcation of caryophyllaceous anther smuts in the Outer Hebrides according to modern species concepts and the frst report of Microbotryum silenes-acaulis confrmed by molecular analysis from the British Isles. Additionally, the genetic structure of Microbotryum silenes- acaulis, based on all currently available ITS sequences, is analysed and discussed. Seven ITS genotypes are determined for Microbotryum silenes-acaulis, including three genotypes in North America and four genotypes in Europe. Compared to European accessions, all North American accessions share specifc nucleotides and are genetically divergent.

Rubus gizellae (Rosaceae), a bramble species from southeastern Europe—identification history, neotypification, and taxonomic notes

The genus Rubus Linnaeus (1753: 492) with nearly 700 species in Europe (Kurtto et al. 2010) constitutes an extraordinarily taxonomically critical group within the Rosaceae (Rosoideae). The richness of morphotypes combined with a poor understanding of the breeding system of apomictic brambles has resulted in the description of thousands of entities. Lack of taxonomic standards and an overwhelming number of scientific names has caused nomenclatorial chaos, which mainly has been resolved by the modern species concept developed in Europe in the late 1900s (“Weberian reform”, Weber 1999; Haveman & de Ronde 2012). However, the review of older names is an extended process and re-evaluation of names has often failed due to lack of type material.

Island evolution and systematic revision of Comoran snakes: why and when subspecies still make sense.

Species delimitation and species concepts have been a matter of debate among biodiversity researchers in the last decades, resulting in integrative taxonomy approaches and the use of modern species concepts, such as the phylogenetic, evolutionary or general lineage species concepts. The discussion of subspecies status and concepts has been addressed much less extensively, with some researchers completely refraining from recognizing subspecies. However, allopatric insular populations that are particularly differentiated have traditionally been assigned subspecies status. We studied the molecular phylogeny and morphology of endemic Comoran tree snakes of the genus Lycodryas. Taking an integrative taxonomic approach, we used the concept of independent lines of evidence to discriminate between evidence for specific and subspecific status. Molecular (mtDNA) and morphological data provided sufficient evidence to support four different taxa within Comoran Lycodryas. In a revision of this group, we propose two species, each with two subspecies. We present a discussion of the strong sexual dichromatism unique to Comoran Lycodryas within the genus and related genera that may be explained by sexual selection in combination with the absence of major predators. Then, we discuss the effects of insular evolution and the “island rule” on morphological traits in Comoran Lycodryas and in Liophidium mayottensis, another snake endemic to the Comoros. The absence of larger-bodied snakes may have promoted an increase in body size and the number of dorsal scale rows in these species. Finally, we discuss the subspecies concept, its applications and its significance for integrative taxonomy and for limiting taxonomic inflation. We emphasize that taxon descriptions should be based on an integrative approach using several lines of evidence, preferably in combination with statements on the underlying species concepts or operational criteria, to increase the objectivity and comparability of descriptions.

On the integrated frameworks of species concepts: Mayden’s hierarchy of species concepts and de Queiroz’s unified concept of species

Richard L. Mayden and Kevin de Queiroz have devised and developed a hierarchy of species concepts and a unified species concept, respectively. Although their integrated frameworks of species concepts are rather different as to how to integrate the diverse modern concepts of species, the end result is that they are likely to agree on species recognition in nature, because they virtually share the same major components (i.e. evolutionary or lineage concept of species; same way of delimiting species), and have the same important consequences. Both the hierarchical and unified frameworks, however, are interpreted to have shortcoming regarding the way of integrating the modern species concepts. I reformulate these ideas into a framework of species concepts as follows: It treats the idea of species as population-level evolutionary lineages (sensu Wiley 1978) as the concept for species category, and it adopts the contingent biological properties of species (e.g. internal reproductive isolation, diagnosability, monophyly) as operational criteria in delimiting species. I also suggest that existing and revised versions of the integrated framework of species concepts all are not new species concepts, but versions of the evolutionary species concept, because they treat the evolutionary (or lineage) species concept as the concept for species category.

Biometric methods for species recognition in Trigonia Bruguière (Bivalvia; Trigoniidae): a case study from the Upper Jurassic of Western Europe

From its first occurrence in the Middle Triassic to the Late Cretaceous, and thus for almost 200 Ma, Trigonia, type genus of the family Trigoniidae, has been a common constituent of global shallow-marine benthic faunas. The genus is highly over-split at the species level, which hampers sound biostratigraphic, palaeobiogeographic, and palaeoecologic applications. The present study focuses on two closely related species, i.e. Trigonia reticulata Agassiz and Trigonia pseudomeriani Choffat, and illustrates typical problems of species identification in Trigonia. T. reticulata is a well-known representative of the genus with a significant fossil record in Lower Oxfordian to Upper Kimmeridgian strata of western and central Europe, and likely is the ancestor of T. pseudomeriani, which is endemic to the Upper Oxfordian to Lower Kimmeridgian Alcobaca formation of the Lusitanian Basin (central Portugal). In order to effectively display intraspecific variability, digital analyses of a set of metric and non-metric parameters, including outline analysis, were applied to a representative number of specimens from different localities and stages. Originally, these methods were intended to show that both forms are conspecific. Instead, the analysis supports the distinctness of both species based on a very limited number of non-plastic characters. The methods applied can be transferred to other species in Trigonia and may lead to a modern species concept for the genus. Also, they may be successfully applied to other members of the Trigoniinae.

Identities of Tenebrio Linnaeus types at Uppsala, and the resulting changes in old darkling beetle names (Insecta: Coleoptera: Tenebrionidae)

In this paper, five names used for darkling beetles (Insecta: Coleoptera: Tenebrionidae) in the Linnaeus collection at the Museum of Zoology, Uppsala University (UUMZ) are evaluated based on specimen examinations, modern species concepts, and review of the original species diagnoses. The types are of species described in Systema Naturae (Tenebrio caraboides L., 1758, Tenebrio gibbus L., 1760, Tenebrio gigas L., 1767, and Tenebrio muricatus L., 1758) and Museum Ludovicae Ulrica (Tenebrio spinosus L., 1764). Tenebrio caraboides L., 1758, refers to a composite type series consisting of two UUMZ paralectotypes, identified herein as Pachychila hispanica Solier, 1835, and gaditana Rosenhauer, 1856, and the lectotype in the Linnean Collection, Natural History Museum, London (BMNH), for the ground beetle Cychrus caraboides (L. 1758). The three specimens in the De Geer Collection, Swedish Museum of Natural History, Stockholm (NHRS), under Tenebrio gibbus L., 1760, are determined as Psammodes gibbus (L., 1760), comb. nov.; this includes the “lost” type of Linnaeus, whereas the UUMZ Linnaeus specimen is not a type and identified as an undetermined species of Amnodeis Miller, 1858, similar to A. giganteus Reiche & Saulcy, 1857. The type of Tenebrio spinosus L., 1764, represents an Egyptian species, Akis spinosus (L., 1764), which has often been misidentified as Akis trilineata Herbst, 1799, a West Mediterranean species. The holotype of Tenebrio muricatus L., 1758, is Adesmia muricatus (L., 1758), comb. nov., a species appearing in recent publications as Adesmia austera Baudi di Selve, 1881, syn. nov. Two Linnean specimens preserved with the UUMZ types under the unpublished names “Tenebrio impressus” and “Tenebrio variolosus” are an undetermined species of Erodius Fabr., 1775, and Pimelia fornicata Herbst, 1799, respectively. Psammodes gibbus (L., 1760), comb. nov., is the valid name for Psammodes striatus (Fabr., 1775), syn. nov., a South African species. Pimelia gibba Fabr., 1787, and Tenebrio gibbus Pallas, 1781, are synonyms, making the current combination and attribution for this species name Moluris gibbus (Pallas, 1781). Pimelia simplex Solier, 1836, is restored as valid, resulting in changes for three subspecies names: Pimelia simplex simplex Solier, 1836, stat. rest., Pimelia simplex oasis Koch, 1941, comb. nov., and Pimelia simplex substriata Koch, 1941, comb. nov. Two new synonyms are recognized for Centorus elongatus (Herbst 1797): Calcar variabilis Gebien, 1906, syn. nov. (an unavailable subsequent usage of Tenebrio variolosus Fabr., 1801), and Tenebrio variolosus Fabr., 1801, syn. nov.

On the failure of modern species concepts

The modern age of species concepts began in 1942, when Ernst Mayr gave concept names to several different approaches to species identification. A long list of species concepts then followed, as well as a complex literature on their merits, motivations and uses. Some of these complexities arose as a consequence of the semantic shift that Mayr introduced, in which procedures for identifying species were elevated to concepts. Much of the debate in recent decades over concepts, and over pluralism versus monism, can be seen as an unnecessary consequence of treating species identification criteria as if they were more fundamental concepts. Recently, biologists have begun to recognize both the shortcomings of a lexicon of multiple species concepts and a common evolutionary idea that underlies them.

DARWINIAN METAPHYSICS: SPECIES AND THE QUESTION OF ESSENTIALISM

Biologists and philosophers of biology typically regard essentialism about species as incompatible with modern Darwinian theory. Analytic metaphysicians such as Kripke, Putnam and Wiggins, on the other hand, believe that their essentialist theses are applicable to biological kinds. I explore this tension. I show that standard anti-essentialist considerations only show that species do not have intrinsic essential properties. I argue that while Putnam and Kripke do make assumptions that contradict received biological opinion, their model of natural kinds, suitably modified, is partially applicable to biological species. However, Wiggins' thesis that organisms belong essentially to their species is untenable, given modern species concepts. I suggest that Putnam's, Kripke's and Wiggins' errors stem from adopting an account of the point of scientific classification which implies that relationally-defined kinds are likely to be of little value, an account which is inapplicable to biology.

Species concepts: a reply to Ernst Mayr

SummaryWhittemore, A. T.: Species concepts: a reply to Ernst Mayr. – Taxon 42: 573–583. 1993. – ISSN 0040‐0262.Ernst Mayr has recently analysed the flora of Concord, Massachusetts, and concluded that over 90 % of the native species of plants are well described by his “biological species concept”, which defines species as interbreeding communities that are reproductively isolated from one another. However, many of the species he considers to be good “biological species” either show little or no outcrossing or else regularly exchange genes with other species. Mayr has assessed the species of Concord, not by the two reproductive properties in his definition, but by the properties in the traditional morpho‐geographical species concept, that is, by the existence of discontinuities in the natural interpopulational variation of morphological or other markers. The flaws Mayr attributes to morphological species concepts – that taxonomists assess variation in individuals without reference to the underlying population‐genetic variation, that taxonomic species are based on overall phenetic distance rather than phenetic discontinuities, and that they grossly overestimate the frequency of natural hybridization in plants – are not part of any modern species concept, and his refutations of critics of his concepts do not adequately address the problems that exist in his definition. He is quite correct in concluding that the nature of species is similar in animals and plants, since uniparental reproduction and interspecific gene exchange are also widespread in animals. To the extent that Mayr is defending the classical morpho‐geographical approach to systematics, he is quite right, as most taxonomists have long recognized. The controversy over Mayr's biological species concept is due to his linking the morpho‐geographical approach to an inaccurate definition.