Species Concepts and Species Delimitation

AbstractWe provide an expanded and updated, 2-locus phylogeny (mtSSU, nuLSU) of the lichenized fungal family Trypetheliaceae, with a total of 196 ingroup OTUs, in order to further refine generic delimitations and species concepts in this family. As a result, the following 15 clades are recognized as separate genera, including five newly established genera: Aptrootia, Architrypethelium, Astrothelium (including the bulk of corticate species with astrothelioid ascospores; synonyms: Campylothelium, Cryptothelium, Laurera), Bathelium s. str. (excluding B. degenerans and relatives which fall into Astrothelium), the reinstated Bogoriella (for tropical, lichenized species previously placed in Mycomicrothelia), Constrictolumina gen. nov. (for tropical, lichenized species of Arthopyrenia), Dictyomeridium gen. nov. (for a subgroup of species with muriform ascospores previously placed in Polymeridium), Julella (provisionally, as the type species remains unsequenced), Marcelaria (Laurera purpurina complex), Nigrovothelium gen. nov. (for the Trypethelium tropicum group), Novomicrothelia gen. nov. (for an additional species previously placed in Mycomicrothelia), Polymeridium s. str., Pseudopyrenula, Trypethelium s. str. (T. eluteriae group), and Viridothelium gen. nov. (for the Trypethelium virens group). All recognized genera are phenotypically characterized and a discussion on the evolution of phenotypic features in the family is given. Based on the obtained phylogeny, species delimitations are revised and the importance of characters such as thallus morphology, hymenial inspersion, and secondary chemistry for taxonomic purposes is discussed, resulting in a refined species concept.

Download Full-text

Novel Approaches for Species Concepts and Delimitation in Polyploids and Hybrids

Plants ◽

10.3390/plants11020204 ◽

2022 ◽

Vol 11 (2) ◽

pp. 204

Author(s):

Elvira Hörandl

Keyword(s):

Sexual Reproduction ◽

Species Delimitation ◽

Species Concepts ◽

Plant Evolution ◽

Polyploid Species ◽

Ecological Adaptations ◽

As Species ◽

Novel Approaches ◽

Conceptual Progress

Hybridization and polyploidization are important processes for plant evolution. However, classification of hybrid or polyploid species has been notoriously difficult because of the complexity of processes and different evolutionary scenarios that do not fit with classical species concepts. Polyploid complexes are formed via combinations of allopolyploidy, autopolyploidy and homoploid hybridization with persisting sexual reproduction, resulting in many discrete lineages that have been classified as species. Polyploid complexes with facultative apomixis result in complicated net-work like clusters, or rarely in agamospecies. Various case studies illustrate the problems that apply to traditional species concepts to hybrids and polyploids. Conceptual progress can be made if lineage formation is accepted as an inevitable consequence of meiotic sex, which is established already in the first eukaryotes as a DNA restoration tool. The turnaround of the viewpoint that sex forms species as lineages helps to overcome traditional thinking of species as “units”. Lineage formation and self-sustainability is the prerequisite for speciation and can also be applied to hybrids and polyploids. Species delimitation is aided by the improved recognition of lineages via various novel -omics methods, by understanding meiosis functions, and by recognizing functional phenotypes by considering morphological-physiological-ecological adaptations.

Download Full-text

PUCCINIA KARELICA AND SPECIES DELIMITATION IN THE UREDINALES

Canadian Journal of Botany ◽

10.1139/b65-027 ◽

1965 ◽

Vol 43 (2) ◽

pp. 231-238 ◽

Cited By ~ 4

Author(s):

D. B. O. Savile

Keyword(s):

United States ◽

British Columbia ◽

Related Species ◽

Species Delimitation ◽

Species Concepts ◽

Distinct Population ◽

Eastern Canada ◽

Closely Related Species ◽

Typical Form ◽

Coastal British Columbia

The problem of species concepts and delimitation in the heteroecious rusts is discussed. It is illustrated by Puccinia karelica, which is known in typical form from Europe, southern Alaska, coastal British Columbia, and apparently Kamchatka and Saghalien. A distinct population in eastern Canada and adjacent United States is named ssp. laurentina ssp. nov. P. karelica is compared with closely related species and its probable mode of evolution is discussed.

Download Full-text

Species delimitation in Noccaea densiflora species complex (Brassicaceae) based on morphological and molecular data

Botany ◽

10.1139/cjb-2020-0184 ◽

2021 ◽

Author(s):

Kurtuluş Özgişi ◽

Burcu Tarıkahya-Hacıoğlu ◽

Atila Ocak

Keyword(s):

Species Delimitation ◽

Species Complex ◽

Principal Component ◽

Haplotype Network ◽

Molecular Data ◽

Species Concepts ◽

Accurate Identification ◽

Network Analyses ◽

Advantages And Disadvantages ◽

Multispecies Coalescent

The accurate identification of an organism is the basis of all biological disciplines. Although there have been many different species concepts and methods proposed, researchers generally choose the most appropriate concept according to their interests. However, each species concept has both advantages and disadvantages. In such cases, an integrated concept based on evidence obtained from different species concepts and methods is suitable for the accurate delimitation of a species. The biggest dilemma of integrated species delimitation methods is the inconsistency between species concepts and methods. Herein, the congruency of the different concepts and methods was tested to reveal the relationship of the Noccaea densiflora species complex. nrITS, chloroplast trnL-F, and trnQ-5'rps16 regions were used for species delimitation using the multispecies coalescent model (MSC) as implemented in two developed Bayesian Methods. ITS and trnL-F regions were also used for TCS haplotype network analyses. In addition to morphological measurements from different populations and vouchers, specific bioclimatic data values were also used for the principal component analysis. Based on all of the analyses, it was determined that only one population of N. densiflora and and one of N. microstyla were clearly distinct, whereas the rest of the specimens remain taxonomically uncertain.

Download Full-text