Species: towards new, well-grounded practices

Velasco recently criticized our formal definition of the species concept, arguing for its inappropriateness both in fundamental and practical aspects [Velasco JD (2008) Biological Journal of the Linnean Society , 93 , 865–869]. Here, we clarify some misunderstandings that are at the basis of Velasco's paper. First, we show why and how the definition of the species concept can be grounded in the theory of evolution and what that implies. Then, we explain why Velasco's formal criticisms are unjustified. Finally, we point out the practical and methodological consequences of a rigorous conceptual framework for species study, and we show that today's development of species delimitation methods fully agrees with our proposal.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 217–222.     

A new species of Cryptolepis (Apocynaceae: Periplocoideae) from Kenya and Tanzania, Africa

A new species of Cryptolepis is described from Kenya and Tanzania. It is a tropical forest climber and its unique second corona whorl of deeply cleft lobes distinguishes it from all other Cryptolepis species.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 343–346.     

The tree, the network, and the species

To enrich the Hennigian internodal conception of species, a new formalization of the definition of the species concept is proposed. This rigorous definition allows for considerable unification of the various, and sometimes conflicting, techniques of species delimitation used in practice. First, the domain of such a definition is set out, namely, the set of all organisms on Earth, past, present, and future. Next, the focus is on the genealogical relationship among organisms, which provides the key to analysing the giant or global genealogical network (GGN) connecting all these organisms. This leads to the construction of an algorithm revealing the topological structure of the GGN, from families to lineages, ending up with a definition of species as equivalence classes of organisms corresponding to branches of the 'tree of life'. Such a theoretical definition of the species concept must be accompanied by various recognition criteria to be operational. These criteria are, for example, the ill-named 'biological species concepts', 'phylogenetic species concepts', etc., usually, but wrongly, presented as definitions of the species concept. Besides clarifying this disputed point, the definition in the present study displays the huge diversity of the scales (time-scale and population size) involved in actual species, thus explaining away the classical problems raised by previous attempts at defining the species concept (uniparental reproduction, temporal depth of species, and hybridization).  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 509–521.     

On the difference between mono-, holo-, and paraphyletic groups: a consistent distinction of process and pattern

About 50 years ago, the German entomologist Willi Hennig presented a new approach in biological systematics that he called a phylogenetic systematics. The main difference between his approach and traditional Linnean systematics was that he distinguished two new kinds of groups that he called mono- and paraphyletic groups, and whereof he considered only monophyletic groups to be natural groups. However, almost immediately after publication of his approach in English, some biological systematists commented that his monophyletic groups rather ought to be called holophyletic groups. The comment sparked a heated debate about the definition of the concept 'monophyletic groups', but the debate never reached consensus. In this paper, I claim that the controversy does not concern the definition of the concept monophyletic groups per se , but instead conceptualization of phylogenies (i.e. dichotomously branching processes) in a general sense. I discuss the relation between mono-, holo- and paraphyletic groups, and conclude that Hennig's conceptualization of phylogenies is both inconsistent and empirically wrong, whereas Linné's instead is consistent and correct.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 217–220.     

'Integrative taxonomy' then and now: a response to Dayrat (2005)

Deep misunderstandings still besiege taxonomy after more than 200 years of fruitful output. It has been asserted in this journal that taxonomy should be integrative and conform to a series of restrictive guidelines. We show that taxonomy has been integrative for most of its history although, in our sense, integrative does not mean the indiscriminate pooling of any source of data. The guidelines proposed are not founded in good scientific rationale and can have, if followed, a detrimental effect not only on taxonomy, but also on biology as a whole.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 211–216.     

Pollination of Kadsura longipedunculata (Schisandraceae), a monoecious basal angiosperm, by female, pollen-eating Megommata sp. (Cecidomyiidae: Diptera) in China

The plants of Kadsura longipedunculata (Schisandraceae) are monoecious and possess either red or yellow male flowers (the androecium), with yellow tepals, and yellow female flowers. All flower types simultaneously produce heat and floral odours (dominated by methyl butyrate) throughout a 4–5-h nocturnal period. The flowers are pollinated only by female, pollen-eating Megommata sp. (Cecidomyiidae). Pollen is the only reward, and female flowers use the same attractants as male flowers but offer no food (pollination by deceit). Open pollinated flowers in nature varied in fruit set from 8 to 92%. Megommata (subfamily Cecidomyiinae, supertribe Cecidomyiidi), consists of six described species, which feed on Coccoidea (scale insects) and are distributed worldwide.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 523–536.     

A new species of Silene (Caryophyllaceae) from east Anatolia, Turkey

Silene bitlisensis O.Tugay & Ertugrul from the Green Line Afforestation Zone (B9: Bitlis Province) is a new species described and illustrated here. It is closely related to S. caramanica Boiss. & Heldr. var. ilarslanii Aytaç & Dural, from which it mainly differs in its habit, leaf, and floral features.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 463–466.     

Diel activity and reproductive isolation in a diverse assemblage of Neotropical skippers (Lepidoptera: Hesperiidae)

A sample of over 400 co-occurring species of Neotropical Hesperiidae attracted to artificial lures was used to test for temporal structure among species and explore potential consequences of temporal partitioning within assemblages. Five years of intermittent transect samples at the same site revealed that diel activity was significantly partitioned among subfamilies, genera and species within this species assemblage. Calculations of reproductive isolation indicate that partitions in activity times are sufficient to provide significant prezygotic reproductive isolation among some congeneric species pairs. Temporal patterns in this assemblage are considered in light of field observations and temporal partitions are examined as a potential isolating barrier among insects.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society 2008, 94 , 723–736.     

Caste in the swarming wasps: 'queenless' societies in highly social insects

Morphometric data for 30 species of swarming wasps (Vespidae: Polistinae: Epiponini) are presented, representing all currently recognized genera. Data are coded according to whether females that were shown by dissection to be egglayers are larger, similar, or smaller for each dimension than non-egglayers. These data are analysed in a phylogenetic framework with primitively social Polistes and Mischocyttarus as outgroups. Representative measurements are illustrated to show that most genera of Epiponini appear to have ancestry in a lineage that has no queen caste comparable with either the primitively social outgroups, or the more derived species of the tribe. This analysis indicates that a conspiracy of workers that operates without a queen characterizes the societies of many Epiponini, or their recent ancestors.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 509–522.     

Dendrobium wangliangii (Orchidaceae), a new species belonging to section Dendrobium from Yunnan, China

Dendrobium wangliangii G. W. Hu, C. L. Long & X. H. Jin, a new species from the north of the Yunnan Province in China is described and illustrated. The morphological differences between the new species and the related species, Dendrobium flexicaule , and its endangered status are discussed.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 217–221.     

Post-Pleistocene evolution of Bornean shrews Crocidura foetida (Mammalia, Soricidae)

Fossil mandibles of the Bornean shrew Crocidura foetida recovered from excavations at the west mouth of Niah cave, Sarawak, Malaysia, show that the late Pleistocene population at this lowland location was comparable in size with the large subspecies Crocidura foetida doriae , presently occurring at inland, upland locations. Two Holocene specimens fall in the size range of the smaller lowland subspecies C. f. foetida . Comparable post-Pleistocene size-reduction is known among other mammals of Borneo, but this is the first instance of dated examples. The evolutionary trend conforms with Bergmann's 'rule' but, other than climate change, no selective agent is apparent.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 413–419.     

Phenetic patterns in Poa section Dioicopoa: a new species from the Puneña and Altoandina phytogeographical provinces of Argentina

Based on multivariate analyses, a new dioecious species of Poa from the Puneña and Altoandina phytogeographical provinces of Argentina is described. This species is most similar to Poa calchaquiensis of Poa section Dioicopoa . The ligule length, plant size, and glabrous pistillate anthoecia distinguish Poa nubensis . A key for identification and illustrations are also included.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 239–248.     

Volatile chemical release by bethylid wasps: identity, phylogeny, anatomy and behaviour

The structures of volatile chemicals released by parasitic wasps in the family Bethylidae are shown to correspond to the subfamily to which the species belong. Species in the Epyrinae release skatole (3-methylindole) and species in the Bethylinae release a spiroacetal (2-methyl-1,7-dioxaspiro [5.5]undecane): these compounds are chemically very different. The enantiomeric composition of the spiroacetal differs between congeneric species. Chemical release is a discrete event under the active control of both male and female wasps. Structural differences between the mandibular glands and intramandibular glands suggest the mandibular glands to be the source of released volatiles. Real-time mass spectrometry shows that the spiroacetal is released by Goniozus nephantidis females during dyadic resource contests, with release more common during more aggressive interactions. Chemical tagging with deuterium further shows that the volatile is released by the loser of an agonistic interaction and not the winner. The function of spiroacetal and skatole release by bethylids is discussed.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 837–852.     

Arbuscular mycorrhizal fungi: genetics of multigenomic, clonal networks and its ecological consequences

Arbuscular mycorrhizal fungi are thought to have remained asexual for 400 million years, although recent studies have suggested that considerable genetic and phenotypic variation could potentially exist in populations. A brief discussion of these multigenomic organisms is presented.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79 , 59–60.     

Astragalus bahcesarayensis (Leguminosae-Papilionoideae), a new species of section Alopecuroidei DC. from Turkey

Astragalus bahcesarayensis H. Akan, M. Fırat & M. Ekici (Leguminosae-Papilionoideae) from Turkey is described and illustrated. It is compared with A. dipsaceus Bunge and A. panduratus Bunge. The geographical distributions of the new species and related species are mapped.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 439–444.     

A new species of Linum (Linaceae) from west Anatolia, Turkey

A new species, Linum vuralianum Yılmaz & Kaynak, is described and illustrated from west Anatolia, Turkey. It is closest to L. flavum L., but differs by its annual or biennial life form, the presence of rosette leaves at anthesis, and the absence of staminodes. The World Conservation Union (IUCN) threat category and observations on the population are noted. The geographical distribution of the new species and its related taxon is given.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 459–462.     

Canarian land snail diversity: conflict between anatomical and molecular data on the phylogenetic placement of five new species of Napaeus (Gastropoda, Pulmonata, Enidae)

Five new species of land snail (family Enidae) are described from La Gomera (Canary Islands) of which the majority, on the basis of anatomy alone, could be incorporated within a new supraspecific taxon. In addition to the morphological study of these new species, a region of the 16S mitochondrial gene is sequenced from three of the new species and a range of species of Napaeus from within its two subgenera ( Napaeinus and Napaeus ) . There is a disparity between the morphological and preliminary molecular phylogenetic data. Possible explanations for this conflict are discussed, as well as the evolutionary relationships among these different taxa, and it is suggested that this group may be an excellent model for further studies of adaptation and diversification.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 169–187.