Molecular phylogenetics of Vandeae (Orchidaceae) and the evolution of leaflessness

Members of tribe Vandeae (Orchidaceae) form a large, pantropical clade of horticulturally important epiphytes. Monopodial leafless members of Vandeae have undergone extreme reduction in habit and represent a novel adaptation to the canopy environment in tropical Africa, Asia, and America. To study the evolution of monopodial leaflessness, molecular and structural evidence was used to generate phylogenetic hypotheses for Vandeae. Molecular analyses used sequence data from ITS nrDNA, trnL-F plastid DNA, and matK plastid DNA. Maximum parsimony analyses of these three DNA regions each supported two subtribes within monopodial Vandeae: Aeridinae and a combined Angraecinae + Aerangidinae. Adding structural characters to sequence data resulted in trees with more homoplasy, but gave fewer trees each with more well-supported clades than either data set alone. Two techniques for examining character evolution were compared: (1) mapping vegetative characters onto a molecular topology and (2) tracing vegetative characters onto a combined structural and molecular topology. In both cases, structural synapomorphies supporting monopodial Vandeae were nearly identical. A change in leaf morphology (usually reduced to a nonphotosynthetic scale), monopodial growth habit, and aeration complexes for gas exchange in photosynthetic roots seem to be the most important characters in making the evolutionary transition to leaflessness.     

Cytotaxonomy of the monopodial orchids of the African and Malagasy regions

The three subtribes which are recognized within the tribe Vandeae are represented in the tropical African and Malagasy regions. All taxa of the Vandeae have a monopodial growth habit. The first subtribe, Sarcanthinae, is mainly Asian-Australasian, but a few of its species occur in Madagascar and in Africa. The other two subtribes. Angraecinae and Aerangidinae, are both represented in the latter two regions. The Angraccinae is characterized by the presence of a short rostellum, but this is elongated in the Aerangidinae. According to earlier authors there is a correlation between presence of the short rostellum and a basic chromosome number of x=19 in the Angraecinae, and between the presence of an elongated rostellum and a basic number of x=25 in the Aerangidinae. The results presented in this paper are placed in perspective with the chromosome numbers recorded by other authors. From the resulting chromosome number survey it appears that only part of the Angraecinae (Aeranthes, several species of Angraecum, Cryptopus and Jumellea) have a basic number of x=19; some members of the Angraecinae (other species of Angraecum) were found to have a basic number of x=21, 24 and 25. The Aerangidinae is not characterized by a single basic number of x=25 but by a series ranging from x=23 to x=27, of which x=23, 24 and 25 are the most frequent. The genus Calyptrochilum, although having a distinetly elongated rostellum, is characterized by a basic number of x=19 and its position within the Aerangidinae may therefore be questioned. The present evidence suggests that too much weight has been attributed to a single character, i.e. the shape of the rostellum, in distinguishing the two subtribes. As there appear to be two groups according to basic number in Angraecum, it appears questionable whether Angraecum, as presently conceived, is a ‘natural’ genus. Further chromosomal and other taxonomic evidence is needed to substantiate the challenge to the present views in respect of Angraecum. Taxa with x=19 appear to be frequent in Madagascar and the other islands in the Indian Ocean, whereas taxa with x=21 to 27 mainly occur on the African continent. The predominance of x=19 in the Malagasy flora suggests a link with the monopodial taxa of the Asian and Australasian floras, which are exclusively based on x=19.     

A new species of Magnolia sect. Tulipastrum (Magnoliaceae) from Fujian, China

Magnolia polytepala Law, R.Z. Zhou & R.J. Zhang sp. nov. (Magnoliaceae) a new species from Fujian, south-east China, is described and illustrated. The species was found growing only in the evergreen broad-leaved forests of Mount Wuyishan at altitudes of 500–1200 m. Notes are also presented on the phenology and conservation status of the new species. It is closely related to Magnolia liliiflora Desr., but differs from the latter in its stunted habit (less than 2 m tall) and tepals, which are more numerous (12–16) and not contorted at the base.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 289–292.     

Phylogenetic analyses of mtDNA sequences reveal three cryptic lineages in the widespread neotropical frog Leptodactylus fuscus (Schneider, 1799) (Anura, Leptodactylidae)

Leptodactylus fuscus is a neotropical frog ranging from Panamá to Argentina, to the east of the Andes mountains, and also inhabiting Margarita, Trinidad, and the Tobago islands. We performed phylogenetic analyses of 12S rRNA, 16S rRNA, tRNA-Leu, and ND1 mitochondrial (mt) DNA sequences from specimens collected across the geographic distribution of L. fuscus to examine two alternative hypotheses: (i) L. fuscus is a single, widely distributed species, or (ii) L. fuscus is a species complex. We tested statistically for geographic association and partitioning of genetic variation among mtDNA clades. The mtDNA data supported the hypothesis of several cryptic species within L. fuscus. Unlinked mtDNA and nuclear markers supported independently the distinctness of a 'northern' phylogenetic unit. In addition, the mtDNA data divided the southern populations into two clades that showed no sister relationship to each other, consistent with high differentiation and lack of gene flow among southern populations as suggested by allozyme data. Concordance between mtDNA and allozyme patterns suggests that cryptic speciation has occurred in L. fuscus without morphological or call differentiation. This study illustrates a case in which lineage splitting during the speciation process took place without divergence in reproductive isolation mechanisms (e.g. advertisement call in frogs), contrary to expectations predicted using a biological species framework.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 87 , 325–341. No claim to original US government works.     

Mitochondrial differentiation, introgression and phylogeny of species in the Tegenaria atrica group (Araneae: Agelenidae)

The relationships between the three members of the Tegenaria atrica group ( T. atrica , T. saeva and T. gigantea ) were examined with DNA sequence data from mitochondrial CO1, 16S rRNA, tRNA^leu(CUN) and ND1 genes. Members of this group of large house spiders have overlapping distributions in western Europe and hybridize with each other to a variable degree. The close relatedness of all three species was supported by all analyses. T. saeva and T. gigantea are more closely affiliated than either is to T. atrica . Haplotypes clearly assignable to T. gigantea were also present in many specimens of T. saeva , suggesting asymmetrical introgression of mtDNA from T. gigantea into T. saeva . Molecular clock calibrations (CO1) suggest that deeper divisions within the genus Tegenaria may be in excess of 10 million years old, and that the evolutionary history of the T. atrica group has been moulded by Quaternary glacial–interglacial cycles.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 79–89.     

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.     

Molecular evidence for repeated hybridization events involved in the origin of the genus × Crepidiastrixeris (Asteraceae) using RAPDs and ITS data

We investigated the hybrid origin of × Crepidiastrixeris denticulato-platyphylla using RAPDs and ITS sequence data. The putative parents Paraixeris denticulata and Crepidiastrum platyphyllum represent separate species, irrespective of geographical origin. The occurrence of species specific RAPD markers from P. denticulata and C. platyphyllum in × C. denticulato-platyphylla established unambiguously a hybrid origin between the two taxa. This was in line with the occurrence of a combination of morphological characters such as plant habit and floret numbers. The parent taxa differed from each other by 7 nucleotide substitutions and 2 indel events in the ITS region. The hybrids showed sequence additivity and most likely represent F₁ plants, with the exception of two plants which were of possible F₂ origin, possessing either the ITS sequences of one parent only, or one predominant ITS type. The hybrids occurred in two out of three localities where the parents occurred sympatrically. This fact, together with the short life-span of the plants, suggests that × C. denticulato-platyphylla exists as a result of repeated, frequent hybridization between the parent species.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 333–343.     

Khaosokia caricoides, a new genus and species of Cyperaceae from Thailand

Khaosokia caricoides , D.A. Simpson, Chayam. & J. Parn., a newly discovered genus and species of Cyperaceae is described and illustrated. The genus is characterized by a narrowly paniculate dioecious inflorescence with 2–4 nodes, each of the nodes having a leaf-like inflorescence bract that exceeds the inflorescence. Spikelets in both sexes are linear-cylindric and each flower has seven perianth bristles. The nutlet was immature in the specimens examined. The photosynthetic pathway is C₃. Khaosokia is endemic to limestone cliffs in peninsular Thailand; its conservation status is assessed as Vulnerable (VU B1a + 2a). It has affinities to tribes Cariceae, Dulichieae and some members of Scirpeae, but the exact nature of these relationships has yet to be determined. A revised key to the genera of Cyperaceae in Thailand is presented.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 357–364.     

Evolution of epiphytes in Davalliaceae and related ferns

The evolution of epiphytes in Davalliaceae was investigated by field observations and molecular phylogenetic analyses. Field studies revealed that in Davalliaceae and related ferns, epiphytes in a broad sense are classified into climber, secondary hemi-epiphyte, and obligate epiphyte, based on combinations of the places (ground vs. tree) of inferred spore germination and sporophyte growth. Some species of Davalliaceae have multiple life forms, i.e. secondary hemi-epiphyte and obligate epiphyte, whereas others are obligate epiphytes. Phylogenetic trees obtained from rbcL and accD gene sequences supported that secondary hemi-epiphytic Oleandra is sister to the epiphytic Davalliaceae and polygrammoid ferns. Analyses of life form evolution based on the phylogenetic relationships suggested that obligate epiphytes of the Davalliaceae and polygrammoid ferns evolved from secondary hemi-epiphytes, or less likely from climbers. We hypothesized a scenario for the evolution of life forms in Davalliaceae and related groups that involves successive changes in rhizome habit, root function, and germination place. Rhizome dorsiventrality and scale morphology, shared by climbers, secondary hemi-epiphytes, and obligate epiphytes examined, may be other innovations for the ferns to have evolved into epiphytes.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 495–510.     

The brine shrimp's tale: a topsy turvy evolutionary fable

It has been suggested that: (1) the brine shrimp, Artemia (Branchiopoda: Anostraca), which habitually swims inverted, has 'only recently turned over'; (2) if this habit were to persist for tens of millions of years, original dorsal–ventral homologies would become obliterated; (3) it would become necessary to re-define the concept of dorsal and ventral because so many details would have changed over evolutionary time; and (4) if modern brine shrimps were to maintain the habit of swimming upside down for 100 Myr into the future, they might give rise to a whole new subkingdom whose descendants would be defined as having a dorsal nerve cord. However, brine shrimps and their allies have not recently turned over. All the nearly 300 extant anostracans swim inverted, and members of the order have clearly done so for more than 400 Myr, yet their anatomical arrangements are the same as in crustaceans that live dorsal side up. Nor do crustaceans that swim inverted and even hang from the surface film depart from the standard arrangement. The claim that inverted swimming became a genetically determined attribute of brine shrimps via the operation of the so-called Baldwin effect is rejected, as is the concept itself.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 88 , 377–382.     

Reappraisal of the ill-defined Liassic pteridosperm Dichopteris using an ultrastructural approach

This review of the genus Dichopteris De Zigno is based on the original fossil specimens collected from the Lower Jurassic of the Grey Limestones of Veneto (Northern Italy). The cuticular diagnosis of the genus is emended and only Dichopteris visianica De Zigno is retained within the genus. In addition, transverse and longitudinal sections of cuticles examined using a transmission electron microscope (TEM) indicate close similarities between D. visianica and other pteridosperm cuticles, especially the occurrence of granules arranged in areas of different densities in the epidermal cells and stomatal apparatus. Moreover, the dichotomy and the impressive size of the frond of D. visianica imply a specific architecture with a typical arrangement of the pinnae and pinnules. They preclude an herbaceous habit for the plant. Finally, architectural, microstructural and ultrastructural observations are consistent with palaeoclimatic and palaeoenvironmental data, and most probably support an understorey habit for D. visianica .  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 313–332.     

Multivariate analysis of morphological variation in Cineraria deltoidea (Asteraceae, Senecioneae)

Cluster analysis and principal coordinates analysis were used to investigate phenetic variation in Cineraria deltoidea , a species that ranges from near sea level in KwaZulu-Natal, South Africa, to 4300 m a.s.l. on the mountains of East Africa and Ethiopia. Earlier taxonomic revisions reduced nine previously recognized species to synonyms of C. deltoidea . Two closely related species, C. decipiens and C. atriplicifolia , were also included in the analyses. Thirty-six morphological characters were examined on 111 specimens. Phenograms and scattergrams show partial clusters of specimens of C. deltoidea from individual mountains or geographical regions, but no groups are sufficiently distinct to warrant formal recognition at any rank. The East African specimens from 3000 m a.s.l. and higher tend to cluster together. Growth at high altitude in East Africa is correlated with fewer, larger capitula on longer peduncles, and an absence of a cobwebby indumentum comprising long, narrow-based trichomes. Cineraria deltoidea is thus a highly variable species with geographical and clinal variation evident throughout its range. Cineraria atriplicifolia and C. decipiens are maintained as distinct species, distinguished from C. deltoidea by their growth form, life span and auricle shape.  © 2007 University of the Witwatersrand, Johannesburg. Journal compilation © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 497–521.     

The sciarid fauna of the British Isles (Diptera: Sciaridae), including descriptions of six new species

The results of a revision of the Sciaridae (Diptera: Nematocera) from the British Isles are presented, carried out as a preliminary to the preparation of a new Handbook for the identification of the British and Irish fauna of this family. A total fauna of 263 species is confirmed, including many species new to the British Isles: 111 new to Great Britain and 32 new to Ireland. Epidapus ( Pseudoaptanogyna ) echinatum Mohrig & Kozánek, 1992 , hitherto known only from North Korea, is newly recorded from Europe. Six species are described as new to science: Bradysia austera Menzel & Heller sp. nov. , Bradysia ismayi Menzel sp. nov. , Bradysia nigrispina Menzel sp. nov. , Corynoptera flavosignata Menzel & Heller sp. nov. , Corynoptera uncata Menzel & Smith sp. nov. and Epidapus subgracilis Menzel & Mohrig sp. nov . The following new synonymies are proposed: Leptosciarella nigrosetosa (Freeman, 1990) =  Leptosciarella truncatula Mohrig & Menzel, 1997 ; Sciara nursei Freeman, 1983 =  Sciara ulrichi Menzel & Mohrig, 1998. Many misidentifications in the previous literature are corrected. Details of the collection data and location of specimens examined are provided under each species. The localities from which Sciaridae were collected in the British Isles are documented by modern county and grid references and the habitat indicated where known, to assist in assessing the ecological requirements of each species.  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 146 , 1–147.     

Character divergences and convergences in canopy-dwelling Loranthaceae

The Loranthaceae is the largest plant family with aerial branch parasites termed mistletoes. Three genera of Loranthaceae are terrestrial root parasites and the remaining 72 genera are aerial parasites. Several characters, including habit, haustorial type, germination pattern, pollen morphology, chromosome number, inflorescence morphology and flower merosity, fusion, symmetry and size, are considered to reflect evolutionary relationships within the family. Convergence is a common evolutionary pattern and can confound interpretations of evolution. We investigated character evolution by mapping character states onto a phylogenetic tree based on the nuclear ITS and chloroplast trnL–trnF regions. Convergences in form were found in several characters, including habit, haustorial type, flower symmetry and merosity. These convergences typically correspond to ecological parameters such as pollination syndrome or stresses associated with the canopy habit. Other characters such as chromosome number and germination pattern illustrate divergent evolution among clades.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 101–113.     

Functional morphology and light-gathering ability of podocopid ostracod eyes and the palaeontological implications

The optical features of lateral ocelli of the eye were examined in 29 Recent species of the major ostracod group Podocopida using a theoretical morphological model. A cuticular lens–tapetum model was used for this purpose. Ray tracing was simulated on each model in order to assess the light-gathering abilities of the various forms of eyes. The results of computer simulations and morphospace analyses indicated that the light-gathering ability of the eye is dominantly affected by the thickness and curvature of the outer surface of the lens. On the basis of a combination of form and light-gathering ability, four eye types (LG1, LG2, MG, and HG) were recognized. The results of the phototactic experiment and the light intensity from each microhabitat were concordant with estimated scores on the light-gathering abilities using the theoretical models. Phylogenetic analyses and the fossil record indicate that the MG type is the most plesiomorphic, and that the other types derive from this. The present study also suggests that the optical structure that determines the light-gathering ability is closely related to the development of surface ornamentation on the valve.  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 147 , 97–108.     

Functional leaf anatomy of Bomarea Mirb. (Alstroemeriaceae)

The leaf anatomy of Bomarea is described and related to ecological conditions. The principal architecture of all species is very similar; adaptations are developed in numerous differences, for instance degree of lignification. All species have inverse leaves, the adaxial side being the stomatous side. In most species, the leaves are resupinate, the lower surface being the adaxial. Theories for the cause of resupination are discussed.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 73–90.     

A new species of Arctotis (Compositae, Arctotideae) from kommetjie grassland in Eastern Cape Province, South Africa

Arctotis debensis R.J.McKenzie, a new species from the Albany Centre of Floristic Endemism, South Africa, is described and illustrated. It grows almost exclusively in grassland on kommetjies, a distinctive landform of depressions and mounds associated with giant earthworms, in a restricted area west of King William's Town, Eastern Cape Province. It is the first plant taxon reported to be endemic or near-endemic to this unusual habitat. The new species appears to have been collected rarely and previous collections examined have remained undetermined to species level. The new species is distinguished from closely allied species by the combination of its usually larger dimensions in all parts, prostrate habit, coriaceous leaves that are green, scabrous, and eglandular on the adaxial surface and densely lanate on the abaxial surface, and involucral-bract morphology.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 581–588.