Systematic position of Triplosoba,hitherto the oldest mayfly,from Upper Carboniferous of Commentry in Central France (Insecta: Palaeodictyopterida)

A revision of the holotype of Triplosoba pulchella (Brongniart, 1883), the ‘oldest mayfly’, provides evidence for new attribution to Palaeodictyopterida sensu Bechly. New character states derived from the venation pattern, namely the basal connection of the median anterior with the radius and radius posterior in the forewing, the median anterior remote from the radius posterior and basally fused with the median posterior in the hindwing, and a strong costal margin formed by two connected or fused veins with a series of small spines (costa and subcosta anterior), support an ordinal placement of Triplosoba into Palaeodictyopterida (inclusive of Diphanopterodea sensu Bechly) versus Ephemeroptera as supposed by previous authors. It shares with Diaphanopterodea a potential synapomorphy in the presence of long curved connections between the three stems of the radius, media, and cubitus in the basal part of the forewing, a character not present in other groups of Palaeodictyopterida.     

Evidence for Carboniferous origin of the order Mantodea (Insecta: Dictyoptera) gained from forewing morphology

Homologies of the forewing venation pattern of the order Mantodea (Insecta: Dictyoptera) consistent with the accepted insect wing venation groundplan are proposed. A comparative morphological analysis was carried out based on a broad taxonomic sample of extant taxa. Besides macromorphological aspects, focus is given to the pattern of the tracheal system as a basis for establishing primary homologies. All extant praying mantids exhibit a composite stem composed of the posterior radius (RP) and the media (M) and most praying mantids exhibit a fusion of the anterior branch of RP + M with the anterior radius (RA). The wing venation of the species ?Mesoptilus dolloi, previously assigned to the polyphyletic fossil assemblage ‘Protorthoptera’, is re‐interpreted in the light of the new homology statement. Our interpretation suggests that it is a putative stem‐Mantodea, as are some other ‘protorthopterous’ taxa. This hypothesis implies that the total‐group Mantodea arose as soon as the Late Carboniferous, i.e. about 175 million years earlier than previously estimated. This analysis contributes to the view that most of the Late Carboniferous ‘Protorthoptera’ are stem‐representatives of the major polyneopteran clades (e.g. cockroaches, grasshoppers and crickets, rock‐crawlers), suggesting a survivorship of several main Pterygota lineages at the end‐Permian extinction event higher than previously expected. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156 , 79–113.     

A chiton without a foot

Abstract: The palaeoloricate ‘polyplacophorans’ are an extinct paraphyletic group of basal chiton‐like organisms known primarily from their fossilized valves. Their phylogenetic placement remains contentious, but they are likely to include both stem‐group Polyplacophora and stem‐group Aplacophora. Candidates for the latter position include ‘Helminthochiton’thraivensis from the Ordovician of Scotland, which we redescribe here through a combined optical and micro‐CT (XMT) restudy of the type material. The 11 specimens in the type series are all articulated, presenting partial or complete valve series as well as mouldic preservation of the girdle armature; they demonstrate a vermiform body plan. The valves are typically palaeoloricate in aspect, but differ in detail from all existing palaeoloricate genera; we hence erect Phthipodochiton gen. nov. to contain the species. The most notable feature of the fossils is the spicular girdle; this is impersistently preserved, but demonstrably wraps entirely around the ventral surface of the animal, implying that a ‘true’ (i.e. polyplacophoran like) foot was absent, although we do not exclude the possibility of a narrow solenogastre‐like median pedal groove having been present. Phthipodochiton thraivensis presents an apparent mosaic of aplacophoran and polyplacophoran features and as such will inform our understanding of the relationship between these groups of extant molluscs. An inference may also be drawn that at least some other palaeoloricates possessed an ‘armoured aplacophoran’ body plan, in contrast to the ‘limpet‐like’ body plan of extant Polyplacophora.     

Does sample length influence the shape of xylem embolism vulnerability curves? A test with the Cavitron spinning technique

The Cavitron spinning technique is used to construct xylem embolism vulnerability curves (VCs), but its reliability has been questioned for species with long vessels. This technique generates two types of VC: sigmoid ‘s’‐shaped and exponential, levelling‐off ‘r’‐shaped curves. We tested the hypothesis that ‘r’‐shaped VCs were anomalous and caused by the presence of vessels cut open during sample preparation. A Cavitron apparatus was used to construct VCs from samples of different lengths in species with contrasting vessel lengths. The results were compared with VCs obtained using other independent techniques. When vessel length exceeded sample length, VCs were ‘r’‐shaped and anomalous. Filling vessels cut open at both ends with air before measurement produced more typical ‘s’‐shaped VCs. We also found that exposing segments of 11 woody species in a Cavitron at the pressure measured in planta before sampling considerably increased the degree of embolism above the native state level for species with long vessels. We concluded that open vessels were abnormally more vulnerable to cavitation than intact vessels. We recommend restricting this technique to species with short conduits. The relevance of our conclusions for other spinning techniques is discussed.     

Effect of Inoculum Density on Verticillium Wilt Incidence in Commercial Olive Orchards

Verticillium wilt, caused by Verticillium dahliae Kleb., is presently the most destructive disease of olive, particularly in Andalucía (southern Spain). ‘Picual’ and ‘Arbequina’ are the dominant cultivars being planted in Spain. Both cultivars are highly susceptible to the defoliating pathotype of V. dahliae when artificially inoculated by root‐dipping or stem injection. Conversely, ‘Arbequina’ is considered more resistant than ‘Picual’ based on field observations and farmer's experience. In this study, the differential reaction between of cultivars was confirmed by surveys of naturally infested orchards with different inoculum densities of the pathogen. The average percentage of affected olive trees of ‘Picual’ was 60.2%, while only 13.1% of trees of ‘Arbequina’ showed disease symptoms. Overall, the pathogen caused extensive wilting of branches and defoliation on the trees of ‘Picual’, whereas ‘Arbequina’‐infected trees showed chlorotic symptoms and slight defoliation. The relationship between inoculum density and disease incidence fit a logarithmic function for both cultivars. The percentage of affected trees of ‘Arbequina’ per year increased linearly (y = 0.3559x, R² = 0.5652, and P = 0.0195) with the inoculum density in the soil, whereas this relationship was not observed for the ‘Picual’. Planting density had no effect on disease incidence for any of the two cultivars.     

Comparative demographics of a Hawaiian forest bird community

Estimates of demographic parameters such as survival and reproductive success are critical for guiding management efforts focused on species of conservation concern. Unfortunately, reliable demographic parameters are difficult to obtain for any species, but especially for rare or endangered species. Here we derived estimates of adult survival and recruitment in a community of Hawaiian forest birds, including eight native species (of which three are endangered) and two introduced species at Hakalau Forest National Wildlife Refuge, Hawai?i. Integrated population models (IPM) were used to link mark–recapture data (1994–1999) with long‐term population surveys (1987–2008). To our knowledge, this is the first time that IPM have been used to characterize demographic parameters of a whole avian community, and provides important insights into the life history strategies of the community. The demographic data were used to test two hypotheses: 1) arthropod specialists, such as the ‘Akiapōlā‘au Hemignathus munroi, are ‘slower’ species characterized by a greater relative contribution of adult survival to population growth, i.e. lower fecundity and increased adult survival; and 2) a species’ susceptibility to environmental change, as reflected by its conservation status, can be predicted by its life history traits. We found that all species were characterized by a similar population growth rate around one, independently of conservation status, origin (native vs non‐native), feeding guild, or life history strategy (as measured by ‘slowness’), which suggested that the community had reached an equilibrium. However, such stable dynamics were achieved differently across feeding guilds, as demonstrated by a significant increase of adult survival and a significant decrease of recruitment along a gradient of increased insectivory, in support of hypothesis 1. Supporting our second hypothesis, we found that slower species were more vulnerable species at the global scale than faster ones. The possible causes and conservation implications of these patterns are discussed.     

Trubs,but no trianas: filled and empty regions of angiosperm stem length‐diameter‐mechanics space

Discrete plant habit categories such as ‘tree’, ‘shrub’, and ‘liana’ belie continuous variation in nature. To study the evolution of this continuous variation, we gathered data on stem length, diameter and tissue mechanical stiffness across a highly morphologically diverse highland xerophytic scrub on a lava flow in central Mexico. With stem allometric and mechanical data from 1216 segments from 50 species, we examined relationships between stem length–diameter proportions and tissue mechanical stiffness using linear mixed‐effects models. Rather than a series of discrete clouds in stem length–diameter–tissue stiffness space, corresponding to traditional habit categories, the plants of this xerophytic scrub formed a single continuous one. Within this cloud, self‐supporting plants had stems that became predictably longer and tissues that became stiffer for a given diameter increase, and there was no paucity of intermediates between trees and shrubs (‘trubs’). Non self‐supporting plants had a steeper stem length–diameter slope and their tissues did not increase in stiffness with stem size. The area between self‐ and non self‐supporting plants was sparsely occupied as stem size increased. We predict that this ‘empty’ space between lianas and trees is developmentally accessible but of low fitness, meaning that there should be few ‘trianas’ in nature. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 179 , 361–373.     

Multi‐locus sequence data reveal a new species of coral reef goby (Teleostei: Gobiidae: Eviota), and evidence of Pliocene vicariance across the Coral Triangle

Here, multi‐locus sequence data are coupled with observations of live colouration to recognize a new species, Eviota punyit from the Coral Triangle, Indian Ocean and Red Sea. Relaxed molecular clock divergence time estimation indicates a Pliocene origin for the new species, and the current distribution of the new species and its sister species Eviota sebreei supports a scenario of vicariance across the Indo‐Pacific Barrier, followed by subsequent range expansion and overlap in the Coral Triangle. These results are consistent with the ‘centre of overlap’ hypothesis, which states that the increased diversity in the Coral Triangle is due in part to the overlapping ranges of Indian Ocean and Pacific Ocean faunas. These findings are discussed in the context of other geminate pairs of coral reef fishes separated by the Indo‐Pacific Barrier.     

Polytomies,signal and noise: revisiting the mitochondrial phylogeny and phylogeography of the Eurasian blindsnake species complex (Typhlopidae,Squamata)

Polytomies are multifurcating nodes on a phylogenetic tree that represent unresolved relationships. Contrary to ‘hard’ polytomies that hide simultaneous splitting events, ‘soft’ polytomies can theoretically be resolved with the addition of phylogenetic signal. This is not always successful, especially when a radiation is old and rapid, because adding more signal will inevitably increase the noise. The Xerotyphlops vermicularis species complex is an example of a largely unresolved old and rapid radiation. This mtDNA phylogeny is revisited by analysing samples representative of all lineages and generating a 3700‐bp final data set, after preliminary tests found two of the analysed markers responsible for long‐branch attraction. The new enhanced data set increased phylogenetic resolution, resulting in a robust time‐calibrated phylogeny and phylogeographic conclusions. Jordan/south Syria populations separated during the Middle Miocene, and the Messinian salinity crisis (MSC) appears responsible for the second diversification wave. A third radiation occurred during the Early Pliocene, resulting in four mtDNA groups west, east and south of the Amanos mountains in east Turkey/north Syria. Finally, three hypotheses regarding the number of potential ‘species’ within the complex are made, with the most moderate ‘four species’ hypothesis fitting very well with the diversity patterns and established systematics of east Mediterranean reptiles.     

Unnecessary roughness? Testing the hypothesis that predators destined for molecular gut‐content analysis must be hand‐collected to avoid cross‐contamination

Molecular gut‐content analysis enables detection of arthropod predation with minimal disruption of ecosystem processes. Mass‐collection methods, such as sweep‐netting, vacuum sampling and foliage beating, could lead to regurgitation or rupturing of predators along with uneaten prey, thereby contaminating specimens and compromising resultant gut‐content data. Proponents of this ‘cross‐contamination hypothesis’ advocate hand‐collection as the best way to avoid cross‐contamination. However, hand‐collection is inefficient when large samples are needed, as with most ecological research. We tested the cross‐contamination hypothesis by setting out onto potato plants immature Coleomegilla maculata and Podisus maculiventris that had been fed larvae of either Leptinotarsa decemlineata or Leptinotarsa juncta, or unfed individuals of these predator species along with L. decemlineata larvae. The animals were then immediately re‐collected, either by knocking them vigorously off the plants onto a beat cloth and capturing them en masse with an aspirator (‘rough’ treatment) or by hand‐searching and collection with a brush (‘best practice’). Collected predators were transferred in the field to individual vials of chilled ethanol and subsequently assayed by PCR for fragments of cytochrome oxidase I of L. decemlineata and L. juncta. Ten to 39 per cent of re‐collected fed predators tested positive by PCR for DNA of both Leptinotarsa species, and 14–38% of re‐collected unfed predators contained L. decemlineata DNA. Overall levels of cross‐contamination in the rough (31%) and best‐practice (11%) samples were statistically different and supported the cross‐contamination hypothesis. A pilot study on eliminating external DNA contamination with bleach prior to DNA extraction and amplification gave promising results.     

Why do some species have geographically varying responses to fire history?

A capacity to predict the effects of fire on biota is critical for conservation in fire‐prone regions as it assists managers to anticipate the outcomes of different approaches to fire management. The task is complicated because species’ responses to fire can vary geographically. This poses challenges, both for conceptual understanding of post‐fire succession and fire management. We examine two hypotheses for why species may display geographically varying responses to fire. 1) Species’ post‐fire responses are driven by vegetation structure, but vegetation – fire relationships vary spatially (the ‘dynamic vegetation’ hypothesis). 2) Regional variation in ecological conditions leads species to select different post‐fire ages as habitat (the ‘dynamic habitat’ hypothesis). Our case study uses data on lizards at 280 sites in a ～ 100 000 km² region of south‐eastern Australia. We compared the predictive capacity of models based on 1) habitat associations, with models based on 2) fire history and vegetation type, and 3) fire history alone, for four species of lizards. Habitat association models generally out‐performed fire history models in terms of predictive capacity. For two species, habitat association models provided good discrimination capacity even though the species showed geographically varying post‐fire responses. Our results support the dynamic vegetation hypothesis, that spatial variation in relationships between fire and vegetation structure results in regional variation in fauna–fire relationships. These observations explain how the widely recognised ‘habitat accommodation’ model of animal succession can be conceptually accurate yet predictively weak.     

Morphology agrees with molecular data: phylogenetic affinities of Euptychiina butterflies (Nymphalidae: Satyrinae)

Euptychiina is the most species‐rich subtribe of Neotropical Satyrinae, with over 450 known species in 47 genera (14 monotypic). Here, we use morphological characters to examine the phylogenetic relationships within Euptychiina. Taxonomic sampling included 105 species representing the majority of the genera, as well as five outgroups. A total of 103 characters were obtained: 45 from wing pattern, 48 from genitalia and 10 from wing venation. The data matrix was analysed using maximum parsimony under both equal and extended implied weights. Euptychiina was recovered as monophyletic with ten monophyletic genera, contrasting previous DNA sequence‐based phylogenies that did not recover the monophyly of the group. In agreement with sequence‐based hypotheses, however, three main clades were recognized: the ‘Megisto clade’ with six monophyletic and three polyphyletic genera, the ‘Taygetis clade’ with nine genera of which three were monophyletic, and the ‘Pareuptyhia clade’ with four monophyletic and two polyphyletic genera. This is the first morphology‐based phylogenetic hypothesis for Euptychiina and the results will be used to complement molecular data in a combined analysis and to provide critical synapomorphies for clades and genera in this taxonomically confused group.     

Bird–flower interactions in the Macaronesian islands

Aims Several bird‐pollinated or ornithophilous flowers are present on the Macaronesian archipelagos, the Canary Islands and Madeira, but absent from nearby NW Africa and Europe. In Macaronesia, no specialist nectar‐feeding birds are found, but several generalist passerine bird species visit flowers for nectar. Two hypotheses attempt to explain the origin and evolution of ornithophily in the Macaronesian flora. According to ‘the island de novo hypothesis’, bird‐flowers evolved from mainland insect‐pollinated ancestors after island colonization. Alternatively, ancestors of the ornithophilous Macaronesian plant species evolved bird‐flowers before reaching the islands (‘the relict hypothesis’). In this study we first compile information of Macaronesian bird–flower interactions from the literature and our own field observations. Secondly, we discuss the two hypotheses of origin of ornithophily in the light of evidence from recent molecular plant phylogenies, palaeontology, historical biogeography of the African avifauna and flora, and present‐day ecological patterns. Location Madeira and Canary Islands. Results At least eleven endemic Macaronesian plant species from six genera have typical ornithophilous floral traits. These genera are: Canarina and Musschia (Campanulaceae), Isoplexis (Scrophulariaceae), Echium (Boraginaceae), Lotus (Fabaceae) and Lavatera (Malvaceae). These lineages have clear affinities to the Mediterranean region, except for Canarina whose closest relatives grow in East African mountains. Six generalist passerine bird species of Sylvia, Phylloscopus (Sylviidae), Serinus (Fringillidae) and Parus (Paridae) visit this flora for nectar. Main conclusion We suggest that the origin and evolution of ornithophilous traits in these plant species took place mostly in mainland areas prior to island colonization. In Canarina and Lavatera, it is well supported that ornithophily is a relict condition, which originated in mainland areas possibly in association with specialist nectar‐feeding birds. For the remaining plant species except Echium wildpretii bird floral traits probably also are a relict condition. These species may be derived from ancestors, which were visited by specialist nectar‐feeding birds during geological periods when the Mediterranean and the Ethiopian vegetation were intermingled in mainland Africa. Probably, these mainland ancestors went extinct due to severe climatic fluctuations, while their Macaronesian descendants survived in ‘refuge’ on the islands. Finally, the island de novo hypothesis may explain the evolution of a mixed bird/insect‐pollination system in the neo‐endemic red‐flowered Echium wildpretii.     

Exposing hidden endemism in a Neotropical forest raptor using citizen science

Gaps in our knowledge of the geographical distribution of species represent a fundamental challenge to biogeographers and conservation biologists alike, and are particularly pervasive in the tropics. Here we highlight the case of the Rufous‐thighed Kite Harpagus diodon, a South American raptor commonly mapped as resident across half the continent. Recent observations at migration watch points have indicated it may be partially migratory in the southernmost parts of its range. To investigate this possibility, we collated contemporary and historical specimen records, published sight records and ‘digital vouchers’ – photographs and sound‐recordings archived online (from citizen science initiatives) – and explored the spatiotemporal distribution of records. We were unable to trace any documented records of this species from Amazonia during the austral summer (October–March), or records from the Atlantic Forest biome during the peak of the Austral winter (June–August), and all proven breeding records stem from the Atlantic Forest region. We compared this pattern with that of a ‘control’ species, the congeneric Double‐toothed Kite H. bidentatus, again using specimens and digital vouchers. For this species we found no evidence of seasonality between biomes and can disregard spatiotemporal variation in observer effort as a cause of seasonal biases. We consider that all populations of Rufous‐thighed Kites are fully migratory, wintering in Equatorial forests in the Amazonian basin. We provide evidence that this pattern was previously obscured by erroneous undocumented records and poor or erroneous specimen metadata, and its discovery was primarily facilitated by digital vouchers. This discovery requires a reassessment of the species’ global conservation status as an Atlantic Forest breeding endemic, threatened by habitat loss and degradation, as it was previously considered to be resident across large swathes of undisturbed Amazonian Forest on the Guiana Shield. The bulk of the digital voucher data used to elucidate this pattern were extracted from a Brazilian citizen science initiative WikiAves, which may serve as a model for collating biodiversity data in megadiverse countries and help catalyse environmental awareness.     

Predicting species distributions from checklist data using site‐occupancy models

Aim (1) To increase awareness of the challenges induced by imperfect detection, which is a fundamental issue in species distribution modelling; (2) to emphasize the value of replicate observations for species distribution modelling; and (3) to show how ‘cheap’ checklist data in faunal/floral databases may be used for the rigorous modelling of distributions by site‐occupancy models. Location Switzerland. Methods We used checklist data collected by volunteers during 1999 and 2000 to analyse the distribution of the blue hawker, Aeshna cyanea (Odonata, Aeshnidae), a common dragonfly in Switzerland. We used data from repeated visits to 1‐ha pixels to derive ‘detection histories’ and apply site‐occupancy models to estimate the ‘true’ species distribution, i.e. corrected for imperfect detection. We modelled blue hawker distribution as a function of elevation and year and its detection probability of elevation, year and season. Results The best model contained cubic polynomial elevation effects for distribution and quadratic effects of elevation and season for detectability. We compared the site‐occupancy model with a conventional distribution model based on a generalized linear model, which assumes perfect detectability (p = 1). The conventional distribution map looked very different from the distribution map obtained using site‐occupancy models that accounted for the imperfect detection. The conventional model underestimated the species distribution by 60%, and the slope parameters of the occurrence–elevation relationship were also underestimated when assuming p = 1. Elevation was not only an important predictor of blue hawker occurrence, but also of the detection probability, with a bell‐shaped relationship. Furthermore, detectability increased over the season. The average detection probability was estimated at only 0.19 per survey. Main conclusions Conventional species distribution models do not model species distributions per se but rather the apparent distribution, i.e. an unknown proportion of species distributions. That unknown proportion is equivalent to detectability. Imperfect detection in conventional species distribution models yields underestimates of the extent of distributions and covariate effects that are biased towards zero. In addition, patterns in detectability will erroneously be ascribed to species distributions. In contrast, site‐occupancy models applied to replicated detection/non‐detection data offer a powerful framework for making inferences about species distributions corrected for imperfect detection. The use of ‘cheap’ checklist data greatly enhances the scope of applications of this useful class of models.     

Scab resistance in ‘Geneva’ apple is conditioned by a resistance gene cluster with complex genetic control

Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most severe diseases of apple worldwide. It is the most studied plant–pathogen interaction involving a woody species using modern genetic, genomic, proteomic and bioinformatic approaches in both species. Although ‘Geneva’ apple was recognized long ago as a potential source of resistance to scab, this resistance has not been characterized previously. Differential interactions between various monoconidial isolates of V. inaequalis and six segregating F1 and F2 populations indicate the presence of at least five loci governing the resistance in ‘Geneva’. The 17 chromosomes of apple were screened using genotyping‐by‐sequencing, as well as single marker mapping, to position loci controlling the V. inaequalis resistance on linkage group 4. Next, we fine mapped a 5‐cM region containing five loci conferring both dominant and recessive scab resistance to the distal end of the linkage group. This region corresponds to 2.2 Mbp (from 20.3 to 22.5 Mbp) on the physical map of ‘Golden Delicious’ containing nine candidate nucleotide‐binding site leucine‐rich repeat (NBS‐LRR) resistance genes. This study increases our understanding of the complex genetic basis of apple scab resistance conferred by ‘Geneva’, as well as the gene‐for‐gene (GfG) relationships between the effector genes in the pathogen and resistance genes in the host.     

Evolutionary islands in the Andes: persistence and isolation explain high endemism in Andean dry tropical forests

Aim The tropical Andes are a world biodiversity hotspot. With diverse biomes and dramatic, geologically recent mountain uplift, they offer a system to study the relative contributions of geological and biome history to species richness. There are preliminary indications that historical species assembly in the Andes has been influenced by physiographical heterogeneity and that distinct biomes have evolved in relative isolation despite physical proximity. Here we test this ‘Andean biotic separation hypothesis’ by focusing on the low‐elevation, seasonally dry tropical forest (SDTF) biome to determine whether patterns of plant diversification within the SDTF differ from those in mid‐ and high‐elevation biomes. Location Tropical Andes, South America. Methods Densely sampled time‐calibrated phylogenies for five legume genera (Amicia, Coursetia, Cyathostegia, Mimosa and Poissonia) containing species endemic to the Andean SDTF biome were used to investigate divergence times and levels of geographical structure. Geographical structure was measured using isolation‐by‐distance methods. Meta‐analysis of time‐calibrated phylogenies of Andean plant groups was used to compare the pattern and tempo of endemic species diversification between the major Andean biomes. Results Long‐term persistence of SDTF in the Andes is suggested by old stem ages (5–27 Ma) of endemic genera/clades within genera, and deep divergences coupled with strong geographical structure among and within species. Comparison of species diversification patterns among different biomes shows that the relatively old, geographically confined pattern of species diversification in SDTF contrasts with the high‐elevation grasslands that show rapid and recent radiations driven by ecological opportunities. Main conclusions The SDTF biome has a long history in the Andes. We suggest that the diverse SDTF flora has been assembled gradually over the past c. 19 Ma from lineages exhibiting strong phylogenetic niche conservatism. These patterns suggest that Andean SDTFs have formed stable and strongly isolated ‘islands’ despite the upheavals of Andean uplift. Indeed, the Andean SDTFs may represent some of the most isolated and evolutionarily persistent continental plant communities, similar in many respects to floras of remote oceanic islands.