Journal of Systematics and Evolution最新文献

At the XIX International Botanical Congress held in Shenzhen, China, in July 2017, the delegates unanimously adopted the Shenzhen Declaration on Plant Sciences in an effort to accelerate the contributions made by plant scientists for the benefit of the world′s changing society. This paper discusses what has been accomplished concerning plant conservation since the Shenzhen Declaration. Beyond the problems we faced in 2017, the global Covid pandemic and the war have presented new challenges. With the massive ecological overshoot, the number of malnourished people globally has increased. Most threats to vascular plants have increased generally over these 6 years, while the responses of the botanical community to them have continued to proceed at a relatively slow pace. Although international cooperation is needed to combat the grave challenges we face, the ease of such collaboration has decreased substantially in recent years. Certainly, rapid deforestation, especially in the tropics, and our ineffective approaches to mitigate climate change will lessen the effectiveness of our strategies to slow extinction. Indeed, our blindness to the reality of ecological overshoot and misperceptions concerning sustainability are accelerating extinction and thus destabilizing social structures and civilization. As an example, conservation in China faces serious challenges with biodiversity loss, but botanical gardens and seed banks there offer hope on ex situ conservation. The botanical and other scientific communities can contribute by drawing the attention of fellow citizens to the gravity of the problems that we face and by being actively engaged in providing solutions and carrying them forward to action.

The sclerophyllous syndrome is characterized by well-defined traits (evergreen coriaceous leaves, inconspicuous flowers, and fleshy fruits). It has been hypothesized that lineages displaying the sclerophyllous syndrome show lower speciation rates than non-sclerophyllous lineages after the establishment of the mediterranean climate. Daphne gnidium displays sclerophyllous traits and some differentiation into three subspecies (gnidium, mauritanica, maritima), but the spatio-temporal origin of this taxonomic group is unknown due to the lack of a time-calibrated phylogeny of the whole genus. Here, we inferred phylogenetic relationships and divergence times of Daphne (32 species, 238 samples) and other genera of Thymelaeaceae (16 genera, 38 species, 34 samples) using the internal transcribed spacer (ITS), which revealed that the current circumscription of Daphne is profoundly polyphyletic because some species are nested within the genera Wikstroemia and Edgeworthia. In contrast, D. gnidium formed a well-supported clade as recognized in taxonomic accounts (subgenus Spachia). We found morphological and phylogenetic support for Daphne mauritanica as a monophyletic lineage sister to D. gnidium. Divergence between D. gnidium and D. mauritanica appears to have predated the establishment of seasonally dry conditions, which supports a pre-mediterranean temporal origin of the lineage. A phylogeographical analysis within D. gnidium based on 66 nrDNA (ITS) and 84 cpDNA (rps16, trnV) sequences agreed with the low differentiation of the species in the Pleistocene despite its large distribution range. Altogether, D. gnidium illustrates one more example of the sclerophyllous syndrome with no speciation after the onset of the mediterranean climate.

Banksia L.f., an iconic genus of the Proteaceae, is endemic to Australia, with its highest species richness and phylogenetic diversity (PD) in southwestern Western Australia. Analysis of the phylogenetic component of richness and endemism uncovered important patterns of Banksia evolutionary history that are not seen at the species level. We found that Banksia is significantly phylogenetically clustered in this region, likely due to recent evolutionary radiations. We also found significant concentrations of phylogenetic endemism in this region, both neoendemism (short, range-restricted evolutionary branches) and paleoendemism (long, range-restricted evolutionary branches). There is a striking northwest to southeast divide in phyloturnover in southwestern Western Australia. The majority of the variation in turnover patterns can be explained by environmental factors, with climate representing the largest covariate. This study adds to the growing body of evidence that indicates the importance of integrating phylogenetic and biodiversity data to inform conservation planning.

Newly investigated leafy twigs bearing axillary fruits from the Eocene Parachute Creek Member of the Green River Formation in eastern Utah, USA, have provided more information on the species previously attributed to the Proteaceae as Banksia comptonifolia R.W.Br. The leaves are simple, estipulate with short petioles, and elongate laminae with prominent angular nonglandular teeth. The laminae have a thick midvein and pinnate craspedodromous secondaries, and are distinctive in the presence of a thick, often coalified, marginal rim. Vegetative and reproductive buds occur in the axils of the leaves. These features indicate that the species belongs to Palibinia Korovin—an extinct Eudicot genus previously known only from the Paleogene of Asia and Europe. Small pedicellate ovoid fruits 1.5–2.2 mm wide are borne in fascicles of three and are seen to be capsules with four apical valves. Despite the specific epithet referring to similarity of the foliage to that of Comptonia (Myricaceae), the fasciculate inflorescence organization with axillary flowers is quite distinct from the catkins characteristic of that family. Assignment to Banksia or other Proteaceae with complex inflorescences and follicular fruits is also problematic. Additionally, MacGinitie′s transfer of the species to Vauquelinia of the Rosaceae is contradicted by the lack of stipule scars on the twig and by differences in leaf venation and floral morphology. We transfer the species to Palibinia comptonifolia (R.W.Br.) comb. nov., but its familial affinity within the Pentapetalae remains uncertain. This new occurrence augments records from the Paleogene of Turkmenistan, Kazakhstan, China, England, and Germany.