Four New Species of Anisotes (Acanthaceae) from Madagascar

Four species of Anisotes Nees (Acanthaceae) are described from northern and west-central Madagascar: A. hygroscopicus T. F. Daniel, Letsara & Martín-Bravo, A. perplexus T. F. Daniel, Letsara & Martín-Bravo, A. subcoriaceus T. F. Daniel, Letsara & Martín-Bravo, and A. venosus T. F. Daniel, Letsara & Martín-Bravo. A key to the six species of the genus known from Madagascar, all of them endemic to the island, is provided. Morphological features previously unknown in the genus are noted for A. hygroscopicus and A. venosus (hygroscopic trichomes on seeds), A. subcoriaceus (2-colporate, pseudocolpate pollen lacking insulae), and A. perplexus (2-pororate pollen). None of these species can be treated with certainty in any of the currently recognized sections of Anisotes. Data pertinent to the conservation status of each species are provided

Population modelling and genetics of a critically endangered Madagascan palm Tahina spectabilis.

Madagascar is home to 208 indigenous palm species, almost all of them endemic and >80% of which are endangered. We undertook complete population census and sampling for genetic analysis of a relatively recently discovered giant fan palm, the Critically Endangered Tahina spectablis in 2008 and 2016. Our 2016 study included newly discovered populations and added to our genetic study. We incorporated these new populations into species distribution niche model (SDM) and projected these onto maps of the region. We developed population matrix models based on observed demographic data to model population change and predict the species vulnerability to extinction by undertaking population viability analysis (PVA). We investigated the potential conservation value of reintroduced planted populations within the species potential suitable habitat. We found that the population studied in 2008 had grown in size due to seedling regeneration but had declined in the number of reproductively mature plants, and we were able to estimate that the species reproduces and dies after approximately 70 years. Our models suggest that if the habitat where it resides continues to be protected the species is unlikely to go extinct due to inherent population decline and that it will likely experience significant population growth after approximately 80 years due to the reproductive and life cycle attributes of the species. The newly discovered populations contain more genetic diversity than the first discovered southern population which is genetically depauperate. The species appears to demonstrate a pattern of dispersal leading to isolated founder plants which may eventually lead to population development depending on local establishment opportunities. The conservation efforts currently put in place including the reintroduction of plants within the species potential suitable habitat if maintained are thought likely to enable the species to sustain itself but it remains vulnerable to anthropogenic impacts

Repeatedly Northwards and Upwards: Southern African Grasslands Fuel the Colonization of the African Sky Islands in Helichrysum (Compositae)

The Afromontane and Afroalpine areas constitute some of the main biodiversity hotspots of Africa. They are particularly rich in plant endemics, but the biogeographic origins and evolutionary processes leading to this outstanding diversity are poorly understood. We performed phylogenomic and biogeographic analyses of one of the most species-rich plant genera in these mountains, Helichrysum (Compositae-Gnaphalieae). Most previous studies have focused on Afroalpine elements of Eurasian origin, and the southern African origin of Helichrysum provides an interesting counterexample. We obtained a comprehensive nuclear dataset from 304 species (≈50% of the genus) using target-enrichment with the Compositae1061 probe set. Summary-coalescent and concatenation approaches combined with paralog recovery yielded congruent, well-resolved phylogenies. Ancestral range estimations revealed that Helichrysum originated in arid southern Africa, whereas the southern African grasslands were the source of most lineages that dispersed within and outside Africa. Colonization of the tropical Afromontane and Afroalpine areas occurred repeatedly throughout the Miocene-Pliocene. This timing coincides with mountain uplift and the onset of glacial cycles, which together may have facilitated both speciation and intermountain gene flow, contributing to the evolution of the Afroalpine flora.This work received financial support from the Spanish Ministry of Science, Innovation and Universities (PID2019-105583GB-C22/AEI/10.13039/501100011033) and the Catalan government (“Ajuts a grups consolidats” 2021SGR00315 and FI grant to C.B.-G. 2022FI_B 00150). The Ph.D. thesis was carried out under the Ph.D. program “Plant Biology and Biotechnology” of the Autonomous University of Barcelona (UAB). Additional support was provided by the Czech Science Foundation GAČR project no. 20-10878S to R.S. and F.K. and long-term research development project (RVO 67985939) of the Czech Academy of Sciences. Additional funds were obtained from the Norwegian Programme for Development, Research and Higher Education (NUFU; project AFROALP-II, no 2007/1058) and the Research Council of Norway (project SpeciationClock, no 274607) to C.B.Abstract 1. Introduction 2. Materials and Methods 2.1. Taxon Sampling 2.2. DNA Extraction, Library Preparation, Target Capture, and Sequencing 2.3. Molecular Data Processing and Phylogenetic Analyses 2.4. Divergence Time Estimation 2.5. Ancestral Range Estimation 3. Results 3.1. Alignment Processing and Filtering 3.2. Phylogenetic Analyses 3.3. Divergence Time and Ancestral Range Estimation 3.4. Number, Type, and Directionality Estimation of Biogeographical Events 4. Discussion 4.1. Utility of Target-Enrichment Strategies in Reconstructing the Radiation of Helichrysum 4.2. The Early History of Helichrysum and Colonization of Madagascar 4.3. Repeatedly Northwards 4.4. Repeatedly Upwards 5. Conclusions Supplementary Materials Author Contributions Funding Data Availability Statement Acknowledgments Conflicts of Interest Reference