Molecular systematics studies, new species descriptions, developmental genetics of seeds, land plant phylogenomics, the description of a 125 million year old tree fern fossil–this, and more, is the research of the scientists at The New York Botanical Garden.
Frontiers for young minds: What is a fruit?
This wonderful, kid-friendly article resulted from a science internship project in our research laboratory. The article explains the botanical concepts surrounding fruits, i.e., what they are, how they develop, and how they vary.
If you have ever been inside a grocery store, you have probably noticed the produce section. Mountains of lemons, piles of tomatoes, rows of cucumbers, several kinds of apples, and more. Some of these items you might know as fruits, and others as vegetables. But what is the difference between a fruit and a vegetable? When you eat an apple, strawberry, or peach, what part of the plant are you eating? This article explores our knowledge of fruits and how to properly identify them.
Frontiers for Young Minds: Science for kids, edited by kids, March 2020
(NYBG Contacts: Cecilia Zumajo, Barbara Ambrose)
Regional records improve data quality in determining plant extinction rates
This paper contributes to an ongoing discussion of plant extinction, as a critique of a recent study that purported to document the extinction of 600 plant species globally. In this response, the authors carefully scrutinize the North American data from the original analysis, which reported 38 extinct plant species in the United States and Canada.
Careful scrutiny of the North American data reveals that seven of the documented species are still extant, and seven of the species are not taxonomically distinct, thus appearing to reduce the number of North American extinctions from 38 to 24. However, the authors also note an additional 42 extinct taxa (28 species and 14 infraspecific taxa) that were overlooked in the original analysis, which brings the revised total for North America to 53 species (and 67 taxa). Therefore, based on North American data, the extinction rate is considerably greater for the United States and Canada than reported in the earlier study. The authors emphasize the importance of data quality, taxon concepts, inclusion of infraspecific taxa, and the taxonomic knowledge that is required to understand and document extinctions. These results suggest that careful scrutiny of global records will reveal similarly underestimated numbers of extinct species in other regions.
(Nature Ecology & Evolution, March 2020
NYBG Contact: Rob Naczi)
Nature Ecology & Evolution link
Neotropical Diversification: Patterns and Processes
This book provides a comprehensive overview of the patterns of biodiversity in neotropical ecosystems, as well as a discussion on their historical biogeographies and underlying diversification processes.
With chapters on the Amazon and Caribbean forests, the Atlantic rainforests, the Andes, the Cerrado savannahs, the Caatinga drylands, the Chaco, and Mesoamerica – along with broad taxonomic coverage – this book summarizes a wide range of hypotheses, views, and methods concerning the processes and mechanisms of neotropical diversification. The range of perspectives presented makes the book a truly comprehensive, state-of-the-art publication on the topic, which will fascinate both scientists and general readers alike.
*Two chapters in the book derive from NYBG’s ongoing participation in the Dimensions of Biodiversity: Brazilian Atlantic Forest research project, and one of these chapters (Reginato & Michelangeli) generates an assessment of bioregions in eastern Brazil based on digitized herbarium specimen data.
(Neotropical Diversification: Patterns and Processes, April 2020
NYBG Contact: Fabian Michelangeli)
*Peres, E. A., R. Pinto-da-Rocha, L. G. Lohmann, F. A. Michelangeli, C. Y. Miyaki & A. C. Carnaval. 2020. Patterns of Species and Lineage Diversity in the Atlantic Rainforest of Brazil. In: Rull V, Carnaval AC (eds.) Neotropical Diversification: Patterns and Processes. Springer International Publishing, Cham, pp 415-447. doi:10.1007/978-3-030-31167-4_16
*Reginato, M. & F. A. Michelangeli. 2020. Bioregions of Eastern Brazil, Based on Vascular Plant Occurrence Data. In: Rull V, Carnaval AC (eds.) Neotropical Diversification: Patterns and Processes. Springer International Publishing, Cham, pp 475-494. doi:10.1007/978-3-030-31167-4_18
Pollination of cycads in an urban environment
The authors address the poorly-researched topic of insect pollination in urban environments by looking at reproduction in two genera of Mexican cycads. Both of the cycad species studied–Ceratozamia tenuis and Dioon edule–and their pollinators, are native to Mexico but threatened by habitat loss.
The two species were planted in gardens within the city of Xalapa-Enríquez, a distinctly urban area located within the broad distribution ranges of both species. The authors found obligate insect pollinators, two different species of beetles, associated with the pollen and ovulate cones of both cycad species (one pollinator with each cycad species), suggesting the maintenance of ecological interactions as they occur in the wild. Details of this gymnosperm–beetle pollination system, which is somewhat unexpected in urban areas, offer some encouragement for the conservation of species threatened by habitat loss.
Botany, April, 2020
(NYBG Contact: Dennis Stevenson)
The influence of floral variation and geographic disjunction on the evolutionary dynamics of Ronnbergia and Wittmackia (Bromeliaceae: Bromelioideae)
In this study, the authors reconstructed the biogeographic history of two genera of bromeliads, Ronnbergia and Wittmackia, in the Brazilian Pacific Forest, the Atlantic Forest and the Caribbean.
The authors also compared the evolutionary rates and floral evolution in each of the areas for the two genera, which constitute the Ronnbergia alliance. The results suggested that the Ronnbergia alliance originated in the Atlantic Forest, followed by the origin of Ronnbergia after a long-distance dispersal event to the Pacific Forest. Wittmackia originated in the Atlantic Forest and later arrived to the Caribbean through a long-distance dispersal event to Jamaica. The authors suggest that the Caribbean is a much more dynamic area of diversification for the Ronnbergia alliance than the Atlantic Forest or the Pacific Forest.
Botanical Journal of the Linnean Society, April, 2020
(NYBG Contact: Fabián Michelangeli)
Phylogenetic analyses of key developmental genes provide insight into the complex evolution of seeds
In seed plants, there is much variation in the structure of the ovule. However, to date, most of our knowledge of the genetics of ovule development comes from studies of a single model species, the flowering plant Arabidopsis thaliana.
This comparative study allowed the authors to examine the genetic control ovule development across seed plants. The authors dissected the gene regulatory network involved in seed development and examined the evolutionary history of the gene lineages involved. Surprisingly, gene duplication is greater in the gymnosperms, which generally have a more simple (i.e., unitegmic) seed morphology. In addition, protein sequences indicate that ovule genes do not have similar roles across seed plants. This study provides a framework for molecular genetic analyses of non-model organisms.
Molecular Phylogenetics and Evolution, March 9, 2020
(NYBG Contacts: Cecilia Zumajo, Barbara Ambrose)
Miconia lucenae (Melastomataceae), a new species from montane Atlantic Forest in Espírito Santo, Brazil
The authors describe Miconia lucenae, a new species from the montane Atlantic Forest in Santa Teresa in the state of Espírito Santo, Brazil.
Based on a combination of plastid and nuclear loci, the new species is assigned to a small clade with Miconia paradoxa and M. michelangeliana. The three species in the “Paradoxa clade” can be recognized by a long list of (vegetative and reproductive) characters most readily appreciated by melastome specialists. The distinguishing features of the new species are concisely stated in the diagnosis: Miconia lucenae differs from Miconia paradoxa in having terete young branches (vs. strongly decussate-flattened in M. paradoxa), ciliate inner portion of the sepals (vs. eciliate), and lanceolate petals (vs. obovate). Miconia lucenae is endangered according to IUCN criteria.
Peer J, March 19, 2020
(NYBG Contact: Fabián Michelangeli)
Organellomic data sets confirm a cryptic consensus on (unrooted) land‐plant relationships and provide new insights into bryophyte molecular evolution
Phylogenetic trees of bryophytes provide important evolutionary context for land plants. However, published inferences of overall embryophyte relationships vary considerably.
In this article, the authors performed phylogenomic analyses of bryophytes and relatives using both mitochondrial and plastid gene data sets, and investigated bryophyte plastome evolution. They tested for changes in plastid genes of a mycoheterotrophic liverwort (Aneura mirabilis) and a putatively mycoheterotrophic moss (Buxbaumia), and compared 15 bryophyte plastomes for major structural rearrangements.
Overall land‐plant relationships conflict weakly across analyses, but relationships within mosses, liverworts, and hornworts are largely congruent with previous studies. Relaxed purifying selection affects multiple plastid genes in mycoheterotrophic Aneura but not Buxbaumia, which leads the authors to cast doubt on the mycoheterophic status of the latter. Plastid genome structure is nearly invariant across bryophytes, but the tufA locus, presumed lost in embryophytes, is unexpectedly retained in several mosses. Autotrophic bryophyte plastomes, including Buxbaumia, hardly vary in overall structure.
American Journal of Botany, January, 2020
(NYBG Contact: Dennis Stevenson)
A mid-Cretaceous tree fern of Thyrsopteridaceae (Cyatheales) preserved in Myanmar amber
An unusual tree fern trapped in mid-Cretaceous Myanmar amber is described as Thyrsopteris cretacea (Thyrsopteridaceae). The fossil most resembles T. elegans, a present-day species endemic to the Juan Fernández Islands, based on the characters of the lamina segments, sori, indusia, and sporangia.
Thyrsopteris cretacea is the first described mid-Cretaceous tree fern preserved in amber. It adds to the diversity previously ascribed to the Thyrsopteridaceae, which has been based on Eocene fossils, and it extends the fossil record of the family further back to the mid-Cretaceous. Most previous fossils of Thyrsopteridaceae have been from the Southern Hemisphere and are therefore considered Gondwanan. Thyrsopteris cretacea represents one of the few occurrences of the family in Laurasia.
Cretaceous Research, January, 2020
(NYBG Contact: Robbin Moran)
Communications Biology: Floral evolution and specialized pollination systems
In this article, the authors present a novel approach to the study of flower shape evolution through the integration of advanced imaging techniques (High-Resolution X-ray Computed Tomography), state-of-the-art landmark-based geometric morphometrics, and phylogenetic comparative methods.
They chose Merianieae (Melastomataceae) as the study system because the group is characterized by repeated independent shifts from an ancestral bee pollination syndrome to systems involving different vertebrate pollinators. In addition, all Merianieae have tubular anthers that are characteristic of highly-specialized buzz pollination. This study serves as a good test of more generalized hypotheses that have been used to explain increased evolutionary flexibility (evolvability) and evolutionary success. The authors suggest that modularity of flower structure, “may be key to the adaptive success of functionally specialized pollination systems by making flowers flexible (evolvable) for adaptation to changing selection regimes.”
Communications Biology, December 5, 2019
(NYBG Contact: Fabián Michelangeli