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Zamia multidentata is described and illustrated here as a new species from the Amazon basin, state of Acre, Brazil. The new species shares morphological similarities with the Amazonian species Z. hymenophyllidia, and Z. urep, to which it is compared. The combination of slender (to 6.2 cm) caulescent stems, strongly serrulate elliptic leaflets with long acuminate tips and a pronounced adaxially raised longitudinal crease, as well as seed strobili with long peduncles (15 cm +) and flat megasporophylls distinguish the new species Zamia multidentata from all other known species in the genus.
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Zamia magnifica (Zamiaceae, Cycadales): A New Rupicolous Cycad Species from Sierra Norte, Oaxaca, Mexico
Zamia magnifica (Zamiaceae), a new species endemic to Sierra Norte, Oaxaca, Mexico, is described. Zamia magnifica is characterized by having a rupicolous habit, pendent leaves bearing leaflets that are densely tomentose and pink to caramel in color when emerging, and broad oblong leaflets that are coriaceous in texture with few non-prominent denticulations and ovulate strobili with short (<4 cm) peduncles. It is compared to Z. furfuracea and Z. meermanii, the Mesoamerican Zamia species to which it shares the closest morphological resemblance.
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- Award ID(s):
- 2140319
- PAR ID:
- 10417836
- Date Published:
- Journal Name:
- Taxonomy
- Volume:
- 3
- Issue:
- 2
- ISSN:
- 2673-6500
- Page Range / eLocation ID:
- 232 to 249
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Zamia orinoquiensis Calonje, Betancur & A.Lindstr., a new species from the western Orinoquía region of Colombia is described and illustrated. The species is segregated from and compared to Z. muricata Willd., the latter which is morphologically recharacterized, illustrated, and recircumscribed to include populations from tropical dry forest and tropical moist forests in the Lara-Falcón Formation and the Cordillera de la Costa natural regions of Venezuela, as well as the Serranía de Macuira in La Guajira, Colombia. Zamia orinoquiensis is morphologically distinguished from Z. muricata by its leaves bearing fewer, coriaceous (vs. papyraceous) leaflets, eophylls with 2 (vs. 4) leaflets, pollen strobili that are brown to reddish brown (vs. cream to tan) with larger microsporophylls bearing more numerous microsporangia, and ovulate strobili that are dark brown to black (vs. dark olive green to olive brown) at maturity.more » « less
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null (Ed.)Coevolution between plants and insects is thought to be responsible for generating biodiversity. Extensive research has focused largely on antagonistic herbivorous relationships, but mutualistic pollination systems also likely contribute to diversification. Here we describe an example of chemically-mediated mutualistic species interactions affecting trait evolution and lineage diversification. We show that volatile compounds produced by closely related species of Zamia cycads are more strikingly different from each other than are other phenotypic characters, and that two distantly related pollinating weevil species have specialized responses only to volatiles from their specific host Zamia species. Plant transcriptomes show that approximately a fifth of genes related to volatile production are evolving under positive selection, but we find no differences in the relative proportion of genes under positive selection in different categories. The importance of phenotypic divergence coupled with chemical communication for the maintenance of this obligate mutualism highlights chemical signaling as a key mechanism of coevolution between cycads and their weevil pollinators.more » « less
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null (Ed.)The plasma membrane of eukaryotic cells is known to be compositionally asymmetric. Certain phospholipids, such as sphingomyelin and phosphatidylcholine species, are predominantly localized in the outer leaflet, while phosphatidylethanolamine and phosphatidylserine species primarily reside in the inner leaflet. While phospholipid asymmetry between the membrane leaflets is well established, there is no consensus about cholesterol distribution between the two leaflets. We have performed a systematic study, via molecular simulations, of how the spatial distribution of cholesterol molecules in different “asymmetric” lipid bilayers are affected by the lipids’ backbone, head-type, unsaturation, and chain-length by considering an asymmetric bilayer mimicking the plasma membrane lipids of red blood cells, as well as seventeen other asymmetric bilayers comprising of different lipid types. Our results reveal that the distribution of cholesterol in the leaflets is solely a function of the extent of ordering of the lipids within the leaflets. The ratio of the amount of cholesterol matches the ratio of lipid order in the two leaflets, thus providing a quantitative relationship between the two. These results are understood by the observation that asymmetric bilayers with equimolar amount of lipids in the two leaflets develop tensile and compressive stresses due to differences in the extent of lipid order. These stresses are alleviated by the transfer of cholesterol from the leaflet in compressive stress to the one in tensile stress. These findings are important in understanding the biology of the cell membrane, especially with regard to the composition of the membrane leaflets.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/taxonomy3020017
