scholarly journals A unique flower in Miocene amber sheds new light on the evolution of flowers

2020 ◽  
Vol 3 (4) ◽  
pp. 423-432
Author(s):  
XUE-DIE LIU ◽  
JOSÉ BIENVENIDO DIEZ ◽  
YONG FAN ◽  
ZHONG-JIAN LIU ◽  
XIN WANG
Keyword(s):  
Genetic Evidence ◽  
Bisexual Flower ◽  
Dominican Amber ◽  
Fossil Evidence ◽  
Evolutionary Science ◽  
Flower Evolution

The evolution of flowers is among the foremost topics in evolutionary science. The question for botanists of how flowers evolved exists mainly due to lack of relevant fossil evidence, especially of well-preserved flowers. Dominican amber has yielded abundant fossils (including those of flowers) and thus opens a unique window on flower evolution. Here we report a unique flower preserved in mid-Miocene Dominican amber, Dinganthus pentamera gen. et sp. nov. The flower is actinomorphic, pentamerous, bisexual flower including two bracts, five tepals, 10 stamens, and gynoecium. The stamens are dorsifixed, filamentous, and latrorse. The gynoecium in the centre comprises three portions, namely, a basal gynophore, multiple ovaries in the middle, and an apical style. Supplementing to the developmental and genetic evidence, the unique morphology of Dinganthus suggests that a flower is a condensed shoot with lateral appendages, a long-held belief in botany.

scholarly journals Using hominin introgression to trace modern human dispersals

2019 ◽  
Vol 116 (31) ◽  
pp. 15327-15332 ◽  
Author(s):  
João C. Teixeira ◽  
Alan Cooper
Keyword(s):  
New Guinea ◽  
Modern Human ◽  
Genetic Evidence ◽  
Human Populations ◽  
Before Present ◽  
Archaeological Evidence ◽  
Fossil Evidence ◽  
The World ◽  
Out Of Africa ◽  
Wallace’S Line

The dispersal of anatomically modern human populations out of Africa and across much of the rest of the world around 55 to 50 thousand years before present (ka) is recorded genetically by the multiple hominin groups they met and interbred with along the way, including the Neandertals and Denisovans. The signatures of these introgression events remain preserved in the genomes of modern-day populations, and provide a powerful record of the sequence and timing of these early migrations, with Asia proving a particularly complex area. At least 3 different hominin groups appear to have been involved in Asia, of which only the Denisovans are currently known. Several interbreeding events are inferred to have taken place east of Wallace’s Line, consistent with archaeological evidence of widespread and early hominin presence in the area. However, archaeological and fossil evidence indicates archaic hominins had not spread as far as the Sahul continent (New Guinea, Australia, and Tasmania), where recent genetic evidence remains enigmatic.

Fossil actinomycete in Eocene-Oligocene Dominican amber

1994 ◽  
Vol 68 (2) ◽  
pp. 398-401 ◽  
Author(s):  
Benjamin M. Waggoner
Keyword(s):  
South Africa ◽  
Late Pleistocene ◽  
Early Cretaceous ◽  
Plant Roots ◽  
Gram Positive ◽  
Lower Carboniferous ◽  
Bed Sediments ◽  
Dominican Amber ◽  
Fossil Evidence ◽  
Actinorhizal Nodules

Actinomycetes are Gram-positive prokaryotes that tend to form branching and fragmenting filaments, which in some groups form a sizable mycelium. They make up a large and important part of modern terrestrial microfloras but are not known extensively as fossils, although they have a long fossil history. Actinomycete-like fossils appear several times in the Precambrian: in the middle Precambrian Gowganda Formation of Ontario (Jackson, 1967), in the 2.0 Ga Gunflint Chert of Ontario (Lanier, 1987), and possibly in a lichen-like symbiosis in the 2.8 Ga Witwatersrand rocks of South Africa (Hallbauer and Van Warmelo, 1974), among others. Direct fossil evidence of actinomycetes is very rare in the Phanerozoic, and some “fossil” actinomycetes may be later contaminants (Knoll, 1977; Smoot and Taylor, 1983). Hyphae identified as actinomycetes are known from rod-like bodies identified as nematodes inside a decaying scorpion from the lower Carboniferous of Scotland (Stoermer, 1964), and from the interior of fern phloem cells from the Pennsylvanian (Smoot and Taylor, 1983). Unmineralized Actinomyces-like cells are known from calcite in bituminous lake-bed sediments from the early Cretaceous of Nevada (Bradley, 1963), and similar, poorly preserved fossils of a form called Actinomycites have been reported from the Jurassic of Scotland (Ellis, 1915). Actinorhizal nodules, formed by actinomycetes symbiotic with plant roots, have been described from the late Pleistocene (Baker and Miller, 1980).

A fossil Aspergillus from Eocene Dominican amber

1988 ◽  
Vol 62 (01) ◽  
pp. 141-143 ◽  
Author(s):  
Gerard M. Thomas ◽  
George O. Poinar
Keyword(s):  
Dominican Republic ◽  
Fossil Species ◽  
First Report ◽  
Dominican Amber ◽  
Eocene Amber

A sporulating Aspergillus is described from a piece of Eocene amber originating from the Dominican Republic. The Aspergillus most closely resembles a form of the white spored phase of Aspergillus janus Raper and Thom. This is the first report of a fossil species of Aspergillus.

Robert E. Grant's later views on organic development: the Swiney lectures on “Palaeozoology”, 1853–1857

1984 ◽  
Vol 11 (3) ◽  
pp. 395-413 ◽  
Author(s):  
ADRIAN DESMOND
Keyword(s):  
Steady State ◽  
Development Theory ◽  
Fossil Evidence

SUMMARY R. E. Grant's advocacy of transmutation is considered in relation to the scientific climate of the 1850s. To understand the palaeontological framework of his development theory, the unpublished “Palaeozoology” lectures, delivered in 1853–7, are analysed and his sources tabulated. The lectures are shown to contain the following additional themes: (1) a refutation of Lyell's steady-state geology, (2) support for serial development, (3) use of metamorphic effacement to explain the lack of pre-Silurian fossils, and (4) nebular hypothesis. The difficulty of supporting serial development using fossil evidence at this late date is discussed, and this difficulty is deemed to have contributed to the failure of Grant's theory of species “generation”.

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