| 1. |
-
The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data
- 2022
-
Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2
-
Tidskriftsartikel (refereegranskat)abstract
- This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
|
|
| 2. |
- Friis, Else Marie, et al.
(författare)
-
Early and Mid-Cretaceous Aristolochiaceous Seeds from Portugal and Eastern North America
- 2022
-
Ingår i: International journal of plant sciences. - Chicago : University of Chicago Press. - 1058-5893 .- 1537-5315. ; 183:7, s. 587-603
-
Tidskriftsartikel (refereegranskat)abstract
- Premise of research. The fossil record of Aristolochiaceae (Piperales, magnoliids) is sparse, particularly from Cretaceous strata. Fossil seeds from the Early and mid-Cretaceous of Portugal and North America provide the earliest unequivocal documentation of the group.Methodology. Detailed morphological and anatomical investigations of the fossil aristolochiaceous seeds were carried out using SEM and synchrotron radiation X-ray tomographic microscopy (SRXTM). Comparison with other seeds, extinct as well as extant, was based on published data and SRXTM analyses.Pivotal results. Two new genera and two new species, Aristospermum huberi and Siratospermum mauldinense, are described based on fossil seeds from the Early and mid-Cretaceous of Portugal and North America. The seeds are anatropous and bitegmic, with the micropyle formed by the inner integument. The testa consists of an exotesta of varied thickness and an endotesta of crystalliferous cells. The tegmen is three cell layers thick and consists of an outermost layer of longitudinally aligned fibers, a middle layer of transversely aligned fibers perpendicular to the longitudinal fibers, and an inner layer of thin-walled cuboidal cells. In most seeds the exotesta is abraded, exposing the crystalliferous cells of the endotesta. Among extant plants, a similar seed coat with a crystalliferous endotesta and crossing fibers in the tegmen is unique to Aristolochiaceae.Conclusion. The unique seed coat allows Aristospermum and Siratospermum to be assigned confidently to the lineage that today includes extant Aristolochiaceae. Aristospermum and Siratospermum provide the first unequivocal documentation of the Aristolochiaceae lineage of the Piperales during the Early Cretaceous diversification of angiosperms.
|
|
| 3. |
- Friis, Else Marie, et al.
(författare)
-
Extinct seed plant diversity in the Early Cretaceous: An enigmatic new microsporangiate fossil with Decussosporites pollen in situ
- 2022
-
Ingår i: Review of Palaeobotany and Palynology. - Amsterdam : Elsevier. - 0034-6667 .- 1879-0615. ; 304, s. 104716-104716
-
Tidskriftsartikel (refereegranskat)abstract
- A new microsporangiate cone, Renbernia zhoui, is described from the mesofossil flora extracted from exposures ofthe Potomac Group at Puddledock, Virginia, U.S.A., which are of Early Cretaceous (early-middle Albian) age. The cone consists of densely arranged dorsiventrally flattened laminar, flabelliform microsporangiophores that bear two elongate microsporangia on the presumed abaxial surface. The microsporangia are separated by sterile tissue that expands apically into a prominent hood-like sterile extension. The microsporangia have extrorse valvate dehiscence and both microsporangia and sterile apical expansion are covered by a short stiff hairs. In situ pollen resembles Decussosporites, elliptical with a long median colpus on the presumed distal surface flanked laterally by two equally long lateral colpi. A short transverse colpus on the presumed proximal surface links the two lateral colpi and divides the grain into two parts creating the appearance of two sacci. Renbernia zhoui is similar to Brenneria potomacensis described from the slightly older Drewry's Bluff and Dutch Gap mesofossil floras from the Potomac Group that also has Decussosporites-type pollen in situ. However, Renbernia microsporangiophores are more distinctly laminar and have sporangia that are more prominently elongated and with a hood-like apical extension of sterile tissue. The in situ pollen is also much smaller, the pollen wall is much more distinctly perforate-foveolate rather than more or less psilate, and in Renbernia the saccus-like structures are not inflated. The relationship of Brenneria and Renbernia, as well as the possible link between Decussosporites-type pollen and pollen of Eucommiidites (Erdtmanithecales) is discussed.
|
|
| 4. |
- Friis, Else Marie, et al.
(författare)
-
The Early Cretaceous mesofossil flora of Catefica, Portugal: angiosperms
- 2022
-
Ingår i: Fossil Imprint. - Prague : National Museum. - 2533-4050 .- 2533-4069. ; 78:2, s. 341-424
-
Tidskriftsartikel (refereegranskat)abstract
- Angiosperm mesofossils are described from the Lower Cretaceous Almargem Formation exposed near the village of Catefica, Portugal, and are thought to be of Aptian-early Albian age. The mesofossil assemblage from Catefica is diverse and, in addition to the angiosperms described here, also contains a rich assemblage of non-angiosperm fossils, including leafy axes of bryophytes and lycopsids, lycopsid and salvinialean megaspores, and sporangia, sori and leaf fragments of ferns. Thereare also twigs, cones, cone scales, seeds and sporangia of several kinds of conifers. Other seed plants include 11 species of chlamydospermous seeds and vegetative axes related to the BEG group (Bennettiales-Erdtmanithecales-Gnetales). In terms of the number of plant fragments identified, angiosperms are most abundant in the Catefica assemblage and account for morethan half of all specimens. Angiosperms also dominate in number of species, but because the non-angiosperm fossils have notbeen studied in detail the total number of species in the flora is not yet established. Sixty-seven species of angiosperms arerecognized. Angiosperm diversity is mainly at the level of non-eudicots, including ANA-grade angiosperms, Chloranthaceae and magnoliids. Remains of chloranthoid angiosperms are especially common, both in the number of specimens and in numberof species recognized. About 40 % of the specimens, and more than 25 % of the species are chloranthoids. Remains of magnoliid angiosperms (Magnoliales, Laurales, Canellales, Piperales) are also prominent among the angiosperms. Eudicots are subordinate: only 3–4 % of all angiosperm specimens can be assigned confidently to eudicot angiosperms. Five new genera and six new species of angiosperms are established (Canrightia foveolata sp. nov., Elasmostemon paisii gen. et sp. nov., Endressistemon cateficensis gen. et sp. nov., Ibericarpus cuneiformis gen. et sp. nov., Proencistemon portugallicus gen. et sp. nov., Valvidistemon globiferus gen. et sp. nov.). Several other new taxa are also described, but not formally named.
|
|
