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981.
William Buckland not only was an eccentric scientist either liked or disliked by his peers but, in the early 1800s, was also the foremost authority on coprolites. The latter were a source of considerable amusement to some of his friends. 相似文献
982.
Gerald Mayr 《Journal of Ornithology》1998,139(2):121-129
Zusammenfassung Ein Vogel aus dem Mittel-Eozän der Grube Messel (Hessen, Deutschland) wird als neue Gattung und Art der Archaeotrogonidae Mourer-Chauviré 1980 beschrieben (incertae sedis). Die Exemplare aus Messel wären die ersten artikulierten Skelette dieser Familie.Hassiavis laticauda n. gen. n. sp. unterscheidet sich vor allem im Bau des Coracoids von der GattungArchaeotrogon Milne-Edwards 1892. Besonders bemerkenswert ist die ausgezeichnete Erhaltung der Flügel- und Schwanzbefiederung einiger Exemplare. Einige Schwanzfedern des Holotypus zeigen eine Querbänderung, welche möglicherweise auf die ursprüngliche Pigmentierung dieser Federn zurückzuführen ist. Die phylogenetische Stellung der Archaeotrogonidae wird diskutiert. Zur Zeit sind keine Synapomorphien bekannt, welche diese Familie mit einer der bestehenden Ordnungen verbinden.
An Archaeotrogon (Aves: Archaeotrogonidae) from the Middle Eocene of the Grube Messel (Hessen, Germany)?
Summary A bird from the Middle Eocene of the Grube Messel (Hessen, Deutschland) is described as a new genus and species of the Archaeotrogonidae Mourer-Chauviré 1980 (incertae sedis). The specimens from Messel would be the first articulated skeletons of this family.Hassiavis laticauda n. gen. n. sp. is distinguished from the genusArchaeotrogon Milne-Edwards 1892 in the morphology of the coracoid. The excellent preservation of the wing feathers and those of the tail in several of the specimens is exceptional. Some tail feathers of the holotype are barred, which might be traced back to the original pigmentation of these feathers. The phylogenetic position of the Archaeotrogonidae is discussed. At present no synapomorphies are known, which could set up a closer relationship between this family and one of the existing orders.相似文献
983.
Martin G. Lockley 《Ichnos》2013,20(2):155-159
Professional amateurs and amateur professionals 相似文献
984.
Didier Casane Patrick Laurenti 《BioEssays : news and reviews in molecular, cellular and developmental biology》2013,35(4):332-338
A series of recent studies on extant coelacanths has emphasised the slow rate of molecular and morphological evolution in these species. These studies were based on the assumption that a coelacanth is a ‘living fossil’ that has shown little morphological change since the Devonian, and they proposed a causal link between low molecular evolutionary rate and morphological stasis. Here, we have examined the available molecular and morphological data and show that: (i) low intra‐specific molecular diversity does not imply low mutation rate, (ii) studies not showing low substitution rates in coelacanth are often neglected, (iii) the morphological stability of coelacanths is not supported by paleontological evidence. We recall that intra‐species levels of molecular diversity, inter‐species genome divergence rates and morphological divergence rates are under different constraints and they are not necessarily correlated. Finally, we emphasise that concepts such as ‘living fossil’, ‘basal lineage’, or ‘primitive extant species’ do not make sense from a tree‐thinking perspective. Editor's suggested further reading in BioEssays Tree thinking for all biology: the problem with reading phylogenies as ladders of progress Abstract 相似文献
985.
986.
《Saudi Journal of Biological Sciences》2023,30(9):103742
Cadmium (Cd) is a pollutant that poses a health risk for humans and animals. Coral fossil (CF) acts as an adsorbent, yet limited knowledge is available on impacts of CF on Cd toxicities. The work was performed to figure out the effects of CF on hematobiochemical details and specific organs in Cd exposed broilers. The experiment was carried out with 45 broilers and were divided into three groups (15 in each). Group A was served as control. The birds in group B received Cd (75 mg /kg b. w.) orally. Whereas group C was orally supplemented with Cd (75 mg /kg b. w.) and CF (1 gm/kg b. w.). The trial was lasted for 30 days. For hematobiochemical analysis, blood samples were drawn, and sera were separated. Liver, kidney and muscle were collected to assess accumulation concentration. Brain, liver and kidney samples were also collected for histopathological study. The results showed that hematological parameters (TEC, Hb, PCV, MCV, MCH, MCHC and DLC) were altered by Cd but restored with CF supplementation. Liver (AST, ALT and ALP) and kidney (total protein and creatinine) biomarkers were increased significantly in Cd treated broilers while decreased significantly after CF supplementation. CF reduced accumulation concentration of Cd in liver, kidney and muscle. Cd intoxicated broilers showed degenerative changes in brain, hyperplastic bile duct and proliferation of renal tubular epithelium with focal degeneration and necrosis; and these were improved after CF supplementation. Therefore, it can be concluded that CF is a potential adsorbent against Cd toxicities. 相似文献
987.
We describe a partial skeleton of a fossil owl (Strigiformes) from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK). The holotype of Ypresiglaux michaeldanielsi, gen. et sp. nov. is one of the most complete specimens of a Palaeogene owl and elucidates the poorly known ecomorphology of stem group Strigiformes. Whereas most of the postcranial bones show the characteristic strigiform morphology, the new species exhibits plesiomorphic features of the skull and cervical vertebrae that differ distinctly from extant owls. A well-developed supraorbital process of the lacrimal bone suggests that the eyes were not as greatly enlarged and forward-facing as in extant owls. A plesiomorphic quadrate morphology indicates differences in the otic region, and a proportionally longer axis suggests that the fossil species was not able to rotate its head to the degree found in crown group Strigiformes. Therefore, the fossil documents a mosaic evolution of the strigiform body plan, with owls developing raptorial adaptations before specializations of the visual and acoustic systems evolved. Because the latter relate to a crespuscular or nocturnal activity pattern, we hypothesize that Ypresiglaux was diurnal. Nocturnality in owls may have evolved in response to the emergence of evolutionary opportunities, which enabled owls to exploit new ecological niches, or owls may have been driven into nocturnal habits by ecological competition. 相似文献
988.
989.
Andrei A. Legalov 《Insect Science》2012,19(6):683-698
Abstract The first synopsis of Mesozoic weevils (Curculionoidea: Coleoptera) is presented. Changes of family, genera and species abundance during the Mesozoic revealed three distributional patterns. The Jurassic (Karatau) fauna was dominated by the Nemonychidae. During the Early Cretaceous (beginning at the Jurassic/Cretaceous border), the Ithyceridae was the prevalent group with a significant role played by the Nemonychidae. In the Late Cretaceous (Cenomanian and Turonian), the major groups were the Curculionidae and Brentidae. Obviously, the change of weevil fauna during this period was due to the expansion of the angiosperms, which provided multiple niches in their vegetative and reproductive organs for weevil development. 相似文献
990.
The ichnospecies Cladichnus parallelum consists of upper components characterized by downward branching, decreasingly inclined tubes, and lower components having horizontal, long, parallel tubes formed in the laminated part of a muddy, marly turbidite. The tubes of both components were successively produced, and the lower ones display an annulated fill. The producers of Cladichnus exhibit thigmotactic and phobotactic behavior in that the tubes are regularly spaced apart, do not cross over- or cross-cut, and their orientation is related to the fabric of the turbidite. The tube fill of both components is enriched in terrigenous material and organic matter suggesting selective feeding on the sediment surface, and the tubes do not show any grain sorting around them. The strong compression of the horizontal tubes suggests that the fill initially had high porosity. The producer of Cladichnus parallelum probably took advantage of burrowing in an anoxic setting; microbes likely played a role in converting organic material stored within the tubes or in processing dissolved compounds drained into the highly porous tubes. 相似文献