Sterile foliage of fertile Sydneia manleyi and synangial chemistry (eusporangiate fern, Late Asturian, Canada): A new subfamily Sydneideae

Typification of Sydneia manleyi Psenicka et al. 2003 is based entirely on fertile foliage. Of late,attached sterile-fertile segments have been found which are illustrated and described, together with cuticular preparations. A new subfamily, Sydneideae subfam. nov. is erected for the monotypytic species. The synangial chemistry is compared with marattialean  synangia/sporangia from the Czech Republic and from Canada.Fil: Psenicka, Josef. West Bohemian Museum in Pilsen. Palaeontological Department; República ChecaFil: Zodrow, Erwin L.. Cape Breton Universit. Palaeobiology Laboratory; CanadáFil: D` Angelo, José Alejandro. Cape Breton Universit. Palaeobiology Laboratory; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

3D chemometric model simulating the Acitheca polymorpha frond: implications for reconstructing carboniferous ferns (Marattiales, Canada)

Reported are results of an initial approximate imitation of a Carboniferous fern frond, i.e., marattialean Acitheca polymorpha (Schimper), Middle Pennsylvanian Sydney Coalfield, Canada. The simulation experiment is based on the analysis of 14 infrared spectra obtained by means of Fourier Transform Infrared spectroscopy from four detached fragments of sterile polymorphic penultimate-pinna compressions. The calculated relative, semi-quantitative, chemical data from the infrared spectra are the input for principal component analysis deriving a 3D (three-dimensional) chemometric model. To interpret it, the four specimens are placed in hypothetical-frond positions simulating a tripinnate frond, based on diminishing penultimate-rachial widths from 1-mm (distal) to 10-mm (proximal). Hypothetical conclusions include position-dependent chemistries, specifically that of opposing trends of aromaticity vs. aliphaticity in pinnules-rachises. This, in turn, would suggest potential for (i) fern-frond reconstruction, and (ii) for determination of a most likely frond position of fragmentary specimens by “chemical classification”; the predictive aspect. However, further experimental refinement is necessary particularly based on larger frond segments to confirm or disconfirm the overall hypothetical results.Fil: D`angelo, José Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Cape Breton University; CanadáFil: Zodrow, Erwin L.. Cape Breton University; CanadáFil: Psenicka, Josef. West Bohemian Museum ; República Chec

Ancient vertebrate dermal armor evolved from trunk neural crest

Bone is an evolutionary novelty of vertebrates, likely to have first emerged as part of ancestral dermal armor that consisted of osteogenic and odontogenic components. Whether these early vertebrate structures arose from mesoderm or neural crest cells has been a matter of considerable debate. To examine the developmental origin of the bony part of the dermal armor, we have performed in vivo lineage tracing in the sterlet sturgeon, a representative of nonteleost ray- finned fish that has retained an extensive postcranial dermal skeleton. The results definitively show that sterlet trunk neural crest cells give rise to osteoblasts of the scutes. Transcriptional profiling further reveals neural crest gene signature in sterlet scutes as well as bichir scales. Finally, histological and microCT analyses of ray- finned fish dermal armor show that their scales and scutes are formed by bone, dentin, and hypermineralized covering tissues, in various combinations, that resemble those of the first armored vertebrates. Taken together, our results support a primitive skeletogenic role for the neural crest along the entire body axis, that was later progressively restricted to the cranial region during vertebrate evolution. Thus, the neural crest was a crucial evolutionary innovation driving the origin and diversification of dermal armor along the entire body axis.</p