Calamitean Cones and Their In Situ Spores from the Pennsylvanian Limnic Basins of the Czech Republic.

This paper describes the in situ spores of the Calamospora type, macerated from sixty-one specimens of calamitean cones belonging to sixteen species of genera, such as the Palaeostachya, Macrostachya, Calamostachys, and Huttonia from the Pennsylvanian Czech Republic period, specifically from the Moscovian/Kasimovian ages (i.e., Duckmantian-Stephanian). The in situ spores were compared to twenty dispersed species of Calamospora. The majority of spores were microspores; however, some cones yielded both micro- and megaspores. Morphological variations of the in situ spores, including the diameter, labrum, contact area, ontogenetic stages, and secondary folds of the exine, are described, including their importance for the classification of calamospores. The relationships of Elaterites, Pteroretis, Vestispora, and some monopseudosaccate spores are discussed. All Paleozoic Calamospora-producing parent plants are summarized.

Silurian Climatic Zonation of Cryptospore, Trilete Spore and Plant Megafossils, with Emphasis on the Prídolí Epoch.

This paper describes dispersed cryptospores and trilete spores from tropical, temperate and cool climate belts within Prídolí and compares them with the land plant megafossil record. The palynology of earlier intervals in the Silurian are also reviewed. A common feature of the cryptospore and trilete spore records is that their number is surprisingly lowest in the tropical climatic belt and much higher in the temperate and especially in the cool latitude, and the highest number of cryptospore taxa occurring only in one belt is found in the cool belt while the highest number of trilete spore taxa that occurred only in one belt is recorded in the temperate belt. In general, based on the dispersed spore record, we can estimate that the plant assemblages of the tropical belt were dominated by rhyniophytes; trimerophytes probably prevailed over rhyniophytes in the temperate belt, and rhyniophytes again dominated within the cool belt.

Spore Evidence for the Origin of Isoetalean Lycopsids?

A new hypothesis about the origin of isoetalean lycopsids was proposed based on palynological data. The occurrence of three apical papillae on the proximal surfaces of miospores is a significant palynological feature that is clearly defined in both isoetalean and selaginellalean clades. Three apical papillae appeared for the first time within lower Silurian (Wenlockian ca. 430 My) and only in rhyniophytoid plants. Using this observation, we suggest that isoetalean lycopsids could have evolved directly from rhyniophytoids and not from protolepidodendralean lycopsids in the middle Devonian (Eifelian-Givetian) as previously suggested, because protolepidodendralean spores do not possess three apical papillae. Spores with three apical papillae, reported as dispersed as well as in situ, were recorded continuously from the lower Silurian (Wenlockian) through the Devonian, Carboniferous, Permian, Mesozoic to Cenozoic era and form a phylogenetically independent lineage.

Dynamics of Silurian Plants as Response to Climate Changes.

The most ancient macroscopic plants fossils are Early Silurian cooksonioid sporophytes from the volcanic islands of the peri-Gondwanan palaeoregion (the Barrandian area, Prague Basin, Czech Republic). However, available palynological, phylogenetic and geological evidence indicates that the history of plant terrestrialization is much longer and it is recently accepted that land floras, producing different types of spores, already were established in the Ordovician Period. Here we attempt to correlate Silurian floral development with environmental dynamics based on our data from the Prague Basin, but also to compile known data on a global scale. Spore-assemblage analysis clearly indicates a significant and almost exponential expansion of trilete-spore producing plants starting during the Wenlock Epoch, while cryptospore-producers, which dominated until the Telychian Age, were evolutionarily stagnate. Interestingly cryptospore vs. trilete-spore producers seem to react differentially to Silurian glaciations-trilete-spore producing plants react more sensitively to glacial cooling, showing a reduction in species numbers. Both our own and compiled data indicate highly terrestrialized, advanced Silurian land-plant assemblage/flora types with obviously great ability to resist different dry-land stress conditions. As previously suggested some authors, they seem to evolve on different palaeo continents into quite disjunct specific plant assemblages, certainly reflecting the different geological, geographical and climatic conditions to which they were subject.

Ancient noeggerathialean reveals the seed plant sister group diversified alongside the primary seed plant radiation.

Noeggerathiales are enigmatic plants that existed during Carboniferous and Permian times, ∼323 to 252 Mya. Although their morphology, diversity, and distribution are well known, their systematic affinity remained enigmatic because their anatomy was unknown. Here, we report from a 298-My-old volcanic ash deposit, an in situ, complete, anatomically preserved noeggerathialean. The plant resolves the group's affinity and places it in a key evolutionary position within the seed plant sister group. Paratingia wuhaia sp. nov. is a small tree producing gymnospermous wood with a crown of pinnate, compound megaphyllous leaves and fertile shoots each with Ω-shaped vascular bundles. The heterosporous (containing both microspores and megaspores), bisporangiate fertile shoots appear cylindrical and cone-like, but their bilateral vasculature demonstrates that they are complex, three-dimensional sporophylls, representing leaf homologs that are unique to Noeggerathiales. The combination of heterospory and gymnospermous wood confirms that Paratingia, and thus the Noeggerathiales, are progymnosperms. Progymnosperms constitute the seed plant stem group, and Paratingia extends their range 60 My, to the end of the Permian. Cladistic analysis resolves the position of the Noeggerathiales as the most derived members of a heterosporous progymnosperm clade that are the seed plant sister group, altering our understanding of the relationships within the seed plant stem lineage and the transition from pteridophytic spore-based reproduction to the seed. Permian Noeggerathiales show that the heterosporous progymnosperm sister group to seed plants diversified alongside the primary radiation of seed plants for ∼110 My, independently evolving sophisticated cone-like fertile organs from modified leaves.

Sporophytes of polysporangiate land plants from the early Silurian period may have been photosynthetically autonomous.

The colonization of land by vascular plants is an extremely important phase in Earth's life history. This key evolutionary process is thought to have begun during the Middle Cambrian 1 period and culminated in the Silurian/Early Devonian period (interval about 509-393 million years ago (Ma)), and is documented primarily by microfossils (that is, by dispersed spores, phytodebris including fragments of algae, tissues, sporangia and cuticles), tubes and rare megafossils 2 . A newly recognized fossil cooksonioid plant with in situ spores from the Barrandian area, Czech Republic, is of the highest importance because it represents extremely ancient megafossil evidence of land plant diploid generation: sporophytes (~432 Ma). The robust size of this plant places it among the largest known early polysporangiate land plants and it is probable that it attained adequate size for both aeration and effective photosynthetic competence. This would mean not only that sporophytes were photosynthetically autonomous but also that the they might have been able to sustain a relatively gametophyte-independent existence.

Lateral release in hallux valgus deformity: from anatomic study to surgical tip.

The important part of hallux valgus deformity operations, especially in the case of an incongruent joint, is the release of the soft tissue on the lateral side of the first metatarsophalangeal joint. The purpose of the present anatomic study was, with preparation of the lateral structures of the joint and lateral conjoined tendon, to provide a background for a surgical tip of the release of the joint for an additional metatarsal osteotomy. For the present study, we used 30 specimens (15 left and 15 right) from 19 cadavers at the Institute of Anatomy, First Faculty of Medicine, Charles Faculty (Prague, Czech Republic). Only specimens that met the criteria of hallux valgus were included in the present study. The technique was based on the incision of the lateral sesamoid ligament and partial tenotomy of the lateral conjoined tendon from the first interdigital web space. The release was done gradually with supination and abduction of the big toe to achieve the smallest size of the tenotomy. The median of the tenotomy size of the conjoined tendon was 6.5 (range 5 to 14) mm. The median size of the conjoined tendon in the frontal plane just ventral to the sesamoid bone was 10.6 (range 8 to 14) mm. The technique of the release, in which the big toe was abducted and supinated, can minimize the size of the lateral conjoined tendon release and can minimize the possibility of a postoperative deformity.

Paratingia wudensis sp. nov., a whole noeggerathialean plant preserved in an earliest Permian air fall tuff in Inner Mongolia, China.

Noeggerathiales are a little known group of Carboniferous and Permian plants of uncertain systematic position that have been variously considered to be ferns, sphenopsids, progymnosperms, or a separate group. These heterosporous plants carry adaxial sporangia on leaf-like or disk-shaped sporophylls that form cones. Leaves are pinnate with a rather stiff appearance, and pinnules can be attached in either two or four rows. In the present report, we present the top of a noeggerathialean plant with leaves and strobili attached, Paratingia wudensis Wang, Pfefferkorn et Bek sp. nov., from an earliest Permian volcanic ash fall tuff in Inner Mongolia. The excellent preservation allows the reconstruction of the whole plant, the complex three-dimensional leaves with anisophyllous pinnules, the heterosporous strobili, and the spores in situ. The homology of leaves and strobili can be elucidated and contributes to an understanding of the debated taxonomic position of Noeggerathiales. The "anisophyllous" leaves carry pinnules arranged in four rows. The strobili are bisporangiate and have disk-shaped sporophylls, each with one ring of 10-14 adaxial sporangia around the strobilus axis. Megaspores have an equatorial bulge. This new species expands the known diversity of Noeggerathiales. It grew in a peat-forming forest, thus changing earlier interpretations of the growth of noeggerathialean plants with anisophyllous pinnules.