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To date only two genera of cycad stems have been described from Cenozoic strata ( Bororoa and Menucoa ). We describe a new species of Wintucycas , Wintucycas beatrizae sp. nov. (Encephalartoideae), from the basal Palaeogene of Patagonia. The new species is based on anatomically preserved mature cycadalean stems which have been recovered from the Pichaihue Limestones (Neuquén Basin, Patagonia, Argentina). The new species is characterized by the presence of a columnar stem with an armor of persistent leaf bases, vascular bundles displaying an omega pattern, the absence of cataphylls, a wide pith with medullary vascular bundles, mucilage canals and idioblasts, a polyxylic vascular cylinder, inverted xylem, and manoxylic wood. The presence of W. beatrizae sp. nov. in the Pichaihue Limestones suggests warm climate conditions during the early Palaeogene in the Neuquén Basin, and also extends the range of this genus of Cycadales (Encephalartoideae) into the Cenozoic. [ABSTRACT FROM AUTHOR]

The Middle Jurassic deposits of the Shemshak Group and Hojedk Formation are widespread in north, central, and central east Iran. In this paper, the Hojedk Formation in South Kouchekali, southwestern Tabas city, central east Iran was studied for palaeobotany and stratigraphy. This formation contains well preserved plant macrofossils belonging to 43 species assigned to 24 genera of various orders such as Equisetales, Filicales, Bennettitales, Cycadales, Caytoniales, Ginkgoales and Pinales. One biozone and four subzones are recognized. The lower and the upper boundaries of this assemblage biozone are identified by the first and the last observed occurrences of Coniopteris hymenophylloides (Brongniart) Seward, 1900 and Klukia exilis (Phillips) Raciborski, 1890, respectively. According to the occurrences of these index species and Ptilophyllum harrisianum Kilpper, 1968 and Nilssonia macrophylla Jacob & Shukla, 1955, an early Middle Jurassic (Aalenian-Bajocian) age is considered for this assemblage biozone. Moreover, a comparative biostratigraphy for the Middle Jurassic of Iran is suggested. As a result, the Coniopteris hymenophylloides- Klukia exilis Assemblage biozone is proposed as a biozone widespread through the whole Iranian Plate. On the basis of the relative abundance of Filicales, Pinales, Cycadales, and Equisetales and of the high diversity and abundance of macrophyllous cycadophytes (eight species), a humid sub-tropical climate is suggested for this locality. In addition, floral gradient, correspondence analysis and similarity index were considered. Therefore, it is confirmed that a uniform palaeoclimate and vegetation cover occurred in Iran during the Middle Jurassic and that Iran was located within Vakhrameev's Euro-Sinian Region. [ABSTRACT FROM AUTHOR]

Palaeoboganium jurassicumgen. et sp. nov. is described from the Middle Jurassic Daohugou formation in northern China.Palaeoboganium jurassicumis the first fossil representative of the enigmatic family Boganiidae, currently known from Gondwanan localities in South Africa, Australia and New Caledonia. Based on a phylogenetic analysis of adult external characters,Palaeoboganiumis recovered as the sister group ofParacucujusSen Gupta & Crowson andMetacucujusEndrödy-Younga & Crowson (Paracucujinae), whose adults pollinate cycads in Australia and South Africa. Based on phylogenetic evidence this taxon is suggested to be a potential pollinator of Jurassic cycads. http://zoobank.org/urn:lsid:zoobank.org:pub:7EDB8295-5EF3-40ED-9A84-479AD23611AF [ABSTRACT FROM PUBLISHER]

Background: Even if they are considered the quintessential "living fossils", the fossil record of the extant genera of the Cycadales is quite poor, and only extends as far back as the Cenozoic. This lack of data represents a huge hindrance for the reconstruction of the recent history of this important group. Among extant genera, Bowenia (or cuticles resembling those of extant Bowenia) has been recorded in sediments from the Late Cretaceous and the Eocene of Australia, but its phylogenetic placement and the inference from molecular dating still imply a long ghost lineage for this genus. Results: We re-examine the fossil foliage Almargemia incrassata from the Lower Cretaceous Anfiteatro de Ticó Formation in Patagonia, Argentina, in the light of a comparative cuticular analysis of extant Zamiaceae. We identify important differences with the other member of the genus, viz. A. dentata, and bring to light some interesting characters shared exclusively between A. incrassata and extant Bowenia. We interpret our results to necessitate the erection of the new genus Eobowenia to accommodate the fossil leaf earlier assigned as Almargemia incrassata. We then perfom phylogenetic analyses, including the first combined morphological and molecular analysis of the Cycadales, that indicate that the newly erected genus could be related to extant Bowenia. Conclusion: Eobowenia incrassata could represent an important clue for the understanding of evolution and biogeography of the extant genus Bowenia, as the presence of Eobowenia in Patagonia is yet another piece of the biogeographic puzzle that links southern South America with Australasia. [ABSTRACT FROM AUTHOR]

Umkomasiaceans are the most commonly recorded components of Gondwanan Triassic floras but they are not represented subsequently in that region. Their diversity appears to have substantially declined prior to the Rhaetian. Lower and Middle Jurassic floras in Australia and elsewhere in Gondwana are strikingly different from those of the Triassic, comprising ferns, lycopods, conifers, cycads, and bennettitaleans. The fern Cladophlebis Brongniart 1849 emend. Seward 1894 dominated coal-forming paludal environments during the Middle Jurassic in Queensland and it is one of the most commonly preserved plants in the Eastern Gondwanan Jurassic. Ginkgoaleans were present in Eastern Gondwana until near the end-Triassic but were absent below ca 60°S palaeolatitude during the Early and Middle Jurassic. The type specimen of Dicroidium superbum (Shirley 1898) Townrow 1957 emend. nov. has been inaccurately represented in the published record. Consequently, many specimens belonging to the species have been incorrectly assigned to other umkomasiacean species. Misidentifications and considerably enlarged circumscriptions of some species have resulted in an erroneous and simplistic morpho-continuum concept supposedly linking umkomasiacean fronds. Several commonly occurring umkomasiacean species are re-assessed with particular attention to their type specimens, two of which are accurately figured here for the first time. This re-assessment, together with evidence from allied fructifications and wood, supports the view that umkomasiacean fronds belong to several genera. Most umkomasiacean lineages probably terminated prior to the Rhaetian; however, Zuberia Frenguelli 1943 emend. Artabe 1990 persisted to near the close of the Triassic. [ABSTRACT FROM AUTHOR]

Plant macrofossil remains of Becklesia Seward, 1895 emend. Watson and Cusack, 2005, a rare genus of extinct cycad, have been known for over a century from Great Britain and Libya. Historically the genus was poorly characterized leading to many fossil cycads that resembled Becklesia being placed in other genera including Cycadites and Paracycas . We describe here a new species, B. maulnyi sp. nov., from an exceptional and almost complete cycad specimen housed for two hundred years in the collections of the Musée Vert of Le Mans. The specimen comprises the apex of a stem bearing petiolate and pinnate leaves with thin and widely separated leaflets, which possess two prominent abaxial stomatal grooves that are characteristic of the genus Becklesia . We reassign three other French cycad fossils previously described under different generic names to Becklesia . Finally, we briefly discuss the geographical and stratigraphical implications of the genus and also consider presence of entire cycads in the fossil record. [ABSTRACT FROM AUTHOR]

New compression leaf material of Ceratozamia (Zamiaceae) has been recognised in the European Cenozoic. A leaflet of Ceratozamia floersheimensis (Engelhardt) Kvaček was recovered among unidentified material from the Oligocene of Trbovlje, former Trifail, Slovenia, housed in old collections of the Austrian Geological Survey, Vienna. It is similar in morphology and epidermal anatomy to other specimens previously studied from the lower Oligocene of Flörsheim, Germany and Budapest, Hungary. A fragmentary leaflet assigned to C. hofmannii Ettingsh. was recovered in the uppermost part of the Most Formation (Most Basin in North Bohemia, Czech Republic) and dated by magnetostratigraphy and cyclostratigraphy to CHRON C5Cn.3n, that is, the latest early Miocene. It yielded excellently preserved epidermal structures, permitting confirmation of the generic affinity and a more precise comparison with this lower Miocene species previously known from Austria (Münzenberg, Leoben Basin) and re-investigated earlier. Both the Oligocene and Miocene populations of Ceratozamia are based on isolated disarticulated leaflets matching some living representatives in the size and slender form of the leaflets. Such ceratozamias thrive today in extratropical areas near the present limits of distribution of the genus along the Sierra Madre Orientale in north-eastern Mexico, in particular C. microstrobila Vovides & J.D. Rees and others of the C. latifolia complex, as well as C. hildae G.P. Landry & M.C. Wilson ('bamboo cycad'). The occurrence of Ceratozamia suggests subtropical to warm-temperate, almost frostless climate and a high amount of precipitation. The accompanied fossil vegetation of both species corresponds well with the temperature regime. While the Oligocene species in Hungary probably thrived under sub-humid conditions, the remaining occurrences of fossil Ceratozamia were connected with humid evergreen to mixed-mesophytic forests. [ABSTRACT FROM AUTHOR]

Abstract: Pollen grains extracted from the cycad pollen cone Androstrobus prisma Thomas et Harris 1960 from the Bajocian of Yorkshire were studied by means of LM, SEM and TEM. The species is characterized by rounded-oval, inaperturate pollen with an indistinctly verrucate surface and predominantly homogeneous exine with occasional alveolate areas. Present and earlier published data on the fine morphology of pollen grains of fossil cycads are discussed in the light of the differentiation between Mesozoic non-saccate and presumably monosulcate pollen produced by a number of gymnosperm groups. Although the exine pattern in pollen grains of fossil cycads is usually indistinct in transmitted light, SEM reveals minute, but various sculpturing that can be used for taxonomic purposes, particularly to differentiate between species. Elongated ectexinal alveolae, situated mostly in one row and covered by a thin tectum, is an unequivocal cycadalean character. Sufficiently well preserved fossil cycad pollen clearly shows this type of exine ultrastructure. Poorly preserved cycad pollen grains commonly show an alternation of alveolate and homogeneous regions in the exine with predominance of homogeneous regions. This peculiar mode of preservation can be used as a hint to reveal cycadalean affinity. Inaperturate pollen grains are unknown in bennettites or ginkgophytes. Therefore, if a dispersed, non-saccate and boat-shaped pollen grain is proved by means of electron microscopy to lack an aperture, this would indicate a possible cycadalean affinity. [Copyright &y& Elsevier]

Abstract: A new species of Weltrichia (Williamsoniaceae: Bennettitales) is described from the Middle Jurassic of Oaxaca. The specimens come from the Tecomazuchil Formation in the Ayuquila region, at the border between the Oaxaca and Puebla states. Fossils are preserved as impressions and compressions, in a fine-grained sublitharenite sequence deposited in a fluvial environment. Preserved diagnostic characters include: large size; a cup-shaped receptacle showing seven radially arranged and basically fused microsporophylls bearing synangia. Microsporophylls are ornamented with longitudinal striations and fine brittled hairs on the edge of their wide base, and taper into a narrow distal tip. In the adaxial part of the microsporophylls seven to nine synangia are observed. These characters differentiate the new species Weltrichia mixtequensis from all previously recorded species from Mexico or elsewhere. The presence of this new species in the Middle Jurassic strata of the Ayuquila region add to the scarce fossil record of microsporangiate structures in the Jurassic flora of Mexico. [Copyright &y& Elsevier]

Fossil cycadalean leaves recorded from the Miocene plant assemblage of Soma, western Turkey, are described and assigned to an extinct genus and species, Pseudodioon akyoli. Leaf macromorphology suggests affinity with members of the Zamiaceae (subfam. Encephalartoideae), particularly with modern Dioon. Micromorphological features on the other hand indicate affinity with modern Cycas (Cycadaceae). Ordinary cells on the adaxial epidermis are isodiametric and are not differentiated into thick- and thin-walled cells. This is similar to Encephalartoideae-like fossils reported from the Cenozoic of the Northern Hemisphere, and even from the Mesozoic. Shared macromorphological traits of P. akyoli and other coeval Encephalartoideae-like fossil cycadalean leaves from Europe suggest that an extinct group of cycads inhabited southern Europe from the western part of Turkey, through Greece and France to Switzerland in the north during the Oligo-Miocene. [ABSTRACT FROM AUTHOR]

Influential arguments have been advanced in Australian archaeology concerning the origins and development of social and economic change in the mid-late Holocene (Lourandos 1997). One example used to support this claim is the perceived existence or ceremonial feasting events held in the semi-arid and rugged sandstone gorge systems of central Queensland, attended by large groups of people for extended periods, and underwritten by large quantities of kernels from the cycad Macrozamia moorei (Beaton 1977, 1982: see also Lourandos 1997). However the reexamination of the macrobotanical evidence from archaeological sites in this region using taphonomic analysis, replicative processing experiments, recalculations of seed density and estimations of the minimum numbers of seeds, does not support this model. This re-examination questions the role of Macrozamia seeds in the context of socio-economic change and suggests new interpretations of Macrozamia resource use. [ABSTRACT FROM AUTHOR]

The article focuses on the petrified wood specimens taken from Karnes and Live Oak counties in Texas. Both counties are known for petrified-wood that manifest through late Eocene to Oligocene sediments and found to have undergone extensive primary and secondary mineralization that produce colored and patterned specimens. Moreover, the article discusses the difference between fossil cycads and polygonally fractured wood fossil.

Abstract: The Carnian flora from Lunz (Lower Austria) ranks among the richest and most diverse fossil floras from the Upper Triassic. It is one of the first modern Triassic floras with bennettitaleans. Although this flora is often referred to in the literature, modern taxonomic studies are mostly absent; only some of the reproductive structures have been studied in detail. Many of the plant remains yield excellently preserved cuticles. During a systematic study of the Pterophyllum leaves from Lunz, it appeared that several species previously accommodated in that taxon have to be transferred to other genera. This paper deals with four species that are transferred to Nilssonia (cycadalean foliage); the macromorphology and epidermal anatomy are described and discussed. The following new combination is introduced: Nilssonia riegeri nov. comb. Two new species are described (i.e. Nilssonia lunzensis and Nilssonia neuberi) based on material originally mentioned in a species list as Ctenis lunzensis Stur nom. nud. and Pterophyllum neuberi Stur nom. nud. The diagnosis for a fourth species, Nilssonia sturii Krasser, is emended. The Nilssonia species from Lunz range among the earliest representatives of the genus Nilssonia. [Copyright &y& Elsevier]

This article features cycads found in Southeastern Utah. Most Mesozoic cycad trunks belong to an extinct order called Cycadeoidales. These plants looked similar to modern cycads but contained cones in their trunks instead of on top of the plant. Although true or modern cycads existed during the Mesozoic, they produced fewer fossil trunks than the extinct variety. Cycads are uncommon, and considerable time must be allowed for their exploration; however, weathering is constantly exposing these texturally complex and colorful specimens.

Focuses on the Eostangeria Barthel (Extinct cycadales) from the paleogene of Western North America and Europe. Systematic paleontology; Distinction from pteridophytes; Geographic and stratigraphic distribution.

Focuses on the study which described the Cycadalean taxa of Argentina. Details on the Argentinian fossil cycad record; Character analysis; Discussion and conclusions.

Presents an abstract of the study `Fossil and extant cycads: A cladistic analysis,' by Dennis WM. Stevenson and Analia E. Artabe and presented during the 1995 Annual Meeting of the Botanical Society of America.