A critical review of S. V. Meyen’s “Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record”

Meyen’s “Basic features of gymnosperm systematics and phylogeny as evidenced by the fossil record” departs from the usual Botanical Review article that provides the botanical community with a synthesis of the state of knowledge and understanding of an individual segment of botany, i.e., an interpretation of progress in a specialty for the nonspecialist. Instead, this article appears intended to challenge paleobotanists to reconsider traditional views of the interrelationships of the various gymnospermous groups and the concepts on which they were based. A classification scheme is presented which divides gymnosperms into the Ginkgoopsida, Cycadopsida and Pinopsida. These classes are based on Meyen’s analysis of the structural variation in gymnosperms and his interpretation of homologies of various organs. Too often, however, key plants are reconstructed from parts known only in association and relationships are tied to assumptions of homology that have yet to be documented. The result has value in providing a succinct summary of gymnospermous structure and variation in the different groups. It is also commendable in its attempt to explain and use concepts and terminology designed especially for gymnosperms. This critique shows that in many cases there are alternative interpretations that also fit the evidence.     

Devonian floral assemblages and plant megafossils from the Iberian Peninsula: A review

This paper presents a review and critical analysis of the literature on Devonian floras of the Iberian Peninsula. Although the known outcrops of Devonian strata in the Iberian Peninsula are marine, in some cases, a few fragmentary remains of vascular plants are associated with faunal remains. Records include largely specimens from the Lower Devonian of Barrancos (Alentejo, Portugal) and the Upper Devonian of Sierra de Hornachos in Badajoz province, southwest Spain; the remainder consists of drifted plant fragments from scattered sites in the Iberian Peninsula ranging in age from Lochkovian to Upper Devonian-Earliest Carboniferous. The vegetation inferred for the Lower Devonian of the Iberian Peninsula is mainly based on palynological data and corresponds to herbaceous types characterised by bryophytes, rhyniophytes (Horneophyton, Cooksonia, Rhynia), trimerophytes (Psilophyton, Pertica and Hostinella), primitive lycophytes (Drepanophycus) and incertae sedis such as Nothia and Chaleuria, all flora that developed near the coast in low-lying and, at least periodically, wet areas. In the Middle Devonian, two vegetation strata can be recognised: herbaceous (Psilophyton) and semi-arboreal (Cladoxylales). Although three levels of vegetation in the Upper Devonian, have been described from outcrops worldwide, the scarce available data from the Iberian Peninsula only indicate an arborescent lycopsid vegetation and species with uncertain botanical affinity such as Sphenopteridium keilhauii Nathorst.     

Composition and dynamics of the great Phanerozoic Evolutionary Floras

Factor analysis of a data set representing the global distribution of vascular plant families through time shows the broad pattern of vegetation history can be explained in terms of five Evolutionary Floras. The Rhyniophytic (=Eotrachyophytic) Flora represents the very earliest (Silurian and earliest Devonian) vascular plants, notably the Rhyniophytopsida. The Eophytic Flora represents the early (Early–Middle Devonian) mainly homosporous land plants, notably the Zosterophyllopsida, Trimerophytopsida and early Lycopsida. The Palaeophytic Flora represents the Late Devonian and Carboniferous vegetation, which saw the introduction of heterospory among the spore producing plants and of early gymnosperms. The Mesophytic Flora first appeared in the Late Carboniferous and Permian macrofossil record, although there is palynological evidence of these plants having grown earlier in extra‐basinal habitats and was dominated by gymnosperms with more modern affinities. The Cenophytic Flora that first appeared during Cretaceous times was overwhelmingly dominated by angiosperms. The end‐Devonian, end‐Triassic and end‐Cretaceous mass‐extinction events recognized in the marine fossil record had little impact on the diversity dynamics of these Evolutionary Floras. Rather, the changes between floras mainly reflect key evolutionary innovations such as heterospory, ovules and angiospermy.     

Discovery of the oldest known Pterygota in the Lower Carboniferous of the Upper Silesian Basin in the Czech Republic (Insecta: Archaeorthoptera)

The earliest pterygote (winged insect), dated from the Lower Carboniferous (Namurian A/E1, circa 324 millions years ago) is described from the Upper Silesian Basin in the Czech Republic. On the basis of its wing venation, it is attributed to the Archaeorthoptera Béthoux and Nel, 2002, crown group of the “Orthoptera”. Besides Apterygota (Collembola and Archaeognatha) known from the Lower Devonian, extremely rare pterygote insects are known from Lower Carboniferous deposits when they first appeared. The present discovery supports the hypothesis of the presence of the ancestor lineage of the orthopteroid in the Lower Carboniferous ecosystems.     

Fossil flora from the Aleksandrovskoe locality (Lower Permian,Kungurian; Krasnoufimsk district of the Sverdlovsk Region): Taxonomical composition,taphonomy, and a new lycopsid representative

The Aleksandrovskoe locality (Krasnoufimsk district of the Sverdlovsk Region, Fore-Urals; Lower Permian, Kungurian Stage, Koshelevsk Formation), its taphonomy and taxonomic composition of the fossil flora are discussed. A new lycopsid, Ufadendron ufaensis gen. et sp. nov., with well-developed infrafoliar aerenchyma is described. The new plant is morphologically similar to the group of Early Carboniferous Central Angaran lycopsids (Tomiodendron Radczenko emend. S. Meyen, Lophiodendron Zalessky emend. S. Meyen, Angarophloios S. Meyen). Survival of a relic lycopsid of Central Angaran type with infrafoliar aerenchyma at the periphery of Angaraland up to the mid-Permian is discussed in terms of the “Lazarus taxa” phenomenon.     

中国四川龙门山地区泥盆系牙形石

龙门山地区泥盆系地层发育,厚度大,一般为２０００－４００００ｍ,最厚达５０００ｍ以上,化石丰富,门类众多。主要有腕足类、珊瑚、双壳类、三叶虫、头足类、竹节石和层孔虫等。碳酸盐岩地层中发现了大量的牙形石。作者对桂溪、雁门坝和硫铁矿三条剖面中的牙形石做了系统工作,在雁门坝和硫铁矿剖面中,发现了丰富的Ｐａｌｍａｔｏｌｅｐｉｓ（蹼刺）。经分析研究,将该区泥盆系划分出１３个牙形石带和组合。在此基础上,对泥盆系的地层单元及下、中、上泥盆统之间的界线进行了划分,对该区泥盆纪的古生物地理进行了分析。     

Family coelotubuliporidae fam. nov. and morphological parallelisms in the evolution of bryozoans

Morphologically complex bryozoans from the Upper Devonian and Lower Carboniferous of Eurasia that some research workers include in the order Rhabdomesida and others place in the order Trepostomata are studied. The axial zooecium is demonstrated to be of zooidal nature. A new family, Coelotubuliporidae fam. nov., is established and its position in the order Trepostomata is substantiated. It includes two genera (one new), 11 species (1 new), and four subspecies. Diagnoses of a new family, Coelotubuliporidae, the genus Coelotubulipora Yang, Hu et Xia, 1988, and a new genus, Dunaevella Gorjunova gen. nov., are presented. The following species are described: Coelotubulipora irinae Gorjunova, sp. nov., Dunaevella shishovae (Schulga-Nesterenko, 1955), and D. peristomata (Schulga-Nesterenko, 1955). The emergence of axial zooecia in representatives of the order Trepostomata is considered as one of the evolutionary ways of bryozoans due to morphological parallelisms. It is shown that data presented on the stratigraphic range and paleogeography of the family Coelotubuliporidae are of great significance for solving the problems of biostratigraphy and correlation of deposits of the Upper Devonian and Lower Carboniferous of Eurasia.     

THE NEW GENUS COPELANDELLA FROM THE CARBONIFEROUS — THE YOUNGEST KNOWN BEYRICHIACEAN OSTRACODES

A palaeocope ostracode with prominent cruminal dimorphism occurs in Lower Carboniferous strata of Nova Scotia and Ireland. It is believed to be the youngest representative of the Beyrichiidae Matthew 1886, a family hitherto only known from the Silurian and Devonian. Because of differences in lobation and adventral structures this ostracode is here assigned to the new genus Copelandelia. The occurrence of the type species Copelandelia novascotica in strata of comparable age (Viséan) in Nova Scotia and Ireland appears to add some support to the hypothesis that North America and Europe formed one supercontinent in the Paleozoic, since this species is assumed to have lived in a near-shore, or even a brackish or non-marine environment.     

Stenolaemate bryozoans from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran)

Two bryozoan species are described from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran). Trepostome Schulgina mutabilis Troizkaya, 1975 is known from the Upper Devonian (Famennian) of Central Kazakhstan. The new species Ascopora geirudensis n. sp. is the earliest known representative of the rhabdomesine genus Ascopora Trautschold, 1876.     

Discussion of the Early Devonian rhynchonellid brachiopod genus Borealirhynchia Su, 1976

The Early Devonian brachiopod genus Borealirhynchia was established by Su, 1976. Phylum Brachiopoda (Cambrian to Devonian). In: Paleontological Atlas of North China, Inner Mongolia Volume 1. Geological Publishing House Beijing, pp. 155-227 (in Chinese). It has not been previously described in detail, nor have transverse serial sections of the internal features of Borealirhynchia delerensis, the type species, been published. In this paper Borealirhynchia, along with a few species previously assigned to it, is analysed and discussed. Detailed transverse serial sections of the internal features of B.? lata Su, 1976, are provided, based on well-preserved specimens collected from the Lower Devonian strata of Dong Ujimqin Qi, northeastern Inner Mongolia. Borealirhynchia? gigantea Su, 1976 and Latonotoechia multicosta Su, 1976 are considered to be synonyms of B.? lata Su with the same external and internal characters present in all three species. Some Lower Devonian strata, in which Borealirhynchia was found and reported, from Dong Ujimqin Qi, northeastern Inner Mongolia, are fully described.     

Traces of microboring organisms in Palaeozoic conodont elements

Conodont elements from Palaeozoic strata (Ordovician, Devonian and Carboniferous) contain abundant evidence for presumed post-mortem colonisation by endolithic organisms. It is possible to distinguish several morphotypes of microcavities in conodont apatite, which show some morphological similarities to microborings in calcareous substrates. Some of them are believed to be produced by microendoliths, some others are yet unknown from calcareous substrates. The present report deals with the various kinds of microendolithic traces in conodont apatite. The significance of microborings in conodont elements is discussed.     

Sedimentary environment of Devonian pelagic limestones in the Southern Alps

Primary sedimentary structures combined with the geometry of Devonian and Lower Palaeozoic lithosomes in the Southern Alps (Austria and Italy) suggest many doubts about the published environmental and bathymetric interpretation of some Lower to Middle Devonian pelagic nodular limestones as 'deep-water' abyssal deposits. Every graded bed is not necessarily aturbidite; a single or some turbiditic beds are not necessarily deep-water or abyssal deposits; carbonate dissolution does not necessarily take place only below the carbonate compensation depth (CCD). Data show that graded allodapic beds, like those of the Lower to Middle Devonian of the Alps, may have been deposited as storm layers at a depth not exceeding some hundreds of metres. Accordingly the margins between Lower Devonian shallow-water platform and basins were characterized by low gradient and transitional sedimentary conditions. They became very steep only at the Devonian–Carboniferous transition because of synsedimentary block faulting.     

Lower Devonian biostratigraphic correlation in Eastern Australia and Western North America

Savage, N. M.: Lower Devonian biostratigraphic correlation in Eastern Australia and Western North America.
Correlation of Lower Devonian marine strata of Eastern Australia and Western North America can be attempted using several fossil groups. In general the faunas are similar, with many species common to both areas. Graptolites occur infrequently, but are of great value because of their precise zonal significance. Several of these graptolites occur in the classic type sequences of Bohemia but are absent from the Rhineland stages. For this reason, and because of the Bohemian affinities of the shelly faunas, the Bohemian stage names are preferable to the Rhenish names for use in Eastern Australia and Western North America. Cono-donts are less precise index fossils than graptolites, but are considerably more abundant and therefore have greater application. Brachiopods are valuable if viewed as assemblages. In terms of the Rhenish stages, most Eastern Australian and Western North American early Lower Devonian formations appear to have been placed too high. Recent evidence from northern Canada throws new light on the problem of correlating Rhenish and Bohemian classic early Lower Devonian stages.     

Traquairaspididae and Cyathaspididae (Heterostraci) from the Lower Devonian of Poland

Lower Devonian strata from the drill cores from Poland have yielded new Heterostraci material. One ventral shield of Toombsaspis (Traquairaspididae, Phialaspidinae) discovered in the Białopole IG-1 drill core, and a fragment of dorsal shield of cf. Paraliliaspis (Cyathaspididae, Anglaspidinae) with the impressions of internal structures from Ciepielów IG-1 are described and provide new information on paleogeographic disparity of these groups.     

Post-Variscan late Palaeozoic Northern Hemisphere gymnosperms: the onset to the Mesozoic

During the Carboniferous gymnosperms became highly diverse. However, several groups became diminished toward the end of the Carboniferous and Permian, and were extinct by the end of the Permian. Relatively few groups managed to survive the Permian—Triassic transition. These remaining forms represent the gymnosperms that developed during the Mesozoic. This paper, that focuses on Euramerican floras, addresses specific problems related to the study of the gymnosperms of the uppermost Carboniferous and Permian and deals with the major floral changes in the latest Carboniferous and Permian. The major late Palaeozoic Northern Hemisphere gymnosperms are briefly discussed and special attention is given to the peltasperms and conifers, two groups that extended from the late Palaeozoic into the Mesozoic.     

The Fish Swimming Trace Undichna from the Mississippian Mauch Chunk Formation,Eastern Pennsylvania

Undichna, the swimming trace of fish, was recovered from the middle member of the Mauch Chunk Formation in eastern Pennsylvania in strata of Late Mississippian (Visean) age. These traces represent the only evidence of fish known from the Mauch Chunk Formation and the Carboniferous of Eastern Pennsylvania. The Mauch Chunk Formation in the study area is characterized by an ephemeral fluvial depositional environment that yields a diverse invertebrate ichnoassemblage of the Scoyenia ichnofacies and a tetrapod footprint assemblage dominated by the tracks of temnospondyl amphibians. The Undichna specimens are preserved on fine-grained, mudstone-draped, rippled sandstone. Two specimens, assigned to U. Britannica, consist of pairs of well-defined, narrowly incised, sinusoidal wave traces that are out-of-phase. Two specimens, assigned to U. quina, consist of two pairs of in-phase sinusoidal waves intersected by an additional single wave with a greater amplitude. Two specimens, each composed of a single wave, are assigned to U. unisulca.

The slabs of rock with the Undichna traces also preserve tetrapod undertracks assigned to Batrachichnus, Matthewichnus, and Hylopus. This trace fossil association indicates the presence of small fish, some with caudal and/or anal fins and some with pectoral, pelvic, and anal and/or caudal fins, that touched the sediment during periods of intermittent flooding of subaerial surfaces walked upon by early tetrapods. Examples of Undichna from Mississippian or older deposits, especially from a fluvial paleoenvironment, are rare; few have been reported from the Devonian and the Lower Carboniferous.     

Gymnosperm Phylogeny — A commentary on the views of S. V. Meyen

In his important contribution to the literature on gymnosperm phylogeny, “Basic Features of Gymnosperm Systematics and Phylogeny as Evidenced by the Fossil Record,” Meyen (1984) uses the classical comparative method of the morphologist and the “congregational” method, i.e., grouping by common characters, of the taxonomist. The latter may have led him to categorize some taxa on the basis of superficially similar, non-homologous characters because he used no apparently objective method to distinguish homoplasy. For this and other reasons, Meyen’s hypothesis of evolutionary relationship among gymnosperms cannot, at present, be accepted as any nearer the truth than several competing proposals. The major innovation of Meyen’s proposed phylogeny is the recognition of the clade, Ginkgoopsida, coordinate with Cycadopsida and Pinopsida. Ginkgoopsida encompasses Calamopityaceae, Callistophytales, Glossopteridales, Peltaspermales, Caytoniales, and Ginkgoales, among others. These taxa are considered to be related because, in Meyen’s view, they share the common character of primary platyspermy — i.e., the presumed platyspermic seed-type of the basal group, Calamopityaceae, is considered to have evolved directly from the pteridophytic condition of an ancestral form. This basis for Ginkgoopsida is weakened by the facts that no seeds have been discovered in organic connection with any calamopityacean and, except for the poorly-preserved seed-like structure,Spermolithus, all seeds that occur earlier in the geologic record than fossils of the Calamopityaceae are radiospermic. It is possible, therefore, that even if the platyspermic seed,Lyrasperma, found in association with the calamopityacean,Stenomyelon, were borne by that plant, it is secondarily platyspermic, having evolved from a radiospermic ancestor. The foundation upon which Ginkgoopsida was erected seems, therefore, to be rather tenuous. Other characters used by Meyen, both reproductive and vegetative are discussed. Some which he considers significant, are interpreted to be unimportant in denoting phylogeny, while others are interpreted to support alternative hypotheses. Meyen proposes that the Ginkgoopsida evolved from archaeopterid progymnosperms. This viewpoint seems to be based largely on his erroneous belief thatArchaeopteris was probably a seed plant that bore compound leaves. There is no definitive evidence that supports the view thatArchaeopteris bore seeds. On the other hand, there is strong evidence to support the contention thatArchaeopteris produced simple leaves (Carluccio et al., 1966; Beck, 1971), not compound leaves. Meyen’s phylogenetic proposal is based on data that can be and, in part, have been differently interpreted by others. Consequently, it deserves the careful and critical evaluation of all students of gymnosperm phylogeny.     

REMARKS ON THE STRATIGRAPHY AND MORPHOLOGY OF PRAGUIAN AND PROBABLY YOUNGER MONOGRAPTIDS

Praguian and probably younger graptoloids as well as the early Lower Devonian (Lochkovian) graptoloids are known from all continents except Antarctica and South America. At least five to six graptolite zones can now be distinguished in the Lower Devonian. In comparison with the Lochkovian faunas, the medial to late Lower Devonian graptoloid communities are considerably impoverished and composed exclusively of Monograptus species of the M. uncinatus group. Lino-graptus and Abiesgraptus , which are characteristic of much of the Lochkovian, are lacking in Praguian (and younger) strata. Monograptus pacificus from the southeast Alaskan Karheen Formation appears to be the youngest true graptolite known to date, possibly having a stratigraphic position not far away from the Lower/Middle Devonian boundary.     

A critical account of recent records of Devonian megaflora from the Iberian Peninsula,in geological context

Records of plant megafossils in the Devonian of the Iberian Peninsula refer to sparse drifted remains in marine strata, apart from unidentifiable debris, and misidentified ichnofossils. The age attributions are sometimes questionable. A critical analysis leaves only five localities with incidental Devonian plant megafossils capable of sustaining approximate taxonomic identifications. Another two localities of possible late Devonian age are more likely earliest Carboniferous. The various records are discussed in their geological context, taking into account that the Iberian Massif was constituted from different terranes in Pennsylvanian times. A critical discussion is presented of the reviews published by Montero (2008) and Montero and Diéguez (2010), particularly the latter which adds considerations on floral composition and sedimentary environments which lack a factual basis. A later paper by Cascales-Miñana et al. (2011) is commented on.