An anatomically preserved lycopsid from the Upper Devonian of South China

An anatomically preserved lycopsid, Lobodendron fanwanensegen. et sp. nov. Liu, Wang, Xue & Meng, is described from the Upper Devonian (Famennian) Wutong Formation of Changxing County, Zhejiang Province, China. The fossil plant bears slender, dichotomously branched axes. The vascular strand consists of solid terete primary xylem and lobed secondary xylem, which implies the result from the activity of possibly discontinuous cambium. The new plant has character combinations that do not conform to any branches in the canopy of the tree-lycopsids known previously, but resemble those of the basal part of some pseudoherbaceous lycopsids. This new plant may exemplify a Late Devonian lycopsid with a pseudoherbaceous growth habit.     

Sublepidodendron grabaui comb. nov., a lycopsid from the Upper Devonian of China

Sublepidodendron wusihense (Sze) Sze and Lepidostrobus grabaui Sze were based on compressions from the upper part of the Wutung Formation (Famennian) of Jiangsu, South China. After studying the morphology and anatomy of abundant well-preserved specimens from two localities, Sublepidodendron wusihense and Lepidostrobus grabaui are reconsidered and viewed as Sublepidodendron grabaui (Sze) comb. nov. This plant is an arborescent, heterosporous lycopsid known from trunk, branches and cones. Leaf bases are spirally arranged, fusiform in outline, with a vascular bundle scar and keel. One specimen is known with a cone attached at the tip of a distal branch. The trunk has an intrastelar parenchyma concentration (pith), exarch primary xylem and secondary xylem. The branch anatomy varies from exarch primary xylem with a small, centrally located pith, to a solid exarch primary xylem strand. Based on the morphology and anatomy of both vegetative and reproductive organs, Sublepidodendron grabaui is placed into Sublepidodendraceae ( sensu Kräusel & Weyland, 1949), and Isoëtales ( sensu DiMichele & Bateman, 1996).  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 299–311.     

A new homosporous,arborescent lycopsid from the Middle Devonian of Xinjiang,Northwest China

Abstract: A new arborescent lycopsid, Hoxtolgaya robusta gen. et sp. nov., is described from the Middle Devonian of Xinjiang, Northwest China. It has stems up to 90 mm wide with fusiform leaf bases and long linear microphylls. Sporophylls are not aggregated into strobili and are isomorphic, with sporangia homosporous and bearing Acinosporites‐type microspores. A syndrome of characters in Hoxtolgaya, including the arborescence and the homospory, implies that the arborescent habit is not necessarily correlated with the heterospory in the early evolution of arborescent lycopsids. Homosporous, arborescent lycopsids probably represent one of the transient forms between the Devonian herbaceous protolepidodendrids and the Devonian–Carboniferous heterosporous arborescent lycopsids.     

New perspective on the architecture of the Late Devonian arborescent lycopsid Leptophloeum rhombicum (Leptophloeaceae)

A reinvestigation of the previously described Leptophloeum rhombicum trunk from the Late Devonian (Frasnian) Huangchiateng Formation of Hubei, China provides a new perspective on the architecture of this arborescent lycopsid. It is preserved as a flattened, silicified petrification with an unevenly permineralized primary vasculature and spirally arranged rhombic leaf cushions, which agree with the diagnosis of L. rhombicum Dawson distributed worldwide in the Late Devonian. Taxonomically, this plant should be assigned to its own family and within the order Iso?tales sensu lato. The anatomy, from different levels of the trunk, demonstrates that the ontogeny of the plant may conform to a determinate growth pattern. Combining previous data with current architectural analysis, it suggested that the L. rhombicum tree had a pseudomonopodial branching pattern rather than an iso-dichotomous branching crown as previously proposed. New reconstruction of the general habit for this tree is given and consists of three major architectural units: a stigmarian rhizomorph, a main trunk, and lateral branches. When these results are considered with recent cladistic work, L. rhombicum may have developed similar growth architecture to some Famennian and Carboniferous arborescent lycopsids. This growth represents one of the archetypal architectures found in the Iso?tales s.l. extending from the early Late Devonian.     

New materials of Sphinxiocarpon,a seed-like organ of putative lycopsid affinity,from the Late Devonian of Hubei,China

New materials of a seed-like organ, Sphinxiocarpon wuhanium (Li, Hilton et Hemsley) Wang, Xue et Prestianni, from the lower part of the Wutung Formation (Frasnian) at Xiannüshan Quarry of Wuhan, eastern Hubei, China provide new insights into its dehiscence mechanism. It is suggested that the oblique, longitudinally striated fibers within the sporophyll tissue serve as a structural mechanic to dehisce, and that the fimbriately opened apex of S. wuhanium is likely a result of the tissular dissolution and mechanical dynamics within its sporophyll and sporangial wall when it becomes mature. Sphinxiocarpon Wang, Xue et Prestianni, neither a seed nor a preovule, has the closest affinity to lycopsids and might represent an aberrant developmental form and/or an ecological adaptation to the local adversity.     

A novel lycopsid from the Upper Devonian of Jiangsu, China

A new lycopsid, Monilistrobus yixingensis gen. et sp. nov., is described from the Wutung Formation (Famennian, Upper Devonian) of Jiangsu, China. The plant has many features typical of other Upper Devonian lycopsids, including dichotomous branching, helically arranged obovate expanded leaf bases, linear leaves with spiny appendages along the lateral margins, sporophylls widened proximally, and one elliptical sporangium attached to the adaxial surface. The most distinctive novel feature of the plant is that the modified sporophylls are arranged tightly into fertile zones or cone-like structures that are separated by lengths of axes with more lax sterile microphylls only: therefore the cone-like structures are strung along the branches like beads on a necklace.     

A new lycopsid megaspore cone from the Upper Devonian of Chaohu, China

A new small lycopsid cone, Minostrobus chaohuensis gen. et sp. nov. , is described from the upper part of Wutung Formation (Famennian) of Chaohu, Anhui, China. Six sporophylls in each whorl are tightly arranged on the cone axis. Each sporophyll consists of a short pedicel and a narrow lamina with smooth margins. One spherical to spherical-ellipsoidal sporangium is attached directly to the adaxial surface of each sporophyll. Each sporangium contains four megaspores. A solid exarch protostele occurs at the centre of the cone axis, and a mesarch protostele in the base of the sporophyll. M. chaohuensis is interpreted as a small, herbaceous, heterosporous lycopsid.     

关于木本石松植物鳞皮木属的正确名称

讨论了木本石松植物鳞皮木属Lepidophloios Stemberg的正确名称。基于Stemberg 1825年的原始描述和相关文献以及模式标本,Lepidophloios实际上是一个晚出的拼写变体,它的原始拼写为Lepidopfloyos。根据《国际植物命名法规》（维也纳法规规则60．1和61．1）,Lepidofloys Stemberg应该是鳞皮木属的正确名称。作者给出了鳞皮木属模式标本的图片和描述。     

Rotafolia songziensis gen. et comb. nov., a sphenopsid from the Late Devonian of Hubei, China

A sphenopsid from the Upper Devonian (Famennian) Xiejingsi Formation, south-western Hubei Province, China, previously named as various species in Sphenophyllum , Hamatophyton , Bowmanites and Sphenophyllostachys , is now reinvestigated and assigned to a new taxon, Rotafolia songziensis gen. et comb. nov. Its ribbed axes are anisotomous and possess slightly expanded nodes. Lateral axes are inserted at nodes on main axes. Whorls of much divided vegetative leaves are attached at nearly right angles to nodes of basal axes, and at acute angles to nodes of terminal axes. There are six leaves per whorl. The terminal strobilus includes a central axis and verticils of fertile units. Each fertile unit consists of a bract and numerous sporangia. The margin of the elongate-cuneate bract bears a distal and many lateral elongate segments. Clusters of elongate sporangia are abaxially attached to the base of the bract at the same level. The axis has an actinostele, composed of a three-ribbed, exarch primary xylem and radial secondary xylem. Although Rotafolia songziensis closely resembles Hamatophyton verticillatum in axis character, leaf morphology and primary xylem type, they are quite different in strobilar structure. Taxonomically, Rotafolia is placed in the order Sphenophyllales by three well-defined characters: 1) whorled appendages; 2) ribbed protosteles; 3) exarch primary xylem maturation.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 21–37.     

A Late Devonian isoetalean lycopsid, Otzinachsonia Beerboweri, gen. et sp. nov., from north-central Pennsylvania, USA

Compressions and impressions of an isoetalean lycopsid, comprising lower portions of stems, lobed bases, attached rootlets, and rounded rootlet scars, discovered in Late Devonian (Famennian) rocks of Clinton County, north-central Pennsylvania, Appalachian Basin, USA, are here described as Otzinachsonia beerboweri, gen. et sp. nov. These specimens demonstrate unequivocally the existence of the isoetalean lobe-and-furrow rhizomorphic growth pattern as early as the Late Devonian. They were found in an Archaeopteris- and Rhacophyton-dominated flora at Red Hill, an outcrop of the Duncannon Member of the Catskill Formation. The fossils were found in a dark-gray to greenish-gray lenticular siltstone layer that has an average thickness of 1.0 m. This deposit is interpreted as a floodplain pond. The low-energy nature of the deposit and the fine preservation of the intact rootlets of the specimens imply little or no transport. The plants were probably growing along the edge of the floodplain pond with their lower portions submerged for at least part of the year.     

New Observations on Leptophloeum rhombicum from the upper Devonian of Hubei,China

A petrified stem of Leptophloeum rhombicum is described from the Huangjiadeng Formation of the Upper Devonian in Changyang, Hubei. In the xylem of the axis, the secondary xylem is not preserved, the greatest part of the primary xylem is composed of metaxylem tracheids that are scalariform and have Williamson's striations. Based on their connections between adjacent transverse bars Witliamson's striations would be considered as a part of the secondary wall material. The small protoxylem tracheids form vertical ridges at the periphery of primary xylem cylinder. In cross section, the ridges appear as small radiating teeth of protoxylem. It provides further evidence that primary xylem in Leptophloeum rhombicum is similar to that in Carboniferous lepidodendrid lycopods. The opinion that the systematic position of Leptophloeum should be transferred from the Protolepidodendrales to the Lepidodendrales could be accepted and reaffirmed.     

Spiriferide brachiopods from the Famennian (Late Devonian) Hongguleleng Formation of western Junggar,Xinjiang, northwestern China

Junggar is one of the most important areas in the study of the Upper Devonian and Lower Carboniferous in the Junggar-Hinggan Stratigraphic Region. Nevertheless, abundant benthic fossils await modern taxonomic studies. In this paper, six genera and eight species of Famennian spiriferide brachiopods are described from the Duguer Member and its equivalents of the Hongguleleng Formation in western Junggar, adding new data to the Rugaltarostrum Subassemblage of the “Palaeospirifer”–Megalopterorhynchus Brachiopod Assemblage of this area. Five previously recognized species within this subassemblage are revised, including: Cyrtospirifer junggarensis F.M. Zhang [now Ulbospirifer? junggarensis (F.M. Zhang)]; Tenticospirifer tenticulum transversus F.M. Zhang [now Cyrtospirifer transversus (F.M. Zhang)]; Tenticospirifer koketekensis F.M. Zhang [now Cyrtospirifer koketekensis (F.M. Zhang)]; Mucrospirifer quadratus F.M. Zhang (now “Mucrospirifer” quadratus F.M. Zhang); and Mucrospirifer bouchadi (Muir-Wood) (now Tylothyris cf. novamexicana Stainbrook). Three additional species, Cyrtiorina houi n. sp., Goungjunspirifer sinicus F.M. Zhang, and Cyrtospirifer procumbens Simorin in Litvinovich et al., are described. Ulbospirifer? junggarensis and Goungjunspirifer sinicus are characterized by a prismatic layer. Cyrtiorina houi shows a moderately high and triangular ventral interarea, with delthyrium covered by pseudodeltidium with a rounded foramen. Cyrtospirifer procumbens can be distinguished from other species of this genus by its shallow, clearly limited sulcus with prominent primary plications, and high ventral interarea. Cyrtospirifer transversus has an alate to subpentagonal outline. Cyrtospirifer koketekensis has rounded and distinct flank plications. The ventral delthyrium of “Mucrospirifer” quadratus is covered by a pseudodeltidium. Tylothyris cf. novamexicana develops an angular sulcus in cross-section. Comparisons with the coeval brachiopod faunas from various regions indicate that, biogeographically, western Junggar has a close relationship with the Tarbagatai Mountain Range, northeastern Kazakhstan, central Kazakhstan, and Karaganda Basin, and a certain affinity with North America.     

Cyathea cranhamii sp. nov. (Cyatheaceae), anatomically preserved tree fern sori from the Lower Cretaceous of Vancouver Island, British Columbia

Permineralized cyatheaceous sori occur among remains of conifers, fungi, and other plants in newly discovered calcareous concretions from Early Cretaceous (Barremian) marine sediments of Vancouver Island, British Columbia, Canada. Sori are superficially attached in two rows to narrow pinnules and display a globose sphaeropteroid indusium. Annulate sporangia with multicellular stalks diverge from a basal, vascularized receptacle. The nearly vertical uniseriate annulus is not interrupted by the stalk. The sporangia bear 64 trilete spores with perispore sculpturing that ranges from irregular granulate/echinate to prominent rodlets. These specimens, described as Cyathea cranhamii sp. nov., are the first anatomically preserved tree fern sori from the fossil record. They represent the most ancient evidence for fertile structures of the Cyatheaceae and demonstrate that essentially modern species of cyatheaceous tree ferns had evolved by the Early Cretaceous.     

Gymnosperm trees from the Permian of Antarctica: An anatomically preserved trunk of Kaokoxylon sp.

Anatomically preserved gymnosperm axes are relatively abundant in Permian localities of Antarctica, but their anatomy has rarely been studied in detail, which limits comparison with other Gondwanan morphotaxa. Here we describe a silicified trunk collected from the Upper Permian Buckley Formation at Coalsack Bluff, in the central Transantarctic Mountains. The trunk has a small heterogeneous pith approximately 4 mm in diameter containing conspicuous sclerotic nests, endarch primary xylem maturation, paired leaf traces, and secondary xylem of the Araucarioxylon type. Comparison with contemporaneous gymnosperm axes from Antarctica indicates that the Coalsack Bluff trunk represents a new Permian morphotaxon for the region. The anatomical characters of the pith and secondary xylem suggest an affinity with the genus Kaokoxylon Kräusel, previously reported from Permian and Triassic localities of Southern Africa, South America, India, and Australia.     

Some Paleozoic Relics from the Late Triassic in Western Hubei,China

This paper deals with a few fossil plants of the Jiuligang Formation found ill Jingmen-Dangyang Basin, western Hubei, China. Of which a few are related to paleozoic taxa, such as Compsopteris laxivenosa sp. nov. and C. xiheensis (Feng) comb. nov., Besides those, Paradrepanozamites dadaochangensis Chen, emend, nov. and P. minor sp. nov. are described. The geological age of the Jiuligang Formation is assigned to Carnic to early Noric.     

A set of possible sensory system preserved in cuticle of Late Devonian thylacocephalan arthropods from Poland

The cuticle of concavicarids (Arthropoda: Thylacocephala) from the early Famennian (Upper Devonian) of the Holy Cross Mountains, Poland was studied with respect to its microstructural details. Investigated laminated cuticle with phosphatic/organic composition, possesses two different kinds of microstructure with assumed sensory functions. The first kind consists of circular depressions, each located in the central area of characteristic polygons forming the carapace exterior ornamentation. These depressions are interpreted as sealed during phosphatisation processes setal lumens. The second kind occurs exclusively in carapace margins. These intracuticular microstructures occur as elongated tubular structures, circular to oval in cross section, penetrating the cuticle interior but not reaching its surface. They form a thin belt with a kind of ‘sensory fields’ on the dorsum and a wider belt in the ventrocaudal part of the carapace. These belts are connected in the rostral and caudal area, forming a continuous sensory zone encompassing each valve. These structures are very similar to crustacean organule canals, and the dorsally situated ‘sensory fields’, suggest some similarity to crustacean sensory dorsal organs. This possible sensory system is the oldest of this kind found in Thylacocephala. Its morphology and presumed canal walls mineralogical composition suggests crustacean affinity of Thylacocephala.     

Re-interpretation of Wexfordia hookense from the Upper Devonian of Ireland as an arborescent lycophyte

New collections of pyritized axes of the lycophyte Wexfordia hookense have been made from the Upper Devonian (uppermost Famennian) type locality at Sandeel Bay, County Wexford, in south-eastern Ireland. The specimens reveal additional histological features that permit reinterpretation of the morphology of this taxon and reevaluation of its taxonomic affinities. Wexfordia is shown to possess both secondary xylem, with narrow, uni- to biseriate rays, and periderm. The range of variation in relative amounts of primary and secondary xylem can be correlated with position in the mature plant. This evidence indicates that Wexfordia was a small tree rather than an herbaceous form. Fine structure of tracheids and additional anatomical features strongly support affinities with Carboniferous arborescent Isoetales, rather than Devonian Protolepidodendrales, and further support the hypothesis that radiation in this lineage was well underway prior to the Carboniferous.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 275–287.     

Akrosida floribunda (Malvaceae), a new arborescent mallow from the Dominican Republic

A new species,Akrosida floribunda, is described from the Dominican Republic. This arborescent genus is now known from two species, the other beingAkrosida macrophylla, from Brazil. Both have very limited distributions.

---

Resumen  Se describe la especie nuevaAkrosida floribunda de la República Dominicana. Este género arborescente actualmente se conoce de dos especies, la otraAkrosida macrophylla de Brasil. Las dos tienen distribuciones que son bien restringidas.

     

An exceptionally preserved Late Devonian actinopterygian provides a new model for primitive cranial anatomy in ray-finned fishes

Actinopterygians (ray-finned fishes) are the most diverse living osteichthyan (bony vertebrate) group, with a rich fossil record. However, details of their earliest history during the middle Palaeozoic (Devonian) ‘Age of Fishes'' remains sketchy. This stems from an uneven understanding of anatomy in early actinopterygians, with a few well-known species dominating perceptions of primitive conditions. Here we present an exceptionally preserved ray-finned fish from the Late Devonian (Middle Frasnian, ca 373 Ma) of Pas-de-Calais, northern France. This new genus is represented by a single, three-dimensionally preserved skull. CT scanning reveals the presence of an almost complete braincase along with near-fully articulated mandibular, hyoid and gill arches. The neurocranium differs from the coeval Mimipiscis in displaying a short aortic canal with a distinct posterior notch, long grooves for the lateral dorsal aortae, large vestibular fontanelles and a broad postorbital process. Identification of similar but previously unrecognized features in other Devonian actinopterygians suggests that aspects of braincase anatomy in Mimipiscis are apomorphic, questioning its ubiquity as stand-in for generalized actinopterygian conditions. However, the gill skeleton of the new form broadly corresponds to that of Mimipiscis, and adds to an emerging picture of primitive branchial architecture in crown gnathostomes. The new genus is recovered in a polytomy with Mimiidae and a subset of Devonian and stratigraphically younger actinopterygians, with no support found for a monophyletic grouping of Moythomasia with Mimiidae.