A new zosterophyll from the Lower Devonian of Wales

A new monotypic genus is described from impression and compression fossils preserved in the Senni Beds of the Lower Old Red Sandstone of S Wales. The new species has scattered reniform lateral sporangia suggesting zosterophyll affinity, but supporting anatomical evidence is lacking. The axes of the plant are characterized by occasional large surface protuberances, sometimes extended into lateral projections of variable length and morphology. Taphonomic factors account for some of the observed features of the fossils, and their unusual orientation in the sediment suggests that Tarella may have grown on exposed point bars.     

A new genus for isolated bivalved sporangia with thickened margins from the Lower Devonian of the Welsh Borderland

A new taxon Sporathylacium salopense gen. et sp. nov . is based on small isolated coalified sporangia from the Lower Devonian (Lochkovian: micrornatus—newportensis spore zone) from the Welsh Borderland. The sporangia have two equal valves with multi-layered walls and thickened borders, and contain trilete crassitate, non-curvaturate isospores that are completely covered by a microgranular ornament with possible distal verrucate/murornate structures. They differ from zosterophyll sporangia in details of the presumed dehiscence zone extending around the entire free convex margin, particularly in the presence of a wedge of amorphous material between the valves, and in spore characters. Absence of any information relating to water-conducting cells prevents further assignment within the embryophytes. Spherical bodies associated with spores and a resilient sporangial lining are compared with similar structures in extant free-sporing plants and with Ubisch bodies. The mode of sporangial dehiscence involving anatomical modifications of the valve margins and the novel wedge of tissue which connects them remains speculative.     

Lower Devonian Polyplacophora from New South Wales, Australia

Silicified polyplacophorans are common in the Lower Devonian Garra Formation in New South Wales. Four taxa occur within the lower 237 m of the formation at 14 horizons associated with an abundant and diverse fauna. Chelodes calceoloides Etheridge ranges through the section. New taxa are Chelodes cordatus sp. nov., Acutichiton depressolatus sp. nov., and Jugochiton patulus gen. and sp. nov. A single plate of an indeterminate genus occurs in the lower portion of the Camelford Limestone.     

A trigonotarbid arachnid from the Lower Devonian of Tredomen, Wales

A new trigonotarbid (Arachnida: Trigonotarbida) Arianrhoda bennetti gen. et sp. nov. is described from the Lower Devonian (Lochkovian) of a quarry near Tredomen, Powys, mid Wales, UK. This relatively complete specimen is the first record of a pre-Carboniferous arachnid from Wales, one of only a handful of early Devonian arachnids, and the second oldest trigonotarbid recorded. Based on the rounded prosomal dorsal shield and the relatively narrow, elongate opisthosoma we refer this new fossil to the family Anthracosironidae. A distinct flange-like ornament on the leg 4 tibia in the new fossil is unique among trigonotarbids and is the primary autapomorphy for the new genus.     

A new aglaspidid arthropod from the Lower Ordovician of Wales

A new genus and species of aglaspidid arthropod, Tremaglaspis unite , is described from the well-known upper Tremadoc locality of Y Garth in North Wales, and compared with other Cambrian and Ordovician taxa. It is remarkable in having a large hypostome, a character shared with other primitive arachnomorphs.     

Some new acanthodian material from the Lower Devonian of Europe

The following material is described: (a) a climatiid shoulder girdle from the Old Red of Podolia and the British Lower Old Red Sandstone, and (b) ischnacanthid jaw-elements and a fin spine from the Lower Devonian of Vestspitsbergen. A discussion is given of the shoulder girdle in Climatius reticulatus and of the characters distinguishing the dentigerous jaw-bones of the Ischnacanthidae from those of the early Climatiidae. It is pointed out that in the dermal skeleton of the Climatiidae one may trace phylotie changes in the structure of mesodentine and bone tissue closely paralleling those of the corresponding hard tissues in the Osteostraei. A trend towards the emergence of acellular bone tissue is traceable not only in the Climatiidae but also in certain parts of the dermal skeleton of the Ischnacanthidae.     

A new microphyllous plant from the Lower Devonian of Yunnan Province, China

Sterile and fertile shoots of a microphyllous vascular plant are described from the Lower Devonian Posongchong Formation (? upper Siegenian), Yunnan Province, southern China and placed in the new taxon Halleophyton zhichangense gen. et sp. nov. The sterile axes are characterized by conspicuous, contiguous swollen rhomboidal to hexagonal leaf bases and relatively broad spatulate laminae. The relief of the leaf bases is not so pronounced in the fertile areas, which bear numerous cauline sporangia with two equal valves. In vegetative characters the new fossils, although smaller and more fragmentary, resemble Drepanophycus gaspianus but in the absence of information on the fertile parts of the latter and because of the controversy surrounding the concept of the genus Drepanophycus, we decided to erect a new genus. Its relationship to the lycophytes sensu stricto is equivocal as exact details of the relationship of sporangium with leaf and sporangium vascularization remain unknown.     

A cyanolichen from the Lower Devonian Rhynie chert

The 400 million-year-old Rhynie chert has provided a wealth of information about various types of fungal interactions that existed in this Early Devonian paleoecosystem. In this paper we report the first unequivocal evidence of a lichen symbiosis from the Rhynie chert. Specimens of a new genus, Winfrenatia, consist of a thallus of superimposed layers of aseptate hyphae and, on the upper surface, numerous uniform depressions. Extending into the base of each depression are hyphae that form a three-dimensional netlike structure. Enclosed within each of the net spaces is a coccoid cyanobacterium, each cell of which is surrounded by a thick sheath. These photobiont cells divide in three planes, resulting in cell clusters of up to perhaps 64 individuals. The photobiont is parasitized by the fungus in the base of each net as new cyanobacterial cells are formed distally. Reproduction is by endospores and soredia. Affinities of the mycobiont appear closest to members of the Zygomycetes, while the photobiont is most similar to coccoid cyanobacteria of the Gloeocapsa and Chroococcidiopsis types. We speculate that this cyanobacterial symbiosis was well adapted to exploit and colonize new ecological niches, especially in the periodically desiccated environment postulated for the Rhynie chert paleoecosystem.     

A new plant with novel leaves from the Upper Devonian of Zhejiang Province,China

The evolution of vascular plants during the Devonian Period has had great impacts on terrestrial ecosystems through innovations of key characters such as leaves, heterospory, seed reproduction, and woods. Here we report a new plant, Qianshouia mira n. gen. n. sp., from the Upper Devonian Wutong (Wutung) Formation of Fanwan section, Changxing County, Zhejiang Province, China. This plant has slender axes which seldom branch. Its leaves are arranged in pseudowhorls, departing from axes with an acute angle. The leaves are strap-shaped and each can be subdivided into proximal, middle and distal portions. At the proximal portion, a middle ridge develops, and at the middle portion this ridge divides at least three times forming four to six daughter ridges, and in between are grooves. The distal portion of leaves (leaf apex) is suggested to be adaxially curved, with no ridges but with forked tips. Qianshouia probably represents a small plant with a shrubby or herbaceous habit. Due to the unique leaf morphology and the lack of fertile structures and anatomy, the exact phylogenetic position of Qianshouia is uncertain. Qianshouia might be a lycopsid in light of the pseudowhorled phyllotaxis, or alternatively, could be a sphenopsid if the dichotomous ridge system of the leaf could be demonstrated to be leaf veins. Nevertheless, Qianshouia adds to the diversity of leaf morphologies among the Late Devonian vascular plants.     

莼菜绒毡层细胞中核糖体的解体与花粉外壁蛋白的形成研究

莼菜（Ｂｒａｓｅｎｉａ ｓｃｈｒｅｂｅｒｉ Ｇｍｅｌ）的绒毡层属腺质绒毡层。四分体时期是绒毡层细胞发育的高峰期,大量膨胀的内质网互相连接,在切面网格构布满细胞,用三维空间结构分析,内质网从多的小室,每个小室中充满核糖体。四分体发育后期,内质网小室中的核糖体开始解体,形成高电子密度的球形体,内质网消失后,从金钱求证菜体游离于细胞基质中。花粉单核期,球形体通过质膜进入花粉囊。在花粉外壁形成 ,球形体不     

Disruption of the novel plant protein NEF1 affects lipid accumulation in the plastids of the tapetum and exine formation of pollen, resulting in male sterility in Arabidopsis thaliana

A novel male-sterile mutant of Arabidopsis thaliana was isolated by means of T-DNA tagging. Pollen abortion of the mutant was evident after microspore release, and pollen grains were completely absent at anthesis. Transmission electron microscope analysis revealed that primexine was coarsely developed, and that although sporopollenin was produced, it was not deposited onto the microspore plasma membrane. The sporopollenin that failed to be deposited aggregated and accumulated within the locule and on the locule wall. Finally, as no exine formation was observed, the mutant was named nef1. The plastoglobuli within the plastids of the tapetum were reduced, and lipid accumulation was considerably decreased. The mutant had a significantly altered leaf chloroplast ultrastructure and showed various growth defects. Lipid analysis revealed that the total lipid content in nef1 was lower than that in the wild type, which indicated that Nef1 was involved in lipid metabolism. Cloning of the full-length Nef1 indicated that the gene encodes a novel plant protein of 1123 amino acids with limited sequence similarities to membrane proteins or transporter-like proteins, and the NEF1 is predicted to be a plastid integral membrane protein. Motif analysis revealed that NEF1 contains prokaryotic membrane lipoprotein lipid attachment sites that are involved in maintaining cell envelope integrity. It is predicted that the Nef1 encodes a membrane protein that maintains the envelope integrity in the plastids.     

云南曲靖下泥盆统西山村组四营鱼属(Siyingia)一新种(英文)

主要采用形态学与比较解剖学的方法,对采自云南曲靖地区下泥盆统西山村组中的1件盔甲鱼类标本进行了详细的形态学研究,建立了多鳃鱼类四营鱼属1新种:宽棘四营鱼(Siyingia perlatuspinosa sp.nov.),并据此修订了四营鱼属的特征。在此基础上,应用分支系统学对多鳃鱼类属一级的系统发育关系进行了重新分析与探讨,确定了四营鱼在多鳃鱼类中的系统发育位置。系统发育分析结果显示,四营鱼(Siyingia)与多鳃鱼(Polybranchiaspis)亲缘关系最近,二者形成了一个单系类群,与宽甲鱼(Laxaspis)+坝鱼(Damaspis)组成的单系类群互为姊妹群。宽棘四营鱼的发现不仅拓宽了四营鱼在华南的时空分布范围,而且丰富了多鳃鱼类的多样性,并为多鳃鱼类的深入研究提供了可靠的化石新证据。     

A large arthropod from the Lower Old Red Sandstone (Early Devonian) of Tredomen Quarry,south Wales

Abstract: A large arthropod from the Lower Old Red Sandstone of Tredomen Quarry, near Brecon, Powys, southeast Wales is described as Bennettarthra annwnensis gen. et sp. nov. The animal is incomplete, preserved to a length of 30 cm, and displays a trunk of at least ten, non‐diplopodous segments. The trunk may be delineated into two distinct tagmata: the anterior three somites (as preserved in the fossil) appearing ornamented and apparently bearing robust, ornamented, segmented walking legs; the posterior somites appearing relatively smooth, of which at least the anterior five somites bear simple, sclerotized rudimentary appendages. Unfortunately, diagnostic features such as detailed appendage arrangement for the anterior tagma and the head and tail region are largely missing, frustrating detailed classification. However, the delineation of the non‐diplopodous trunk into two tagmata, each displaying apparently distinct appendage morphology, together with the large size of the fossil, is a feature hitherto unknown in any arthropods from terrestrial/freshwater fossil assemblages of this age. In terms of taxonomic placement, based on the currently limited morphological evidence, a malacostracan or hexapodan affinity for Bennettarthra appears most likely. The animal is preserved in laminated sandstone with plant debris, osteostracan fish and abundant thin irregularly shaped carbonaceous sheets. The sandstone was deposited from a river flood that buried and preserved articulated fish and Bennettarthra. These animals were probably buried alive and suffocated in sediment. Trace fossils including Diplichnites trackways and Beaconites burrows occur in close stratigraphic proximity to the flood deposit, and it is possible that this arthropod was the maker of one or both of these traces.     

Morphology and wall ultrastructure of the spores of the Lower Devonian plant Oocampsa catheta Andrews et al., 1975

The enigmatic Lower Devonian plant Oocampsa catheta Andrews et al. (Can. J. Bot. 53 (1975) 1719) is considered intermediate between the trimerophytes and progymnosperms. In order to shed light on its evolutionary relationships, the morphology and ultrastructure of its sporangium and spores were analysed using light, scanning electron and transmission electron microscopy. In addition, dispersed spores (Grandispora douglastownense McGregor (Palaeontographica B 142 (1973) 1) and Grandispora ?macrotuberculata (Trudy VNIGNI 37 (1963) 18) McGregor (Palaeontographica B 142 (1973) 1), considered to possibly represent forms derived from O. catheta, were also examined. It is concluded that G. douglastownense and G. ?macrotuberculata are probably end members of the same spore complex and most likely are dispersed spores produced by O. catheta. Oocampsa catheta spores are bilayered. An inner body has an innermost part consisting of continuous, parallel-stacked, laminae and an outermost part consisting of more erratic, anastomosing, laminae. The inner body is surrounded by an homogeneous outer layer that is extended at the equator forming a pseudozona, and is folded on the proximal surface forming the trilete mark and on the distal surface forming spinose ornament. The spores are partially camerate. On the inside of the sporangium wall there is a layer probably representing the residue left following degeneration of a (probably secretory) tapetum. Spore morphology, gross structure and wall ultrastructure are compared to that of extant and fossil plant groups, and it is concluded that the spores of O. catheta are highly distinctive and do not conform closely to any plant group, although they show most in common with the spores of the progymnosperms.     

A new species of Diplacanthus from the Late Devonian (Famennian) of South Africa

An advanced diplacanthid (Climatiiformes) is described from a Famennian estuariee environment of South Africa. It is characterized by having exceptionally long thin fin spines and a deep body form. Unusual details of the fins and fm spine insertions are preserved. This is the first record of a diplacanthid from the Southern Hemisphere.     

A new scolenaspidid (Osteostraci, Vertebrata) from the Lower Devonian of Podolia, Ukraine

Anew osteostracan genus and species,Victoraspis longicornualis n. gen., n. sp., is described based on material from Rakovets’, present day Ukraine. This new taxon shares characters with the two generaStensiopelta Denison, 1951 andZychaspis Janvier, 1985. A phylogenetic analysis supports the position ofVictoraspis as the sister group to a monophyleticStensiopelta, while the interrelationships of the various species ofZychaspis are poorly resolved. A morphometric analysis is carried out in an attempt to further resolve the taxonomic affinity. This analysis groups all examinedZychaspis species closely together, and further supports the establishment ofVictoraspis as separate genus.      

Lower Middle Devonian,Eifelian, crinoids from central Guangxi,South China

The extensive Devonian marine deposits of South China have yielded few articulated crinoid cups or theca. Two Eifelian specimens, from the Gupa Member, are the first ones reported from the Yingtang Formation, Eifelian, from the Ma’anshan section, Guangxi, South China. The new taxon Guangxicrinus xiangzhouensis n. gen. n. sp. is the first report of a marsupiocrinid in China, extending the paleogeographic range of the family into the Paleotethys and the stratigraphic range of the family upward from the upper Silurian into the lower Middle Devonian, Eifelian. The occurrence of Halocrinites sp. is the third occurrence of a cupressocrinitid in China and extends the paleogeographic range from Yunnan to Guangxi.