Level-bottom brachiopod communities in the Middle Devonian of New York

Depositional environments of the Onondaga Limestone from central to southeastern New York are found to be normal, subtidal marine, due to the absence of characteristic supratidal or intertidal sedimentary features and the presence of a typical, diverse, marine level-bottom community framework. Post-mortem transport has not been extensive, as evidenced by low articulation ratios, lack of abraded valves, and complete ontogenetic gradations within species, which precludes large scale winnowing. Sedimentation rates appear to have been greatest in eastern New York where the Onondaga Limestone reaches a thickness almost three times that of the strata in central New York. Shaly beds in the central area represent periods of cessation of carbonate deposition rather than an influx of clastic material. Deposition terminated with the onset of deeper water characterized by a westerly advance of terrigenous sedimentation (the Marceilus Shale of the Hamilton Group). Nine brachiopod communities can be recognized in the Onondaga Limestone. There is a strong correlation between sediment-substrate and community type, reflecting the sedimentologic control of brachiopod community distribution. Sandy facies, cherty limestones and coral biostromes and bioherms are associated with inner-neritic deposition in Edgecliff time; argillaceous lime muds and lime sands are characteristic of mid-neritic deposition in Nedrow to Moorehouse time; and highly argillaceous lime muds are associated with outer-nerittc deposition in Seneca time.     

Homeomorphy between Devonian brachiopod communities in France and Iowa

The diverse brachiopod faunas from the Calcaire de Ferques of north France and the Lime Creek Formation of Iowa show a remarkable homeomorphy. They are both of Frasnian age and occupied similar mid-shelf muddy carbonate environments. It is possible to match species in the two faunas on external form; this similarity can also be seen in the population histograms. The two areas originated in different faunal provinces, however, and serial sections show that homeomorphic forms were not genetically related. Thus it seems possible that the similarity between the two faunas is entirely a result of adaptation to similar environments.     

Two new brachiopod genera from the Lower Pragian (Lower Devonian,Soda Creek Limestone) of west-central Alaska

New strophomenid and rhynchonellid (Brachiopoda) taxa are described from the Lower Pragian (Soda Creek Limestone) of west-central Alaska: Harperoides gen. nov. with type species H. alaskensis sp. nov. (subfamily Mesodouvillinae Harper et Boucot) and Pedderia gen. nov. with type species P. fragosa sp. nov. (family Pygmaellidae Baranov).     

Lower Devonian vertebrates, arthropods and brachiopods from northern Vietnam

Additional vertebrates and ostracods from the bituminous shale of the Khao Loc Formation at Tong Vai, Ha Giang Province, northern Vietnam, corroborate its correlation with the upper part of the Xishancun (Xiaxishancun) Formation and the lower part of the Xitun and Lianhuashan formations of South China, and its Middle to Late Lochkovian age. The variations in morphology and ornamentation of the galeaspid Polybranchiaspis liaojaoshanensis from Tong Vai are discussed and regarded as possibly size and growth-related. A new acanthothoracid placoderm with a very deep dorsal process is described from Tong Vai and the specific distinction between the antiarchs Minicrania lissa from Tong Vai and M. lirouyii from Yunnan is supported by additional characters. Petalichthyid placoderms are recorded from this locality for the first time, and the skull of a juvenile youngolepidid sarcopterygian is described. Eurypterid fragments and a phyllocarid crustacean are also recorded from the Khao Loc Formation. A new species of the chonetid brachiopod genus Tulynetes, endemic to northern Vietnam, is described from the Pragian Mia Le Formation at Cu Le, Bac Kan Province, a new locality which yields a large diversity of taxa with outstanding preservation.     

The Lower Devonian Knoydart faunas

The presence of Traquairaspis symondsi and Ptertispis (Simopteraspis) whitei in the Knoydart Formation of Arisaig and Pictou Counties, Nova Scotia, has been taken as good evidence of the upper part of the Downtonian and the lower part of the Dittonian stages, respectively. Further discoveries of P. (S.) whitei and Cephalaspis novaescotiae allow some estimate of the thickness of the lower part of the Dittonian stage (more than 60 ft). Near Ardness a fauna occurring near the top of the Knoydart Formation includes Pteraspis (Belgicaspis) crouchi which confirms a lower Dittonian age for the greater part of the formation.     

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.     

The problematic cemented Devonian brachiopod Schuchertellopsis durbutensis Maillieux, 1939

The Devonian cemented brachiopod Schuchertellopsis durbutensis has proved difficult to classify and its possible taxonomic relationships are unknown. Morphologically Schuchertellopsis resembles more closely members of the Orthotetidina than the Davidsoniidina. Examination of the shell structure, a key diagnostic feature of the Orthotetidina, shows that Schuchertellopsis has the cross laminar secondary shell typical of all orthotetidines. However, the presence of both pseudopunctate and incipient an extropunctate fabric within the ventral valve is unique amongst orthotetidine brachiopods and is thought to represent a phase of shell fabric experimentation. Schuchertellopsis probably fits most comfortably within the Schuchertellidae, and is the earliest representative of that family.     

Quantitative analysis strengthens qualitative assessment: a case study of Devonian brachiopod species

Species recognition attributed to the brachiopod family Atrypidae is evaluated based on qualitative and quantified morphological characters. I identified two brachiopod species—Pseudoatrypa lineata and Pseudoatrypa devoniana—from a rich assemblage of brachiopods recovered from the middle Devonian Genshaw Formation of the Traverse Group. Qualitative examination suggested that the former had fine-medium-sized ribbing, a narrow hinge line, widened anterior, moderately steep mid-anterior fold, domal shaped dorsal valve, and an inflated ventral valve in contrast to the coarse ribbing, widened hinge line, narrow anterior, gentle mid-anterior fold, arched-shape dorsal valve, and flat ventral valve of the latter. The shell outline appears rounded for P. lineata and elongated for P. devoniana. Quantitative assessment of the morphological characters on the dorsal, ventral, anterior, and posterior regions of the valves of the two species using geometric morphometric and statistical analyses suggests that the morphologies of the two species are considerably different (P  $ \ll $  0.01). Thus, qualitative differences between the two atrypid species were further corroborated by quantitative results. This emphasizes the fact that these two species of Pseudoatrypa were indeed different from each other. This study highlights the necessity of incorporating quantified morphological characters to successfully investigate the taxonomic distinctness of fossil invertebrates to the species level.     

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 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.     

Age and distribution of the Late Devonian brachiopod genus Dzieduszyckia Siemiradzki, 1909 in southern China

Conodont biostratigraphical work was done at four sections recently found with occurrence of the rhynchonellide brachiopod genus, Dzieduszyckia Siemiradzki, in southern Guangxi and in the border area between Dushan County of Guizhou and Nandan County of Guangxi, South China. These sections represent two different types of facies, i.e., carbonate platform and intraplatform basin. The conodont analysis reveals that this genus occurs in the Upper triangularis Zone and the Middle crepida Zone at the Dazhai Section, through the Lower to Upper crepida zones at Dalong, and is restricted within the Upper rhomboidea Zone at the two intraplatform basin sections (Changtang and Duli). This result demonstrates that the occurrence of these peculiar rhynchonellide brachiopods in South China, regardless of the depositional environments, is within the Lower Famennian instead of the previously suggested Upper Famennian. Furthermore, this brachiopod genus in South China began to inhabit on the carbonate platform almost since the beginning of the Famennian and did not extend to the intraplatform basin facies until the late Early Famennian.Available biostratigraphic data indicate that during the Early and Middle Famennian, Dzieduszyckia is widely distributed not only in South China, but also throughout the world, such as Morocco and southern Ural.Observation on the new collections from the four studied sections reveals that the peculiar rhynchonellide brachiopods have a great morphological variation within each section. Significant differences existed among the collections from different sedimentary settings and localities, probably reflecting the environmental and geographic constraint on the morphology of Dzieduszyckia. Samples from different layers in the same section have nearly identical morphological variation, suggesting the temporal inheritance in morphology of the rhynchonellide brachiopod.     

<Emphasis Type=Italic>Leonispirifer leonensis</Emphasis> gen. et sp. nov., a rare new delthyridoid spiriferid brachiopod from northern Spain (Brachiopoda,Lower Devonian)

Leonispirifer, a new delthyridoid brachiopod genus characterized by capillate micro-ornamentation with marginal microspines, very few ribs, and a brachidium consisting of spirals that have a small diameter and are oriented in the posterior direction, is identified from the Emsian La Vid Group in its type section in the Cantabrian Mountains in northern Spain. Its type species Leonispirifer leonensis is described and its phylogenetic origin from Filispirifer is discussed. For the first time, 3D reconstructions of Filispirifer and Leonispirifer are prepared that show the different spiralia orientations, lateral versus posterior, of these two genera. An attempt is made to reconstruct the life habits of Leonispirifer, paying special attention to its lophophore-based filter-feeding system. Leonispirifer was hitherto known from the Emsian La Pedrosa Formation of the La Vid Group in northern Spain, and probably from the Siegenian Assa Formation (“Rich 1”) in Morocco. According to Early Devonian paleobiogeography, both regions belonged to the northern shelf of Gondwana.     

Novel conducting tissues in Lower Devonian plants

Elongate cells presumed to comprise water-conducting tissues are described from the central regions of short lengths of two naked, stomatiferous, coalified, axial fossils from Lochkovian (Lower Devonian) fluvial rocks in the Welsh Borderland. In one, a discrete central strand is predominantly composed of uniformly thickened cells that are compared with central tissues in coeval plants, e.g. Aglaophyton , and the hydroids of extant mosses. The other has at least two types of cells with pits of plasmodesmata dimensions that perforate only the inner layer of a bilayered wall. These are compared with liverwort and Takakia hydroids and the coeval S-type tracheids that characterize the Rhyniopsida. The affinities of the two axes remain equivocal. The relevance of plasmodesmata-derived pits to the evolution of diversity in water-conducting elements in early cmbryophytes is discussed.     

Marine benthic communities in the Upper Devonian of New York

Four distinctive benthic communities occur in the mid-shelf deltaic deposits of the Upper Devonian Sonyea Group: the Bellerophon Community, dominated by herbivorous gastropods and deposit-feeding bivalves; the Prodrtctella Community, dominated by brachiopods with adaptations for life on muddy substrata; the Cypricardella Community, dominated by bivalves and brachiopods with a variety of adaptations; and the Rhipidomella Community, dominated by brachiopods adapted for life on sandy substrata. The geographic and stratigraphic occurrence of the communities suggest that their distribution was controlled by two principal sets of environmental variables: (1) onshore to offshore gradients in salinity, dissolved oxygen concentrations, and sedimentary substrata, and (2) rate of delta progradation. A change in the rate of delta build-out during mid-Sonyea time led to a dramatic change in onshore to offshore community patterns. The change suggests that great care must be used in constructing generalized community models for longer intervals of Paleozoic time.     

Epizoic bryozoans and corals as indicators of life and post-mortem orientations of the Devonian brachiopod Meristella

The in-life and post-mortem orientations of the Lower Devonian brachiopod Meristella atoka from the Haragan Formation (Lower Devonian; south-central Oklahoma) are inferred from the distribution of epizoic bryozoans and the orientations of base plates of epizoic corals. Three bryozoans, Cyphotrypa corrugata, Fistuliporella maynardi and Leioclema pulchellum, and one coral, Favosites conicus, are considered. Most zoaria that contact the commissure terminate at the commissurc, and a few zoaria terminate at growth lines. This suggests that the bryozoans were primarily life associates of Meristella atoka. Collectively, these three bryozoan species most extensively encrusted marginal sectors of the brachial valve and are very rare on the posteromedian sector (the umbo) of the pedicle valve. This distributional pattern indicates that the preferred living orientation of Meristella atoka was umbo-down (posteromedian sector of the pedicle valve resting on or buried in the substratum) with the commissure steeply inclined to the sediment water interface. Most coralla of Favosites conicus that contacted the commissure encrusted over the commissure. This indicates that Favosites conicus either preferentially encrusted Meristella atoka post-mortem or colonized living brachiopods but subsequently caused them to die. Furthermore, Favosites conicus most extensively encrusted anterior sectors of the brachial valve, especially the fold. The lateral and anterior orientations of the commissure with respect to the base plates (holothecae) of Favosites conicus indicates that the brachiopods were oriented approximately horizontal with respect to the base plates. This suggests that the preferred post-mortem orientation of Meristella atoka was resting nearly horizontally on the substratum. These data and interpretations confirm previously inferred in-life orientations of Meristella atoka and are consistent with post-mortem orientations hypothesized for elongate-oval athyrid brachiopods. □Brachiopoda, Athyridacea, Meristella atoka , palaeoecology, autecology, epizoans, bryozoans, corals, sedimentology, Lower Devonian, North America, Oklahoma.     

Geochemical parameters of sedimentation and the distribution of Silurian brachiopod communities in Lithuania

Silurian rocks from borehole cores in the Baltic Basic were analyzed for Si, Al, Ti, Fe, Ca and Mg oxide content and chemical data were related to sedimentary environment, lithology and brachiopod community distribution. Evaluation of these relationships enables precise positioning of closely related communities within Boucot's (1975) brachiopod Benthic Assemblages. Preliminary attempts are made to evaluate climatic change based on Al/Ti oxide ratios.     

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.     

Sporangia containing Scylaspora from the Lower Devonian of the Welsh Borderland

ABSTRACT. Bulk maceration of Early Devonian (Lochkovian) deposits from the Welsh Borderland has yielded eight specimens of a new type of sporangium characterized by its elongate shape and distinctive spores. The specimens have been examined using scanning electron, transmission electron and light microscopy. The elongate sporangia occur isolated and are fragmented to varying degrees. They contain trilete spores that possess a proximal surface with shallow murornate ornament and a distal surface that is laevigate. The spores belong to the dispersed spore genus Scylaspora , and this is the first report of such spores in situ . Ultrastructural studies demonstrate that the spore walls are bilayered with a lamellate inner layer overlain by an essentially homogeneous outer layer. There is little or no associated extra-exosporal material. To date this is the earliest reported example of lamellate wall ultrastructure in trilete spores. Models of spore wall development are suggested in the light of evidence provided by spore wall ultrastructure. Detailed comparisons of the characters preserved in the fossils (morphological, anatomical and ultrastructural), with those in other fossil and extant plants, currently shed little light on the phylogenetic relationships of these specimens, primarily due to the paucity of comparable data. It is proposed that the plant is probably of vascular status, but in the absence of evidence for vascular tissue, it must be classified as rhyniophytoid.     

An investigation of the snowpack signal in moisture-sensitive trees from the Southern Canadian Cordillera

Variations in mountain snowpack in the western Canadian Cordillera have widespread and important impacts on ecosystems, environmental processes and socio-economic activities (e.g. water availability downstream). Historical records of snowpack generally span only the latter half of the 20th century offering a limited perspective on the causes and uniqueness of recently observed changes across the region. This paper explores the potential utility of a network of low elevation Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) tree ring-width chronologies to reconstruct past snowpack variations. Correlation coefficients between the tree-ring chronologies and a set of snow water equivalent (SWE) records are calculated and mapped. Separate analyses were carried out for total ring- width (TRW) and partial-ring measurements (earlywood and latewood; EW and LW). A set of Adjusted LW chronologies was also developed; in these, the relationship between LW and the preceding EW width has been removed. The ring-width chronologies exhibit moderately strong relationships with SWE records from the western Canadian Cordillera and these relationships vary in sign across the region. Distinctive regional groups are identified where chronologies exhibit same-sign correlations with SWE, in possible accordance with the elevation and characteristics of the tree-ring chronology sample sites. The EW chronologies correlate more strongly and consistently with SWE records in regions where the growth relationship with SWE is negative. The LW chronologies, and particularly the Adjusted LW chronologies, exhibit a greater number of positive correlations with the set of SWE records. Collectively these results offer valuable insights for developing a targeted sampling and/or reconstruction strategy that can exploit these different relationships with SWE to generate more robust estimates of pre-instrumental snowpack for the region.     

Revision of the Lower Cambrian brachiopod Heliomedusa Sun & Hou, 1987

Jin Yugan & Wang Huayu 1992 01 15: Revision of the Lower Cambrian brachiopod Heliomedusa Sun & Hou, 1987. Lethaia , voi. 25. pp. 35–49. Oslo. ISSN 0024–1164.
Fossils referred to Heliomedusa , from the Chiungchussu Formation of Early Cambrian age in Yunnan. are extraordinarily preserved. They were previously considered to represent jellyfish. and have been suspected more recently of being an obolellid brachiopod. A study of the morphology of this genus indicates that it is related closely lo the non-pediculate craniopsids. which occurred from Early Ordovician to Carboniferous time. The soft parts of this brachiopod. such as setae and nerves, which usually are not preserved in fossils also are described. Brachiopoda, Inarticulata, Craniapsidue, anatomy, setae, nervous system, mantle canals, Early Cambrian .