Taphonomy plays diverse roles in paleobiology. These include assessing sample quality relevant to ecologic, biogeographic, and evolutionary questions, diagnosing the roles of various taphonomic agents, processes and circumstances in generating the sedimentary and fossil records, and reconstructing the dynamics of organic recycling over time as a part of Earth history. Major advances over the past 15 years have occurred in understanding (1) the controls on preservation, especially the ecology and biogeochemistry of soft-tissue preservation, and the dominance of bi- ological versus physical agents in the destruction of remains from all major taxonomic groups (plants, invertebrates, vertebrates); (2) scales of spatial and temporal resolution, particularly the relatively minor role of out-of-habitat transport contrasted with the major effects of time-averaging; (3) quantitative compositional fidelity; that is, the degree to which different types of assemblages reflect the species composition and abundance of source faunas and floras; and (4) large-scale var- iations through time in preservational regimes (megabiases), caused by the evolution of new bod- yplans and behavioral capabilities, and by broad-scale changes in climate, tectonics, and geochem- istry of Earth surface systems. Paleobiological questions regarding major trends in biodiversity, major extinctions and recoveries, timing of cladogenesis and rates of evolution, and the role of environmental forcing in evolution all entail issues appropriate for taphonomic analysis, and a wide range of strategies are being developed to minimize the impact of sample incompleteness and bias. These include taphonomically robust metrics of paleontologic patterns, gap analysis, equal- izing samples via rarefaction, inferences about preservation probability, isotaphonomic compari- sons, taphonomic control taxa, and modeling of artificial fossil assemblages based on modern an- alogues. All of this work is yielding a more quantitative assessment of both the positive and neg- ative aspects of paleobiological samples. Comparisons and syntheses of patterns across major groups and over a wider range of temporal and spatial scales present a challenging and exciting agenda for taphonomy in the coming decades.

/pdf/taphonomy-and-paleobiology-3vw2jipm10.pdf

Taphonomy and paleobiology

Because of fundamental differences between trace fossils and body fossils, ichnologic nomenclature is beset with difficulties. Foremost is inconsistent treatment by the International Commission on Zoological Nomenclature (lack of sanction for post-1930 names, confusion over the "rule of priority") and inadequate curation of type specimens. However, ichnologists have contributed their own problems via inadequate diagnoses and descriptions, misconceptions of ichnologic and taxonomic principles, proliferation of names and failure to engage in true monographic revisions. All these difficulties are illustrated in a thorough reevaluation of the ichnogenera Planolites Nicholson and Palaeophycus Hall. Contrary to a popular but ill-founded scheme in which these ichnogenera are differentiated simply on the presence or absence of branches, Planolites is an unlined burrow infilled with sediments having textural and fabricational characters unlike those of the host rock, whereas Palaeophycus is a lined burrow filled with sediments typically identical to those of the surrounding matrix. Planolites represents active backfilling of sediment in an ephemeral burrow constructed by a mobile deposit feeder and Palaeophycus represents passive sedimentation within an open dwelling burrow constructed by a predaceous or suspension-feeding animal. In addition to ichnological nomenclature and ethology, the ramifications are important in paleoecology, sedimentology and diagenetic studies. Currently recognized ichnospecies of Planolites include P. montanus Richter, P. beverleyensis (Billings) and P. annularis Walcott. Those of Palaeophycus include P. heberti (Saporta), P. tubularis Hall, P. striatus Hall, P. sulcatus (Miller and Dyer) and P. alternatus n. ichnosp.

Trace fossil nomenclature and the Planolites-Palaeophycus dilemma

Recent molecular phylogenies have changed our perspective on the evolution of echolocation in bats. These phylogenies suggest that certain bats with sophisticated echolocation (e.g. horseshoe bats) share a common ancestry with non-echolocating bats (e.g. Old World fruit bats). One interpretation of these trees presumes that laryngeal echolocation (calls produced in the larynx) probably evolved in the ancestor of all extant bats. Echolocation might have subsequently been lost in Old World fruit bats, only to evolve secondarily (by tongue clicking) in this family. Remarkable acoustic features such as Doppler shift compensation, whispering echolocation and nasal emission of sound each show multiple convergent origins in bats. The extensive adaptive radiation in echolocation call design is shaped largely by ecology, showing how perceptual challenges imposed by the environment can often override phylogenetic constraints.

https://www.cell.com/trends/ecology-evolution/pdf/S0169-5347(06)00021-8.pdf

The evolution of echolocation in bats

In an attempt to investigate differences between the most widely discussed hypotheses of early tetrapod relationships,
we assembled a new data matrix including 90 taxa coded for 319 cranial and postcranial characters. We
have incorporated, where possible, original observations of numerous taxa spread throughout the major tetrapod
clades. A stem-based ( total-group) definition of Tetrapoda is preferred over apomorphy- and node-based
(crown-group) definitions. This definition is operational, since it is based on a formal character analysis. A PAUP*
search using a recently implemented version of the parsimony ratchet method yields 64 shortest trees. Differences
between these trees concern: (1) the internal relationships of ai¨stopods, the three selected species of which
form a trichotomy; (2) the internal relationships of embolomeres, with Archeria crassidisca and Pholiderpeton scutigerum
collapsed in a trichotomy with a clade formed by Anthracosaurus russelli and Pholiderpeton attheyi ; (3) the internal
relationships of derived dissorophoids, with four amphibamid species forming an unresolved node with a clade
consisting of micromelerpetontids and branchiosaurids and a clade consisting of albanerpetontids plus basal
crown-group lissamphibians ; (4) the position of albenerpetontids and Eocaecilia micropoda, which form an unresolved
node with a trichotomy subtending Karaurus sharovi, Valdotriton gracilis and Triadobatrachus massinoti ; (5) the
branching pattern of derived diplocaulid nectrideans, with Batrachiderpeton reticulatum and Diceratosaurus brevirostris
collapsed in a trichotomy with a clade formed by Diplocaulus magnicornis and Diploceraspis burkei. The results of the
original parsimony run – as well as those retrieved from several other treatments of the data set ( e.g. exclusion
of postcranial and lower jaw data ; character reweighting ; reverse weighting ) – indicate a deep split of early
tetrapods between lissamphibian- and amniote-related taxa. Colosteids, Crassigyrinus, Whatcheeria and baphetids
are progressively more crownward stem-tetrapods. Caerorhachis, embolomeres, gephyrostegids, Solenodonsaurus
and seymouriamorphs are progressively more crownward stem-amniotes. Eucritta is basal to temnospondyls,
with crown-lissamphibians nested within dissorophoids. Westlothiana is basal to Lepospondyli, but evidence for
the monophyletic status of the latter is weak. Westlothiana and Lepospondyli form the sister group to diadectomorphs
and crown-group amniotes. Tuditanomorph and microbrachomorph microsaurs are successively
more closely related to a clade including proximodistally : (1) lysorophids; (2) Acherontiscus as sister taxon to
adelospondyls; (3) scincosaurids plus diplocaulids ; (4) urocordylids plus ai¨stopods. A data set employing cranial
characters only places microsaurs on the amniote stem, but forces remaining lepospondyls to appear as sister
group to colosteids on the tetrapod stem in several trees. This arrangement is not significantly worse than the tree
topology obtained from the analysis of the complete data set. The pattern of sister group relationships in the
crownward part of the temnospondyl-lissamphibian tree re-emphasizes the important role of dissorophoids in
the lissamphibian origin debate. However, no specific dissorophoid can be identified as the immediate sister taxon
to crown-group lissamphibians. The branching sequence of various stem-group amniotes reveals a coherent set
of internested character-state changes related to the acquisition of progressively more terrestrial habits in several
Permo-Carboniferous forms.

Early tetrapod relationships revisited.

Fluvial landscapes diversified markedly over the 250 million years between the Cambrian and Pennsylvanian periods. The diversification occurred in tandem with the evolution of vascular plants and expanding vegetation cover. In the absence of widespread vegetation, landscapes during the Cambrian and Ordovican periods were dominated by rivers with wide sand-beds and aeolian tracts. During the late Silurian and Devonian periods, the appearance of vascular plants with root systems was associated with the development of channelled sand-bed rivers, meandering rivers and muddy floodplains. The widespread expansion of trees by the Early Pennsylvanian marks the appearance of narrow fixed channels, some representing anabranching systems, and braided rivers with vegetated islands. We conclude that the development of roots stabilized the banks of rivers and streams. The subsequent appearance of woody debris led to log jams that promoted the rapid formation of new river channels. Our contention is supported by studies of modern fluvial systems and laboratory experiments. In turn, fluvial styles influenced plant evolution as new ecological settings developed along the fluvial systems. We suggest that terrestrial plant and landscape evolution allowed colonization by an increasingly diverse array of organisms.

/pdf/palaeozoic-landscapes-shaped-by-plant-evolution-397wr86dr6.pdf

Palaeozoic landscapes shaped by plant evolution

Handbook of zoology

In 1843–44, Sir W. E. Logan ascertained, and published in his Report* for the latter year, the occurrence of a series of beds of Devonian age in the Peninsula of Gaspe, Lower Canada, containing fossil plants, apparently of terrestrial origin, and some of them evidently in situ. Nothing was done toward the precise determination and description of these remains until 1856, when Sir William kindly permitted the writer of this paper to examine his collection, and to describe before the American Association for the Advancement of Science the most interesting specimen contained in it—a fossil trunk exhibiting a very remarkable and previously undescribed coniferous structure†. The other specimens in the collection were so fragmentary or obscure, that it was not deemed expedient to attempt their description before studying them (as all fossil plants should, when practicable, be studied) in the rocks in which they occur. With this view I visited Gaspe in the past summer, and examined the localities indicated on the plans and sections of the Geological Survey. The facts and specimens thus obtained will probably be fully described and illustrated in one of the forthcoming Decades of Canadian Fossils; and in the meantime I propose to notice some of the species observed, which appear to be of especial interest in the present state of our general knowledge of the Devonian flora. Before proceeding to these descriptions, it may be necessary to state that the deposit in which the fossils occur consists of sandstone and shale, of various colours

/pdf/on-fossil-plants-from-the-devonian-rocks-of-canada-19j7oq8i20.pdf

On Fossil Plants from the Devonian Rocks of Canada

The Fossil Plants of the Devonian and Upper Silurian Formations of Canada

Acadian Geology: The Geological Structure, Organic Remains, and Mineral Resources of Nova Scotia, New Brunswick, and Prince Edward Island

Descriptions and sections of the Coal-formation of Nova Scotia, and particularly of the cliffs called the South Joggins, have been published by Messrs. Jackson and Alger*, Mr. Brown†, Dr. Gesner‡, Sir C, Lyell §, and Mr. Logan ∥. In September last (1852) the authors of the present notice re-visited and re-examined the strata in a part of these cliffs, with a view of ascertaining what may have been the particular circumstances which favoured the preservation of so many fossil trees, at so many different levels, in an erect position; such a position being a rare and very exceptional fact in the coal strata of North America generally. We were also desirous of obtaining additional evidence on a point which is still a matter of controversy in the United States and elsewhere (although we ourselves were already satisfied with the evidence adduced by Mr. Binney¶ and others), namely, the relation of Stigmaria , as a root, to Sigillaria . We also directed our special attention to the difference of the deposits enveloping the upright trees, and those which fill the trunks themselves, forming casts within a cylinder of bark now turned to coal, the central wood of the trunk having decayed. We searched diligently for fossils in these stony casts, suspecting that organic bodies preserved in so peculiar a situation might differ from such as are buried in ordinary subaqueous strata. With this object we employed a labourer to dig out many vertical trees from the cliffs, so that we might break them

https://jgs.lyellcollection.org/content/jgsleg/9/1-2/58.full.pdf

On the Remains of a Reptile (Dendrerpeton Acadianum, Wyman and Owen) and of a Land Shell discovered in the Interior of an Erect Fossil Tree in the Coal Measures of Nova Scotia

John William Dawson

Papers

Handbook of zoology

On Fossil Plants from the Devonian Rocks of Canada

The Fossil Plants of the Devonian and Upper Silurian Formations of Canada

Acadian Geology: The Geological Structure, Organic Remains, and Mineral Resources of Nova Scotia, New Brunswick, and Prince Edward Island

On the Remains of a Reptile (Dendrerpeton Acadianum, Wyman and Owen) and of a Land Shell discovered in the Interior of an Erect Fossil Tree in the Coal Measures of Nova Scotia