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The fossil record is the only direct source of data for studying modes (patterns) and rates of morphological change over long periods of time. Determining modes and rates is important for understanding macroevolutionary processes, but just how modes and rates vary within a taxon, and why, remain largely unaddressed. We examined patterns of morphological change in the shell of the Mesozoic marine bivalve genus Buchia over its geographic and temporal range. Most modes conformed to either random walks or stasis, and both modes and rates showed variability between locations. For example, stasis was more common in deeper marine environments, whereas random walks occurred more often at the highest paleolatitudes studied. These results indicate that the environment can play an important role in shaping patterns of evolution.

Quantitative morphometric analyses of form are widely used in palaeontology, especially for taxonomic and evolutionary research. These analyses can involve several measurements performed on hundreds or even thousands of samples. Performing measurements of size and shape on large assemblages of macro- or microfossil samples is generally infeasible or impossible with traditional instruments such as vernier calipers. Instead, digital image processing software is required to perform measurements via suitable digital images of samples. Many software packages exist for morphometric analyses but there is not much available for the integral stage of data collection, particularly for the measurement of the outlines of samples. Some software exists to automatically detect the outline of a fossil sample from a digital image. However, automatic outline detection methods may perform inadequately when samples have incomplete outlines or images contain poor contrast between the sample and staging background. Hence, a manual digitization approach may be the only option. We are not aware of any software packages that are designed specifically for efficient digital measurement of fossil assemblages with numerous samples, especially for the purposes of manual outline analysis. Throughout several previous studies, we have developed a new software tool, JMorph, that is custom-built for that task. JMorph provides the means to perform many different types of measurements, which we describe in this manuscript. We focus on JMorph's ability to rapidly and accurately digitize the outlines of fossils. JMorph is freely available from the authors. [ABSTRACT FROM AUTHOR]

One hundredSelenichnites rossendalensis(excavations), sometimes with associated trackways, have been found at Joggins Fossil Cliffs (Nova Scotia, Canada; Pennsylvanian). The majority of theSelenichnitesfound in this study contain only one lunate cast and some are distinguished by linear ridges that project behind a single lunate cast. A detailed investigation of the morphology and orientation of theseSelenichnites—attributable to xiphosurans, relatives of modern horseshoe crabs (Limulus polyphemus)—yields an understanding of xiphosuran digging behavior. Statistical analysis of 96 lunate casts from two populations ofSelenichnitesseparated by several hundred thousand years shows, with 99% confidence, that the prosomas (heads) of the younger population are smaller. Further study of the wealth ofSelenichnitesat Joggins will be useful to determine which factors control xiphosuran body-size changes and the timescale on which those changes can be seen manifest in a population. The smallest knownSelenichnites(7 mm wide) is also reported. [ABSTRACT FROM PUBLISHER]

Joggins is a famous fossil locality in Nova Scotia, Canada. Hewn by some of the world's highest tides on the Bay of Fundy, these crumbling cliffs shed light on the life and environments of the Carboniferous Coal Age, 315 million years ago. The site has been a magnet for geologists since the early nineteenth century. Charles Lyell described it as the world's best coal-bearing section and together with his colleague, William Dawson, reported amazing fossil forests and a rich terrestrial fauna. Since that golden age, the rate of new fossil discoveries has hardly diminished and in recognition of its importance, the Joggins Fossil Cliffs was awarded UNESCO World Heritage Status in 2008. Even after many years of study, it remains a tremendous thrill for us to explore this ‘classic locality’ in far-flung Nova Scotia. Each winter storm, rock fall, and tide brings with it the tantalizing possibility of new fossils and new scientific insights. In this article we share something of our excitement for Joggins and provide an up to date field guide for those wishing to unlock its secrets. [ABSTRACT FROM AUTHOR]

Naticid gastropods leave a record of predation in the form of characteristic countersunk circular boreholes. We fed bivalve prey to naticids to test whether the ratio between the inner and outer borehole diameter differed among three Recent naticid species: Euspira heros, E. lewisii and Neverita duplicata. Fossil shells from a Miocene-aged assemblage, containing naticids previously identified as E. heros and N. duplicata, were also included in our analyses. Ratios of the inner to outer diameters of naticid boreholes in bivalve shells showed that there were significant differences in borehole shape between E. heros and the two other Recent species. We found no significant differences between the ratios of E. lewisii and N. duplicata; however, a principal component analysis showed that boreholes distinctly cluster according to species. The Miocene boreholes were also distinct from the Recent, indicating that the Miocene naticids may be a separate species from E. heros and N. duplicata. We have shown that there is a species-specific component to borehole geometry. This may have important implications for palaeobiological studies, because the index of borehole functionality, previously described as an inner to outer borehole ratio of 0.5 for all naticids, may differ between species. [ABSTRACT FROM AUTHOR]