The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. 
The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. 
The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. 
The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Recent studies have shown that stable hydrogen isotope ratios (δD) in the tissues of animals often correlate with δD of local precipitation. Here we examined the relationship between δD in feathers and growing season precipitation for neotropical migrant songbirds breeding over a continent-wide isotopic gradient. δD values were determined on feathers of 140 individuals of 6 species of wild insectivorous forest songbirds (Setophaga ruticilla, Empidonax minimus, Vermivora peregrinus, Catharus ustulatus, Seiurus aurocapillus, Hylocichla mustelina) taken from 14 breeding locations across North America. The δD of feathers was strongly correlated with the δD of growing season precipitation at breeding sites across North America. As feather hydrogen is metabolically inert after growth, this relationship was then used to assess the breeding origins of wintering migrants. Deuterium values of feathers from 64 individuals representing 5 species of migrants (Helmitheros vermivorus, Wilsonia citrina, Hylocichla mustelina, Dumetella carolinensis, Seirus aurocapillus) at a wintering site in Guatemala were consistent with those predicted from the known breeding ranges of these species. This study demonstrates hydrogen isotopes may become a powerful tool for linking breeding and wintering grounds of neotropical migrant songbirds, as well as other migratory species moving between isotopically distinct regions.

Linking breeding and wintering grounds of neotropical migrant songbirds using stable hydrogen isotopic analysis of feathers.

To determine whether stable isotopes can be used for identifying the geographic origins of migratory bird populations, we examined the isotopic composition of hydrogen (deuterium, δD), carbon (δ13C), and strontium (δ87Sr) in tissues of a migratory passerine, the black-throated blue warbler (Dendroica caerulescens), throughout its breeding range in eastern North America. δD and δ13C values in feathers, which are grown in the breeding area, varied systematically along a latitudinal gradient, being highest in samples from the southern end of the species’ breeding range in Georgia and lowest in southern Canada. In addition, δD decreased from east to west across the northern part of the breeding range, from New Brunswick to Michigan. δ87Sr ratios were highest in the Appalachian Mountains, and decreased towards the west. These patterns are consistent with geographical variation in the isotopic composition of the natural environment, i.e., with that of precipitation, plants, and soils for δD, δ13C, and δ87Sr, respectively. Preliminary analyses of the δD and δ13C composition of feathers collected from warblers in their Caribbean winter grounds indicate that these individuals were mostly from northern breeding populations. Furthermore, variances in isotope ratios in samples from local areas in winter tended to be larger than those in summer, suggesting that individuals from different breeding localities may mix in winter habitats. These isotope markers, therefore, have the potential for locating the breeding origins of migratory species on their winter areas, for quantifying the degree of mixing of breeding populations on migratory and wintering sites, and for documenting other aspects of the population structure migratory animals – information needed for studies of year-round ecology of these species as well as for their conservation. Combining information from several stable isotopes will help to increase the resolution for determining the geographic origins of individuals in such highly vagile populations.

The use of isotope tracers for identifying populations of migratory birds

A great tradition in macroevolution and systematics has been the ritual squabbling between palaeontologists and molecular biologists. But, because both sides were talking past each other, they could never agree. Practitioners in both fields should play to their strengths and work together: palaeontologists can provide minimum constraints on branching points in the Tree of Life with considerable precision, and estimate the extent of unrecorded prehistory. Molecular tree analysts have remarkable modelling tools in their armoury to convert multiple minimum age constraints into meaningful dated trees. As we discuss here, work should now focus on establishing reasonable, dated trees that satisfy rigorous assessment of the available fossils and careful consideration of molecular tree methods: rocks and clocks together are an unbeatable combination. Reliably dated trees provide, for the first time, the opportunity to explore wider questions in macroevolution.

Rocks and clocks: calibrating the Tree of Life using fossils and molecules

Isotopic Study of the Biology of Modern and Fossil Vertebrates

Geologist Sir Charles Lyell made a brief visit to New Brunswick, Canada, during his 1852 visit to North America. Lyell traveled to Albert Mines during the peak of the albertite controversy, visited the Reversing Falls and graphite mines in Saint John, and took a steamboat trip up the Saint John River to Fredericton where he visited his friend, Lieutenant Governor Sir Edmund Head. Lyell’s friendship with Head likely had a long-term effect on the development of geological sciences in New Brunswick and Canada. New Brunswick newspapers followed Charles Lyell’s travels through the province and expressed hope that Lyell’s observations on the geology of New Brunswick would cast a favourable opinion on the province’s geological wealth and foster economic development.

Resume

Le geologue Sir Charles Lyell a effectue un bref arret au Nouveau-Brunswick, Canada, au cours de sa visite de 1852 en Amerique du Nord. Lyell s’est rendu a Albert Mines au moment culminant de la controverse au sujet de l’albertite; il a visite les chutes reversibles et les mines de graphite de Saint-Jean; et il a remonte en vapeur le fleuve Saint-Jean jusqu’a Fredericton, ou il a rendu visite a son ami, le lieutenant-gouverneur Sir Edmund Head. L’amitie de Lyell et Head a probablement eu un effet de longue duree sur l’essor des sciences de la terre au Nouveau-Brunswick et au Canada. Les journaux du Nouveau-Brunswick ont suivi les deplacements de Charles Lyell a l’interieur de la province; ils ont exprime l’espoir que les observations de Lyell sur la geologie du Nouveau-Brunswick engendreraient une opinion favorable sur la richesse geologique de la province et qu’elles favoriseraient le developpement economique.

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Sir Charles Lyell's travels in New Brunswick, Canada, in 1852

The occurrence of Holoptychius from southern New Brunswick, Canada, adds a new locality to eastern North America and suggests the assignment of a Late Devonian age for the Kennebecasis Formation. The formation has been considered Early Carboniferous based on a plant assemblage including Lepidodendron corrugatum and Aneimites acadica . Plant fossils likely originate from rocks overlying the Kennebecasis Formation, and are part of an unmapped westward extension of the Carboniferous Albert Formation to the Saint John area. The palaeobiogeographic implications of Holoptychius suggest the cryptic presence of a classic Late Devonian fish assemblage in southern New Brunswick and the possibility that tetrapod or near-tetrapod remains may be recovered from fossil-bearing horizons within the Kennebecasis Formation.

RESUME

La manifestation de l’Holoptychius dans le Sud du Nouveau-Brunswick, Canada, ajoute un nouvel emplacement dans l’Est de l’Amerique du Nord et permet d’attribuer l’âge du Devonien tardif a la Formation de Kennebecasis. La Formation etait consideree comme une unite du Carbonifere precoce d’apres un assemblage vegetal comprenant le Lepidodendron corrugatum et l’Aneimites acadica . Les fossiles vegetaux proviennent probablement de roches recouvrant la Formation de Kennebecasis et font partie d’un prolongement non cartographie de la Formation carbonifere d’Albert en direction ouest jusqu’a la region de Saint-Jean. Les repercussions paleobiogeographiques de la manifestation de l’Holoptychius laissent supposer la presence cryptique d’un assemblage de poissons classique du Devonien tardif dans le Sud du Nouveau-Brunswick et la possibilite d’une recuperation de restes de tetrapodes ou de quasi-tetrapodes des horizons fossiliferes a l’interieur de la Formation de Kennebecasis.

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A Late Devonian Porolepiform fish ( Holoptychius ) and the age of the Kennebecasis Formation, southern New Brunswick, Canada

Red-bed strata exposed at Lepreau Falls, southern New Brunswick, were originally interpreted as belonging to the Triassic Lepreau Formation. Poorly preserved tetrapod trackways within the strata were previously assigned to two ichnospecies; one to a new Triassic ichnospecies, Isocampe lepreauense Sarjeant and Stringer, and the other to Rhynchosauroides cf. R. franconicus (Heller). Both were attributed to reptiles. Subsequent mapping of the rocks and reassignment of the exposed strata at Lepreau Falls to the Mississippian Mabou Group prompted our re-examination of the trackway fossils. Isocampe lepreauense was described from a specimen block preserving three trackways and the original description was based on erroneous interpretation of extramorphological digit drags. Rhynchosauroides cf. R. franconicus was a tentative assignment in a letter accompanying a cast in the New Brunswick Museum, but was never formally published. We redescribe and re-interpret all the trackways as gait variations produced by temnospondyls, and most closely resemble the Carboniferous ichnotaxon Matthewichnus .

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Redescription of tetrapod trackways from the Mississippian Mabou Group, Lepreau Falls, New Brunswick, Canada

The Campbellton Formation has long been known to yield a fossil assemblage of Devonian (Emsian) fish and eurypterids at its westernmost exposure near Campbellton and Atholville, and a well described flora and early land animal fauna toward its easternmost exposure near Dalhousie Junction. Although the body fossil assemblage (paleobotany, vertebrate and invertebrate paleontology), paleoecology and paleoenvironmental context of the formation have been extensively studied, ichnofossils are rare and have not been described previously. Fossils from the vertebrate and eurypterid bearing ‘Atholville Beds’ contain a low diversity ichnofossil assemblage represented by three ichnotaxa: Monomorphichnus , ? Taenidium and Helminthoidichnites . Monomorphichnus is proposed here as being produced by the produced by the activity of the eurypterid Pterygotus anglicus .

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Ichnology of the Devonian (Emsian) Campbellton Formation, New Brunswick, Canada

George Frederic Matthews description of the Precambrian stromatolite Archaeozoon acadiense, one of the first authentic, documented Precambrian fossils, is perhaps the most overlooked of his many accomplishments. It was the first Precambrian stromatolite to receivea Linnean name and may have been the first photographed for a scientific publication. Matthew's contribution is recognized by experts in the field and inspecialized literature about stromatolites. However, it is rarely mentioned in the popular history of the search for Precambrian life which generally includes stories of Dawson's Eozooncanadense, and Walcott's Cryptozoon and Chuaria. Although the American geologist Charles Doolittle Walcott is viewed as the founder of Precambrian paleobiology, Matthew deserves acknowledgment for his early recognition of Precambrian life. A well-known figure among specialists, Matthew never attained the status ofsome of his peers and is generally not known as an important Canadian geoscientist. Employed as a customs agent and not as a paleontologist, he was never able to pursue any single field of paleontology with the resources available to his colleagues.
			
			Matthew described Archaeozoon acadiense in the Bulletin of the Natural History Society of New Brunswick. While the Bulletin had reasonable circulation among geoscientists in Matthew's day, it ceased publication in1917 and is rarely seen. Perhaps his choice of a journal to report the stromatolite contributed to his work not being widely acknowledged.
		
			Resume
			
			La description du stromatolithe precambrien Archaeozoon acadiense, l'un des premiers fossiles precambriens documentes faite par George Frederic Matthew, est peut-etre la plus meconnue de ces nombreuses realisations. Ce fut le premier stromatolithe a etre designe d'un nom linneen, et possiblement le premier dont une photographie a ete presentee dans une publication scientifique. L'oeuvre de Mathew est bien connue des experts de la specialite et bien presente dans la litterature traitant des stromatolithes. Cependant, on en fait rarement mention dans la documentation generale traitant des recherches sur la vie precambrienne et qui traitent generalement l'Eozoon canadense de Dawson ainsi que du Cryptozoon et de la Chuaria de Walcott. Quoique que l'on considere generalement le geologue etasunien Charles Doolittle Walcott comme le fondateur de la paleobiologie precambrienne, Matthew merite d'etre reconnu pour sa decouverte precoce de la vie precambrienne. Bien qu'il soit bien connu chez les specialistes, le renom de Matthew n'a jamais atteint celui de ces pairs et son nom n'apparait pas dans la liste des geologues canadiens importants. Employe au titre d'agent des douanes, et non comme paleontologue, il n'a jamais eu l'occasion comme ses collegues paleontologues qui en avaient les moyens, de se consacrer serieusement a quelque recherche paleontologique.
			
			Matthew a decrit Archaeozoon acadiense dans le Bulletin of the Natural History Society of New Brunswick. Bien que ce bulletin ait eu une diffusion appreciable dans le milieu des geologues de l'epoque de Matthew, sa publication a cesse en 1917 et il est rarement mentionne. Le medium de diffusion qu'il a choisi est peut-etre l'un des facteurs expliquant la meconnaissance de son oeuvre.

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Randall F. Miller

Papers

Sir Charles Lyell's travels in New Brunswick, Canada, in 1852

A Late Devonian Porolepiform fish ( Holoptychius ) and the age of the Kennebecasis Formation, southern New Brunswick, Canada

Redescription of tetrapod trackways from the Mississippian Mabou Group, Lepreau Falls, New Brunswick, Canada

Ichnology of the Devonian (Emsian) Campbellton Formation, New Brunswick, Canada

George Frederic Matthew's Contribution to Precambrian Paleobiology