Opportunistic exploitation of dinosaur dung: fossil snails in coprolites from the Upper Cretaceous Two Medicine Formation of Montana

Multiple associations of fossil snails with dinosaur coprolites demonstrate that snails and dinosaurs not only shared ancient habitats but were trophically linked via dinosaur dung. Over 130 fossil snails representing at least seven different taxa have been found on or within herbivorous dinosaur coprolites from the Upper Cretaceous Two Medicine Formation of Montana. The terrestrial snail Megomphix is the most common taxon, but three other terrestrial taxa (Prograngerella, Hendersonia and Polygyrella) and three aquatic snails (Lioplacodes, ?Viviparus and a physid) also occur in coprolites. At least 46% of the shells in the faeces are whole or nearly so, indicating that most (if not all) of the snails were not ingested by dinosaurs, but were post‐depositional visitors to the dung pats. The sizeable, moist and microbially enriched dinosaur faeces would have provided both food and roosting sites for the ancient snails, and the large number of snail–coprolite associations reflect recurring, opportunistic exploitation of dung. The terrestrial taxa in the coprolites suggest that this Late Cretaceous locality included sufficiently moist detrital or vegetative cover for snails when dinosaur dung was not present. The aquatic snails probably entered the faeces during flood events. Dinosaur dung would have provided an abundant but patchy influx of resources that was probably seasonally available in the ancient environment.     

Paleocene Thalassinidea colonization in deep-sea environment and the coprolite Palaxius osaensis n. ichnosp. in Southern Costa Rica

Palaxius osaensis n. ichnosp., a new ichnospecies of crustacean coprolite is described. The coprolite is preserved in a 200-m thick Paleocene sequence in Southern Costa Rica that is largely dominated by pillow basalts. The studied sample is part of a seamount formed in the Pacific Ocean that was accreted to the Central American isthmus during the Eocene. The absence of lava vesicles, shallow-water deposits, and detrital sediments in the section suggest that the coprolites were deposited in a deep environment during the first stage of the development of the seamount. This represents one of the deepest occurrences of Thalassinidea coprolites reported in the literature and indicates that the producers of the coprolites, presumably some shrimps, developed the aptitude to colonize abyssal environments at least since Early Tertiary. The crustacean coprolites were encountered at a site which apparently lacked a food supply, although hydrothermal processes are believed to have provided the opportunity for a chemotrophic community to develop on the deepest part of the seamount. P. osaensis n. ichnosp. is also found in Colombia in late Cretaceous shallow-water sediments that notably contain Palaxius caucaensis coprolites (Micropaleontology 41 (1995) 85-88). Occurrences of P. osaensis n. ichnosp. deposited at both shallow and deep levels may possibly be related to an aptitude of some thalassinid organisms to have developed in various biotopes during the late Cretaceous-Paleocene.     

Microbial Communities in Pre-Columbian Coprolites

The study of coprolites from earlier cultures represents a great opportunity to study an “unaltered” composition of the intestinal microbiota. To test this, pre-Columbian coprolites from two cultures, the Huecoid and Saladoid, were evaluated for the presence of DNA, proteins and lipids by cytochemical staining, human and/or dog-specific Bacteroides spp. by PCR, as well as bacteria, fungi and archaea using Terminal Restriction Fragment analyses. DNA, proteins and lipids, and human-specific Bacteroides DNA were detected in all coprolites. Multidimensional scaling analyses resulted in spatial arrangements of microbial profiles by culture, further supported by cluster analysis and ANOSIM. Differences between the microbial communities were positively correlated with culture, and SIMPER analysis indicated 68.8% dissimilarity between the Huecoid and Saladoid. Proteobacteria, Bacteroidetes and methanogens were found in all coprolite samples. Propionebacteria, Shewanella and lactic acid bacteria dominated in the Huecoid samples, while Acidobacteria, and peptococci were dominant in Saladoid samples. Yeasts, including Candida albicans and Crypotococcus spp. were found in all samples. Basidiomycetes were the most notable fungi in Huecoid samples while Ascomycetes predominated in Saladoid samples, suggesting differences in dietary habits. Our study provides an approach for the study of the microbial communities of coprolite samples from various cultures.     

Hyena hegemony: biogeography and taphonomy of Pleistocene vertebrate coprolites with description of a new mammoth coprolite ichnotaxon

Abstract

In 1822, William Buckland first recognized Pleistocene vertebrate coprolites, and they are now known from more multiple localities with a global distribution. Carnivore coprolites dominate, and there are two distinct biogeographic and taphonomic provinces for vertebrate coprolites in the Pleistocene. The Castrocopros province of North and South America is characterized by a dominance of herbivore coprolites, which are preserved almost exclusively in caves. The Hyaenacoprus province in Africa, Europe and Asia is dominated by hyena coprolites that occur mainly in caves, but also in other depositional environments. Pacific Islands may represent a third province characterized by dominant bird coprolites from caves, but the known localities are all Holocene. Mammuthocopros allenorum ichnogen. and ichnosp. nov. is a coprolite of Mammuthus columbi from Utah, USA.     

Multi‐proxy analyses of Late Cretaceous coprolites from Germany

A total of 462 coprolites from three localities exposing Upper Cretaceous deposits in the Münster Basin, northwestern Germany, have been subjected to an array of analytical techniques, with the aim of elucidating ancient trophic structures and predator–prey interactions. The phosphatic composition, frequent bone inclusions, size and morphology collectively suggest that most, if not all, coprolites were produced by carnivorous (predatory or scavenging) vertebrates. The bone inclusions further indicate that the coprolite producers preyed principally upon fish. Putative host animals include bony fish, sharks and marine reptiles – all of which have been previously recorded from the Münster Basin. The presence of borings and other traces on several coprolites implies handling by coprophagous organisms. Remains of epibionts are also common, most of which have been identified as the encrusting bivalve Atreta. Palynological analyses of both the coprolites and host rocks reveal a sparse assemblage dominated by typical Late Cretaceous dinoflagellates, and with sub‐ordinate fern spores, conifer pollen grains and angiosperm pollen grains. The dinoflagellate key taxon Exochosphaeridium cenomaniense corroborates a Cenomanian age for the Plenus Marl, from which most studied coprolites derive. The findings of this study highlight the potential of a multi‐proxy approach when it comes to unravelling the origin, composition and importance of coprolites in palaeoecosystem analyses.     

Vegetation reconstruction on the basis of pollen in Late Pleistocene hyena coprolites from San Teodoro Cave (Sicily, Italy)

Vegetation reconstruction based on pollen from coprolites of extinct spotted hyena (Crocuta crocuta spelaea, Goldfuss 1832) recovered from excavations carried out in 1998 at San Teodoro Cave (Sicily, Italy) supports previous indications of pre-Late Glacial conditions. Eight of the twelve coprolites analysed contained well-preserved pollen grains. There is a general similarity between the pollen contents from the coprolites but they show variability. They suggest a main vegetation type dominated by steppic taxa (Poaceae, Artemisia, Ephedra, Chenopodiaceae and Asteraceae) but also including arboreal taxa (Pinus and Cupressaceae). Low percentages of pollen of mesophilous woody taxa (Quercus, Betula, Abies, Alnus, Pistacia, among others) are noticeable, suggesting the existence of nearby refugia for temperate and Mediterranean vegetation. A reconstruction of the landscape, using the coprolite pollen record and other pollen records from Sicily and south Italy, shows the predominance, during the pre-Late Glacial, of a wooded steppe biome, with elements representing a variety of local environmental conditions.     

Alternative Splicing in Class V Myosins Determines Association with Rab10

Rab proteins influence vesicle trafficking pathways through the assembly of regulatory protein complexes. Previous investigations have documented that Rab11a and Rab8a can interact with the tail region of myosin Vb and regulate distinct trafficking pathways. We have now determined that a related Rab protein, Rab10, can interact with myosin Va, myosin Vb, and myosin Vc. Rab10 localized to a system of tubules and vesicles that have partially overlapping localization with Rab8a. Both Rab8a and Rab10 were mislocalized by the expression of dominant-negative myosin V tails. Interaction with Rab10 was dependent on the presence of the alternatively spliced exon D in myosin Va and myosin Vb and the homologous region in myosin Vc. Yeast two-hybrid assays and fluorescence resonance energy transfer studies confirmed that Rab10 binding to myosin V tails in vivo required the alternatively spliced exon D. In contrast to our previous work, we found that Rab11a can interact with both myosin Va and myosin Vb tails independent of their splice isoform. These results indicate that Rab GTPases regulate diverse endocytic trafficking pathways through recruitment of multiple myosin V isoforms.Eukaryotic cells are comprised of networks of highly organized membranous structures that require the efficient and timely movement of diverse intracellular proteins for proper function. Molecular motors provide the physical force needed to move these materials along microtubules and actin microfilaments. Unconventional myosin motors, such as those belonging to classes V, VI, and VII, have roles in the trafficking and recycling of membrane-bound structures in eukaryotic cells (1) and are recruited to discrete vesicle populations. Myosin VI is involved in clathrin-mediated endocytosis (2), whereas myosin VIIa participates in the proper development of stereocilia of inner ear hair cells and the transport of pigment granules in retinal pigmented epithelial cells (3, 4). Similarly, the three members of vertebrate class V myosins, myosin Va, myosin Vb, and myosin Vc, are required for the proper transport of a wide array of membrane cargoes, such as the melanosomes of pigment cells, synaptic vesicles in neurons, apical recycling endosomes in polarized epithelial cells, and bulk recycling vesicles in non-polarized cells (5).Members of the Rab family of small GTPases regulate many cellular systems, including membrane trafficking (6, 7). Certain Rab proteins associate with and regulate the function of class V myosins. Rab27a, in a complex with the adaptor protein melanophilin/Slac2-a, is required to localize myosin Va to the surface of melanin-filled pigment granules in vertebrates (8-10), whereas Rab27a and Slac2-c/MyRIP associate with both Myosin Va and myosin VIIa (3, 11). Rab11a, in a complex with its adaptor protein Rab11-FIP2, associates with myosin Vb on recycling endosomes (12-14) where the tripartite complex regulates the recycling of a variety of cargoes (15-19). In addition, Rab8a associates with both myosin Vb (20) and myosin Vc (21) as part of the non-clathrin-mediated tubular recycling system (20). Recently, Rab11a has also been shown to associate with myosin Va in the transport of AMPA receptors in dendritic spines (22), contributing to the model of myosin V regulation by multiple Rab proteins.Previous investigations have documented alternative splicing of myosin Va in a tissue-specific manner (23-28). Alternate splicing occurs in a region lying between the coiled-coil region of the neck of the motor and the globular tail region. Three exons in particular are subject to alternative splicing: exons B, D, and F (23-25). Exon F is critical for association with melanophilin/Slac2 and Rab27a (8, 9, 29, 30). Additionally, exon B is required for the interaction of myosin Va with dynein light chain 2 (DLC2) (27, 28). Currently no function for the alternatively spliced exon D has been reported. Similar to myosin Va, myosin Vb contains exons A, B, C, D, and E, whereas no exon F has yet been identified in myosin Vb (Fig. 1A). In addition, exon B in myosin Vb does not resemble the dynein light chain 2 (DLC2) binding region in myosin Va (27, 28), and therefore, it likely does not interact with DLC2. On the other hand, exon D is highly conserved among Myosin Va, myosin Vb, and myosin Vc, suggesting a common function in these molecular motors.Open in a separate windowFIGURE 1.Tissue distribution of human myosin Va and myosin Vb splice isoforms. A, schematic of the alternative exon organization in the tails of myosin Va and myosin Vb. It is known that exons B, D, and F are subject to alternative splicing in myosin Va, whereas there is only evidence that exon D is alternatively spliced in myosin Vb, which does not contain exon F. B, alignment of exon D sequences from mouse and human myosin V''s. myosin Va and myosin Vb both contain exon D (amino acids 1320-1346 of myosin Va and 1315-1340 of myosin Vb), whereas myosin Vc contains an exon D-like region (amino acids 1124-1147 of human myosin Vc) that is not known to be alternatively spliced. Alignment of the exon D regions from all three motors reveals a high degree of homology, especially in the center of the exon. Asterisks indicate amino acid identities. C, PCR-based analysis of human tissue panels reveals the alternative splicing pattern of exon D in myosin Va and myosin Vb. Primers flanking the region encoding exon D for both motors were used to amplify cDNA from human MTC™ panels (Clontech). cDNA amplified from HeLa cell RNA as well as myosin Va and myosin Vb tail constructs were used as positive controls. Variants expressing exon D (upper bands) and lacking exon D (lower bands) were visible. Per., peripheral; Pos., positive.Here we report that Rab10, a protein related to Rab8a and thought to have similar function (31-35), localizes to a system of tubules and vesicles overlapping in distribution with Rab8a in HeLa cells. Utilizing dominant-negative myosin V tail constructs, we show that Rab8a and Rab10 can interact with Myosin Va, myosin Vb, and myosin Vc in vivo. In addition, we have determined that the alternatively spliced exon D in both myosin Va and myosin Vb is required for interaction with Rab10. In contrast to our previous findings, we demonstrate that Rab11a is able to interact with both myosin Va and myosin Vb tails in an exon independent-manner. These results reveal that multiple Rab proteins potentially regulate all three class V myosin motors.     

First record of Mesozoic scroll coprolites: classification,characteristics, elemental composition and probable producers

Multiple, small, cylindrical scroll coprolites having rounded and tapering ends and pertaining to a new ichnotaxon have been recovered from the Upper Triassic Tiki Formation of India. This is the first record of scroll coprolites from the Mesozoic. Based on cross‐sectional geometry, external surface textures, and internal morphology, these coprolites are subdivided into three morphotypes. The coprolites contain several kinds of undigested food material in the form of ganoid fish scales, teeth, lower jaw and skeletal remains of various osteichthyans, chondrichthyans, archosauriforms and indeterminate reptiles. These inclusions are embedded in the groundmass separated by thin mucosal layers. The groundmass contains abundant gas vesicles, and secondarily‐filled shrinkage cracks. EDS analysis shows that the overall composition of the coprolites reflects Ca, P, C and O, suggesting calcium phosphate mineralogy, though other elements such as Fe, Mn, Al, Si are present in lesser proportions. Based on their similarity with the scrolled faeces of extant euryhaline hammerhead sharks, it is deduced that these coprolites were produced by euryhaline hybodontid sharks. At least two hybodontid taxa, Lonchidion and Pristrisodus, show high prevalence in the Tiki vertebrate fauna, suggesting that these were the possible producers. As the coprolite inclusions contain remains of other aquatic animals, these carnivorous hybodonts constituted the dominant predators of the Tiki aquatic ecosystem.     

Coprolite morphotypes from the Upper Cretaceous of Sweden: novel views on an ancient ecosystem and implications for coprolite taphonomy

Eriksson, M.E., Lindgren, J., Chin, K. & Månsby, U. 2011: Coprolite morphotypes from the Upper Cretaceous of Sweden: novel views on an ancient ecosystem and implications for coprolite taphonomy. Lethaia, Vol. 44, pp. 455–468. Coprolites (fossilized faeces) are common, yet previously unreported, elements in the Campanian (Upper Cretaceous) shallow‐marine strata of Åsen, southern Sweden. They are associated with a diverse vertebrate fauna and comprise at least seven different morphotypes that suggest a variety of source animals. Their faecal origin is corroborated by several lines of evidence, including chemical composition (primarily calcium phosphate), external morphology and nature of the inclusions. Preservation in a fossil coquina, interpreted as a taphocoenosis, suggests early lithification promoted by rapid entombment. This would have prevented disintegration of the faecal matter and facilitated transportation and introduction to the host sediment. The coprofabrics can generally be correlated to specific gross morphologies, supporting a morphology‐determined coprolite classification. Moreover, having been deposited under presumably comparable taphonomic conditions, variations in coprofabrics infer differences in diet and/or digestive efficiency of the host animal. Size and morphology of the coprolites imply that most, if not all, were produced by vertebrates and the largest specimens infer a host animal of considerable size. Two spiralled coprolite morphotypes yield bone fragments and scales of bony fish, suggesting that the producers were piscivorous sharks. Other coprolites contain inclusions interpreted as the remains of shelled invertebrates, thus indicating that they may have derived from durophagous predators and/or scavengers. The occurrence of small scrapes, tracks and traces on several specimens suggest manipulation of the faeces by other (presumably coprophagous) organisms after deposition. The collective data from the Åsen coprolites provide new insights into a shallow‐water Late Cretaceous marine ecosystem hitherto known solely from body fossils. □ Coprolites, vertebrates, coprofabrics, taphonomy, trophic levels, Upper Cretaceous, Sweden.     

First paleoparasitological study of micromammal coprolites from the holocene of the Somuncurá Plateau Protected Natural Area (Patagonia Argentina)

The Somuncurá Plateau is a Protected Natural Area located in the middle of the northern extra-Andean arid Patagonia. Inhabited by at least 20 small mammal species, is the place with the uppermost species richness in Patagonia. The aim of this study was to examine the parasite remains from micromammal coprolites collected in association with a bone sequence recovered at the east of the Somuncurá Plateau (site “Alero Las Lechuzas”). Coprolites came from the four temporal units previously defined: unit I (4790?±?100?yrs. ¹⁴C B.P.), unit II, unit III (7840?±?120?yrs. ¹⁴C B.P.) and unit IV. Each coprolite was processed, rehydrated, homogenized, processed by spontaneous sedimentation and examined using a light microscope. Coprolites and eggs were described, measured and photographed. Samples were positive for two nematode species: Helminthoxys caudatus Freitas, Lent & Almeida, 1937 (Oxyurida, Oxyuridae) and Trichuris spp. (Trichinellida: Trichuridae). This is the first paleoparasitological study developed for the Somuncurá Plateau Protected Area. Moreover, this is the first time that the genus Helminthoxys is reported from ancient times worldwide. Coprolites were attributed to the mountain cavy Microcavia australis (Rodentia, Caviidae).The presence of H. caudatus for the Middle Holocene of northern Patagonia contributes to the study of the history of the histricomorphs and pinworms relationships.     

Footprint on a coprolite: A rarity from the Eocene of Vietnam

A rare ichnological example of a crocodilian footprint on an Eocene crocodilian coprolite has been discovered. The enigmatic specimen, measuring 4 cm in length, was found among 100 coprolites at the Na Duong coal mine in Lang Son province, northern Vietnam. Almost all the discovered coprolites were ascribed to a potential crocodilian producer, suggesting the existence of an ancient lacustrine environment. Furthermore, neoichnological analyses of extant crocodilian footprints also corroborate the inference of a crocodilian as the producer of the footprint. We concluded that the 4-cm-long Na Duong fingerprints most likely belonged to a 2-m-long crocodilian whose IV or V finger of the right manus might have made the fingerprints. Since no other records of foot traces or trackways were identified during the fieldwork in the fall of 2018, the Na Duong fossil site should be investigated for further ichnofossil analysis.     

The ichnogenous<Emphasis Type="Italic">Palaxius</Emphasis> (crustacean coprolite) and description of<Emphasis Type="Italic">P. hydranensis</Emphasis> n. sp. from the Upper Triassic (Norian part of “Pantokrator” limestone) of Hydra (Greece)

The fossil coprolite ichnogenusPalaxius is known with 22 species from the Permian up to the Tertiary. The diagnostic characteristics and the stratigraphie range of all species is given in this paper. The ichnogenusAgantaxia Kristan-Tollmann is a younger synonym of the ichnogenusPalaxius. The new crustacean coprolitePalaxius hydranensis n. sp. is described from the reef limestones of Norian part of “Pantokrator” limestone of the Island Hydra (Greece). This is the first report of coprolites from Hydra. The organism association of coprolite bearing limestone is mentioned.      

Insights about echinostomiasis by paleomolecular diagnosis

Echinostomiasis is a zoonosis caused by intestinal trematodes and transmitted by the ingestion of mollusks, crustaceans, fish, amphibians, and reptiles, either raw or poorly cooked. Today human infection is endemic in Southeast Asia and the Far East, but has been reported more recently in other regions of the world. Interestingly eggs identified as Echinostoma sp. were found in coprolites from a mummified body human in Brazil, dated 560 ± 40 BP (before present). However, the specific diagnosis based on morphology of the eggs has not been resolved at the species level. As a follow-up to the previous finding, the current study now aims to standardize the methodology for molecular diagnosis and apply it to the coprolite, using current Echinostoma paraensei-positive feces as the reference, and also the same fecal material dried in a stove as an experimental coprolite model. Isolated eggs of E. paraensei and adult worm were included to verify the sensibility and as positive control, respectively. An adult worm of E. luisreyi was used for comparison. PCR using primers in-house for ITS1 region (126 bp) and cox1 (123 bp) of Echinostoma spp. and subsequent nucleotide sequencing were performed. This is the first molecular paleoparasitological diagnosis for echinostomiasis. The methodology was able to amplify specific DNA fragments for the genus Echinostoma sp. in all samples: adult worm, feces, and a single egg of the parasite, in both the experimental coprolite and archaeological sample. Additionally we observed that ancient DNA can also be retrieved without rehydrating the material. The nucleotide sequences from E. paraensei and E. luisreyi are very similar in the fragment analyzed that difficult the differentiation these species, but DNA sequence analysis recovered in the parasite found in the mummy showed more similarity with the species E. paraensei.     

5''-Halogeno-2'',3''-cyclic sulphite isomers in the preparation of 5''-halogeno nucleosides. Synthesis of 5''-deoxyuridine and 5''-deoxy-5-fluorouridine.

When uridine (Ia) is reacted with thionyl chloride in hexamethylphosphoric triamide a mixture of isomeric 5'-chloro-2',3'-sulphites is formed, which can be separated to individual epimers IIa and IIIa, in 45% and 15% yields, respectively. Analogously, crystalline epimers IIb (37%) and IIIb (17%) can be obtained from 5-fluorouridine (Ib). Both isomers IIa, IIIa (or IIb, IIIb) afford a single 5'-chloro derivative IVa (or IVb, respectively) if treated with 0.1N sodium methoxide. From the mixture of sulphites IIa and IIIa (or IIb and IIIb) crystalline 5'-chlorouridine IVa is formed in 84.5% yield, calculated per starting uridine Ia (or crystalline 5'-chloro-5-fluorouridine IVb, 85.5% per starting 5-fluorouridine Ib, respectively). On reduction of 5'-chlorouridine IVa with tributyltin hydride 5'-deoxyuridine (Va) is formed in 79% yield. During the reduction of 5'-chloro-5-fluoro derivative IVb to 5'-deoxy-5-fluorouridine (Vb, 57%) a partial reductive elimination of 5-fluorine takes place under formation of 5'-deoxyuridine (Va, 9%).     

Gar-Bitten Coprolite From South Carolina,USA

Coprolites can preserve a wide range of biogenic components. Of all the coprolites known from the fossil record, hitherto only two are known to preserve vertebrate tooth impressions (i.e., those of chondrichthyans). Here, a coprolite, from a thick lag deposit that includes a mixture of late Cretaceous, early Paleocene, and Plio-Pleistocene taxa at Clapp Creek in Kingstree, Williamsburg County, South Carolina, USA, preserves bite marks most consistent with having been made by a gar, Lepisosteus sp. (Lepisosteidae, Actinopterygii). This is the first-known coprolite to preserve actinopterygian tooth/bite marks. Aborted coprophagy seems unlikely; an accidental or serendipitous strike more likely describes the origin of the score marks over the surface of the coprolite. This coprolite also preserves small paired striations interpreted as evidence of coprophagy by an unknown organism.     

New data on synecology of Vyazniki terrestrial community (Terminal Permian,Central Russia)

New materials from terminal Permian localities of the Vyazniki Faunal Assemblage from the eastern Vladimir Region, including a tooth of the proterosuchid Archosaurus rossicus Tatarinov, 1960, which is recorded for the first time in a coprolite, are described. New data on tetrapod coprolites allow a more reliable reconstruction of trophic relationships and reorganization of the trophic structure of this terrestrial community. Interactions of the higher-rank consumers therocephals and early proterosuchid archosaurs were not restricted to competition for food resources, but also included preying of adult representatives of one taxon on juveniles of the other.     

Canid Coprolites from the Late Pleistocene of Hidalgo,Central Mexico: Importance for the Carnivore Record of North America

We present the first reported occurrence of canid coprolites from the late Pleistocene of central Mexico. The sample consists of five associated coprolites recovered from Quaternary deposits that crop out in southeastern Hidalgo, central Mexico. The material shows several of the typical features of canid feces, including elongated cylindrical shape, uncommon and nondistinct constrictions, and one tapered end. The coprolites are similar in size to feces of North American foxes, such as Vulpes macrotis, V. lagopus, V. vulpes, and Urocyon cinereoargenteus; likewise, their size might be comparable to those of the Pleistocene canid Canis cedazoensis. The content of the studied coprolites consists of numerous teeth and bone fragments referable to the pocket gophers Pappogeomys or Cratogeomys. The coprolite content is related to a mostly carnivorous diet comparable to that of C. cedazoensis, wolves (Canis lupus, C. rufus, and C. dirus), and some foxes (V. macrotis and V. velox). As a result, it is proposed that the potential trace maker of the coprolites could be a form similar to a carnivorous fox or a small dog. These trace fossils represent the first indirect evidence of canids in the late Pleistocene of Hidalgo and provide additional information regarding the geographic distribution of the Canidae in temperate areas of North America that now are part of central Mexico during the second half of the Pleistocene.     

Range of Experimental Dinosaur (Hypsilophodon foxii) Footprints Due to Variation in Sand Consistency: How Wet Was the Track?

The laboratory-controlled simulations of dinosaur footprints in this study revealed characteristic track features that could be used to identify the consistency of sand substrates and provide an insight into the paleoenvironment. A model foot of Hypsilophodon foxii was indented into three sands of four different moisture (= water) contents. The two intermediate moist states were characterized by shallow tridactyl impressions, in which only digits II–IV were impressed, showing details of padding and claws. Where the foot penetrated more deeply, in the dry and saturated states, the hallux and heel were also impressed; in these cases, the foot detail was not preserved accurately and track morphology deviated significantly from that of the foot. Dry sand tracks were characterized by the outward and upward movement of sediment and tracks in saturated sand by mainly downward displacement. The finer-grained saturated sand was also associated with liquefaction and closure of digit imprints. Tracks from the Middle Jurassic Cleveland Basin of Yorkshire showed features of the saturated state. The range of experimental track morphotypes formed by one foot highlighted the difficulties in assigning a print type to a particular trackmaker and the importance of excluding preservational variants from ichnotaxonomic studies.     

Response and resilience of soil biocrust bacterial communities to chronic physical disturbance in arid shrublands

The impact of 10 years of annual foot trampling on soil biocrusts was examined in replicated field experiments at three cold desert sites of the Colorado Plateau, USA. Trampling detrimentally impacted lichens and mosses, and the keystone cyanobacterium, Microcoleus vaginatus, resulting in increased soil erosion and reduced C and N concentrations in surface soils. Trampled biocrusts contained approximately half as much extractable DNA and 20–52% less chlorophyll a when compared with intact biocrusts at each site. Two of the three sites also showed a decline in scytonemin-containing, diazotrophic cyanobacteria in trampled biocrusts. 16S rRNA gene sequence and terminal restriction fragment length polymorphism (T-RFLP) analyses of soil bacteria from untrampled and trampled biocrusts demonstrated a reduced proportion (23–65% reduction) of M. vaginatus and other Cyanobacteria in trampled plots. In parallel, other soil bacterial species that are natural residents of biocrusts, specifically members of the Actinobacteria, Chloroflexi and Bacteroidetes, became more readily detected in trampled than in untrampled biocrusts. Replicate 16S rRNA T-RFLP profiles from trampled biocrusts at all three sites contained significantly more fragments (n=17) than those of untrampled biocrusts (n⩽6) and exhibited much higher variability among field replicates, indicating transition to an unstable disturbed state. Despite the dramatic negative impacts of trampling on biocrust physical structure and composition, M. vaginatus could still be detected in surface soils after 10 years of annual trampling, suggesting the potential for biocrust re-formation over time. Physical damage of biocrusts, in concert with changing temperature and precipitation patterns, has potential to alter performance of dryland ecosystems for decades.     

Remarks on the classification of fossil anomuran coprolites

The fossil anomuran coprolite form-genera are defined by the type of the cross section of the longitudinal canals which pierce the fecal pellet. Arrangement and number of longitudinal canals within the 2 bilaterally symmetric groups of canals are the principal elements for the definition of form-species of anomuran coprolites. To-date the 4 thalassinid form-generaFavreina Brönnimann, 1955,Palaxius Brönnimann & Norton, 1960,Helicerina Brönnimann & Masse, 1968, andParafavreina Brönnimann, Caron & Zaninetti, 1972, and the single galatheid form-genusThoronetia Brönnimann, Caron & Zaninetti, 1972, have been established.