Burrow Systems Research Articles

Sulcolithos variabilis igen. et isp. nov.: grooves on firm and hard bedding surfaces

The trace fossil Sulcolithos variabilis igen. et isp. nov. is described from the Middle Triassic (Ladinian) Muschelkalk Group of Germany. The groove-like structures occur on the surface of limestone beds that provided firm to hard substrate to the burrowing and/or boring organisms. The grooves have an elongate, straight or curved course and can be compound with subsurface burrow systems of Balanoglossites. Similar trace fossils have been reported from Late Ediacaran to Holocene deposits, and seem to be prevalent in Ordovician, Triassic and Jurassic time. Based on indirect evidence (e.g. morphology, interrelationship with Balanoglossites, substrate property), S. variabilis is attributed to the combined burrowing and boring activity of polychaetes. This interpretation is supported by direct evidence, such as the occurrence of exceptionally preserved polychaete remains in the traces, both in the Triassic material from Germany and the Ordovician specimens from Anticosti Island, Canada. However, morphologically similar traces in soft and firm substrate can also be produced by other organisms (e.g. bivalves) and represent behavioural convergence.

Spatial and seasonal variation in occupation and abundance of common vole burrows in highly disturbed agricultural ecosystems

Understanding how species respond to disturbance in human-modified ecosytems is critical for management and conservation of biodiversity in the Anthropocene. In agroecosystems, human disturbances severely modify the habitat of species, particularly for those that live in burrows. The common vole Microtus arvalis (Pallas, 1778) is a semi-fossorial microtine, which often exhibits large abundance fluctuations, becoming an agricultural pest in peak years. We evaluated how both agrarian disturbances (via types of crop and their management) and landscape heterogeneity influenced the abundance of common vole burrow systems along a yearly cycle, at the field and landscape scales. We seasonally recorded the number of burrows and their recent occupation in circular plots of 200-m radius including different types of crops in intensified agrarian landscapes in NW Spain. Our results showed a marked seasonal and spatial pattern in both total abundance and abundance of occupied burrows. After a population peak year, only 31% of burrows were occupied across the year (from 41% in spring–summer to 12% in autumn). The crop type and its management in relation to soil disturbance were the main factors driving seasonal and spatial dynamics of burrow abundance at the field and landscape scale. Alfalfa fields held the highest abundance of both total and occupied burrow systems across the year, while fields of traditional-tilled cereal retained the lowest. As a result, at the landscape scale, plots with a greater surface devoted to traditional cereal crops maintained a lower relative number of burrow systems. Regarding the landscape structural heterogeneity, plots with longer length of field margins and lower area of watercourses maintained higher abundance of burrow systems. An adequate landscape-scale planning of crop types, agricultural practices, and distribution of non-crop habitats could be a promising sustainable method to reduce the risk of crop-damaging vole plagues.

Broad‐headed spiny rats (Clyomys laticeps) as ecosystem engineers in the Brazilian savannah

AbstractSoil disturbances promoted by the construction of subterranean systems are a classic example of ecosystem engineering. The broad‐headed spiny rat Clyomys laticeps caches seeds in subterranean systems excavated and occupied by its individuals, thus acting as potential ecosystem engineers in the Brazilian savannah. However, the effects of their activities on soil nutrient content and animal communities are still unknown. Here, we assessed the role of C. laticeps as an allogenic ecosystem engineer in a shrub savannah site. Our results demonstrated that C. laticeps subterranean systems, which contain three to seven burrow openings, provide a stable microclimate with lower temperatures and higher humidity than the outside environment, thus providing suitable habitat for several species. However, we found few animals associated with burrow systems, although previous studies recorded snakes, frogs, lizards and rodents using burrows as shelter. Both burrow architecture and methodological issues might explain the lack of a richer fauna using C. laticeps burrows. Arthropod abundance and diversity were similar between sites close to and away from C. laticeps burrow openings. Finally, mounds of soil accumulated surrounding burrow openings presented higher nutrient content (K, Ca, Mg) than soils collected inside burrow openings and control sites. Overall, our results support the hypothesis that C. laticeps acts as an ecosystem engineer, especially by modulating soil nutrient availability. Soil enrichment provided by C. laticeps burrowing activity may be particularly important in the Cerrado, due to low nutrient availability of soils and the contribution of edaphic factors on plant population dynamics in this biome, although future studies should focus on this issue. Given the accelerated habitat loss in the Cerrado and its effect on population decline of mammals, future studies should uncover the magnitude of engineering effects played by C. laticeps and pinpoint conservation actions to maintain their populations and their functional roles on ecosystems.

Living with roommates in a shared den: Spatial and temporal segregation among semifossorial mammals

Positive interspecific interactions in animal communities (i.e. den sharing) have long been overlooked in animal ecology. The assessment of spatiotemporal overlap among species living within the same burrow system is paramount to explain their strategies of interspecific coexistence. We studied spatiotemporal behavioural patterns of coexistence among four den-sharing mammal species (i.e. the crested porcupine Hystrix cristata, the Eurasian badger Meles meles, the red fox Vulpes vulpes and the European pine marten Martes martes), inhabiting a hilly area of central Italy. Intensive camera trapping (September 2015-September 2018) was used to estimate the interspecific overlap of both temporal and spatial activity patterns for all species combinations. An extensive nocturnal temporal overlap was recorded among all the species, except the diurnal pine marten. However, crested porcupines were mostly active in the darkest nights, whereas bright moonlight enhanced the hunting success of the red fox. Activity of badgers was limited in bright nights only during cold months, when predation pressure and poaching risk were the highest. Crested porcupines avoided spatial sharing outside the den with both nocturnal carnivores, particularly during the winter, when its cubs are in the den. Overlap in ranging areas and activity rhythms between the red fox and the Eurasian badger may be promoted by a remarkable food niche partitioning. Conversely, spatiotemporal overlap between red foxes and pine martens suggested a significant interspecific spatial partitioning, due to the overlap in feeding habits. Den-sharing represents a form of positive interspecific interaction which may limit energy waste and increase local species diversity and densities. Species using the same burrow system may show both spatial and temporal niche partitioning throughout the year, thus allowing a non-competitive coexistence.

A new species of Mesostylus (Decapoda, Axiidea, Callianassidae) – A peep into the private life of a Late Cretaceous burrowing shrimp

Numerous individuals of a ghost shrimp, here described as a new species, Mesostylus pervesleri, are recorded from the lower Maastrichtian Piesting Formation at Muthmannsdorf in Lower Austria. The accompanying molluscan fauna comprises bivalves, gastropods and cephalopods that are indicative of a low-energy, shallow-marine environment with normal salinity. The ghost shrimp body fossils are associated with two types of trace fossil; one of these is here interpreted as the remains of a callianassid burrow system, a conclusion supported by the in-situ preservation of body fossils within the burrows. Occasionally more than one individual is preserved in the same burrow structure; specimen orientation suggests that these represent moults. The presumed moults from the same burrow structure apparently do not belong to the same individual, which supports the idea that more animals shared the same burrow system at any time. Gregarious behaviour amongst representatives of the extinct genus Mesostylus is postulated on the basis of this find, and a similar one from the Upper Cretaceous of Germany. The diagnosis of the genus Mesostylus is here emended to include characters of the pleon and telson as documented not only in the new material from Muthmannsdorf but, more importantly, also in the type species, Mesostylus faujasi. The type material of Protocallianassa sarysuensis from the Coniacian of Azerbaijan is reinterpreted as representing the minor chelae of a co-occurring species, Protocallianassa caucasica; together they are here referred to as Mesostylus caucasicus, which brings the number of species belonging to the genus to four.

Contourite facies model: Improving contourite characterization based on the ichnological analysis

The calcareous contourites from the Late Oligocene and Early Miocene in the Petra Tou Romiou type section (southern Cyprus) have been studied in detail, being regarded as outstanding examples of fossil bioclastic contourites and representative of the standard facies model of contourite bigradational sequence. These bigradational sequences of sand-dominated contourites consists of whitish calcarenite beds with wavy layering in the middle portion of the sequence. Gradual alternations of whitish and greenish calcilutites appear above and below these calcarenites. The internal wavy layering is composed by compacted interlayers and non-compacted interstratified layers. In the present study, an in-depth ichnological analysis of the bigradational sequence has been conducted, focusing on ichnological features such as length, shape, diameter, and orientation of individual burrow segments, the configuration of burrow systems, as well as external features, fill material, and finally taphonomy. Trace-fossil assemblages differ, containing Planolites isp., Chondrites isp., and ?Thalassinoides isp. at the compacted interlayers, and non-compacted layers bearing only Planolites structures. The compacted interlayer structures are flattened and elliptical, containing similar fill material as the calcilutite host sediment, though lighter in color. In the non-compacted layers, Planolites are near un-deformed, being cylindrical and tubular, with circular to sub-circular cross-sections. These are located mainly at the base or occupy the entire layer, locally showing longitudinal striae (Planolites reinecki Książiewicz), and filled with calcarenite material. The different trace-fossil assemblages in the compacted layers and non-compacted interlayers, varying in fill material, evidence an original primary differentiation, presumably indicative of fluctuating paleoenvironmental conditions. In consecutive non-compacted layers, the distribution of Planolites is separated by compacted interlayers. This indicates that the middle portion of the contourite type facies, with internal wavy layering, underwent a multiphase deposition. In the non-compacted layers, the almost undeformed Planolites, marked by striae, is consistent with a higher substrate consistency, which is interpreted as being associated with sedimentary condensation or omission, immediately before the next compacted interlayers were deposited. This evidence clearly supports the contention that sedimentary processes governing contourite deposition were intermittent rather than continuous, as traditionally proposed. These findings raise basic questions regarding the bottom current processes, and consequent bedform development in these deep-marine environments.

Case Histories of GPR for Animal Burrows Mapping and Geometry.

Ground-penetrating radar (GPR) has a wide range of applications, from geologic mapping to concrete inspection. A recently emerging GPR application is deployment in biological investigations as a non-invasive technique. Geophysical mapping of features such as tree roots and turtle burrows has proved valuable for the understanding of these subsurface systems for ecological, environmental, or engineering purposes. Four case histories of GPR investigations pertaining to animal burrows are described: cutter ants in Brazil, groundhogs in Michigan, and groundhogs, and burrowing bees in Pennsylvania. Cutter ants (Atta spp.) in Amazonian Brazil are known to construct burrows of nearly the same dimensions as groundhogs as they excavate galleries up to 7 m deep for leaf storage. Cutter ant burrows are hazardous to heavy equipment and may also cause loss of mud circulation during rotary drilling. Groundhogs (Marmota monax), found throughout the United States, cause unseen hazards, particularly for equestrian facilities where a sudden collapse can cause severe injuries to both horse and rider. Burrowing bees (Colletes inaequalis) are common in the northeastern United States. The size of the bee burrows is significantly smaller than that of the cutter ants and the groundhogs. The data for these surveys were collected over a twenty-year span, crossing several generations of survey equipment and processing techniques. Together, these four case histories highlight the historic and current capabilities of GPR systems applied to mapping subsurface burrow systems. These examples demonstrate the important impact near surface heterogeneities have in altering ecological, environmental, or engineering systems and the utility of GPR for mapping such heterogeneities.

Brain atlas of the African mole-rat Fukomys anselli.

African mole‐rats are subterranean rodents that spend their whole life in underground burrow systems. They show a range of morphological and physiological adaptations to their ecotope, for instance severely reduced eyes and specialized somatosensory, olfactory, and auditory systems. These adaptations are also reflected in the accessory sensory pathways in the brain that process the input coming from the sensory organs. So far, a brain atlas was available only for the naked mole‐rat (Heterocephalus glaber). The Ansell's mole‐rat (Fukomys anselli) has been the subject of many investigations in various disciplines (ethology, sensory physiology, and anatomy) including magnetic orientation. It is therefore surprising that an atlas of the brain of this species was not available so far. Here, we present a comprehensive atlas of the Ansell's mole‐rat brain based on Nissl and Klüver‐Barrera stained sections. We identify and label 375 brain regions and discuss selected differences from the brain of the closely related naked mole‐rat as well as from epigeic mammals (rat), with a particular focus on the auditory brainstem. This atlas can serve as a reference for future neuroanatomical investigations of subterranean mammals.

Work behaviour and biting performance in the cooperative breeding Micklem’s mole-rat Fukomys micklemi (Bathyergidae, Rodentia)

For the first time social organisation was studied in a family of wild-caught Micklem’s mole-rat Fukomys micklemi (Sekute cytotype 2n = 56) from Zambia. Fukomys mole-rats are chisel-tooth diggers, using the incisors to excavate burrow systems. Data were collected on work behaviour and analysed against morphological variables and biting performance, the latter especially with regards to the work related to the use of the feeding apparatus. In accordance with patterns observed in several other species of African mole-rats (Bathyergidae, Rodentia), the data support the idea that Micklem’s mole-rats are cooperative breeders, exhibiting a highly developed social system. Apart from a reproductive skew in Micklem’s mole-rats, we document a skew in the labour effort, with breeders being among the least active animals. Although there was considerable variation across helpers in the amount and the type of work performed, no apparent caste polyethism could be observed. We argue that taken together with evidence from various other recent studies the notion of a caste system represents a subjective subdivision in African mole-rats. Though biting performance was strongly correlated with morphological (size i.e. body mass, head length and head height) variables, we found no clear significant relation between the extent of an individual’s commitment to work and maximum bite force.

Energetics and thermal adaptation in semifossorial pine-voles Microtus lusitanicus and Microtus duodecimcostatus.

Rodents colonising subterranean environments have developed several morphological, physiological and behaviour traits that promote the success of individuals in such demanding conditions. Resting metabolic rate, thermoregulation capacity and daily energy expenditure were analysed in two semi-fossorial pine-vole species Microtus lusitanicus and Microtus duodecimcostatus inhabiting distinct areas of the Iberian Peninsula. Individuals capture location varied in habitat and soil features, allowing the comparison of energetic parameters with ecological characteristics, that can help explain the use of the subterranean environment and dependence of the burrow system. Results showed that M. duodecimcostatus has lower mass independent resting metabolic rate when compared with M. lusitanicus, which may be a response to environmental features of their habitat, such as dryer soils and lower water availability. Thermal conductance increased with body mass and was dependent on the ambient temperature. No significant differences were observed in the daily energy expenditure, but water economy data demonstrated the influence of the water available in the habitat on the energetics of voles. These species may rely on behavioural adaptations and seasonal use of burrows to cope with thermal challenges of subterranean activity and soil constraints. We found strong evidence that M. lusitanicus is able to use torpor as a response to low ambient temperatures which is a new observation among Arvicolines.

Functional-trait ecology of the plateau pika Ochotona curzoniae in the Qinghai-Tibetan Plateau ecosystem.

Understanding a species' functional traits allows for a directed and productive perspective on the role a species plays in nature, and thus its relative importance to conservation planning. The functional-trait ecology of the plateau pika Ochotona curzoniae is examined to better understand the resilience and sustainability of the high alpine grasslands of the Qinghai-Tibetan Plateau (QTP). The key functional traits of plateau pikas are their abundance and behavior of digging extensive burrow systems. Plateau pikas have been poisoned over a significant part of their original geographic distribution across the QTP, allowing comparison of ecological communities with and without pikas. Nearly all mammalian and avian carnivores, most of which are obligate predators on pikas, have been lost in regions where pikas have been poisoned. Most endemic birds on the QTP nest in pika burrows; when pikas are poisoned, burrows collapse, and these birds are greatly reduced in number. Due to the biopedturbation resulting from their burrows, regional plant species richness is higher in areas with pikas than without. The presence of pika burrows allows higher rates of infiltration during heavy monsoon rains compared to poisoned areas, possibly mitigating runoff and the potential for serious downslope erosion and flooding. Thus, the functional traits of plateau pikas enhance native biodiversity and other important ecosystem functions; these traits are irreplaceable. As plateau pikas are not natural colonizers, active re-introduction programs are needed to restore pikas to areas from which they have been poisoned to restore the important functional ecological traits of pikas.

Relatedness and spatial distance modulate intergroup interactions: experimental evidence from a social rodent.

Kin selection theory predicts that individuals should generally behave less aggressively or more amicably towards relatives than nonkin. However, how individuals treat conspecifics depends on genetic relatedness but also on the ecological context, which influences the benefits and costs of their interactions. In this study, we used microsatellite DNA markers and behavioral tests to examine the influence of kinship and proximity on the social behavior of Mongolian gerbils Meriones unguiculatus living in different social groups, and whether these effects varied with sex and season. We recorded the duration of 4 behavioral categories (investigative, neutral, amicable, and agonistic) during a 10-min pairwise test. We found that genetic relatedness had significant effects on the duration of investigative, neutral, and amicable behavior, but not on agonistic behavior. We also found significant interaction effects of relatedness and distance between burrow systems (i.e., spatial distance) on investigative, neutral, and amicable behavior, which suggests that the effects of kinship on social behavior were restricted by spatial proximity. The interaction effect between sex and relatedness on amicable behavior showed that male gerbils became more intimate with individuals of the same sex that had higher pairwise relatedness than females. Furthermore, both male and female gerbils enhanced their aggression during the food-hoarding season, but the intensity of these changes was significantly higher in females. Overall, our results suggest that the effects of kinship and spatial proximity on social behavior exhibit sexual or seasonal patterns, thereby implying ecological context-dependent responses to out-group individuals in Mongolian gerbils.

Do subterranean mammals use the Earth's magnetic field as a heading indicator to dig straight tunnels?

Subterranean rodents are able to dig long straight tunnels. Keeping the course of such “runways” is important in the context of optimal foraging strategies and natal or mating dispersal. These tunnels are built in the course of a long time, and in social species, by several animals. Although the ability to keep the course of digging has already been described in the 1950s, its proximate mechanism could still not be satisfactorily explained. Here, we analyzed the directional orientation of 68 burrow systems in five subterranean rodent species (Fukomys anselli, F. mechowii, Heliophobius argenteocinereus, Spalax galili, and Ctenomys talarum) on the base of detailed maps of burrow systems charted within the framework of other studies and provided to us. The directional orientation of the vast majority of all evaluated burrow systems on the individual level (94%) showed a significant deviation from a random distribution. The second order statistics (averaging mean vectors of all the studied burrow systems of a respective species) revealed significant deviations from random distribution with a prevalence of north–south (H. argenteocinereus), NNW–SSE (C. talarum), and NE–SW (Fukomys mole-rats) oriented tunnels. Burrow systems of S. galili were randomly oriented. We suggest that the Earth’s magnetic field acts as a common heading indicator, facilitating to keep the course of digging. This study provides a field test and further evidence for magnetoreception and its biological meaning in subterranean mammals. Furthermore, it lays the foundation for future field experiments.

Experimental Combat-Stress Model in Rats: Histological Examination of Effects on Amelogenesis— A Possible Measure of Diminished Vagal Tone Episodes

Developmental defects of enamel-stress histomarker rings (accentuated striae) may be a potential measure of diminished vagal tone in research on extreme stress such as exposure to combat. To develop an animal model of this measure, we examined the enamel of rat incisors which erupt continuously. We examined incisors from 15 stressed-colony rats and 7 control-group rats for these histomarkers using the Visible Burrow System (VBS). VBS was developed to study combat stress in rats. No stress rings were found in any of the rat incisors examined. In contrast to humans, rats have likely evolved to prioritize incisor strength during combat stress. Studies of amelogenesis during combat stress in other rodents with continuouly growing incisors are warranted. Laboratory animals such as rabbits or marmosets may be especially suitable, since they less frequently use their incisors for self-defense.

Palaeoecological Analysis of Trace Fossil Sinusichnus sinuosus from the Middle Triassic Guanling Formationin Southwestern China

The Luoping Biota discovered from the early Middle Triassic (Anisian) Guanling Formation of southwestern China represents a fully recovered shallow marine ecosystem, marking the end point of Early Triassic biotic recovery following the end-Permian mass extinction. Contemporaneously preserved are prolific trace fossils, which offer good opportunities to understand the palaeoecology of marine invertebrates from a fully recovered shallow marine ecosystem. Here we present a newly discovered sinuous branching burrow from the fossil-bearing unit in Member Ⅱ of the Guanling Formation. Several features, including the horizontal regular sinuous nature, the branching pattern, typical H-junction, and the small wavelength/amplitude ratio of these sinuous structures within the burrow systems justify assignment of these traces as Sinusichnus sinuosus, a trace possibly produced by decapod crustaceans. Close association of S. sinuosus with Rhizocorallium commune suggests a deposit-feeding strategy of these trace makers. The newly reported Anisian material from the Guan-ling Formation in Luoping represents first report of Sinusichnus from South China. The global record of Sinusichnus occurrence suggests that these burrows might have an older history than Early Middle Triassic.

Badger setts provide thermal refugia, buffering changeable surface weather conditions

Den use can be crucial in buffering environmental conditions and especially to provide an insulated environment for raising altricial young. Through Sept-Dec 2016 we monitored temperature and humidity at 11 badger setts (burrow systems), using thermal probes inserted over 4–13 sett entrances to a depth of ca. 2 m, supplemented by continuous daily logging at one entrance per sett. Setts were cooler than exterior conditions Sept-Oct, and warmer than exterior conditions Nov-Dec. Setts cooled down when badgers left them to forage by night, and warmed up when badgers occupied them by day. Soil type and aspect also influenced sett temperature. Sett temperature did not affect the weight or body-condition of either adults or maturing cubs in autumn. However, cubs born into setts that were relatively warmer through the preceding autumn-winter were heavier in the following spring than contemporaries born in cooler setts (badgers exhibit delayed implantation), and so warmer setts might benefit early cub growth. We posit that sett quality may be important in providing badgers with a stable thermal refuge from variable weather conditions. More broadly, den use may buffer climate change effects for many fossorial carnivore species.

Under the weather?—The direct effects of climate warming on a threatened desert lizard are mediated by their activity phase and burrow system

For ectotherms such as lizards, the importance of behavioural thermoregulation in avoiding thermal extremes is well-established and is increasingly acknowledged in modern studies of climate warming and its impacts. Less appreciated and understood are the buffering roles of retreat sites and activity phase, in part because of logistical challenges of studying below-ground activity. Burrowing and nocturnal activity are key behavioural adaptations that have enabled a diverse range of reptiles to survive extreme environmental temperatures within hot desert regions. Yet, the direct impact of recent global warming on activity potential has been hypothesised to have caused extinctions in desert lizards, including the Australian arid zone skink Liopholis kintorei. We test the relevance of this hypothesis through a detailed characterisation of the above- and below-ground thermal and hydric microclimates available to, and used by, L.kintorei. We integrate operative temperatures with observed body temperatures to construct daily activity budgets, including the inference of subterranean behaviour. We then assess the likelihood that contemporary and future local extinctions in this species, and those of similar burrowing habits, could be explained by the direct effects of warming on its activity budget and exposure to thermal extremes. We found that L.kintorei spent only 4% of its time active on the surface, primarily at dusk, and that overall potential surface activity will be increased, not restricted, with climate warming. The burrow system provides an exceptional buffer to current and future maximum extremes of temperature (≈40°C reduction from potential surface temperatures), and desiccation (burrows near 100% humidity). Therefore, any climate warming impacts on this species are likely to be indirect. Our findings reflect the general buffering capacity of underground microclimates, therefore, our conclusions for L.kintorei are more generally applicable to nocturnal and crepuscular ectotherms, and highlight the need to consider the buffering properties of retreat sites and activity phase when forecasting climate change impacts.

Unraveling the cryptic life of the southern naked-tailed armadillo, Cabassous unicinctus squamicaudis (Lund, 1845), in a Neotropical wetland: Home range, activity pattern, burrow use and reproductive behaviour

The natural history of the southern naked-tailed armadillo Cabassous unicinctus squamicaudis is not well known. Here, we provide basic information about burrow systems, home ranges, activity, morphometric measures, and reproductive behaviour. We monitored 10 individuals through VHF telemetry and direct observations in the central Pantanal of Brazil for 24 months. Males (2.06 km2) had significantly larger home ranges than females (0.59 km2) and home ranges of males overlapped with those of several females. There was very little overlap in ranges of the same sex and very few social interactions were observed. Southern naked-tailed armadillos dug convoluted galleries to forage, and, unless they used their entrance to exit, they emerged on average 2 m away (ranging from 0.01 m to 17 m) from the burrow entrance. When leaving their burrows, they spend on average 6.5 min above ground, travelling an average of 83 m (ranging from 1 m to 781 m) before going back underground. They do not return to sleep in a particular burrow, changing burrows frequently. The studied armadillos were diurnal, and spend 99.25% of the day underground, emerging only during the hottest period of the day (mid-afternoon). The southern naked-tailed armadillos should be classified as a subterranean species, rather than fossorial since they spent most of their time underground where foraging also takes place. Minimum densities of C. u. squamicaudis were estimated at 2.21 adults/km2. Gestation was estimated to last for 4 months. Parental care of a single young lasted on average 4 months. Niche overlap between E. sexcinctus and C. u. squamicaudis in the study area is minimal.

Coniacian sandstones from the North Sudetic Synclinorium revisited: palaeoenvironmental and palaeogeographical reconstructions based on trace fossil analysis and associated body fossils

AbstractThe Coniacian quartz sandstones (Żerkowice Member, Rakowice Wielkie Formation) that crop out at quarries near Czaple-Nowa Wieś Grodziska (North Sudetic Synclinorium) contain a low-diversity assemblage of trace fossils:Gyrochorteisp.,Ophiomorpha nodosaLundgren, 1891,Ophiomorphaisp.,Phycodescf.curvipalmatum(Pollard, 1981), ?Phycodesisp.,Planolitescf.beverleyensis(Billings, 1862),Thalassinoides paradoxicusWoodward, 1830 and ?Thalassinoidesisp. Moreover, interesting compound burrow systems, here referred to asThalassinoides-Phycodescf.palmatusand ?Thalassinoides-Phycodes, were recognised at the Czaple Quarry. Additionally, ?Gyrochorteisp.,Phycodescf.flabellum(Miller and Dyer, 1878) and ?Treptichnusisp. were encountered at correlative levels in the Rakowice Małe Quarry. Some of these ichnotaxa have not been recorded previously from Coniacian sandstones of the Żerkowice Member. Additionally, in slabs of these sandstones, the gastropodNerinea bicinctaBronn, 1836 and the bivalveLima haidingeriZittel, 1866 were found. These interesting finds, in particular the gastropods, were already noted from the study area in the first half of the twentieth century by Scupin (1912–1913). Ethologically, the trace fossil assemblage is represented by domichnia or domichnia/fodinichnia (Ophiomorpha,Thalassinoides), fodinichnia (Phycodes) and pascichnia (Gyrochorte,Planolites). The compound burrow systems (Thalassinoides-Phycodes) are interpreted as dwelling/feeding structures. The possible tracemakers are crustaceans (Ophiomorpha,Thalassinoides) or worm-like animals (annelids and other) (Planolites, ?Phycodes,Gyrochorteand ?Treptichnus). The assemblage of trace fossils is characteristic of theSkolithosichnofacies andCruzianaichnofacies, typical of shallow-marine settings. Ichnological studies, as well as the presence of accompanying fossils (bivalves, gastropods), confirm the palaeoenvironmental reconstruction of the Żerkowice Member sandstones by Leszczyński (2010). That author interpreted the Coniacian sandstones as bar and storm deposits laid down in a shallow epicontinental sea (mainly the foreshore-upper shoreface; up to the middle shoreface) under normal oxygenation and salinity, in soft substrate, above fair-weather wave base. The deposition of the Żerkowice Member sandstones is linked to a regression that started after uplift of the southeastern part of the North Sudetic Synclinorium.

P.2.035 - Studying social withdrawal in group housed mice using semi-natural conditions

Background Currently, neuropsychiatric disorders are separated by convention based clustering of qualitative symptoms, not underlying aetiology. This methodology might be sufficient for general clinical management, but it disregards neurobiology. A better understanding of the neurobiology and the application of this knowledge will lead to enhanced treatment efficacy and would provide patients with improved understanding of their condition. A first step in linking nosology to neuroscience is showing how neuropsychiatric symptoms can be measured by quantitative biological parameters and, how these quantitative biological parameters are shaped by neurobiological processes. For example, Schizophrenia, Alzheimer’s disease, Major Depressive disorder and autism spectrum disorder have one overlapping symptom, social withdrawal [1]. This suggests that neurobiological mechanisms might overlap. Thus, scrutinizing the characteristics of this behavioural deficit could elucidate mechanisms relevant for multiple neuropsychiatric disorders. Animal studies are essential in this endeavour, as behaviour and the underlying mechanisms can be examined in more detail. However, efforts are needed to establish the definition and assessment tools for social withdrawal that is relevant beyond the diagnostic boundaries. In earlier studies, the focus has primarily been on scrutinizing social withdrawal in a dyadic interaction, in which a single animals can engage in social behaviour with a single other (e.g., [2]). This, however, does not allow for the natural behavioural potential, such as the natural burrowing behaviour of these animals. Studying social behaviour in a semi-natural environment would allow for a translational setting in which the full range of behaviours can be explored. This study proposes the visible burrow system (VBS) for this purpose. This system consists of an open arena and a burrow with separate nests, from which the latter is exposed to constant darkness. Mimicking the natural setting, this system allows rodents to display natural behaviours and withdraw into one of the nests. Aim This study aims to explore the full behavioural range of the BTBR mouse, a mouse line showing aberrant social behaviours, in a semi-natural VBS environment to study social withdrawal. Furthermore we aim to connect this to GABA, which has been shown to play a key role in social behaviour [3]. Method In assessing the full range of behavioural deficits accompanying social withdrawal, BTBR and C57BL/6J reference mice are placed in the VBS. Colonies of 8 mice (6 males and 2 females) are exposed to the VBS for five consecutive days after which animals are sacrificed and brains are extracted for GABA measurement by mean of HPLC. Statistical analyses is performed by means of ANOVA (longitudinal) and Student’s T-test (week means), comparing BTBR with C57Bl/6j mice (α=0.05). Results/Conclusion In accordance with previous data [4], BTBR mice showed a significant decrease in social behaviours and an increase in non-social behaviour. This coincided with a reduction of GABA in both the prefrontal cortex and the amygdala. Taken together, these data suggests the VBS as a tool for studying translation behavioural characteristics regarding social withdrawal and its neurochemical correlates.