Christian Neumann

A Foraminiferal Parasite on the Sea Urchin Echinocorys: Ichnological Evidence from the Late Cretaceous (Lower Maastrichtian, Northern Germany)

In contrast to most other marine invertebrates, echinoderms favor the recognition of a syn vivo infestment of parasites and commensals by the specific response of their skeletal tissues. Attachment or embedment structures, but also repair features commonly mirror the anatomical morphology of the trace maker and may therefore be of interpretive value. Among the numerous groups of invertebrates associated with sea urchins, only a few are tightly attached to the external surface of the host, leaving visible damage on the skeleton. Here, we describe etched attachment scars, a few millimeters in size, produced by a circular to subcircular organism on the oral surface of the holasteroid echinoid Echinocorys perconica (von Hagenow, 1840) from the Lower Maastrichtian chalk of northern Germany. We compare the traces with Recent attachment scars produced by benthic foraminifers such as Hyrrokkin sarcophaga and consequently suggest a parasitic foraminifer as the most probable trace maker.

Fossil Mayfly Collections of the Museum Für Naturkunde, Humboldt University, Berlin. II. Redescription of Baltameletus oligocaenicus Demoulin, 1968 with Notes on Ameletidae McCafferty, 1991 (Insecta: Ephemeroptera) from the Eocene Baltic Amber

Abstract. The holotype of Baltameletus oligocaenicus Demoulin, 1968 preserved in Eocene Baltic amber and housed in the W. Simon amber collection at the Museum für Naturkunde, Humboldt University, Berlin is redescribed and illustrated. Baltameletus Demoulin, 1968 can be attributed to the family Ameletidae McCafferty, 1991 by a combination of following characteristics: (1) lateroparapsidal suture of mesothorax relatively elongate; (2) epimeron of mesothorax with membranous area between anepimeron and katepimeron; (3) mesonotal suture stretched backward medially and anterior paracoxal suture complete; (4) furcasternal protuberances contiguous; (5) hind wings well developed with RS, MA and MP triads; (6) tarsi 5-segmented with first tarsal segment fused with tibia; (7) forceps with two distal segments; (8) all tarsal claws dissimilar. This fossil genus clearly differs from all other representatives of the family Ameletidae by the following combination of characteristics: (1) unpaired projection of the vertex; (2) dorsally contiguous compound eyes (3); 2–3 mainly simple veins stretching from CuA to basitornal margin of forewing. Additionally, some data on the fossil representatives of Ameletidae are given.

Coulonia parva n. sp., a new species of Astropectinidae (Asteroidea; Echinodermata) from the Santonian (Upper Cretaceous) of Sierra de Montsech (southern Pyrenees, Spain)

A new astropectinid sea star,Coulonia parva n. sp., is described from the Santonian of the Sierra de Montsech, northern Spain. The single specimen shows part of a rather weathered ventral side. It is characterized by comparatively long arms (R/r approx. 3/1), with one row of actinals reaching far into the arms; inferomarginals on the interbrachial arc have deep fasciolar grooves that are less developed on the arms; there are no larger spines on adambulacrals and probably also on inferomarginals. Based on presence of deep marginal fascioles,C. parva n. sp. is inferred to have shared the capability for self-burial with the relatedC. platyspinaHess &Blake.KurzfassungCoulonia parva n. sp., ein neuer Seestern aus der Familie der Astropectinidae, wird aus dem Santon der Sierra de Montsech (Spanien) beschrieben. Es liegt nur ein einziges Exemplar vor, welches einen Teil der Ventralseite zeigt.Coulonia parva n. sp. ist durch vergleichsweise lange Arme (R/r ungefähr 3/1) gekennzeichnet. Darüber hinaus reicht jeweils eine Reihe von Actinalia weit in die Arme hinein; die Inferomarginalia des Interbrachialbogens besitzen tiefe Fasziolargruben, die auf den Inframarginalia der Arme weniger stark entwickelt sind. Vermutlich trugen weder die Adambulakralia noch die Inframarginalia längere Stacheln. Basierend auf dem Vorhandensein der tiefen Fasziolargruben auf den Marginalia wird fürC. parva die Fähigkeit angenommen, sich einzugraben, wie sie bereits für die verwandte ArtC. platyspinaHess &Blake aus dem Barrème von Marokko postuliert wurde.

Fecal Microbiota Transplantation, Commensal Escherichia coli and Lactobacillus johnsonii Strains Differentially Restore Intestinal and Systemic Adaptive Immune Cell Populations Following Broad-spectrum Antibiotic Treatment

The essential role of the intestinal microbiota in the well-functioning of host immunity necessitates the investigation of species-specific impacts on this interplay. Aim of this study was to examine the ability of defined Gram-positive and Gram-negative intestinal commensal bacterial species, namely Escherichia coli and Lactobacillus johnsonii, respectively, to restore immune functions in mice that were immunosuppressed by antibiotics-induced microbiota depletion. Conventional mice were subjected to broad-spectrum antibiotic treatment for 8 weeks and perorally reassociated with E. coli, L. johnsonii or with a complex murine microbiota by fecal microbiota transplantation (FMT). Analyses at days (d) 7 and 28 revealed that immune cell populations in the small and large intestines, mesenteric lymph nodes and spleens of mice were decreased after antibiotic treatment but were completely or at least partially restored upon FMT or by recolonization with the respective bacterial species. Remarkably, L. johnsonii recolonization resulted in the highest CD4+ and CD8+ cell numbers in the small intestine and spleen, whereas neither of the commensal species could stably restore those cell populations in the colon until d28. Meanwhile less efficient than FMT, both species increased the frequencies of regulatory T cells and activated dendritic cells and completely restored intestinal memory/effector T cell populations at d28. Furthermore, recolonization with either single species maintained pro- and anti-inflammatory immune functions in parallel. However, FMT could most effectively recover the decreased frequencies of cytokine producing CD4+ lymphocytes in mucosal and systemic compartments. E. coli recolonization increased the production of cytokines such as TNF, IFN-γ, IL-17, and IL-22, particularly in the small intestine. Conversely, only L. johnsonii recolonization maintained colonic IL-10 production. In summary, FMT appears to be most efficient in the restoration of antibiotics-induced collateral damages to the immune system. However, defined intestinal commensals such as E. coli and L. johnsonii have the potential to restore individual functions of intestinal and systemic immunity. In conclusion, our data provide novel insights into the distinct role of individual commensal bacteria in maintaining immune functions during/following dysbiosis induced by antibiotic therapy thereby shaping host immunity and might thus open novel therapeutical avenues in conditions of perturbed microbiota composition.