Conellae, enigmatic structures on cephalopod shells—shapes, distribution, and formation

Conellae, enigmatic cone-shaped structures which can be found on the surface of internal moulds of cephalopod shells (predominantly of ammonoids), are regarded herein as the product of remote (biologically induced) biomineralization formed in closed-off cavities during lifetime and might be primarily composed of vaterite, aragonite, or calcite. To date conellae have been interpreted in many different ways: (i) as organisms (gastropods, cirriped crustaceans, or disciniscid brachiopods), (ii) pre-diagenetic syn vivo features, i.e., biologically controlled or induced, the product of remote biomineralization, (iii) and diagenetic, i.e., abiogenic origin and post-mortem. The proposed processes of conellae formation seem insufficient to explain conellae related phenomena. Further, their assumed primary aragonitic or calcitic mineralogy are reviewed and based on new material critically assessed. The stratigraphic range of conellae extends from the Middle Ordovician and probably to modern Nautilus. Predominantly, conellae can be found on internal moulds along the keel, ribs or nodes, umbilical shoulder, at the transition between phragmocone and body chamber, and can be associated with repaired scars. However, conellae are also common on the smooth body chambers of large macroconchs of Jurassic ammonites. Conellae, which are located on ammonite body chambers, are filled with the same material found in the body chamber and can contain small burrows, sand grains, or coprolites. Some of these conellae are partially covered with nacreous shell material. Limonitic conellae were also found on the limonitic internal moulds of orthocone nautiloids. Moreover, disciniscid brachiopods found on inoceramid bivalves were re-identified herein as conellae. A short guide for conellae identification has been provided herein

Evolutionary development of the cephalopod arm armature: a review

The cephalopod arm armature is certainly one of the most important morphological innovations responsible for the evolutionary success of the Cephalopoda. New palaeontological discoveries in the recent past afford to review and reassess origin and homology of suckers, sucker rings, hooks, and cirri. Since a priori character state reconstructions are still ambiguous, we suggest and discuss three different evolutionary scenarios. Each of them is based on the following assumptions: (1) Neocoleoidea uniting extant Decabrachia and Octobrachia is monophyletic (= proostracum-bearing coleoids); (2) extinct Belemnitida and Diplobelida are stem decabrachians; (3) proostracum-less coleoids (Hematitida, Donovaniconida, Aulacoceratida) represent stem-neocoleoids; (4) Ammonoidea and Bactritoidea are stem coleoids. We consider a scenario where belemnoid hooks derived from primitive suckers as well-supported. Regarding belemnoid hooks and suckers as homologues implies that belemnoid, oegopsid, and probably ammonoid arm hooks arose through parallel evolution. Our conclusions challenge the widespread opinion, whereupon belemnoid hooks evolved de novo, and instead support earlier ideas formulated by Sigurd von Boletzky

The correct taxon name, authorship, and publication date of extant ten-armed coleoids

A variety of conflicting names with different authorship is available and has been repeatedly cited for living ten-armed coleoid cephalopods. Here, I review the primary literature and show the correct name, authorship, and date for ten-armed coleoids

Geometric morphometrics in ammonoids based on virtual modelling

Linear morphometrics is the most widely applied technique to study the variationof the conch morphology in ammonoids and other ectocochleate cephalopods. However,because this method frequently relies upon a few linear measurements, it lacksthe explanatory power to accurately characterize the shape of the whorl cross-section,which is instead discussed solely in descriptive terms, e.g., elliptical, triangular, or subquadrate.Here, we introduce a landmark-based geometric morphometric approach tostudy ammonoid whorl cross-sections, derived from the regularly used morphometricparameters in cephalopods. This new technique uses virtual modelling to generatesemi-landmark configurations and virtual models of whorl cross-sections. We applied itto study 50 ammonoid specimens belonging to 48 genera exhibiting a wide range ofmorphologies and ages. Results indicate that this new method is appropriate todescribe the shape of ammonoid whorl cross-sections, allowing us to construct a morphospaceshowing several biological patterns (e.g., clustering and homeomorphy), andcomplex morphological transformations that, in some cases, correlate with evolutionarytendencies described by previous authors. Further, this technique can be used togenerate the basic segment required for the elaboration of the virtual models employedin hydrostatic and hydrodynamic studies.Fil: Moron Alfonso, Daniel Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Hoffmann, René. Ruhr Universität Bochum; AlemaniaFil: Cichowolski, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Special issue: recent advances in Cambrian to modern cephalopod research I

In September 2014, the 9th International Symposium Cephalopods—Present and Past was held at the Universitz of Zurich in combination with the 5th International Coleoid Symposium. Here, give a short account of these two events

Takahashiceras – A new generic name proposed for Takahashia Matsumoto, 1984

We propose Takahashiceras as a replacement name for the pre-occupied Upper Cretaceous ammonite genus Takahashia Matsumoto 1984

Preservation of nautilid soft parts inside and outside the conch interpreted as central nervous system, eyes, and renal concrements from the Lebanese Cenomanian

Nautilid, coleoid and ammonite cephalopods preserving jaws and soft tissue remains are moderately common in the extremely fossiliferous Konservat-Lagerstätte of the Hadjoula, Haqel and Sahel Aalma region, Lebanon. We assume that hundreds of cephalopod fossils from this region with soft-tissues lie in collections worldwide. Here, we describe two specimens of Syrionautilus libanoticus (Cymatoceratidae, Nautilida, Cephalopoda) from the Cenomanian of Hadjoula. Both specimens preserve soft parts, but only one shows an imprint of the conch. The specimen without conch displays a lot of anatomical detail. We homologise the fossilised structures as remains of the digestive tract, the central nervous system, the eyes, and the mantle. Small phosphatic structures in the middle of the body chamber of the specimen with conch are tentatively interpreted as renal concrements (uroliths). The absence of any trace of arms and the hood of the specimen lacking its conch is tentatively interpreted as an indication that this is another leftover fall (pabulite), where a predator lost parts of its prey. Other interpretations such as incomplete scavenging are also conceivable

Dichotomous Impact of Myc on rRNA Gene Activation and Silencing in B Cell Lymphomagenesis

A major transcriptional output of cells is ribosomal RNA (rRNA), synthesized by RNA polymerase I (Pol I) from multicopy rRNA genes (rDNA). Constitutive silencing of an rDNA fraction by promoter CpG methylation contributes to the stabilization of these otherwise highly active loci. In cancers driven by the oncoprotein Myc, excessive Myc directly stimulates rDNA transcription. However, it is not clear when during carcinogenesis this mechanism emerges, and how Myc-driven rDNA activation affects epigenetic silencing. Here, we have used the Eµ-Myc mouse model to investigate rDNA transcription and epigenetic regulation in Myc-driven B cell lymphomagenesis. We have developed a refined cytometric strategy to isolate B cells from the tumor initiation, promotion, and progression phases, and found a substantial increase of both Myc and rRNA gene expression only in established lymphoma. Surprisingly, promoter CpG methylation and the machinery for rDNA silencing were also strongly up-regulated in the tumor progression state. The data indicate a dichotomous role of oncogenic Myc in rDNA regulation, boosting transcription as well as reinforcing repression of silent repeats, which may provide a novel angle on perturbing Myc function in cancer cells

Prävalenz von Demenz bei Menschen mit Migrationshintergrund in Deutschland

Hintergrund: In Deutschland lebten 2013 16,5 Mio. Menschen mit Migrationshintergrund, wovon schätzungsweise 9 % älter als 65 Jahre sind. Sie zeigen häufig schlechtere Gesundheitsoutcomes als Menschen ohne Migrationshintergrund, aber aus verschiedenen Gründen werden Gesundheits- und Pflegeleistungen kaum genutzt. Für diese Population gibt es keine systematischen Angaben zur Anzahl Demenzerkrankter. Dies hat zur Folge, dass das Gesundheitssystem vor einer Herausforderung steht, dessen Dimension kaum einzuschätzen ist. Ziel: Darstellung der Prävalenz von Demenz bei Menschen mit Migrationshintergrund für Deutschland und die einzelnen Bundesländer. Methode: Länderspezifische Daten zu Bevölkerung, Demenzerkrankten und altersspezifischen Prävalenzen wurden genutzt, um länderspezifische Prävalenzen für verschiedene Ethnien zu berechnen. Daraus wurde die Anzahl von Menschen mit Migrationshintergrund und Demenz in Deutschland geschätzt, und wie diese sich auf die Bundesländer verteilen. Ergebnisse: Von 1,86 Mio. Menschen mit Migrationshintergrund in Deutschland, die 65 Jahre oder älter sind, sind schätzungsweise 96.500 Personen (5,2 %) an Demenz erkrankt. Der Großteil entfällt auf Menschen mit polnischem (13.960), italienischem (8920) und türkischem (8840) bzw. europäischem Hintergrund (84.490). Die vermutlich höchsten Erkrankungszahlen zeigen Nordrhein-Westfalen (26.000), Baden-Württemberg (18.080) und Bayern (16.710). Diskussion: Unsere Analysen zeigen die Anzahl an Demenz erkrankter Menschen mit Migrationshintergrund separat für ausgewählte Herkunftsländer als auch die deutschen Bundesländer. Dies bildet eine erste Grundlage für eine länderspezifische Handlungssteuerung und die Planung kultursensibler Angebote zur Versorgungsverbesserung der an Demenz erkrankten Menschen mit Migrationshintergrund.Background: In Germany the number of people with a migration background was 16.5 million people in 2013 with 9% being older than 65 years. In this population utilization of health services is low, especially in older people, although they often display worse health outcomes. Little is known about the number of people with dementia and migration background in Germany and their distribution on the state level, resulting in a challenge that is barely assessable for the healthcare system. Objective: The depiction of the prevalence of dementia in people with a migration background for Germany and the individual federal states. Method: The number of people with a migration background and dementia living in Germany and the individual federal states was estimated for different ethnic groups using country and state-specific data on the population, dementia frequency and age-specific prevalence. Results: Out of 1.86 million people with a migration background who are 65 years or older, approximately 96,500 persons (5.2%) have dementia. The majority are of European (84,490), more specifically Polish (13,960), Italian (8920) and Turkish (8840) heritage. North Rhine-Westphalia (26,000), Baden-Wuerttemberg (18,080) and Bavaria (16,710) are presumed to show the highest rates of people affected. Conclusion: In Germany people with a migration background and dementia represent a large target group for health care; however, the numbers and ethnic populations affected differ considerably between states. These analyses can be used for state-specific healthcare planning of culture-specific and culture-sensitive services and care so that specific healthcare improvements can be achieved

‘Arm brains’ (axial nerves) of Jurassic coleoids and the evolution of coleoid neuroanatomy

Although patchy, the fossil record of coleoids bears a wealth of information on their soft part anatomy. Here, we describe remains of the axial nerve cord from both decabrachian (Acanthoteuthis, Belemnotheutis, Chondroteuthis) and octobrachian (Plesioteuthis, Proteroctopus, Vampyronassa) coleoids from the Jurassic. We discuss some hypotheses reflecting on possible evolutionary drivers behind the neuroanatomical differentiation of the coleoid arm crown. We also propose some hypotheses on potential links between habitat depth, mode of life and the evolution of the Coleoidea