Oliver Hampe

Revision of the Xenacanthida (Chondrichthyes: Elasmobranchii) from the Carboniferous of the British Isles

Xenacanthids were a very successful group of elasmobranchs that ranged from the Lower Carboniferous to the Upper Triassic. The history of discovery of the xenacanthids, which is closely connected with the history of coal prospecting in England, began with the finding of the type specimen of Xenacanthus laevissimus in the Westphalian B of the West Midlands. In this first review of British Carboniferous xenacanthids, the number of taxa, mainly erected during Victorian times, is reduced to 14 species distributed among six genera. Determinable remains are recorded from at least 96 localities in the British Isles. Unique characteristics of the Dinantian Diplodoselache suggest that the lineage to which this taxon belongs marks a dead end in xenacanthid evolution. This investigation also shows that the Pendleian Dicentrodus , formerly described as Cladodus , belongs to the xenacanthids. The occurrence of Orthacanthus cf. kounoviensis in the Pennines, also known from the German Saar-Nahe basin, the Saale depression and from Bohemia, indicates a faunal exchange between these intramontainous basins during the Carboniferous. The genus Triodus is identified from British deposits for the first time. A cladistic analysis of the xenacanthids suggests that they evolved from phoebodontid elasmobranchs. This analysis also confirms separation of the Middle Devonian Antarctilamna from a relationship with xenacanthid sharks.

Vertebral Pathology in an Ornithopod Dinosaur: A Hemivertebra in Dysalotosaurus lettowvorbecki from the Jurassic of Tanzania

A vertebral fragment of the Late Jurassic ornithopod dinosaur Dysalotosaurus lettowvorbecki from Tanzania is described. It consists of a hemivertebra that is co‐ossified with a complete vertebral centrum. The hemivertebra causes a hyperkyphotic posture of the vertebral column with an angle of approximately 35° between the end plates of the vertebra, that is, a dorsal bending of the vertebral column. Associated with this is a 15° lateral bending, which suggests a scoliosis. Micro‐CT scans reveal thickening of the cortical bone in the hemivertebra and the complete vertebral centrum as compared to a “normal” vertebra. This can be interpreted as a reaction of the bone to the abnormal direction of forces arising from the defective configuration of the vertebral column. No signs of vertebral fracture are present. The arrangement of the Foramina venosa and the trapezoidal outline of the complete centrum that is co‐ossified with the hemivertebra indicate that the hemivertebra in Dysalotosaurus developed early in embryogenesis probably by “hemimetameric segmental shift”, that is, a defect of the fusion of the paired vertebral anlagen. This finding illustrates that hemivertebrae represent a fundamental defect of the vertebrate ontogenetic program. Anat Rec, 291:1149‐1155, 2008.

Paget disease of bone in a Jurassic dinosaur

Summary Paget disease of bone — initially described by Sir James Paget in 1876 — is a benign bone disorder well known in human pathology. It leads to the enlargement and deformity of bones due to a combination of abnormal bone resorption and abundant new bone formation [1–3]. There is strong evidence that viruses are involved in the disease, coupled with a probable genetic component [3,4]. Paget disease in humans most frequently involves the skull, the spine and parts of the pelvis [1–3]. There is only limited evidence on Paget disease in other extant mammals, such as orangutans and lemurs [5]. Paget disease has also been described in human bones dating back to the Neolithic [6]. Here, we report Paget disease in a vertebra of the Jurassic dinosaur Dysalotosaurus lettowvorbecki , representing the oldest indirect evidence of viruses in the fossil record.

Dicentrodus (Chondrichthyes: Xenacanthida) from the Early Carboniferous (Visean: upper St Louis Formation) of Iowa, USA

Dicentrodus possessed bicuspid teeth with a flat base and nonserrated or finely serrated, labio-lingually compressed, highly unequal cusps. Originally known from the late Visean–early Serpukhovian of Scotland ( D. bicuspidatus ), it is now known also to occur in the middle Visean of North America. This is the earliest occurrence of a xenacanthid yet reported from North America; its presence is based on incomplete teeth, which are easily distinguished from other xenacanthid genera. The cross-continental distribution of Dicentrodus , like that of other xenacanthid genera, can be explained by an increasing body of data that intimate that xenacanthids were euryhaline sharks and not restricted to a freshwater habitat.

A benign bone-forming tumour (osteoma) on the skull of a fossil balaenopterid whale from the Pliocene of Chile

Hampe, O., Witzmann, F. & Asbach, P., 2014. A benign bone-forming tumour (osteoma) on the skull of a fossil balaenopterid whale from the Pliocene of Chile. Alcheringa 38, xxx–xxx. ISSN 0311–5518. A pathology of the fossil baleen whale ‘Megaptera’ hubachi from the early Pliocene of Chile is described. It is a bony outgrowth on the left side of the supraoccipital, which is interpreted as a benign bone-forming tumour (osteoma). This diagnosis is based on X-ray imaging and CT scans of the abnormal bone, revealing a homogeneously dense internal structure with no evidence for lytic areas. The osteoma described here in ‘Megaptera’ hubachi is the first unequivocal evidence of a bone tumour in a cetacean, fossil or extant. Oliver Hampe [oliver.hampe@mfn-berlin.de] and Florian Witzmann [florian.witzmann@mfn-berlin.de], Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, D-10115 Berlin, Germany; Patrick Asbach [patrick.asbach@charite.de], Institut für Radiologie, Charité—Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany. Received 28.8.2013, revised 7.11.2013, accepted 12.11.2013.

Röntgen- und Neutronentomographie am knöchernen Innenohr der Bartenwale

Kurzfassung Für die Orientierung in den Tiefen der Ozeane entwickelten Wale und Delphine im Laufe der Evolution ein spezialisiertes Hörorgan für ein breites akustisches Spektrum. Die innere Anatomie des Felsenbeins (Perioticum), insbesondere die Morphologie der Hörschnecke (Cochlea) hat bei Säugetieren einen signifikanten Einfluss auf das Hörvermögen. Mittels Röntgen- und Neutronentomographie wird die knöcherne oder fossilisierte Cochlea verschiedener fossiler Repräsentanten ausgestorbener Bartenwalgruppen (wie der Cetotheriidae) sowie moderner Furchenwale (Balaenopteridae) und Glattwale untersucht, ebenso die eines Urwals und einiger Landwirbeltiere. Morphologische Veränderungen, die für die Entwicklung des niederfrequenten Hörens verantwortlich sein können, sollen so erfasst werden. Unterschiede in der Cochlea-Morphologie werden anhand morphometrischer Parameter, wie der Anzahl der Windungen, der Länge der Cochlea und des Krümmungsverlaufs des Cochleakanals bestimmt. Insbesondere die Röntgentomographie ermöglicht eine hochauflösende Darstellung des knöchernen Innenohrs.