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WvK, CW, and UBG conceived and designed the study, performed the investigation, analyzed the data, prepared figures and tables, authored or reviewed drafts of the paper, approved the final draft.
The enamel microstructure of molars in Mexican soricines Megasorex and Cryptotis is described and compared to the six types of schmelzmuster found in fossil and recent Soricidae. These types of schmelzmuster show a high correlation to the... more
The enamel microstructure of molars in Mexican soricines Megasorex and Cryptotis is described and compared to the six types of schmelzmuster found in fossil and recent Soricidae. These types of schmelzmuster show a high correlation to the current systematics of Soricidae. In Megasorex, the relatively simple schmelzmuster is dominated by radial enamel. However, a very thin innermost layer of differentiated enamel indicates the beginning of a two-layered schmelzmuster. This corresponds to the Notiosorex-schmelzmuster. The teeth of Megasorex lack pigmentation, which is not reflected in its schmelzmuster. Similarities to the white-toothed Crocidura-schmelzmuster are superficial. Cryptotis has the typical two-layered enamel of derived Soricinae. The specific enamel type of the inner layer and the strong lateral inclination of its prisms represent a new modification of the highly derived Blarina-schmelzmuster. Zusammenfassung: Die Mikrostruktur des Zahnschmelzes in den Molaren der Mexikanischen Spitzmäuse, Megasorex und Cryptotis, wird beschrieben und mit den sechs Schmelzmuster-Typen verglichen, die von den fossilen und rezenten Soriciden bekannt sind. Die unterschiedenen Schmelzmuster-Typen weisen eine sehr hohe Übereinstimmung mit der derzeitigen systematischen Gliederung der Soriciden auf. Das Schmelzmuster von Megasorex ist relativ einfach und wird von radialem Schmelz dominiert. Aber eine sehr dünne Innenschicht weist auf eine beginnende Zweischichtigkeit hin, wie sie im Notiosorex-Schmelzmuster zu beobachten ist. Den Zähnen von Megasorex fehlt die Pigmentierung, die sich aber nicht auf das Schmelzmuster auswirkt. Eine gewisse Ähnlichkeit zum dem Schmelzmuster der weißzähnigen Crocidura ist nur oberflächlich. Cryptotis hat das für evoluierte Soricinae typische zwei-schichtige Schmelzmuster. Der besondere Schmelztyp der Innenschicht und die starke seitliche Neigung der Prismen belegen eine Zugehörigkeit zum hoch abgeleiteten Blarina-Schmelzmuster, wobei Cryptotis eine neue Modifikation belegt.
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Text-fig. 5. Cryptotis magna, details of the schmelzmuster. a) Detail from the pald more closely to the prd. The REIS of the inner layer is strongly inclined to the right (prd). Because the prisms are almost horizontal, the IPM occurs as a sheet between the rows of prisms. The crystallites of the...more
Text-fig. 5. Cryptotis magna, details of the schmelzmuster. a) Detail from the pald more closely to the prd. The REIS of the inner layer is strongly inclined to the right (prd). Because the prisms are almost horizontal, the IPM occurs as... more
Text-fig. 5. Cryptotis magna, details of the schmelzmuster. a) Detail from the pald more closely to the prd. The REIS of the inner layer is strongly inclined to the right (prd). Because the prisms are almost horizontal, the IPM occurs as a sheet between the rows of prisms. The crystallites of the IPM are perpendicular to the direction of prisms. b) In the protoconid, the two-layered enamel is obvious. In the inner layer, prisms are inclined from both sides, from the pald and prod. The IPM is almost perpendicular to the prisms. The outer layer is of radial enamel. c) The paraconid shows slightly inclined prisms and IPM, and most is radial enamel. d) Detail from the pald. The inner layer is formed by radial enamel with inter-row sheets (REIS). In the left part of the picture, a minimal inclination towards the left (pad) is recognizable. The outer layer is composed of radial enamel. Note the step close to the margin between the two enamel types. It is caused by pigmentation in the oute...
Cricetid rodents have a very high reproductive capacity and usually a short life span, measured in months rather than years. Many of them are also non-gregarious, searching for new resources outside the confines of their present habitat.... more
Cricetid rodents have a very high reproductive capacity and usually a short life span, measured in months rather than years. Many of them are also non-gregarious, searching for new resources outside the confines of their present habitat. These features provide cricetid rodents with valuable attributes as agents of historical biology. We describe a new species of cricetid rodent, Paciculus walshi, an Oligocene cricetid rodent in North America; we characterise its enamel microstructure and dental features and review its relationship with other cricetid rodents globally, to place it within the framework of Oligocene historical biology.
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Three functional aspects (jaw movement, collapse of lophs by wear, and molar wear gradient) are described for Lophiodon and compared with typical lophodont dentitions in other mammals, e.g., Macropus, Pyrotherium and Deinotherium. The jaw... more
Three functional aspects (jaw movement, collapse of lophs by wear, and molar wear gradient) are described for Lophiodon and compared with typical lophodont dentitions in other mammals, e.g., Macropus, Pyrotherium and Deinotherium. The jaw movement is deduced from striations and guiding rails. In Lophiodon only phase I of the power stroke is documented by facets, whereas a minor phase II occurs in Macropus. During phase I the lophs perform two functions: cutting when the crests are passing each other, and compressing the bolus during further interlocking. When dentine is exposed the lophs collapse and lose their trenchant function and are grinding only. The sudden collapse of the lophs is partially due to the abrasion within the compression chamber, as seen in Dendrolagus. The molar wear gradient (the differential wear between the first and last molars) is low in Pyrotherium, intermediate in Lophiodon, and Deinotherium as compared with a low molar wear gradient in Tapirus or a high g...
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Gondwanatherians are an enigmatic group of extinct non-therian mammals apparently restricted to some of the western Gondwanan continents (Late Cretaceous-early Palaeocene of South America, and Late Cretaceous of Madagascar and India).... more
Gondwanatherians are an enigmatic group of extinct non-therian mammals apparently restricted to some of the western Gondwanan continents (Late Cretaceous-early Palaeocene of South America, and Late Cretaceous of Madagascar and India). They developed rodent-like incisors and the earliest known hypsodont cheek-teeth among mammals. Recently, a small rodent-like dentary fragment was recovered from middle Eocene beds on the Antarctic Peninsula, preserving part of the incisor; both the incisor enamel structure and the mandibular morphology suggest close affinities with Sudamerica ameghinoi from the early Palaeocene of Patagonia, up to now the youngest known Gondwanatheria. Thus, the new specimen becomes the youngest occurrence of a gondwanathere, adding significant direct and indirect evidence on: (1) the already documented cosmopolitanism of gondwanatheres among Gondwanan mammals; and (2) the crucial biogeographical role of Antarctica during the Cretaceous-Tertiary mammalian transition.
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be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The... more
be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
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Text-fig. 5. Allosorex stenodus FEJFAR, 1966 – fragment of left P4 and left M3, Ivanovce, fissure 6523. a–d: P4 sin. (Z 28201 – OF 6523; a, c – lingual view, b, d – occlusal view, a–b – hypothetical reconstruction of the premolar), e–f: M3 sin. (Z 28202 – OF 6523; occlusal view). in Allosorex Ste...more
Text-fig. 5. Allosorex stenodus FEJFAR, 1966 – fragment of left P4 and left M3, Ivanovce, fissure 6523. a–d: P4 sin. (Z 28201 – OF 6523; a, c – lingual view, b, d – occlusal view, a–b – hypothetical reconstruction of the premolar), e–f:... more
Text-fig. 5. Allosorex stenodus FEJFAR, 1966 – fragment of left P4 and left M3, Ivanovce, fissure 6523. a–d: P4 sin. (Z 28201 – OF 6523; a, c – lingual view, b, d – occlusal view, a–b – hypothetical reconstruction of the premolar), e–f: M3 sin. (Z 28202 – OF 6523; occlusal view).
Text-fig. 3. Megasorex gigas, details of the schmelzmuster. a) Enamel of the protoconid in cross-section. Note the very thin inner layer of prisms that are partially separated by inter-row sheets (REIS). b) enamel of the paraconid showing only radial enamel. Abbreviations: pad – paraconid, pald –...more
Text-fig. 3. Megasorex gigas, details of the schmelzmuster. a) Enamel of the protoconid in cross-section. Note the very thin inner layer of prisms that are partially separated by inter-row sheets (REIS). b) enamel of the paraconid showing... more
Text-fig. 3. Megasorex gigas, details of the schmelzmuster. a) Enamel of the protoconid in cross-section. Note the very thin inner layer of prisms that are partially separated by inter-row sheets (REIS). b) enamel of the paraconid showing only radial enamel. Abbreviations: pad – paraconid, pald – paralophid, prd – protoconid.
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ABSTRACT
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Diversity of hypsodont teeth in mammalian dentitions – construction and classification by Wighart v. Koenigswald with 9 text-figures and 3 tables This paper is dedicated with great respect to Prof. em. Dr. Adolf Seilacher of Tü bingen and... more
Diversity of hypsodont teeth in mammalian dentitions – construction and classification by Wighart v. Koenigswald with 9 text-figures and 3 tables This paper is dedicated with great respect to Prof. em. Dr. Adolf Seilacher of Tü bingen and Ya le. Dolf successfully inspired many students with his understanding of 'Constructional Morphology.' He opened many eyes, mine included, to the trade-offs of history, function, and construction that constrain morphology. Zusammenfassung Hypsodontie, so wie der Begriff hier gebraucht wird, beschreibt Zähne, deren Krone parallel zur Wa chstumsrichtung verlängert ist. Diese Zahnform kann in allen Zahnpositionen auftreten. Die Hypodontie wird als die heterochrone Verlängerung bestimmter ontogenetischer Phasen während der Zahnbildung auf Kosten der anderen Phasen interpretiert. Mit drei Kriterien lässt sich die Viel-falt hypsodonter Zähne unterscheiden: zum einen geht es darum, welche Phase (oder Phasen) in der Ontogenie verlängert sind, zum a...
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Der Birkhauser Verlag hat mich gebeten, ein Nachwort fur die deutschsprachige Ausgabe des Buches „The Call ofDistant Mammoths“ von Peter D. Ward uber das Verschwinden der grosen eiszeitlichen Saugetiere zu schreiben. Ich selbst habe seit... more
Der Birkhauser Verlag hat mich gebeten, ein Nachwort fur die deutschsprachige Ausgabe des Buches „The Call ofDistant Mammoths“ von Peter D. Ward uber das Verschwinden der grosen eiszeitlichen Saugetiere zu schreiben. Ich selbst habe seit mehreren Jahrzehnten, haufig in Zusammenarbeit mit Archaologen, uber die Saugetiere des Eiszeitalters in Europa gearbeitet. Mit Interesse habe ich das grosartig dargestellte Feuerwerk der sich widerstreitenden Ideen und Hypothesen gelesen, in deren Mittelpunkt sich der Autor selbst darzustellen weis.
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ABSTRACT The occlusal morphology and continuous molar replacement in elephants provide a very effective functional area for grinding the biomass that is more or less abrasive. Parts of two subsequent molars contribute to the “functional... more
ABSTRACT The occlusal morphology and continuous molar replacement in elephants provide a very effective functional area for grinding the biomass that is more or less abrasive. Parts of two subsequent molars contribute to the “functional area of the dentition” (FAD). The FAD size, measured in cm², is associated with age and body size. The FAD stage is indicated by the specific teeth contributing to the FAD and represents the individual age. This study concentrates on Mammuthus primigenius and compares the FAD stages, as derived from growth series, with the fossil Elephas antiquus, as well as the extant Elephas maximus and Loxodonta africana. During the life history of the taxa studied, the functional area increases simultaneously with an increase in body size, but decreases severely in senile age stages. In some senile individuals, the FAD is only about 20–50 % of the mean area of an adult animal. The reduction of the FAD beyond a specific size does not mean an immediate starvation of the animal. The general constitution of the individual and the resources of fat accumulation earlier may support the animal for some time but certainly not over a longer period. Nevertheless, the highly reduced functional area was sufficient to keep the animal alive despite its full adult body mass. A much larger FAD in all adult stages provides the energy requirements needed for all additional life functions including competition and reproduction.
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Kurzfassung In der Zahnschmelz-Mikrostruktur der Inzisiven lassen sich die Hystricidae (Stachelschweine) mit ihren multiserialen Hunter-Schreger-Bändern (HSB) gut von den Castoridae (Biber) unterscheiden, die grundsätzlich uniseriale HSB... more
Kurzfassung In der Zahnschmelz-Mikrostruktur der Inzisiven lassen sich die Hystricidae (Stachelschweine) mit ihren multiserialen Hunter-Schreger-Bändern (HSB) gut von den Castoridae (Biber) unterscheiden, die grundsätzlich uniseriale HSB besitzen. Allerdings ist der Zahnschmelz der Biber nicht einheitlich aufgebaut. WährendPalaeocastor, Steneofiber undCastor recht typische uniseriale HSB besitzen, die nur beiCastor etwas miteinander verschmelzen, tritt diese Verschmelzung der HSB in der Gruppe umTrogontherium undCastoroides sehr
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Research Interests: Evolutionary Biology, Geology, Biology, Cyanobacteria, Ecology, and 5 moreTaphonomy, Algae, Seasonality, Volcano, and Algal Bloom
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The enamel microstructure in molars of Arsinoitherium is reinvestigated and a new modification of radial enamel (RE), ‘arsinoitheriid radial enamel (ARE)’, is defined. It is characterised by alternating stripes with different organisation... more
The enamel microstructure in molars of Arsinoitherium is reinvestigated and a new modification of radial enamel (RE), ‘arsinoitheriid radial enamel (ARE)’, is defined. It is characterised by alternating stripes with different organisation of the interprismatic matrix but no prism decussation. Recognition of this new subtype leads to a reinterpretation of structure previously identified as modified radial enamel and of Hunter–Schreger