Comment on "An early Miocene extinction in pelagic sharks".

Sibert and Rubin (Reports, 4 June 2021, p. 1105) claim to have identified a previously unidentified, major extinction event of open-ocean sharks in the early Miocene. We argue that their interpretations are based on an experimental design that does not account for a considerable rise in the sedimentation rate coinciding with the proposed event, nor for intraspecific variation in denticle morphology.

Fossil microbial shark tooth decay documents in situ metabolism of enameloid proteins as nutrition source in deep water environments.

Alteration of organic remains during the transition from the bio- to lithosphere is affected strongly by biotic processes of microbes influencing the potential of dead matter to become fossilized or vanish ultimately. If fossilized, bones, cartilage, and tooth dentine often display traces of bioerosion caused by destructive microbes. The causal agents, however, usually remain ambiguous.

[Comparative histopathologic and sonomorphological prostate studies].

Ten cadaver prostates were divided into 50 sections and corresponding sections were compared, using ultrasound, with respect to their echogenic structure and histomorphology. The results of normal prostatic tissues, benign prostatic hyperplasia and prostatic carcinomas are described and discussed. It was shown that malignant prostatic lesions showed echo-poor sonograms in vitro.