Während andere Kinder Fußball spielten, sammelte er Speckkäfer und schaute Tierskelette an. Seine Begeisterung für die Natur ließ Joseph Kälberer nie los. Heute ist er 29 Jahre und Tierpräparator am N...

Macroevolutionary adaptation of a continuous trait to different discrete states across species can be modelled using a phylogenetic state-dependent Ornstein–Uhlenbeck (OU) process. Existing infere...

In an experimental brood-size manipulation in Alpine swifts, smaller nestlings were selectively lost during growth, eliminating treatment differences in adult size, yet individuals from enlarged broo...

Pachyostosis, the increase in volume of bones, has been documented in a myriad of tetrapods that secondarily adapted to the aquatic environment. However, this convergent trait has hitherto only been quantified in complete ribs and long bones. This study presents a methodology designed to quantify the degree of pachyostosis in ribs and vertebrae for both complete and fragmentary skeletal elements. Using surface models, the volumes of costal and vertebral regions were measured and standardized using size proxies to devise a pachyostosis index. Sirenians are used as a case study, given the disparity in pachyostosis degrees that has already been documented in the clade, especially in their ribs. The new methodology can detect this disparity and further demonstrates that pachyostosis also affects their vertebrae. Milder cases of pachyostosis, such as in the extant Dugong dugon, are likely secondary specializations to a specific lifestyle. The craniocaudal distribution of the pachyostosis index values is also potentially helpful for further distinguishing finer lifestyle differences. This new method has the potential to clarify the causes of the disparity in pachyostosis degrees observed in the fossil record of sirenians, and it may also prove valuable in broader, non-mammalian contexts.

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