Skull dimension measurements from two museum collections
We included detailed data on skull dimensions and body mass of S.
araneus from two populations: Žofín, in the Novohradské hory mountain
range (Czech Republic; 48.671838, 14.690402; new data) from the dry
collection deposited at the Department of Zoology at the Charles
University in Prague, which were collected from 1971 to 1977; and
Białowieża National Park (Poland; 52.700000, 23.866667; Dechmann et al.
2017) at the Mammal Research Institute Polish Academy of Sciences. These
specimens were collected in Białowieża National Park in 1946-1947, and
also preserved dry. We used digital calipers (±0.01 mm) to obtain
braincase height, from the tympanic rings to the dorsal surface of the
braincase, skull length, from the anteriormost projection of incisor 1
to the occipital condyle, maximum braincase width, and lower mandible
length, from the alveolus dentalis of the incisor to the coronoid
process. We focused our analyses on braincase height as we had
previously found it to show the greatest change in response to Dehnel’s
Phenomenon (Lázaro et al. , 2017, 2018a).