A new species of Palaeopython (Serpentes) and other extinct squamates from the Eocene of Dielsdorf (Zurich, Switzerland)

Abstract

The lizard and snake fauna from the late middle-late Eocene (MP 16-MP 20) of Dielsdorf, near Zurich, Switzerland, is described comprehensively in this paper. Detailed comparisons of the Dielsdorf material with other extinct taxa allow us to establish a new species of the large ''booid'' genus Palaeopython, i.e., Palaeopython helveticus sp. nov., characterized by a unique combination of vertebral features, most prominently a highly vaulted neural arch. Other squamates of the Dielsdorf assemblage comprise the large lizard Palaeovaranus sp. and as many as three other taxa of snakes, i.e., Palaeopython cf. fischeri, Palaeopython sp. (morphotype 3), and ''Booidea'' indet. We conducted micro-CT scanning in the Palaeovaranus dentary, which confirmed the presence of plicidentine in this lizard genus. Micro-CT scanning was also conducted in differently sized snake vertebrae from our sample, revealing that the respective anatomical differences were probably due to ontogenetic variation. This is the first time that micro-CT scanning is applied in Palaeovaranus and Palaeopython. The importance of this method for potentially clarifying the taxonomy and precise affinities of extinct snakes is addressed. We also provide digital 3D model reconstructions of the Palaeovaranus dentary and Palaeopython vertebrae (including that of the holotype of Palaeopython helveticus sp. nov.) for the first time. The palaeobiogeographic significance of the Dielsdorf lizards and snakes is discussed and the sympatric occurrences of the genera Palaeovaranus and Palaeopython throughout the Eocene of Europe are presented in detail.

Exquisitely Preserved Fossil Snakes of Messel: Insight into the Evolution, Biogeography, Habitat Preferences and Sensory Ecology of Early Boas

“…Remarks: Currently all larger "booid" vertebrae from the early Palaeogene of Europe have been referred to species of the genera Palaeopython or Paleryx [31]. However, ongoing revision of these genera based on the type material, including cranial elements, shows that "Palaeopython" fischeri is not closely related to the type species of Palaeopython, P. cadurcensis, and lacks diagnostic features of the type species of Paleryx, P. rhombifer.…”

Oldest co-occurrence ofVaranusandPythonfrom Africa—first record of squamates from the early Miocene of Moghra Formation, Western Desert, Egypt

“…The sympatry of Varanus and Python across the Neogene of Africa, continuing also up to today, is reminiscent of other such cases of large lizards and snakes coexisting together across large geographic distances and stratigraphic spans during the Cenozoic. Such is the case of Palaeovaranus and Palaeopython found together in multiple localities across the Eocene of Western and Central Europe (see Georgalis & Scheyer, 2019), a case that rather amusingly fits also ''euphoniously'' to the case of sympatry of Varanus and Python. Rögl (1999), with data also from Popov et al (2004).…”

A new early Miocene herpetofauna from Kilçak, Turkey

“…In any case, the identification of Bavarioboa in Kilçak provides the first stratigraphically definite evidence of the presence of this snake genus in the earliest Miocene (MN 1) and furthermore confirms its more widespread distribution in Eastern Mediterranean. As for the exact affinities of Bavarioboa, although it was originally and often placed into Boidae and more precisely close to boines, on the basis of the frequent presence of paracotylar foramina, recent advances in the taxonomy of boas and pythons have prompted for a more reluctant systematic assignments of most fossil "booids" from the Cenozoic of Europe (see Georgalis and Scheyer, 2019).…”