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| Eoconstrictor barnesi in the Geiseltal palaeoenvironment, trying to capture a small leptictidan mammal Palci, Onary, Lee, Smith, Wings, Rabi & Georgalis, 2023 Life reconstruction by Márton Szabó |
Abstract
We describe two exceptionally preserved fossil snakes from the Eocene Konservat-Lagerstätte of Geiseltal, located in the state of Saxony-Anhalt, Germany. The two snake specimens, GMH LIX-3-1992 and GMH XXXVIII-20-1964, can be confidently identified as booids based on general morphology and were thus compared to other geographically and/or temporally close fossil booids. We found that GMH LIX-3-1992 is morphologically very similar to Eoconstrictor spinifer, also from Geiseltal, and to Eoconstrictor fischeri, from the middle Eocene of Messel, but differs from both in a number of cranial and vertebral features. Based on these differences we erect the new species Eoconstrictor barnesi sp. nov.; GMH XXXVIII-20-1964 is very similar to GMH LIX-3-1992 and the two differ only in features that are likely ontogenetic. Phylogenetic analyses of snakes using maximum parsimony and Bayesian inference on datasets inclusive of both morphological and molecular data consistently support a close affinity of E. barnesi to E. fischeri and E. spinifer. Our preferred phylogenetic hypothesis places the three species of Eoconstrictor in a clade that is sister to Neotropical Boidae, a result consistent with previous studies. The genus Eoconstrictor could provide an important calibration point for molecular clock studies of booids and snakes in general.
Eocene, evolution, computed tomography, phylogeny, Serpentes
SYSTEMATIC PALAEONTOLOGY
Squamata Oppel, 1811a
Serpentes Linnaeus, 1758
Constrictores Oppel, 1811b (sensu Georgalis and Smith 2020)
Booidea Gray, 1825 (sensu Pyron et al. 2014)
Genus Eoconstrictor Scanferla & Smith, 2020a
Type species: Palaeopython fischeri Schaal, 2004 (original combination), currently Eoconstrictor fischeri (Schaal, 2004) following the work of Scanferla and Smith (2020a).
Type species locality and age: Messel Pit, Germany (Smith et al. 2018). All known specimens of E. fischeri come from the lacustrine ‘oil-shale’ of the Middle Messel Formation (near the Ypresian–Lutetian boundary, ~48 Mya) (Lenz et al. 2015).
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| Eoconstrictor barnesi, GMH XXXVIII-20-1964, holotype. A, View of the specimen as preserved, insets show clusters of vertebrae that are preserved on the same slab but a few centimetres away from the rest of the body; (B) close-up of the skull in dorsal view and disarticulated left lower jaw in lateral view; (C) close-up of three mid-trunk vertebrae in ventral view; (D) close-up of two posterior trunk vertebrae in ventral view; (E) close-up of four mid-trunk vertebrae in left lateral view; (F) close-up of four mid-trunk vertebrae in dorsal view. |
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| Eoconstrictor barnesi, GMH LIX-3-1992, paratype. A, View of the specimen as preserved; (B) close-up of the skull in left lateral view; (C) close-up of three precloacal vertebrae in ventral view; (D) close-up of five precloacal vertebrae in left dorsolateral and dorsal views. |
Eoconstrictor barnesi sp. nov.
Etymology: Species epithet honouring Ben Barnes, who pioneered palaeontological excavations and research in the brown coal deposits of Geiseltal in the 1920s, as part of his Ph.D. studies at the Geological Institute of Halle (Saale).
Holotype: GMH XXXVIII-20-1964, a partial skull and partially disarticulated skeleton missing only the most anterior precloacal region, the cloacal region, and most of the tail (Figs 2–5, Supporting Information, File S1: Fig. S1).
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| Life reconstruction of Eoconstrictor barnesi in the Geiseltal palaeoenvironment, trying to capture a small leptictidan mammal (artwork by Márton Szabó). |
Alessandro Palci, Silvio Onary, Michael S Y Lee, Krister T Smith, Oliver Wings, Márton Rabi and Georgios L Georgalis. 2023. A New booid Snake from the Eocene (Lutetian) Konservat-Lagerstätte of Geiseltal, Germany, and A New Phylogenetic Analysis of Booidea. Zoological Journal of the Linnean Society. zlad179. DOI: 10.1093/zoolinnean/zlad179
