Abstract
We report a fossil snake from the middle Eocene (48 Ma) Messel Pit, in whose stomach is a lizard, in whose stomach is an insect. This is the second known vertebrate fossil containing direct evidence of three trophic levels. The snake is identified as a juvenile of Palaeopython fischeri on the basis of new characters of the skull; the lizard is identified as Geiseltaliellus maarius, a stem-basilisk; and the insect, despite preserved structural colouration, could not be identified more precisely. G. maarius is thought to have been an arboreal species, but like its extant relatives may have foraged occasionally on the ground. Another, larger specimen of G. maarius preserves plant remains in the digestive tract, suggesting that omnivory in this species may have been common in larger individuals, as in extant Basiliscus and Polychrus. A general picture of the trophic ecology of P. fischeri is not yet possible, although the presence of a lizard in the stomach of a juvenile individual suggests that this snake could have undergone a dietary shift, as in many extant boines.
Keywords: Messel, Middle Eocene, Palaeopython fischeri, Geiseltaliellus maarius, Gut contents, Food chain
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| Fig. 1 SMF ME 11332a, comprising a juvenile specimen of the snake Palaeopython fischeri and its prey. Arrow points to the tip of the snout of the lizard inside the snake |
Conclusions
In conjunction with dietary data on extant basilisks (Corytophaninae) and phylogenetic position, the consumption of plant matter by larger individuals of G. maarius, an early stem relative of Corytophaninae (Smith 2009), suggests that this propensity might be primitive for Corytophaninae or Corytophaninae + (Polychrus + Anolis) as a whole. This interpretation would be strengthened if Conrad’s (2015) view of the relationships of Geiseltaliellus is correct. Available data suggest dietary shift from insectory to omnivory in G. maarius.
Similarly, in conjunction with the presence of a crocodile in the large boid specimen from Messel studied by Greene (1983), the presence of an arboreal lizard in the alimentary canal of a juvenile individual of P. fischeri indicates that this dietary preference during juvenile stages and perhaps an ontogenetic dietary shift was present in boid snakes since the middle Eocene.
Krister T. Smith and Agustín Scanferla. 2016. Fossil Snake Preserving Three Trophic Levels and Evidence for An Ontogenetic Dietary Shift. Palaeobiodiversity and Palaeoenvironments. DOI: 10.1007/s12549-016-0244-1
Amazing ‘Nesting Doll’ Fossil Reveals Bug in Lizard in Snake https://t.co/Do3D4ggFdl via @NatGeo A Messel Turducken!!
