Thursday, November 24, 2016

[Paleontology • 2016] Janosikia ulmensis • Fossil Lizard from central Europe Resolves the Origin of Large Body Size and Herbivory in Giant Canary Island Lacertids

Janosikia ulmensis   (Gerhardt, 1903).
DOI:  10.1111/zoj.12340  

The endemic Canary Island lizard clade Gallotia, which includes the largest members of Europe's dominant reptile group, Lacertidae, is one of the classic examples of insular gigantism. For the first time we use fossil data to test the evolutionary reasons for the association between gigantism and herbivory. We describe an almost completely preserved skeleton of Janosikia ulmensis  comb. nov. from the early Miocene of Ulm, Germany (MN 2a, ∼ 22 Mya). We show that this species and Oligocene Pseudeumeces cadurcensis (Filhol, 1877) are in fact crown lacertids, and the first known pre-Quaternary record of the total clade of Gallotia. Pseudeumeces confirms the early origin of crown Lacertidae in the Palaeogene of Europe. More importantly, these fossil taxa show that large body size was already achieved on the European mainland by the early Miocene. Furthermore, Pseudeumeces and Janosikia were faunivorous, thus demonstrating that insularity, not large body size, was crucial to the evolution of herbivory in this lineage. Body size change in Gallotia was more complex than previously thought, encompassing size increase [e.g. in the extinct Gallotia goliath (Mertens, 1942)], but more commonly involving miniaturization. The physical environment may play a crucial role in modulating the evolution of body size in this natural laboratory.

Keywords: Canary Islands; Europe; island rule; lacertid phylogeny– Palaeogene; Squamata

Systematic Palaeontology
Squamata Oppel, 1811 
Lacertidae Oppel, 1811 

Gallotiinae Cano, Baez, López-Jurado & Ortega, 1984 

Janosikia gen. nov.

Etymology: After Juraj Jánošík (20? January 1688–17 March 1713), famed leader of a Slovak band of highwaymen. They took from the rich and gave to the poor, but did not kill and even helped an injured priest. Jánošík was eventually captured and executed.

Type species: Janosikia ulmensis comb. nov. (Gerhardt, 1903).

Comment: Based on our phylogenetic analyses (see below), a new generic name is required for this species despite its similarity to Pseudeumeces cadurcensis. The attribution of the species to Pseudeumeces would render the latter paraphyletic.

Janosikia ulmensis (Gerhardt, 1903) comb. nov.  

Locality and horizon: Type locality of Ophisaurus ulmensis Gerhardt, 1903, north-west of Ulm, Germany. The fossils derive from white or grey calcareous marls of the of the Lower Freshwater Molasse, dated to the middle Agenian (MN 2a), lower Miocene (Heizmann et al., 1989).

Figure 3.  Janosikia ulmensis  comb. nov., SMNS 96582.
 A, main prepared block of sediment, containing most cranial elements. B, reconstruction of the skull in dorsal view. C, life reconstruction of J. ulmensis comb. nov. from the early Miocene of Germany. 

Figure 9.  A, phylogenetic relationships of Pseudeumeces and Janosikia gen. nov. with other lacertid lizards. Single most-parsimonious tree. Bootstrap values shown on branches subtending nodes. B, evolution of size in Gallotiinae. Average skull size (and so average body size) increases progressively on stem of Gallotia, such that Janosikia ulmensis comb. nov. equals basal Gallotia stehlini in size. Skull size decreases several times in Gallotia, including Gallotia atlantica and the Gallotia galloti group. Nodes 1 (Gallotiinae), 2, 3, and 4 (Gallotia) are labelled. 


 Andrej Čerňanský, Jozef Klembara and Krister T. Smith. 2016. Fossil Lizard from central Europe Resolves the Origin of Large Body Size and Herbivory in Giant Canary Island Lacertids. Zoological Journal of the Linnean Society. 176(4); 861–877. DOI:  10.1111/zoj.12340 

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