Vassilis Kypraios-Skrekas, Sinos Giokas, Evanthia Thanou

1. So close no matter how far: sympatric slow
worm lizards look alike but share little else
Vassilis Kypraios-Skrekas, Sinos Giokas,
Evanthia Thanou*
Virtual Meeting of Systematics, Biogeography and Evolution
28-30 July 2020
Dep. of Biology, University of Patras, Greece
* Corresponding author: thanouevanthia@gmail.com
This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the
Operational Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the
context of the project “Phylogeography in the genomics era and the role of barriers in speciation (MIS 5047129)”

2. Introduction
• Anguis greaca and A. cephallonica are Balkan endemics, originally treated as
conspecifics due to morphological similarity and co-distribution.
• mtDNA phylogenies1,2,3 show 2 distinct lineages that possibly reached secondary
contact after past population expansion
• However, the question remains. Could morphological similarity and
co-distribution reflect common ancenstry or convergent evolution?
A. cephallonica
A. greaca
1. Gvozdic et al. 2010, MPE 55:460-472; 2. Thanou et al. 2014, Amph-Rept , 35:263-269; 3. Jablonsky et al. 2016, BMC Evol. Biol, 16:99-117
ImagesfromGvozdicetal.
2013,MPE69:1077-1092.
Here we tested two hypotheses:
1. Morphological similarity suggests gene flow
and hybridization between the two lineages.
2. Co-distribution suggests similar environmental
preferences and convergent evolution.

3. Materials & Methods
• 37 ddRAD libraries of A. cephallonica and A. graeca; approx.
75K sites in total, 4K loci and 1,000 unlinked SNPs per lineage
• ML phylogeny (IQ-tree, SVDquartets) with genomic markers
compared to known mtDNA phylogenies
• Test for admixture between lineages and population structure
within (hierarchical STRUCTURE analyses, DAPC); test for
Isolation-By-Distance (IBD; Mantel tests)
• Test for niche overlap and predict distribution maps based on
19 bioclimatic variables with Species Distribution Models
(SDM; Maxent analysis on 181 occurrence points)

4. Results & Discussion
Congruent mtDNA and genomic phylogenies
No admixture between cephallonica & greaca
Gene flow within each lineage
Population structure reflects IBD
A. cephallonica
P<0.00001
A. greaca
P<0.001
Regression plots of Genetic distances vs. Geographic distances

5. Conclusion
No niche overlap (Schoener's D = 0.47)
Both lizards’ distribution is associated with high
precipitation
Only A. greaca distribution is restricted by high
temperatures (30% contribution to SDM)
Results & Discussion
We reject both hypotheses of genetic admixture and niche convergence.
Most plausible explanation: morphological similarity due to retained ancient traits.
Next step: extensive morphometric comparisons!
A. cephallonica
AUC= 0.87
A. greaca
AUC= 0.81
- 0.2
- 0.8