TY  - CONF
AU  - Urošević, Aleksandar
AU  - Ajduković, Maja
AU  - Vučić, Tijana
AU  - Scholtes, Stefan
AU  - Arntzen, Jan
AU  - Ivanović, Ana
PY  - 2022
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/5231
AB  - Serially homologous structures, such as the vertebral column, often undergo 
functional and evolutionary diversification and are a good model-system for studies of 
regionalization and morphological integration. We studied these topics in the vertebral 
column (atlas, trunk and sacral vertebrae) of the closely related taxa of small-bodied 
newts – Lissotriton schmidtleri, L. vulgaris ampelensis, L. v. meridionalis and L. v. 
vulgaris, using 3D geometric morphometrics on models that were acquired with micro CT scanning. Two different statistical approaches were employed to test for vertebral 
regionalization and overall morphological integration, namely segmented linear 
regression (SLR) and a partial least squares method (PLS) We observed a common 
pattern of regionalization, with a transition point after the 5th trunk vertebra. It 
corresponds with the antero-posterior transition common for tetrapods. 
Morphological integration, accessed via PLS analysis, is strongest at the 6th and 7th
trunk vertebrae, while the anterior and distal parts of the vertebral column are less 
integrated. The PLS analysis of the asymmetric component of shape variation revealed 
a weak integration, statistically significant only among subsequent trunk vertebrae. In 
summary, the vertebral column of the closely related Lissotriton newts is subtly 
regionalized, while being morphologically integrated overall. There is a complex 
relationship between regionalization and morphological integration of the vertebral 
column, most likely influenced by the newt’s bi-phasic life cycle that instigates different 
functional constraints in the aquatic and terrestrial life stages
PB  - Belgrade: Institute for Biological Research "Siniša Stanković"– National Institute of Republic of Serbia, University of Belgrade
C3  - Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia
T1  - Vertebral regionalization vs. morphological integration in Lissotriton newts
SP  - 38
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_5231
ER  - 

@conference{
author = "Urošević, Aleksandar and Ajduković, Maja and Vučić, Tijana and Scholtes, Stefan and Arntzen, Jan and Ivanović, Ana",
year = "2022",
abstract = "Serially homologous structures, such as the vertebral column, often undergo 
functional and evolutionary diversification and are a good model-system for studies of 
regionalization and morphological integration. We studied these topics in the vertebral 
column (atlas, trunk and sacral vertebrae) of the closely related taxa of small-bodied 
newts – Lissotriton schmidtleri, L. vulgaris ampelensis, L. v. meridionalis and L. v. 
vulgaris, using 3D geometric morphometrics on models that were acquired with micro CT scanning. Two different statistical approaches were employed to test for vertebral 
regionalization and overall morphological integration, namely segmented linear 
regression (SLR) and a partial least squares method (PLS) We observed a common 
pattern of regionalization, with a transition point after the 5th trunk vertebra. It 
corresponds with the antero-posterior transition common for tetrapods. 
Morphological integration, accessed via PLS analysis, is strongest at the 6th and 7th
trunk vertebrae, while the anterior and distal parts of the vertebral column are less 
integrated. The PLS analysis of the asymmetric component of shape variation revealed 
a weak integration, statistically significant only among subsequent trunk vertebrae. In 
summary, the vertebral column of the closely related Lissotriton newts is subtly 
regionalized, while being morphologically integrated overall. There is a complex 
relationship between regionalization and morphological integration of the vertebral 
column, most likely influenced by the newt’s bi-phasic life cycle that instigates different 
functional constraints in the aquatic and terrestrial life stages",
publisher = "Belgrade: Institute for Biological Research "Siniša Stanković"– National Institute of Republic of Serbia, University of Belgrade",
journal = "Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia",
title = "Vertebral regionalization vs. morphological integration in Lissotriton newts",
pages = "38",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_5231"
}

Urošević, A., Ajduković, M., Vučić, T., Scholtes, S., Arntzen, J.,& Ivanović, A.. (2022). Vertebral regionalization vs. morphological integration in Lissotriton newts. in Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia
Belgrade: Institute for Biological Research "Siniša Stanković"– National Institute of Republic of Serbia, University of Belgrade., 38.
https://hdl.handle.net/21.15107/rcub_ibiss_5231

Urošević A, Ajduković M, Vučić T, Scholtes S, Arntzen J, Ivanović A. Vertebral regionalization vs. morphological integration in Lissotriton newts. in Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia. 2022;:38.
https://hdl.handle.net/21.15107/rcub_ibiss_5231 .

Urošević, Aleksandar, Ajduković, Maja, Vučić, Tijana, Scholtes, Stefan, Arntzen, Jan, Ivanović, Ana, "Vertebral regionalization vs. morphological integration in Lissotriton newts" in Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia (2022):38,
https://hdl.handle.net/21.15107/rcub_ibiss_5231 .

TY  - CONF
AU  - Cvijanović, Milena
AU  - Ajduković, Maja
AU  - Ivanović, Ana
AU  - Arntzen, Jan
PY  - 2022
UR  - http://radar.ibiss.bg.ac.rs/handle/123456789/5134
AB  - In the skin of many terrestrial anuran taxa, a specific acellular mineralized tissue
layer (the Eberth-Katschenko layer) has been documented. This layer is generally
positioned in between the stratum spongiosum and the stratum compactum of the
dermis and has a role in reducing water loss. Here, we document and compare the
amount of calcium deposition in the skin of the head and the parotoids (the external
skin glands) in males and females of the common toad Bufo bufo and the spined toad B.
spinosus. Bufo bufo and B. spinosus are morphologically similar and both show a
conspicuous sexual dimorphism. Using standard histological techniques, we detected
calcium as an amorphous ‘ground substance’ located in the stratum spongiosum, just
above the Eberth-Katschenko layer. We observed large variability in the number of
calcium deposits between the species and the sexes. Using micro-computed
tomography (micro-CT) we were able to quantify the level of the toad skin calcification.
Bufo spinosus females stand out compared to conspecific males and B. bufo on account
of a strong calcification of the dorsal and ventral skin and the parotoid glands. Species
and sexes significantly differed in the amount of calcium deposits (Fisher’s exact test,
p < 0.001) and pairwise comparisons showed that groups differed from one another (p
< 0.05), suggesting size and sexual dimorphism in these traits. We conclude that microCT scanning is useful for the quantification of calcified structures in the anuran skin,
and keeps a promise for further studies on taxonomic and geographic variation.
PB  - Belgrade: Institute for Biological Research "Siniša Stanković"– National Institute of Republic of Serbia, University of Belgrade
C3  - Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia
T1  - What is hiding in the Bufo skin? Revealing of the structures in the skin of European toads using standard histological and micro-CT techniques
SP  - 32
UR  - https://hdl.handle.net/21.15107/rcub_ibiss_5134
ER  - 

@conference{
author = "Cvijanović, Milena and Ajduković, Maja and Ivanović, Ana and Arntzen, Jan",
year = "2022",
abstract = "In the skin of many terrestrial anuran taxa, a specific acellular mineralized tissue
layer (the Eberth-Katschenko layer) has been documented. This layer is generally
positioned in between the stratum spongiosum and the stratum compactum of the
dermis and has a role in reducing water loss. Here, we document and compare the
amount of calcium deposition in the skin of the head and the parotoids (the external
skin glands) in males and females of the common toad Bufo bufo and the spined toad B.
spinosus. Bufo bufo and B. spinosus are morphologically similar and both show a
conspicuous sexual dimorphism. Using standard histological techniques, we detected
calcium as an amorphous ‘ground substance’ located in the stratum spongiosum, just
above the Eberth-Katschenko layer. We observed large variability in the number of
calcium deposits between the species and the sexes. Using micro-computed
tomography (micro-CT) we were able to quantify the level of the toad skin calcification.
Bufo spinosus females stand out compared to conspecific males and B. bufo on account
of a strong calcification of the dorsal and ventral skin and the parotoid glands. Species
and sexes significantly differed in the amount of calcium deposits (Fisher’s exact test,
p < 0.001) and pairwise comparisons showed that groups differed from one another (p
< 0.05), suggesting size and sexual dimorphism in these traits. We conclude that microCT scanning is useful for the quantification of calcified structures in the anuran skin,
and keeps a promise for further studies on taxonomic and geographic variation.",
publisher = "Belgrade: Institute for Biological Research "Siniša Stanković"– National Institute of Republic of Serbia, University of Belgrade",
journal = "Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia",
title = "What is hiding in the Bufo skin? Revealing of the structures in the skin of European toads using standard histological and micro-CT techniques",
pages = "32",
url = "https://hdl.handle.net/21.15107/rcub_ibiss_5134"
}

Cvijanović, M., Ajduković, M., Ivanović, A.,& Arntzen, J.. (2022). What is hiding in the Bufo skin? Revealing of the structures in the skin of European toads using standard histological and micro-CT techniques. in Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia
Belgrade: Institute for Biological Research "Siniša Stanković"– National Institute of Republic of Serbia, University of Belgrade., 32.
https://hdl.handle.net/21.15107/rcub_ibiss_5134

Cvijanović M, Ajduković M, Ivanović A, Arntzen J. What is hiding in the Bufo skin? Revealing of the structures in the skin of European toads using standard histological and micro-CT techniques. in Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia. 2022;:32.
https://hdl.handle.net/21.15107/rcub_ibiss_5134 .

Cvijanović, Milena, Ajduković, Maja, Ivanović, Ana, Arntzen, Jan, "What is hiding in the Bufo skin? Revealing of the structures in the skin of European toads using standard histological and micro-CT techniques" in Program and Book of Abstracts: the 21st European Congress of Herpetology; 2022 Sep 5-9; Belgrade, Serbia (2022):32,
https://hdl.handle.net/21.15107/rcub_ibiss_5134 .

TY  - JOUR
AU  - Scholtes, Stefan
AU  - Arntzen, Jan
AU  - Ajduković, Maja
AU  - Ivanović, Ana
PY  - 2021
UR  - https://radar.ibiss.bg.ac.rs/handle/123456789/4660
AB  - The salamander vertebral column is largely undifferentiated, with a series of more or less uniform rib bearing presacral vertebrae traditionally designated as the trunk region. We explored regionalisation of the salamander trunk in seven species and two subspecies of the salamander genus Lissotriton by the combination of micro computed tomography scanning and geometric morphometrics. The detailed information on trunk vertebral shape was subjected to a multidimensional cluster analysis and a phenotypic trajectory analysis. With these complementary approaches, we observed a clear morphological regionalization. Clustering analysis showed that the anterior trunk vertebrae (T1 and T2) have distinct morphologies that are shared by all taxa, whereas the subsequent, more posterior vertebrae show significant disparity between species. The phenotypic trajectory analysis revealed that all taxa share a common pattern and amount of shape change along the trunk region. Altogether, our results support the hypothesis of a conserved anterior-posterior developmental patterning which can be associated with different functional demands, reflecting (sub)species’ and possibly, regional ecological divergences within species.
PB  - Hoboken: Wiley
T2  - Journal of Anatomy
T1  - Variation in vertebrae shape across small-bodied newts reveals functional and developmental constraints acting upon the trunk region
DO  - 10.1111/joa.13591
ER  - 

@article{
author = "Scholtes, Stefan and Arntzen, Jan and Ajduković, Maja and Ivanović, Ana",
year = "2021",
abstract = "The salamander vertebral column is largely undifferentiated, with a series of more or less uniform rib bearing presacral vertebrae traditionally designated as the trunk region. We explored regionalisation of the salamander trunk in seven species and two subspecies of the salamander genus Lissotriton by the combination of micro computed tomography scanning and geometric morphometrics. The detailed information on trunk vertebral shape was subjected to a multidimensional cluster analysis and a phenotypic trajectory analysis. With these complementary approaches, we observed a clear morphological regionalization. Clustering analysis showed that the anterior trunk vertebrae (T1 and T2) have distinct morphologies that are shared by all taxa, whereas the subsequent, more posterior vertebrae show significant disparity between species. The phenotypic trajectory analysis revealed that all taxa share a common pattern and amount of shape change along the trunk region. Altogether, our results support the hypothesis of a conserved anterior-posterior developmental patterning which can be associated with different functional demands, reflecting (sub)species’ and possibly, regional ecological divergences within species.",
publisher = "Hoboken: Wiley",
journal = "Journal of Anatomy",
title = "Variation in vertebrae shape across small-bodied newts reveals functional and developmental constraints acting upon the trunk region",
doi = "10.1111/joa.13591"
}

Scholtes, S., Arntzen, J., Ajduković, M.,& Ivanović, A.. (2021). Variation in vertebrae shape across small-bodied newts reveals functional and developmental constraints acting upon the trunk region. in Journal of Anatomy
Hoboken: Wiley..
https://doi.org/10.1111/joa.13591

Scholtes S, Arntzen J, Ajduković M, Ivanović A. Variation in vertebrae shape across small-bodied newts reveals functional and developmental constraints acting upon the trunk region. in Journal of Anatomy. 2021;.
doi:10.1111/joa.13591 .

Scholtes, Stefan, Arntzen, Jan, Ajduković, Maja, Ivanović, Ana, "Variation in vertebrae shape across small-bodied newts reveals functional and developmental constraints acting upon the trunk region" in Journal of Anatomy (2021),
https://doi.org/10.1111/joa.13591 . .

TY  - JOUR
AU  - Urošević, Aleksandar
AU  - Ajduković, Maja
AU  - Arntzen, Jan W.
AU  - Ivanović, Ana
PY  - 2020
UR  - https://radar.ibiss.bg.ac.rs/handle/123456789/3617
AB  - Serial homology or the repetition of equivalent developmental units and their derivatives is a phenomenon encountered in a variety of organisms, with the vertebrate axial skeleton as one of the most notable examples. Serially homologous structures can be viewed as an appropriate model system for studying morphological integration and modularity, due to the strong impact of development on their covariation. Here, we explored the pattern of morphological integration of the cranium and the first three serially homologous structures (atlas, first, and second trunk vertebrae) in salamandrid salamanders, using micro‐CT scanning and three‐dimensional geometric morphometrics. We explored the integration between structures at static and evolutionary levels. Effects of allometry on patterns of modularity were also taken into account. At the static level (within species), we analyzed inter‐individual variation in shape to detect functional modules and intra‐individual variation to detect developmental modules. Significant integration (based on inter‐individual variation) among all structures was detected and allometry is shown to be an important integrating factor. The pattern of intra‐individual, asymmetric variation indicates statistically significant developmental integration between the cranium and the atlas and between the first two trunk vertebrae. At the evolutionary level (among species), the cranium, atlas, and trunk vertebrae separate as different modules. Our results show that morphological integration at the evolutionary level coincides with morphological and functional differentiation of the axial skeleton, allowing the more or less independent evolutionary changes of the cranial skeleton and the vertebral column, regardless of the relatively strong integration at the static level. The observed patterns of morphological integration differ across levels, indicating different impacts of developmental and phylogenetic constraints and functional demands.
PB  - Wiley
T2  - Journal of Zoological Systematics and Evolutionary Research
T1  - Morphological integration and serial homology: A case study of the cranium and anterior vertebrae in salamanders
IS  - 4
VL  - 58
DO  - 10.1111/jzs.12374
SP  - 1206
EP  - 1219
ER  - 

@article{
author = "Urošević, Aleksandar and Ajduković, Maja and Arntzen, Jan W. and Ivanović, Ana",
year = "2020",
abstract = "Serial homology or the repetition of equivalent developmental units and their derivatives is a phenomenon encountered in a variety of organisms, with the vertebrate axial skeleton as one of the most notable examples. Serially homologous structures can be viewed as an appropriate model system for studying morphological integration and modularity, due to the strong impact of development on their covariation. Here, we explored the pattern of morphological integration of the cranium and the first three serially homologous structures (atlas, first, and second trunk vertebrae) in salamandrid salamanders, using micro‐CT scanning and three‐dimensional geometric morphometrics. We explored the integration between structures at static and evolutionary levels. Effects of allometry on patterns of modularity were also taken into account. At the static level (within species), we analyzed inter‐individual variation in shape to detect functional modules and intra‐individual variation to detect developmental modules. Significant integration (based on inter‐individual variation) among all structures was detected and allometry is shown to be an important integrating factor. The pattern of intra‐individual, asymmetric variation indicates statistically significant developmental integration between the cranium and the atlas and between the first two trunk vertebrae. At the evolutionary level (among species), the cranium, atlas, and trunk vertebrae separate as different modules. Our results show that morphological integration at the evolutionary level coincides with morphological and functional differentiation of the axial skeleton, allowing the more or less independent evolutionary changes of the cranial skeleton and the vertebral column, regardless of the relatively strong integration at the static level. The observed patterns of morphological integration differ across levels, indicating different impacts of developmental and phylogenetic constraints and functional demands.",
publisher = "Wiley",
journal = "Journal of Zoological Systematics and Evolutionary Research",
title = "Morphological integration and serial homology: A case study of the cranium and anterior vertebrae in salamanders",
number = "4",
volume = "58",
doi = "10.1111/jzs.12374",
pages = "1206-1219"
}

Urošević, A., Ajduković, M., Arntzen, J. W.,& Ivanović, A.. (2020). Morphological integration and serial homology: A case study of the cranium and anterior vertebrae in salamanders. in Journal of Zoological Systematics and Evolutionary Research
Wiley., 58(4), 1206-1219.
https://doi.org/10.1111/jzs.12374

Urošević A, Ajduković M, Arntzen JW, Ivanović A. Morphological integration and serial homology: A case study of the cranium and anterior vertebrae in salamanders. in Journal of Zoological Systematics and Evolutionary Research. 2020;58(4):1206-1219.
doi:10.1111/jzs.12374 .

Urošević, Aleksandar, Ajduković, Maja, Arntzen, Jan W., Ivanović, Ana, "Morphological integration and serial homology: A case study of the cranium and anterior vertebrae in salamanders" in Journal of Zoological Systematics and Evolutionary Research, 58, no. 4 (2020):1206-1219,
https://doi.org/10.1111/jzs.12374 . .

TY  - JOUR
AU  - Dufresnes, Christophe
AU  - Strachinis, Ilias
AU  - Suriadna, Nataliia
AU  - Mykytynets, Galyna
AU  - Cogălniceanu, Dan
AU  - Székely, Paul
AU  - Vukov, Tanja
AU  - Arntzen, Jan W.
AU  - Wielstra, Ben
AU  - Lymberakis, Petros
AU  - Geffen, Eli
AU  - Gafny, Sarig
AU  - Kumlutaş, Yusuf
AU  - Ilgaz, Çetin
AU  - Candan, Kamil
AU  - Mizsei, Edvárd
AU  - Szabolcs, Márton
AU  - Kolenda, Krzysztof
AU  - Smirnov, Nazar
AU  - Géniez, Philippe
AU  - Lukanov, Simeon
AU  - Crochet, Pierre-André
AU  - Dubey, Sylvain
AU  - Perrin, Nicolas
AU  - Litvinchuk, Spartak N.
AU  - Denoël, Mathieu
PY  - 2019
UR  - http://doi.wiley.com/10.1111/mec.15133
UR  - https://radar.ibiss.bg.ac.rs/handle/123456789/3412
AB  - Cryptic phylogeographic diversifications provide unique models to examine the role of phylogenetic divergence on the evolution of reproductive isolation, without extrinsic factors such as ecological and behavioural differentiation. Yet, to date very few comparative studies have been attempted within such radiations. Here, we characterize a new speciation continuum in a group of widespread Eurasian amphibians, the Pelobates spadefoot toads, by conducting multilocus (restriction site associated DNA sequencing and mitochondrial DNA) phylogenetic, phylogeographic and hybrid zone analyses. Within the P. syriacus complex, we discovered species-level cryptic divergences (>5 million years ago [My]) between populations distributed in the Near-East (hereafter P. syriacus sensu stricto [s.s.]) and southeastern Europe (hereafter P. balcanicus), each featuring deep intraspecific lineages. Altogether, we could scale hybridizability to divergence time along six different stages, spanning from sympatry without gene flow (P. fuscus and P. balcanicus, >10 My), parapatry with highly restricted hybridization (P. balcanicus and P. syriacus s.s., >5 My), narrow hybrid zones (~15 km) consistent with partial reproductive isolation (P. fuscus and P. vespertinus, ~3 My), to extensive admixture between Pleistocene and refugial lineages (≤2 My). This full spectrum empirically supports a gradual build up of reproductive barriers through time, reversible up until a threshold that we estimate at ~3 My. Hence, cryptic phylogeographic lineages may fade away or become reproductively isolated species simply depending on the time they persist in allopatry, and without definite ecomorphological divergence.
T2  - Molecular Ecology
T1  - Phylogeography of a cryptic speciation continuum in Eurasian spadefoot toads (Pelobates).
DO  - 10.1111/mec.15133
ER  - 

@article{
author = "Dufresnes, Christophe and Strachinis, Ilias and Suriadna, Nataliia and Mykytynets, Galyna and Cogălniceanu, Dan and Székely, Paul and Vukov, Tanja and Arntzen, Jan W. and Wielstra, Ben and Lymberakis, Petros and Geffen, Eli and Gafny, Sarig and Kumlutaş, Yusuf and Ilgaz, Çetin and Candan, Kamil and Mizsei, Edvárd and Szabolcs, Márton and Kolenda, Krzysztof and Smirnov, Nazar and Géniez, Philippe and Lukanov, Simeon and Crochet, Pierre-André and Dubey, Sylvain and Perrin, Nicolas and Litvinchuk, Spartak N. and Denoël, Mathieu",
year = "2019",
abstract = "Cryptic phylogeographic diversifications provide unique models to examine the role of phylogenetic divergence on the evolution of reproductive isolation, without extrinsic factors such as ecological and behavioural differentiation. Yet, to date very few comparative studies have been attempted within such radiations. Here, we characterize a new speciation continuum in a group of widespread Eurasian amphibians, the Pelobates spadefoot toads, by conducting multilocus (restriction site associated DNA sequencing and mitochondrial DNA) phylogenetic, phylogeographic and hybrid zone analyses. Within the P. syriacus complex, we discovered species-level cryptic divergences (>5 million years ago [My]) between populations distributed in the Near-East (hereafter P. syriacus sensu stricto [s.s.]) and southeastern Europe (hereafter P. balcanicus), each featuring deep intraspecific lineages. Altogether, we could scale hybridizability to divergence time along six different stages, spanning from sympatry without gene flow (P. fuscus and P. balcanicus, >10 My), parapatry with highly restricted hybridization (P. balcanicus and P. syriacus s.s., >5 My), narrow hybrid zones (~15 km) consistent with partial reproductive isolation (P. fuscus and P. vespertinus, ~3 My), to extensive admixture between Pleistocene and refugial lineages (≤2 My). This full spectrum empirically supports a gradual build up of reproductive barriers through time, reversible up until a threshold that we estimate at ~3 My. Hence, cryptic phylogeographic lineages may fade away or become reproductively isolated species simply depending on the time they persist in allopatry, and without definite ecomorphological divergence.",
journal = "Molecular Ecology",
title = "Phylogeography of a cryptic speciation continuum in Eurasian spadefoot toads (Pelobates).",
doi = "10.1111/mec.15133"
}

Dufresnes, C., Strachinis, I., Suriadna, N., Mykytynets, G., Cogălniceanu, D., Székely, P., Vukov, T., Arntzen, J. W., Wielstra, B., Lymberakis, P., Geffen, E., Gafny, S., Kumlutaş, Y., Ilgaz, Ç., Candan, K., Mizsei, E., Szabolcs, M., Kolenda, K., Smirnov, N., Géniez, P., Lukanov, S., Crochet, P., Dubey, S., Perrin, N., Litvinchuk, S. N.,& Denoël, M.. (2019). Phylogeography of a cryptic speciation continuum in Eurasian spadefoot toads (Pelobates).. in Molecular Ecology.
https://doi.org/10.1111/mec.15133

Dufresnes C, Strachinis I, Suriadna N, Mykytynets G, Cogălniceanu D, Székely P, Vukov T, Arntzen JW, Wielstra B, Lymberakis P, Geffen E, Gafny S, Kumlutaş Y, Ilgaz Ç, Candan K, Mizsei E, Szabolcs M, Kolenda K, Smirnov N, Géniez P, Lukanov S, Crochet P, Dubey S, Perrin N, Litvinchuk SN, Denoël M. Phylogeography of a cryptic speciation continuum in Eurasian spadefoot toads (Pelobates).. in Molecular Ecology. 2019;.
doi:10.1111/mec.15133 .

Dufresnes, Christophe, Strachinis, Ilias, Suriadna, Nataliia, Mykytynets, Galyna, Cogălniceanu, Dan, Székely, Paul, Vukov, Tanja, Arntzen, Jan W., Wielstra, Ben, Lymberakis, Petros, Geffen, Eli, Gafny, Sarig, Kumlutaş, Yusuf, Ilgaz, Çetin, Candan, Kamil, Mizsei, Edvárd, Szabolcs, Márton, Kolenda, Krzysztof, Smirnov, Nazar, Géniez, Philippe, Lukanov, Simeon, Crochet, Pierre-André, Dubey, Sylvain, Perrin, Nicolas, Litvinchuk, Spartak N., Denoël, Mathieu, "Phylogeography of a cryptic speciation continuum in Eurasian spadefoot toads (Pelobates)." in Molecular Ecology (2019),
https://doi.org/10.1111/mec.15133 . .

TY  - JOUR
AU  - Ajduković, Maja
AU  - Galis, Frietson
AU  - Arntzen, Jan W.
AU  - Ivanovic, Ana
PY  - 2015
UR  - https://radar.ibiss.bg.ac.rs/handle/123456789/2337
AB  - We explored intraspecific variation in vertebral formulae, more
   specifically the variation in the number of thoracic vertebrae and
   frequencies of transitional sacral vertebrae in Triturus newts (Caudata:
   Salamandridae). Within salamandrid salamanders this monophyletic group
   shows the highest disparity in the number of thoracic vertebrae and
   considerable intraspecific variation in the number of thoracic
   vertebrae. Triturus species also differ in their ecological preferences,
   from predominantly terrestrial to largely aquatic. Following Geoffroy
   St. Hilaire's and Darwin's rule which states that structures with a
   large number of serially homologous repetitive elements are more
   variable than structures with smaller numbers, we hypothesized that the
   variation in vertebral formulae increases in more elongated species with
   a larger number of thoracic vertebrae. We furthermore hypothesized that
   the frequency of transitional vertebrae will be correlated with the
   variation in the number of thoracic vertebrae within the species. We
   also investigated potential effects of species hybridization on the
   vertebral formula. The proportion of individuals with a number of
   thoracic vertebrae different from the modal number and the range of
   variation in number of vertebrae significantly increased in species with
   a larger number of thoracic vertebrae. Contrary to our expectation, the
   frequencies of transitional vertebrae were not correlated with
   frequencies of change in the complete vertebrae number. The frequency of
   transitional sacral vertebra in hybrids did not significantly differ
   from that of the parental species. Such a pattern could be a result of
   selection pressure against transitional vertebrae and/or a bias towards
   the development of full vertebrae numbers. Although our data indicate
   relaxed selection for vertebral count changes in more elongated, aquatic
   species, more data on different selective pressures in species with
   different numbers of vertebrae in the two contrasting, terrestrial and
   aquatic environments are needed to test for causality.
T2  - Peerj
T1  - Homeotic transformations and number changes in the vertebral column of
 Triturus newts
IS  - e1397
VL  - 3
DO  - 10.7717/peerj.1397
ER  - 

@article{
author = "Ajduković, Maja and Galis, Frietson and Arntzen, Jan W. and Ivanovic, Ana",
year = "2015",
abstract = "We explored intraspecific variation in vertebral formulae, more
   specifically the variation in the number of thoracic vertebrae and
   frequencies of transitional sacral vertebrae in Triturus newts (Caudata:
   Salamandridae). Within salamandrid salamanders this monophyletic group
   shows the highest disparity in the number of thoracic vertebrae and
   considerable intraspecific variation in the number of thoracic
   vertebrae. Triturus species also differ in their ecological preferences,
   from predominantly terrestrial to largely aquatic. Following Geoffroy
   St. Hilaire's and Darwin's rule which states that structures with a
   large number of serially homologous repetitive elements are more
   variable than structures with smaller numbers, we hypothesized that the
   variation in vertebral formulae increases in more elongated species with
   a larger number of thoracic vertebrae. We furthermore hypothesized that
   the frequency of transitional vertebrae will be correlated with the
   variation in the number of thoracic vertebrae within the species. We
   also investigated potential effects of species hybridization on the
   vertebral formula. The proportion of individuals with a number of
   thoracic vertebrae different from the modal number and the range of
   variation in number of vertebrae significantly increased in species with
   a larger number of thoracic vertebrae. Contrary to our expectation, the
   frequencies of transitional vertebrae were not correlated with
   frequencies of change in the complete vertebrae number. The frequency of
   transitional sacral vertebra in hybrids did not significantly differ
   from that of the parental species. Such a pattern could be a result of
   selection pressure against transitional vertebrae and/or a bias towards
   the development of full vertebrae numbers. Although our data indicate
   relaxed selection for vertebral count changes in more elongated, aquatic
   species, more data on different selective pressures in species with
   different numbers of vertebrae in the two contrasting, terrestrial and
   aquatic environments are needed to test for causality.",
journal = "Peerj",
title = "Homeotic transformations and number changes in the vertebral column of
 Triturus newts",
number = "e1397",
volume = "3",
doi = "10.7717/peerj.1397"
}

Ajduković, M., Galis, F., Arntzen, J. W.,& Ivanovic, A.. (2015). Homeotic transformations and number changes in the vertebral column of
 Triturus newts. in Peerj, 3(e1397).
https://doi.org/10.7717/peerj.1397

Ajduković M, Galis F, Arntzen JW, Ivanovic A. Homeotic transformations and number changes in the vertebral column of
 Triturus newts. in Peerj. 2015;3(e1397).
doi:10.7717/peerj.1397 .

Ajduković, Maja, Galis, Frietson, Arntzen, Jan W., Ivanovic, Ana, "Homeotic transformations and number changes in the vertebral column of
 Triturus newts" in Peerj, 3, no. e1397 (2015),
https://doi.org/10.7717/peerj.1397 . .