Obligatory parthenogenesis in vertebrates is restricted to squamate reptiles and evolved through hybridisation. Parthenogens can hybridise with sexual species, resulting in individuals with increased ploidy levels. We describe two successive hybridisations of the parthenogenetic butterfly lizards (genus Leiolepis) in Vietnam with a parental sexual species. Contrary to previous proposals, we document that parthenogenetic L. guentherpetersi has mitochondrial DNA and two haploid sets from L. guttata and one from L. reevesii, suggesting that it is the result of a backcross of a parthenogenetic L. guttata × L. reevesii hybrid with a L. guttata male increasing ploidy from 2n to 3n. Within the range of L. guentherpetersi, we found an adult tetraploid male with three L. guttata and one L. reevesii haploid genomes. It probably originated from fertilisation of an unreduced triploid L. guentherpetersi egg by a L. guttata sperm. Although its external morphology resembles that of the maternal species, it possessed exceptionally large erythrocytes and was likely sterile. As increased ploidy level above triploidy or tetraploidy appears to be harmful for amniotes, all-female asexual lineages should evolve a strategy to prevent incorporation of other haploid genomes from a sexual species by avoiding fertilisation by sexual males.

Department of Ecology Faculty of Science Charles University Viničná 7 Prague 128 44 Czech Republic

Department of Zoology Biological Faculty of Yerevan State University Charents st 8 Yerevan Armenia

Laboratory of Cell Regeneration and Plasticity Institute of Animal Physiology and Genetics Czech Academy of Sciences Rumburská 89 277 21 Liběchov Czech Republic

Laboratory of Fish Genetics Institute of Animal Physiology and Genetics Czech Academy of Sciences Rumburská 89 277 21 Liběchov Czech Republic

Laboratory of Non Mendelian Evolution Institute of Animal Physiology and Genetics Czech Academy of Sciences Rumburská 89 277 21 Liběchov Czech Republic

Lomonosov Moscow State University Kolmogorova st 1 Moscow Russia

Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences Leninsky Prospect 33 Moscow Russia

Vavilov Institute of General Genetics of the Russian Academy of Sciences Gubkin St 3 Moscow Russia

Vietnam Academy of Science and Technology Hanoi Vietnam

Zoological Institute Russian Academy of Sciences Universitetskaya nab 1 St Petersburg 199034 Russia

Zoological Museum of Moscow State University B Nikitskaya ul 2 Moscow 125009 Russia

Zobrazit více v PubMed

Kearney, M., Fujita, M. K. & Ridenour, J. Lost sex in reptiles: Constraints and correlations. In Lost Sex: The Evolutionary Biology of Parthenogenesis (eds Schön, I. et al.) 447–474 (Springer Scientific, 2009). 10.1007/978-90-481-2770-2_21.

Fyon, F., Berbel-Filho, W. M., Schlupp, I., Wild, G. & Úbeda, F. Why do hybrids turn down sex? Evolution77, 2186–2199. 10.1093/evolut/qpad129 (2023). PubMed

Sinclair, E. A., Pramuk, J. B., Bezy, R. L., Crandall, K. A. & Sites, J. W. Jr. DNA evidence for nonhybrid origins of parthenogenesis in natural populations of vertebrates. Evolution64, 1346–1357. 10.1111/j.1558-5646.2009.00893.x (2010). PubMed

Shimizu, Y., Shibata, N., Sakaizumi, M. & Yamashita, M. Production of diploid eggs through premeiotic endomitosis in the hybrid medaka between Oryzias latipes and O. curvinotus. Zool. Sci.17, 951–958. 10.2108/zsj.17.951 (2000).

Marta, A. et al. Genetic and karyotype divergence between parents affect clonality and sterility in hybrids. eLife12, RP88366. 10.7554/eLife.88366.3 (2023). PubMed PMC

Wright, J. W. & Lowe, C. H. Weeds, polyploids, parthenogenesis, and the geographical and ecological distribution of all-female species of Cnemidophorus. Copeia1968, 128–138. 10.2307/1441559 (1968).

Billy, A. J. Why do parthenogenetic lizards hybridize with sympatric bisexual relatives? Evol. Theory9, 225–238 (1990).

Paulissen, M. A., Walker, J. M. & Cordes, J. E. Status of the parthenogenetic lizards of the Cnemidophorus laredoensis complex in Texas: Re-survey after eleven years. Tex. J. Sci.53, 121–138 (2001).

Petrosyan, V. G. et al. New records and geographic distribution of the sympatric zones of unisexual and bisexual rock lizards of the genus Darevskia in Armenia and adjacent territories. Biodivers. Data J.8, e56030. 10.3897/BDJ.8.e56030 (2020). PubMed PMC

Tarkhnishvili, D., Gavashelishvili, A., Avaliani, A., Murtskhvaladze, M. & Mumladze, L. Unisexual rock lizard might be outcompeting its bisexual progenitors in the Caucasus. Biol. J. Linn. Soc.101, 447–460. 10.1111/j.1095-8312.2010.01498.x (2010).

Darevsky, I. S., Kupriyanova, L. A. & Uzzell, T. Parthenogenesis in reptiles. In Evolution and Ecology of Unisexual Vertebrates (eds Dawley, R. M. & Bogart, J. P.) (The New York State Museum, Albany, 1985).

Danielyan, F., Arakelyan, M. & Stepanyan, I. Hybrids of Darevskia valentini, D. armeniaca and D. unisexualis from a sympatric population in Armenia. Amphib. -Reptil29, 487–504. 10.1163/156853808786230424 (2008).

Dawley, R. M. & Bogart, J. P. Evolution and ecology of unisexual vertebrates. N. Y. State Mus. Bull.466, 1–302 (1989).

Lamatsch, D. K. & Stöck, M. Sperm-dependent parthenogenesis and hybridogenesis in teleost fishes. In Lost Sex: The Evolutionary Biology of Parthenogenesis (eds Schön, I. et al.) 399–432 (Springer Scientific, 2009). 10.1007/978-90-481-2770-2_19.

Stöck, M. et al. A brief review of vertebrate sex evolution with a pledge for integrative research: Towards ‘sexomics’. Philos. Trans. R Soc. Lond. B Biol. Sci.376, 20200426. 10.1098/rstb.2020.0426 (2021). PubMed PMC

Dedukh, D. et al. A cyclical switch of gametogenic pathways in hybrids depends on the ploidy level. Commun. Biol.7, 424. 10.1038/s42003-024-05948-6 (2024). PubMed PMC

Lampert, K. P. Facultative parthenogenesis in vertebrates: Reproductive error or chance? Sex. Dev.2, 290–301. 10.1159/000195678 (2009). PubMed

Moritz, C. The origin and evolution of parthenogenesis in Heteronotia binoei (Gekkonidae). Chromosoma89, 151–162. 10.1007/BF00292899 (1984).

Kluge, A. G. Hemidactylus garnotii Duméril and Bibron, a triploid all-female species of gekkonid lizard. Copeia1969, 651–664. 10.2307/1441789 (1969).

Adams, M., Foster, R., Hutchinson, M. N., Hutchinson, R. G. & Donnellan, S. C. The Australian scincid lizard Menetia greyii: A new instance of widespread vertebrate parthenogenesis. Evolution57, 2619–2627. 10.1111/j.0014-3820.2003.tb01504.x (2003). PubMed

Lowe, C. H. & Wright, J. W. Evolution of parthenogenetic species of Cnemidophorus (whiptail lizards) in western North America. J. Ariz Acad. Sci.4, 81–87 (1966).

Cole, C. J., Dessauer, H. C. & Barrowclough, G. F. Hybrid origin of a unisexual species of whiptail lizard, Cnemidophorus neomexicanus, in western North America: New evidence and a review. Am. Mus. Nov.2905, 1–38 (1988).

Avila, L. J. & Martori, R. A. A unisexual species of Teius Merrem 1820 (Sauria Teiidae) from central Argentina. Trop. Zool.4, 193–201. 10.1080/03946975.1991.10539489 (1991).

Cole, C. J., Dessauer, H. C. & Markezich, A. L. Missing link found: The second ancestor of Gymnophthalmus underwoodi (Squamata: Teiidae), a South American unisexual lizard of hybrid origin. Am. Mus. Nov.3055, 1–13 (1993).

Kizirian, D. A. & Cole, C. J. Origin of the unisexual lizard Gymnophthalmus underwoodi (Gymnophthalmidae) inferred from mitochondrial DNA nucleotide sequences. Mol. Phylogenet. Evol.11, 394–400. 10.1006/mpev.1998.0591 (1999). PubMed

Darevsky, I. S. Rock Lizards of the Caucasus (Smithsonian Institution and the National Science Foundation, Washington, 1978).

Abdala, C. S., Baldo, D., Juárez, R. A. & Espinoza, R. E. The first parthenogenetic pleurodont iguanian: A new all-female Liolaemus (Squamata: Liolaemidae) from Western Argentina. Copeia104, 487–497. 10.1643/CH-15-381 (2016).

Darevsky, I. S. & Kupriyanova, L. A. Two new all-female lizard species of the genus Leiolepis Cuvier, 1829 from Thailand and Vietnam (Squamata: Sauria: Uromastycinae). Herpetozoa6, 3–20 (1993).

Nussbaum, R. The Brahminy blind snake (Ramphotyphlops braminus) in the Seychelles archipelago: Distribution, variation, and further evidence for parthenogenesis. Herpetologica36, 215–221 (1980).

Moritz, C. & Bi, K. Spontaneous speciation by ploidy elevation: Laboratory synthesis of a new clonal vertebrate. Proc. Natl. Acad. Sci. U S A108, 9733–9734. 10.1073/pnas.1106455108 (2011). PubMed PMC

Galoyan, E. A. et al. Love bites: Males of lizards prefer to mate with conspecifics, but do not disdain parthenogens. Biol. J. Linn. Soc.10.1093/biolinnean/blae057 (2024) (in Press).

Darevsky, I. S. & Danielyan, F. D. Diploid and triploid progeny arising from natural mating of parthenogenetic Lacerta armeniaca and L. unisexualis with bisexual L. saxicola valentini. J. Herpetol.2, 65–69. 10.2307/1563104 (1968).

Grismer, J. L. et al. Multiple origins of parthenogenesis, and a revised species phylogeny for the Southeast Asian butterfly lizards, Leiolepis. Biol. J. Linn. Soc.113, 1080–1093. 10.1111/bij.12367 (2014).

Trifonov, V. A. et al. Comparative chromosome painting and NOR distribution suggest a complex hybrid origin of triploid Lepidodactylus lugubris (Gekkonidae). PLoS ONE10, e0132380. 10.1371/journal.pone.0132380 (2015). PubMed PMC

Barley, A. J., Nieto-Montes de Oca, A., Manríquez-Morán, N. L. & Thomson, R. C. The evolutionary network of whiptail lizards reveals predictable outcomes of hybridization. Science377, 773–777. 10.1126/science.abn1593 (2022). PubMed

Neaves, W. B. Tetraploidy in a hybrid lizard of the genus Cnemidophorus (Teiidae). Breviora381, 1–25 (1971).

Lutes, A. A., Baumann, D. P., Neaves, W. B. & Baumann, P. Laboratory synthesis of an independently reproducing vertebrate species. Proc. Natl. Acad. Sci. USA108, 9910–9915. 10.1073/pnas.1102811108 (2011). PubMed PMC

Cole, C. J. et al. The second known tetraploid species of parthenogenetic tetrapod (Reptilia: Squamata: Teiidae): Description, reproduction, comparisons with ancestral taxa, and origins of multiple clones. Bull. Mus. Comp. Zool.161, 285–321. 10.3099/MCZ37.1 (2017).

Cole, C. J., Taylor, H. L., Baumann, D. P. & Baumann, P. Neaves’ whiptail lizard: The first known tetraploid parthenogenetic tetrapod (Reptilia: Squamata: Teiidae). Breviora539, 1–20. 10.3099/MCZ17.1 (2014).

Maciak, S. et al. Standard Metabolic Rate (SMR) is inversely related to erythrocyte and genome size in allopolyploid fish of the Cobitis taenia hybrid complex. Funct. Ecol.25, 1072–1078. 10.1111/j.1365-2435.2011.01870.x (2011).

Cadart, C., Bartz, J., Oaks, G., Liu, M. Z. & Heald, R. Polyploidy in Xenopus lowers metabolic rate by decreasing total cell surface area. Curr. Biol.33, 1744-1752e7. 10.1016/j.cub.2023.03.071 (2023). PubMed PMC

Tarkhnishvili, D. & Iankoshvili, G. The farther, the closer: Geographic proximity and niche overlap versus genetic divergence in Caucasian rock lizards. Biol. J. Linn. Soc.140, 41–57. 10.1093/biolinnean/blad034 (2023).

Galoyan, E. A., Tsellarius, E. Y. & Arakelyan, M. S. Friend-or-foe? Behavioural evidence suggests interspecific discrimination leading to low probability of hybridization in two coexisting rock lizard species (Lacertidae, Darevskia). Behav. Ecol. Sociobiol.73, 46. 10.1007/s00265-019-2650-7 (2019).

Cuellar, O. Reproduction and the mechanism of meiotic restitution in the parthenogenetic lizard Cnemidophorus uniparens. J. Morphol.133, 139–165 (1971). PubMed

Case, T. J. Patterns of coexistence in sexual and asexual species of Cnemidophorus lizards. Oecologia83, 220–227 (1990). PubMed

Paulissen, M. A., Walker, J. M. & Cordes, J. E. Can parthenogenetic Cnemidophorus laredoensis (Teiidae) coexist with its bisexual congeners? J. Herpetol.26, 153–158. 10.2307/1564856 (1992).

Cacciali, P., Morando, M., Köhler, G. & Avila, L. On the distribution of the genus Teius Merrem, 1820 (Reptilia: Squamata: Teiidae). Zootaxa4136, 491–514. 10.11646/zootaxa.4136.3.4 (2016). PubMed

Hall, W. P. Three probable cases of parthenogenesis in lizards (Agamidae, Chameleonidae, Gekkonidae). Experientia26, 1271–1273. 10.1007/BF01898012 (1970). PubMed

Grismer, J. L. & Grismer, L. L. Who’s your mommy? Identifying maternal ancestors of unisexual species of Leiolepis Cuvier, 1829 and the description of a new endemic species of unisexual Leiolepis Cuvier, 1829 from southern Vietnam. Zootaxa2433, 47–61. 10.11646/zootaxa.2433.1.3 (2010).

Uetz, P. et al. The Reptile Database (2024). http://www.reptile-database.org, accessed October 28.

de Queiroz, A., Lawson, R. & Lemos-Espinal, J. A. Phylogenetic relationships of North American garter snakes (Thamnophis) based on four mitochondrial genes: How much DNA sequence is enough? Mol. Phylogenet. Evol.22, 315–329. 10.1006/mpev.2001.1074 (2002). PubMed

Burbrink, F. T., Lawson, R. & Slowinski, J. B. Mitochondrial DNA phylogeography of the polytypic North American rat snake (Elaphe obsoleta): A critique of the subspecies concept. Evolution54, 2107–2118. https://doi.org/10.1554/0014-3820(2000)054[2107:MDPOTP]2.0.CO;2 (2000). PubMed

Lin, L. H., Ji, X., Diong, C. H., Du, Y. & Lin, C. X. Phylogeography and population structure of the Reevese’s butterfly lizard (Leiolepis reevesii) inferred from mitochondrial DNA sequences. Mol. Phylogenet. Evol.56, 601–607. 10.1016/j.ympev.2010.04.032 (2010). PubMed

Okonechnikov, K., Golosova, O. & Fursov, M. the UGENE team. Unipro UGENE: A unified bioinformatics toolkit. Bioinformatics28, 1166–1167. 10.1093/bioinformatics/bts091 (2012). PubMed

Okajima, Y. & Kumazawa, Y. Mitochondrial genomes of acrodont lizards: Timing of gene rearrangements and phylogenetic and biogeographic implications. BMC Evol. Biol.10, 1–15. 10.1186/1471-2148-10-141 (2010). PubMed PMC

Nguyen, L. T., Schmidt, H. A., von Haeseler, A. & Minh, B. Q. IQ-TREE: A fast and effective stochastic algorithm for estimating maximum likelihood phylogenies. Mol. Biol. Evol.32, 268–274. 10.1093/molbev/msu300 (2015). PubMed PMC

Minh, B. Q., Nguyen, M. A. T. & von Haeseler, A. Ultrafast approximation for phylogenetic bootstrap. Mol. Biol. Evol.30, 1188–1195. 10.1093/molbev/mst024 (2013). PubMed PMC

Kalyaanamoorthy, S. et al. Fast model selection for accurate phylogenetic estimates. Nat. Methods14, 587–589. 10.1038/nmeth.4285 (2017). PubMed PMC

Lanfear, R., Calcott, B., Ho, S. Y. W. & Guindon, S. PartitionFinder: Combined selection of partitioning schemes and substitution models for phylogenetic analyses. Mol. Biol. Evol.29, 1695–1701. 10.1093/molbev/mss020 (2012). PubMed

Ronquist, F. & Huelsenbeck, J. P. MrBayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics19, 1572–1574. 10.1093/bioinformatics/btg180 (2003). PubMed

Rambaut, A., Drummond, A. J. & Suchard, M. Tracer v1.7.1 (2007). http://beast.bio.ed.ac.uk/Tracer.

Huelsenbeck, J. P. & Ronquist, F. MRBAYES: Bayesian inference of phylogeny. Bioinformatics17, 754–755. 10.1093/bioinformatics/17.8.754 (2001). PubMed

Tamura, K., Stecher, G. & Kumar, S. MEGA11: Molecular evolutionary genetics analysis version 11. Mol. Biol. Evol.38, 3022–3027. 10.1093/molbev/msab120 (2021). PubMed PMC

Meyer, D., Zeileis, A., Hornik, K. & Vcd Visualizing Categorical Data. R Package Version 1.4-4. (2017).

Kassambara, A. Factoextra: extract and visualize the results of multivariate data analyses. R package version 1.0.7. (2020). https://CRAN.R-project.org/package=factoextra

Wickham, H. In Data Analysis in ggplot2: Elegant Graphics for Data Analysis. 189–201 (eds Wickham, H.) (Springer, 2016). 10.1007/978-3-319-24277-4_9

Wright, J. H. A rapid method for the differential staining of blood films and malarial parasites. J. Med. Res.7, 138–144 (1902). PubMed PMC

Kuznetsova, A., Brockhoff, P. B. & Christensen, R. H. B. ImerTest package: Tests in linear mixed effects models. J. Stat. Softw.82, 1–26. 10.18637/jss.v082.i13 (2017).

Lenth, R., Singmann, H., Love, J., Buerkner, P. & Herve, M. Package “Emmeans”. R Package Version 4.0–3. (2018).

Kassambara, A. ggpubr:’ggplot2’based publication ready plots. R package version 2. (2018). http://cran.r-project.org/package=emmeans

Ford, C. E. & Hamerton, J. L. A colchicine, hypotonic citrate, squash sequence for mammalian chromosomes. Stain Technol.31, 247–251. 10.3109/10520295609113814 (1956). PubMed

Altmanová, M. et al. Karyotype stasis but species-specific repetitive DNA patterns in Anguis lizards (Squamata: Anguidae), in the evolutionary framework of Anguiformes. Zool. J. Linn. Soc.202, zlad153. 10.1093/zoolinnean/zlad153 (2024).

Peters, A., Plug, A. W., Van Vugt, M. J. & De Boer, P. A drying-down technique for the spreading of mammalian meiocytes from the male and female germline. Chromosome Res.5, 66–68. 10.1023/a:1018445520117 (1997). PubMed

Anderson, L. K., Reeves, A., Webb, L. M. & Ashley, T. Distribution of crossing over on mouse synaptonemal complexes using immunofluorescent localization of MLH1 protein. Genetics151, 1569–1579. 10.1093/genetics/151.4.1569 (1999). PubMed PMC

Moritz, C. Parthenogenesis in the tropical gekkonid lizard, Nactus arnouxii (Sauria: Gekkonidae). Evolution41, 1252–1266. 10.2307/2409091 (1987). PubMed

Ota, H., Hikida, T. & Lue, K. Y. Polyclony in a triploid gecko, Hemidactylus stejnegeri, from Taiwan, with notes on its bearing on the chromosomal diversity of the H. garnotii-vietnamensis complex (Sauria: Gekkonidae). Genetica79, 183–189. 10.1007/BF00121511 (1989).

Dedukh, D., Altmanová, M., Klíma, J. & Kratochvíl, L. Premeiotic endoreplication is essential for obligate parthenogenesis in geckos. Development149, dev200345. 10.1242/dev.200345 (2022). PubMed

Reeder, T. W., Cole, C. J. & Dessauer, H. C. Phylogenetic relationships of whiptail lizards of the genus Cnemidophorus (Squamata: Teiidae): a test of monophyly, reevaluation of karyotypic evolution, and review of hybrid origins. Am. Mus. Nov.3365, 1–61. https://doi.org/10.1206/0003-0082(2002)365<0001:PROWLO>2.0.CO;2 (2002).

Brunes, T. O., da Silva, A. J., Marques-Souza, S., Rodrigues, M. T. & Pellegrino, K. C. M. Not always young: The first vertebrate ancient origin of true parthenogenesis found in an Amazon leaf litter lizard with evidence of mitochondrial haplotypes surfing on the wave of a range expansion. Mol. Phylogenet. Evol.135, 105–122. 10.1016/j.ympev.2019.01.023 (2019). PubMed

Wynn, A. H., Cole, C. J. & Gardner, A. L. Apparent triploidy in the unisexual Brahminy blind snake, Ramphotyphlops braminus. Am. Mus. Nov.2868, 1–7 (1987).

Schuett, G. W. et al. Production of offspring in the absence of males: Evidence for facultative parthenogenesis in bisexual snakes. Herpetol. Nat. Hist.5, 1–10 (1997).

Ho, D. V. et al. Post-meiotic mechanism of facultative parthenogenesis in gonochoristic whiptail lizard species. eLife7, e97035. 10.7554/eLife.97035 (2024). PubMed PMC

Kratochvíl, L. et al. Mixed-sex offspring produced via cryptic parthenogenesis in a lizard. Mol. Ecol.29, 4118–4127. 10.1111/mec.15617 (2020). PubMed

Lutes, A. A., Neaves, W. B., Baumann, D. P., Wiegraebe, W. & Baumann, P. Sister chromosome pairing maintains heterozygosity in parthenogenetic lizards. Nature464, 283–286. 10.1038/nature08818 (2010). PubMed PMC

Spangenberg, V. et al. Reticulate evolution of the rock lizards: meiotic chromosome dynamics and spermatogenesis in diploid and triploid males of the genus Darevskia. Genes8, 149. 10.3390/genes8060149 (2017). PubMed PMC

Taylor, H. L. et al. Natural hybridization between the teiid lizards Cnemidophorus tesselatus (parthenogenetic) and C. tigris marmoratus (bisexual): Assessment of evolutionary alternatives. Am. Mus. Novit.3345, 1–65. https://doi.org/10.1206/0003-0082(2001)345<0001:NHBTTL>2.0.CO;2 (2001).

L Taylor, H. Comparison of morphological variation among parthenogenetic Aspidoscelis neomexicana, gonochoristic A. sexlineata viridis, and their hybrids (Squamata: Teiidae) from Ute Lake and Conchas Lake, northeastern New Mexico. Southwest. Nat.59, 251–257 (2014).

Manning, G. J., Walker, J. M. & Walker, J. M. Hybridization between normally parthenogenetic Aspidoscelis tesselata and gonochoristic A. sexlineata viridis (Squamata: Teiidae) at Ft. Sumner, De Baca Co., New Mexico. Am. Midl. Nat.155, 411–416 (2006).

Manning, G. J., Cole, C. J., Dessauer, H. C. & Walker, J. M. Hybridization between parthenogenetic lizards (Aspidoscelis neomexicana) and gonochoristic (Aspidoscelis sexlineata viridis) in New Mexico: Ecological, morphological, cytological, and molecular context. Am. Mus. Novit.2005, 1–56. 10.1206/0003-0082(2005)492[0001:HBPLAN]2.0.CO;2 (2005).

Tarkhnishvili, D. et al. Genotypic similarities among the parthenogenetic Darevskia rock lizards with different hybrid origins. BMC Evol. Biol.20, 122. 10.1186/s12862-020-01690-9 (2020). PubMed PMC

Lowe, C. H., Wright, J. W., Cole, C. J. & Bezy, R. L. Natural hybridization between the teiid lizards Cnemidophorus sonorae (parthenogenetic) and Cnemidophorus tigris (bisexual). Syst. Zool.19, 114–127 (1970).

Cole, C. J., Dessauer, H. C., Paulissen, M. A. & Walker, J. M. Hybridization between whiptail lizards in Texas: Aspidoscelis laredoensis and A. gularis, with notes on reproduction of a hybrid. Am. Mus. Nov.3947, 1–13. 10.1206/3947.1 (2020).

Lebeda, I., Ráb, P., Majtánová, Z. & Flajšhans, M. Artificial whole genome duplication in paleopolyploid sturgeons yields highest documented chromosome number in vertebrates. Sci. Rep.10, 19705. 10.1038/s41598-020-76680-4 (2020). PubMed PMC

Gallardo, M., Bickham, J., Honeycutt, R., Ojeda, R. A. & Köhler, N. Discovery of tetraploidy in a mammal. Nature401, 341. 10.1038/43815 (1999). PubMed

Mares, M. A., Braun, J. K., Bárquez, R. M. & Díaz, M. M. Two new genera and species of halophytic desert mammals from isolated salt flats in Argentina. Occas. Pap. Mus. Tex. Tech. Univ.203, 1–27. 10.5962/bhl.title.147045 (2000).

Rovatsos, M. et al. Triploid colubrid snake provides insight into the mechanism of sex determination in advanced snakes. Sex. Dev.12, 251–255. 10.1159/000490124 (2018). PubMed

Iannucci, A. et al. Conserved sex chromosomes and karyotype evolution in monitor lizards (Varanidae). Heredity123, 215–227. 10.1038/s41437-018-0179-6 (2019). PubMed PMC

Pensabene, E., Augstenová, B., Kratochvíl, L. & Rovatsos, M. Differentiated sex chromosomes, karyotype evolution, and spontaneous triploidy in carphodactylid geckos. J. Hered.115, 262–276. 10.1093/jhered/esae010 (2024). PubMed

Bickham, J. W., Tucker, P. K. & Legler, J. M. Diploid-triploid mosaicism: An unusual phenomenon in side-necked turtles (Platemys platycephala). Science227, 1591–1593. 10.1126/science.227.4694.1591 (1985). PubMed

Araya-Donoso, R., Véliz, D., Vidal, M. & Lamborot, M. Relationships of the morphological variation in diploids, triploids and mosaics of Liolaemus chiliensis (Sauria: Liolaemidae). Amphib. -Reptil38, 503–515. 10.1163/15685381-00003132 (2017).

Hardy, L. M. & Cole, C. J. Morphology of a sterile, tetraploid, hybrid whiptail lizard (Squamata, Teiidae, Cnemidophorus). Am. Mus. Nov.3228, 1–16 (1998).

Starostová, Z., Kubička, L., Konarzewski, M., Kozłowski, J. & Kratochvíl, L. Cell size but not genome size affects scaling of metabolic rate in eyelid geckos. Am. Nat.174, E100–E105. 10.1086/603610 (2009). PubMed

Morgan-Richards, M., Langton-Myers, S. S. & Trewick, S. A. Loss and gain of sexual reproduction in the same stick insect. Mol. Ecol.28, 3929–3941. 10.1111/mec.15203 (2019). PubMed PMC

Schwander, T., J Crespi, B., Gries, R. & Gries, G. Neutral and selection-driven decay of sexual traits in asexual stick insects. Proc. Biol. Sci.280, 20130823. 10.1098/rspb.2013.0823 (2013). PubMed PMC

Lodé, T. Have sex or not? Lessons from bacteria. Sex. Dev.6, 325–328. 10.1159/000342879 (2012). PubMed