[Herpetology • 2025] Natural repeated backcrosses lead to triploidy and tetraploidy in parthenogenetic Butterfly Lizards (Leiolepis: Agamidae)

The reconstructed hybridisation events led to the emergence of triploid L. guentherpetersi and its tetraploid hybrid. Distribution map of L. reevesii, L. guttata and L. guentherpetersi ...
Photo of the putative hybrid male N34_H (ZMMU R-17884) in situ. 

in Galoyan, Nazarov, Altmanová, Matveevsky, Kropachev, Dedukh, Iryshkov, Pankin, Sopilko, Nikolaev, Orlov, Arakelyan, Klíma, Solovyeva, Nguyen et Kratochvíl, 2025. 

DOI: doi.org/10.1038/s41598-024-83300-y

Abstract

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.

Keywords: Hybridisation, Leiolepis, Parthenogenesis, Tetraploidy, Meiosis, Vietnam, 

Photo of the putative hybrid male N34_H (ZMMU R-17884) in situ.

The reconstructed hybridisation events led to the emergence of triploid L. guentherpetersi and its tetraploid hybrid.

Distribution map of L. reevesii, L. guttata and L. guentherpetersi is modified after Grismer et al. 2014. The map of Vietnam from data.humdata.org/dataset/cod-ab-vnm edited using QGIS 3.32 Software. Figures represent specific coloration of each species according to sex.

 Eduard Galoyan, Roman Nazarov, Marie Altmanová, Sergey Matveevsky, Ivan Kropachev, Dmitrij Dedukh, Eugene Iryshkov, Mark Pankin, Natalia Sopilko, Oleg Nikolaev, Nikolai Orlov, Marine Arakelyan, Jiří Klíma, Evgeniya Solovyeva, Tao Nguyen and Lukáš Kratochvíl. 2025. Natural repeated backcrosses lead to triploidy and tetraploidy in parthenogenetic butterfly lizards (Leiolepis: Agamidae). Scientific Reports. 15: 3094. DOI: doi.org/10.1038/s41598-024-83300-y [24 January 2025]

 

[Herpetology • 2022] A Molecular-genetics Perspective on the Systematics of the Parthenogenetic Flowerpot Blindsnake Indotyphlops braminus (Daudin, 1803) (Serpentes: Typhlopidae)

Flowerpot Blindsnake Indotyphlops braminus (Daudin, 1803) 

 in Wickramasinghe, Wickramasinghe, Vidanapathirana, ... & Gower, 2022. 

 DOI: 10.1080/14772000.2022.2062478 

   facebook.com/NethuWickramasinghe 

Researchgate.net/publication/361237554

 

Abstract

Sri Lanka has a rich snake diversity, but the island’s scolecophidians (‘blindsnakes’) are poorly understood due to the cryptic, burrowing habits of these inconspicuous animals and lack of systematic field surveys and morphological and molecular analyses. Here we report findings from a systematic survey carried out over a decade across the island of Sri Lanka, focusing particularly on the globally widespread, parthenogenetic species Indotyphlops braminus. We report 780 locations across the island in which this species was recorded, at elevations of 1–1,424 m asl, and mostly <1,000 m (771 out of 780 localities). We provide a molecular-systematics perspective by reporting new DNA sequence data for 15 specimens from Sri Lanka, and new analyses of asiatyphlopine molecular genetic diversity and relationships. Based on molecular results, we conclude that (i) Indotyphlops, as originally conceived may not be monophyletic, (ii) phenotypically the I. braminus-like blindsnakes widespread across most of Sri Lanka are a single, genetically homogeneous species, and (iii) some populations from peninsular India are very similar in DNA sequence to I. braminus from Sri Lanka, but others are genetically highly distinct and unlikely to be conspecific. Based on the estimated phylogenetic relationships, we recommend that I. braminus is currently best recognized as a phenotypically exceptional species of Indotyphlops rather than, as recently proposed, the only species of a monotypic genus (Virgotyphlops).

Key words: Asia, Typhlopinae, distribution, diversity, phylogenetics, snake, Sri Lanka, Typhlopidae

  Photographs and drawings of example specimens of Indotyphlops braminus found in Sri Lanka during the reported study.
(A) Dorsal view of specimen MW18_102D in life. (B) Ventral aspect in life of MW18_102D. (C) Dorsal view in life of MW18_028D.
(D) Dorsal aspect of head of MW18_102D, showing disposition of head glands. (E) Ventral aspect of head of MW18_102D, showing characteristically pale chin of I. braminus. (F) Dorsolateral aspect of head of MW18_102D.
(G) Line drawing of MW18_102D showing head scalation. (H) Close up view of vent and tail of MW18_102D. (I) Line drawing of MW18_102D showing the scales close to vent, anal scale is denoted with an asterisk and preanals abbreviated as PA. Scale bars in parts G and I = 1 mm.

 

Nethu Wickramasinghe, L. J. Mendis Wickramasinghe, Dulan Ranga Vidanapathirana, Kamani H. Tennakoon, Sameera R. Samarakoon and David J. Gower. 2022. A Molecular-genetics Perspective on the Systematics of the Parthenogenetic Flowerpot Blindsnake Indotyphlops braminus (Daudin, 1803) (Squamata: Serpentes: Typhlopidae). Systematics and Biodiversity. 20(1);  DOI: 10.1080/14772000.2022.2062478  

  facebook.com/NethuWickramasinghe/posts/10166480892150174

Researchgate.net/publication/361237554_systematics_of_Indotyphlops_braminus

[Crustacea • 2017] Procambarus virginalis • The Marbled Crayfish (Decapoda: Cambaridae) represents An Independent New Species

Procambarus virginalis  Lyko, 2017

 DOI: 10.11646/zootaxa.4363.4.6 

Abstract

Marbled crayfish are a globally expanding population of parthenogenetically reproducing freshwater decapods. They are closely related to the sexually reproducing slough crayfish, Procambarus fallax, which is native to the southeastern United States. Previous studies have shown that marbled crayfish are morphologically very similar to P. fallax. However, different fitness traits, reproductive incompatibility and substantial genetic differences suggest that the marbled crayfish should be considered an independent species. This article provides its formal description and scientific name, Procambarus virginalis sp. nov.

Keywords: Crustacea, parthenogenesis, annulus ventralis, genetic analysis, mitochondrial DNA

FIGURE 2. Procambarus virginalis new species holotype, dorsal views.  

Procambarus virginalis sp. nov.

Diagnosis. Body pigmented, eyes well developed. Rostrum with marginal spine and lacking median carina. Carapace with cervical spine. Areola 5 to 7 times as long as wide, constituting 30 to 35 percent carapace length (Tab. 1). Suborbital angle obtuse and weak. Postorbital ridge well developed with cephalic spine. Hepatic area punctate. Antennal scale approximately 2.5 times as long as wide, widest at midlength. Annulus ventralis bellshaped, about 1.6 times as broad as long, bisected by narrow furrow leading caudally into median depression. Sinus originating on median line, continuing longitudinally on anterior half, then curving dextrally before curving caudally before continuing and terminating on median line. Sternum immediately cephalic to annulus with no tubercles or projections and not overhanging annulus. Unadorned bell-shaped postannular sclerite with central longitudinal furrow, width similar to annulus. First pleopods present. Mitochondrial DNA with guanine and cytosine at positions 8754 and 8783, respectively (GenBank accession number KT074364, see Tab. 2 for a list of discriminatory genetic variants).

Etymology. The name Procambarus virginalis is derived from the preliminary designation Procambarus fallax forma virginalis (Martin et al., 2010) and reflects the species' unique parthenogenetic mode of reproduction. 

Remarks. The oldest known record of P. virginalis is from a German biologist and hobby aquarist. In a personal conversation with the author (February 2017), he recalled obtaining an uncharacterized batch of "Texas crayfish" from a pet trader specializing in American insects and other invertebrates, at a trade fair in Frankfurt (Germany) in 1995. Animal numbers of this original stock increased rapidly and animals were subsequently distributed to other German aquarists, eventually reaching commercial traders and pet stores. The absence of male animals and the parthenogenetic mode of reproduction were soon recognized among aquarists and subsequently confirmed in the first scientific description of marbled crayfish (Scholtz et al., 2003).

Frank Lyko. 2017. The Marbled Crayfish (Decapoda: Cambaridae) represents An Independent New Species. Zootaxa. 4363(4); 544–552. DOI: 10.11646/zootaxa.4363.4.6

[Herpetology • 2016] Liolaemus parthenos • The First Parthenogenetic Pleurodont Iguanian: A New All-female Liolaemus (Squamata: Liolaemidae) from Western Argentina

Liolaemus parthenos 

 Abdala, Baldo, Juárez & Espinoza. 2016  

  DOI:  10.1643/CH-15-381  

Vertebrate taxa with entirely unisexual populations are composed of females that reproduce without fertilization and are generally of hybrid origin. At least 23 vertebrate families have unisexual lineages. Within squamate reptiles, >40 uniparental species have been described from five major lineages: acrodont iguanians, Gekkota, Serpentes, Scincomorpha, and Varanidae. Pleurodont iguanians include >1100 species, all of which have gonochoristic reproduction. Here we report the discovery of a new unisexual lizard from the liolaemid genus Liolaemus, a species-rich (∼260 species) clade distributed over most of southern South American. The new species, Liolaemus parthenos, is the only known all-female triploid pleurodont iguanian. The structural chromosome heteromorphisms of the karyotypes support the hypothesis that L. parthenos is the product of a hybrid origin. Based on morphology, the new species is assignable to the L. boulengeri group (sensu Abdala, 2007), and phylogenetic analyses of mitochondrial DNA indicate that L. parthenos is nested within L. darwinii, suggesting that the latter is the maternal ancestor of this species. Additional data are needed to identify the patrilineal ancestor.

Cristián S. Abdala, Diego Baldo, Ricardo A. Juárez and Robert E. Espinoza. 2016. The First Parthenogenetic Pleurodont Iguanian: A New All-female Liolaemus (Squamata: Liolaemidae) from Western Argentina. Copeia. 104(2):487-497. DOI:  10.1643/CH-15-381

ResearchGate.net/publication/303905850_The_First_Parthenogenetic_Pleurodont_Iguanian_A_New_All-female_Liolaemus_Squamata_Liolaemidae_from_Western_Argentina

Los taxones de vertebrados con poblaciones totalmente unisexuales se componen de hembras que se reproducen sin fecundación y son generalmente de origen híbrido. Al menos 23 familias de vertebrados tienen linajes unisexuales. Dentro de los reptiles escamosos, se han descrito >40 especies uniparentales pertenecientes a cinco grandes linajes: iguanios acrodontes, Gekkota, Serpentes, Scincomorpha y Varanidae. Los iguanios pleurodontes incluyen >1100 especies, las cuales todas tienen reproducción gonocórica. Aquí presentamos el descubrimiento de un nuevo lagarto unisexual del género Liolaemus, clado con gran riqueza especifica (∼260 especies) distribuido en casi todo el sur de América del Sur. La nueva especie, Liolaemus parthenos, es la única conocida con hembras triploides entre los iguanios pleurodontes. Los heteromorfismos cromosómicos estructurales de sus cariotipos apoyan la hipótesis de que L. parthenos es producto de un origen híbrido. Basado en la morfología, la nueva especie es asignable al grupo de L. boulengeri (sensu Abdala, 2007) y el análisis filogenético de ADN mitocondrial indica que L. parthenos está anidada dentro de L. darwinii, lo que sugiere que este último es el antepasado matrilineal de esta especie. Se necesitan más datos para identificar su antepasado patrilineal.