10(2), 2015, 121 01 September 2014 02 August 2015 Tiana Kohlsdorf 10.2994/SAJH-D-14-00025.1 South American Journal of Herpetology, 10(2), 2015, 121–131 © 2015 Brazilian Society of Herpetology On the Discovery of Bisexual Populations of the Parthenogenetic Lizard Leposoma percarinatum (Gymnophthalmidae), with Insights into the Origin of Parthenogenesis in Leposoma Sergio Marques Souza 1,*, Katia C.M. Pellegrino2, Pedro M. Sales Nunes3, Mauro Teixeira Junior1, Marcelo Gordo4, Vinícius T. de Carvalho5, Alexandre Almeida4, Deyla Paula de Oliveira5, Luciana Frazão4, Tomas Hrbek5, Izeni Pires Farias5, Miguel Trefaut Rodrigues1 1 Universidade de São Paulo, Instituto de Biociências, Departamento de Zoologia. Rua do Matão, Travessa 14, nº 32, Butantã, CEP 05508 ‑090, São Paulo, SP, Brazil. 2 Universidade Federal de São Paulo, Departamento de Ciências Biológicas. Rua Professor Arthur Riedel, 275, Eldorado, CEP 09972 ‑270, Diadema, SP, Brazil. 3 Universidade Federal de Pernambuco, Departamento de Zoologia, Centro de Ciências Biológicas. Avenida Professor Moraes Rego, s/n., Cidade Universitária, CEP 50670‑901, Recife, PE, Brazil. 4 Universidade Federal do Amazonas, Departamento de Biologia. Avenida Rodrigo Otávio, 3.000, Japiim, CEP 69080‑900, Manaus, AM, Brazil. 5 Universidade Federal do Amazonas, Departamento de Genetica, Laboratório de Evolução e Genética Animal. Avenida Rodrigo Otávio, 3.000, Japiim, CEP 69080‑900, Manaus, AM, Brazil. * Corresponding author. Email: [email protected] Abstract. Leposoma percarinatum is one of the two recognized parthenogenetic species in the lizard family Gymnophthalmidae, and only females have been reported to date. Here we report and describe the first known males attributed to the species from two localities of north- western Amazonia. We compare the morphological variation (15 meristic and 10 discrete characters, all relevant to species identification in Leposoma) of males and females from these populations with that of specimens from unisexual populations to test the hypothesis that they belong to the same species. We did not find significant morphological differences between unisexual and bisexual populations, except for those associated with sexual dimorphism. Additionally, we reviewed literature dealing with the origin of parthenogenesis in L. percarinatum and we provide some insights into this subject, in view of the discovery of males in this species. Keywords. Amazonia; Hybridization; Lizards; Unisexuality. Resumo. Leposoma percarinatum é uma das duas espécies de lagartos partenogenéticas da familia Gymnophthalmidae, onde apenas fêmeas são conhecidas até o momento. Neste artigo reportamos e descrevemos os primeiros machos encontrados da espécie, pertencentes a duas populações no noroeste da América do Sul. Com o intuito de testar a hipótese de que os machos encontrados pertencem à espécie L. perca‑ rinatum, comparamos a variação morfológica (15 caracteres merísticos e 10 categóricos, todos relevantes para a identificação de espécies do gênero Leposoma) encontrada em machos e fêmeas das duas populações bissexuais com exemplares de populações unissexuais ao longo da Amazônia. Não encontramos diferenças significativas na morfologia entre populações uni e bissexuais, a não ser aquelas decorrentes de dimorfismo sexual tradicionalmente conhecidas em lagartos. Adicionalmente, revisamos a literatura referente à origem da partenogênese em L. percarinatum e fornecemos algumas reflexões sobre este tópico, fruto do aparecimento de machos na espécie. INTrodUCTioN distributed in 8 families from 67 families of squamate reptiles (Uetz, 2014). The origin of lizard parthenogen- Sex is by far the primary mode of reproduction of esis has been studied in detail in some specific cases (e.g., multicellular organisms, given the evolutionary advan- Heteronotia binoei Gray, 1845: Moritz, 1983; 1993; Aspi‑ tage of genetic recombination (Felsenstein, 1974; May- doscelis Reeder et al., 2002) and, as far as we know, in all nard-Smith, 1978). However, every rule has its excep- but two cases (Lepidophyma flavimaculatum Duméril and tions; hence, the occurrence of parthenogenesis in lizards Duméril, 1851: Sinclair et al., 2010 and Gymnophthalmus (i.e. the development of embryos without fertilization) underwoodi Grant, 1958: Martins, 1991; Yonenaga-Yassu- has long fascinated evolutionary biologists (e.g. Zweifel, da et al., 1995; Benozatti and Rodrigues, 2003), parthe- 1965). Lizards harbor the only truly parthenogenetic ver- nogenesis has a hybrid origin, where two closely related tebrate species known, in which populations of all-female bisexual species reproduce and gave birth to fertile off- individuals reproduce without the involvement of males spring (Kearney et al., 2009; Fujita and Moritz, 2009). (MacCulloch et al., 1997; Kearney et al., 2009). Two instances of parthenogenesis can be found in the en- To date, there are 40 known cases of obligate par- demic Neotropical family Gymnophthalmidae: G. under‑ thenogenetic species in reptiles (Kearney et al., 2009), woodi and Leposoma percarinatum Müller, 1923. The latter Submitted: 01 September 2014 Handling Editor: Tiana Kohlsdorf Accepted: 02 August 2015 doi: 10.2994/SAJH-D-14-00025.1 South American Journal of Herpetology, 10(2), 2015, 121–131 was first proposed to be a unisexual species by Uzzell and After examination of these males, our first main ques- Barry (1971), who noted that all available specimens at- tion was if these specimens could be classified as a new tributed to the species at that time were females. They bisexual species, or if they represent a bisexual population also suggested that L. percarinatum appeared as a result of of L. percarinatum. This question is not as straightforward a hybridization event between L. guianense Ruibal, 1952 as it may seem, because L. percarinatum presents intrigu- and L. parietale Cope, 1885, based mainly on morphologi- ing morphological variation and the taxonomic status of cal evidence. Since then, only females have been recorded L. percarinatum was challenged by the molecular results in the literature and in herpetological collections (Avila- of Pellegrino et al. (2011). As such, to answer this ques- Pires, 1995). tion we performed the following: 1. Quantify the mor- More recently, Pellegrino et al. (2003) analyzed the phological variation found in the unisexual populations karyotypes of three females from the same locality in Bra- of L. percarinatum throughout its geographic distribution; zil (Vila Rica) and found that the individuals have a trip- 2. Compare it with the morphological variation found loid karyotype 3n = 66 (30M+36m). The karyotype of two in the male specimens from SIRN and TBC, in order to other species of the parietale group known at that time, detect the presence (or absence) of autapomorphies that Leposoma osvaldoi Avila-Pires, 1995 and L. guianense, both could support the description of a potential new bisexual with 2n = 44 (20M+24m: Pellegrino et al., 1999) pointed species of Leposoma. to the possibility that the origin of the triploid karyotype Despite the strong evidence that the name Leposoma involved a hybridization event between a bisexual species percarinatum is currently applied to more than one species with a L. guianense/L. osvaldoi-like karyotype and a yet or lineages of parthenogenetic clones (Avila-Pires, 1995; to be discovered (Pellegrino et al., 2003) cryptic diploid Pellegrino et al., 2011), we chose to be conservative re- unisexual clone of L. percarinatum (2n = 44, 20M+24m). garding this taxonomic issue and treat the variants as a Subsequently, L. ferreirai Rodrigues and Avila-Pires, 2005 single evolutionary unit. This procedure is justified pri- was described based on specimens from Arquipelago de marily by the fact that the different lineages of L. percari‑ Anavilhanas, a fluvial archipelago of lower Rio Negro, natum sensu lato were recovered as a monophyletic group state of Amazonas, Brazil (Rodrigues and Avila-Pires, (Pellegrino et al., 2011). Also, it is very likely that complex 2005). The discovery of the hypothesized unisexual dip- events (e.g., multiple hybridization events) may have oc- loid form of L. percarinatum in the same geographic region curred during the evolutionary history of L. percarinatum, of L. ferreirai by Laguna et al. (2010) led the authors to and this scenario could not be fully understood with mor- propose that the unisexual diploid clone might be the re- phological data alone. Rather, we prefer only to describe sult of a hybridization event between L. ferreirai and L. os‑ the variation observed in unisexual and bisexual popula- valdoi in the lower Rio Negro region. tions and evaluate the degree of overlap between them The last relevant piece of this puzzle was provided in order to decide whether the male specimens should be by Pellegrino et al. (2011). Based on Bayesian and maxi- classified as a bisexual population of L. percarinatum or mum likelihood phylogenetic analyses (using three mi- as a potential new species. Both outcomes have impor- tochondrial and one nuclear gene regions), the authors tant consequences for our understanding of the origins found that Leposoma percarinatum is a complex of species of parthenogenesis in Leposoma. Thus, we discuss our composed of two divergent lineages that correspond to results not only from a taxonomic perspective, but also the previously characterized diploid and triploid clones from a historical one (although limited), that is, what our (Pellegrino et al., 2011). Despite these recent major ad- findings