First record of a male of Kryptolebias hermaphroditus Costa, 2011 (Cyprinodontiformes: Cynolebiidae)

Abstract

During an ichthyological survey in September 2015 at the Ceará-Mirim River estuary, Rio Grande do Norte State, northeastern Brazil, we collected a male of Kryptolebias hermaphroditus, a cynolebiid species that had been previously described as containing exclusively self-fertilizing hermaphrodites. This is the first record of a male in this species, over 140 years after the discovery of the mangrove rivulid species from Brazil. Our discovery reinforces the need for more studies in K. hermaphroditus, as well as the potential of this species as a model for evolutionary studies due to its unique mating system. Durante uma amostragem ictiológica em setembro de 2015 no estuário do rio Ceará-Mirim, Estado do Rio Grande do Norte, Nordeste do Brasil, nós coletamos um macho de Kryptolebias hermaphroditus, uma espécie de rivulídeo que foi descrita como contendo apenas hermafroditas auto-fertilizantes. Este é o primeiro registro de um macho dessa espécie, mais de 140 anos depois da descoberta das espécies de rivulídeos de manguezais do Brasil. Nossa descoberta reforça a necessidade de mais estudos em K. hermaphroditus, assim como, o potencial desta espécie como um modelo para estudos evolutivos devido ao seu sistema reprodutivo único.

Local parasite pressures and host genotype modulate epigenetic diversity in a mixed‐mating fish

“…A total of 128 specimens of K. hermaphroditus were collected using hand‐nets from three sampling sites on isolated mangroves on the northeastern coast of Brazil between January and September 2015: Ceará‐Mirim River—Site 1; Curimataú River—Site 2; Ipojuca River—Site 3 (Figure ). K. hermaphroditus is distributed along the Brazilian coast (Tatarenkov et al, ) and is typically found in shallow pools of high salinity levels (>30 ppt), clear waters, and muddy substrates, where there are few other sympatric fish (Berbel‐Filho et al, ; Lira, Paiva, Ramos, & Lima, ). All specimens displayed the common hermaphrodite phenotype (dark color with well‐defined ocellus on the caudal fin; Costa, ).…”

“…The genus Kryptolebias contains the only known mixed-mating vertebrate species (K. marmoratus and K. hermaphroditus), characterized by variable rates of selfing and outcrossing (Tatarenkov et al, 2017). Populations of both species consist mainly of self-fertilizing hermaphrodites and varying levels of males at low frequencies (Berbel-Filho, Espirito-Santo, & Lima, 2016;Tatarenkov et al, 2017), and exhibit high levels of homozygosity (Tatarenkov et al, 2017;Tatarenkov, Lima, Taylor, & Avise, 2009), suggesting that self-fertilization is the most common mode of reproduction .…”

Local parasite pressures and host genotype may modulate epigenetic diversity in a mixed-mating fish

“…1). K. hermaphroditus is distributed along the Brazilian coast (Tatarenkov et al 2017) and is typically found in shallow pools of high salinity levels (>30 ppt), clear waters and muddy substrates, where there are few other sympatric fish (Lira et al 2015; Berbel-Filho et al 2016). All specimens displayed the common hermaphrodite phenotype (dark colour with well-defined ocellus on the caudal fin; Costa 2011).…”

“…hermaphroditus ), characterised by variable rates of selfing and outcrossing (Tatarenkov et al 2017). Populations of both species consist mainly of self-fertilizing hermaphrodites and varying levels of males at low frequencies (Tatarenkov et al 2017; Berbel-Filho et al 2016), and exhibit high levels of homozygosity (Tatarenkov et al 2009, 2017), suggesting that self-fertilization is the most common mode of reproduction (Avise and Tatarenkov 2015).…”

More than meets the eye: syntopic and morphologically similar mangrove killifish species show different mating systems and patterns of genetic structure along the Brazilian coast

“…In the northernmost part of its distribution (Guanabara and Sepetiba Bays, 22° S), K. ocellatus is often syntopic (i.e. coexisting at the same habitat at the same time) with K. hermaphroditus , a species composed mostly of self-fertilising hermaphrodites and very rare males (Berbel-Filho et al, 2016;, resulting in occasional outcrossing but at very low frequencies (Berbel-Filho et al, 2019;Tatarenkov et al, 2017). Extremely low levels of genetic diversity in K. hermaphroditus, especially at the southernmost edge of its distribution (where it is syntopic with K. ocellatus), suggest relatively recent dispersal and colonisation of this species in south-eastern Brazil (Tatarenkov et al, 2009;.…”