In the intimacy of the darkness: genetic polyandry in deep-sea luminescent lanternsharks Etmopterus spinax and Etmopterus molleri (Squaliformes, Etmopteridae)

Multiple paternity seems common within elasmobranchs. Focusing on two deep-sea shark species: the velvet belly lanternshark, <em>Etmopterus spinax</em>, and the slendertail lanternshark, <em>Etmopterus molleri</em>, we inferred the paternity in 31 <em>E. spinax</em> litters from Norway (3-18 embryos per litter) and 6 <em>E. molleri</em> litters from Japan (3-6 embryos), using 21 and 10 specific microsatellites, respectively. At least two <em>E. spinax</em> litters were sired from multiple fathers each, with highly variable paternal skew (1:1 to 9:1). Conversely, no clear signal of genetic polyandry was found in <em>E. molleri</em>. This dataset contains the microsatellite genotypes analysed (281 <em>E. spinax</em> × 29 loci; 42 <em>E. molleri</em> × 19 loci).