Genetic evidence of cryptic speciation within hammerhead sharks (Genus Sphyrna)

A DNA Sequence–Based Approach To the Identification of Shark and Ray Species and Its Implications for Global Elasmobranch Diversity and Parasitology

“…These results suggest that undescribed diversity exists among scalloped hammerheads, which may include sympatric species. This result is consistent with those of a number of previous authors who also reported genetic diversity within S. lewini (e.g., Abercrombie et al, 2005;Duncan et al, 2006;Quattro et al, 2006;Zemlak et al, 2009).…”

How many species of goliath grouper are there? Cryptic genetic divergence in a threatened marine fish and the resurrection of a geopolitical species

“…Our data, along with other recent studies (e.g. Bass et al 2005, Quattro et al 2006, Vianna et al 2006 clearly show that the phenomenon of hidden genetic divergence is not restricted to understudied or difficult-tostudy organisms, as has been the basis of conventional wisdom. In fact, goliath grouper are at the forefront of conservation efforts, as is evidenced by their presence as the focus of recent symposia, their listing by the IUCN as 'Critically Endangered,' their prior listing as a species of concern in US waters by US Fish and Wildlife Service, and a moratorium on their capture in both Brazil and the US.…”

“…Although this phenomenon was thought to occur most commonly in small or difficult-to-study organisms, recent evidence shows that these cryptic genetic lineages also occur amongst Earth's largest and most well-studied marine animals (e.g. Bass et al 2005, Quattro et al 2006, Vianna et al 2006. In addition, these genetic studies often elucidate genetic patterns that reflect demographic connectivity, a critical aspect of population biology that is often unknown but imperative for effective conservation strategies.…”

<p class="HeadingRunIn"><strong><em>Sphyrna gilberti</em> sp. nov., a new hammerhead shark (Carcharhiniformes, Sphyrnidae) from the western Atlantic Ocean</strong></p>

“…Cryptic speciation is an increasingly common interpretation of genetic variation and gene tree reconstructions for broadly distributed but morphologically conservative taxa (Quattro et al 2006). Among fishes, a striking example of genetic divergence in the face of morphological conservatism was the discovery that the bonefish, Albula vulpes (Linnaeus 1758), was actually a complex of eight sibling species (Colborn et al 2001).…”

“…Among fishes, a striking example of genetic divergence in the face of morphological conservatism was the discovery that the bonefish, Albula vulpes (Linnaeus 1758), was actually a complex of eight sibling species (Colborn et al 2001). Although less dramatic, five independent studies of genetic variation (Abercrombie et al 2005;Quattro et al 2006;Zemlak et al 2009;Naylor et al 2012;Pinhal et al 2012) confirmed a deep evolutionary partition among samples morphologically assignable to the scalloped hammerhead, Sphyrna lewini (Griffith & Smith 1834), which is globally distributed in tropical, subtropical, and temperate marine waters. Specifically, a subset of samples from the western Atlantic Ocean was genetically divergent, e.g., 3-7% in mitochondrial control region haplotypes, and constituted an independent evolutionary lineage in gene trees.…”