First Genetic Record of a Strap-Toothed Beaked Whale (Mesoplodon layardii) Stranding in Chile

Abstract

Of all the cetacean families, the Ziphiidae are one of the most enigmatic (MacLeod, 2018). They are the second most diverse family after the Delphinidae (Dalebout et al., 2002). They dive very deep for prolonged periods, spending little time at the sur-face between dives; and they live predominantly offshore in oceanic waters (MacLeod & D’Amico, 2006), which makes studying them more difficult and explains why they are so poorly understood (MacLeod, 2018). Most of the studies regarding ziphiids have been carried out on stranded individ-uals (Rosario-Delestre et al., 1999; Dalebout et al., 2002). Certain key features of the Ziphiidae, such as the location and shape of male tusks (MacLeod, 1998, 2018; MacLeod & Herman, 2007; Pitman, 2018), facilitate species identification, particularly within the cryptic genus Mesoplodon (MacLeod, 2018); however, similarities among species and poor knowledge of body color patterns can lead to misidentification, especially in the case of female and juvenile specimens as body color patterns are to some extent unknown and are similar between females and juveniles (Pitman, 2018). In general, a molecular genetic analysis is considered the most reliable method for species identification (Kim et al., 2019).

Of all the cetacean families, the Ziphiidae are one of the most enigmatic (MacLeod, 2018). They are the second most diverse family after the Delphinidae (Dalebout et al., 2002). They dive very deep for prolonged periods, spending little time at the sur-face between dives; and they live predominantly offshore in oceanic waters (MacLeod & D’Amico, 2006), which makes studying them more difficult and explains why they are so poorly understood (MacLeod, 2018). Most of the studies regarding ziphiids have been carried out on stranded individ-uals (Rosario-Delestre et al., 1999; Dalebout et al., 2002). Certain key features of the Ziphiidae, such as the location and shape of male tusks (MacLeod, 1998, 2018; MacLeod & Herman, 2007; Pitman, 2018), facilitate species identification, particularly within the cryptic genus Mesoplodon (MacLeod, 2018); however, similarities among species and poor knowledge of body color patterns can lead to misidentification, especially in the case of female and juvenile specimens as body color patterns are to some extent unknown and are similar between females and juveniles (Pitman, 2018). In general, a molecular genetic analysis is considered the most reliable method for species identification (Kim et al., 2019).