Species New to Science

Archaic dolphin could hear high frequency sounds

The Earth's polar regions are low rates of inter- and intraspecific diversification. An extreme mammalian example is the Arctic ringed seal (Pusa hispida hispida), which is assumed to be panmictic across its circumpolar Arctic range. Yet, local Inuit communities in Greenland and Canada recognize several regional variants; a finding supported by scientific studies of body size variation. It is however unclear whether this phenotypic variation reflects plasticity, morphs or distinct ecotypes. Here, we combine genomic, biologging and survey data, to document the existence of a unique ringed seal ecotype in the Ilulissat Icefjord (locally ‘Kangia’), Greenland; a UNESCO World Heritage site, which is home to the most productive marine-terminating glacier in the Arctic. Genomic analyses reveal a divergence of Kangia ringed seals from other Arctic ringed seals about 240 kya, followed by secondary contact since the Last Glacial Maximum. Despite ongoing gene flow, multiple genomic regions appear under strong selection in Kangia ringed seals, including candidate genes associated with pelage coloration, growth and osmoregulation, potentially explaining the Kangia seal's phenotypic and behavioural uniqueness. The description of ‘hidden’ diversity and adaptations in yet another Arctic species merits a reassessment of the evolutionary processes that have shaped Arctic diversity and the traditional view of this region as an evolutionary freezer. Our study highlights the value of indigenous knowledge in guiding science and calls for efforts to identify distinct populations or ecotypes to understand how these might respond differently to environmental change.

The discovery of a distinct ringed seal ecotype in the Ilulissat Icefjord adds to a growing list of Arctic marine species with newly detected genetic and/or phenotypic diversity (Bringloe et al., 2020; Jacobsen et al., 2022; Laidre et al., 2022; Madsen et al., 2016; Mathiesen et al., 2017; Tempestini et al., 2020). The Arctic environment is highly dynamic, with marine systems characterized by long- and short-term fluctuations in glacial extent and run-off, marine-freshwater clines, sea-level changes and isostatic rebound. These processes might facilitate both regional and local speciation, perhaps down to the scale of individual fjord systems or larger marine-terminating glacier fronts. Thus, while our study is the first to demonstrate the existence of a distinct Kangia ringed seal ecotype in the Ilulissat Icefjord, similar intraspecific diversity and differentiation may exist elsewhere in both ringed seals and other Arctic marine species. Across the Arctic, marine-terminating glaciers, deep fjord systems and polynyas sustain high biological productivity and provide important foraging and resting habitats for marine organisms (Heide-Jørgensen et al., 2016; Lydersen et al., 2014; Meire et al., 2017). These areas may have constituted important high-latitude refugia and even micro-evolutionary speciation factories through glacial and interglacial periods, potentially supporting uniquely adapted populations of otherwise wide-spread and seemingly panmictic Arctic marine organisms. Some local populations may not easily respond to climate change by simply tracking their habitat northward, whereas others may harbour the adaptive potential providing species-level resistance to current climate warming. Our findings highlight the need for dedicated scientific efforts and thorough sampling to record and understand regional and local drivers of intraspecific diversity in the Arctic to provide information for nature management.

Keywords: Mysticeti, Chaeomysticeti, Southern Hemisphere, body size, gigantism

Top marine predators, such as odontocetes, pinnipeds, and seabirds, are known to forage around fishing boats as fishermen aggregate and/or discard their prey. Recently, incidents of humpback whales interacting with fishing boats have been reported. However, whether humpback whales utilise discard fish as a food source and how they forage around fishing boats is unknown. This study reports, for the first time, the foraging behaviour of a humpback whale around fishing boats. Three whales were tagged using a suction-cup tag containing a video camera, and a behavioural data logger in the coastal area of Tromsø, Norway. Video data from one tagged whale showed that the whale remained in close vicinity of fishing boats for 43 min, and revealed the presence of large numbers of dead fish, fish-eating killer whales, fishing boats, and fishing gear. In waters with large numbers of dead fish, the whale raised its upper jaw, a motion associated with engulfing discard fish from fishing boats, and this feeding behaviour differed markedly from lunge-feeding observed in two other whales in the same area. This behaviour was defined as “pick-up feeding”. No lunge feeding was seen on the data logger when the whale foraged around fishing boats. This study highlights a novel humpback whale foraging strategy: low energy gain from scattered prey but also low energy costs as high-energy lunge feeding is not required.

Keywords: biologging, energy cost, feeding behaviour, fisheries interaction, humpback whales

CETACEA Brisson, 1762

ODONTOCETI Flower, 1867

Genus - From the Māori language, ‘Niho’ for teeth and ‘Hae’ for slashing, in reference to possible use of the teeth.

Species - From the Māori language, ‘Mata’ for face/point and ‘Koi’ for sharp, in reference to the long, flat and thin rostrum ending in pointed sharp teeth.

Pronunciation guide – nee-ho-ha-eh ma-ta-koy

A. P. B. Costa, F. I. Archer, P. E. Rosel and W. F. Perrin. 2022. Tursiops truncatus nuuanu, A New Subspecies of the Common Bottlenose Dolphin from the eastern tropical Pacific. Journal of Mammalian Evolution. DOI: 10.1007/s10914-022-09641-5 

  Researchgate.net/publication/366182096_Tursiops_truncatus_nuuanu_a_new_subspecies_of_the_common_bottlenose_dolphin_from_the_eastern_tropical_Pacific