Geographic ranges and the hypothesis of the dispersal of the fishes of superfamily Congiopodoidea (Pisces: Scorpaenoidei) with the Antarctic Circumpolar Current

Abstract

The most probable habitat of the ancestor of the superfamily Congiopodoidea Gill, 1889 is the area of the modern Malay Archipelago and Australia; the paths of further distribution as well as places of origin of taxa of different ranks within the superfamily are shown here based on morphological data. The dispersal of Congiopodoidea most likely occurred via the cold Antarctic Circumpolar Current, while members of the sister clade, the family Synanceiidae Swainson, 1839, occupied new habitats primarily in a northerly direction. Fishes of both families of Congiopodoidea (Congiopodidae Gill, 1889 and Zanclorhynchidae Andriashev, 1993) occupied new habitats only eastward of Australia, thus Zanclorhynchus spinifer heracleus Zhukov et Balushkin, 2018 appeared at the modern distribution area in the Ridge of Hercules in the Pacific Sector of the Southern Ocean after the ancestral forms had overcome more than a round-the-world migration. Six species of the genus Congiopodus Perry, 1811 have pairwise sympatric distribution ranges. They apparently originated on the shelves of Australia – C. leucopaecilus (Richardson, 1846), C. coriaceus Paulin et Moreland, 1979, and southern South America – C. peruvianus (Cuvier, 1829), C. kieneri (Sauvage, 1878), C. torvus (Gronow, 1772) and C. spinifer (Smith, 1839); moreover, the last two migrated further – to the southern point of the African continent. In the family Zanclorhynchidae, the monotypic genus Alertichthys Moreland, 1960 remained close to the place of radiation of the ancestral forms of the superfamily; its modern range covers seamounts and shelfs of islands south of New Zealand. The path of the ancestral forms of the second genus of this family, Zanclorhynchus Günther, 1880 was much longer. The most probable place of its origin is the waters of southern part of South America, from here the ancestral form migrated to the Prince Edward Islands in the Indian Ocean sector of the Southern Ocean, where it differentiated into two species Z. spinifer Günther, 1880 and Z. chereshnevi Balushkin et Zhukov, 2016. Zanclorhynchus spinifer further continued to occupy more eastern shelfs of islands and seamounts within the Antarctic Circumpolar Current, dividing into four subspecies: Z. spinifer armatus Zhukov, 2019, Z. spinifer spinifer Günther, 1880, Z. spinifer macquariensis Zhukov, 2019, and Z. spinifer heracleus. The hypothesis about the possibility of the distribution with the Antarctic Circumpolar Current as a dispersive agent is confirmed by morphological data, when the sequence of occupation of modern habitats is considered through the degree of relatedness of the fish inhabiting them.