Angursa, , Fujimoto and Hansen, 2019

Trokhymchuk, Roman & Kieneke, Alexander, 2025, Novel distribution records of marine Tardigrada from abyssal sediments of the Northwest Atlantic Ocean, Organisms Diversity & Evolution 25 (1), pp. 13-28 : 25

Biogeography of Angursa

As a result of their taxonomic revision of the genus Angursa , especially with regard to the two species A. abyssalis and A. bicuspis, Fujimoto and Hansen (2019) needed to reconsider the biogeography of these two and further species (see also Fig. 8 of Fujimoto & Hansen, 2019). As a result, verified records of A. abyssalis so far only exist from the type locality off Angola (2063 m depth) and from the Northeast Atlantic (2205 m depth). All remaining records of “ A. abyssalis ” probably represent different species and should be considered just as “ Angursa sp. ”; see above ( Fujimoto & Hansen, 2019). Hence, our record of A. abyssalis from the Newfoundland Basin represents the third verified record of this species. Altogether, these three records imply an Atlantic-wide abyssal distribution of A. abyssalis . Concerning further species of Angursa, Fujimoto and Hansen (2019) concluded that most species (i.e., A. antarctica , A. capsula , A. lanceolata , and A. seisuimaruae ) are so far only reported from their type localities and therefore their distribution areas may be limited by known dispersal barriers. Our results may considerably change this opinion, since we also found Angursa capsula and A. lanceolata in the deep-sea sediment of the Newfoundland Basin! For both species, these are the first records after the original species descriptions. In the case of A. lanceolata , this new data point may imply, as in A. abyssalis , an Atlantic-wide distribution. For A. capsula , our finding in the abyssal sediment of the Northwest Atlantic is even more remarkable, because that species was so far only known from the Pacific deep sea off the Peruvian coast ( Bussau, 1992). A record from two ocean basins may even imply a cosmopolitan (deep-sea) distribution of A. capsula . However, for the comparable scenario of Angursa lingua (type locality in the Pacific deep sea off Peru, Bussau, 1992; further record from the Brazilian Atlantic shelf, Da Rocha et al., 2013), such a distant distribution was challenged due to the Panama Isthmus that separates both localities in the Pacific and Atlantic deep sea ( Fujimoto & Hansen, 2019; Kaczmarek et al., 2015). However, we want to point to the fact that both ocean basins have certain connectivity via the Southern Ocean and also via the Bering Strait. Of course, there are also potential barriers in the form of submarine ridges and shallow depths, but at least in the case of harpacticoid Copepoda, submarine ridges were demonstrated not to act as dispersal barriers ( Menzel et al., 2011). In limno-terrestrial tardigrades, several cosmopolitan genera and species are known and cosmopolitism is thought to be correlated with parthenogenetic reproduction and the ability of cryptobiosis ( Artois et al., 2011). If such capacities also occur in the life cycle of species of Angursa is absolutely unknown. In the course of potential cosmopolitan versus endemic distribution, future research also needs to include the analysis of DNA sequence data in order to reveal complexes of cryptic genetic species and to estimate the level of gene flow ( Fujimoto & Hansen, 2019).