Modern benthic ostracodes from Lutzow-Holm Bay, East Antarctica: paleoceanographic, paleobiogeographic, and evolutionary significance

Abstract

Seventy-three ostracode species from 38 genera were recovered from the 55 surface sediment samples in Lützow-Holm Bay, northeastern Antarctica. We investigated bathymetric and geographic distributions of modern benthic ostracode species in the bay and compared this fauna with published modern and fossil ostracode data of Antarctic and southern South American regions. The results show: (1) Four biotopes and three sub-biotopes are recognized based on Q-mode cluster analysis, which suggest distributions of modern ostracodes are mainly controlled by water-mass structure, ice scouring, and light availability. (2) Comparison between the Lützow-Holm Bay fauna and other ostracode faunas from Antarctica and southern South America shows high endemism and homogeneity of Antarctic ostracode fauna, suggesting in situ evolution of most extant Antarctic species. (3) Most species are endemic to the Antarctica, a few species also inhabit South American waters.

Southern Polar Front macroecological and biogeographical insights gained from benthic Ostracoda

“…A few studies, however, suggest that depth, water-mass structure, ice scouring, and light availability play important roles on the alpha and beta benthic and benthopelagic ostracod diversity (Majewski and Olempska, 2005;Yasuhara et al, 2007;Brandão, 2008Brandão, , 2010.…”

The Lower Miocene cytherellids (Crustacea, Ostracoda) from the Pelotas Basin and their significance for the South Atlantic Paleozoogeography

“…In the Quaternary, genera such as Philoneptunus, Javanella and Clinocythereis, as well as some species such as Cytheropteron lobatulum Ayress et al, 1996, Philoneptunus provocator Jellinek & Swanson, 2003and, probably, Clinocythereis australis Ayress & Swanson, 1991, all described in Oceania, were registered in Santos Basin, Southeast Brazil (Bergue et al, 2006;Bergue & Coimbra, 2008). Yasuhara et al (2007) reports a similar pattern for Cativella bensoni Neale, 1967 and Abyssocythere antarctica (Nealy, 1967) also in the circum-Antarctic region. Though the wide temporal range ascribed to those two species (Oligocene to Recent) might be questionable (see discussion in Bergue et al, 2013) the data provided by Yasuhara and colleagues support that the circum-Antarctic dispersion had already been stablished at least in the Neogene, even before the complete opening of the Drake Passage.…”

Southern Ocean areas of endemism: a reanalysis using benthic hydroids (Cnidaria, Hydrozoa)

“…On the other hand, there are historical similarities of the Antarctic fauna to those from northern regions (Cañete et al, 1999;Yasuhara et al, 2007;Kaiser et al, 2011), mainly in the Antarctic Peninsula and the subantarctic region of South America (Clarke & Johnston, 2003;Clarke et al, 2005). The connection between both continents is through the Scotia Arc, and since it will have influenced dispersal of their marine fauna, we may question exactly how isolated was the SO (Clarke et al, 2005).…”

“…These notmutually-independent hypotheses are partially supported by fauna and geography and have been contrasted with abiotic factors of the SO (viz., Beu et al, 1997;Cañete et al, 1999;Yasuhara et al, 2007;Kaiser et al, 2011).…”