Benthic Foraminiferal Morphogroups on the Argentine Continental Shelf

Abstract

The aim of this study is to evaluate the relative influence of abiotic factors on the association and spatial distribution of recent benthic foraminiferal morphogroups in the Argentine continental shelf at ,40uS environments as a first step towards establishing their paleoecological significance. Foraminifera are classified into five morphogroups: tapered, elongateflattened, milioline, planoconvex, and rounded-planispiral. Compositional data analysis techniques were used to define morphogroup assemblages, and Classification and Regression Tree Analysis was used to identify environmental variables. The distribution of the morphogroup assemblages were recognized was driven by complex interactions between environmental factors. The most important factor is temperature, although salinity, substrate grain size, and hydrodynamic energy also correlate with the distribution of morphogroups. The morphogroups analysis shows potential for determining present and past environments where the autoecology of the species is unknown or where there is doubt regarding their taxonomic classification.

Ontogenetic morphogenesis and biogeographic patterns: resolving taxonomic incongruences within “species” of Buccella from South American coastal waters

“…This species of Buccella is widely distributed in the Bahía Blanca estuary (Cusminsky et al, 2006(Cusminsky et al, , 2009Calvo-Marcilese et al, 2011). It has also been recorded in Holocene material from Bahía Blanca (see sections N1, PS2B2, CdM, C3B in the Figure 1 of this paper, and Gómez et al, 2005;Cusminsky et al, 2009;Calvo-Marcilese et al, 2011) and from late Holocene deposits along north-and south-eastern Buenos Aires province (Boltovskoy, 1970(Boltovskoy, , 1976Laprida, 1998;Laprida et al, 2007;Ferrero, 2006;Alperin et al, 2011). In present-day Bahía Blanca estuary material, Buccella is widely distributed in subtidal and inner shelf environments but has rarely been recovered from intertidal habitats (Cusminsky et al, 2006;Calvo-Marcilese & Pratolongo, 2009).…”

Foraminiferal paleodiversity and paleoenvironments at the NE coastal plain of Buenos Aires province (Argentina) during the Mid-Holocene sea level highstand

“…According to Usera and Blázquez-Morilla (1997), the resistance to erosion of shells in the Order Miliolida favors their relative abundance. Alperin et al (2011) and Bernasconi, 2020) reported that epifaunals as miliolids are associated to sandy sediments and high-energy environments. Genera that get attached to the substrate, such as Quinqueloculina spp.…”

“…This increase in the infaunal forms is probably due to the presences of muddy sediment that prevails in this upper part of the sequence. In addition, Bernasconi and Cusminsky (2009), Bernhard et al (1997), Hayward et al (2002), Sen Gupta and Machain-Castillo (1993), Smart (2002), and Alperin et al (2011) concluded that some Bolivina, Bulimina and other biserial species are adapted to living in zones with minimum oxygen levels. The increase in these infaunal species together with the data obtained from the indexes would reflect eutrophic conditions with lower oxygenation.…”

The contribution of functional traits to the understanding of palaeoenvironmental changes

“…The assessed morphological diversity is consequently above the species level. Simplification of information is a risk of the morphological group approach (Read et al, 2014), but it provides access to a partition of variability that is potentially more informative ecologically than taxonomically when the studied biological object is sensitive to environmental change (Alperin, Cusminsky, & Bernasconi, 2011;Read et al, 2014;Khare et al, 2017), which is the case for shrew mandibles (Badyaev & Foresman, 2000;Young et al, 2010). The morphological groups reveal variations in the number of morphotypes independent of the number of species.…”