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Genetics and shell morphometrics of assimineids (Mollusca, Caenogastropoda, Truncatelloidea) in the St Lucia Estuary, South Africa.

Miranda NA, van Rooyen R, MacDonald A, Ponder W, Perissinotto R - Zookeys (2014)

Bottom Line: The Assimineidae are a family of amphibious microgastropods that can be mostly found in estuaries and mangroves in South Africa.These two taxa exhibit patterns of spatial overlap that appear to vary depending on environmental parameters, particularly salinity.The need to resolve the complex taxonomy of assimineids is highlighted.

View Article: PubMed Central - HTML - PubMed

Affiliation: DST/NRF Research Chair in Shallow Water Ecosystems, c/o Department of Zoology, Nelson Mandela Metropolitan University, P O Box 77000, Port Elizabeth, 6031, South Africa.

ABSTRACT
The Assimineidae are a family of amphibious microgastropods that can be mostly found in estuaries and mangroves in South Africa. These snails often occur in great numbers and are ecologically important to the St Lucia Estuary, which forms a crucial part of the iSimangaliso Wetland Park, a UNESCO World Heritage Site. Genetic and shell morphometric analyses were conducted on individuals collected from nine localities distributed from the northern lake regions to the southern lake and the mouth of the St Lucia estuarine lake. Mitochondrial (COI) and nuclear (28S) DNA was used to construct Bayesian Inference, Neighbour-joining, Maximum Parsimony and Maximum Likelihood trees. Principal Component Analysis and Cluster Analysis were performed on standard shell parameter data. Results indicate that two different taxa are present in St Lucia. The taxon comprising individuals from the South Lake and St Lucia Estuary Mouth is identified as Assiminea cf. capensis Bartsch, in accordance with the latest taxonomic consensus. The taxon comprising assimineid individuals from False Bay, North Lake and South Lake, is here tentatively named "Assiminea" aff. capensis (Sowerby). These two taxa exhibit patterns of spatial overlap that appear to vary depending on environmental parameters, particularly salinity. The need to resolve the complex taxonomy of assimineids is highlighted.

No MeSH data available.


Related in: MedlinePlus

Map of St Lucia Estuary. Sample localities are indicated by arrows and dots (Modified from Miranda et al. 2010).
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Figure 1: Map of St Lucia Estuary. Sample localities are indicated by arrows and dots (Modified from Miranda et al. 2010).

Mentions: Study Site. The St Lucia Estuary (28°23'S, 32°24'E) covers an area of approximately 350 km2 (Taylor et al. 2006) and is Africa's largest estuarine lake (Cyrus 1988). The system is comprised of three large shallow (average 0.9 m depth) lakes, namely False Bay, North Lake and South Lake (Fig. 1). Salinities can range from oligohaline (salinity 0-5) to hypersaline levels (salinity >100) over the course of a number of years (Day et al. 1954; Cyrus 1988, 2010). During periods of low freshwater input and high evaporative water loss, the system exhibits a reverse salinity gradient: a lower salinity can be recorded in the southern regions closer to the mouth, whereas the northern regions of the system tend to become hypersaline. Droughts occur on an almost decadal basis (Taylor et al. 2006). At the time of the present study, St Lucia was emerging from the most severe drought event on record. This dry period ended with freshwater input from Cyclone Irina in March 2012, which led to a system-wide drop in salinity resulting in near marine levels in the northern regions and fresh and brackish conditions prevailing in the southern regions of the system.


Genetics and shell morphometrics of assimineids (Mollusca, Caenogastropoda, Truncatelloidea) in the St Lucia Estuary, South Africa.

Miranda NA, van Rooyen R, MacDonald A, Ponder W, Perissinotto R - Zookeys (2014)

Map of St Lucia Estuary. Sample localities are indicated by arrows and dots (Modified from Miranda et al. 2010).
© Copyright Policy - creative-commons-attribution
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109452&req=5

Figure 1: Map of St Lucia Estuary. Sample localities are indicated by arrows and dots (Modified from Miranda et al. 2010).
Mentions: Study Site. The St Lucia Estuary (28°23'S, 32°24'E) covers an area of approximately 350 km2 (Taylor et al. 2006) and is Africa's largest estuarine lake (Cyrus 1988). The system is comprised of three large shallow (average 0.9 m depth) lakes, namely False Bay, North Lake and South Lake (Fig. 1). Salinities can range from oligohaline (salinity 0-5) to hypersaline levels (salinity >100) over the course of a number of years (Day et al. 1954; Cyrus 1988, 2010). During periods of low freshwater input and high evaporative water loss, the system exhibits a reverse salinity gradient: a lower salinity can be recorded in the southern regions closer to the mouth, whereas the northern regions of the system tend to become hypersaline. Droughts occur on an almost decadal basis (Taylor et al. 2006). At the time of the present study, St Lucia was emerging from the most severe drought event on record. This dry period ended with freshwater input from Cyclone Irina in March 2012, which led to a system-wide drop in salinity resulting in near marine levels in the northern regions and fresh and brackish conditions prevailing in the southern regions of the system.

Bottom Line: The Assimineidae are a family of amphibious microgastropods that can be mostly found in estuaries and mangroves in South Africa.These two taxa exhibit patterns of spatial overlap that appear to vary depending on environmental parameters, particularly salinity.The need to resolve the complex taxonomy of assimineids is highlighted.

View Article: PubMed Central - HTML - PubMed

Affiliation: DST/NRF Research Chair in Shallow Water Ecosystems, c/o Department of Zoology, Nelson Mandela Metropolitan University, P O Box 77000, Port Elizabeth, 6031, South Africa.

ABSTRACT
The Assimineidae are a family of amphibious microgastropods that can be mostly found in estuaries and mangroves in South Africa. These snails often occur in great numbers and are ecologically important to the St Lucia Estuary, which forms a crucial part of the iSimangaliso Wetland Park, a UNESCO World Heritage Site. Genetic and shell morphometric analyses were conducted on individuals collected from nine localities distributed from the northern lake regions to the southern lake and the mouth of the St Lucia estuarine lake. Mitochondrial (COI) and nuclear (28S) DNA was used to construct Bayesian Inference, Neighbour-joining, Maximum Parsimony and Maximum Likelihood trees. Principal Component Analysis and Cluster Analysis were performed on standard shell parameter data. Results indicate that two different taxa are present in St Lucia. The taxon comprising individuals from the South Lake and St Lucia Estuary Mouth is identified as Assiminea cf. capensis Bartsch, in accordance with the latest taxonomic consensus. The taxon comprising assimineid individuals from False Bay, North Lake and South Lake, is here tentatively named "Assiminea" aff. capensis (Sowerby). These two taxa exhibit patterns of spatial overlap that appear to vary depending on environmental parameters, particularly salinity. The need to resolve the complex taxonomy of assimineids is highlighted.

No MeSH data available.


Related in: MedlinePlus