Bahamas Saltflats (Holocene of Bahamas)

Where: San Salvador, Bahamas (24.1° N, 74.5° W: paleocoordinates 24.1° N, 74.5° W)

• coordinate stated in text

When: Holocene (0.0 - 0.0 Ma)

• It is not known how much time is represented by the death assemblages used in this study, but assemblages collected in comparable settings yielded radiocarbon ages between 0 and 4805 years and represented time spans between 175 years in the Bahamas and 3085 years in Baja California (Taft and Harbaugh 1964). Strasser and Samankassou (2003) dated Holocene shell material in lagoonal and intertidal settings in Florida Bay and Bermuda at about 1000 to 5600 years and calculated sediment accumulation rates ranging from 0.5 to 1.1 mm/a. However, their samples derived from deeper sediments (65 to 130 cm) than the material used in this study, which was collected from the seafloor.

Environment/lithology: marine; poorly lithified, sandy carbonate

• Graham’s Harbor is located windward and is here classified as a moderate-energy setting. Plant communities in these settings also include green algae commonly associated with tropical and subtropical seagrass meadows, such as

•Halimeda and Penicillus. The third vegetated sample locality is situated at Pigeon Creek (PC), a tidal inlet at the southeastern end of the island (Fig. 1B). Pigeon Creek experiences strong current velocities of up to 25 m/min near the inlet channel, and about 11 m/min at the sampling locality. Two additional sampling localities represent unvegetated sandflats in front of small patch reefs and are located at Monument Beach (MB) and Grotto Beach (GB).

• Both localities represent scarcely to moderately well-vegetated seagrass-dominated sandflats.

Size classes: macrofossils, mesofossils, microfossils

• Observed taphonomic features of the present shells are fragmentation, edge rounding, abrasion, and carbonate coating (Fig. 3). The number of indeterminate gastropods as an indication for taphonomic alteration ranges from 0 to 64 (Table 2).

Collection methods: surface (in situ), sieve,

• Sampling at all five localities was carried out within a 0.25 meters squared large frame using the same sieve (mesh width = 1 mm, d = 30 cm). Samples were washed over a 1 mm sieve, dried, and sorted for shells. The volume of sediment residue that was sorted to yield 200 specimens was weighed, and the number of specimens was divided by the weight of sorted material, and used as an estimate of shell abundance.

Primary reference: S. Reich. 2014. Gastropod Associations as a Proxy for Seagrass Vegetation in a Tropical, Carbonate Setting (San Salvador, Bahamas). Palaios 29(9):467-482 [M. Uhen/M. Bean]more details

Purpose of describing collection: taphonomic analysis

PaleoDB collection 173828: authorized by Mark Uhen, entered by Meredith Bean on 16.10.2015

Creative Commons license: CC BY (attribution)

Taxonomic list

• A total of 200 gastropods were randomly picked from each sample including incomplete specimens and fragments if a part of the columella was preserved. Fragments representing more than one whorl were included in the analysis and counted for one individual. Only two living gastropods were found among 4690 picked shells, and they were excluded from the analysis. The material is housed in the fossil Mollusca collection at Naturalis Biodiversity Center (Leiden, The Netherlands); illustrated specimens are registered using RGM-numbers (RGM 5 Rijksmuseum van Geologie en Mineralogie, former name of Naturalis).
Gastropoda
 Cerithioidea - Cerithiidae
Cerithium eburneum Bruguière 1792 cerith snail
Cerithium litteratum Born 1778 cerith snail
Cerithium lutosum Menke 1828 cerith snail
 Cerithioidea - Scaliolidae
Finella adamsi Dall 1889 snail
 Neogastropoda - Marginellidae
Dentimargo reductus margin shell
 Neogastropoda - Mangeliidae
Granoturris sp. Fargo 1953 snail
 Neogastropoda - Columbellidae
Columbella mercatoria Linnaeus 1758 snail
 Sorbeoconcha - Rissoidae
Rissoina sp. d'Orbigny 1840 snail
 Patellogastropoda -
 Opisthobranchia - Bullidae
"Bulla occidentalis" = Bulla striata
"Bulla occidentalis" = Bulla striata Bruguiére 1792 snail
 Opisthobranchia - Cylichnidae
Acteocina spp. Gray 1847 barrel-bubble
 Opisthobranchia - Haminoeidae
Atys sharpi snail
includes Atys. sp. specimens
 Trochoidea - Phasianellidae
 Trochoidea - Tegulidae
 Trochoidea - Turbinidae
Arene sp. Adams and Adams 1854 snail
 Neritoidea - Neritidae
Smaragdia viridis Linnaeus 1758 snail