Fig 1.
Location of trace fossil in this study.
(A) The Bahamas archipelago north of Cuba and east of Florida, with San Salvador Island (SSI) indicated. (B) San Salvador Island, with study area on southern end of island (box); dark- and light-blue areas are inland lakes. (C) Location of trace fossil (TF) investigated in this study in roadcut north of The Gulf, at N 23° 56.832’, W 74° 30.654.’ Image in Fig 1A downloaded from Natural Earth (https://www.naturalearthdata.com/), released into public domain and retrieved October 29, 2020, used in Photoshop. Image in Fig 1B from European Space Agency (ESA) Sentinel-2 Satellite, January 2019 image of San Salvador Island from IDL1C_T18QWM_A018555_20190110T154545, (https://earthexplorer.usgs.gov/), released in public domain and retrieved October 30, 2020, used in QGIS. Image in Fig 1C from Microsoft Bing Image Tile of San Salvador Island, Bahamas (http://ecn.t3.tiles.virtualearth.net/tiles/a{q}.jpeg?g=1), downloaded through QGIS with image service provided by Microsoft (open source), retrieved October 31, 2020 and used in QGIS. No logos or trademarks were removed; annotations are by the authors.
Fig 2.
Pleistocene-Holocene stratigraphy of The Bahamas.
Stratigraphic position of trace fossil (TF) in this study indicated (arrow) toward top of Cockburn Town Member of Grotto Beach Formation, estimated age of 115 kya for the trace fossil. Stratigraphic terminology after [31,32], with Grotto Beach Formation bounded by paleosols, as indicated by red lines. Formation and member thicknesses not to scale.
Fig 3.
Outcrop of Cockburn Town Member (Grotto Beach Formation) eolianite at study site, San Salvador Island, The Bahamas.
(A) Middle portion of outcrop, with high-angle eolian cross-bedding partially disrupted by vertical and oblique root trace fossils and weathered rubble on top. Scale bar = 1 m. (B) Eastern portion of outcrop with stratigraphic position of protosol (P), interpreted fossil land-crab burrow (LCB) and trace fossil that is the main focus of this study (TF). Scale bar = 1 m.
Fig 4.
Plant and invertebrate trace fossils in Cockburn Town Member eolianite at study site, San Salvador Island, The Bahamas.
(A) Branching root trace fossils in high-angle cross-bedding. Photo scale in centimeters. (B) Close-up of root trace fossils. (C) Small vertical burrows (Skolithos) indicated by arrows, left expressed as external mold and right as full-relief internal mold. (D) Large vertical burrow (upper arrow) associated with root trace fossils, with thicker, spiraled portion in lowermost portion (lower arrow). Photo scale in centimeters.
Fig 5.
Fossil iguana nesting burrow, San Salvador Island, The Bahamas.
(A) Overall longitudinal view of structure, with protosol indicated (arrows). (B) Right-side oblique view. (C) Left-side oblique view. Scale in all photos in centimeters.
Fig 6.
Outline of fossil iguana nesting burrow with compacted zones.
(A) Full view of nesting burrow, with bas-relief expression on left and center, and low-relief expression in its bottom-right, cutting across and in front of surrounding cross-bedding. (B) Labeled outline of burrow with possible nest chamber (NC?) at base and compacted zones (CZ) indicated, indicated in order of probable formation by the tracemaker as it moved from bottom to top and back-filled burrow, CZ-1, CZ-2, and so on; arrow indicates direction of movement by tracemaker as it backfilled the burrow. Scale in centimeters.
Fig 7.
Boundary of fossil iguana burrow and root trace fossils.
(A) Left side burrow boundary showing diffuse, soft-sediment deformation of surrounding bedding and root trace fossils (inset). (B) Close-up of boundary with root trace fossils cutting across boundary (arrow). Scale in centimeters.
Fig 8.
Modern analogs of interpreted nesting environment and tracemaker for facies and trace fossil, respectively.
(A) Inland vegetated dune, mostly colonized by Coccoloba uvifera (sea grape) and composed of oolitic-skeletal sand, located about 120 m from intertidal zone at Sandy Point, San Salvador Island, The Bahamas. (B) Adult San Salvador rock iguana (Cylcura riyeli riyeli) in front of open dwelling burrow at Gerace Research Centre, San Salvador Island (The Bahamas).