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FIG. 2. Psammichnites plummeri and Psammichnites grumula. A. Holotype of Psammichnites plummeri. Note weathered specimen (center) displaying appar- ently widely separated, tangential, concave-up laminae of the internal backfill. Wayland Shale, Graham Formation, type locality of Fenton and Fenton (1937a), Texas, USA. TMM 35681. B. Detailed view of C, showing specimen of P. plummeri displaying wide marginal rim. GSA 2339-1. C. Slab showing the close as- sociation of P. plummeri and P. grumula. Note transition between ichnospecies and P. grumula emplaced at a slightly deeper level within the bed (center left). Kanawha Formation, Highway 199 outcrops, Kansas, USA. GSA 2339-1. D. Detailed view of C showing a specimen that displays a well-developed marginal fringe and Laminites-like backfill structure. GSA 2339-1. All specimens preserved in full relief on upper sandstone surfaces. Coin = 17.5 mm.

Figure 2 Psammichnites plummeri and Psammichnites grumula. A. Holotype of Psammichnites plummeri. Note weathered specimen (center) displaying appar- ently widely separated, tangential, concave-up laminae of the internal backfill. Wayland Shale, Graham Formation, type locality of Fenton and Fenton (1937a), Texas, USA. TMM 35681. B. Detailed view of C, showing specimen of P. plummeri displaying wide marginal rim. GSA 2339-1. C. Slab showing the close as- sociation of P. plummeri and P. grumula. Note transition between ichnospecies and P. grumula emplaced at a slightly deeper level within the bed (center left). Kanawha Formation, Highway 199 outcrops, Kansas, USA. GSA 2339-1. D. Detailed view of C showing a specimen that displays a well-developed marginal fringe and Laminites-like backfill structure. GSA 2339-1. All specimens preserved in full relief on upper sandstone surfaces. Coin = 17.5 mm.

Related Figures (8)

FIG. 1. Psammichnites plummeri. A. Presence of distinct dorsal ridge, fine crenulated transverse ridges, slightly wavy contour of trail. Fountain Formation, Section 9B of Maples and Suttner (1990), Colorado USA. KUMIP 230319. Scale bar = 1 cm. B. Preservational variant with dorsal groove and faint transverse ridges locally present. Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C-1-97. Scale bar = 1 cm. C. Preferential distribution with longitudinal axis parallel to ripple crests. Also not association with P. implexus (lower left) crowded on ripple crests and slopes. Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C-2-97. All specimens preserved in full relief on upper sandstone surfaces.
FIG. 1. Psammichnites plummeri. A. Presence of distinct dorsal ridge, fine crenulated transverse ridges, slightly wavy contour of trail. Fountain Formation, Section 9B of Maples and Suttner (1990), Colorado USA. KUMIP 230319. Scale bar = 1 cm. B. Preservational variant with dorsal groove and faint transverse ridges locally present. Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C-1-97. Scale bar = 1 cm. C. Preferential distribution with longitudinal axis parallel to ripple crests. Also not association with P. implexus (lower left) crowded on ripple crests and slopes. Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C-2-97. All specimens preserved in full relief on upper sandstone surfaces.
FIG. 3. Cross-sectional variability of Psammichnites plummeri and Psam- michnites grumula. A. Compressed specimen displaying elliptical section, flat trilobate basal surface and angular dorsal ridge. B. Compressed specimen dis- playing elliptical section, flat bilobate basal surface and dorsal groove. C. Specimen exhibiting subtriangular section, pronounced bilobate basal surface and poorly differentiated dorsal ridge. D. Uncompressed specimen showing subcircular section, unilobate base and well-defined angular dorsal ridge.
FIG. 3. Cross-sectional variability of Psammichnites plummeri and Psam- michnites grumula. A. Compressed specimen displaying elliptical section, flat trilobate basal surface and angular dorsal ridge. B. Compressed specimen dis- playing elliptical section, flat bilobate basal surface and dorsal groove. C. Specimen exhibiting subtriangular section, pronounced bilobate basal surface and poorly differentiated dorsal ridge. D. Uncompressed specimen showing subcircular section, unilobate base and well-defined angular dorsal ridge.
FIG. 4. Psammichnites plummeri. “Crossopodia” specimens from the Carboniferous of England. A. Specimen showing the typical morphology of a phobo- tactic meander. Grit Beds, Wick-in-Abson, England. BMNH A 1203. Scale bar = 1 cm. B. Specimen showing well-defined median dorsal ridge and tight, fine transversal ridges diagnostic of P. plummeri. Coal Measures, Polbroe Burn, England. BMNH T 283. Scale bar = 1 cm. Psammichnites plummeri may display different preserva- tional variants. The dorsal structure is interpreted as recording the movement of the siphon through the sediment, and its preservational expressions are interpreted as a taphonomic arti-
FIG. 4. Psammichnites plummeri. “Crossopodia” specimens from the Carboniferous of England. A. Specimen showing the typical morphology of a phobo- tactic meander. Grit Beds, Wick-in-Abson, England. BMNH A 1203. Scale bar = 1 cm. B. Specimen showing well-defined median dorsal ridge and tight, fine transversal ridges diagnostic of P. plummeri. Coal Measures, Polbroe Burn, England. BMNH T 283. Scale bar = 1 cm. Psammichnites plummeri may display different preserva- tional variants. The dorsal structure is interpreted as recording the movement of the siphon through the sediment, and its preservational expressions are interpreted as a taphonomic arti-
FIG. 5. Psammichnites grumula. A. Hypichnial preservation of upper surface of the trace with equidistant holes; a few holes are filled with sediment. Note marginal fringe represented by lateral levees and arcuate marks suggestive of the internal meniscate structures. Stull Shale Member, Kanwaka Shale Formation, Waverly trace fossil site, Kansas, USA. KUMIP 288506. Scale bar = | cm. B. Hypichnial preservation showing partially filled-in trace (right). Possible resting structure (central right) and poorly developed details of ventral surface (lower left). Stull Shale Member, Kanwaka Shale Formation, Waverly trace fossil site, Kansas, USA. KUMIP 288506. Scale bar = 1 cm. C. Full relief preservation at the top of sandstone. Irregular distribution on rippled-top bed, dorsal protruding mounds and locally visible median ridge. Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C-1—97. D. Detail of C showing uneven spacing between mounds, dorsal groove and elliptical cross-section (upper left). Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C- 1-97.
FIG. 5. Psammichnites grumula. A. Hypichnial preservation of upper surface of the trace with equidistant holes; a few holes are filled with sediment. Note marginal fringe represented by lateral levees and arcuate marks suggestive of the internal meniscate structures. Stull Shale Member, Kanwaka Shale Formation, Waverly trace fossil site, Kansas, USA. KUMIP 288506. Scale bar = | cm. B. Hypichnial preservation showing partially filled-in trace (right). Possible resting structure (central right) and poorly developed details of ventral surface (lower left). Stull Shale Member, Kanwaka Shale Formation, Waverly trace fossil site, Kansas, USA. KUMIP 288506. Scale bar = 1 cm. C. Full relief preservation at the top of sandstone. Irregular distribution on rippled-top bed, dorsal protruding mounds and locally visible median ridge. Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C-1—97. D. Detail of C showing uneven spacing between mounds, dorsal groove and elliptical cross-section (upper left). Douglas Group, Highway 166 outcrops, Kansas, USA. DG-C- 1-97.
FIG. 6. Psammichnites grumula. A. Specimen displaying an unspecialized curly pattern with self-overcrossing. Note the slightly irregular distance betweer consecutive dorsal holes and the local presence of a median groove. Parkwood Formation, Interstate Highway 459 outcrops, Alabama, USA. Field specimen Coin = 17.5 mm. B. Detail of A showing area of self-overcrossing. Note the presence of a distinct marginal fringe and internal backfill structure.
FIG. 6. Psammichnites grumula. A. Specimen displaying an unspecialized curly pattern with self-overcrossing. Note the slightly irregular distance betweer consecutive dorsal holes and the local presence of a median groove. Parkwood Formation, Interstate Highway 459 outcrops, Alabama, USA. Field specimen Coin = 17.5 mm. B. Detail of A showing area of self-overcrossing. Note the presence of a distinct marginal fringe and internal backfill structure.
FIG. 7. Psammichnites grumula. Specimen showing unique elongate dorsal holes. Coal Formation, Haltwhistle, England. OUMNH E.5033. Scale bar = | cm.
FIG. 7. Psammichnites grumula. Specimen showing unique elongate dorsal holes. Coal Formation, Haltwhistle, England. OUMNH E.5033. Scale bar = | cm.
FIG. 8. Psammichnites implexus. A. Specimen displaying meandering tendency, but exhibiting self-overcrossing. Pottsville Formation, Alabama, USA. Holo- type (GSATC 236). B. Specimens associated with tear-shaped resting structures. Pride Mountain Formation, Alabama, USA. GSATC 241. C. Specimen in ripple trough displaying guided meandering. Stull Shale Member, Kansas, USA. KUMIP 288507. D. Specimen exhibiting guided meandering tendency cross-cutting another specimen. Pottsville Formation, Alabama, USA. Paratype. GSATC 238. E. Differential preservation of the dorsal ridge on ripple crest, the trace outline is hardly visible. Pottsville Formation, Alabama, USA. Paratype. GSATC 240. F. Scribbling pattern resulting from self-overcrossing and overlapping among spec- imens. Differential preservation of the dorsal ridge on top of the ripple also observable. Pottsville Formation, Alabama, USA. Paratype. GSATC 241. All speci- mens preserved in full relief on upper sandstone surface. Bar scale = 1 cm.
FIG. 8. Psammichnites implexus. A. Specimen displaying meandering tendency, but exhibiting self-overcrossing. Pottsville Formation, Alabama, USA. Holo- type (GSATC 236). B. Specimens associated with tear-shaped resting structures. Pride Mountain Formation, Alabama, USA. GSATC 241. C. Specimen in ripple trough displaying guided meandering. Stull Shale Member, Kansas, USA. KUMIP 288507. D. Specimen exhibiting guided meandering tendency cross-cutting another specimen. Pottsville Formation, Alabama, USA. Paratype. GSATC 238. E. Differential preservation of the dorsal ridge on ripple crest, the trace outline is hardly visible. Pottsville Formation, Alabama, USA. Paratype. GSATC 240. F. Scribbling pattern resulting from self-overcrossing and overlapping among spec- imens. Differential preservation of the dorsal ridge on top of the ripple also observable. Pottsville Formation, Alabama, USA. Paratype. GSATC 241. All speci- mens preserved in full relief on upper sandstone surface. Bar scale = 1 cm.
Related topics:
Invertebrate IchnologyCarboniferous Palaeoecologygeology of AlabamaTidal FlatSediment-Water Interface
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