Hexagonaria

{{distinguish|Hexagonia (disambiguation){{!}}Hexagonia}}

{{Automatic taxobox

| fossil_range=Devonian {{fossil range|416|359.2}}

| image = Hexagonaria percarinata close view.JPG

| image_caption = Hexagonaria percarinata

| taxon = Hexagonaria

| authority = Gürich, 1896

| subdivision_ranks = Species

| subdivision =

H. anna
H. cristata
H. fusiformis
H. percarinata
H. alpenensis
H. subcarinata
H. attenuate
H. potterensis
H. profunda
H. mirabilis

}}

Hexagonaria is a genus of colonial rugose coral. Fossils are found in rock formations dating to the Devonian period, about 350 million years ago. Specimens of Hexagonaria can be found in most of the rock formations of the Traverse Group in Michigan. Fossils of this genus form Petoskey stones, the state stone of Michigan.{{citation|last=Stumm|first=Erwin C.|date=19 June 1970|title=Corals of the Transverse Group of Michigan Part 13, Hexagonaria|publisher=The University of Michigan Press|volume=23|issue=5|pages=81–91|url=http://deepblue.lib.umich.edu/bitstream/2027.42/48447/2/ID296.pdf|format=PDF|location=Ann Arbor}} They can be seen and found in most Midwestern U.S. states.

Hexagonaria is a common constituent of the coral reefs exposed in Devonian Fossil Gorge below the Coralville Lake spillwayJean Prior, [http://www.igsb.uiowa.edu/browse/spillway/spillway.htm Devonian Fossil Gorge] {{Webarchive|url=https://web.archive.org/web/20100618043406/http://www.igsb.uiowa.edu/Browse/spillway/spillway.htm |date=2010-06-18 }}, Iowa Geological Survey, 1998. and in many exposures of the Coralville Formation in the vicinity of Coralville, Iowa.Brian J. Witzke and Bill J. Bunker, Sedimentation and stratigraphic architecture of a Middle Devonian (late Givetian) transgressive-regressive carbonate-evaporite cycle, Coralville Formation, Iowa area, [https://books.google.com/books?id=Ae0gmEK_jakC&pg=PA67 Paleozoic Sequence Stratigraphy, Biostratrigraphy and Biogeology, Special Paper 321], Geological Society of America, 1997.

Species Identification

Based on {{ill|Erwin C. Stumm|de|Erwin Charles Stumm}}'s Corals of the Traverse Group of Michigan Part 13, Hexagonaria, published in 1970. Notably, other species of Hexagonaria occur in rocks outside the Michigan Basin; those other species are not covered by the chart below and may overlap with the species below in size and numbers of septa. Other features diagnose the differences between species; the metrics below merely represent handy features for diagnosis in the Michigan Basin, not comprehensive diagnoses.

class="wikitable sortable sortable"

! scope="col"| Species

! scope="col"| Corallites (diameter)

! scope="col"| Septa (count)

H. anna

| 12–16 mm

| 32-44

H. cristata

| 16–20 mm

| 36-44

H. fusiformis

| 6–10 mm

| 34-38

H. percarinata

| ~10 mm

| 38-40

H. alpenensis

| 2–6 mm

| 26-28

H. subcarinata

| 8–12 mm

| 30-34

H. attenuate

| 8–14 mm

| 30-38

H. potterensis

| 4–15 mm

| 36-38

H. profunda

| 13–15 mm

| 38-42

Image Gallery

Image:Fossil Hexagonaria mirabilis MHNL.jpg|Hexagonaria mirabilis

Image:Unpolished Petoskey Stone (Photo by John Mortimore).jpg|H. percarinata, "Petoskey stone"

References

{{cite web|url=http://paleodb.geology.wisc.edu/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=5501&is_real_user=0 |archive-url=https://web.archive.org/web/20110720115534/http://paleodb.geology.wisc.edu/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=5501&is_real_user=0 |url-status=dead |archive-date=20 July 2011 |title=Hexagonaria |work=The Paleobiology Database |accessdate=27 February 2010 }}

Hexagonaria

Species Identification

Image Gallery

References

Further reading