Wooster’s Fossils of the Week: Sponge and clam borings that revealed an ancient climate event (Upper Pleistocene of The Bahamas)

April 28th, 2017

This week’s fossils celebrate the publication today of a paper in Nature Geoscience that has been 20 years in the making. The title is: “Sea-level oscillations during the Last Interglacial highstand recorded by Bahamas coral”, and the senior author is the geochronological wizard Bill Thompson (Woods Hole Oceanographic Institution). The junior authors are my Smith College geologist friends Al Curran and Brian White and me.

The paper’s thesis is best told with an explanation of this 2006 image:
This photograph was taken on the island of Great Inagua along the coast. The flat dark surface in the foreground is the top of a fossil coral reef (“Reef I”) formed during the Last Interglacial (LIG) about 123,000 years ago. It was eroded down to this flat surface when sea-level dropped, exposing the reef to waves and eventually terrestrial weathering. The student sitting on this surface is Emily Ann Griffin (’07), one of three I.S. students who helped with parts of this project. (The others were Allison Cornett (’00) and Ann Steward (’07).) Behind Emily Ann is a coral accumulation of a reef (“Reef II”) that grew on the eroded surface after sea-level rose again about 119,000 years ago. These two reefs show, then, that sea-level dropped for about 4000 years, eroding the first reef, and then rose again to its previous level, allowing the second reef to grow. (You can see an unlabeled version of the photograph here.) The photograph at the top of this post is a small version of the same surface.

The significance of this set of reefs is that the erosion surface separating them can be seen throughout the world as evidence of a rapid global sea-level event during the Last Interglacial. Because the LIG had warm climatic conditions similar to what we will likely experience in the near future, it is crucial to know how something as important as sea-level may respond. The only way sea-level can fluctuate like this is if glacial ice volume changes, meaning there must have been an interval of global cooling (producing greater glacial ice volume) that lowered sea-level about 123,000 years ago, and then global warming (melting the ice) that raised it again within 4000 years. As we write in the paper, “This is of great scientific and societal interest because the LIG has often been cited as an analogue for future sea-level change. Estimates of LIG sea-level change, which took place in a world warmer than that of today, are crucial for estimates of future rates of rise under IPCC warming scenarios.” With our evidence we can show a magnitude and timing of an ancient sea-level fluctuation due to climate change.

Much of the paper concerns the dating techniques and issues (which is why Bill Thompson, the essential geochronologist, is the primary author). It is the dating of the corals that makes the story globally useful and significant. Here, though, I want to tell how the surface was discovered in the first place. It is a paleontological tale.

In the summer of 1991 I worked with Al Curran and Brian White on San Salvador Island in The Bahamas. They were concentrating on watery tasks that involved scuba diving, boats and the like, while I stayed on dry land (my preferred environment by far). I explored a famous fossil coral exposure called the Cockburntown Reef (Upper Pleistocene, Eemian) that Brian and Al had carefully mapped out over the past decade. The Bahamian government had recently authorized a new harbor on that part of the coastline and a large section of the fossil reef was dynamited away. The Cockburntown Reef now had a very fresh exposure in the new excavation quite different from the blackened part of the old reef we were used to. Immediately visible was a horizontal surface running through the reef marked by large clam borings called Gastrochaenolites (see below) and small borings (Entobia) made by clionaid sponges (see the image at the top of this post).
Inside the borings were long narrow bivalve shells belonging to the species Coralliophaga coralliophaga (which means “coral eater”; see below) and remnants of an ancient terrestrial soil (a paleosol). This surface was clearly a wave-cut platform later buried under a tropical soil.

My colleagues and I could trace this surface into the old, undynamited part of the Cockburntown Reef, then to other Eemian reefs on San Salvador, and then to other Bahamian islands like Great Inagua in the far south. Eventually this proved to be a global erosion surface described or at least mentioned in many papers, but its significance as an indicator of rapid eustatic sea-level fall and rise was heretofore unrecognized. Finally getting uranium-thorium radioactive dates on the corals above and below the erosion surface placed this surface in a time framework and ultimately as part of the history of global climate change.

This project began 25 years ago with the discovery of small holes left in an eroded surface by humble sponges and clams. Another example of the practical value of paleontology.


Thompson, W.G., Curran, H.A., Wilson, M.A. and White, B. 2011. Sea-level oscillations during the Last Interglacial highstand recorded by Bahamas coral. Nature Geoscience (DOI: 10.1038/NGEO1253).

White, B.H., Curran, H.A. and Wilson, M.A. 1998. Bahamian coral reefs yield evidence of a brief sea-level lowstand during the last interglacial. Carbonates and Evaporites 13: 10-22.

Wilson, M.A., Curran, H.A. and White, B. 1998. Paleontological evidence of a brief global sea-level event during the last interglacial. Lethaia 31: 241-250.

[Originally posted September 11, 2011. Some updates and editing.]

Wooster’s Fossil of the Week: A juvenile conch from the Upper Pleistocene (Eemian) of The Bahamas

November 18th, 2016

inagua-lobatus-gigasI collected this beautiful shell from a seashore exposure of Pleistocene sediments on Great Inagua, the third largest island of The Bahamas. I was on an epic expedition to this bit of paradise with Al Curran and Brian White of Smith College in March 2006. We were pursuing evidence for a sea-level change event in the Eemian, about 125,000 years ago. This was some of the most exciting scientific work I’ve done, so this little shell brings back many memories. I found it loosely cemented into a small patch of carbonate sediments inside a hollow of an ancient coral reef. This shell and numerous other samples were basic data for a rapid rise and fall of sea level during the last interglacial interval. The project is summarized in the Thompson et al. (2011) reference below.

This is a juvenile of the common Queen Conch Lobatus gigas (Linnaeus, 1758). In its adult form with a flared aperture it is one of the most recognizable modern shells in the world. Some of you may be surprised by the generic name. I was. I knew this shell as Strombus gigas, the original name given to it by the sainted father of taxonomy Carolus Linnaeus in 1758. After several adventures in the literature, Landau et al. (2008) placed the species in the genus Lobatus Swainson 1837.

salvador-lobatus-gigas-1The species looks exactly the same today, at least in its shell. This is a similar modern Queen Conch juvenile collected from San Salvador Island in The Bahamas. Note the color patterns which are lost in the fossil.

salvador-lobatus-gigas-2This is the apertural view of the same modern shell. With time it would have grown a much thicker apertural margin to protect it from predators.

buonanni-strombus-gigas-figureThis is the earliest image known of the Queen Conch (Buonanni, 1684). For a long time the type specimen (the specimen of record defining the taxon) of Strombus gigas (the older Linnaeus name) was missing. In 1941 this figure — the figure itself — was designated a neotype (a replacement type) of the species. (First time I’ve heard of that move.) The original type specimen, though, was found in Sweden in 1953, so there is an actual shell in the collections and no need for this neotype.

bonanno-coverThat first figure of Lobatus gigas was drawn by Filippo Bonanni (1638-1723), a remarkable Italian Jesuit scholar. It is found in the book above, which is the first known guide to seashells for collectors. (Note the “SUPERIORUM PERMISSU”, meaning he published with the permission of his Jesuit superiors.) Bonanni was one of the first to suggest fossils had at least some organic origins, speculating that they were either organism remains or “products of natural powers.”


Buonanni, F. 1684. Recreatio mentis, et oculi in observatione animalium testaceorum curiosis naturae inspectoribus italico sermone primum proposita. p. Philippo Bonanno . Nunc denuo ab eodem latine oblata, centum additis testaceorum iconibus, circaquae varia problemata proponuntur. Ex typographia Varesij, Romae, xvi + 270 + [10] pp., 139 pls.

Landau, B.M., Kronenberg G.C. and Herbert, G.S. 2008. A large new species of Lobatus (Gastropoda: Strombidae) from the Neogene of the Dominican Republic, with notes on the genus. The Veliger 50: 31–38.

Thompson, W.G., Curran, H.A., Wilson, M.A. and White, B. 2011. Sea-level oscillations during the Last Interglacial highstand recorded by Bahamas corals. Nature Geoscience 4: 684–687.

White, B.H., Curran, H.A. and Wilson, M.A. 2001. A sea-level lowstand (Devil’s Point Event) recorded in Bahamian reefs: comparison with other Last Interglacial climate proxies; In: Greenstein, B.J. and Carney, C., (editors), Proceedings of the 10th Symposium on the Geology of the Bahamas: Bahamian Field Station, San Salvador Island, p. 109-128.

Wilson, M.A., Curran, H.A. and White, B. 1998. Paleontological evidence of a brief global sea-level event during the last interglacial. Lethaia 31: 241-250.

What we learned in Climate Change (Geology 210, Spring 2016)

May 31st, 2016


A dedicated group of geologists, physicists, archaeologists, political scientists, biologists, english and history majors joined forces to learn a bit about Climate Change in the natural laboratory of Northeast Ohio. Here they surround a glacial erratic in Secrest Arboretum of the OARDC – where The Ohio State University and the National Weather Service has meteorological records extending back to the late 1800s CE. The Arboretum also has an extensive collection of stands of trees from around the world that are used in our climate studies below (special thanks to Joe Cochran (OSU) for permission to work at Secrest).

The first project: the glacial transition in a sediment core from  Browns Lake Bog


Dr. Thomas Lowell gives the rundown at Browns Lake Bog – Tom is a professor at the University of Cincinnati and long-time collaborator and the core boss.


Initial description of the 5 meter core – we obtained two radiocarbon ages, measured magnetic susceptibility, loss on ignition, in addition to core description and sediment analyses.

The Upshot of the Lake Work – The two ages were chosen at transitions in the character of the peat and mineral matter – we identified a major shift at the time of the Bolling – Allerod warming and at the cooling of the Younger Dryas.  The abrupt climate changes (ACCs) and discussion of how the world moves from the Pleistocene to the Holocene is brought home to Ohio in this core (Figure below). It is exciting to explore how these ACCs affected NE-Ohio’s ecosystems and physical landscapes.


Project 2: Tree Ring Dating of the Biggio Barn


The barn owner gives the rundown on the history and possible ages of the hand hewn timber frame. The dating of the barn project introduced the class to the science of tree-rings.


Hong Kong dendrochronologist, Vincent shows the class how by standing on two milk crates he cores a beam – the instructor adds a stabilizing foot to Vincent’s precarious sampling strategy.

The upshot of Barn Dating: Ten of the beams from the Biggio Barn were cut in the spring of 1840 CE. The building then was likely constructed shortly after that cut date.  A copy of the report to the owner from the class can be found here. The ring-width data obtained in this study are used in drought studies below. The Wooster Tree Ring lab has dated over 60 barns and houses in Ohio and PA (this video describes the process and some of the science).

Project 3a: Extracting a Temperature Proxy Record from Larch in Kamchatka
Vincent Hui, Abbey Martin, Sarah McGrath, Matthew Shearer, Ann Wilkinson

The purpose of this study was to analyze Kamchatka larch (Larix cajandery Mayr.) tree ring widths from Fareast, Russia. The team standardized the chronology using two methods, (1)  negative exponential, and (2) regional curve standardization (RCS), and they then compared how the standardization technique influenced correlations. Both standardized series were correlated with meteorological records showing high positive correlations for summer temperatures. The RCS showed stronger correlations and was used for NTREND comparison, temperature reconstruction, and spectral analysis. Together these correlations and comparisons showed the larch primarily responds to summer temperature and can be used to reconstruct summer temperatures.


The Kamchatka team of researchers (without Vincent) who did the study. They are posing at Wooster Memorial Park where a recent planting of 700 trees and prairie will sequester more carbon in the future than the previous agricultural land use at the site.


1 – The Kamchatka larch tree-ring widths are most sensitive to summer (May through September) temperatures.

2 – The team recommends the region curve standardization method) RCS method for standardization with a sample size of 190 series.

3 – The RCS series showed similar trends as the NTREND series, suggesting the Kamchatka site follows the same trends as much of the northern hemisphere.

4 – Ring-widths show a general increase in temperature over the last 350 years for the interior of Kamchatka. This is unprecedented over the past 300 years and is consistent with other proxies such as glaciers.

Project 3b: Past climate inferences using data from Johnson Woods
 Sharron Osterman, Annette Hilton, Cameron Steckbeck, Gina Malfatti, Amineh AlBashair

  • tst
  • The Johnson Woods team assembled a newly compiled data set originally sampled in 1985 by Dr. Ed Cook (LDEO), by the Wooster Tree Ring Lab in 2003 and most recently updated by Dr. Justin Maxwell (Indiana State University). They found there was a marked release in the tree ring record across northern Ohio about the time of European Settlement in the region. This may be in part due to the disturbance in the record, however it could also persist due to the positive response that tree growth has to summer precipitation.
  • Slide2
  • Slide1Above is a histogram showing the correlations of the Johnson Woods ring-width series and monthly precipitation and temperature records from the OARDC spanning 1880 to 2014 CE. The trees are a record of summer precipitation (positive correlation) and favor wet summers. These trees are negatively correlated with high summer temperatures.

One Question on the final exam:
What is the Climate response of European Larch to climate of Ohio – Secrest Arboretum (and why might this exploration be relevant?).

  • coring1

Obtaining high quality cores for ring-width chronologies from European Larch at Secrest Arboretum.


 The upshot here is the ring-width chronology below. The class worked on this as part of the final exam and found that similar to the oaks in the region, the European Larch is sensitive to summer precipitation and is stressed by high summer temperatures. The tailing off of the ring-widths during recent decades could be the result of warmer summer temperatures – a hypothesis that needs testing. The relevance of this study is that as climate changes in the high latitudes of Europe and Asia, where these larch dominate – it may be the case, that warming may stress the species leading to decreases in bioproductivity – these ideas need further work to test if this is a viable hypothesis.

Plot 1


A day in Johnson Woods – the full class in the rain.


danWe also learned that Dan Misinay (’16) is a pretty fair teaching assistant.


The class wanders around the gas power plant on the Wooster campus – three years ago the college transitioned from coal burning to natural gas – the carbon dioxide emissions on campus have been cut in half. However, now the College buys its power for cooling (air conditioning) off campus from the grid, where much of the electricity is powered by coal, but with a growing portfolio of clean energy sources (special thanks to Lanny Whitaker who showed us the plant and explained where our energy comes from – thank you). We also thank Nick Wiesenberg (our able Geology Technician) for his knowledge of trees, barn dating and general troubleshooting,  Tom Lowell and his students for the high quality sediment cores, our TA Dan and a host of tree-ring scientists who contributed data to our efforts in this course. Special thanks too – to the Secrest Arboretum. A portion of the Kamchatka tree-ring record was supported by NSF- AGS – 1202218.

A Wooster Geologist Visits Spangler Park

May 9th, 2016

Chloe1Editor’s note: The following entry was written by Chloe Wallace (’17), a student in this year’s Sedimentology & Stratigraphy course. One of our writing assignments was to write a blog post about our recent field trip to Spangler Park (also known as Wooster Memorial Park). I told the class that I would publish on this site the best entry, and Chloe won. It was a very close contest, though, with many other excellent entries. All the following words and images are Chloe’s.

Wooster, Ohio— On April 23, 2016, the Sedimentology and Stratigraphy class took a field trip to the local Wooster Memorial Park, also called Spangler Park. The goal was to study three separate outcrops, and then do a little exploring of our own.

The first stop was a short walk from the entrance to the park, specifically at 40.81475° North and 82.02383° West (above).

This outcrop contains rocks from the Logan Formation of the Lower Carboniferous. The rocks were non-laminated and of silt size, so it is made of siltstone. There are signs of a little bit of oxidation. There are also ripples present on some of the rocks, which is evidence of a shallow water environment. There were gray shale clasts within the siltstone, which were most likely deposited by storm events. The fact that some of the beds are thicker than others is more evidence of storm events because more sediment would have been deposited during storms and thinner beds would have built up during times of less activity. The bedding angles vary throughout the outcrop, also known as cross-stratification, which is more evidence that ripples and dunes were present as part of a flow regime at the time of deposition.

Chloe2Burrow fossils, which are a form of trace fossil, were left behind by deposit feeding organisms on some of the rocks. This is more evidence of a shallow, marine environment. Based on all the sedimentary structures and characteristics found at this outcrop, these rocks were deposited on the shallow shelf, below the fair weather wave base and above the storm wave base.

The Logan Formation is made up of five members, but specifically the Byer member is likely exposed here. Layers of fine sandstone and siltstones with shale sometimes inter-bedded characterize the Byer member (Hunt, 2009). Although it isn’t present in the two photos above, another member is usually deposited right below the Byer Member. It is called the Berne Member and it is composed of molasse rock, which is a quartz-rich conglomerate formed when the eroded material from continental collisions gathers in a foreland basin. In this case it is eroded material from the continental collisions that built up the Appalachians. The eroded material was then deposited to the west in the foreland basin that covers Pennsylvania and Ohio.

The second outcrop we reached was at the bottom of a gorge, along Rathburn Run, specifically at 40.81784° N and 82.02946° W. The exposure was composed of laminated grey shale from the Cuyahoga Formation. It marked a formation boundary because Logan Formation sandstone lies directly above it. This means the grey shale is older than the Logan Formation. Similar to the Logan Formation, there are trace fossils of marine burrowing organisms within the shale.

Chloe3In the above picture you can see an East-West trending joint running through the center of the Cuyahoga Formation grey shale caused by tectonic faulting, which is a phenomenon unrelated to the sedimentary structures.

Chloe4Siderite deposits were also found in some sandstone at the Rathburn run outcrop, which form after deposition, a diagenetic property. Siderite forms in anoxic environments where iron is reduced and sulfur is present. The grey shale of the Cuyahoga Formation isn’t porous enough for siderite replacement to take place, but the sandstone is.

The third outcrop was father upstream along on a cut bank, located at 40.81903° N and 82.02953° W.

Chloe5This photo is taken from across Rathburn Run, from the point bar. This outcrop is much younger in age, from the last time Ohio was affected by glaciation. During the Last Glacial Maximum, specifically the Pleistocene, glacial debris flows deposited the bottom section of the outcrop. The sediment is characterized by a fining upwards sequence and has two scales of support. Some areas of the deposit are composed of large grains within a matrix-support due to debris flow. Other areas of the deposit are composed of sandy conglomerate rock that is grain supported. Overall the sediment is poorly sorted and contains glacial erratics within the sediment, including boulders made of gneiss, granite, and some sedimentary rocks.

A channel cut through the original glacial debris flow deposit and was eventually filled in by wind-blown silt, also known as loess. Loess is characteristically different from the glacial deposit at the bottom of the outcrop. Loess breaks in sheets, which causes it to have steep angles. Overall, the history of this outcrop is that approximately 15,000 years ago debris flow events deposited the glacial sediment at the bottom of the outcrop, then a channel cut into the deposit and that channel eventually filled with eolian (wind-blown) silt.

Chloe6After venturing a little on our own, a few other students and myself came across a fourth outcrop that was from the Logan Formation at an elevation above both the Cuyahoga Formation shales and the glacial deposits. There is more evidence of jointing and cross-stratification that can be seen in the picture.

We saw two separate formations from the Lower Carboniferous during the field trip. We also were able to see another type of sedimentary deposit that was glacial and eolian in origin. Spangler Park displays and exposes a variety of sedimentary structures and sedimentary characteristics. The park can be characterized as displaying a coarsening upwards sequence with the Cuyahoga shale at the bottom, followed by the coarser siltstone and sandstone of the Logan Formation. This kind of coarsening upwards is usually evidence of either regression or progradation.

Both the Logan and Cuyahoga Formations are representative of shallow marine environments, as was seen in the evidence found at Spangler. Further research shows that the Cuyahoga Formation was deposited as part of a marine environment where the shoreline was prograding during the Kinderhookian and possibly very early Osagean (Bork and Malcuit, 1979; Matchen and Kammer, 2006). The Logan Formation followed and was deposited within a marine proximal deltaic environment during the Osagean (Hunt, 2009; Matchen and Kammer, 2006). This explains the coarsening upwards sequence and the marine sedimentary structures and fossils seen throughout the field trip.


Bork, K.B., and Malcuit, R., 1979, Paleoenvironments of the Cuyahoga and Logan Formations (Mississippian) of central Ohio: Geological Society of America Bulletin II, v. 90, p. 1782-1838.

Hunt, H., 2009, Paleocommunities and Paleoenvironments of the Logan Formation (Mississippian, Osagean) of northeastern Ohio [Undergraduate thesis]: Wooster, The College of Wooster, 50 p.

Matchen, D.L., and Kammer, T.W., 2006, Incised valley fill interpretation for Mississippian Black Hand Sandstone, Appalachian Basin, USA: Implications for glacial eustasy at Kinderhookian-Osagean (Tn2-Tn3) boundary: Sedimentary Geology, v. 191, 89-113.

A geological obstacle course in Ada Canyon, southern Israel

March 19th, 2016

1 Ada canyon startMITZPE RAMON, ISRAEL — As part of our Shabbat trip today, Yoav Avni wanted to take me up Ada Canyon (N30.32973°, E34.91417°) to explore the Hazeva (Miocene) and Arava (Pleistocene). He cryptically said, “There will be places we can barely get through”. True, that. Above is Yoav at the start of the hike. Turns out this is a slot canyon with challenges.

2 Arava narrows begin“The narrow part begins”, he says helpfully.

3 Narrowing AravaAt this point I have to take off my pack to reduce my sideways width.

4 Narrow AravaAnd sideways with a twist is the only way through as the walls close in. Pro tip: Never do this when it is raining.

5 Problematic Arava sectionNow it gets problematic with boulder scrambling and claustrophobia.

6 First ladder aravaA ladder! I never did mention my aching shoulder.

7 Second ladder AravaSteps cut in the rock and then a second ladder. Going down is always easier than going up, right?

8 Rope climb AravaA knotted rope to climb the cliff! Note the shadow of successful me at the top of the last obstacle. Wondering, though, what these climbs are like on the way back.

9 Ada view 031916The view at the top of the mountain, though, really was spectacular. This is a view towards Be’er Ada, with the fault described in the previous post running diagonally across the background.

10 Hazeva cobbles 585And yes, the geology along the way! It was very impressive. The Hazeva Formation is mostly sandstone with some layers of sandy conglomerate as in the above image. It was deposited in a wetlands with occasional floods (which produced the coarse layers). The cobbles are rounded cherts derived from Jordan to the east.

11 Arava faciesThe Arava Formation was deposited in a desert much like what we see today. It is interbedded gravels (from wadis) and unconsolidated silts (from playas and saline lakes). Classic sed/strat material. It was all well worth the adventure for this aging geologist!


A Shabbat trip to Be’er Ada in the southern Negev

March 19th, 2016

1 Road to Beer AdaMITZPE RAMON, ISRAEL — Yoav Avni and I have a tradition on Shabbat. We drive somewhere to explore interesting geology and history unconnected to current projects. It’s not really work — it’s geotourism. We are, though, always talking about new ideas. Today we traveled south of Mitzpe Ramon into the “deep desert” of the Arava below the Negev Highlands.

2 MR view to JordanThe morning view south across Makhtesh Ramon was spectacular. It isn’t conveyed very well through an image only 585 pixels wide, but it is a perspective of unusual clarity. The purple streak at the top represents mountains in western Jordan. The haze just below them is in the Arava Valley. We are looking across most of the Negev.

3 Acacia grove Beer AdaOur mission today was to visit Be’er Ada (Bir Abu ‘Auda), an historic well, and the geology around it. (N30.32229°, E34.90701°, if you’re following at home.) The top image on this post is a view from the road to the well. Just above is a grove of acacia trees near the well. The abundance of these trees, and their good health, is an indication of accessible water.

4 Yoav at Beer AdaHere is Yoav peering down into Be’er Ada. (“Be’er” means well.) It is at least twenty meters deep. The base is filled with silt, so it will have to be dug out to supply water again. This well is thousands of years old and has been a critical watering spot in the Negev for traveling groups. The next nearest well is to the east about 40 km away. Another 40 km or so to the west is another well. Be’er Ada was active as late as the 1950s, and likely had sporadic use afterwards. The water here accumulates on the impermeable clays of the Taqiya Formation (Paleocene).

5 Acacia outcrop view 031916This is a view from near Be’er Ada to the main geological interest for me: the the orangish Hazeva Formation (Miocene) topped unconformably by the gray Pleistocene Arava Formation. We will spend much more intimate time with these units in the next post. Note the graceful acacia trees.

6 Beer Ada faultThis area is next to a complex fault system. On the left is a down-dropped block of Hazeva and Arava, with Cretaceous rocks on the right. The fault is also part of the reason for the subterranean water resources at Be’er Ada.

7 Ada profileIn the middle of the image is an example of the pareidolia so common in stark landscapes. Some people see a face in profile. Apparently tour guides like to call this the head of “Ada” for whom the well was named. However, there never was such a woman!

Note the excellent weather in these images. A perfect Negev day! Thank you to Yoav for being such a generous host.

Wooster’s Fossil of the Week: A Pleistocene octocoral holdfast from Sicily

February 6th, 2015

OctocoralHoldfastPleistoceneSicilyMy Italian colleague Agostina Vertino collected this beautiful specimen from the Pleistocene of Sicily and brought it to Wooster when she visited five years ago. It is the attaching base (holdfast) of the octocoral Keratoisis peloritana (Sequenza 1864). Octocorals (Subclass Octocorallia of the Class Anthozoa) are sometimes called “soft corals” because of their organic-rich, flexible skeletons. They are distinguished by polyps with eight tentacles, each of which is pinnate (feathery). Octocorals include beautiful sea fans and sea whips that require a hard substrate for stability. This particular holdfast is on a small slab of limestone.

The genus Keratoisis is known as the “bamboo coral” because it looks jointed like stalks of the plant. I collected fragments of Pleistocene Keratoisis branches during my visit to Sicily last year.
Giuseppe SeguenzaGiuseppe Seguenza (1833-1889) named the species Keratoisis peloritana. He was a Sicilian natural historian with broad interests, especially in geology. Although educated as a pharmacist, he found geology much more exciting on the volcanically active islands of the Mediterranean. He eventually became a professor of geology at the University of Messina (where the bust of him shown above resides). Italian sources say Seguenza received the famous Wollaston Medal from the Geological Society of London, but that does not appear to be true. Instead it appears that he was given “the balance of the proceeds of the Wollaston Fund” as a donation at the time the medal was awarded to Thomas Huxley (in 1876). The records of the society say that “the stipend of an Italian professor was too small to enable him to prosecute his palaeontological researches as fully as he could desire” (Woodward, 1876). Giuseppe Seguenza died in Messina at 56 years old.


Di Geronimo, I., Messina, C., Rosso, A., Sanfilippo, R., Sciuto, F., and Vertino, A. 2005. Enhanced biodiversity in the deep: Early Pleistocene coral communities from southern Italy. In: Cold-Water Corals and Ecosystems, p. 61-86. Springer: Berlin, Heidelberg.

Fois, E. 1990. Stratigraphy and palaeogeography of the Capo Milazzo area (NE Sicily, Italy): clues to the evolution of the southern margin of the Tyrrhenian Basin during the Neogene. Palaeogeography, Palaeoclimatology, Palaeoecology 78: 87-108.

Langer M. 1989. The holdfast internodes and sclerites of Keratoisis melitensis Goldfuss 1826 Octocorallia in the Pliocene foraminifera marl Trubi of Milazzo Sicily Italy. Palaeontologische Zeitschrift 63: 15-24.

Woodward, H. 1876. Reports and proceedings, Geological Society of London. Geological Magazine 13: 181-182.

Wooster’s Fossil of the Week: Glyptodon carapace fragment from the Pleistocene

December 29th, 2013

Glyptodon carapace fragment Pleistocene 585This is a tiny bit of a large and fascinating Pleistocene animal from Central and South America. It is Glyptodon, an impressively large mammal with bony armor much like its cousin the armadillo. The above fossil is a fragment of that carapace. Each roundel is called a scute.
Glyptodon carapace side 585This is a side view of the above carapace fragment showing its thickness and layered, bony nature.
Glyptodon ReconstructionThis modern reconstruction of Glyptodon (from Wikipedia with a GNU free documentation license) shows its primary features, including the bony shell (the size and shape of a Volkswagen Beatle, as is often stated) and its characteristically large claws. It belongs to the Superorder Xenarthra, which includes armadillos, sloths and anteaters. I see the resemblance. They could not completely go turtle, as it were, but it could pull its head back enough into the shell that the scutes on the top of the skull would protect it like a cap. They had massive jaws and flat grinding teeth typical of a large herbivore. Its squat skeleton had a variety of features to support the heavy shell, including fused vertebrae and elephant-like short, stout limbs. They went extinct only about 10,000 years ago, possibly having been hunted to oblivion by early Americans. There is even some evidence that people used their empty shells as shelters.
Richard_OwenGlyptodon was formally named as a genus in 1839 by the extraordinary Sir Richard Owen (1804-1892). Owen was a giant of natural history through most of the 19th Century. He is most remembered for inventing the term Dinosauria (“terrible lizards”) and for being on the wrong side of history at the beginning of the Darwinian Revolution. He was apparently ambitious to the point of severity, and very tough on his contemporary scientists. Thomas Henry Huxley, for example, despised Owen for his treatment of his colleagues. Ironically, Huxley did considerable work on further describing Glyptodon in 1865. Owen had vision as well as sharp observational skills. He was a primary force in the eventual establishment of the Natural History Museum in London in 1881. It can be argued that this museum set the high standards of accessibility and research we now expect from all such institutions. Sir Richard Owen is such a large and well known figure I can simply refer you to one of many websites describing Owen’s life and contributions.

This post marks three complete years of Wooster’s Fossil of the Week. That’s 156 posts. You can visit the very first post (about a Devonian tabulate coral) and see how the entries have evolved, so to speak. We still have plenty more fossils to describe!


Gallo, V., Avilla, L.S., Pereira, R.C. and Absolon, B.A. 2013. Distributional patterns of herbivore megamammals during the Late Pleistocene of South America. Anais da Academia Brasileira de Ciências 85(2): 533-546.

Huxley, T.H. 1865. On the osteology of the genus Glyptodon. Philosophical Transactions of the Royal Society of London 155: 31-70.

Oliveira, É.V., Porpino, K.O. and Barreto, A.F. 2010. On the presence of Glyptotherium in the Late Pleistocene of northeastern Brazil, and the status of “Glyptodon” and “Chlamydotherium“. Paleobiogeographic implications. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen 258(3): 353-363.

Owen, R. 1839. Description of a tooth and part of the skeleton of the Glyptodon, a large quadruped of the edentate order, to which belongs the tessellated bony armor figured by Mr. Clift in his memoir on the remains of the Megatherium, brought to England by Sir Woodbine Parish. FGS Proceedings of the Geological Society of London 3: 108-113.

Wooster’s Fossils of the Week: Bits of a bamboo coral from the Lower Pleistocene of Sicily

October 27th, 2013

Keratoisis melitensis (Goldfuss, 1826) 585Earlier this summer I participated on a pre-conference field trip of the International Bryozoology Association throughout Sicily. We had an excellent time and saw many wondrous things. At one stop on the western side of the Milazzo Peninsula in the northwestern part of the island we collected fossils from a fascinating foraminiferal ooze deposit known as the “Yellow Calcareous Marls” (Gelasian, Lower Pleistocene). Among the fossils in this unit were the objects pictured above. They looked like finger bones at first, but are actually the internodes (calcitic skeletal elements) of an octocoral known as “bamboo coral“. This particular species is Keratoisis melitensis (Goldfuss, 1826). I’ve never seen this group before in the fossil record. (Note, by the way, that these specimens are encrusted by foraminiferans and octocoral holdfasts. This means they rolled around on the seafloor for an extended period before burial.)
ModernBambooCoralBamboo coral belongs to the octocoral group and is only a distant relative of reef-forming “hard corals” or scleractinians. They are common today in deep seas because they do not need sunlight for photosynthetic symbionts like most hard corals do. They have multiple polyps for feeding, none of which can retract back into the skeleton. That is why the surface of these internodes is so smooth and without the usual corallite holes. Above is a colony of white bamboo coral (Keratoisis flexibilis); image from Wikimedia Commons.
bamboo_coral_585Here we have a dried specimen of Keratoisis from the Florida Straits. You can see the white calcitic internodes of the skeleton separated from each other by the black nodes made of an organic material called gorgonin. This explains why our fossil specimens consist entirely of the isolated internodes — the chitinous parts did not survive fossilization. (Image from NOAA.)

Bamboo corals are long-lived, and it has been recently discovered that they incorporate trace elements in their skeletons as they grow, making them excellent specimens for studying changes in the chemistry and circulation of deep-sea waters. These fossils may thus someday be useful for sorting out the complex changes in the Mediterranean during the Pleistocene.


Langer M. 1989. The holdfast internodes and sclerites of Keratoisis melitensis Goldfuss 1826 Octocorallia in the Pliocene foraminifera marl Trubi of Milazzo Sicily Italy. Palaeontologische Zeitschrift 63: 15-24.

Sinclair, D.J., Williams, B., Allard, G., Ghaleb, B., Fallon, S., Ross, S.W. and Risk, M. 2011. Reproducibility of trace element profiles in a specimen of the deep-water bamboo coral Keratoisis sp. Geochimica et Cosmochimica Acta 75: 5101-5121.

Wooster’s Fossils of the Week: An ancient predator/prey system from the Lower Pleistocene of Sicily

September 15th, 2013

Bored and Borer for FOTWThe above fossils were collected from a Lower Pleistocene silty marl exposed near the Megara archaeological site east of Augusta, Sicily, Italy. I was on that epic International Bryozoology Association field trip this summer I’ve been blogging about. The shells in this locality are very abundant with hundreds of species represented, from foraminiferans to shark teeth. I thought this little vignette of a predator and its typical prey was worth noting.

On the far right is a naticid gastropod (moon snail). These mollusks are predators who kill and consume their prey by drilling holes into their shells with a specialized radula (a kind of tooth-bearing “tongue”). Their holes are distinctively beveled, with a wider portion on the outside narrowing to a smaller inner opening. The three organisms on the left all show boreholes indicating that they were likely killed and eaten by a naticid.

Or at least that’s the traditional story. A paper came out this year (Gorzelak et al., 2013) comparing predatory drill holes in shells with holes produced by physical abrasion by experimental tumbling. The sizes, shapes and locations of these abrasion-produced holes are shockingly similar to those made by drilling predators. It looks like we must be careful which holes we assign to predation and which were produced by other means.

As I look at the three victims above, two of them (the high-spired turritellid gastropod on the far left and the bivalve second from the right) have nicely beveled holes with almost perfectly circular shapes. The gastropod shell that is second from the left, though, presents problems. First, it has two holes that completely penetrate the shell. Predators occasionally bore a shell twice, but not very often. Second the holes are more irregular in shape and don’t have a noticeable beveling. This could be a feature of the thinner shell of this gastropod not recording the usual naticid boring evidence, or it could be the result of physical abrasion and not predation. It is a difficult call but an important one to those plotting the evolution of this predator/prey system through time.


Gorzelak, P., Salamon, M.A., Trzęsiok, D. and Niedźwiedzki, R. 2013. Drill holes and predation traces versus abrasion-induced artifacts revealed by tumbling experiments. PLoS ONE 8(3): e58528. doi:10.1371/journal.pone.0058528

Kelley, P.H. and Hansen, T.A. 2006. Comparisons of class- and lower taxon-level patterns in naticid gastropod predation, Cretaceous to Pleistocene of the US Coastal Plain. Palaeogeography, Palaeoclimatology, Palaeoecology 236: 302–320.

Kowalewski, M., Dulai, A. and Fürsich, F.T. 1998. A fossil record full of holes: The Phanerozoic history of drilling predation. Geology 26: 1091–1094.

Tyler, C.L. and Schiffbauer, J.D. 2012. The fidelity of microstructural drilling predation traces to gastropod radula morphology: paleoecological applications. Palaios 27: 658–666.

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