Wooster Geologists in ancient lakes

Manix031113ZZYZX, CALIFORNIA–Today Team Mojave studied the remains of ancient lake systems in the dry, dry desert. Early in the morning we drove west from Zzyzx to the Harvard Road exit off Interstate 15 and took a series of sandy roads to Bulwada Ridge on the shoreline of ancient Lake Manix. This Pleistocene, pluvial lake occupied a huge basin east of Barstow, California. Above we see laminated muds deposited in the lake itself. In the foreground are bouldery shoreline sediments. In the background you can see a scarp cut by the modern Mojave River (all underground at this point). Lake Manix was fed by the ancient Mojave River and supported a diverse fauna of fish and invertebrates.

MeagenBeachRidge031113Just to the north of the shoreline are long, twisting gravel bodies. Meagen Pollock is pondering one which has been truncated by modern erosion and now is topped by a beautiful desert pavement. (She found a beautifully polished artifact on one of these surfaces, by the way. It is a scraper with one bifacially-worked edge.) These gravel deposits are ancient beach ridges made by storm waves on Lake Manix.

OwlCanyonGroup031113After our visit to Lake Manix, we traveled to much older lake and river deposits in the Barstow Formation (Upper Miocene) exposed in Owl Canyon near Barstow. Our tradition here is that the students first explore the exposures and then bring back rocks to the picnic area for group analysis and discussion. The students above are clearly happy with all that they learned. (The two distinguished people in the background, by the way, are my parents Gary and Corinne Wilson who came to enjoy the geological fellowship.)

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A view from the other side of the table. Photo by Gary Wilson.

DesiccationCracks031113Kyle Burden found this beautiful example of two-stage desiccation cracks, preserved here as molds in the overlying sandstone.

RainbowBasin031113Another Wooster tradition is the group photograph in front of the outstanding syncline in the Barstow Formation exposed in nearby Rainbow Basin.

AftonSide031113Our final stop was in Afton Canyon about 50 miles east of Barstow. This narrow passageway is where Lake Manix drained into Soda and Silver Lakes, apparently more than once in a catastrophic manner. We crossed the mighty Mojave Rover on foot and then walked up this side canyon to check out the flood deposits and the lake deposits high on the skyline. These mark the highest level Lake Manix reached before it overtopped its dam and drained very quickly.

Another stimulating day which ended with a chicken dinner at the Desert Studies Center. Tomorrow we will return to the Barstow region but this time concentrating on structural issues and volcanic and plutonic rocks.

 

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Death Valley Days

BadwaterGroup031013DEATH VALLEY, CALIFORNIA–All geologists love Death Valley. No other place on Earth has such extraordinarily diverse geology combined with a modern infrastructure and a century of scientific study. The Wooster Geologists had a spectacular time in and around the valley today. Here we are above with the traditional group shot at Badwater. The weather could not have been better.

Zabriskie031013We left the Desert Studies Center at Zzyzx just after breakfast and drove through Baker and Shoshone to the southern end of Death Valley, seeing many wonderful sites. After lunch at the new National Park Service Furnace Creek Visitor Center, we then drove east and up out of the valley to Zabriskie Point. The above view has been published countless times by geologists and nature enthusiasts, but it has not lost its graphic power. We are looking here to the west at deeply eroded lake sediments of the Furnace Creek Formation. Towards the back of the light-colored material you can just make out the black streak of a basaltic intrusion.

ZabriskieOtherSide031013I think the other side of Zabriskie Point — the side looking out over Death Valley — is even more impressive. We see again the Furnace Creek Formation lake sediments, this time with alluvial deposits on top (visible on the right). These materials accumulated in an ancient lake and were lifted up and tilted by the tremendous faulting that formed Death Valley. The pinnacle is called Manly Beacon.

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We took advantage of the sunlight and high spirits to take a picture of our Desert Geology 2013 students.

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We continued east and then south to Dante’s View, where we looked down into Death Valley from the dizzy heights. In this image we see Telescope Peak towering at 11,049 feet of elevation, while much of the valley floor below is lower than sealevel.

DanteViewFan031013Looking straight down from Dante’s View to Badwater (on the far right), we can see a complete alluvial fan from the narrow channel in the mountain slope to the spreading apron of debris over the salt pan on the valley floor. Badwater Road skirts the periphery of the fan.

After Dante’s View, we continued east and returned to Zzyzx via Death Valley Junction, Shoshone and Baker. Again, I can think of nowhere else one can see so much geological diversity in a single day, from the steamy floor of Death Valley to the heights above where we could walk through patches of snow.

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Wooster’s Fossil of the Week: A brittle star from the Upper Jurassic of Germany

Ophiopetra lithographica aboral larger 010813_585Wooster geologists have again greatly benefited from the donation of a collection by an alumnus. George Chambers (’79), a successful professional photographer, sent us several boxes of minerals, rocks and fossils he had acquired in his lifelong passion for geology. (George was a geology major at Wooster in the class just after mine.) Among the many world-class specimens he gave us are two fossil ophiuroids (brittle stars). They are Ophiopetra lithographica Enay and Hess, 1962, from the Lower Hienheim Beds (Lower Tithonian, Upper Jurassic) near Regensburg, Germany. They are part of the “Fossillagerstätte Hienheim“, a preserved brittle star ecosystem in a lagoon at the edge of a Late Jurassic sea. This is the same set of lithographic limestones in which the famous bird fossil Archaeopteryx was found.
Ophiopetra lithographica 010813_585In both these images you see the spiny arms of the brittle stars twisted about. It is their flexibility and snake-like movements in life that provoked the scientific name ophiuroids (serpent-forms) for the brittle stars. The “brittle” term comes from their ability to autotomize (spontaneously detach) their arms when threatened, leaving a squirming distraction for a predator as they escape.
Ophiopetra lithographica aboral 010813_585Ophiopetra lithographica is probably the most common fossil brittle star known. It was preserved by the countless millions in these Jurassic lagoons in Germany. Most geologists believe they were buried by fine-grained carbonate sediment suspended by sudden storms. As you can see in the above close-up, the preservation of the plates and spines is remarkable.

Most brittle stars are suspension feeders (sorting out food particles from the water), deposit feeders (eating organic material in the sediment) or scavengers. Ophiopetra lithographica may have been a carnivore with its heavily-spined arms and strong jaws. It likely ate small arthropods on the seafloor.

The evolution of brittle stars is interesting and controversial. They were relatively common in the Paleozoic and then just barely survived the Permian extinctions. Their rapid evolution into a variety of taxa in the Mesozoic and Cenozoic has led to many debates about their phylogeny. Even the placement of Ophiopetra into a family is a problem. Does it belong to the Family Aplocomidae where it was originally placed or to the older Family Ophiolepididae as has been recently suggested?

Our students will enjoy these fine fossils in the invertebrate paleontology course. They have doubled our collection of brittle stars! Thank you again to George Chambers for his thoughtfulness and generosity.

References:

Enay, R. and Hess, H. 1962. Sur la découvertes d’Ophiures (Ophiopetra lithographica n.g. n.sp.) dans le Jurassique supérieur du Haut-Valromey (Jura méridional). Eclogae geologicae Helvetiae 55: 657-678.

Hess, H. and Meyer, C.A. 2008. A new ophiuroid (Geocoma schoentalensis sp. nov.) from the Middle Jurassic of northeastern Switzerland and remarks on the Family Aplocomidae Hess 1965. Swiss Journal of Geosciences 101: 29-40.

Röper, M. and Rothgänger, M. 1998. Die Plattenkalke von Hienheim (Landkreis Kelheim) – Echinodermen-Biotope im Südfränkischen Jura. Eichendorf (Eichendorf Verlag), 110 S.

Stöhr, S. 2012. Ophiuroid (Echinodermata) systematics—where do we come from, where do we stand and where should we go? In: Kroh, A. and Reich, M. (Eds.) Echinoderm Research 2010: Proceedings of the Seventh European Conference on Echinoderms, Göttingen, Germany, 2–9 October 2010. Zoosymposia, 7: 147-161.

Thuy, B., Klompmaker, A.A. and Jagt, J.W.M. 2012. Late Triassic (Rhaetian) ophiuroids from Winterswijk, the Netherlands; with comments on the systematic position of Aplocoma (Echinodermata, Ophiolepididae). In: Kroh, A. and Reich, M. (Eds.) Echinoderm Research 2010: Proceedings of the Seventh European Conference on Echinoderms, Göttingen, Germany, 2–9 October 2010. Zoosymposia, 7: 163-172.

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Wooster Geologists return to the Mojave Desert

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ZZYZX, CALIFORNIA–It is officially now a Wooster Geology tradition: every other year we take a Spring Break field trip with students, faculty and staff. So far all of our trips have been to the Mojave Desert, for reasons that will be apparent in the following posts. This expedition is the highlight of our Desert Geology course this spring.  This year we have the largest group yet: eleven students, three faculty (Meagen Pollock, Shelley Judge and me — Greg Wiles could not join us because of his leave activities) and two staff (Administrative Coordinator Patrice Reeder and Geological Technician Nick Wiesenberg). We are delighted to also have with us Yoav Avni, a desert geomorphologist with the Geological Survey of Israel (and my good colleague and friend). Four vans of enthusiastic geologists!

We left Wooster very early this morning (5:30 a.m.) to catch a non-stop flight to Las Vegas from Cleveland. After picking up our vehicles at the Las Vegas airport, we drove to the Desert Studies Center (DSC) in delightfully named Zzyzx, California. We’ve stayed here many times before. The station is shown above from the mountain just to its west. Astute observers who visited this little paradise before may notice on the far right side a new solar array to supply electricity to the facility. It is all off the grid and self-contained. It feels in some ways like being on a ship at sea. On the far side of the station you can see the expanse of Soda Lake and some of the mountain ranges in the Mojave National Preserve.

NickKyle030913This year we arrived a bit earlier than usual, so we got a chance to explore the neighborhood around the DSC. Here you can see Nick Wiesenberg and Kyle Burden checking out some nearby outcrops of deformed carbonates (probably the upper part of the Bird Springs Formation, which is Permian in age). This was a chance to break in our boots and stretch our legs before settling into our quarters. The weather is overcast right now, but will dramatically improve tomorrow for the rest of the week.

The weather promises to be excellent for the week we are in the Mojave. All is well as the adventure begins!

 

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One of the many diverse results of being a geology major: the adventures of Will Driscoll (’05) in evolutionary ecology

WillDriscoll05_030513WOOSTER, OHIO–Yesterday Greg Wiles and I attended a Biology Department Seminar given by our former student Will Driscoll (Geology ’05). Will was in all our standard departmental courses and did his Independent Study project with Dr. Wiles in dendrochronology. Yet here he was giving a presentation to the Biology Department. How did this happen? It is yet another example of the utility of a liberal arts major in science … and what persistence and great ideas can lead you.

I well remember the day during Will’s senior year that he brought me an essay he wanted me to read. For one thing, it was an essay unconnected with any course — Will just wanted to write down some ideas and get a response. The essay was about evolutionary ecology and morphogenesis. To say this came from left field would be an understatement. I had no idea Will had such concepts, and they were extremely well developed and expressed. Will applied to the Department of Ecology and Evolutionary Biology at The University of Arizona (the top program in the nation for this subject). He finished his PhD there last year and is now a Postdoctoral Research Fellow in the Département de Biologie, École Normale Supérieure, Paris, France. That is a long way from Scovel Hall!

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A small swarm of toxic Prymnesium parvum (small golden cells) attacks a rotifer accustomed to grazing on unicellular algae. The toxic algae help themselves to a meal, and in the process help all of the algae that the rotifer might have otherwise eaten. (Image and caption from Will Driscoll.)

Will’s specialty, and the topic of his seminar yesterday, is in a broad sense on “the ecological drivers and consequences of multilevel selection”. He is pursuing this interest now with studies on what has been called “microbial sociobiology”. The title of his Wooster talk was “The ecological consequences of microbial sociality”. He is looking at the behavior of microbes as cooperative groups and all this means for evolution and ecology. His stories about toxic bloom-forming algae were amazing, opening up new dimensions on how to place single-celled organisms into our models of behavioral evolution. Will himself can tell you much more about his research and ideas on his website.

Will’s presentation was inspiring at (appropriately) multiple levels: the science was novel, fascinating and provocative, and Will’s enthusiasm and skills reminded us yet again why teaching at Wooster is simply the best job in the world.

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Wooster’s Fossils of the Week: More bryozoan etchings and an African slug surprise

CheilostomeEtchings2_585This is the inside of a modern cockle shell (Dinocardium vanhyningi) found on a beach in Wilmington, North Carolina. Across the surface is a radiating series of pits, each of which was formed under a zooid of an encrusting cheilostome bryozoan colony, much like Ropalonaria described last week. This etched shell gives me an opportunity to tell a cautionary tale of trace fossils, slugs and taxonomy.
pdt12291This scanning electron microscope image was taken by my friend and colleague Paul Taylor at The Natural History Museum in London. It shows a cheilostome bryozoan etching (the elongated pits) across a shell surface very much like the modern shell at the top of the page. In the lower right is a bit of the cheilostome bryozoan Amphiblestrum. This particular bryozoan did not make the pits themselves (it is oriented in a different direction), but another colony of the same species likely did. This assemblage comes from the Coralline Crag Formation (Pliocene) exposed in Broom Pit, Suffolk, England.

In 1999, Paul Taylor, Richard Bromley and I published a paper in the journal Palaeontology describing these bryozoan etching pits as a new ichnogenus (a category of trace fossil) with a Late Cretaceous to Holocene range. We invented (or so we thought) the name Leptichnus using the Greek roots leptos (‘flimsy, delicate, subtle’) and ichnos (‘track, footprint’). It was a fun little project, and we provided a useful name to embed this fossil in the literature.

This past fall, thirteen years after publication, I decided to write a Fossil of the Week entry on Leptichnus. In my innocence I searched Google for “Leptichnus” and was very surprised to find it has a Wikipedia page — and it was an East African slug! Yes, the beautiful name Leptichnus was preoccupied by a urocyclid terrestrial gastropod, Leptichnus Simroth, 1896, found in Kenya and Tanzania. 1896 is a long time before 1999, so Simroth’s name has priority over ours. The ichnogenus Leptichnus Taylor, Wilson and Bromley, 1999, thus became a junior homonym of the gastropod genus Leptichnus Simroth, 1896. We had to come up with a new name for it.
LeptichnusOriginalDescription_585 copyAbove is the original 1896 description of Leptichnus The Slug by Heinrich Rudolf Simroth (1851-1917). He apparently came up with the name because this shell-less snail left a subtle trail behind it when it slithered. It is the first time I’ve seen the -ichnus suffix used for anything but a trace fossil.
Heinrich_Simroth_1902Herr Doktor Professor Simroth was a German zoologist and malacologist educated at the University of Leipzig. He was a schoolteacher for his whole career, doing prodigious research in his spare time. His speciality was, unsurprisingly, terrestrial slugs. He worked on specimens brought back by scientific expeditions, including one in the short-lived colony of German East Africa. It is from this collected material he described Leptichnus. Simroth’s type collection was long considered lost, but many specimens were recently rediscovered in Berlin (Glaubrecht, 2010). These do not, alas, include any representatives of Leptichnus. The image above is of Simroth in 1902.

Taylor, Wilson and Bromley (2013) proposed the new name Finichnus to replace Leptichnus Taylor, Wilson and Bromley, 1999. To preserve the meaning of the original name, we substituted the Greek finos (‘fine, delicate’) for leptos.

The lesson of this story? Search, search, search for homonyms of new taxonomic names. In our defense, searching wasn’t as easy back in the 90s (Google’s search engine came online in 2000, for example, and Wikipedia began in 2001). At least the adventure introduced us to Heinrich Rudolf Simroth and his slugs!

References:

Glaubrecht, M. 2010. Slug(-gish) science, or an annotated catalogue of the types of tropical vaginulid and agriolimacid pulmonates (Mollusca, Gastropoda), described by Heinrich Simroth (1851–1917), in the Natural History Museum Berlin. Zoosystematics and Evolution 86: 15–335.

Rosso, A. 2008. Leptichnus tortus isp. nov., a new cheilostome etching and comments on other bryozoan-produced trace fossils. Studi Trentini – Acta Geologica 83: 75–85.

Simroth, H. 1896. Über bekannte und neue Urocycliden. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 19: 281–312.

Taylor, P.D., Wilson, M.A. and Bromley, R.G. 1999. Leptichnus, a new ichnogenus for etchings made by cheilostome bryozoans into calcareous substrates. Palaeontology 42: 595–604.

Taylor, P.D., Wilson, M.A. and Bromley, R.G. 2013. Finichnus, a new name for the ichnogenus Leptichnus Taylor, Wilson and Bromley, 1999, preoccupied by Leptichnus Simroth, 1896 (Mollusca, Gastropoda). Palaeontology (in press).

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The Dendrochronology Team of Wooster Geologists makes its television debut

Gwiles022813aBarn Detectives” is a recent episode of the television show Our Ohio, and it features Dr. Greg Wiles and his team of crack dendrochronologists. You can view the video by clicking the link. It is very well done. The project described in the program is the dating of the Emerson barn in Apple Creek, Ohio. These Wooster scientists study the tree rings in the beams which were used in the original structure. Careful analysis of these rings will show the year the old-growth trees were cut for timber, and thus the date of the building. This work not only gives the Emerson family a date for a treasured building, it also provides additional dendrochronological data for studying climate change in the last two centuries.

Nwiesenberg022813Our geological technician Nick Wiesenberg provides explanations of the process from the barn, a local old-growth forest (Johnson Woods, see above), and the dendrochronology lab at Wooster.

lvargo022813Geology senior Lauren Vargo describes the value of tree rings for climate history, and is shown in several action shots of coring and sanding.

anash022813Andy Nash, another geology senior, describes the construction of “floating chronologies” from tree cores that are eventually tied to the larger dendrochronological record to give dates to the wood. (With an accuracy, as Greg likes to say, of “plus or minus zero years”.)

gwiles022813bBack in the lab, Greg shows how the cores from the Emerson barn are counted and measured with our video microscope system. On the monitor is a magnified view of rings from the Emerson barn.

nwiesenberg022813bNick had the honor of announcing the calculated date the trees were cut to make the barn’s beams: (Spoiler Alert!) the Fall of 1845. The ground would have been hard then and the farmers would have had time to collect materials for the construction.

It was great fun to see our students and colleagues explain their work so well, and to show the world the enthusiasm and professional skills of Wooster’s dendrochronologists.

The full “Barn Detectives” video is available on YouTube at this link.

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Wooster’s Fossil of the Week: A bryozoan etching (Upper Ordovician of Indiana)

Ropalonaria_venosa_585_010213Another trace fossil of a sort this week. Above you see the dorsal valve exterior of a strophomenid brachiopod from the Upper Ordovician of southeastern Indiana. Across the surface is a network of grooves looking a bit like a spider web. This is a feature formed when a soft-bodied ctenostome bryozoan colony etched its way down into the shell it was encrusting. Ropalonaria venosa Ulrich, 1879 is the official name of this fossil.
Ropalonaria_close_010513Above is a closer view of the same Ropalonaria venosa. Tiny crystals of yellow dolomite fill the excavations. The ctenostome bryozoan that made it had no skeleton and used some sort of chemical to dissolve the shell beneath it. The fidelity of this etching is good enough to identify various details of the colony structure and zooecial form. This is where our fossil classification system goes a bit awry: Is Ropalonaria a trace fossil (evidence of animal activity) or a kind of external mold of the original organism? Arguments have been made for each category, and the name Ropalonaria shows up on lists of both trace fossils and body fossils.
Ulrich_EO_1927Ropalonaria venosa is the type species of the genus Ropalonaria erected by Edward Oscar Ulrich in 1879 (above in 1927). E.O. Ulrich, as he is better known, was one of the most colorful and controversial geologists of the late 19th and early 20th century. He was born in Covington, Kentucky, in 1857. Covington is across the Ohio River from Cincinnati, Ohio, and is undergirded by the famous fossiliferous limestones and shales of the Cincinnatian Group (Upper Ordovician). Ulrich started as a child collecting fossils in the region. He was an early member of the Cincinnati Society of Natural History, often bringing fossils to meetings for identifications. (There he met another young man very interested in fossils: the future paleontologist Charles Schuchert. Schuchert was the advisor of my advisor’s advisor, so he’s in my “academic genealogy”.)

Ulrich took courses at German Wallace College (today’s Baldwin Wallace University in Berea, Ohio) and the Ohio Medical College. He had an eclectic youth exploring all sorts of topics, from opera to spiritualism, but always kept geology and fossils close to his heart. He had an adventurous stint as a superintendent in a Colorado silver mine. Returning back east, Ulrich became an enormously productive geologist with the geological surveys of Illinois, Minnesota, and Ohio. He was President of the Paleontological Society in 1915. In 1931 he received the Mary Clark Thompson Medal from the National Academy of Sciences, and the next year the Geological Society of America awarded him the prestigious Penrose Medal. He died in 1944 in Washington, D.C.

E.O. Ulrich is still a polarizing figure in American geology. He is famous for resisting the modern concept of facies in sedimentary geology, preferring a concept now known as “layer cake stratigraphy“. (In his defense, the rocks in the Cincinnati area really do fit much of his model; his error was extending it much too far.) Ulrich also has a reputation as a bit of a “splitter” in paleontology. (Someone who makes more species than necessary by “splitting” groups into smaller subgroups.)

Despite what we think of E.O. Ulrich today, his paleontological contributions have mostly held up, including the description of the intriguing fossil Ropalonaria.

References:

Bassler, R.S. 1944. Memorial to Edward Oscar Ulrich. Proceedings of the Geological Society of America for 1944: 331–351.

Pohowsky, R.A. 1978. The boring ctenostomate Bryozoa: taxonomy and paleobiology based on cavities in calcareous substrata. Bulletins of American Paleontology 73(301): 192 p.

Ruedemann, R. 1946. Biographical memoir of Edward Oscar Ulrich, 1857-1944. National Academy of Sciences of the United States of America. Biographical Memoirs, Volume XXIV, 7th Memoir, 24 pp.

Ulrich, E.O. 1879. Descriptions of new genera and species of fossils from the Lower Silurian about Cincinnati: Journal of the Cincinnati Society of Natural History 2: 8-30.

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Celebrating the achievements of Wooster Geologists

2013Geo AwardWinners

WOOSTER, OHIO –One of the pleasures of being the chair of the Geology Department at Wooster is that I get to go to the annual college Awards Banquet with some of our best students. Tonight we celebrate three young women who have done especially well at Wooster. On the left is Whitney Sims (’13) of Maple Heights, Ohio. She received the Charles B. Moke Prize, which is a “field instrument or device” awarded to the graduating senior who has shown the greatest improvement during his or her college career. (Whitney’s award was a new iPad — coolest prize of the evening.) In the middle is Tricia Hall (’14) of Marion, Ohio. She won the Karl Ver Steeg Prize in Geology and Geography, which goes to the geology major who has the highest standing in the middle of the junior year. On the right is Kit Price (’13) of Ann Arbor, Michigan. Her award was the Robert W. McDowell Prize in Geology for having the highest general standing among geology majors in the junior and senior years.

Congratulations to Whitney, Tricia and Kit! We are very proud of them and all our Wooster Geologists.

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Wooster’s Fossil of the Week: Encrusting tubes from the Devonian of Michigan

HederelloidSEM_DevMIThe scanning electron microscope (SEM) image above shows the tubes of the encrusting group known as hederelloids. They are among my favorite fossils. I was reminded of them recently while reading this advertisement for a novel in which, to my great surprise, hederelloids are a primary part of the plot! A mysterious black “fouling” destroys shipping. Scientists discover that it is made by a group long thought to be extinct — the hederelloids! There is even a page talking about the “science” behind the story. (Although I would think if they were serious they would spell “bryozoan” correctly.)
HederellaOH3The hederelloids are a group of colonial encrusting organisms found from the Silurian through the Permian, with possible members in the Ordovician and the Triassic (Taylor and Wilson, 2008). They were entirely marine and were most common by far on Devonian brachiopods and corals. They are “runner-like” encrusters, meaning they grew sequentially across the substrate budding out new members of the colony. Their zooids (the skeletons that contained the individuals) are usually curved and made of microprismatic calcite secreted from the inside only. (This latter feature meant they could repair damage such as boreholes with patches from the inside; see Wilson and Taylor, 2006). The specimen above is a Devonian spiriferid brachiopod from northwestern Ohio with a hederelloid colony encrusting the dorsal valve.
HedsSEMpdtDevNYHederelloids were very diverse in their time. The SEM image above (courtesy of Paul Taylor at the Natural History Museum, London) shows at least two types of hederelloid on a rugose coral from the Devonian of New York. The large tube at the bottom has several lateral buds. At the very top of the view you can see a much smaller hederelloid growing in the opposite direction.
DevonianIowaHederelloidUSNM78639The earliest workers on hederelloids thought that they were cyclostome bryozoans of some type (see Bassler, 1939). They look superficially like the common genera Corynotrypa, Cuffeyella and Stomatopora. Hederelloids, though, are significantly larger on the whole, they do not bud in the same pattern as bryozoans, and they do not have lamellar walls. Their shell microstructure and budding patterns suggests instead that they may be related to the phoronids, making them a kind of lophophorate (lophophore-bearing organism; the lophophore is a tentacular feeding device). They could probably, like bryozoans, retract the lophophore into their tubes when necessary. The above photograph shows the underside of a hederelloid colony from the Devonian of Iowa. Note the distinctive budding pattern. The scattered spirals are microconchids.

HedCloseUpDevNYThis is a nice collection of hederelloids from the Devonian of New York. Notice the diversity of sizes, shapes and budding patterns. How can you not be fascinated by such enigmatic little creatures?

References:

Bassler, R.S. 1939. The Hederelloidea. A suborder of Paleozoic cyclostomatous Bryozoa. Proceedings of the United States National Museum 87: 25-91.

Taylor, P.D. and Wilson, M.A. 2008. Morphology and affinities of hederelloid “bryozoans”, p. 301-309.  In: Hageman, S.J., Key, M.M., Jr., and Winston, J.E. (eds.), Bryozoan Studies 2007: Proceedings of the 14th International Bryozoology Conference, Boone, North Carolina, July 1-8, 2007.  Virginia Museum of Natural History Special Publication 15.

Taylor, P.D., Vinn, O. and Wilson, M.A. 2010. Evolution of biomineralization in ‘lophophorates’. Special Papers in Palaeontology 84: 317-333.

Wilson, M.A. and Taylor, P.D. 2006. Predatory drillholes and partial mortality in Devonian colonial metazoans. Geology 34:565-568.

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