Wooster’s Fossil of the Week: Ammonite septa from the Upper Cretaceous of South Dakota

January 27th, 2017

This week we have an ammonite from the Pierre Shale (Upper Cretaceous, Campanian-Maastrichtian) of southwestern South Dakota. It was collected on a wonderful field expedition in June 2008 with my friend Paul Taylor (The Natural History Museum, London) and my student John Sime. Ammonites are extremely common in this interval, but I like this one because it is broken in such a way to expose its complex internal walls, called septa. We are looking at a cross-section of a coiled ammonite showing an early whorl in the upper left surrounded by a later whorl. The septa are fluted at their margins as they meet the outer wall. The wiggly boundary line between a septum and the outer wall is called a suture.

Ammonite septa are remarkably complex, showing fractal patterns. Why did these animals, extinct for 66 million years, evolve such complexity in their septa? This is a hotly debated topic in paleontology. The most popular explanations include strengthening the walls of the shell to resist hydrostatic pressure at depth, buttressing the shell against the crushing pressures of biting predators, and increasing soft-tissue (mantle) surface areas for physiological advantages. Klug and Hoffman (2015) have an excellent summary of these ideas. Lemanis et al. (2016) have a fascinating mathematical study that suggests the answer in many cases complex sutures “seem to increase resistance to point loads, such as would be from predators.”

The astonishing English polymath Robert Hooke (1635-1703) took considerable interest in ammonites and their complicated septa. We have no contemporary images of him, but based on descriptions, Rita Greer painted the above portrait in 2004. Hooke’s life was as complex as the suture patterns he studied, so I leave you to other sources on him. Note in the portrait above, though, the ammonite!

These are drawings by Robert Hooke of ammonites and their suture patterns (from Kusukawa, 2013). It is a single image mirror-reversed. Beautiful.

References:

Derham W. 1726. Philosophical experiments and observations of the late eminent Dr. Robert Hooke, S.R.S. and Geom. Prof. Gresh., and other eminent virtuoso’s in his time. London: Derham.

Garcia-Ruiz, J.M., Checa, A. and Rivas, P. 1990. On the origin of ammonite sutures. Paleobiology 16: 349-354.

Klug, C. and Hoffmann, R. 2015. Ammonoid septa and sutures. In: Ammonoid Paleobiology: From anatomy to ecology (p. 45-90). Springer Netherlands.

Kusukawa, S. 2013. Drawings of fossils by Robert Hooke and Richard Waller. Notes Rec. R. Soc., 67: 123-138.

Lemanis, R., Zachow, S. and Hoffmann, R. 2016. Comparative cephalopod shell strength and the role of septum morphology on stress distribution. PeerJ 4:e2434

Wooster’s Fossils of the Week: Revisiting a pair of hyoliths from the Middle Ordovician of Estonia

January 20th, 2017

We met these modest internal molds of the mysterious hyoliths about five years ago. With a dramatic new development in hyolith studies, they are worth seeing again.

These fossils are internal molds (the sediment that filled the shell) of of flattened cones composed of the carbonate mineral aragonite. The aragonite shells dissolved away after burial, leaving the cemented sediment behind. That’s what we see above, in their stark simplicity. (We also see wiggly indentations that are the trace fossil Arachnostega, which is what I collected them for in the first place.) They were found in the Middle Ordovician of Estonia.

Hyalites, though common throughout the Paleozoic, have been difficult to place in a taxonomic category. Because of their easily-dissolved aragonite skeletons, most fossils are like these — simple molds and casts. A few were found with some preserved internal organs, which added to the intrigue. Their flattened conical shells had a hinged lid (operculum) over the open end. Extending from each side in the space between the operculum and cone were two calcareous rods called helens (a name deliberately chosen so as not to evoke a particular function). They were rumored to be deposit-feeders, based on no real evidence, it turns out.

An excellent paper appeared earlier this month showing dramatic evidence of hyolith soft parts in the Cambrian of western Canada (Moysiuk et al., 2017). The authors reconstruct the iconic Cambrian hyolith Haplophrentis “as a semi-sessile, epibenthic suspension feeder that could use its helens to elevate its tubular body above the sea floor”. Their primary evidence is a magnificently preserved lophophore (tentacular filter-feeding apparatus) and a U-shaped digestive tract with a dorsolateral anus. These features not only give the hyoliths a life mode and feeding habit, they place them systematically among the lophophorates, a group that includes brachiopods, phoronids and bryozoans.

Haplophrentis in the Burgess Shale (Middle Cambrian) at the Walcott Quarry, Burgess Pass, British Columbia, Canada.

Reconstruction of Haplophrentis on the Cambrian sea floor. The tentacular lophophore is seen extending out underneath the operculum. Beautiful art by D. Dufault of the Royal Ontario Museum.

It’s not often we see such dramatic changes in the taxonomic placement and paleoecological habits of a large, extinct group. It is also not often that invertebrate fossils make headlines!

Reference:

Moysiuk, J., Smith, M.R. and Caron, J.B. 2017. Hyoliths are Palaeozoic lophophorates. Nature doi:10.1038/nature20804

Wooster’s Fossils of the Week: New review paper on architectural design of trace fossils

January 13th, 2017

screen-shot-2016-12-04-at-2-59-29-pmLast year my friend Luis Buatois led a massive project to review essentially all trace fossil invertebrate ichnogenera (523!) to place them in a series architectural design categories (79). This is a new way to assess patterns of ichnodisparity (variability in morphology of trace fossils). I was proud to have a role in this work, along with Max Wisshak and Gabriela Mángano. The paper has now appeared in Earth-Science Reviews (Buatois et al., 2017).

My contributions were mostly with the bioerosion traces (along with Max), so I show Figure 65 from the paper above. Its caption: Examples of pouch borings (Category 65). A: Petroxestes pera, Ordovician, Whitewater Formation, Ohio, USA. B: Rogerella isp. in a belemnite rostrum. Jurassic, Spain. C: SEM of Rogerella isp. in an epoxy resin cast of an Echinocorys echinoid test. Upper Cretaceous, Palm Bay, Thanet, Kent, UK. D: Umbichnus inopinatus in a bivalve shell. Lower Pliocene, Huelva, Spain. Photograph courtesy of Jordi Martinell. E: SEM of Aurimorpha varia in an epoxy resin cast, including the holotype in the upper right. Middle Pennsylvanian, Desmoinesian, Boggy Formation, Buckhorn Asphalt Quarry, Oklahoma, USA.

The abstract of the paper explains the work and our ambitions for it: Ichnodisparity has been recently introduced as a concept to assess the variability of morphologic plans in biogenic structures, revealing major innovations in body plan, locomotory system and/or behavioral program. Whereas ichnodiversity is measured in terms of the number of ichnotaxa (i.e. ichnogenera or ichnospecies), ichnodisparity is evaluated based on the identification of categories of architectural design. Seventy-nine categories of architectural designs (58 for bioturbation structures and 21 for bioerosion structures), encompassing 523 ichnogenera (417 for bioturbation structures and 106 for bioerosion structures), are defined. They are restricted to invertebrate ichnotaxa, whereas vertebrate trace fossils were not included. Although the scheme is designed to be comprehensive, the proposed categories are necessarily works in progress because of the state of flux in ichnotaxonomy and the need to adjust the definitions of categories according to the scope and scale of the analysis. Although it may be said that the establishment of categories of architectural design is to a certain degree a subjective enterprise, this is not different from ichnotaxonomy because classifying trace fossils from a taxonomic perspective implies observing the morphology of the trace and interpreting it in terms of behavior. The concept of ichnodisparity is free of some of the vagaries involved in ichnotaxonomy. The fact that ichnodiversity and ichnodisparity exhibit different trajectories during the Phanerozoic underscores the importance of adding the latter to the ichnologic toolkit.
screen-shot-2016-12-04-at-3-03-44-pmFigure 80 above contrasts ichnodisparity and ichnodiversity. The five different ichnogenera illustrated in the upper portion of the diagram represent minor variations of the same architectural design. The lower portion of the diagram represents the same ichnodiversity level, but with a much higher ichnodisparity. The two hypothetical situations bear different implications regarding the extent of evolutionary innovations.

We hope that this work is long useful in paleontology, especially for projects sorting out the evolution of invertebrate communities.

Reference:

Buatois, L., Wisshak, M., Wilson, M.A. and Mángano, G. 2017. Categories of architectural designs in trace fossils: A measure of ichnodisparity. Earth-Science Reviews 164: 102-181.

Wooster’s Fossils of the Week: Upper Ordovician brachiopods and bryozoans from paleontology class collections

January 6th, 2017

1-geopetal-tommyLast semester the Invertebrate Paleontology class at Wooster had its annual field trip into the Upper Ordovician of southern Ohio. We had a great, if a bit muddy, time collecting fossils for each student’s semester-long project preparing, identifying, and interpreting their specimens. Like all research, especially when it starts in the field, there were discoveries and surprises. I always highlight a particular specimen collecting by a student in this blog.

Above is a cross-section of a specimen found by Tommy Peterson (’19). It is the rhynchonellid brachiopod Hiscobeccus capax almost completely enveloped by an encrusting trepostome bryozoan. We’ve cut through the center of the brachiopod, revealing gray micritic sediment and clear calcite crystals. We can infer from this simple specimen that the brachiopod died and its shell remained articulated. Sediment drifted in, filling the bottom half of the shell. The bryozoan eventually sealed it all up as it used the brachiopod shell for a hard substrate on a muddy seafloor. The remaining void space was filled in by the precipitation of calcite crystals. You can see that the crystals nucleated from the outer margin of the cavity and grew inwards, a kind of calcareous geode. I’m intrigued by the irregular sediment surface and the manner in which calcite nucleated upwards from it. I suspect this sediment was itself cemented before the calcite crystals appeared.

This kind of structure is called a geopetal. It shows the “way up” at the time of crystal formation. Gravity held the pocket of sediment in the bottom of the shell, leaving the void at the top. Nice little specimen.

2-constellaria-alexisThis star-studded bryozoan found by Alexis Lanier (’20) was going to be the Fossil of the Week, but then I saw that last year I highlighted the very same species! I think the bryozoan Constellaria is cool. Read all about it and its history at the link.

3-table-of-traysHere are the completed specimen trays for half the class. (Grading this project took, as you might imagine, considerable time!). Every week in lab, after we had done the assigned work, we got out the trays and cleaned, prepared, and identified the specimens. Students learned how to use the rock saws and make acetate peels of the bryozoans and corals.

4-tray-insideInside a typical tray. We are very grateful for the many online sources to aid identification of these Cincinnatian fossils. Three in particular were most valuable: Alycia Stigall’s Digital Atlas of Ordovician Life, Steve Holland’s stratigraphic and paleontological guide to the Cincinnatian, and the spectacular Dry Dredgers website.

Ohio is a paleontological paradise!

Wooster’s Fossils of the Week: Ordovician bioerosion trace fossils

December 9th, 2016

screen-shot-2016-12-03-at-2-06-03-pmThis week’s post is a celebration of the appearance of a remarkable two-volume work on trace fossils and evolution. The editors and major authors are my friends Gabriela Mángano and Luis Buatois (University of Saskatchewan). They are extraordinary geologists, paleontologists and ichnologists (specialists on trace fossils). They led this massive effort of multiple authors and thousands of manuscript pages. Turns out they are inspiring scientific leaders as well as sharp-eyed editors.

My contribution is in the first volume within a chapter (co-authored with Gabriela, Luis, and Mary Droser of the University of California, Riverside) entitled “The Great Ordovician Biodiversification event”. We examine here the relationship between trace fossils and the critical evolution of marine communities through the Ordovician. My main responsibility was sorting out the changes in the bioeroders over the course of the period. Way back in 2001, Tim Palmer and I noticed a rise in bioerosion trace fossil diversity and abundance in the Middle and Late Ordovician. We grandly called it the “Ordovician Bioerosion Revolution”. The concept and name stuck.

The top image is Fig. 4.8 from the book. The caption: Upper Ordovician bioerosion structures. (a) Trypanites weisi (cross-sectional view) in a carbonate hardground. Katian, Grant Lake Limestone, near Washington, Kentucky, USA; (b) Trypanites weisi (bedding-plane view) in a carbonate hardground. Katian, Grant Lake Limestone, near Manchester, Ohio, USA; (c) Palaeosabella isp. in a trepostome bryozoan. Katian, Whitewater Formation, near Richmond, Indiana, USA; (d) Petroxestes pera. Katian, Whitewater Formation, Caesar Creek Lake emergency spillway, near Waynesville, Ohio, USA; (e) Ropalonaria venosa in a strophomenid brachiopod. Katian, Liberty Formation near Brookville, Indiana, USA.

screen-shot-2016-12-03-at-2-08-42-pmThe cover of the book, which is described here on the publisher’s website.

References:

Mángano, G., Buatois, L., Wilson, M.A. and Droser, M. 2016. The Great Ordovician Biodiversification event, p. 127-156. In: Mángano, G. and Buatois, L. (eds.), The trace-fossil record of major evolutionary events. Topics in Geobiology 39 (Springer).

Wilson, M..A. and Palmer, T.J. 2001. The Ordovician Bioerosion Revolution. Geological Society of America Annual Meeting, Boston, Paper No. 104-0. November 7, 2001.

Wilson, M.A. and Palmer, T.J. 2006. Patterns and processes in the Ordovician Bioerosion Revolution. Ichnos 13: 109-112.

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.”

References:

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.

Wooster’s Fossils of the Week: Demosponge borings in a muricid gastropod from Florida

November 4th, 2016

entobia-snail-2Technically these are “subfossils” since this appears to be an old shell still within the Holocene, although it is possibly eroded out of Pleistocene sediments and then redeposited on a Florida beach. It is a muricid snail eroded enough to erase any specific characters for further identification. It is cool because it is thoroughly bored by clionaid demosponges, producing a beautiful pattern of holes given the ichnological name Entobia Bronn 1838.

entobia-snail-1On the left side of the aperture of this snail shell is a fine reticulate pattern from an encrusting cheilostome bryozoan, also punctured by Entobia. That bryozoan is in a favored place for filter-feeding encrusters on snail shells, so it likely was there during the life of the snail.

As a trace fossil this structure would be known as Entobia. It is very common in the fossil record, especially in the Cretaceous and later.

Bronn 041616Entobia is common in the fossil record, especially in calcareous rocks and fossils from the Cretaceous on. The ichnotaxon was named (but apparently not described) in 1838 by Heinrich Georg Bronn (1800-1862), a German geologist and paleontologist we’ve met before in this blog. He had a doctoral degree from the University of Heidelberg, where he then taught as a professor of natural history until his death. He was a visionary scientist who had some interesting pre-Darwinian ideas about life’s history. He didn’t fully accept “Darwinism” at the end of his life, but he made the first translation of On The Origin of Species into German.

References:

Bromley, R.G. 1970. Borings as trace fossils and Entobia cretacea Portlock, as an example. Geological Journal, Special Issue 3: 49–90.

Bronn, H.G. 1838. Lethaea geognostica: oder, Abbildungen und Beschreibung der für die Gebirgs-Formationen bezeichnendsten. E. Schweizerbart’s Verlagshandlung, Stuttgart, 545 pages.

Buatois, L., Wisshak, M., Wilson, M.A. and Mángano, G. 2016. Categories of architectural designs in trace fossils: A measure of ichnodisparity. Earth-Science Reviews (DOI: 10.1016/j.earscirev.2016.08.009).

Taylor, P.D. and Wilson, M.A. 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62: 1-103.

Wilson, M.A. 2007. Macroborings and the evolution of bioerosion, p. 356-367. In: Miller, W. III (ed.), Trace Fossils: Concepts, Problems, Prospects. Elsevier, Amsterdam, 611 pages.

 

Wooster’s Fossil of the Week: A naticid gastropod from the Pliocene of southern California

October 28th, 2016

polinices-galianor-sd-pliocene-1-copyThis week’s fossil comes from our teaching collection. It’s label appears to be from the late 19th Century. It is a naticid gastropod (“moon snail“) listed as Polinices galianor. That name, which I can only find in two lists and never with an author, may be a corruption of Polinices (Euspira) galianoi Dall 1909. It was collected from the Pliocene of San Diego County, California. It is preserved as both an internal mold and thin sheets of remnant original shell.

polinices-galianor-sd-pliocene-2-copyThis is a view of the underside along the axis of coiling. The hole is known as the umbilicus and is distinctive for the naticids. These snails are predatory, moving through loose sand with a very large foot and capturing shelled prey, like clams and other gastropods. They then drill a beveled hold through the shell of the prey with specialized teeth in their radulae. We’ve discussed the trace fossils they leave (Oichnus) in a previous post.

The genus Polinices was named in 1810 by Pierre Dénys de Montfort (1766–1820), a French malacologist (one who studies mollusks).

screen-shot-2016-10-22-at-11-52-46-amThe title page of de Monfort (1810).

screen-shot-2016-10-22-at-11-49-26-amThis brief paragraph is all it took in the early 19th Century to name a new taxon. The system is much more elaborate now.screen-shot-2016-10-22-at-8-20-44-pmPierre Dénys de Montfort is a tragic figure in science. First, he had the misfortune of being a French intellectual during the chaos of the French Revolution and the resulting Napoleonic dictatorship. Scientists struggled then, but after service in the revolutionary army and an apprenticeship with a geologist, de Monfort gained a position in the Jardin des Plantes, a research botanical garden in Paris. He did a massive study of mollusks, producing systematic tomes. De Monfort was a whiz at languages, so he did well as a translator after Napoleon was  finally defeated in 1815 and the Allied armies occupied Paris. Then he went off the rails. He had since 1801 championed the reports of mariners that giant cephalopods occasionally rose from the sea and attacked shipping, as shown in his above print (de Monfort, 1801, p. 256). The modern roots of the kraken! De Monfort took the idea too far, was ridiculed in the scientific community, and eventually died of starvation and alcoholism in the streets of Paris in 1820. The later discovery of giant squid salvaged his reputation a bit, but no one has yet found evidence of “le poulpe colossal”.

References:

Dall, W.H. 1909. Contributions to the Tertiary paleontology of the Pacific coast. U.S. Geological Survey Professional Paper 59. U.S. Government Printing Office, 288 pages.

de Montfort, P.D. 1801. Histoire naturelle, générale et particuliere des Mollusques, animaux sans vertèbres et á sang blanc. Volume 2. Paris, 424 pages.

de Montfort, P.D. 1810. Conchyliologie systématique, et classification méthodique de coquilles. Volume 2. Paris, 692 pages.

 

Wooster’s Pseudofossils of the Week: Artifacts in thin-sections of Ordovician limestones from southeastern Minnesota

October 21st, 2016

1bubfirstIt is always exciting to a geologist when thin-sections of curious rocks are completed and ready for view. A thin-section is a wafer of rock (30 microns thick) glues to a glass slide and examined by transmitted light through a petrographic microscope. They provide fantastic views of the mineralogy, paleontology, and structure of a rock in exquisite detail. Thin-sections are also full of mysteries since we have essentially two-dimensional slices through three-dimensional materials.

Thin-sections from the Decorah Formation samples collecting by Team Minnesota this past summer were finally available this week for study. I took the first look at slides of limestones containing ferruginous (iron-rich) ooids we gathered as part of Etienne Fang’s (’17) Independent Study. The first structures I saw were the crazy dark outlines above. What sort of fossils are these, I wondered. Could they be sponges? Odd bryozoans? Borings through the rock fabric? I was ready to post them here as mystery fossils to solicit your opinions. Now, though, they instead make a cautionary tale.

2bub730There are many of these features in a single slide from the Decorah Formation exposed at the Golden Hill outcrop near Rochester, Minnesota. Some are astonishingly complex. It then began to occur to me that these structures were too convoluted and unpredictable to actually be fossils. It also bothered me that to focus on them required to put the rest of the field out of focus. That only made sense if these oddities were in the epoxy, not the rock itself.

3buboverlapEtienne showed me how to demonstrate that these funny loops were not in the rock with this view: You can just make out the greenish lines overlapping the cut surface of this ferruginous ooid. Turns out I was excited about air bubbles in the cementing epoxy. They have nothing to do with the rock. I nearly posted my own pseudofossils.

4trio7321I held out hope, though, that these odd white objects in another thin-section of ooid-rich limestone. They appear to be ghostly outlines of ooids with a finely-textured object inside. They look like seeds with embryos within. Several are scattered through the thin-section. Another mystery fossil!

5duo7321A closer view. Strange how each internal object seems connected to an ooid on the outside, making them asymmetrical in their placements.

6single7321Strange also how once again the details of the internal object can only be seen with the rest of the slide out of focus. Yes, another artifact in the epoxy. This time we may be looking at holes left by ferruginous ooids plucked from the rock through the grinding process, pulling a patch of epoxy with them. Somehow this happened when the now-missing ooid was wedged against another. Nothing to see here, folks.

7ooid7301fAt least I can take the opportunity to show how cool Etienne’s ferruginous ooids are. Note that this one has a greenish layer midway through the cortex. It looks like the mineral chamosite to me. Spectacular detail in the lamellae, but only visible if the image is over-exposed.

8bifoliate7301hThere are plenty of real fossils in these thin-sections, of course. My favorites are these bifoliate bryozoans (lower right half) with their zooecia filled with ferruginous material. Note that the ooid above has had some of its lamellae dissolved away, probably because of some mineral diversity. Also note in the upper right another one of those crazy air bubbles.

The lesson I learn over and over: think, but then think again.

 

 

 

Wooster’s Fossil of the Week: Spiriferinid brachiopod from the Lower Carboniferous of Ohio

October 14th, 2016

syringothyris-texta-hall-1857-anterior-585Sometimes I choose a Fossil of the Week from our Invertebrate Paleontology teaching collection because students have responded to it in some way. This week’s fossil brachiopod has confused my students a bit because it is an internal mold (unusual for brachiopods in our experience) and a member of the Order Spiriferinida rather than the Order Spiriferida. (Catch that? The difference is in two letters.) It is Syringothyris texta (Hall 1857) from a local exposure of the Logan Formation (Lower Carboniferous). Above is a view of the anterior showing the medial fold and sulcus (like an anticline). This, by the way, is the largest brachiopod in our collection.

syringothyris-texta-hall-1857-posterior-585Syringothyris Winchell, 1863, is a genus within the order Spiriferinida, as noted before. This order was erected in 1994, pulling it from the more familiar Order Spiriferida. In this preservation, the spiriferinids are distinguished by a high cardinal area in the posterior (shown above). Not much higher than the spiriferids, truth be told.

syringothyris-texta-hall-1857-dorsal-585This is a view of the dorsal valve side of this internal mold. Note the absence of ribs (plicae) on the fold in the middle.

a_winchellThe geologist and paleontologist Alexander Winchell (1824-1891) named and described the genus Syringothyris. We met Winchell before in this blog as he described many common fossil taxa in the Midwest. He was born in upstate New York, a seventh-generation New Englander. In 1847 he was graduated from Wesleyan University in Connecticut. He had a varied and peripatetic career, spending most of his time as a teacher of science. He first taught in New Jersey, New York and Alabama, staying a short time in each place. He founded the Mesopotamia Female Seminary in Eutaw, Alabama, and became president (briefly) of Masonic University in Selma. In 1854, Winchell was appointed professor of physics and civil engineering at the University of Michigan, a position that soon became geology and paleontology. Five years later he became the state geologist of Michigan, a job characterized by an apparently difficult relationship with his superiors. In 1872 he left Michigan to be chancellor of Syracuse University, lasting only two years. Next he was a professor of geology and zoology at Vanderbilt University, a position he was forced to resign from in 1878 due to his unbiblical views of evolution. Winchell then returned to the University of Michigan, again as a professor of geology and paleontology. There is where he died.

Winchell’s views on evolution were complicated by his religiosity, and his religious life was made difficult by evolution. He developed a kind of transcendental Darwinism in which selection was reduced to inflexible laws from the Creator, a view we would today call Intelligent Design. He then confused it all by writing a popular book called Preadamites, published in 1880. The darker races, he said, lived in Europe and Asia before Adam. Adam and the subsequent “Noachites” were derived from Negroes, according to Winchell, advancing steadily in intellectual development and whiteness while the black race and other Preadamites were left behind. This work is profoundly racist and pseudoscientific, despite the Darwinian gloss he attempted to paint over it.

a-screen-shot-2016-10-10-at-8-49-42-pmb-screen-shot-2016-10-10-at-8-57-04-pmFrontispiece of Winchell (1880).

References:

Bork, K.B. and Malcuit, R.J. 1979. Paleoenvironments of the Cuyahoga and Logan Formations (Mississippian) of central Ohio. Geological Society of America Bulletin 90: 89–113.

Vörös, A., Kocsis, Á.T. and Pálfy, J. 2016. Demise of the last two spire-bearing brachiopod orders (Spiriferinida and Athyridida) at the Toarcian (Early Jurassic) extinction event. Palaeogeography, Palaeoclimatology, Palaeoecology 457: 233-241.

Winchell, A. 1863. Descriptions of FOSSILS from the Yellow Sandstones lying beneath the “Burlington Limestone,” at Burlington, Iowa. Academy of Natural Sciences of Philadelphia, Proceedings, Ser. 2, vol. 7: 2-25.

Winchell, A. 1880. Preadamites; or a demonstration of the existence of men before Adam. Chicago, S.C. Griggs and Company; 500 p.

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