A new paper has appeared: A rugose coral – bryozoan association from the Lower Devonian of NW Spain.

June 14th, 2019

I’m proud to be an author with my two Spanish colleagues, Consuelo Sendino and Juan Luis Suárez Andrés, of a paper just out in the latest issue of Palaeogeography, Palaeoclimatology, Palaeoecology (we call it “Palaeo-cubed”). I’ll let the abstract tell the story (with some embedded links):

“A new rugose coralcystoporate bryozoan association is here described from the Devonian of NW Spain. This is the first evidence of intergrowths between Devonian rugose corals and bryozoans. In this case bryozoans provided a suitable substrate for the settlement of corals, which were subsequently encrusted by the bryozoans. The hypothesis of intergrowth between living organisms is supported by the absence of encrustation of the rugose coral calices by the cystoporates. We suggest that the association was specific and developed through chemical mediation. This symbiosis was facultative for the bryozoans but likely not for the corals. The association provided the bryozoan host with additional substrate for encrustation as well as protection from various predators, and it allowed the rugose corals to grow in a muddy environment and benefit from the feeding currents of the bryozoans.”

The above images show some of these specimens of corals intergrown with bryozoans. The caption from Figure 2: Intergrowth of fistuliporid bryozoans and rugose corals from the Aguión Formation of Asturias, NW Spain. A. General view of DGO12902. B. General view of MMAGE0033. C. Detail of the corallite, MMAGE0032. D. Magnified corallite of the right side, MMAGE0033.

This cartoon from the paper shows the process in which a coral larva (planula) lands on a living bryozoan, somehow survives the encounter, and then the coral grows together with the surrounding bryozoan colony. The fun part is sorting out the biological and evolutionary context of this relationship.

I thank my colleagues Consuelo and Juan for inviting me into this project. I learned a lot that will be applied to similar intergrowing situations in the fossil record.

Sendino, C., Suárez Andrés, J.L. and Wilson, M.A. 2019. A rugose coral – bryozoan association from the Lower Devonian of NW Spain. Palaeogeography, Palaeoclimatology, Palaeoecology 530: 271-280.

New paper on crinoids of the Kalana Lagerstätte (Early Silurian) of central Estonia

May 14th, 2019

Bill Ausich (The Ohio State University), Oive Tinn (University of Tartu) have a paper that has just appeared:

Ausich, W.I., Wilson, M.A. and Tinn, O. 2019. Kalana Lagerstätte crinoids: Early Silurian (Llandovery) of central Estonia. Journal of Paleontology doi.org/10.1017/jpa.2019.27

It was an absolutely delightful project that was thoroughly documented in this blog. Last summer Bill and I traveled to Tartu, Estonia, to work with Oive on describing the extraordinary crinoids of the Silurian Kalana Lagerstätte. A Lagerstätte is a sedimentary deposit with exceptional fossil preservation. It is a privilege as a paleontologist to work on one. As you can see from the images, the crinoids here are well preserved indeed. I’ll let the paper’s abstract tell the story:

Abstract.—The Kalana Lagerstätte of early Aeronian (Llandovery, Silurian) age in central Estonia preserves a diverse shallow marine biota dominated by non-calcified algae. This soft-tissue flora and decalcified and calcified crinoids are preserved in situ in a lens of microlaminated, dolomitized micrite interbedded in a sequence of dolomitized packstones and wackestones. Although the Lagerstätte is dominated by non-calcified algae, crinoids (together with brachiopods and gastropods) are among the most common organisms that were originally comprised of a carbonate skeleton. Two new crinoids are described from this unit, Kalanacrinus mastikae n. gen. n. sp. (large camerate) and Tartucrinus kalanaensis n. gen. n. sp. (small disparid). Interestingly, these two crinoids display contrasting preservation, with the more common large camerate preserved primarily as a decalcified organic residue, whereas the smaller disparid is preserved primarily in calcite. Preservation was assessed using elemental mapping of C, Ca, S, and Si. Columns have the highest portion of Ca, once living soft tissue is indicated by C, S was dispersed as pyrite or associated with organics, and Si is probably associated with clay minerals in the matrix. This new fauna increases our understanding of the crinoid radiation on Baltica following Late Ordovician extinctions.

The top image and that above shows the new crinoid Kalanacrinus mastikae. Look at those gorgeous arms and the carbon films in the calyx that may represent internal organs. The species is named in recognition of Viirika Mastik, an Estonian graduate student who helped us in innumerable ways, and she was very patient with the sometimes clueless Americans! The genus, of course, is named for the deposit. (Scale bar is 5.0 mm.)

Here is another specimen of Kalanacrinus mastikae. Note the small angular, twiggy fossil below the calyx. I think it may be a green alga similar to the modern Hydrodictyon but marine and with larger cells.

Say hello to the new crinoid Tartucrinus kalanaensis. It’s pretty obvious how we came up with these names. Note again a carbon film in the calyx that may be from internal organs, possibly the anal sac. (Scale bar is 5.0 mm.)

The location and stratigraphy of the Kalana Quarry.

Several slabs of Kalana material. What a joy it was to study them for long, uninterrupted days.

The paleo lab at the University of Tartu, with Bill working in the background.

I loved this brand new Leica photomicroscope (model S9i).

Oive does excellent geochemistry, so she handled the elemental mapping. This example shows a close view of a Kalana crinoid column, with the elements C, Ca, S, and Si mapped. As stated in the abstract, columns have the highest portion of Ca, once living soft tissue is indicated by C, S was dispersed as pyrite or associated with organics, and Si is probably associated with clay minerals in the matrix.

Thank you to our excellent Estonian colleagues!

From the left is Oive Tinn, Mare Isakar, Bill, and Viirika Mastik.

New paper: Borings from the Silurian of Sweden — possibly the oldest deep-boring bivalves

April 27th, 2019

It was a delight to be a junior member of the team that produced this recent paper:

Claussen, A.L., Munnecke, A., Wilson, M.A. and Oswald, I. 2019. The oldest deep boring bivalves? Evidence from the Silurian of Gotland (Sweden). Facies 65: 26. https://doi.org/10.1007/s10347-019-0570-7

This may be the first paper for me where I’ve not yet met my co-authors. They are all from the GeoZentrum Nordbayern, Fachgruppe Paläoumwelt, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany. This is where our recent graduate William Harrison is a graduate student. (He is clearly having a wonderful time there!)

Our team leader was the remarkable Lene Claussen. She did a prodigious amount of working and thinking for this study, which combines many of paleontology’s most recent tools, from isotopic analysis to micro-computed tomography. The abstract give us a synopsis of the story —

Abstract: Compared to modern counterparts, bioerosion is rare in Paleozoic reefs, especially macro-bioerosion. The unique and enigmatic Silurian reefs from Gotland (Sweden), composed of bryozoans and microbial laminates, show evidence of a large amount of bioerosion. The samples contain Trypanites trace fossils, as well as a large number of undescribed macroborings. Small articulated bivalve shells are preserved in some of these macroborings, identified from thin-sections. Three-dimensional images from micro-computed tomography (microCT) reveal an additional bivalve, which is occupying a bioerosion trace. This specimen is possibly contained in a different boring that can be classified as possibly clavate-shaped. Furthermore, evidence of nestling, such as a subsequent modification of the ichnofossils, the presence of bivalves that are much smaller than the trace, or the presence of additional specimens, is missing; therefore, it is most likely that the bivalves made the borings. This is evidence for the existence of deep-boring bivalves in the Silurian.

Top image is from Figure 3: Bioerosion traces from Nors Stenbrott, boreholes with bivalve shells in thin-section; a lateral cut through a bivalve shell (sample P3); b lateral cut through a bivalve shell (sample P13B).

From Figure 6: Processed three-dimensional microCT images of different boring traces from Nors Stenbrott, Trypanites borings in blue and the unknown ichnofossil in green; a all contained boreholes from sample SNS1; b all contained boreholes from sample Z9A, boring with bivalve with arrow.

I learned a great deal from this study and my new colleagues, especially about new techniques and the surprises they can reveal. Thank you, Lene and crew.

A free day spent geologically in southwestern Utah

March 19th, 2019

Hurricane, Utah — Team Jurassic Utah finished its fieldwork two days ahead of schedule because I hadn’t calculated just how efficient it is to have Dr. Shelley Judge as a member. Twice as fast, twice as good. We thus were able to have yesterday in Zion National Park and today in the St. George area. With the perfect weather this was the place to be an exploratory geologist.

We first drove down a long dirt road to a site in Warner Valley which has exposed Lower Jurassic dinosaur tracks.

Here I’m photographing the best theropod dinosaur track with Anna’s help. (Image by Nick Wiesenberg.)

Here’s the nice footprint. Notice how the mud was squeezed up between the toes as the theropod sloshed its way across a floodplain. This shape of dinosaur track is given the trace fossil name Eubrontes.

The footprint layer in Warner Valley is in the lower part of the Kayenta Formation (Lower Jurassic).

We next visited a beautiful neighborhood in Bloomington which has in its midst an excellent set of Indian petroglyphs. The Bloomington Petroglyph Park is tiny, but well worth the drive.

Anna is here photographing the largest surface of petroglyphs.

Most of the petroglyphs were made by carefully scraping away a layer of desert varnish on light-colored sandstone blocks. Humans and animals are easily recognizable; other symbols are mysterious.

After lunch we went to the Dino Cliffs site in the Red Cliffs Desert Reserve. We had a nice hike through exposures of the Kayenta Formation. (The top image of this post is also from this area.) We found the dinosaur tracks, but their poor preservation did not merit a photo.

Finally we went to the old 19th century mining town of Silver Reef. The museum was closed, but we were able to walk around the old buildings still preserved, along with antique mining equipment on display.

Most of the old town is long gone, leaving some evocative ruins.

The wildflowers today were uncommon. They included the classic Indian Paintbrush (Castilleja angustifolia) …

… and significant numbers of Spectacle Pod (Dimorphocarpa wislizeni). Thank you to my Mother Corinne Wilson for the identification!


Last day of fieldwork for Team Jurassic Utah 2019

March 17th, 2019

Hurricane, Utah — Our expedition had its final official fieldwork today, which we marked with a group photo overlooking the magnificent Snow Canyon. See the end of this post for alternative flag group images!

Tomorrow the group visits Zion National Park. The next day will be spent exploring the local geology and culture, and then it is packing up our samples for shipment to Wooster. Today, though, The Carmel Formation calls one last time!

We returned to the extensive Carmel outcrops in Dammeron Valley, looking at the northernmost extension of the ooid shoal facies. Here is our short shoal section at Dammeron Valley North (DVN), which consists entirely of cross-bedded limestones placed in four subunits (A-D).

This exposure weathered into many loose slabs from the upper subunit D. The trace fossils are well preserved, including this Planolites with rare branching. It is convex hyporelief.

The traces here include a sinuous bilobed Gyrochorte and a thick trace in the left foreground I can’t yet identify. Anna found this rippled slab.

This big trace Evan found is almost certainly Rhizocorallium.

We originally thought that our section today (DVN) was an extension 638 meters to the west of the DV shoal unit. Nick and Shelley did excellent stratigraphic detective work to show that DVN is about 15 meters below the DV measured unit. We thus found the eastern equivalent of DVN at the DV location, measured and sampled it. For now we call it “DVN at DV”. More detail than anyone wants to know, but these blog entries are also a kind of field notes!

The traditional Wooster flag group photo as taken by Shelley.

The flag group photo taken by Nick.

East of Zion

March 16th, 2019

Hurricane, Utah — Today Team Jurassic Utah traveled to Mt. Carmel Junction, east of Zion National Park, to examine the extensive outcrops of the Carmel Formation in the region. The most famous location is in Mt. Carmel Junction itself (MCJ: N 37.22521°, W 112.68095°). It is this crinoid-rich limestone that is reported to be the youngest encrinite in the geological record.

Anna and I measured a two-meter column in this unit to collect samples for thin-section analysis. Four subunits (A-D) start at the bottom of the ruler here.

This is the base of subunit D. It is full of the star-shaped columnals of the crinoid Isocrinus nicoleti. It is one of only three Jurassic crinoid species in North America.

Fieldwork! Love it. Photo by Nick.

Shelley again measured cross-beds to determine current directions here. This was a complicated task because at least three joint sets intersect in these rocks.

Lunch along the Virgin River. Photo by Nick.

After lunch we went just a bit south of Mt. Carmel Junction to examine a Carmel Formation outcrop that looked superficially like it would be identical to the previous unit. We call the place Carmel Cove (CC: N 37.21548°, W 112.68215°). Turns out the limestone here is very different: no crinoids, no ooids, and relatively abundant bivalves. Amazing variability in sections within sight of each other.


Team Jurassic Utah endures polar conditions

March 13th, 2019

Hurricane, Utah — Well, maybe not fully polar, but it was very cold and windy in southern Utah today. Our glove-less fingers were numb, and the bitter gusts penetrated our pitiful parkas. We collected some samples but put off measuring columns (which inevitably requires working fingers) for a warmer day.

Our mission, as before, was to find ooid-rich units for Anna and mollusk fossils for Evan. We were at the “Water Tank” locality (C/W-751) of last year. It is our least attractive site, having a blue water tower and all.

The bivalves here are numerous and diverse, but only in a narrow horizon (so far). They are certainly more species-rich than at yesterday’s Eagle Mountain Ranch site.Anna found a cross-bedded ooid-rich limestone along the road to the water tank. We will be back to measure and sample this section in detail.For lunch we went to nearby Snow Canyon State Park, where we hoped it would be a tad warmer. (It was — barely.) The sun was out and the colors vivid. This is the Petrified Dunes walk. All you see here is the glorious Navajo Sandstone (Jurassic — beneath the Temple Cap and Carmel Formations).I was entranced by the Moqui Marbles, a kind of iron oxide concretion that weathers out of the Navajo Sandstone. They accumulate in large numbers on the flat surfaces here.

Nick with Moqui Marbles eroded out of the Navajo.Here are Moqui Marbles in place in cross-beds of the Navajo. (Guess whose legs are the scale.) These concretions are diagenetic, forming in the sandstone long after deposition. You can read the latest ideas on their formation in this Moqui Marbles article.

The cold, cold group in Snow Canyon. Image by Shelley.

A productive first day for Wooster Geologists in Utah

March 12th, 2019

Hurricane, Utah — Team Jurassic Utah 2019 started its fieldwork on a cloudy March day with a bit of a chill and some light rain, but it didn’t rain again and the cooler temperatures were comfortable. We worked on the Eagle Mountain Ranch site (C/W-142) looking for ooids (Anna’s Independent Study project) and mollusks (Evan’s I.S. work). Thank you again to ranch owners Hyrum and Gail Smith for permission to work on this important outcrop. (Photo by Nick Wiesenberg.)

Anna and Evan are here describing a critical meter-thick resistant limestone in an otherwise clay-dominated portion of the Co-Op Creek Limestone Member of the Carmel Formation. We think it represents a normal marine incursion into an otherwise restricted lagoonal environment. This is where most of the fossils and ooids at Location C/W-142 come from.

The base of the unit has these very nice wave ripples indicating shallow water.

Nick and Shelley did excellent work measuring the 39 meters of our Carmel interval. They used a Jacob’s Staff with a Brunton compass attached to account for the rock attitude (strike and dip).

Shelley and Nick are the colored dots at the top of our Eagle Mountain Ranch section. They sampled the top of the Carmel here, finding it to be a brecciated limestone below an unconformity with the overlying Upper Cretaceous Iron Springs Formation. The grey wedge of rock thickening to the left is a mysterious claystone. With the breccia discover, we at least know it is above the Carmel.

The team at lunch overlooking the Eagle Mountain Ranch. The slope seemed much steeper than this! (Photo by Nick.)

I know it doesn’t look like much, but Evan found this internal mold of an ammonite at C/W-142. It is the first I’ve seen in the Carmel. (Later Andrew Milner will show us another ammonite from the same location.)

This is the venter view. Definite ammonite, but unidentifiable beyond this!

On the walk back from our main locality, we examined a laminated micritic part of the Co-Op Creek Limestone Member (Location Strom-mat at N 37.30882°, W 113.73883°). This is just below our main section of interest. (Photo by Nick.)

Anna is photographing close details of this unit.

The laminations are spectacular, apparently representing microbial mats. Another future Independent Study project!

Finally, on our drive back to Hurricane we checked out our access to the classic oyster ball localities on the west side of the Santa Clara River. Here is an image of the bridge last year.

The bridge today! A flood destroyed it last month. No way we’re crossing here. Time to explore other options.

Team Jurassic Utah at the Gunlock Reservoir, with the fantastic Carmel Formation in the background.

Bringing three new Silurian bryozoan species into the world

February 10th, 2019

I love being part of the scientific process of naming new organisms and placing them into the grand narrative that is the history of life. It is a kind of rescue — retrieving species from oblivion by giving them identities. Carolus Linnaeus, the father of taxonomy, said it well:

The first step in wisdom is to know the things themselves; this notion consists in having a true idea of the objects; objects are distinguished and known by classifying them methodically and giving them appropriate names. Therefore, classification and name-giving will be the foundation of our science.

The bryozoans described in this post are from a project led by my very accomplished bryozoologist friend Andrej Ernst at the University of Hamburg, Germany (above). In the summer of 2015, Andrej and I met up with our colleague Carl Brett (University of Cincinnati) to collect bryozoans from the Lower Silurian (Aeronian) of western New York. My fieldwork was supported by a grant from the Luce Fund at The College of Wooster. We had a very productive time and saw much geology and paleontology, as you can see from these August 2015 blog posts. That fieldwork was followed by Andrej’s prodigious lab work with the bryozoans. The results have now appeared in the Journal of Paleontology.

The abstract: Thirteen bryozoan species are described from the Brewer Dock (Hickory Corners) Member of the Reynales Formation (lower Silurian, Aeronian) at the locality Hickory Corners in western New York, USA. Three species are new: trepostomes Homotrypa niagarensis n. sp. and Leioclema adsuetum n. sp. and the rhabdomesine cryptostome Moyerella parva n. sp. Only one species, Hennigopora apta Perry and Hattin, 1960, developed obligatory encrusting colonies whereas the others produced erect ramose colonies of various thicknesses and shapes: cylindrical, branched, and lenticular. Bryozoans display high abundance and richness within the rock. This fauna is characteristic of a moderately agitated environment with a stable substrate. The identified species reveal paleobiogeographic connections to other Silurian localities of New York as well as Ohio and Indiana (USA) and Anticosti (Canada).

The top photo in this post is one of the new bryozoans, the trepostome Homotrypa niagarensis. The images are from Figure 8, with the caption: (2) branch oblique section, holotype SMF 23.470; (3) rock thin section with transverse and oblique sections of branches, holotype SMF 23.472; scale bars are 3 mm and 5 mm respectively.

Above is the new trepostome Leioclema adsuetum. The image is from Figure 10, with the caption: (1) longitudinal section of exozone showing autozooecia, mesozooecia, and acanthostyles, paratype SMF 23.553; scale bar is 0.5 mm.

This is the third new species, the cryptostome Moyerella parva. The images are from Figure 11, with the caption: (3) longitudinal section of a colony segment with a pointed base and widened proximal part showing medial axis and autozooecia, holotype SMF 23.559; (4) tangential section showing autozooecial apertures, tubules, and tectitozooecia, holotype SMF 23.559; scale bars are 0.5 mm and 0.2 mm respectively.

The paper is about more than these new species, of course. There are other bryozoans assessed, and Carl Brett’s stratigraphy section is magnificent and a new resource for the area. The new taxa, though, are worth celebrating by themselves.

Thank you to Andrej and Carl for being such good colleagues. I hope we return to the Silurian of western New York for more work.


Ernst, A., Brett, C.E. and Wilson, M.A., 2019. Bryozoan fauna from the Reynales Formation (lower Silurian, Aeronian) of New York, USA. Journal of Paleontology, doi.org/10.1017/jpa.2018.101.

Conulariid and trepostome bryozoan symbiosis in the Upper Ordovician of Estonia

January 22nd, 2019

A new paper is just out in which all the characters have been covered previously in this blog, but not as parts of a single story. It describes an interprets the relationship between the mysterious conulariids and trepostome bryozoans in the Katian and Sandbian (Upper Ordovician) of northern Estonia. The authors have all made appearance here, including lead author Olev Vinn (Institute of Ecology and Earth Sciences, University of Tartu, Estonia). Andrej Ernst (Institut für Geologie, Universität Hamburg, Germany), myself, and Ursula Toom (Institute of Geology, Tallinn University of Technology, Estonia). It was a fun team to work on, and Olev led it masterfully.

There are numerous trepostome bryozoans in the Upper Ordovician of Estonia that grew up and around the bases of conulariids, which are extinct cnidarians. This is, in fact, an example of bryoimmuration as covered in my last post. The puzzle is what was the relationship between these two groups. Were the conulariids parasites on the bryozoans? Did they gain protection from predators by embedment in the bryozoan calcitic skeleton? Were the bryozoans prime real estate for the conulariids because they were hard substrate islands on a muddy seafloor? We think the answers are probably yes to all these questions.

The top composite of images is Figure 3 in the paper. The caption: A, Two conulariids Climacoconus bottnicus (Holm, 1893) in Diplotrypa bicornis (Eichwald, 1829) from Haljala Regional Stage, northern Estonia, note the slightly elevated apertures of conulariids (GIT 720-4). B, Longitudinal section of Diplotrypa abnormis (Modzalevskaya, 1953) with conulariid Climacoconus bottnicus (Holm, 1893) (GIT 537-1822) from Haljala Regional Stage, northern Estonia. C, Longitudinal section of completely embedded Climacoconus bottnicus (Holm, 1893) in Esthoniopora communis (GIT 537-1656) from Haljala Regional Stage, northern Estonia. D, Conulariid in Mesotrypa expressa Bassler, 1911 from Oandu Regional Stage, northern Estonia; note the depression around the conulariid’s aperture (GIT 770-7). E, Conulariid in Mesotrypa expressa Bassler, 1911 from Oandu regional Stage, northern Estonia; note the malformation of a zooid near the aperture of the conulariid (GIT 770-92). F, Conulariid in Esthoniopora subsphaerica from Rakvere Regional Stage, northern Estonia; note the strongly elevated aperture of the conulariid (GIT 537-1760).

This work is another product of Wooster’s generous research leaves program that has supported many trips to Estonia.


Vinn, O., Ernst, A., Wilson, M.A., and Toom, U. 2019. Symbiosis of conulariids with trepostome bryozoans in the Upper Ordovician of Estonia (Baltica). Palaeogeography, Palaeoclimatology, Palaeoecology 518: 89-96.

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