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.

Reference:

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.

Reference:

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.

New paper on bryoimmuration and taphonomic engineering

January 12th, 2019

I’m pleased to link to a new paper that has just appeared in the journal Lethaia. My wonderful coauthors are Caroline Buttler (National Museum Wales) and Paul Taylor (Natural History Museum, London). The paper explores the role calcitic bryozoans play in preserving molds of aragonitic shells, a process we call bryoimmuration. In the image above we have two views of a single specimen from the Cincinnatian (Upper Ordovician) of the Cincinnati, Ohio, region. It is a trepostome bryozoan that encrusted the exterior of a bivalve shell. The bivalve shell was aragonitic and thus dissolved away during diagenesis. The bryozoan skeleton is calcite, a mineral that does not dissolve as easily as its cousin aragonite. The surviving bryozoan skeleton thus preserved our only record of the now-dissolved bivalve shell. The larger concept of one group of organisms affecting the preservation of another we call taphonomic engineering. Below are cross-sections of these bryoimmuring bryozoans, with the original caption.

Fig. 3. Acetate peels of bryoimmuring bryozoans cut perpendicular to basal growth surface (longitudinal); all from the Upper Whitewater Formation (Katian) near Richmond, Indiana (locality as in Fig. 2). A, heterotrypid bryozoan that grew across the ribs of an ambonychid bivalve. Note the thin zooecial walls in the early fast-growing stage, later thickening upwards (CW‐148‐92). B, very thin sheet of a trepostome bryozoan that encrusted an ambonychid bivalve (CW‐148‐93). This bryozoan did not develop an exozone and is thus impossible to identify. C, heterotrypid bryozoan that developed a thick exozone while growing on an ambonychid bivalve shell (CW‐148‐94). The shell later dissolved and sediment took its place. D, multilaminar growth of a heterotrypid bryozoan on an ambonychid bivalve (CW‐148‐95). The bryozoan colony overgrew itself.

This research was supported by an award from the Henry Luce III Fund for Distinguished Scholarship at The College of Wooster. Nick Wiesenberg helped with the fieldwork. It was a fun project.

Wooster’s Invertebrate Paleontology class at work

September 18th, 2018

Wooster, Ohio — The Invertebrate Paleontology class at Wooster set to work this afternoon on the excellent fossils they collected at the beginning of last week. They had already washed them carefully, using soft brushes and soap, and now were learning how to trim them down with our faithful basement rock saw. Grant Holter is seen above doing his very first cut. All the specimens are from a single outcrop of the Upper Whitewater Formation (Upper Ordovician, Katian) just south of Richmond, Indiana.

The spinning steel blade has industrial diamonds embedded in its periphery, which grind quickly through our soft limestones. The blade and rock are continually sprayed with water to keep the blade from overheating, lubricate the cut, and to capture the dust. The newbies to our saw learned fast.

Each student has two trays of specimens, which are right now in their raw, unprepared and unlabelled state. Julia Pearson examines her very full trays. Juwan Shabazz is behind her.

A closer look at Julia’s treasures.

An even closer view. We can easily now identify abundant brachiopods, bryozoans, and rugose corals — the big three groups.

Finally for today the paleo students learned how to label their specimens using water-soluble white glue and printed paper tags, a technique I learned at the University of California Museum of Paleontology.

Next week the class will use the saws, grinders, polishing plates and hydrochloric acid to make acetate peels. This is my favorite paleo process!

2018 Invertebrate Paleontology field trip — with the Ghost of Gordon

September 9th, 2018

The Invertebrate Paleontology class at Wooster had its annual field trip today to the Upper Ordovician (Katian) Cincinnati Group (Upper Whitewater Formation) in eastern Indiana. The weather looked terrible as the remnant of Tropical Storm Gordon worked its way into the Great Lakes region. Three to five inches of rain were forecast for our field area just south of Richmond, Indiana (locality C/W-148). For all I know, that massive amount of rain actually fell today — but not while we were there! As you can see above, we collected treasures in the dry. In fact, the specimens were nicely washed for us, with the fossils standing out better than I’ve ever seen.

Here’s a random image of the rubbly limestone we examined. Count the bryoimmurations! This is perfect material for beginning paleontology students. Each one made a representative collection to clean, prepare and interpret in our cozy Wooster lab the rest of the semester.

We’ve certainly had better weather here in past years, but I’m not complaining about today. We slipped by a ghost.

Wooster and Ohio State Paleontologists in Tallinn, Estonia

August 8th, 2018

Tallinn, Estonia — This morning Bill Ausich (Ohio State University) took the bus from Tartu to Tallinn to finish one more research task and then prepare for the long journey home. Above is the view from my hotel room towards the Old City section of Tallinn.

After getting settled, we visited Ursula Toom at the Department of Geology, Tallinn University of Technology. She and Bill (above) exchanged crinoids, and then Ursula discussed with me a wide variety of Ordovician borings as part of her dissertation work.

This is a small part of the various mystery specimens Ursula shared with me. There are some fantastic undescribed borings in this lot.

Afterwards Bill and I had an early evening dinner in the Old City, beautiful in the setting sun.

Our research in Estonia is done! Tomorrow we pack up and then walk around Tallinn taking in the sights and culture. On Friday we fly home. I hope to describe the results of our work soon in this blog.

Last day at the Tartu Natural History Museum, and a visit to a grim museum

August 7th, 2018

Tartu, Estonia — Bill Ausich and I started our last full day in this city at the University of Tartu Natural History Museum, finishing our work with the marvelous Mare Isakar, pictured above. Mare quickly found the specimens we needed, and many others she knew we would find interesting. She did nearly instant registration of specimens, greatly speeding up our taxonomic progress.

We finished photographing museum specimens for our future reference and possible publications. Bill concentrated on Silurian crinoids and I worked on the Ordovician rhombiferan Echinosphaerites.

This is one of Öpik’s Echinosphaerites aurantium specimens. Two roundish encrusting brachiopods are visible, along with sheet-like bryozoans. Shockingly, there are gouges in the bryozoans as if someone tried to scrape them off!

Most of the rhombiferans are filled with sediment and/or calcite crystals, but Bill found this hollow one in the collections. Note that it was still able to resist sedimentary compaction. Also note the bryozoans on the broken edge.

This broken specimen shows sediment in the bottom of the skeleton and crystals in the top half. This is known as a geopetal structure where the sediment shows what was the lower part of the skeleton when it was filled. Here’s another example.

Mare found even more specimens of Echinosphaerites today, so there is much to do on a later trip! Thank you again to Mare Isakar and our other friends in Tartu. Tomorrow we travel to Tallinn for a bit more work before heading home on Friday.

And now for something darker — the KGB Cells Museum in Tartu. It is a horrifying place of pain, anguish and hopelessness, yet today is surrounded by a vibrant, free city and country. This museum, in an actual KGB prison, is both disturbing and ultimately inspiring. It is a history we avoid at our peril.

A cell door near the entrance to this basement complex of “the grey house”. These dungeons were used by the Soviet secret police for detention, torture and executions in the 1940s and 1950s. For a brief interval (1941-1944) the Nazis took over and did the same beastly activities. The victims were almost entirely Estonians.

A hallway of cells. The exhibits inside the rooms include many Soviet artifacts, along with stories of Estonian resistance.

A KGB mannikin at the end of a hallway. A sound track of a harsh Russian voice plays in a loop here, along with inevitable screams and moans. The brutality of the place is quite evident enough, thank you.

Finally, before you leave, why not dress up as a Soviet KGB officer and pose with Stalin? I don’t understand why anyone would do such a thing, especially in such a tragic space.

Tomorrow it is back to science as Bill and I take the bus to Tallinn. The countryside of free Estonia is beautiful.

Last day in the University of Tartu Geology Department — and a great garden party

August 6th, 2018

Tartu, Estonia — As a sign we’re near the end of our work in Tartu, there are no crinoids in this post. Instead, above is an Ordovician bryozoan from Estonia that encrusted the aragonitic shell of a nautiloid. The aragonite dissolved away, giving my favorite underside view of a bryozoan attachment from its ancestrula. We’ve seen this more than once in this blog. The bonus here are the just-visible chains of little crystalline teardrops across the surface.

These are the zooids of the cyclostome bryozoan Corynotrypa. They are encrusted right-side-up, meaning that they grew across the exposed attachment surface of the big bryozoan. The nautiloid shell thus dissolved between the two encrusting events — very early on the seafloor. Classic calcite sea dynamics.

After sorting out the specimens used in our crinoid studies, and doing some last microphotography, we finished our work for this season at the University of Tartu Department of Geology. A small and happy garden party followed.

Bill Ausich and some of our Estonian colleagues and friends. From the left is Oive Tinn, Mare Isakar, Bill, and Viirika Mastik. Great conversations. It actually got a little chilly outside, so we ended in Oive’s house (see below).

Sunday at the University of Tartu Natural History Museum — this time as tourists

August 5th, 2018

Tartu, Estonia — Bill Ausich and I returned to the Natural History Museum today to tour the public exhibits. It was hard to not make it into a study trip, though, for our research. I suppose since our “work” is so enjoyable it is difficult to separate it from a holiday. Above, for example, is a display of our favorite rhombiferan, Echinosphaerites aurantium of the Estonian Upper Ordovician.

There is a display about the Kalana Lagerstätte that we are studying.

Here is the museum description of the Lagerstätte.

And a close-up of some crinoids (“meriliilia”, sea lilies) from the Kalana.

It is a fun museum with a very thorough geology section, including meteorites you can touch (a favorite of mine). It has what is now an old-fashioned style of emphasizing actual specimens that Bill and I appreciated. There is a large biology section with much taxidermy and mounted skeletons. One of the featured exhibits is a rare “rat king” (see below), which you must look up!

Back to work in the University of Tartu Geology Department

August 3rd, 2018

Tartu, Estonia — Today Bill Ausich and I returned to the geology lab on the university campus to continue our work on the Kalana Lagerstätte crinoids. There is Bill above working on specimens.

I spent most of the day working with this beautiful Leica photomicroscope (model S9i). It is the most intuitive photomicroscope I have ever seen. The images are superb. I want.

Here I am at the microphotography station, looking wistfully outside.

We don’t have anything new to report today, so here’s an image of one of the best Kalana crinoids.

This is my favorite specimen because it is squashed in a way that separated the calyx plates to make them easier to see.

The calyx is on the left side of this specimen. The pinnules from the arms are preserved so well here they look like hair. Note the small angular fossil just below the crinoid on the right. These are common in the Lagerstätte, often appearing to be attached to crinoids. We think they may be green algae, possibly like the modern Hydrodictyon but marine — and with larger cells. Another mystery in this fossil assemblage.

We’ve now completed a week in Tartu. The Kalana crinoid project has gone especially well. Thank you to graduate student Viirika Mastik who collected most of the Kalana crinoids, and to her supervisor Oive Tinn. They have helped us immensely in the lab.

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