Wooster’s Fossils of the Week: Ordovician cryptostome bryozoans from southern Ohio

September 23rd, 2016

waynesville-cryptostomesA short entry this week because the annual meetings of the Geological Society of America and Paleontological Society begin this weekend in Denver. (Wooster is sending 17 students this year. Seventeen! A record for us.)

The above image is a detail from a slab of limestone collected from the Waynesville Formation (Upper Ordovician, Katian) on a class field trip earlier this month to Caesar Creek, Warren County, Ohio.  The stick-like fossils are mostly cryptostome bryozoans generally aligned by the last of some ancient water current. Cryptostomes are small and fussy  bryozoans, and thus hard to work with. There hasn’t been a significant overview of Ohio Ordovician cryptostomes for quite awhile, so I suspect there is much new to learn about them.

The following posts will be from Denver!

Wooster’s Fossils of the Week: New Early Silurian crinoids from Estonia

September 16th, 2016

1 Hilliste crinoidsIt has been a good year for new fossil taxa on this blog. I’m pleased to present a fauna of Early Silurian crinoids from the Hilliste Formation (Rhuddanian) exposed on Hiiumaa Island, western Estonia. They are described in a paper that has just appeared in the Journal of Paleontology (early view) written by that master of Silurian crinoids, Bill Ausich of Ohio State University, and me, his apprentice.

Here’s the simplified caption for the above composite image: Rhuddanian crinoids from western Estonia: (1) Bedding surface comprised primarily of crinoid columnals and pluricolumnals; (2) Radial circlet of an unrecognizable calceocrinid; (3) Basal circlet of an unrecognizable calceocrinid; (4) Holdfast A: Virgate radices anchored in coarse skeletal debris; (5) Holdfast D: Simple discoidal holdfast cemented to a bryozoan; (6, 7, 8) Hiiumaacrinus vinni n. gen. and n. sp.: 6, D-ray lateral view of calyx, 7, E-ray lateral view of calyx, 8, basal view of calyx; (9) Holdfast B: Dendritic holdfast in coarse skeletal debris; (10) Eomyelodactylus sp. columnal; (11) Holdfast C: Simple discoidal holdfast cemented to a tabulate coral; (12) Two examples of Holdfast E: Stoloniferous holdfasts cemented to a tabulate coral; (13) Protaxocrinus estoniensis n. sp. lateral view of partial crown, top of radial plate indicated by line.

Here is the abstract: “Rhuddanian crinoid faunas are poorly known globally, making this new fauna from the Hilliste Formation of western Estonian especially significant. The Hilliste fauna is the oldest Silurian fauna known from the Baltica paleocontinent, thus this is the first example of the crinoid recovery fauna after the Late Ordovician mass extinction. Hiiumaacrinus vinni n. gen. n. sp., Protaxocrinus estoniensis n. sp., Eomyelodactylus sp., calceocrinids, and five holdfast types are reported here. Although the fauna has relatively few taxa, it is among the most diverse Rhuddanian faunas known. Similar to other Rhuddanian crinoid faunas elsewhere, the Hilliste crinoid fauna contains crinoids belonging the Dimerocrinitidae, Taxocrinidae, Calceocrinidae, and Myelodactylidae; most elements of the new fauna are quite small, perhaps indicative of the Lilliput Effect.”
3 Hilliste diagramNo crinoid paper is complete without camera lucida drawings (scale bar for all figures is one mm): (1) Hiiumaacrinus vinni n. gen. and n. sp.; (2) Radial circlet of an unrecognizable calceocrinid; (3) Basal circlet of an unrecognizable calceocrinid; (4) Protaxocrinus estoniensis n. sp.
4 Olev062511There are two new species and one new genus here. Hiiumaacrinus vinni is named first after the lovely Estonian island where the species is found, and then after our good friend and colleague Olev Vinn (above) at the University of Tartu. Olev first introduced me to the Ordovician and Silurian of Estonia, and then was an excellent field companion for Bill and me on our Estonian field trips.
2 Hiiumaa mapA reminder where Hiiumaa Island is, and for that matter, the nation of Estonia.

5 HillisteQuarry071312Here is Hilliste Quarry on Hiiumaa Island. Still one of my favorite places to work. Very, very quiet.

6 HillisteAusich071112Here is Bill Ausich in the quarry during our 2012 expedition. The pose is known among paleontologists as “the Walcott“.

7 Holdfasts071112Here is one of the specimens collected by Bill in July of 2012. You may recognize this field scene as figure 12 in the top image of this post. These are two examples of crinoid holdfasts on a tabulate coral.

Please welcome Hiiumaacrinus vinni and Protaxocrinus estoniensis to the paleontological world!

References:

Ausich, W.I. and Wilson, M.A. 2016. Llandovery (Early Silurian) crinoids from Hiiumaa Island, Estonia. Journal of Paleontology (early view).

Ausich, W.I., Wilson, M.A. and Vinn, O. 2012. Crinoids from the Silurian of Western Estonia (Phylum Echinodermata). Acta Palaeontologica Polonica 57: 613‒631.

Ausich, W.I., Wilson, M.A. and Vinn, O. 2015. Wenlock and Pridoli (Silurian) crinoids from Saaremaa, western Estonia (Phylum Echinodermata). Journal of Paleontology 89: 72‒81.

Wooster’s Fossils of the Week: Tiny athyridide brachiopods from the Lower Carboniferous of the West Midlands of England

September 9th, 2016

1 Hustedia radialis 585These little brachiopods were also in the recent gift package from Clive Champion, our English brachiopod expert and friend. They tested my photographic skills, being too large for our photomicroscope and at the limit of resolution for my camera with its extension tubes. They are the athyridide Hustedia radialis (Phillips, 1836) from the Chadian-Arundian Limestone (Viséan, Lower Carboniferous) exposed near Wetton, Staffordshire, England. Brachiopods of this size are often referred to as “micromorph“, with some debate as to whether they are dwarfed adults or juveniles. With this fauna the consensus is the former.

Athyridide brachiopods are “spire-bearing”, meaning they have complexly-spiraled lophophore supports (brachidia) inside their shells. The lophophore is a tentacular device that creates a water current and traps organic bits from it for nutrition. These tiny critters thus had surprisingly elaborate feeding systems. The first paleontologist to grind through these minuscule shells to sort out the twists and turns of their microscopic brachidia is a hero of science.
2 John Phillips (1800-1874)Hustedia radialis was named in 1836 by one of the most important English geologists of the 19th Century, John Phillips (1800-1874). He originally called it Terebratula radialis, a common genus name applied at the time to biconvex brachiopods with pedicle openings (the hole for the attaching stalk visible at the pointy end of the shell).
3 Geology of YorkshireHe named it in the second volume of his Geology of Yorkshire series.
4 Brachs PhillipsSee if you can find the two figures of Terebratula radialis in Plate XII of the book. (Hint: small, triangular and ribbed!)

John Phillips was born in Wiltshire in 1800. His mother was a sister of the famous William “Strata” Smith, another founding father of modern geology. Phillips father and mother died when he was only seven years old, so William Smith took over raising him, despite his genteel poverty. Phillips traveled with Smith throughout England in the course of making Smith’s famous 1815 map. Phillips had a spotty formal education, but was clearly a quick study. By 1824 he was organizing museum fossil collections in Yorkshire, and in 1826 he became keeper of the Yorkshire natural history museum. Phillips then advanced very quickly, helping organize the new British Association for the Advancement of Science, becoming a professor of geology at King’s College London, and then at the age of 34 he was elected a Fellow of the Royal Society. All the while he kept up a prodigious rate of publication. The honors and positions continued for Phillips, with him eventually becoming a Reader of Geology at Oxford University. A remarkable career with such an unpromising start.
5 Phillips 1841 160Phillips published the first geological time scale in 1841, inventing the term “Mesozoic” in the process. The above clip is from Phillips (1841, p. 160).
6 Phillips 1860 time scaleHere is his 1860 version of the geological time scale (Phillips, 1860, p. 51).

After an April 1874 dinner at All Souls College in Oxford, John Phillips fell down a flight of stone steps, dying the next day. No doubt but for this fall he would have continued producing geological work into the next decade.

References:

Brunton, C.H.C. 1984. Silicified brachiopods from the Viséan of County Fermanagh, Ireland (III). Rhynchonellids, spiriferids and terebratulids. Bulletin of the British Museum (Natural History), Geology 38: 27–130.

Brunton, C.H.C. and Champion, C. 1974. A Lower Carboniferous brachiopod fauna from the Manifold Valley, Staffordshire. Palaeontology 17: 811–840.

Mottequin, B., Sevastopulo, G. and Simon, E. 2015. Micromorph brachiopods from the late Asbian (Mississippian, Viséan) from northwest Ireland (Gleniff, County Sligo). Bulletin of Geosciences 90: 307-330.

Phillips, J. 1836. Illustrations of the geology of Yorkshire, Part 2. The mountain limestone district. 253 pp. John Murray, London.

Phillips, J. 1841. Figures and Descriptions of the Palaeozoic Fossils of Cornwall, Devon and West Somerset. 231 pp. Longman, Brown, Green and Longmans, London.

Phillips, J. 1860. Life on the earth: its origin and succession. 224 pp. Macmillan and Company, London.

7 Gould bookplateFun feature of that last reference: Google Books scanned a personal copy of Stephen Jay Gould, a famous American paleontologist and evolutionary theorist.

8 Darwin quoteOn one of the front pages is this penciled note: ‘Unreadable, dull’ – Charles Darwin to [unknown] 15/1/61. [UPDATE: See comment from Katherine Marenco below.]

Wooster’s Fossils of the Week: Mystery fossil solution — an oyster from the Middle Jurassic of southern England

August 30th, 2016

Mystery fossils 081916 585Last week I gave my students in Wooster’s Invertebrate Paleontology course a fossil to identify (shown above), using any techniques they want. This was their first task in the course, so it was difficult for most of them. I hope it was a good introduction to practical paleontology and the mysteries of taxonomy. One student, Josh Charlton, nailed it all the way to the species. Several other students got close.

These are Middle Jurassic oysters properly identified as Praeexogyra hebridica (Forbes, 1851). I collected them many years ago from the Frome Clay (Bathonian) at Langton Herring along the coast of Dorset, southern England. They are extremely common fossils there, crunching underfoot as they erode out into the surf. These oysters lived in estuaries, where there was a mix of fresh and marine waters. In 1976, John Hudson and our friend Tim Palmer sorted out the systematics and  evolution of this oyster species, moving it from Ostrea and Liostrea to the genus Praeexogyra.
Forbes diagramThis oyster species was originally described in 1851 as Ostrea hebridica by Edward Forbes (1815-1854) from Jurassic sediments on the Scottish Isle of Skye in the Inner Hebrides (hence the name). As was typical of many nineteenth century fossil descriptions, the illustrations (above) and diagnoses are not particularly helpful. Forbes (1851) wrote, “Being very familiar with the oysters of the Wealden and Purbeck I cannot admit this identification, nor can I refer the Loch Staffin shell to any known fossil, although, as usual in this variable genus, it is difficult to express in words its marked distinctions.” We wouldn’t get away with such a conclusion for a new species today, but to be fair, oysters are notoriously difficult to describe. Forbes knew that this species “inhabited brackish water” in the Jurassic.

Forbes bust to useEdward Forbes FRS, FGS (above) was born on the Isle of Man in 1815, the year of Waterloo. He was, as they said then, a sickly child unable to attend a regular school for long. He traveled to London when he was 16, though, to study art. That didn’t work out, so he became a medical student at the University of Edinburgh. Forbes was intrigued more with natural history than medicine (a common story!), so he dropped his medical plans and set out to become a naturalist skilled in paleontology, mineralogy, zoology, anatomy and botany. His younger brother David became a well-known mineralogist. Edward Forbes caught on quickly. In 1838 he published a summary of the mollusks found on the Isle of Man. He was 23 years old. Forbes traveled widely, accumulating more observations, experiences and colleagues. He had many publications and advocated numerous hypotheses about the distribution of life forms. Some had lasting value (like the distribution of flora before and after glaciation intervals) and others were a bit naive (such as his idea that there is no marine life below 300 fathoms). He was a president of the Geological Society of London (1853), and in 1854 became the Professor of Natural History at Edinburgh, his driving ambition. Unfortunately his health problems caught up with him and he died that year at age 39.

Edward Forbes played a critical role in the history of science by being a mentor of Thomas Henry Huxley. Forbes advised Huxley as a young man and helped him publish his earliest works. Forbes introduced Huxley to his circle of colleagues, which eventually led to the latter’s election to the Royal Society while only 26 years old. Huxley wrote a touching obituary for his young friend Edward Forbes.

References:

Anderson, F.W. and Cox, L.R. 1948. The “Loch Staffin Beds” of Skye; with notes on the molluscan fauna of the Great Estuarine Series. Proceedings of the Royal Physical Society of Edinburgh 23: 103-122.

Anderson, T.R. and Rice, T. 2006. Deserts on the sea floor: Edward Forbes and his azoic hypothesis for a lifeless deep ocean. Endeavour 30: 131-137.

Forbes, E. 1851. On the Estuary Beds and the Oxford Clay at Loch Staffin, in Skye. Quarterly Journal of the Geological Society 7(1-2): 104-113; plate 5, figs. 4a-4c.

Hudson, J.D. and Palmer, T.J. 1976. A euryhaline oyster from the Middle Jurassic and the origin of the true oysters. Palaeontology 19: 79-93.

Wooster’s Fossils of the Week: A puzzle for my paleo students!

August 26th, 2016

Mystery fossils 081916 585Every year I start my Invertebrate Paleontology course by giving every student an “unknown” fossil to identify. (Here is last year’s version.) This is not always easy since each student gets the same species from the same horizon and with the same preservation. As classes get larger (I have 27 students this semester) I have to dig deeper into my collections. I found some good ones today that have enough variation to challenge them.

These students are just beginning the journey, of course, so they usually know little about fossils. This exercise gets them into the online fossil literature immediately, and provokes early questions about the information used in taxonomy and the dilemmas of systematics based on morphology alone. Their task:

  1. Identify the fossil by scientific name as narrowly as possible. Phylum is a start, then Class, Order and so on down to the grand prize of correctly determining the species.
  2. Estimate the age of the fossil. Finding the period during which it lived is good; the actual stage it was found in, better.
  3. Make an educated guess at where this fossil was found. Chances are if you are right about the name and age, and then consider the places my students and I do fieldwork, you’ll come up with at least a region.

Next week I will post here the identity and collecting location of these fossils, along with the name of the student who came the closest to the right answers. You, Dear Reader, can make a guess in the comments!

Wooster’s Fossils of the Week: Another molluscan assemblage from the Miocene of Maryland (side two)

August 19th, 2016

1 Calvert 2 585Last month we featured a fossil slab kindly donated by Dale Chadwick of Lancaster, Pennsylvania. Dale is an enthusiastic fossil collector with a very useful website for his favorite sites and specimens. I promised to show the other side of this rock, and here it is.

Again, this is a fine sandstone from the famous Calvert Formation (lower to middle Miocene) exposed at the Calvert Cliffs, Plum Point, Calvert County, Maryland, in the stratigraphic Shattuck Zone 10. Some horizons are especially fossiliferous with large numbers of gastropods and bivalves. This is what we refer to us a death assemblage, meaning these shells are not preserved in their life positions but how they accumulated just before final burial. These rocks and their fossils were the initial basis of Susan Kidwell’s important work on taphonomic feedback, or how shell accumulations affect the succeeding living communities.

So what are the prominent fossils in this slab? Dale has the answers on his website. I’ve annotated the image and made a list below:

2 Calvert 2 585 labelsA Astarte sp. (a veneroid bivalve)
B Glycymeris parlis (an arcoid bivalve)
C Siphonalia devexa (a buccinid gastropod)
D Turritella variablis (a turritellid gastropod)

Thank you again to Dale Chadwick for this gift! I will use it in my paleontology course this very month.

References:

Kelley, P.H., 1983, Evolutionary patterns of eight Chesapeake Group molluscs: Evidence for the model of punctuated equilibria: Journal of Paleontology 57: 581–598.

Kelley, P.H. 1988. Predation by Miocene gastropods of the Chesapeake Group: stereotyped and predictable. Palaios 3: 436-448.

Kidwell, S.M. 1986. Taphonomic feedback in Miocene assemblages: Testing the role of dead hardparts in benthic communities: Palaios 1: 239–255.

Kidwell, S.M., Powars, D.S., Edwards, L.E. and Vogt, P.R. 2015. Miocene stratigraphy and paleoenvironments of the Calvert Cliffs, Maryland, in Brezinski, D.K., Halka, J.P. and Ortt, R.A., Jr., eds., Tripping from the Fall Line: Field Excursions for the GSA Annual Meeting, Baltimore, 2015: Geological Society of America Field Guide 40, p. 231–279.

Wooster’s Fossils of the Week: Trepostome bryozoans, burrow systems, and bedding features in an Upper Ordovician limestone from southeastern Minnesota

August 12th, 2016

1 DSC_1322One of the little mysteries on the recent Minnesota research trip by Wooster students, faculty and staff is the origin of thin limestone beds in the middle of the thick shales of the Decorah Formation (Upper Ordovician). How did such accumulations of almost pure carbonate develop on such a muddy seafloor? Are they storm beds? Some sort of diagenetic feature? The records of brief sealevel changes? Brief interruptions in the supply of silicate sediments to the basin? Turbidites of carbonate material swept into a deeper basin? Above is a view of the top surface of such a limestone bed, this one found in the middle of the Decorah in Shop Quarry (N 43.97232°, W 92.38332°). The light-colored twiggy objects are broken colonies of trepostome bryozoans; the network of holes are burrows of a trace fossil called Chondrites.

3 Wangs carbonate bedAn outcrop view of one of these carbonate beds in the Decorah Formation, this one at Wangs Corner (N 44.41047°, W 92.98338°). These units are only a few centimeters thick, and have a variety of petrographic fabrics. This one appears to be an almost pure biosparite with Thalassinoides burrows penetrating from above carrying down a light brown sediment.

2 DSC_1325Back to our slab from the Decorah at Shop Quarry with a closer view of the trepostome bryozoans and round holes representing the trace fossil Chondrites.

3 DSC_1333Sawing a rock and then polishing a cut surface is always fun and profitable! This is a cross-section through the Shop Quarry slab, oriented with the top upwards. A little bit of iron oxide diffused through the sediments provides the touches of red in the fabric of the limestone.

4 DSC_1341This closer view of the cut surface shows the exquisite bedding features, along with the bryozoans (B) and trace fossils (T) in cross-section. The burrows pass through the bedding and pie down into the rock a brownish sediment from above. These burrows were made by some sort of deposit-feeding organism that was mining the sediment for organic material. The bedded sediment may be slightly graded in grain size, meaning the many beds may consist of thin fining-upwards sequences. Note how the beds are contorted around the bryozoans as if they were dropped into the sediment while it was still accumulating.

This slab of bryozoans, trace fossils and contorted laminae looks to me like a storm bed formed quickly during and after the seafloor was significantly disturbed by currents. When conditions returned to normal some worm-like deposit-feeders in the fine sediment above sent their mining tunnels down deep into the carbonate looking for food. We have a hypothesis to test!

Wooster’s Fossil of the Week: A mytilid bivalve from the Middle Jurassic of southern Israel

August 5th, 2016

1 Mytilus (Falcimytilus) jurensis 585This week’s specimen comes from one of my favorite fossiliferous units: the Matmor Formation (Middle Jurassic, Callovian) of Makhtesh Gadol in southern Israel. I’ve been delighted by the fossils and lithologies of the Matmor since 2003. This particular fossil is exposed in a bedding plane of the very rich subunit 65, which I’ve mentioned before in this blog. It is a mytilid bivalve identified as Mytilus (Falcimytilus) jurensis It has the classic wing shape of its order.
2 Mytilus (Falcimytilus) jurensisM. jurensis is very common in the Matmor Formation, especially in the upper third where it can be seen protruding from limestones at a variety of angles. The species was widespread throughout the Tethys Ocean, now recorded by sediments in the Middle East and Mediterranean regions.
3 mytilids090809Mytilid bivalves are very common today as well, and they have the same life mode as they did at least 150 million years ago. They attach to hard substrates in shallow waters with strong fibers they secrete called byssal threads. Above we see our M. jurensis shell with several others clustered around a gastropod shell to which they were attached. The organic byssal threads are long gone, of course, but the shells remain in their living positions.

I like to use these Fossils of the Week to explore their taxonomic histories. The specimens, after all, are usually not exceptionally well preserved or rare, but they all have stories. Mytilus (Falcimytilus) jurensis proved to be a challenge when it came to identifying the author of the species.
4 MNHN figFirst I went to the online catalogue of the Muséum National D’Histoire Naturelle in Paris — an excellent resource. There I found the above image and information. Someone named Roemer named the species in 1836. So who was this Roemer and what was the publication?
5 Friedrich Adolph RoemerAfter considerable searching, I learned our taxonomist was Friedrich Adolph Roemer (1809-1869), a German geologist born in Hildesheim, part of the Kingdom of Westphalia. He had a younger brother, Carl Ferdinand von Roemer, who was also a geologist, creating some confusion.
6 Oolithen-GebrigesFriedrich Roemer has an 1836 book (above) that roughly translates as The Fossils of the North German Oolitic Mountains, “oolitic” referring to a kind of limestone common in the European Jurassic; for awhile it was essentially synonymous with “Jurassic”.
7 Plate IV, fig 10On Plate IV, fig. 10, of this 1836 book is a pair of drawings of Mytilus jurensis. So far all is on track for sorting out the taxonomic history of the species.
8 p 89Surprise! When we look at the description in the text on page 89, we see that Roemer gives an undated credit for the species to “Merain”. Who is Merain?
9 Thurmann p 13I thought I’d never find the identity of this “Merain”, but through the extraordinary resource of Google Books, I uncovered the earliest record of Mytilus jurensis. It is on page 13 of Thurmann (1833). Note that following the species (fourth line above) is “Mèr.” and then “n. sp.”, meaning “new species”. (I have no idea what the intervening “M. Bas.” indicates. [Update: See comment by Christopher Taylor below.]) There is no description of the species, and no illustration, but there’s the first mention of it.

So is “Mèr.” short for Roemer’s “Merain”? Turns out Roemer misspelled the last three letters — it is “Merian”.
10 Peter_MerianPeter Merian (1795-1883) was a Swiss geologist and paleontologist who was born in Basel. He studied scientific topics at the University of Basel, the Academy of Geneva, and the University of Gottingen. After two years in Paris, Merian returned to Baasel and began to specialize in the geology and fossils of the Jura Mountains. He was appointed a professor of physics and chemistry at the University of Basel, and later an honorary professor of geology and paleontology. He was also Director of the Natural History Museum in Basel. Along with his work on Triassic and Jurassic fossils, he also made contributions to glaciology and meteorology. Peter Merian died in Basel in 1883 after a long, notable career. He certainly looked the part of a dashing 19th Century Swiss geologist. Kevin McNally could play him in the movie! And now we know that he was the man who named Mytilus jurensis in 1833. Roemer (1836) was probably credited with the species at one point because he had the first description and figures. Merian, apparently, just provided the name in someone else’s book.
11 Merian map JuraHere is an 1829 geological map by Peter Merian of a portion of the Jura Mountains, one of the first of the region.

References:

Cox, L.R. 1937. Notes on Jurassic Lamelibranchia V. On a new subgenus of Mytilus and a new Mytilus-like genus. Journal of Molluscan Studies 22: 339-348.

Freneix, S. 1965 – Les Bivalves du Jurassique moyen et supérieur du Sahara tunisien (Arcacea, Pteriacea, Pectinacea, Ostreacea, Mytilacea). Annales de Paléontologie, t. 51, vol. 1, p. 51-113.

Liu, C. 1995. Jurassic bivalve palaeobiogeography of the Proto-Atlantic and application of multivariate analysis method to palaeobiogeography. Beringeria 16: 31123.

Liu, C., Heinze, M. and Fürsich, F.T. 1998. Bivalve provinces in the Proto-Atlantic and along the southern margin of the Tethys in the Jurassic. Palaeogeography, Palaeoclimatology, Palaeoecology 137: 127-151.

Merian, P. 1829. Geognostischer Durchschnitt durch das Jura-Gebirge von Basel bis Kestenholz bey Aarwangen, mit Bemerkungen über den Schichtenbau des Jura im Allgemeinen. Zürich.

Roemer, F.A. 1836. Die Versteinerungen des Nordeutschen Oolithen-Gebirges. Hahn. 218 pages.

Thurmann, J. 1833. Essai sur les soulèvemens Jurassiques du Porrentruy, avec une description géognostique des terrains secondaires de ce pays, et des considérations générales sur les chaines du Jura. Mém. Soc. Hist. Nat. Strasbourg 1: l-84.

Wooster’s Fossil of the Week: A new Late Ordovician bryozoan from Oklahoma

July 29th, 2016

1 Color brach Zigzagopora encrustedI am very pleased to introduce a new bryozoan genus and species recently described in the First View section of the Journal of Paleontology. Paul Taylor (Natural History Museum, London) and I present: “A new runner-like cyclostome bryozoan from the Bromide Formation (Sandbian, Upper Ordovician) of Oklahoma and its phylogenetic affinities”. The bryozoan is shown above encrusting the interior of an orthid brachiopod identified as Multicostella sulcata (thanks, Alycia Stigall!) in the Lower Echinoderm Zone of the Mountain Lake Member of the Bromide Formation near Fittstown, Oklahoma. We are particularly proud of its new scientific name. Here’s the abstract:

Zigzagopora wigleyensis n. gen. n. sp. is an Upper Ordovician (Sandbian, early Caradoc) cyclostome bryozoan from the Arbuckle Mountains of Oklahoma, USA. It has runner-type colonies characterized by a mostly uniserial, geniculate arrangement of monomorphic zooids that bud alternately left and right, producing a zig-zag pattern of growth. This new genus has calcified interior walls and non-pseudoporous exterior walls. It is thus most likely affiliated with the paleotubuliporine Family Sagenellidae, despite superficial similarities with the corynotrypid cyclostomes with which it co-occurs.”

You’ve got to love a job where you can coin a name like Zigzagopora wigleyensis. The fortuitous species name, by the way, refers to the Wigley Quarry in Oklahoma (below).

Slide08_052815Here is a pictorial guide to Zigzagopora wigleyensis, featuring Paul’s excellent Scanning Electron Microscope images:
2 Good zigs 0p20This is what we mean by a “uniserial, geniculate arrangement of monomorphic zooids that bud alternately left and right”. The zooids are the little skeletal tubes, each of which housed an individual bryozoan connected by soft tissue to the rest of the colony. Uniserial means that most series of zooids have just one branching from another. Geniculate means “bent abruptly” like a knee joint. Monomorphic refers to the shape of each zooid being about the same. The scale bar is 0.20 mm.

3 Zig zooid shape 0p10

It is this zig-zag shape that makes Zigzagopora distinctive. Scale bar is 0.10 mm.

4 Zig over Cory 0p20The abstract ends with “… superficial similarities with the corynotrypid cyclostomes with which it co-occurs.” In this scene Zigzagopora (Z) has overgrown a branch of the encrusting cyclostome bryozoan Corynotrypa (C). These bryozoans are obviously similar, but the geniculate (our new word!) nature of Zigzagopora sets it apart. This is significant beyond just the shape of the colony: it indicates a different kind of budding of one zooid from another. The scale bar is 0.20 mm.

5 Ancestrula Zig 0p06All bryozoans start from an initial zooid called the ancestrula. It is not always easy to find, but is critical for identification and systematics. The arrow points to the protoecium, the first chamber. The scale bar is 0.06 mm.

6 Pore in zooecium 0p03Inside a broken zooid we can see an interior wall surface and a tiny pore. Really tiny. This is likely an interzooidal pore connecting the soft parts of the zooids. Scale bar is 0.03 mm.

7 Extended zig 0p60Here, then, is Zigzagopora wigleyensis, new to science. It is a tiny new piece for the puzzle that is the evolution of cyclostome bryozoans. It is one of countless billions of species in the history of life, but unique nonetheless.

References:

Taylor, P.D. and Wilson, M.A. 1994. Corynotrypa from the Ordovician of North America: colony form in a primitive stenolaemate bryozoan: Journal of Paleontology 68: 241–257.

Wilson, M.A. and Taylor, P.D. 2016. A new runner-like cyclostome bryozoan from the Bromide Formation (Sandbian, Upper Ordovician) of Oklahoma and its phylogenetic affinities. Journal of Paleontology 90: 413-417.

UPDATE: Zigzagopora wigleyensis made the cover!

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Wooster’s Fossil of the Week: A bored rhynchonellid brachiopod from the Middle Jurassic of France

July 22nd, 2016

1 Kutchi dorsal 585Another beautiful brachiopod this week from our friend Mr. Clive Champion in England. His donations to our collections have considerably enriched our teaching program, especially for brachiopods! This specimen is the rhynchonellid Kutchirhynchia morieri (Davidson, 1852) from the Middle Jurassic (Upper Bathonian) of Luc-sur-Mer, France. This is a view of the dorsal side with the dorsal valve on top with the ventral valve (containing the round opening from which the stalk-like pedicle extended) seen below it. Like most rhynchonellids, the valves have distinct plicae (thick ridges) where the shell is tightly folded.
2 Kutchi ventral 585This is the ventral view showing only the exterior of the ventral valve. Note the curved serpulid worm tube attached near the center, and the squiggly borings. These were likely sclerobionts (hard substrate dwellers) that occupied the brachiopod shell when the animal was still alive, since the dorsal and ventral valves are still articulated. The borings are probably of the ichnogenus Talpina, but I would have to grind down the shell to know for certain.
SSBuckmanThe genus Kutchirhynchia was named by Sydney Savory Buckman (1860-1929) in 1917. We met Buckman earlier in this blog when looking at another of his Jurassic rhynchonellid genera, Burmirhynchia. We learned a lot more about Buckman this summer during our expedition to the Jurassic of Dorset, where he did much of his work. He is best known there as an ammonite worker and stratigrapher (and massive taxonomic splitter).
3 Thomas DavidsonThe species Kutchirhynchia morieri was named by the Scottish paleontologist Thomas Davidson (1817-1885), who originally placed it in the large genus Rhynchonella. Buckman acknowledges Davidson in an ammonite monographs as one of his “earliest geological friends”. (Davidson was 43 years older than Buckman.) Davidson was born in Edinburgh to wealthy parents. He studied at the University of Edinburgh and then in France, Italy and Switzerland, where he made many long geological tours. He was convinced by the German paleontologist Christian Leopold von Buch (1774-1853) to work on fossil brachiopods. (Von Buch was 43 years older than Davidson. Nice to see the older generation having an effect on those kids!) Davidson stayed with brachiopods his entire career, producing massive monographs on both fossil and recent forms. He engraved his own plates on stone, and there are more than 200 of them. Davidson was elected a fellow of the Geological Society of London in 1852, awarded the Wollaston medal in 1865. In 1857 he was elected a Fellow of the Royal Society, receiving their Royal medal in 1870. Upon his death in Brighton, England, in 1885, his entire collection of fossil and recent brachiopods went to the British Museum.
4 Elizabeth GrayThis is a good place to mention Elizabeth Anderson Gray (1831-1924), an important fossil collector in Scotland who supplied Thomas Davidson and many other paleontologists with critical specimens for their work. She is one of the many unnoticed heroes of paleontology, being rarely acknowledged publicly and then overshadowed by her husband. She worked primarily in the Ordovician and Silurian and so did not give Davidson Jurassic rhynchonellids, but she provided hundreds of brachiopods from the early Paleozoic. I love this image of her knocking out fossils with a hammer, just like we do today. Trowelblazers has an excellent biographical page on Elizabeth Anderson Gray.

References:

Buckman, S.S. 1917. The Brachiopoda of the Namyau Beds, Northern Shan States, Burma. Palaeontologia lndica 3(2): 1-254.

Gilman, D.C., Thurston, H.T. and Colby, F.M., eds. 1905. Davidson, Thomas (paleontologist). New International Encyclopedia (1st ed.). New York: Dodd, Mead.

Shi, X. and Grant, R.E. 1993. Jurassic rhynchonellids: internal structures and taxonomic revisions. Smithsonian Contributions to Paleobiology, Number 73, 190 pages.

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