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List of Oral Presentations

 

Interpreting the life styles of trilobites

Presenter: Richard Fortey

Presentation to be held in English!

I am often asked by students: why are there so many species of trilobites? During more than forty years studying trilobites I have come up with a few answers. In my talk I review some of the research that I have carried out during my career at the Natural History Museum, in London. The interpretation of pelagic life habits is now perhaps generally accepted, and I began to think about this when I published my first systematic paper on Opipeuterella.

I went on to consider the different biotopes in which such trilobites might have lived, and experimented on the comparatively good streamlining of some of the larger species. Depth zonation added to the picture of trilobites occupying much of the water column. Other workers did much to elucidate trilobite vision, but I had the chance to describe the unique eye of Erbenochile. As for benthic trilobites, the realisation that ventral structures -especially the hypostome - might be of importance in interpreting feeding habits, led to  my distinguishing  predator/scavenger trilobites from  sediment grazers, and the highly specialised filter feeders.  

More speculatively, some  trilobites derived from particle feeders and occupying anoxic environments were considered as possibly living symbiotically with sulphur loving bacteria. The recognition of different depth-controlled biofacies in which these different life habits could play out accounts further for some of the species richness of the group. Finally palaeogeography can be added to the scenario, as driver of evolution at the regional level.

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Trilobites of the Russian Ordovician around Saint Petersburg – Completely without a Fake !?

Presenter: Paul Freitag

Ordovician trilobites from the region around Saint Petersburg are world-renowned and represented in many collections. Unfortunately the market sometimes surprises with strongly changed or composed trilobites – partly a fake, partly documented restoration. Is it caused by the preservation of the trilobites or should a very perfect piece be created to achieve the best possible price?  On the basis of observations in own preparations this question will be followed. The preparation process and possible restorations will be made transparent.

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Black Cat Mountain, an inside view of the quarry

Presenter: Andries Weug

Since several decades „Black Cat Mountain“ is the acme for a rich trilobite fauna from the Haragan and Bois d' Arc formation among trilobite collectors. Although every collector knows these early Devonian trilobites, only few informations are available about where these fossils are coming from. This lecture will present the locality, its conditions as well as the person behind „Black Cat Mountain“.

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External and internal values: A Chotecops from Bundenbach

Presenter: Klaus Bartl

The Lower Devonian Hunsrueck slates from the region Bundenbach/Germany are known as a Konservatlagerstätte that bears horizons which deliver fossils with soft tissue preservation. Though no new material is available since the end of the roofslate quarrying in 1999, successful scientific research continues due to archive material from private and public collections, which is examinated by using latest technologies. The presentation gives a look at closed roofslate quarries in Bundenbach, and shows a trilobite Chotecops sp. (with evidence of soft tissue preservation of interior structures) as an example of the successful cooperation of a private fossil collector with scientists – the contact had been established at the 2nd German Conference on Trilobites in 2011.

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Pore canals in tubercles of calymenids

Presenter: Ulrich Münder

Trilobites of the family Calymenidae are present in many collections, also from the Silurian of the Baltic island Gotland. The calymenids have central pore canals in the tubercles on all exoskeleton elements. The presented examples of Calymene frontosa LINDSTRÖM 1885 and Calymene blumenbachii tuberculata SCHRANK 1970 shows central pores or with pyrite filled canals in the tubercles of the trilobite cuticle.

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The analysis of trilobite eyes and its relevance for the understanding of the evolution of vision

Presenter: Brigitte Schoenemann

The understanding of the evolution of vision is based on the comparison of visual systems with different complexity of recent organisms. These systems, however, belong to modern organisms, adapted to modern environmental constraints. The methodical problem lies in the fact, that over a long time it seem to be impossible to trace and document soft tissues such as sensory tissues or their accessory cells. Excellent preservations such as of Lagerstätten and modern techniques, such as x-ray tomography or the use of synchrotron radiation, however, revealed insights to how ancient visual systems were constructed, thus how they worked and how their performances were. Trilobites are an important part of this field of research, revealing evidence by whitnessing processes in the evolution of vision directly and first-hand.

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Four rare Trilobites from Glacial Erratics of the Middle Ordovician

Presenter: Heinrich Schöning

From glacial erratics of baltoscandic origin four rare trilobites are introduced: Phorocephala teilhardi Schöning & Popp 2016, up to now the oldest representative of this genus from the Ordovician of Europe. It was found in a glacial erratic of the so-called middle grey orthoceratid limestone (Kunda stage, lower Darriwilian).
Also from the Kunda stage come two different heliomerinid trilobites whose cranidia were found in erratics of the middle red orthoceratid limestone:
Heliomera? parvulobata Schöning 1994 and Heliomeroides n. sp.?. Cranidia of these different types partly appear together in the same glacial boulder. Compared to the already known Heliomera-/Heliomeroides species, these findings should also belong to the oldest representatives of the
Heliomerinae, Evitt 1951.
Finally, a cranidium of unknown systematic position becomes announced from a glacial boulder of the lower red orthoceratid limestone (high Dapingian –basal Darriwilian).

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Healed shell injuries of Flexicalymene retrorsa from the Ordovician of Ohio, USA

Presenter: Jens Koppka

Complete specimens of Flexicalymene retrorsa are quite common in the Mt. Orab „butter shale“-bed of the Arnheim Formation (Cincinnatian, Upper Ordovician) of Ohio and therefore well distributed in collections around the world. Probably it is less known that a striking number of specimens show
small dents and partially deep stab injuries as observed after a careful preparation of a couple of complete specimens, most of them enrolled ones.
In the lecture the site itself, palaeoecological features and particularly the trilobite injuries will be introduced and possible predators will be discussed.

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Some Findings of Homalonotid Trilobites from the Baltoscandian faunal province

Presenter: Stefan Liebermann

In contrast to the corresponding deposits in the area of Gondwana, findings of the family Homalonotidae are relatively rare in Baltoscandia.
Some findings from the outcrops of Sweden as well as from the glacial erratics of Northern Germany are introduced.
The partial good preservation enables to show details of the shell surface.

***

Abberant genal spines on Mississippian trilobites

Peter Müller (presenting) & Gerhard Hahn

The Cystispininae are a trilobite group, whose representatives are characterised by aberrant built genal spines. Cylindrical up to very bubble-like spine types can be distinguished. Geographically, the areas of life of these animals were located in the deep basin and ridge regions of the Rhenohercynic Ocean (Kulm facies) with its centre in Central Europe. Their stratigraphical spreading is known from the uppermost Tournaisian to the basal Upper Visean. Probably, these unusual structures are reactions to severely affected living conditions.

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Trilobites from the North: lower Cambrian olenelloids from the Digermulen Peninsula, Arctic Norway

Jan Ove R. Ebbestad (presenting), Anette Högström, Magne Høyberget, Wendy L. Taylor and Sören Jensen

Presentation to be held in English!

Scandinavian lower Cambrian stratigraphy is largely trilobite based, defined by the occurrence of distinct trilobite assemblages with classic olenelloid trilobites like Holmia and Kjerulfia. Except for a few localities in Scandinavia where these taxa are fairly common, most occurrences are represented by a single or a few incomplete specimens at the best. Since 2011 a collecting effort in the lower Cambrian strata on the Digermulen Peninsula, Arctic Norway has yielded close to 100 specimens of at least three different olenelloid trilobite taxa, including Kjerulfia lata, Kjerulfia sp. and Elliptocephalus sp., as well as an ellipsocephalid.

The specimens are found in a narrow stratigraphical interval in the silty mudstone of the Duolbagáisá Formation, and are accompanied by rich material of organic walled microfossils and trace fossils. The age constraints on the occurrence are therefore well established, placing the trilobites in the Holmia kjerulfi assemblage Zone. Compared to the classical Tømten locality in the Mjøsa area, southern Norway, the Digermulen Peninsula assemblage lacks Holmia kjerulfi. Ellipsocephalids are found with the new material and also slightly higher in the succession. Although the occurrence of trilobites in the Duolbagáisá Formation have been known for a long time, the new extensive trilobite material is both better preserved and more abundant, even compared to most other places in Scandinavia. This ensures that this succession will be a major reference for lower Cambrian trilobite zonation in this part of the world.

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Brantevik – an El Dorado for Agnostid Hunters

Presenter: Hans-Jürgen Schmütz

Lower Cambrian up to Upper Ordovician strata are exhibited at the coast between Brantevik and Gislövshammar (Skåne /Southern Sweden).
Sediments of Middle Cambrian age (Cambrian 3 series), like the Exsulans, Punctuosus and Andrarum limestone, are very interesting for agnostid hunters.

Several agnostids are presented with the aim to raise even more the interest to this small trilobites.

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Trilobites in glacial erratics of Baltic Sea limestone from south of Berlin

Presenter: Tobias Surawski

Normally fossils are very rare in glacial erratics of the upper Ordovician Baltic Sea limestone (Baltic limestone). Erratic boulders especially of the Nabala stage accumulated in a gravel pit south of Berlin are the exception.

During intense collecting in the last 15 years a high number of such Baltic Sea limestone boulders are found and a rich fossil fauna was retrieved. Trilobites are represented by a lot of different genera. Sometimes even the complete exoskeleton of the trilobite is preserved.The lecture will give an overview of the trilobites found in this Baltic Sea limestone erratics.

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Intraspecific variability in trilobite Acanthopyge (A.) haueri (Barrande, 1846) from the Middle Devonian (Eifelian) of the Barrandian area (Czech Republic)

Petr Budil (presenting), Jiří Frýda, Brian D. E. Chatterton, Joan Corbacho, Václav Vokáč

Presentation to be held in English!

As an introductory study to the revision of Acanthopyge (Acanthopyge) Hawle & Corda, 1847, a thorough biometric measurement of all applicable specimens of the genotype species Acanthopyge (A.) haueri (Barrande, 1846) from the Middle Devonian (Eifelian) of the Barrandian area (Czech Republic) has been done. These measurements involved an examination of 162 cephala, 136 pygidia, and 50 hypostomes (no entire and/or articulated specimen is known up to date). This material was gathered within almost 200 year’s investigation of eponymous shallow-water Acanthopyge Limestone, to which the species is confined.The relatively extensive but mostly museum material unfortunately lacks exact stratigraphical affiliation (e.g. position within the Acanthopyge Limestone) in most cases. It is a great difficulty because the gathered data show notable intraspecific variability within a supposedly well-defined species. ….

(First part only, the complete abstract will be published in the printed version.)

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Trilobites (Asteropyginae, Odontochilinae & Homalonotinae) from the Pragian of Aïn-Al-Aliliga (western Meseta, NW Morocco)

Presenter: Stephan Helling

Morocco is long known for its excellent and highly diverse trilobite faunas which are often mined, prepared and sold on the world market. Most of these specimens come from lower and middle Devonian strata of the Tafilalt and Maider regions, both are located in the northeastern part of the country. Therefore comparatively little is known about the Devonian trilobites of the Meseta Region in NW Morocco from the same time interval. The presented material comes from lower Devonian strata of Aïn Aliliga, an outcrop in the western Meseta, ca. 13 km NE from the town Bouznika.

The Pragian fauna from Aïn-Al-Aliliga comprises, beneath the trilobites, relatively common macroscopically visible ostracods as well as rare brachiopods and rugose corals. Disarticulated trilobites in shell preservation are the main faunal element. So far the following genera are known from this locality.

Wenndorfia Sandford, 2005. In comparison to other taxa found at Aïn-Al-Aliliga, specimens of Wenndorfia are quite rare. The most common morphological elements are isolated pleurae, while only one cephalon is known. Compared to other representatives of the genus, the specimens of Aïn-Al-Aliliga are considerably smaller.

Odontochile Hawle & Corda, 1847. Specimens belonging to this genus are also rare within the trilobite fauna of Aïn-Al-Aliliga. Most common are broken or complete pygidia, which allow a taxonomic classification, while cephala from this genus are not known so far.

Metacanthina Pillet, 1935. Taxa from this genus are the main component of the trilobite fauna at Aïn-Al-Aliliga. Isolated cephala and pygidia are quite common in the Pragian strata. In total there are three different taxa, wherein at least two of these taxa represent new species.

The above mentioned taxa show a clear faunal link to time synchronous strata of the Maider and Dra-Valley, situated in south Morocco, while faunal links to the Tafilalt are not so obvious.

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Preparation of Trilobites from glacial erratics of Ludibundus Limestone

Presenter: Paul Freitag

Complete trilobites from erratic boulders are quite rare, but are most commonly found in the Ludibundus Limestone. These sought after erratic boulders are rather hard, and the trilobites are only discernible by cross sections. The way these trilobite findings turn to showcase pieces, and what needs to be cosidered during preparation, will be illustrated by means of own preparations.

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Ordovician proetid trilobites from Baltoscandia - a perspective

Presenter: Adrian Popp

Trilobites are one of the most successful animal groups in Earth history, providing several index fossils. Among the trilobites the order Proetida (sensu Fortey & Owens 1975) is, depending on systematic definition, the longest ranging one.

Studying the Ordovician Proetida from Baltoscandia is an unusual, but a fascinating and rewarding field (Popp 2011). Following up the paper by Pärnaste, Popp & Owens (2009) a current perspective shall be given, emphasising the important role of geschiebes and new findings from them for Baltoscandia. Many new species are only known from geschiebes, which also applies for the proetids: Stenoblepharum glaciviator Popp & Schöning 2006 and Phorocephala teilhardi Schöning & Popp 2015 are just two examples.

The Ordovician sediments of the Lake Siljan area (Dalarne, Sweden), of which the Boda limestone (late Katian to early Hirnantian) is the most popular, deliver a broad range of proetids. Further Baltoscandian sites, for example from Estonia, will be briefly presented. The late Ordovician erratic boulders from the so called WWW area (in the German – Dutch border region: Wielen-Wilsum-Westerhaar) contain interesting minute trilobites.

Besides the Ordovician Palaeogeography of Baltoscandia, the splitting of the order Proetida (sensu Fortey & Owens 1975) recently proposed by Adrain (2011) into the orders Proetida and Aulacopleurida will be explained.

Literature:

Adrain, J. M. (2011): Class Trilobita Walch, 1771. In: Zhang, Z.-Q. (Ed.) Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness. Zootaxa 3148: 104 - 109, Magnolia Press.

Fortey, R.A. & Owens, R.M. (1975): Proetida – a new order of trilobites. In: Martinsson, A. (Ed.) Evolution and morphology of the Trilobita, Trilobitoidea and Merostomata. Fossils and Strata 4, 227–239, Universitetsforlaget.

Pärnaste, H., Popp, A. & Owens, R.M. (2009): Distribution of the order Proetida (Trilobita) in Baltoscandian Ordovician strata. Estonian Journal of Earth Sciences 58(1), 10-23.

Popp, A. (2011): Ordovician Proetid Trilobites in Baltoscandia and Germany. Thesis on Natural and Exact Sciences B105, 1-43 (+ 67), TUT Press.

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Crystalline cones in trilobite compound eyes?

Presenter: Gerhard Scholtz

Compound eyes play a central role for the understanding of arthropod evolution and ecology. In Recent arthropods two major types of compound eyes can be discriminated. Those that possess ommatidia with a dioptric apparatus comprising a cuticular lens and a cellular crystalline cone and those that have a cuticular lens that shows a cone-like extension fulfilling the same purpose of light collecting and guiding to the retinula cells. The latter type is characteristic for horseshoe crabs among Chelicerates and thus often interpreted as being an ancestral character for arthropods. In contrast, the existence of a crystalline cone made up by specialized cone cells occurs in myriapods, crustaceans, and hexapods and is interpreted as apomorphy of Mandibulata. The phylogenetic position of trilobites within the arthropods is still elusive. There are indications for a close relationship to chelicerates and likewise for a mandibulate affinity. Trilobites show two different eye types called schizochroal and holochroal that differ in structure, size, arrangement, and number. It is quite clear from the internal trilobite phylogeny that the holochroal eyes are plesiomorphic among Trilobita. Yet, the questions arises whether the holochroal eyes of trilobites correspond rather to chelicerate or mandibulate compound eyes. So far, the existence of crystalline cones has not been shown for trilobites. Cuticular cones could have been lost during moult or through diagenetic processes. To address this question, we investigated trilobite eyes using modern light-microscopy and CT (Bessy II) and compared the exuviae of Recent arthropods. Direct and indirect evidence that trilobite eyes possess a crystalline cone and the evolutionary consequences are discussed.

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Angelin‘s „Palaeontologia Scandinavica"

Presenter: Frank Rudolph

Nils Peter Angelin was born in 1805 as son of a blacksmith in Lund. At 16, he began his studies in his home town. His interest lay especially in the sciences, above all geology and paleontology. Angelin went on a lot of travels through Norway and Sweden, during which he intensely collected paleozoic fossils. He made a living as a teacher and by selling fossils to museums and private citizens. Temporarily, he also traded in antiquarian books. Thanks to some financial support, Angelin was able to visit his famous colleague Joachim Barrande in Prague. At first, Angelin published his research results about trilobites in his „Palaeontologia Svecica“ in 1851 and in 1854 in an expanded form with the title „Palaeontologia Scandinavica“. Both works were self-published. During the 35 years being at the university, Angelin didn’t take a single exam. In 1857 he was at last awarded an Honorary doctorate by the University of Breslau. Following that, Angelin became an assistant at the university of Lund in 1860 and professor in Stockholm in 1864. In 1861, he published a very exact geological map of Skåne. Angelin died in 1876 in Stockholm. Two years after his death, a revised edition of his
„Palaeontologia Scandinavica“ that he had been working on until his final days was published. While the first edition of 1851 has 24 plates, the edition of 1854 already had 42 plates and the one of 1878 had 44 plates overall plus Plate A and B with a depiction of ostracods and other arthropods. There are 11 additional plates, partially in large format that are mostly unknown and remain unpublished to this day. They were planned as a supplement to his life’s work, the „Palaeontologia Scandinavica“. Regnell tells of them in 1951 in GFF but doesn’t add illustrations. These plates will be shown here the very first time, although they lack the explanatory descriptions.

The „Iconographia Crinoideorum“ (1878) and the „Fragmenta Silurica“ (1880) are two more large format plates of Angelin, that were also published posthumously by Gustaf Lindström and Sven Loven.

The expansive collections of Angelin are kept now in the Museum of Natural History in Stockholm.

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The Preparation of Trilobites from Glacial Erratics: a Resume

Presenter:Hans-Hartmut Krueger

Trilobites from Middle and Upper Ordovician glacial erratics are presented. They derived from Orthoceratid limestone boulders and from erratics of the
Baltic Sea limestone which are hard to prepare. Cross fractures through trilobites as they are found, and the resultant specimen after the
preparation process will be shown. Some possibilities to find trilobites are also discussed.

***

Tretaspis seticornis from glacial erratics of Baltic Sea limestone from
Ziezow

Presenter: Holger Hanff

In the gravel pit Ziezow in Brandenburg several thousand erratics of the upper Ordovician Baltic Sea limestone were collected in the time from 2008 to 2015. These white-grey, relatively soft limestone boulders are of Nabala-and Vormsi age.  
Trilobite remains are preserved undeformed except in marly layers inside the boulders. Fossils are normally rare in this type of erratics. The very high number of boulders made it possible to find a lot of fossils, for instance gastropods, cephalopods, brachiopods and also trilobites.
The trilobites Lonchodomas balticus and Lonchodomas portlocki are most common. In addition, many skeletal parts of Tretaspis seticornis were found. A lot of more or less complete specimens, mostly enrolled, were prepared. The author reports on his experiences during preparation. The lecture includes remarks on morphology and the life style of Tretaspis seticornis.

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Enrollment of the earliest trilobites

Presenter: Helje Pärnaste

Trilobites had the articulated exoskeleton enabling to enroll their body and hide their soft parts. This defence mechanism is known on most trilobite groups but the complete enrollment is questioned for some earliest ones. The records of the enrolled early Cambrian trilobites are extremely rare.

One recent study on exceptionally preserved middle Cambrian trilobite assemblage in Purujosa, Spain shows that encapsulated enrollment was functionally possible for Cambrian trilobites belonging to a wide variety of morphologies. However the earliest known completely enrolled ( i.e. covering the entire underside of the head shield with the ventrally flexed trunk) early Cambrian trilobite, the olenellid Mummaspis in Alberta is not encapsulating.

Here, a new record of enrolled Schmidtiellus from the early Cambrian Lükati Formation in Estonia demonstrates the ancestral state of the enrollment with its incomplete coverage of the side lobes.

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Hypostomes in Cambrian agnostids from the Barrandian area (Czech Republic)

Presenter: OLDŘICH FATKA  & VLADISLAV KOZÁK

Remains of agnostid hypostomes are rare and have been reported in about fifty specimens assigned to ten Cambrian species. A large collection of Cambrian skeletal fauna from the Barrandian area includes articulated agnostids with in situ preserved hypostomes in four species from the Příbram–Jince Basin and in two species from the Skryje–Týřovice Basin.

The studied material provides the first information on morphology of hypostome in the Superfamily Condylopygoidea Raymond, 1913, and in four other Cambrian agnostid genera. Undoubted remains of hypostomes are newly established in Condylopyge rex (Barrande, 1846), Peronopsis integra
(Beyrich, 1845), Onymagnostus hybridus (Brøgger, 1878) and Phalagnostus prantli Šnajdr, 1957. Possible remains of hypostomes are described in Hypagnostus parvifrons (Linnarsson, 1869) and Skryjagnostus pompeckji Šnajdr, 1957.

Hypostome without apical boss, earlier known only in Oidalagnostus trispinifer Westergård, 1946, is most probably present also in P. prantli and S. pompeckji. Earlier supposed chemical composition and placement of agnostid hypostome are briefly discussed. The three types of agnostid hypostome preservation, silicified, phosphatised, and hypostomes without chemical incrustation show an apparent relation to palaeolatitudes, if plotted in Cambrian palaeogeographical map.

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Fringe regeneration in Bohemoharpes after an injury

Presenter: Michael Zwanzig

During the last years, a lot of cephala of Bohemoharpes cf. acuminatus (Lindström 1886) from the Silurian of Gotland (Sweden) where collected and prepared. The material was exclusively found inside orthocone nautiloids. Some of the cephala show a fringe partly healed or regenerated.  
Šnajdr (1978) speculated, that the regeneration of injured parts of the fringe of Bohemoharpes went on though several moults. Zwanzig & Liebermann (2012), on base of an extraordinary finding from the Silurian of Gotland, were able to prove this conjecture of Šnajdr conclusively for the first time.

But the special construction of the fringe prevents complete regeneration of this part of the carapace. The lecture will demonstrate the structural parts of the fringe that could be regenerated as well as those which could not. The structures that could be regenerated were crucial for the survival of the animal. A strong reduction of the size of the area of the fringe, however, had no effect on survival.

ZWANZIG M. & LIEBERMANN S. (2012): A Silurian Bohemoharpes twice used an empty shell of an orthocone nautiloid as refuge for moulting. In BUDIL P. & FATKA O. (eds.), The 5th Conference on Trilobites and their relatives, p. 58, Czech Geological Survey, Prague.

ŠNAJDR M. (1978): Pathological neoplasm in the fringe of Bohemoharpes. Věstník Ústředního

Ústavu Geologického 53: 301-304.

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