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Open Access Trilobite Papers 1993–2019

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The Trilobite Papers 21 - An International Newsletter for and by Trilobite Paleontologists - February 2019 :fistbump:

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Basse, M. 2019
Contributions to Nomenclature of the Class Trilobita, 1.
The Trilobite Papers, 21:29-37

 

Basse, M., Müller, P. 2019
Refigured cast of holotype Leonaspis bassei.
The Trilobite Papers, 21:20

 

Basse, M., Müller, P. 2019
Short notes on current investigations and publications mainly on Silurian and Devonian trilobites in the Rhenohercynian Zone of the German Variscides.

The Trilobite Papers, 21:48-50

 

Lask, M. 2019
The Trilobites of Caleb Quarry.
The Trilobite Papers. 21:37-47

 

Noriega Ruiz, H.A., Cuen Romero, F.J., Monreal, R. 2019
Cambrian Trilobites in Sonora, Mexico: 78 years of research.
The Trilobite Papers, 21:13-19

 

Ruston, A.W.A., & Bir, R. 2019
The Diversity of Lower Cambrian Trilobites from North Wales.
The Trilobite Papers, 21:27-28

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Van Viersen, A.P., Taghon, P., Magrean, B. 2019

Early Middle Devonian Trilobites and events in the Nismes – Vireux-Molhain area, southern border of the Dinant Synclinorium (Belgium, northern France).

Geologica Belgica, 22(1-2):7-33

 

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Feist, R. 2019

Post-Kellwasser event recovery and diversification of phacopid trilobites in the early Famennian (Late Devonian).

Czech Geological Survey, Bulletin of Geosciences, 94(1):1-22

 

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Stocker, C.P., Siveter, D.J., Lane, P.D., Williams, M., Oji, T., Wallis, S.R., Tanaka, G., Komatsu, T., Siveter, D.J., Vandenbroucke, T.R.A. 2019
The paleobiogeographical significance of the Silurian and Devonian trilobites of Japan.
Island Arc, 28(2):e12287:1-15

 

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Zhou, Z.Q., Zhou, Z.Y. 2019
Ordovician Trilobites from the lower part of the Dawan Formation (Floian–Dapingian) at Huanghuachang, Yichang, Hubei, southern China.
Palaeoworld, 28:145-165

 

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Eaton, K.J. 2019

Lethal and sublethal predation on Cambrian trilobites from North America.

Undergraduate Research Thesis, The Ohio State University, 24 pp.

 

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Candela, Y., Crighton, W.R.B. 2019

Synoptic revision of the Silurian fauna from the Pentland Hills, Scotland described by Lamont (1978).

Palaeontologia Electronica, 22(19A):1-45

 

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Hopkins, M.J. 2019

Phylogenetic analysis and revision of the trilobite subfamily Balnibarbiinae (Olenidae).

American Museum Novitates, 3928:1-20

 

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Kaur, R., Singh, B.P., Bhargava, O.N., Singla, G., Stopden, S. 2019
Cambrian trilobite fauna of the Haydenaspis parvatya level (Series 2, Stage 4): Its stratigraphic position with respect to the Oryctocephalus indicus Biozone (Miaolingian Series, Wuliuan Stage) in the Spiti Himalaya, India. [La faune trilobite cambrienne du niveau de Haydenaspis parvatya (série2, scène 4): sa position stratigraphique par rapport à la biozone à Oryctocephalus indicus (série Miaolingien, étage Wuliuen) dans larégion de Spiti (Himalaya, Inde).] Comptes Rendus Palevol, 18:298-305

 

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Stocker, C.P., Siveter, D.J., Lane, P.D., Williams, M., Oji, T., Tanaka, G., Komatsu, T., Wallis, S., Siveter, D.J., Vandenbroucke, T.R.A. 2019

The Silurian and Devonian proetid and aulacopleurid trilobites of Japan and their palaeogeographical significance.

Fossils and Strata, 64:205-232

 

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Drage, H.B., Vandenbroucke, T.R.A., Van Roy, P., Daley, A.C. 2019

Sequence of post-moult exoskeleton hardening preserved in a trilobite mass moult assemblage from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco.

Acta Palaeontologica Polonica, 64(2):261–273

 

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Scholtz, G., Staude, A., Dunlop, J.A. 2019

Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities.

Nature Communications, 10(2503):1-7

 

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Zhao, Y., Yuan, J., Babcock, L.E., Guo, Q., Peng, J., Yin, L., Yang, X., Peng, S.C., Wang, C., Gaines, R.R., Esteve, J., Tai, T., Yang, R., Wang, Y., Sun, H., Yang, Y. 2019

Global Standard Stratotype-Section and Point (GSSP) for the conterminous base of the Miaolingian Series and Wuliuan Stage (Cambrian) at Balang, Jianhe, Guizhou, China.

Episodes, 42(2):165-184

 

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Basse, M., Lemke, U. 2019

Neue und wenig bekannte Trilobiten aus dem frühen und späten Devon des Kellerwalds (Rhenoherzynikum, Deutsche Varisziden).

[New and little-known Trilobites from the Early and Late Devonian of Kellerwald (Rhenohercynian Zone, German Variscides).]

Dortmunder Beitrage Landeskunde, Naturwissenschaftliche Mitteilungen, 49:47-69  OPEN ACCESS PDF

 

Basse, M., Müller, P., Habenicht, J. 2019

Heliopeltis und Sagittapeltis im Emsium des Rhenoherzynikums (Trilobita, Unterdevon, Deutsche Varisziden).

[Heliopeltis and Sagittapeltis in the Emsian of the Rhenohercynian Zone (Trilobita, Early Devonian, German Variscides).]

Dortmunder Beitrage Landeskunde, Naturwissenschaftliche Mitteilungen, 49:71-91  OPEN ACCESS PDF

 

Müller, P., Hahn, G. 2019

Eine Neue Trilobiten-Fauna aus dem Mississippium von Rösenbeck (Nordrhein-Westfalen, Deutschland).

[A New Trilobite Fauna from the Mississippian of Rösenbeck (North Rhine-Westphalia, Germany).]

Dortmunder Beitrage Landeskunde, Naturwissenschaftliche Mitteilungen, 49:93-161  OPEN ACCESS PDF

 

Drage, H.B. 2019

Quantifying Intra- and Interspecific Variability in Trilobite Moulting Behaviour Across the Palaeozoic.

Palaeontologia Electronica, 22(2):1-39  OPEN ACCESS PDF

 

 

Hot off the press: NAPC 2019 Trilobite Abstracts and Postersmail?url=http%3A%2F%2Fmail.yimg.com%2Fok%2Fu%2Fassets%2Fimg%2Femoticons%2Femo57.gif&t=1561412894&ymreqid=23281213-8dc1-3cff-1c09-5d000301c300&sig=mFTyjYS_lZdLu7hpVdyQgg--~C

 

In: Droser, M.L., Hughes, N.C., et al. (eds.) 2019

11th North American Paleontological Conference Program with Abstracts.

PaleoBios, 36(Supplement 1):1-389 

 

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Adrain, J.M. 2019
Two Laurentian Tremadocian (Early Ordovician) Mass Extinctions.
 

Babcock, L.E., Kastigar, J., Petaya, J., Eaton, K., Sheets, J. 2019
Three-Dimensional Preservation of Nonbiomineralized Tissues in Cambrian Concretionary Lagerstätten of North America.

 

Bradley, A., Adrain, J.M. 2019
Politicurus and Related Genera of Hintzecurine Trilobites from the Late Skullrockian (Tremadocian: Early Ordovician) of Western Utah and Southeastern Idaho.

 

Budd, G.E. 2019
Richard Fortey: An Unauthorised Biography.

 

Corrales, A., Esteve, J., Zhao, Y., Yang, X. 2019
Synchronized Molting Behavior in Early Cambrian Trilobites.

 

Eaton, K.J., Babcock, L.E. 2019
Patterns of Lethal and Sublethal Predation on Cambrian Stage 3-Drumian Stage Trilobites from the Great Basin, USA.

 

Esteve, J., Rubio, P., Burashi S.L., 2019
Gaits Modelling and Computational Fluid Dynamic Simulation Suggest Multiple Functional Behaviors in Trilobites.

 

Esteve, J., Zhao, Y., Yang, X., Álvaro, J.J. 2019
Morphological Variation as Consequence of Abiotic Factors in Early Trilobites.

 

Fortey, R.A., Ebbestad, J.O.R. 2019
The Best of Two Worlds - The Late Ordovician Trilobites of the Taimyr Peninsula, Arctic Russia.

 

Foster, J.R. 2019
Comparative Trilobite Taphonomy of the Pioche Formation lagerstätte and other formations along a nearshore to outer shelf transect, latest early Cambrian (Stage4; late Dyeran) of the Southern Great Basin.

 

Holmes, J.D., Paterson, J.R., García-Bellido, D.C. 2019
Ontogeny of the Trilobite Estaingia bilobata from the Cambrian Series 2 (Stage 4) Emu Bay Shale, South Australia.

 

Hong, P.S. 2019
Digitization of Three-Dimensional Surface Morphology of Millimeter-Scale Fossil Specimens through Focus Stacking and Photogrammetry Techniques.

 

Hopkins, M.J. 2019
Comparison of Growth Rates in the Trilobites Elrathia kingii (Meek, 1870) and Aulacopleura koninckii (Barrande, 1846).

 

Hou, J.B., Hughes, N.C. 2019
Mathematic Modeling to Reconstruct the Taphonomic History of the Burgess Shale-Type Fossils.

 

Kimmig, J., Strotz, L., Egenhoff, S., Lieberman, B.S. 2019
The Middle Cambrian Spence Shale (Miaolingian: Wuliuan) Lagerstätte: Improving our Understanding of a Key Cambrian Ecosystem.

 

Laibl, L., Maletz, J., Olschewski, P., Daley, A.C. 2019
Post-Embryonic Development of Fritzolenellus Reveal Ancestral Morphology of Early Developmental Stages in Trilobita.

 

Lerosey-Aubril, R., Comfort, D., Skabelund, J., Weug, A., Zhao, W., Ortega-Hernãndez, J. 2019

Evolution of the Digestive System in Cambrian Trilobites.

 

Loch, J.D., Taylor, J.F., Repetski, J.E. 2019
Lotagnostus species from the Cambrian (Furongian) Windfall Formation, Nevada, and their significance regarding on the GSSP for Cambrian Stage 10.

 

Losso, S.R., Ortega-Hernãndez, J. 2019
Taphonomy of the Phacopid Trilobites Ceraurus pleurexanthemus and Flexicalymene senaria from the Walcott-Rust Quarry (Upper Ordovician).

 

Ng, R., Adrain, J.M. 2019
Phylogeny of an Enigmatic and Distinct Clade of Cambro-Ordovician Trilobites from Laurentia with New and Revised Species of Clelandia.

 

Olson, H.C. 2019
Review of the Middle Cambrian Trilobites of the Bathyuriscus-Elrathina biozone of Montana: Taphonomy and Taxonomic Information.

 

Paterson, J.R., Edgecombe, G.D., Lee, M. 2019
Trilobites in Cruise Control: Clocking their Evolutionary Rates and the end of the Cambrian Explosion.

 

Pearson, K., Hubbard, K., Cruz, Y. 2019
Experimental Biomechanics of Trinucleid Fringe Pits (Trilobita).

 

Peng, S.C., Yang, X., Liu, Y. 2019
Discovery of a New Exceptional Preserved Cambrian Biota from the Longha Formation in Southeastern Yunnan.

 

Perez-Peris, F., Laibl, L., Vidal, M., Daley, A.C. 2019
Morphology and evolution of basal Cheirurina (Trilobita) from the Fezouata Biota (Lower Ordovician, Morocco).

 

Schoenemann, B. 2019
A Look into the Eyes of Trilobites.

 

Vargas-Parra, E.E., Hughes, N.C. 2019
Exploring Variation in Late Cambrian Trilobite Dikelocephalus pygidia using Landmark-Based Geometric Morphometrics.

 

Vayda, P., Babcock, L.E., Oti, E., Wiedman, L. 2019
Exceptionally Preserved Fossils from the Silica Shale Lagerstätte (Middle Devonian) of Ohio, Michigan, and Indiana: XCT Reveals Detailed Anatomical Information.

 

Wernette, S.J., Hughes, N.C., Myrow, P.M., Sardsud, A., McKenzie, N. 2019
Improved Biostratigraphy for the Tarutao Group, Thailand and its Global Significance.

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Corbacho, J., Morrison, S., Llácer, S., Hammond, K., 2019

Use of CT Scanning and Radiography as Legal Expert Evidence in Paleontology (Trilobites of Morocco).

American Journal of Life Sciences, 7(2):47-53

 

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FossilDAWG
2 hours ago, piranha said:

Corbacho, J., :yay-smiley-1: Morrison, S., :yay-smiley-1: Llácer, S., Hammond, K., 2019

Use of CT Scanning and Radiography as Legal Expert Evidence in Paleontology (Trilobites of Morocco).

American Journal of Life Sciences, 7(2):47-53

Congratulations on another nice publication!

 

Don

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piranha
On 7/26/2019 at 11:57 AM, FossilDAWG said:

Congratulations on another nice publication!

 

Don

 

 

Thanks! mail?url=http%3A%2F%2Fmail.yimg.com%2Fok%2Fu%2Fassets%2Fimg%2Femoticons%2Femo31.gif&t=1564332462&ymreqid=23281213-8dc1-3cff-1cba-310003014300&sig=E9O9i6bno6hmpOBasmLEUg--~C 

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piranha

Trilobite abstracts from:

 

STRATI 2019: The 3rd International Congress on Stratigraphy, July 2–5, 2019, Milan, Italy, Abstract Book  OPEN ACCESS PDF reading-smiley.gif?1292867661

 

Babcock, L.E., Peng, S.C., Ahlberg, P., Zhang, X.L., Zhu, M.Y., Parkhaev, P.Y. 2019

A Model for Subdividing Cambrian Stages into Substages. p. 142

 

Collantes, L., Gozalo, R., Mayoral, E., Garzón, I., Liñán, E. 2019

The family Atopidae (Trilobita) in the upper Marianian (Lower Cambrian) from the Ossa-Morena zone (SW Spain). p. 144

 

Gogin, I.Y., Pegel, T.V. 2019

Upper Cambrian GSSPs and their correlation to regional stratigraphic subdivisions in Asian Russia. p. 144

 

Gozalo, R., Chrivella, Martorell, J.B., Dies Álvarez, M.E., Liñán, E. 2019

Trilobites biostratigraphy of the Wuliuan Stage in the Iberian Chains (NE Spain). p. 147

 

Nielsen, A.T., Ahlberg, P. 2019

The Miaolingian Series and the traditional ‘Middle’ Cambrian: implications for Baltoscandian stratigraphy. p. 150

 

Park, T.Y., Lee, M., Kihm, J.H., Nielsen, M.L., Vinther, J., Nielsen, A.T. 2019

New collection of Sirius Passet biota, Peary Land, North Greenland, and its implication for the age. p. 153

 

Parkhaev, P.Y., Demidenko, Y.E., Kulsha, M.A. 2019

Better one-eyed than stone-blind: choosing the index species for the base of Cambrian Stage 3. p. 154

 

Peng, S.C., Babcock, L.E., Bagnoli, G., Shen, Y., Mei, M., Zhu, X., Li, D., Zhang, X., Wang, L. 2019

Proposed GSSP for Cambrian Stage 10 with multiple stratigraphic markers for global correlation. pp. 157-158

 

Ray D.C., Hughes H.E., Jarochowska E., Claussen A.L. 2019

The stratigraphy and correlation of the Wenlock Series of Radnorshire (Wales): preliminary results. p. 177

 

Wang, Z.H., Niu, Z.J., Yao, H.Z. 2019

Progress in the Ordovician stratigraphy of the Yunkai area, South China. p. 451

 

Yang, X., Zhao, Y., Cao, P., Wei, B. 2019

The Niutitang Formation from the Cambrian in Guizhou. p. 159

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:trilo: TRILOBITE ABSTRACTS:  GEOLOGICAL SOCIETY OF AMERICA — ANNUAL MEETING — PHOENIX, ARIZONA, USA - SEPTEMBER 22–25, 2019 :trilo:

 

 

SECRETS OF THE HARPETIDS: PHYLOGENY, DISPARITY, AND MASS EXTINCTION RESPONSE IN THE TRILOBITE ORDER HARPETIDA

Beech, J., Lamsdell, J.C. 2019. Geological Society of America,  Abstracts with Programs, GSA 331579 – Paper No. 194-1 (GSA Annual Meeting, Phoenix, Arizona)

 

This study seeks to better understand the phylogenetic relationships within the trilobite order Harpetida, with a view towards using this group to explore the relationship between extinction intensity and disparity. The harpetid response to the Late Ordovician mass extinction is of particular interest. A discrete morphological character matrix was created from the formal descriptions of harpetids in the published trilobite literature, and refined using first-hand observations of harpetid fossils. The final matrix consists of 76 discrete characters, including 69 cephalic characters, three thoracic characters, and four pygidial characters. This matrix is the first attempt of its kind to characterize the morphology of Harpetida as a whole, rather than focusing on individual harpetid genera.

 

Exemplar species from a broad selection of harpetid genera, along with ptychopariid and redlichiid out groups, are included in the matrix. These taxa were coded from published figures and from direct observation of specimens held in the collections of the Yale Peabody Museum of Natural History. From the matrix, a hypothetical tree of harpetid phylogenetic relationships was generated. The topology of this tree indicates support for harpetid monophyly but throws doubt onto the previous hypotheses of the internal relationships of the group. Disparity analysis of Harpetida reveals a significant decline in morphological diversity across the Late Ordovician mass extinction boundary, with slow recovery beginning in the Silurian and continuing into the Devonian.

 


A REFERENCE COLLECTION OF DEVONIAN ARTHROPODS (TRILOBITES) FROM THE GEER ROAD QUARRY IN EATON, NEW YORK
Castiblanco, U.D., Domack, C.R., Tollerton, V.P. 2019. GSA 328045 – Paper No. 17-3 (GSA Northeastern Section - 54th Annual Meeting)

 

We constructed an educational reference collection of Middle Devonian trilobites found at the Geer Road Quarry in Eaton, New York. The Geer Road Quarry is known for its rich abundance and diversity of invertebrate fossils in Upper Hamilton Group, Moscow Formation shales. Three genera of trilobites were obtained (Greenops, Eldredgeops, and Dipleura) with Greenops being the most abundant. The collection features over 25 specimens (mostly body segments). The purpose of the reference collection is to assist students and members of the community with identification of trilobite fossils at the quarry.

 


LONG-DISTANCE LATERAL VARIABILITY IN BIOTAS AND LITHOLOGIES OF THE CAMBRIAN BRIGHT ANGEL FORMATION (TONTO GROUP), GRAND CANYON, USA

Foster, J.R., Sundberg, F.A., Karlstrom, K.E., Schmitz, M.D., Mohr, M.T., Hagadorn, J.W. 2019. Abstracts With Programs, GSA 336319 – Paper No. 160-2 (GSA Annual Meeting, Phoenix, Arizona)

 

The Bright Angel Formation of the Grand Canyon of the southwestern United States contains significant biotas of arthropods and other fossils that were collected primarily by Charles Walcott and E. D. McKee in the late 19th and early 20th centuries. New collections, the first major ones in 70 years, add to this picture. Biotas include diverse trilobites, hyoliths, brachiopods, eocrinoids, and bradoriid arthropods; trilobites and brachiopods are relatively abundant throughout the formation. Samples from large sites with 100-500+ specimens are diverse but are often dominated by dolichometopid trilobites, primarily “Anoriatontoensis, Glossopleura mckeei, and G. walcotti; ptychopariid trilobites are rare (0-15% of samples). Bradoriid arthropods (Dielymella and Walcottella) occur at just two historical localities plus at least two new (2019) localities, all occurring at sites stretching from Bass Trail east to Marble Canyon; these bivalved arthropods in some cases are the most abundant fossils at their respective localities but also occur with dolichometopid trilobites and can constitute a substantial percentage of the sample at each locality. Olenellus Zone species are known near the base of the section from Frenchman Mountain east to Granite Park; Glossopleura Zone trilobites occur high in the section in the west and low in the east and most of the Bright Angel Formation appears to be within the Glossopleura Zone. Regional changes, from western outcrops at Frenchman Mountain and Grand Wash Cliffs to the eastern-most exposures in Marble Canyon, demonstrate several patterns in the distribution of fossils and facies. Shales dominate western outcrops and the unit transitions to increasing abundance of sandstone eastwards, with far eastern sections (e.g., Marble Canyon) dominated by thin beds of sandstone and sandy siltstone with abundant detrital mica and rare thin shale interbeds suggesting proximity to the paleoshoreline. Detrital zircons in the underlying Tapeats Sandstone show the Bright Angel Formation to be < 508 Ma across the entire transect. Global calibration of the Glossopleura Zone suggests most of the Bright Angel Formation was deposited between 506 and 504 Ma. The long-proposed time-transgressive nature of the formation is supported by the Olenellus Zone being only in the west, but the timeframe for time-transgression likely involved only 1-2 million years.

 


PRESERVATION OF THE BURGESS SHALE BIOTA FROM MARBLE CANYON
Gaines, R.R., Caron, J.B., Hammarlund, E., Holzer, I., Lombardo, A.J., Canfield, D.E. 2019. Abstracts with Programs, GSA 341362 – Paper No. 1-3 (GSA Annual Meeting, Phoenix, Arizona)

 

The Marble Canyon biota of the Burgess Shale is one of the richest new Cambrian fossil deposits to be discovered in decades. Here, we review new geochemical, sedimentologic and paleontologic datasets to explore the circumstances surrounding the preservation of the Marble Canyon biota. Comprehensively, the data support the unique biostratinomic setting at the front of the Cathedral Escarpment as the most important control on the remarkable density and fidelity of preservation of soft-bodied fossils relative to other deposits. Taphonomic analyses confirm that gross morphology is captured by thin carbonaceous remains and mineral films, most prominently represented by Fe-Mg oxide, a phase that is absent from Burgess Shale sites on and near Fossil Ridge. New cross-section analyses from thin sections reveal carbonaceous films of soft-bodied fossils envelop the “aluminosilicate-like” mineral films, revealing that these phases did not grow around the outsides of organisms during early burial, but instead filled voids created by high temperature volatilization of carbonaceous remains. These patterns confirm a late-stage, metamorphic origin of fossil-associated mineral films. Mechanistic models for carbonaceous preservation invoking direct physical protection of organic carcasses from microbial decay are not supported. Geochemical and sedimentologic data further exclude the possibility that soft-bodied fossils were buried below the zone of sulfate reduction either during initial burial or subsequently during early fossilization. Sulfur isotope data illustrate that intensity of sulfate reduction in the early burial environment was more strongly influenced by intermittent weak bioturbation -which corresponds to a sharp reduction in the abundance and fidelity of soft-tissue preservation- than to bed thickness. Preservation of the most labile tissues occurs in beds as thin as 0.7 mm, characterized by pauses in sediment accumulation and emplacement of carbonate cements at the seafloor. New data from Marble Canyon clearly reveal the role of early cements in impeding oxidant flux into sediments, thereby imposing kinetic restrictions on rates of sulfate reduction and leading to carbonaceous preservation of Burgess Shale-type fossils.

 


LOWER TO MIDDLE (LATE DYERAN–MIDDLE DELAMARAN) CAMBRIAN STRATIGRAPHY AND TRILOBITE BIOSTRATIGRAPHY OF THE MOUNT CLARK AND MOUNT CAP FORMATIONS, EASTERN MACKENZIE MOUNTAINS, NORTHWESTERN CANADA
Handkamer, N.M., Pratt, B.R., MacNaughton, R.B. 2019. Abstracts with Programs, GSA 335504 – Paper No. 1-2 (GSA Annual Meeting, Phoenix, Arizona)

 

Earliest Paleozoic strata of the eastern Mackenzie Mountains record deposition in an epicontinental basin bounded by the Canadian Shield to the present-day east and tectonic arches cored by Neoproterozoic strata to the west. In the northeastern Mackenzie Mountains, the Mackenzie Arch separates this semi-enclosed basin from the ocean-facing Selwyn Basin farther to the west. Cambrian formations deposited on the eastern side include the Mount Clark Formation at the base, overlain in turn by the Mount Cap and Saline River formations. Proximal to the arch, the Mount Clark Formation consists of cross-bedded quartz arenites, locally with Skolithos pipe rock, that were deposited as shoreface sands, which pass upwards into offshore heterolithic facies. More distal strata are heterolithic and heavily bioturbated, suggesting that the basin center lay to the east. These rocks are abruptly but conformably overlain by the mudstone-dominated Mount Cap Formation, indicating lower-energy conditions below fair-weather wave base. The Saline River Formation, which lies unconformably upon the Mount Cap Formation, consists of mudstone, gypsum, and dolomite and is interpreted to record shallowing causing restriction of the basin. Trilobite collections represent the Bonnia–Olenellus Zone through the Glossopleura Zone, indicating an age range from late Dyeran to middle Delamaran, i.e. upper Stage 4 to middle Wuliuan. The basal strata of the Mount Cap Formation are older to the east which indicates that the transgression between the Mount Clark and Mount Cap formations is diachronous. The Mount Cap Formation is dominated by outer shelf facies corynexochids broadly similar to faunas described from the southern Rocky Mountains of western Canada and the Great Basin of western USA. Stratigraphic differences in the degree of fossil articulation suggest subtle bathymetric changes through time. At least two corynexochid taxa have a significantly reduced number of thoracic segments and appear to be new species endemic to the basin, suggesting peripatric speciation involving heterochronic developmental changes. This may have been induced by environmental stressors, such as water temperature or oxygenation.

 


“OLD FASHIONED” STRATIGRAPHY: THE TEST OF PALEOGEOGRAPHIC RECONSTRUCTIONS OF AVALONIA, “GANDERIA,” AND CADOMIA
Landing, E., Geyer, G., Westrop, S.R. 2019. Abstracts With Programs, GSA 336321 – Paper No. 243-4 (GSA Annual Meeting, Phoenix, Arizona)

 

Reports on the Avalonia terrane in the Acadian‒Caledonian (A‒C) mountain belt often feature 1) an homage to a complex late Proterozoic basement and siliciclastic-dominated terminal Edicaran‒Ordovician platform cover sequence (E‒O cs) with distinctive macrobiotas; 2) sophisticated zircon/stable isotope work as a prelude to geologic history conclusions; and 3) a disregard of the remarkably consistent E‒O cs along Avalonia. Sedimentary successions reflect unique interactions of factors (i.e., sediment sources, epeirogeny, eustasy, climate), but relevance of the E‒O cs to Avalonia’s geologic history is even dismissed in reports as somehow appearing on separate, later-amalgamated terranes. Emphasizing differences in basement geology has led to naming of “terranes” even within Avalonia. As we documented elsewhere, local E‒O cs reflect Avalonian transtensional history. The NE belt (marginal platform) has a ca. 15 Ma basal succession (terminal Ediacaran rift‒overlying siliciclastic shelf‒middle Early Cambrian quartz tidalite) capped by a 10‒15 Ma hiatus and late Early Cambrian siliciclastics (S. Wales; Burin, SE Nfld; Saint John‒Long Reach‒Beaver Harbour, N. B.). In SE areas (inner platform), the tidalite is unconformably overlain by older sub-trilobitic mudstone, then a 0.5‒6 m terminal subtrilobitic limestone, and unconformably overlying trilobitic mudstone (England; Avalon‒Burin, Nfld; Mira Allochthon and Doctor’s Brook authochthon, N. S.; Cradle Brook, N. B.; eastern MA). Local marginal platform developments include elevated blocks and/or Early‒Middle Cambrian boundary volcanism (Bourinot belt, Cape Breton; Malignant Cove autochthon, N. S.; Beaver Harbour, N. B.). E‒O cs provide little information on provenance of Proterozoic and older basement rocks, but indicate: 1) the Caledonia, Brookville, most of the (composite) New River, the Mira, and Bourinot (of the SE Bras d’Or area) “terranes” are simply Avalonian, no evidence supports assignment of the Brookville and SE New River blocks to “Ganderia;” 2) E‒O cs distinct lithology and biotas through the Cambrian’s first 20 Ma require Avalonia‒tropical Gondwana (Cadomia) separation by the terminal Ediacaran, not Ordovician, 3) E‒O cs lithologic differences with “Ganderia” successions (particularly Gander area) and Laurentian-aspect trilobites (“Ehmaniella”) in “Ganderian” Nfld and Columbia are problems for a “unified” Cambrian “Ganderia.”


 

A PHYLOGENETIC FRAMEWORK FOR THE SUBORDER AGNOSTINA
Lavine, R.J. 2019. Abstracts With Programs, GSA 336103 – Paper No. 14-6 (GSA Annual Meeting, Phoenix, Arizona)

 

Agnostina is a moderately diverse group of arthropods comprised of at least 12 recognized families and over 100 genera that span the middle Cambrian to the Late Ordovician. The conserved morphologies of these enigmatic organisms and their lack of reliable diagnostic characters result in an unstable systematic classification and difficulty in testing phylogenetic relationships between ingroup taxa. A total of 51 taxa from 11 agnostine families, including some taxa that currently lack formal classification, were coded for a set of 82 characters that describe the range of morphological variation within the suborder. While Bayesian methods are becoming commonplace in paleontological investigations, there is a dearth of studies that use these probabilistic methods to explore relationships in entirely extinct clades. The fossilized birth-death (FBD) process allows for a more realistic tree model that incorporates aspects of paleontological data such as estimations of speciation and extinction dynamics, preservation, and sampling as a set of priors. In this study, I propose an MCC tree for Agnostina that shows strong crownward posterior support, reaffirming the majority of currently recognized taxonomic families with the notable exception of Pseudagnostidae. This tree provides a framework for continuing research into developmental constraints that may shape macroevolutionary patterns in this biostratigraphically important group of arthropods.

 

 

POLYMERID TRILOBITES OF THE MANUELS RIVER FORMATION, NEWFOUNDLAND, CANADA
Unger, T., Austermann, G., Hildenbrand, A. 2019. Abstracts with Programs, GSA 331769 – Paper No. 271-2 (GSA Annual Meeting, Phoenix, Arizona)

 

Trilobites are among the best studied and most important index fossils of the middle Cambrian. With this contribution we show preliminary results of the systematic revision of the polymerid trilobite fauna from the type locality of the Drumian (middle Cambrian, Series 3) Manuels River Formation, Conception Bay South, Newfoundland, Canada. The fossil-rich grey to black shales with minor interbedded calcareous concretions were deposited on the former microcontinent Avalonia and show features of a typical condensed succession. In part the fossils show pyritization due to the oxygen depleted environment and diagenetic impact. The containing fauna consists of trilobites, brachiopods, hyoliths and acritarchs.

 

Previous studies were mainly taken several decades ago and focused on different aspects. The original description of the stratigraphy and trilobite fauna at the type locality of the Manuels River Formation was done by Howell in 1925. In 1962, Hutchinson revised and refined the Cambrian lithostratigraphy and trilobite systematics in southeastern Newfoundland, which included the trilobite fauna in Conception Bay South. The herein studied well-preserved specimens are part of a new collection, sampled bed by bed from the c. 20 m thick succession, consisting mainly of articulate cephali, several pygidia, and broken segments. The polymerid trilobites are mainly assigned to the Order Ptychopariida.

 


ASHES AND TRILOBITES IN THAILAND: THE KEY TO DATING THE CAMBRIAN-ORDOVICIAN BOUNDARY
Wernette, S.J., Hughes, N.C., Myrow, P.M., Sardsud, A. 2019. Abstracts with Programs, GSA 336701 – Paper No. 1-4 (GSA Annual Meeting, Phoenix, Arizona)

 

Sibumasu (the Shan-Thai Block) was a peri-Gondwanan terrane that flanked equatorial Gondwana’s northern margin during the late Cambrian and early Ordovician. Along with the North and South China, Lhasa, Qiantang, Tarim, and Indochina blocks, Sibumasu lay outboard of the eastern Gondwanan core comprising India-Antarctica-Australia in some configuration, the details of which are yet to be determined. The Tarutao Group outcropping in southern-most Thailand is Sibumasu’s best exposed, most continuous and accessible unit spanning the Cambrian-Ordovician boundary and uniquely comprises a sequence of interbedded fossiliferous sandstones and rhyolitic tuffs. Age-equivalent units elsewhere in Sibumasu include the Machinchang Formation of Malaysia, the Molohein Group and Pangyun Formation of the Shan States of Myanmar, and the Baoshan Formation of western Baoshan in southwest Yunnan, China. Recent work on the Tarutao Group has recovered new late Cambrian and early Ordovician trilobite taxa, including a new genus, Satunarcus, and other genera not previously recovered from Sibumasu including Haniwa, Apatokephalus, and Wuhuia. The expanded collection of taxa and the inclusion of new field localities and stratigraphic units facilitate improved biostratigraphic and paleogeographic correlation between Sibumasu and associated Gondwanan terranes. Sibumasu’s multiple datable ashes collectively span a significant portion of the latest Cambrian and the Cambrian-Ordovician boundary. They will permit age calibration of the Gondwanan biostratigraphic record in what is currently one of the most poorly dated intervals of Phanerozoic history. They will also allow assessment of the rates of evolutionary change during the transition from the Cambrian fauna to the establishment of the Paleozoic fauna in the Ordovician. The genus-level similarities of the Tarutao fauna with both Korean fauna and Australian aids in stratigraphic correlation and also finally resolving the configuration of peri-Gondwanan terranes, the reconstruction of which is supported by detrital zircon records.

 


A PHYLOGENETIC FRAMEWORK FOR THE FAMILY PHACOPIDAE (TRILOBITA) BASED ON BAYESIAN INFERENCE METHODS
Witte, M.K. 2019. Abstracts With Programs, Gsa 340047 – Paper No. 14-8 (Gsa Annual Meeting, Phoenix, Arizona)

 

Arguments over the degree of taxonomic splitting, genera plagued by wastebasket taxa, and a relatively conserved morphology have left the systematics of the trilobite family Phacopidae in a state of disarray. Few published phylogenetic frameworks encompass the diversity of the group. Complex patterns of morphologic similarity between taxa complicate the distinction of synapomorphy from symplesiomorphy and/or homoplasy. Several species behave as ‘rogue taxa,’ being volatile in hypothesized phylogenetic placement—especially among analyses employing different methods or emphasizing different character sets—so that polytomies are common and phylogenetic resolution is low. These factors have resulted in unstable higher-level taxa.

 

Over the last decade, advances in Bayesian inference methods have revolutionized phylogenetic analysis of morphological data. Analyses of simulated datasets have shown that Bayesian inference methods may outperform parsimony-based methods in recovering phylogenetic trees. Though Bayesian methods are becoming more commonplace in paleontology, they usually combine extant and extinct species within a single framework and few studies have investigated fossil-only datasets using these methods.

Here, I apply Bayesian inference methods, using the Fossilized Birth-Death process as a model framework, to construct a phylogenetic tree of Phacopidae. This study encompasses 65 species representing four of the five major tribes and 68 characters representing all regions of the trilobite exoskeleton. I propose an MCC tree that shows strong crownward posterior support for recovered clades. Even after degradation of the dataset, these crownward relationships remain stable, suggesting a greater degree of phylogenetic signal compared to previous studies. The proposed tree offers a framework upon which future phylogenetic studies may build and macroevolutionary studies may be conducted.

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Blackwell, S.R. 2019

Cambrian (Jiangshanian; Sunwaptan) Trilobites From the Upper Honey Creek Formation, Wichita Mountains Region, Oklahoma.

MSc Thesis, University of Oklahoma, 144 pp.

 

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Caprichoso, C.C. 2019

Trilobites Calymenina do Devónico de Portugal – uma Revisão.

[Trilobites Calymenina of the Devonian of Portugal - a Review.]

MSc Thesis, Faculdade de Ciências Tecnologia, Universidade Nova de Lisboa, 367 pp.

 

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Ebbestad, J.O.R., Fortey, R.A. 2019

Late Ordovician Trilobites from the Taimyr Peninsula, Arctic Russia.

Journal of Systematic Palaeontology, (in press) 135 pp.

 

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:trilo: The Trilobite Papers 22 - An International Newsletter for and by Trilobite Paleontologists - August 2019 :trilo:

 

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Basse, M., Müller, P., Müller, M. 2019
Reference to: Basse, M. & Müller, P. 2019. Neues zu Trilobiten der Gattung Psychopyge aus dem Rupbach-Schiefer der Lahnmulde.

Fossilien, Journal für Erdgeschichte, 03/19: 54–57. pp. 30-31

 

Faucher, K.X. 2019
Illustrating Trilobites. pp. 14-19

 

Fowler, E., Damiani, P. 2019
Field Notes: Cirquella n. sp. of Lower Montenegro Member, Nevada: A Preliminary Report. pp. 5-7

 

Geyer, G. 2019
Early Expeditions Into Morocco’s Past: The First Discoveries of Cambrian Trilobites in Africa.  pp. 20-29

 

Scholten, P. 2019
Miniature Trilobites. pp. 7-9

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:trilowalk: 13th International Symposium on the Ordovician System :trilowalk:

 

Sennikov, N.V., Obut, O.T., Lykova, E.V., Timokhin, A.V., Gonta, T.V., Khabibulina, R.A., Shcherbanenko, T.A., Kipriyanova, T.P. 2019

Ordovician Sedimentary Basins and Paleobiotas of the Gorny Altai. 13th International Symposium on the Ordovician System, 184 pp.

Trofimuk Institute of Petroleum Geology,and Geophysics SB RAS: Novosibirsk National Research State University – Novosibirsk : Publishing House of SB RAS

 

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Kanygin, A.V. Dronov, A.V., Gonta, T.V., Timokhin, A.V., Maslova, O.A. 2019

Ordovician of the Tungus Basin (Siberian Platform). 13th International Symposium on the Ordovician System. Field Excursion Guidebook, 62 pp.

Trofimuk Institute of Petroleum Geology and Geophysics SB RAS: Novosibirsk National Research State University – Novosibirsk : Publishing House of SB RAS

 

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Obut, O.T., Sennikov, N.V., Kipriyanova, T.P. (eds) 2019

Contributions of International Symposium. 13th International Symposium on the Ordovician System. Novosibirsk, Russia, Abstracts & Proceedings, 263 pp.

Trofimuk Institute of Petroleum Geology and Geophysics SB RAS: Novosibirsk National Research State University – Novosibirsk : Publishing House of SB RAS

 

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Brodskii, A.V., G.N. Kiselev, G.N. 2019

The Trilobite and Cephalopod Taxonomic Diversity From Kunda Stage Deposits of the Northeastern Part of the Baltic-ladoga Glint. p. 19

 

Sennikov, N.V., Gusev, N.I., Tokarev, V.N., Yur’ev, A.A., Timokhin, A.V., Khabibulina, R.A., Gonta, T.V., Shcherbanenko, T.A., Gutak, Y.M. 2019

The O/S Boundary in Salair Volcanic-Sedimentary Deposits: Fauna, Isotopic Age (South Siberia, Russia). pp. 179-180

 

Sobolevskaya, R.F., Nekhorosheva, L.V. 2019

Ordovician Deposits of Kotelny Island (New Siberian Islands). pp. 193-196

 

Timokhin, A.V., Gonta T.V., Maslova O.A. 2019

Biodiversity of Benthic Fauna (Trilobites, Brachiopods, Ostracods) in the Ordovician of the Siberian Platform. Poster Presentation

 

Zhang, Y.D., Zhan, R.B., Zhen, Y.Y., Fang, X., Yuan, W.W., Zhang, J.P., Li, W.J. 2019

An Integrative Stratigraphy for the Ordovician System of China: Framework and Questions. pp. 249-252

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Bruthansová, J. 2019
Preliminary report on the study of ontogeny and taphonomy of trilobite Onnia superba (Bancroft, 1929) from the Bohemian Ordovician (Katian, Bohdalec Formation).

Geoscience Research Reports, Czech Geological Survey, 52:125-128

 

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Bicknell, R.D., Paterson, J.R., Hopkins, M.J. 2019

A trilobite cluster from the Silurian Rochester Shale of New York: predation patterns and possible defensive behavior.

American Museum of Natural History, Novitates, 3937:1-16

 

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Jacobs, G.S., Carlucci, J.R. 2019

Ontogeny and shape change of the phacopid trilobite Calyptaulax.

Journal of Paleontology (ahead-of-print publication) 21 pp.

 

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Chatterton, B.D.E., Gibb, S., McKellar, R.C. 2019

Species of the Devonian aulacopleurid trilobite Cyphaspides from southeastern Morocco.

Journal of Paleontology, (ahead-of-print publication) 16 pp.

 

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Høyberget, M., Ebbestad, J.O.R., Funke, B. 2019

Re-evaluation of the stratigraphically important olenellid trilobite Holmia cf. mobergi from the Cambrian Series 2, Stage 3 and its implications for the lower Cambrian stratigraphy in the Mjøsa area, Norway. Norwegian Journal of Geology, 99(1):1-29

 

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