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'Placoderm' (Arthrodira)
Jobbins et al. Swiss J Palaeontol (2021) 140:2 https://doi.org/10.1186/s13358-020-00212-w Swiss Journal of Palaeontology RESEARCH ARTICLE Open Access A large Middle Devonian eubrachythoracid ‘placoderm’ (Arthrodira) jaw from northern Gondwana Melina Jobbins1* , Martin Rücklin2, Thodoris Argyriou3 and Christian Klug1 Abstract For the understanding of the evolution of jawed vertebrates and jaws and teeth, ‘placoderms’ are crucial as they exhibit an impressive morphological disparity associated with the early stages of this process. The Devonian of Morocco is famous for its rich occurrences of arthrodire ‘placoderms’. While Late Devonian strata are rich in arthrodire remains, they are less common in older strata. Here, we describe a large tooth-bearing jaw element of Leptodontich- thys ziregensis gen. et sp. nov., an eubrachythoracid arthrodire from the Middle Devonian of Morocco. This species is based on a large posterior superognathal with a strong dentition. The jawbone displays features considered syna- pomorphies of Late Devonian eubrachythoracid arthrodires, with one posterior and one lateral row of conical teeth oriented postero-lingually. μCT-images reveal internal structures including pulp cavities and dentinous tissues. The posterior orientation of the teeth and the traces of a putative occlusal contact on the lingual side of the bone imply that these teeth were hardly used for feeding. Similar to Compagopiscis and Plourdosteus, functional teeth were pos- sibly present during an earlier developmental stage and have been worn entirely. The morphological features of the jaw element suggest a close relationship with plourdosteids. Its size implies that the animal was rather large. Keywords: Arthrodira, Dentition, Food web, Givetian, Maïder basin, Palaeoecology Introduction important to reconstruct character evolution in early ‘Placoderms’ are considered as a paraphyletic grade vertebrates. -
Redescription of Yinostius Major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the Interrelationships of Brachythoraci
bs_bs_banner Zoological Journal of the Linnean Society, 2015. With 10 figures Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci YOU-AN ZHU1,2, MIN ZHU1* and JUN-QING WANG1 1Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China 2University of Chinese Academy of Sciences, Beijing 100049, China Received 29 December 2014; revised 21 August 2015; accepted for publication 23 August 2015 Yinosteus major is a heterostiid arthrodire (Placodermi) from the Lower Devonian Jiucheng Formation of Yunnan Province, south-western China. A detailed redescription of this taxon reveals the morphology of neurocranium and visceral side of skull roof. Yinosteus major shows typical heterostiid characters such as anterodorsally positioned small orbits and rod-like anterior lateral plates. Its neurocranium resembles those of advanced eubrachythoracids rather than basal brachythoracids, and provides new morphological aspects in heterostiids. Phylogenetic analysis based on parsimony was conducted using a revised and expanded data matrix. The analysis yields a novel sce- nario on the brachythoracid interrelationships, which assigns Heterostiidae (including Heterostius ingens and Yinosteus major) as the sister group of Dunkleosteus amblyodoratus. The resulting phylogenetic scenario suggests that eubrachythoracids underwent a rapid diversification during the Emsian, representing the placoderm response to the Devonian Nekton Revolution. The instability of the relationships between major eubrachythoracid clades might have a connection to their longer ghost lineages than previous scenarios have implied. © 2015 The Linnean Society of London, Zoological Journal of the Linnean Society, 2015 doi: 10.1111/zoj.12356 ADDITIONAL KEYWORDS: Brachythoraci – Heterostiidae – morphology – phylogeny – Placodermi. -
The Earliest Phyllolepid (Placodermi, Arthrodira) from the Late Lochkovian (Early Devonian) of Yunnan (South China)
Geol. Mag. 145 (2), 2008, pp. 257–278. c 2007 Cambridge University Press 257 doi:10.1017/S0016756807004207 First published online 30 November 2007 Printed in the United Kingdom The earliest phyllolepid (Placodermi, Arthrodira) from the Late Lochkovian (Early Devonian) of Yunnan (South China) V. DUPRET∗ &M.ZHU Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, P.O. Box 643, Xizhimenwai Dajie 142, Beijing 100044, People’s Republic of China (Received 1 November 2006; accepted 26 June 2007) Abstract – Gavinaspis convergens, a new genus and species of the Phyllolepida (Placodermi: Arthrodira), is described on the basis of skull remains from the Late Lochkovian (Xitun Formation, Early Devonian) of Qujing (Yunnan, South China). This new form displays a mosaic of characters of basal actinolepidoid arthrodires and more derived phyllolepids. A new hypothesis is proposed concerning the origin of the unpaired centronuchal plate of the Phyllolepida by a fusion of the paired central plates into one single dermal element and the loss of the nuchal plate. A phylogenetic analysis suggests the position of Gavinaspis gen. nov. as the sister group of the Phyllolepididae, in a distinct new family (Gavinaspididae fam. nov.). This new form suggests a possible Chinese origin for the Phyllolepida or that the common ancestor to Phyllolepida lived in an area including both South China and Gondwana, and in any case corroborates the palaeogeographic proximity between Australia and South China during the Devonian Period. Keywords: Devonian, China, Placodermi, phyllolepids, biostratigraphy, palaeobiogeography. 1. Introduction 1934). Subsequently, they were considered as either sharing an immediate common ancestor with the The Phyllolepida are a peculiar group of the Arthrodira Arthrodira (Denison, 1978), belonging to the Actin- (Placodermi), widespread in the Givetian–Famennian olepidoidei (Long, 1984), or being of indetermined of Gondwana (Australia, Antarctica, Turkey, South position within the Arthrodira (Goujet & Young,1995). -
Comments on the Late Devonian Placoderms from the Holy Cross Mountains (Poland)
Comments on the Late Devonian placoderms from the Holy Cross Mountains (Poland) ALEXANDER IVANOV andMICHAŁ GINTER Ivanov, A. & Ginter,M. 1997. Comments on the Late Devonian placoderms from the Holy Cross Mountains (Poland).- Acta Palaeontologica Polonica 4,3,4I34f6. Taxonomy of the Late Devonian placoderm remains from the Holy Cross Mountains, Poland, described by Gorizdro-Kulczycka (L934,1950) and Kulczycki (1956, 1957),is revised. Several recently found specimens are also mentioned. The old collections are composed of representatives of Ptyctodontidae, Holonematidae, Plourdosteidae, Pholi- dosteidae, Selenosteidae, Titanichthyidae and Dinichthyidae, the latter with an unde- scribed species of Eastmanosteus. Newly found specimens belong to Ptyctodontidae, Plourdosteidae and Dinichthyidae. The occurrence of the Antiarcha in the Late Devonian of the Holy Cross Mountains, suggestedby former authors, has not been confirmed. K e y w o rd s : Placodermi,Late Devonian, Holy Cross Mountains, Poland. Alexander Ivanov [[email protected]], Laboratory of Paleontology, Institute of the Earth Crust, Sankt-Petersburg University, 16 Liniya 29, 199178 St.Petersburg, Russia. Michał Ginter [email protected]], InsĘtut Geologii Podstawowej, Uniwersytet War szaw ski, ul. Zw irki i Wi gury 9 3, 02 -089 War szaw a, P oland. Introduction The main goals of this study are to revise placodermsfrom the Late Devonian of the Holy Cross Mountains collected by Jan Czarnocki, Julian Kulczycki and Zinuda Gorizdro-Kulczycka in the first half of the century (the material now housed in the Museum of the Polish Geological Instituteand in the Museum of the Earth in Warsaw), and to describe a fęw new specimenscollected recently by Jerzy Dzik and Grzegorz Racki. -
A New Lower Devonian Arthrodire (Placodermi) from the NW Siberian Platform
Estonian Journal of Earth Sciences, 2013, 62, 3, 131–138 doi: 10.3176/earth.2013.11 A new Lower Devonian arthrodire (Placodermi) from the NW Siberian Platform Elga Mark-Kurik Institute of Geology at Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; [email protected] Received 24 August 2012, accepted 5 November 2012 Abstract. A new genus and species of arthrodires, Eukaia elongata (Actinolepidoidei, Placodermi), is described from the Lower Devonian, ?Pragian of the Turukhansk region, NW Siberian Platform. A single specimen of the fish, a skull roof, comes probably from the lower part of the Razvedochnyj Formation. The occurrence of an actinolepidoid arthrodire in the Early Devonian of this area of Siberia is unexpected. Eukaia shows some distant relationship with the genus Actinolepis, but several features indicate similarity to representatives of other arthrodires. Key words: actinolepidoid arthrodire, placoderm, Lower Devonian, ?Pragian, NW Siberian Platform. INTRODUCTION (Fig. 1). The first two units are Lochkovian in age, the lower part of the Razvedochnyj Fm belongs to the Pragian The northwestern part of the Siberian Platform in the and the upper part of the Razvedochnyj Fm plus the lower Russian Arctic is well known for rich and amphiaspidid- part of the Mantura Fm to the Emsian (Matukhin 1995). dominated Early Devonian fish faunas. One of the The Zub Fm (up to 150 m thick) consists of carbonaceous- important areas where these faunas have been discovered argillaceous and sulphate rocks. Invertebrates and fossil is the near-Yenisej zone of the Tunguska syneclise fishes, e.g. a cyathaspidid Steinaspis, are comparatively (Krylova et al. -
Devonian Fish Remains from the Munabia Sandstone, Carnarvon Basin, Western Australia
------ ---_ - _- Ree. West. /lust. Mus. 1991,15(3) 501515 Devonian fish remains from the Munabia Sandstone, Carnarvon Basin, Western Australia John A. Long· Abstract Fish fossils have been recovered from two horizons at the base ofthe Munabia Sandstone, near the type section of Williambury Station. The fauna contains the antiarch Bothriolepis sp" the arthrodire Holonema sp., and an indeterminate osteolepidid crossopterygian. The presence of Holonema (Eifelian-Frasnian) with Bothriolepis(Givetian-Famennian), as well as microfossil dates from the underlying conformable Gneudna Formation (Early Frasnian), suggests a Frasnian age for the base of the Munabia Sandstone. Conodonts suggest that the top of the Munabia Sandstone is of Lower Famennian age. Introduction The Munabia Sandstone outcrops over a distance ofalmost 90 km from Mt. Sandiman homestead in the south to just north of Williambury Station as part of a linear belt of Devonian rocks at the base of the Carnarvon Basin sedimentary succession (Figure 1). The type section occurs about 8 km southeast of Williambury Station where it conformably overlies the lower Frasnian carbonates of the Gneudna Formation and underlies the coarser conglomerates of the Willaradie Formation (Condon 1954, 1965, Hocking et al. 1987). Although Condon (1965) favoured a marine depositional environment for the Munabia Sandstone and Willaradie Formation, Moors (1981) reported that only the base of the Munabia Sandstone was marine, the majority of the sequence representing distal fan to braided stream deposits, with minor marine incursions. The overlying Willaradie Formation is part of this depositional event, representing proximal alluvial fan deposits. None of the previous field studies of the Munabia Sandstone had found any body fossils, although trace fossils are common in the lower (marine) horizons, and the age of the unit was based entirely on extrapolation from the underlying Gneudna Formation, itself well-dated from marine invertebrates and palynomorphs (Seddon 1969, Dring 1980, Playford and Dring 1981). -
The Ohio Academy of Science 116Th Annual Meeting Hosted by Cuyahoga Community College Eastern Campus
A-2. The Ohio Journal of Science Vol. 107 (1) The Ohio Academy of Science GENERAL SCHEDULE 116th Annual Meeting Hosted by Friday, April 20, 2007 Cuyahoga Community College Eastern Campus April 21-22, 2007 3:00 PM-5:00 PM The Ohio Academy of Science Board of Trustees Meeting About the Annual Meeting ELA Room 229 The Ohio Academy of Science’s Annual Meeting is for academic, governmental, and industry scientists and engineers, university and pre- Saturday, April 21, 2007 college educators and teachers, and pre-college, undergraduate, and graduate students, and interested lay citizens in the Ohio region. 7:30 AM-11:30 AM General Meeting Registration ELA Lobby Welcome! Cuyahoga Community College Eastern Campus welcomes you to the 9:00 AM-11:00 AM Pathways to Your Future Symposium 116th Annual Meeting of The Ohio Academy of Science. We invite ELA Room 122 you to explore our campus and to share in the excitement and opportunities provided in this program. 9:00 AM-11:30 AM Morning Podium Sessions in ELA REGISTRATION: Registration is required for all meeting presenters and attendees. On-site registration will be available at a higher rate. The Morning Poster Sessions in Ohio Academy of Science must receive forms by April 9, 2007. Please ELA Commons use Registration Form on the last page. Mail completed form and fee to: 11:30 AM Official Notice of Annual OAS Annual Meeting Registration Business Meeting The Ohio Academy of Science for Academy Members Only. PO Box 12519 ELA Room 122 Columbus OH 43212-0519 FAX 614/488-7629 (for Credit Card or PO only) 11:30 AM Lunch on your own Available at nearby restaurants. -
Family-Group Names of Fossil Fishes
European Journal of Taxonomy 466: 1–167 ISSN 2118-9773 https://doi.org/10.5852/ejt.2018.466 www.europeanjournaloftaxonomy.eu 2018 · Van der Laan R. This work is licensed under a Creative Commons Attribution 3.0 License. Monograph urn:lsid:zoobank.org:pub:1F74D019-D13C-426F-835A-24A9A1126C55 Family-group names of fossil fishes Richard VAN DER LAAN Grasmeent 80, 1357JJ Almere, The Netherlands. Email: [email protected] urn:lsid:zoobank.org:author:55EA63EE-63FD-49E6-A216-A6D2BEB91B82 Abstract. The family-group names of animals (superfamily, family, subfamily, supertribe, tribe and subtribe) are regulated by the International Code of Zoological Nomenclature. Particularly, the family names are very important, because they are among the most widely used of all technical animal names. A uniform name and spelling are essential for the location of information. To facilitate this, a list of family- group names for fossil fishes has been compiled. I use the concept ‘Fishes’ in the usual sense, i.e., starting with the Agnatha up to the †Osteolepidiformes. All the family-group names proposed for fossil fishes found to date are listed, together with their author(s) and year of publication. The main goal of the list is to contribute to the usage of the correct family-group names for fossil fishes with a uniform spelling and to list the author(s) and date of those names. No valid family-group name description could be located for the following family-group names currently in usage: †Brindabellaspidae, †Diabolepididae, †Dorsetichthyidae, †Erichalcidae, †Holodipteridae, †Kentuckiidae, †Lepidaspididae, †Loganelliidae and †Pituriaspididae. Keywords. Nomenclature, ICZN, Vertebrata, Agnatha, Gnathostomata. -
Fossil Fishes (Arthrodira and Acanthodida) from the Upper Devonian Chadakoin Formation of Erie County, Pennsylvania1
Fossil Fishes (Arthrodira and Acanthodida) from the Upper Devonian Chadakoin Formation of Erie County, Pennsylvania1 KEVIN M. YEAGER2, Department of Geosciences, Edinboro University of Pennsylvania, Edinboro, PA 16444 ABSTRACT. Several fossil fish were discovered in 1994 in the Upper Devonian Chadakoin Formation, near Howard Falls, just outside of Edinboro, Erie County, Pennsylvania. These fossils are fragmentary in nature and have been described based on their morphology. They are identified as the median dorsal plate of the large arthrodire Dunkleosteus terrelli Newberry, 1873, and the spines of probable acanthodian fishes. The identification of the median dorsal plate of Dunkleosteus represents a new occurrence of the genus. In general, these discoveries are of scientific interest because very little is known about the composition of the fish fauna that inhabited the Devonian shallow seas of northwestern Pennsylvania. OHIO J. SCI. 96 (3): 52-56,1996 INTRODUCTION Pennsylvania were deposited in a shallow water en- This study was an outgrowth of geologic field map- vironment. The shallower bottom sediments were oxy- ping being conducted in the Howard Falls area near genated by waves and currents, and supported a variety Edinboro, Pennsylvania. In August 1994, the first of of scavengers. several vertebrate fossil specimens were discovered. The Nonetheless, reduced preservation potential alone first specimen was excavated, reconstructed, and identi- does not explain why fossil fishes are poorly known fied by specialists from the Pennsylvania State Museum, from Pennsylvania. The Devonian rocks of southern Harrisburg. Since that time, four more vertebrate speci- New York were deposited in shallow waters also, but mens have been collected. These specimens were have yielded a diverse fish fauna (Eastman 1907). -
Comments on Distribution and Taphonomy of Devonian Placoderms in the Holy Cross Mountains, Poland
Comments on distribution and taphonomy of Devonian placoderms in the Holy Cross Mountains, Poland Piotr Szrek Taphonomy, stratigraphical occurrences and geographical distribution of Devonian placoderms in the Holy Cross Mountains described by former researchers is revised. Four main types of preservation states occur in the placoderm fossils of that region. Fossil preservation depends on geodynamic processes. Mechanical damage appears to be the main factor explaining the final state of preservation. For most of the previously described as well as the new specimens, the occurrences were dated biostratigraphically by palynomorphs and conodonts. The taxonomic distribution of placoderms in space and time within the Devonian strata in the Holy Cross Mountains correlates well with the Devonian nekton revolution, but it is also controlled by the regional palaeoecology and local synsedimentary tectonics of the carbonate platform. • Key words: Placodermi, Devonian, distribution, taphonomy, Holy Cross Mountains, Poland. SZREK, P. 2020. Comments on distribution and taphonomy of Devonian placoderms in the Holy Cross Mountains, Poland. Bulletin of Geosciences 95(1), 23–39 (7 figures, 2 tables). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received June 4, 2019; accepted in revised form December 16, 2019; published online January 21, 2020; issued March 31, 2020. Piotr Szrek, Polish Geological Institute–National Research Institute, 4 Rakowiecka Street, 00-975 Warsaw, Poland; piotr. [email protected] & University of Warsaw, Faculty of Geology, Żwirki i Wigury Street 93, 02-089 Warsaw, Poland Placodermi McCoy, 1848 (armoured fishes) are a group areas. However, Kulczycki worked prior to the publication of early jawed vertebrates that appeared in the Silurian of Wegener’s theory of continental drift, resulting in some period and reached maximum diversification during the erroneous palaeogeographic conclusions, but his cor- Devonian. -
The Gogo Fossil Sites (Late Devonian, Western Australia) As a Case Study
Memoirs of Museum Victoria 74: 5–15 (2016) Published 2016 ISSN 1447-2546 (Print) 1447-2554 (On-line) http://museumvictoria.com.au/about/books-and-journals/journals/memoirs-of-museum-victoria/ Quantifying scientific significance of a fossil site: the Gogo Fossil sites (Late Devonian, Western Australia) as a case study JOHN A. LONG School of Biological Sciences, Flinders University, GPO Box 2100 Adelaide, South Australia 50901 and Geosciences, Museum Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia ([email protected]) Abstract Long, J.A. 2016. Quantifying scientific significance of a fossil site: the Gogo Fossil sites (Late Devonian, Western Australia) as a case study. Memoirs of Museum Victoria 74: 5–15. Assessing the scientific significance of fossil sites has up to now been largely a matter of subjective opinion with few or no metrics being employed. By applying similar metrics used for assessing academic performance, both qualitative and quantitative, to fossil sites we gain a real indication of their significance that enables direct comparison with other sites both nationally and globally. Indices suggested are those using total pages published for both peer-reviewed and combined peer-reviewed and popular publications, total citations from the papers, total impact points for site (citing palaeontology- related papers only), total number of very high impact papers (VHIP; journal impact factor>30) and social media metrics. These provide a measure of how much the published fossil data from a site has been utilised. The Late Devonian fossils of the Gogo Formation of Western Australia are here used as an example of how these metrics can be applied. -
Large Upper Devonian Arthrodires from Iran
LIBRARY OF THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN 550.5 FI *.2l-25 GEOLOGY UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN GEOLOGY A^^o-Oo OAy ^FIELDIANA Geology Published by Field Museum of Natural History Volume 23, No. 5 November 30, 1973 Large Upper Devonian Arthrodires from Iran Hans-Peter Schultze Universitatsdozent, Geol.-Palaont. Institut, Universitat Gottingen ABSTRACT From the Upper Devonian of East Iran, fossil remains of three genera of brachythoracid arthrodires are described: Eastmanosteus sp., Holonema rugosum (Claypole), and Aspidichthys ingens (Koenen). This occurrence extends the range of distribution of the three genera, but like all others known is situated within the "tropics" of the Devonian. In Eastmanosteus, the levator capitis muscle attaches on both sides of the posteromedian cusp of the nuchal plate. The double sockets on the ventral surface of the nuchal plate run upward and backward so that they are interpreted as grooves for the craniospinal process of the neural endocranium in accordance with Stetson (1930). On the posterior dorsolateral plate of Aspi- dichthys the main lateral line canal turns postero-ventrally and no canal passes onto the median dorsal plate. From Iran, Devonian fish remains were recorded first by Rieben (1935) from SSE of Zonuz, Azerbeidjan (p. 82: "Holoptychius cf. flemingi AG., Bothriolepis and Dinichthys" : The remains are a scale of Holoptychius sp.; a dendrodont tooth belonging to a genus of the Holoptychiidae having osteodentine with a canal system like that of Laccognathus in the pulp cavity; a piece bearing an imprint of a plate from a bothriolepid and other fragments of arthrodiran plates; and a fragment of a plate from a brachythoracid smaller than the of the .