DOCSLIB.ORG

Noqvtates PUBLISHED by the AMERICAN MUSEUM of NATURAL HISTORY CENTRAL PARK WEST at 79TH STREET, NEW YORK, N.Y

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Noqvtates PUBLISHED by the AMERICAN MUSEUM of NATURAL HISTORY CENTRAL PARK WEST at 79TH STREET, NEW YORK, N.Y AMERICAN MUSEUM Noqvtates PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, N.Y. 10024 Number 2828, pp. 1-24, figs. 1-11 October 21, 1985 Stethacanthid Elasmobranch Remains from the Bear Gulch Limestone (Namurian E2b) of Montana RICHARD LUND' ABSTRACT Four chondrichthyan species assigned to the atoquadrate and mandible, numbers oftooth fam- cladodontid genus Stethacanthus are described ilies and pectoral prearticular basals, morphology from the Bear Gulch Limestone ofMontana. Spec- ofthe pelvic girdle and areas ofsquamation. Com- imens are referred to Stethacanthus cf. S. alto- parison with other Bear Gulch stethacanthids nensis and S. cf. S. productus. Two other species strongly suggests that the presence of specialized are too immature to assign with certainty to known cranial and first dorsal fin squamation, with the stethacanthid spine species. The histology and presence of the first dorsal fin and spine, are sec- morphology ofthree isolated cladodont tooth types ondary sexual characters ofmature males. Clado- is described, one of which is referred to Cladodus selache is indicated as the sister group of the Ste- robustus. The species of Stethacanthidae are dis- thacanthidae, with the "Symmoriidae" being the tinguishable on the shapes and proportions ofpal- sister group of Stethacanthus altonensis. INTRODUCTION The Upper Mississippian marine Bear taxa have also provided excellent data on the Gulch limestone member of the Heath For- relative values of the spines and other mor- mation has yielded approximately seven phologicalparameters forgrossdiagnostic dif- species ofcladodont elasmobranchs referable ferentiation, and have particularly demon- to the family Stethacanthidae (Lund, 1974). strated that striking sexual dimorphism within Several ofthese have been found in sufficient the family may pose insurmountable diffi- abundance or completeness to allow ade- culties in the recognition and diagnosis of quate holomorphic diagnosis and description incomplete or inadequately represented (Lund, 1974, 1984, 1985, in press). These forms. Causing particular difficulty are the ' Professor, Biology Department, Adelphi University, Garden City, N.Y. 11530; Research Associate, Department of Ichthyology, American Museum of Natural History. Copyright K American Museum of Natural History 1985 ISSN 0003-0082 / Price $2.25 2 AMERICAN MUSEUM NOVITATES NO. 2828 observations that only males may possess the The specimen CM 23654 was originally characteristic first dorsal spines and fins, and referred to as a female S. altonensis (Lund, only at sexual maturity (Lund, 1984; Fal- 1974). The spine ofthe specimen is immature catus falcatus, Lund, 1985; probably and therefore proximally incomplete. The Stethacanthus altonensis, Lund, 1974 and apical angle ofthe spine is approximately 240 below; S. cf. S. productus, below). In one oth- and the structure of the spine suggests that er, "Physonemus" attenuatus (Lund, in press) the apex was a posterodorsal continuation of there is considerable change of form of the the base (fig. 2D). The apical angle of the first dorsal spine and braincase with growth, spine of S. altonensis is 340 and the apex but females are not known for this species. projects dorsally in relation to the base (New- Additionally, marked differences occur in the berry, 1889, 1897; Lund, 1974). No traces of abundances of males versus females in all dorsal fin elements are preserved. groups with striking sexual dimorphism In dorsal view, the neurocranium is pro- (Ghiselin, 1974; also see Lund, 1982). Fur- portioned essentially as in S. altonensis, but ther, sexually dimorphic living elasmo- with broader supraorbital crests. The pala- branchs ofdifferent sexes may occupy differ- toquadrate has grooves for 6-8 tooth fami- ent ranges at different times (Branstetter, lies, as in S. altonensis, but the palatine por- 1981), suggesting that there may be difficul- tion is dorsally concave and the postorbital ties in locating or recognizing fossil chon- expansion is rounded posterodorsally. There drichthyans ofthe sex opposite to that of the is no visible extension of the palatoquadrate type specimen. Following from this infor- anterior to the mesially inturned ethmoid mation, the purported absence of claspers in process. A quadrate shelf is absent, and the Cladoselache, for instance, may more rea- quadrate condyle extends below the level of sonably be attributed to either an absence of the tooth row. Meckel's cartilage is unknown, mature males at the localities searched or an but clearly had relatively few tooth families inability to recognize males than to the re- and an anteriorly placed coronoid process. mote possibility that this rather specialized The hyomandibula is stout and held in close chondrichthyan lacked claspers (Harris, 1938, association with the palatoquadrate, partic- 1951; Zangerl, 1981; Rosen et al., 1981). ularly near the quadrate condyle (fig. 1). This report will describe Bear Gulch shark "Stemmatodus"-type branchial denticles are specimens that are too rare or too incomplete evident. to assign with certainty to a previously named The pectoral fin is supported by 12 or 13 species, but that are critical to understanding prearticular basals, and eight radials are sup- the morphological differences between species ported on the metapterygial plate. The me- within the Bear Gulch Stethacanthidae. tapterygial axis is poorly preserved. The pel- ABBREVIATIONS: Specimens have been de- vic girdles are triangular, with six conspicuous posited either with the Section of Vertebrate diazonal foramina, and a very small metap- Fossils, Carnegie Museum of Natural His- terygial plate. Each girdle supports at least 12 tory, Pittsburgh, Pa. (CM), or with the Geo- single-jointed radials. Clasper elements are logic Museum ofthe University ofMontana, unknown. Missoula, Montana (MV). The second dorsal fin consists of a mini- mum of 19 separate but closely spaced, one- DESCRIPTIONS jointed radials, the distal segments of which are quite elongate. The posterior portion of Stethacanthus cf. S. productus the fin is followed by a thin triangular plate, Newberry, 1897 but it cannot be determined whether this plate Figures 1, 2, 7F supported fin radials as in Falcatus falcatus PREvIous REFERENCES: Stethacanthus al- (Lund, 1985). The caudal fin, as illustrated tonensis Lund, 1974, fig. 10, CM 23654. in Lund (1974), is heterocercal, and of rela- Stethacanthus cf. S. productus Lund, 1984. tively high angle, with separate neural arches REFERRED SPECIMENS: CM 23654, whole, and spines and discrete dorsal and ventral immature, disturbed specimen; CM 35695, lobes. Precaudal neural arches are paired, long palatoquadrate; CM 37669, palatoquadrate; and thin, and lack median neural spines. MV 6160, pectoral and pelvic girdles. Squamation is unknown, although loose 1985 LUND: STETHACANTHID REMAINS 3 denticles are present in MV 6160. Although no specimen is complete, and therefore no accurate length measurements can be made, the length ofCM 23654 approaches 1 m, and the palatoquadrate is 11.6 cm in length. The palatoquadrate CM 37669 is 24.5 cm long, suggesting a total length of around 2 m for an intact individual. S. cf. S. productus is thus significantly larger than S. altonensis, and the largest known vertebrate in the Bear Gulch Limestone. This size differential is re- flected in the sizes ofknown spines ofthe two species (Newberry, 1889, 1897). Stethacanthus cf. S. productus differs from S. altonensis in the shape of the pterygoid portion of the palatoquadrate, the higher number of prearticular basals of the pectoral fin, the morphology of the pelvic girdle and fin, and in the relative length of the radials ofthe second dorsal fin, as well as in the shape LI and size of the first dorsal fin spine. The two FIG. 1. Stethacanthus cf. S. productus New- species are significantly similar, however, in berry, 1897. CM 23654. Neurocranium, palato- braincase shape, general plan of the pectoral quadrate, and hyomandibular, mesial view. Scale fin, and particularly in lacking a large metap- in cm; hyo, hyomandibular; sn, spiracular notch. terygial plate of the pelvic fin. The imma- turity ofthe first dorsal fin spine ofCM 23654, a moderately large specimen, is striking, sug- The contents of the digestive tract consist gesting that as in Falcatus falcatus (Lund, of an entire, although fragmented, conodon- 1985) the first dorsal fin spine is a secondary tochordate (Melton and Scott, 1973; Scott, sexual character present only in mature 1973). (probably male) individuals. The neurocranium has broad supraorbital crests and a very strong postorbital arcade. Stethacanthus cf. S. The otic region is broad and flat ventrally, altonensis narrower and rounded dorsally, with prom- Figures 3 and 4 inent ridges for anterior and posterior vertical REFERRED SPECIMEN: CM 37680. semicircular canals. Serial supraorbital fo- This specimen consists of jaws, eye pig- ramina for Ramus Ophthalmicus Superfici- ments, branchial and pectoral skeleton, ver- alis fibers supplying the supraorbital lateral- tebral axis with 54 segments, dislocated line canals are present dorsally, and a median braincase, and digestive tract contents. Cal- basal foramen, probably for the hypophysis cification ofthe neurocranium ofthe 10.8 cm and internal carotid arteries (Jarvik, 1977), fossil is incomplete anteriorly. The specimen is present midventrally. is referred to S. altonensis on the basis ofthe The mandible has a high coronoid process following: palatoquadrate has
Load more

Recommended publications
  • Symmoriiform Sharks from the Pennsylvanian of Nebraska
    Acta Geologica Polonica, Vol. 68 (2018), No. 3, pp. 391–401 DOI: 10.1515/agp-2018-0009 Symmoriiform sharks from the Pennsylvanian of Nebraska MICHAŁ GINTER University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, PL-02-089 Warsaw, Poland. E-mail: [email protected] ABSTRACT: Ginter, M. 2018. Symmoriiform sharks from the Pennsylvanian of Nebraska. Acta Geologica Polonica, 68 (3), 391–401. Warszawa. The Indian Cave Sandstone (Upper Pennsylvanian, Gzhelian) from the area of Peru, Nebraska, USA, has yielded numerous isolated chondrichthyan remains and among them teeth and dermal denticles of the Symmoriiformes Zangerl, 1981. Two tooth-based taxa were identified: a falcatid Denaea saltsmani Ginter and Hansen, 2010, and a new species of Stethacanthus Newberry, 1889, S. concavus sp. nov. In addition, there occur a few long, monocuspid tooth-like denticles, similar to those observed in Cobelodus Zangerl, 1973, probably represent- ing the head cover or the spine-brush complex. A review of the available information on the fossil record of Symmoriiformes has revealed that the group existed from the Late Devonian (Famennian) till the end of the Middle Permian (Capitanian). Key words: Symmoriiformes; Microfossils; Carboniferous; Indian Cave Sandstone; USA Midcontinent. INTRODUCTION size and shape is concerned [compare the thick me- dian cusp, almost a centimetre long, in Stethacanthus The Symmoriiformes (Symmoriida sensu Zan- neilsoni (Traquair, 1898), and the minute, 0.5 mm gerl 1981) are a group of Palaeozoic cladodont sharks wide, multicuspid, comb-like tooth of Denaea wangi sharing several common characters: relatively short Wang, Jin and Wang, 2004; Ginter et al. 2010, figs skulls, large eyes, terminal mouth, epicercal but ex- 58A–C and 61, respectively].
    [Show full text]
  • Sharks from the Middle-Late Devonian Aztec Siltstone, Southern Victoria Land, Antarctica
    Records of the Western Australian Museum 17: 287-308 (1995). Sharks from the Middle-Late Devonian Aztec Siltstone, southern Victoria Land, Antarctica John A. Longl and Gavin C. Young2 I Western Australian Museum, Francis Street, Perth, Western Australia 6000 2 Australian Geological Survey Organisation, p.a. Box 378, Canberra, A.C.T. 2601 Abstract Shark teeth representing three new taxa are described from the Middle-Late Devonian Aztec Siltstone of southern Victoria Land, Antarctica. Portalodus bradshawae gen. et sp. novo is represented by large diplodont teeth which have a base with a well-produced labial platform. It occurs in the middle to upper sections of the Aztec Siltstone. Aztecodus harmsenae gen. et sp. novo is represented by broad bicuspid teeth, wider than high, with numerous medial crenulations and twin nutritive foramina penetrating the rectangular base. It occurs in the middle sections of the Aztec Siltstone. The teeth of Anareodus statei gen. et sp. novo are characterised by having a main cusp which is more than twice as high as the second cusp, a small cusplet developed on the outer cutting edge of the main cusp, sometimes with few crenulations developed in the middle of the two cusps, and the base is strongly concave. Antarctilanma cf. prisca Young, 1982 is also recorded from the middle and upper sections of the Aztec Siltstone above the thelodont horizons and occurring with phyllolepids and Pambulaspis in the Cook Mountains section south of Mt Hughes. The chondrichthyan fauna from the Aztec Siltstone now contains at least 5 species, being the most diverse assemblage of Middle Devonian chondrichthyans (based on teeth) from one stratigraphic unit.
    [Show full text]
  • Investigating Sexual Dimorphism in Ceratopsid Horncores
    University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2013-01-25 Investigating Sexual Dimorphism in Ceratopsid Horncores Borkovic, Benjamin Borkovic, B. (2013). Investigating Sexual Dimorphism in Ceratopsid Horncores (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26635 http://hdl.handle.net/11023/498 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Investigating Sexual Dimorphism in Ceratopsid Horncores by Benjamin Borkovic A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF BIOLOGICAL SCIENCES CALGARY, ALBERTA JANUARY, 2013 © Benjamin Borkovic 2013 Abstract Evidence for sexual dimorphism was investigated in the horncores of two ceratopsid dinosaurs, Triceratops and Centrosaurus apertus. A review of studies of sexual dimorphism in the vertebrate fossil record revealed methods that were selected for use in ceratopsids. Mountain goats, bison, and pronghorn were selected as exemplar taxa for a proof of principle study that tested the selected methods, and informed and guided the investigation of sexual dimorphism in dinosaurs. Skulls of these exemplar taxa were measured in museum collections, and methods of analysing morphological variation were tested for their ability to demonstrate sexual dimorphism in their horns and horncores.
    [Show full text]
  • A New Euselachian Shark from the Early Permian of the Middle Urals, Russia
    A new euselachian shark from the early Permian of the Middle Urals, Russia ALEXANDER O. IVANOV, CHRISTOPHER J. DUFFIN, and SERGE V. NAUGOLNYKH Ivanov , A.O., Duffin, C.J., and Naugolnykh, S.V. 2017. A new euselachian shark from the early Permian of the Middle Urals, Russia. Acta Palaeontologica Polonica 62 (2): 289–298. The isolated teeth of a new euselachian shark Artiodus prominens Ivanov and Duffin gen. et sp. nov. have been found in the Artinskian Stage (Early Permian) of Krasnoufimskie Klyuchiki quarry (Sverdlovsk Region, Middle Urals, Russia). The teeth of Artiodus possess a multicuspid orthodont crown with from four to nine triangular cusps; prominent labial projection terminating in a large round tubercle; distinct ornamentation from straight or recurved cristae; oval or semilu- nar, elongate, considerably vascularized base; dense vascular network formed of transverse horizontal, ascending, short secondary and semicircular canals. The teeth of the new taxon otherwise most closely resemble the teeth of some prot- acrodontid and sphenacanthid euselachians possessing a protacrodont-type crown, but differ from the teeth of all other known euselachians in the unique structure of the labial projection. The studied teeth vary in crown and base morphol- ogy, and three tooth morphotypes can be distinguished in the collection reflecting a moderate degree of linear gradient monognathic heterodonty. The range of morphologies otherwise displayed by the collection of teeth shows the greatest similarity to that described for the dentitions of relatively high-crowned hybodontids from the Mesozoic. The internal structure of the teeth, including their vascularization system is reconstructed using microtomography. The highest chon- drichthyan taxonomic diversity is found in the Artinskian, especially from the localities of the Middle and South Urals.
    [Show full text]
  • Chondrichthyan Fauna of the Frasnian–Famennian Boundary Beds in Poland
    Chondrichthyan fauna of the Frasnian–Famennian boundary beds in Poland MICHAŁ GINTER Michał Ginter. 2002. Chondrichthyan fauna of the Frasnian–Famennian boundary beds in Poland. Acta Palaeontologica Polonica 47 (2): 329–338. New chondrichthyan microremains from several Frasnian–Famennian sections in the Holy Cross Mountains and Dębnik area (Southern Poland) are investigated and compared to previous data. The reaction of different groups of chondrichthyans to environmental changes during the Kellwasser Event is analysed. Following the extinction of phoebodont sharks of Phoebodus bifurcatus group before the end of the Frasnian, only two chondrichthyan species, viz. Protacrodus vetustus Jaekel, 1921 and Stethacanthus resistens sp. nov. (possibly closely related to “Cladodus” wildungensis Jaekel, 1921), occur in the upper part of Frasnian Palmatolepis linguiformis conodont Zone and persist into the Famennian. Global cooling is considered a possible cause of the extinction of Frasnian subtropical phoe− bodonts on Laurussian margins. Key words: Chondrichthyes, Kellwasser Event, Devonian, Poland. Michał Ginter [[email protected]], Instytut Geologii Podstawowej, Uniwersytet Warszawski, Żwirki i Wigury 93, PL−02−089 Warszawa, Poland. Introduction Characteristics of the localities Chondrichthyan faunas of the late Palmatolepis linguiformis Three sections spanning the Frasnian–Famennian boundary and the Palmatolepis triangularis conodont zones on south− were sampled bed by bed (for location of most samples, see ern Laurussian margins substantially differ from those of the Racka 2000): the middle wall of the Kowala–Wola Quarry in rest of the Frasnian and Famennian. The main difference is the south−western Holy Cross Mts, south of Kielce; an artficial the absence of Phoebodus, a typical Mid− to Late Devonian trench on the eastern bank of Łagowica River, between the vil− pelagic, shelf dwelling shark (Ginter and Ivanov 1992).
    [Show full text]
  • Xenacanthus (Chondrichthyes: Xenacanthiformes) from North America
    Acta Geologica Polonica, Vol. 49 (J 999), No.3, pp. 215-266 406 IU S UNES 0 I Dentitions of Late Palaeozoic Orthacanthus species and new species of ?Xenacanthus (Chondrichthyes: Xenacanthiformes) from North America GARY D. JOHNSON Department of Earth Sciences and Physics, University of South Dakota; 414 East Clark Street, Vermillion, SD 57069-2390, USA. E-mail: [email protected] ABSTRACT: JOHNSON, G.D. 1999. Dentitions of Late Palaeozoic Orthacanthus species and new species of ?Xenacanthus (Chondrichthyes: Xenacanthiformes) from North America. Acta Geologica Polonica, 49 (3),215-266. Warszawa. Orthacanthus lateral teeth have paired, variably divergent, smooth, usually carinated labio-lingually compressed principal cusps separated by a central foramen; one or more intermediate cusps; and an api­ cal button on the base isolated from the cusps. Several thousand isolated teeth from Texas Artinskian bulk samples are used to define the heterodont dentitions of O. texensis and O. platypternus. The O. tex­ ensis tooth base has a labio-Iingual width greater than the anteromedial-posterolateral length, the basal tubercle is restricted to the thick labial margin, the principal cusps are serrated to varying degrees, and the posterior cusp is larger. The O. platypternus tooth base is longer than wide, its basal tubercle extends to the center, the labial margin is thin, serrations are absent on the principal cusps, the anterior cusp is larger, and a single intermediate cusp is present. More than two hundred isolated teeth from Nebraska (Gzhelian) and Pennsylvania (Asselian) provide a preliminary description of the heterodont dentition of O. compress us . The principal cusps are similar to O.
    [Show full text]
  • The Pharynx of the Stem-Chondrichthyan Ptomacanthus and the Early Evolution of the Gnathostome Gill Skeleton
    ARTICLE https://doi.org/10.1038/s41467-019-10032-3 OPEN The pharynx of the stem-chondrichthyan Ptomacanthus and the early evolution of the gnathostome gill skeleton Richard P. Dearden 1, Christopher Stockey1,2 & Martin D. Brazeau1,3 The gill apparatus of gnathostomes (jawed vertebrates) is fundamental to feeding and ventilation and a focal point of classic hypotheses on the origin of jaws and paired appen- 1234567890():,; dages. The gill skeletons of chondrichthyans (sharks, batoids, chimaeras) have often been assumed to reflect ancestral states. However, only a handful of early chondrichthyan gill skeletons are known and palaeontological work is increasingly challenging other pre- supposed shark-like aspects of ancestral gnathostomes. Here we use computed tomography scanning to image the three-dimensionally preserved branchial apparatus in Ptomacanthus,a 415 million year old stem-chondrichthyan. Ptomacanthus had an osteichthyan-like compact pharynx with a bony operculum helping constrain the origin of an elongate elasmobranch-like pharynx to the chondrichthyan stem-group, rather than it representing an ancestral condition of the crown-group. A mixture of chondrichthyan-like and plesiomorphic pharyngeal pat- terning in Ptomacanthus challenges the idea that the ancestral gnathostome pharynx con- formed to a morphologically complete ancestral type. 1 Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot SL5 7PY, UK. 2 Centre for Palaeobiology Research, School of Geography, Geology and the Environment, University of Leicester, University Road, Leicester LE1 7RH, UK. 3 Department of Earth Sciences, Natural History Museum, London SW7 5BD, UK. Correspondence and requests for materials should be addressed to M.D.B.
    [Show full text]
  • Late Devonian and Early Carboniferous Chondrichthyans from the Fairfield Group, Canning Basin, Western Australia
    Palaeontologia Electronica palaeo-electronica.org Late Devonian and Early Carboniferous chondrichthyans from the Fairfield Group, Canning Basin, Western Australia Brett Roelofs, Milo Barham, Arthur J. Mory, and Kate Trinajstic ABSTRACT Teeth from 18 shark taxa are described from Upper Devonian to Lower Carbonif- erous strata of the Lennard Shelf, Canning Basin, Western Australia. Spot samples from shoal facies in the upper Famennian Gumhole Formation and shallow water car- bonate platform facies in the Tournaisian Laurel Formation yielded a chondrichthyan fauna including several known species, in particular Thrinacodus ferox, Cladodus thomasi, Protacrodus aequalis and Deihim mansureae. In addition, protacrodont teeth were recovered that resemble formally described, yet unnamed, teeth from Tournaisian deposits in North Gondwanan terranes. The close faunal relationships previously seen for Late Devonian chondrichthyan taxa in the Canning Basin and the margins of north- ern Gondwana are shown here to continue into the Carboniferous. However, a reduc- tion in species overlap for Tournaisian shallow water microvertebrate faunas between the Canning Basin and South China is evident, which supports previous studies docu- menting a separation of faunal and terrestrial plant communities between these regions by this time. The chondrichthyan fauna described herein is dominated by crushing type teeth similar to the shallow water chondrichthyan biofacies established for the Famennian and suggests some of these biofacies also extended into the Early Carboniferous. Brett Roelofs. Department of Applied Geology, Curtin University, GPO Box U1987 Perth, WA 6845, Australia. [email protected] Milo Barham. Department of Applied Geology, Curtin University, GPO Box U1987 Perth, WA 6845, Australia. [email protected] Arthur J.
    [Show full text]
  • A Classic Late Frasnian Chondrichthyan Assemblage from Southern Belgium
    Acta Geologica Polonica, Vol. 67 (2017), No. 3, pp. 381–392 DOI: 10.1515/agp-2017-0017 A classic Late Frasnian chondrichthyan assemblage from southern Belgium 1 2 3 MICHAŁ GINTER , SOFIE GOUWY and STIJN GOOLAERTS 1 Faculty of Geology, University of Warsaw, Żwirki i Wigury 93, 02-089 Warsaw, Poland. E-mail: [email protected] 2 Paleontology Section, Geological Survey of Canada, 3303, 33str NW Calgary, T2L 2A7, Canada E-mail: [email protected] 3 Royal Belgian Institute of Natural Sciences, Vautierstraat 29, B-1000 Brussels, Belgium E-mail: [email protected] ABSTRACT: Ginter, M., Gouwy, S. and Goolaerts, S. 2017. A classic Late Frasnian chondrichthyan assemblage from southern Belgium. Acta Geologica Polonica, 67 (3), 381–392. Warszawa. Samples from the Upper Frasnian (Devonian) of Lompret Quarry and Nismes railway section in Dinant Synclinorium, southern Belgium, yielded several chondrichthyan teeth and scales. The teeth belong to three genera: Phoebodus, Cladodoides and Protacrodus. The comparison with selected Late Frasnian chondrich- thyan assemblages from the seas between Laurussia and Gondwana revealed substantial local differences of taxonomic composition due to palaeoenvironmental conditions, such as depth, distance to submarine platforms, oxygenation of water, and possibly also temperature. The assemblage from Belgium, with its high frequency of phoebodonts, is the most similar to that from the Ryauzyak section, South Urals, Russia, and the Horse Spring section, Canning Basin, Australia. Key words: Late Devonian; Belgium; Dinant Synclinorium; Chondrichthyes; Microfossils. INTRODUCTION in several of the collection samples (Collections of the Royal Belgian Institute for Natural Sciences, Excavation in the Lompret Quarry expanded north- Brussels, Belgium).
    [Show full text]
  • Copyrighted Material
    06_250317 part1-3.qxd 12/13/05 7:32 PM Page 15 Phylum Chordata Chordates are placed in the superphylum Deuterostomia. The possible rela- tionships of the chordates and deuterostomes to other metazoans are dis- cussed in Halanych (2004). He restricts the taxon of deuterostomes to the chordates and their proposed immediate sister group, a taxon comprising the hemichordates, echinoderms, and the wormlike Xenoturbella. The phylum Chordata has been used by most recent workers to encompass members of the subphyla Urochordata (tunicates or sea-squirts), Cephalochordata (lancelets), and Craniata (fishes, amphibians, reptiles, birds, and mammals). The Cephalochordata and Craniata form a mono- phyletic group (e.g., Cameron et al., 2000; Halanych, 2004). Much disagree- ment exists concerning the interrelationships and classification of the Chordata, and the inclusion of the urochordates as sister to the cephalochor- dates and craniates is not as broadly held as the sister-group relationship of cephalochordates and craniates (Halanych, 2004). Many excitingCOPYRIGHTED fossil finds in recent years MATERIAL reveal what the first fishes may have looked like, and these finds push the fossil record of fishes back into the early Cambrian, far further back than previously known. There is still much difference of opinion on the phylogenetic position of these new Cambrian species, and many new discoveries and changes in early fish systematics may be expected over the next decade. As noted by Halanych (2004), D.-G. (D.) Shu and collaborators have discovered fossil ascidians (e.g., Cheungkongella), cephalochordate-like yunnanozoans (Haikouella and Yunnanozoon), and jaw- less craniates (Myllokunmingia, and its junior synonym Haikouichthys) over the 15 06_250317 part1-3.qxd 12/13/05 7:32 PM Page 16 16 Fishes of the World last few years that push the origins of these three major taxa at least into the Lower Cambrian (approximately 530–540 million years ago).
    [Show full text]
  • Database of Bibliography of Living/Fossil
    www.shark-references.com Version 16.01.2018 Bibliography database of living/fossil sharks, rays and chimaeras (Chondrichthyes: Elasmobranchii, Holocephali) Papers of the year 2017 published by Jürgen Pollerspöck, Benediktinerring 34, 94569 Stephansposching, Germany and Nicolas Straube, Munich, Germany ISSN: 2195-6499 DOI: 10.13140/RG.2.2.32409.72801 copyright by the authors 1 please inform us about missing papers: [email protected] www.shark-references.com Version 16.01.2018 Abstract: This paper contains a collection of 817 citations (no conference abstracts) on topics related to extant and extinct Chondrichthyes (sharks, rays, and chimaeras) as well as a list of Chondrichthyan species and hosted parasites newly described in 2017. The list is the result of regular queries in numerous journals, books and online publications. It provides a complete list of publication citations as well as a database report containing rearranged subsets of the list sorted by the keyword statistics, extant and extinct genera and species descriptions from the years 2000 to 2017, list of descriptions of extinct and extant species from 2017, parasitology, reproduction, distribution, diet, conservation, and taxonomy. The paper is intended to be consulted for information. In addition, we provide data information on the geographic and depth distribution of newly described species, i.e. the type specimens from the years 1990 to 2017 in a hot spot analysis. New in this year's POTY is the subheader "biodiversity" comprising a complete list of all valid chimaeriform, selachian and batoid species, as well as a list of the top 20 most researched chondrichthyan species. Please note that the content of this paper has been compiled to the best of our abilities based on current knowledge and practice, however, possible errors cannot entirely be excluded.
    [Show full text]
  • Color and Learn: Sharks of Massachusetts!
    COLOR AND LEARN: SHARKS OF MASSACHUSETTS! This book belongs to: WHAT IS A SHARK? Sharks are fish that have vertebrae (skeletons) made ofcartilage instead of bones. Sharks come in all different shapes, sizes, and colors. Sharks have different kinds of teeth, feeding patterns, swimming styles, and behaviors that help them to survive in all different kinds of aquatic habitats! Can you label the different parts of a shark? second dorsal fin caudal (tail) fin pelvic fin gills anal fin pectoral fin nostril mouth eye Dorsal fin There are around 500 species of sharks in the world. Massachusetts coastal waters provide ideal habitat for several kinds of Atlantic Ocean sharks that visit our waters each season! Massachusetts HOW LONG HAVE SHARKS BEEN ON EARTH? Sharks have been on Earth since before the dinosaurs! Scientists learn about early sharks by studying fossils. Shark fossils can tell us a lot about what food the shark ate, what their habitat looked like, and how they are related to other sharks. The ancient sharks on this page are extinct. Acanthodes (ah-can-tho-deez), or “spiny shark,” was the first fish to have a cartilage skeleton! Cladoselache (clay-do-sel-ah-kee) had a body and tail shaped for swimming fast. It did not have the same kind of skin that we see in modern sharks today. Stethacanthus (stef-ah-can-thus), or “anvil shark”, had a dorsal fin shaped like an ironing board! 450 370 360 200 145 60 6.5 MILLIONS OF YEARS AGO DINOSAURS EVOLVE WHAT ARE “MODERN” SHARKS? “Modern” sharks are species that have body parts (both inside and out!) that can be found on sharks living today.
    [Show full text]