46 research outputs found

    Schmidtites celatus (Obolida, Brachiopoda) from the "Obolus sands" (Upper Cambrian - Lower Ordovician) of Estonia

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    International audienceLarge collections of the brachiopod obolid Schmidtites celatus have been gathered from Upper Cambrian-Lower Ordovician strata in four northern Estonian localities. The morphological features and the taxonomic characters of the genus and of the single species representing it are re-described and illustrated. New diagnoses are proposed based on characters of the shell and morphological traits that permit Schmidtites celatus to be compared with and distinguished from the other obolid genera occurring in the same samples or areas, i.e. Ungula ingrica, Oepikites, and Obolus apollinis which now includes specimens formerly described as Ungula convexa. Schmidtites celatus differs from them mainly in the arrangement of its musculature

    Tools for linguloid taxonomy: the genus Obolus (Brachiopoda) as an example

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    International audienceThis study points out some basic problems of linguloid systematics and proposes solutions for them. A taxonomic examination of the unique species of the genus Obolus found in the Upper Cambrian of Estonia and Russia, O. apollinis (= O. ruchini, O. transversus, O. rebrovi and Ungula convexa) is used as an example of a methodology employing all of the characters valid for distinguishing species of both extant and fossil Lingulidae. These characters are: - umbonal region; - body musculature; - septa or ridges; - main mantle canals - as established and figured by EMIG (1982, 1983) and BIERNAT and EMIG (1993). All of them have been determined to be taxonomically stable and have been studied and compared to take into account intraspecific variability; they should be used to describe or to redescribe any taxon of the superfamily Linguloidea. Characters of the shell and valves, such as shape, size, and dimensional ratios have no taxonomic value. ––– Des outils pour la taxinomie des Lingulidoida : le genre Obolus (Brachiopoda) pris comme exemple.- Cette Ă©tude met en exergue des problĂšmes fondamentaux de la systĂ©matique des LinguloĂŻdes et propose des solutions mĂ©thodologiques basĂ©es sur les caractĂšres utilisĂ©s pour identifier les espĂšces de Lingulides actuelles et fossiles. L'unique espĂšce du genre Obolus, O. apollinis (= O. ruchini, O. transversus, O. rebrovi and Ungula convexa), rĂ©coltĂ©e dans divers gisements du Cambrien moyen et supĂ©rieur en Estonie et Russie, sert ici d'exemple. Les caractĂšres sont : - la rĂ©gion umbonale ; - la musculature du corps ; - les septums et crĂȘtes internes ; - les canaux du manteau ; selon la description et la reprĂ©sentation faites par EMIG (1982, 1983) et BIERNAT et EMIG (1993). Tous ces caractĂšres se sont rĂ©vĂ©lĂ©s taxinomiquement stables tout en prĂ©sentant une relative variabilitĂ© intraspĂ©cifique ; ils sont donc Ă  ĂȘtre utilisĂ©s pour dĂ©crire ou redĂ©crire tous les taxons de la superfamille des Linguloidea. Il convient de souligner que les caractĂšres de la coquille ou des valves, tels que formes, tailles, rapports dimensionnels n'ont aucune valeur taxinomique

    Proof that Lingula (Brachiopoda) is not a living-fossil, and emended diagnoses of the Family Lingulidae

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    International audienceLingula is often considered a "living-fossil" based on its supposed lengthy morphological conservatism owing to its absence of evolution, and its remarkable survival for more than 550 M.Y. This conclusion is based on the typical apparently unchanged "linguliform" shape of the shell. However the taxa of the family Lingulidae show morphological evolutionary changes despite the fact that the group appears panchronic among the Recent Brachiopoda. Consequently, traditional opinion that Lingula is a "living-fossil" should be rejected. Diagnoses of the Family Lingulidae and of its three genera are herewith emended. RĂ©sumĂ© : Preuves que Lingula (Brachiopoda) n'est pas un fossile vivant, avec de nouvelles diagnoses pour les taxons de la Famille des Lingulidae. ––– Lingula est souvent considĂ©rĂ©e comme un fossile-vivant, voire le plus ancien actuellement connu, Ă  cause de son long conservatisme morphologique basĂ© sur une supposĂ©e absence d'Ă©volution, ainsi qu'en raison de sa remarquable survie depuis plus de 550 MA. Cette assertion est basĂ©e sur une forme inchangĂ©e de la coquille, dite "linguliforme". Cependant, les taxons de la famille des Lingulidae montrent des changements Ă©volutifs de la morphologie et de l'anatomie interne bien que ce groupe puisse ĂȘtre considĂ©rĂ© comme panchronique au sein des Brachiopoda actuels. Il est dĂ©montrĂ© que l'opinion traditionnellement vĂ©hiculĂ©e selon laquelle les Lingula seraient des fossiles vivants doit ĂȘtre rejetĂ©e. En consĂ©quence, de nouvelles diagnoses sont proposĂ©es pour la famille des Lingulidae et pour les trois genres pouvant s'y rapporter avec certitude

    Reply to L.E. POPOV and L.E. HOLMER (CG2003_A06_LEP-LEH): Obolid taxonomy

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    International audienceReply to L.E. POPOV and L.E. HOLMER (2003): Obolid taxonom

    Nummulus brattenburgensis et Crania craniolaris (Brachiopoda, Craniidae)

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    Les pences de Brattingsborg (ou Brattenburg) sont connus depuis le milieu du premier millĂ©naire et beaucoup de lĂ©gendes mĂ©diĂ©vales populaires attribuent leur origine sur l'Ăźle Ivö en Scanie (SuĂšde) oĂč ils sont appelĂ©s "brattingsborgpenningar" ou en latin comme Nummulus brattenburgensis. En rĂ©alitĂ©, ce sont des valves du brachiopode fossile Crania craniolaris dĂ©crit par LINNÉ (1758) sous Anomia craniolaris et en partie de valves d'Isocrania egnabergensis dĂ©crit par RETZIUS (1781) dans le CrĂ©tacĂ© SupĂ©rieur de Scanie. Le genre Crania basĂ© sur ces deux espĂšces rĂ©coltĂ©es Ă  Ivö, Balsberg et Ignaberga a Ă©tĂ© crĂ©Ă© par RETZIUS (1781). Deux des lĂ©gendes, cĂ©lĂšbres en Scandinavie, sont briĂšvement contĂ©es. L'histoire scientifique de ces deux espĂšces et d'une troisiĂšme Danocrania tuberculata (NILSSON, 1826), autrefois figurĂ©e sous Craniolites brattenburgicus du Danien de Scanie, est dĂ©crite et commentĂ©e.The Brattingsborg pennies are mentioned in medieval texts dating from the middle of the first millennium and many popular medieval legends refer to their occurrence on Ivö Island in the Scania region (Sweden) as brattingsborgpenningar or in Latin as Nummulus brattenburgensis. Actually they are valves of the fossil brachiopod Crania craniolaris originally described by LINNAEUS (1758) as Anomia craniolaris from the Upper Cretaceous. Later RETZIUS (1781) created the genus Crania based on these specimens from Ivö Island and on another species he described under Crania (now Isocrania) egnabergensis from Ignaberga in the Scania region. The scientific history of those two species is reviewed along with that of Danocrania tuberculata (NILSSON, 1826), formerly figured as Craniolites brattenburgicus, from the Danian of Scania. Two legends about these "pennies" are included

    Revision of the brachiopod species described by A. RISSO

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    Although RISSO's collection has not been found, the current list of twelve recent brachiopod species and thirteen fossil ones iden-tified and described by RISSO (1826) in the marine and terrestrial vicinities of Nice deserves revision by taking into account the synonyms accepted today. Adding Argyrotheca cistellula reported in 1920, the list of the extant species of brachiopods collected in the Mediterranean Sea has remained the same until 1994, date from which it increases by two species. Three of the species described by RISSO as belonging to Terebratula have been attributed as new species to him: Joania cordata, Argyrotheca cuneata, Lacazella mediterranea, all three are type species of their genus. For the fossil species, only two were identified as synonyms for Terebratula terebratula. Criticized several times, sometimes too severely, for his works on the Mollusca, to which the Brachiopoda were attributed, RISSO (1826) as an amateur naturalist completed a honourable work on this latter group, entirely comparable with those of the majority of its contemporaries and more recent authors on this group.Bien que la collection RISSO n'ait pas Ă©tĂ© retrouvĂ©e, la liste de douze espĂšces actuelles et treize espĂšces fossiles de brachiopodes recensĂ©es et dĂ©crites par RISSO (1826) dans les environs mari-times et terrestres de Nice mĂ©rite rĂ©vision en prenant en compte les mises en synonymie rĂ©centes. En y ajoutant Argyrotheca cistellula signalĂ©e en 1920, la liste des espĂšces actuelles de brachiopodes rĂ©col-tĂ©es en mer MĂ©diterranĂ©e est restĂ©e la mĂȘme jusqu'en 1994, date Ă  partir de laquelle elle augmente de deux espĂšces. Trois des espĂšces dĂ©crites par RISSO sous le nom de genre Terebratula lui restent attri-buĂ©es : Joania cordata, Argyrotheca cuneata, Lacazella mediterranea, elles sont toutes trois l'espĂšce-type de leur genre. Quant aux espĂšces fossiles, seules deux ont pu ĂȘtre identifiĂ©es, comme synonymes de Terebratula terebratula. Plusieurs fois critiquĂ©, parfois avec trop de sĂ©vĂ©ritĂ©, pour ses travaux sur les Mollusques, auxquels appartenaient aussi Ă  l'Ă©poque les Brachiopodes, RISSO (1826) comme natu-raliste amateur a rĂ©alisĂ© un travail parfaitement honorable sur les Brachiopodes, en tout comparable Ă  ceux de la plupart de ses contemporains et successeurs sur ce groupe

    Des outils pour la taxinomie des Lingulidoida : le genre Obolus (Brachiopoda) priscomme exemple

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    Cette Ă©tude met en exergue des problĂšmes fondamentaux de la systĂ©matique des LinguloĂŻdes et propose des solutions mĂ©thodologiques basĂ©es sur les caractĂšres utilisĂ©s pour identifier les espĂšces de Lingulides actuelles et fossiles. L'unique espĂšce du genre Obolus, O. apollinis (= O. ruchini, O. transversus, O. rebrovi and Ungula convexa), rĂ©coltĂ©e dans divers gisements du Cambrien moyen et supĂ©rieur en Estonie et Russie, sert ici d'exemple. Les caractĂšres sont : - la rĂ©gion umbonale ; - la musculature du corps ; - les septums et crĂȘtes internes ; - les canaux du manteau ; selon la description et la reprĂ©sentation faites par EMIG (1982, 1983) et BIERNAT et EMIG (1993). Tous ces caractĂšres se sont rĂ©vĂ©lĂ©s taxinomiquement stables tout en prĂ©sentant une relative variabilitĂ© intraspĂ©cifique ; ils sont donc Ă  ĂȘtre utilisĂ©s pour dĂ©crire ou redĂ©crire tous les taxons de la superfamille des Linguloidea. Il convient de souligner que les caractĂšres de la coquille ou des valves, tels que formes, tailles, rapports dimensionnels n'ont aucune valeur taxinomique.This study points out some basic problems of linguloid systematics and proposes solutions for them. A taxonomic examination of the unique species of the genus Obolus found in the Upper Cambrian of Estonia and Russia, O. apollinis (= O. ruchini, O. transversus, O. rebrovi and Ungula convexa) is used as an example of a methodology employing all of the characters valid for distinguishing species of both extant and fossil Lingulidae. These characters are: - umbonal region; - body musculature; - septa or ridges; - main mantle canals - as established and figured by EMIG (1982, 1983) and BIERNAT and EMIG (1993). All of them have been determined to be taxonomically stable and have been studied and compared to take into account intraspecific variability; they should be used to describe or to redescribe any taxon of the superfamily Linguloidea. Characters of the shell and valves, such as shape, size, and dimensional ratios have no taxonomic value
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