brachiopoda Index du Forum

brachiopoda
Forum Français sur les brachiopodes fossiles et actuels.

 FAQFAQ   RechercherRechercher   MembresMembres   GroupesGroupes   S’enregistrerS’enregistrer 
 ProfilProfil   Se connecter pour vérifier ses messages privésSe connecter pour vérifier ses messages privés   ConnexionConnexion 

Flabellulirostrum sp.2

 
Poster un nouveau sujet   Répondre au sujet    brachiopoda Index du Forum -> Brachiopodes identifiés -> Ordre des RHYNCHONELLIDA
Sujet précédent :: Sujet suivant  
Auteur Message
Vandenbos


Hors ligne

Inscrit le: 22 Oct 2014
Messages: 273
Localisation: Maubeuge
Masculin

MessagePosté le: Dim 20 Aoû - 14:04 (2017)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

  J'ai originellement attribué cette forme au genre Phlogoiderhynchus. Pour l'heure, je serais enclin à modifier cette première attribution. En effet, nombre de ses caractères la rapprocherait davantage du genre Flabellulirostrum. La coquille est de taille petite à moyenne, généralement plus large que longue, fortement biconvexe, inéquivalve, de contours sub-circulaire ou sub-pentagonale. Le sinus est large, tardif, peu profond, à fond plat ou légèrement convexe. Le bourrelet est également tardif, s'élargissant rapidement avant de se redresser à son extrémité. Les flancs et les umbos sont convexes et lisses et le crochet très petit et recourbé. L'ornementation se compose de côtes tardives, larges et arrondies, séparées les unes des autres par d'étroits sillons. On en dénombre environ huit sur chacun des flancs et de trois à cinq dans le sinus et sur le bourrelet. Notons quelques rares individus plus globuleux, avec une hauteur totale beaucoup plus importante. Les différences avec Flabellulirostrum sp.1 peuvent se résumer à: une taille plus faible, une largeur moins importante, une forme générale plus arrondie, une commissure frontale en forme de U inversé, des flancs nettement convexes et des extrémités latérales arrondies. Cette Rhynchonelle se rencontre dans le Frasnien supérieur, formation de Neuville, le long de la partie sud occidentale du synclinal de Dinant (Franes les Couvins, Vaux, Robechies).
   Formerly, I assigned this form to the genus Phlogoiderhynchus, but numerous of features are more characteristic of Flabellulirostrum. It's shell is small to middle size, generally widder than long, strongly biconvex, inequivalve with subcircular to subpentagonal shape. Sulcus and fold are respectively, wide, late, shallow with flat or slightly convex bottom for the first, and late, quickly widden before raising at its extremity for the second. Slopes are very convex and the small beak is curved. Ribs are late, wide, rounded, separated by narrow furrows. We count among eight on each side and three to five in the sulcus or on the fold. Some rare samples are more globular with more important height. The differences between Flabellulirostrum sp.1 and sp.2 can be sum up bellow by: a smaller size, a width less important, a more rounded shape, a frontal commissure in the shape of a reverse U, convex slopes and rounded extremities. For now, this Flabellulirostrum is known alongside the south western margin of the Dinant synclinorium, within the Neuville formation (upper Frasnian).


  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 



  Flabellulirostrum sp.2, upper Frasnian, Neuville formation, greenish and nodular shales, Vaux (Belgium).     
_________________
Gervais Vandenbos, alias Brachiopathe
Revenir en haut
Publicité






MessagePosté le: Dim 20 Aoû - 14:04 (2017)    Sujet du message: Publicité

PublicitéSupprimer les publicités ?
Revenir en haut
Juergen


Hors ligne

Inscrit le: 16 Juin 2013
Messages: 204
Localisation: D - Nuremberg region
Masculin

MessagePosté le: Ven 12 Oct - 16:00 (2018)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

Hi Gervais,


I work together with Nils Jung. I guess you know him. He has shown you some brachiopods we are just discussing about. In general I agree to your opinion that the bigger and broader one (Fig. 1) is Navalicria compacta and the smaller ones (Fig. 2 and 3) an undiscribed Flabellulirostrum species. But the very globose form being as long as broad and having a long rectangular tongue (Fig. 4) is from my point of view another species. You have depicted specimens of this form in the 3rd row. Can you follow my opinion? If yes, do you have any idea what species it could be?


For all others I will show the specimens under discussed below. They come from a small outcrop beside the street between Villeres and Lompret near Vaulx and the Rue Les Quartiers. I do not know the precise formation. I assumed that it could be Grands Breux Fm., because the quarry in Lompret offers Grands Breux Fm. But Neuville Fm. is possible, too.



Best regards,


Jürgen





Fig. 1 (l=18mm)





Fig. 2 (l=13mm)





Fig. 3 (l=14mm)




Fig. 4 (l=14mm)
_________________
Revenir en haut
Vandenbos


Hors ligne

Inscrit le: 22 Oct 2014
Messages: 273
Localisation: Maubeuge
Masculin

MessagePosté le: Lun 15 Oct - 17:23 (2018)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

Hi Juergen,
About this species and according to me, I'm not sure that the most inflated belong to another species. They're just a little less frequent but found always associated with the other "form" and also Navalicria compacta, Thomasaria altumbona, Biernatella abunda and rare Atrypids as Iowatrypa (not biohermal species). In fact, I belive that it's a morphological varying of the first, more spherical. Concerning now the Lompret quarry (Lahonry quarry), to my knowledge, the Grand Breux formation is not present, but Neuville and Matagne formations. Contrary to Vaux, wich is close by, you can find a biohermal unit (Petit-Mont member), as Trélon, but with scarse fauna and I have not found there Rhynchonellids yet. The different units of this quarry are described briefly by Goolaerts and Grouwy in 2015: The Lahonry quarry at Lompret, Belgium: an extraordinary new site to study upper frasnian Cephalopods during the onset of anoxia in the Dinant basin, Strata plubisher and now available on the net. I hope that these few informations will be useful for you. Best regards, Gervais.



_________________
Gervais Vandenbos, alias Brachiopathe
Revenir en haut
Juergen


Hors ligne

Inscrit le: 16 Juin 2013
Messages: 204
Localisation: D - Nuremberg region
Masculin

MessagePosté le: Mar 16 Oct - 10:57 (2018)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

Hi Gervais,


thanks a lot for that detailed answer. Indeed, they are very useful. You've convinced me that all specimens are of same species. I assume that the outcrop is in the Neuville formation. By the way, I like your presentation of all these Belgian brachiopods on this platform. It is a pity that only a few users are active on this site.


Cheers,


Jürgen
_________________
Revenir en haut
Vandenbos


Hors ligne

Inscrit le: 22 Oct 2014
Messages: 273
Localisation: Maubeuge
Masculin

MessagePosté le: Mer 17 Oct - 12:35 (2018)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

Hi Jürgen. Indeed, it's a rare desease which affect only some privileged people. Concerning the Vaulx section, the accessible part concerns only the Neuville formation and the basal part of the the Matagne formation. It's a road outcop, or rather situated on a short blind road, along the N-939 road. Rocks, concerning the Neuville formation, are brownish nodular shales. Additional data can be obtained in the Godefroid and Helsen's file: The last frasnian Atrypida in southern Belgium, Acta paleontologica polonica, 1998, well on available online. I asked to Nils if he wished more samples, just have found in a box. I think that he's going to speak to you. If you are interested about it, don't hesitate. For me it will be always a pleasure. Friendly, Gervais.
_________________
Gervais Vandenbos, alias Brachiopathe
Revenir en haut
Juergen


Hors ligne

Inscrit le: 16 Juin 2013
Messages: 204
Localisation: D - Nuremberg region
Masculin

MessagePosté le: Mer 17 Oct - 15:41 (2018)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

Hi Gervais,


thanks for your offer to pride us with specimens from your collection. That might be helpful. In our paper, which is under work, we intend to take all Belgian Rhynchonellids into account, which have a small chance to occur in the Aix la Chapelle or western Eifel region. Paul Sartenaer has done a lot of work on the brachiopods in that area. Nethertheless, there are still many questions open and determination problems to be solved. Nothing is easy in that business.


All the best,


Jürgen   
_________________
Revenir en haut
Vandenbos


Hors ligne

Inscrit le: 22 Oct 2014
Messages: 273
Localisation: Maubeuge
Masculin

MessagePosté le: Jeu 18 Oct - 11:43 (2018)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

Hi Jürgen,
It' s on, there is some more determination work to achieve in the future. In spite of a relentless work, Paul Sartenaer did not describe all the species realy present in the upper Devonian from Ardennes area. Many of them remain unknown and undescribed. Do not forget to give me your postal address, and if you don't want to do it here, ask to Nils to communicate it on Facebook by private message. I'm going now to prepare you some Frasnian species and shall send them as soon as possible. I remain of course available. Best regards, Gervais. Okay
_________________
Gervais Vandenbos, alias Brachiopathe
Revenir en haut
Juergen


Hors ligne

Inscrit le: 16 Juin 2013
Messages: 204
Localisation: D - Nuremberg region
Masculin

MessagePosté le: Jeu 18 Oct - 12:10 (2018)    Sujet du message: Flabellulirostrum sp.2 Répondre en citant

Hi Gervais,


you are right. We should do our private communication outside this platform:
juergen.hoeflinger@o2online.de


Cheers, Jürgen
_________________
Revenir en haut
Contenu Sponsorisé






MessagePosté le: Aujourd’hui à 06:59 (2018)    Sujet du message: Flabellulirostrum sp.2

Revenir en haut
Montrer les messages depuis:   
Poster un nouveau sujet   Répondre au sujet    brachiopoda Index du Forum -> Brachiopodes identifiés -> Ordre des RHYNCHONELLIDA Toutes les heures sont au format GMT + 2 Heures
Page 1 sur 1

 
Sauter vers:  

Index | Panneau d’administration | faire son forum | Forum gratuit d’entraide | Annuaire des forums gratuits | Signaler une violation | Conditions générales d'utilisation
Powered by phpBB © 2001, 2005 phpBB Group
Traduction par : phpBB-fr.com