Cruziana traces from the Late Silurian (Pridoli) carbonate shelf of Saaremaa, Estonia

Late Pridoli Cruziana traces have recently been found in carbonate shelf sediments of the Ohesaare Formation on Saaremaa Island, Estonia. Cruziana isp. is interpreted here as a locomotory trace (repichnia) of an arthropod, possibly a trilobite. Cruziana traces previously known from the Silurian of Baltica differ from Cruziana isp., indicating that the diversity of Cruziana traces in the late Silurian of Baltica was higher than previously thought

Morphogenesis and phylogenetic relationships of clitambonitidines, Ordovician brachiopods

http://www.ester.ee/record=b1409031~S1*es

Cornulitid epibionts on brachiopod shells from the Late Ordovician (middle Ashgill) of East China

This is the first record of Cornulites sp. as an epibiont on brachiopods from the middle Ashgill, Late Ordovician, of the South China Palaeoplate. Twenty-one cornulitid specimens were found attached to the brachiopod shells of Altaethyrella zhejiangensis and Ovalospira dichotoma. Both the location of cornulitids and their orientation on the brachiopod shells indicate a possible commensal relationship between the cornulitids and their hosts

Russell H. Vinn to Dr. Silver, 8 July 1956

Personal correspondenc

New late ordovician cornulitids from peru

Two new species of cornulitids, Cornulites zatoni sp. nov. and Cornulites vilcae sp. nov., are described from the lower part (Sandbian) of the Calapuja Formation of south-western Peru. Late Ordovician cornulitid diversities of Peru (Gondwana) and Estonia (Baltica) are similar. Aggregative growth form dominates among the cornulitids of the Sandbian of Peru. Multiple oriented C. zatoni sp. nov. specimens on a strophomenid brachiopod likely represent a syn vivo encrustation. Cornulitids from the Sandbian of Peru differ from those known from the Sandbian of Baltica. C. zatoni sp. nov. possibly also occurs in the Late Ordovician of Laurentia. © 2016, Czech Geological Survey. All rights reserved.Peer reviewe

A new species of Conchicolites (Cornulitida, Tentaculita) from the Wenlock of Gotland, Sweden

A new cornulitid species, Conchicolites crispisulcans sp. nov., is described from the Wenlock of Gotland, Sweden. The undulating edge of C. crispisulcans sp. nov. peristomes is unique among the species of Conchicolites. This undulating peristome edge may reflect the position of setae at the tube aperture. The presence of the undulating peristome edge supports the hypothesis that cornulitids had setae and were probably related to brachiopods

Ichnofossiles associés à des coquilles de lingulides du Permien inférieur du Brésil.

Lingulides from Lower Permian of Brazil (24% substrates) showed signs of bioerosion in form of multiple small shallow pits that resemble incomplete Oichnus paraboloides borings. A single lingulide valve showed a centrally located large circular predatory Oichnus simplex boring. Several lingulide shells (c. 21%) show small Arachnostega traces in their interior. The diameter of Arachnostega burrows is relatively constant. These burrows are more similar to juvenile stages of Arachnostega gastrochaena and do not form well-developed meshwork of tunnels. This is the first record of Arachnostega from the interior of lingulide shells and indicates that even very small lingulide shells were suitable substrates for cryptic organisms.Les lingulides du Permien inférieur du Brésil (24% des substrats) portent des traces de bio-érosion sous forme de nombreux petits trous peu profonds qui ressemblent à des perforations incomplètes d'Oichnus paraboloides. Une seule coquille de lingulide montre une grande perforation prédatrice circulaire d'Oichnus simplex localisée en son centre. Plusieurs coquilles de lingulides (environ 21%) présentent des traces d'Arachnostega à l'intérieur. Le diamètre des terriers d'Arachnostega est relativement constant. Ces terriers sont très semblables aux stades juvéniles d'Arachnostega gastrochaena et ne forment pas de réseaux de tunnels bien développés. C'est la première mention d'Arachnostega à l'intérieur de coquilles de lingulides et ce qui prouve que des coquilles de lingulides, même très petites, pouvaient constituer un substrat convenable pour des organismes cryptiques

A new microconchid species from the Silurian of Baltica

The diversity of Silurian microconchids is still poorly understood. Here, a new microconchid tubeworm species, Palaeoconchus wilsoni, is described from the Silurian (Ludlow) encrusting rugose corals from Estonia (Saaremaa Island) and a brachiopod shell from Sweden (Gotland). In Estonia, the microconchids are a dominant constituent of the encrusting assemblages, associated with cornulitids, Anticalyptraea, auloporids, trepostome bryozoans, hederelloids and enigmatic ascodictyids. It is notable that these Silurian encrusting assemblages are clearly dominated by tentaculitoids (microconchids, cornulitids and Anticalyptraea) which very often co-exist on the same coral host. Morphologically similar microconchids and Anticalyptraea may have exploited a more similar ecological niche than the straight-shelled cornulitids. However, the clear predominance of microconchids over Anticalyptraea in the communities may indicate that this genus was a less effective competitor for food than microconchid tubeworms

Le rôle d'un revêtement organique interne dans la biominéralisation de tubes de serpulidés

La plupart des ultrastructures biominéralisées observées au contact du revêtement orga-nique interne du tube des serpulidés ne présentent pas d'indices de croissance directionnelle. Cepen-dant des structures sphérolitiques prismatiques observées sur la face interne du tube de formes mo-dernes telles que Crucigera websteri, C. zygophora, Floriprostis sabiuraensis et Pyrgopolon ctenactis indiquent que cette structuration s'accroît en direction de la couche organique interne et aussi vers la lumière du tube. Cette direction de croissance s'observe également chez un Hydroides sp. du Miocène d'Autriche. Elle est contraire à celle qu'on attendrait dans l'hypothèse où le revêtement organique interne ne jouerait que le rôle de simple support dans la biominéralisation du tube en CaCO3.Most known serpulid tube ultrastructures in contact with an organic inner tube lining do not show the direction in which they developed. But spherulitic prismatic structures found in the innermost part of the tube wall of Recent Crucigera websteri, C. zygophora, Floriprotis sabiuraensis, and Pyrgopo-lon ctenactis indicate that the structure grew toward the organic inner tube lining and also toward the tube's lumen. Similar directions of growth for this structure are seen in Hydroides sp. from the Miocene of Austria. Growth towards the tube's lumen is opposite to what one would expect if the organic inner tube lining is being used as a scaffold for the biomineralization of CaCO3