Hoffmanigraptus n. gen., a new retiolitine (Graptolithina), an early member of the Plectograptus lineage from the Silurian of Baltica, Poland

Most upper Homerian and Ludfordian retiolitines have a tubarium with hexagonal meshes and a zigzag pattern in the middle part of their lateral walls, a shallow ancora umbrella, and a free nema. Hoffmanigraptus varsoviensis n. gen., n. sp. is described from isolated, three-dimensional material, from the upper part of the Colonograptus praedeubeli Biozone (upper Homerian, Silurian) of Poland, Baltica, and represents one of the earliest forms with this construction. This type of tubarium is represented by the upper Homerian Doliograptus Lenz & Kozłowska-Dawidziuk, 2002 and Spinograptus Bouček & Münch, 1952, differing from Hoffmanigraptus n. gen. mainly in larger proximal lateral orifices, pattern of clathrial lists on lateral walls, as well as size and shape of tubaria. Hoffmanigraptus n. gen. has a tubarium widening medially, tapering towards the distal end and forming a finite tubarium, with a possible three-vaned nematularium. Flattened specimens Plectograptus? ovatus Kozłowska, Lenz & Štorch, 2001 and Plectograptus? karlsteinensis Kozłowska, Lenz & Štorch, 2001, preserved on a rock surface from the Barrandian area are assigned to the new genus. They are of the same upper Homerian age, and show the main features of the new form. Hoffmanigraptus n. gen. is regarded as an early member of the Plectograptus clade.

Early complex tiering pattern: Upper Ordovician, Barrandian area, the Czech Republic

Upper Ordovician shallow marine fine-grained sandstones and siltstones exposed in the Loděnice – vinice locality yielded a distinct and well-preserved tiering pattern of trace fossils. The two uppermost tiers are composed mainly of Bifungites and Nereites. Deeper in the sediment, tiers dominated by Thalassinoides, Zoophycos and Teichichnus occur. Most of the succession is completely bioturbated; however, several storm layers enabled study of a well-preserved frozen tiering pattern. Large portions of the bedding planes (ichnologic snapshots) showed a considerable patchiness of intensive surface bioturbation and a preferred orientation of Bifungites. The identified tiering pattern is one of the earliest examples of a well-documented complex tiering of burrows documented in detail.

The Cuticles of (?) Thylacocephalan Arthropod from the Basal Choteč Event (Choteč Formation, Eifelian; Barrandian Area, Czech Republic)

Small fragments of phosphatic cuticle have been observed in dark limestone of the early Eifelian age (Choteč Formation) in the interval of the Basal Choteč Event. The cuticle is two-layered, primarily folded, with a chamber between outer and inner walls. Fragments likely represent small cuticle pieces from the margins of the carapace. The exterior of the cuticle is nearly smooth bearing irregular network of wrinkled polygons or shallow pits. Low conical mound-like to high thorn-like spines with annular structure extend from both outer and inner surface of cuticle. Wrinkled and folded bases of these spines indicate moderate flexibility of cuticle. Spines are hollow, the higher ones often with apical opening. The inner surface of carapace carries smaller spines or is nearly smooth. Chamber walls inside the cara-pace are with folds and other structures supporting stiffness of the cuticle. The internal walls of the cuticle are covered by polygonal bumps. These uniformly sized and shaped bumps are about 1 μm sized and likely represents imprints of the epithelial cells adjoined to the basal membranous layer of endocuticle.Biological affinity of cuticle fragments is unclear. They surely represent pieces of the arthropod cara-pace, the most probably a thylacocephalan. Associated fossils indicate a deeper marine environment. Bloom of prasinophytes, abundance of dacryoconarids and organophosphatic brachiopods, and striking rarity and diminutive size of other fauna indicate eutrophic conditions in a neritic sea, likely with hypoxic bottom water. Nectonic mode of life in open sea can be suggested for an animal bearing this cuticle.

Vzácný allanpringit - produkt alterace fluorwavellitu z lomu Milina u Zaječova (Česká republika)

A very rare phosphate allanpringite was found in the abandoned quarry Milina near Zaječov, Czech Republic in Ordovician sediments of the Barrandian area. Allanpringite forms yellow powder and earthy aggregates. In a more detailed study using SEM microscope, allanpringite forms rod-shaped and tabular crystals. Its origin is associated with alteration of fluorwavellite. Empirical formula of the allanprigite is (Fe2.70Al0.24)Σ2.94(PO4)2.00(OH)2.83·5H2O and refined unit-cell parameters are a 9.774(5), b 7.361(3), c 17.826(8) Å, β 92.2(6)° and V 1281.5(9) Å3. Allanpringite was found in association with jarosite, variscite and partly altered fluorwavellite.

Cambrian hyoliths of the Příbram-Jince Basin (Barrandian area, the Czech Republic): A review of recorded taxa

Hyoliths recorded from the middle Cambrian Jince Formation of the Barrandian area in the Czech Republic are reviewed and listed, based on various published papers printed since 1854. Up to now, only five species of hyolithids and three species of orthothecids have been reported, classified within seven genera. The reported material was collected from more than twenty small occasional outcrops and/or sections measuring up to several tens of meters in thickness, all situated exclusively in the area between the villages Felbabka and Čenkov in the Litavka River Valley. From the Paseky Shale member of the Holšiny-Hořice Formation at the Medalův mlýn locality, the first hyolith classified as “Hyolith genus and species indeterminate” is described. The new study of two specimens described and figured by Barrande in 1867 as Hyolithes primus made it possible to classify them as Jincelites vogeli and Jincelites sp. respectively.