Coralliths of tabulate corals from the Devonian of the Holy Cross Mountains (Poland)

Tabulates, an extinct Palaeozoic group of corals, developed diverse colony morphologies during the Silurian to Devonian peak of reef development. Coralliths, or circumrotatory colonies, are passively motile coral colonies constantly overturned by wave action or currents. Such overturning allows tissue growth on all sides of the colony. They are among the most rarely reported growth forms. Recent corallith-forming scleractinian corals mostly inhabit the shallowest reef environments, but coralliths can also develop at greater depths in areas of low topographic relief, unconsolidated substratum, low coral cover and high water movement. Here, we report on Devonian (Givetian Favosites goldfussi and Frasnian Alveolites? tenuissimus) coralla from the Holy Cross Moun-tains, Poland. Our analysis suggests these colonies are coralliths, although less mature than usually reported. These corals, unlike previously described growth forms of this kind, lived in relatively deep environments: probably the upper mesophotic (Givetian, Miłoszów), or deep reef fore-slope (Frasnian, Jaźwica and Kowala). Microfacies analysis of the Ja ́zwica site suggests unconsolidated substratum and high hydrodynamic energy. We conclude that these corals lived in deeper environments where bottom currents caused their autorotation. A good modern analogue for such a corallith-forming environment is the Wistari Channel (Southern Great Barrier Reef), where bottom tidal currents at nearly 30 m of depth are strong enough to overturn colonies of Stylocoeniella cf. guentheri reaching 15 cm in diameter. Our discovery shows that the spectrum of coral growth forms during the Devonian peak of reef development was broader than previously assumed, and that tabulate corals displayed numerous adaptive strategies to various environments

Pre-Taghanic (Lower to lower Middle Givetian) brachiopods from Miłoszów in the Holy Cross Mountains (Poland)

Sixty-eight brachiopod species are reported from the upper part of the Skały Formation at Miłoszów (Łysogóry Region of the Holy Cross Mts., central Poland) on the basis of over 2,200 specimens. The fauna is Early to early Middle Givetian in age (timorensis to rhenanus/varcus conodont zones) and thus predates the Middle Givetian Taghanic Bioevent. One new genus and three new species are described. Leiocyrtia Baliński gen. nov. (type species: Leiocyrtia rara Baliński gen. et sp. nov.; Spiriferida, Cyrtiidae) is characterised by a non-costate shell with prominent sulcus and fold and capillate microornament. Undispirifer sidoniae Halamski and Baliński sp. nov. is characterised by transverse shells and dense ribbing. Moravilla andreae Baliński and Halamski sp. nov. is characterised by relatively coarse radial capillate ornament and is the first representative of the genus outside the type species from the Givetian of Moravia. The most abundant species are: Spinulicosta cf. spinulicosta, Antirhynchonella linguiformis, Pentamerelloides davidsoni, Peratos beyrichi, Plectospira ferita, Spinatrypa wotanica (confirmed to belong to that genus and not to Spinatrypina), Ambothyris sp., and Echinocoelia dorsoplana. ‘Spirifer’ quadriplicatus Sandberger and Sandberger, 1856, a rare species known from Miłoszów and the Rhenish Massif, is an orthide and belongs to Teichertina. The relationship between Skenidioides polonicus and S. cretus, formerly understood as anagenesis, is re-interpreted as budding cladogenesis. Davidsonia septata is reported as an epizoan on rugosan corals, a relationship never previously observed in representatives of that genus. Brachiopods represent different palaeoecological groupings, from relatively shallow-water taxa (BA3, globetum) to deep-water mud-dwelling ones (BA5, deeper brachiopodetum). The richest beds are M1-IIa (28 brachiopod species), M3-7 (23 species), and M0-9 (22 species). Eighteen species described here were not known previously in the Holy Cross Mountains, so the corrected total number of brachiopod species from the Middle Devonian of the Łysogóry Region is 140

Atrypides (Brachiopodes) frasniens de la Silésie (Pologne) et l’âge de la collision éo-varisque dans les Sudètes

La révision systématique des brachiopodes atrypides du Frasnien (Dévonien supérieur) de la Dépression de Świebodzice dans les Sudètes (Silésie, sud-ouest de la Pologne) conduit à reconnaître trois genres et trois espèces. Kyrtatrypa barnimi n. sp. est la première espèce du genre décrite du Frasnien supérieur et en est l’un des derniers représentants avant l’extinction des atrypides à la limite Frasnien-Famennien. Pseudogruenewaldtia tschernyschewi Rzhonsnitskaya, 1960 est décrite pour la première fois en dehors de ses localités-types dans le Timan. Sa présence permet de dater la faune entière du Frasnien supérieur. Spinatrypa mariaetheresiae n. sp. ressemble aux espèces contemporaines S. lambermontensis Mottequin, 2003 and S. rossica Rzhonsnitskaya in Rzhonsnitskaya et al., 1998 par une languette prononcée (peu importante chez la majorité des représentants du genre) mais elle en diffère par la densité de l’ornementation. Cette espèce possède deux morphotypes, situation analogue au dimorphisme décrit chez certaines Spinatrypina Rzhonsnitskaya, 1964. Un tableau synoptique résume la distribution des atrypides dans le Dévonien des Sudètes. Étant donné l’absence de conodontes et les doutes au sujet de l’âge des autres espèces de la macrofaune, les brachiopodes atrypides donnent actuellement la meilleure datation – un terminus ante quem pré-famennien – de la collision éo-varisque de la Bohême avec la Saxo-Thuringie.Frasnian (Late Devonian) Atrypida (Brachiopoda) from the Świebodzice Depression in the Sudetes (Silesia, south-western Poland) are revised. Three species are recognised. Kyrtatrypa barnimi n. sp. is the first described Late Frasnian species of the genus and one of the latest representatives of the genus before the atrypide extinction at the Frasnian-Famennian boundary. Pseudogruenewaldtia tschernyschewi Rzhonsnitskaya, 1960 is described for the first time outside the type area of the species, the Timan Mts. It allows to date the entire fauna to the Late Frasnian. Spinatrypa mariaetheresiae n. sp. is similar to coeval S. lambermontensis Mottequin, 2003 and S. rossica Rzhonsnitskaya in Rzhonsnitskaya et al., 1998 in having a high tongue (low in most representatives of the genus) but differs from them in ornamentation density. This species is represented by two morphotypes; an analogous dimorphism was described in some Spinatrypina Rzhonsnitskaya, 1964. A synoptic table of Devonian atrypides from the Sudetes is given. At present, given the lack of conodonts and unclear status of other diagnostic macrofauna, atrypide brachiopods are the best time markers giving a pre-Famennian terminus ante quem for the eo-Variscan collision of Bohemia and Saxothuringia.</p

Middle Devonian uncinuloids (Brachiopoda, Rhynchonellida) from North Africa and Central Europe

The paper includes a taxonomic revision of four externally similar Middle Devonian rhynchonellide species from northwestern Africa (Maïder, Tindouf Syncline) and Central Europe (Eifel, Bergisches Land, Holy Cross Mts.), considered in recent papers as representatives of Kransia Westbroek, 1967 or Nalivkinaria Rzhonsnitskaya, 1968. All four possess a septalium and a multilamellate cardinal process, the assignment to Nalivkinaria, having a bifid cardinal process, is therefore clearly inappropriate. Lebanzuella? issoumourensis (Drot, 1971) is present in the Givetian of Africa; two subspecies, L.? issoumourensis issoumourensis from Jbel Issoumour and L.? issoumourensis smarensis ssp. nov. from Western Sahara, are distinguished by their biometric characteristics. The other two species are included in Kransia (Fatimaerhynchia) subgen. nov. differing from Kransia (K.) in the presence of a septalium; the occurrence of such a variable structure is considered to be justification for distinction at the subgenus level. Kransia (Fatimaerhynchia) goldfussii (Schnur, 1853) is an Eifelian species. Kransia (Fatimaerhynchia?) aff. goldfussii from the Givetian of Bilveringsen is a separate species (larger, more transverse, more strongly ornamented), which is not described because of insufficient material. Kransia (Fatimaerhynchia) signata (Schnur, 1851) is present in the Middle Devonian of Jbel Issoumour, the middle Eifelian of the Eifel and the (upper?) Givetian of the Holy Cross Mountains

Cyclic ecological replacement of brachiopod assemblages in the top-Eifelian Dobruchna Brachiopod Shale Member (Skały Formation) of the Holy Cross Mountains (Poland)

The palaeoecology of fossiliferous shales, belonging to the upper part of the Dobruchna Brachiopod Shale Member (= set XIV) of the Skały Formation (northern Holy Cross Mountains), was studied quantitatively in a succession in the transient (1989) trench A, 5.6 m thick, near the village of Skały. The top-Eifelian strata, recording the carbonate crisis during the global Kačák Bioevent, are well known for having a particularly diverse brachiopod fauna. The four brachiopod assemblages, recognised herein, were mainly controlled by the evolving bottom-sediment properties of the outer carbonate ramp basin. Soft, unstable substrates were inhabited by the poorly-diversified Poloniproductus assemblage, associated with a distinctive, ‘incumbent’ set of largely semi-infaunal, generalist species. The pioneer community, as a result of progressive consolidation of bioclast-enriched sediment, evolved toward a more diverse biota. This consequent stabilisation of the substrate resulted in the progressive growth of crinoid thickets or bryozoan-dominated biostromes and patches, associated with rich, subordinate, sessile and vagile benthos. In this stage, diverse brachiopod assemblages were dominated by the pedunculate, eurytopic, ribbed spiriferide Eleutherokomma or specialized orthides (Aulacella, Costisorthis) in the Dobruchna Mbr, and by the expansive, large, free-lying orthotetide Xystostrophia in the overlying set XV of the Skały Fm The cyclic ecological replacement, with the characters of ecological succession in the final phase, was evidently stimulated by an irregular transition from soupy muds to a mosaic of bioclast-rich and firmer, biogenic sediments, within the cyclic pattern of distal tempestite sedimentation. The three episodes of variously reduced deposition rate, recorded in the more diverse benthos, culminated in the pioneer bryozoan/coral reef growth and abundance of epibionts, alternating with times of destructive storm activity and deposition from suspension clouds in the muddy habitats

Middle Devonian brachiopods from northern Maïder (eastern Anti-Atlas, Morocco)

Sixty brachiopod species are reported from the Taboumakhlouf Formation (upper Eifelian) and the Bou Dib Formation (upper Eifelian to Givetian) of Jbel Issoumour, northern Maïder, Anti-Atlas, Morocco, on the basis of collections made by Volker Ebbighausen. The stratigraphy is based on reports of co-occurring trilobite assemblages. The relatively diversified fauna pre-dates the Taghanic event and is dominated in terms of diversity by atrypides and rhynchonellides (11 species each); other frequent species include Poloniproductus varians, Aulacella prisca, Tyersella tetragona, Schizophoria schnuri, Athyris ex gr. concentrica, Yeothyris? sinuata, and Thomasaria simplex. Spinatrypa ennigaldinannae Halamski and Baliński sp. nov. from the upper Eifelian is characterised by a transverse shell, typically 16–18 mm wide with 19–22 ribs. Prodavidsonia ebbigahuseni Halamski and Baliński sp. nov. differs from other representatives of the genus in having nearly flat shells. Eressella coronata Halamski and Baliński, nom. nov. is proposed as a replacement name for the permanently invalid Rhynchonella coronata Kayser, 1871 (non R. coronata Moore, 1861). Thomasaria simplex is documented as being a particularly variable species (costation, tongue, interarea position), so its broad taxonomic treatment is favoured. The brachiopod fauna shows distinct Rhenish affinities (numerous species in common with the Eifel and the Holy Cross Mountains) like the coeval fauna from southern Maïder, described previously. The Middle Devonian brachiopod fauna from the whole Maïder (north, described here and south, described previously) totals 87 species