Revision Of Late Devonian (Famennian) And Some Early Carboniferous (Tournaisian) Crinoids And Blastoids From The Type Devonian Area Of North Devon

The crinoids and blastoids from the Pilton (Beds) Formation of the type Devonian of north Devonshire are revised. These fossils were monographed by the Rev. G. F. Whidborne in 1898, but have not been studied since that time. Recent studies on various groups of fossils from the Pilton and related rocks in North Devon confirm that the great majority of these fossils are Famennian, although three specimens from Fremington are probably Early Carboniferous (Tournaisian). We identify four blastoid taxa from a fauna that is sparse and poorly preserved; two spiraculates, one fissiculate, and one taxon unidentifiable at the ordinal level. Mesoblastus cf. M. crenulatus from the Gattendorfia Zone (Lower Carboniferous) near Fremington is the oldest known representative of this genus. The crinoid fauna is somewhat more diverse, but the preservation is equally poor. No changes are made in the flexible crinoids. Among camerate crinoids, one species is reassigned to Eumorphocrinus and one is retained in Actinocrinites. Specimens of some crinoids, such as Rhodocrinites and Megistocrinus, are so poorly preserved that certain identification was not possible. The hexacrinoid Adelocrinus, relegated to uncertainty for 150 years, is here shown to be a valid genus that is very similar to Arthroacantha, but not synonymous with it. Among the cladid crinoids, the dominant groups are those within the Superfamily Scytalocrinacea, which includes Bridgerocrinus, Sostronocrinus, and Scytalocrinus, all of which are placed in the new family Sostronocrinidae. One new species, Glossocrinus whidbornei, is named. Non‐pinnulate cladids, common in older Devonian rocks, do not occur. The fauna shows considerable similarity with faunas from eastern North America and Germany. It shows less resemblance to the extensive Famennian crinoid and blastoid fauna of north‐western China, despite some remarkable congruencies, especially the occurrence of very similar species of Actinocrinites in these widely separated areas.     

Famennian conodonts from the Hongguleleng Formation at the Bulongguoer stratotype section,western Junggar,Northwest China

The Hongguleleng Formation, the highest and most important Devonian marine carbonate horizon in western Junggar, contains an endemic shallow-water Icriodus–Polygnathus conodont fauna with rare palmatolepids and other genera. The conodont faunas from the Bulongguoer and the Wulankeshun sections are similar, with high abundance (about 40%) of endemic taxa (13 taxa), indicating isolation of the Junggar Basin during early Famennian. Non-endemic species in the faunas suggest that the Lower Member of the Hongguleleng Formation is assignable to the Pa. rhomboidea Zone to the Pa. marginifera marginifera Zone of early Famennian, not including the Frasnian–Famennian boundary. The Upper Member may be of late Famennian–early Tournaisian in age on the basis of our preliminary faunal analysis.     

A palaeospinacid shark from the Upper Triassic of south-west England

The fin spines of a new neoselachian shark are described from die Upper Triassic of Aust Cliff, Avon and Holwell, near Frome in Somerset. The spines are assigned to Palaeospinax rhaeticus sp. nov. This record adds to the known diversity of Upper Triassic marine vertebrates from Britain and extends the range of the palaeospinacid sharks into the Rhaetian.     

Spiriferide brachiopods from the Famennian (Late Devonian) Hongguleleng Formation of western Junggar,Xinjiang, northwestern China

Junggar is one of the most important areas in the study of the Upper Devonian and Lower Carboniferous in the Junggar-Hinggan Stratigraphic Region. Nevertheless, abundant benthic fossils await modern taxonomic studies. In this paper, six genera and eight species of Famennian spiriferide brachiopods are described from the Duguer Member and its equivalents of the Hongguleleng Formation in western Junggar, adding new data to the Rugaltarostrum Subassemblage of the “Palaeospirifer”–Megalopterorhynchus Brachiopod Assemblage of this area. Five previously recognized species within this subassemblage are revised, including: Cyrtospirifer junggarensis F.M. Zhang [now Ulbospirifer? junggarensis (F.M. Zhang)]; Tenticospirifer tenticulum transversus F.M. Zhang [now Cyrtospirifer transversus (F.M. Zhang)]; Tenticospirifer koketekensis F.M. Zhang [now Cyrtospirifer koketekensis (F.M. Zhang)]; Mucrospirifer quadratus F.M. Zhang (now “Mucrospirifer” quadratus F.M. Zhang); and Mucrospirifer bouchadi (Muir-Wood) (now Tylothyris cf. novamexicana Stainbrook). Three additional species, Cyrtiorina houi n. sp., Goungjunspirifer sinicus F.M. Zhang, and Cyrtospirifer procumbens Simorin in Litvinovich et al., are described. Ulbospirifer? junggarensis and Goungjunspirifer sinicus are characterized by a prismatic layer. Cyrtiorina houi shows a moderately high and triangular ventral interarea, with delthyrium covered by pseudodeltidium with a rounded foramen. Cyrtospirifer procumbens can be distinguished from other species of this genus by its shallow, clearly limited sulcus with prominent primary plications, and high ventral interarea. Cyrtospirifer transversus has an alate to subpentagonal outline. Cyrtospirifer koketekensis has rounded and distinct flank plications. The ventral delthyrium of “Mucrospirifer” quadratus is covered by a pseudodeltidium. Tylothyris cf. novamexicana develops an angular sulcus in cross-section. Comparisons with the coeval brachiopod faunas from various regions indicate that, biogeographically, western Junggar has a close relationship with the Tarbagatai Mountain Range, northeastern Kazakhstan, central Kazakhstan, and Karaganda Basin, and a certain affinity with North America.     

Large Tristichopteridae (Sarcopterygii, Tetrapodomorpha) from the Late Famennian Evieux Formation of Belgium

Remains of two large sarcopterygians are described from Famennian deposits in Belgium. One of them is referred to Eusthenodon wängsjöi Jarvik; it is the first occurrence of this genus in Belgium. The other, much larger one, appears to be a tristichopterid. It has a postspiracular; size and shape of the mandible similar to those of Platycephalichthys skuenicus and P. bischoffi ; snout and cheek patterns close to those of Eusthenodon ; unusual shape of the supratemporal resembling that of Hyneria , Mandageria and Platycephalichthys skuenicus ; and tooth histology quite similar to that of Eusthenodon and Platycephalichthys .     

New species of Antognathus (Conodonts) from the Famennian deposits of southern Kazakhstan

A new conodont species, Antognathus vjatsheslavi sp. nov., is described from the Famennian shallow-water carbonate deposits of the Bolshoi (Greater) Karatau Range in southern Kazakhstan.     

New bryozoans (Bryozoa) from the Upper Devonian (Lower Famennian) of the Kuznetsk Basin

New bryozoans from the Upper Devonian (Famennian) of the borderlands of the Kuznetsk Coal Basin are described: Orthopora tomensis sp. nov. and Minussina incrustata sp. nov.     

Late Devonian - Early Carboniferous vertebrate microremains from the Carnic Alps, northern Italy

Vertebrate microremains from the Late Devonian-Early Carboniferous of the Carnic Alps are predominantly chondrichthyan, with minor placoderm and actinopterygian remains. The faunas are sparse and, with very few exceptions, occur only in conodont-rich pelagic limestones (Pramosio Limestone) representative of the palmatolepid-bispathodid conodont biofacies. Phoebodont and jalodont chondrichthyans, also reflecting open-ocean environments, predominated during the Famennian, and eventually symmoriids seem to predominate during the Early Carboniferous. The presence of Siamodus in this assemblage gives a new locality for this genus known from few regions in the world and allows confirming its stratigraphical range (limpidus Zone) and its relation to deep-water environments. The Late Devonian vertebrate faunas are tropical and cosmopolitan, having much in common with coeval taxa from the North-Gondwanan margins and Asian terranes. Composition of the vertebrate faunas is consistent with the Carnic Alps terrane having occupied a position intermediate between Gondwana and Laurussia, as hypothesized by various authors, but because of sparsity of the taxa represented and the pronounced cosmopolitan nature of both the conodont and vertebrate faunas, the data are not compelling.     

Revision of Strunian crinoids and blastoids from Germany

In 1930W.E. Schmidt described all known crinoids from the German Early Carboniferous, including the Etroeungt beds of Germany, which are now judged to be latest Devonian (Famennian) in age. On a global basis, Famennian camerate crinoids generally show a closer relationship to succeeding Early Carboniferous faunas than they do to older Frasnian or Middle Devonian crinoids, which also is the case for the Strunian fauna. Holdovers from older Devonian faunas include, among others,Adelocrinus, a descendant of olderArthroacantha, in England and Germany, andPetaloblastus, which is one of the youngest genera of the blastoid family Hyperoblastidae. Precursors of younger Early Carboniferous groups include platycrinoids, primitive actinocrinoids, dichocrinoids, and the blastoid genusDoryblastus, which is one of the oldest members of the family Orbitremitidae. All of these groups, which became important parts of the Early Carboniferous crinoid and blastoid radiation, give Famennian crinoid faunas much more of an Early Carboniferous than a Devonian aspect. Rhipidocrinus schmidti n. sp. is erected for specimens that originally were reported from the Etroeungt asRhodocrinus uniarticulatus. We judge that there are currently four valid species assigned toRhipidocrinus: R. crenatus, R. perloricatus, R. praecursor, and our new species,R. schmidti. Hydriocrinus ratingensis Schmidt is reassigned to ?Sostronocrinus. We note thatSchmidt (1906), notJaekel (1906) as has been reported previously, is the author ofRhipidocrinus perloricatus. Owing to the poor preservation of the Etroeungt material, we regard the namePlatycrinites wunstorfi Schmidt 1930 to be a nomen nudum.     

Progressive drowning of carbonate platform in the Moravo-Silesian Basin (Czech Republic) before the Frasnian/Famennian event: facies,compositional variations and gamma-ray spectrometry

The Moravo-Silesian Basin (MSB; eastern Czech Republic and southern Poland) hosted an extensive shallow-water carbonate platform in the Middle Devonian to Frasnian interval. The platform drowned in a stepwise fashion from the Palmatolepis hassi to the Pa. linguiformis zone. Three types of drowning successions were revealed from conodont biostratigraphy, facies, microfacies and gamma-ray spectrometry data: (A) drowning to periplatform turbidite setting; (B) drowning to (hemi)pelagic seamount setting and (C) drowning associated with the stratigraphical gap. In the lower Pa. hassi zone, rapid subsidence caused the platform to drown locally along the N–S to NW–SE trending faults (type A drowning). In the upper Pa. rhenana to the Pa. linguiformis zone, the drowning accelerated in the western part of the MSB due to locally higher subsidence rates combined with the Late Frasnian biotic crisis (type B). In the southern part of the basin, the platform emerged shortly before the Frasnian/Famennian (F/F) boundary and drowned in the Early to Late Famennian (type C). The primary cause of drowning was differential subsidence at the Laurussian passive margin. Eustatic sea-level fluctuations, if any, contributed only to a minor extent to the Late Frasnian drowning, but were effective in type C drowning during the Famennian. The drowning boundaries are associated with increased contents of K and Th, reflecting the deceleration of carbonate production. Uranium contents display isolated peaks that roughly correlate with the drowning boundaries or the stratigraphic gaps associated with the F/F boundary. The uranium contents are considered to reflect local depositional conditions and are not suitable for stratigraphic correlation. On the other hand, from the K and Th contents, we can infer Late Frasnian sea-level fluctuations with duration on the order of 1 Myr. These cyclic variations in K and Th contents proved to be useful in platform-to-basin stratigraphic correlation.     

Microfossil assemblage from the Late of Middle Carboniferous in Western Shaan-Gan-Ning Basin,Northwest China

In this paper, some results of the study on the sporepollen of the Yanghugou Formation in the western Shaan-Gan-Ning (Ordos) Basin of Northwest China axe reported. Plenty of well preserved microfossil, which 136 types belong to 62 microspore genera and one megaspore genus, including 2 new genera , 13 new species, I Acritarch (Chamosphaera pseudozonatus gen. et sp. nov.), from 8 bore-holes and outcrop have been discribed. In generally, the microfiora of the Yanghugou Formation is similar to the Taiyuan Formation (Upper Carboniferous). According to the spore-pollen assemblage of Yanghugou Formation may correlate with those in the Middle Carboniferous of Great Britain, Belgium the north of France, German and North America. Besides, the assemblage are similar to Middle Carboniferous of Nortth Shandong and Hengshanbu of Ningxia in the microfossil assemblage. The geological age of the beds is considered to Late of Middle Carboniferous.     

Phyllocarid remains (Malacostraca, Crustacea) from the basal Famennian (Late Devonian) of the Montagne Noire (Southern France)

From the early Famennian of the Montagne Noire 19 different morphotypes of probably phyllocarid (Crustacea) affinities are described. Apart from formerly unknown enamel-like structures that veil the uppermost tips of the denticles on most of the gnathal lobe morphs, the stratigraphic implications concerning extinction behaviour across the Kellwasser mass extinction event and during early Famennian diversification are discussed. In addition, phyllocarids in the Famennian seem to form a useful stratigraphic tool for biostratigraphical correlation. Therefore, three basal Famennian phyllocarid assemblage zones are distinguished.      

Evidence for the teleosaurid crocodylomorph genus Machimosaurus in the Kimmeridge Clay Formation (Late Jurassic) of England

We report the only definite specimen of the teleosaurid crocodylomorph genus Machimosaurus from the Kimmeridge Clay Formation of England. This specimen (an isolated tooth) is now the only evidence of Machimosaurus in the Kimmeridge Clay Formation because a large skull and mandible, previously considered to be of Machimosaurus mosae, was recently shown to pertain to a metriorhynchid crocodylomorph. The tooth described herein was originally figured in 1884 as a tooth crown from a metriorhynchid crocodylomorph. However, its conical shape, blunt apex and distinctive enamel ornamentation are characteristic of the teleosaurid genus Machimosaurus. That Machimosaurus, and teleosaurids in general, were so rare in the Kimmeridge Clay Formation suggests that these marine crocodylomorphs did not commonly use this seaway. Their rarity is in contrast to contemporaneous deposits from continental Europe where teleosaurid remains, including Machimosaurus, are far more common. These continental deposits were deposited in shallow-marine/brackish ecosystems, suggesting that teleosaurids were largely restricted to coastal marine environments.     

Epizoans immured in the heterocoral Oligophylloides maroccanus Weyer, 2017: a unique record from the Famennian (Upper Devonian) of Morocco

Exceptionally well-preserved proximal parts of colonies of the late Famennian heterocoral Oligophylloides maroccanus Weyer, 2017 with immured epizoans are described here from the Jebel Bou Ifarherioun ridge of the eastern Anti-Atlas, Morocco. This is the first evidence of unique syn vivo interactions between a heterocoral and numerous epizoans, that is the colonial tabulate corals Zemmourella? sp. and Aulopora? sp.; solitary rugose corals Czarnockia? sp. and Gorizdronia? sp.; and other juvenile, undeterminable solitary rugosans, crinoids, as well as microbial structures. Detailed analysis of sectioned specimens allowed mutual interactions to be traced during growth of the host and infesting encrusting taxa. The studied associations show that the epizoans must have settled on the proximal parts of Oligophylloides in places devoid of soft tissue. The encrusted proximal portions of the colonies show that soft tissue of the heterocoral could have retracted and expanded again, fouling and immuring dead epizoans. The process of bioimmuration is perfectly marked by thin layers of microbial encrustations developing on the epibiont skeletons prior to their overgrowth by the skeleton of the heterocoral. The studied encrustations seem to be widespread, but the association provided the epizoans with additional substrate for encrustation, as well as an elevated position above the seafloor, beneficial for access to nutrients. We suggest that the host bioimmured the encrusters after their death, because of noticeable microbial encrustations and veneers of sediment, a lack of malformations, relatively rapid growth and aggressive activity of epizoans.     

A Late Devonian plant assemblage from the Avon Gorge, west England: taxonomic, phylogenetic and stratigraphic implications

Plant fossils from the Avon Gorge originally identified as Rhacophyton sp. have been subjected to a detailed morphological study incorporating examination of both previously known material and new specimens. A single taxon, Chlidanophylon dublinensis, dominates the assemblage accounting for over 90% of the fossils encountered. Other plant organs identified include dispersed acupulate preovules and five less frequently occurring organs of which four are of unknown affinities; the leaf genus Platyphyllum, Alicomopleris sp., two kinds of novel and frequendy dichotomizing branching structures and the spermatophyte synangium Telangiopsis. Possible whole plant relationships between the components of the fossil assemblage are discussed and the stratigraphic, systematic and evolutionary position of the component taxa are considered.     

Largest known specimen of the genus Dakosaurus (Metriorhynchidae: Geosaurini) from the Kimmeridge Clay Formation (Late Jurassic) of England,and an overview of Dakosaurus specimens discovered from this formation (including reworked specimens from the Woburn Sands Formation)

We report the largest known British specimen of the metriorhynchid crocodylomorph genus Dakosaurus discovered offshore from Chesil Beach, Dorset, England (Kimmeridge Clay Formation). This specimen is large toothed, which has extreme enamel spalling on the labial surface, enlarged carinae (‘carinal flanges’), carinal wear, macroziphodont denticles, and the crown retains much of its labiolingual width along most of its apicobasal length. This suite of morphologies is unique to Dakosaurus. All known Kimmeridge Clay Formation Dakosaurus specimens are isolated tooth crowns. A skull previously referred to Dakosaurus lacks all the cranial apomorphies of D. maximus and D. andiniensis, and cannot be referred to this genus. Furthermore, the vast majority of putative Dakosaurus tooth crowns from the ‘Potton Sands’ ( = Woburn Sands Formation) do indeed represent Dakosaurus (as well as two Plesiosuchus specimens), and they most likely originate from the Kimmeridge Clay Formation.