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SEM micrographs of Concinnithyris subundata from near Novachene, Sanadinovo Formation (Lower Cenomanian). A, B, longitudinal section at centre of ventral valve (ZPAL Bp.52/7); with A representing the entire shell thickness; external surface on the right, primary layer in the lower right-hand corner. On the right, two layers of secondary fibres interlayered with tertiary prisms building the main thickness of the shell, two thinner layers of secondary fibres are seen on the left; B represents a portion of shell, close to the external surface. Recrystallised primary layer on the right, followed by two layers of secondary fibres and two of tertiary fibres. Two punctae filled with recrystallised calcite. C, D, cross sections of the umbonal part (ZPAL Bp.52/8), with C representing a ventral valve, entire shell thickness, penetrated by punctae. Lateral portion of ventral valve to the left; note increase in thickness of the tertiary sublayers towards the shell centre; D shows the dorsal umbo, cardinal process (c.p.) and incipient hinge plates (h.p.). E, F, transverse sections of the entire shell showing secondary and tertiary layers, visible modifications of fibres near punctae (ZPAL Bp.52/9). Scale bars represent 200 m m (A, C, D), 100 m m (B, E) and 50 m m (F).
Source publication
Brachiopod faunas from the Early Cenomanian Sanadinovo Formation in northern Bulgaria comprise seven species in five genera, namely Cyclothyris sp., Concinnithyris subundata (J. Sowerby), Terebratulina imbricata Owen, T. etheridgei Owen, Terebratulina sp., Kingena concinna Owen and Modestella geinitzi (Schloenbach). With the exception of Cyclothyri...
Contexts in source publication
Context 1
... ultrastructure. Two sections were studied under SEM: one longitudinal through the middle of the ventral valve and a second transverse through the umbo (Fig. 5). (Table ...
Context 2
... layer thickness increases from the lateral to the central part of the shell in transverse section. Secondary layer fibres are usually subparallel to the shell long axis. In cross sections they have an anvillike shape. Density of punctae, which penetrate the whole thickness of the shell, is 100e150/mm 2 in the cross section of the ventral umbo (Fig. ...
Context 3
... large size (L max , 39.4 mm; L min , 25.4 mm; Owen, 1988, p. 134), while the material studied here is much smaller. The posterior part of the specimen sectioned for the present study (Fig. 4) is poorly preserved and crural bases are not clearly seen. However, the rest is entirely similar to sections of C. subundata illustrated by Owen (1988, fig. 25), especially with regard to the inwardly concave, descending branches and the wide transverse band with a shallow sulcus ...
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... For fossil specimens, destructive techniques such as transverse serial sections have been the most widely used approach to begin to reconstruct the complex loop morphology in three dimensions (e.g. [79][80][81][82]). It is possible to use this technique to create 3D models by cutting a fossil into very thin slices perpendicular to the plane of symmetry to produce successive 2D images and then stacking them to generate a 3D reconstruction [83]. ...
Species of terebratulide brachiopods have been largely characterized qualitatively on the basis of morphology. Furthermore, species-level morphological variability has rarely been analyzed within a quantitative framework. The objective of our research is to quantify morphological variation to test the validity of extant named species of terebratulide brachiopods, focusing on the lophophore-supporting structures—the “long loops.” Long loops are the most distinctive and complex morphological feature in terebratellidine brachiopods and are considered to be phylogenetically and taxonomically informative. We studied eight species with problematic species identities in three genera distributed in the North Pacific: Laqueus, Terebratalia, and Dallinella. Given how geometrically complex long loops are, we generated 3D models from computed tomography (CT) scans of specimens of these eight species and analyzed them using 3D geometric morphometrics. Our goal was to determine ranges of variation and to test whether species are clearly distinguishable from one another in morphospace and statistically. Previous studies have suggested that some species might be overly split and are indistinguishable. Our results show that these extant species of terebratellidines can be reliably distinguished on the basis of quantitative loop morphometrics. Using 3D geometric morphometric methods, we demonstrate the utility of CT beyond purely descriptive imaging purposes in testing the morphometric validity of named species. It is crucial to treat species described and named from qualitative morphology as working hypotheses to be tested; many macroevolutionary studies depend upon the accurate assessment of species in order to identify and seek to explain macroevolutionary patterns. Our results provide quantitative documentation of the distinction of these species and thus engender greater confidence in their use to characterize macroevolutionary patterns among extant terebratellidine brachiopods. These methods, however, require further testing in extinct terebratellidines, which only rarely preserve the delicate long loop in three dimensions. In addition, molecular analyses of extant terebratellidines will test the species delimitations supported by the morphometric analyses presented in this study. [Species determination; morphological variability; 3D geometric morphometrics; terebratulide brachiopods; long loops.]
... For fossil specimens, destructive techniques such as transverse serial sections have been the most widely used approach to begin to reconstruct the complex loop morphology in three dimensions (e.g. [79][80][81][82]). It is possible to use this technique to create 3D models by cutting a fossil into very thin slices perpendicular to the plane of symmetry to produce successive 2D images and then stacking them to generate a 3D reconstruction [83]. ...
Species of terebratulide brachiopods have been largely characterized qualitatively on the basis of morphology. Furthermore, species-level morphological variability has rarely been analyzed within a quantitative framework. The objective of our research is to quantify morphological variation to test the validity of extant named species of terebratulide brachiopods, focusing on the lophophore-supporting structures-the "long loops." Long loops are the most distinctive and complex morphological feature in terebratellidine brachiopods and are considered to be phylogenetically and taxonomically informative. We studied eight species with problematic species identities in three genera distributed in the North Pacific: Laqueus, Terebratalia, and Dallinella. Given how geometrically complex long loops are, we generated 3D models from computed tomography (CT) scans of specimens of these eight species and analyzed them using 3D geometric morphometrics. Our goal was to determine ranges of variation and to test whether species are clearly distinguishable from one another in mor-phospace and statistically. Previous studies have suggested that some species might be overly split and are indistinguishable. Our results show that these extant species of terebra-tellidines can be reliably distinguished on the basis of quantitative loop morphometrics. Using 3D geometric morphometric methods, we demonstrate the utility of CT beyond purely descriptive imaging purposes in testing the morphometric validity of named species. It is crucial to treat species described and named from qualitative morphology as working hypotheses to be tested; many macroevolutionary studies depend upon the accurate assessment of species in order to identify and seek to explain macroevolutionary patterns. Our results provide quantitative documentation of the distinction of these species and thus engender greater confidence in their use to characterize macroevolutionary patterns among extant ter-ebratellidine brachiopods. These methods, however, require further testing in extinct tereb-ratellidines, which only rarely preserve the delicate long loop in three dimensions. In addition, molecular analyses of extant terebratellidines will test the species delimitations supported by the morphometric analyses presented in this study. [Species determination; morphological variability; 3D geometric morphometrics; terebratulide brachiopods; long loops.] PLOS ONE | https://doi.org/10.1371/journal.pone.
... Age and distribution: This species also occurs in the lower to middle Cenomanian sediments of the Dobrevacuka locality near Beloslav in Bulgaria [4] and from Albian? -lower Cenomanian sediments of Baghin region, Iran [2]. This species is recovered from cenomanian sediment of Vezk section, Yasuj, Iran. ...
... Brachiopods are facies sensitive and their distribution is controlled by facies change. Rhynchonelloids are rare or absent in marly facies, while terebratuloids prefer marly sediments, of which the present paper provides another example [4]. The Early Cenomanian was a period during which numerous species originated; among these are such taxa as Concinnithyris subundata and Kingena arenosa described herein. ...
Brachiopod faunas from the Aptian- Cenomanian Vezk section in southwestern Iran comprise ten species in six genera, namely Sellithyris cenomanensis, Sellithyris tornacensis, Sellithyris phaseolina, Phaseolina phaseolina, Tropeothyris sp., Concinnithyris subundata, Kingena arenosa, Cyclothyris difformis, Cyclothyris sp. and Cyclothyris compressa. All species are recorded for the first time from the lower Cretaceous of Vezk section (South of Yasuj). These deposits are composed of an alternation of green marls and thin layers of yellow shaly or sandy limestone, which overlain by thick bedded black limestone. The thickness of these deposits are 74 meters, which covers the Jurassic sediments, while its upper boundary ends with erosion surface that covered by Neogene deposits. These deposits consist of different fossil groups such as brachiopods, echinoids, corals, gastropods and orbitolinids that confirm the Aptian- Cenomanian ages for these sediments. The fauna assemblages suggest at shallow and suitable environment prevailed during the deposition of the strata.
... The small size is an adaptation quite common in brachiopods through time. Some limited examples confirm the fact that such small species were present from the Palaeozoic (Mottequin et al., 2015) through the Mesozoic (Surlyk, 1972;Bitner & Pisera,1979;Simon, 2000;Bitner & Motchurova-Dekova, 2005) and into the Tertiary (Bitner & Dulai, 2008). This led us to erect a new species placed in a new genus described below as Lenticellaria gregoryi gen. ...
Two new kraussinid brachiopod genera, namely Lenticellaria gen. nov. and Hillerella gen. nov. are described from Pacific waters in the sub-equatorial zone in the Indonesian Archipelago, from Indian Ocean waters in Madagascar and from Red Sea waters in Egypt (Gulf of Aqaba) and Sudan. This fills the equatorial gap in the distribution of the superfamily Kraussinoidea, known from higher latitudes in both hemispheres. The micromorphic new material described is an excellent example of homeomorphy in brachiopods. It also provides new information on the distribution of the genus Megerlia sensu stricto and illustrates subtle variations in the evolutionary process of the reduced brachidium in Kraussinoidea.
... Sedimentary environment of facies association D euryhaline organisms (such as brachiopod, red algae, bryozoans, echinoid, and some bivalves) indicate deposition in the open marine environments (Flugel 2010;Bitner and M-Dekova 2005;Bachmann and Hirsch 2006;Holcova and Zagorsek 2008;Carcel et al. 2010;Chen et al. 2011;Saber 2012). In addition, high content of limy mud reflects rather low energy conditions of sedimentation (Adachi et al. 2004). ...
... In some recent papers published after the appearance of the revised Treatise, serial sections of Mesozoic brachiopods were presented in the traditional manner with the ventral valve up (e.g. Pálfy 2003;Siblík 2003;García Joral & Goy 2004;Sulser 2004;Bitner & Motchurova-Dekova 2005;Bujtor 2006;Radulovi ç et al. 2006;Andrade 2006;Motchurova-Dekova & Simon 2007;Radulovi ç et al. 2007 and others). Thus, the future will show which orientation of the valves in post-Palaeozoic brachiopods will be established in practice. ...
... Sowerby, 1813) Remarks. This species (not illustrated here) is known from the Cenomanian of England, northern Germany and northern Bulgaria (Bitner and Motchurova-Dekova, 2005). In England, it is particularly typical of beds above the primus Event. ...
... Cenomanian marly limestone facies in England and France, but is also known from greensands such as the Essen and Quedlinburg greensands of northern Germany and has recently been recorded from northern Bulgaria (Bitner and Motchurova-Dekova, 2005). It is a fairly abundant brachiopod of the primus Event (and also occurs in the arlesiensis Bed at Wunstorf), but is difficult to distinguish from juveniles of Kingena concinna, which explains why it is often confused with that species. ...
... Kingena concinna is particularly common in the primus Bed in southern England, together with M. geinitzi and Grasirhynchia martini. There is also a record from the Lower Cenomanian of northern Bulgaria (Bitner and Motchurova-Dekova, 2005). ...
A systematic account of the fauna from the early Middle Cenomanian Praeactinocamax primus Event, a 50–60-cm-thick marl bed, at the type locality, Wunstorf quarry, to the west of Hannover (northern Germany), is given. Numerous invertebrate taxa (over 50 in total) have been collected, including two species of belemnites, ten ammonites, at least 12 bivalves, a single scaphopod, five gastropods, at least eight brachiopods, two solitary corals, a single hydrozoan, four echinoids, and ten polychaetes. The benthic community of the primus Event clearly represents a soft-bottom fauna, with hard-bottom elements limited to secondary hard substrates. Most of the macrobenthic elements constitute suspension feeders; shallow-infaunal deposit feeders, grazers and microcarnivores occur as well, while deeper infaunal elements are largely missing. The nekton is represented by fish remains, belemnites, and planispiral and heteromorph ammonites with inferred nektobenthic modes of life. Both biofacies (absence of photic elements) and sedimentological evidence (fine-grained fabric, preservation of delicate faunal elements) suggest that deposition of the primus Event at the type locality occurred in a low-energy setting below the (eu-)photic zone and storm wave base in water depths of ca. 50–100 m. The cyclic and correlative nature of the precession-forced marl-limestone couplets of the interval containing the primus Event and the absence of sedimentological evidence for significant redeposition rules out “snapshot preservation” by obrution. Nor is the faunal richness of the primus Event related to time-averaging, because the bed accumulated with sedimentation rates of ca. 50 m/myr. The abundance of suspension- and deposit-feeding biota, however, indicates enhanced fluxes of organic carbon to the seafloor, probably related to high surface-water productivity. The formation of the primus Event was also linked to transgressive depositional conditions after a pronounced sea-level lowstand across the Lower/Middle Cenomanian boundary. It should be noted that correlation of sections across northwest Europe clearly shows that the initial transgressive onlap onto the basin margins following the lowstand started considerably earlier than the primus Event, at the junction of marl-limestone couplets B40/B41 in the Anglo-Paris Basin cyclostratigraphic scheme. The primus Event (marl bed of couplet C1) thus represents a second transgressive pulse of a high-frequency (100 kyr short eccentricity) cycle within the transgressive systems tract (TST) of a third-order depositional sequence. “Pulse faunas” of northerly affinity (such as the Boreal belemnite P. primus) and published oxygen stable isotope records suggest a cool-water incursion during the “primus transgression”. These special oceanographic conditions (sea-level rise, incursion of cool waters, high primary productivity, ample food supplies, limited physical disturbance) resulted in a diverse benthic (and nektobenthic) faunal community in the primus Event.
The latest Albian (Vraconian) brachiopod fauna from Enisala, in North Dobrogea, includes representatives of rhynchonellids and terebratulids. The rhynchonellids are scarce, representing two families, Cyclothyrididae and Tetrarhynchiidae. The Cyclothyrididae with the subfamily Cyclothyridinae, and the Tetrarhynchiidae with the subfamily Cretirhynchiinae, are represented by rare specimens of ? Cyclothyris sp. and Burrirhynchiidae cf. sigma (Schloenbach, 1867), respectively. The terebratulids are very abundant and include representatives of several families, as follows: Sellithyrididae, Capillithyrididae, Cancellothyrididae and Terebrataliidae. The Sellithyrididae, which make up the bulk of the assemblage, are represented by two subfamilies: Sellithyridinae with Sellithyris upwarnesis (Walker, 1870), Boubeithyris boubei (d'Archiac, 1847) and Ovatathyris cf. potternensis Owen, 1988, and Nerthebrochinae with Harmatosia crassa (d'Archiac, 1847). The Capillithyrididae are represented by the subfamily Capillithyridinae with Capillithyris capillata (d'Archiac, 1847). The Cancellothyrididae are represented by the subfamily Cancellothyridinae with numerous specimens of Terebratulina protostriatula Owen, 1988. The Terebrataliidae are represented by the subfamily Gemmarculinae with scarce specimens of Gemmarcula canaliculata (Roemer, 1840) and Gemmarcula sp. The abundance and diversity of the terebratulids in the brachiopod assemblage from Enisala was related to favourable environmental conditions connected with the onset of the marine transgression on North Dobrogea during the latest Albian. There is a marked stratigraphic lag with some species which in North Dobrogea occur in the latest Albian appearing in the Early Cenomanian in Central and Western Europe. This suggests that North Dobrogea was located on the main route of the westward migration of the mid-Cretaceous brachiopod faunas.
The Guri Member is a limestone interval at the base of the calcareous marls of the Mishan Formation. It is the youngest hydrocarbon reservoir of the southeast part of the Zagros sedimentary basin. This Member overlaid siliciclastic rocks of Razak Formation and is overlain by green and gray marls of the Mishan Formation. In order to consider the paleoecology and paleoenvironments of the Lower–Middle Miocene (Guri Member), we have studied biostratigraphy and sequence stratigraphy of the Guri Member based on foraminifer and microfacies in two stratigraphic sections including Dorahi–Homag and Chahestan. A total of 33 genera and 56 species of benthic and planktonic foraminifera were identified in two studied stratigraphic sections. Benthic and planktonic foraminifera demonstrate Aquitanian to Langhian age (Early–Middle Miocene) for this Member at the study area. Studied interval has deposited in four facies association including supratidal, lagoon, coral reef, and open sea on a carbonate ramp. Carbonate rocks of the Guri Member have precipitated in two and three depositional sequences at Chahestan and Dorahi–Homag sections, respectively. Sedimentation of marine carbonates of the Guri Member on siliciclastic deposits reflects a major transgression of sea level at Lower to Middle Miocene that led to creating a new sea in the Zagros basin at that age. Increasing siliciclastic influx along with a sea level fall finally caused burying of the carbonate ramp. Except for the beginning of sedimentation of carbonate at the base of both stratigraphic sections (depositional sequence 1), most of the system tracts are not matched to global sea level curve that reflect local effects of the basin. Distribution of foraminifera suggests precipitation in tropical to subtropical in mesotrophic to oligotrophic and eutrophic to oligotrophic conditions. Based on large benthic foraminifera (porcelaneous large benthic foraminifera and hyaline larger benthic foraminifera), water temperature average was determined between 25 and 30 °C that was confirmed by analyzing oxygen and carbon stable isotopes. Finally, we have utilized achieved data to reconstruction and modeling of paleoecology, paleoenvironments, and sea level changes in the southeast part of the Zagros basin.
