Brachiopod Fauna Research Articles

Kungurian (Cisuralian/Early Permian) brachiopods from the Snapper Point Formation, southern Sydney Basin, southeastern Australia

Elements of a high-latitude (∼60–70°S) and low-diversity early Kungurian (Cisuralian/Early Permian) brachiopod fauna have been sporadically reported from the sandstone-dominated Snapper Point Formation (SPF) in the southern Sydney Basin of southeastern Australia for more than a half-century, but a detailed description of this fauna is not yet available. In this paper we describe 12 brachiopod species and an indeterminate ingelarellid from the SPF, including one new species (Tasmanospirifer jervisbayensis sp. nov. Waterhouse & Lee). Though this brachiopod fauna is evidently associated with an interglacial stratigraphic interval, its taxonomic characteristics overall resemble those from stratigraphically bounding glacial intervals. This association is interpreted to indicate persistence and the strong endemic nature of the Permian Eastern Australian biogeographic province in high-latitude eastern Gondwana, regardless of glacial/interglacial climate states during the Cisuralian. Biostratigraphically, the SPF brachiopod fauna is divisible into two distinctive stratigraphic assemblages: the Notospirifer cf. triplicata–Simplicisulcus sp. Assemblage in the lower part of the formation and the Johndearia brevis–Sulciplica transversa Assemblage in the upper part, each distinguished by a set of unique species. Sangmin Lee [sangminlee76@gmail.com] and G. R. Shi [guang@uow.edu.au] School of Earth, Atmospheric and Life Sciences, University of Wollongong Faculty of Science Medicine and Health, Northfields Avenue, Wollongong, NSW 2522, Australia Bruce Runnegar [runnegar@ucla.edu] Earth, Planetary and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095-1567, USA J. B. Waterhouse [permia@xtra.co.nz] Oamaru, Oamaru, New Zealand.

Pennsylvanian brachiopod faunas from the El Imperial Formation (San Rafael Basin) of central-western Argentina

While some Upper Paleozoic basins in central-western Argentina have been extensively studied, others have poorly understood biostratigraphy. The current biozone heterogeneity between basins could be an artefact of incompletely sampled invertebrate fossil assemblages preventing precise correlations. Here, we therefore provide a taxonomic assessment of brachiopods recovered from fossil-bearing beds of the El Imperial Formation at Arroyo del Imperial, Quebrada de La Horqueta, and Cañón del Atuel. Two distinct biozones are identified: (1) a conspicuous Moscovian Tivertonia jachalensis–Streptorhynchus inaequiornatus Biozone (TS) from the Cañón del Atuel section; (2) a new early late Bashkirian Saltospirifer guevarai–Pericospira sanjuanensis Biozone (SP) from the Arroyo del Imperial and Quebrada de La Horqueta sections. The TS assemblage includes Argentiella stappenbecki, Oehlertella annae, Orbiculoidea saltensis, Coolkilella aredesi, Calytrixia piersoni, Costatumulus sp. and Septosyringothyris? sp. The SP assemblage comprises cf. Buxtonia riojana, Streptorhynchus inaequiornatus, cf. Septosyringothyris (Precosyringothyris) feruglioi, cf. Septosyringothyris (Precosyringothyris) jaguelensis, ?Spiriferellina sp., Saltospirifer guevarai and cf. Pericospira sanjuanensis. The El Imperial Formation brachiopod biozones provide a basis for accurate biocorrelation between regional lithostratigraphical units, and clarify the Upper Paleozoic biochronostratigraphical scheme for central-western Argentina during the Pennsylvanian. Cristian Adrián Pardo [pardocr22@gmail.com], Centro de Investigación Esquel de Montaña y Estepa Patagónica (CIEMEP) CONICET-UNPSJB, Roca 780, Esquel (U9200), Chubut, Argentina. Laboratorio de Investigaciones en Evolución y Biodiversidad (LIEB), Facultad de Ciencias Naturales y Ciencias de la Salud (FCNyCS), Sede Esquel, Edificio de Aulas, km 16.5, Esquel, Chubut, U9200, Argentina; César Augusto Taboada [ctaboada@mef.org.ar], Museo Paleontológico Egidio Feruglio (MEF)-CONICET, Avenida Fontana N°140, Trelew, Chubut, U9100GYO, Argentina; Arturo César Taboada [taboadaart@gmail.com], Centro de Investigación Esquel de Montaña y Estepa Patagónica (CIEMEP) CONICET-UNPSJB, Roca 780, Esquel (U9200), Chubut, Argentina. Laboratorio de Investigaciones en Evolución y Biodiversidad (LIEB), Facultad de Ciencias Naturales y Ciencias de la Salud (FCNyCS), Sede Esquel, Edificio de Aulas, km 16.5, Esquel, Chubut, U9200, Argentina; María Alejandra Pagani [apagani@mef.org.ar], Museo Paleontológico Egidio Feruglio (MEF)-CONICET, Avenida Fontana N°140, Trelew, Chubut, U9100GYO, Argentina.

New records and descriptions of recent Australian brachiopods (Terebratulida, Dallinidae and Aulocothyropsidae; and Rhynchonellida, Frieleiidae)

The recent brachiopod fauna of Australia remains poorly understood with several species lacking upto-date descriptions, and with many unidentified or misidentified specimens in museum collections. A large collection of brachiopods housed at the Tasmanian Museum and Art Gallery was recently examined to allow the re-description of two Australian endemic Dallinid brachiopods, Jaffaia jaffaensis and Campages furcifera, and identify new species and species occurrences. Furthermore, the large number of specimens allowed ecological aspects to be explored. As a result, the morphology and variation of C. furcifera and J. jaffaensis were clarified and expanded, a new deep-sea Dallinid species, Dallina tasmaniaensis, sp. nov. was described, the first occurrence of this genus from Australia, and the deep-sea Aulocothyropsid species Fallax neocaledonensis and Rhynchonellid Neorhynchia strebeli were also recorded from Australia for the first time. Jaffaia was revealed to be far more alike Nipponithyris than previously appreciated. The morphometric relationships of the three Dallinid species were found to differ significantly, with the attachment substrata and epibiota particularly prominent and diverse for J. jaffaensis and C. furcifera. This research facilitates the improved identification of Australian brachiopods, significantly increases understanding of variation within local species, and highlights the underappreciated biodiversity of deep-sea brachiopods in Australian waters.

RECENT BRACHIOPODS FROM SOUTH ATLANTIC OCEAN: FIRST OCCURRENCE OF THE LINGULIDAE AND ITS BIOGEOGRAPHIC IMPLICATIONS

The brachiopod fauna of the South Atlantic is significantly abundant and appears to be predominantly composed of cosmopolitan species. However, until now there was no record of inarticulate brachiopods of the Family Lingulidae in this region. The present study describes the first occurrence of lingulid brachiopods in the South Atlantic. Seven specimens were collected on the continental shelf of the Maranhão state, Northeastern Brazil, Western South Atlantic. The individuals were identified as belonging to the genus Lingula. Although brachiopods have great dispersion capability durintg their larval phase, the hypothesis that these specimens arrived on the Brazilian coast as a result of human activities cannot be ruled out.
 Keywords: Lingula, subfilo Linguliformea, “Inarticulata”, inarticulate brachiopods, Brazil.

UPPER CISURALIAN-LOWER GUADALUPIAN BRACHIOPODS FROM THE QARARI UNIT, BATAIN PLAIN, NORTHEAST OMAN: SYSTEMATICS, PALAEOECOLOGY AND CORRELATION

Permian brachiopods from Oman are well-known as valuable tools for correlation and palaeobiogeographical and palaeoclimatic reconstructions. Here, we describe a new brachiopod fauna from the Qarari Unit of the allochthonous Batain Group in northeast Oman. Brachiopods were collected from four localities: Wadi Khawr al Jaramah (WKJ), Jebel Qarari (JQ1), Jebel X (JX3) and Shiya (SH11). The age of the fossiliferous localities is wellconstrained to the late Kungurian-early Roadian by conodonts and fusulines, in agreement with the age suggested by the brachiopod ranges.The brachiopod fauna consists of 339 specimens belonging to 68 species of 8 orders, among which five species are here identified as new. Based on the taphonomic attributes and the analysis of the brachiopod life-styles, the assemblages from the Qarari Unit are interpreted as life assemblages thriving on varied substrates, with limited post-mortem exposure on the sea floor and rapid burial at depths around the storm wave base.Based on the generally high biodiversity indices (Shannon-Wiener and Margalef indices), the Qarari brachiopod fauna can be considered a biodiversity hotspot, only comparable, in term of biodiversity, to the coeval faunas from West Texas and South China. However, palaeobiogeographical affinities of the Qarari brachiopods with these faunas are scanty, as well as the affinities with coeval faunas from the northern Gondwana margin and the Cimmerian and Cathaysian blocks, except for some similarities with the upper Kungurian brachiopods of Myanmar. This may be explained by the fact that the Qarari succession was deposited in the Madagascan arm of Neo-Tethys, and thus rather isolated from the main Gondwanan margin.

Wuchiapingian (Lopingian, Late Permian) brachiopod fauna from Guangdong Province, southeastern China: systematics and contribution to the Lopingian recovery – CORRIGENDUM

Wuchiapingian (Lopingian, Late Permian) brachiopod fauna from Guangdong Province, southeastern China: systematics and contribution to the Lopingian recovery – CORRIGENDUM

Wuchiapingian (Lopingian, late Permian) brachiopod fauna from Guangdong Province, southeastern China: systematics and contribution to the Lopingian recovery

AbstractA diverse Wuchiapingian brachiopod fauna, which contains 57 species in 28 genera, is described from the Shuizhutang Formation at the Liannan section, Guangdong province, southeastern China. Four new species Tyloplecta liannanensis n. sp., Linoproductus huananensis n. sp., Araxathyris minor n. sp., and Permophricodothyris flata n. sp. are proposed. From well-preserved Liannan specimens, characteristics of the shell microstructures in Permianella are revised, and different morphologies of muscle scars in Permophricodothyris are distinctly shown. Until now, only several Wuchiapingian brachiopod faunas have been found in South China. Compared with these faunas, the Liannan fauna shows much higher α diversity and is more like faunas from southeastern China than those from the Yangtze area in faunal composition. The Liannan fauna is dominated with Neochonetes, Transennatia, Orthothetina, Permophricodothyris, and Cathaysia, which are normally larger and more strongly ornamented than their Changhsingian counterparts. The Wuchiapingian brachiopods in South China are represented mainly by the Douling fauna and Shuizhutang fauna. The Douling fauna has relatively low diversity and presents the survival stage after the Guadalupian–Lopingian boundary crisis. The Shuizhutang fauna has a much higher diversity and more key Changhsingian taxa and shows a rapid radiation stage. Faunal compositions of the two faunas indicate that the initial recovery of brachiopods occurred mainly at the genus level followed by a more rapid radiation at both genus and species levels.UUID: http://zoobank.org/474cd988-6ec3-4d16-b045-f84d5fe3fb66

Callovian (Middle Jurassic) Sphriganaria (Brachiopoda) from the Jordan Valley (Middle East)

ABSTRACT Middle Jurassic terebratulide brachiopods from the Jordan Valley are herein described and a new taxon is added to the previous faunal list. The Callovian rocks (Mughanniyya Formation) of the Tel el Dhahab section have yielded the following terebratulide taxa: Sphriganaria capax, S. costata, S. costellata, S. curtirostra, S. expansa, S. irregularis, S. subcircularis, S. nasuta, S. sp. 1, and S.? sp. 2. A new species Sphriganaria anyamiae sp. nov. is formally described herein. Internal characters of Sphriganaria costata, S. expansa, and S. nosuta have been studied. On the basis of shell microstructure, crural bases, outer and inner hinge plates were differentiated and defined for the first time in the genus Sphriganaria. The secondary layer is homogeneous built of very fine fibres, predominantly anisometric-like in cross-section, 25‒40 μm wide and 8‒15 μm thick. The Callovian Mughanniyya Formation of northwest Jordan is dominated by highly fossiliferous limestones intercalated with marlstone beds with very diverse brachiopod fauna, deposited in shallow, low-energy waters very near the equator. A paleobiogeographic interpretation of the brachiopod faunas in the Ethiopian Province suggests that brachiopods migrated from the north in the Early Jurassic and later became isolated for the remainder of the period.

INSIGHTS FROM A MONOSPECIFIC LINGULID BRACHIOPOD BED IN THE LATE DEVONIAN OF SOUTH AFRICA

AbstractA formerly unknown fossil-bearing locality in the lower part of the Witpoort Formation (Witteberg Group, Cape Supergroup) is described from the Eastern Cape (South Africa). Uniquely for these strata, it provides evidence for a back-barrier lagoon hosting a monospecific lingulid brachiopod fauna. This represents the youngest record of marine invertebrates within the Cape Supergroup. The occurrence extends the age range of the genus Dignomia Hall into the Famennian Stage, contrary to previous estimates of an Ordovician to mid-Devonian range. Abundant lingulid brachiopod valves are associated with plant and fish remains within a laterally extensive, up to nine-meter-thick mudstone. Shell compressions are concentrated in patches within the upper portion of the horizon and are preserved parallel to bedding as well as perpendicular and oblique to bedding (apparently in situ). Plant fossils exhibit a greater degree of transport than in other studied Witpoort Formation mudrock layers (Coombs Hill and Waterloo Farm). The monospecifity of the shelly invertebrate fauna derives from environmental stress and lingulid brachiopods' unusual ability to tolerate fluctuating environmental conditions, including salinity, oxygen levels, and temperature. Ichnofauna within the deposit include, among others, Nereites and ‘Spirophyton', suggesting opportunistic colonization of the substrate by deposit feeding invertebrates in a marine-dominated backshore setting. The Late Devonian was a time of global environmental disequilibrium, characterized by periodic flooding of continental margins and massive biotic overturn. Ongoing research into eustatic and environmental changes recorded within the Witpoort Formation uniquely provide insights into high latitude conditions during the Famennian.

Brachiopod Fauna from the Deep Mediterranean Sea: Distribution Patterns and Ecological Preferences

Compared to their fossil counterparts, living brachiopods are investigated far less often, due to their occurrence in remote environments such as dark caves or deep environments. Due to the scarcity of studies targeting in situ brachiopods’ populations, large-scale information on their distribution and ecological preferences is still lacking, especially on hardgrounds. The extensive employment of remotely operated vehicles (ROVs), however, has opened up the chance to better explore this taxon’s diversity and ecology in the mesophotic and bathyal zones. The analysis of over 600 h of video footage collected from 624 sites, from 40 m to 1825 m, located along the Ligurian and Tyrrhenian coasts of Italy and the Sicily Channel, allowed for a large-scale investigation. The four identified species, Novocrania anomala, Gryphus vitreus, Megerlia truncata and Terebratulina retusa, emerged as common macrofaunal components of the explored habitats, especially between 150 m and 250 m, with high occurrences in the northern areas, especially on offshore seamounts. All species can form dense aggregations of individuals, with M. truncata showing the densest populations on steep rocky terraces (up to 773 individuals m−2). Except for G. vitreus, the only species also recorded on soft bottoms, the others were found exclusively on hardgrounds, with N. anomala showing a peculiar ability to exploit anthropogenic substrates such as terracotta amphorae. No stable species-specific associations were noted, even if numerous species were frequently observed together. Although brachiopods do not show the conspicuous tridimensionality of large filter-feeders, their substrate occupancy and their role in pelagic–benthic processes support their importance in deep-sea Mediterranean ecosystems.

Early Toarcian (Jurassic) brachiopods from the Balearic Islands (Spain) and their paleobiogeographic context

The record of brachiopods in the Lower Toarcian of the Balearic Islands is described after a reassessment of previous works and new samplings in the Tramuntana Range of Mallorca. The recognized species have been assimilated to the assemblages described in the Iberian Range in the Tenuicostatum and Serpentinum biozones. Moreover, a detailed comparison with other Western Tethys basins and the study of the dispersion of the brachiopod faunas in relation with the Early Toarcian Oceanic Anoxic Event, allow to refine the paleobiogeographic relationship of the Balearic brachiopods. They belong to the Euro-Boreal Province of brachiopods in the Tenuicostatum Biochron and correspond to the”Spanish Fauna” that emerged after the deep paleobiogeographic disruption that took place at the base of Serpentinum Biochron. The occurrence of Prionorhynchia msougari Rousselle in the Serpentinum Zone of Mallorca indicates that, within this last assemblage, there would be a closer connection between the Balearic region and the southern margin of the Tethys (Betic and North African basins) than with the northern margin (Eastern Iberian Platform System and Eastern Pyrenees). This paleobiogeographic conclusion is consistent with the supposed position of the Balearic area in the Early Toarcian, on the southeastern margin of Iberia and near the Alboran and Kabylian margins.

Hydrothermal-bacterial structures with a brachiopod fauna on the surface of Tessel paleovolcano (South coast of Crimea)

Research subject. For the first time, the results of a study of hydrothermal-bacterial carbonate structures and a shell bank of brachiopods on the surface of the effusive sequence of the Late Triassic Tessel paleovolcano are presented. Methods. Petrographic thin sections were studied using an Olympus BX 5 microscope with an Olympus DP 12 camera. Geochemical investigations were performed according to the conventional methodology by an inductively coupled plasma mass spectrometer (ICP-MS). The isotopic composition of carbon was determined by isotope ratio mass spectrometry (IRMS) by a Deltaplus Advantage instrument. The mass spectrometer was paired with an EA Flash1112 analyzer and a TC/EA convector. When measuring, the NBS-19, NBS-18, and IAEA-C-3 standards were used. Results. The data obtained on the geology, geochemistry, and isotopic composition of the studied materials confirm the existence of a symbiosis between brachiopods and protozoa. The primary formation of organic matter and carbonate of bacterial structures occurred due to the processing of paleofluids by the community of bacteria and archaea. These organisms created carbonate, sulfide and organic matter in a suboxide environment of hydrogen sulfide and methane. The biocenosis of the shell bank of brachiopods was characterized by a poor taxonomic composition and a high biological productivity. The formation of a shell bank of brachiopods with bacterial carbonate edifices took place during the period of volcanic activity and continued during breaks in eruptions. The results of geochemistry and the carbon isotopic composition of the carbonate of bacterial buildups confirm the deep nature of the paleofluids. The Norian age of paleovolcanism was determined from finds on the surface of the terrigenous- volcanic sequence of brachiopods Worobiella ex gr. caucasica Dagys and ammonite Megaphyllites insectus (Mojsisovics). Conclusions. According to geological features, the material of the shell bank of brachiopods with bacterial carbonate structures on the surface of the Tessel paleovolcano belongs to the ancient hydrocarbon seeps-carbonate. Based on their genesis and formation material, these formations should be referred to as Triassic methanoliths. Signs of allocation of similar formations in other time intervals and regions are given. Emissions of fluids with hydrogen sulfide and methane by the Tessel paleovolcano in the Late Triassic may have been related to the causes of the “global extinction”.

Brachiopod extinctions in the Upper Cretaceous to lowermost Tertiary chalk of Northwest Europe

The white monotonous chalk from the Upper Cretaceous-lowermost Tertiary of Northwest Europe spans at least 24 million years and contains a rich, well preserved fauna of minute brachiopods. Based on taxonomical range charts and time-specific diversities this fauna is studied in terms of mean species longevity, rate of species origin and rate of extinction. The brachiopod fauna initially appears to have colonized the chalk sea in mid-Coniacian times. From there on there is a slow build-up of species diversity reflecting a gradual niche diversification of the chalk. A climax in adjustment and evolutionary stability is reached in Late Maastrichtian time. During the Coniacian-Maastrichtian interval mean rate of extinction is low (0.07 My-1) and mean rate of origination equally low (0.10 My-1). A sudden mass extinction at the Maastrichtian-Danian boundary, however, eliminated more than 70 per cent of the species. The most specialized species, in particular the secondarily free-lying species, apparently became extinct at the boundary. Only six species are known to cross the Maastrichtian-Danian boundary. These are all relatively featureless, non-specialized forms and gave, together with possible survivors in basin margin areas, rise to a rapidly formed highly diverse Early Danian fauna through adaptive radiation. The Early Danian fauna differs in taxonomic composition from the Maastrichtian fauna both on species as well as on higher levels. A dichotomous classification of extinction seems real for the brachiopods from the chalk as their mass extinction at the Maastrichtian-Danian boundary both quantitatively and qualitatively differ from their Late Cretaceous background extinction.

The Anisian (Middle Triassic) brachiopods from the southern Qilian Mountains, north‐western China

AbstractThe Anisian (Middle Triassic) witnessed the diversification of brachiopods after the Permian–Triassic extinction. The Anisian brachiopod fauna from the southern Qilian Mountains in north‐western China has the highest taxonomic diversity at species level among coeval faunas worldwide. Nevertheless, many taxa from this remote region remain poorly defined, and therefore require emendation. Here we describe 23 species (including two uncertain species) in 15 brachiopod genera based on well‐preserved carbonate and silicified specimens collected from the Anisian Dajialian and Qieermagou formations in Tianjun, southern Qilian Mountains. Two new genera (Crenulatomargus, Tianjunospina) and six new species (Costirhynchopsis xui, Crenulatomargus terebratuliformis, Schwagerispira elegans, Lepismatina? inusitata, Tianjunospina junheensis, Qilianoconcha circularis) are erected. The diagnoses of Triasorhynchia, Yangkongia, Sinucostella, Aequspiriferina, Qilianoconcha and Parantiptychia are emended. Also, the genus Eoantiptychia and the family Triasorhynchiidae are regarded as junior synonyms of Qilianoconcha and Tetrarhynchiidae, respectively. After systematic description and taxonomic emendation, 56 species (including seven uncertain species) in 26 genera are confirmed in the southern Qilian brachiopod fauna. Network analysis of 14 brachiopod faunas worldwide shows that six groups were detected during the Anisian (Qingyan, southern Qilian – western Qinling, Himalaya – northern Siberia, central Qinghai, New Zealand, and Europe/western Tethys). Compared with those from the western Tethys, the eastern Tethyan faunas are less allied to each other. Except for the assemblage from the adjacent western Qinling area, other coeval faunas have much lower affinities with the Qilian fauna.

Platymerella—a cool-water virgianid brachiopod fauna in southern Laurentia during the earliest Silurian

AbstractPlatymerella from the lower Red Mountain Formation in Georgia and Tennessee, the Bowling Green Dolomite of west-central Illinois, and the Elwood Dolomite of northeastern Illinois represents a paleosubtropical, cool-water occurrence of virgianid brachiopods in Laurentia during the early Silurian (middle–late Rhuddanian). These occurrences were located in the southern Appalachian foreland basin and the distal end of the Sebree Trough, likely subjected to frequent cool-water current and upwelling from Gondwana. Compared with broadly coeval species of Virgiana from lower paleotropical to equatorial latitudes, Platymerella has significantly smaller, dorsoventrally flattened shells, with subequal ventral and dorsal umbones and beaks that extend only slightly above the hinge line. Relative to its shell size, however, Platymerella has more prominent thickening of the shell wall, median septum, spondylium, and hinge plates than Virgiana, resembling more closely the extravagant shell thickening of Tcherskidium and Proconchidium from the Late Ordovician (late Katian) equatorial regions. The thickening of hinge plates resulted in the formation of a pseudocruralium, which separates Platymerella from Virgiana. In latest Ordovician–earliest Silurian virgianids, there was a general morphological gradient toward a smaller shell, reduction in the ventral-valve convexity, and reduction in the size and height of the ventral umbo from paleoequatorial to southern subtropical regions, with Platymerella representing the most southerly forms.

UPPER JURASSIC TO LOWERMOST CRETACEOUS MICROFOSSILS FROM THE HĂGHIMAŞ MOUNTAINS (EASTERN CARPATHIANS, ROMANIA)

The limestones of the Upper Jurassic to lowermost Cretaceous from the Hăghimaş Mountains were studied in two sections from the upper part of the Fagu Oltului valley, a tributary of the Olt River. The lower part of the succession is remarkable for the rich brachiopod fauna contained in a red limestone buildup, documented previously as a stromatactis mud-mound. The mound consists of bioclastic wackestones and packstones with numerous brachiopods, crinoids, and sponges. The mud-mound is covered with intraclastic grainstones and fine-grained limestones with pelagic bivalves. The following lithological units pass into shallow water limestone with nerineid gastropods, calcareous algae and foraminifera, in a regressive sequence. The micropaleontological association identified in the Upper Jurassic to lowermost Cretaceous limestones from Fagul Oltului includes calcareous algae, foraminifera, saccocomid crinoid fragments, annelid worm tubes, sponge fragments, rare calpionellids and microorganisms with an uncertain systematic position. The identified microfossils have a wide stratigraphic distribution. The most important stratigraphic landmarks are Trocholina conica (which does not extend younger than Kimmeridgian) and Calpionella alpina (which does not appear before the upper Tithonian). Based on the whole micropaleontological assemblage, the lower part of the succession (the skeletal mud-mound) can be ascribed to the Kimmeridgian – lower-middle Tithonian, and the upper part to the upper Tithonian – Berriasian.

New rhynchonellid and spire-bearing brachiopods from the Carboniferous of Mexico. Paleogeographical significance of the Oaxacan brachiopod fauna through the Serpukhovian–Moscovian

AbstractThis work describes a rhynchonellid and spire-bearing brachiopod fauna from the Ixtaltepec Formation of Oaxaca, Mexico.Leiorhynchoidea perrilliatae,Allorhynchus scientiana, andAnthracospirifer oaxacaensisare new species. The specific determination, along with information of previously described taxa, allowed the establishment of precise relative ages of the different fossiliferous intervals (API-1 to API-8) of the formation. The occurrence of Serpukhovian taxa in API-1 to API-3 allowed assignment of the strata to the Upper Mississippian. The presence of Bashkirian species allowed the assignment of the rocks of API-5 and API-6 to the Lower Pennsylvanian. Likewise, Middle Pennsylvanian brachiopods in API-7 and API-8 enabled correlation of the strata with the Moscovian stage. This study shows that the Ixtaltepec Formation is represented by a succession of well-delimited Serpukhovian, Bashkirian, and Moscovian rocks. Regarding paleogeography, the brachiopod fauna displays clear taxonomic variations that concur with global geological changes that occurred between the Serpukhovian to Moscovian. In the Serpukhovian intervals, we recorded numerous cosmopolitan taxa of tropical waters, coinciding with the migration pathway of the Rheic Ocean. For the Bashkirian, we observed a North American provincialism; however, because of the presence of Australian and South American species, it is proposed that the Austropanthalassic-Rheic corridor had a close connection with Oaxaca. The main provincialism was observed in the Moscovian association because most of those taxa have been reported from different localities in the United States. This study supports that the main resemblance between Oaxacan and North American faunas continued until the Pennsylvanian and not the Mississippian, as was previously proposed.UUID:http://zoobank.org/181e49cf-a08a-4e99-8200-65f4a90dafcd

Reef-dwelling brachiopods record paleoecological and paleoenvironmental changes within the Changhsingian (late Permian) platform-margin sponge reef in eastern Sichuan Basin, China.

The eastern Sichuan Basin area (China) is the representative locality for studies of the Late Permian Changhsingian platform to basin transition. However, details of the paleoecology and paleoenvironment of rich brachiopod fauna in this area are still unclear, especially regarding the reef-dwelling brachiopods. The reef-dwelling brachiopod specimens from the Panlongdong platform-margin reefal environment are first described herein. A detailed comparison is presented with the paleoecological features and sedimentological characteristics of the reef-dwelling brachiopods and brachiopods of the reported Zhongliang Hill and Huayingshan intraplatform nonreefal environments in the transitional zone. The reef-dwelling brachiopods are dominated by the spiriferids, such as Martinia and Permophricodothyris, which are mainly found in hypercalcified sponge-calcareous algae binding framestone from the second reef-building process of the Panlongdong reef. The brachiopods in the first and third reef-building processes of the Panlongdong reef often show clear indications of transportation. The comparison of paleoecological and sedimentological evidence indicates that the reef-dwelling brachiopod specimens, which have strong pedicle-attached convex shells and supporting body spines, are commonly preserved in live positions and form a hard-bottom fauna, showing low evenness, and high dominance in both taxonomical and lifestyle diversity. The association among reef-dwelling brachiopod individuals also represents potential biological interactions to prevent the shells from being swept away by constant currents and waves, forming extremely dense concentrations on the sea floor as reef ecosystem engineers. This case study of reef-dwelling brachiopods preserved within the platform-margin reefal environment was critical for filling various gaps in our knowledge of the complexity of the Changhsingian reef-related ecosystem.

Palaeotectonic reconstructions of the Central Asian folded belt in the Silurian Tuvaella and Retziella brachiopod fauna locations

Palaeotectonic reconstructions of the Central Asian folded belt in the Silurian <i>Tuvaella</i> and <i>Retziella</i> brachiopod fauna locations

Quantitative palaeobiogeography of the Kungurian–Roadian brachiopod faunas in the Tethys: Implications of allometric drifting of Cimmerian blocks and opening of the Meso-Tethys Ocean

Benthic faunas and their palaeobiogeographic affinities related to climate gradient can provide insightful information to unravel the tectonic histories of their hosted blocks if they moved across different latitude zones. In this study, three different quantitative analyses (network, cluster and non-metric multi-dimensional scaling analyses) are employed to carry out a palaeobiogeographic study of the Kungurian–Roadian brachiopod faunas of the Cimmerian blocks. A spin-glass algorithm that enables network community detection is here used for the first time and its six groups-partition is considered as the optimal solution. Two new palaeobiogeographic subprovinces, the Southern and Northern Cimmerian subprovinces in the Southern Transitional Zone, are first recognised besides the previously perceived Cathaysian, Transhimalayan, Westralian and Austrazean provinces. Based on distinct palaeobiogeographic discrepancies, it is suggested that the Lhasa, Tengchong and Irrawaddy blocks, constituting the main parts of the Southern Cimmerian Subprovince, were probably situated near the peri-Gondwanan region; whereas the South Qiangtang, Baoshan and Sibuma blocks of the Northern Cimmerian Subprovince probably were located in the temperate region of the southern hemisphere during the Cisuralian to Guadalupian transition. Such discrepancies in palaeobiogeographic affinitites between two continental slices imply that the Meso-Tethys Ocean had existed before the late Cisuralian and its present oceanic remnants are represented by the Bangong-Nujiang Suture Zone in central Tibet, the Gaoligongshan shear zone in western Yunnan and the Medial-Myanmar Suture Zone in southern Myanmar and Peninsula Thailand. Moreover, the Neo-Tethys Ocean had likely co-existed with the Meso-Tethys Ocean during that time. Given that all these blocks were attached to the northern peri-Gondwanan margin during the early Cisuralian, the Kungurian-Roadian faunal discrepancies among different continental slices with a distinct latitude gradient can be interpreted by the allometric northward drifting of the Cimmerian blocks, which led to the formation of the Meso-Tethys and Neo-Tethys oceans.