The earliest known strophomenoids (Brachiopoda) from early Middle Ordovician rocks Of South China

The upper Daguanshan Formation (middle Expansograptus hirundo graptolite biozone, Dapingian, early Middle Ordovician) of the Shuanghe area, Changning County, southern Sichuan Province, contains three new genera and species of strophomenoids: Ochyromena plana, Shuangheella elongata, and Primotimena globula, which are attributed to the Strophomenidae, Rafinesquinidae and Glyptomenidae respectively. These are the earliest known strophomenoids from the South China palaeoplate, and also the oldest rafinesquinid and glyptomenid brachiopods worldwide. Global review of the superfamily Strophomenoidea of Middle Ordovician age suggests that the first diversity peak at the species level occurred in late Darriwilian (Llanvirn) time, mainly as a result of the rapid diversification of the family Strophomenidae. The first appearance datum (FAD) of strophomenoids and their possible westward dispersal were from North China (latest Floian) and/or South China (early Dapingian), through the Chu‐Ili terrane of Kazakhstan, Iran, and Baltica (early Darriwilian), to Avalonia and Laurentia (late Darriwilian). This points to the existence of early diversification hotspots of the strophomenoid superfamily in the North and South China palaeoplates during the early Middle Ordovician in generally shallow water (corresponding to BA2) environments. The high degree of similarity in the external morphology and ventral interior of the three new genera indicates that the early diversification of strophomenoids began with differentiation of the cardinalia, especially in the configuration of the bilobed cardinal process, a key evolutionary novelty for the strophomenoids.     

Family Lycophoriidae (Brachiopoda) from the Ordovician of Baltoscandia

The family Lycophoriidae from the Middle Ordovician of Baltoscandia with one monotypic genus and five species is revised. New inner structures were revealed and diagnoses of the family, genera, and species were specified in the study of cross sections and microstructure of the shell. The third prismatic layer, complex dental plates, and socket ridges with short pointed lateral outgrowths were recorded. The family Lycophoriidae cannot be assigned with confidence to any known brachiopod order.     

Foliomena Fauna (Brachiopoda) from the Upper Ordovician of Sardinia

The late Ordovician brachiopod assemblage from Sardinia is one of the youngest members of the deep-water Foliomena fauna and is characterized by the following core taxa: Christiania , Cyclospira , Dedzetina and Foliomena . The fauna also contains Epitomyonia , Leangella , Glyptorthis and Skenidioides , which are more typical of shallower-water environments during the late Ordovician but occupied deeper-water niches during the Silurian following the termination of the Foliomena fauna. The suprafamilial placement of the family Chrustenoporidae is discussed and the new species Dedzetina serpaglii and Leangella ( Leangella ) fecunda are established. In common with many mid-Ashgill Foliomena faunas the Sardinian assemblage shows significant differences from other faunal developments of this type, reflecting its geographical position and shallower water conditions than those of the classic early Ashgill Foliomena faunas. The brachiopods occur with abundant trilobites belonging to a variant of the cyclopygid fauna. The faunas developed on part of a complex of microcontinents derived from peri-Gondwana during the Ordovician.     

New Upper Cambrian Lingulata (Brachiopoda) from the Agyrek mountains (northeastern central Kazakhstan)

Two new genera, Repkinella and Aristotreta, and five new species from the class Lingulata (Brachiopoda) are described from the Upper Cambrian olistolith limestone enclosed in the Upper Ordovician olistostrome from the Agyrek mountains (northeastern Kazakhstan). The family Curticiidae Walcott et Schuchert is referred to the order Lingulida, not order Acrotretida, where it was previously placed.     

The latest Ordovician Hirnantia Fauna (Brachiopoda) in time and space

The diachronous temporal and spatial distribution of the Hirnantia brachiopod fauna and the complicated pattern of terminal Ordovician events are documented through biostratigraphical analysis of the Ordovician-Silurian boundary strata in S China, Sibumasu, Xizang and elsewhere. The duration of these events (longer than the half Myr derived from isotopic excursions) indicates that they were not abrupt and instantaneous. The presence of some core taxa of the Hirnantia fauna in the upper P. pacificus Biozone (known from their earliest occurrence in China) signals the start of increased water ventilation due to the invasion of cool water across the Yangtze Basin. Low- and higher-diversity Hirnantia faunas related to onshore, shallow-water and to offshore, deeper-water environments, respectively, developed first in the basal and upper N. extraordinarius-N. ojsuensis Biozone. Disappearance of most of the fauna in the early N. persculptus Biozone suggests that the glacial maximum started to decline. The presence of the Hirnantia fauna in the upper N. persculptus to the lower P. acuminatus biozones indicates the continuation of cool water environments in some places. The diachronous disappearance of deteriorating environments (earlier in later Hirnantian and finally in the early Rhuddanian) is associated with geographical heterogeneity. Occurrences of atrypids, pentamerids and spiriferids along with key elements of the Hirnantia fauna in N Guizhou provide a link between the Late Ordovician radiation and Early Silurian recovery of these major brachiopod groups.     

Middle Ordovician (Llanvirn) ungulate brachiopods and conodonts from the Malyi Karatau Range,Kazakhstan

A new middle Ordovician fauna including conodonts and brachiopods is described from the early Llanvirn Zhyrykaus Formation, Malyi Karatau Range, southern Kazakhstan. The fauna includes the lingulate brachiopodsHyperobolus fragilis n. sp. andTalasotreta apollonovi n. gen. n. sp., as well as the conodontsCordylodus? cf.horridus, Drepanoistodus? sp.,Erraticodon sp.,Parapaltodus simplicissimus, Prioniodus (Baltoniodus) sp.,Protopanderodus cf.varicostatus, andWalliserodus sp. s. f. It represents the first record of Llanvirn conodonts and Ungulate brachiopods from southern Kazakhstan.     

Early–Mid Ordovician Yangtzeella (Syntrophiidina, Brachiopoda) and its evolutionary significance

Abstract:  Re-examination of newly collected topotype material confirms that the type species of Yangtzeella , Y .  poloi , a widespread Early and Mid Ordovician syntrophiidine brachiopod in South China, has a finely costellate shell rather than being smooth as previously thought. Thus, the subgenus Yangtzeella ( Vadimella ) Nikitina et   al ., established on the basis of fine costellae, is invalidated. Among 15 species of Yangtzeella , five species are recognized as valid based on multivariate analyses: Y .  poloi , Y .  unsulcata , Y .  songziensis , Y .  kueiyangensis and Y .  igori , among which the type species was the oldest known. Six are synonymized: Y .  septata , Y .  reticulata , Y .  lensiformis , Y .  depressa , Y .  yichangensis and Y .  minuta . Four are rejected from Yangtzeella : Y .  extensa , Y .  similior , Y .  yohi and Y .  poloi var. minor . Regional biostratigraphy indicates that Yangtzeella first appeared in a relatively deep-water setting on the Lower Yangtze Platform (South China palaeoplate) during late Tremadoc time ( Scolopodus warendensis conodont biozone) and then expanded to the deeper Jiangnan Slope as well as to the shallower Upper Yangtze Platform. The genus experienced two episodes of heightened abundance and diversity on the Upper Yangtze Platform during late Dapingian and mid Darriwilian times, respectively. Outside South China, Yangtzeella occurs sporadically in a few microplates or terranes, such as Tarim, Chu-Ili (southern Kazakhstan) and Taurides (southern Turkey) during the Dapingian and Darriwilian. Worldwide, Yangtzeella became extinct by the end of the Darriwilian.     

Latest Helcionelloid Molluscs from the Lower Ordovician of Kazakhstan

The helcionelloid mollusc Chuiliella elenae gen. et sp. nov. is described from the Lower Ordovician of Kazakhstan. It represents the geologically youngest record of a group of mainly bilaterally symmetrical ancient molluscs which originated in the earliest Cambrian, flourished during the early–mid Cambrian and was thought to have become extinct during the late Cambrian. Chuiliella is a typical helcionelloid in terms of shell shape, although the comarginal ornamentation characteristic of many helcionelloids is lacking. Interpretation of the raised margin of the aperture adjacent to the earlier coiled whorl as exhalant channels favours reconstruction of helcionelloids as endogastrically coiled, i.e., with the apex posterior.     

Palaeobiogeographic distribution patterns and processes of Neochonetes and Fusichonetes (Brachiopoda) in the late Palaeozoic and earliest Mesozoic

The global palaeobiogeographic distributions of two resembling genera, Neochonetes and Fusichonetes (Brachiopoda), from the Carboniferous to Griesbachian are analysed. This analysis provides insight into the biotic response of two related genera to changing palaeoclimate, regional tectonics, and environmental crises. Neochonetes originated in the equatorial area in the Mississippian, and it mostly retained this position during the peak of the glaciation in the Carboniferous–Permian ice age (namely in the Pennsylvanian). Neochonetes then dispersed globally during the Cisuralian when the climate became warmer and the ice sheet started to retreat. In the Guadalupian and Lopingian, following the closure of the Ural seaway at the end of the Cisuralian and the regression at the end-Guadalupian, Neochonetes almost disappeared in the western part of Gondwana. Subsequently during the Lopingian the genus retracted to the middle- and low-latitude Palaeo-Tethys and Tethys. In comparison, Fusichonetes originated in the equatorial area in the late Guadalupian and was still present in that area in the Lopingian. Both genera occurred only in South China in the Griesbachian. It is inferred that this could be related, not only to the deteriorated palaeoenvironmental conditions (e.g., anoxia, global warming) leading up to the extinction of most of the Neochonetes and Fusichonetes species in other areas, but also to the better physiological adaptation of the smaller shells of Neochonetes and Fusichonetes species in South China.     

Morphometric analysis of Tremadocian (earliest Ordovician) kirkocystid mitrates (Echinodermata, Stylophora) from the Taebaeksan Basin, Korea

Abundant isolated remains of stylophoran echinoderms (cornutes and mitrates) are reported for the first time in the late Tremadocian (Asaphellus Zone) Tumugol Formation of Korea. Mitrate remains include numerous adorals of Kirkocystidae. Several new important anatomical features have been observed on these adorals, as an internal calcitic layer that is associated to s₂ and possibly also to the palmar complex. This observation suggests that the palmar complex would be present not only in mitrocystitid mitrates, but also in peltocystitids. For the first time, several morphometric analyses have been undertaken based on isolated kirkocystid adorals, so as to explore the morphological diversity displayed by Korean adorals, but also in order to compare their morphology with that of other Gondwanan kirkocystids. Morphometric analyses indicate the occurrence of two contrasted morphologies within Korean adorals (morphotypes A and B), and of three distinct morphologies within European and North African forms (“Anatifopsis”, “Balanocystites”, and “escandei” morphotypes). Comparison of Korean adorals with those from Europe and North Africa shows that: (1) morphotypes B and “Anatifopsis” are equivalent; consequently, the two Korean specimens referred to morphotype B are assigned to the genus Anatifopsis; (2) morphology of most Korean adorals, which belong to morphotype A, is clearly distinct from that of all other described kirkocystids from Europe and North Africa. The small size, juvenile morphology, and great morphological variability observed in the morphotype A of the Korean adorals are suggestive of possible heterochronic processes (peramorphosis).     

Conodonts from the upper Ordovician siliceous rocks of Central Kazakhstan

Several conodont localities of the upper Sandbian Stage are known in siliceous deposits of Central Kazakhstan. All of them produced similar assemblages overwhelmingly dominated by Periodon grandis with insignificant admixture of Scabbardella altipes, Hamarodus europaeus, Pygodus anserinus, Protopanderodus sp., and Drepanodus sp. The main feature of this fauna is in the co-occurrence of H. europaeus and P. grandis, forms characteristic for deep-water facies at shelf or microcontinents margins of temperate and warm-water paleobiogeographic provinces. The Ordovician paleo-oceanic basin of Kazakhstan and southern Urals were parts of the uniform biogeographic area as indicated by similarity of Ordovician conodont assemblages in siliceous deposits of these regions.     

Tremadoc (earliest Ordovician) brachiopods from Purmamarca and the Sierra de Mojotoro, Cordillera Oriental of northwestern Argentina

The Late Tremadoc storm-dominated shoreface to inner platform deposits exposed west of the Purmamarca village (Coquena Formation) contain a considerably more diverse brachiopod fauna than previously reported. Coquinite horizons from the lower heterolitic succession have yielded monospecific associations of Nanorthis purmamarcaensis nov. sp. (formerly assigned to N. christianiae KJERULF), which is also reported from the Late Tremadoc rocks of the Cerro San Bernardo area. The fine-grained Upper Member of the Coquena Formation contains a more diverse fauna composed by Nanorthis brachymyaria nov. sp., Astraborthis quebradensis nov. sp. and the new plectorthid genus Lipanorthis (type species L. andinus nov. sp.). A different species of Lipanorthis (L. santalaurae nov. sp.) from the Mid Tremadoc Floresta Formation of the Sierra de Mojotoro is also described.     

Silurian Leptaeninae (Brachiopoda) from Gotland, Sweden

Strophomenid brachiopods belonging to the generaLeptaena andLepidoleptaena are described from the uppermost Llandovery — Ludlow succession of Gotland, Sweden. In Gotland,Lepidoleptaena comprises the single speciesL. poulseni, andLeptaena includes four species:L. rhomboidalis, L. sperion, L. depressa andL. parvirugata n. sp.L. depressa shows a considerable amount of morphological variation, which is recognised in the two new subspeciesLeptaena depressa visbyensis n. ssp. from the Llandoverian — Wenlockian Visby Formation, andL. depressa lata n. ssp. from the mid-Wenlockian Slite Group. The distribution of the different species is largely substrate-dependent, withLeptaena rhomboidalis andLepidoleptaena poulseni adapted to high-energy environments with firm substrates, whereas the remaining species preferred fine-grained substrates in low-energy environments.      

New Upper Devonian Rhynchonellids (Brachiopoda) from Transcaucasia

Anew genus, Zezinia gen. nov., and two new species, Zezinia multicostata sp. nov. and Zaigunrostrum nakhichevanense sp. nov., are described from the Upper Devonian of Transcaucasia. The first genus is one of the last Frasnian representatives of the family Uncinulidae. The Famennian Z. nakhichevanense sp. nov. belongs to punctate rhynchonellids of the family Trigonirhynchiidae.     

The genusPlatythyris (Brachiopoda) and its relationship to the Pygopidae

Platythyris is included in the Pygopidae because of the resemblance of its internal structures to that family, despite the great difference in external form. The genus occurs in strata of Barremian to Senonian age in Europe north and west of the Alpine line and probably originated in the Caucasian-Crimean region. Three new species are described:P. vendeensis (Cenomanian),P. cristobali (Turonian) andP. viaudi (Senonian).Terebratula squamosa Mantell (Cenomanian) is assigned toPlatythyris and redescribed.Terebratula disparilis D’Orbigny (Cenomanian) is described as a subspeciesP. squamosa disparilis.     

New Devonian punctate rhynchonellids (Brachiopoda) from Transcaucasia

New genus and species of punctate rhynchonellids Sharovaella mirabilis are described from the Famennian (Upper Devonian) of Transcaucasia.     

New Late Devonian strophomenids (Brachiopoda) from Mongolia

Two new strophomenid species, Leptagonia barunkhuraica sp. nov. (Famennian) and Floweria mongolica sp. nov. (Frasnian), from the Upper Devonian of the Barunkhurai Depression of southern Mongolia are described.     

New Atrypids (Brachiopoda) from the Lower Devonian of Northeast Russia

New atrypids are described from the Lower Devonian of Northeast Russia: Musalitinispira, gen. nov. with type species M. dogdensis, sp. nov. (subfamily Atrypinae), Spinatrypina (Spinatrypina) krivensis, sp. nov., and Datnella, gen. nov. with type species D. datnensis (Baranov, 1995) (subfamily Spinatrypinae).     

Pentamerids (Brachiopoda) from the Lower and Middle Devonian of Northeastern Asia

Pentamerids (Brachiopoda) are described from the Lower and Middle Devonian of northeastern Asia: Antirhynchonella cherkesovae sp. nov. belonging to the family Clorindidae and Devonogypa indigirica (Sidjachenko), Vadimia gen. nov. with the type species V. gonensis sp. nov. and V. naanchanensis sp. nov., and Vladimiria gen. nov. with the type species Vl. yanensis sp. nov. all belonging to the subfamily Devonogypinae.