Brachiopods Research Articles

THE ATHYRIDOIDS OF THE TRANSITIONAL BEDS BETWEEN BELLEROPHON AND WERFEN FORMATIONS (UPPERMOST PERMIAN, SOUTHERN ALPS, ITALY)

The transitional beds between Bellerophon and Werfen Formations, few centimetres thick and latest Permian in age, contain a brachiopod fauna with a relatively rich athyridoid assemblage, among which Janiceps is the most common and characteristic genus. The internal morphology of the type species ( J. peracuta ) is here described for the first time, and a taxonomical revision of the South Alpine species is proposed. The new subfamily Janiceps inae is proposed, which contains Janiceps and the new genus Comelicothyris . Among the latter genus, Comelicothyris laterosulcata n. sp. is suggested. Lectotypes are selected and illustrated for Spirigera janiceps Stache, S. confinalis Stache, S. bipartita Stache, S. ? archimedis Stache, Spirifer ? sextensis Stache, Athyris irregularis Merla, A. semilunaris Merla, and A janiceps var globulus Merla. The athyridoids of the transitional beds are characterized by a broad morphological variability which induced past authors to create many species and ivarietiesi generally on the bais of a single or few individuals. As concerns Janiceps , only four species-versus the 14 species and 7 ivarietiesi cited in the literature of the Souther Alps-are here considered valid ( J. peracuta (Stache), J. cadorica (Stache), J. papilio (Stache), and J. bipartita (Stache)). Besides other four species are identified here; these are Comelicothyris recticardinis (Merla), Septospirigerella ? sp., Spirigerellinae gen. et sp. indet., and Comelicania merlai Posenato.

A NEW SYRINGOTHYRIDID GENUS (SPIRIFERINIDA, BRACHIOPODA) FROM THE EARLY PERMIAN OF INTERIOR OMAN

Representatives of the Syringothyrididae (Spiriferinida) are a significant component of the Early Permian brachiopod faunas, even if usually subordinate in number of specimens, except for the Interior of Oman, where they dominate the faunal assemblage. A new genus Pachycyrtella - with type-species P. omanensis n. sp. - is here established in order to include gondawanan species - previously assigned to the genus Cyrtella - characterized by high and apsacline to orthocline ventral interarea, thick umbo and deep dorsal median furrow.

Monophyly of brachiopods and phoronids: reconciliation of molecular evidence with Linnaean classification (the subphylum Phoroniformea nov.)

Molecular phylogenetic analyses of aligned 18S rDNA gene sequences from articulate and inarticulate brachiopods representing all major extant lineages, an enhanced set of phoronids and several unrelated protostome taxa, confirm previous indications that in such data, brachiopod and phoronids form a well-supported clade that (on previous evidence) is unambiguously affiliated with protostomes rather than deuterostomes. Within the brachiopod-phoronid clade, an association between phoronids and inarticulate brachiopods is moderately well supported, whilst a close relationship between phoronids and craniid inarticulates is weakly indicated. Brachiopod-phoronid monophyly is reconciled with the most recent Linnaean classification of brachiopods by abolition of the phylum Phoronida and rediagnosis of the phylum Brachiopoda to include tubiculous, shell-less forms. Recognition that brachiopods and phoronids are close genealogical allies of protostome phyla such as molluscs and annelids, but are much more distantly related to deuterostome phyla such as echinoderms and chordates, implies either (or both) that the morphology and ontogeny of blastopore, mesoderm and coelom formation have been widely misreported or misinterpreted, or that these characters have been subject to extensive homoplasy. This inference, if true, undermines virtually all morphology-based reconstructions of phylogeny made during the past century or more.

Part H, Brachiopoda (Revised), vol. 2 & 3, ch. 4, p. 424–565

Part H, Brachiopoda (Revised), vol. 2 & 3, ch. 4, p. 424–565

Ornamentación desarrollada por algunos braquiópodos del orden Athyridida

Different types of external athyridid ornamentation are described and the presence of hollow spines (commonly considered as exclusive of other orders of articulated brachiopods) is clearly showed in the parazygids (group which appear as ancestral of all other rhynchospirinoids).

Distribución paleogeográfica de Aseptella (Productida): Conexión entre los braquiópodos carboníferos de España y Argentina

Aseptella is a genus of productids described from Spain (Cantabrian Mts: the Bashkirian type species A. asturica and the Visean-Arnsbergian A. beetsi) and from Argentina (A. patriciae from the Lower Permian –although a Late Carboniferous age cannot be excluded– and A. aff. patriciae, from Upper Carboniferous strata slightly higher than the Lanipustula Zone). A. beetsi, ancestor of the other species, has a weakly developed median septum in the dorsal valve interior, which is absent in the adults of A. asturica and in the Argentinian forms. The brachiopods of the Lanipustula Zone show not only relations with those from Australia and the United States but also with those from the Cantabrian Mts, especially with those forms typical of a quiet water environment, which was rather deep and therefore more obscure and colder than normal for the latitude. The rather small forms could have drifted across the Tethys –possibly as larvae entangled in seaweed– at the begining of the Late Carboniferous and have adapted to the environment that reigned in Argentina at that time.

CARNIAN REEF BIOTA FROM A MEGABRECCIA OF THE HAWASINA COMPLEX (AL AQIL, OMAN)

Carnian reef biota and brachiopods of the Misfah Formation (Hawasina complex) from a locality near the town of Al Aqil in Oman are described. A new brachiopod species, Oxycolpella arabica n. sp. is described. The composition of the Carnian reef biota in Oman is similar to those known from the Alpine-Mediterranean region. However, differences exist in the microfauna of reef dwellers, e.g. foraminifers. New stratigraphic data based on reef organisms and conodonts are presented.

Bully for Brachiopods

Bully for Brachiopods

Neue Daten bezüglich der Systematik einiger spiriferider Brachiopoden aus dem Famenne von Afghanistan und Iran

Following revision of Famennian spiriferid brachiopods from Afghanistan and Iran, some species inBrice (1971),Golshani, Janvier, Brice & de Lapparent (1973),Djafarian & Brice (1973),Brice inBrice, Lafuste, de Lapparent, Pillet & Yassini (1974),Brice, de Lapparent & Mistiaen (1975),Brice & Farsan (1977),Brice, Jenny, Stampfli & Bigey (1978) andBrice inMistiaen (1985) are reassigned taxonomically and additional data are presented for others.Cyrtospirifer crassiplicatusBrice (1971) and its two subspecies are reassigned toRigauxiaBrice 1988. Internal structures are illustrated and information on distribution are presented forEobrachythyrisBrice 1971, emended 1997. The following Afghan and Iranian forms referred to previously described species are now considered to be new:Prospira lapparenti sp. nov. [=Eobrachythyris strunianus alatus (Gosselet 1879) ofBrice (1971)];Unispirifer persianum sp. nov. [=Unispirifer e. g.mediocris (Tolmatchof 1924) ofBrice (1971)];Cyrtospirifer orthogoniformis sp. nov. [=Cyrtospirifer quadratusNalivkinsensuBrice (1971)]. Internal characters ofToryniferella echinulataBrice 1971, are illustrated. Moreover,Sulcatospirifer iranicus sp. nov. [=Cyrtospirifer syringothyriformisPaeckelmann nov. subsp. ofBrice inGolshani, Janvier, Brice & de Lapparent 1973] is described from the Lower-Middle Famennian of Iran.

PROBLEMS IN STUDIES ON CARBON AND OXYGEN STABLE ISOTOPES IN CARBONATES

Carbon and Oxygen stable isotopes in carbonates have long been the important geochemical tracers. Studies on the isotopic compositions can provide insights into the paleoclimatic processes, the paleoceanic environmental processes and the geological processes as well. Researches of more than four decades in the field, especially from the early 1980s on, during which the analysis of the isotopes in fossil brachiopods and early diagenetic cements has contributed much to the knowledge, achieved appreciable progress. However, problems still remained with how to explain the data that already existed on the isotopic compositions of carbonates, on which there is a dichotomy between those who advocate that the data represent the original characteristics of the isotopes and those who argue that the data have been altered diagenetically; with how to select the samples of carbonate for analysis of the isotopic ratios, which has a set of criteria, namely, the microstructure, the Cathodoluminescence and trace elements, for tests of the sample preservations; with whether the fossil brachiopods′ shells have vital effects on the isotopic compositions, on which there is a tendency toward the existence in recent years; with to what extent the living environment variations of the fossil affect their carbon and oxygen isotopic ratios and with the utilization of early diagenetic cement as analyzing samples. Along with the problem raising, this paper reviewed the methods on, and new developing trends toward, the problem solvings, as well as the up to date advances of studies on each problem.

LATE CARBONIFEROUS BRACHIOPODS FROM KARAKORUM, PAKISTAN

Carboniferous rocks from North Karakorum display sharp lateral variations in lithology and thickness suggesting accumulation in half-grabens during continental rifting between the Karakorum block and northern Gondwana. Different Carboniferous successions, belonging to distinct tectonic units, have been detected. Thin, poorly fossiliferous successions of arenites and crinoidal limestones contrast with very thick terrigenous-carbonate successions comprising two distinct fossiliferous horizons. The lower fossiliferous horizon yielded brachiopods ( Pustula sp., Rhipidomella sp., Choristites sp., Martiniopsis sp., Afghanospirifer sp., Gypospirifer sp., Composita sp.) of Bashkirian age. The upper fossiliferous horizon, lying about 90 m above the former, contains corals, crinoids and brachiopods ( Densepustula cf. losarensis , Dowhatania sulcata n. sp., Brachythyris sp., Rhipidomella sp., Septacamera dowhatensis , A lispirifer middlemissi ) of Moscovian to Kasimovian age. The Carboniferous brachiopods of North Karakorum are similar to those collected in the Late Carboniferous of Central Afghanistan, Himalaya (Manang, Spiti, Tibet), and Lhasa Block (Xainza area).

First Permian Ostracode Fauna from the Arabian Plate (Khuff Formation, Sultanate of Oman)

First Permian Ostracode Fauna from the Arabian Plate (Khuff Formation, Sultanate of Oman)

EVIDENCE OF A GUADALUPIAN AGE FOR THE KHUFF FORMATION OF SOUTHEASTERN OMAN: PRELIMINARY REPORT

The Guadalupian succession of the Huqf area (Sultanate of Oman) represents a mega-sequence comprising the fluvial terrigenous Gharif Formation and the overlying marine Khuff Formation. The Khuff Fm. is subdivided into four members and is composed of marls and bioclastic limestones. The Khuff Fm. yields a rich fauna of brachiopods, conodonts, foraminifers, bivalves, gastropods, ostracods and cephalopods. The brachiopod fauna of the Khuff Fm. includes strophomenids, productids, orthids and terebratulids. The associated conodont fauna includes Hindeodus excavatus Behnken, Merrilina sp., M. praedivergens Kozur & Mostler, and Sweetina n. sp. (systematic descriptions of conodonts are given in the Paleontological Appendix). Foraminifers are represented by species of Miliolina and Rotaliina. The Khuff Fm. is given a Wordian age, based on brachiopods and conodonts. The depositional environment of the Khuff Fm. of southeastern Oman corresponds to the outer shelf of a large carbonate platform covering most of the Arabian Platform. The Khuff Fm. is interpreted as a major transgressive-regressive cycle related to differential subsidence.

THE GEN. COMELICANIA FRECH, 1901 (BRACHIOPODA) FROM THE SOUTHERN ALPS: MORPHOLOGY AND CLASSIFICATION

Analysis of the internal characters, especially the cardinalia and brachidium, of the brachiopod Comelicania Frech from the Southern Alps, confirmed the attribution of this genus to the Superfam. Athyridoidea Davidson and provided a more complete taxonomic description of the Fam. Comelicaniidae Merla. This family includes two genera which differ in the morphology of their cardinalia, i.e. Gruntallina Waterhouse & Gupta, type-species Gruntallina triangularis (Grunt) from the lower Dorashamian of Transcaucasia and Comelicania , type-species Comelicania megalotis (Stache) from the uppermost Bellerophon Fm. of the Southern Alps. The study of a collection composed of more than a hundred specimens highlighted a broad variability of the morphological characters and a pattern of ontogenetic development which demonstrates that classification at the species level is possible only when using mature specimens. Taxonomic revision at the specific level reduced the eleven species of Comelicania from the Southern Alps, described by previous authors, to: C. megalotis (Stache) and C. haueri (Stache). In addition a new species, C. merlai , which characterises the upper Comelicania beds, is proposed.

JURASSIC PALAEOGEOGRAPHY OF THE TRANSDANUBIAN CENTRAL RANGE (HUNGARY)

The Transdanubian Central Range (TCR) is a flattened range of hills in northern Transdanubia (Hungary), formed mainly by Mesozoic carbonate rocks showing strong facies similarities with the Southern Alps and the Austroalpine domain. The Jurassic system is divided into several formations of predominantly pelagic limestones. Ammonoids are frequent and were collected bed-by-bed in numerous sections, providing an excellent biostratigraphic resolution. The thickness of the Jurassic system is usually small but changes along the strike of the TCR. It reaches a maximum thickness of 500 m in the western part; is very variable (10-400 m) in the central segment (Bakony Mts.) and rather low (less than 100 m) in the east (Gerecse). In the Bakony segment, the thickness variation reflects the strongly dissected topography of the Jurassic sea-floor. Synsedimentary tectonics is dominated by normal faults; tilted blocks and listric faults may be inferred only in the east. Five main steps were identified in the palaeogeographic evolution: 1) Late Hettangian: carbonate oolitic shoals prevail, except for a few sites where non-deposition or neritic sediments occur. 2) Sinemurian and Pliensbachian: tectonic disintegration resulted in an intricate pattern of submarine horsts and intervening basins, with condensed sedimentation or non-deposition on the horsts and thicker, continuous sedimentary sequences in the basins. The submarine topographic highs are surrounded by aprons of redeposited material (scarp breccias, brachiopod coquinas, crinoidal calcarenites, spiculitic cherty limestones), while pure or argillaceous limestones (Rosso Ammonitico) prevail in the distal areas. 3) Early Toarcian: the Tethys-wide anoxic event is superimposed on the previous submarine bottom topography; the resulting black shales and sedimentary Mn-ores are concentrated on the western sides of some horsts. 4) Dogger to Early Malm: radiolarites with heterochronous lower and upper boundaries (Aalenian to Kimmeridgian) prevail, except for the top of some submarine topographic highs. The absence of uppermost Bathonian to Lower Oxfordian carbonates suggests that the whole TCR sunk below the CCD in those times. 5) Latest Jurassic: the uniform deposition of Rosso Ammonitico and Biancone in the Late Kimmeridgian and Tithonian is interrupted only in the Early Tithonian by local intercalations of scarp breccias and coarse biodetrital limestones. This is interpreted as the last manifestation of synsedimentary tectonic movements along the faults bordering the submarine horsts. Based on palaeogeographic similarities and analogies in Jurassic times, the TCR is visualized as the northern foreground of the Trento platform/plateau (lying north of the later Insubric lineament), where the block-tectonic disintegration and differential subsidence started earlier and resulted in a bottom morphology more dissected than in the South Alpine part of this west Tethyan passive margin.

Mr. Greene and His Brachiopods

Mr. Greene and His Brachiopods

Some morphological problems of brachiopod taxonomy

Some morphological problems of brachiopod taxonomy

Three new Devonian chonetoidean Brachiopods

Three new Devonian chonetoidean Brachiopods

PERMIAN STRATIGRAPHY IN THE NORTHERN KARAKORUM, PAKISTAN

The stratigraphical data collected during four geological expeditions to the Northern Karakorum (1996,1991,1992a,1992b) are discussed. The sedimentary succession has been classified by 9 formations, here formalised, and subdivided into members and lithozones. The biochronology has been established on fusulinids, brachiopods, and conodonts. Several plates illustrate the most significant fossil species as well as the litho- and microfacies. The sedimentary succession may be roughly subdivided into three parts. The lower part consists of terrigenous rocks, mostly pelitic and less frequently arenaceous(quartzarenites with thick arkose intervals during the latest Asselian-early Sakmarian). They are evidence of a continental to coxtal environment, with short term marine ingressions. The second part begins with the Sakmarian, when the marine environment spread over most of the studied area. Bioclastic sand bars with brachiopods and crinoids at the base are followed by huge fusulinid packages. In Hunza oolitic bars and dolostone peritidal cycles also follow. The carbonate ramp is often polluted by terrigenous sediments, especially westwards. Temporary arenaceous spillovers (quartzarenites), often linked to minor sedimentation gaps, occur both westwards in the Baroghil area, and eastwards in the Hunza-Shimshal area. In the centre, in the Upper Karambar valley, a large gap most probably occurs, with reappearance of the sedimentation only with the dolostones of the Upper Permian. These erosional episodes with arenaceous spillovers are interpreted as being linked to rifting events of the Neotethys opening, active southwards. The third part of rhe succession concerns the Late Permian. Towards the end at the Murgabian or at the beginning of the Midian, the Northern Karakorum is subdivided into two major areas. To the west, after a transgressive episode with ironstone deposition, a wide peritidal carbonate platform spread over from Baroghil to Chillinji in Karambar and the Pasu area in Hunza. This palaeogeographic pattern extends up to the Triassic. However, biostratigraphic control is poor. Instead to the north-east, a progressive sinking of the slope is observed, with spreading of deeper environments and cherty limestone deposition. The down-warping is activated by block-faulting resulting in huge megabreccia bodies interbedded with the cherty limestones. During the Dzhulfian, significant clay inputs dilute the carbonate mud accumulation and shales are dominant around the Permian-Triassic boundary. Pelagic carbonate sedimentation gradually recovers from the Smithian onward. The Permian of the Karakorum is the sedimentary evidence of the passive margin of a lithospheric block, detached from the Gondwana continent during the Permian, that will later migrate towards the centre of the Paleo-Tethys, along with other lithospheric blocks of the Mega Lhasa plate.

CHITRALINA UNDULATA GEN. N. SP. N. (FORAMINIFERIDA) FROM THE LATE PERMIAN OF KARAKORUM (PAKISTAN)

Chitralina undulata gen. n. sp. n. (Foraminiferida) has been found for the first time in the Permian successions of Karakorum (Pakistan). Biostratigraphic analysis based on fusulinids, brachiopods, conodonts and small foraminifers pointed out that Chitralina undulata gen. n. sp. n. occurs from the Kubergandian to the Late Murgabian-Midian. Morphologically, Chitralina undulata gen. n. sp. n., is comparable to Rectostipulina quadrata Jenny-Deshusses, 1985, differing from it by means of the thickness and composition of the test and for the presence of marked longitudinal costae. The stratigraphic range of Rectostipulina quadrata spans the Midian-Dorashamian time-interval. The new genus Chitralina is very similar to the Permian genus Giraliarella Crespin, differing from it by means of the absence of transverse growth constrictions. The new family Chitralinidae fam. n., is also described herein.