Brachiopod Genera Research Articles

New Middle Carboniferous genus Neotornquistia (Brachiopoda, Chonetida) from the Moscow Syneclise

A new Middle Carboniferous brachiopod genus, Neotornquistia, with the type species Paeckelmannia aljutovica E. Ivanova, 1952 (order Chonetida, superfamily Anoplioidea, family Anopliidae, subfamily Tornquistiinae) is described from the Alyutovo Formation of the Vereyan Horizon of the Moscovian Stage of the Moscow Syneclise.

The earliest known Stegerhynchus (Rhynchonellida, Brachiopoda) from the Hirnantian strata (uppermost Ordovician) at Borenshult, Östergötland, Sweden

Stegerhynchus eoborealis sp. nov. from the Dalmanitina Beds (Hirnantian, uppermost Ordovician), Borenshult, Östergötland, Sweden, is described in this study as the earliest known species of Stegerhynchus, within the family Rhynchotrematidae. This implies that Stegerhynchus originated during the latest Ordovician mass extinction event, and radiated in the Silurian Period to become one of most common rhynchonellide brachiopod genera in shallow tropical seas. In the early evolutionary stage of the genus, Stegerhynchus eoborealis already exhibited a notable reduction in the size of septalium compared to the closely related genus Rhynchotrema. Compared to its Silurian counterparts (e.g. Stegerhynchus borealis and S. peneborealis), Stegerhynchus eoborealis has some variable characters within single populations, particularly in the number of costae in the sulcus and on the fold, implying a morphological plasticity during the early evolutionary stage of the genus. During the Hirnantian mass extinction events, five rhynchonellide families were represented by small taxonomic groups, but only the Rhynchotrematidae and Trigonirhynchiidae diversified into many highly successful clades of rhynchonellides during the Silurian and Devonian. However, the Ancistrorhynchidae, Orthorhynchulidae, and Sphenotretidae largely disappeared by the end of the Ordovician, with a few species (such as Plectothyrella sp.) surviving into the earliest Silurian but shortly becoming extinct.

Onshore migration of a deep-water brachiopod fauna from the Lower Ordovician Tonggao Formation, Jiangnan Slope, southeastern Guizhou Province, South ChinaThis article is one of a series of papers published in this Special Issue on the theme The dynamic reef and shelly communities of the Paleozoic. This Special is in honour of our colleague and friend Paul Copper.

Brachiopods from the lower Tonggao Formation (Floian, late Early Ordovician) of Sandu, southeastern Guizhou Province, represent a deep-water benthic shelly fauna from the Jiangnan Slope facies of the South China paleoplate. The fauna contains 16 brachiopod taxa, with orthides, lingulates, and pentamerides being the common groups. Concurrent graptolites confine the brachiopod fauna to the Tetragraptus approximatus and the Acrograptus filiformis biozones (early Floian). The first appearance datum (FAD) of several brachiopod genera, such as Paralenorthis , Protoskenidioides , and Nereidella , in the Sandu slope facies is one or two graptolitic biozones lower than their FAD in shallower water facies on the Yangtze Platform. Later in the late Floian, these genera became major components of the Sinorthis fauna that flourished over much of the Yangtze Platform, suggesting a migration of the benthic shelly fauna from slope to platform facies during the Floian radiation in South China. Compared to the platform fauna, the deep-water brachiopod fauna of the Sandu area has a lower level of richness, diversity, and community organization. Three brachiopod associations are recognized: the Paralenorthis–Nereidella, the Palaeoglossa longa , and the Lingulella –Protoskenidioides associations. An upsection decrease in shell size, faunal richness, and species diversity in the Tonggao Formation indicate a deteriorating environment towards hypersalinity in the Sandu area, resulting in the ultimate disappearance of the deep-water brachiopod fauna.

The dynamic reef and shelly communities of the Paleozoic / La nature dynamique des communautés récifales et coquillières du Paléozoïque

Shelly communities and reef ecosystems represent the pinnacle of generic diversity and organizational complexity in marine environments. These systems are sensitive to climatic, tectonic, eustatic, and catastrophic changes, and their evolution and extinctions help reveal the regional and global dynamics of the Paleozoic Earth. It is, therefore, not surprising that the fossil record of these ecosystems has commanded the attention of generations of researchers (e.g., Billings 1862; Ziegler 1965; Osgood 1970; and a large compendium of papers in Boucot and Lawson 1999 on paleocommunities and Kiessling et al. 2002 on reef ecosystems, such as Copper 2002 and Kiessling 2002), each with their own perspective on the dynamics of shallow-marine ecosystems. With a system approach to understanding these ancient environments in mind, it was our intention to bring together researchers of various disciplines — paleobiology, paleoecology, carbonate sedimentology, taphonomy — to present a broad yet integrated perspective on recent advances in the field of shelly communities and reef ecosystems. This special issue is a collection of papers presented at Topical Session 114 convened at the 2006 Annual Meeting of the Geological Society of America (GSA) in Philadelphia, held in honour of Dr. Paul Copper’s retirement as Professor at Laurentian University (Sudbury, Ontario, Canada). The session included researchers working on a variety of deposits, addressing different questions, but with a unified theme to explore the temporal and spatial patterns and evolution of Paleozoic shallow-marine benthic shelly and reef communities. The theme of the topic session, as well as the proceedings papers in this special issue, is very much in keeping with Paul Copper’s research career, almost equally divided between Paleozoic brachiopods and reef communities. The contributors to this volume all feel some close connection to Paul’s academic activities, either as his former graduate students, research associates, or colleagues; some of us have benefited greatly from both scientific discussions with him or from his enormous fossil collections. The articles in this issue (cited in bold) cover various aspects of Paleozoic level-bottom shelly communities and reef paleoecology. Ma et al. give a detailed account of the internal structures in the well-known and widespread Late Devonian brachiopod genus Desquamatia from Bergisches Land of Germany. This fundamental morphological study is crucial for understanding the autecology and synecology of this extremely common atrypid genus and its abrupt extinction near the end of the Devonian. Hollis and Ausich study the functional morphology of a top-tier crinoid and reinterpret its anchoring mechanism as a distal coil capable of wrapping around other crinoid columns. Zhan and Jin document a case of brachiopod migration from an upper slope setting to the Yangtze Platform in South China during the Early Ordovician. The upslope dispersal subsequently led to the development of distinct brachiopod communities and faunas of the Yangtze Platform. This study shows a relatively deepwater origin of some common brachiopod communities of the Yangtze Platform, as well as the pioneer stage of brachiopod community organization during the Early Ordovician. Jin discusses the temporal and spatial differentiation of Early Silurian pentameride brachiopod communities of Anticosti Island using multivariate analyses, and demonstrates that the Pentamerus and stricklandiid communities had largely overlapping overall ranges in terms of their water depth and water turbulence level, but stratigraphically, the two groups of communities were rather clearly segregated — a paleoecological pattern probably controlled by fluctuating oceanic water temperature. Continuing the theme on Anticosti paleontology, Li and Allen use a unique approach to explore the relationships between orthide brachiopod associations and their living environments in the Anticosti Basin during the Early Silurian, and Tapanila and Ebbestad explore a miniature island community, hosted on a large gastropod shell. Analysis of the overlapping relations of encrusters, borers, and symbiotic embedders provides a remarkable example of the spatial forcing that may have played an important evolutionary role in muddy-bottom environments. Daley provides a broad survey of the boring patterns in various types of brachiopod shells from the Late Ordovician to the Early Devonian. She uses a series of techniques to differentiate post-mortem Received 27 November 2007. Accepted 13 December 2007. Published on the NRC Research Press Web site at cjes.nrc.ca on 4 March 2008.

Co-existence of interarea and palintrope: contribution of a new pentameride brachiopod from the Upper Ordovician of Sweden

ABSTRACTA new genus of pentameride brachiopod, Costilamnulella, described herein from the middle Ashgill of Sweden, is particularly interesting in that the ventral valve possesses both an interarea and a palintrope. Brachiopods normally have one or the other, but both structures do occur amongst the pentamerides, e.g. in Clorinda, Anastrophia and Brevilamnulella. The presence of these structures in three separate pentameride families indicates the persistence of the more primitive condition of an interarea whilst the more advanced palintrope is becoming established. Costilamnulella is interpreted as a restricted side line of the main development of the more widely occurring Brevilamnulella, which survived the end-Ordovician event and may have shared its ancestry with the ubiquitous Clorinda.

Comparison of the Crystallographic Structure of Semi Nacre and Nacre by Electron Backscatter Diffraction

Aragonite nacre is commonly found in the shells of molluscs, while semi nacre has been observed in the shells of organisms from two phyla: the Brachiopoda and the Bryozoa. Calcite semi nacre and aragonite nacre display similar morphologies with laminae composed of tablets that grow by screw dislocation. This study uses electron backscatter diffraction to compare the crystallography of calcite semi nacre from the shell of the Craniid brachiopod Novocrania huttoni with aragonite nacre from the shell of the bivalve mollusc Mytilus edulis. Semi nacre and nacre are similar in morphology but ultimately have different crystallography. In N. huttoni calcite semi nacre, the c-axis lies parallel to the laminae of the secondary layer of the shell. In comparison, the c-axis of aragonite nacre in M. edulis is orientated perpendicular to the laminae. The crystallography of calcite semi nacre in the secondary layer of N. huttoni is similar to the crystallography of skeletal ultrastructures produced by bryozoans, while it differs from the crystallography described in other brachiopod genera.

A spinose stem group brachiopod with pedicle from the Middle Cambrian Burgess Shale

AbstractA new genus and species of a Middle Cambrian stem group brachiopod, Acanthotretella spinosa n. gen. and n. sp., is described from the Burgess Shale Formation. Most of the 42 specimens studied came from the Greater Phyllopod bed (Walcott Quarry) and were collected from five bed assemblages, each representing a single obrution event. Specimens are probably preserved within their original habitat. In contrast to all brachiopods known from the Burgess Shale, the shells of the new stem group brachiopod are often deformed and do not show signs of brittle breakage, which suggests that the valves were originally either entirely organic in composition or, more likely, had just a minor mineral component. Acanthotretella spinosa differs from all the other described Cambrian brachiopods in that it is covered by long, slender and possibly partly mineralized spines that are posteriorly inclined at an oblique angle away from the anterior margin. The spines penetrate the shell and are mainly comparable with the thorn‐like organic objects that have been inferred from early siphonotretoid brachiopods. The pedicle was slender and was composed of a central coelomic region and emerged from an apical foramen at the end of an internal pedicle tube. The finding of a pedicle attached to the macrobenthic algae Dictyophycus and other epibenthos implies that A. spinosa did not have an infaunal mode of life. The visceral region and interior characters are poorly preserved.

Palaeobiogeographical affinities of the Argentine Precordilleran Late Palaeozoic brachiopod faunas

Precordilleran Late Palaeozoic brachiopod genera considered for this palaeobiogeographical analysis belong to four faunal associations: the low diversity Early Carboniferous (Tournaisian) Protocanites scalabrinii-Azurduya chavelensis Zone; the Late Carboniferous (Bashkirian-Moscovian) Levipustula fauna, which appears in sequences associated with glacial intervals; the latest Carboniferous-earliest Permian (Gzhelian-Asselian) Rhipidomella-Micraphelia and Tuberculatella-Aseptella associations, and the Early Permian (mid to late Asselian) Tivertonia jachalensis-Streptorhynchus inaequiornatus Biozone. The brachiopod affinities of the Precordillera are compared with the biogeographical Late Palaeozoic regions previously suggested by other authors using cluster analysis. During the Bashkirian-Moscovian, the Precordilleran faunas show a high affinity with the Austral Realm because of the presence of the Levipustula faunal elements in Eastern Australia. At the same time the affinity with the central and North American Regions is very low. The Early Permian Precordilleran faunas demonstrate highest affinity with the Gondwanan Realm with several genera also linked to the Tethyan and Boreal Realms. After the Late Carboniferous glacial episodes that affected the southwestern Gondwanan margin, the Precordilleran region underwent climatic amelioration. Subsequently, the Early Permian Precordilleran brachiopod assemblages are characterized by typical cool to cold water genera widely developed in the core Gondwanan Realm, with fewer genera (such as Kochiproductus, Rhynchopora and Neochonetes) suggesting a warmer water influence. The Precordilleran faunas demonstrate an increase in brachiopod diversity from the Carboniferous to the Permian, related to water temperature changes and to the palaeogeographical evolution of the southwestern Gondwanan margin and the movement of Gondwana across the South Pole.

Lower Devonian vertebrates, arthropods and brachiopods from northern Vietnam

Additional vertebrates and ostracods from the bituminous shale of the Khao Loc Formation at Tong Vai, Ha Giang Province, northern Vietnam, corroborate its correlation with the upper part of the Xishancun (Xiaxishancun) Formation and the lower part of the Xitun and Lianhuashan formations of South China, and its Middle to Late Lochkovian age. The variations in morphology and ornamentation of the galeaspid Polybranchiaspis liaojaoshanensis from Tong Vai are discussed and regarded as possibly size and growth-related. A new acanthothoracid placoderm with a very deep dorsal process is described from Tong Vai and the specific distinction between the antiarchs Minicrania lissa from Tong Vai and M. lirouyii from Yunnan is supported by additional characters. Petalichthyid placoderms are recorded from this locality for the first time, and the skull of a juvenile youngolepidid sarcopterygian is described. Eurypterid fragments and a phyllocarid crustacean are also recorded from the Khao Loc Formation. A new species of the chonetid brachiopod genus Tulynetes, endemic to northern Vietnam, is described from the Pragian Mia Le Formation at Cu Le, Bac Kan Province, a new locality which yields a large diversity of taxa with outstanding preservation.

Biofacies analysis of Hettangian-Sinemurian bivalve/brachiopod associations from the Neuquén Basin (Argentina)

Based upon extensive sampling with strict stratigraphical control on Hettangian and Sinemurian deposits cropping out at the river Atuel region (southwest Mendoza Province), the presence of all bivalve and brachiopod genera was recorded. Data gathered from the analysed interval were processed by multivariate analysis and the resulting Q-mode dendrogram was used to discriminate five associations (i.e. Entolium-limoids, Pholadomya-Pinna-Pleuromya, Weyla-Gryphaea, Lywea and Cardinioides). These are not in simple stratigraphical succession but are recurrent, reflecting palaeosynecological and biofacies influences. The palaeoenvironmental implications of these associations are analysed, as well as their geographical and stratigraphical distributions in the studied sections (Arroyo Malo, El Pedrero and Las Chilcas). The Cardinioides association is controlled by palaeosalinity and corresponds to a paralic/estuarine environment, of restricted geographical and stratigraphical distribution, whereas the remaining associations correspond to normal marine shelf to littoral environments. The Lywea association is interpreted as allochthonous and probably an impoverished subset derived from the diverse Weyla-Gryphaea association. On the basis of the palaeoautecological characteristics of the taxa involved in terms of guilds represented in these benthonic associations, it is concluded that most of the associations were dominated by the epifauna, whereas in the Pholadomya-Pinna-Pleuromya association the infauna and semi-infauna were particularly conspicuous and diverse, and the Cardinioides association was characterized by shallow infauna. Typical basinal biofacies from deeper, off-shore environments, and fresh-water biofacies, are both missing.

Middle Permian Brachiopods from Greece and their palaeobiogeographical significance: New evidence for a Gondwanan affinity of the Chios Island upper unit

Synopsis Wordian (Middle Permian) brachiopods from the allochthonous Upper Unit of Chios (Greece) are described and used to perform a palaeobiogeographical analysis to establish the pa‐laeogeographicalaffinities of the unit. Species of the genera Stenoscisma Conrad, 1839, Cleiothyridina Buckman, 1906, Martinia McCoy, 1844 and Dielasma King, 1859 are reported for the first time from Chios and their systematic descriptions are given. In addition, the revision and discussion of the genus Kotlaia Grant, 1993 and its comparison with Orthotichia Hall & Clarke, 1892 are provided in the systematic section. A matrix of presence/absence data of Wordian (Middle Permian) brachiopod genera from Crimea, Sosio, Oman, Chios, the Salt Range and Timor was analysed using multivariate methods. Cluster analysis, principal coordinate analysis, non‐metric multidimensional scaling, minimum spanning trees and bond analyses indicate a similarity between Chios and the Gondwanan data sets of Oman and the Salt Range. However, maximum dissimilarity is recorded when comparing Chios to the Crimean brachiopod faunas. This indicates a clear Gondwanan affinity of the Wordian brachiopods of the Upper Unit of Chios.

A new Platystrophia-like brachiopod genus from the Ordovician Boda Limestone of Dalarna, Sweden

A new orthide brachiopod Siljanostrophia jaanussoni gen. et sp. nov., is described from the Ashgill Boda Limestone of the Siljan district, Dalarna, Sweden. The spirifer-like shell has remnants of dense, hollow spines and the ventral interior closely resembles Platystrophia King, 1850, but its cardinalia shows similarity to Gnamptorhynchos Jin, 1989, which has been assigned to the Platystrophiidae. This study indicates that the affinities of Siljanostrophia and Gnamptorynchos to the Platystrophiidae require further confirmation.

NAMURIAN FOSSILS (BRACHIOPODS, GONIATITES) FROM SATUN PROVINCE, SOUTHERN THAILAND

Abstract A previously unknown Namurian goniatite and brachiopod fauna is described from Southeast Asia. The goniatites provide new insights into their global distribution and the age of the fauna. Two new brachiopod genera, Eileenella Racheboeuf and Plicambocoelia Boucot and Brunton, and five new species are described. The brachiopod fauna is unlike any known previously from Asia.

Namurian fossils (brachiopods, goniatites) from Satun Province, southern Thailand

A previously unknown Namurian goniatite and brachiopod fauna is described from Southeast Asia. The goniatites provide new insights into their global distribution and the age of the fauna. Two new brachiopod genera, Eileenella Racheboeuf and Plicambocoelia Boucot and Brunton, and five new species are described. The brachiopod fauna is unlike any known previously from Asia.

Discussion of the Early Devonian rhynchonellid brachiopod genus Borealirhynchia Su, 1976

The Early Devonian brachiopod genus Borealirhynchia was established by Su, 1976. Phylum Brachiopoda (Cambrian to Devonian). In: Paleontological Atlas of North China, Inner Mongolia Volume 1. Geological Publishing House Beijing, pp. 155–227 (in Chinese). It has not been previously described in detail, nor have transverse serial sections of the internal features of Borealirhynchia delerensis, the type species, been published. In this paper Borealirhynchia, along with a few species previously assigned to it, is analysed and discussed. Detailed transverse serial sections of the internal features of B.? lata Su, 1976, are provided, based on well-preserved specimens collected from the Lower Devonian strata of Dong Ujimqin Qi, northeastern Inner Mongolia. Borealirhynchia? gigantea Su, 1976 and Latonotoechia multicosta Su, 1976 are considered to be synonyms of B.? lata Su with the same external and internal characters present in all three species. Some Lower Devonian strata, in which Borealirhynchia was found and reported, from Dong Ujimqin Qi, northeastern Inner Mongolia, are fully described.

Biostratigraphical value of some Strunian (Devonian, uppermost Famennian) Productidina, Rhynchonellida, Spiriferida, Spiriferinida brachiopods

The space of Devonian time considered in this paper corresponds to the uppermost part of the Famennian or the latest Famennian as a fourfold subdivision of the stage, usually called by many authors Strunian in neritic facies and Wocklumeria Stufe or Wocklumian in pelagic facies. Here, we examine the biostratigraphical value of certain brachiopod genera and species as bio-markers of the uppermost Famennian throughout the world (Europe, the former USSR, Middle East, Asia, North America, North Africa, and Australia). We have focused our study for species which stratigraphical range has been firmly established in correlation with the conodont biozones (Upper expansa, Early, Middle and Late praesulcata), the ammonoid biozones (do VI = “ Wocklumeria Stufe”), or the foraminifera biozones ( kobeitusana Zone). Other data for which the stratigraphical range is not based on standard biozonation are provided in the annex. The brachiopod bio-markers discussed in this paper belong to 14 Productidina genera ( Acanthatia, Araksalosia, Ericiata, Hamlingella, Mesoplica, Nigerinoplica, Orbinaria, Ovatia, Rugauris, Semiproductus, Sentosia, Spinocarinifera, Steinhagella, Whidbornella), 7 Rhynchonellida genera ( Araratella, Centrorhynchus, Hadyrhyncha, Megalopterorhynchus, Novaplatirostrum, Rozmanaria, Tchanakhtchirostrum), 13 Spiriferida genera ( Brachythyris, Cyrtospirifer, Dichospirifer, Eochoristites, Imbrexia, Parallelora, Prospira, Rigauxia, Sphenospira, Tenisia, Toryniferella, Tylothyris, Voiseyella) and one Spiriferinida genus ( Syringothyris). Other orders have not been studied in this paper. The main features of the uppermost Famennian brachiopod taxa represented in this paper are commented. All these taxa are listed as completely as possible throughout the world (with complements in the annex). A quick summary of the geographic distribution of the more represented taxa is given in conclusion.

LATE CHANGHSINGIAN FAUNA OF THE NORTHWESTERN CAUCASUS MOUNTAINS, RUSSIA

Abstract Upper Changhsingian strata occur as isolated outcrops in the Malaya Laba and Belaya river basins in the Peredovoy Range of the northwestern Caucasus Mountains and include shelfal limestone, reefal and biohermal buildups, and terrigenous clastics, here placed in the Belalabinskaya Group. These lithofacies contain a varied and rich assemblage of brachiopods, bivalves, ammonoids, inozoan sponges, and algae. This biota is Late Changhsingian in age and correlates with similar biotas described in south China, the Pamir Mountains, South Primorye in far eastern Russia, and Transcaucasia. The brachiopod genera and biotic assemblages are very similar to those of the Cathaysian Subprovince of the Tethyan Province. Two new families, Labaellidae and Licharewiconchidae; four new genera, Labaella, Licharewiconcha, Tethysiella, and Nikitinia; a new diagnosis of Caucasoproductus; and four new species of brachiopods, Rhipidomella caucasica, Cathaysia caucasica, Nikitinia licharewi, and Licharewina praetriassica, a...

A new meristid brachiopod genus from the Lower Carboniferous of Guizhou, China

The rowleyellinae is a small subfamily of meristelloid athyridid brachiopods, previously with only one genus,RowleyellaWeller, 1911 (Alvarez and Brunton, 1995; Alvarez et al., 1998; Alvarez and Rong, 2002). In this paper we report a new meristelloid athyridid brachiopod genusMuhuathyrisfrom a newly discovered, very diverse Tournaisian brachiopod fauna in South China. It is noteworthy that this newly discovered fauna is slightly older than that reported earlier from the same outcrop (Balinski, 1999). A full discussion of the newly discovered fauna is currently in preparation. Morphological features ofMuhuathyrisn. gen. suggest that it is probably an evolutionary intermediate betweenCamarophorellaHall and Clarke, 1893 andRowleyellaWeller, 1911. The new genus differs fromCamarophorellaandRowleyellaonly in the nature of the structures beneath the septalium in the dorsal valve. InCamarophorellaa shoe lifter is present in front of or beneath the septalium. InRowleyellaa cruralium rests on the dorsal median septum under the septalium and extends to the front of septalium. Lateral to the dorsal median septum, two thin and short plates, asymmetrically disposed, are present posteriorly under the cruralium, which were considered by Carter (1991) as a very posteriorly placed shoe lifter. In the new genus a structure consisting of two plates lateral to the dorsal median septum is attached to the dorsal surface of septalium near the crural bases. This structure extends from the dorsal beak to the posterior of the adductor muscle fields. It may be developed as two vertical plates lateral to the median septum, or, when the plates converge medially, as a sessile or median septum-supported cruraliumlike platform. The structure primarily acts as support to the crural bases and septalium rather than a dorsal adductor muscle platform, but may also serve as part of dorsal adductor muscle attachments in some individuals. It seems probable that this structure might be homologous to the cruralium inRowleyella.For this reason we put the new genus within the subfamily Rowleyellinae.

Elliptical Fourier Functions as a Morphological Descriptor of the Genus Stenosarina (Brachiopoda, Terebratulida, New Caledonia)

The present-day brachiopod genus Stenosarina from New Caledonia, which comprises two species—S. globosa and S. crosnieri—and a third indented form known as lobate Stenosarina, has not been described in the literature. To investigate the morphological variability of the genus Stenosarina and to determine how the lobate form is related to the first two species, 57 specimens were studied by means of elliptical Fourier functions. Harmonics 2–11 were used as outline descriptors. The harmonics describing each outline and then their Fourier coefficients were compared using factor analysis. The study showed that Fourier functions provide accurate descriptors and allow for precise comparisons of brachiopod outlines. Moreover, harmonic coefficients were found to be more informative than harmonic amplitudes. The results revealed a marked morphological disparity within the genus Stenosarina. The lobate Stenosarina appeared to be morphologically closer to S. crosnieri than to S. globosaand may therefore be considered as an endemic variant of S. crosnieri.

A new siphonotretid brachiopod from the Silurian of central-western New South Wales, Australia

A new genus and species of Silurian siphonotretid brachiopod, Orbaspina gelasinus n.gen. and n.sp., is described from the late Llandovery ( amorphognathoides Zone) to early Wenlock (ranuliformis Zone) Boree Creek Formation of central-western New South Wales, Australia. This represents the first confirmed report of a post-Ordovician siphonotretid from east Gondwana. Other supposed post- Ordovician siphonotretid occurrences are reviewed. Higher-level taxonomic relationships between the Siphonotretida and other linguliformean groups are discussed; based on present knowledge, the siphonotretids appear closest to the lingulellotretids or dysoristids.