Givetian, Frasnian and Famennian limestones from southern China contain microfossils generally regarded as calcified algae and cyanobacteria. These are present in 61 out of 253 sampled horizons in four sections from three widely spaced localities in Guangxi and southern Guizhou. Three of the sections sampled are Givetian-Frasnian-Famennian; one section is Frasnian-Famennian. They include reef and non-reef carbonates of shallow marine platform facies. The following taxa are identified with differing degrees of confidence, and placed in algae, cyanobacteria or microproblematica. Algae: Halysis, ‘solenoporaceans’, Vermiporella. Cyanobacteria: Bevocastria, Girvanella, Hedstroemia, Subtifloria. Microproblematica: ?Chabakovia, Garwoodia, ?Issinella, Izhella, Paraepiphyton, Rothpletzella, Shuguria, ?Stenophycus, Tharama, Wetheredella. As a whole, the abundance of algae, cyanobacteria and microproblematica increases by 34% from Givetian to Frasnian, and declines by 63% in the Famennian. This secular pattern of marked Famennian decrease does not support recognition of them as “disaster forms” in the immediate aftermath of late Frasnian extinction. Nonetheless, their survival into the Famennian could indicate tolerance of environmental stress, independence of changes in food supply, morphologic plasticity, and ability to occupy a range of habitats and depths. Uncertainties concerning the affinities of the problematic taxa hinder assessment of their significance.

The Welton Member of the Scotch Grove Formation at Shaffton Quarry, near Camanche, Iowa, is about 427 Ma old and contains numerous metaconulariid specimens, many of which are preserved in apex-downward orientation. Some of these show an unusual, splayed, “Maltese cross” configuration. Apex-downward configurations suggest rapid burial, consistent with the soft part preservation known in other taxa from this locality. The abundance of Metaconularia at Shaffton Quarry, and of topotype specimens of M. aspersa, the generic type species, permits evaluation of the degree of individual and intracollectional variation in peridermal ornament. Variation within and among individuals precludes reliance on ornamental differences in species differentiation in most cases. In view of these results we assign all Shaffton specimens to Metaconularia manni (Roy, 1935), and revise Metaconularia based on its type material from Europe and other material from Europe and North America. An exploratory phylogenetic analysis highlights aspects of character distribution within the genus, but the small number of characters states and possible taphonomic influences upon them limit confidence in the clade topology. Subgroups within the genus are characterized by larger, discoidal papillae, and by strong transverse corrugation and sinuous rows of smaller papillae. The genus itself comprises those conulariids with an external ornamentation of simple, round, small papillae, paired internal septae along the midlines, and a thin periderm that was to some degree pliable during life.

Carbonaceous bedded cherts of the late Neoproterozoic (Cryogenian) ∼800 to 750 Ma old Chichkan Formation of South Kazakhstan contain an abundant, diverse assemblage of exquisitely preserved microorganisms. Like many Proterozoic microbiotas, the Chichkan assemblage is dominated by prokaryotic cyanobacteria, both filamentous (oscillatorialeans and nostocaleans, represented primarily by cellular trichomes and empty sheaths) and coccoidal (chroococcaleans and pleurocapsaleans, including solitary, colonial, and stalk-forming specimens). However, unlike Proterozoic microbiotas reported from peritidal settings, the Chichkan fossils, permineralized in cherts deposited in the open shelf facies of the formation, include diverse microscopic eukaryotes: vase-shaped testate amoebae, spiny (acanthomorphic) phytoplanktonic unicells, large (up to ∼1 mm diameter) megasphaeromorphic acritarchs, and sausage-shaped vaucheriacean green alga-like filaments.

Given the composition of this biota and the presence in it and similarly aged assemblages of numerous taxa typical of late Neoproterozoic deposits (e.g., Cerebrosphaera, Jacutianema, Melanocyrillium, Stictosphaeridium, Trachyhystrichosphaera, and Vandalosphaeridium), the Chichkan Lagerstätte appears representative of the Cryogenian biota as now known, thereby documenting the status of the marine biosphere at a time closely preceding the radiation of the Metazoa. As such, we interpret this and other coeval mixed assemblages of prokaryotic and eukaryotic microfossils as representing an evolutionary stage transitional between the predominantly prokaryote-dominated Precambrian and the eukaryote-dominated Phanerozoic biospheres.

As reported here, the Chichkan assemblage is composed of 39 taxa (of which two forms are described informally) that are assigned to 23 genera of microscopic prokaryotes and eukaryotes and that include two new species: Polybessurus crassus n. sp. and Vandalosphaeridium koksuicum n. sp.

Arthrodendron maguricum n. sp. is described from deep-sea flysch of the lower Eocene Życzanów Conglomerate Member of the Szczawnica Formation (Magura Unit) in the Polish Carpathians. Arthrodendron maguricum is a larger agglutinated foraminifer showing regular, tubular chambers that may branch dichotomously. Its wall is tripartite and composed of an outer organic-rich layer, a main agglutinated layer, and an internal organic-rich layer. The organism evidently lived as epibenthos on the muddy sea floor. Because of their branching morphology and comparatively large dimensions, larger agglutinated foraminifera of the genus Arthrodendron have previously been confused with algae and trace fossils. Care should be taken in such cases to resolve the agglutinated wall and chambers of this deep-water agglutinated foraminifer. Arthrodendron maguricum displays superficial similarities to some modern komokiaceans, especially to Septuma. Further investigations are needed for clarification of their affinities and possible taxonomic consequences.

A revision of the Early-Middle Miocene anguine, Pseudopus laurillardi (Lartet, 1851), is presented based on a detailed anatomical analysis of one newly discovered articulated specimen and numerous disarticulated cranial and postcranial elements from several localities in Germany, as well as on the restudy of the original skeletal material of Lartet. the articulated specimen represents the first record of an articulated anguine from the Neogene. We demonstrate that the contemporaneous anguine Propseudopus fraasii (= Pseudopus fraasi, Pseudopus moguntinus or Ophisaurus moguntinus) from Germany and elsewhere in Europe represents a junior synonym of P. laurillardi. Three species of Pseudopus can by discriminated in the Cenozoic of Eurasia: P. laurillardi (Early-Middle Miocene of Europe), P. pannonicus (Late Miocene-Middle Pleistocene of central and eastern Europe) and P. apodus (Late Pleistocene-Recent, from Eastern Europe to central Asia). Eleven morphological characters of the skull have been identified that distinguish Pseudopus laurillardi from P. pannonicus and P. apodus. Four of these characters regard the frontal and parietal bones, whereas all other characters regard the dentary and dentition. the genus Pseudopus represents the largest and most robust taxon in the subfamily Anguinae and first occurs in central Europe at the beginning of MN 4 (~18.5 Ma). in contrast to the extant species, P. apodus, the fossils P. laurillardi and P. pannonicus had a greater ecological plasticity and lived in various types of environments. the fossil remains of these taxa are most frequently found in localities characterized by sub-humid to humid climate, which may indicate that their preferential habitats include forested environments.

A large, edrioasteroid-bearing hardground surface from the base of the Bellevue Member of the Grant Lake Formation near Maysville, Mason County, Kentucky is described. Four species are represented including Streptaster vorticellatus (Hall), Carneyella ulrichi Bassler and Shideler, Carneyella pilea (Hall), and Curvitriordo stecki n. sp. Specimens of S. vorticellatus and C. pilea add little to the known morphologies of these species. However, prior to this study C. ulrichi was known from the unique holotype, and Curvitriordo stecki n. sp. adds greatly to out understanding of Curvitriordo which was previously known from two species comprising three poorly preserved specimens. Curvitriordo stecki shows a bimodal size frequency distribution suggesting seasonal breeding whereas Carneyella ulrichi shows a left skewed size frequency suggesting low juvenile mortality. Streptaster vorticellatus shows a tight unimodal size frequency distribution suggestive of a single spat fall accumulation.

A phylogenetic analysis and review of Paleozoic phyllocarid systematics is presented using morphology-based characters from Cambrian to modern taxa. The resulting cladograms of the Phyllocarida suggest that the suborder Ceratiocaridina as traditionally defined (families Ceratiocarididae and Caryocarididae) is paraphyletic. Caryocarididae is subsequently elevated to subordinal rank with the erection of Caryocaridina n. suborder, resulting in two monophyletic suborders. Haplocaris n. gen. is erected to contain Caryocarididae taxa without triangular spine-like projections of the anterior telson margin. Emended diagnoses, quantified with morphometrics where appropriate, are integrated into this analysis, and result in synonymy of many Cambrian—Silurian caryocaridids and ceratiocaridids with pre-existing taxa. Two representatives of the Leptostraca are included in this analysis. A visual key of well-established representatives of the Ceratiocaridina is presented and suggestions are offered that will help to improve the long-term stability of the Archaeostraca.

The Batocrinidae was a component of the North America Early Mississippian crinoid fauna and a significant contributor to the global biodiversity spike referred to as the “Age of Crinoids.” All batocrinids are North American, and all but one species are confined to the Tournaisian and Visean. In this contribution, genera are objectively defined on discrete characters, and the generic assignment of all valid species is re-evaluated. A phylogenetic hypothesis is presented for relationships within the Batocrinidae based on parsimony-based analyses and known stratigraphic ranges.

Fifteen basic batocrinid architectural designs are recognized as genera, and four new genera are described: Glannearycrinus n. gen., Gongylocrinus n. gen, Magnuscrinus n. gen., and Simatocrinus n. gen. Batocrinus was a catch-all genus for any Mississippian camerate with tetragonal first primibrachials and an anal tube; thus, many late 19th century species are in need of a modern generic assignment. In this contribution, 61 percent of the 166 currently valid batocrinid species are reassigned to different genera. In addition, Sunwaptacrinus is transferred to the Batocrinidae, six species are transferred out of the Batocrinidae, and five species are designated as nomina dubia.

Precambrian microbiotas, such as that permineralized in bedded and stromatolitic cherts of the late Neoproterozoic, 750- to 800-Ma-old, Chichkan Formation of South Kazakhstan, have traditionally been studied by optical microscopy only. Such studies, however, are incapable of documenting accurately either the three-dimensional morphology of such fossils or their chemical composition and that of their embedding minerals. As shown here by analyses of fossils of the Chichkan Lagerstätte, the solution to these long-standing problems is provided by two techniques recently introduced to paleontology: confocal laser scanning microscopy (CLSM) and Raman imagery. The two techniques are used together to characterize, in situ and at micron-scale resolution, the cellular and organismal morphology of the thin section-embedded organic-walled Chichkan fossils. In addition, Raman imagery is used to analyze the molecular-structural composition of the carbonaceous fossils and of their embedding mineral matrix, identify the composition of intracellular inclusions, and quantitatively assess the geochemical maturity of the Chichkan organic matter.

CLSM and Raman imagery are both broadly applicable to the study of fossils, whether megascopic or microscopic and regardless of mode of preservation, and both are non-intrusive and non-destructive, factors that permit their use for analyses of archived specimens. They are especially useful for the study of microscopic fossils, as is demonstrated in this first in-depth study of diverse taxa of a single Precambrian microbiota for which they provide information in three dimensions at high spatial resolution about their organismal morphology, cellular anatomy, kerogenous composition, mode of preservation, and taphonomy and fidelity of preservation.

Late Givetian and early Frasnian conodont communities with Icriodus subterminus have been revised on the basis of collections from Iowa (USA), the Boulonnais and the Ardennes (northern France and Belgium), the Radom-Lublin area and Holy Cross Mountains (Poland), and the Ma'der-Tafilalt region (southeast Morocco). As a result an Icriodus subterminus Zone with a threefold subdivision is defined. The three subzones correspond approximately to the “Lower and Upper subterminus Fauna” and the “insita Fauna” commonly used in N America for the study of shallow-water platform carbonate successions.

The base of the subterminus Zone corresponds to a level within the uppermost part of the hermanni Zone; the top is characterized by the occurrence of the earliest Ancyrodella taxa, Montagne Noire Zones MN 1 and the base of MN 2 or slightly above the base of the falsiovalis Zone.

The diagnosis of Icriodus subterminus is amended and two morphotypes are recognized. The stratigraphic range of the alpha morphotype is confined to an interval between the uppermost part of the hermanni Zone and the top of the MN 3 Zone; the beta morphotype may range into the MN 6 Zone.

The holotype of Icriodus subterminus from the North Liberty beds in Iowa is most likely a specimen that was reworked from the Cedar Valley Limestone. Icriodus cedarensis and Icriodus tafilaltensis are described as new species, and the diagnoses of Icriodus excavatus and Icriodus expansus are amended. Between the Icriodus difficilis and Icriodus symmetricus zones, an Icriodus expansus Zone is defined.

The Cretaceous record of the shallow-marine margaritine gastropod genus Atira Stewart, 1927 in the region extending from Vancouver Island, to northern Baja California is studied in detail for the first time. It is represented by A. popenoei n. sp. (late Turonian to earliest Campanian), A. ornatissima (Gabb, 1864) (latest Santonian to late Campanian or possibly early Maastrichtian), and A. inornata (Gabb, 1864) (“mid” Maastrichtian), which is the youngest known species of Atira.

Atira originated in the tropical waters of the Tethys Sea in western Europe as early as the Early Cretaceous, possibly during the Hauterivian but was present there by the late Aptian to early Albian. The genus subsequently immigrated to other regions and became adapted to warm-temperate waters. By the late Turonian it had migrated westward to northern California. During the Campanian it reached south Sakhalin and in the earliest Maastrichtian it was present in southwest Japan. Although Atira? nebrascensis (Meek and Hayden, 1856) has been questionably reported from Campanian to “mid” Maastrichtian deposits in the Wyoming area of the Western Interior Basin, this species does not belong in genus Atira.

Cyriacotheriidae are a family of unusual small-bodied pantodonts known from the Paleocene of the Western Interior of North America. Cyriacotheriids possess a suite of dental characters similar to that of pantodonts (e.g., molar dilambdodonty, lingual molar hypoconulids), as well as several divergent features (e.g., molarized premolars, strong molar conules) that have been interpreted as “dermopteran-like.” the unusual combination of pantodont and dermopteran-like characters, combined with a limited fossil record, has made attempts at understanding the broader relationships of Cyriacotheriidae difficult. This paper reports on a new genus and two new species of cyriacotheriids from the Paleocene of Alberta, Canada, with both species significantly older than those of the only previously described cyriacotheriid, Cyriacotherium. Collectively, the dentitions of these new taxa exhibit derived characters seen in Cyriacotherium (e.g., robust molar conules, strong molar dilambdodonty) in addition to a number of plesiomorphies seen in more basal pantodonts (e.g., conspicuous molar entoconids, deep premolar ectoflexus) and, importantly, posterior premolars that are weakly molariform and non-dilambdodont. A phylogenetic analysis of the new cyriacotheriid, basal pantodonts, dermopterans, and dermopteran-like eutherians resulted in Cyriacotheriidae nesting within a monophyletic Pantodonta. the results strengthen previous hypotheses regarding the pantodont affinities of the family, and suggest that the dermopteran-like features seen in the more derived Cyriacotherium were acquired convergently. Although the discovery of new cyriacotheriids sheds light on the evolutionary history of the family, it cannot resolve the ongoing questions of pantodont origins; nonetheless, their discovery in strata of early Paleocene age indicates that significant parts of the evolutionary history of Cyriacotheriidae, and North American pantodonts more generally, have yet to be discovered.

New and old species and genera of the family Guadalupiidae (spherulitic hypercalcified demosponges of the order Agelasida) are described or redescribed from the West Texas Permian. The entire family is reviewed and observations are made on the epibionts, growth patterns, functional morphology, ecological relationships, morphologic variability, modular structure, and evolutionary history of these largely reef-dwelling sponges. The stratigraphic distribution of species is also noted; many are limited and can define zones. The new genera Exovasa and Incisimura and the new species Guadalupia auricula, G. cupulosa, G. ramescens, G. microcamera, G. vasa, Cystothalamia megacysta, Lemonea simplex, Incisimura bella, and Exovasa cystauletoides are described. Almost all previously published taxa are redescribed and in some cases redefined. The Guadalupiidae are unique among hypercalcified sponges in having a modular thalamid layer (thalamidarium) covered on the exhalant surface by a non-modular stromatoporoid-like layer (trabecularium).

The camerates, Pycnocrinus argutus (Walcott, 1883) and Rhaphanocrinus subnodosus (Walcott, 1883), are characterized by narrow food grooves. An open distal stem coil was present in P. argutus, and R. subnodosus may have possessed the same type of holdfast. Such holdfasts either lay loose on the seafloor or were wrapped around unknown soft objects. The rhaphanocrinids were located at elevations of at least 300 mm above the substrate. Conversely, the much smaller pycnocrinids lived close to the seafloor at levels of about 10 to 24 mm. The three cladids are Merocrinus curtus (Ulrich, 1879), M. retractilis (Walcott, 1883), and Dendrocrinus gregarius Billings, 1857a. Merocrinus typus Walcott, 1883 and M. corroboratus Walcott, 1883 are conspecific with M. curtus. The spiral anal sac of M. retractilis is unique. Embryocrinus problematicus Hudson, 1918 probably represents a juvenile of Dendrocrinus gregarius, which also occurs in Ottawa, Ontario. Complete columns and attachment structures have not been found for D. gregarius and Merocrinus retractilis. Merocrinus curtus ranges from New York into the Cincinnati, Ohio area of the midcontinent. Although attachment devices and long stem segments are not preserved in the New York specimens, individuals of Merocrinus curtus from Cincinnati either have a conical holdfast cemented to a bryozoan or a tight distal stem coil that was wrapped around the stem of another crinoid; adult merocrinids from the Cincinnati region were positioned high above the seafloor, and incomplete stem segments up to about 800 mm long are known. The Walcott-Rust Quarry cladids all possessed wider food grooves than the camerates, so they were able to catch larger food particles.

Light microscopy studies on new materials and museum collections of early Cambrian organic-walled microfossils, informally called acritarchs, provide the observations on phenetic features that permit a comparison to certain Modern microalgae and the recognition of various developmental stages in their life cycle. the microfossils derive from various depositional settings in Estonia, Australia, Greenland, Sweden, and Poland. the exceptionally preserved microfossils reveal the internal body within the vesicle, the endocyst, and the process of releasing the endocyst from the cyst. Vegetative cells, cysts, and endocysts are distinguished, and the hypothetical reconstruction of a complex life cycle with the alternation of sexual and asexual generations is proposed. Acritarchs from the Skiagia-plexus are cysts, and likely zygotes in the sexual generation, which periodically rested as “benthic plankton.” Some microfossils of the Leiosphaeridia-plexus that are inferred to be vegetative cells were planktonic and probably haplobiontic. These form-taxa may belong to a single biological species, or a few closely related species, and represent the developmental stages and alternating generations in a complex life cycle that is expressed by polymorphic, sphaero- and acanthomorphic acritarchs. the morphological resemblance and diagnostic cell wall ultrastructure with the trilaminar sheath structure known from earlier studies suggest that the early Cambrian microfossils are the ancestral representatives and/or early lineages to the Modern class Chlorophyceae and the orders Volvocales and Chlorococcales.

During the Pliocene, the diversification of the tribes Lamini and Camelini of the Family Camelidae took place in most of North America, but at present in Mexico the systematics of Pliocene Camelidae are poorly known. Fossil material described in this paper was recovered from Blancan I and Blancan III age floodplain and point bar deposits of the San Miguel de Allende basin, Guanajuato state, central Mexico, which approximately spans a time frame from 4.7 to 3.0 Ma. The identified taxa include the lamines Hemiauchenia blancoensis (Meade) 1945, Hemiauchenia gracilis Meachen, 2005, Blancocamelus meadei Dalquest, 1975 and Camelops sp., while the camelines are represented by Megatylopus sp. The records of H. gracilis and B. meadei in the Pliocene of central Mexico are the oldest in North America. Previous studies of the probable feeding strategies of these taxa indicate that they were browsers or browser-like intermediate feeders and just one was an intermediate feeder. The records of these species in the Early Blancan of Guanajuato extend their geographic distribution from the southern USA to central Mexico.

We provide the first detailed systematic taxonomy and paleoecological investigation of late Paleozoic brachiopod faunas from Korea. Specifically, we focus on the brachiopods from the Geumcheon-Jangseong Formation, the lower part of the Pyeongan Supergroup in the Taebaeksan Basin. The formation yields a variety of marine invertebrate fossils, including brachiopods, molluscs, echinoderms, corals, fusulinids, and conodonts. Diverse brachiopods are described from six siliciclastic horizons of the formation at three localities, including 23 species belonging to 20 genera with two new species: Rhipidomella parva n. sp. and Stenoscisma wooi n. sp. Three brachiopod assemblages of the late Moscovian (Pennsylvanian) age are recognized based on their species compositions and stratigraphic distributions, namely the Choristites, Rhipidomella, and Hustedia assemblages. The brachiopod faunal composition varies within each assemblage as well as between the Assemblages, most likely reflecting local paleoenvironmental and hence paleoecological differences. The Choristites Assemblage includes relatively large brachiopods represented by Derbyia, Choristites, and Stenoscisma and may have inhabited open marine to partly restricted marine environments, whereas the Rhipidomella and Hustedia Assemblages consist of a small number of small-sized brachiopods living in lagoonal environments. The Choristites Assemblage shows a close affinity with Moscovian brachiopod assemblages in the eastern Paleo-Tethys regions, especially the Brachythyrina lata-Choristites yanghukouensis-Echinoconchus elegans Assemblage of North China, whereas the Rhipidomella and Hustedia assemblages both exhibit strong endemism.

Myzostome galls on arms of the Early Jurassic (Pliensbachian) Balanocrinus gracilis provide the first unequivocal evidence of such parasitic infestation in a post-Paleozoic crinoid.

Three new types of arthropod are described from Cambrian intertidal lithofacies of the Elk Mound Group and St. Lawrence Formation of Wisconsin and the Potsdam Group of Quebec. These arthropods are preserved ventrally in sandstone in life position and in three dimensions, allowing detailed characterization of limb morphologies, labrums, and other organs such as eyes. A taphonomic model is presented, illustrating this unusual, uncompressed, three-dimensional style of preservation. Arenosicaris inflata n. sp., from the Terreneuvian-Furongian Elk Mound Group and the Furongian St. Lawrence Formation, is the earliest unambiguous occurrence of a malacostracan phyllocarid. This 3 cm long arthropod had ovate valves, five pairs of biramous pleopods, and at least 3 pairs of thoracopods. Mosinieia macnaughtoni n. sp., a large (>10 cm long) euthycarcinoid of uncertain affinity with flattened or paddle-like appendages also occurs in Elk Mound strata. Mictomerus melochevillensis n. sp. represents a new euthycarcinoid family and is the first known non-trilobite arthropod from the middle Cambrian-Furongian Potsdam Group of Quebec. M. melochevillensis n. sp. is large (8–10+ cm long), with as many as eleven pairs of well-preserved homopodous, uniramous, non-paddle-like limbs. Both M. macnaughtoni and M. melochevillensis differ substantially from previously known euthycarcinoids in limb morphology and represent the oldest known representatives of the group. Additionally, both M. melochevillensis n. sp. and M. macnaughtoni n. sp. possess morphologies that are consistent with abundant subaerial and subaqueous Diplichnites and Protichnites trackways known from these units, suggesting that these may be the earliest land-going animals.

Rudists are a principal biotic component of Cretaceous carbonates in Tibet and in the Western Tarim Basin. Barremian to Maastrichtian carbonate units are widespread on the northern margin of the Indian Plate and in Tethyan tectonic slices that were welded onto Eurasia in successive stages during the Late Cretaceous and Paleogene. In far northwestern Tibet, Barremian-Cenomanian endemic rudists and cosmopolitan orbitolinid foraminifera occupied isolated carbonate platforms in the eastern Tethys. Rudists, corals, and stromatoporoids composed bioherms up to 10 m thick and several kilometers in lateral extent. A unique endemic requieniid rudist, Rutonia, is compared to morphologically similar but older, less derived genera. Associated specimens in this assemblage are indeterminate requieniid valves, monopleurids, and two genera with three radiolitid species that are re-described and taxonomic positions re-evaluated. In southern Tibet, mainly endemic Campanian-Maastrichtian radiolitid rudists and cosmopolitan larger benthic foraminifera contributed to carbonate shelves on the northern Indian Plate near the Cretaceous equator. In the Western Tarim Basin Cenomanian strata yield Tethyan rudist species.

Coiling morphometric analysis using the three-dimensional morphology Raup diagram shows that Requieniidae valves in contact with the substrate are convergent with the basic gastropod shell. More derived strongly coiled, younger requieniids were adapted to encrusting or semi-infaunal habits. Stratigraphic analysis confirms that Requieniidae diversity crises coincided with Cretaceous oceanic anoxic events

Two end members of valve geometry each appear to be primitive and derived characters respectively and separate the family Requieniidae into two clades that are here recognized as two new subfamilies. The end members are defined by the coiling geometry, whether the spire is close to the plane of commissure or it is translated along the coiling axis and by myophore structures. The older matheroniform clade has a low spirogyrate LV that is translated slightly from the commissure along the coiling axis; this group is composed of Matheronia (and its subgenus Monnieria), Hypelasma, Lovetchenia, Rutonia, and Kugleria. Genera in the younger clade have a tall trochospiral LV that is translated along the coiling axis and consists of Requienia, Toucasia, Pseudotoucasia, Apricardia, Bayleoidea, and Bayleia. Claditics support these relationships.