Famennian conodonts from the Hongguleleng Formation at the Bulongguoer stratotype section,western Junggar,Northwest China

The Hongguleleng Formation, the highest and most important Devonian marine carbonate horizon in western Junggar, contains an endemic shallow-water Icriodus–Polygnathus conodont fauna with rare palmatolepids and other genera. The conodont faunas from the Bulongguoer and the Wulankeshun sections are similar, with high abundance (about 40%) of endemic taxa (13 taxa), indicating isolation of the Junggar Basin during early Famennian. Non-endemic species in the faunas suggest that the Lower Member of the Hongguleleng Formation is assignable to the Pa. rhomboidea Zone to the Pa. marginifera marginifera Zone of early Famennian, not including the Frasnian–Famennian boundary. The Upper Member may be of late Famennian–early Tournaisian in age on the basis of our preliminary faunal analysis.     

Analysis of asymmetries in the African fruit bats Eidolon helvum and Rousettus egyptiacus (Mammalia: Megachiroptera) from the islands of the Gulf of Guinea. I. Variance and size components of bilateral variation

A set of cranial characters was examined in the fruit bats Rousettus egyptiacus and Eidolon helvum to compare trends and relative importance of major components of bilateral morphometric variation, and their relationship with character size. Using two‐way, sides‐by‐individuals ANOVA , four components of variation were estimated for each bilateral variable: individual variation (I), directional asymmetry (DA), non‐directional asymmetry (NDA) and measurement error (E). Both species exhibit similar major trends of variation in asymmetry across characters, as shown by principal component analysis, using variance components as variables. Degree of interspecific congruence among characters was confirmed by a two‐way ANOVA with species and variance components as fixed factors. Congruence of asymmetry patterns between species suggests that the concept of population asymmetry parameter (PAP) could be extended to higher hierarchies. PAPs above the species level may result from common mechanisms or similar developmental constraints acting on species’ buffering capacities and morphological integration processes.     

Disentangling allometry and response to Kellwasser anoxic events in the Late Devonian conodont genus Ancyrodella

Is the ability to respond to minor perturbations a key to survival to major crisis? This idea was supported by previous studies on Late Devonian conodonts. Genera surviving the Frasnian/Famennian (F/F) crisis, at the end of the Upper Kellwasser anoxic event, had shown a response to a similar but minor event, the Lower Kellwasser (LKW). In contrast, the genus Ancyrodella went extinct at the F/F crisis. This study aims to assess whether this extinction was associated with the absence of response to the minor LKW event. For this purpose, the shape of the P1 platform elements of the conodont Ancyrodella curvata was quantified based on their 2‐D outlines. Conodonts were extracted from two outcrops documenting the Late Devonian Kellwasser events, Coumiac (France) and Mrirt (Morocco). Ancyrodella curvata is characterized by a marked allometric growth that may blur any other source of shape difference, like response to the LKW. Hence, a multivariate method was developed to disentangle size‐free from size‐related shape variations. No coherent temporal size variations emerged from the analysis, but allometry occurring along the growth of the element indeed appeared as the prevailing source of shape variation. By isolating size‐free variations, however, we were able to evidence a morphometric response of A. curvata to the LKW independent from the allometric pattern. Hence, the extinction of A. curvata at the F/F crisis cannot be attributed to an absence of response to minor events. The amount of shape change involved in the LKW shift is, however, of minor importance in comparison with the shape variation due to allometric growth. Alternate hypotheses have been further investigated. Ancyrodella curvata appears as a rare species in the assemblages, and its distribution worldwide suggests a rather specialist taxon. Considering survivorship curves (i.e. frequency distribution of the conodont as a function of its size) A. curvata was characterized by low and constant mortality rate. This may be a clue for a long growth and progressive investment in the reproduction. These arguments support the view that A. curvata was a rather specialist, rare and ‘K‐selected’ taxon. All these factors may not be exclusive and their unfavourable conjunction might have been the key to the extinction of A. curvata.     

Testing hypotheses of element loss and instability in the apparatus composition of complex conodonts: articulated skeletons of Hindeodus

Knowledge of the conodont skeleton, in terms of the morphology of the elements and the positions they occupy, provides the foundation for understanding of homology, taxonomy and evolutionary relationships in conodonts. This knowledge also underpins analyses of conodont functional morphology and feeding. Direct evidence of skeletal anatomy and apparatus architecture comes from natural assemblages: fossils that preserve together the articulated remains of the conodont apparatus, either collapsed onto a bedding plane or as clusters of elements in which juxtaposed and overlapping elements have been fused together by diagenetic minerals. Here we describe six clusters of the biostratigraphically important conodont Hindeodus parvus from the Lower Triassic Shangsi section, Sichuan Province, South China. Five of these clusters represent the partial remains of articulated skeletons, providing direct evidence of the number and arrangement of elements in the apparatus. Combined with data from previously published natural assemblages this provides a test of the hypothesis that Triassic conodonts had a reduced dentition. Hindeodus parvus possessed a complete raptorial array of two M and nine S elements (unpaired S₀; symmetrically paired S₁, S₂, S₃, S₄); the paired P₁ locations were occupied by carminiscaphate elements, but the apparatus lacked P₂ elements. This is consistent with broader evidence for a particularly high degree of integration and constraint operating on the S–M array of morphologically complex conodonts, leading to conserved architecture of the array over a period of more than 250 million years. The loss of elements from the P domain implies a change in food processing ability and, given the predominance of data from P elements in conodont taxonomy and biostratigraphy, the hypothesis of element loss from the P domain has significant implications for the broader understanding of conodont diversity and evolutionary patterns.     

New conodonts of the genus <Emphasis Type="Italic">Polygnathus</Emphasis> from the Evlanovian and Livnian (Upper Devonian) of the Voronezh Anteclise (central Devonian Field)

New conodont species of the genus Polygnathus (P. krutoensis sp. nov., P. makhlinae sp. nov., P. menneri sp. nov., P. obruchevae sp. nov.) are described from the Evlanovian-Livnian (Upper Devonian) deposits of the Voronezh Anteclise (central regions of the Rassian platform). The ontogenetic series of the new species are presented.     

A complete survey of normal pores on a smooth shell ostracod (Crustacea): Landmark‐based versus outline geometric morphometrics

Pores and sensilla on ostracod shell have often been used in studies of ontogeny, taxonomy, and phylogeny of the group. However, an analysis of sexual dimorphism and variation between valves in the number and distribution of pores is lacking. Also, such studies have never been done on a widely distributed, morphologically variable, and weakly ornamented freshwater ostracod. Here, we survey pores in one such species, Physocypria kraepelini . We choose 27 homologous pores as landmarks for 2D‐geometric morphometric analysis, with the aim to assess intersexual and between valves variation in size and shape relative to the Fourier outline analysis. This species has only simple (Type A) pores with and without a lip, and each pore carries an undivided sensory seta. Our results show that the total number of pores varies (from 270 to 296), but this is not associated with a specific valve. Males carry fewer pores than females, however no sex specific pores are found. Small intrapopulation divergence of the Cyt b molecular marker (1%) indicates that morphological variability is not species related. We found that P. kraepelini exhibits directional asymmetry of size and shape, sexual size dimorphism (SSD) but lacks sexual shape dimorphism (SShD). Two geometric morphometrics methods were congruent in the estimation of SSD, SShD, and directional asymmetry of shape but differ in the statistical evaluation of directional asymmetry of size. Contrary to other animal groups, our study suggests that ostracods have more pronounced directional asymmetry of shape compared to directional asymmetry of size.     

Frasnian conodonts from the eastern Russian Platform

The Frasnian conodonts of the eastern Russian Platform from the Timan in the north to the Orenburg Region in the south are characterized in detail both paleontologically and stratigraphically. This paper is a continuation of a previously published monograph (Ovnatanova and Kononova, 2001) on the Frasnian conodonts of the shallow-water strata of the central Russian Platform, where polygnathids prevail. The conodont assemblages from the shallow-water and basinal sections of the Volga-Ural province and Southern Timan are analyzed. Problems and difficulties associated with the correlation of the shallow-water and deep-water Frasnian sections of the eastern Russian Platform and their correlation with the existing zonal conodont scales are discussed. The correlation between the deep-water Mendym deposits and the shallow-water Rechitza and Voronezh strata of the Volga-Ural province with the Vetlasyan and Sirachoi deposits of the Southern Timan is substantiated. The stratotype of the Semiluki Regional Stage of the Central Devonian Field contains equivalents of the lowermost beds of the Domanik Formation (unit 1), based entirely on polygnathids. Phylogenetic reconstructions for Palmatolepis and Polygnathus are suggested based on the ontogenetic series for some species of these two genera and the presence of transitional forms between some of the species. Based on these phylogenetic reconstructions, conodont zonal scales for the shallow-water and deep-water sections of the Frasnian Stage of the Russian Platform are proposed and their correlation with the existing conodont zonal scales is also adduced. Some aspects of biofacies control are considered based on the distribution of conodonts in the sections studied. In Systematic Paleontology, 91 conodont species of the genera Ancyrodella, Mesotaxis, Palmatolepis, and Polygnathus are described, including the new species Palmatolepis menneri, P. kaledai, P. acutangularis, and Polygnathus reitlingerae. DEDICATION To the blessed memory of the outstanding geologist Vladimir Vladimirovich Menner     

Are geometric morphometric analyses replicable? Evaluating landmark measurement error and its impact on extant and fossil Microtus classification

Geometric morphometric analyses are frequently employed to quantify biological shape and shape variation. Despite the popularity of this technique, quantification of measurement error in geometric morphometric datasets and its impact on statistical results is seldom assessed in the literature. Here, we evaluate error on 2D landmark coordinate configurations of the lower first molar of five North American Microtus (vole) species. We acquired data from the same specimens several times to quantify error from four data acquisition sources: specimen presentation, imaging devices, interobserver variation, and intraobserver variation. We then evaluated the impact of those errors on linear discriminant analysis‐based classifications of the five species using recent specimens of known species affinity and fossil specimens of unknown species affinity. Results indicate that data acquisition error can be substantial, sometimes explaining >30% of the total variation among datasets. Comparisons of datasets digitized by different individuals exhibit the greatest discrepancies in landmark precision, and comparison of datasets photographed from different presentation angles yields the greatest discrepancies in species classification results. All error sources impact statistical classification to some extent. For example, no two landmark dataset replicates exhibit the same predicted group memberships of recent or fossil specimens. Our findings emphasize the need to mitigate error as much as possible during geometric morphometric data collection. Though the impact of measurement error on statistical fidelity is likely analysis‐specific, we recommend that all geometric morphometric studies standardize specimen imaging equipment, specimen presentations (if analyses are 2D), and landmark digitizers to reduce error and subsequent analytical misinterpretations.     

Sedimentary and biofacies records in calciturbidites at the Devonian-Carboniferous boundary in Moravia (Moravian-Silesian Zone, Middle Europe)

Summary At the Devonian/Carboniferous boundary, major climatic and oceanographic changes influenced sedimentation on carbonate platforms and in peri-platfrom asreas. Three deep-water carbonate successions in Moravia, which were selected to represent different paleotectonic settings, have been studied with the aim of testing the influence of eustatic, climatic and tectonic controls on sedimentation and conodont paleoecology and taphonomy. On the slopes of the wide carbonate platforms of the Moravian Karst Development (Lesní lom and Grygov sections), an exemplary highstand shedding systems developed in the upper Famennian (expansa Zone), marked by a pronounced thickness of their respective calciturbidite successions and an abundance of shallow-water skeletal grains.Palamatolepis— andBispathodus-dominated conodont assemblages contain an admixture ofPolygnathus representing a transported, near-shore component. The eustatic sea-level fall in the praesulcata Zone and the lowstand conditions at the D/C boundary resulted in a decline of carbonate platform production and condensed deposition or nondeposition. In the Lesní lom section, a condensed sequence of turrbiditic calcarenites and shales (Middle praesulcata—lowermost sulcata Zone) was followed by lime mud calciturbidites (sulcata and duplicata Zones). In the conodont assemblages, the first event in the Lower praesulcata Zone was associated with the reduction of ‘mesopelagic’Palmatopic and a bloom of epipelagicPolygnathus communis. The second event in the Middle praesulcata Zone corresponds to the onset of polygnathidprotogranthodid biofacies, indicating a carbonate slope environment. In the Grygov section, a pronounced thickening and upward-coarsening succession of tubiditic calcilutites through calcarenites and intraclast breccias, with poor palmatolepid-bispathodid connodont assemblages (expansa Zone), indicates a progradation of the calciturbidite system associated with sea-level highstand. After a break in sedimentation, covering the interval from the Lower praseulcata to the base of Lower crenulata Zone, thick-bedded, fine-grained calciturbidites were deposited in the Lower crenulata Zone, and are associated with poor, mixed assemblages where siphonodellids and polygnathids predominate. At the isosticha-Upper crenulata/Lower typicus boundary, coasre grained, turbiditic calcarenites and breccias rich in clastic quartz grains and mixed conodont assemblages with reworked Frasnian and Famennian conodonts indicate a deep erosion of the source area, presumably due totectonic uplift (relative lowstand). In the Jesenec section, on the flanks of the volcanic seamount (the Drahany Development), a deep-water Upper Famennian condensed succession of calciturbidites and presumably winnowed pelagic limestones is marked by conodont assemblages of palmatolepid-bispathodid biofacies. More proximal calciturbidites with mixed deep-water and shallowwater conodonts prograde at the top of the Upper Famennian succession (Middle to Upper expansa Zone). A striking hiatus, covering the interval from the Early preaesulcata to the base of Lower crenulata Zone, resulted from extreme condensation and submarine bottom current erosion due to sea-level lowstand in the late Famennian and early Tournaisian. The renewed middle Tournaisian calciturbidite sedimentation with strong evidence of erosion at the source area indicates global eustatic rise and tectonic uplift of the Drahany Development seamounts (relative lowstand). The earlier occurrence of the uplift in the Jesenec area, relative to the Grygov section, shows the advance of tectonic processes over time in the Moravian-Silesian basin (orogenic polarity) as a consequence of Variscan orogenic movements.     

New records of the conodont genus <Emphasis Type="Italic">Polygnathus</Emphasis> from the Lower Famennian of Mugodzhary,Western Kazakhstan

Representatives of the genus Palmatolepis, along with new species of the genus Polygnathus (Po. schinkaryovi sp. nov. and Po. bertchogurensis sp. nov.) are recorded in carbonate deposits of the Burtebayian Formation of the Lower Famennian of Mugodzhary (Western Kazakhstan). They co-occur with Polygnathus polesicus Strelchenko, which is described for the first time in the Lower Famennian of Belarus.     

Step-wise morphological trends in fluctuating environments: Evidence in the Late Devonian conodont genus Palmatolepis

Long-term morphological changes were investigated in the conodont genus Palmatolepis, using a Fourier analysis of the outline of platform elements. Three time-slices and four Late Frasnian - Early Famennian sections on North Gondwana were studied. No difference existed between locations, but shape variations were recorded associated with the successive Kellwasser events. The Middle Famennian period was analyzed in a section located at the Baltica margin across the annulata event. Some morphological changes may be related to the deposition of the corresponding black shales, but the main feature is a heterogeneity of the populations, which can be split into two morphological types. Latest Famennian conodonts from another North Gondwanan section show only minor shape changes during this time interval, which is environmentally stable prior to the global Hangenberg event. Based on synthetic shape variations across the whole period an morphological trend towards narrower elements is observed. This morphological change happens step-wise in response to global events. The amplitude of the shape shift is proportionally related to the extend of the successive Late Devonian global events.     

Environment and space as drivers of variation in skull shape in two widely distributed South‐American Tayassuidae,Pecari tajacu and Tayassu pecari (Mammalia: Cetartiodactyla)

The influence of the environment on the geographical variation of morphological traits has been recognized in a number of taxa. Pecari tajacu and Tayassu pecari are ideal models to investigate intraspecific geographic variation in skull because of their wide and heterogeneous geographical distribution in South America. We used geometric morphometric procedures to examine the geographical variation in skull shape of 294 adult specimens of these species from 134 localities. We quantified to what extent skull shape variation was explained by environment, skull size and geographical space using variation partitioning analysis. We detected a strong pattern of geographic variation for P. tajacu skull shape, but not for T. pecari. The environment seems to be the major selective force that drives skull shape variation in both species. Nevertheless, other spatially structured processes (e.g. genetic drift, gene flow) might also have affected variation in the skull shape of the more widespread species P. tajacu. Allometric relationships might reflect the biomechanical constraints that are thought to be strong enough to limit size‐related changes in T. pecari skull shape.     

GEOMETRIC MORPHOMETRICS OF DEVELOPMENTAL INSTABILITY: ANALYZING PATTERNS OF FLUCTUATING ASYMMETRY WITH PROCRUSTES METHODS

Although fluctuating asymmetry has become popular as a measure of developmental instability, few studies have examined its developmental basis. We propose an approach to investigate the role of development for morphological asymmetry by means of morphometric methods. Our approach combines geometric morphometrics with the two-way ANOVA customary for conventional analyses of fluctuating asymmetry and can discover localized features of shape variation by examining the patterns of covariance among landmarks. This approach extends the notion of form used in studies of fluctuating asymmetry from collections of distances between morphological landmarks to an explicitly geometric concept of shape characterized by the configuration of landmarks. We demonstrate this approach with a study of asymmetry in the wings of tsetse flies (Glossina palpalis gambiensis). The analysis revealed significant fluctuating and directional asymmetry for shape as well as ample shape variation among individuals and between the offspring of young and old females. The morphological landmarks differed markedly in their degree of variability but multivariate patterns of landmark covariation identified by principal component analysis were generally similar between fluctuating asymmetry (within-individual variability) and variation among individuals. Therefore there is no evidence that special developmental processes control fluctuating asymmetry. We relate some of the morphometric patterns to processes known to be involved in the development of fly wings.     

A new species of <Emphasis Type="Italic">Pelekysgnathus</Emphasis> (Conodonts) from the Famennian of the east Russian Platform

A new conodont species, Pelekysgnathus aristovi sp. nov., from the Middle Famennian shallow-water carbonate deposits of the South Tatar Dome in the eastern Russian Platform is described.     

Mandibular Shape, Ontogeny and Dental Development in Bonobos (Pan paniscus) and Chimpanzees (Pan troglodytes)

The postnatal ontogenetic patterns and processes that underlie species differences in African ape adult mandibular morphology are not well understood and there is ongoing debate about whether African ape faces and mandibles develop via divergent or parallel trajectories of shape change. Using three-dimensional (3D) morphometric data, we first tested when in postnatal development differences in mandibular shape are initially evident between sister species Pan troglodytes and P. paniscus. Next, we tested whether each species has a distinct and non-parallel trajectory of mandibular development. Mandibles sampled across a broad developmental range of wildshot bonobos (n = 44) and chimpanzees (n = 59) were radiographed and aged from their dental development. We then collected 3D landmark surface data from all the mandibles. A geometric morphometric analysis of size-corrected 3D data found that bonobos and chimpanzees had parallel and linear ontogenetic trajectories of mandibular shape change. In contrast, mandibular shape was statistically different between P. paniscus and P. troglodytes as early as infancy, suggesting that species shape differences are already established near or before birth. A linear and stable trajectory of shape change suggests that mandibular ontogeny in these apes is unimpacted by non-linear variation in tooth developmental timing.     

Upper Devonian conodonts of northeastern European Russia

The conodont succession in the Upper Devonian facially different sections of northeastern European Russia (Chernyshev Ridge, Subpolar and Polar Urals, Pai-Khoi) are studied. The sections are subdivided and correlated taking into account the global standards for stages. The Frasnian Montagne Noire zonation (Klapper, 1989) is used for the first time for northeastern European Russia; the authors correlated this zonation with the scale of Ziegler and Sandberg (1990). Famennian deposits are subdivided using scale of Ziegler and Sandberg (1984) and miospore zonation. The age of local geological units (formations) is specified; the formations of different regions of northeastern European Russia are correlated to each other and to the regional subdivisions of EEP and Southern Urals. A total of 93 species of Ancyrodella, Mesotaxis, Palmatolepis, Polygnathus, and Zieglerina are described. Two new species Ctenopolygnathus parallelus sp. nov. and Polygnathus masonae sp. nov. are distinguished and five species are described in the open nomenclature. Special chapter is devoted to the phylomorphogenesis of Ancyrodella.     

Morphological criteria for recognising homology in isolated skeletal elements: comparison of traditional and morphometric approaches in conodonts

Abstract: Accurate hypotheses of primary homology are fundamental to many aspects of the systematics and palaeobiology of fossils. They are particularly critical for conodonts: virtually all areas of conodont research are underpinned by homology, yet the majority of conodont taxa are found only as disarticulated skeletal elements, and hypotheses of element homology are inferred from morphological comparisons with complete skeletons. This can cause problems in taxa where more than one location within the conodont skeleton is occupied by elements with similar morphology. In such cases, morphological comparisons can yield equivocal or erroneous hypotheses of homology of isolated elements. The Eramosa Lagerstätte of Ontario (Silurian, Wenlock) preserves both isolated skeletal elements and articulated conodont skeletons. The latter provide a topological context within which to test hypotheses of element homology and allow blind testing of qualitative discrimination of elements. When applied to P₁ and P₂ elements of Wurmiella excavata, this revealed inaccuracy and inconsistency in distinguishing these P element types. Standardised morphometric protocols were used to further test the efficacy of those characters used in traditional qualitative identification of P element homology, revealing that, individually, none of these characters provides an effective discriminator between P element types. Principal components and discriminant function analyses of ten ‘traditional’ morphological variables combined can distinguish P₁ from P₂ elements with a similar success rate to expert identification. Eigenshape and elliptic Fourier analyses of element outlines proved less effective at capturing shape differences that allowed for discrimination between P₁ and P₂ elements. Analysis of both traditional and outline data demonstrates that in some individuals P₁ and P₂ elements are morphologically distinct from one another, while in others they are almost indistinguishable. These results demonstrate that although qualitative assessments of homology can be prone to error, especially when undertaken by inexperienced researchers, the morphometric and analytical protocols used here provide effective additional tool for discriminating morphologically similar but non‐homologous elements. These methods thus hold promise of broad application to other conodont taxa where identification of element homology in collections of isolated specimens is problematic.     

RECONSTRUCTION OF AN APPARATUS OF NEOSTRACHANOGNATHUS TAHOENSIS FROM ORITATE,JAPAN AND SPECIES OF NEOSTRACHANOGNATHUS FROM OMAN

Abstract: The apparatus of an Early Triassic conodont Neostrachanognathus tahoensis Koike, 1998 from Oritate, Kumamoto Prefecture, Japan, and a species of Neostrachanognathus from Oman were reconstructed. On the basis of five natural assemblages from the Oritate area, the three‐dimensional apparatus model of N. tahoensis is interpreted as bilaterally symmetrical and composed of 14 elements consisting of pairs of P₁, P₂, P₃, S₁, S₂, S₃, and S₄ elements. The P₁ and P₂ elements are coniform elements, the P₃ elements are digyrate forms, and the S elements are bipennate ramiforms. The S elements are arranged rostrally in the apparatus and the pairs of the P₁, P₂, and P₃ elements are subvertically arranged caudally and ventrally to the S array. One of the natural assemblages was formed by rostrocaudal collapse of the apparatus on the sea floor, whereas the other assemblages indicate that conodont animals came to rest nearly parallel with the substrate prior to burial. A collection of isolated elements from Jabal Safra, Oman, includes a second species of Neostrachanognathus with a comparable apparatus.     

Getting into Shape: An Empirical Comparison of Traditional Truss-Based Morphometric Methods with a Newer Geometric Method Applied to New World Cichlids

Body shape is a difficult, but important, trait to quantify. Researchers have traditionally used multivariate analysis of several linear measures ('trusses') across the body form to quantify shape. Newer geometric morphometric methods claim to better estimate shape because they analyze the geometry among the locations of all landmarks simultaneously rather than the linear distances between pairs of landmarks. We tested this claim by comparing the results of several traditional morphometric analyses against a newer geometric analysis involving thin-plate splines (TPS), all applied to a common data set of morphologically variable new world cichlids Amphilophus citrinellus and A. zaliosus. The TPS method yielded slightly stronger evidence of morphological differences among forms, although traditional methods also distinguished the two species. Perhaps our most important result was the idiosyncratic interpretation of shape variation among the traditional truss-based methods, whereas the generation of deformation grids using the TPS approach yielded clear and visually interpretable figures. Our results indicate that geometric morphometrics can be a more effective way to analyze and interpret body form, but also that traditional methods can be relied upon to provide statistical evidence of shape differences, although not necessarily accurate information about the nature of variation in shape.