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The first definitive fossil species of the rove beetle (Staphylinidae) subfamily Phloeocharinae is described and figured from a single individual preserved in Late Cretaceous (Turonian) amber from New Jersey. The species is representative of the extant genus Phloeocharis Mannerheim and is described as Phloeocharis agerata Chatzimanolis, Newton, and Engel, new species. The specimen was imaged using traditional light microscopy as well as synchrotron propagation phase contrast microtomography, permitting a detailed examination of otherwise difficult to observe features. Examination revealed remarkable homogeneity across many characters with those of extant relatives, highlighting considerable morphological stasis in the genus over the last 90 million years.
A comprehensive, high resolution stratigraphic database of fusulinoidean foraminifers reveals that this group of protists suffered extreme losses during the Guadalupian extinction. Most species (88%) were eliminated gradually over the course of 9 myr during the Wordian and Capitanian ages. A pulse of greatly elevated per capita extinction frequency occurred during the last million years of the Capitanian (260–259 Ma). Contrary to prevailing opinion, the end-Capitanian event did not preferentially eliminate large, morphologically complex species in the families Schwagerinidae and Neoschwagerinidae, because most species in those families were already extinct. Rather, 69 percent of the species eliminated at the end of the Capitanian were small, morphologically conservative representatives of the Ozawainellidae, Schubertellidae and Staffellidae. Survivors from these families comprised the low-diversity association of Wuchiapingian fusulinoideans. Schubertellids, and to a lesser extent ozawainellids, diversified in the late Wuchiapingian and Changhsingian ages before the final demise of fusulinoideans during the end-Permian mass extinction. The Wordian–Capitanian fusulinoidean attrition might have been caused by photosymbiont loss and habitat reduction stemming from an interval of global cooling termed the Kamura event (∼265–259.5 Ma), although the onset of fusulinoidean diversity decline predates geochemical evidence for the beginning of the Kamura event by ∼3 myr. The end-Capitanian extinction pulse might reflect environmental deterioration from the combined effects of global cooling, Emeishan effusive volcanism and sea-level lowstand.
Gap-coding permits the use of continuous metric characters in cladistic analyses. Character means are converted to integer equivalents by placing character state divisions in the locations of phenetic breaks between specimen clusters, under the assumption that these breaks represent the locations of bottlenecks in character distributions. Similarities and differences between specimens from closely related species of cystoporate bryozoans were evaluated for the first time by converting continuous morphometric measurements into gap-coded binary and multistate characters and analyzing them cladistically, rather than just phenetically, across multiple species of Strotopora, Cliotrypa ramosa and Fistulipora compressa.
Our results demonstrate that cladistic analysis of gap-coded morphological characters can be effective in resolving phylogenetic relationships at low taxonomic levels (within and among genera) while objectively highlighting both the morphological features that specimens (taxa) share and those characteristics that differentiate them. Differences in cystiphragm abundances and sizes, especially in the proximal portions of colonies, discriminate between species of Strotopora. Colony size and growth form, abundances and lengths of hemiphragms, and sizes of cystopores discriminate between Strotopora and the closely related genus Cliotrypa. Cladistic patterns indicate that Strotopora foveolata Ulrich is a valid species with Strotopora dermata as its junior subjective synonym. Fistulipora compressa is reassigned to the genus Strotopora whereas a decision on the taxonomic status of Cliotrypa ramosa requires a broader cladistic analysis of fistuliporine genera.
We present here the first report based on phylogenetic analyses of small subunit (SSU/18S) and large subunit (LSU/28S) ribosomal DNA (rDNA) sequences from a wider-than-token sample of rhynchonellide articulate brachiopods, with data from 11 of ∼20 extant genera (12 species) belonging to all four extant superfamilies. Data exploration by network and saturation analyses shows that the molecular sequence data are free from major aberrations and are suitable for phylogenetic reconstruction despite the presence of large deletions in four SSU rDNA sequences. Although molecular sequence analyses cannot directly illuminate the systematics of fossils, the independent, genealogical evidence and phylogenetic inferences about extant forms that they make possible are highly relevant to paleontological systematics because they highlight the limitations of evolutionary inference from morphology. Parsimony, distance, maximum likelihood (no clock) and Bayesian (relaxed-clock) analyses all find a tree topology that disagrees strongly with the existing superfamily classification. All tested phylogenetic reconstructions agree that the taxa analyzed fall into three clades designated A1, A2, and B that reflect two major divergence events. The relaxed-clock analysis indicates that clades A and B diverged in the Paleozoic, while clades A1 and A2 reflect Permo-Triassic (and later) events. Morphological homoplasy and possible gene co-option are suggested as the main sources for the discord between the morpho-classification, the results of cladistic analyses of morphology, and the relationships reconstructed from molecular sequences. The origin, function and evolutionary implications of the deletion-bearing rhynchonellide SSU rDNA sequences are briefly discussed in relation to pseudogenes and concerted evolution in the rDNA genomic region.
The Early Permian (Asselian) Euramerican plant Padgettia readi Mamay is reassigned to Odontopteris Brongniart, as O. readi (Mamay) Stull et al. n. comb. Distinctive elongate structures on neuropteroid pinnules of this plant, previously interpreted as fructifications, are herein reinterpreted as foliar histoid galls, structurally analogous to blister or vein galls, and probably induced by an early lineage of hemipterans or mites. These distinctive features are assigned to the new gall ichnogenus Ovofoligallites Labandeira, n. ichnogen. n. ichnosp, as O. padgetti Labandeira. The Early Permian association between an Odontopteris host and Ovofoligallites gallers probably originated during the Middle Pennsylvanian as a similar, antecedent association between Macroneuropteris scheuchzeri (Hoffmann) Cleal, Shute, and Zodrow and the maker of U-shaped surface features long known as a distinctive, unattributed damage type, but now recognizable as a likely gall. The persistence of this association between the galler and certain medullosan pteridosperms into the Permian adds to the morphological richness of the Permian galler insect fauna. The Permian ecological expansion of galling insects resulted in colonization of new host plants, primarily through a shift from the consumption of entire, mostly pteridophyte axial organs during the Pennsylvanian to the partitioning of seed plant tissues in leaves and small branches in the Permian. The Ovofoligallites galler was part of a diverse Permian galler guild involving a variety of plant taxa, organs and tissues that overwhelmingly targeted multiple lineages of seed plants.
The brachiopod genus Dicoelosia is generally considered a typical deep-water taxon. New data suggest that some species of the genus may have invaded relatively shallow-water habitats during its geological history. However, there is scant evidence for its invasion of shallow-water environments after the terminal Ordovician mass extinction. Dicoelosia occurs in the shallower-water benthic shelly assemblages of the lower Niuchang Formation (upper Rhuddanian, Llandovery) of Meitan County, northern Guizhou Province, South China. Evidence of a move to shallow water includes its morphology and population structure, regional paleogeography, sedimentology, together with the abundance and diversity of its shallow-water associates. Following the biotic crisis, deep-water environments were barely habitable, and may have driven Dicoelosia into shallower-water niches. The taxon endured the less suitable shallow-water environments until the deep-water benthic zones ameliorated after the recovery, implying a shallow-water refugium existed after the biotic crisis. A new species Dicoelosia cathaysiensis is erected herein. There is only one record of this genus in South China and this unique occurrence may reflect the distinctive paleobiogeography and environments of this region.
Bivalves have pursued an infaunal lifestyle since early in their history. Trace fossils that have been attributed to the infaunal activity of bivalves include Hillichnus, Lockeia (=Pelecypodichnus), Lophoctenium, Protovirgularia, Ptychoplasma, Siphonichnus and Scalichnus. Re-evaluation of the ichnogenera Siphonichnus and Scalichnus supports consolidation into a single ichnogenus, Siphonichnus, which has taxonomic precedence.
Siphonichnus, as redefined herein, presently includes four ichnospecies. Siphonichnus eccaensis Stanistreet et al. is an unlined vertical tube characterized by concave downward laminae penetrated by a single central shaft and is interpreted to reflect downward burrowing in response to net erosion during the life span of the animal. Siphonichnus phiale (Hanken et al., 2001) is characterized by concave upwards laminae and reflects equilibrichnial behavior by the tracemaker. Siphonichnus lepusaures n. isp. is characterized by concave upwards laminae with a pair of vertically oriented, unlined tubes at the top and is interpreted as the dwelling trace of a bivalve with paired siphons responding to sediment aggradation. Siphonichnus sursumdeorsum n. isp. is characterized by concave upwards laminae in its basal third and convex upwards laminae in its upper third and is interpreted as the dwelling trace of a bivalve exhibiting equilibrichnial behavior in a dynamic depositional setting. Consolidation of these ichnotaxa into a single ichnogenus simplifies the ichnotaxonomy and provides a means of assessing the sedimentological significance of bivalve-generated dwelling/equilibrium/escape structures.
A new basal basilosaurid cetacean, Basilotritus uheni n. gen. n. sp., comes from the late middle Eocene (Bartonian) of Ukraine. It is the earliest dated record of a cetacean from Eastern Europe. The tympanic bulla of Basilotritus uheni shares basilosaurid synapomorphies but possesses unusual traits inherited from protocetids. Cetaceans related to Basilotritus uheni and referred to as Eocetus or “Eocetus” have been recorded from Africa, Europe, North America and South America. “Eocetus” wardii from North America is recombined as Basilotritus wardii. Platyosphys paulsonii and Platyosphys einori from Ukraine are considered as nomina dubia; specimens prior referred to as Platyosphys sp. are similar or related to Basilotritus. Other records of the Eocene cetaceans from Ukraine and south Russia are identified as Basilotritus or related genera. Early basilosaurids are demonstrated to be a paraphyletic, morphologically and geographically diverse group of the genera that colonized the world ocean as late as in Bartonian age and were probably the ancestors of Neoceti, as well as of more derived basilosaurids.
Two new species of ostracods, Conchoprimitia cassidula n. sp. and Sorornanopsis avalonensis n. gen. n. sp., represent the first described Middle Ordovician ostracods from western Avalonia. They were recovered as phosphatized carapaces dissolved out of a late early Darriwilian (ca. 467 Ma) limestone boulder from the Triassic Lepreau Formation of New Brunswick, Canada. The ostracods form a low-diversity component of a higher energy, near-shore, shelf marine fauna dominated by the trilobites Neseuretus and Stapleyella and by the conodonts Drepanoistodus and Baltoniodus. The low diversity of this Avalonian ostracod fauna contrasts with more diverse (tens of species), coeval ostracod faunas from Laurentia and Baltica. The association of Darriwilian ostracods and trilobites from New Brunswick demonstrates continuing exchange of open marine, cool water biota between Avalonia, Baltica, and West and North Gondwana that began in the late early Cambrian.
Brachiopods belonging to Ambocoelia occur ubiquitously in Middle and Upper Devonian strata of the northern Appalachian Basin. Originating during the Eifelian, Ambocoelia umbonata persisted through numerous biocrises, but went extinct during the late Frasnian Kellwasser Crisis. Ambocoelia umbonata var. gregaria, the only other form of this genus that is present within the New York Devonian succession, originated around the time of the Kellwasser Crisis and persisted locally into at least the latest Famennian. Examination of syntypic material of A. umbonata var. gregaria has resulted in the taxonomic revision of this form and elevation to Ambocoelia gregaria. Comparison of ontogenetic stages and environmental preferences of A. umbonata and A. gregaria suggests that the latter exhibits a paedomorphic morphology that may have evolved from A. umbonata through neoteny. Furthermore, these comparisons also give new autecological insights for Ambocoelia, suggesting that A. umbonata was capable of living in a diversity of environments by using a variety of life positions, whereas A. gregaria was likely more specialized. This taxonomic revision provides the necessary framework for revising the biostratigraphic range of Ambocoelia and, furthermore, the evolutionary history of this genus in relation to the Lower Kellwasser Event.
Additional specimens of the problematical rodent PipestoneomysDonahoe, 1956, have allowed for recognition of a new family, Pipestoneomyidae. A new genus and species of pipestoneomyid is recognized from the late middle Eocene (Duchesnean North American Land Mammal Age; Bartonian), Argorheomys septendrionalis, which is morphologically more primitive than Pipestoneomys and demonstrates that this new family has been distinct since the Duchesnean. The Pipestoneomyidae share a number of derived characters with the Geomorpha, especially the two-part inner layer of incisor enamel of the Eoymidae. The Pipestoneomyidae differ from the Eomyidae in lacking the basic “omega” pattern of the cheek teeth of the former, so are in the Eomyoidea as a distinct family.
The following stringocephalid brachiopods are formally described from upper Givetian (late Middle Devonian) strata of the Selennyakh Range (Northeast Asia): Omolonia antiqua Alekseeva (in Alekseeva and Nuzhdina, 1967) (subfamily Omoloninae), Geranocephalus inopinusCrickmay, 1954 and Geranocephaloides krivensis n. gen. n. sp. (subfamily Geranocephalinae), Newberria gigantea n. sp., and Rensselandioidea talyndzhaensis n. sp. (subfamily Rensselandinae). Broad paleobiogeographical connections between the seas of Northeast Asia, northwest Alaska, western Canada (Manitoba), Nevada, and also between the seas of Northeast Asia and South China are clearly established in the Givetian. In addition, two new stringocephalid-bearing communities are established: 1) the Omolonia Community in early Givetian strata of the Baird Group, northwestern Brooks Range, Alaska; and 2) the Omolonia-Geranocephaloides-Newberria-Rensselandioidea Community in late Givetian strata of the Lower Prianikskay Subsuite in the Selennyakh Range, Northeast Asia, Russia. Both of these communities occur in shallow, quiet-water, lagoonal carbonate platform environments.
The Nunn Member (early Osagean) of the Lake Valley Formation of New Mexico is known for its abundance and diversity of crinoids. Although crinoids were first reported in the late 1800s, no comprehensive study of the crinoids has been conducted and a complete list of the crinoid taxa does not exist. All subclasses of crinoids occur in the Lake Valley, but the camerates are by far the dominant group. Study of the Macurda collection from the University of Michigan, the Laudon collection from the University of New Mexico, and new collections provided more than 7000 specimens, 4,500 of which were identifiable camerates. Sixty-one species of camerates are recognized in the Nunn Member, including five new species: Blairocrinus macurdai, Iotacrinus novamexicanus, Agaricocrinus alamogordoensis, Uperocrinus kuesi, and Collicrinus laudoni. This camerate fauna is very similar to that of the lower Burlington Limestone of the Mississippi Valley. An update of the crinoid taxa in the Lake Valley Formation allows for a better understanding of the temporal and geographic relationships of crinoid faunas across North American during the Early Mississippian when camerates were at their global diversity maximum. The majority of the camerates come from the western New Mexico outcrops where the Nunn Member is thicker and the marine shelf was shallower, but several also occur in association with the deep-water Waulsortian mounds.
A thalattosaur taxon, Concavispina biseridens, was recently named and briefly described. It is described here in detail and compared with other thalattosaurs, especially Xinpusaurus. Concavispina is characterized by a long skull, measuring approximately half the length of presacral portion of the vertebral column, two rows of blunt teeth on the anterior part of the maxilla, and neural spines that have convex anterior or posterior margins and V-shaped notches in their dorsal margins. Concavispina differs from all thalattosaurs except Xinpusaurus in that the anterior end of the maxilla is curved dorsally, less than five cervical vertebrae are present, and the proximal end of the humerus is wider than the distal end. Phylogenetic analysis of 40 characters suggests that Miodentosaurus occupies a basal position within Askeptosauridea, Paralonectes is the basalmost member of Thalattosauridea, Concavispina may form a clade with Xinpusaurus, and Chinese thalattosaurs do not have a close relationship with eastern Pacific forms as suggested by previous studies. Concavispina may have been similar to Xinpusaurus in overall locomotor style, but probably had a poorer swimming ability. Concavispina likely differed from Xinpusaurus in diet, for example by depending on softer food.