Johnny A. Waters

Universal Elemental Homology in Glyptocystitoids, Hemicosmitoids, Coronoids and Blastoids: Steps Toward Echinoderm Phylogenetic Reconstruction in Derived Blastozoa

Abstract Universal elemental homology (UEH) is used to establish homology of thecal plates and elements of the ambulacral system among clades of stemmed echinoderms by placing these structures into a testable hypothesis of homology. Here UEH is used to explore hypotheses of homology in blastoids, coronoids, Lysocystites, hemicosmitoids, and glyptocystitoids. This new approach to analyze homology is particularly powerful in understanding the nature of the thecal plates of blastoids and how they relate to other taxa in a common nomenclatural lexicon. In blastoids, deltoids are interpreted as oral plates that are homologues to oral plates of glyptocystitoids and hemicosmitoids whereas side plates are interpreted to be ambulacral floor plates. Thecal plates are homologous among blastoids, coronoids and Lysocystites but these morphologies cannot be reconciled with plate circlets of glyptocystitoids and hemicosmitoids. A phylogenetic analysis of these taxa presents the origin of blastoids as sister taxon of coronoids within a testable series of homologies.

A quadrupling of Famennian pelmatozoan diversity: New Late Devonian blastoids and crinoids from northwest China

Abstract A new diverse Famennian echinoderm fauna (∼600 specimens representing 33 genera and 47 species) dominated by blastoids and cladid, small-calyx camerate, and flexible crinoids is reported from the Hongguleleng Formation, Junggar Basin, Xinjiang-Uygar Autonomous Region, China. Two stratigraphically distinct pelmatozoan faunas were collected: one from the lower member of the Hongguleleng Formation (crepida Zone to marginifera Zone) and one from the upper member of the Hongguleleng Formation (praesulcata Zone). Both faunas are distinctively “Carboniferous” in aspect. The older fauna is dominated by cladids and small-calyx camerates, whereas the younger fauna is dominated by blastoids. Discovery of these two faunas has more than doubled the number of Famennian echinoderm specimens known in the world and more than quadrupled the number of known taxa. Latest Devonian (Famennian) and earliest Carboniferous stemmed-echinoderm (pelmatozoan) faunas traditionally have been considered to be very low diversity relative to earlier Frasnian and later Early Carboniferous faunas. Furthermore, Carboniferous pelmatozoan faunas seemingly arose suddenly, with unclear ancestral ties to Devonian taxa. The Hongguleleng faunas are critical in understanding pelmatozoan biogeography and evolution in the aftermath of Devonian extinction event(s) prior to the Carboniferous echinoderm diversification, as they indicate that diversification and re-radiation of stemmed echinoderms already were well underway before the close of the Famennian. Collections from field excursions in 1993 and 1995 include seven new taxa of blastoids and nine new taxa of crinoids among the twenty-four total taxa reported. New blastoid taxa are Emuhablastus planus, Tripoblastus plicatus, Breimeriblastus pyramidalis, B. gracilis, Conoblastus invaginatus, Sinopetaloblastus grabaui, and Hyperoblastus emuhaensis. Together with collections from 1991, we have amassed 333 blastoid specimens, representing 13 genera and 15 species. Emuhablastus planus, new genus and species, is the oldest genus of the Family Codasteridae, extending the familial record back from the Viséan to the Famennian. The hyperoblastid genera, Breimeriblastus, new genus, and Conoblastus, new genus, apparently represent transitional genera between a Pentremitidea-like ancestor and a Pentremites-like descendant. These taxa imply that the fissiculate-spiraculate transition may have occurred in a mosaic fashion during the Middle to Upper Devonian. Hyperoblastus emuhaensis, new species, is the first report of the genus from rocks of Famennian age or from Asia. New crinoid taxa include Athabascocrinus orientale, Hexacrinites pinnulata, Abactinocrinus devonicus, Euonychocrinus websteri,? Parisocrinus nodosus,? P. conicus, Bridgerocrinus discus, Julieticrinus romeo, and Sostronocrinus quadribrachiatus. In addition, we propose several other taxonomic reassignments based on new collections. Uperocrinus zhaoae is reassigned to the genus Actinocrinus based on the presence of pentagonal or hexagonal primibrachials in the cup, even though the primibrachials have a pseudo-quadrate appearance. Bridgerocrinus delicatulus is reassigned to Logocrinus based on the presence of three, rather than two, primibrachials. Sostronocrinidae, new family, is erected for genera with 20 arms that otherwise might be placed in the Family Scytalocrinidae. Genera included within the Sostronocrinidae, new family, are Sostronocrinus, Hertocrinus, Tundracrinus, and Amadeusicrinus new genus. Bridgerocrinus minutus is reassigned to the genus Sostronocrinus. Pachylocrinus subpentagonalis is reassigned to Amadeusicrinus new genus. “Decadocrinus” xinjiangensis is reassigned to Grabauicrinus new genus, which is erected for decadocrinids with 10 arms, all of which branch on the second primibrachial.

Mississippian pelmatozoan community reorganization: a predation-mediated faunal change

Crinoid genera of the subclass Camerata generally dominated Late Silurian through Middle Mississippian pelmatozoan echinoderm assemblages. This dominance reached a peak during the early and middle Mississippian (Kinderhookian-Meramecian), but abruptly ended at the close of the Genevievian Stage (=lowermost Chesterian) in eastern North America. During the Genevievian Stage, crinoids of the subclass Inadunata became taxonomically more diverse but a few camerates, especially Platycrinites and Batocrinus, continued to be numerically dominant in many pelmatozoan assemblages. In eastern North America, platycrinids and batocrinids were reduced drastically near the Genevievian-Gasperian boundary. So obvious is this faunal change that, until recently, the Meramecian-Chesterian Series boundary was recognized as the last occurrence of Platycrinites penicillus. The sudden and drastic decline of numerically dominant platycrinids and batocrinids in eastern North America suggests a mass extinction, but is better interpreted as a range contraction and loss of dominance. Platycrinids, in particular, continued to be significant components of pelmatozoan assemblages in Europe and Asia long after the end of the Genevievian Stage. We infer that this reorganization of pelmatozoan assemblages in eastern North America was a product of predation, siliciclastic tolerance, and current-energy preference, with predation playing a major role. Reorganization resulted in post-Genevievian dominance by (1) cladid crinoids, (2) camerate crinoids that were cladid homeomorphs, and (3) the blastoid Pentremites. Foraminifera, conodonts, corals, brachiopods, bryozoans, and other echinoderm groups were affected little, if any, during this same time.

A camerate-rich late carboniferous (Moscovian) crinoid fauna from volcanic conglomerate, Xinjiang, People's Republic of China

A new trace fossil from the Lower Triassic of northern Italy is described. It is a sinuous resting trace of a bilaterally symmetrical worm-like animal. The anterior end is characterised by a pair of lateral projections. It most closely resembles an acorn- worm (class Enteropneusta) in morphology. As such, it is the only known resting trace of an acorn-worm from the fossil record. . Paleont., 70( ), 1996, pp. 128-131 pyright ? 1996, Th Pale ntological Society ENTEROPNEUSTS, OR acorn-worms, are deposit-feeding, ma- rine hemichordates that can be found anywhere from in- tertidal areas to deep abyssal plains (Barrington, 1965). In shal- lower environments they tend to live in U-shaped burrows, whereas in the abyssal plains they have been photographed mov- ing freely on the substrate surface (Bourne and Heezen, 1965; Gaillard, 1991). Their fossil record is extremely poor (Benton 1993). The only known example is from the Lower Jurassic of Lombardy, Italy (Arduini et al., 1981). Bulman (1970) also lists several instances where trace fossils have been assigned to enteropneust activity. The similarity no- ticed between the spiral traces photographed by Bourne and Heezen (1965) and the trace fossil Taphrhelminthopsis is one example. However, this sort of trace could be made by any organism moving efficiently over the substrate, without crossing its own track. For example, Gaillard (1991) photographed deep- sea echinoids producing an identical trail. Enteropneust burrows have also been reported from the Muschelkalk of Poland (Kaz- mie czak and Pszczolkowski, 1969) and Upper Cretaceous of Germany (Wetzel, 1972). They consist of U-shaped burrows with funnel-shaped outlets, and usually have side branches off the head shaft (Kazmierczak and Pszczolkowski, 1969). This is ve y milar to modem day acorn-worm burrows (Barrington, 1965). However, the burrows also have horizontal connecting tubes w th short, blind-ended side branches and lack evidence of fecal castings. This morphology is very similar to the burrows f modern day shrimps figured in Bromley (1990). The inter- pretati of the Muschelkalk structures as enteropneust in origin is therefore equivocal. In c ntrast, the specimen described here is identified as being 128 This content downloaded from 157.55.39.27 on Wed, 07 Sep 2016 05:17:37 UTC All use subject to http://about.jstor.org/terms

Shallow-water facies setting around the Kačák Event: a multidisciplinary approach

Abstract In the Eifel area (western Rheinisches Schiefergebirge), a shallow- to deep-subtidal sequence of mixed carbonates and siltstones around the Kačák Event Interval close to the Eifelian–Givetian stage boundary was studied. An overall transgressive trend is inferred by the microfacies evolution. The stratigraphic variations of magnetic susceptibility in carbonates and in shale intervals show an overall decreasing evolution towards the top, which fits well with the transgressive trend. In addition, carbon and oxygen isotopes, and major, trace and rare earth element (REE) analysis have been used to get a better understanding of palaeoenvironmental variations in a shallow-water realm in the late Eifelian (kockelianus and ensensis conodont biozones): for example, the δ13C excursion and Ce anomaly are interpreted to be the local representation of the beginning of the Kačák Event Interval, which is also consistent with the stratigraphy and microfacies analyses.

A re-evaluation of Famennian echinoderm diversity: implications for patterns of extinction and rebound in the Late Devonian

Abstract Critical to understanding long-term trends in diversity is a dataset that is both worldwide in scope and based on a sound taxonomic foundation. In this paper we re-evaluate the Famennian (Late Devonian) echinoderm dataset, which has changed radically in the past decade, and reinterpret patterns of Late Devonian echinoderm extinction and rebound based on these new data. Historically, Famennian (Late Devonian) and earliest Carboniferous echinoderms have been poorly known on a global basis leading to interpretations of prolonged rebound from the Devonian extinction events. Recent discoveries of abundant and diverse Famennian echinoderm faunas from northwestern China, Colorado, Australia and Iran, together with re-examination of previously known echinoderm faunas from Germany and England, have altered drastically our understanding of the patterns of extinction and rebound of Famennian and earliest Carboniferous echinoderm communities. Overall, Famennian echinoderm diversity at the generic level is nearly five times greater than reported in the 2002 Sepkoski compilation, and familial level diversity is more than seven times greater than previously thought. Despite the increases in diversity, Famennian echinoderm faunas show a reduced diversity of camerate crinoids that typify both Middle Devonian and Lower Mississippian faunas and portend the rise of cladid crinoid diversity later in the Carboniferous. Individual Famennian faunas are numerically dominated by blastoids, which also portends trends seen at various times later in the Palaeozoic. In general, we are able to recognize the following trends. Rebound from the Late Devonian extinction events in echinoderms was more rapid than previously thought, but seems to be concentrated in Asia. Palaeogeographically Famennian echinoderms can be grouped into two broad regions: one includes China, Australia and Iran, all of which bordered the Palaeotethys; the other includes regions from Laurussia (Europe and North America) and northern Africa (Morocco).

Revision of Strunian crinoids and blastoids from Germany

AbstractIn 1930W.E. Schmidt described all known crinoids from the German Early Carboniferous, including the Etroeungt beds of Germany, which are now judged to be latest Devonian (Famennian) in age. On a global basis, Famennian camerate crinoids generally show a closer relationship to succeeding Early Carboniferous faunas than they do to older Frasnian or Middle Devonian crinoids, which also is the case for the Strunian fauna. Holdovers from older Devonian faunas include, among others,Adelocrinus, a descendant of olderArthroacantha, in England and Germany, andPetaloblastus, which is one of the youngest genera of the blastoid family Hyperoblastidae. Precursors of younger Early Carboniferous groups include platycrinoids, primitive actinocrinoids, dichocrinoids, and the blastoid genusDoryblastus, which is one of the oldest members of the family Orbitremitidae. All of these groups, which became important parts of the Early Carboniferous crinoid and blastoid radiation, give Famennian crinoid faunas much more of an Early Carboniferous than a Devonian aspect. Rhipidocrinus schmidti n. sp. is erected for specimens that originally were reported from the Etroeungt asRhodocrinus uniarticulatus. We judge that there are currently four valid species assigned toRhipidocrinus: R. crenatus, R. perloricatus, R. praecursor, and our new species,R. schmidti. Hydriocrinus ratingensis Schmidt is reassigned to ?Sostronocrinus. We note thatSchmidt (1906), notJaekel (1906) as has been reported previously, is the author ofRhipidocrinus perloricatus. Owing to the poor preservation of the Etroeungt material, we regard the namePlatycrinites wunstorfiSchmidt 1930 to be a nomen nudum.KurzfassungIm Jahre 1930 beschriebW.E. Schmidt alle damals bekannten Crinoiden des frühen Karbon Deutschlands, einschliesslich der Etroeungt-Schichten, die heute aber als spätestes Devon (Famenne) angesehen werden. Als Teil unserer laufenden weltweiten Untersuchungen an spätdevonisch bis frühkarbonischen Echinodermen haben wir nun auch die Crinoiden- und Blastoidenfauna der Etroeungt-Schichten überprüft. Auf globaler Ebene, wie auch im Fall der etroeungtischen Fauna, zeigen Kammercrinoiden des Famenne eine engere Beziehung zu den nachfolgenden frühkarbonischen Faunen als zu den älteren Crinoiden des Frasniums oder des Mitteldevons. Durchläufer aus den älteren devonischen Faunen schließen unter anderemAdelocrinus, einen Abkömmling der älterenArthroacantha Englands und Deutschlands ein, sowiePetaloblastus, eine der jüngsten Gattungen der Blastoidenfamilie Hyperoblastidae. Vorläufer jüngerer frühkarbonischer Gruppen beinhalten Platycrinoiden, primitive Actinocrinoiden, Dichocrinoiden und die BlastoidengattungDoryblastus, eines der ältesten Glieder der Familie Orbitremitidae. All diese Gruppen, die sich im frühen Karbon zu wichtigen Bestandteilen der Crinoiden- und Blastoidenverbreitung entwickelten, verleihen den Crinoidenfaunen des Famenniums einen mehr frühkarbonischen als devonischen Charakter. Rhipidocrinus schmidti n. sp. bezieht sich auf Exemplare, über die ursprünglich aus dem Etroeungt berichtet wurde, wieRhodocrinus unarticulatus. Wir gehen davon aus, dass es heute vier gültige Spezies gibt, dieRhipidocrinus zugeschrieben werden:R. crenatus, R. perloricatus, R. praecursor sowie unsere neue SpeziesR. schmidti. Hydriocrinus ratingensisSchmidt wird wieder ?Sostrocrinus zugeordnet. Wir möchten anmerken, dassSchmidt (1906) und nichtJaekel (1906), wie früher berichtet, der Autor vonRhipidocrinus perloricatus ist. Aufgrund der schlechten Erhaltung des Etroeungt-Materials betrachten wir den NamenPlatycrinites wunstorfi (Schmidt, 1930) als nomen nudum.

Late Devonian echinoderms from the Hongguleleng Formation of northwestern China

Abstract The Late Devonian, Famennian, Hongguleleng Formation of northwestern China has yielded one of the most diverse echinoderm faunas known from China. New collections and re-evaluation of earlier collections results in recognition of new taxa, increases the known diversity, provides new morphological information on some of the previously reported taxa, and provides new information on the affinity of the Late Devonian echinoderms of the Hongguleleng Formation. New crinoid taxa introduced are Gnarycrinus lanei n. gen., n. sp., Anamesocrinus tieni n. sp., Histocrinus? chenae n. sp., Eumhacrinus tribrachiatus n. gen., n. sp., Sostronocrinus aberratus n. sp. and Labrocrinus granulatus n. gen., n. sp. One new species of blastoid, Hadroblastus liaoi, n. sp. is described. Previous reports listed 46 echinoderms from the Hongguleleng Formation, including 13 blastoids and 33 crinoids. An additional 11 crinoid species bring the total crinoids to 44 species assigned to 32 genera. Similarly, the one additional species of blastoid brings the totals to 14 species assigned to 12 genera. The new echinoderms described herein include the first report of a dimerocrinitid, amphoracrinid, allagacrinid, glossocrinid, histocrinid, cercidiocrinid, dactylocrinid and neoschismatid from the Devonian of northwestern China. Additional morphologic information is provided for three of the previously described taxa and a revision of species assigned to Grabauicrinus is proposed. The crinoids and blastoids suggest closer affinity with Mississippian faunas than with Devonian faunas, and with North American faunas than European faunas. Collectively the blastoid and crinoid faunas from the Hongguleleng indicate that rediversification happened rapidly after extinction in contrast to current suggestions of a long interval of lowered origination following these extinction events.

Middle mississippian blastoid extinction event.

The Middle Mississippian blastoid (Phylum Echinodermata) extinction event (about 340 million years ago) was a rapid, habitat-specific extinction. Blastoids became rare or absent in shallow-water environments after the extinction, and this change was probably synchronous worldwide. Onshore-offshore habitat shifts have been recognized as an important historical trend among marine benthos. Unlike trends exhibited by other groups, blastoids appear to have repopulated shallow-water habitats after a period of diminished diversity and abundance.

Palaeoenvironmental study of the Palaeotethys Ocean: the Givetian-Frasnian boundary of a shallow-marine environment using combined facies analysis and geochemistry (Zefreh Section/Central Iran)

The Zefreh section in central Iran represents a carbonate ramp succession with a general shallow-marine palaeoenvironment. This section represents most of the Bahram Formation (Givetian to at least Middle falsiovalis Zone) and consists of a very heterogeneous succession of medium- to coarse-grained sandstones, skeletal pack- to grainstones with local biostromes, massive or laminated dolostones, and shales. Microfacies analysis allowed the discrimination of 12 microfacies reflecting supratidal to open marine palaeoenvironments. The shallow-marine environment was investigated using facies analysis and geochemical proxies. Redox conditions in the Zefreh section appear to be primarily oxic and support the facies and sedimentological results. The provenance of the Zefreh sediments using La, Sc, Zr, and Th indicates that they are most likely derived from continental arc volcanics which is consistent with the preliminary tectonic interpretations. Conodonts and brachiopods were used for establishing the biostratigraphical framework. The lack of important zonal index taxa of the widely applied conodont standard zonation requires the application of an alternative shallow-marine conodont zonation. Based on conodont and brachiopod data, the Zefreh section covers sediments ranging from the upper Givetian to lower Frasnian.