Klaus J. Müller

Pentastomid parasites from the Lower Palaeozoic of Sweden

Small phosphatised fossils from late Cambrian limestones of Vastergotland, Sweden, share major external features with larval extant Pentastomida, such as a prominent head with two pairs of stumpy limbs adapted for attachment, and a slender trunk of four portions. Even such details, as paired forehead structures, pores on the inner edges of the head limbs and paired papillae at the rear of the trunk correspond with structures of extant pentastomid larvae. Neither the fossils nor the Recent pentastomids add any additional body segments during growth (segment constancy). Since characters of this kind and in this combination do not occur elsewhere, the fossils are recognised as true Pentastomida. Major differences, such as distinctly divided head limbs, partial occurrence of vestigial trunk limbs, and a different mode of trunk development during growth can be explained as representing merely the plesiomorphic state of characters of Pentastomida, indicating that the fossils are representatives of its stem-group prior to branching into the two Recent lineages. The fossils clearly document the marine origin of the Pentastomida, and that their specific morphology and parasitic life style were already established in the late Cambrian at a high degree of diversification, long before the terrestrialisation of their present final hosts, the tetrapods. General arthropod affinities are recognisable not least in the nature of the limbs, but the morphology of stem- and crown-group pentastomids gives no clues for closer relationship with any of the major (eu)arthropod taxa.

Martinssonia elongata gen. et sp.n., a crustacean-like euarthropod from the Upper Cambrian 'Orsten' of Sweden

A tiny arthropod, with five growth stages, is described. Three of the instars are metanauplius‐like larvae, having unsegmented bodies and four pairs of appendages. The largest stage, with a length of about 1.5 mm, may still be immature. Its body is divided into three tagmata. The cephalon, including five appendiculate segments, h a projecting forehead with a rostral spine and a small shield with a joint between fourth and fifth segments. Eyes are absent. The trunk is composed of seven annular segments, the anterior two with appendages. The caudal end is a long pleotelson‐like segment with the anus on its ventral surface. There are seven pairs of appendages: uniramous antennulae, composed of few tubular podomeres; four pairs of biramous postantennular, almost homeomorphic cephalic appendages; two pairs on the trunk, the anterior pair being similar to the cephalic appendages except for the exopodite, the posterior being much smaller, uniramous and apparently rudimentary. Martinssonia was probably benthic, feeding on detritic particles which it stirred up from the bottom. Besides various crustacean‐like features, the new form reveals structures different from Crustacea as well as from all other known arthropodan groups. Martinssonia presumably is a descendant of an euarthropodan group, originating from the crustacean branch long before reaching the eucrustacean level of evolution.

The Stem Crustacean Oelandocaris oelandica Re-Visited

The arthropod Oelandocaris oelandica from the upper Middle Cambrian “Orsten” of Sweden was recently recognized as a member of the early phase of crustacean evolution based on additional morphological detail from new specimens. Here we present a detailed investigation of all available material. It includes the description of a 400 µm long specimen probably representing an early developmental stage. Variation in size correlated with variation of trunk-segment numbers allowed recognition of different instars. The largest specimens do not exceed an estimated length of about 1 mm, indicating that our material may consist only of immature specimens. The characteristic, extremely long antennula of O. oelandica branches into three long rods. It may have served as the major structure to sweep in food, aided by the two subsequent appendages. These and the more posterior limbs were also responsible for locomotion. Minute pores on the outer edges of the posterior limbs and on the trunk tergites possibly contained sensilla originally, which may have served as water-current detectors. The presence of a minute proximal endite only on the third head appendage suggests a rather basal position of this species within Crustacea, because comparable developmental stages of other known stem crustaceans have such an endite on more of their appendages. Reconstruction of O. oelandica and its life attitudes (referred to the largest instar known) benefited from the application of 3D modelling. These helped, e.g., in identifying the combination of the plesiomorphic feeding function of the antennulae and the specialisation of the exopods of the next two appendages as a step toward the development of a sweep-net mode of feeding, one of the key novelties in the evolution of Crustacea. Such a mode of feeding coupled with locomotion of the three anterior appendages is still practiced in the naupliar and metanaupliar phases of many extant eucrustaceans, and even some adults.

Weitere Funde von Conodonten-Gruppen aus dem oberen Karbon des Sauerlandes

ZusammenfassungEs liegen mehr als 50 Gruppenfunde von Conodonten vor, von denen 7 nach Feinpräparation im einzelnen untersucht worden sind. Die Apparate mitGnathodus integerSchmidt 1934 undGnathodus bilineatus (Roundy 1926) gleichen sich im allgemeinen Bau, und nur in den Einzelelementen weichen sie voneinander ab. Statistische Erfassung der Einbettungslagen führte zu dem Schluß, daß der Tierkörper weder ventral noch lateral ausgesprochen abgeplattet war. Die Anordnung der Elemente in den Apparaten zeigt, daß die seitherige bei den Einzelelementen vorgenommene Orientierung mit der Neigung der Zähnchen nach „hinten” nicht in jedem Falle der natürlichen Lage im Körper entsprach. Die Zähnchen sind bei den verschiedenen Elementen gegeneinander gerichtet. Von Gruppen mitTripodellus- undMetalonchodina-Elementen lagen einige Exemplare und von einer Gruppe (?) mit Idiognathodontidae g. et sp. indet. und großenLigonodina-Elementen nur ein Einzelfund vor.In der Diskussion der systematischen Stellung der Conodonten stehen die gegensätzlichen Auffassungen beider Autoren nebeneinander.H. Schmidt vertritt die Fischtheorie,K. J. Müller stellte Gesichtspunkte zusammen, die gegen die Einordnung in einen bisher bekannten Stamm des Tierreiches sprechen.

Zur systematischen Einteilung der Conodontophorida

ZusammenfassungDie verschiedenen Angaben über ein supragenerisches System der Conodonten werden zusammenfassend dargestellt und verglichen. Gegen die Fassung vonHass 1959, die auf einem einzelnen, groben Merkmal aufgebaut und rein künstlich ist, werden Bedenken geltend gemacht. Ein natürliches System kann gegenwärtig noch nicht erschlossen werden, jedoch wird die Evidenz für die Beziehungen zwischen verwandten Formen zusammengestellt und für die 26 Gattungen der Polygnathacea ein Stammbaum entworfen, der den morphologischen Übergängen zwischen den verschiedenen Formen Rechnung trägt. Die GattungenLatericriodus [*Icriodus latericrescens] undGladigondolella [*Polygnathus tethydis] sowie die UntergattungBispathodus [*Spathognathodus spinulicostatus] werden neu aufgestellt.

Milaculum n. g., ein phosphatisches Mikrofossil aus dem Altpaläozoikum

ZusammenfassungAus dem oberen Kambrium und Ordovizium von Europa, Asien und Nord-Amerika wird ein aus Phosphat aufgebautes Mikrofossil beschrieben und die stratigraphische Position des Vorkommens festgelegt. Der GattungMilaculum werden 4 Arten (Typusart:M. ruttneri n. sp.; fernerM. perforatum n. sp.;M. scandicum n. sp. undM. ethinclarki n. sp.) zugeordnet, die mit anderen phosphatischen Mikrofossilien des Altpalaozoikums verglichen werden.SummaryUpper Cambrian and Ordovician strata in Europe, Asia and North America yielded enigmatic fossils, which are described under the generic nameMilaculum (type species:M. ruttneri n. sp.; in additionM. perforatum n. sp.;M. scandicum n. sp. andM. ethinclarki n. sp.). They are compared with other problematic and phosphatic microfossils from the early Paleozoics and may be of value as guide fossils in the future.

Entöken und Bohrspuren bei den Conodontophorida

ZusammenfassungWohn- und Bohrgänge sind bei Conodonten nicht selten und wurden in einer unerwarteten Formenfülle angetrofen, die offensichtlich auf verschiedene Entstehung zurückzuführen ist. Auskolkungen der Oberfläche können primär, z. B. im Darm eines Conodonten-Fressers, oder auch durch Anätzung bei der Präparation entstanden sein.Den Basiskörper durchziehende Kanälchen wurden während des Lebens des Conodonten-Tieres durch wurmförmige Gasttiere angelegt, in manchen Fällen wurden sie wieder durch Ablagerungen des Conodontophoriden zugesetzt. Anbohrungen sind entweder auf Entöken oder auf Aasfresser zurückzuführen, wobei hauptsächlich Thallophyten, wahrscheinlich Pilze, und vielleicht auch Nematoden und Anneliden eine Rolle gespielt haben. Pyriteinschlüsse innerhalb der Anwachslamellen werden als postmortal-frühdiagenetisch unter Mitwirkung von Schwefelbakterien entstanden angesehen. Außerdem tritt posthumer Bewuchs (Epökie), z. B. durch Foraminiferen der GattungMinammodytes, auf.SummaryDomicile burrows and bored galleries are common in condonts and have been found in a unexpected variety of forms. Obviously they have originated from various biotic units. Pitting on the surface may be caused by digestion by conodonteating animal but also secondarily through the preparation by etching.Tubes in the basal plate have been formed by worm shaped guests while the conodont animal was still alive. In some cases these channels have been closed again by the conodont bearing animal. Galleries are caused either by epibionts or by organisms feeding on the dead animals, mainly Thallophyta, probably fungi, and perhaps also Nematoda or Annelida. Inclusions of pyrite within the growth lamellae most probably are caused by sulfur bacteria. Foraminifera e. g. the genusMinammodytes did grow on the isolated conodonts.

Cambrogeorginidae fam. nov., soft-integumented Problematica from the Middle Cambrian of Australia

Phosphorites from the Middle Cambrian Monastery Creek Phosphorite Member, Queensland, Australia, yielded a group of soft-bodied, microscopic fossils of yet unknown affinity. They are three-dimensionally preserved and composed of two structurally different units. In particular one of the described genera has an upper surface pattern that is strikingly similar to the Late Precambrian Dickinsonia; even the quilted pneu structure observed on Vendozoa might be present on the Middle Cambrian material. Alternatively, a possible relationship to sclerites that also consist of two structurally different units is discussed. Three new species of three new genera are described.

»heraultia« varensalensis Cobbold (crustacea) aus dem unteren kambrium, der älteste fall voti geschlechtsdimorphismus

ZusammenfassungHeraultiaCobbold, 1935 (non! Villeneuve, 1920) fällt mit großer Wahrscheinlichkeit in die Synonymie vonWatsonella Grabau, 1900. Es handelt sich um einen sehr ursprünglichen Crustaceen, der mit frühen Mollusken, den Phyllocariden und den Branchiopoden verglichen und mit Vorbehalt zu den Ostracoden (Bradorina) gestellt wird. Reiches Material aus dem Departement Hérault, Languedoc, Frankreich, ermöglichte eine ausführliche Neubearbeitung, wobei allein aus einer Fundschicht über 800 Exemplare für die statistische Untersuchung der Ontogenie zur Verfügung standen. Die Häufigkeit nimmt mit zunehmender Größe kontinuierlich ab. Es sind keine definitiven Häutungsstadien wie z. B. bei den späteren Ostracoden vorhanden. Während die teknomorphen Stadien isomorph gewachsen sind, tritt bei den gräßten Exemplaren eine Gabelung in der Verteilungskurve im Längen: Höhen-Verhältnis auf, die als durch einen Geschlechtsdimorphismus verursacht interpretiert wird.Nur 1,6 Prozent des vorliegenden Materials hat die Reife erreicht. Bei ihnen entspricht die Häufigkeitsverteilung zwischen den kurzen und gedrungenen Formen, welche als Weibchen gedeutet werden, und den längeren und schmaleren, als Männchen gedeuteten Exemplaren dem Verhältnis 4:1. Bei der überwiegenden Mehrzahl der vorliegenden Carapaces handelt es sich entweder um vorzeitig abgestorbene Tiere oder um Häutungsstadien.SummaryHeraultia Cobbold, 1935 (non! Villeneuve, 1920) most probably is a junior synonym ofWatsonella Grabau, 1900. It is a primitive crustacean, which is compared with early molluscs, Phyllocarida, Branchiopoda and Ostracoda (Bradorina) to which it is grouped with some reservations. A new description is based upon abundant material from Department Hérault, Languedoc, France. More than 800 specimens from a single bed have been utilized to plot the ontogeny. The number of specimens decreases continually with growth. The species has no defined moult stages like those observed in later ostracods. Although tecnomorph specimens grow isometrically a separation into two maxima can be observed in the latest stages. These are interpreted as due to sexual dimorphism.Only 1,6 per cent of the material are mature carapaces, the others representing either moults or individuals which prematurely died off. Of the mature specimens the more common ones are shorter and stoutly build. These are interpreted as females, whereas the more elongated and slender ones are identified as males. In the investigated sample the female to male ratio is 4:1.

Weichteile von Fossilien aus dem Erdaltertum

Phosphatisation of small, soft-bodied fossils in the Upper Cambrian of Sweden yielded rich faunal assemblages, mainly of arthropods, which have been isolated from the rock by etching techniques. The highly diverse fossils are uncompressed and constitute the best preserved material known from the Paleozoic era, exposing minute details such as fine bristles, pores of glands, and eyes. Agnostus clearly has biramous appendages and therefore, cannot be regarded as trilobite anymore. The Crustacea are the most widespread components of the phosphatised fauna. The representatives of a separate order of Ostracoda already have been studied in some detail. Other primordial crustaceans include nauplius stages and show a surprising diversity in specialisation. A similar occurrence in Upper Devonian from the Carnic Alps demonstrates that this mode of preservation is not restricted to a single environment, but also can be expected elsewhere.