摘要:

Re-examination of the type material, and study of new specimens of the Upper Silurian mitrateVictoriacystis wilkinsiGill & Caster from the Heathcote area of Victoria, Australia, reveal additional details of its anatomy. Mitrates from the Lower Silurian of Hawthorn and the Lower Devonian of Kinglake West (Victoria, Australia) are assigned toV. wilkinsi. New morphological features ofVictoriacystisare: a sculptured median upper lip plate; five transverse rows of ventral plates; a complex ornament on the internal surface of the anteriormost ventral plates; a flexible articulation between dorsal and ventral fore-tail plates; and the presence of knobs on the ventral hind-tail plates.Victoriacystiswas probably a semi-infaunal animal which moved rearward within the sediment pulled by its tail. Yawing was reduced by the deep lateral head walls. The fore-tail could be flexed laterally to a large extent, whereas the hind-tail could proably also act as a lever. Spines might have helped the animal to rest on sediment, to increase stability in water currents, and/or to bring food particles in suspension.

ISSN:0311-5518    

DOI:10.1080/03115519708619177

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The Early Permian amphibianArchegosaurus decheniGoldfuss, originally reported from Germany, is described, based on a collection of thirteen skulls housed in the Museum of Victoria, Melbourne, Australia. New and previously poorly known features described include: the presence of an intermaxillary foramen, pterygoid-vomer contact, well developed adductor flange of the pterygoid, very long choanae, absence of interchoanal and parachoanal tooth rows, and development of paired anterior palatal fossae. A scheme of cladistic relations between archegosauroid genera and other temnospondyl families is proposed.

ISSN:0311-5518    

DOI:10.1080/03115519708619178

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Eutreptodactylus itaboraiensisfrom Late Paleocene karst deposits of eastern Brazil is the oldest and most primitive member of the Cuculidae known to date. It is one of the oldest fossils that can be placed in a modern family of birds. The zygodactyl condition, characterising the cuculids, is present inEutreptodactylus, but the relative rotation of the trochlea metatarsi IV is slight in comparison with that in extant cuculids, suggesting that this bird may not have been an obligate zygodactyl form. Since zygodactyly had developed within the Cuculiformes by the Late Paleocene, it follows that the other family in this order, the Musophagidae, must have diverged by the early part of the Cainozoic.

ISSN:0311-5518    

DOI:10.1080/03115519708619179

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The monocotyledon macrofossilDesmiophyllumsp. α Seward & Conway is recognised as being close in its cuticular features and stomatal sculpturing to several New Zealand and Mascarene species ofCordyline. However, because the fossil cannot be placed unequivocally inCordylineit is assigned to a new form genusParacordylineasP. kerguelensiswith affinities to the extant aborescent woody monocotCordyline(Lomandraceae).

ISSN:0311-5518    

DOI:10.1080/03115519708619180

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Charophyte gyrogonites from two Miocene sites in northern Thailand are studied and compared for population variation. Morphometrical differences between the two populations, determined asNitellopsis merianiiandN. meriani globula, correspond to variation at the interpopulation level and do not justify the distinction of two separate species as made by previous authors. The first exhaustive synonymy for both taxa is listed. Morphological differences can be attributed to environmental differences as reflected by distinct lithologies of the samples concerned.

ISSN:0311-5518    

DOI:10.1080/03115519708619181

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Within the Weipa bauxite deposit of northern Queensland, Australia, are rare ovoid structures averaging 49 × 30 mm in size and of a similar composition to the surrounding bauxite. Comprised of a thin shell with an opening near one end, these structures encase ordinary bauxitic pisolitha and are referred to as ovate compound pisoliths. A small proportion of them are completely hollow and have no apparent opening into their chamber. Similar calcareous structures are found along the west coast of Eyre Peninsula, South Australia. These calcareous structures are interpreted to have been constructed by the larval stage of the weevilLeptopius duponti, for protection during pupation. The calcareous structures have a similar size and shape to bauxitic pisoliths, suggesting that ovate compound pisoliths may have been constructed by a similar organism, possibly belonging to the genusLeptopius.

ISSN:0311-5518    

DOI:10.1080/03115519708619182

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor