摘要:

Comparison of ontogenetics suggest that the Middle CambrianXystriduraevolved from the Lower Cambrian speciesHsuaspis bilobataby changes in the rate or timing of development of characters during ontogeny. Extension of the juvenile growth period delayed maturation, or hypermorphosis resulted in exaggeration of normally slow, early holaspid growth patterns within the rapid, late meraspid growth stage, producing a marked progradation of the glabella inXystridura. Forms referable toH. cerastesfrom the upper Early Cambrian Cymbric Vale Formation of New South Wales appear to show the beginnings of this hypermophic trend.

ISSN:0311-5518    

DOI:10.1080/03115519908619334

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The squamation of a complete palaeoniscoid,M. durgaringaGardiner & Bartram, 1977, from the Frasnian Gogo Formation is described. A variety of isolated scales from the Gneudna Formation, Carnarvon Basin, are referred toM. durgaringaon the basis of comparison with the described articulated specimen. Scales of various forms are attributed to specific regions of the body.

ISSN:0311-5518    

DOI:10.1080/03115519908619335

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The problematic Mississippian-Cretaceous fossilShamovella(=Tubiphytes) has been referred to the cyanobacteria, algae and invertebrates (sponges, hydrozoans, foraminifera). These conflicting interpretations of affinity are based on morphology. Hitherto there has been little emphasis on the palaeoecological and palaeogeographic distribution ofShamovella, although this could provide further information relating to its systematic position.

ISSN:0311-5518    

DOI:10.1080/03115519908619336

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Djaludjangi yadjanasp. nov. represents a previously unknown genus of petauroid possum from Riversleigh in northwestern Queensland. Of known phalangeridansDjaludjangimost closely resembles the Petauridae, but lacks synapomorphies previously used to define that family. Although considered likely a plesiomorphic petaurid,D. yadjanais referred here to Petauroidea:incertae sedis, pending comprehensive revision of phalangeriform dental character state distributions. Small possum diversity at Riversleigh indicates a complex and finely partitioned environment such as that found in present-day tropical forests; the discovery at Riversleigh of Australia's first Tertiary dactylopsiline species also argues for a rainforest palaeohabitat.

ISSN:0311-5518    

DOI:10.1080/03115519908619337

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A complete large mandible from the early Miocene Neville's Garden Site, Riversleigh, northwestern Queensland, Australia, represents a new genus and species of songbird,Longimornis robustirostrata. L. robustirostratais referred to the Oriolidae, closest to the figbirdsSphecotheres. It is the third named passerine from the Tertiary of Australia.

ISSN:0311-5518    

DOI:10.1080/03115519908619338

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The density of conodont elements is between 2.90 g cm-3and 3.04 g cm-3, probably very close to 3.00. Removing all traces of dolomite and calcium carbonate before density separation keeps the viscosity of sodium polytungstate solution low enough to make it useful for density separations as high as 3.04 g cm-3. In most cases, a nearly clean phosphatic fraction can be produced by adding this method to existing standard techniques. The oxidizing technique to remove pyrite is also discussed. In all kinds of physical concentration work consideration of the “bulk density” is very important for good results, especially regarding coniforms.

ISSN:0311-5518    

DOI:10.1080/03115519908619339

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor