Saturday, July 29, 2006

New fossil spiders

In the latest issue of the journal Palaeontology some beautifully preserved fossil spiders are described:

Cretadiplura ceara - Carapace length = 4.95mm

Dinodiplura ambulacra - Carapace length = 12.80mm

They come from the lower Creataceous Crato member of the Santana Formation In Brazil that contains many other amazingly well preserved fossils.

This reminded me that I had found the website of Paul Selden where he has kindly made available many of his publications on fossil spiders available:


Palaeontology Volume 49 Page 817 - July 2006

Abstract: The first mygalomorph spiders from the Lower Cretaceous Crato Lagerstätte of Cearà Province, north-east Brazil, are described, from adult males and females, in two new genera and species: Cretadiplura ceara Selden, gen. et sp. nov. and Dinodiplura ambulacra Selden, gen. et sp. nov. They belong to the extant family Dipluridae, hitherto known as fossils only from Tertiary strata; thus this occurrence extends the family record by some 90 myr.

See also: Santana Formation Fossils and my post: oldest orb weaving spider discovered

Friday, July 14, 2006

Moths in decline

Or rather moths join the club of declining species. I have mentioned butterflies and beetles before and now there is long term data on moths. I found this article in the Guardian:

Moths' decline may herald crisis in UK biodiversity

"Conservationists are warning of an impending crisis in British biodiversity after recording dramatic countrywide declines in some of the most common moth species. Records spanning nearly four decades show two-thirds of the country's most popular moths are declining, amounting to about 220 separate species. Numbers of 71 species, more than a fifth of the total, have plummeted by a third in the past decade.

Ecologists at the government's agricultural institute, Rothamsted Research, in Hertfordshire, said the figures added to an already gloomy picture of British biodiversity, which has seen sharp declines in bumble bees and butterflies. Fears have now taken hold that the seemingly relentless loss of insects will have a knock-on effect on birdlife.

Researchers used a network of 95 light traps, most of which have been in place since 1968, to study populations of insects drawn to the glow of the traps' lamps.

The records show that some species, including the dusk thorn and hedge rustic, have declined by more than 90% in the past 35 years.A graph showing the decline in British moths (33%). This is an average, there was no significant change in the 'north' but a greater decline in the 'south' (44%) from (1).

"The thought that these species are declining so severely is shocking. You have to remember these are, or were, common species - they're not considered rare," said Kelvin Conrad, a population ecologist who led the study, which is due to appear in the journal Biological Conservation.

The researchers divided Britain into three sections by first drawing a horizontal line across the country at the level of the Humber river. They then split the southern regions with a line running down from the Pennines.

The scientists discovered that moths local to the south-east fared worst, suffering the most species declines.

In the north, far fewer species were threatened, but the populations of those that were fell spectacularly. The south-west, including Wales, Cornwall and Devon, had the most stable populations of moths.

Dr Conrad blames a general and widespread degradation of the moths' natural habitat for the bulk of the losses, but added that climate change, light pollution and farming practices had all taken their toll.

Studies of the garden tiger moth found that climate change, in the guise of warmer, wetter winters, had gradually forced the moths to retreat from the south-east to cooler territories.

Light pollution, a term used to describe night-time lighting from office blocks and roadside lamps, is thought to disrupt moths' behaviour, either by attracting them or by fooling them into thinking it is daytime.

The findings add to recent reports that nearly three-quarters of butterfly populations in Britain have crashed as their habitats have become damaged and fragmented.

"We have now got good data on moths and butterflies, and we know bumble bees are in trouble. All the studies now point to the same thing, that we are losing many of our insect species in Britain," said Dr Conrad.

Ecologists fear that if the decline in insects is widespread, bird populations will be next to be hit. In the past 100 years, three breeding bird species have disappeared from Britain, the Kentish plover, wryneck, and red-backed shrike.

A recent study from Stanford University concluded that some 10% of the world's bird population will have become extinct by the end of the century, with a further 15% close to the brink."


1) Rapid declines of common, widespread British moths provide evidence of an insect biodiversity crisis
Kelvin F. Conrad, Martin S. Warren, Richard Fox, Mark S. Parsons and Ian P. Woiwod
Biological Conservation
Volume 132, Issue 3 , October 2006, Pages 279-291

The State of Britain's Moths

Large-Scale Temporal Changes in Spatial Pattern During Declines of Abundance and Occupancy in a Common Moth
Kelvin F. Conrad Contact Information, Joe N. Perry, Ian P. Woiwod and Colin J. Alexander
Journal of Insect Conservation, Volume 10, Number 1, March 2006

Update: bootstrap-analysis has a post on extictions that mentions the moth study: 'sunday times: extinction, coming soon to a planet near you'

Thursday, July 13, 2006

Odontogriphus omalus and Kimberella

In my previous post on Odontogriphus omalus I mentioned that Kimberella is considered to be it's early molluscan relative. Since I have found a nice picture of feeding traces called Radulichnus probably produced by Kimberella that indicate that it had a radula and rasped away at microbial mats during the Ediacaran:

The Ichnofossil Radulichnus

This links Kimberella very clearly to Odontogriphus and to later molluscs.


Trace fossils in the Ediacaran–Cambrian transition: Behavioral diversification, ecological turnover and environmental shift
Adolf Seilachera, Luis A. Buatoisb, and M. Gabriela Mángano
Palaeogeography, Palaeoclimatology, Palaeoecology Volume 227, Issue 4 , 10 November 2005, Pages 323-356

Odontogriphus omalus and the Ediacarans

In this week’s nature there is a report on the Cambrian fossil Odontogriphus omalus (1). P.Z. has a nice write up at Pharyngula but I want to discuss the relationship between Odontogriphus and earlier Ediacaran fossils. It is mentioned in the article that Kimberella may be an ancestor of Odontogriphus but it seems that many of the bilaterian fossils of the Ediacaran have greater similarities particularly Dickinsonia type organisms (2). If that is the case Spriggina, Yorgia and Chondroplon may also have similarities to Odontogriphus although they are probabaly more distant relative than Dickinsonia. It certainly seems that many of the aspects of Odontogriphus morphology can illuminte the similarly squidgy Ediacarans. Anyway here are some pics for comparison:
Odontogriphus omalus from the supplementary material to (1)

Reconstruction of an unnamed dickinsoniid from (2)

The fossil on which the above reconstruction was based. Also from (2)

Following the research on Stromatoveris and Parvancorina it seems that the Ediacarans are finally finding their place on the evolutionary tree.


1) A soft-bodied mollusc with radula from the Middle Cambrian Burgess Shale p159
Jean-Bernard Caron, Amélie Scheltema, Christoffer Schander and David Rudkin
Nature 442, 159-163 (13 July 2006) doi:10.1038/nature04894

2) Anatomical Information Content in the Ediacaran Fossils and Their Possible Zoological Affinities
Integrative and Comparative Biology 2003 43(1):114-126; (free full text)
Jerzy Dzik

Wednesday, July 12, 2006

Sleep and weight update

I have written about a lack of sleep contributing to obesity before and the possible causes of this problem. So i was interested to see this press release from eurekalert:

Sleep deprivation doubles risks of obesity in both children and adults

Sleep deprivation could be factor in obesity

Research by Warwick Medical School at the University of Warwick has found that sleep deprivation is associated with an almost a two-fold increased risk of being obese for both children and adults.

Early results of a study by Professor Francesco Cappuccio of the University of Warwick's Warwick Medical School were presented to the International AC21 Research Festival hosted this month by the University of Warwick.

The research reviewed current evidence in over 28,000 children and 15,000 adults. For both groups Professor Cappuccio found that shorter sleep duration is associated with almost a two-fold increased risk of being obese.

The research also suggests that those who sleep less have a greater increase in body mass index and waist circumference over time and a greater chance of becoming obese over time.

Professor Cappuccio says:

"The 'epidemic' of obesity is paralleled by a 'silent epidemic' of reduced sleep duration with short sleep duration linked to increased risk of obesity both in adults and in children.These trends are detectable in adults as well as in children as young as 5 years."

Professor Cappuccio points out that short sleep duration may lead to obesity through an increase of appetite via hormonal changes caused by the sleep deprivation. Lack of sleep produces Ghrelin which, among other effects, stimulates appetite and creates less leptin which, among other effects, suppresses appetite. However he says more research is needed to understand the mechanisms by which short sleep is linked to chronic conditions of affluent societies, such as obesity, diabetes and hypertension.

Francesco Branca, the Regional Adviser for nutrition and food security in the World Health organisation (WHO) Regional Office for Europe said:

"This is an interesting piece of research putting together different lifestyle aspects with food choices. We need more research on the obese environment - the integration between medical research and socio-political research is something we should be exploring more."

There is also a Warwick Universty podcast by Professor Francesco Cappuccio on the health consequnces of a lack of sleep and how you can get more: Link

See also: Sleep and Obesity (research TV)

Warwick University's sleep research news

How many cell types does a person have?

According to recent research published in biological reviews in an adult human it is 411 with 145 of those being neurons.


"Metazoans are composed of a finite number of recognisable cell types. Similar to the relationship between species and ecosystems, knowledge of cell type diversity contributes to studies of complexity and evolution. However, as with other units of evolution, the cell type often resists definition. This review proposes guidelines for characterising cell types and discusses cell homology and the various developmental pathways by which cell types arise, including germ layers, blastemata (secondary development/neurulation), stem cells, and transdifferentiation. An updated list of cell types is presented for a familiar, albeit overlooked model taxon, adult Homo sapiens, with 411 cell types, including 145 types of neurons, recognised. Two methods for organising these cell types are explored. One is the artificial classification technique, clustering cells using commonly accepted criteria of similarity. The second approach, an empirical method modeled after cladistics, resolves the classification in terms of shared features rather than overall similarity. While the results of each scheme differ, both methods address important questions. The artificial classification provides compelling (and independent) support for the neural crest as the fourth germ layer, while the cladistic approach permits the evaluation of cell type evolution. Using the cladistic approach we observe a correlation between the developmental and evolutionary origin of a cell, suggesting that this method is useful for predicting which cell types share common (multipotential) progenitors. Whereas the current effort is restricted by the availability of phenotypic details for most cell types, the present study demonstrates that a comprehensive cladistic classification is practical, attainable, and warranted. The use of cell types and cell type comparative classification schemes has the potential to offer new and alternative models for therapeutic evaluation."

Human cell type diversity, evolution, development, and classification with special reference to cells derived from the neural crest
Matthew K. Vickaryous and Brian K. Hall
Biological Reviews, in press, doi: 10.1017/S1464793106007068, Published online 22 Jun 2006