27 August, 2008

Scorpions as a health problem

Scorpions are infamous because of their venomous sting, but as with many other venomous animals, their reputation is exaggerated. Chippaux & Goyffon has recently presented an analysis of the epidemiology of scorpionism based on published facts, and they list species that are shown in the literature to be dangerous to man.

Here is the abstract of the paper:

The scorpionism is an actual public health problem in several parts of the world because, either incidence, or severity of envenomations is high and managed with difficulty by health services, or for these two reasons at the same time. The treatment of scorpion envenomation is complex and controversial, in particular regarding the utility of the antivenoms and symptomatic treatments that must be associated. The authors reviewed the literature of last 30 years to discuss the epidemiologic importance of the scorpionism and to point out the principal therapeutic or preventive measures. According to the most recent studies, seven areas were identified as at risk: north-Saharan Africa, Sahelian Africa, South Africa, Near and Middle-East, South India, Mexico and South Latin America, east of the Andes. These involve 2.3 billion at risk population. The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%). Although adults are more often concerned, children experience more severe envenomations and among them, mortality is higher. Improvement of therapeutic management would reduce the lethality very significantly.

Even though this is a thorough review of the medical literature, I do not think that this is a final answer to the questions about which scorpions are really dangerous.

Chippaux JP, Goyffon M. Epidemiology of scorpionism: A global appraisal. Acta Trop. 2008;107(2):71-9.[Subscription required for fulltext]

23 August, 2008

A new species in the genus Vachoniochactas from Colombia

A new species in the little known chactid genera Vachoniochactas has been described from Colombia, bringing the number of species in the genus up to four.

Vachoniochactas humboldti Florez, Botero-Trujillo & Acosta, 2008 [Chactidae]

This small scorpion (20-25 mm) is probably a leaf litter dweller.

The status of the genus is also discussed.

Florez E, Botero-Trujillo R, Acosta LE. Descritpion of Vachoniochactas humboldti sp. nov. from Colombia, with complementary notes on the genus (Scorpiones, Chactidae). Zootaxa. 2008(1853):31-44.

Family Chactidae

15 August, 2008

How to keep Australian scorpions

Mark Newton, the editor of the great Aussi scorpion site, The spiral Burrow, has published a book about Aussi scorpions and their husbandery.

In addition to information about how to keep Aussi scorpions, the book also has a lot of general information about scorpions and their biology. The book has several color plates. ISBN number is 978-0-9804161-0-7.

I haven't received the book yet, but based on the information and previews on the book's promo page and my previous experiences with the author, I'm convinced that this will be a very interesting and informative book.

Australian scorpions are rarely available outside Australia due to the country's strict policy on animal exports, and this book is a great opportunity to get an insight into the scorpion fauna of Australia.

The book can be ordered from the book's promo page. PayPal payment is possible.

07 August, 2008

Are female scorpions better desert survivors than males?

It is well known that desert scorpions are among the best adapted arthropods inhabiting the warm and dry deserts of the world. Scorpions exhibit some of the lowest water-loss rates recorded for arthropods, and also have strategies for either tolerating increased haemolymph osmolarity or regulating the volum and consentration of the body fluid.

In a recent paper, Gefen (2008) shows that female Smeringurus mesaensis (Vaejovidae) actually is better than males in handling the though conditions in a desert environment. The females had larger hepatopancreas compared to males, and showed a considerably better osmoregulatory capacity. Females had higher hepatopancreas water content and higher mobilization rates of water from the hepatopancreas to the haemolymph during deccication.

Here is the abstract from the article:

The osmoregulatory and respiratory responses of male and female Smeringurus mesaensis (Vaejovidae) to prolonged desiccation were measured. No significant effect of sex on mass-loss rates (MLRs) was found. Still, females maintained their haemolymph osmolality when desiccated to 10% mass loss, whereas that of males increased significantly after loss of as little as 5% of initial mass. Females had a 3-fold larger hepatopancreas, significantly higher hepatopancreas water content and higher metabolic rates when adjusted to hepatopancreas-free dry mass. Thus, females not only store more water in the hepatopancreas but also mobilise it to the haemolymph at a higher rate during desiccation, thus maintaining haemolymph osmolality.

Gas exchange rates of both males and females decrease as desiccation progresses. An initial respiratory exchange ratio (RER) of 0.9 is followed by a significant increase at mass loss levels of 7.5% and higher. RER values greater than 1.0 may result from partial shift to anaerobic catabolism, which allows closure of the book lung spiracles for longer duration, thus minimising respiratory water loss.

The effects of gas exchange rates on rates of water mobilisation between body compartments and water loss to the environment suggest a trade-off between maintaining osmotic stability and conserving body water stores under stressful conditions.

Gefen E. Sexual dimorphism in desiccation responses of the sand scorpion Smeringurus mesaensis (Vaejovidae). J Insect Physiol. 2008;54(5):798-805. [Subscription required for fulltext]

05 August, 2008

Taxonomical updates

Three new papers has recently been published with new species and taxonomical updates:

Teruel & Roncallo (2008):

Ananteris hasshy Teruel & Roncallo, 2008 (Buthidae) from Colombia (new species).

Teruel & Rodriguez (2008):

Didymocentrus armasi Rolando & Rodriguez, 2008 (Scorpionidae) from Cuba (new species).
Didymocentrus jaumei Armas, 1976 (Scorpionidae) from Cuba (restored species status).
Didymocentrus sanfelipensis Armas, 1976 (Scorpionidae) from Cuba (restored species status).

Lourenço, Qi & Goodman (2008):

Tityobuthus betschi Lourenço, Qi & Goodman, 2008 (Buthidae) from Madagascar (new species).
Tityobuthus chelbergorum Lourenço, Qi & Goodman, 2008 (Buthidae) from Madagascar (new species).
Tityobuthus mccarteri Lourenço, Qi & Goodman, 2008 (Buthidae) from Madagascar (new species).

This paper also has a historical review of the genus Tityobuthus and a redescription of Tityobuthus baroni (Pocock, 1890).

In other news:

Lourenco (2008) has described the male of Chaerilus agilis Pocock, 1899 from Malaysia.

Teruel (2008) has confirmed the occurence of Centruroides gracilis (Latreille, 1805) in Jamaica.

The gallery of the Scorpion Files has recently been updated with several new pictures of rarly seen species. A big thanks to all that have submitted pictures to the Scorpion Files!

Teruel R, Roncallo CA. A new species of Ananteris Thorell, 1891 (Scorpiones: buthidae) from the Caribbean region of Colombia. Euscorpius. 2008(72):1-7. [Free fulltext]

Teruel R, Rodriguez TM. La subfamilia Diplocentrinae (Scorpiones: Scorpionidae) en Cuba. Quinta parte: el genero Didymocentrus Kraepelin 1905. Boletin Sociedad Entomológica Aragonesa. 2008(42):53-78. [No fulltext]

Lourenco WR, Qi JX, Goodman SM. The identity of Tityus baroni (Pocock, 1890) (Scorpiones, Buthidae) and description of three new species from Madagascar. Boletin Sociedad Entomológica Aragonesa. 2008(42):89-102. [No fulltext]

Lourenco WR. Description de mâle de Chaerilus agilis Pocock, 1899 (Scorpiones, Chaerilidae). Boletin Sociedad Entomológica Aragonesa. 2008(42):139-42. [No fulltext]

Teruel R. Confirmation of the occurence of Centruroides gracilis (Latreille 1805) (Scorpiones: Buthidae) in Jamaica. Boletin Sociedad Entomológica Aragonesa. 2008(42):370. [No fulltext]

Family Buthidae
Family Scorpionidae
Family Chaerilidae