24 April, 2012

Morphological and geographical variations in Bothriurus bonarensis from South America

Olivero, Mattoni & Peretti have recently published a paper on the morphological and geographical variations in Bothriurus bonarensis from South America.

Diversification of morphological characteristics among geographically separated populations is particularly important in understanding evolutionary processes and is considered the early stage of allopatric speciation. In the present study, we investigated geographic variation in scorpion populations of Bothriurus bonariensis (Koch 1842). Our principal goal was to compare different populations of this species with regard to its distribution, analyzing somatic and genitalic characters. In Argentina, specimens of B. bonariensis from Entre Rı´os and Corrientes Provinces are dark brown, while specimens from La Pampa have reddish coloration. Scorpions of this species from Brazil and south of Uruguay are totally black. Also, we observed variability in body size, some morphological characteristics of adult specimens (e.g., prosoma length, hand height, hand width, and telson height), and genitalic traits (e.g., hemispermatophore lamina length, basal and distal lamina width, dorsal fold length). Results indicate the presence of evident geographic variation: populations from Argentina show similar morphological patterns that differ from populations from Uruguay. We discuss these data in the context of the current phylogeographical and evolutionary knowledge of this species.

Olivero PA, Mattoni CI, Peretti AV. Morphometry and geographical variation of Bothriurus bonariensis (Scorpiones: Bothriuruidae). J Arachnol. 2012;40(1):113-22. [Subscription required for fulltext, but open access after 12 months]

20 April, 2012

Scorpion fauna of Iran - An update

Karatas, Garkheloo & Ucak have recently published a contribution to the knowledge of the scorpion fauna of Iran.

This study covers 16 species in three families collected from 20 different provinces (ostän) of Iran between the years 2005 and 2007, with a summary of previous studies on Iranian scorpions. C. petriolii is recorded for the first time from East Azerbaijan, Qom ad Urumiyeh provinces; H. zagrosensis from Qazvin Province; I. krali from Qom Province; O. doriae from Hamadan Province. A second record of H. acanthocercus is given where the first record was from Khoozestan Province.

Karataş A, Garkheloo MM, Uçak M. Contribution to the distribution of the scorpions of Iran. Zoology in the Middle East. 2012;55:111-20.

19 April, 2012

Ovulation, fertilization and embryonic development in scorpions - a partial review

Yesterday I blogged about a new and interesting review on scorpion reproduction by professor Michael Warburg. Today, professor Warburg sent me another new review article that he as recently published on scorpion reproduction. The main topics of this publication is ovulation, fertilization and embryonic development in scorpions.

Ovulation, fertilization and both normal and arrested embryonic developments in scorpions, are reviewed and discussed. The importance of all three aspects in scorpion reproduction is discussed from both an evolutionary and an ecological outlook. The number of embryos varies within and among scorpion species and is not related to the female’s mass prior to parturition. There is a certain loss in embryo numbers and not all of them will become juveniles. The significance of this loss is discussed, and future avenues of research are suggested.

Warburg MR. Ovulation, fertilization and embryonic development in scorpions: a partial review. African Entomology. 2012;20(1):60-8. [Subscription required for fulltext]

Thanks to professor Warburg for sending me this paper!

18 April, 2012

A review on scorpion reproduction

We still do not know enough about scorpion reproduction. Professor Michael Warburg is one of the leading experts on this topic and he has previously published several important papers on this topic (e.g. the recent The Female reproduction system in scorpions - a review and A review of scorpion reproductive strategies).

This time he has published a very interesting paper reviewing and discussing mating, insemination, gestation, modes of reproduction, parurition, breeding season and birth in scorpions. Professor Warburg also discuss future research of scorpion reproduction in this paper.

Although scorpions are an ancient group their method of reproduction is rather complex and poorly studied. This review aims at clarifying some of the aspects of their reproduction that are important for understanding the reproductive ecology of other arthropods, including insects. The following aspects of scorpion reproduction are discussed and reviewed: mating, insemination, fertilization, gestation, parturition and birth. The onset of gestation and its duration are difficult to determine as both depend on the time of fertilization, for which there are no accurate estimates. There are only a few records of the time between birth and emergence of a larva from the maternal envelope in apoikogenic scorpions, which is important for a better understanding of ovoviviparity. All these questions are important as the answers will greatly enhance our understanding of the population ecology of scorpions in terms of the recruitment rates of cohorts and their chances of survival.

Warburg MR. Pre- and post-parturial aspects of scorpion reproduction. European Journal of Entomology. 2012;109:139-46.

Thanks to Matt Simon for informing me about this paper and to professor Warburg for sending it to me!