Back to Tityus serrulatus Lutz & Mello, 1922 (Scorpiones: Buthidae): new comments about an old species

A synopsis on the historical, geographical and ecological aspects related to the most conspicuous scorpion species of the genus Tityus known from Brazil is proposed. Tityus serrulatus Lutz & Mello, 1922 was described precisely one century ago, nevertheless many questions related to its ecological adaptations and geographical expansion remain without a precise response. This species, well known for its infamous reputation of noxious species, is also known for its capacity to reproduce asexually, by parthenogenesis. Although the individuals of a given population are considered clones, a new hypothesis could suggest the occurrence of mutations within isolated individuals, leading to distinct subpopulations that could present better phenotypic performances in ecological habitats distinct from those of the original area of distribution of the species.(AU)

Transcriptomic and proteomic analyses of venom glands from scorpions Liocheles australasiae, Mesobuthus martensii, and Scorpio maurus palmatus.

Scorpion venom contains a cocktail of differing peptides and proteins. Previous studies focused on the identification of species-specific components in scorpion venoms, and whether there could be peptides and/or proteins conserved in the venom gland of a scorpion ancestor has been rarely investigated. Here, using a combination of transcriptomic and proteomic approaches, putative conserved toxins from the venom glands of scorpions Liocheles australasiae, Mesobuthus martensii, and Scorpio maurus palmatus were identified and compared. Similar to other studies, more than half of the conserved toxins are predominantly proteins including proteases. On the other hand, unique venom peptides, including ion channel toxins were revealed specifically in the M. martensii. The sodium channel toxin peptides revealed in M. martensii consolidated that scorpions in the Buthidae are able to envenomate their prey wih highly neurotoxic venom. This study suggested that these conserved proteins had already formed part of the arsenal in the venom gland of the common ancestor of scorpions, and likely perform important functional roles in envenomation during scorpion evolution.

Karyotype evolution and preliminary molecular assessment of genera in the family Scorpiopidae (Arachnida: Scorpiones).

The scorpions represent an ancient and morphologically conserved order of arachnids. Despite that, their karyotypes may differ considerably even among closely related species. In this study, we identify the trends of the karyotype evolution in the family Scorpiopidae based on integrating cytogenetic data and multi-locus molecular phylogenetic approaches. We detected considerable variability in diploid numbers of chromosomes (from 48 to 147), 18S rRNA gene cluster positions (from terminal to pericentromeric) at the interspecific level. Moreover, we identified independent fusions, fissions and inversions in the evolution of the family Scorpiopidae, leading to a remarkable diversification of the karyotypes. The dynamic system of the karyotype changes in this group is further documented by the presence of interstitial telomeric sequences (ITS) in two species. The cytogenetic differences observed among the analyzed species highlight the potential of this type of data for species-level taxonomy in scorpion lineages with monocentric chromosomes. Additionally, the results of our phylogenetic analyses support the monophyly of the family Scorpiopidae, but rendered several genera para- or polyphyletic.

Scorpion species of medical importance in the Brazilian Amazon: a review to identify knowledge gaps

Scorpionism is a relevant medical condition in Brazil. It is responsible for most accidents involving venomous animals in the country, which leads to severe symptoms that can evolve to death. In recent years, an increase of almost 50% in the incidence of scorpionism has been observed in the Northern Region, where the highest severity of envenoming has been notified since the beginning of the 21st century. This review aims to provide an in-depth assessment of public data and reports on symptoms and epidemiology of envenoming, ecological aspects of scorpions, and characterization of venoms and toxins to access the gaps that need to be filled in the knowledge of the scorpion species of medical importance from the Brazilian Amazon. A systematic search using the string words "Amazon" and "scorpion" was performed on 11 databases. No restriction on date, language or status of the publication was applied. Reports not related to the Brazilian Amazon were excluded. Therefore, 88 studies remained. It is shown that populations of scorpions of medical importance, even of the same species, may present significant toxic variations peculiar to some regions in the Brazilian Amazon, and commercial scorpion antivenoms were not able to shorten the intensity and duration of neurological manifestations in patients stung by T. silvestris, T. apiacas or T. obscurus. It is also highlighted that the toxins responsible for triggering these alterations have not been elucidated yet and this is a fruitful field for the development of more efficient antivenoms. Furthermore, the geographic distribution of scorpions of the genus Tityus in the Brazilian Amazon was revised and updated. The cumulative and detailed information provided in this review may help physicians and scientists interested in scorpionism in the Brazilian Amazon.(AU)

First report of scorpionism caused by Tityus serrulatus, described by Lutz and Mello, 1922 (Scorpiones, Buthidae), a species non-native to the state of Pará, Brazilian Amazon

Abstract This reports a case of scorpionism caused by Tityus serrulatus. A male adult was stung while unloading bananas at the supply center in Belém, Pará, Brazil. The bananas originated in another state (Bahia) and were brought to Belém by truck. The patient presented with pain, edema, and erythema at the sting site, and was classified as low-risk. The specimen was identified as T. serrulatus and symptomatic treatment and clinical observation were advised. The patient was discharged later without further complications. This is the first known envenomation caused by T. serrulatus, a non-native species to Pará, in the Brazilian Amazon.

Expansión de la distribución de escorpiones del género Tityus C. L. Koch 1836 en Argentina: Implicancias sanitarias / Expansion of the distribution of scorpions of the genus Tityus C. L. Koch 1836 in Argentina: Implications in public health

Se ha observado la presencia de especies de Tityus en diferentes regiones del país, en las cuales su presencia no había sido comunicada previamente: 1- Tityus bahiensis en las provincias de Entre Ríos y Buenos Aires, en esta última en la localidad de Lanús y en San Clemente del Tuyú, y 2- Tityus confluens en la Ciudad Autónoma de Buenos Aires (CABA) y en la provincia de Buenos Aires en las localidades de Pilar, La Plata, Mar del Plata y Bahía Blanca. Estos hallazgos modifican el mapa de la distribución de escorpiones de importancia sanitaria en Argentina por lo que ante la picadura de escorpiones deben considerarse estos nuevos hallazgos. Esto es especialmente importante en el ámbito de la CABA y la provincia de Buenos Aires, en donde la enorme mayoría de los accidentes por escorpiones han sido causados por T. trivittatus y en donde ahora, al menos en algunas de sus regiones se pueden encontrar T. confluens y T. bahiensis. Se discuten posibles razones de esta nueva distribución así como la ocurrencia de accidentes graves en zonas donde no ocurrían históricamente y de sus posibles causas. En base a los casos graves producidos en los últimos tiempos y a este nuevo mapa de distribución, se hace énfasis en la necesidad de capacitación al personal de salud en general y de los médicos de guardia y terapistas en particular, para tratar adecuadamente los accidentes por escorpiones.

Several species of Tityus have been described in regions of Argentina where their presence had not been previously described. These are: 1- Tityus bahiensis in the provinces of Entre Ríos and Buenos Aires (in the localities of Lanús and San Clemente del Tuyú), and 2- Tityus confluens in the city of Buenos Aires and in the province of Buenos Aires in the localities of Pilar, La Plata, Mar del Plata and Bahía Blanca. These findings modify the distribution map of scorpions of sanitary importance in Argentina, reason for which this new distribution must be considered when facing a scorpion sting. This is especially important in the city of Buenos Aires and the province of Buenos Aires, where most of the accidents by scorpions are caused by Tityus trivittatus, and where at least in some of their regions, T. confluens or T. bahiensis can be found at present. The possible reasons of this new distribution, as well as the possible causes for the occurrence of severe envenomations in regions where these were not observed historically, are discussed. Based on the severe envenomations observed and on this new distribution map, emphasis is placed on the need to capacitate health personnel in general and intensivists or critical care physicians in particular to adequately treat scorpion accidents.

Venoms of Iranian Scorpions (Arachnida, Scorpiones) and Their Potential for Drug Discovery.

Scorpions, a characteristic group of arthropods, are among the earliest diverging arachnids, dating back almost 440 million years. One of the many interesting aspects of scorpions is that they have venom arsenals for capturing prey and defending against predators, which may play a critical role in their evolutionary success. Unfortunately, however, scorpion envenomation represents a serious health problem in several countries, including Iran. Iran is acknowledged as an area with a high richness of scorpion species and families. The diversity of the scorpion fauna in Iran is the subject of this review, in which we report a total of 78 species and subspecies in 19 genera and four families. We also list some of the toxins or genes studied from five species, including Androctonus crassicauda, Hottentotta zagrosensis, Mesobuthus phillipsi, Odontobuthus doriae, and Hemiscorpius lepturus, in the Buthidae and Hemiscorpiidae families. Lastly, we review the diverse functions of typical toxins from the Iranian scorpion species, including their medical applications.

Phylogenomics facilitates stable scorpion systematics: Reassessing the relationships of Vaejovidae and a new higher-level classification of Scorpiones (Arachnida).

The Neartic family Vaejovidae (Scorpiones: Chactoidea) has long been treated as a diverse and systematically cohesive group of scorpions, but its monophyly and relationship to other scorpion families have historically been questioned. Morphological data have supported its monophyly and a variety of phylogenetic placements within the superfamily Chactoidea. Recent phylogenomic analyses have instead recovered vaejovids as polyphyletic (albeit with minimal taxonomic sampling) and Chactoidea as paraphyletic. Here, we reexamined the monophyly and phylogenetic placement of the family Vaejovidae, sampling 17 new vaejovid libraries using high throughput transcriptomic sequencing. Our phylogenomic analyses revealed a previous misplacement of Smeringurus mesaensis. Regardless, we recovered Vaejovidae as diphyletic due to the placement of the enigmatic genus Uroctonus. The remaining vaejovids formed a clade that was strongly supported as the sister group of the superfamily Scorpionoidea, a placement insensitive to matrix completeness or concatenation vs. species tree approaches to inferring the tree topology. Chactoidea was invariably recovered as a paraphyletic group due to the nested placement of Scorpionoidea. As first steps to resolving the paraphyly of Chactoidea, we take the following systematic actions: (1) we establish the superfamily Superstitionoidea (new superfamily) to accommodate Superstitioniidae; (2) we restore Vaejovoidea (status revalidated) as a valid superfamily that excludes Uroctonus; and (3) we treat the families Caraboctonidae, Troglotayosicidae, and the subfamily Uroctoninae as incertae sedis with respect to superfamilial placement. Our systematic actions thus establish the monophyly of the presently redefined Chactoidea and Vaejovoidea.

Proteomic endorsed transcriptomic profiles of venom glands from Tityus obscurus and T. serrulatus scorpions.

BACKGROUND: Except for the northern region, where the Amazonian black scorpion, T. obscurus, represents the predominant and most medically relevant scorpion species, Tityus serrulatus, the Brazilian yellow scorpion, is widely distributed throughout Brazil, causing most envenoming and fatalities due to scorpion sting. In order to evaluate and compare the diversity of venom components of Tityus obscurus and T. serrulatus, we performed a transcriptomic investigation of the telsons (venom glands) corroborated by a shotgun proteomic analysis of the venom from the two species. RESULTS: The putative venom components represented 11.4% and 16.7% of the total gene expression for T. obscurus and T. serrulatus, respectively. Transcriptome and proteome data revealed high abundance of metalloproteinases sequences followed by sodium and potassium channel toxins, making the toxin core of the venom. The phylogenetic analysis of metalloproteinases from T. obscurus and T. serrulatus suggested an intraspecific gene expansion, as we previously observed for T. bahiensis, indicating that this enzyme may be under evolutionary pressure for diversification. We also identified several putative venom components such as anionic peptides, antimicrobial peptides, bradykinin-potentiating peptide, cysteine rich protein, serine proteinases, cathepsins, angiotensin-converting enzyme, endothelin-converting enzyme and chymotrypsin like protein, proteinases inhibitors, phospholipases and hyaluronidases. CONCLUSION: The present work shows that the venom composition of these two allopatric species of Tityus are considerably similar in terms of the major classes of proteins produced and secreted, although their individual toxin sequences are considerably divergent. These differences at amino acid level may reflect in different epitopes for the same protein classes in each species, explaining the basis for the poor recognition of T. obscurus venom by the antiserum raised against other species.

Venoms of Centruroides and Tityus species from Panama and their main toxic fractions.

The scorpionism in Panama is notorious for the confluence and coexistence of buthid scorpions from the genera Centruroides and Tityus. This communication describes an overview of the larger representative toxic venom fractions from eight dangerous buthid scorpion species of Panama: Centruroides (C. granosus, C. bicolor, C. limbatus and C. panamensis) and Tityus (T. (A.) asthenes, T. (A.) festae, T. (T.) cerroazul and T. (A.) pachyurus). Their venoms were separated by HPLC and the corresponding sub-fractions were tested for lethality effects on mice and insects. Many fractions toxic to either mice or insects, or both, were found and have had their molecular masses determined by mass spectrometry analysis. The great majority of the lethal components had a molecular mass close to 7000 Da, assumed to be peptides that recognize Na+-channels, responsible for the toxicity symptoms observed in other buthids scorpion venoms. A toxic peptide isolated from the venom of T. pachyurus was sequenced by Edman degradation, allowing the synthesis of nucleotide probe for cloning the correspondent gene. The mature toxin based on the cDNA sequencing has the C-terminal residue amidated, contains 62 amino acid packed by 4 disulfide linkages, with molecular mass of 7099.1 Da. This same toxic peptide seems to be present in scorpions of the species T. pachyurus collected in 5 different regions of Panama, although the overall HPLC profile is quite different. The most diverse neurotoxic venom components from the genus Centruroides were found in the species C. panamensis, whereas T. cerroazul was the one from the genus Tityus. The most common neurotoxins were observed in the venoms of T. festae, T. asthenes and T. pachyurus with closely related molecular masses of 7099.1 and 7332 Da. The information reported here is considered very important for future generation of a neutralizing antivenom against scorpions from Panama. Furthermore, it will contribute to the growing interest in using bioactive toxins from scorpions for drug discovery purposes.

The evolution and distribution of noxious species of scorpions (Arachnida: Scorpiones)

This contribution attempts to bring some general information on the evolution and, in particular, on the geographic distribution of scorpion species noxious to humans. Since 95% of the scorpions incidents are generated by specimens of the family Buthidae C. L. Koch, the analysis will be limited to this familial group. As in previous similar contributions, the content of this work is mostly addressed to non-specialists whose research embraces scorpions in several fields such as venom toxins and public health. Only in recent years, efforts have been made to create better links between 'academic scorpion experts' and other academic non-specialists who use scorpions in their research. Even if a larger progress can yet be expected from such exchanges, crossed information proved to be useful in most fields of scorpion studies. Since the taxonomy of scorpions is complex, misidentifications and even more serious errors concerning scorpion classification/ identification are often present in the general literature. Consequently, a precise knowledge of the distribution patterns presented by many scorpion groups and, in particular, those of infamous species, proves to be a key point in the interpretation of final results, leading to a better treatment of the problems caused by infamous scorpion species.(AU)

Implication of Tityus apiacas (Lourenco, 2002) in scorpion envenomations in the Southern Amazon border, Brazil

Abstract Herein, four cases of scorpion stings caused by Tityus apiacas recorded from the municipality of Apuí, in the southern region of the Brazilian Amazon, are described. Patients showed systemic clinical manifestations, described as unusual, involuntary, and generalized tingling and numbness, reported by patients as an electric shock sensation, lasting up to 24 hours after the sting. All patients described local pain and sensation, along with other clinical symptoms including local edema and erythema. Systemic manifestations were not life threatening. Antivenom therapy was administered to all patients, who were discharged without complaints.

Escorpiones y escorpionismo en la provincia de Jujuy / Scorpions and scorpionism in the province of Jujuy

En Sudamérica los escorpiones que revisten importancia sanitaria pertenecen a la familia Buthidae y al género Tityus. En Argentina existen seis especies: T. trivittatus Kraepelin, T. confluens Borelli, T. bahiensis (Perty), T. argentinus Borelli, T. paragua­yensis Kraepelin y T. uruguayensis Borelli, de las cuales sólo las tres primeras demostraron poseer venenos tóxicos capaces de ocasionar accidentes fatales. En Jujuy la especie más importante fue T. confluens y recientemente se registró T. trivittatus. También está presente T. argentinus, que hasta el momento, no reviste riesgo sanitario. Los objetivos del presente trabajo fueron identificar los escorpiones del género Tityus (Buthidae), obtenidos en cinco instituciones de referencia de la provincia de Jujuy, conocer su distribución, abundancia, estacionalidad y relación con variables climáticas en dos eco-regiones (Valles y Yungas); ámbito de ocurrencia de hallazgos y accidentes, horario de los mismos y características epidemiológicas de los accidentados (edad, sexo, óbitos). El periodo considerado fue octubre 2013 a septiembre 2014. Se registraron los accidentes y hallazgos de escorpiones de las instituciones de la ciudad capital con área de influencia en la región Valles y aquellas del interior provincial con área de influencia en la región Yungas. Se analizaron 422 ejemplares de escorpiones. Las especies presentes fueron Tityus argentinus, T. trivittatus y T. confluens; esta última dominó en Yungas. El mayor número de registros de T. trivittatus se obtuvo en la ciudad de San Pedro de Jujuy. En la región Valles, T. argentinus fue la especie dominante. La mayor cantidad de accidentes y hallazgos de escorpiones se registró por la mañana y en los meses cálidos con valores máximos de abundancia en diciembre. Si se considera el ámbito de ocurrencia predominaron los accidentes y hallazgos intradomiciliarios (92%); el dormitorio fue el lugar más mencionado (46%). Entre los accidentados predominó el sexo femenino (66%). La franja etaria más afectada fue la de los adultos (75%), en particular el rango 26-35 años; en la franja pediátrica el mayor número de accidentes se produjo en niños mayores de 7 años. No se registraron óbitos. El conocimiento de la distribución espacial y temporal de T. confluens sumada al ingreso y colonización de T. trivittatus convierten a la provincia de Jujuy en un área de mayor riesgo, siendo necesaria una estricta vigilancia epidemiológica de los casos de escorpionismo. Este es el primer estudio que integra aspectos taxonómicos y epidemiológicos en esta provincia.

In South America the scorpions that are of health care importance belong to the Buthidae family and to the Tityus genus. There are six species in Argentina: T. trivittatus Kraepelin, T. confluens Borelli, T. bahiensis (Perty), T. argentinus Borelli, T. paraguay­ensis Kraepelin and T. uruguayensis Borelli, of which only the first three demostrated to possess toxic poisons capable of causing fatal accidents. T. confluens is the most important species in Jujuy and T. trivittatus has been recently recorded. Also present is T. argentinus, which has not posed a health risk to date. The objectives of the present work were to identify scorpions of the Tityus (Buthidae) genus received at five reference institutions in the province of Jujuy, to identify their distribution, abundance, seasonality and relation with climatic variables in two eco-regions (Valles and Yungas), area of occurrence of findings and accidents, their sched­ule and epidemiological characteristics of the victims (age, sex, deaths). The period considered was from October 2013 to Septem­ber 2014. Accidents and findings of scorpions from the institutions of the capital city with area of influence in the valleys region and those of the provincial interior with area of influence in the Yungas region were recorded. 422 specimens of scorpions were analyzed. The species present were Tityus argentinus, T. trivittatus and T. confluens; the latter dominated in Yungas. The highest number of T. trivittatus records was obtained in the city of San Pedro de Jujuy. In the Valles region, T. argentinus was the dominant species. The largest number of accidents and scorpion finds were recorded in the morning and in warm months with maximum abundance values in december. Considering the scope of occurrence, 92% of scorpion findings and accidents predominated intradomiciliarly. The bedroom was the most mentioned place (46%). Among the victims, the female sex predominated (66%). The most affected age group was that of adults (75%), in particular the range 26-35 years. In the pediatric group, the greatest number of accidents occurred in children older than 7 years. No deaths were recorded. The knowledge of the spatial and temporal distribution of T. confluens plus the entrance and colonization of T. trivittatus make the province of Jujuy an area of greater risk, requiring a strict epidemiological surveillance of scorpionism cases. This is the first study that integrates taxonomic and epidemiological aspects in this province.

Scorpionism by Tityus silvestris in eastern Brazilian Amazon

Scorpionism is a serious public health problem in Brazil. Although cases of envenomation by scorpions are frequent in Brazil, Tityus silvestris found throughout the Amazon region is considered of minor medical significance and with only a few descriptions in the literature. This article aims to describe for the first time the epidemiological characteristics and clinical manifestations of scorpion stings by T. silvestris that occurred in eastern Brazilian Amazon. Methods A prospective and observational study was carried out on 13 confirmed cases of T. silvestris envenomation registered from 2007 to 2011 in the cities of Belém and Ananindeua, Pará state, Brazil. Results The stings occurred mainly during daytime, at domiciliary environment, and the scorpions were found in clothing, fruits or vegetables. Envenomation was more frequent in the age group between 21 and 30 years old, upper limbs were more affected and medical aid was usually provided within two hours. Men and women were equally affected. Regarding severity, ten patients were classified as Class I and three patients as Class II according to the Scorpion Consensus Expert Group. Local manifestations were present in all patients, being pain the most common symptom. Mild systemic manifestations including nausea, vomiting, somnolence, malaise and prostration were observed in three victims. Symptomatic treatment of pain was offered to all patients, and only one received specific antivenom. All victims had a favorable outcome. Conclusions To the best of our knowledge, this study is the first to report the systemic symptomatology of envenomation by T. silvestris in the Brazilian Amazon, highlighting the medical relevance of the species in this region. Further research on the venom and clinical manifestations of envenomation by T. silvestris should be conducted in order to verify the relevance of this species to public health.

Biochemical, transcriptomic and proteomic analyses of digestion in the scorpion Tityus serrulatus: insights into function and evolution of digestion in an ancient arthropod.

Scorpions are among the oldest terrestrial arthropods and they have passed through small morphological changes during their evolutionary history on land. They are efficient predators capable of capturing and consuming large preys and due to envenomation these animals can become a human health challenge. Understanding the physiology of scorpions can not only lead to evolutionary insights but also is a crucial step in the development of control strategies. However, the digestive process in scorpions has been scarcely studied. In this work, we describe the combinatory use of next generation sequencing, proteomic analysis and biochemical assays in order to investigate the digestive process in the yellow scorpion Tityus serrulatus, mainly focusing in the initial protein digestion. The transcriptome generated database allowed the quantitative identification by mass spectrometry of different enzymes and proteins involved in digestion. All the results suggested that cysteine cathepsins play an important role in protein digestion. Two digestive cysteine cathepsins were isolated and characterized presenting acidic characteristics (pH optima and stability), zymogen conversion to the mature form after acidic activation and a cross-class inhibition by pepstatin. A more elucidative picture of the molecular mechanism of digestion in a scorpion was proposed based on our results from Tityus serrulatus. The midgut and midgut glands (MMG) are composed by secretory and digestive cells. In fasting animals, the secretory granules are ready for the next predation event, containing enzymes needed for alkaline extra-oral digestion which will compose the digestive fluid, such as trypsins, astacins and chitinase. The digestive vacuoles are filled with an acidic proteolytic cocktail to the intracellular digestion composed by cathepsins L, B, F, D and legumain. Other proteins as lipases, carbohydrases, ctenitoxins and a chitolectin with a perithrophin domain were also detected. Evolutionarily, a large gene duplication of cathepsin L occurred in Arachnida with the sequences from ticks being completely divergent from other arachnids probably due to the particular selective pressures over this group.

A checklist of the scorpions of Ecuador (Arachnida: Scorpiones), with notes on the distribution and medical significance of some species

Ecuador harbors one of the most diverse Neotropical scorpion faunas, hereby updated to 47 species contained within eight genera and five families, which inhabits the Costa (n= 17), Sierra (n= 34), Oriente (n= 16) and Insular (n= 2) biogeographical regions, corresponding to the western coastal, Andean, Amazonian, and the Galápagos archipelago regions, respectively. The genusTityus Koch, in the family Buthidae, responsible for severe/fatal accidents elsewhere in northern South America and the Amazonia, is represented in Ecuador by 16 species, including T. asthenes, which has caused fatalities in Colombia and Panama, and now in the Ecuadorian provinces of Morona Santiago and Sucumbíos. Underestimation of the medical significance of scorpion envenoming in Ecuador arises from the fact thatCentruroides margaritatus (Gervais) (family Buthidae) andTeuthraustes atramentarius Simon (family Chactidae), whose venoms show low toxicity towards vertebrates, frequently envenom humans in the highly populated Guayas and Pichincha provinces. This work also updates the local scorpion faunal endemicity (74.5 %) and its geographical distribution, and reviews available medical/biochemical information on each species in the light of the increasing problem of scorpionism in the country. A proposal is hereby put forward to classify the Ecuadorian scorpions based on their potential medical importance.

Identificación de los escorpiones de importancia médica en la Argentina / Identification of scorpions with medical importance in Argentina

. Los escorpiones de importancia médica en el mundo pertenecen mayoritariamente a la familia Buthidae. En Argentina, los miembros de esta familia no son numerosos, siendo mucho mayor el número de especies de la familia Bothriuridae, cuyos miembros hasta el momento no revisten importancia médica. Dentro de los tres géneros de Buthidae que viven en el país, el género Tityus es el que posee especies cuya picadura e inoculación de veneno puede provocar accidentes severos. En general, la diferenciación entre Tityus trivittatus, el escorpión de mayor importancia médica de Argentina, respecto a otros escorpiones, es fácil en las provincias de la zona central del país. Sin embargo, las reglas a utilizar para la diferenciación entre escorpiones de importancia médica de aquellos que no la tienen, no son similares en todo el país. En esta actualización, se brindan elementos sencillos y claros para que el personal de salud pueda diferenciar entre las especies de Tityus de importancia médica de los escorpiones de la familia Bothriuridae, ampliamente distribuidos en la superficie del país. De esta forma, se espera que el diag­nóstico acertado sobre la especie de escorpión pueda mejorar la atención en el caso de la picadura por animales potencialmente peligrosos. Por otro lado, permitirá diferenciar a los escorpiones sin importancia médica lo que redundará en la mejor utilización de los recursos disponibles en los niveles de atención primaria, ante la emergencia que representa una picadura de alacrán.

The scorpions of medical importance in the world mostly belong to Buthidae family. In Argentina, members of this family are not numerous, being much most numerous the species from the Bothriuridae family, whose members so far are of no medical importance. Within the three genera of Buthidae that inhabit in the country, only species from Tityus genus can cause severe ac­cidents. The differentiation between the scorpions of highest medical importance in Argentina (Tityus trivittatus), regarding other scorpions, is easy in the provinces of the central region. However, the rules used for the differentiation of medically important scorpions regarding those not dangerous, is not similar through the country. In this update, we provide simple and clear tools for the health personnel to differentiate between species of Tityus with medical importance and the scorpions from Bothriuridae fam­ily, widely distributed in the country. Thus it is expected that the accurate diagnosis of the species of scorpions may improve the attention in the case of the sting of potentially dangerous scorpions. On the other hand, the differentiation of the not dangerous scorpions from those with medical importance will result in the best use of the available resources in primary care level, consider­ing the emergency that represents a scorpion sting.

A historical approach to scorpion studies with special reference to the 20 th and 21st centuries

This work provides historical context about scorpion studies from the end of the 19 th century to the present day. The content is mainly addressed to non-zoologists, working in research fields that embrace scorpion biology, notably to those working with venoms and toxins. The historical aspects described include academic professional scholars who worked on scorpion classification and general distribution patterns; and to a lesser extent, on studies of ecology and natural history. The aim is not to provide an exhaustive description of all scholars who in one way or another became involved with scorpions, but rather of those who greatly contributed during a given period to the research of these organisms. No critical analysis of the work of previous researchers is undertaken, but some comments are proposed to bring clarification on ‘who’s who’. Since a global consensus in relation to classification and/or distribution patterns has not been reached among modern experts, these different approaches are also presented without judgment. Consequently, distinct approaches remain open for discussion.

Mild reproductive effects of the Tityus bahiensis scorpion venom in rats

Scorpion envenoming is a public health problem in Brazil, where Tityus serrulatus and T. bahiensis are considered the most dangerous scorpions. They are well adapted to urbanized environments, and there is an increasing probability of human exposure to these venoms, including during pregnancy. Not much is known about the effects of prenatal exposure to the venom, and no information is available to aid in the rational treatment of victims stung during pregnancy. Thus, this study aimed to investigate whether venom from the scorpion T. bahiensis administered once to pregnant female rats at a dose that causes a moderate envenomation may lead to deleterious effects on the reproductive performance of the dams and on the development of their offspring. This is the first work demonstrating that T. bahiensis venom, when administered experimentally to rats, alters maternal reproductive performance and the morphological development of fetuses. The venom was given to dams on the 5th (GD5) or on the 10th (GD10) gestational day. After laparotomy, on GD21, fetuses and placentas were counted, weighed and externally analyzed. The corpora lutea were counted. The sex and vitality of fetuses were evaluated, and each litter was then randomly divided for visceral or skeletal analyses. Data were analyzed by ANOVA followed by the Tukey-Kramer test and Fisher's exact test. The significance level for all tests was set at p < 0.05.

A historical approach to scorpion studies with special reference to the 20 th and 21st centuries

This work provides historical context about scorpion studies from the end of the 19 th century to the present day. The content is mainly addressed to non-zoologists, working in research fields that embrace scorpion biology, notably to those working with venoms and toxins. The historical aspects described include academic professional scholars who worked on scorpion classification and general distribution patterns; and to a lesser extent, on studies of ecology and natural history. The aim is not to provide an exhaustive description of all scholars who in one way or another became involved with scorpions, but rather of those who greatly contributed during a given period to the research of these organisms. No critical analysis of the work of previous researchers is undertaken, but some comments are proposed to bring clarification on ‘who’s who’. Since a global consensus in relation to classification and/or distribution patterns has not been reached among modern experts, these different approaches are also presented without judgment. Consequently, distinct approaches remain open for discussion.