Academic literature on the topic 'Thomisoidea'

Envenomation by Loxosceles spiders (Sicariidae family) has been thoroughly documented. However, little is known about the potential toxicity of members from the Sicarius genus. Only the venom of the Brazilian Sicarius ornatus spider has been toxicologically characterized. In Chile, the Sicarius thomisoides species is widely distributed in desert and semidesert environments, and it is not considered a dangerous spider for humans. This study aimed to characterize the potential toxicity of the Chilean S. thomisoides spider. To do so, specimens of S. thomisoides were captured in the Atacama Desert, the venom was extracted, and the protein concentration was determined. Additionally, the venoms were analyzed by electrophoresis and Western blotting using anti-recombinant L. laeta PLD1 serum. Phospholipase D enzymatic activity was assessed, and the hemolytic and cytotoxic effects were evaluated and compared with those of the L. laeta venom. The S. thomisoides venom was able to hydrolyze sphingomyelin as well as induce complement-dependent hemolysis and the loss of viability of skin fibroblasts with a dermonecrotic effect of the venom in rabbits. The venom of S. thomisoides showed intraspecific variations, with a similar protein pattern as that of L. laeta venom at 32–35 kDa, recognized by serum anti-LlPLD1. In this context, we can conclude that the venom of Sicarius thomisoides is similar to Loxosceles laeta in many aspects, and the dermonecrotic toxin present in their venom could cause severe harm to humans; thus, precautions are necessary to avoid exposure to their bite.

Taucare-Ríos, Andrés, Veloso, Claudio, Bustamante, Ramiro O. (2017): Microhabitat selection in the sand recluse spider (Sicarius thomisoides): the effect of rock size and temperature. Journal of Natural History 51 (37-38): 2199-2210, DOI: 10.1080/00222933.2017.1367046, URL: http://dx.doi.org/10.1080/00222933.2017.1367046

Se registra el primer caso de depredación intra-gremio de Sicarius thomisoides sobre dos arácnidos de ambientes desérticos de Chile: el escorpión Brachistosternus mattoni y el solífugo Pseudocleobis sp. Se describen las circunstancias de la interacción y se discute sobre la importancia del registro, ya que son artrópodos simpátricos pertenecientes al mismo gremio ecológico.

Taucare-Ríos, Andrés, Iuri, Hernán A. (2021): Primeros registros de depredación intra-gremio de Sicarius thomisoides Walckenaer, 1847 (Araneae: Sicariidae) sobre el escorpión Brachistosternus mattoni (Ojanguren-Affilastro, 2005) (Scorpiones: Bothriuridae) y el solífugo Pseudocleobis sp. (Solifugae: Ammotrechidae) en Chile. Revista Chilena de Entomología (Rev. Chil. Entomol.) 47 (2): 211-217, DOI: 10.35249/rche.47.2.21.06, URL: http://dx.doi.org/10.35249/rche.47.2.21.06

Berlandiella Mello-Leitão, 1929 is currently composed of six Neotropical species, of which Berlandiella querencia Lise & Silva, 2011 is known only from female specimens; the other species of the genus were described based on both males and females. In this paper, we describe and illustrate Berlandiella zabele sp. nov., based on a few individuals collected in Sete Cidades National Park, Piracuruca and Brasileira, state of Piauí, Brazil. We illustrate and describe the previously unknown male of B. querencia, based on a specimen collected from Reserva Mocambo, Belém, state of Pará, Brazil. The taxa described herein have scopula in the tarsi and metatarsi, and the males have a cymbial process, characters recorded for the first time for the genus. Additionally, we present an updated diagnosis for Berlandiella.

Tesis Entregada a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al grado de Doctor en Ciencias con mención en Ecología y Biología Evolutiva.<br>Las arañas son ectotermos estrictos y son importantes depredadores en muchos ecosistemas terrestres. El estudio de la biología térmica es particularmente relevante en las arañas en el que los límites térmicos influyen eventualmente sobre el fitness. El modelo de estudio corresponde a la especie Sicarius thomisoides, un arácnido ampliamente distribuido en ambientes desérticos y semidesérticos de Chile, viviendo en un gradiente térmico latitudinal considerable con altas (interior) y bajas fluctuaciones térmicas (costa). En esta tesis se propone que el nicho térmico puede ser considerado como un factor de orden distal que determina en las arañas efectos a nivel individual y a nivel poblacional, afectando así procesos de pequeña escala como la fisiología térmica y la selección de micro-hábitat y de gran escala como la distribución geográfica. El primer capítulo de esta tesis busca establecer los requerimientos térmicos (nicho térmico) de la especie, con el objetivo de aproximarse al nicho fundamental. Además, debido a que la temperatura cambia a lo largo de gradientes ambientales, se evaluará la posible variación geográfica del nicho térmico. En segunda instancia los siguientes dos capítulos buscan determinar la concordancia entre los requerimientos térmicos hallados en laboratorio (nicho fundamental) y el uso de los mismos en condiciones de campo (nicho realizado) a dos diferentes escalas: a micro escala, evaluando el efecto de la temperatura en la selección de micro-hábitat y a macro escala, combinando las curvas de desempeño térmico con la distribución potencial de la especie. Los resultados de esta tesis muestran una alta concordancia entre el nicho realizado y fundamental, al menos en lo que se refiere al nicho térmico, por lo que se puede señalar que gran parte de los requerimientos térmicos fisiológicos de la especie se pueden encontrar en condiciones de campo, donde la araña es capaz de seleccionar aquellos sitios que maximicen su desempeño y evitar sitios que sean térmicamente perjudiciales, tanto a micro escala como a macro escala geográfica.<br>Spiders are strict ectotherms and are important predators in many terrestrial ecosystems. The study of thermal biology is particularly relevant in spiders in which thermal limits eventually influence fitness. The study model corresponds to the species Sicarius thomisoides, an organism distributed in desert and semi-desert environments of Chile, which lives in a considerable latitudinal thermal gradient with high (interior) and low thermal fluctuations (coast). In this thesis, it is proposed that the thermal niche can be considered as a factor of distal order that determines in the spiders effects at an individual level and at a population level, affecting small scale processes such as thermal physiology and the selection of micro-habitat and large scale as the geographical distribution. The first chapter of this thesis seeks to establish the thermal requirements of the species, with the aim of approaching the fundamental niche. In addition, due to the temperature changes along the environmental gradients, the possible geographic variation of the thermal niche is evaluated. In second instance, the following titles capture the agreement between the thermal requirements found in the laboratory (fundamental niche) and the use of them in field conditions (niche) at two different scales: a micro scale, evaluating the effect of the temperature in the selection of micro-habitat and macro-scale, combining the thermal performance curves with the potential distribution of the species. The results of this test show a high concordance between the realized and fundamental niche, at least as regards the thermal niche, so it can be stated that the great part of the physiological thermal requirements of the species can be found in the field conditions, where the spider is able to select sites that maximize its performance and avoid sites that are thermally damaging, both a micro scale and a macro geographical scale.<br>CONICYT Beca de doctorado No. 21130014.<br>Enero 2022