Two new Brazilian species of Loxosceles Heinecken & Lowe, 1832 with remarks on amazonica and rufescens groups (Araneae, Sicariidae)

Abstract

The genus Loxosceles Heinecken & Lowe, 1832 has 91 representatives in the New World. Despite medical relevancy, the taxonomy of the genus is poorly understood. South American Loxosceles were divided into four groups of species: laeta, spadicea, gaucho and amazonica; this last one has a single species, Loxosceles amazonica Gertsch, 1967. More recently, the natural occurrence of L. amazonica in the New World has been questioned, due to the strong morphological resemblance and close phylogenetic relationship with Old World species, mainly with Loxosceles rufescens (Dufour, 1820). Herein, L. amazonica is rediagnosed and its morphological variation and natural distribution discussed. Two new species closely related to it from northeastern Brazil are also described, Loxosceles willianilsoni sp. n., from the state of Rio Grande do Norte, and Loxosceles muriciensis sp. n., from the state of Alagoas. The relationships of these new species with L. amazonica and L. rufescens are discussed.

On Chilean Loxosceles (Araneae: Sicariidae): first description of the males of L. surca and L. coquimbo, new records of L. laeta and three remarkable new species from coastal deserts

“…coquimbo Gertsch, 1967 are records from Gertsch (1967). female genital morphology is quite unmodified, and does not resemble the highly apomorphic female morphology of any of these groups (with sclerotized plates in the gaucho-group, and with several apical lobes in the the rufescens-group, see Fukushima et al 2017). Additionally, the keel in the male palp could be a shared feature between this species and the spadicea-group.…”

Alien spiders: First record of Loxosceles gaucho Gertsch, 1967 (Araneae: Sicariidae) in the Amazon region, Brazil

“…These two species can be distinguishable by the identification key below. Gertsch, 1967 ¹Rio de Janeiro and ¹São Paulo Loxosceles amazonica Gertsch, 1967 ¹³Amazonas, ²Pará, ²Tocantins, ²Bahia, ²Ceará, ²Maranhão, ²Paraiba, ²Pernambuco, ²Piaui, ⁴Rio Grande do Norte and ²Mato Grosso Loxosceles anomala (Mello-Leitão, 1917) ⁸Minas Gerais Loxosceles cardosoi Bertani, von Schimonsky & Gallão, 2018 ⁵Bahia Loxosceles carinhanha Bertani, von Schimonsky & Gallão, 2018 ⁵Bahia Loxosceles chapadensis Bertani, Fukushima & Nagahama, 2010 ⁵Bahia Loxosceles ericsoni Bertani, von Schimonsky & Gallão, 2018 ⁵Minas Gerais Loxosceles gaucho Gertsch, 1967 ¹São Paulo, ¹⁹Paraná, ¹Rio Grande do Sul and Amazonas* Loxosceles hirsuta Mello-Leitão, 1931 ⁶Paraná and ⁶Rio Grande do Sul Loxosceles immodesta (Mello-Leitão, 1917), ⁸São Paulo Loxosceles intermedia Mello-Leitão, 1934 ⁷São Paulo, ¹⁷Rio de Janeiro, ⁹Paraná and Distrito Federal Loxosceles karstica Bertani, von Schimonsky & Gallão, 2018 ⁵Bahia and ⁵Minas Gerais Loxosceles laeta (Nicolet, 1849) ¹Rio Grande do Sul, ¹Santa Catarina, ⁹Paraná, ¹São Paulo, ¹Minas Gerais and ¹⁰Rio de Janeiro Loxosceles muriciensis Fukushima ¹Gertsch, 1967;²Silveira, 2015;³Almeida et al, 2017;⁴Fukushima et al, 2017;⁵Bertani et al, 2018b;⁶Mello-Leitão, 1931;⁷Mello-Leitão, 1934;⁸Mello-Leitão, 1917;⁹Marques-da-Silva & Fischer, 2005;¹⁰Silveira, 2009;¹¹Gonçalves-de-Andrade et al, 2012;¹²Martins et al, 2002;¹³Souza & Ferreira, 2018. Almeida, M.Q.…”

Envenomation by an arachnid (Latrodectus or Steatoda): Case report involving a woman and her female dog

“…(23) On the other hand, analgesic treatment seems to be sufficient for Steatoda, although Latrodectus antivenom could be effective in some cases. (24) For comparison purposes, adequate treatment in cases involving another relatively common spider in the region (25), Loxosceles. spp., contemplates: rest, ice, compression and elevation (RICE) (26-28), although wound care and surgical intervention may be needed in severe cases (this is recommended from 6 to 8 weeks after the bite to allow tissue healing).…”