A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala

Posted by
  A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala Abstract  A new species of the spider genus Euagrus Ausserer, 1875 from temperate pine-oak forests in the states of Tlaxcala and Hidalgo, Mexico is described: E. pulque sp. nov. The description of the new species is based on male and female adult specimens. Additionally, Euagrus gus Coyle, 1988 is recorded for the very first time in the state of Tlaxcala. These species have sympatric distributions in La Malinche National Park, Tlaxcala. With this description, the diversity of the genus increases to 23 species, with Mexico harboring the highest diversity with 17 described species.  Valdez-Mondragón, A., Salinas-Velasco, H. V. & Bueno-Villegas, J. (2026). A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala. Zootaxa 5810 (...

First report of arm-span competition in buthid scorpions: male-male contest in Tityus cf. rosenbergi Pocock, 1898

Posted by

 


First report of arm-span competition in buthid scorpions: male-male contest in Tityus cf. rosenbergi Pocock, 1898

Abstract

Although courtship and mating behaviors have been described for nearly all scorpion lineages, intrasexual interactions in scorpions remain understudied. Recently, a novel ritualized behavioral unit, termed “arm-span competition,” in which individuals face off and extend their pedipalps laterally, was described from analyses of male-male contests in several scorpionid species. Here, we present the first documented observation of arm-span competition in a buthid scorpion, Tityus cf. rosenbergi Pocock, 1898. Interestingly, both T. cf. rosenbergi and most scorpionid species known to engage in arm-span competition exhibit a similar sexual dimorphism: males have markedly longer and more slender pedipalps than females. We suggest that the elongated pedipalps in males of these species might be the result of selective pressure related to ritualized arm-span competition. We also highlight the potential for citizen science to contribute rare observations to scientific literature.

Aunque se han descrito comportamientos de apareamiento para casi todos los linajes de escorpiones, las interacciones intrasexuales siguen poco estudiadas. Recientemente, a partir del análisis de luchas macho-macho en algunos escorpiónidos, se describió una nueva unidad de comportamiento ritualizado denominada “competencia por extensión de pedipalpos” en que los individuos se enfrentan extendiendo sus pedipalpos lateralmente. En este trabajo, presentamos la primera observación documentada de este comportamiento en un bútido, Tityus cf. rosenbergi Pocock, 1898. Tanto T. cf. rosenbergi como la mayoría de las especies de escorpionidos en que se describió este comportamiento, exhiben un dimorfismo sexual similar: los machos tienen pedipalpos notablemente más elongados y delgados que las hembras. Con esta observación, sugerimos que los pedipalpos de los machos en estas especies sean el resultado de la presión selectiva relacionada con la competencia ritualizada por extensión de pedipalpos. Además, enfatizamos el potencial de la ciencia ciudadana para contribuir con observaciones raras a la literatura científica.

Jules Thornton Wyman, Julien Wright-Ueda, Quinn Agnew, Ismael Castellano, Yuri Simone "First report of arm-span competition in buthid scorpions: male-male contest in Tityus cf. rosenbergi Pocock, 1898," The Journal of Arachnology, 52(3), 210-213, (5 January 2025) https://doi.org/10.1636/JoA-S-23-009