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

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  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 (...

Possible estimate of litter size in palaeoburmesebuthid scorpions from Early Cretaceous Burmite (Chelicerata: Scorpiones)

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Possible estimate of litter size in palaeoburmesebuthid scorpions from Early Cretaceous Burmite (Chelicerata: Scorpiones)

Abstract 

In previous studies concerning litter size in extant buthoid species of scorpions it was suggested that a number of factors could directly be associated with litter size variation. Litter size should be directly proportional to the size of adult females but inversely proportional to the size of the embryos and pro-juveniles. The large body size of pro-juveniles at birth should be directly associated with a more complete embryonic development, leading to post-embryonic developments including smaller numbers of instars but with higher values ​​for the morphometric growths. For fossil scorpions and in particular those from Early Cretaceous nothing could be presumed until now. An original observation of pro-juvenile aggregation for Betaburmesebuthus suggests that for micro-buthoid fossil scorpions litter size was extremely reduced but composed of large embryos and pro-juveniles. 

Lourenço WR & Velten J., 2024. – Possible estimation of litter size in palaeoburmesebuthid scorpions from Early Cretaceous Burmite (Chelicerata: Scorpiones). Faunitaxys , 12(49): 1 – 4. 

https://hal.science/hal-04719088 - https://zoobank.org/5F279A52-DBD0-48CC-8BF4-F32BCF868CD6