Integrative taxonomy is relevant for the discovery and delimitation of cryptic species by incorporating different sources of evidence to construct rigorous species hypotheses. The genus Davus was recently revised and it was found that Davus pentaloris presents high morphological variation across its widespread distribution. However, tarantulas usually present low dispersal capabilities that occasionally result in local endemism. In order to evaluate species boundaries within this taxon, we examine the morphological variation and, additionally, employ four strategies based on mtDNA data (COI): two distance-based [automatic barcode gap discovery (ABGD) and Neighbor-Joining (NJ)] and two tree-based methods [general mixed Yule coalescent (GMYC) and Bayesian Poisson tree process (bPTP)]. Available morphological evidence recovers 13 putative morphospecies, but the different methods based on molecular data recover a variable number of candidate species (16–18). Based on the congruence across all analyses and the available morphological data, we recognize 13 clearly diagnosable species, 12 of them new to science. We conclude that the underestimation of the diversity in D. pentaloris was mainly caused by deficient practices in taxonomy, rather than by the presence of cryptic diversity. Although COI is a functional barcoding marker and it gives reliable results in our study, we recommend combining multiple sources of evidence and strategies to construct better species delimitation hypotheses.

A study was conducted to determine the biological richness of orb-weaver spiders from Calakmul municipality, Campeche, Mexico. Material deposited in the Colección Nacional de Arácnidos, Instituto de Biología, UNAM was revised. In addition, 16 collecting events were made in 14 localities of Calakmul municipality during this study. The collections were made using beating sheets and manual technique. A total of 1,151 specimens belonging to 8 families, 56 genera and 100 species were reviewed and identified. Two new species and 3 considered possibly new were found, which cannot be confirmed until specimens of both sexes are collected. According to previous studies and this work, 10 families, 65 genera and 119 species of spiders of orb-weaver spiders are present in Calakmul municipality, of which 4 families, 32 genera and 74 species are recorded for the first time. Furthermore, this work adds 3 genera and 10 species to the known diversity for the country, making a total of 14 families, 139 genera and 685 species of orb-weaver spiders recorded for Mexico. ResumenSe realizó un estudio con el objetivo de conocer la riqueza biológica de arañas tejedoras de redes orbiculares del municipio de Calakmul, Campeche, México. Se revisó material depositado en la Colección Nacional de Arácnidos, Instituto de Biología, UNAM. Además, se realizaron 16 muestreos en 14 localidades del municipio Calakmul para la recolecta de ejemplares. Las recolectas se realizaron por medio del uso de redes de golpeo y técnica manual. Se recolectaron, revisaron e identificaron 1,151 ejemplares pertenecientes a 8 familias, 56 géneros y 100 especies. Dos especies nuevas y otras 3 se consideran posiblemente nuevas, lo que podrá confirmarse hasta obtener ejemplares de ambos sexos. De acuerdo con estudios previos y este trabajo, en el municipio Calakmul se encuentran presentes 10 familias, 65 géneros y 119 especies de arañas tejedoras, de las cuales 4 familias, 32 géneros y 74 especies se registran por primera vez. Además, este trabajo adiciona 3 géneros y 10 especies a la diversidad conocida para el país, siendo un total de 14 familias, 139 géneros y 685 especies de arañas tejedoras de redes orbiculares registradas para México.

Since its original description, the theraphosid spider genus Crassicrus Reichling & West, 1996 has not been revised and no new species have been described. While reviewing material deposited in the Mexican National Collection of Arachnids (National Autonomous University of Mexico, Mexico City) and the American Museum of Natural History (New York, USA), we encountered specimens corresponding to four new species of Crassicrus from Mexico. In this revision, we include a redescription of the genus and its type species, C. lamanai Reichling & West, 1996, and describe four new species: C. bidxigui, C. tochtli, C. cocona, and C. yumkimil. Species habitat data are provided, as well as identification keys for males and females. In addition, new keels on the male embolus were identified and are described. In the Theraphosinae, the presence of one retrolateral keel has been reported, but in Crassicrus, there are two or three retrolateral keels, and a new taxonomical nomenclature for these keels is proposed. The genus Crassicrus is recorded from Mexico for the first time, increasing the number of known theraphine genera in the country to 16.

A new species of troglobitic spider of the genus Tengella Dahl is described from Mexico: Tengella kalebi new species, from a limestone cave in Chiapas, Mexico. The species is described on the basis of adult male and females. This is the fifth species described for the genus Tengella, the third species described from Mexico, the first species that has notable troglomorphic modifications, and the first ecribellate Tengella species.