RESUMO
A new species of the spider genus Loxosceles Heineken & Lowe, 1832, Loxosceles tenochtitlan Valdez-Mondragón & Navarro-Rodríguez, sp. nov., is described based on adult male and female specimens from the states of Mexico City, Estado de Mexico and Tlaxcala. Integrative taxonomy including traditional morphology, geometric and lineal morphology, and molecules (DNA barcodes of cytochrome c oxidase subunit 1 (CO1) and internal transcribed spacer 2 (ITS2)), were used as evidence to delimit the new species. Four methods were used for molecular analyses and species delimitation: 1) corrected p-distances under neighbor joining (NJ), 2) automatic barcode gap discovery (ABGD), 3) general mixed yule coalescent model (GMYC), and 4) poisson tree processes (bPTP). All molecular methods, traditional, geometric and lineal morphology were consistent in delimiting and recognizing the new species. Loxosceles tenochtitlan sp. nov. is closely related to L. misteca based on molecular data. Although both species are morphologically similar, the average p-distance from CO1 data was 13.8% and 4.2% for ITS2 data. The molecular species delimitation methods recovered well-supported monophyletic clusters for samples of L. tenochtitlan sp. nov. from Mexico City + Tlaxcala and for samples of L. misteca from Guerrero. Loxosceles tenochtitlan sp. nov. is considered a unique species for three reasons: (1) it can be distinguished by morphological characters (genitalic and somatic); (2) the four different molecular species delimitation methods were congruent to separate both species; and (3) there is variation in leg I length of males between both species, with the males of L. misteca having longer legs than males of L. tenochtitlan sp. nov., also morphometrically, the shape of tibiae of the palp between males of both species is different.
RESUMO
A new species of the spider genus Loxosceles Heineken & Lowe, 1832, Loxoscelesmalintzi sp. n., is described from the states of Puebla, Morelos and Guerrero, in the central region of Mexico. The description is based on adult males and females with morphological and ultra-morphological images. Updated distribution maps are provided for the 39 species recorded from the Mexican territory (including the new species). The states with the greatest diversity are Baja California Sur, Baja California and Sonora, with five species each. A total of 441 records for the 39 species, based on arachnological collections, data bases and literature, were used to update the distribution maps. Loxoscelesboneti Gertsch, 1958 is the species with the highest number of records in Mexico, with a total of 58 records from different localities. The states with the most records so far are Guerrero, with 55 records, Morelos, with 35 records, and Baja California Sur, with 30 records. Loxoscelesrufescens (Dufour, 1820), an introduced species, is recorded for the second time in Mexico, from the state of Chihuahua, being the first well-documented record for the country. Mexico has the greatest diversity of species of Loxosceles worldwide, with 39 (two introduced species) of the 134 described species. Additionally, biogeographical comments for the species from Mexico are provided.
