Alejandro Valdez-Mondragón

Four new species of the genus Pseudocellus (Arachnida: Ricinulei: Ricinoididae) from Mexico

Abstract Four new species of ricinuleids are described: Pseudocellus chankin from caves and surface collections in southern Mexico (Chiapas & Tabasco) and Guatemala (Petén); Pseudocellus jarocho from a single surface collection in Veracruz, México; Pseudocellus oztotl, a troglobitic and troglomorphic species from Cueva de Las Tres Quimeras in the Sierra Negra, Puebla, Mexico; and Pseudocellus platnicki, also troglobitic and troglomorphic, known from a single cave in Coahuila, Mexico. The number of known species in the genus increases to 24, and Mexican species to 14. An identification key for adult males of the species found in Mexico and southern USA is provided.

Morphological phylogenetic analysis of the spider genus Physocyclus (Araneae: Pholcidae)

Abstract With 30 species and a natural distribution in North America, 28 confined to Mexico, Physocyclus Simon 1893 is the most diverse genus within the pholcid spider subfamily Arteminae. This paper provides the first phylogenetic test of the genuss monophyly through a cladistic analysis of 54 morphological characters using equal and implied weighting. The equally weighted analysis found 12 most parsimonious trees, whereas the analysis with implied weights varying the concavity values (K  =  6–10) found five or six most parsimonious trees. The monophyly of the genus Physocyclus is supported by three synaphomorphies: 1) the paired ventral apophysis on the anterior part of the epigynum; 2) the lateral constraints in the middle part of the epigynum; and 3) the arc of the uterus, with a single sclerotized projection on the anterior part. The genus Physocyclus contains two clades treated as species groups: the globosus group, with 11 species, and the dugesi group with 19 species. The species relationships within the globosus group were better resolved than those in the dugesi group. The globosus group has a biogeographical distribution pattern in the Mesoamerican and Mexican Mountain biotic components, whereas the dugesi group has a distribution pattern in the Mesoamerican and Continental Nearctic biotic components. Given the complex biogeography in Mexico, apparently a large-scale vicariant event separated the two major clades within the genus Physocyclus.

A new troglobitic species of the spider genus Tengella Dahl (Araneae, Tengellidae) from Chiapas, Mexico

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.

A reanalysis of the morphological phylogeny of the spider genus Physocyclus Simon (Araneae: Pholcidae) with the description of a new species and description of the female of Physocyclus paredesi Valdez-Mondragón from Mexico

A new species of spider from Michoacán, Physocyclus peribanensis sp. nov. is described. This description is based on a male holotype and one female paratype. Also, the first description of the female of Physocyclus paredesi Valdez-Mondragón from Oaxaca, Mexico is provided, as well as the redescription of the male. This paper provides a cladistic reanalysis of the spider genus Physocyclus Simon, corroborating the monophyly of the genus with morphological data. The phylogenetic reanalysis was done with 54 morphological characters (44 binary and 10 multistate) using equal and implied weighting approach. The equal weighting analysis found two most parsimonious trees, whereas the analysis with implied weighting found just one most parsimonious trees with the concavity values (K= 5-10). The genus Physocyclus is composed by two clades or species groups: the globosus and the dugesi groups. Physocyclus peribanensis sp. nov. belongs to the dugesi group composed of 21 species, and P. paredesi to the globosus group composed of 11 species. With the new species described here, the number of known species of the genus Physocyclus increases to 32 species. The globosus group has a biogeographical distribution pattern in the Mesoamerican and Mexican Mountain biotic components, whereas the dugesi group has a biogeographical distribution in the Mesoamerican and Continental Nearctic biotic components.

Microhabitat change drives diversification in pholcid spiders

BackgroundMicrohabitat changes are thought to be among the main drivers of diversification. However, this conclusion is mostly based on studies on vertebrates. Here, we investigate the influence of microhabitat on diversification rates in pholcid spiders (Araneae, Pholcidae). Diversification analyses were conducted in the framework of the largest molecular phylogeny of pholcid spiders to date based on three nuclear and three mitochondrial loci from 600 species representing more than 85% of the currently described pholcid genera.ResultsAssessments of ancestral microhabitat revealed frequent evolutionary change. In particular, within the largest subfamily Pholcinae, numerous changes from near-ground habitats towards leaves and back were found. In general, taxa occupying leaves and large sheltered spaces had higher diversification rates than ground-dwelling taxa. Shifts in speciation rate were found in leaf- and space-dwelling taxa.ConclusionsOur analyses result in one of the most comprehensive phylogenies available for a major spider family and provide a framework for any subsequent studies of pholcid spider biology. Diversification analyses strongly suggest that microhabitat is an important factor influencing diversification patterns in pholcid spiders.

Two new species of the spider genus Ochyrocera (Araneae, Ochyroceratidae) from Mexico.

Abstract Two new species of the spider genus Ochyrocera Simon 1891 are described from Mexico. Ochyrocera juquila new species was collected under moist rotten logs and hollow trunks on a thick bed of pine needles in oak-pine forests located in a mountain range south of the city of Oaxaca at 1400–2700 m elev. Ochyrocera juquila resembles O. quinquevittata Simon 1891 from the Island of St. Vincent, in the angular shape of the embolus, which in the new species is V-shaped and in O. quinquevittata is L-shaped. Ochyrocera chiapas new species, was collected under rotten trunks and hollow trunks in abundant leaf litter in the tropical, humid Lacandona rainforest region located in eastern Chiapas, near the border with Guatemala. The species occurs at 160–260 m elev. Ochyrocera chiapas resembles O. arietina Simon, 1891 from the island of St. Vincent, in the similar shape of the embolus and distal apophysis of the cymbium, but in O. chiapas the embolus is more strongly curved and directed toward the distal part of the tibiae forming a “D”; in O. arietina the embolus is not as strongly curved as in O. chiapas. In both species, males and females were collected near each other; the females carried their egg sacs with their chelicerae. A key to the four known Mexican species is provided.

New morphological data for the order Ricinulei with the description of two new species of Pseudocellus (Arachnida: Ricinulei: Ricinoididae) from Mexico

Abstract Two new species of ricinuleids of the genus Pseudocellus Platnick, 1980 are described based on adult males and females from Mexico: Pseudocellus quetzalcoatl sp. nov. and Pseudocellus olmeca sp. nov. from the same type locality in the state of Veracruz. The two new species represent the first record of two sympatric epigean species of ricinuleids for North America. The total number of described species of Pseudocellus from Mexico increases to 18, holding first place in terms of number of known ricinuleid species worldwide. With the two new species described herein, Veracruz, with four species, is the second state of Mexico with higher diversity after Chiapas, which has five recorded species. We describe for the first time, for any ricinuleids, pores on the membrane below the spermathecae, revealed using a staining technique. The function of these pores is unknown, although it is possible that these could be secretion glands for some kind of substance during the reproductive process. A taxonomic key for identification of males of species from Mexico and the southern United States is provided.

On the poorly known haplogynae spiders of the genus Ochyrocera Simon (Araneae, Ochyroceratidae) from Mexico: description of two new species with an updated identification key for Mexican species

Two new species of the spider genus Ochyrocera Simon 1891 are described from Mexico. Ochyrocera jarocha new species was collected under rotten trunks and hollow trunks in a tropical rainforest, in San Martin Volcano, Veracruz, Mexico. Ochyrocera pojoj new species was collected in a mixed forest, under rotten trunks, in La Trinitaria, Chiapas, Mexico, which represents the third species described from the state of Chiapas. With the description of the two new species herein, six species of Ochyrocera are recorded from Mexico. An updated taxonomic identification key and a distribution map to the Mexican species are provided.

Spiders of the Orbiculariae clade (Araneae: Araneomorphae) from Calakmul municipality, Campeche, Mexico

A study was conducted to determine the biological richness of orb-weaver spiders from Calakmul municipality, Campeche, Mexico. Material deposited in the Coleccion Nacional de Aracnidos, Instituto de Biologia, 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.

A remarkable new species of the magnus species-group of Cryptocellus (Arachnida, Ricinulei) from Ecuador, with observations on the taxonomy of the New World genera

A new ricinuleid species, Cryptocellus chimaera sp. nov., is described based on a male specimen from Northwest Ecuador (Esmeraldas, Reserva Ecológica Mache-Chindul, Estación Biológica Bilsa). This species is unique among all Cryptocellus in having very large longitudinal carapacial translucent areas together with a markedly incrassate femur of leg II. Representing only the second species of the order described from Ecuador, C. chimaera sp. nov. is assigned to the magnus species-group of Cryptocellus Westwood, 1874. Cryptocellus chimaera sp. nov. is remarkable, for its morphology resembles that of Cryptocellus magnus Ewing, 1929, especially with regard to the male copulatory apparatus, although both resemble Pseudocellus Platnick, 1980, due to the presence of diffuse longitudinal carapacial translucent areas. Along with the new species description, a comparative diagnosis and supplementary images are provided for C. magnus. Based on direct observations of some species belonging to the five species-groups of Cryptocellus, we discuss on the occurrence of different morphologies of carapacial translucent areas within the genus. We deem it important to continue the survey of morphological characters, especially within Cryptocellus, in order to increase our understanding of the species-groups and to unravel their relationships.