Two new genera of epigean harvestmen (Opiliones, Stygnopsidae) from Oaxaca, Mexico, with an identification key for the stygnopsine genera.

Two new genera, Ampliphallus gen. nov. and Guelaguetzia gen. nov., are described from material collected in the state of Oaxaca, Mexico. The genus Ampliphallus gen. nov. is monotypic and contains the species A. chimalapaensis sp. nov., from the tropical rain forest of Santa María Chimalapa, Oaxaca. The genus Guelaguetzia gen. nov. is composed of two species: G. cuicateca sp. nov. (type species) and G. serrana sp. nov., from pine forests in northern Oaxaca. These genera can be recognized from each other mainly by the armature of leg IV and by the male genitalia; both are also compared with the remaining members of the Stygnopsinae. An identification key for all genera of the subfamily is provided.

Conspectus Genericus Scorpionorum 1758-1985 (Arachnida: Scorpiones) updated through 2018.

Genus and subgenus names introduced for all Recent and fossil scorpions from 1758-2018, are listed. The treatment follows the Conspectus of Francke (1985) and Dupré (2007) with considerable additional information accumulated during intensive scorpiological research of 2006-2018. The list also includes all available generic and subgeneric synonyms, incorrect spellings and unavailable emendations. For Recent taxa the new totals are 19 families compared to only nine in the first Conspectus, 220 genera with an increase of almost 100 from the first version, and 23 subgenera; for fossil taxa there are 43 families and 80 genera, 12 of which are incertae sedis. The type species of all accepted genus-group names are given.

Taxonomic revision of Anicius Chamberlin, 1925 (Araneae: Salticidae), with five new species of jumping spiders from Mexico.

Anicius Chamberlin, 1925 is a monotypic genus and only the male of A. dolius Chamberlin, 1925 has been described. Herein the genus is revised and the female of the type species is described for the first time; new distribution records are also provided for this species. Five new species from Mexico are described based on males and females: Anicius chiapanecus sp. nov., Anicius cielito sp. nov., Anicius faunus sp. nov., Anicius grisae sp. nov., and Anicius maddisoni sp. nov. A key for identification of males and females is given, as well as a map with distribution records of the six species.

A new species of the genus Centruroides Marx (Scorpiones, Buthidae) from western Michoacán State, México using molecular and morphological evidence.

A new species of scorpion belonging to the genus Centruroides Marx, 1890 is described from the Coalcomán mountain range, western Michoacán State, Mexico. Its general aspect resembles Centruroidesruana Quijano-Ravell & Ponce-Saavedra, 2016, and C.infamatus (C. L. Koch, 1844), but it is a smaller species having lower pectinal tooth counts; also, males of C.ruana have the pedipalp chelae slightly thicker, whereas C.infamatus has a subaculear tubercle nearer to the base of the aculeus. Another species with similar aspect is Centruroidesornatus Pocock, 1902; however, a preliminary molecular analysis of the mitochondrial gene mRNA 16S showed genetic divergence (measured as p-distance) near to 10% between these species, and lower differences between the new species with respect to C.infamatus (4.63%) and C.ruana (5.07%). The molecular evidence together with the morphological characters (integrative taxonomy) are sufficient for recognizing the Coalcomán population as a separate and valid species.

A new Sky Island species of Vaejovis C. L. Koch, 1836 from Sonora, Mexico (Scorpiones, Vaejovidae).

Vaejovis islaserranosp. n. is described from the Sierras Elenita and La Mariquita, Municipio de Cananea, Sonora, Mexico. This species belongs to the "vorhiesi" group of the genus Vaejovis and inhabits pine-oak forests in northern Mexico. This species is compared to its most similar species. This new species presents an interesting morphological difference from the rest of the species in the species-group: the absence of a subaculear tubercle or spine.

ResumenSe describe Vaejovis islaserranosp. n. de las Sierras Elenita y La Mariquita, en el Municipio de Cananea, Sonora, México. Esta especie pertenece al grupo "vorhiesi" dentro del género Vaejovis y que habita en los bosques de pino y encino del norte de México. Se le compara con las especies más similares morfológicamente. Esta nueva especie presenta una característica morfológica interesante para las especies del grupo: la ausencia de un tubérculo o espina subaculear.

A tangle of forms and phylogeny: Extensive morphological homoplasy and molecular clock heterogeneity in Bonnetina and related tarantulas.

Tarantula spider systematics has long been considered problematic. Species diagnosis and phylogenetic hypotheses have historically relied on morphological features, which are known to be relatively conserved and/or highly homoplastic across the family. Morphology-based attempts to clarify the phylogeny of the highly diverse New World Theraphosinae, have only been moderately successful, and the time-frame of tarantulas' evolution is nearly terra incognita. Here we present a molecular phylogenetic analysis of the Theraphosinae genus Bonnetina and related lineages, employing one mitochondrial (COI) and five nuclear (ITS1, EF1G, MID1IP1, MRPL44, and I3568) loci. We also perform ancestral state reconstruction of a newly formulated morphological data matrix. Our analysis includes 47 species placed in 17 genera and other undetermined lineages. We obtained well resolved and supported topologies. COI and EF1G substitution rates were much lower than the values generally accepted for mygalomorph evolution, with substantial rate heterogeneity among lineages. The origin of Theraphosinae was dated during the Late Cretaceous, followed by rapid diversification into the three recently proposed Theraphosinae tribes. North and Central American Hapalopini (including Bonnetina) form a monophyletic group that likely originated during the Oligocene to a dispersing ancestor from the then isolated South America. A clade that includes all but one Bonnetina species is estimated to have originated in the early Miocene and is the sister group of two morphologically divergent undescribed species. Morphological homoplasy is extensive across the tree. The two features that diagnose Bonnetina are homoplastic, but in combination still define the genus. Finally, we establish three groups of species within Bonnetina. Our results challenge the reliability of morphological characters for phylogenetic reconstruction in Theraphosinae, and indicate caution when interpreting Theraphosidae supra-specific classification in absence of a solid phylogenetic framework. They also question the dependability of universal substitution rates of COI and EF1G to calibrate phylogenetic analyses across Mygalomorphae.

Five new species of Stenochrus (Schizomida: Hubbardiidae) from Oaxaca, Mexico.

The North American genus Stenochrus is represented by 22 species distributed mainly in Mexico, Central America and the U.S.A.; the genus was erected originally to place the species Stenochrus portoricensis and was characterized by the presence of lateral lobes reduced on female spermathecae, male flagellum without important dorsal relief, pedipalps without distinctive armature and without posterodorsal process on segment XII. Here we describe five new species from the Mexican state of Oaxaca; we discuss the presence of dimorphic males in the genus. With this contribution the genus Stenochrus reaches 27 species, becoming the second most diverse genus of schizomids in the New World.

Five new cave-dwelling species of Hemirrhagus Simon 1903 (Araneae, Theraphosidae, Theraphosinae), with notes on the generic distribution and novel morphological features.

The suborder Mygalomorphae is generally poorly represented in the cave faunas of the world. The genus Hemirrhagus is endemic to Mexico and has 22 described species. It is the only one with epigean, troglophile and troglobitic species. Lack of urticating setae, loss of eye pigmentation and ocular reduction are interpreted as evolutionary reversals related to their troglobitic habits. From five troglobitic species in the genus, only the male of Hemirrhagus stygius is known. Five new troglobitic species are described with both sexes: Hemirrhagus akheronteus sp. nov., Hemirrhagus billsteelei sp. nov., Hemirrhaugus diablo sp. nov., Hemirrhagus kalebi sp. nov. and Hemirrhagus sprousei sp. nov. The female of Hemirrhagus chilango is described for the first time. Hemirrhagus akheronteus sp. nov. has a group of spinose setae on the opisthosoma; this setal modification was never reported in any other theraphosid spiders. Females of Hemirrhagus kalebi sp. nov. and Hemirrhagus sprousei sp. nov. lay fixed hammock egg sacs, which is an unusual behavior among species in Theraphosinae. Two stridulating setae previously reported only in epigean species are present on some of the new troglobites.

Two DNA barcodes and morphology for multi-method species delimitation in Bonnetina tarantulas (Araneae: Theraphosidae).

Determining species boundaries is a central debate in biology. Several recently developed molecular delimitation methods have highlighted extensive inconsistency in classical morphological taxonomy. However, choosing between them is contentious. Molecular studies on theraphosid spiders have found considerable cryptic diversity and many species redundantly described. Most of these studies have relied only on COI, a mitochondrial marker that has proven its efficacy in animal studies, but which also might lead to an over-estimation of diversity. Here we present an integrative approach to species delimitation in Bonnetina, a poorly known group of tarantulas endemic to Mexico. We employed morphological evidence, as well as different setups with distance-based (Hard-Gap barcoding and ABGD) and tree-based (GMYC, PTP and BPP) molecular barcoding approaches, using one mitochondrial (COI) and one nuclear (ITS1) rapidly evolving loci. BPP is also used as a multi-locus method. We also explored the influence of ambiguous alignment choice and of coding gaps as characters in phylogenetic inference and in species delimitation with that marker. Different delimitation methods with COI gave moderately variable results and this gene exhibited a universal barcode gap. The ITS1 gene tree was well supported and robust to alignment choice; with this locus, coding gaps improved branch support and species delimitation with PTP. No universal barcode gap was found with ITS1, and single locus delimitations returned disparate results. However, this locus helped to highlight cases of under- and overestimations by COI. BPP gave solutions with many lineages, in single locus and combined analyses, especially with the recently implemented unguided methodology. We recognize 12 robustly supported species in our data set, of which seven remain undescribed, and three are morphologically cryptic. For COI Bonnetina species identification, we propose intra- and inter-specific thresholds of 2% and 6% sequence divergence, respectively. We conclude that morphological signal for species delimitation in Bonnetina is higher than for other studied tarantulas, but it fails to recognize several lineages in the genus. COI is a functional barcoding marker, and the most reliable source of evidence that we used, but it may also lead to inaccurate delimitations. ITS1 is a highly informative locus for species delimitation and species-level phylogeny, but it performs poorly as a barcoding marker. Due to variability between delimitation methods, we suggest combining evidence from multiple approaches to get better-supported results.

Scorpions from Mexico: From Species Diversity to Venom Complexity.

Scorpions are among the oldest terrestrial arthropods, which are distributed worldwide, except for Antarctica and some Pacific islands. Scorpion envenomation represents a public health problem in several parts of the world. Mexico harbors the highest diversity of scorpions in the world, including some of the world's medically important scorpion species. The systematics and diversity of Mexican scorpion fauna has not been revised in the past decade; and due to recent and exhaustive collection efforts as part of different ongoing major revisionary systematic projects, our understanding of this diversity has changed compared with previous assessments. Given the presence of several medically important scorpion species, the study of their venom in the country is also important. In the present contribution, the diversity of scorpion species in Mexico is revised and updated based on several new systematic contributions; 281 different species are recorded. Commentaries on recent venomic, ecological and behavioral studies of Mexican scorpions are also provided. A list containing the most important peptides identified from 16 different species is included. A graphical representation of the different types of components found in these venoms is also revised. A map with hotspots showing the current knowledge on scorpion distribution and areas explored in Mexico is also provided.

New Fossil Scorpion from the Chiapas Amber Lagerstätte.

A new species of scorpion is described based on a rare entire adult male preserved in a cloudy amber from Miocene rocks in the Chiapas Highlands, south of Mexico. The amber-bearing beds in Chiapas constitute a Conservation Lagerstätte with outstanding organic preservation inside plant resin. The new species is diagnosed as having putative characters that largely correspond with the genus Tityus Koch, 1836 (Scorpiones, Buthidae). Accordingly, it is now referred to as Tityus apozonalli sp. nov. Its previously unclear phylogenetic relationship among fossil taxa of the family Buthidae from both Dominican and Mexican amber is also examined herein. Preliminarily results indicate a basal condition of T. apozonalli regarding to Tityus geratus Santiago-Blay and Poinar, 1988, Tityus (Brazilotityus) hartkorni Lourenço, 2009, and Tityus azari Lourenço, 2013 from Dominican amber, as was Tityus (Brazilotityus) knodeli Lourenço, 2014 from Mexican amber. Its close relationships with extant Neotropic Tityus-like subclades such as 'Tityus clathratus' and the subgenus Tityus (Archaeotityus) are also discussed. This new taxon adds to the knowledge of New World scorpions from the Miocene that are rarely found trapped in amber.

A new species of the "mexicanus" group of the genus Vaejovis C. L. Koch, 1836 from the Mexican state of Aguascalientes (Scorpiones: Vaejovidae).

A new species of Vaejovis is described from the Mexican state of Aguascalientes. It is assigned to the "mexicanus" group and compared with similar species from Jalisco, Guanajuato, and San Luis Potosí. A map with their known distributions is provided.

The first troglomorphic species of the genus Phrynus Lamarck, 1801 (Amblypygi: Phrynidae) from Mexico.

A new troglomorphic species, Phrynus perrii sp. nov., is described from two adult females from Cueva del Naranjo, Municipio Cintalapa, Chiapas, Mexico. This is the first continental record of a troglomorphic Phrynus species, and the second troglomorphic species of the genus. With the description of this species, in Mexico there are ten extant species, plus one fossil of the genus Phrynus, and it is the seventh species of troglobitic whip spiders from Mexico, making it the country with the highest richness of amblypygids species worldwide.

Taxonomic revision of the genus Mayazomus Reddell & Cokendolpher, 1995 (Schizomida: Hubbardiidae), with description of five new species from Chiapas, Mexico.

The genus Mayazomus currently contains two species from southeastern Mexico. It was originally characterized by a strongly elongated pedipalp trochanter, united in its entire width to the femur; the patella strongly curved; the tibia with a large mesal apophysis opposable to tarsus; the spermathecae with two pairs of thin lobes subequal in length; and the presence of four or more setae on tergite II. In the present contribution, the species of the genus Mayazomus are revised and new diagnostic characters for the genus are proposed, including the correction that the female flagellum bears three rather than two annuli. The two known species are redescribed based on examination of the holotypes, plus newly acquired material representing both sexes (female previously unknown for one). Five new species from the Mexican state of Chiapas are described, based on adult males and females: Mayazomus tzotzil new species, Mayazomus aluxe new species, Mayazomus kaamuul new species, Mayazomus yaax new species, and Mayazomus loobil new species. Dimorphism in male pedipalps is reported for the first time for the genus. A dichotomous key is provided for identification of the seven species in the genus; and a distribution map is included. 

First record of the mygalomorph spider family Paratropididae (Arachnida, Araneae) in North America with the description of a new species of Paratropis Simon from Mexico, and with new ultramorphological data for the family.

A new species of the genus Paratropis is described from North America: Paratropis tuxtlensis sp. n., from a tropical rainforest in Veracruz, Mexico. This is the fifth Paratropis and the tenth paratropidid species described and the first North American record of this Neotropical family. The species is described based on adult males and females, and juveniles. The juveniles show ontogenetic variation in the number of cuspules on the labium and endites, and in the number and position of leg trichobothria. This is the second Paratropis species, and the third paratropidid known from both sexes. The scanning electron photographs (SEM) reveal new morphological data and contribute to the knowledge of the family.

Two new species of the genus Paramitraceras Pickard-Cambridge, 1905 (Opiliones: Laniatores: Stygnopsidae) from Chiapas, Mexico.

Parainitraceras pickardcanibridgei sp. nov. and Paramitraceras tzotzil sp. nov. from Chiapas, Mexico are described based on specimens previously determined as Paramitraceras granulatum Pickard-Cambridge, 1905 by Goodnight and Goodnight. The male genitalia of the new species and P. granulatum are illustrated with scanning electronic micrographs (SEMs) or drawings derived from them. The importance of the ocular tubercle, cheliceral dentition and sexual dimorphism, pedipalpal armature and male genitalia as taxonomic characters within the genus is discussed as well as differences and similarities between Paramitraceras Pickard-Cambridge, 1905 and its most similar genus, Sbordonia Silhavý, 1977.

Two new species of ricinuleids of the genus Pseudocellus (Arachnida: Ricinulei: Ricinoididae) from southern Mexico.

Two new species of ricinuleids of the genus Pseudocellus are described from Mexico: Pseudocellus cruzlopezi sp. nov. from Oaxaca, and Pseudocellus monjarazi sp. nov. from Chiapas. Both species are described from adult males and females. The first species is epigean and edaphomorphic, whereas the second is cavernicolous and troglomorphic. The number of known species of the genus Pseudocellus increases to 25, and Mexican species to 16, indicating that Mexico has the highest diversity of ricinuleids in the world. An updated identification key to adult males of the 16 described species found in Mexico and southern USA is provided.

Coadaptación entre los ácaros (Arachnida: Klinckowstroemiidae) y coleópteros Passalidae (Insecta: Coleoptera) / Co-adaptation between mites (Arachnida: Klinckowstroemiidae) and Passalidae beteles (Insecta: Coleoptera)

Co-adaptation between mites (Arachnida: Klinckowstroemiidae) and Passalidae beteles (Insecta: Coleoptera). Mites of the family Klinckowstroemiidae establish an association with beetles of the family Passalidae known as phoresy. In order to obtain information about this association, we analyzed the relationship between mites of the family Klinckowstroemiidae and beetles of the family Passalidae, as adult mites have been exclusively collected from host beetles. We examined 1 150 beetles collected in seven states of the Mexican Republic, and found 19 species of klinckowstroemiid mites associated with 168 passalids, that belong to 28 different species in 15 genera. Host specificity between species of both groups does not exist, as one species of passalid beetle can have several different symbionts; conversely, a given mite species can associate with passalid beetles of different species and even of different genera. This way, Odontotaenius zodiacus has been found associated with mites of seven species of the genus Klinckowstroemia. Besides, Klinckowstroemia valdezi is associated with five species of passalids. Furthermore, two and even three different species of mites have been found on one host beetle (synhospitality). The lack of congruence between the phylogenies of the mites and that of the beetles indicates that a process of co-adaptation by colonization is going on, because the association is due to the resources that passalid beetles can offer to the mites, like transportation, food and refuge. Since these resources are not host-specific, the klinckowstroemiid mites can climb onto virtually any species of passalid beetles occurring on the same habitat. Rev. Biol. Trop. 60 (2): 599-609. Epub 2012 June 01.

Realizamos un análisis de la relación que existe entre los ácaros Klinckowstroemiidae y los coleópteros Passalidae, puesto que los ácaros adultos se recolectaron exclusivamente sobre pasálidos (huéspedes). Asimismo, examinamos 1 150 coleópteros recolectados en siete estados de la República Mexicana, y encontramos 19 especies de ácaros klinckowstroémidos asociados con 168 de ellos, pertenecientes a 28 diferentes especies de 15 géneros distintos. Estos táxones establecen una relación simbiótica llamada foresia. No existe una especificidad entre las especies de ambos grupos, debido a que una especie de pasálido puede tener varios forontes, y una especie de ácaro puede asociarse a pasálidos de diferentes géneros y especies. Un ejemplo es Odontotaenius zodiacus que presentó a siete especies de Klinckowstroemia asociadas, y por otro lado, Klinckowstroemia valdezi se encuentra asociada a cinco especies de pasálidos. Además, dos o hasta tres especies de ácaros se encontraron sobre un coleóptero huésped (synhospitality). La falta de congruencias entre la filogenia de los ácaros con la de los pasálidos nos indica que se está produciendo un proceso de coadaptación por colonización, y que ésta asociación se debe a los recursos que le brindan los pasálidos a los ácaros: transporte, refugio y alimento. Como estos recursos no son específicos para algún huésped los klinckowstroémidos se suben a cualquier especie de pasálido.

[Co-adaptation between mites (Arachnida: Klinckowstroemiidae) and Passalidae beetles (Insecta: Coleoptera)]. / Coadaptación entre los ácaros (Arachnida: Klinckowstroemiidae) y coleópteros Passalidae (insecta: Coleoptera).

Mites of the family Klinckowstroemiidae establish an association with beetles of the family Passalidae known as phoresy. In order to obtain information about this association, we analyzed the relationship between mites of the family Klinckowstroemiidae and beetles of the family Passalidae, as adult mites have been exclusively collected from host beetles. We examined 1 150 beetles collected in seven states of the Mexican Republic, and found 19 species of klinckowstroemiid mites associated with 168 passalids, that belong to 28 different species in 15 genera. Host specificity between species of both groups does not exist, as one species of passalid beetle can have several different symbionts; conversely, a given mite species can associate with passalid beetles of different species and even of different genera. This way, Odontotaenius zodiacus has been found associated with mites of seven species of the genus Klinckowstroemia. Besides, Klinckowstroemia valdezi is associated with five species of passalids. Furthermore, two and even three different species of mites have been found on one host beetle (synhospitality). The lack of congruence between the phylogenies of the mites and that of the beetles indicates that a process of co-adaptation by colonization is going on, because the association is due to the resources that passalid beetles can offer to the mites, like transportation, food and refuge. Since these resources are not host-specific, the klinckowstroemiid mites can climb onto virtually any species of passalid beetles occurring on the same habitat.

Troglomorphism, trichobothriotaxy and typhlochactid phylogeny (Scorpiones, Chactoidea): more evidence that troglobitism is not an evolutionary dead-end.

The scorpion family Typhlochactidae Mitchell, 1971 is endemic to eastern Mexico and exclusively troglomorphic. Six of the nine species in the family are hypogean (troglobitic), morphologically specialized for life in the cave environment, whereas three are endogean (humicolous) and comparably less specialized. The family therefore provides a model for testing the hypotheses that ecological specialists (stenotopes) evolve from generalist ancestors (eurytopes) and that specialization (in this case to the cavernicolous habitat) is an irreversible, evolutionary dead-end that ultimately leads to extinction. Due to their cryptic ecology, inaccessible habitat, and apparently low population density, Typhlochactidae are very poorly known. The monophyly of these troglomorphic scorpions has never been rigorously tested, nor has their phylogeny been investigated in a quantitative analysis. We test and confirm their monophyly with a cladistic analysis of 195 morphological characters (142 phylogenetically informative), the first for a group of scorpions in which primary homology of pedipalp trichobothria was determined strictly according to topographical identity (the "placeholder approach"). The phylogeny of Typhlochactidae challenges the conventional wisdom that ecological specialization (stenotopy) is unidirectional and irreversible, falsifying Cope's Law of the unspecialized and Dollo's Law of evolutionary irreversibility. Troglobitism is not an evolutionary dead-end: endogean scorpions evolved from hypogean ancestors on more than one occasion. © The Willi Hennig Society 2009.