Fernando Pérez-Miles

• PhD
• Profesor Titular de Entomología at Universidad de la República de Uruguay

Actinopus Perty, 1833 is characterized and redescribed, including 80 species occurring from Panama to Argentina. Eighteen previously known species are redescribed: A. rufipes (Lucas, 1834); A. longipalpis C. L. Koch, 1842; A. nattereri (Doleschall, 1871); A. crassipes (Keyserling, 1891); A. robustus (O. Pickard-Cambridge, 1892); A. wallacei F. O. P...

Activity and occupancy dynamics of spiders are topics that have received little attention and are compounded by anecdotal field data, especially in Theraphosidae that are generally nocturnal. Due to potential vulnerability outside their burrows, it is expected that individuals remain in the safety of their shelters most of the time and because thei...

Mygalomorphs depend on thermal microhabitats for successful behavior, but their thermal biology is still poorly known. Grammostola vachoni Schiapelli and Gerschman, 1961 is an endemic tarantula from Argentina and it is listed as vulnerable in the IUCN Red List. However, little is known about its biology; therefore, we attempted to explore the therm...

Regulation of energy and water balance are primary components of homeostasis in all organisms. But the processes associated with such homeostasis can be costly and affect the fitness of individuals. As a result, individuals from variable environments are expected to invest more in compensatory mechanisms to maintain homeostasis than individuals fro...

We describe and illustrate a new species of tarantula of the genus Euathlus Ausserer, 1875, Euathlus walteri sp. nov. This species represents the first record for the genus in Tarapacá region, being the northernmost limit of its known distribution in Chile. Known and potential distribution are provided. Precipitations and altitude are the most impo...

We describe and illustrate a new tarantula species of the genus Plesiopelma from Lavalleja and Maldonado, Uruguay. Plesiopelma arevaloae sp. nov. is distinguished from other known species by morphological characters and molecular evidence.

The genus Jambu gen. nov. is proposed based on two new species: Jambu paru gen. et sp. nov. and Jambu manoa gen. et sp. nov. Hapalopus butantan is transferred to Jambu; consequently, Jambu butantan gen. et comb. nov. is proposed. The geographic distribution of J. butantan is extended on the basis of new material collected. The new genus and the new...

Two new genera, Bermejoa gen. nov. and Isiboroa gen. nov. are described to house the species Bermejoa zoeae sp. nov. and Isiboroa hamelae sp. nov., respectively. Two new species of existing genera are also described: Plesiopelma manni sp. nov. and Reversopelma herzogi sp. nov. Homoeomma peruvianum (Chamberlin, 1916) and Acanthoscurria sacsayhuaman...

New World tarantulas present a unique and conspicuous defen- sive mechanism: the release of urticating setae. The morpholog- ical differentiation of the types of setae suggests their distinct use, with two defensive mechanisms proposed: active defence against potential predators and passive defence against other arthropods, through the incorporatio...

Acanthoscurria cordubensis (fig. 1A) and Eupalaestrus weijenberghi (fig. 1B) are two tarantulas which inhabit meadows in Uruguay. During the last decades, there has been intense modifications of natural grassland environments, mainly due to agriculture and forestation. We decided to compare the presence and distribution of both species from results...

New World tarantulas present a unique and conspicuous defen sive mechanism: the release of urticating setae. The morpholog ical differentiation of the types of setae suggests their distinct use, with two defensive mechanisms proposed: active defence against potential predators and passive defence against other arthropods, through the incorporation...

The family Nemesiidae was once among the most species-rich of mygalomorph spider families. However, over the past few decades both morphological and molecular studies focusing on mygalomorph phylogeny have recovered the group as paraphyletic. Hence, the systematics of the family Nemesiidae has more recently been controversial, with numerous changes...

Spiders are perfect model for developmental stage and growth studies because the juvenile period is broken into instars. Theraphosidae family, are largest and longest-lived spiders and females continue to grow and molt over the sexually mature stage is reached. However, their development and growth are still unknown. Thus, our objective was describ...

Theraphosid tarantulas are large spiders that bear dense hairy adhesive pads on the distal parts of their legs: scopula and claw tufts. These structures allow them to climb on vertical smooth surfaces and contribute to prey capture. While adult females and juveniles remain most of the time in their burrows, adult males actively walk searching for f...

Most of the New World tarantulas feature specialized setae as a defense mechanism. Two mechanisms of defense have been proposed for the urticating setae (US): active defense against potential predators, and passive defense against other arthropods by incorporating the US to the molting mat and egg sacs. Uruguayan tarantulas present three different...

The Theraphosidae are the most famous and diverse mygalomorph spiders, and include some of the largest arachnids on earth. Their unique defense mechanisms, predatory tactics, reproductive strategies and ecological adaptations are displayed by a wide range of terrestrial, burrowing and arboreal species. These arachnids are familiar to the general pu...

Tarantulas are large spiders with adhesive setae on their legs, which enable them to climb on smooth vertical surfaces. The mechanism proposed to explain adhesion in tarantulas is anisotropic friction, where friction is higher when the leg pushes compared to when it pulls. The static friction of live theraphosid spiders on different surfaces and at...

Theraphosinae is the most diverse subfamily of tarantulas in the world, with more than 500 known species. The group is endemic to the New World and its geographic distribution ranges from Southern North America to temperate zones of South America. The largest and most long-lived spiders in the world belong to this subfamily. They inhabit almost all...

The mygalomorph spiders of the family Theraphosidae, commonly named as tarantulas, are one of the most famous and diverse groups of arachnids, which include the largest spider species in the world. Theraphosidae contains almost 1000 species from all continents, except Antarctica and includes burrowing, terrestrial and arboreal taxa with diverse eco...

Background The mechanics and energetics of spider locomotion have not been deeply investigated, despite their importance in the life of a spider. For example, the reproductive success of males of several species is dependent upon their ability to move from one area to another. The aim of this work was to describe gait patterns and analyze the gait...

The recent rediscovery and examination of the holotype of Neischnocolus panamanus Petrunkevitch, 1925 and its comparison with type material of the genera Barropelma Chamberlin, 1940 and Ami Pérez-Miles, 2008 led us to establish their generic synonymy. Ami species and the monotypic Barropelma parvior (Chamberlin & Ivie, 1936) fit with the diagnostic...

The family of mygalomorph spiders Paratropididae Simon, 1889 is here reported for the first time for Colombia, where it is represented by three genera (Anisaspis, Paratropis, Stormtropis gen. n.) and eight species. One genus, Stormtropis, and six species constitute new taxa that are here diagnosed, described and illustrated. The geographical distri...

Background: For males of several terrestrial spiders the reproductive success depends to their locomotors performances. However, their mechanics of locomotion has been scarcely investigated. Aim of this work was to describe the gait patterns, analyse the gait parameters, the mechanics of locomotion and the energy saving mechanisms of Eupalaestrus w...

Background: For males of several terrestrial spiders the reproductive success depends to their locomotors performances. However, their mechanics of locomotion has been scarcely investigated. Aim of this work was to describe the gait patterns, analyse the gait parameters, the mechanics of locomotion and the energy saving mechanisms of Eupalaestrus w...

This is the first study about trophic traits of Grammostola vachoni, a threatened theraphosid spider endemic to the mountain systems of central Argentina. Four prey types were used in experiments: crickets, cockroaches, beetle larvae and adult beetles. Grammostola vachoni was observed to eat at a rate of about once every 11 days, with the mean tota...

Biological corridors are connections which link habitats in a regional scale, allowing the gene flow between populations. The Uruguay River comprises riverside and insular riparian forests along subtropical to temperate zones passing through different biogeographic provinces. The aim of this study was to characterise the spider fauna from the Urugu...

The female sex of Ami bladesi Pérez-Miles et al., 2008 is described, based on three specimens from northeastern Costa Rica and one specimen from the type locality in Panama. It is the first record of this species and genus from Costa Rica. In addition to the modified urticating hairs of type I, urticating hairs of type III were found in both female...

Context Bioindicators are used for conservation prioritisation by means of spatial comparisons of a site value, or monitoring of ecosystem recovery or response to management. Spiders are characterised by their selection of quality habitats and guild responses to environmental change. However, they have only occasionally been used as bioindicators....

We studied the morphology of scopula, claw tufts and a scopula-like feature (pseudoscopula) of tarsi on representatives of all Mygalomorphae spider families. The pseudoscopula is constituted by groups of non-microtriched conical setae. The taxonomic distribution of all these features was studied and mapped on a recent phylogeny of Mygalomorphae and...

The infraorder Mygalomorphae comprises almost 3000 species. It is widely distributed all over the world, and about one third of the species included in this infraorder is represented in the Neotropics. The knowledge on several aspects of the biology of Mygalomorphae is relatively scarce in comparison with the Araneomorphae. However, recent studies...

La lista de especies prioritarias para la conservación en Uruguay resulta un insumo imprescindible para la gestión de la biodiversidad a nivel nacional y regional. Actualmente esta lista contiene vertebrados, plantas vasculares y moluscos continentales, siendo estos últimos los únicos representantes de invertebrados. Los arácnidos son predadores “t...

We present a mtDNA gene tree of tarantula spiders (Araneae: Mygalomorphae: Theraphosidae) based on the mitochondrial 16S-tRNA (leu)-ND1 gene region as a promising initial molecular hypothesis to clarify the taxonomy of the largest subfamily, Theraphosinae. Many species of this New World subfamily are traded widely as exotic pets, yet few scientific...

A bilateral gynandromorph specimen of the tarantula Pterinochilus murinus Pocock, 1897 is here described and illustrated. In addition, encounters with conspecific females were studied. The possible explanations for this case of gynandry are discussed. This constitutes the first formal report of gynandry in a mygalomorph spider.

Pisauridae, Trechaleidae, and Lycosidae constitute part of the Lycosoidea clade that includes a diverse range of wandering spider species that inhabit terrestrial and semi-aquatic environments. Phylogenetic studies of these three families based on morphological and behavioural traits have produced contradictory results on their evolutionary relatio...

We studied the activity and prey capture of adult females and juveniles of the tarantula Eupalaestrus weijenberghi in the field. Their activity starts at sunset and continues during the early night hours. Tarantulas leave the burrow only for brief periods, mainly for prey capture, and do not move more than 40 cm away from the burrow entrance. Activ...

Magnacarina gen. nov. from Mexico is described. Hapalopus aldanus West, 2000 from Nayarit, is transferred to the new genus with an emended diagnosis creating the new combination Magnacarina aldana comb. nov. Three new species are described: Magnacarina moderata Locht, Mendoza & Medina sp. nov. from Nayarit and Sinaloa; Magnacarina primaverensis Men...

A new monotypic Theraphosidae genus, Kankuamo Perafán, Galvis & Pérez-Miles, gen. n., is described from Colombia, with a new type of urticating setae. These setae differ from others principally by having a small distal oval patch of lanceolate reversed barbs. Males of Kankuamo gen. n. additionally differ by having a palpal bulb organ very divergent...

We studied the geographic distribution of theraphosid abdominal urticating setae types to test the presence of biogeographical patterns. Setae types were mapped on area cladograms recently proposed for the regionalization of the Neotropical region. We found some patterns which agree with some historical biogeography events and also some ecological...

Tarantulas are large spiders with adhesive setae on their legs, which enable them to climb on smooth vertical surfaces. The mechanism proposed to explain adhesion in tarantulas is anisotropic friction, where friction is higher when the leg pushes than when it pulls. However, previous studies and measurements of adhesion in theraphosids were perform...

The mygalomorph genus Grammostola (family Theraphosidae) is endemic to South America. The species Grammostola anthracina is one of the largest spiders in Uruguay and reputed to be the longest lived tarantula in the world. This nominal species has two distinct colour morphs comprising black and reddish-brown forms with controversial taxonomic status...

The presence of pheromones has been reported for several spider species but their persistence in field conditions has scarcely been studied. We test the activity and persistence of female sex cues outdoor in the tarantula Eupalaestrus weijenberghi (Thorell, 1894), using male courtship as an indicator of cue attraction. We studied female silk fields...

ABSTRACT The Cerro de Montevideo is a symbolic reference of Uruguay that currently presents an artificialised landscape with environmental deterioration. We used combined techniques including documentary analysis, cartography, remote sensing, biogeographical relict biota, digital recreation and estimated valuation of visual fragility to characteris...

THERAPHOSIDAE Resumen Las Theraphosidae son un grupo homogéneo de arañas migalomorfas que, en general, son de gran tamaño y presentan el cuerpo densamente cubierto de setas. Este grupo incluye 124 géneros y más de 950 especies de distribución principalmente gondwánica. Más de la mitad de las especies están representadas en el Nuevo Mundo, donde se...

Conservation biogeography involves the application of biogeographical principles and methods to conservation issues. The identification of areas of endemism is important for both historical biogeography and conservation. Mygalomorphs spiders have poor vagility, limited dispersal mechanisms and sedentary habits. In this study we use a panbiogeograph...

We propose the name Bumba as a new name for Maraca, preoccupied by Maraca Hebard, 1926 (Orthoptera). We describe and illustrate Bumba lennoni, a new theraphosid species from Caxiuanã, Pará, Brazil. This species differs from the other species of the genus in the extremely reduced keel on male palpal organ and in the higher number of labial and maxil...

The present study used the previously defined biogeographic provinces from Argentina as the starting point for a parsimony analysis of endemicity and cluster analysis. The goal of the study was to use a dataset of distributional patterns of mygalomorph spiders from Argentina to evaluate the historical relationships of the biogeographic provinces. T...

Based on a phylogenetic analysis we revised the Chilean tarantula genera Euathlus and Paraphysa. As results of our analyses, within a wider context of South American lineages, Paraphysa is synonymous of Euathlus, and Phrixotrichus is resurrected. Euathlus and Phrixotrichus are sister genera, supported by their shared palpal organ morphology, especi...

A new genus and species of a mygalomorph nemesiid spider collected in a hill of Northern Uruguay and in Araucaria forest at Southern Brazil is diagnosed, described and illustrated. A remarkable characteristic of the new genus is its dense body pubescence, unusual in most Nemesiidae. Also genital and somatic characters led to differentiate it from r...

Three new species of the monotypic genus Melloleitaoina Gerschman & Schiapelli, 1960 are described from northern Argentina: M. mutquina sp. n., M. uru sp. n. and M. yupanqui sp. n. The female specimen originally described as M. crassifemur is not conspecific with the male holotype and thus is removed from this species and described as M. uru sp. n....

En el presente trabajo se analizó la riqueza específica, abundancia y actividad de la comunidad de arañas Mygalomorphae en la Reserva Natural Sierra del Tigre, Buenos Aires, Argentina. Este ecosistema serrano alberga numerosas especies endémicas y es rico en fauna y flora nativa. La abundancia de arañas se muestreó mensualmente desde mayo de 2011 a...

Grammostola diminuta sp. nov. (Araneae: Theraphosidae) is described from northwestern Argentina; Grammostola vachoni Schiapelli and Gerschman 1961 is considered a senior synonym of Grammostola fossor syn. nov. Schmidt 2001 on the basis of material examined from the collection of the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (MACN...

When two similar species co-occur in time and space, strong mechanisms isolating them from each other are expected. Acanthoscurria suina Pocock, 1903 and Eupalaestrus weijenberghi (Thorell, 1894) are two sympatric and synchronic tarantulas that inhabit burrows in Uruguay's meadows. Here we test how and when reproductive isolation operates between t...

Summary Strong reproductive barriers are expected between similar species that co-occur in time and space. We experimentally analysed sexual interactions between the theraphosids Acanthoscurria suina and Eupalaestrus weijenberghi which met those conditions. Unexpectedly, males courted on heterospecific female cues. Furthermore, A. suina females see...

A generally common impression seems to be that the mygalomorphs have simple repertoires of behaviours, but many authors have concluded that this traditional portrayal of mygalomorph behaviours is misleading. An increasing number of studies of reproductive behaviour of mygalomorphs have revealed intricate and complex mechanisms of communication empl...

Adult males of Eupalaestrus weijenberghi (Thorell 1894) live only for few months, while females live many years and continue molting and growing. Hence, there is a strong female-biased operational sex-ratio. While males move massively during the brief mating season, females are sedentary and remain inside their burrows, which are sometimes very clo...

We describe two new species of the nemesiid spider genus Chaco from Rocha Province, Uruguay. These new species are diagnosed based on genital morphology, male tibial apophysis spination, and burrow entrance. We test cospecificity of one species, Chaco costai,via laboratory mating experiments. The new species are diagnosed and illustrated and habita...

Munduruku gen. nov. is proposed for the type species Munduruku bicoloratum sp. nov., from Juruti and Santarém, Pará, Brazil. The main diagnostic character of Munduruku gen. nov. is the presence of a subapical, lanceolate keel on the male palpal bulb, which is unique among the basal taxa of Theraphosinae with type III-IV urticating setae. The female...

A pesar de que se han publicado datos sobre aspectos ecológicos y/o de comportamiento reproductivo de algunas especies de migalomorfas, aún resta por conocer las características reproductivas de su mayoría. Catumiri parvum (Keyseling 1878) (Theraphosidae) y Stenoterommata platensis (Homlberg 1881) (Nemesiidae) son dos especies de migalomorfas abund...

Using the road tarantula Eupalaestrus weijenberghi (Thorell 1894), we tested the importance of the third pair of legs in male courtship behavior. Our results showed that the third pair of legs is essential for males to elicit female sexual receptivity. Males with their second pair of legs immobilized elicited receptive responses from females, but m...

Using the road tarantula Eupalaestrus weijenberghi (Thorell 1894), we tested the importance of the third pair of legs in male courtship behavior. Our results showed that the third pair of legs is essential for males to elicit female sexual receptivity. Males with their second pair of legs immobilized elicited receptive responses from females, but m...

This is the first record for the species Deinopis amica and for the family Deinopidae in Uruguay. The present study expands the known distribution of the species to the lower Uruguay River. Data on natural history of the species is provided.

Microstigmatidae are small ground-dwelling and free-living spiders. The present study reports on the copulatory behavior of Xenonemesia platensis Goloboff 1989, constituting the first report on sexual behavior of the Microstigmatidae. Our findings in X. platensis did not show evidence of pheromones associated with silk. The courtship behavioral uni...

The distributional history of the South American endemic genus Cyriocosmus (Araneae, Theraphosidae) was reconstructed, and a spatial analysis of vicariance was conducted. Results obtained with the software RASP (Reconstruct Ancestral State in Phylogenies), suggest that Cyriocosmus originated within an area currently represented by the biogeographic...

A panbiogeographical analysis of Mygalomorphae spiders was undertaken in order to determine generalized tracks and biogeographical nodes in the peripampasic orogenic arc. This arc comprises mountainous systems that harbour a high number of endemic species, while they exhibit biotic connections that have become fragmented probably during Tertiary te...

We described and analyzed the female sexual response in the tarantula Grammostola vachoni Schiapelli and Gerschman 1961 under three series of 10 experiments each with different situations for the male-female encounters: male free in terrarium but with no access to female; male confined into a glass cup at 30 cm of female burrow and; male confined i...

Theraphosid tarantulas, like all other spiders, secrete silk from spigots on the abdominal spinnerets. A few years ago, it was proposed that the large tarantula Aphonopelma seemanni could extrude silk from specialized spigots on the tarsi to help adhesion to vertical surfaces. This suggestion was later questioned because silk was not observed after...

The diversity, abundance, spatial distribution, and phenology of the mygalomorph spider community in the "Ernesto Tornquist" Strict Nature Reserve were analyzed in this study. Located in southwestern Buenos Aires, Argentina, the Reserve is representative of the Ventania system, which is a sigmoidal mountain belt 180 km in length. This exceptional h...

Acanthogonatus centralis Goloboff 1995 is a Neotropical nemesiid distributed in hilly zones of central Argentina. The biology of the Nemesiidae is almost unknown. We describe the courtship and mating of A. centralis based on eight observed matings (three males and five females). Male courtship involved scratching and beating the ground. These behav...

Intraspecific interactions of araneomorph spiders have received considerable attention, but there are few detailed studies on intraspecific interactions of mygalomorph spiders. Moreover, a thorough understanding of theraphosid biology and ecology is necessary from a conservation standpoint because natural populations may be threatened by habitat di...

Three species of Grammostola (Araneae, Mygalomorphae, Theraphosidae) from central Argentina are redescribed and illustrated and their geographic distributions are reported. A new synonymy between G. vachoni Schiapelli & Gerschman 1961 and G. schulzei (Schmidt 1994) n. syn. is proposed. We did not find zones of co-occurrence with the three species b...

The taxonomic status of four species of Avicularia Lamarck 1818 described from Uruguay: Avicularia anthracina (C.L. Koch 1842), Avicularia alticeps (Keyserling 1878), Avicularia parva (Keyserling 1878) and Avicularia tigrina (Pocock 1903) is discussed. The holotypes and/or original descriptions of these species were examined, and two taxonomic syno...

We describe and figure a new species of the genus Schismatothele Karsch, 1879 from Brazil, Amazonas state, to the north of Manaus. This species comprises the first male known for the genus and the first report of the genus Schismatothele for Brazil. The new species differs from the only known species, Schismatothele lineata Karsch, 1879 in the morp...