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Made available in DSpace on 2022-04-28T19:50:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-03-01 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 at the family-group level and the recognition of the supra-familial clade Nemesioidina. Indeed, in a recent study by Opatova and collaborators, six nemesiid genera were transferred to the newly re-established family Pycnothelidae. Despite these changes, 12 South American nemesiid genera remained unplaced, and classified as incertae sedis due to shortcomings in taxon sampling. Accordingly, we evaluate the phylogenetic relationships of South American nemesioid species and genera with the principle aim of resolving their family level placement. Our work represents the most exhaustive phylogenomic sampling for South American Nemesiidae by including nine of the 12 genera described for the continent. Phylogenetic relationships were reconstructed using 457 loci obtained using the spider Anchored Hybrid Enrichment probe set. Based on these results Nemesiidae, Pycnothelidae, Microstigmatidae and Cyrtaucheniidae are not considered monophyletic. Our study also indicates that the lineage including the genus Fufius requires elevation to the family level (Rhytidicolidae Simon, 1903 (NEW RANK)). In Pycnothelidae, we recognize/delimit five subfamilies (Diplothelopsinae, Pionothelinae (NEW SUBFAMILY), Prorachiinae (NEW SUBFAMILY), Pselligminae (NEW RANK), Pycnothelinae). We also transfer all the 12 South American nemesiid genera to Pycnothelidae: Chaco, Chilelopsis, Diplothelopsis, Flamencopsis, Hermachura, Longistylus, Lycinus, Neostothis, Prorachias, Psalistopoides, Pselligmus, Rachias. Additionally, we transferred the microstigmatid genus Xenonemesia to Pycnothelidae, and we propose the following generic synonymies and species transfers: Neostothis and Bayana are junior synonyms of Pycnothele (NEW SYNONYMY), as P. gigas and P. labordai, respectively (NEW COMBINATIONS); Hermachura is a junior synonym of Stenoterommata (NEW SYNONYMY), as S. luederwaldti (NEW COMBINATION); Flamencopsis is a junior synonym of Chilelopsis (NEW SYNONYMY), as C. minima (NEW COMBINATION); and Diplothelopsis is a junior synonym of Lycinus (NEW SYNONYMY), as L. ornatus and L. bonariensis (NEW COMBINATIONS). Considering the transferred genera and synonymies, Pycnothelidae now includes 15 described genera and 137 species. Finally, these results provide a robust phylogenetic framework that includes enhanced taxonomic sampling, for further resolving the biogeography and evolutionary time scale for the family Pycnothelidae. Sección Entomología Facultad de Ciencias Universidad de la República, Iguá 4225 Instituto de Investigaciones Biológicas Clemente Estable Ministerio de Educación y Cultura, Av. Italia 3318 Laboratório de Coleções Zoológicas Instituto Butantan, Av. Vital Brazil, 1500 Departamento de Biodiversidade Instituto de Biociências Universidade Estadual Paulista, Av. 24A, 1515 Department of Zoology Charles University Faculty of Science, Viničná 7 Instituto Nacional de Pesquisas da Amazônia Laboratório de Sistemática e Ecologia de Invertebrados do Solo, Av. André Araújo, 2936 – Petrópolis – Manaus Department of Entomology and Nematology University of California Davis, Academic Surge Building 1282 Departamento de Biodiversidade Instituto de Biociências Universidade Estadual Paulista, Av. 24A, 1515

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 their limited dispersal mechanism, usually by walking over short distances. Grammostola vachoni is an endemic tarantula from Argentina listed as Vulnerable specie by the IUCN. Changes in natural habitat of G. vachoni are detrimental for their survivorship. However, little is known about whether their occupancy dynamics and spatial distribution pattern are affected by different disturbances. In this study we evaluated whether disturbances in the natural habitat of G. vachoni affected the distribution patterns and adults abundance in different populations and determined activity patterns and refuge fidelity. It was observed that the spiders emerged after 9:30 pm and showed an exploratory behavior; females exhibited high refuge fidelity. Results showed that in disturbed habitats the spiders presented an aggregated distribution, whereas in undisturbed habitats spiders remained in settlements with greater distances between neighbors. Therefore, it can be concluded that the distribution patterns of G. vachoni are influenced by environmental disturbances to their natural habitat. These aspects are particularly important due to the conservation status of the spider, since the continual regression of mountain grassland in Argentina puts species viability at risk; especially in species with limited dispersal capability, a longer life cycle and sedentary habits such as G. vachoni. Fil: Schwerdt, Leonela Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: de Villalobos, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Pérez Miles, Fernando. Universidad de la República. Facultad de Ciencias; 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.-Cambridge, 1896; A. princeps Chamberlin, 1917; A. xenus Chamberlin, 1917; A. fractus Mello-Leitão, 1920; A. paranensis Mello-Leitão, 1920; A. pusillus Mello-Leitão, 1920; A. dubiomaculatus Mello-Leitão, 1923; A. trinotatus Mello-Leitão, 1938; A. cucutaensis Mello-Leitão, 1941; A. echinus Mello-Leitão, 1949; A. clavero Ríos-Tamayo & Goloboff, 2018; A. gerschiapelliarum Ríos-Tamayo & Goloboff, 2018; and A. palmar Ríos-Tamayo & Goloboff, 2018. Additionally, A. tarsalis Perty, 1833, the type species, A. insignis (Holmberg, 1881) and other 18 species recently described species from Argentina and Bolivia, are re-evaluated. Forty-two new species are described: Actinopus castelo sp. nov., A. apalai sp. nov., A. mairinquensis sp. nov., A. obidos sp. nov., A. buritiensis sp. nov., A. pinhao sp. nov., A. ducke sp. nov., A. hirsutus sp. nov., A. jaboticatubas sp. nov., A. confusus sp. nov., A. pampulha sp. nov., A. candango sp. nov., A. paraitinga sp. nov., A. cornelli sp. nov., A. vilhena sp. nov., A. harveyi sp. nov., A. itapitocai sp. nov., A. ipioca sp. nov., A. itaqui sp. nov., A. xingu sp. nov., A. mesa sp. nov., A. caxiuana sp. nov., A. utinga sp. nov., A. emas sp. nov., A. bocaina sp. nov., A. osbournei sp. nov., A. dioi sp. nov., A. tutu sp. nov., A. azaghal sp. nov., A. itacolomi sp. nov., A. parafundulus sp. nov., A. urucui sp. nov., A. reznori sp. nov., A. anselmoi sp. nov., A. guajara sp. nov., A. apiacas sp. nov., A. jamari sp. nov. from Brazil; A. laventana sp. nov. from Argentina and Uruguay; A. lomalinda sp. nov. from British Guiana and Colombia; A. concinnus sp. nov. from Venezuela and Brazil; A. pindapoy sp. nov. from Argentina; A. panguana sp. nov. from Peru. The females of A. dubiomaculatus and A. cucutaensis and the males of A. nattereri are described for the first time. New records are presented for A. clavero; A.crassipes; A. dubiomaculatus; A. fractus; A. gerschiapelliarum; A. nattereri; A. palmar; A. paranensis; A. princeps, A. pusillus, A. robustus and A. wallacei. Ten old species names are herein considered species inquirendae: A. caraiba (Simon, 1889); A. harti Pocock, 1895; A. liodon (Ausserer, 1875); A. nigripes (Lucas, 1834); A. pertyi Lucas, 1843; A. piceus (Ausserer, 1871); A. rojasi (Simon, 1889); A. rufibarbis Mello-Leitão, 1930; A. scalops (Simon, 1889) and A. valencianus (Simon, 1889). Most species presently recognized were included in 11 informal groups based mainly on male palpal characters. A key for these groups plus three species, not included in any group, but known from males, is presented.

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 females during the reproductive period. Adhesion and locomotion thus play important roles in the ecology and reproduction of these animals. In this paper, we review the current state of the knowledge on adhesion and locomotion in tarantulas, focusing on functional and evolutionary morphology.

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 from stable environments. Grammostola quirogai and Grammostola anthracina are two spiders of the Theraphosidae family that live in rocky-hill habitats in the Pampas ecoregion. Both species inhabit mesic environments with moderate rainy weather but different precipitation variability. G. quirogai only exists in rocky-hill habitats surrounded by prairies, far from oceanic and estuarine coasts. These habitats are exposed to higher and more variable precipitation rates due to a stronger influence of El Niño. In contrast, G. anthracina lives in areas with less heterogeneous precipitation rates, and its populations expand up to the Atlantic coast. In this study, we used these two species to explore the impacts of water deprivation on their metabolic rate and water loss. We did not detect changes in metabolic rate or differences in water loss as a result of a water restriction treatment in any of the species. However, the mean total values of evaporative water loss for our studied species were lower than that of xeric species. These results provide evidence that the total evaporative water loss in tarantulas may not be related to environmental characteristics, as it has been widely reported among insect species.

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 thermal biology of juveniles and adult females of G. vachoni under laboratory conditions. We characterized the preferred temperatures, evaluated the relationship between temperature and locomotor performance, and calculated the thermal sensitivity. Individuals showed a peak temperature preference and spent 40% of the total time at 25?29 °C; we did not find any significant differences in temperature preference between juveniles and females. We found that locomotor performance is strongly affected by high temperatures. Different sprint speeds of juveniles and females were found at 5, 35, and 40 °C. The highest thermal sensitivity was recorded in the lowest temperature range and thermal sensitivity was lowest in the highest temperature ranges. Our results are relevant in the context of climate change, because thermal parameters constitute a useful tool to explore some possible effects of this change on body temperature and thus the physiological performance and vulnerability of ectotherms like G. vachoni. Fil: Schwerdt, Leonela Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: de Villalobos, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Pérez Miles, Fernando. Universidad de la República. Facultad de Ciencias; Uruguay Fil: Ferretti, Nelson Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina

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 different inclines was measured and compared between burrowing and arboreal species to test the hypothesis of higher friction in arboreal tarantulas. We analyzed the complementary participation of claw tufts and scopulae of anterior and posterior legs when the tarantula climbs. We also considered the morphology of scopulae and claw tufts setae and compared with similar structures in other families. Adhesive setae, as well as some other setae types found on ventral tarsi are described and characterized. The adhesive face of setae varied in the orientation in different parts of the tarsi, and this variation is more conspicuous in the spiders that have only claw tufts or scopulae. The mechanics of climbing in association with the biological characteristics of the species are analyzed. We discuss the association of adhesive scopulae and claw tufts with burrowing/cursorial mygalomorphs as within Theraphosidae, as was suggested for free-hunter spiders. The morphology, functions, and evolution of scopula and claw tufts are discussed in this chapter.

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 ecological adaptations and natural histories. Since the description of the family in 1869 their systematics was largely based on the study of morphological characters, and many authors agreed in the chaotic situation of their taxonomy. First phylogenetic studies were also based on morphological characters and molecular studies only started in the twenty-first century. Most authors recognize 12–13 subfamilies in the world; 5 of them occur in the New World. The most diverse subfamily, Theraphosinae includes about a half of the known species of tarantulas. In this chapter we introduce the phylogenetic position of the Theraphosidae within the Araneae, the general characteristics of the tarantulas including taxonomical, evolutionary and biological aspects of the group. We analyze Theraphosidae diagnostic characters and the affinities with other families and discuss the intrafamilial relationships and subfamilial characteristics focusing in New World groups.

The female sex of Ami bladesiPerez-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 females and males from Costa Rica and Panama. Notes on the distribution, ecology, and behaviour of A.bladesi are included.

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 studies on them exist, and the robustness of many supposed taxonomic groupings is debatable. Yet the validity of taxon names and knowledge of their distinctiveness is vital for trade regulation, most notably for the Neotropical genus Brachypelma Simon 1891, which is listed under CITES (Appendix II, see online supplemental material, which is available from the article's Taylor & Francis Online page at https://doi.org/10.1080/14772000.2017.1346719). The use of molecular markers for tarantula taxonomy has been limited until recently, with most previous studies relying on morphological methods. Our findings, from newly collected molecular data, have several nomencl...

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 relationships. To resolve their relationship, we constructed a molecular phylogeny based on five mitochondrial and three nuclear genes. We found support for the sister group relationship between Lycosidae and Trechaleidae. In contrast to previous findings, our results suggest that Pisauridae is not monophyletic, and that Dolomedes forms its own group. Both Pisauridae and Trechaleidae contain species that provide nuptial gifts. In combination with sampling of more species for this trait, our results provide a phylogenetic framework for assessing the evolution of nuptial gift giving in spiders.

Many adult male spiders have silk glands which are not associated with the spinnerets. They occur on the anterior margin of the genital furrow and are used during the building of the sperm web and sperm droplet induction. These epiandrous glands exit the body through ducts which lead to specialized spigots. In the taxon Mygalomorphae, the presence of epiandrous spigots is just reported for a couple of species but their morphology has not been investigated. In this paper we provide a detailed study of the ultrastructure morphology of eighteen species belonging to eight families using light and scanning electron microscopy (SEM). We describe and present images of the epiandrous spigots above the genital opening. Also, we compare the morphology of spigots between families and describe the epiandrous glands through histology., Centro de Estudios Parasitológicos y de Vectores

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 parameters of Eupalaestrus weijenberghi (Araneae, Theraphosidae) in order to investigate the mechanics of their locomotion and the mechanisms by which they conserve energy while traversing different inclinations and surfaces. Methods Tarantulas were collected and marked for kinematic analysis. Free displacements, both level and on an incline, were recorded using glass and Teflon as experimental surfaces. Body segments of the experimental animals were measured, weighed, and their center of mass was experimentally determined. Through reconstruction of the trajectories of the body segments, we were able to estimate their internal and external mechanical work and analyze their gait patterns. Results Spiders mainly employed a walk-trot gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected regarding the different planes or surfaces with respect to duty factor, time lags, stride frequency, and stride length. However, postural changes were observed on slippery surfaces. The mechanical work required for traversing a level plane was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all of the total mechanical work. The internal work was extremely low and did not rise as the gradient increased. Discussion Our results support the idea of considering the eight limbs functionally divided into two quadrupeds in series. The anterior was composed of the first two pairs of limbs, which have an explorative and steering purpose and the posterior was more involved in supporting the weight of the body. The mechanical work to move one unit of mass a unit distance is almost constant among the different species tested. However, spiders showed lower values than expected. Minimizing the mechanical work could help to limit metabolic energy expenditure that, in small animals, is relatively very high. However, energy recovery due to inverted pendulum mechanics only accounts for only a small fraction of the energy saved. Adhesive setae present in the tarsal, scopulae, and claw tufts could contribute in different ways during different moments of the step cycle, compensating for part of the energetic cost on gradients which could also help to maintain constant gait parameters.

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 total number of prey consumed per spider during the experimental period being 2.7. Latency to the first attack was similar for crickets, cockroaches and beetle larvae, but was shorter for adult beetles. Feeding time was significantly longer for crickets and beetle larvae. Mass gain was significantly different among prey types. Feeding effectiveness and ingestion rate were significantly higher for crickets. A significant positive correlation for feeding effectiveness and ingestion rate with prey mass and the initial spider mass was also found. Fil: Schwerdt, Leonela Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Pompozzi, Gabriel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; Argentina Fil: de Villalobos, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Pérez Miles, Fernando. Universidad de la República. Facultad de Ciencias; Uruguay

BackgroundThe 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 parameters ofEupalaestrus weijenberghi(Araneae, Theraphosidae) in order to investigate the mechanics of their locomotion and the mechanisms by which they conserve energy while traversing different inclinations and surfaces.MethodsTarantulas were collected and marked for kinematic analysis. Free displacements, both level and on an incline, were recorded using glass and Teflon as experimental surfaces. Body segments of the experimental animals were measured, weighed, and their center of mass was experimentally determined. Through reconstruction of the trajectories of the body segments, we were able to estimate their internal and external mechanical work and analyze their gait patterns.ResultsSpiders mainly employed a walk-trot gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected regarding the different planes or surfaces with respect to duty factor, time lags, stride frequency, and stride length. However, postural changes were observed on slippery surfaces. The mechanical work required for traversing a level plane was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all of the total mechanical work. The internal work was extremely low and did not rise as the gradient increased.DiscussionOur results support the idea of considering the eight limbs functionally divided into two quadrupeds in series. The anterior was composed of the first two pairs of limbs, which have an explorative and steering purpose and the posterior was more involved in supporting the weight of the body. The mechanical work to move one unit of mass a unit distance is almost constant among the different species tested. However, spiders showed lower values than expected. Minimizing the mechanical work could help to limit metabolic energy expenditure that, in small animals, is relatively very high. However, energy recovery due to inverted pendulum mechanics only accounts for only a small fraction of the energy saved. Adhesive setae present in the tarsal, scopulae, and claw tufts could contribute in different ways during different moments of the step cycle, compensating for part of the energetic cost on gradients which could also help to maintain constant gait parameters.

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. Here, we present a phylogenetic study based on molecular characters (cytochrome c oxidase subunit I) of haplotypes of G. anthracina and closely related species. Our analysis together with new morphological data and biogeographical information indicates that the two morphs of G. anthracina constitute different species that are not sister to each other. Consequently, a new species, Grammostola quirogai is described, diagnosed and illustrated to encompass the black morph. Phylogenetic relationships and new taxonomic characters for Grammostola species included in this study are discussed.

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.

Locomotor and physiological performance of ectotherms are affected by temperature. Thermoregulation is achieved by changes in behavior and the selection of micro-habitats with adequate temperatures to maintain the body temperature (Tb) within a range of preference. Apart from this temperature dependence at spatial scales, ectotherms are also affected by temperature at temporal scale. For instance, ectotherms can only be active some months of the year, particularly in temperate environments. Tarantulas are ectotherms that live in burrows most of their life. Nevertheless, after the sexual maturation molt, males leave their refugia and start a wandering life searching for females to mate. The reproductive period varies among species. In some species walking males are seen in late spring or early summer, while in other species males are only seen during fall or winter. Apart from the differences in lifestyles after maturation, tarantulas exhibit sexual dimorphisms in longevity and body mass, having smaller, shorter-lived males. Thus, to optimize energetic budgets, decreasing thermoregulation costs, we hypothesize and examine a putative correlation between an individual's preferred body temperature (Tpref) and the environmental temperature during the reproductive period. Hence, we characterize Tpref in seven tarantula species and analyze which factors (i.e., time of day, body mass, and sex) correlated with it. Furthermore, we assess putative correlated evolution of Tpref with ambient temperature (minima, mean, and maxima) during the reproductive period by means of phylogenetic independent contrasts. We did not find differences in thermal preferences between sexes; and only one species, Acanthoscurria suina, exhibited diel differences in Tpref. We found evidence of correlated evolution between Tpref and minimum temperature during the reproductive period among all seven species studied herein. Our results show that the reproductive period is constrained by thermal preferences, dictating when males can start their wandering life to mate.

Context. Bioindicators are used for conservation prioritization by means of spatial comparisons of a site value, or monitoring of ecosystem recovery or response to management. Spiders are characterized by their selection of quality habitats and guild responses to environmental change. However, they have only occasionally been used as bioindicators. Grammostola vachoni is an endemic tarantula that only occurs in the grasslands of the mountainous system in central Argentina and it is included in the Red List of the IUCN as Vulnerable.Aims. In this study, we performed a characterization of the microhabitat of G. vachoni at sites with different disturbance regimes and we analyzed the potential use of this species as a bioindicator of mountain grassland health.Methods. We determined the microhabitat characteristics around their refuges by mean of the soil parameters, as well as the composition and structure of vegetation and amount of refuge available.Key results. We found significant differences in the number of individuals and the percentage of occupation between sites. No significant differences were recorded in the soil characteristics and occupation of G. vachoni but we found that the composition of vegetation, and the heterogeneity and diversity of plants are influenced by different disturbance regimes, altering the distribution of spiders.Conclusions. Our results are consistent with those of other studies where the spiders have proved to be good bioindicators of different disturbances and we propose for the first time a Theraphosidae species for evaluating the state or health of a natural grassland.Implications. The information reported in this study is very important to provide data for a future re-categorization of G. vachoni for the Red List of IUCN. Also, we add new component of ecosystems for to use as indicator, open up the possibility for new research for the same and other species of a grasslands of the mountainous system. Fil: Schwerdt, Leonela Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: de Villalobos, Ana Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Pérez Miles, Fernando. Universidad de la República. Facultad de Ciencias; Uruguay

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 performed using dead specimens. To test their ability to climb, we studied static friction of live theraphosid spiders on different surfaces and at different inclines. We compared burrower with arboreal species to test the hypothesis of higher friction in arboreal tarantulas. We found a complementary participation of claw tufts and scopula of anterior and posterior legs when the tarantula climbs. The mechanics of climbing in association with the biological characteristics of the species are discussed., Summary: We test friction as a proxy of adhesion, comparing arboreal and burrower tarantulas climbing on different surfaces and at different angles.

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 characterise its pre-Hispanic ecological landscape: a grassy matrix with large patches and corridors of grasslands and woody vegetation, with an estimated intermediate-level visual fragility. The physiognomic changes would have initiated since ca. 1520, much earlier than was formerly proposed (1851), due to supply of firewood from native forests to vessels and livestock introduction by Europeans. Landscape artificialisation by urbanisation and industrialisation was intensified since 1870. Environmental degradation has increased since 1930. For the first time, cryptozoic arachnofauna, visual fragility and digital satellite photographic recreations were included in an histori...

Summary 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. Activity characteristics are analysed and discussed.

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 “tope” y reflejan lo que sucede a otros niveles de la trama trófica. En Uruguay se han identificado algunos problemas en cuanto a la conservación de los arácnidos, de los cuales las principales amenazas son la modificación y fragmentación de hábitat y el comercio ilegal de especies. El objetivo fue elaborar una lista de especies de arácnidos prioritarias para la conservación en Uruguay. Se realizaron una serie de talleres con expertos aracnólogos donde se consensuaron 7 criterios para definir especies prioritarias y se conformó una lista en base a éstos. Se identificaron 42 especies de arácnidos prioritarias para la conservación en Uruguay, de las cuales 35 son arañas, 4 son escorpiones, 2 opiliones y 1 solífugo. La elaboración de esta lista contribuirá a mejorar el estado del conocimiento de la biodiversidad de invertebrados a nivel nacional. Arachnids with priority for conservation in Uruguay. The list of species with priorities for conservation in Uruguay is an essential input for biodiversity management. Currently the list includes vertebrates, vascular plants and continental mollusks, of which the last group is the only representative of invertebrates. Arachnids are top predators that reflect what is happening at the oth201er levels of the trophic web. Some problems about arachnids’ conservation have been identified in Uruguay, mostly related to habitat reduction and modification and traffic of species. The objective of the present study was to elaborate a list of arachnids with priority of conservation in Uruguay. We organized a series of workshops with arachnology experts, agreed in seven criteria to define priority species and created the list. We identified 42 arachnids with priority of conservation in Uruguay. Thirty-five are spiders, four are scorpions, two are harvestmen and one is a camel spider. The creation of this list generates an antecedent for these groups that will contribute to improve the knowledge of invertebrate biodiversity in our country and the region.

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 developed all over the world, but especially in the Neotropical region, are continuously contributing to add information on foraging strategies, communication, reproductive biology, habitat selection, and defenses against natural enemies, minimizing the differences in the status of knowledge between these groups. In this chapter, we review some the main topics on Mygalomorphae biology, including behavior and ecology.

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 maxillary cuspules. Females additionally differ in the spermathecal morphology. As a consequence of the name replacement, three new combinations are established.

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 related genera. The habitat is characterized by a tubular burrow followed by an aerial tubular portion made with silk and vegetation. The sexual behaviour is briefly described from a copula between the types, observed in the laboratory.LSID: zoobank.org:pub: D5A6D7EA-19DD-4427-E6A41162EE4E.

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.; M. crassifemur is redescribed. All species are diagnosed, illustrated and a key to species is provided.

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. The analyses showed the following relationships: Yungas and Puna; Pampa and Chaco, Monte and Prepuna; Parana Forest and Araucaria angustifolia Forest; Central and Subandean Patagonia. Biogeographical regionalizations are useful as general reference models and their heuristic value should be explored by examining the geographical distribution of other taxa. Fil: Ferretti, Nelson Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: Pérez Miles, Fernando. Universidad de la República. Facultad de Ciencias; Uruguay Fil: Gonzalez, Alda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina

The recent rediscovery and examination of the holotype of Neischnocolus panamanusPetrunkevitch, 1925 and its comparison with type material of the genera BarropelmaChamberlin, 1940 and AmiPerez-Miles, 2008 led us to establish their generic synonymy. Ami species and the monotypic Barropelma parvior (Chamberlin & Ivie, 1936) fit with the diagnostic characters of Neischnocolus, with the presence of modified type I urticating setae and the singular spermathecal morphology. B. parvior is considered a junior synonym of N. panamanussyn. nov. based on genital organ morphology and geographical location. Ami bladesi Perez-Miles, Gabriel & Gallon, 2008 is also considered a junior synonym of Neischnocolus panamanussyn nov. based on genital organ morphology and geographical location. As a consequence, of the synonymies of the genera Barropelma and Ami with Neischnocolus, seven new combinations are created: N. amazonicacomb. nov., N. armihuarensiscomb. nov., N. caxiuanacomb. nov., N. obscuruscomb. nov., N. pijaoscomb. nov., N. weinmannicomb. nov. and N. yupanquiicomb. nov.

Summary 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 in two conditions: protected and exposed and in both we found a long persistence of sex signals, up to 55 and 46 days, respectively. We discuss the nature and adaptive significance of these cues.

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 employed by this group. Our objective was to provide a synthetic treatment of the literature published in the last 21 years about sexual behaviour of mygalomorph spiders, in order to contribute in improving our understanding on the widespread and unique behaviours they exhibit. We provide a brief introduction to reproductive behaviour of mygalomorph spiders, and then examine some of the general patterns of courtship and mating behaviours known on some mygalomorph families. Fil: Ferretti, Nelson Edgardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Universidad Nacional de La Plata; Argentina Fil: Pompozzi, Gabriel Alejandro. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina Fil: Copperi, Sofia. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina Fil: Gonzalez, Alda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Estudios Parasitológicos y de Vectores (i); Argentina. Universidad Nacional de La Plata; Argentina Fil: Perez Miles, Fernando. Universidad de la Republica; Uruguay

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 seemed to be more receptive to heterospecific males than conspecific ones in early courtship. Although precopulatory confusion occurred, no interspecific copulations were observed, which indicate that reproductive barriers operate.

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 spermathecae consist of two spheroid receptacles with funnel-shaped necks, each of which bears a sclerotized area. In both sexes, the abdomen is remarkably patterned, an uncommon feature in adults of New World theraphosids. Both the bulbus lanceolate keel and the abdominal color pattern are hypothesized as synapomorphies of the genus. Munduruku gen. nov., é proposto para a espécie-tipo Munduruku bicoloratum sp. nov., de Juruti, e Santarém, Pará, Brasil. O principal caráter diagnóstico de Munduruku gen. nov. é a presença de uma quilha subapical lancelotada no bulbo copulatório do macho, único no grupo basal de Theraphosinae com cerdas urticantes do tipo III-IV. A espermateca da fêmea consiste em dois recipientes esferóides com pescoço em forma de funil, cada um dos quais tendo uma área esclerotizada. Em ambos os sexos, o abdômen apresenta um padrão de colorido característico, o que é incomum em adultos de terafosídeos do Novo Mundo. Tanto a quilha lanceolada do bulbo quanto o padrão de colorido do abdômen são hipotetizados como sinapomorfias do gênero.

Magnacarina primaverensis Mendoza & Locht sp. nov. urn:lsid:zoobank.org:act:FF12650D-1E0E-43A6-9056-D98A65A794E4 Figs 8–12, 16 Diagnosis Magnacarina primaverensis sp. nov. differs from M. cancer sp. nov. in the general shape of the male palpal bulb, with prolateral inferior keel distally thinner and rounded, as well as in possessing prolateral accessory keels, and retrolateral apophysis slendering towards apex. Females differ in possessing a wider and longer spermatheca. M. primaverensis sp. nov. differs from M. aldana comb. nov. in possessing a slightly developed accessory apophysis; in a higher number of prolateral accessory keels, wider prolateral inferior keel and an inconspicuous male palpal tibia retrolateral process. Females differ in the endites posteriorly wider and rounded. Both sexes differ in a slightly orange carapace, with black cephalic area. M. primaverensis sp. nov. differs from M. moderata sp. nov. in having retrolateral nodule of megaspines, a male bulb with secondary projection shorter and thinner, with more prolateral accessory keels, and an inconspicuous male palpal tibia retrolateral process. Females differ in having a carapace as long as wide. Magnacarina primaverensis sp. nov. has the following character combination: male palpal bulb with a prominent primary projection strongly curved retrolaterally; retroaleteral keel thin and well developed; prolateral superior keel well developed, posterior extension ends almost on the back face of palpal bulb (Fig. 9 A – C); secondary projection with prolateral accessory keels, increasing in size from proximal to distal (Fig. 9 C – D). Prolateral inferior keel wide, increasing from back to front and distal end slightly oriented to apical (Fig. 9 A, C – D). Apical keel well developed, wider in the middle (Fig. 9 D – E). Accessory apophysis barely developed, bearing large megaspines apically (Fig. 8 E). Retrolateral nodule of megaspines with large spines, stout at base and slendering apically (Fig. 8 I). Spermatheca reduced, low, with one single receptacle variable in shape, and strongly sclerotized. Uterus externus that is wider, and four to five times longer than the spermatheca (Fig. 11 A – D). Etymology The specific epithet is a combination of the noun referring to the area that the species inhabits, “Bosque de la Primavera”, and the Latin suffix - ensis, which means “of or from a place”. Type material Holotype MEXICO: ♂, Jalisco, Zapopan, Bosque de la Primavera, 10 Oct. 2012, coll. R. Orozco (CNAN-T0995). Paratypes MEXICO: 4 ♀♀, 1 ♂, Jalisco, Zapopan, Bosque de la Primavera, 20 Aug. 2010, coll. J. Mendoza (females: CNAN-T0996, CNAN-T0999, CNAN-T1000 and CNAN-T1001; male: CNAN-T0998); 1 ♂, Jalisco, Zapopan, Carr. A Colotlán, casi llegando a Huaxtla, Oct. 2013, coll. G. Vila. (CNAN-T0997); 1 ♂, Jalisco, Zapopan, Bosque de la Primavera, 21 Sep. 2013, coll. J. Mendoza (NHM). Description Holotype male CNAN-T0995 (Figs 8–9, 12 A) Body length (not including chelicerae and spinnerets) 16.39, carapace: 7.48 long, 6.44 wide. Caput not markedly elevated; fovea straight, 1.00 wide. Carapace with orange sheen setae and dark cephalic area (Fig. 8 A). Eyes: anterior eye row procurved, posterior eye row, recurved. Eyes sizes and interocular distances: AME 0.325; ALE 0.275; PME 0.20; PLE 0.25; AME – AME 0.15; AME –ALE 0.05; PME– PME 0.50; PME–PLE 0.025; ALE–PLE 0.075. Ocular tubercle, width 1.05; length 0.875; clypeus 0.075 (Fig. 8 D). Labium: length 0.5; width 1.30; with 72 cuspules. Maxilla inner corner with approximately 136-133 (left-right). Cheliceral promargin with 8-8 (left-right) teeth. Sternum length 3.35. Sigilla circular, only third pair hardly visible; posterior sigilla one and half times its length from the margin (Fig. 8 B). Leg formula: IV> I> III> II. Length of legs and palpal segments (femur, patella, tibia, metatarsus, tarsus, total): I: 6.69, 3.46, 4.58, 4.71, 3.61, 23.05; II: 5.48, 3.25, 3.66, 4.37, 3.34, 20.1; III: 4.87, 3.09, 3.67, 4.97, 3.55, 20.15; IV: 6.40, 3.13, 5.47, 7.34, 4.28, 26.62. Palp: 4.25, 2.97, 3.75, -, 2.05, 13.02. Spinnerets: PMS, 1.03 long, 0.43 apart; PLS, 1.60 basal, 1.00 middle, 1.27 distal. Tarsi I–IV scopulate, II and III divided by narrow band of setae, IV divided by strong band of setae. Metatarsi I densely scopulate; II scopulate on distal two thirds, III scopulate on distal half and IV scopulate on distal third. Tibia I with three apophyses. Prolateral apophysis with one short and stout inner spine shorter than its length (Fig. 8 F). Retrolateral apophysis normally developed, slender and slightly curved to dorsal (Fig. 8 E). Accessory apophysis barely developed, bearing five large megaspines at its apex (Fig. 8 E). Metatarsus I curved (Fig. 8 H), with retrolateral megaspines nodule with 14 large spines, stout at base and tapering apically (Fig. 8 I). Retrolateral face of palpal tibiae with a short process, poorly developed on distal third (Fig. 8 G). Chaetotaxy (left side): femora I 1 p; II 1 p; III 1 p, 1r; IV 1 r; palp 1p; patellae none; tibiae I 1 p, 4v; II 2 p, 5v; III 2 p, 5v, 2r; IV 5v, 2r; palp none; metatarsi: I 1v; II 1 p, 7v; III 4 p, 7v, 2r; IV 3 p, 7v, 2r. Palpal bulb with a prominent primary projection strongly curved retrolaterally with distal half twisted to apical. Retrolateral keel thin and well developed. Prolateral superior keel well developed, posterior extension ends almost on the back face of palpal bulb (Fig. 9 A – B, E). Secondary projection short and wide, with three to six prolateral accessory keels well developed increasing in size from proximal to distal (Fig. 9 C – D). Prolateral inferior keel wide, increasing from back to front, distal end slightly oriented to apical (Fig. 9 A, C – D). Apical keel well developed, wider in the middle, covering the sperm pore which opens towards prolateral face (Fig. 9 E). Tegular apophysis slightly developed (Fig. 9 A – B). Urticating setae of type III arranged in one dorsomedian patch, with copper metallic iridescence (Fig. 8 C, 12 A). Variations summarized in Table 2. Color pattern: In live specimens, carapace slightly orange with black cephalic area; ventral coxae, labium, maxillae and sternum dark brown; abdomen dorsally black with reddish setae and dorsomedian patch of copper-colored urticating setae, ventrally black. Legs and palps: femur with dark blue iridescence, patellae orange, tibiae, metatarsi and tarsi black (Fig. 12 A). Paratype female CNAN-T0996 (Figs 10, 11 A, 12 B) Body length (not including chelicerae and spinnerets) 26.67, carapace: 11.82 long, 10.16 wide. Caput not markedly elevated; fovea straight, 2.10 wide. Carapace with orange sheen setae and dark cephalic area (Fig. 10 A). Eyes: anterior eye row procurved, posterior eye row recurved. Eyes sizes and interocular distances: AME: 0.325; ALE: 0.525; PME: 0.325; PLE: 0.325; AME – AME: 0.30; AME –ALE: 0.15; PME–PME: 0.825; PME–PLE: 0.075; ALE–PLE: 0.225. Ocular tubercle, width 1.85; length 1.30; clypeus 0.2 (Fig. 10 D). Labium: length 1.3; width 2.15; with 35 cuspules. Maxilla inner corner with approximately 162-152 (leftright) (Fig. 10 E). Cheliceral promargin with 10-10 (left-right) teeth. Sternum length 5.20. Sigilla oval, first to third pairs hardly visible; posterior sigilla one and half times its length from the margin (Fig. 10 C, F). Leg formula: IV> I> II> III. Length of legs and palpal segments (femur, patella, tibia, metatarsus, tarsus, total): I: 8.03, 5.13, 5.62, 4.60, 3.46, 26.84; II: 6.98, 4.50, 4.83, 4.59, 3.16, 24.06; III: 6.38, 3.81, 4.48, 5.42, 3.58, 23.67; IV: 8.26, 4.26, 5.66, 7.83, 4.63, 30.64. Palp: 6.17, 3.67, 3.90, -, 3.51, 17.25. Spinnerets: PMS, 1.07 long, 0.33 apart; PLS, 2.27 basal, 1.40 middle, 2.3 distal. Tarsi I–IV scopulate, II and III divided by narrow band of setae, IV divided by strong band of setae. Metatarsi I densely scopulate; II scopulate on distal two thirds, III scopulate on distal half, and IV scopulate on distal third. Chaetotaxy (left side): femora II 1 p; III 1 p, 1r; palp 1p; patellae none; tibiae II 1 p, 2v; III 2 p, 4v, 2r; IV 4v, 2r; palp 5v; metatarsi I 1v; II 5v; III 4 p, 6v, 2r; IV 3 p, 8v, 2r. Spermatheca reduced, low with one single semicircular receptacle, strongly sclerotized. Uterus externus is twice wider, and five times longer than the spermatheca (Fig. 11 A). Variation: spermatheca medially longer. Also can be lower but twice wider than normally seen (Fig. 11 B – D). Urticating setae of type III, arranged in one dorsomedian patch, with copper metallic iridescence (Fig. 10 B, 12 B). Variations summarized in Table 2. Color pattern: In live specimens, carapace slightly orange with black cephalic area; ventral coxae, labium, maxillae and sternum dark brown; abdomen dorsally black with reddish setae and dorsomedian patch of copper-colored urticating hairs, ventrally black. Legs and palps: femur with dark blue iridescence, patellae orange, tibiae, metatarsi and tarsi black (Fig. 12 B). Color pattern Color pattern of these spiders changes during their development. Spiderlings of M. primaverensis sp. nov. have a black carapace; the abdomen dorsum is dark with a central patch of urticating hairs. All the femora are black; patellae, tibia, metatarsi and tarsi are orange in color (2nd to 6th instar). In larger stadia, the carapace is dark brown with larger black cephalic area; the rest of the body remains as spiderling color (7th to 8th instar). As the individuals grow, the carapace becomes orange with black cephalic area; the abdomen dorsum develops a few red setae; palps and legs show dark blue iridescent color on femora, patellae becomes orange in color; and tibiae, metatarsi and tarsi become black (9th instar onwards). This last coloration is stronger in adults, especially in males. Recently molted specimens have more vivid colors as observed in other theraphosids. In pre-molting individuals, colors are more opaque. Distribution and natural history Known only from the Natural Protected Area “Bosque de la Primavera”, near Jalisco, México (Fig. 16). All the spiders were found during daytime in a primary forest protected area. They live under rocks in shallow scrapes. The spiders are more difficult to find during the dry season. One of the females was found with a group of 25 spiderlings, with a legspan of 2.5 cm, suggesting that the spiderlings remain with the mother for a few months (Fig. 12 C – D). Since there were no systematic collecting efforts to estimate the size of the population, the density of the distribution cannot be ascertained. The area is under increasing pressure from human activities of the nearby city of Guadalajara, and it is possible that the only existing population is in the protected area of “Bosque de la Primavera”.