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A protonymph of the snout mite genus Odontoscirus Thor, 1913, O. cretacico sp. nov., is described and illustrated from Cretaceous amber of Myanmar is described and illustrated, constituting the earliest fossil species described of the family Bdellidae (ca. 99 Ma). After reexamining the literature and recollected specimens from type localities, we conclude that the following five recent species do not belong to the genus Biscirus and should be transferred to Odontoscirus: O. anomalicornis (Berlese 1916) comb. nov., O. symmetricus (Kramer 1898) comb. nov., O. uncinatus (Kramer 1898) comb. nov., O. norvegicus (Thor 1905) comb. nov., and O. insularis (Willmann 1939) comb. nov. The implications of the fossil record of the family is discussed.

Psilodercidae contains some 200 known extant species of small spiders that live in tropical rainforests and caves and is mainly restricted to the Oriental biogeographic realm. Interestingly, at least ten different fossil species have been described from inclusions in Upper Cretaceous Burmese amber. This suggests the family has been diversifying in the region for at least ~100 million years. In this paper, we revise the taxonomy of fossil species of this family and the closely related Ochyroceratidae, based on the re-examination of type specimens of described species. We find that ten Cretaceous species described in the psilodercid genera Priscaleclercera and Aculeatosoma are valid, and present new illustrations of their type material. The genus Propterpsiloderces apparently does not belong to Psilodercidae, but rather to a family representing a stem lineage within Scytodoidea. Ochyroceratidae is represented in the fossil record by a single ochyroceratine genus from Miocene Dominican amber, Arachnolithulus. The original combination of the extant species Leclercera spinata Deeleman-Reinhold, 1995 is reinstated by transferring it from Priscaleclercera, leaving this latter genus as a strictly fossil taxon. Finally, we present the description of a hitherto unknown species of Priscaleclercera from mid-Cretaceous Burmese amber, Priscaleclercera christae sp. nov., bringing the total number of congeners to ten. By studying its morphological features, we argue that Priscaleclercera is a crown-group Psilodercidae, closely related to the Althepus–Leclercera lineage. The high species diversity of Priscaleclercera indicates that Psilodercidae was already a diverse component of the Oriental tropical forests during the Cretaceous.

Descriptions of defensive behaviors used by Neotropical harvestmen are rarely based upon direct observations of encounters between individuals and syntopic predators. In this study, we investigated the defensive responses exhibited by five harvestman species from Costa Rica in interactions with ctenid spiders (Cupiennius spp.), whip spiders (Phrynus pseudoparvulus), onychophorans (Epiperipatus sp.), and centipedes (Scolopendra sp.). We also observed interactions between harvestmen and a non-predatory invertebrate, the millipede Nyssodesmus python. In 64 encounters, ctenid spiders consumed 11 harvestmen, including eight Prionostemma sp., two Cynorta marginalis, and one Eupoecilaema magnum. The most frequent defensive behavior exhibited by harvestmen was fleeing. Other behaviors included aggression (striking with leg II), bobbing, leg autotomy, lying flat, and thanatosis. Prionostemma exhibited the most variable responses, especially in the presence of ctenid spiders. In addition to the lab-based e...

Relatively little is known about factors that contribute to microhabitat selection among Central American harvestmen. In this study, we compared walking and climbing speeds for five common species from Costa Rica representing the families Cosmetidae (3 species), Gonyleptidae (1 species) and Sclerosomatidae (1 species). Our sample included two arboreal species, two species that infrequently occupy perches in the vegetation, and one species that rarely climbs. Our analyses revealed no significant interspecific differences in climbing speed, although species with relatively long legs walked significantly faster than species with shorter legs. An arboreal habit did not correlate with increased climbing speed, and all species walked significantly faster than they climbed.

In tropical rain forests, harvestmen assemblages are extremely diverse, with richness often exceeding 25 species. In the neotropics, there are published accounts of harvestmen faunas in South America rainforests (especially Amazonia), but relatively little is known about the community ecology of harvestmen in tropical forests of Central America. In this paper, we provide the first insights into the diverse assemblage of harvestmen inhabiting a wet forest at La Selva Biological Station, Costa Rica. Over five field seasons, we recorded 38 species. During our 2009 field season, we examined variation in species abundance, richness, and composition between adjacent successional forests (young secondary, mature secondary, and primary forests) as well as between distinct habitats (ground/litter layer and shrub/tree layer). Based on night samples (but not day), our results indicate that there are only minor differences in species composition and relative abundance between the forest ages, but no differences in richness. The ground/litter layer and shrub/tree layer habitats differed markedly in species composition, species richness, and relative abundance of several species. Our analysis of covariance supports the hypothesis that leg length is related to climbing behavior for several species belonging to Eupnoi and Laniatores.

In encounters with predators, sclerosomatid harvestmen may employ a variety of defensive tactics including the voluntary detachment of legs (autotomy). The long-term costs of this evasive defense are not fully understood, but prior studies have documented negative consequences for terrestrial locomotion and foraging. In this study, we investigated the impact of leg loss upon locomotion in adult harvestmen (Leiobunum spp.). In southeastern Virginia, these harvestmen regularly climb vegetation and occupy perches on tree trunks, branches, and leaves that are often 1–2 m or more above the ground. In our study, we measured walking and climbing speeds for individuals with 5, 6, 7, and 8 legs. The results of our field surveys conducted over three seasons revealed relatively high frequencies (36–63%) of leg loss. We also found that individuals with six legs occupied perches that were significantly lower in the understory than those with eight legs. In the lab, we observed significantly slower walking spe...

Natural history studies serve as important foundations for future investigations of behavioral ecology and provide biologists with critical information needed for the development of empirical research programs. Relatively little is known about the biology of most species of Neotropical harvestmen in Central America. In this field study, we investigated the activity patterns of two common species Cynorta marginalis (Cosmetidae) and Prionostemma sp. (Sclerosomatidae) in a wet tropical forest in Costa Rica. We used visual encounter surveys along randomly selected transects to compare the relative abundance of these species during morning, afternoon, evening, and late night sampling periods. To generate ethograms, we observed up to three individuals of each species for 10 min along each transect, generating 69 behavioral observations for C. marginalis and 51 for Prionostemma. Both species occupy perches on vegetation and are generally nocturnal with respect to activity. After dusk, individuals of C. marginalis actively climb, interact with conspecifics, and forage on the surfaces of small and large trees. During the day, adult Prionostemma form relatively inactive clusters of up to 40 individuals on arboreal perches and descend to the leaf litter after dusk to forage.

In Central America, the family Manaosbiidae is recorded only from Panama and Costa Rica. Four species occur in this region: Barrona williamsi Goodnight & Goodnight 1942, Bugabitia triacantha Roewer 1915, Poassa limbata Roewer 1943, and Zygopachylus albomarginis Chamberlin 1925. In this paper, we describe Barrona felgenhaueri new species (Cocle Province, Panama) and Bugabitia akini new species (Cocle Province, Panama) and report a new record for B. williamsi (Cocle Province, Panama). We used SEM to examine the penis morphology of Barrona Goodnight & Goodnight 1942 and the Caribbean species Cranellus montgomeryi Goodnight & Goodnight 1947 and Rhopalocranaus albilineatus Roewer 1932. We compared genital morphology of these species with published descriptions for Manaosbiidae from South America. With respect to genital morphology, we found that the most variable characters were the number and relative sizes of the setae that occur on the lateral margins of the ventral plate. Other features that exhib...

In July and August 2005, we investigated the use of two distinct microhabitats by harvestmen (Arachnida: Opiliones) in crappo-cocorite seasonal forest, lower montane rain forest, and upper montane rain forest of the Northern Range of Trinidad, West Indies. In addition to new locality records, geographic distributions, and microhabitat use, this article provides a preliminary understanding of the species diversity, compositional similarity, and relative harvestmen abundance among forest stands located within three types of rain forest of different altitudes found in Trinidad. We collected harvestmen inhabiting the space within and underneath decaying logs as well as the leaf litter associated with the logs. In upper montane rain forest, in addition to logs, we sampled the sheaths of palm (Euterpe broadwayi Becc. ex Broadway) fronds, another shelter commonly used by harvestmen that was especially abundant at the higher elevations. We collected 173 individuals representing eight families and 14 species. The number of harvestmen per shelter varied from 3.2 individuals per log in crappo-cocorite forest to 0.8 individual per log or palm frond sheath in upper montane rain forest. In the crappo-cocorite seasonal forest, cosmetids, sclerosomatids and stygnids were most abundant. In upper montane rain forest, cranaids and manaosbiids were the most abundant taxa, whereas cosmetids and sclerosomatids were relatively rare. Crappo-cocorite and lower montane forests were very similar in species composition but differed greatly from upper montane forest. The cosmetids Paecilaema ingleiGoodnight and Goodnight 1947, Cynortula granulata Roewer 1912, and the stygnid Stygnoplus clavotibialis (Goodnight and Goodnight 1947) were found to be strongly correlated with the crappo-cocorite and lower montane forests, whereas in upper montane forests Santinezia serratotibialisRoewer 1932 and Cranellus montgomeryiGoodnight and Goodnight 1947 were closely correlated.

Larval erythraeid mites are common ectoparasites of harvestmen (Opiliones). However, interactions between these mites and hosts in tropical environments have received little attention. In this study, we examined the prevalence and intensity of mite infestations for Neotropical harvestmen from the Caribbean island of Trinidad. Overall, the prevalence of infestation was 9.9%, with significant interspecific variation in the intensity of mite infestation and significant differences in parasitism of hosts between habitats. Harvestmen collected from lowland, crappo-cocorite forest exhibited the highest infestation rates. In our samples, the intensity of infestation varied from 1 to 17 mites per host. Examination by scanning electron microscopy revealed that harvestmen were infested by two taxa of mites, a species of Leptus and another unidentified erythraeid species. Our observations represent the first host records for erythraeid mites parasitizing harvestmen from the families Cranaidae and Manaosbiidae. Mites were found to attach preferentially to the tibia and femur of the leg (175 of 178 observations). In general, the harvestmen of Trinidad exhibited mite parasitism in a fashion similar to temperate species with respect to site of attachment and prevalence and intensity of mite infestation. In the field, we also collected an adult Cynortula sp. (Cosmetidae) that was transporting 30 gravid adults of an oribatid mite (Acariformes, Oribatida, Mixonomata). Cases of mite phoresy upon harvestmen are rare, with our observation representing the first report of phoresy by an oribatid mite upon a harvestman and the first documentation of mite phoresy upon harvestmen in the Caribbean.

A new troglobitic harvestman, Relictopiolus galadriel gen. nov et sp. nov., is described from Olhos d’Água cave, Itacarambi, Minas Gerais State, Brazil. Morphological characters, including male genitalia and exomorphology, suggest that this species belongs to the family Kimulidae, and it appears to share the greatest similarities with Tegipiolus pachypus. Bayesian inference analyses of a molecular dataset strongly support the inclusion of this species in Kimulidae and confirm the hypothesized sister-group relationship between R. galadriel and T. pachypus. A time calibrated phylogeny indicates that these sister-taxa diverged from a common ancestor approximately 40 Mya, during the Paleogene. The current range of Kimulidae illustrates a remarkable disjunct distribution, and leads us to hypothesize that the ancestral distribution of Kimulidae was once much more widespread across eastern Brazil. This may be attributed to the Eocene radiation associated with the warming (and humidifying) events in the Cenozoic when the best conditions for evergreen tropical vegetation in South America were established and followed by the extinction of kimulid epigean populations together with the retraction of rain forests during the Oligocene to Miocene cooling. The discovery of this relictual troglobite indicates that the Olhos d’Água cave was a stable refugium for this ancient lineage of kimulids and acted as a "museum" of biodiversity. Our findings, considered collectively with the diverse troglofauna of the Olhos d’Água cave, highlight it as one of the most important hotspots of troglobite diversity and endemism in the Neotropics. Given the ecological stresses on this habitat, the cavernicolous fauna are at risk of extinction and we emphasize the urgent need for appropriate conservation actions. Finally, we propose the transfer of Acanthominua, Euminua, Euminuoides and Pseudominua from Kimulidae to Zalmoxidae, resulting in two new synonymies and 13 new combinations. Fil: Pérez González, Abel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Ceccarelli, Fadia Sara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Monte, Bruno G. O.. Universidade Federal do São Carlos; Brasil Fil: Proud, Daniel Nathan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: DaSilva, Márcio Bernardino. Universidade Federal da Paraíba; Brasil Fil: Bichuette, Maria E.. Universidade Federal do São Carlos; Brasil

Although relatively rare among harvestmen in the superfamily Gonyleptoidea, paternal care has been observed in the families Manaosbiidae and Gonyleptidae, but not previously in the Cosmetidae. In this study, we describe multiple observations of egg guarding by adult males of an undescribed species of cosmetid harvestman from Volcan Cacao, Guanacaste Province, Costa Rica. Observations were made from 26–28 July 2010, during the wet season. In this species, males only guard eggs after dusk, leaving eggs unattended during the day. Based upon differences in color and size, males guarded eggs through several stages of development. When guarding, males contacted the first two pairs of legs with the eggs. Oviposition sites consisted of the undersides of leaves of small plants, with eggs closely packed together in a single layer covered by abundant, transparent mucus. The largest, darkest eggs were located near the distal tip of the leaf.

Parental care in harvestmen may take several forms including egg hiding, egg guarding, egg transport and young guarding. In most species, one adult, usually the female, performs guarding of the young. From 9 July–3 August 2005, we made observations of parental care by adults of the Neotropical cranaid harvestman Phareicranaus calcariferus (Simon 1879) in northern and central Trinidad. Nine observations involved an adult female and young while three appeared to include both an adult female and male with young. The number of young present was inversely related to the size of the young, indicating that parental care in this species may occur over an extended period of time.