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The knowledge of arachnofauna from Tocantins, Brazil, is still incipient. The present communication expands the known geographical distribution of Loxosceles amazonica Gertsch, 1967 (Arachnida: Araneae: Sicariidae) in Brazilian Cerrado. The brown spider specimens were sampled in Dianópolis municipality and Cristalândia municipality both in Tocantins State, Brazil, between 2022 and 2024. Also, we describe a new variation of the epigynum of L. amazonica. Mapping the distribution of Loxosceles Heineken & Lowe, 1832 species in Brazil is crucial for public health, aiding in prevention and timely treatment of loxoscelism caused by brown spider bites.

The family Orsolobidae Cooke, 1965, is newly recorded for Uruguay, with the first record of Losdolobus nelsoni Pompozzi, 2015, a recently described species that is endemic to the Buenos Aires Province, Argentina, and herein recorded in the Rocha and Montevideo departments. The biogeographic implications of this record are commented on and some data on the phenology of the species are presented. [ABSTRACT FROM AUTHOR]

Species of the spider family Telemidae Fage, 1913 from East and Southeast Asia are revised. Four new genera are erected: Mekonglema Zhao & Li, gen. nov. with the type species Mekonglema bailang Zhao & Li, sp. nov. (♂♀, Yunnan, China), Siamlema Zhao & Li, gen. nov. with the type species Siamlema changhai Zhao & Li, sp. nov. (♂♀, southern Thailand), Sundalema Zhao & Li, gen. nov. with the type species Sundalema bonjol Zhao & Li, sp. nov. (♂♀, Sumatra), and Zhuanlema Zhao & Li, gen. nov. with the type species Zhuanlema peteri Zhao & Li, sp. nov. (♂♀, northern Laos). Eight additional new species are described: Mekonglema kaorao Zhao & Li, sp. nov. (♂♀, northern Laos), M. walayaku Zhao & Li, sp. nov. (♂♀, Yunnan, China), M. yan Zhao & Li, sp. nov. (♂♀, Yunnan, China), Pinelema daguaiwan Zhao & Li, sp. nov. (♂♀, Guangxi, China), P. shiba Zhao & Li, sp. nov. (♂♀, Guangxi, China), P. tham Zhao & Li, sp. nov. (♂♀, northern Laos), Siamlema suea Zhao & Li, sp. nov. (♂♀, southern Thailand), and Sundalema khaorakkiat Zhao & Li, sp. nov. (♂♀, southern Thailand). Thirty species are transferred from the genus Telema Simon, 1882 to the genera Pinelema Wang & Li, 2012, Sundalema gen. nov., and Telemofila Wunderlich, 1995. Seychellia xinpingi Lin & Li, 2008 is transferred to Mekonglema gen. nov. as M. xinpingi comb. nov. Furthermore, the genus Pinelema is divided into seven species groups based on male morphological characters. [ABSTRACT FROM AUTHOR]

The spinning apparatus and silk of Segestria senoculata were studied with the use of scanning electron microscopy and light microscopy, which confirmed the presence of four categories of spigots connected with four types of spinning glands (i.e., Glandulae ampullaceae major, Glandulae ampullaceae minor, Glandulae piriformes and Glandulae pseudaciniformes). New data about the morphology of spinnerets and spigots were obtained for both the adults and nymphal stages of both sexes. For the first time the silken threads of retreats, signal threads and attachment discs of the members of Segestria were subjected to a detailed SEM study. The data resulting from studying the spinning apparatus of S. senoculata was compared to current knowledge of the silk producing systems of families belonging to the Dysderoidea superfamily. Silks that are emitted from spigots in the course of retreat construction are not (similarly to the other dysderoids) processed by the spider’s legs during the subsequent process of hardening. Apart from the major ampullate glands/spigots, segestriids also possess developed minor ampullate glands. Minor ampullate threads are used by S. senoculata spiders when making their signal threads.

The described Afrotropical species of the genus Hexophthalma Karsch, 1879 (under the genus name Sicarius Walckenaer, 1847), of the spider family Sicariidae Keyserling, 1880, were recently reviewed. In the present paper the Afrotropical species of the genus Hexophthalma are revisited. After a thorough examination of all the available specimens from nine major collections, the species H. testacea (Purcell, 1908) is here synonymized with H. hahni (Karsch, 1878), three new species are described – H. binfordae sp. nov., H. goanikontesensis sp. nov. (both from Namibia) and H. leroyi sp. nov. (from South Africa) – and the male of H. dolichocephala (Lawrence, 1928) is described for the first time. The distribution of the species is also revised and a new updated key to the species is compiled.

The redescription of dysderid spider Harpactea korgei Brignoli, 1979, on the basis of newly collected material is provided. The female of this species, previously unknown, is described here for the first time.

The family Tetrablemmidae O. Pickard-Cambridge, 1873 is reported from Cambodia for the first time. Two species belonging to the genus Tetrablemma O. Pickard-Cambridge, 1873 are documented as new to science: Tetrablemma kepense sp. n. (male, female) from Kep Province and Tetrablemma sokense sp. n. (male, female) from Battambang Province. Diagnoses, morphological descriptions, and comparative illustrations are provided. [ABSTRACT FROM AUTHOR]

Loxosceles Heineken & Lowe, 1832 spiders are infamous for their medical importance, but a taxonomic picture of the genus is still far from complete. In this study, the Chilean species of Loxosceles are described and mapped. The males of Loxosceles surca Gertsch, 1967 and L. coquimbo Gertsch, 1967 are described for the first time. Three new species with narrow distributions are described from central and northern Chile: Loxosceles diaguita sp. nov. from the Antofagasta Region, L. pallalla sp. nov. from Coquimbo and L. vallenar sp. nov. from Atacama. The first two species are remarkable in their morphology and do not fit into any of Gertsch’s species groups, suggesting that Chile still harbours an undiscovered phylogenetic diversity of the genus. New distribution records for Loxosceles laeta (Nicolet, 1849) are provided throughout Chile.

Loxosceles rufescens, the Mediterranean recluse spider, is a cosmopolitan species with toxic venom which can cause skin lesions (arachnogenic necrosis) in humans. Here, the complete mitochondrial genome (mitogenome) was determined for L. rufescens (Sicariidae). It had a circular mapping organization with 15,210 bp in length containing 13 protein-coding genes, two ribosomal RNA genes, 21 putative transfer RNA genes, and one control region. A Bayesian phylogenomic analysis of the representative species in Araneae showed that L. rufescens had a closer relationship with two species of Pholcidae and one species of Hypochilidae, which were the haplogyne spiders. The complete mitogenome will aid identification of L. rufescens, facilitate further genetic studies of the significant pest, and contribute to spider phylogenetic inferences.

Seven new species of the spider genus Pinelema Wang & Li, 2012, from Vietnam are reported: P. damtaoensis Zhao & Li, sp. n. (♂♀), P. nuocnutensis Zhao & Li, sp. n. (♂♀), P. laensis Zhao & Li, sp. n. (♂♀), P. pacchanensis Zhao & Li, sp. n. (♂♀), P. spirulata Zhao & Li, sp. n. (♂♀), P. xiezi Zhao & Li, sp. n. (♂♀), and P. zhenzhuang Zhao & Li, sp. n. (♂♀). Prior to the current study, this genus contained eight species and was known only from southwestern China. The diagnosis of the genus is updated, accounting for characters found in the new species. [ABSTRACT FROM AUTHOR]

Seven new species of the spider genus Ochyrocera from cave areas in Floresta Nacional de Carajás (state of Pará, northern Brazil) are described: Ochyrocera varys sp. n., Ochyrocera atlachnacha sp. n., Ochyrocera laracna sp. n., Ochyrocera aragogue sp. n., Ochyrocera misspider sp. n., Ochyrocera charlotte sp. n., and Ochyrocera ungoliant sp. n. Two groups of the species are discussed, the quinquivittata group that include specimens with an apparently bifid retrolateral apophysis in the cymbium of the male palp and the arietina group, here proposed, that include those specimens with an entire cymbium, with no retrolateral apophysis, in the male palp. Although these species were abundant inside caves, the examined specimens do not have troglomorphic characteristics and can be classified as edaphic troglophile species, capable of completing its life cycle in soil, shallow subterranean habitats, or caves. [ABSTRACT FROM AUTHOR]

Three new Pinelema species, P. cunfengensis Zhao & Li, sp. n. (♂♀), P. podiensis Zhao & Li, sp. n. (♂♀), and P. qingfengensis Zhao & Li, sp. n. (♂♀), are described from the Guangxi Zhuang Autonomous Region of China, bringing the total number of Pinelema species to eight. All occur in Yunnan Province or the Guangxi Zhuang Autonomous Region. The male palp of Telemidae was studied for the first time using scanning electron microscope. [ABSTRACT FROM AUTHOR]

The male of Oonops nigromaculatus Mello-Leitão 1944 is described for the first time and the female is redescribed from recently collected specimens. New records from Argentina and Uruguay are provided.Se describe por primera vez el macho de Oonops nigromaculatus Mello-Leitão 1944, y la hembra se redescribe sobre la base de nuevos especímenes colectados recientemente. Se proveen nuevos registros de la Argentina y Uruguay.

A new genus and species of tetrablemmid spider, Electroblemma bifida n. gen. et sp., is described, from two adult males found in Upper Cretaceous (Cenomanian) amber of Myanmar. The genus is distinguished by its enormous dorsal carapace projection and highly modified chelicerae. The new genus is referred to the tribe Tetrablemmini within the subfamily Tetrablemminae. The presence of a relatively derived tetrablemmid on the south-east Eurasian continent during the Late Cretaceous suggests that the family was already well diversified in tropical rainforests at this time. [ABSTRACT FROM AUTHOR]

New members of the spider family Caponiidae from Brazil and Chile are presented. Three new species in previously known genera are described: Taintnops paposo sp. n. from Chile, and the Brazilian Tisentnops mineiro sp. n. and Tisentnops onix sp. n., both belonging to a genus known only from its damaged type. Additionally, two new non-+nopine Brazilian genera are proposed: Nasutonops gen. n. including three new species: N. chapeu sp. n., N. sincora sp. n. and N. xaxado sp. n.; and Carajas gen. n., known only from the type species C. paraua sp. n. Both new genera have entire, rather than sub-segmented tarsi. Therefore, they are not included in the caponiid subfamily Nopinae. Nasutonops gen. n. is characterized by the presence of a projected clypeal horn, unique among caponiids. Additionally, the first blind caponiids are described: Tisentnops mineiro sp. n. from the state of Minas Gerais and Carajas paraua sp. n. from the state of Pará. Both of these species are found only in caves and completely lack eyes. [ABSTRACT FROM AUTHOR]

The spinning apparatus and silk of Segestria senoculata were stud-ied with the use of scanning electron microscopy and light microscopy, which confirmed the presence of four categories of spigots connected with four types of spinning glands (i.e., Glandulae ampullaceae major, Glandulae ampullaceae minor, Glandulae piriformes and Glandulae pseudaciniformes). New data about the morphology of spinnerets and spigots were obtained for both the adults and nymphal stages of both sexes. For the first time the silken threads of retreats, signal threads and attachment discs of the members of Segestria were subjected to a detailed SEM study. The data resulting from studying the spinning apparatus of S. senoculata was compared to current knowledge of the silk producing systems of families belonging to the Dysderoidea superfamily. Silks that are emitted from spigots in the course of retreat construction are not (similarly to the other dysderoids) processed by the spider’s legs during the subsequent process of hardening. Apart from the major ampullate glands/spigots, segestriids also possess developed minor ampullate glands. Minor ampullate threads are used by S. senoculata spiders when making their signal threads. [ABSTRACT FROM AUTHOR]

Three new species of the spider genus Leptonetela collected from caves in Greece are described: L. arvanitidisi sp. n. (male & female), L. paragamiani sp. n. (male & female) and L. penevi sp. n. (male & female). Detailed illustrations of the new species are provided. DNA barcodes were obtained for future use. [ABSTRACT FROM AUTHOR]

Two new species of Tangaroa Lehtinen 1967 (Araneae: Uloboridae) from the Cook Islands are described here: Tangaroa vaka n. sp. from Rarotonga, and Tangaroa pukapukan n. sp. from Mitiaro, both based on male and female specimens. [ABSTRACT FROM AUTHOR]

The rates of oxygen consumption and carbon dioxide release of primitive hunters and weaver spiders, the Chilean Recluse spider Loxosceles laeta Nicolet ( Araneae: Sicariidae) and the Chilean Tiger spider Scytodes globula Nicolet ( Araneae: Scytodidae), are analyzed, and their relationship with body mass is studied. The results are compared with the metabolic data available for other spiders. A low metabolic rate is found both for these two species and other primitive hunters and weavers, such as spiders of the families Dysderidae and Plectreuridae. The metabolic rate of this group is lower than in nonprimitive spiders, such as the orb weavers ( Araneae: Araneidae). The results reject the proposition of a general relationship for metabolic rate for all land arthropods (related to body mass) and agree with the hypothesis that metabolic rates are affected not only by sex, reproductive and developmental status, but also by ecology and life style, recognizing here, at least in the araneomorph spiders, a group having low metabolism, comprising the primitive hunters and weaver spiders, and another group comprising the higher metabolic rate web building spiders (e.g. orb weavers). [ABSTRACT FROM AUTHOR]

Four new species of oonopid spiders are described from Madagascar, divided between the genera Silhouettella and Noideattella: S. perismontes, sp. nov., S. perisalma, sp. nov., N. omby, sp. nov., and N. sylvnata, sp. nov. A new diagnosis for Silhouettella is provided, its type species, S. curieusei, from the Seychelles is redescribed, and its morphology thoroughly documented with digital images. [ABSTRACT FROM AUTHOR]

Citharoceps Chamberlin was diagnosed by the presence of a very distinctive stridulatory apparatus composed of two patches of ridges on the sides of the cephalic region, and a stridulatory thorn on the prolateral region of the femur I. Currently, this genus is a junior synonym of Ariadna Audouin, with the assumption that the stridulatory apparatus could constitute an exclusive feature of its unique known species, Citharoceps fidicina Chamberlin, currently senior synonym of Citharoceps californica Chamberlin & Ivie. In the present study, Citharoceps is revalidated and redescribed based on the occurrence of the stridulatory apparatus in C. fidicina and Segestria cruzana Chamberlin & Ivie, and also on the presence of distinguishable characters, such as the length of the labium-sternum junction, ventral median spine on male metatarsi I, and strong sclerotized interpulmonary fold in females, forming a conspicuous median flap. Segestria cruzana is transfered to Citharoceps, with C. californica removed from the synonym of C. fidicina, and proposed as a junior synonym of C. cruzana, due to the similarity between the additional material examined and the original description. Males of C. fidicina and C. cruzana are described for the first time. [ABSTRACT FROM AUTHOR]

Spider genital morphology usually provides the best characters for taxonomy. Furthermore, functional genital morphology helps to understand the evolution of complex genitalia and their role in the context of sexual selection. The genital systems of most haplogyne spider families are poorly investigated with respect to their morphology. The present study investigates the female genitalia of the oonopids Oonops pulcher, Oonopinus kilikus, and Pseudotriaeris sp. by means of light microscopy and SEM. The male palps are briefly described. Females of O. pulcher store spermatozoa in an anterior and a posterior receptaculum (PRe). The genitalia resemble the primitive dysderoid genitalia supporting the hypothesis that the subfamily Oonopinae contains more basal oonopids. In O. kilikus, the anterior receptaculum is reduced to a sclerite. Spermatozoa are stored in a PRe. The receptacula of Pseudotriaeris sp. are reduced to sclerites. Spermatozoa in the uterus internus indicate that fertilization happens there or in the ovary. The anterior sclerite might serve females to lock the uterus during copulation as suggested for other gamasomorphines. The male palp of O. kilikus is simple, whereas the palps of O. pulcher and Pseudotriaeris sp. appear more complex. Complicated structures on the palp of Pseudotriaeris sp. indicate that males exert copulatory courtship. [ABSTRACT FROM AUTHOR]

Scanning electron microscopy and atomic force microscopy were used to study the silk spinning apparatus and silks of Harpactea rubicunda spiders. Three types of silk secretions that are produced by three kinds of silk spinning glands (ampullate, piriform, and pseudaciniform) and released through three types of spigots, were confirmed for both adult and juvenile spiders. Silk secretions for the construction of spider webs for shelter or retreat are produced by the pseudaciniform silk glands. Silk secretions that are released from spigots in the course of web construction are not processed by the legs during the subsequent process of hardening. Pairs of nanofibril bundles seemed to be part of the basic microarchitecture of the web silk fibers as revealed by AFM. These fiber bundles frequently not only overlap one another, but occasionally also interweave. This structural variability may strengthen the spider web. High-resolution AFM scans of individual nanofibrils show a distinctly segmented nanostructure. Each globular segment is ∼30-40 nm long along the longitudinal axis of the fiber, and resembles a nanosegment of artificial fibroin described by Perez-Rigueiro et al. (2007). Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Telema tenella Simon, 1882, the type species of genus Telema, is the only species of family Telemidae reported from Europe and all other 39 congeners occur far from it. However, it has never been properly described. In this paper T. tenella is redescribed and illustrated. [ABSTRACT FROM AUTHOR]

The new spider genus and species Trogloraptor marchingtoni Griswold, Audisio & Ledford is described as the type of the new family Trogloraptoridae. The oblique membranous division of the basal segment of the anterior lateral spinnerets of Trogloraptor suggests that this haplogyne family is the sister group of the other Dysderoidea (Dysderidae, Oonopidae, Orsolobidae and Segestriidae). Trogloraptor is known only from caves and old growth forest understory in the Klamath-Siskiyou region of Oregon and California. [ABSTRACT FROM AUTHOR]

The spider genus Tayshaneta is revised based on results from a three gene phylogenetic analysis (Ledford et al. 2011) and a comprehensive morphological survey using scanning electron (SEM) and compound light microscopy. The morphology and relationships within Tayshaneta are discussed and five species-groups are supported by phylogenetic analyses: the anopica group, the coeca group, the myopica group, the microps group and the sandersi group. Short branch lengths within Tayshaneta contrast sharply with the remaining North American genera and are viewed as evidence for a relatively recent radiation of species. Variation in troglomorphic morphology is discussed and compared to patterns found in other Texas cave invertebrates. Several species previously known as single cave endemics have wider ranges than expected, suggesting that some caves are not isolated habitats but instead form part of interconnected karst networks. Distribution maps are compared with karst faunal regions (KFR's) in Central Texas and the implications for the con-servation and recovery of Tayshaneta species are discussed. Ten new species are described: T. archambaulti sp.n.T. emeraldae sp. n.T. fawcetti sp. n.T. grubbsi sp. n.T. madla sp. n.T. oconnorae sp. n.T. sandersi sp. n. T. sprousei sp. n.T. vidrio sp. n. and T. whitei sp. n. The males for three species, T. anopica (Gertsch,1974), T.devia (Gertsch,1974) and T.microps (Gertsch,1974) are described for the first time. Tayshaneta furtiva (Gertsch, 1974) and T. uvaldea (Gertsch,1974) are declared nomina dubia as the female holotypes are not diagnosable and efforts to locate specimens at the type localities were unsuccessful. All Tayshaneta species are thoroughly illustrated, diagnosed and keyed. Distribution maps are also provided highlighting areas of taxonomic ambiguity in need of additional sampling [ABSTRACT FROM AUTHOR]

The article focuses on a research conducted in order to describe the male genital mutilation in the high-mountain goblin spider Unicorn catleyi. It describes male genital mutilation as a common mechanism by which males reduce sperm competition by combining female insemination ducts with different parts of its own genital system. The study revealed the presence of embolus in the posterior receptaculum as the first place where sperm is received.

Abstract: The genital structures of most spiders are poorly investigated in respect of their functional morphology because the traditional taxonomic practice is to inspect slide-mounted genitalia only. The present study describes the female genitalia of three members belonging to the megadiverse haplogyne spider family Oonopidae by means of histological serial sections, scanning electron microscopy, and X-ray ultramicroscopy. The female genitalia of Neoxyphinus ogloblini, Dysderina sp., and Heteroonops spinimanus are complex and might have evolved under sexual selection by cryptic female choice. However, there is no direct evidence for cryptic female choice in these species based on the results of the present study. In N. ogloblini and Dysderina sp., spermatozoa and secretion are stored in a large receptaculum. Highly elongated gland cells filled with secretory vesicles extend over the receptaculum of N. ogloblini. In addition, sperm are present in the uterus internus of female N. ogloblini and Dysderina sp. The location of fertilization is still unknown for most spiders. One female of Dysderina sp. had sperm in the uterus and ovary strongly suggesting that fertilization in this species takes place in the ovary. An anterior sclerite with attached muscles should serve females to lock the uterus externus during copulation as suggested for other oonopids. The male palp of N. ogloblini shows a simple embolus whereas the embolus of Dysderina sp. is more complicated and accompanied by a cork-screw-shaped conductor. Females of H. spinimanus have an anterior sclerite in which thread-like gland ducts lead. The chitinized posterior diverticulum shows peculiar papillae in its anterior wall. The exact location of sperm storage in H. spinimanus remains unknown since spermatozoa were not present in the anterior sclerite and the posterior diverticulum. The anterior sclerite might be used to lock the uterus externus similar to N. ogloblini and Dysderina sp. H. spinimanus was previously suggested to be parthenogenetic and a male has only been recently associated with this species. The male was not investigated for this study. [Copyright &y& Elsevier]

The karyotypes of several individuals of Dysdera crocata C.L. Koch 1838 (Dysderidae), Ariadna boesenbergi Keyserling 1877, and Segestria ruficeps Guérin 1832 (Segestridae) are described. Diffuse centromeres were observed in the 3 species. D. crocata and A. boesenbergi exhibit chromosome number polymorphism, with the presence of trivalent chromosomes in the first metaphase in some individuals. They also show testicular cysts with polyploid spermatogonia and spermatocytes. The haploid chromosome number for these 2 species varies between n = 3 + X and n = 6 + X. The first meiotic division in D. crocata is equational while the second meiotic division is reductional for trivalents and the X chromosome. The first meiotic division in A. boesenbergi is equational for trivalents, and reductional for the X, while the second division is reductional for hemi-trivalents and equational for the X. In S. ruficeps the haploid chromosome number is n = 6 + X1X2, and the first division is reductional for the Xs. The evolution of karyotypes within haplogyne spiders is discussed in relation to the origin of diffuse centromeres. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: The unusual reproductive biology of many spider species makes them compelling targets for evolutionary investigations. Mating behavior studies combined with genital morphological investigations help to understand complex spider reproductive systems and explain their function in the context of sexual selection. Oonopidae are a diverse spider family comprising a variety of species with complex internal female genitalia. Data on oonopid phylogeny are preliminary and especially studies on their mating behavior are very rare. The present investigation reports on the copulatory behavior of an Orchestina species for the first time. The female genitalia are described by means of serial semi-thin sections and scanning electron microscopy. Females of Orchestina sp. mate with multiple males. On average, copulations last between 15.4 and 23.54min. During copulation, the spiders are in a position taken by most theraphosids and certain members of the subfamily Oonopinae: the male pushes the female back and is situated under her facing the female''s sternum. Males of Orchestina sp. possibly display post-copulatory mate-guarding behavior. The female genitalia are complex. The genital opening leads into the uterus externus from which a single receptaculum emerges. The dorsal wall of the receptaculum forms a sclerite serving as muscle attachment. A sclerotized plate with attached muscles lies in the posterior wall of the uterus externus. The plate might be used to lock the uterus during copulation. The present study gives no direct evidence for cryptic female choice in Orchestina sp. but suggests that sexual selection occurs in the form of sperm competition through sperm mixing. [Copyright &y& Elsevier]

Fine morphological details of the genitalia have large potential consequences for the understanding of the reproductive biology of a particular species, especially when mating behavioral studies are difficult to conduct. Oonopidae are a highly diverse spider family comprising a variety of species with complex female reproductive systems, which may have evolved under sexual selection by cryptic female choice. The present study describes the female genitalia of five oonopid species belonging to both conventionally recognized subfamilies by means of semi-thin sections and scanning electron microscopy. In addition, the male palps are briefly described. The organization of the female genitalia in Scaphiella hespera and Scaphiella sp. resembles the entelegyne type. A chitinized canal connects the receptaculum, where sperm are stored, with the uterus. Sperm are also present in the uterus and the canal is suggested to function as fertilization duct. The genitalia of the parthenogenetic species Triaeris stenaspis are surprisingly complex. A large sac with glands is proposed to represent the equivalent of a receptaculum in sexually reproducing females. In females of Opopaea recondita, sperm are stored in a bulge derivating from the uterus. Contractions of muscles attached to the bulge may lead to sperm dumping. The uterus can be closed by a sclerite in its anterior wall. The receptacula of females of Stenoonops reductus are joined together and contain masses of spermatozoa. Additional sperm were found in the receptacula connection suggesting that fertilization takes place there. The male palps of all the investigated species, except for S. hespera, seem to lack a distincly sclerotized sperm duct. Spermatozoa and secretions are stored in a large reservoir inside the genital bulb surrounded by glandular epithelium. [ABSTRACT FROM AUTHOR]

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

Pholcidae is the most diverse family among haplogyne spiders but only 15 species have been analyzed cytogenefically. These studies revealed that the diploid number varies from 2n = 15 to 2n = 32, that there are three types of sex chromosome systems in males (X, X1X2 and X1X2Y), and that the chromosomes are predominantly biarmed. Within the genus Mesabolivar, only Mesabolivar luteus (Keyserling 1891) has been karyotyped, and it showed 2n = 15 = 14 + X, with all chromosomes being metacentric. In the present work, we characterize the mitotic and meiotic chromosomes of Mesabolivar brasiliensis (Moenkhaus 1898) and Mesabolivar cyaneotaeniatus (Keyserling 1891). Male mitotic mctaphases of the two species showed the diploid number 2n = 17 = 16 + X; oogonial cells of M. brasiliensis showed 2n = 18 = 16 + XX. In both species, the chromosomes were exclusively biarmed, and the X chromosome was the largest element of the karyotype. Diplotene spermatoeytes of the two species exhibited 811 + X and the occurrence of only one terminal or interstitial chiasma per bivalent. In M, cyaneotaeniaus, metaphases II with n = 9 = 8 + X and n = 8 were found, indicating the regular segregation of all chromosomes during meiosis L Mitotic metaphases of M. brasiliensis stained with CMA3DA/ DAPI revealed GC-rich chromatin in the terminal region of almost all autosomes, especially in pair 2. An earlier revision of the New World pholcids grouped M. brasillensis and M. cyaneotaeniatus in a "southern group" and placed M. luteus in a "miscellaneous group." A molecular study showed a closer relationship between M. brasiliensis and M. cyaneotaeniatus than between M. luteus and either of these two species. The 2n = 17 found in M. brasiliensis and M. cyaneotaeniatus corroborates this hypothesis, given that M. luteus has a diploid number of 2n = 15. [ABSTRACT FROM AUTHOR]

The present study shows that females of Silhouettella loricatula (Arachnida: Araneae: Oonopidae) manage to process sperm in an unusual and previously unknown way. The male ejaculate consisting of spermatozoa and globular secretion is enclosed in a secretory sac. This may avoid the mixing of sperm from different males and at least severely limit sperm competition. The process of sperm enclosure occurs within the female's sperm storage site (receptaculum) as the ejaculate is not surrounded by a sac inside the male's sperm-transferring organs (palpal bulbs). The secretion forming the sac is produced by glands adjoining the receptaculum. The possibility that globular secretions in the male palpal bulbs partly contribute to the sac cannot be ruled out completely. It is suggested that in S. loricatula, the main function of sperm enclosure in a sac is enabling females to dump the ejaculate of a male. The present study represents the first report on sperm dumping in the family Oonopidae. During five first and three second copulations in the laboratory, the dumping of a sac was observed. One dumped sac was sectioned and contained spermatozoa. Two couples were flash-fixed with liquid nitrogen early during copulation, which revealed the mechanism of the sac dumping. By muscle contractions, the receptaculum is bent backwards and the sac moved into the genital opening. The actual sac dumping occurs most probably in cooperation with the male, which moves his pedipalps rhythmically during the entire copulation. Extensions and furrows on the emboli suggest that they may additionally be used as copulatory courtship devices. The enclosure of sperm from the current male in secretion takes place during or immediately following copulation as all mated females sacrificed after copulation had a new sac containing spermatozoa in the receptaculum. Dumping sperm of a previous male during the next copulation may allow females to bias sperm precedence. [ABSTRACT FROM AUTHOR]

The spider family Oonopidae is described from Cretaceous ambers from Myanmar and Canada for the first time. Orchestina albertenis sp. nov. is the first spider to be described from Canadian Grassy Lake amber and only the second spider to be described from Canadian amber. The specimen in amber from Myanmar extends the known range of the extant genus Orchestina back another 10 million years from the previously oldest specimen in Turonian New Jersey amber. Despite being unknown as sedimentary fossils, Oonopidae occur in more fossil deposits than any other spider family and were already widespread by the Cretaceous. The family contains the oldest example of an extant spider genus along with Archaeidae, also from Burmese amber. [ABSTRACT FROM AUTHOR]