Although Mesobuthus scorpions in China have become endangered in recent years, they are largely underinvestigated. Even the baseline data on their distributions are lacking. Here the geographical distributions of two Mesobuthus scorpions in China are provided through a combined study of systematic field surveys and GIS-based ecological niche modeling using 227 surveyed point occurrence data across an area of ca. 2800 × 1700 km² and validated historical records. Mesobuthus martensii (Karsch 1879) appears to be restricted to latitude south of 43°N and the north side of the Yangtze River, bordered by the Helan Mountains and the Tengger and Mo Us sand desert in the west and limited by the sea in the east. Mesobuthus eupeus (C.L. Koch 1839) reaches the east side of the Helan Mountains and the west edge of the Loess Plateau, extending westward along the northern slope of the Qilian Mountains and ultimately penetrating to the northern part of the Junggar Basin. The former is mainly found in semi-humid and humid regions while the latter is an arid and semi-arid dweller. The two species show a parapatric distribution on the whole with a contact zone formed at the boundary of their ranges across the big turning of the Yellow River in the central-western part of Inner Mongolia, Ningxia and the middle part of the Gansu Province. This pattern of distribution is shaped both by the fundamental ecological niche constraint of the species and possibly by the biological interactions between the two species. Some diagnostic features for the two species are also provided for quick identification.

Species of Polybetes are known exclusively from South America. Currently there are 13 described species, 9 occurring in Argentina. Cytogenetic studies in spiders are scarce; the cytogenetics of only about 1% of nearly 39,500 described species are known. Within the Sparassidae, 38 species out of 1,009 (< 4%) have been cytogenetically analyzed; the most frequent chromosome number is 2n = 43/46 (male/female), n = 20 X₁X₂X₃, present in almost half of the species studied. Female diploid chromosome number is only known for four species: Heteropoda venatoria (Linnaeus 1767) (2n = 44); Pediana regina (L. Koch 1875), Isopeda sp. and Olios sp. (2n = 46). Within the genus Polybetes, only P. pythagoricus (Holmberg 1875) had been previuosly cytogenetically analyzed. In the present work, the karyotype, heterochromatin content and distribution, and silver stained nucleolus-organizer regions of P. pythagoricus, P. rapidus (Keyserling 1880) and P. punctulatus Mello-Leitão 1944 are described and compared. In P. pythagoricus the identification of the chromosome pairs by means of G-banding is also performed. Females of the three species show a chromosome complement of 44 telocentric chromosomes, with a similar karyotype. Males of P. pythagoricus show 42 telocentric chromosomes, the two sex chromosomes being the largest and of different size. In the three species, two pairs of telomeric NORs and small pericentromeric positive C-bands in all chromosomes were detected. This C-banding pattern seems to be characteristic of spiders. Comparative analysis of chromosome complements in Sparassidae indicates that 2n = 42/44 (X₁X₂0/X₁X₁X₂X₂) (male/female) may represent the ancestral karyotype for Polybetes.

A systematic review of some Australasian species previously allocated to the chernetid genus Sundochernes Beier 1932 reveals numerous discrepancies from the type species, S. modiglianii (Ellingsen 1911). Three of these species are removed to the genus Troglochernes Beier 1969, previously known from only a single troglobitic species, and a fourth is removed to a new genus. Troglochernes contains six species: the type species T. imitans Beier 1969 from caves on the Nullarbor Plain, Western Australia; three species newly transferred from Sundochernes, T. guanophilus (Beier 1967) new combination, from Fig Tree Cave, New South Wales, T. dewae (Beier 1967) new combination, from bird nests in New South Wales, Queensland and Western Australia, T. novaeguineae (Beier 1965) new combination, from central Papua New Guinea; and two new species, T. cruciatus Volschenk, new species from Rope Ladder Cave, North East Queensland and T. omorgus Harvey & Volschenk, new species from a beetle in Queensland. The Lord Howe Island endemic pseudoscorpion Sundochernes grayi Beier 1975 is transferred to a new genus, Satrapanus Harvey & Volschenk, as it lacks the diagnostic features of Sundochernes. Problems with the generic allocation of species currently placed within Sundochernes are discussed and the female genitalia of Nesochernes gracilis Beier 1932 and Paraustrochernes victorianus Beier 1966 are illustrated for the first time. Troglochernes imitans is one of the most highly modified troglobitic members of the Chernetidae, displaying extremely elongate pedipalps and legs suggesting an extended period of isolation from ancestral epigean populations. The remaining cave-dwelling species, T. cruciatus and T. guanophilus, are less modified and show fewer morphological modifications which may suggest more recent colonization of the cave environments.

Tarantula spiders of the genus Brachypelma Simon 1891 are the only complete genus of arachnids protected from international trade under CITES law. To better understand the genetic cohesion of spiders within this genus, we evaluated multiple genetic fragments (totalling about 2200 bp) for their ability to recover population sub-structure among wild-caught Brachypelma vagans (Ausserer 1875) from Belize. We used a novel non-lethal method of tissue sampling, by inducing autospasy of the medial leg. This method allowed us to release wild-caught individuals of this protected species after DNA sampling. We used arachnid specific PCR primers to amplify targeted regions of B. vagans DNA, testing various combinations for consistency. We compared mitochondrial fragments from two populations of B. vagans (∼50 km apart) for variation in mitochondrial 16S lrRNA (plus 5′ ND1), CO1, and the nuclear ITS-2 spacer. Both lrRNA-ND1 and CO1 provided congruent estimates of population subdivision, and indicated that lrRNA-ND1 contained the greatest variation. The nuclear ITS-2 was surprisingly short (193 bp) and relatively invariant across B. vagans. While both mitochondrial fragments appear suitable to elucidate population subdivision and historical processes in B. vagans, we suggest that mitochondrial markers may overestimate population division in B. vagans. We conclude that along with valuable inferences from mitochondrial regions, the characterization of population sub-structure in tarantula spiders will be enhanced by other estimates from alternate nuclear fragments.

Pholcidae (Haplogynae) encompasses 967 described species, of which only 14 have been cytogenetic analyzed. Several chromosomal features have already been described including presence of meta- and sub-metacentric chromosomes and sex determination chromosome system (SDCS) of the X, X₁X₂Y, and X₁X₂ types, which contrast with the telo- and acrocentric chromosomes and SDCS of the X₁X₂ type typical of entelegyne spiders. To obtain further cytogenetic information for the family, we examined two pholcid species, Crossopriza lyoni (Blackwall 1867) and Physocyclus globosus (Taczanowski 1874) using both conventional staining and silver staining techniques. Crossopriza lyoni exhibited 2n = 23 = 22 X in males and 2n = 24 = 22 XX in females, while P. globosus showed 2n = 15 = 14 X and 4n = 30 = 28 2X, both in male adults, 2n = 16 = 14 XX in female adults and embryos, and 2n = 15 = 14 X in male embryos. Both species revealed predominately metacentric and submetacentric chromosomes and a SDCS of the X/XX type. The cytogenetic data obtained in this work and those already recorded for C. lyoni indicate interpopulational and intraspecific numerical chromosome variation, suggesting the presence of chromosomal races or cytotypes in this species. The intraindividual numerical chromosome variation observed in male adult specimens of P. globosus may be explained by the presence of cytoplasmatic bridges between germ cells. The use of the silver staining technique to reveal the nucleolar organizer region (NOR) showed that chromosome pairs 4 and 6 and the X chromosome in C. lyoni are telomeric NOR-bearers, and that the chromosome pair 2 in P. globosus possesses a proximal NOR in the long arm.

An unattended trap was designed to sample and retain spiders dispersing from agricultural grassland and crops. Traps comprised a removable bottle-trap fixed to the top of a vertical metal rod or “climbing-stick” that spiders climbed during normal pre-ballooning behavior. Bottle-traps caught over eight times more spiders than sticks treated with insect trapping adhesive. Draping sticks with nets increased the effective area of the traps and increased the catch size threefold. On average, 9.1% of spiders were lost from traps during the daytime sampling period. No difference in average rate of loss of spiders from the bottle-traps was observed between night and daylight hours. The bottle-trap design is economical and simple to construct, erect and operate. Continuous sampling also allows multiple traps to be used simultaneously in various locations.

The monotypic genus Hippasella Mello-Leitão 1944 is revised, and its type-species H. nitida Mello-Leitão 1944 is considered a junior synonym of Tarentula guaquiensis Strand 1908, from Bolivia. Hippasella guaquiensis (Strand) comb. nov. is redescribed and the female genitalia are illustrated for the first time. This species now is recorded from Peru, Bolivia and Argentina. It appears to prefer vegetation near water.

RESUMO.O gênero monotípico Hippasella Mello-Leitão 1944 é revisado e sua espécie-tipo H. nitida Mello-Leitão 1944 é considerada um sinônimo júnior de Tarentula guaquiensis Strand 1908, da Bolívia. Hippasella guaquiensis (Strand) comb. nov. é redescrita e a genitália da fêmea é ilustrada pela primeira vez. Esta espécie é agora conhecida do Peru, Bolívia e da Argentina, onde parece preferir a vegetação próxima à água.

The new species Eukoenenia maroccana is described from six specimens (two males, two females and two immatures) collected in Kef Aziza Cave, Morocco, and is distinguished from all other Eukoenenia species by the presence of thickened opisthosomal glandular setae in males on sternites IV– VI. The genitalia and chaetotaxy of both adult sexes show differences from other species of Eukoenenia and are discussed in this paper.

RESUMEN. Se describe Eukoenenia maroccana a partir de seis ejemplares (dos machos, dos hembras y dos inmaduros) capturados en la gruta de Kef Aziza, Marruecos. Lo más destacable y del todo singular de esta nueva especie es la particular presencia de setas glandulares esternales engrosadas del macho, la genitalia y resto de quetotaxia de ambos sexos.

Cynorta conspersa (Perty 1833), the type species of Cynorta Koch 1839, is redescribed, based on abundant material from the lower Amazon basin, Brazil. A neotype is designated for this species and the species Cynorta mayi Mello-Leitão 1931 is herein considered a junior subjective synonym. Genital morphology of the species is described for the first time. An effort has been made to detect diagnostic characters for the genus Cynorta, which was used in many different senses in the past and includes a large number of unrelated Neotropical species.

RESUMEN. Es redescrita Cynorta conspersa (Perty 1833), especie tipo del género, con base en abundante material proveniente de la cuenca del bajo Amazonas de Brasil. Es designado un neotipo para esta especie y la especie Cynorta mayi Mello-Leitão 1931 es considerada como su sinónimo junior subjetivo. La morfología genital es descrita por primera vez. Ha sido hecho un esfuerzo para detectar caracteres diagnósticos del género Cynorta, el cual fue usado en el pasado con muchos significados diferentes, incluyendo un gran número de especies neotropicales no relacionadas.

This study elucidates the homology of elements of the male palps in the spider family Theridiidae. We survey and illustrate 60 species from 29 out of the 86 currently recognized genera representing all subfamilies. The study is buttressed by a phylogenetic framework, and uses a new method to evaluate critically competing homology hypotheses based on various criteria. Among the classic criteria for homology, topology performed better than special similarity, and much better than function. Guided by those results, we propose names for and correspondences among the broad diversity of theridiid palpal tegular sclerites. We discuss the phylogenetic utility and distribution of key palpal characteristics, and evaluate existing evolutionary hypotheses of the theridiid palp and its components.

Four species from three families of spiders were exposed to sublethal concentrations of the neurotoxic pesticide malathion: Schizocosa ocreata (Hentz 1844), Rabidosa rabida (Walckenaer 1837), Frontinella communis (Hentz 1850), and Salticus scenicus (Clerck 1757). Spider activity was recorded using a proprietary computer vision system equipped with artificial intelligence routines. Exposure to malathion changed the spiders' propensity to move, levels and patterns of activity, and distance moved. Dosed spiders increased their activity between 12 and 40%, depending on the species. Continuous recordings for ≥ 24 h revealed the peak activity for dosed R. rabida and S. scenicus was shifted ∼ 1 h earlier than controls. Spiders exposed to malathion also significantly increased the distance they moved per locomotory bout. This is consistent with the action of an organophosphate neurotoxin acting as an acetylcholinesterase inhibitor. Thus, exposure to sublethal doses of malathion appears to affect the neural basis for these spider's normal diel periodicities, time budgets, and patterns of locomotion, probably reducing their efficiency as agents of biological control.

A junior homonym was detected amongst the Arachnida and the replacement name Sandokan is proposed for Oncopus Thorell 1876 (Opiliones, Laniatores). Accordingly, nine new combinations are herein proposed for all nine valid species currently included in Oncopus (Opiliones). In addition, we propose the replacement name Sandokanidae new name for Oncopodidae.