František Šťáhlavský

A review of the pseudoscorpion genus Oreolpium (Pseudoscorpiones: Garypinidae), with remarks on the composition of the Garypinidae and on pseudoscorpions with bipolar distributions

Abstract A review of the pseudoscorpion genus Oreolpium Benedict & Malcolm reveals two species, the type species O. nymphum Benedict & Malcolm 1978 from northwestern USA and O. semotum, new species, from southern Tasmania. Oreolpium is most similar to Neominniza Beier, Thaumatolpium Beier and Teratolpium Beier from South America, and to Protogarypinus Beier from southern Australia. These genera are confirmed as members of Garypinidae, and both species of Oreolpium are found to lack glandular setae on sternites VI–VIII, which is an unusual feature for Garypinidae. Oreolpium demonstrates a remarkable bipolar distribution, similar to that of the pseudoscorpion groups Pseudotyrannochthoniidae, Pseudogarypidae and Syarininae, and to several water mite taxa.

Two New Species of Euscorpiops Vachon, 1980 from Thailand and Myanmar (Scorpiones: Euscorpiidae: Scorpiopinae)

Abstract Euscorpiops artemisae sp. nov. from Myanmar and Euscorpiops orioni sp. nov. from Thailand are described and compared with other species of the genus Euscorpiops Vachon, 1980. A key to the species of Euscorpiops is provided. Sexual dimorphism is present, as males of some species have a narrower pedipalp chela than females, while in other species the shape of the chela is the same in both sexes. Males of both new species have the pedipalp chela very narrow, in the male holotype of E. artemisae sp. nov. the chela length to width ratio is 4.13 and in the male holotype of E. orioni sp. nov. it is 4.58. In addition to morphological analysis, we describe also the karyotype of male holotype and paratype of E. orioni sp. nov. Both analyzed specimens have achiasmatic meiosis and the same number of chromosomes (2n=103) with predominance of acrocentric chromosomes gradually decreasing in size. During the first meiotic division we observed one trivalent in both males. This type of multivalent indicates centric fusion or fissions that may cause the differentiation of the karyotypes within the genus Euscorpiops.

The first cytogenetic characterization of atemnids: pseudoscorpions with the highest chromosome numbers (Arachnida: Pseudoscorpiones).

The karyotypes of pseudoscorpions of the family Atemnidae (Arachnida: Pseudoscorpiones) were studied for the first time. Karyotype data for 7 species have been obtained. The diploid chromosome numbers of most species considerably exceed the numbers reported in pseudoscorpions so far, with males ranging between 65 and 143. In spite of this, the sex chromosome system of atemnids is characterized by the same features that are found in the majority of other pseudoscorpions with an X0 system; the X chromosome is metacentric and is the largest chromosome or one of the largest chromosomes of the karyotype. Male meiotic cells of Atemnus politus contain 1 or 2 autosome multivalents; most specimens had 2 multivalents. The multivalents were composed of 4, 6, 8 or 10 chromosomes. Multivalent number and structure was consistent within each of the studied individuals. The same number of chromosomes in all of the males examined suggests that multivalents are generated by reciprocal translocations. The high diversity of multivalents suggests considerable range of translocation heterozygosity in the studied population.

Karyotype Evolution in Harvestmen of the Suborder Cyphophthalmi (Opiliones)

The morphologically uniform suborder Cyphophthalmi represents a basal group of harvestmen (Opiliones). As such, it plays an important role in the reconstruction of the karyotype evolution within this arachnid order. The cytogenetic analysis of 6 representatives of the suborder Cyphophthalmi, namely Miopsalis sp. (2n = 30; Stylocellidae), Austropurcellia arcticosa (Cantrell, 1980) (2n = 30; Pettalidae), Parapurcellia amatola de Bivort & Giribet, 2010 (2n = 32; Pettalidae), Paramiopsalis aff. ramulosus Juberthie, 1962 (2n = 28; Sironidae), Cyphophthalmus duricorius Joseph, 1868 (2n = 24; Sironidae), and Siro carpaticus Rafalski, 1956 (2n = 52; Sironidae) was performed. Fluorescence in situ hybridization with 18S rDNA probe was used to analyze the distribution of major ribosomal RNA genes in harvestmen. We confront the obtained cytogenetic data with current hypotheses on cyphophthalmid phylogeny to reconstruct their karyotype evolution. We conclude that the ancestral karyotype of harvestmen consisted of 2n = 30 elements with 1 chromosome pair bearing terminal rDNA clusters. The rDNA locus was multiplicated in the evolution of Cyphophthalmi. However, decreases as well as increases in the number of chromosomes have been detected in the karyotype evolution of Cyphophthalmi. Our data thus reveal unexpected diversity in cyphophthalmid karyotypes.

Karyotype diversity of pseudoscorpions of the genus Chthonius (Pseudoscorpiones, Chthoniidae) in the Alps

Abstract Pseudoscorpions are found in almost all terrestrial habitats. However, their uniform appearance presents a challenge for morphology-based taxonomy, which may underestimate the diversity of this order. We performed cytogenetic analyses on 11 pseudoscorpion species of the genus Chthonius C. L. Koch, 1843 from the Alps, including three subgenera: Chthonius (Chthonius) C. L. Koch, 1843, Chthonius (Ephippiochthonius) Beier, 1930 and Chthonius (Globochthonius) Beier, 1931 inhabiting this region. The results show that the male diploid number of chromosomes ranges from 21–35. The sex chromosome system X0 has been detected in all male specimens. The X sex chromosome is always metacentric and represents the largest chromosome in the nucleus. Achiasmatic meiosis, already known from the family Chthoniidae, was further confirmed in males of Chthonius. C-banding corroborated the localization of constitutive heterochromatin in the centromere region, which corresponds to heteropycnotic knobs on the standard chromosome preparations. Morphological types and size differentiation of chromosomes in the karyotype suggest that the main chromosomal rearrangements in the evolution of Chthonius are centric or tandem fusions resulting in a decrease in the number of chromosomes. Pericentric inversions, inducing the change of acrocentric chromosomes into biarmed chromosomes, could also be expected. Variability in chromosome morphology and number was detected in several species: Chthonius (Chthonius) ischnocheles (Hermann, 1804), Chthonius (Chthonius) raridentatus, Chthonius (Chthonius) rhodochelatus Hadži, 1930, and Chthonius (Chthonius) tenuis L. Koch, 1873. We discuss the intraspecific variability within these species and the potential existence of cryptic species.

Molecular technique reveals high variability of 18S rDNA distribution in harvestmen (Opiliones, Phalangiidae) from South Africa

Abstract The knowledge of cytogenetics in the harvestmen family Phalangiidae has been based on taxa from the Northern Hemisphere. We performed cytogenetic analysis on Guruia africana (Karsch, 1878) (2n=24) and four species of the genus Rhampsinitus Simon, 1879 (2n=24, 26, 34) from South Africa. Fluorescence in situ hybridization with an 18S rDNA probe was used to analyze the number and the distribution of this cluster in the family Phalangiidae for the first time. The results support the cytogenetic characteristics typical for the majority of harvestmen taxa, i.e. the predominance of small biarmed chromosomes and the absence of morphologically well-differentiated sex chromosomes as an ancestral state. We identified the number of 18S rDNA sites ranging from two in R. qachasneki Kauri, 1962 to seven in one population of R. leighi Pocock, 1903. Moreover, we found differences in the number and localization of 18S rDNA sites in R. leighi between populations from two localities and between sexes of R. capensis (Loman, 1898). The heterozygous states of the 18S rDNA sites in these species may indicate the presence of XX/XY and ZZ/ZW sex chromosomes, and the possible existence of these systems in harvestmen is discussed. The variability of the 18S rDNA sites indicates intensive chromosomal changes during the differentiation of the karyotypes, which is in contrast to the usual uniformity in chromosomal morphology known from harvestmen so far.

Stridulation can suppress cannibalism in a specialised araneophagous predator

Acoustic signalling is widespread in arthropods and appears to be common in spiders, but the function is still unknown in many species. Acoustic signals have several functions and can be used both in interspecific (e.g., to threaten potential predators) and intraspecific (during courtship) communication. In our study, we investigated the intraspecific role of stridulation in the araneophagous Palpimanus spider (Araneae: Palpimanidae). These spiders are specialised in hunting other spiders at all ontogenetic stages. We hypothesised that stridulation is used to avoid cannibalism. We investigated the morphology of the stridulatory apparatus, analysed the acoustic signals that various stages produce, and found two types of stridulation, low- and high-intensity stridulation. Then, we investigated the presence of cannibalism between individuals of variable body size and the use of stridulation during interactions. We found that cannibalism occurred only when the prosoma size difference between the two opponents was more than 200%. Then, we paired conspecific large control Palpimanus with smaller control individual or with individual whose stridulatory organs were impaired and found that impaired spiders suffered significantly higher cannibalism than the control spiders. Our study reveals a novel role of acoustic communication in the conspecific recognition of araneophagous spiders.Significance statementCannibalism is widespread among predatory animals. However, cannibalism might not be an optimal strategy for several reasons and should be a less preferred option for predators. Palpimanus spiders are prey specialised predators preying primarily on other spiders thus the risk of cannibalism is even higher than in generalist predators. These spiders possess stridulatory apparatus and they often stridulate following a contact with conspecifics. We found that cannibalism occasionally occurred during contact with conspecifics and that the probability of cannibalism increased with the size difference between the interacting individuals. When the spiders were not able to stridulate during contact, the probability of cannibalism increased significantly. Our results thus show that Palpimanus spiders use stridulation to reduce cannibalism among unequally sized individuals.

21st International Chromosome Conference (ICC). July 10-13, Foz do Iguaçu, Brazil

amazing diversity of life, including over 2,000 species of vascular plants, exotic mammals such as tapirs, giant anteaters, howler monkeys, ocelots, and jaguars, in addition to hundreds of different bird species and thousands of different insects, the choice of Foz is an excellent analogy for the diverse approaches and systems chromosome biologists explore, and that will be emphasized throughout this conference. The 2016 ICC program offers seven sessions, beginning with a session on Chromosome Structure and Nuclear Architecture, highlighting the influences and interactions chromosomes have on the three-dimensional space of the nucleus. Session II will focus on Specialized Chromosomes, such as sex chromosomes and B chromosomes, whose structure and behavior are often distinguished from that of autosomal chromosomes. Population and Evolutionary Chromosome Biology, the third session, covers a synthesis of chromosome biology and The International Chromosome Conferences (ICC) originated from the Oxford Chromosome Conferences, inaugurated by C.D. Darlington and K.R. Lewis in 1964 and held subsequently in England in 1967 and 1970. The Chromosome Conference grew to an international event with its fourth meeting, held in Jerusalem, Israel in 1972, heralding the beginning of 40 years of technological advances that have expanded our understanding of chromosome biology in model and non-traditional biological systems. Having been hosted in Europe and the United States 16 times since then, this year the ICC will be held across the equator in Foz do Iguaçu, Brazil, on July 10–13, 2016. The event will bring scientists from across the globe to a biannual meeting focused on modern advances in chromosome biology, technology and theory. The Iguaçu National Park, a UNESCO World Heritage Centre, includes the Iguaçu Falls and has been chosen as one of the ‘New Natural Seven Wonders of the World’. Home to an Published online: June 2, 2016I.O. Furo a , R. Kretschmer b , R.J. Gunski c , A.D.V. Garnero c , M.A. Ferguson-Smith d , P.C.M. O ́Brien d , E.H.C. de Oliveira e, f a Programa de Pós-Graduação em Genética e Biologia Molecular, PPGBM, Universidade Federal do Pará, Belém, b PPGBM, Universidade Federal do Rio Grande do Sul, Porto Alegre, and c Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal do Pampa, São Gabriel, Brazil; d Department of Veterinary Medicine, University of Cambridge, Cambridge, UK; e Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belém, and f Laboratório de Cultura de Tecidos e Citogenética, SAMAM, Instituto Evandro Chagas, Ananindeua, Brazil