Epibiotic mites associated with the invasive Chinese mitten crab Eriocheir sinensis – new records of Halacaridae from Poland **This research was supported by grant No. N304 082 31/3219 from the Polish Ministry of Education and Science.

AbstractSeven epibiotic halacarid mites (Caspihalacarus hyrcanus, two species of Copidognathus, Halacarellus petiti, Porohalacarus alpinus, Soldanellonyx monardi and S. chappuisi), two oribatid mites (Hydrozetes lacustris and Trhypochthoniellus longisetus) and one water mite (Piona pusilla) were found on the setae-covered claws of eighteen Chinese mitten crabs (Eriocheir sinensis) collected from fresh and brackish waters in Poland and Germany. The most abundant of the 111 mite individuals recorded was one of the Copidognathus species (N=52); this was followed by H. petiti (N=38) and C. hyrcanus (N=13). This is the first record of H. petiti and of the genus Copidognathus from Polish waters. The possibility of migrating over long distances assisted by catadromous mitten crabs enhances mite dispersal, as well as their introduction to new environments

Zelotes erebeus (Thorell, 1871) (Araneae: Gnaphosidae) in Poland and its distribution in Europe

Zelotes erebeus (Thorell, 1871) is a thermophilic species occurring in southern, western and central Europe. It was excluded from the checklist of Polish spiders because of synonymization issues. This paper corrects the published data and lists new localities in western and central Poland. The sites of Z. erebeus discovered near Swinoujscie, Czarnków and Torun, move northwards the northern range limit of this thermophilous species in Europe. Data on the distribution of this species in eastern Europe and the Caucasus are also corrected - these records relate to the closely related species Z. khostensis Kovblyuk & Ponomarev, 2008. Figures of female and male genitalia of Z. erebeus are presented

Inclusion of juvenile stages improves diversity assessment and adds to our understanding of mite ecology – A case study from mires in Norway

Arachnid orders, Mesostigmata, Trombidiformes, and Sarcoptiformes, commonly known as ‘mites’, are abundant in mires, both as adults and as juveniles. However, due to the challenges of identification, the juvenile forms are often excluded from analyses. This is the first study in mires that included all three mite orders identified to the species level, including juvenile instars. We aimed to compare how diversity and the response to ecological variables differed if only the adults (ad) vs. the total number of specimens (ad+juv) are considered. Samples of 20 Sphagnum species (five subgenera) were collected and mites were extracted using Berlese funnels. Overall, nearly 60,000 mites were analyzed; of these Mesostigmata made up 1.87% of the total, Trombidiformes −0.27%, and Sarcoptiformes −97.86%. The study revealed 154 species (33 Mesostigmata, 24 Trombidiformes, and 97 Sarcoptiformes), the highest diversity of mites ever reported from mires. The inclusion of juveniles increased observed species richness by 6%, with 10 species (one Mesostigmata, six Trombidiformes, and three Sarcoptiformes) represented only by juvenile forms. Seventeen species are new to Norway (four Mesostigmata, one Sarcoptiformes, and 12 Trombidiformes, including five undescribed species of Stigmaeidae and Cunaxidae). Four of these were represented in the samples only by juveniles. Including the juveniles explained a greater amount of the variability of Trombidiformes (explanatory variables account for 23.60% for ad, and 73.74% for ad+juv) and Mesostigmata (29.23% − ad, 52.91% − ad+juv), but had less of an impact for Sarcoptiformes (38.48% − ad, 39.26% − ad+juv). Locality, Sphagnum subgenus and species, wetness, and trophic state significantly affected the mite communities and should be taken into consideration when studying mires. Since juvenile stages contribute significantly to mite diversity in mires, they should also be included in mite studies in other habitats.publishedVersio

The influence of the landscape structure within buffer zones, catchment land use and instream environmental variables on mollusc communities in a medium-sized lowland river

The world’s freshwater molluscan fauna is facing unprecedented threats from habitat loss and degradation. Declines in native populations are mostly attributed to the human impact, which results in reduced water quality. The objectives of our survey were to analyse the structure of the mollusc communities in a medium-sized lowland river and to determine the most important environmental variables at different spatial scales, including landscape structure, catchment land use and instream environmental factors that influence their structure. Our survey showed that a medium-sized river, that flows through areas included in the European Ecological Natura 2000 Network Programme of protected sites, provides diverse instream habitats and niches that support 47 mollusc species including Unio crassus, a bivalve of Community interest, whose conservation requires the designation of a special conservation area under the Habitats Directive Natura 2000. This survey showed that mollusc communities are impacted by several environmental variables that act together at multiple scales. The landscape structure within buffer zones, catchment land use and instream environmental variables were all important and influenced the structure of mollusc communities. Therefore, they should all be taken into consideration in the future restoration of the river, future management projects and programmes for the conservation of biodiversity in running waters. The results of this study may be directly applicable for the rehabilitation of river ecosystems and are recommended to stakeholders in their future decision concerning landscape planning, monitoring species and their habitats, conservation plans and management in accordance with the requirements of sustainable development

Arrenurus claviger Koenike 1885

<i>Arrenurus claviger</i> Koenike, 1885 (219) <p>(Fig. 2, Tables 1, 2)</p> <p> <i>Arrenurus calycularis</i> Georgévitsch, 1906 (143)</p> <p> <b>Material examined:</b> Progeny from a ten females collected from a pool in a ploughed field near Trzebień, Dolice district, Poland, 53o17’N, 15o27’E, among reed­marshes, 1 May 1998.</p> <p> <b>Diagnosis:</b> Dorsal plate egg­shaped with small anterior­lateral indentations, Lp2 and Mh1 bipectinate; median margins of CpI 1.5 times longer than the CpII median margins which are a little longer than CpIII margins; Expp pentagonal­shaped, its width equal to its length, Exp located anterior to the centre of Expp and above the E2 setae; IITi10 long, pectinate, and situated almost in the same place as IITi9, IIITa13 pectinate.</p> <p> <b>Description:</b> The egg­shaped dorsal plate is widest in the middle of its length and narrows in the posterior part. The anterior margin is slightly convex and the posterior one is pointed. The anterior­lateral indentations are fairly small, with slightly obtuse angles, and reach to about one­fifth of the plate length and one­fifth of its width. Seta Lpl is tripartite, setae Lp2 and Mh1 are bipectinate, the remaining setae are smooth (Fig.2).</p> <p>The median margins of CpI are 1.5 times longer than the CpII median margins which are a little longer than CpIII ones, the ratio is 1.5/1.1/1. Setae C1, C2, C3 and V3 are bipectinate, C4, Lh2 and Lh3 are pectinate and the remaining setae are smooth. The distance between the C4 seta and the CpIII median margin is 1.5 times longer than the distance between the C1 seta and CpI median margin (Table 1, Fig. 2).</p> <p>The excretory pore plate is pentagonal­shaped, its width is equal to its length. The excretory pore is located anterior to the centre of the plate and above the E2 setae (Table 1, Fig. 2).</p> <p> The pedipalps are typical for <i>Arrenurus</i> species. Seta PIII1 is bipectinate, PIV1 and PV6 are fairly thin and PV8 is fairly long (Table 1, Fig. 2). The first segment of the chelicerae is bottle­shaped, with one margin flat and the other hook­like (Fig. 2).</p> <p>The proportions of segments are more or less the same on each limb. The shortest segment, the trochanter, constitutes about 2/3 of the femur and genu which are of the same length; the tibia is 1.5 times longer and the tarsus 2 times longer (Table 2). Seta ITi8 is thin and long, IITi10 is long, pectinate, and situated almost in the same place as IITi9. Setae IIIGe2, IIITi7 and IIITi8 are fairly long and bipectinate (Fig. 2).</p>Published as part of <i>Zawal, Andrzej, 2006, Larval morphology of Arrenurus cuspidifer Piersig, A. claviger Koenike, and A. latus Barrois & Moniez (Acari: Hydrachnidia), pp. 55-68 in Zootaxa 1276</i> on pages 62-63, DOI: <a href="http://zenodo.org/record/173333">10.5281/zenodo.173333</a&gt

Morphology of larval stages of Arrenurus cuspidator (O. F. Müller) and A. maculator (O. F. Müller) (Acari: Hydrachnidia)

Zawal, Andrzej (2006): Morphology of larval stages of Arrenurus cuspidator (O. F. Müller) and A. maculator (O. F. Müller) (Acari: Hydrachnidia). Zootaxa 1194: 57-68, DOI: 10.11646/zootaxa.1194.1.

Arrenurus cuspidifer Piersig 1986

<i>Arrenurus cuspidifer</i> Piersig, 1986 (76, 90) <p>(Fig. 1, Tables 1, 2)</p> <p> <b>Material examined:</b> Progeny from a single female collected from a lowland bog, near Lublin, Poland, 51o24’N, 23o24’E, among sedges, 28 May 2004.</p> <p> <b>Diagnosis:</b> Dorsal plate egg­shaped with small anterior­lateral indentations; median margin of CpIII slightly shorter than CpII, CpI twice longer; Expp pentagonal­shaped, its width clearly exceeds its length, Exp located posterior to the centre of the plate and at the same level as the E2 setae; IITi10 long and located near IITi9, IIITi10 short, thick and located near IIITi9, IIITa13 smooth.</p> <p> <b>Description:</b> The egg­shaped dorsal plate is widest in the first third of its length and narrows in the posterior part. Its anterior margin is slightly convex and the posterior margin is rounded. Anterior­lateral indentations are small, with slightly obtuse angles, and reach to about one­quarter of the plate width and one­sixth of its length. Seta Lpl is tripartite, the remaining setae are smooth.</p> <p>The median margins of CpIII are slightly shorter than median margins of CpII, and CpI median margins are twice as long. The ratios of CpI/CpII/CpIII are 2.5/1.2/1. All setae on the coxal plate are smooth. Distance between the C4 seta and CpIII median margin is twice the distance between C1 and CpI median margin. Distance between setae C1 and C2 is fairly small.</p> <p>to be continued.</p> <p> <i>A. latus</i> (n=8) <i>A. latus</i> (Stechmann 1977) range mean standard range deviation</p> <p>* Stechmann (1977) reported the Mh1­Mh1distance; the value given here was obtained by calculating [(Mh1­Mh1) ­ (Mp2­Mp2)]/2</p> <p>** Stechmann (1977) reported the Mp1­Mh1 distance; the value given here was obtained by calculating (Mp1­Mh1) ­ (Mp1­Mp2)</p> <p> <i>latus</i>.</p> <p>The excretory pore plate is pentagonal­shaped, its width clearly exceeds its length. The excretory pore is located posterior to the centre of the plate and is about at the same level as the E2 setae.</p> <p> The pedipalps are typical for <i>Arrenurus</i> species. Seta PIII1 is bipectinate, PIV1 is fairly large, all setae on PV are fairly thin and PV8 is fairly short. The first segment of the chelicerae is bottle­shaped, slightly bent posteriory and fairly short.</p> <p>The proportions of segments are more or less the same on each limb. The shortest segment, the trochanter, constitutes about 2/3 of the femur and genu which are of the same length; the tibia is 1.5 times longer and the tarsus 2 times longer (Table 2). Tarsi of all legs (particularly those of the first leg) are fairly thick. Setae ITa13, ITa14, IITa13, IITa14 and IIITa14 are short and thin. ITi8 is short and thin, IITi10 is long and located almost in the same place as IITi9; IIITi10 is short, thick and located near IIITi9. IIITa13 is smooth.</p>Published as part of <i>Zawal, Andrzej, 2006, Larval morphology of Arrenurus cuspidifer Piersig, A. claviger Koenike, and A. latus Barrois & Moniez (Acari: Hydrachnidia), pp. 55-68 in Zootaxa 1276</i> on pages 57-62, DOI: <a href="http://zenodo.org/record/173333">10.5281/zenodo.173333</a&gt

A new species in the water mite subgenus Majumderatax Vidrine, 1993 from Sri Lanka (Acari: Hydrachnidia)

Pešić, Vladimir, Zawal, Andrzej (2018): A new species in the water mite subgenus Majumderatax Vidrine, 1993 from Sri Lanka (Acari: Hydrachnidia). Zootaxa 4457 (2): 346-350, DOI: https://doi.org/10.11646/zootaxa.4457.2.1

Effect of changes in the fractal structure of a littoral zone in the course of lake succession on the abundance, body size sequence and biomass of beetles

Dystrophic lakes undergo natural disharmonic succession, in the course of which an increasingly complex and diverse, mosaic-like pattern of habitats evolves. In the final seral stage, the most important role is played by a spreading Sphagnum mat, which gradually reduces the lake’s open water surface area. Long-term transformations in the primary structure of lakes cause changes in the structure of lake-dwelling fauna assemblages. Knowledge of the succession mechanisms in lake fauna is essential for proper lake management. The use of fractal concepts helps to explain the character of fauna in relation to other aspects of the changing complexity of habitats. Our 12-year-long study into the succession of water beetles has covered habitats of 40 selected lakes which are diverse in terms of the fractal dimension. The taxonomic diversity and density of lake beetles increase parallel to an increase in the fractal dimension. An in-depth analysis of the fractal structure proved to be helpful in explaining the directional changes in fauna induced by the natural succession of lakes. Negative correlations appear between the body size and abundance. An increase in the density of beetles within the higher dimension fractals is counterbalanced by a change in the size of individual organisms. As a result, the biomass is constant, regardless of the fractal dimension

Figure 4 from: Aykut M, Zawal A, Esen Y, Erman O (2018) First record of larvae of the water mite Hydrachna processifera Piersig, 1895 from Turkey (Acari, Hydrachnidia, Hydrachnidae). ZooKeys 738: 89-96. https://doi.org/10.3897/zookeys.738.21021

Larvae of water mite Hydrachna processifera Piersig, 1895 (Acari, Hydrachnidiae) were reported on diving beetles Dytiscus marginalis Linnaeus, 1758 (Coleoptera, Dytiscidae) from Turkey. The redescription of the larva was made. Earlier, the larva H. processifera was described as H. inermis, but it was subsequently synonymized with H. processifera. The larva of H. processifera is a new record for the Turkish fauna. All larvae of H. processifera were found on the mesosternum of the one specimens (prevalence = 16.7%)