A new species of the genus Spiritiops Lugo-Ortiz & McCafferty (Ephemeroptera, Baetidae) from the Pantepui biogeographical province

The genus Spiritiops was described by Lugo-Ortiz & McCafferty in 1998. Since then, only the type species, S. silvudus, was reported from different countries, such as Brazil, French Guiana, Surinam and Venezuela. In the last years, various international speleological expedition explored summits of some table mountains called tepuis in Guyana region in south-eastern Venezuela. Here we describe a new species of the genus Spiritiops, found at three tepuis (Auyán-tepui, Churí-tepui and Mt. Roraima) during above mentioned speleological expeditions.Fil: Nieto Peñalver, María Carolina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Derka, Tomáš. Comenius University; Eslovaqui

Checklist, distribution, diversity, and rarity of mayflies (Ephemeroptera) in Slovakia

Despite the essential role of mayflies (Ephemeroptera) in freshwater ecosystems and their long-term use in research and routine biomonitoring in the Carpathian and Pannonian ecoregions, their distribution data are fragmentary and outdated. All published and unpublished data on mayflies from Slovakia was gathered and a database of > 15,000 species records from 2206 localities built with the aims (i) to critically revise available data and assess the completeness of the species inventory, (ii) to identify hotspots of species diversity, and (iii) to provide a benchmark for assessment of species rarity and conservation status in the region. After the critical revision of the data covering more than 100 years, the occurrence of 109 mayfly species in Slovakia was confirmed. The species inventory appears to be nearly complete, as evidenced by the rarefaction curve and a nonparametric species richness estimator. The highest mayfly gamma diversity was recorded below 500 m a.s.l. and in streams of the fifth order, which can be considered hotspots of mayfly diversity in the region. Six species were last recorded before 1990 and thus can be considered extinct in Slovakia. Twenty-nine species could be classified as very rare, with their occurrence frequency decreasing with increasing altitude and most of them being restricted to large lowland rivers and stagnant water habitats in their floodplains. In conclusion, our study provides comprehensive data on key freshwater bioindicators and suggests increasing conservation priorities, especially in lowland river floodplains occupied by several very rare mayfly species

Anticipating where are unknown aquatic insects in Europe to improve biodiversity conservation

Aim: Understanding biodiversity patterns is crucial for prioritizing future conservation efforts and reducing the current rates of biodiversity loss. However, a large proportion of species remain undescribed (i.e. unknown biodiversity), hindering our ability to conduct this task. This phenomenon, known as the ‘Linnean shortfall’, is especially relevant in highly diverse, yet endangered, taxonomic groups, such as insects. Here we explore the distributions of recently described freshwater insect species in Europe to (1) infer the potential location of unknown biodiversity hotspots and (2) determine the variables that can anticipate the distribution of unknown biodiversity. Location: The European continent, including western Russia, Cyprus and Turkey. Methods: Georeferenced information of all sites where new aquatic insect species were described across Europe from 2000 to 2020 was compiled. In order to understand the observed spatial patterns in richness of recently described species, spatial units were defined (level 6 of HydroBASINS) and associated with a combination of a set of socioeconomic, environmental and sampling effort descriptors. A zero-inflated Poisson regression approach was used to model the richness of newly described species within each spatial unit. Results: Nine hundred and sixty-six recently described species were found: 398 Diptera, 362 Trichoptera, 105 Coleoptera, 66 Plecoptera, 28 Ephemeroptera, 3 Neuroptera, 2 Lepidoptera and 2 Odonata. The Mediterranean Basin was the region with the highest number of recently described species (74%). The richness of recently described species per spatial unit across Europe was highest at mid-elevation areas (between 400 and 1000 m), latitudes between 40 and 50° and in areas with yearly average precipitation levels of 500–1000 mm, a medium intensity of sampling effort and low population density. The percentage of protected areas in each study unit was not significantly related to the richness of recently described species. In fact, 70% of the species were found outside protected areas. Main conclusions: The results highlight the urgent need to concentrate conservation efforts in freshwater ecosystems located at mid-altitude areas and out of protected areas across the Mediterranean Basin. The highest number of newly described species in those areas indicates that further monitoring efforts are required to ensure the aquatic biodiversity is adequately known and managed within a context of growing human impacts in freshwater ecosystems.Generalitat de Catalunya 2017SGR1643Ministerio de Ciencia e Innovación TED2021-130328B-I00, RYC2019-027446-

Anticipating where are unknown aquatic insects in Europe to improve biodiversity conservation

Understanding biodiversity patterns is crucial for prioritizing future conservation efforts and reducing the current rates of biodiversity loss. However, a large proportion of species remain undescribed (i.e. unknown biodiversity), hindering our ability to conduct this task. This phenomenon, known as the ‘Linnean shortfall’, is especially relevant in highly diverse, yet endangered, taxonomic groups, such as insects. Here we explore the distributions of recently described freshwater insect species in Europe to (1) infer the potential location of unknown biodiversity hotspots and (2) determine the variables that can anticipate the distribution of unknown biodiversity.This research was carried out in the FEHM-Lab (Freshwater Ecology, Hydrology and Management) research group funded by the ‘Agència de Gestió d'Ajuts Universitaris i de Recerca’ (AGAUR) at the ‘Generalitat de Catalunya’ (2017SGR1643), and it has also been partially supported by the ‘Digit_Artro’ project (‘Hacia la conservación de artópodes ibéricos usando herramientas digi-tales’) funded by the Spanish Ministry of Science and Innovation (TED2021-130328B-I00). DSF is funded by a postdoctoral con-tract from the Spanish Ministry of Science and Innovation (Ramón y Cajal program; RYC2019-027446-I). PP and VP were supported by the P505-20- 17305S grant.S

A time-calibrated ‘Tree of Life’ of aquatic insects for knitting historical patterns of evolution and measuring extant phylogenetic biodiversity across the world

The extent to which the sequence and timing of important events on Earth have influenced biological evolution through geological time is a matter of ongoing debate. In this context, the phylogenetic history of aquatic insects remains largely elusive, and our understanding of their chronology is fragmentary and incomplete at best. Here, after gathering a comprehensive data matrix of 3125 targeted rRNA and protein-coding gene sequences from nine independent gene portions, we built a well-supported time-calibrated phylogenetic tree comprising almost 1200 genera that represent a large proportion of extant families of dragonflies and damselflies (Odonata), mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera). We reviewed the main evolutionary and historical scenarios for each aquatic insect lineage as revealed by our best-scoring molecular tree topology, major ancient radiations, calibrated divergence estimates, and important events in geological history related to the spatial arrangement of land masses, continental drift, and mass extinctions. Molecular dating using the birth-death model of speciation, with a lognormal-relaxed model of sequence evolution informed by transcriptomic constraints, suggested that (i) dragonflies and damselflies first radiated approximately 220 million years (Ma) ago and most extant lineages thrived independently after the Triassic–Jurassic (Tr–J) extinction event; (ii) mayflies underwent bursts of diversification during the Cretaceous; (iii) ancestral divergence separating the stonefly suborders Arctoperlaria and Antarctoperlaria was consistent with geographical isolation after vicariant fragmentation and tectonic splitting of the supercontinent Pangaea around 170 Ma ago; and (iv) the most recent common ancestors of caddisflies extended back to the time of Pangaea, supporting the earliest offshoot of the ‘retreat-making’ Annulipalpia and a sister relationship between the predatory free-living Rhyacophilidae and Hydrobiosidae. Our ‘Tree of Life’ of aquatic insects also resolved shallow phylogenetic relationships related to key evolutionary innovations, such as the convergent evolution of exophytic oviposition in dragonflies or the Jurassic origins of the burrowing lifestyle in mayflies. In this study, we also illustrate how our time-calibrated phylogeny can help to integrate phylogenetic aspects in biogeographical and ecological research across the world. To do so, we used three empirical datasets of stream insects from subarctic Finland, northeastern Spain, and southeastern Tibet as exemplary cases. These examples of application tested ecogeographical mechanisms related to (i) the responses of size structural resemblances to phylogenetic constraints, and patterns of (ii) phylogenetic relatedness and (iii) phylogenetic uniqueness along elevational and flow-intermittence gradients, respectively. We emphasise how specific details capturing different aspects of phylogenetic variation are dependent on the geological, geographical, and environmental contexts in different drainage basins. We finally highlight potential venues for future research, including evaluations of geographical patterns of phylogenetic diversity in space and time, evolution of ecological characters in relation to palaeoclimatic variation, and development of complementary algorithms for conservation prioritisation of evolutionarily valuable bioregions for aquatic insects. Overall, we hope that this work will stimulate multidisciplinary research efforts among different areas of the biogeosciences towards safeguarding the phylogenetic heritage of extant aquatic insects across the world.We are thankful to Luis Mauricio Bini (Universidade Federal de Goiás, Brazil), with whom we discussed aspects of this study and whose insightful comments helped significantly improve earlier versions of the manuscript. This work was supported by the Academy of Finland [grant number 331957]; the European Union Next Generation EU/PRTR [grant number AG325]; the ICREA Academia 2021 award from the Catalan Institution for Research and Advanced Studies; the National Natural Science Foundation of China [grant numbers U22A20454 and 32271664]; the Scientific Grant Agency of the Ministry of Education, Science, Research, and Sport of the Slovak Republic and the Slovak Academy of Sciences VEGA [grant number 2/0084/21]; the Government of Spain Ministry of Economy and Competitiveness [grant number CTM2017-89295-P, cofounded by the European Regional Development Fund]; and the Government of Spain Ministry of Science and Innovation [grant numbers RYC2020-029829-I and PID2022-140081OB-100]. We thank all people involved with the field surveys of the three exemplary case studies included here. We would also like to thank the Supercomputing Centre of Castilla y León (SCAYLE) for letting us use their resources and infrastructure for CPU-intensive tasks. Illustrations and pictures used throughout this paper are from the Atlas of Common Freshwater Macroinvertebrates of Eastern North America (funded by the National Science Foundation; https://www.macroinvertebrates.org/; under CC BY-NC 4.0).Peer reviewe

Setting Out and Measurement of Track Geometric Parameters for the Purposes of Reconstruction in Krnov City

Import 22/07/2015V předložené práci je zpracováno vytyčení a zaměření prostorové polohy koleje pro účely rekonstrukce kolejí a výhybek na vlečce v Krnově. První část se věnuje prověření polohy a výšky bodů navržené vytyčovací sítě. Následně je proveden rozbor přesnosti měření a popsán postup vytyčení podrobných bodů. V další části je zpracováno kontrolní měření nově zřízených konstrukcí. Závěr práce se zabývá geodetickou částí dokumentace skutečného provedení stavby.This thesis treats of setting out and measurment of position of track for the reconstruction of tracks and switches on a siding in Krnov. The first part describes a verification of position and height of designed set of points. Following is an analysis of the precision of measurment and is described process setting out of position points. The next section is elaborated control measurements newly established rail structures. Finally of the thesis there is processed the surveying parts of the documentation of actual construction.544 - Institut geodézie a důlního měřictvívýborn

Measurement of Track Geometric Parameters in 21.875 to 22.325 km Suchdol n.O. - Budišov n.B. Track

Import 26/06/2013V předložené práci je zpracováno zajištění prostorové polohy koleje v km 21,875 až 22,325 železniční trati Suchdol nad Odrou – Budišov nad Budišovkou. První část se věnuje popisu bodového pole včetně nezbytného doplnění jeho bodů. Následně je popsán postup měření polohopisu a výškopisu zajišťovacích značek. V další části je proveden výpočet souřadnic a výšek zajišťovacích značek. Na závěr je zpracována dokumentace zajištění prostorové polohy koleje podle předepsaných pravidel.This thesis treats of the track geometry marking in 21.875 to 22.325 km Suchdol nad Odrou – Budišov nad Budišovkou track. The first part describes set of points including the necessary complement its points. Following describes the procedure of measurement planimetric and altimetry permanent markers. The next section is performed a calculate the coordinates and heights of permanent markers. Finally of the thesis there is processed the documentation of track geometry marking according to prescribed rules.Prezenční544 - Institut geodézie a důlního měřictvívýborn

A new species of the genus Spiritiops Lugo-Ortiz & McCafferty (Ephemeroptera, Baetidae) from the Pantepui biogeographical province

The genus Spiritiops was described by Lugo-Ortiz & McCafferty in 1998. Since then, only the type species, S. silvudus, was reported from different countries, such as Brazil, French Guiana, Surinam and Venezuela. In the last years, various international speleological expedition explored summits of some table mountains called tepuis in Guyana region in south-eastern Venezuela. Here we describe a new species of the genus Spiritiops, found at three tepuis (Auyán-tepui, Churí-tepui and Mt. Roraima) during above mentioned speleological expeditions.Fil: Nieto Peñalver, María Carolina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Biodiversidad Neotropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Derka, Tomáš. Comenius University; Eslovaqui

Leptohyphes kukenan Molineri & Derka 2020, sp. nov.

<i>Leptohyphes kukenan</i> sp. nov. <p>(Figs. 1–20)</p> <p> <b>Type material:</b> Holotype female mature nymph (MLBV) from VENEZUELA, Est. Bolívar, Kukenán river below Kukenán Tepui, N 05.15601º, W 60.82507º, 1631 m a.s.l., 25/xi/2015, T. Derka col. Paratypes: 6 female and 1 male nymphs, same data as holotype (1 female in MLBV, rest in IBN); 1 female nymph (IBN, slide IBN833 CM) from VENEZUELA, Est. Bolívar, small creek in Kukenán Tepui base camp, N 05.16636º, W 60.82384º, 1875 m a.s.l., 25/xi/2015, T. Derka col.</p> <p> <b>Diagnosis:</b> 1) male compound eyes enlarged and divided (Figs. 3–4); 2) tubercles on body absent (Figs. 1, 3); 3) forefemur length/maximum width 2.1 (Fig. 10); 4) fore and hind margin of middle and hind femora with spines on strong elevated sockets (Fig. 12); 5) small pale spots (”pale pits”) cover the surface of head, thorax and femora (dorsally) and submentum (ventrally); 6) dorsum of hind femora with a mediolongitudinal ridge and a row of 16–20 minute spines (Fig. 12); 7) tarsal claws with 4–5 marginal denticles and 2 subapical denticles (Fig. 11); 8) pronotum with large rounded lateral projection (Figs. 1–2); 9) hind wing pads absent in female; 10) gill formula 8/7/7/4/1, gill V without ventral extension on dorsal lamella (Figs. 13–20).</p> <p> <b>Mature nymph:</b> Length of female (mm) (n=3): body, 8.9–9.1; caudal filaments, 7.0–8.0. Length of male (mm) (n=1): body, 8.5; caudal filaments (broken at base). General coloration whitish to yellowish light brown, with small pale spots on head, thorax and legs (Figs. 1, 3). Head: shaded with black widely except anteriorly to each ocellus, on occiput forming a net-like pattern (Fig. 2, 4); and with small pale spots. Antennae yellowish white. Compound eyes of female rounded and small as usual, male eyes enlarged and divided in two portions (Figs. 3–4), line between both parts hardly visible. Mouthparts (Figs. 5–9): labrum with single long setae dorsally, some of them forming a transverse submedian row (Fig. 5); anteromedian emargination shallow, with a row of bifid micro-setae along ventral edge of fore margin (Fig. 5, detail); hypopharynx with rounded small superlinguae and lingua; maxilla with well-developed 3-segmented palpus (Fig. 8); mandibles relatively stout (Figs. 6–7); labium with large and elongated submentum, completely covered with pale spots ventrally (Fig. 9). Thorax. Nota brownish shaded with black widely except median area paler, wingbuds grayish on costal margin; sterna paler. Pronotum with rounded lateral projection (Figs. 1, 3). Mesonotum with subtriangular blunt anterolateral projection (Figs. 1, 3). Hind wingpad absent in female. Legs yellowish slightly shaded gray dorsally except mediolongitudinal pale line on middle of femora, dorsum of all femora completely covered by small pale spots. Ratio length fore femur/hind femur = 0.55. Foreleg (Fig. 10): ratio femur length/maximum width 2.1; transversal row at 0.6 from base to apex; fore margin with small spines, hind margin with fringed rounded spines (Fig. 10, detail) distally to transversal row, all spines mounted on elevated sockets. Foretibia slightly longer than femur, with tiny spines along inner margin and a longitudinal ridge along outer margin. Tarsus 1/2 the length of tibia with row of setae in inner margin; tarsal claw with five marginal denticles, and 2 subapical submarginal denticles (Fig. 11). Middle and hind legs (Fig. 12) similar in form and setation to each other (middle leg smaller). Ratio hind femur length/maximum width 2.0; fore margin with row of tiny rounded spines mounted on large sockets (on basal half this row is double), hind margin with 38–40 rounded small spines on very elevated sockets (see detail in Fig. 12), dorsal surface with longitudinal ridge covered by 18–20 small spines. Tibia slightly longer than femur, with dorsal ridge, inner and outer margins with spines, those on hind margin stronger and mounted on elevated sockets. Tarsus 0.25 the length of tibia, inner margin with setae, tarsal claw as in foreleg. Abdomen (Figs. 2, 3, 13) yellowish diffusely shaded with gray on terga as in Figure 2; terga glabrous, except rounded small paired spines submedially on terga VI–IX (Fig. 13); segments III–VI forming lateral flanges; small posterolateral projections present on VII–IX. Gills (Figs. 14–20): operculate gill light brownish-gray with whitish margins, ventrally with membranous and relatively short ”basal spine” and two fringed lamellae (Figs. 14–16); other gills grayish to hyaline, gills III–IV also with fringed lamellae (Figs. 17–18). Gill formula 8/7/7/4/1. Caudal filaments with whorl of short setae at joinings, with darker annuli at base on females (broken off and lost in male).</p> <p> <b>Adults:</b> unknown.</p> <p> <b>Etymology</b>: The species is named after Kukenán tepui, a table mountain in southeastern Venezuela, on which talus it was found.</p> <p> <b>Distribution.</b> Only known from Kukenán tepui (Figs. 21–22), Pantepui region, Venezuela.</p> <p> <b>Discussion:</b> <i>Leptohyphes kukenan</i> <b>sp. nov.</b> can be distinguished from all its congeners by the list of characters given in the diagnosis. It is similar to <i>L. populus</i> Allen (1973) because of the uncommon division of male eyes in a dorsal and a ventral portion. Other characters common to both species may also appear in other species of the genus, for example the large elevated sockets on femoral spines. The new species can be separated from <i>L. populus</i> because the spines on femora and tibia of the new species are relatively smaller and fewer; the form of the submentum (longer in the new species), and the paired subapical denticles on tarsal claws (absent in <i>L. populus</i>). Gills are not described for <i>L. populus</i>, but in the new species, although preserving the general shape and aspect of the genus, they are different in their structure from other <i>Leptohyphes</i>: smaller ventral lobes arise consecutively from larger ones, so they are imbricated. This pattern (as well as the divided eyes) is plesiomorphic in Leptohyphidae, being present only in <i>Amanahyphes</i> Salles & Molineri (2006), and also in related families Melanemerellidae and Coryphoridae (Molineri 2006). Another character that can be interpreted as plesiomorphic in the new species is the presence of paired subapical denticles on the tarsal claws, which is widespread in the family but in <i>Leptohyphes</i> it is almost always single and asymmetrical (Molineri 2003, 2006). Small pale spots have been described in other species of <i>Leptohyphes</i>: <i>L. liniti</i> Wang <i>et al</i>. (1998), <i>L. petersi</i> Allen (1967), <i>L. murdochi</i> Allen (1967), <i>L. alleni</i> Brusca (1971), and <i>L. andina</i> Molineri <i>et al</i>. (2016), but their function is unknown (Baumgardner & McCafferty 2010). We have observed in other species of the genus some intraspecific variation on the number and extent of such pale pits.</p> <p> <b>Ecological notes:</b> Both sites were located on mountain watercourses with relatively cool water (Figs. 21–22). The type locality is situated on a cascading, 5–6 m wide river with bottom formed by boulders and stones, the water temperature oscillated around 17 ºC. The surrounding area was a secondary savanna, trees were preserved on the banks. The stream originates on the plateau of Kukenán tepui at an altitude about 2,600 m a.s.l. The second site was a stream 0.4 m wide, with gravel bottom with many tree roots and debris. The water temperature 15.4 ºC indicates that the sampling site was situated near the spring. The surrounding area was a dense young forest regenerating after a fire.</p>Published as part of <i>Molineri, Carlos & Derka, Tomáš, 2020, A rare new species of Leptohyphes Eaton (Ephemeroptera: Leptohyphidae) from the Lost World, pp. 261-268 in Zootaxa 4786 (2)</i> on pages 262-267, DOI: 10.11646/zootaxa.4786.2.7, <a href="http://zenodo.org/record/3874770">http://zenodo.org/record/3874770</a&gt

Parakari churiensis Nieto & Derka, 2011, new species

Parakari churiensis new species Nieto & Derka (Figs. 2 –3, 15– 30) Male imago (Figs. 15–16). Length: body: 6.4–6.5 mm; fore wings: 6.9 –7.0 mm. Head yellowish brown, antennae yellowish brown. Eyes (Fig. 16): dorsal portion of turbinate eyes orange brown, stalk brownish, ventral portion black, bases of ocelli black. Thorax brownish (Fig. 15), mesoscutum (MS) pale brown, submesoscutum (SMS) brownish. Metascutellum brownish, medial projection pale brown. Pleurae yellowish brown. Prosternum pale yellow, meso and metasterna yellowish brown. Legs pale yellow. Wings hyaline (Fig. 17), costal and subcostal spaces of fore wings translucent. Abdomen pale yellow except segments VII–VIII brownish. Genitalia (Fig. 18) yellowish. Cerci broken-off and lost. Female Imago. Length: body: 5.7 –6.0 mm; fore wings: 6.7–6.8 mm. Head reddish brown, antennae reddish brown; compound eyes blackish. Thorax: pronotum reddish brown, mesoscutum yellowish, submesoscutum brownish, metascutellum yellowish brown. Pleurae and sterna yellowish. Legs yellowish. Wings hyaline, costal and subcostal space of fore wings translucent. Abdomen: segments I–VIII reddish brown, segments IX–X pale yellow, sterna pale yellow. Cerci broken off and lost. Nymph (Figs. 2–3). Length: body: 5.2–5.5 mm; cerci: 2.5–2.6 mm; terminal filament: 2.3–2.4 mm. Head yellowish brown. Eyes: compound eyes orange brown, ocelli black. Antennae yellowish brown. Mouthparts (Figs. 19–24): Labrum (Fig. 19 a) subquadrangulate, dorsally with two subapical setae near midline, one short and one long. Left mandible (Fig. 20) with incisor positioned at obtuse angle to mola area, thumb of mola area transverse to anterior margin. Right mandible (Figs. 21 a–b) with incisors elongated, prostheca bifid basally. Hypopharynx (Fig. 22) with lingua subequal in length to superlinguae. Maxillae (Fig. 23 a) with crown with two long pectinated setae, palpi longer than galea-lacinia, segment I longer than segment II. Labium (Fig. 24 a) with paraglossae with two nonpectinated blade-like setae (Fig. 24 b), segment II of palpi with a broad distomedial projection, segment III slightly longer than wide. Thorax yellowish brown, fore wing pads yellowish. Metanotum brownish. Legs (Fig. 25): femora yellowish, tibiae, tarsi and claws yellowish brown. Tarsal claws (Fig. 26) with 10–11 denticles. Pleurae yellowish brown, sterna pale yellow. Abdomen segments I–VI, IX–X (Fig. 2) yellowish, segments VII–VIII brownish. Posterior margin of terga with rounded spines (Fig. 27). Sterna pale yellow. Gills whitish (Fig. 28), rounded, subequal in length of each tergum, main trachea pigmented. Paraprocts as in Fig. 29. Caudal filaments yellowish (Fig. 30). Variation. some nymphs present the abdominal segments I–X yellowish (Fig. 3). Etymology. Churí-tepui is the name of the tepui from the Chimantá Massif where this species was collected. Diagnosis. Parakari churiensis n. sp. can be distinguished from the other species of the genus by the following combination of characters. In the nymph: 1) labrum (Fig. 19 a) dorsally with two subapical setae near midline, one short and one long; 2) left mandible (Fig. 20) with incisors positioned at obtuse angle to mola area; 3) right mandible with incisors elongated (Fig. 21 a), prostheca bifid basally (Fig. 21 b); 4) hypopharynx (Fig. 22) with lingua subequal in length to superlinguae; 5) maxillary palpi (Fig. 23 a) longer than galea-lacinia; 6) labial palpi (Fig. 24 a) with segment II with a broad distomedial projection; 7) posterior margin of abdominal terga with rounded spines (Fig. 27). In the adult, 1) thorax with medioscutum pale brown, submedioscutum brownish. Material. Holotype: male nymph: VENEZUELA, Bolívar Province, Chimantá Massif, Churí-tepui, Cueva Charles Brewer (the end), 17 / I/ 2009. T. Derka col. Paratypes: 34 nymphs the same locality and collector. 15 nymphs: spring stream below waterfall at Río Olinka originating in Cueva Juliana, 2300 m.a.s.l., Loc.8, 20/ I/ 2009, T. Derka col. 91 nymphs, 3 male and 12 female imagos (dried and damaged from spider web) and 2 male and 3 female subimagos: Quebrada Lila, a stream at the Plateau above Cueva Charles Brewer, 2400 m.a.s.l., Loc. 6, 26/ I/ 2009, T. Derka col. 132 nymphs, 10 female and 8 male subimagos (reared), 1 male imago (reared): Cueva Charles Brewer (entrance), 2300 m.a.s.l., 15 / I/ 2009, T. Derka col. 62 nymphs and 2 male imagos (reared): Quebrada Lila, a stream at the Plateau above Cueva Charles Brewer, 2400 m.a.s.l., Loc. 6, 21/ I/ 2009, T. Derka col. 52 nymphs: stream above Pozo Capuchino, 2300 m.a.s.l., Loc. 7, 16/ I/ 2009, T. Derka. 1 nymph: Río Olinka, stream above waterfall above Cueva Juliana, 2300 m.a.s.l., Loc. 11, 19/ I/ 2009, T. Derka col. 3 female imagos (dried and damaged from spider web), 7 male and 7 female subimagos: Canyon below Cueva Charles Brewer, 28 / I/ 2009, T. Derka col. 1 nymph: springs of Western river, Loc. 13, 23/ I/ 2009, T. Derka col. 55 nymphs: river below Cueva Juliana, ca. 2300 m.a.s.l., Loc. 9, 20/ I/ 2009, T. Derka col. 1 nymph: Cueva Colibrí, 26 / I/ 2009. Holotype and 63 paratypes are housed at IML; 20 paratypes housed at MIZA; other paratypes are housed at FNS. Biology. All material was collected in streams at tepuis plateaus (Figs. 31, 33 – 35). The only exception was material from the stream below Salto Angel (Fig. 32), the highest waterfall on the Earth (979 m), which drops down directly from the plateau of Auyán tepui. The material was collected from different types of streams, from spring streams to bigger mountain rivers. All streams are typically oligotrophic, with low conductivity from 9 to 18 μS.cm- 2 and acid water with pH ranging between 3.75 and 4.58 (Table 1). Streams have mostly bedrock bottom with only minor accumulations of sands, gravels, stones and detritus. Due to geological conditions, nymphs must be able to withstand high current velocities and fluctuations without possibility to hide into hyporheal. Nymphs inhabit environments with wide range of temperatures from oligostenothermal cave streams with stable temperatures around 13–14 ºC to wide and shallow streams with high daily thermal fluctuations with maximum temperatures exceeding more then 21 ºC during sunny days. Subimagos were observed flying one hour before sunset. Potential predators of nymphs are dragonfly and dobsonfly larvae. Curiously, some nymphs of P. churiensis were found in bladder tramps of Utricularia humboldtii (T.D. pers. observ.).Published as part of Nieto, Carolina & Derka, Tomáš, 2011, Parakari a New Genus of the Family Baetidae (Insecta: Ephemeroptera) from Guyana Highlands, pp. 47-59 in Zootaxa 3032 on pages 52-58, DOI: 10.5281/zenodo.20677