Gastronotal Setae Research Articles

Morphological ontogeny of Conoppia palmicincta (Acari, Oribatida, Cepheusidae)

The morphological ontogeny of Conoppia palmicincta (Michael, 1880) is described and illustrated. The adult of this species is poorly known, but the tritonymph is relatively well known as one of the most beautiful oribatid mites. The juveniles of this species are light brown, roundish and flattened. Most prodorsal setae of the juveniles are setiform (short ro, le and ex; long bs), except for phylliform and reticulate in. The larva has 11 pairs of gastronotal setae, including h2, the nymphs have 12 pairs (h3 and p-series are added, and d-series is lost). Most gastronotal setae of juveniles are wide, phylliform, reticulate and occupy the marginal parts of gastronotum, except for five setiform setae in the larva (very long c3 and h1, medium sized h2 and short da and dm), and four setiform setae in the nymphs (very long c3 and h2, long p2 and shorter p3). The nymphs are eupheredermous, i.e. they lose their dorsal seta of d-series and carry the exuvial scalps of previous instars on the gastronotum. Most leg setae of juveniles are setiform, except for three wide, phylliform setae on leg I of larva (l on genu and l’ on tibia), from which l’’ on genu is reticulate, while l’ on genu and tibia has longitudinal lines. Relatively long are seta l’’ on tibia I of larva, and l’’ on tibia I and II of the nymphs. Seta d accompanies solenidion σ on genua I–III and φ on tibiae II–IV.

Ontogenetic instars of Basilobelba werneri Mahunka, 1982 (Acari, Oribatida, Basilobelbidae)

Basilobelba werneri (Oribatida, Basilobelbidae) was collected from an alpine cloud forest in Guatemala. This is the first representative of the family Basilobelbidae in the Guatemalan fauna. A supplementary description of adult B. werneri is presented along with summarized diagnostic morphological traits. The juvenile instars of B. werneri are described for the first time. The larva is characterized by the presence of 11 pairs of gastronotic setae, of which c1 (short), da and dm (medium-sized) slightly thickened, barbed, la, lm, lp, h1, and h2 long, thick, narrowed distally, heavily barbed, and c2, c3 and h3 short, setiform, roughened. The proto-, deuto- and tritonymph are characterized by the presence of 12 pairs of short, setiform gastronotic setae.

Description of juvenile instars of Scapheremaeus tonatiuh Palacios-Vargas, Ríos & Vázquez, 1998 (Acari, Oribatida, Cymbaeremaeidae)

The oribatid mite species Scapheremaeus tonatiuh (Oribatida, Cymbaeremaeidae) is recorded for the first time in the U.S.A. (initially described from Mexico). Its juvenile instars are described, based on materials collected from arboreal habitats in Florida, U.S.A. (Neotropical region). The larval instar is characterized by the presence of gastronotic setae с3, la, lm, lp long, lanceolate having setiform apex, and h1 very long, subflagellate; the nymphal instars are characterized by the presence of exuvial scalps, 12 pairs of gastronotic setae (da, dm, dp absent) of which setae с3, la, lm, lp, h1, h2 are long, phylliform but h3 is very long, subflagellate. The main morphological traits of the adult are summarized.

Morphological ontogeny of Oribatula pannonica (Acari, Oribatida, Oribatulidae), and comments on some species of Oribatula Berlese

The morphological ontogeny of Oribatula pannonica Willmann, 1949 is described and illustrated. Most prodorsal setae of juveniles are of medium size, and bothridial seta is clavate. The larva has 11 pairs of gastronotal setae, including h2, most are of medium size and barbed, nymphs have 13 pairs (p3 absent), of which most are short and smooth. Basal excentrosclerites are present at nine pairs of gastronotal setae (c1, c2, d-, l-series, h1) in the larva, and at 12 pairs (c1, c2, d-, l-, h-series, p1) in the nymphs. The morphology of adult O. pannonica is compared with congeners with 13 pairs or an unknown number of notogastral setae.

Morphological Ontogeny, Ecology, and Biogeography of Fuscozetes fuscipes (Acari, Oribatida, Ceratozetidae).

The systematic status of Fuscozetes Sellnick, 1928, is not clear in the literature. Therefore, the morphological ontogeny of F. fuscipes (C.L. Koch, 1844), the type species of this genus, was investigated and compared with its congeners in this study, and a new diagnosis of Fuscozetes is given. The juveniles of F. fuscipes are light brown, with a brown prodorsum, sclerites, epimeres, and legs. In all juveniles, a humeral organ and a humeral macrosclerite are present. The gastronotum of the larva has 12 pairs of setae (h3 is present), whereas the nymphs have 15 pairs. In the larva, the gastronotal shield is weakly developed, and most gastronotal setae are short except for a slightly longer h2. Most of the gastronotal setae are inserted on the microsclerites except for h3, and several other macrosclerites and many microsclerites are present on the hysterosoma. In the nymphs, the gastronotal shield is well developed, with 10 pairs of setae (d-, l-, and h-series, and p1), and setae p2 and p3 are located on a large posteroventral macrosclerite. In all the instars, femora I and II are oval in cross-section, without a large ventral carina. Mitochondrial COI sequence data revealed a deep split between the Nearctic and Palearctic populations of F. fuscipes, and a less, but significant, divergence within each continent. These strong geographical barriers were contrasted with multiple cases of shared haplotypes over long distances in the Palearctic, indicating high migration rates in modern times.

Morphological Ontogeny and Ecology of a Common Peatland Mite, Nanhermannia coronata (Acari, Oribatida, Nanhermanniidae).

Nanhermannia coronata Berlese, 1913, is a common and abundant oribatid species in peatlands but can be easily mistaken for N. sellnicki Forsslund, 1958, as an adult. Therefore, the identity of adults of N. coronata from several sites in Norway and Ireland was supported by the COI sequence data, and based on this material, the morphological ontogeny of this species is described and illustrated to highlight the differences between N. coronata and N. sellnicki. In all juvenile stages of N. coronata, the bothridial seta is absent, but two pairs of exobothridial setae are present, including short exp and exa reduced to its alveolus. In the larva, seta f1 is setiform, but in the nymphs, it is reduced to its alveolus. Most prodorsal and gastronotal setae of larva are short, and of nymphs they are long. In all instars, the leg segments are oval in cross section and relatively thick, and many setae on tarsi are relatively short, thick and conical, except for longer apical setae. Seta d accompanies solenidion σ on all genua, φ1 on tibia I and φ on other tibiae. We found some morphological characters that clearly differentiate N. coronata from N. sellnicki, like the number of setae on femora of adults and tritonymphs, the shape of insertions of prodorsal seta in and all gastronotal and adanal setae of juveniles; in N. sellnicki, these setae are inserted in small individual depressions, whereas in N. coronata, these depressions are absent. Our ecological observations confirm a common occurrence of N. coronata in raised bogs, a high percentage of juvenile stages in its populations and a preference of this species for humid microhabitats, whereas N. sellnicki is less common than N. coronata and occurs in drier habitats.

Ontogenetic instars of Zygoribatula excavata, with remarks on juveniles of Oripodoidea (Acari: Oribatida)

Information on the morphological ontogeny of oribatid mites of the family Oribatulidae is very scarce, and the juveniles of most species are unknown yet. In this work, the ontogenetic instars of the semicosmopolitan species, Zygoribatula excavata Berlese, 1916 are studied. The juvenile instars of this species are morphologically similar to those of the other species of Zygoribatula, and this genus can be included among those in which species are difficult to distinguish based on juvenile characteristics alone. As information on the morphological ontogeny of most species of Oribatulidae is still insufficient or unknown, a comparison on the juvenile characteristics of the families belonging to the superfamily Oripodoidea is given based on our own data and available literature sources. The major characteristics of juvenile instars of 10 families and 21 genera are presented. There are few characters, such as body shape and size, pattern of cuticle, excentrosclerites at gastronotic setae, size and morphology of setiform organs, such as bothridial as well as gastronotic setae that distinguish the families or genera of Oripodoidea.

Morphological ontogeny of Nanhermannia sellnicki (Acari, Oribatida, Nanhermanniidae), and comments on Nanhermannia Berlese.

The morphological ontogeny of Nanhermannia sellnicki Forsslund, 1958 is described and illustrated. In all juvenile stages the bothridial seta is minute, and two pairs of exobothridial setae are present (exa reduced to its alveolus, exp short). In the larva, the seta f1 is setiform but in the nymphs it is unobservable among cuticular tubercles. Most prodorsal and gastronotal setae of the larva are short while thouse of nymphs are long; seta in and all gastronotal and adanal setae are inserted in small individual depressions. In all instars the leg segments are oval in cross section and relatively thick, and most setae on tarsi are relatively short, thick or conical. The seta d accompanies solenidion on all genua, 1 on tibia I and on other tibiae.

Morphological ontogeny of Zachvatkinibates svanhovdi (Acari, Oribatida, Punctoribatidae).

The morphological ontogeny of Zachvatkinibates svanhovdi A. Seniczak & S. Seniczak, 2023 is described and illustrated. The juveniles of this species are light brown with slightly darker colour on the prodorsum, gastronotal shield, surrounding of gla opening, and legs. The larva has 12 pairs of gastronotal setae, most are of medium size and barbed; the nymphs have 15 pairs, most are short and smooth. In all juveniles, the setae of c-series are inserted on unsclerotized integument. In the larva, the pygidial shield is absent but, in the nymphs, the gastronotal shield is present and the setae p2 and p3 are inserted on unsclerotized integument. In the larva, a humeral organ is absent but is present in the nymphs.

Morphological ontogeny of Oribatula heterochaeta (Acari, Oribatida, Oribatulidae), with comments on some species of Oribatula Berlese.

The morphological ontogeny of Oribatula heterochaeta (Feider et al., 1970) is described and illustrated. The larva of this species has 12 pairs of gastronotal setae including h3 and the nymphs have 15 pairs; most are of medium size and barbed except for short and smooth h3 in the larva and p3 in the protonymph and deutonymph. In the larva, the excentrosclerites are present at four pairs of gastronotal setae (c2, la, lp, h1), and in the nymphs at seven pairs (c2, la, lp, h-series, p1). Comparisons of known morphological ontogeny of species in Oribatula are given.

Morphological ontogeny of Carinogalumna erciyesi sp. nov. (Acari, Oribatida, Galumnidae) from Turkey, with comments on Carinogalumna Engelbrecht.

The morphological ontogeny of Carinogalumna erciyesi sp. nov. from Turkey is described and illustrated. The adult of this species is most similar to that of C. montana Engelbrecht, 1973 but differs from it mainly by the shape of the bothridial seta and porose areas Aa and A2. The larva of C. erciyesi has 12 pairs of gastronotal setae, including alveolar h3, nymphs have 15 pairs; most setae are of medium size and barbed, except for short p2 and p3, smooth in protonymph; setae p2 and p3 are inserted on unsclerotized integument. In all juveniles the bothridial seta is clavate with long, narrow, barbed head. The gastronotal shield is well-developed with setae of d-, l-series and h1 in the larva, and of d-, l-, h-series and p1 in the nymphs. Setae of c-series of juveniles are inserted on microsclerites, and genital opening is placed on a large sclerite. In all juveniles a humeral organ is present, with porose area above it.

Morphological ontogeny of Eubelba danubedeltaica sp. nov. (Acari, Oribatida, Damaeidae) and comments on Eubelba Miko

The morphological ontogeny of Eubelba danubedeltaica sp. nov. is described and illustrated. The adult of E. danubedeltaica is most similar to E. sculpta (Mihelčič, 1957) which differs from E. danubedeltaica by the presence of tubercle E2p, slightly longer seta c1 and leg IV, and thicker and clearly barbed epimeral, genital, aggenital and anal setae whereas in E. danubedeltaica tubercle E2p is absent and these setae are thinner and most are smooth, except for finely barbed genital and anal setae that are clearly visible at a high SEM magnification. In the juveniles of E. danubedeltaica, most prodorsal setae are of medium size, except for short seta in in the nymphs and very long setiform bothridial seta which are strongly curved in the distal part. Most gastronotal setae of juveniles are long, or very long, except for medium-sized c3, la, lm and h2, and short h3 in the larva, and medium-sized c3 and p2 in nymphs. The nymphs are quadrideficient and eupheredermous, i.e. they have lost the d-series setae and carry the exuvial scalps of previous instars using a cornicle located between setal pair h3. In all juveniles, the famulus ɛ on tarsus I is sunken but is emergent in the adult. Seta d accompanies solenidion σ on genua I–III and φ on tibiae II–IV.

Morphological ontogeny of Pilogalumna ayildizi sp. nov. (Acari, Oribatida, Galumnidae), a new cryptic species from Turkey

The morphological ontogeny of Pilogalumna ayildizi sp. nov. is described and illustrated. This species is similar to P. tenuiclava (Berlese, 1908) as adult, but differs from it clearly by the morphology of juvenile stages and ecology. The larva of P. ayildizi has 12 pairs of gastronotal setae, most are short and smooth except for slightly longer dp and medium-sized c-series, h1 and h2, and minute h3, and the nymphs have 15 pairs of these setae, most are short and smooth except for medium-sized and barbed c-series. The gastronotal shield of juveniles is poorly developed with setae of d-, l-series and h1 in the larva, and d-, l-, h-series and p1 in the nymphs. In the juveniles setae of c-series, p2 and p3 have basal microsclerites, and a humeral organ is present.

Morphological ontogeny of Amerobelba decedens (Acari, Oribatida, Amerobelbidae)

The morphological ontogeny of Amerobelba decedens Berlese, 1908 is described and illustrated. In the adult of this species, the bothridial seta is setiform, unilaterally ciliate, notogastral setae are short and barbed, and sexual dimorphism is present on tarsus IV. Most prodorsal setae of juveniles are short and smooth, except for medium-sized ro, barbed in the nymphs. The bothridial seta is long, setiform and barbed in distal part. The gastronotal setae are of medium size and barbed, except for smooth c1 and c2 in all juveniles, and smooth of d-series and short h2 in the larva. Setae c1 and c2 are inserted on large macrosclerite, and other gastronotal setae are inserted on individual microsclerites, except for h2 in the larva. The anal and anogenital regions are reticulate, and adanal setae are inserted on individual microsclerites. The nymphs are quadrideficient and eupheredermous, i.e. they lose setae of d-series and carry the exuvial scalps of previous instars. In this species, seta d accompanies solenidion σ on genu III and φ on tibia III and IV, both in the juveniles and adults. It is a xero-thermophilous species, with one generation per year.

Ontogenetic instars of the oribatid mite Scheloribates arsizonensis n. sp. (Acari, Oribatida, Scheloribatidae) from Ethiopia

A new species of the genus Scheloribates (Oribatida, Scheloribatidae) — S. (Scheloribates) arsizonensis n. sp. — is described from Ethiopia, based on adult and juvenile instars, collected from litter and green moss in Arsi Mountains National Park. Adults of the new species differ from S. praestantissimus praestantissimus (Berlese, 1916) in having fusiform, distally pointed bothridial seta, the absence of prolamella, and the presence of well-developed notogastral setae p<sub>1</sub>. The comparison of juveniles of the new species with juveniles of other Scheloribates species is presented. Juveniles of the new species can be distinguished from the other known juveniles of S. (Scheloribates) by the presence of two strong, long, longitudinal, dorsolateral folds on the gastronotum in all instars, long gastronotic seta c<sub>3</sub>, which is distinctly longer than other gastronotic setae in nymphal instars, the presence of vestigial gastronotic seta h<sub>3</sub> in larva, and in the absence of aggenital setae in deutonymph.

Morphological ontogeny of Pilogalumna kazakhstanica sp. nov. (Acari, Oribatida, Galumnidae) from Kazakhstan

The morphological ontogeny of Pilogalumna kazakhstanica sp. nov. from Kazakhstan is described and illustrated. The adult stage of this species is most similar to P. ornatula Grandjean, 1956, but differs from it mainly by slightly smaller body size and by having two postanal porose areas, whereas P. ornatula has usually a single porose area. In P. kazakhstanica the prodorsal porose area Ad and all notogastral porose areas are framed by dark brown integument, whereas in P. ornatula framed is usually porose area A1. The larva of P. kazakhstanica has 12 pairs of gastronotal setae, most are short and smooth, except for medium-sized and barbed c2, c3, h1 and h2, and minute, smooth h3, the nymphs have 15 pairs, most are short and smooth, except for medium-sized and barbed c2 and c3. In the juvenile instars the gastronotal shield is poorly developed, bearing setae of d-, l-series and h1 in the larva, and setae of d-, l-, h-series and p1 in the nymphs. In all juveniles, a humeral organ is present, and setae of c-, ad-series and p2 and p3 are with microsclerites.

Morphological ontogeny of Graptoppia granadaensis sp. nov. (Acari, Oribatida, Oppiidae), and comments on Graptoppia Balogh

The morphological ontogeny of Graptoppia granadaensis S. et A. Seniczak sp. nov. is described and illustrated, based on the instars obtained from laboratory cultures. The adults of this species were collected from spruce litter (Picea sp.) in the Campus of University of Science in Granada, Spain. These adults are the most similar to that of G. tanaitica Karppinen et Poltavskaja, 1990, but differ from it by having fewer spines on the bothridial seta. In laboratory cultures, G. granadaensis fed on deciduous and pine litter and small parts of pine cones, overgrown by mycelium. The juveniles of this species are unpigmented, with soft body, covered with microtuberculate cerotegument. The larva has 12 pairs of gastronotal setae, including h3, the nymphs have 15 pairs; all setae are smooth and mostly short. In the juveniles, seta d coupled to proper solenidia is present on genua I–III and tibiae II–IV.

Description of Oromurcia magadanensis sp. nov. (Acari, Oribatida, Ceratozetidae) from Russia, with remarks on biogeography of the genus Oromurcia Thor, 1930

Species of the genus Oromurcia Thor, 1930 (Oribatida, Ceratozetidae) mainly have an arctic or alpine distribution in the Western Palaearctic region and Greenland. We describe a new species of Oromurcia from Northeast Asia (Magadan Region, Russia) based on adult and juvenile instars. Numerous populations of Oromurcia magadanensis sp. nov. were found under arctic-alpine plants in a narrow stream gully with large snow accumulation on the Ola Plateau (1023 m a.s.l.). Adults of Oromurcia magadanensis sp. nov. differ from those of Oromurcia bicuspidata and O. sudetica by their smaller size, the presence of clavate, distally broadly rounded bothridial seta, tutorium with several teeth distally, and the absence of striations on the lamella. Juvenile instars of the new species differ from those of O. bicuspidata and O. sudetica by the presence of medium-sized gastronotic setae in the larva, and long lateral and posterior gastronotic setae in nymphs. We compare adult and juveniles of Oromurcia magadanensis sp. nov. with those of other members of the ceratozetid subfamily Trichoribatinae Shaldybina, 1966 from arctic or alpine regions, for which ontogeny is known, and provide revised diagnoses for adult and juvenile members of Trichoribatinae. All Oromurcia species are associated with cold wet places (periglacial habitats, bogs and fens, alpine meadows, snowbeds, and, less frequently, montane coniferous forests) in Eastern and Western Palaearctic, but they are absent from High Arctic and Siberian regions that are ultra-cold in winter. This spatial disjunction argues for a former Trans-Palaearctic range that was possibly subdivided by reсurrent cryo-arid Pleistocene episodes.

Morphological ontogeny of Phauloppia nemoralis (Acari, Oribatida, Oribatulidae), with comments on Phauloppia Berlese

The morphological ontogeny of Phauloppia nemoralis (Berlese, 1916) is described and illustrated. The adult of this species is most similar to Ph. incomperta (Pérez-Íñigo et Peña, 1996), but differs from it mainly by the shape of bothridial seta, porose areas Aa and A1, and location of porose area A1 and seta ad3. In the juveniles of Ph. nemoralis, the prodorsal setae ro, le and in are of medium size or long, ex is short, and the bothridial seta is of medium size and clavate, with barbed head. The larva has 12 pairs of gastronotal setae, the nymphs have 14 pairs; all are of medium size and barbed. In this species, the basal excentrosclerites occur, at setae c2, h1 and l-series in the larva, and c2, p1 and l- and h-series in the nymphs. In all nymphs, solenidion ω2 on tarsus I is longer and thinner than ω1, and seta ft'' is relatively long and located posterior to solenidion ω2.

Morphological ontogeny of Punctoribates ghilarovi (Acari, Oribatida, Punctoribatidae)

The morphological ontogeny of Punctoribates ghilarovi Shaldybina, 1969 is described and illustrated. This species is most similar to P. mundus Shaldybina, 1973, but is larger than the latter species. The juveniles of P. ghilarovi are light brown, with most prodorsal setae of medium size, except for long seta ro in the larva, and short and smooth seta ex in all instars. The larva has 12 pairs of gastronotal setae, including h3, the nymphs have 15 pairs. Most of them are medium sized and barbed, except for slightly longer dm, dp, lm, lp and h1, and short and smooth h3 in the larva, and short and smooth da and dm, slightly longer dp, and clearly longer h1, h3 and lp in the nymphs. In all juveniles, a humeral organ is present.