Ekaterina A. Sidorchuk

Plant-feeding mite diversity in Triassic amber (Acari: Tetrapodili)

Carnian-aged amber (c. 230 Ma) from north-eastern Italy contains the first pre-Cretaceous inclusions of arthropods, plant remains and microorganisms. Here, we report further recovery of mites from this Late Triassic amber, supporting the prediction of a diversity of arthropods to be found in this oldest known fossiliferous resin. Two new genera and species of the Tetrapodili lineage, Minyacarus aderces and Cheirolepidoptus dolomiticus, are described. They indicate, along with the two previously described taxa of these mites, Triasacarus fedelei and Ampezzoa triassica, from the same source, a quite flourishing group of already highly specialized, four-legged, phytophagous mites in those remote times. The diversity of character states found in these Triassic mites challenges some conceptions of polarities inferred from modern four-legged mites. A hierarchical distinction is made between the Tetrapodili as a higher category of mites, and two constituent superfamilies, the Eriophyoidea embracing c. 300 extant genera and 3500 species, and the new superfamily Triasacaroidea, accommodating the four Triassic taxa. Varied forms and sizes of bodies and mouthparts amongst these Triassic mites indicate different feeding strategies in adapting to specialize on the same host plant of the Cheirolepidiaceae, for which we first report entire shoots from this amber outcrop. The cheliceral stylets of Triasacaroidea are generally blunt, indicating that, unlike extant Eriophyoidea, they were less able to pierce surface plant cells. Rather, we suggest that they may have fed on mesophyll cells by access through leaf stomata, whose density and appropriate dimensions are revealed by our study of plant cuticles. Further findings of small arthropods from this source of amber are increasingly probable and of great potential interest in adding knowledge about their early evolution. http://zoobank.org/urn:lsid:zoobank.org:pub:279BE1F3-8667-48D9-BEE8-F7F22C5DEF7D

Redescription of the mite Glaesacarus rhombeus (Koch & Berendt, 1854) from Baltic amber (Upper Eocene): evidence for female-controlled mating

Glaesacarus rhombeus (= Acarus rhombeus Koch & Berendt, 1854) from the Upper Eocene Baltic amber is the oldest known fossil of Astigmata, and therefore is important for calibrating the molecular clock for mite phylogenies and inferring the direction of character state changes in phylogenetic analyses. Based on the imprecise original description, it has been included in five different families of astigmatan and non-astigmatan mites. Using a novel method of sample preparation, we provide a detailed taxonomic characterization of G. rhombeus based on the type material and many additional specimens. We show that G. rhombeus belongs to a unique, previously unknown lineage of astigmatan mites (Glaesacarus gen. nov. and Glaesacaridae fam. nov.). The family Glaesacaridae does not have any close recent relatives, although some apomorphies or presumed apomorphies indicate that it may be distantly related to the extant family Lemanniellidae. Morphological evidence found in Glaesacaridae further challenges the current concept of the superfamily ‘Canestrinioidea’, an assemblage including Canestriniidae, Heterocoptidae, and Lemanniellidae, and calls for the exclusion of the two latter taxa from this superfamily. Furthermore, we show that the authorship of Sarcoptidae, one of the families in which G. rhombeus was placed historically, should be Berendt (1845). The terminal hysterosoma of G. rhombeus females has a unique, pad-like organ, resembling several structures found in males of many Astigmata that are used to hold the female during copulation. An exceptionally well-preserved copulating pair of G. rhombeus provides insights into the functional morphology of this organ, which apparently was used by the female to cling to the male during mating, suggesting that females assumed the active role during mating and have partial or complete control over copulation. This reversal of the stereotypic sex roles is a very rare example among animals performing direct insemination.

Three new species of oribatid mites (Acari: Oribatida: Galumnoidea) from Ethiopia

ABSTRACT Three new species of oribatid mites of the superfamily Galumnoidea, Galumna lanceosensilla n. sp., Trichogalumna africana n. sp. (both Galumnidae), and Galumnopsis giganteus n. sp. (Galumnellidae), are proposed and described. All new species were collected in soil from Bale Mountains National Park of Southern Ethiopia.

A new species of Dolicheremaeus (Acari: Oribatida: Tetracondylidae) from Ethiopia

Abstract The oribatid mite genus Dolicheremaeus comprises more than 160 species. We describe a new species, Dolicheremaeus aethiopicus sp. nov., collected in soil from Bale Mountains National Park (African region, Ethiopia). This new species differs from other species by a combination of the length of prodorsal setae; morphology of rostral setae and sensilli; morphology and number of notogastral condyles and the morphology of the notogastral setae; number of epimeral setae; and the morphology of leg setae u.

A new species of the genus Pergalumna (Acari: Oribatida: Galumnidae) collected in moss on trees from Ethiopia

Abstract The oribatid mite genus Pergalumna Grandjean, 1936 (Acari: Oribatida: Galumnidae) comprises 111 species. We describe the species Pergalumna makarovae sp. nov., collected in moss on trees from Bale Mountains National Park (southern Ethiopia). The new species is distinguishable from other species of Pergalumna by the presence of the following character states in combination: smooth surface of body, clavate sensilli, minute interlamellar setae, three pairs of rounded notogastral areae porosae and complete dorsosejugal suture.

Morphology of Juvenile Stages of Pedrocortesella africana Pletzen, 1963 and Aleurodamaeus africanus Mahunka, 1984 (Acari: Oribatida)

Abstract. The morphology of juvenile stages of the oribatid mites Pedrocortesella africana Pletzen, 1963 and Aleurodamaeus africanus Mahunka, 1984 is described and illustrated. The juveniles of Pedrocortesella africana are characterized by: cuticle with reticular ornamentation and folds; body with microgranular cerotegument; prodorsal setae leaf-shaped, sensilli petiolate, tuberculate blades with a rounded distal margin; gastronotic region flat; larva and nymphs with nine pairs of leaf-shaped gastronotic setae; scalps folded, larval scalp with seven pairs of setae, nymphal scalps with six pairs of setae; leg famulus sunken. The juveniles of Aleurodamaeus africanus are characterized by: cuticle smooth; body with filamentous cerotegument and with very not numerous granules; prodorsal setae setiform (except short interlamellar setae in nymphs); gastronotic region convex in lateral aspect; larva and nymphs with 12 of setiform gastronotic setae; scalps with reticular ornamentation, larval scalp with nine pairs of setae, nymphal scalps with ten pairs of setae; leg famulus emergent. The comparative analysis between known juveniles in Plateremaeoidea and Gymnodamaeoidea are given.

A new fossil mite from French Cretaceous amber (Acari: Heterostigmata: Nasutiacaroidea superfam. nov.), testing evolutionary concepts within the Eleutherengona (Acariformes)

We describe a fossil member of Heterostigmata of Late Cretaceous age that is the first to show an unexpected array of primitive and derived attributes, some of which are perplexing for a member of this specialized group of trombidiform mites. In contrast, previously published records of heterostigmatic mites of similar age have been of fossils readily classified within moderately derivative superfamilies of this clade. With remarkably preserved details visible, our fossil is a male, from amber of Early Santonian to Middle Cenomanian age (c.85–97 Ma), from a deposit in the Department of Vendée in north-western France. A new genus and species, Nasutiacarus perplexus Sidorchuk & Lindquist, representing a new family and superfamily, are described. We discuss the most salient of the perplexing attributes, especially aspects of the gnathosoma, using them to emphasize the significance of parallel and convergent evolution amongst major groups of eleutherengone Trombidiformes. http://zoobank.org/urn:lsid:zoobank.org:pub:F6CF7838-126F-4196-BE38-77791299240E

A new species of Separatoppia (Acari: Oribatida: Oppiidae) from Ethiopia

Abstract The oribatid mite genus Separatoppia currently comprises four previously described species. We describe a new species, Separatoppia horvathae sp. nov., collected from soil in the Harenna forest within the Bale Mountains National Park (southeastern Ethiopia). This new species differs from its congeners by the extremely long sensilli. We present the first description of the ovipositor, gnathosoma and leg setation and solenidia of a Separatoppia species.

MORPHOLOGY OF JUVENILE STAGES OF METABELBA GLABRISETA MAHUNKA, 1982 AND DAMAEUS AURITUS KOCH, 1835 (ACARI: ORIBATIDA: DAMAEIDAE)

Abstract. The morphology of juvenile stages of the oribatid mites Metabelba glabriseta Mahunka, 1982 and Damaeus auritus Koch, 1835 (Damaeidae) is described and illustrated. The juveniles of Metabelba glabriseta are characterized by: cuticle smooth, with rare folds and also with slightly developed reticulate ornamentation dorso-laterally; cerotegument of body with conical or strongly oblong granules, that of some body setae cloud-like; rostral and lamellar setae of approximately identical length, with hardly developed barbs; sensilli with long flagellate tips, smooth; gastronotic region rounded posteriorly; almost all gastronotic setae with small flagellate tips, barbed, setae lp longest in larva, setae c1, c2, h1 longest in nymphs; cornicle k of nymphs long, slightly curled, distally slightly swollen and longitudinally split; all legs of juveniles shorter than body; setae d and v” on trochanter III appear in adult; famulus emergent. The juveniles of Damaeus auritus are characterized by: cuticle smooth, with rare folds; cerotegument of body with spherical granules, body setae without cerotegument; prodorsal setae barbed, setae ex and larval setae in short, strong, sensilli thickened, but with thin, bent tips; gastronotic region truncate (in larva) or rounded (in nymphs) posteriorly; some gastronotic setae vane-like; cornicle k of nymphs short, strong, conical; all legs (except II in nymphs) of juveniles longer than body. Famulus sunken. Juveniles are compared among the known species of Metabelba and Damaeus, and also among the genera Metabelba, Damaeus and Epidamaeus.

Two new species of Austrocarabodes (Uluguroides) from Ethiopia (Acari: Oribatida: Carabodidae).

Abstract. Two new species of oribatid mites of the subgenus Austrocarabodes (Uluguroides), A. (U.) arboreus sp. nov. and A (U.) aethiopicus sp. nov., are described from Ethiopia. The former species was obtained in mosses on trees from Cholomu Forest (10 km to the south from Ginchi city); the second species was obtained from soil from Harenna Forest (Bale Mountains National Park). Both new species differ from all known species of the subgenus by presence of eight to nine pairs of genital setae (five-six in other species). A diagnostic key to African species of Austrocarabodes (Uluguroides) is presented.