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The flat mite genus Raoiella Hirst (Tenuipalpidae) has attracted considerable research interest due to the rapid spread of Raoiella indica Hirst which feeds most commonly on species of palms (Arecaceae). Raoiella are frequently observed with their stylets inserted into the leaf stomatal openings, suggesting they feed on this site. Herein, we use transmission electron microscopy (TEM), scanning electron microscopy (SEM), low temperature scanning electron microscopy (LTSEM) and light microscopy (LM) to describe the mouthpart organization and the feeding behavior found in R. indica and R. bauchani Beard & Ochoa. The feeding mechanism is also discussed based on their distinctive morphological aspects. The structure of the gnathosoma of Raoiella generally agrees with the organization previously observed in Brevipalpus and Cenopalpus. As in other tetranychoid mites, there is no anatomical connection between the inter-stylet tube and the food channel, corroborating the theory that the stylets are used to pierce plant tissue (and assumedly inject saliva) but play no role in sucking up fluid from damaged host cells. As in Brevipalpus, the adoral setae are mechanoreceptors that may help guide the mite to the site for feeding. The ultrastructure of supracoxal setae e remains enigmatic. We also present observations of possible epidermal feeding on Phoenix roebelenii O'Brien (Arecaceae) for R. indica. Raoiella indica were shown to penetrate both the guard cells of the stomata and the epidermis of P. roebelenii, suggesting that feeding via the epidermis could be possible on this host plant. [ABSTRACT FROM AUTHOR]

The single known specimen of the monotypic genus CaenonychusOudemans, 1902 was examined. No distinguishing characters could be found to justify the retention of SpeleorchestesTrägårdh, 1909 as a separate genus from Caenonychus. Grandjean (1939) suspected these genera were synonymous but retained Speleorchestes as valid because of a difference between the two genera in opisthosomal shape. An artifactual explanation for the difference in opisthosomal shape is herein accepted based on the effects of applying different pressures to the coverslip over the same specimen. Therefore, Speleorchestes is treated as a junior synonym of Caenonychus. [ABSTRACT FROM AUTHOR]

Current and future legislation requiring the reduction of pesticides use, coupled with global initiatives for the promotion of soil health and conservation of soil biodiversity are creating opportunities for studies aimed at highlighting ecosystem services provided by functioning soil food webs in agricultural systems, including soil predatory mites. However, the key personnel for performing such studies are expert taxonomists, who are already spread very thin. To meet this demand, we propose an integrative approach where scientists (without expertise in taxonomy) play a significant role in supporting expert taxonomists. Soil samples were collected at the USDA ARS Farming Systems Project (FSP) at the Beltsville Agricultural Research Center, either incubated or not, followed by extraction of mites and nematodes. Improved modified Berlese funnels and an extraction protocol were utilized to improve sequencing success. Incubation dramatically enhanced the number of extracted individuals per sample whilst the daily freezing of extracted mites substantially improved the sequencing success rate compared to previous studies. Taken together, this led to the addition of records for eight Mesostigmata and ten Oribatida BINs to BOLD (Barcode of Life Datasystem). Fifteen species of Mesostigmata species were found, with three dominant species, Cycetogamasus diviortus (Athias-Henriot, 1967) (Parasitidae), Lasioseius youcefiAthias-Henriot 1959 (Blattisociidae) and a new species of Gamasellodes (Ascidae). LTSEM imaging followed by molecular identification contributed further details to the published descriptions of C. diviortus and L. youcefi. In line with our general aim, collecting, extracting, identification to morpho-species, sample preparation for DNA barcoding and uploading relevant information to BOLD was performed by trained personnel, but without taxonomic expertise. Whereas our skilled taxonomists focused on the morphological identifications using light microscopy, expanding on existing descriptions using LTSEM images and in a subsequent manuscript the description of a new species. We believe this division of tasks and labor will set the stage for further collaborative integrated studies between ecologists, biocontrol specialists and expert taxonomists for the identification, evaluation, and description of known and novel soil acarine biological control agents (BCAs). [ABSTRACT FROM AUTHOR]

Gamasellodes garybauchani sp. nov. Rueda-Ramírez & Santos is described based on specimens collected at the Beltsville Agricultural Research Center (BARC) (Maryland, USA). Twenty-one specimens were used for the description, of which five were subjected to low temperature scanning electron microscopy (LTSEM), followed by DNA extraction for genetic analysis and subsequent slide mounting. The remaining 16 specimens were subjected to only DNA extraction for genetic analysis and subsequent slide mounting. Morphological characters of the new species observed both in the images obtained in LTSEM and in the observation of the mounted specimens are detailed. Molecular information available on the Barcode of Life Datasysetm (BOLD) is presented. An update to the recent key to the Gamasellodes species is provided. [ABSTRACT FROM AUTHOR]

The family Tarsonemidae (Acari: Prostigmata) exhibits a high diversity of feeding habits and morphological structures, which allow them to be successful in many habitats. In Costa Rica, the Mesoamerican forest is a biome that includes all tropical and subtropical natural plant formations with high biodiversity. In Brazil, Theobroma cacao L. (Malvaceae) is cultivated under the canopies of larger trees, in a shaded plantation system called cabruca. Two new Metatarsonemus species are described from Brazilian cabruca agroforest. New records for the genus from Mesoamerica, Atlantic Forest and cabruca agroforest are presented. A key to the species of Metatarsonemus of the world is included. [ABSTRACT FROM AUTHOR]

The Tarsonemidae (Acari: Prostigmata) exhibit a high diversity of feeding habits and morphological structures, which allow them to live in a diversity of habitats. Tarsonemus is the largest genus, with more than 280 described species belonging to three subgenera: Tarsonemus sensu stricto, Chaetotarsonemus and Schaarschmidtia. Eight species of the genus have been reported from Brazil. In addition, there are two new species, Tarsonemus cacaosp. nov. from Theobroma cacao L. (Malvaceae) branches, and Tarsonemus bahiensissp. nov. from Passiflora foetida L. (Passifloraceae) and Etlingera elatior Jack (Zingiberaceae) leaves. Both new species were collected in a cabruca agroforest, a traditional cacao cultivation system in the southern coast region of Bahia state. The new Tarsonemidae are described and illustrated here. Pharyngeal and gnathosomal structures of the new species are compared to other Tarsonemus species. [ABSTRACT FROM AUTHOR]