Two new species of Tarsonemus Canestrini & Fanzago, 1876—namely Tarsonemus bengalicus Karmakar & Bera sp. nov. and Tarsonemus kajuae Karmakar & Bera sp. nov.—are described and illustrated based on specimens collected on leaves of Bamboo, Bambusa vulgaris Schard. and Cashew, Anacardium occidentale L., respectively from Ramnagar, Purba Medinipur, West Bengal, India. Additionally, subgeneric diagnostic characters of Tarsonemus are compiled and a key to the Indian Tarsonemus species is also provided.

The two-spotted spider mite, Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae) causes significant problems in cotton fields. The pest has developed resistance to abamectin, which is used intensely against spider mite populations. A discriminating dose was applied to T. urticae populations collected from Aydın, Adana, Şanlıurfa, and Diyarbakır provinces between 2019 and 2021, where there is significant cotton production and intensive acaricide applications. Populations with a mortality rate of less than 80% at the discriminating dose applied to field populations were included in the bioassay study. Then, the 10 most resistant populations were determined based on their LC₅₀ and LC₉₀ values. It was observed that there was high resistance (HR) in two T. urticae populations collected from Diyarbakır (DIY28 and DIY2) with LC₅₀ values of 24.5 and 33.81 mg L^-1, respectively 113 and 156-fold and one population collected from the province of Aydın (AYD4) LC₅₀ value of 23.5 mg L^-1 and 109-fold. As a result of the comparisons with a susceptible population in biochemical studies, it was determined that the carboxylesterase (CarE) enzyme of these populations (except for SAN6, SAN7, SAN8, ADA9, and ADA11) had more than 2-fold higher activity compared to the glutathione enzyme (GST), and they were in statistically different groups. When the GST enzyme activities were examined, it was found that the enzyme activities were generally low, except for the ADA11 and ADA16 populations (3.73 and 2.3-fold). In terms of the target site resistance, it was observed that there was no target site mutation (G314D and I321T-G326E) in the glutamate-gated chloride channels (Units GluCl 1 and 3) in these highest 10 resistant populations. It can be said that the resistance levels determined for abamectin from the obtained populations were determined to be low. In brief, out of the total 44 populations brought in and tested, only 30 populations were considered resistant with a mortality rate below 80% after the applied discriminating dose. It was determined that 6.8% of these 30 populations had HR, 31.8% had medium resistance (MR), and 29.5% had low resistance (LR). When examining by regions, it was found that high resistance populations were more prevalent in Diyarbakır and Aydın (15.4% and 10%, respectively) provinces, while the highest percentage of MR populations was found in Şanlıurfa, at 90%. Abamectin still acts as an effective acaricide. However, it is recommended to use acaricides with different modes of action to prevent possible emergence of resistance cases.

A new mesostigmatic mite species, Antennseius (Vitzthumia) circumcaspius sp. nov., is described from Russia and Iran on the adult specimens. This soil-dwelling species populates different habitats (including coastal maritime and inner salty grasslands, forest and orchard soil-litter, and moss) in Kalmykia, Dagestan, Kazakhstan, and Iran. The new species is very close to Antennoseius oudemansi (Thor, 1930); A. janus Lindquist & Walter, 1989 (granulate form); and A. koroljevae Chelebiev, 1984. All these species compose together a natural group as designated by Chelebiev (1984). Idiosomal integument of most shields and soft cuticle of their adult is tuberculate-granulate. Females of these species are possessed the inversely trapezoidal opisthonotal shield with posterolateral margins usually emarginated; anal shield bearing only three circumanal setae. Map of records of oudemansi-group members in the Palaearctic and key for their female identification are given.

In this study, we aimed to describe the morphological and molecular characteristics of Austroglycyphagus geniculatus (Acari: Glycyphagidae) breeding in fodder. Flour and corn-crushed fodder samples were collected from a small fodder processing mill in Wuhu, Anhui province, China. The detection rate of A. geniculatus was 100% in six samples, and the breeding density was 1.44 mites/g. Under an optical microscope, we observed that the mite body was oval and small in size. The epidermis of the mite was coated with fine particles. We found two obvious, large, and red lateral ventral glands on either side of hysterosoma. The gene sequences for internal transcribed spacer (ITS) and mitochondrial cytochrome oxidase 1 (COX 1) of A. geniculatus were amplified and uploaded to the GenBank nucleotide sequence database. To the best of our knowledge, this is the first study to report the detailed description of the morphological and molecular characteristics of A. geniculatus. The results of phylogenetic relationships obtained from the ITS and COX 1 support the classification statuses of A. geniculatus to the family Glycyphagidae based on the morphological classification. Our study provides morphological and molecular data for inferring phylogenetic relationship of A. geniculatus.

Five new species of Pavania (Acari: Heterostigmata: Dolichocybidae) phoretic on scarab beetles (Coleoptera: Scarabaeidae) are described: P. eurysternophila sp. nov. collected on Eurysternus cyclops and E. caribaeus in French Guiana and Brazil; P. tenuiseta sp. nov. on Canthon sp. in French Guiana; P. nicaraguaiensis sp. nov. on Canthon deyrollei in Nicaragua; P. brevisetosa sp. nov. on Canthon humectus in Mexico; and P. lancetosetosa sp. nov. on Scarabaeus rugosus in South Africa. An updated key to species of the genus Pavania is provided. The family Dolichocybidae is reported from the Nicaragua and Mexico for the first time.

Four new chigger species, belonging to genera Leeuwenhoekia Oudemans, 1911 (Leeuwenhoekiidae), Colicus Brennan 1970, and Herpetacarus (Vercammen-Grandjean 1960) (Trombiculidae), are described, based on specimens deposited in the Acarological collection at Centro de Coleções Taxonômicas da UFMG, including voucher material for which sequences from multiple genes are available, sampled from Minas Gerais and Amazonas states, Brazil. Leeuwenhoekia berthalutzae sp. nov. was found in association with the rodent Calomys sp. and Oligoryzomys sp., Colicus helenagrecae sp. nov. with the rodent Cerradomys cf. subflavus, Colicus carolinae sp. nov. in cave soil, off-host, and Herpetacarus mariellae sp. nov. in leaf litter, off-host. Additionally, we report a new record for Quadraseta brasiliensis Goff & Gettinger, 1989 associated with rodents from Parque Nacional Serra do Itajaí, Santa Catarina state.

The species checklist is the basic data that reflects the species diversity in a country or region. In order to commemorate the 100th anniversary of the taxonomic study of oribatid mites in China and the 60th anniversary of the Special Committee of Acarology of the Entomological Society of China, and to explore the China's biodiversity, and scientifically answer “how many species and what species are there in China”, we compiled a checklist of Chinese oribatid mites, including a total of 1000 species and 35 subspecies in 311 genera and 158 subgenera representing 112 families. In addition, we provided a brief history of taxonomic research on oribatid mites in China in the past 100 years, Chinese name, literature citations and provincial distribution information of each species and subspecies, and a list of species nomina nuda. This work will support China's actions to implement the “Convention on Biological Diversity”, and promote biodiversity research and protection.