Vol 104, No 12 (2025)

A list of 22 oribatid mite (Oribatida) species belonging to 20 genera and 11 families, all recorded from Guadeloupe, Caribbean, Neotropical Region, is presented. One new species of Dynatozetes (Mochlozetidae) – D. mishevi Ermilov et Georgiev sp. n. – is described, based on adult and tritonymphal instars collected from the detritus and dry leaves of Mangifera indica and Musa sp. The adult is characterized by the presence of a rounded rostrum, a very long interlamellar seta, and a simple lamellar cusp (a lamellar tooth absent). Our description of the tritonymphal instar is the first concerning the juveniles of Dynatozetes. The tritonymph is characterized by the presence of long and subflagellate gastronotic setae c₁, c₃, da, la, dm, lm, dp, lp, h₁–h₃, p₁, p₂, a short and acicular gastronotic seta c₂, a vestigial gastronotic seta p₃, and a narrowly lanceolate bothridial seta. Identification keys to the known larvae and tritonymphs of Mochlozetidae are provided.

Allopsontus artaevi sp. n. is described as the only species in the genus, in which the compound eyes of males and females are not in touch. The new species belongs to the subgenus Allopsontus s. str., which presently includes 23 species. In males and females of this subgenus, the coxites of abdominal segments II–V have two pairs of eversible vesicles, and the ovipositor of females is long, slender, and segmented, without digging spines. Among them, in males of A. artaevi sp. n. and seven other described species of this subgenus, the surface of segments 2 to 7 of the maxillary palps and segments 2 and 3 of the labial palps have numerous, pigmented, small, appressed setae. The new species differs from them in eye color, the structure of the sensory field on the male fore femora, and other characteristics. A. artaevi sp. n. seems to be especially similar to both A. tauricus Kaplin, 2024 and A. stepposus Kaplin, 2024 from Crimea in pigment distribution, eye color, and daily activity, but differs in the structure of the visual organs and the maxillary and labial palps.

Amphibians are known to be capable of using both proximal and distant visual landmarks for orientation during the summer period, but their relative importance for amphibians remains almost unstudied. The present research tests the significance of distant landmarks in the case of the Common toad, Bufo bufo. Rectangular mazes consisting of one central and 4 side rooms were used for experiments. Various objects that could be used as orientational cues (proximal landmarks) were placed on the floor of the central room, while distant landmarks were positioned on screens outside the maze (a cardboard figure 155 × 30 cm in size). The experiment consisted of two consecutive trials, each lasting 4 h. During the first trial, the animal learnt the location of one of the four rooms of the rectangular maze (160 × 96 cm) that contained attractive “resources” (container with moving prey, water source and shelter). The first trial of the experiment was followed by a 30 min break. During the break, the “resources” were removed from the maze and all four side rooms were left empty, but the location of the distant landmark was changed 180° relative to the maze (proximal landmarks were left in the same place). According to our hypothesis, if the animal uses a distant landmark to learn the location of the target room, in the second trial it will spend more time and travel a greater distance in the room located diagonally to the “resource” room. However, if the distant landmark is not the primary one used to find the target room, the amphibian would visit the room that earlier contained the “resources” more often like in the first trial. A total of 20 adult common toads were tested individually. In this experimental situation, the toads successfully found the room, where the “resources” were previously located, 30 min following the first trial. Thus, our distant visual landmark was not used by common toads as a primary one to learn the location of the target room, but changing the location of this landmark resulted in increased locomotor activities in the second trial.

Sokolov’s dwarf hamster (Cricetulus sokolovi) is one of the least studied species in the genus Cricetulus, inhabiting the areas with arid, sharply continental climates of Mongolia and northern China. The first successful laboratory breeding of this species has been documented. A breeding colony was established from two wild-caught pairs, obtaining 12 first-generation and 28 second-generation offspring. Under simulated natural photoperiod and temperature conditions, the seasonal dynamics of body mass, body temperature, and the circulating concentrations of sex steroids and cortisol in both sexes were investigated. Torpor was recorded for the first time in this species, occurring exclusively in winter and only in females with a low body mass. Both sexes showed a decrease in body mass in autumn, accompanied by a reduction in testosterone in males. In contrast, cortisol levels increased significantly with the onset of cold in both sexes. A generalized linear mixed-effects model identified body mass and minimum ambient temperature as key predictors of torpor frequency in females during autumn and winter, whereas the cortisol level was not a significant factor. This demonstrates sexual dimorphism in energy-saving strategies in C. sokolovi and confirms a significant role of body mass in torpor regulation in this species.