Adult Specimens Research Articles

Two new species and new host and distribution records of Gnathia Leach, 1814 (Crustacea, Isopoda, Gnathiidae) from Western Australia and the Great Barrier Reef, Australia.

Gnathiaantennacrassasp. nov. from seagrass beds off Rottnest Island, Western Australia is the first record of any gnathiid from the entirety of Western Australia; the male can be distinguished from congeners by the stout peduncular articles of the antenna. Gnathiataurussp. nov. is described from two adult specimens reared from praniza larvae found infecting elasmobranch fishes at Heron Island, southern Great Barrier Reef; the males can be distinguished from all congeners by the dorsally strongly elongate mandibles and smoothly rounded mediofrontal process on the anterior part of cephalosome. Gnathiaaff.maculosa Ota & Hirose, 2009 is recorded from Australia, together with further records of G.trimaculata Coetzee, Smit, Grutter & Davies, 2009 and G.grandilaris Coetzee, Smit, Grutter & Davies, 2008, all from elasmobranch fishes.

Description of Discocotyle ciray n. sp. (Monogenea: Discocotylidae) from Parahucho perryi (Brevoort) from Hokkaido, Japan, with a redescription of D. sagittata (Leuckart, 1842).

Discocotyle sagittata (Leuckart, 1842) (Monogenea: Discocotylidae) is redescribed, based on specimens collected from the type host, Salmo trutta Linnaeus, from the type locality, Freiburg, Germany, supplemented with specimens from S. trutta and rainbow trout, Oncorhynchus mykiss (Walbaum) reared in an Austrian aquarium. The diagnosis of the genus Discocotyle Diesing, 1850 is emended. Discocotyle ciray n. sp. is described, based on immature, preadult and adult specimens from the salmonid, Parahucho perryi (Brevoort) at Eniwa, Hokkaido, Japan. Adult specimens of the new species were about twice as large as those of D. sagittata from S. trutta. When the type specimens of D. ciray n. sp. were examined together with museum specimens from P. perryi at Tsurui, Hokkaido, the body and clamp sizes were positively correlated to the host size. Their measurements from a smaller P. perryi at Tsurui overlapped with those of D. sagittata, showing that these size differences were not suitable differentiating keys. Discocotyle ciray n. sp. can be separated from D. sagittata by the morphologies of the female genital system (relatively anteriorly positioned ovary, short joint vaginal duct and much more strongly winding uterus). The genetic distances of COI mtDNA sequence between D. ciray n. sp. and D. sagittata were 18.0-18.6%. These remarkable genetic divergences also supported the distinct taxonomic status of D. ciray n. sp.

Exploring the range of Culex mosquitoes in Western Argentinean Patagonia, unveiling the presence of Culex pipiens bioform pipiens in South America.

Culicids in Argentinean Patagonia are characterized by low species diversity and adaptation to extreme environmental conditions, yet few studies have been conducted in the region. To further assess the occurrence of Culicidae in Western Patagonia, and in particular the presence of Culex pipiens bioforms at the southernmost extent of their distribution, immature and adult specimens were collected aboveground across various land uses located in shrubland, steppe, and deciduous forest between 38.96 and 46.55°S. Mosquitoes were reported at 35 of the 105 inspected sites. Five species from the genus Culex were identified, all of which were present in the steppe and the forest, while only Cx. apicinus and members of the Cx. pipiens complex were collected in the shrubland. Within the latter, a total of 150 specimens were molecularly identified by PCR amplification of Ace-2 and CQ11 loci. The first-to-date occurrence of bioform pipiens in South America is reported, along with the first records of Cx. quinquefasciatus signatures in Patagonia. In addition, the distribution of Cx. acharistus and Cx. dolosus as south as Santa Cruz province is expanded, and the first record of Cx. eduardoi in Río Negro province is provided. Immature specimens of Cx. pipiens were conspicuous in human-made aquatic habitats (both containers and in the ground), while Cx. acharistus was more prominent in artificial containers and Cx. eduardoi was mainly in ground habitats, either natural or human-made. These findings provide valuable insights into the distribution and ecological roles of these mosquito species in a region of extreme environmental conditions.

Caracterización ultrasonográfica de los órganos abdominales y pélvicos del oso perezoso de dos dedos (Choloepus hoffmanni) criados en cautiverio

Adult specimens of Choloepus hoffmanni, 14 females and 5 males, bred in captivity, in apparent good health, were used to perform an ultrasound evaluation of the abdominal and pelvic organs using the ESAOTE MyLab One Vet ultrasound scanner with SC3123 convex transducer, 9-4 MHz. The results indicate that the ultrasound characteristics and dimensions of the abdominal organs of C. hoffmanni are very similar to those observed in the tamandua and other companion animals of similar size; however, it differs from other species in that the liver has less echogenicity than the kidney, the stomach is large, and the testicles are located intra-pelvically; and the fullness of the stomach and urinary bladder can affect the topographic location and visualization of other abdominal organs.

Distribution, population size and conservational status of the regionally endangered Large Banded Grasshopper (Arcyptera fusca) in Hungary (Orthoptera: Acrididae)

Summary The abandonment of grasslands is a major threat to the local biodiversity of these habitats. Secondary succession may have a negative effect on species richness, especially in mountain meadows. The Large Banded Grasshopper, Arcyptera fusca (Pallas, 1773) is a typical example throughout Europe. According to former publications and our field survey of 2021, the extant number of populations of this species in Hungary has decreased from 31 to eight in the last decades. Based on the population size estimation carried out in 2021, some of the recent populations of A. fusca in Hungary count only dozens of adult specimens, while the largest ones consist of several hundreds. Their habitats cover ca. 40 hectares in all, in the North Hungarian Mountains. According to the IUCN guidelines, A. fusca should be considered endangered (EN) in Hungary. Our results show that active conservational measures with long term monitoring are important, and necessary to preserve this species together with its biodiversity-rich mountainous habitats in Hungary.

Crephlebia gen. nov., a new mayfly genus (Ephemeroptera: Leptophlebiidae) from mid-Cretaceous Kachin amber of northern Myanmar

A new mayfly genus and species of the family Leptophlebiidae, Crephlebia zhoui gen. et sp. nov., is described and illustrated based on the examination of a male adult specimen preserved in mid-Cretaceous Kachin amber from northern Myanmar. The new mayfly exhibits close resemblance to the extant genus Dipterophlebiodes Demoulin, 1954, belonging to the subfamily Leptophlebiinae. This discovery enhances our understanding of the morphology and diversity of ancient leptophlebiids within the mid-Cretaceous Burmese forest. Fossil records of Cretaceous leptophlebiids in Siberia, Lebanon, and New Jersey indicate a palearctic distribution, contrasting with their cosmopolitan extant relatives. This discrepancy raises questions about factors influencing mayfly geography during the Cretaceous and suggests potential bias in understanding ancient insect distributions due to limited findings in the southern hemisphere.

Description of a large specimen of Paralepis elongata (Brauer, 1906) from Angola, southeastern Atlantic Ocean (Aulopiformes: Paralepididae).

The elongate barracudina, Paralepis elongata (Brauer, 1906), received limited attention in the past, with only a few individuals documented, mostly in publications focusing on the feeding habits of large predatory pelagic fishes. Furthermore, the taxonomic history of the species is complicated, with some earlier sources providing incorrect information that influenced subsequent works. As a result, the accurate distribution range of P. elongata remains uncertain. An adult male specimen of P. elongata, representing the largest known individual, is reported from off Angola, southeastern Atlantic. A detailed description is provided, and the literature records of the species are reviewed and discussed.

Parataenius simulator (Harold, 1868)(Coleoptera: Scarabaeidae: Aphodiinae): a new dung beetle introduced on Rapa Nui, Chile

Parataenius simulator (Harold, 1868) (Coleoptera: Scarabaeidae: Aphodiinae: Eupariini), a small dung beetle native to South America, is reported for the first time in Rapa Nui (Easter Island), Chile. This new insular record is based on adult specimens that were intercepted at the Mataveri International Airport, and so far, there is no evidence that self-sustaining populations exist in other places on the island. A brief diagnosis for recognition of the species, adult photographs, distribution, and natural history data extracted from the literature are provided. The possible route of entry of this aphodiine into the island is discussed.

Comparative experimental study of the biomechanical properties of retrograde tibial nailing and distal tibia plate in distal tibia fracture.

Objective: A biomechanical comparative analysis was conducted to evaluate the retrograde tibial nailing (RTN) and distal tibia plate techniques for the treatment of distal tibia fractures. Methods: Fourteen fresh adult tibia specimens were selected, consisting of seven males and seven females aged 34-55years. The specimens were randomly divided into two groups (Group A and Group B) using a numerical table method, with seven specimens in each group. Group A underwent internal fixation of distal tibial fractures using RTN, while Group B received internal fixation using a plate. The axial compression properties of the specimens were tested in the neutral positions under pressures of 100, 200, 300, 400, and 500N. Additionally, the torsional resistance of the two groups was assessed by subjecting the specimens to torques of 1.0, 2.0, 3.0, 4.0, and 5.0Nm. Results: At pressures of 400 and 500N, the axial compression displacement in Group A (1.11 ± 0.06, 1.24 ± 0.05) mm was significantly smaller than that in Group B (1.21 ± 0.08, 1.37 ± 0.11) mm (p = 0.023, 0.019). Moreover, at a pressure of 500N, the axial compression stiffness in Group A (389.24 ± 17.79) N/mm was significantly higher than that of the control group (362.37 ± 14.44) N/mm (p = 0.010). When subjected to torques of 4 and 5Nm, the torsion angle in Group A (2.97° ± 0.23°, 3.41° ± 0.17°) was significantly smaller compared to Group B (3.31° ± 0.28°, 3.76° ± 0.20°) (p = 0.035, 0.004). Furthermore, at a torque of 5Nm, the torsional stiffness in Group A (1.48 ± 0.07) Nm/° was significantly higher than that in Group B (1.36 ± 0.06) N·m/° (p = 0.003). Conclusion: The results obtained from the study demonstrate that the biomechanical performance of RTN outperforms that of the distal tibial plate, providing valuable biomechanical data to support the clinical implementation of RTN.

A new species of the Cyrtodactyluschauquangensis species group (Squamata, Gekkonidae) from Lao Cai Province, Vietnam.

We describe a new species of the genus Cyrtodactylus based on five adult specimens from Bac Ha District, Lao Cai Province, northern Vietnam. Cyrtodactyluslucisp. nov. is distinguished from the remaining Indochinese bent-toed geckos by a combination of the following morphological characteristics: medium size (SVL up to 89.5 mm); dorsal tubercles in 17-19 irregular transverse rows; ventral scales in 32-34 longitudinal rows at midbody; precloacal pores present in both sexes, 9 or 10 in males, 8 or 9 in females; 12-15 enlarged femoral scales on each thigh; femoral pores 9-12 in males, 5-10 in females; postcloacal tubercles 2-4; lamellae under toe IV 21-23; dorsal pattern consisting of 5 or 6 irregular dark bands, a thin neckband without V-shape or triangle shape in the middle, top of head with dark brown blotches; subcaudal scales transversely enlarged. Molecular phylogenetic analyses recovered the new species as the sister taxon to C.gulinqingensis from Yunnan Province, China, with strong support from all analyses and the two taxa are separated by approximately 8.87-9.22% genetic divergence based on a fragment of the mitochondrial ND2 gene. This is the first representative of Cyrtodactylus known from Lao Cai Province.

High diversity, novel genotypes, and vertical transmission of hemotropic Mycoplasma in micromammals

Hemotropic mycoplasmas (hemoplasmas) are emerging zoonotic pathogens. Micromammals have received little attention as hosts for hemoplasmas despite their ubiquitous presence, high population abundances, and close association with humans. A PCR protocol targeting a fragment of the 16 S rRNA gene and direct sequencing in blood samples of 189 adult specimens and 35 fetuses belonging to three species of Eulipotyphla (shrews) and seven species of Rodentia, captured in three ecologically diverse habitats in North-Eastern Spain (Steppe, High Mountain, Mediterranean) yielded and occurrence of 26%, including 36% of 39 shrews and 23% of 150 rodents. Sequencing revealed the presence of 14 nucleotide sequence types (ntST) among the 56 readable sequences. In general, each ntST was associated with a given host species, although in some cases, the same ntST was sequenced in different species (chiefly rodents). Most ntST were closely related to rodent and/or bat hemoplasmas, but one was identical with Mycoplasma haemocanis/haemofelis, and others can be considered novel genotypes. High sequence diversity was detected in rodents, whereas in the white-toothed shrew (Crocidura russula), 9/11 sequences from two distant areas were identical. Phylogenetic and network analyses classified our sequences in different clades including hemoplasmas of rodents, carnivores, bats, and humans. Twelve of the fetuses (34.2%) of 9/12 litters (75.0%) of shrews and rodents were hemoplasma-positive, indicating frequent vertical transmission. Our study contributes to expanding our knowledge about the distribution, diversity, and transmission of hemoplasmas.

Parasitism of ladybirds by Hesperomyces in the Canary Islands

AbstractBetween 2016 and 2022, the ladybird (Coleoptera: Coccinellidae) fauna was surveyed on seven main islands of the Canary Islands archipelago. Adult specimens were collected and screened for thalli of Laboulbeniales (Ascomycota: Laboulbeniomycetes). Altogether, 9,807 ladybird specimens belonging to 39 species were screened, of which 103, representing 10 species, were infected by Laboulbeniales of the genus Hesperomyces. Morphological and molecular examination allowed to distinguish at least seven host-specific Hesperomyces species belonging to three groups: He. virescens species complex (associated with Adalia decempunctata, Harmonia axyridis, Hyperaspis vinciguerrae, Novius cruentatus, Parexochomus nigripennis, and P. quadriplagiatus), He. coccinelloides species complex (Scymnus nubilus, Sc. subvillosus durantae, and Stethorus tenerifensis), and a species (on Nephus flavopictus) that cannot be assigned to either of the above species complexes or the currently described species in the genus. The most widespread and abundant species was Hesperomyces ex St. tenerifensis; it was recorded on all seven islands with prevalence rates ranging between 0.04 and 0.19.

First Report of the Association of the Psyllid Vector Bactericera trigonica (Hemiptera: Triozidae) with 'Candidatus Liberibacter Solanacearum' in Italy.

Psyllids, members of the family Triozidae, represent a potential threat to the cultivation of solanaceous and apiaceous crops worldwide, mainly as vectors of the phloem-restricted bacterium 'Candidatus Liberibacter solanacearum' (Lso). The Lso haplotypes C, D and E are known to affect apiaceous crops, such as carrot and celery, in several European countries. In Italy, data on the incidence and natural spread of both Lso and psyllids have not been reported so far. In this study, the presence of the vectors was investigated in a main Italian district for carrot production, the "Altopiano del Fucino" area (Central Italy). Both occasional and regular surveys were carried out on a total of five carrot fields and one potato field in 2021 and 2022. Bactericera trigonica (Hodkinson), which is known to efficiently transmit Lso to carrots, was found to be well-established in the area. High levels of population density were recorded in the summer period (more than 100 adult specimens per trap caught every two weeks) and then sharply decreased after the carrot harvest, confirming the strict association of this psyllid species with crop availability. In 2022, 27.5% of the total tested psyllid samples resulted in being positive for Lso haplotypes D and E, the latter being prevalent. This survey revealed, for the first time in Italy, the presence of B. trigonica adults associated with Lso in carrot crops. Although this study was limited to a few fields located in one area, it provided important evidence of the risks for Lso outbreaks and prompted further research to assess the spread and incidence of the disease in apiaceous cultivations in Italy.

Morphology and distribution of sensilla on head appendages in the water beetle Hygrobia hermanni (Coleoptera: Adephaga: Hygrobiidae).

Sensilla on head appendages were studied in detail for the first time in a member of the relict family Hygrobiidae (squeak beetles), closely related to Dytiscidae (diving beetles). Adult and third instar larval stage specimens of Hygrobia hermanni (Fabricius, 1775) were examined using scanning electron microscopy, focusing on antennae, palps and larval mandibles. In total, 37 sensilla subtypes are described, including 22 observed in the adult (basiconica: 3; Böhm's bristles: 2; circumvallate sensilla: 2; coeloconica: 10; ovoid placodea: 3; digitiform placodea: 2) and 16 in the larva (basiconica: 4; campaniformia: 1; chaetica: 4; coeloconica: 5; trichodea: 1; unnamed: 1). Only one subtype (of sensilla coeloconica) was shared between the adult and the larva. Autapomorphies of Hygrobiidae and Dytiscidae, and putatively shared derived characters (synapomorphies) of Hygrobiidae + Dytiscidae are discussed. Among the latter, the most remarkable is the acquisition of a special sensory field, located on the apical segment of the adult maxillary palp, subapically and postero-dorsally. This sensory field is made up of ovoid multiporous sensilla placodea otherwise present on the anterior (internal) surface of antennal segments, suggesting that in a common ancestor of Hygrobiidae and Dytiscidae, maxillary palps might have taken over enhanced capacities of longe-range molecule detection.

Another ghost of Gondwana—Progradungula barringtonensis Michalik & Smith, sp. nov., a new species of the relict spider genus Progradungula (Araneae: Gradungulidae) from a temperate rainforest in eastern Australia

AbstractOdd‐clawed spiders (Gradungulinae), which are considered to be ‘living fossils’, are a faunal element of the mesic forests of eastern Australia and the South Island of New Zealand. To date, 16 species in seven genera are known, with most being highly endemic and hard to find, explaining their scarcity in collections worldwide. Particularly noteworthy is the Australian genus Progradungula that includes only two relict species from eastern Australia (Progradungula carraiensis from the Carrai limestone caves in northern New South Wales and Progradungula otwayensis from Nothofagus rainforests in the Otway Range, southern Victoria) and are known from only a handful of adult specimens. Both species are large nocturnal predators with a rather cryptic lifestyle, which construct unique ladder‐like catching webs composed of non‐combed and combed cribellate silk with exceptional properties. Here, we describe a new relict species, Progradungula barringtonensis Michalik & Smith, sp. nov., from isolated Nothofagus forest patches in Barrington Tops National Park (NSW, Australia). The male of this species is significantly larger than those of P. carraiensis and P. otwayensis and exhibits characteristics of the male genitalia of both species. The webs are similar to those of the other Progradungula species. Field observations revealed that the catching ladder had few looping segments, similar to P. otwayensis, but an immature in captivity constructed webs with more looping segments, similar to P. carraiensis, supporting the previously proposed hypothesis that food availability may explain the plasticity of the catching ladder structure.

Record of <i>Downsiomyia albolateralis</i> (Theobald) (Diptera: Culicidae) from the Himalayan Plains of West Bengal

The present study was carried out with the aim to characterize a mosquito species that was documented near about a century ago from Darjeeling district of northern West Bengal, India. Mosquito larvae were collected from the bamboo stumps or holes of sub-Himalayan plains of Darjeeling district, West Bengal, India. Collected immatures were reared upto adults maintaining standard protocol. Larva and adult specimens were investigated for morphological identifications upto generic and species level. In the present study, the Niveus species Downsiomyia albolateralis (Theobald, 1908) is a newer addition to the mosquito fauna in the region and it will update the mosquito checklist for the knowledge of vector and non-vector species.

Diversity, Distribution and Host Blood Meal Analysis of Adult Black Flies (Diptera: Simuliidae) from Thailand.

Understanding the factors associated with the species diversity and distribution of insect vectors is critically important for disease epidemiology. Black flies (Diptera: Simuliidae) are significant hematophagous insects, as many species are pests and vectors that transmit pathogens to humans and other animals. Ecological factors associated with black fly species distribution have been extensively examined for the immature stages but are far less well explored for the adult stage. In this study, we collected a total of 7706 adult black fly specimens from various locations in forests, villages and animal shelters in Thailand. The integration of morphology and DNA barcoding revealed 16 black fly taxa, including Simulium yvonneae, a species first found in Vietnam, which is a new record for Thailand. The most abundant species was the Simulium asakoae complex (n = 5739, 74%), followed by S. chumpornense Takaoka and Kuvangkadilok (n = 1232, 16%). The Simulium asakoae complex was dominant in forest (3786 of 4456; 85%) and village (1774 of 2077; 85%) habitats, while S. chumpornense predominated (857 of 1175; 73%) in animal shelter areas. The Simulium asakoae complex and S. nigrogilvum Summers, which are significant pests and vectors in Thailand, occurred at a wide range of elevations, although the latter species was found mainly in high (>1000 m) mountain areas. Simulium chumpornense, S. nodosum Puri and the S. siamense Takaoka and Suzuki complex occurred predominately in low (<800 m)-elevation areas. Simulium furvum Takaoka and Srisuka; S. phurueaense Tangkawanit, Wongpakam and Pramual; and S. nr. phurueaense were only found in high (>1000 m) mountain areas. A host blood meal analysis revealed that the S. asakoae; S. chamlongi Takaoka and Suzuki; S. nigrogilvum; S. chumpornense; and the S. striatum species group were biting humans. This is the first report of the latter two species biting humans. We also found that S. chumpornense was biting turkeys, and S. chamlongi was biting chickens, which are new host blood sources recorded for these species. In addition, we found that the S. feuerborni Edwards complex was biting water buffalo, which is the first report on the biting habits of this species.

Gafftopsail Catfish in Texas estuaries: Population trends and ecosystem implications

AbstractObjectiveGiven the limited information on population dynamics of Gafftopsail Catfish Bagre marinus in the western Gulf of Mexico, the objectives of this study were to determine the status of this species in Texas estuaries by assessing trends in relative abundance, length, and habitat preferences from fishery‐independent trawl (juvenile) and gill‐net (adult) data, as well as angler harvest trends from fishery‐dependent creel surveys collected in all Texas estuaries.MethodsFishery‐independent and ‐dependent monitoring data were collected by the Texas Parks and Wildlife Department in all major bay systems of the Texas coast from 1983 to 2022. Linear trend analysis was used to assess trends across the full time series and all major bay systems for both juvenile and adult specimens and for total recreational harvest. Boosted regression tree analysis was used to assess habitat preference for both juveniles and adults.ResultBoth juvenile and adult catch rates consistently increased in most Texas estuaries, with the most extreme increases occurring in central Texas coast estuaries beginning in the early 2000s. During the same time frame, mean lengths of adult specimens significantly decreased in many of the same estuaries. Habitat suitability analysis suggested that Gafftopsail Catfish were primarily influenced by salinity, though they still exist across a very broad range of salinity conditions. Angler catch rates showed some localized patterns of increasing or decreasing trends, though they generally did not follow fishery‐independent trends for most estuaries.ConclusionThese trends interpreted in the context of the known trophic role of Gafftopsail Catfish imply the potential for larger ecosystem‐level effects on both prey organisms and competitors. A more thorough awareness of these trends and potential interactions should help fisheries managers operate in an ecosystem‐based context when investigating population dynamics and recommending management strategies.

New deep-sea species of Aborjinia (Nematoda, Leptosomatidae) from the North-Western Pacific: an integrative taxonomy and phylogeny.

Marimermithid nematodes parasitising invertebrates are mainly found in the deep-sea environments. Several adult and juvenile specimens marimermithids of the genus Aborjinia have been found in bottom sediments and inside Polychaeta during recent cruises to the Kuril-Kamchatka trench and the Kuril Basin (the Sea of Okhotsk). New species are described based on integrative study. Aborjiniaprofundasp. nov. differs from A.eulagiscae by the location of the ventral gland cell bodies (posterior to the nerve ring vs posterior to the cardia), by the smaller body size (23-28 mm vs 103-132 mm) and shorter tail (193-263 µm vs 500-850 µm). BI and ML phylogenetic analyses based on 18S and 28S rDNA suggest that genus Aborjinia belongs to the family Leptosomatidae. Based on molecular and morphological characters the new genus Paraborjiniagen. nov. is proposed for A.corallicola. Within the family Leptosomatidae the new genus differs from all genera except Aborjinia by its endoparasitic lifestyle and hologonic ovaries. Paraborjiniagen. nov. differs from Aborjinia by the position of cephalic sensitive organs (outer labial and cephalic papillae in two separate circles vs outer labial and cephalic papillae in one circle) and by the parasitic adult (vs free-living in Aborjinia).

Morphological symmetry of Rhipidomys mastacalis (Mammalia, Rodentia, Cricetidae) in fragmented habitats of the Atlantic Forest in Northeastern Brazil: a study on the influence of the environment on an endemic species

Abstract The Brazilian Atlantic Forest has undergone significant transformation, resulting in habitat loss and the endangerment of many species of mammals and other vertebrates. In this study, the presence of fluctuating asymmetry of four anatomical structures of the arboreal rodent Rhipidomys mastacalis was evaluated using geometric morphometrics. The study focused on adult specimens collected in a mosaic of vegetation composed of forested vegetation, occupancy mosaics in forested areas, and cocoa plantations. The results showed significant values of fluctuating asymmetries in all structures and in all areas. The skulls and scapulae showed the highest values of asymmetry in forested vegetation and cocoa plantations, while the mandibles showed the greatest values in forested vegetation, and the pelvis in occupancy mosaics and cocoa plantations. These findings are consistent with previous studies that have evaluated developmental stability in mammals and suggest that high asymmetry values indicate an effect on different phases of ontogeny, which can harm the survival of a species in future generations. Overall, this study provides important insights into the impacts of habitat fragmentation on Rhipidomys mastacalis and highlights the need for conservation efforts to preserve the integrity of the Brazilian Atlantic Forest and its diverse range of wildlife.