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The systematic position of Quentinia mesovitellinica (Rêgo, 1967) (Cestoda, Cyclophyllidea) from the hystricomorph rodent Galea spixii (Wagler) (Caviidae) in Brazil is reevaluated based on published information. Quentinia mesovitellinica is generally thought to belong to the family Catenotaeniidae, being thus the only catenotaeniid cestode parasitizing hystricomorph rodents and also the only catenotaeniid in South America. However, the present study shows that Q. mesovitellinica differs fundamentally from Catenotaenia Janicki, 1904 sensu lato and other catenotaeniids with respect to several morphologic features, but shares these features with Monoecocestus Beddard, 1914 sensu Beveridge (1994), a genus in the family Anoplocephalidae sensu stricto (i.e. sensu Spasskii, 1951). However, Q. mesovitellinica is not assigned here to Monoecocestus, because the latter is a morphologically heterogeneous genus and will probably be split when subjected to a comprehensive phylogenetic and taxonomic analysis. Instead, Quentinia Spasskii, 1969 is considered a valid genus in the family Anoplocephalidae s. s. The morphologically closely related Monoecocestus eljefe Haverkost & Gardner, 2010 from Galea musteloides Meyen in Bolivia is assigned to Quentinia as Q. eljefe (Haverkost & Gardner, 2010) n. comb. An amended diagnosis is provided for Quentinia.

Here I reviewed the Pleistocene caviomorphs collected by Santiago Roth (collection from Catalog No. 5) and housed at the paleontological collection of the Paläontologisches Institut und Museum, Universität Zürich, Zurich (Switzerland). The fossils were found in Pleistocene strata from Buenos Aires and Santa Fé provinces (Argentina) during the late nineteenth century. The material includes craniomandibular remains assigned to Lagostomus maximus (Chinchilloidea: Chinchillidae), craniomandibular and postcranial (thoracic and sacral vertebra, left scapula, left femur, and right tibia) bones identified as Dolichotis sp. (Cavioidea: Caviidae), and a fragmented hemimandible and isolated tooth of Myocastor sp. (Octodontoidea: Echimyidae). Other rodent specimens from this collection (Ctenomys sp. and Cavia sp.) are possibly sub-recent materials. [ABSTRACT FROM AUTHOR]

Abstract Here I reviewed the Pleistocene caviomorphs collected by Santiago Roth (collection from Catalog No. 5) and housed at the paleontological collection of the Paläontologisches Institut und Museum, Universität Zürich, Zurich (Switzerland). The fossils were found in Pleistocene strata from Buenos Aires and Santa Fé provinces (Argentina) during the late nineteenth century. The material includes craniomandibular remains assigned to Lagostomus maximus (Chinchilloidea: Chinchillidae), craniomandibular and postcranial (thoracic and sacral vertebra, left scapula, left femur, and right tibia) bones identified as Dolichotis sp. (Cavioidea: Caviidae), and a fragmented hemimandible and isolated tooth of Myocastor sp. (Octodontoidea: Echimyidae). Other rodent specimens from this collection (Ctenomys sp. and Cavia sp.) are possibly sub-recent materials.

The mountain cavy Galea musteloides Meyen, 1833 is a terrestrial caviomorph rodent with diurnal and colonial habits. It occupies grassland areas and rocky shrub steppes in the arid highlands of the central Andes of western Bolivia, northern Chile, and southeastern Peru. Recent phylogenetic studies based on the analysis of mitochondrial DNA showed that this species has a genealogy geographically structured into two main clades, one encompassing those populations usually referred to G. m. auceps (Thomas 1911) and G. m. musteloides, and another referable to G. m. boliviensis (Waterhouse 1848). Multivariate statistical analysis of 16 craniodental measurements corresponding to seven geographical groups supports this conclusion, allowing us to recognize two subspecies within musteloides, for which the names of musteloides (including auceps) and boliviensis (including G. monasteriensis Solmsdorff, Kock, Hohoff, & Sachser, 2004) are available. Due to some uncertainties in the original reference, we also restricted the type locality of G. musteloides to Pisacoma, Puno, Peru. [ABSTRACT FROM AUTHOR]

The Subfamily Dolichotinae comprises two living species, Dolichotis patagonum, an emblematic component of the Patagonian fauna of Argentina, and Dolichotis salinicola, endemic to the Chaco ecoregion. These two species are also considered as pertaining to different genera, D. patagonum and Pediolagus salinicola. The oldest records of Dolichotis come from the Pliocene–Pleistocene boundary of northeastern and central Argentina, and the late Pleistocene from southern Brazil, and northern and southern Uruguay. Five fossil species were described from the Pleistocene and Holocene in central Argentina (D. minor, D. plathycephala, D. major, D. intermedia, and D. improla). "Orthomyctera" chapalmalense was described on the basis of remains from the coast of Mar del Plata and Chapadmalal, Buenos Aires Province, Chapadmalal Formation (late Pliocene, 3.74–3.04 Ma). A new detailed description of the holotype and its comparison with closely related taxa suggests that this species is more related to the genus Dolichotis, resulting in the new combination D. chapalmalense. The close affinities with Dolichotis revealed by phylogenetic analyses combined with molecular and morphological characters were corroborated in previous analyses. The origin of this lineage extends at least to a million years ago, taking the record back to the middle Pliocene. The evolutionary novelties that appear at least since the Pliocene, marking a key period for the Caviidae, are analyzed. Based on a phylogenetic perspective with the inclusion of the fossil record, our data support the inclusion of the two species (D. patagonum and D. salinicola) in a single genus. [ABSTRACT FROM AUTHOR]

A new hydrochoerine rodent, Cardiatherium calingastaense sp. nov. (Caviidae), is described based on the specimen INGEO-PV 87. It was recovered from the late Miocene Las Flores Formation, cropping out at the Puchuzum locality, San Juan Province, Argentina. The new species is based on a particular combination of characters, among which the following can be highlighted: p4 with internal fissures equally deep as in Cardiatherium paranense, secondary external fissure as in Cardiatherium patagonicum, and lacking the fifth internal fissure and supernumerary internal fissure, as in C. paranense; m3 with a conspicuous labial column in the posterior ramus of the second prism; very deep primary and secondary external fissures in upper cheek teeth, the former producing a labial strong step-shaped profile in M2; sagittal crest on the parietals; bullae small in ventral view; scars of the origin of the masseter medialis muscle with an anterior projection up to the level of the incisive foramen and the maxilla-premaxilla suture. The phylogenetic analysis supports the taxonomic proposal of creating a new species of Cardiatherium and shows C. calingastaense sp. nov. as the sister group of the other species of the genus. The lineage leading to the clade Cardiatherium + largest capybaras would have originated at least during the Chasicoan SALMA (early late Miocene). Cardiatherium calingastaense sp. nov. adds to the previous record of Cardiatherium chasicoense and Cardiatherium paranense in the late Miocene of San Juan and Mendoza provinces, respectively, thus increasing the diversity of capybaras in central-west Argentina.

Being able to study anatomical structures of wildlife species for science and clinical practice is of great importance. We aimed to describe the normal gross osteology of the common adult capybara Hydrochoerus hydrochaeris (Linnaeus, 1766), using macerated bone specimens and high-resolution digital radiography. The complete axial and appendicular skeleton was further compared with previously reported anatomical findings. For this purpose, we used three adult capybara cadavers (two females and one male), with a mean bodyweight of ±50 kg. Some H. hydrochaeris-specific morphological characteristics, especially in the skull region, show evidence of adaptation to aquatic life, such as an elongated head shape, with eyes, ears, and nose, located dorsally, to stay above water. Additionally, the entire bone structure demonstrates the size and weight support of the largest rodent and its adaptation with respect to foraging and locomotion behaviors. As a semi-aquatic herbivore, classified as cursorial (having limbs adapted for running), the authors believe it should be reclassified as cursorial-swimming/diving. Moreover, we argue to consider a differentiation between H. hydrochaeris silvestris to H. hydrochaeris synanthrope, due to substantial weight variation, in some cases > 100%. This inevitably has an impact on the development of bone structure, thus influencing habitual adaptation, and consequently, its clinical implications and animal handling. Radiography exams helped in the identification of bone structures, which otherwise were not observed in anatomical specimens, such as ossa sesamoidea, including the ossicle lunulae. Likewise, the radiographs were particularly helpful in overall better comprehension of the intubation and catheterization procedures. We believe this work can contribute as a reference to anatomical studies for students and professionals acting in clinic, surgery, and research.

Copyright of Veterinarski Glasnik is the property of Veterinarski Glasnik and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The dynamics of species diversification have attracted significant scientific attention in recent decades. Many lineages tend to maintain their niche characteristics over evolutionary time, a phenomenon known as phylogenetic niche conservatism (NC), which can slow the processes of ecological speciation by diversification selection. NC can, however, promote speciation through neutral evolution, favoring the geographic isolation of populations. Among the mega-diverse Rodentia group, the low species richness of the family Caviidae stands out. Here, we analyzed if the processes of climatic NC are related to the slow diversification observed in the Caviidae family. Locality data for 13 species and nine climatic variables were used to generate ecological niche models. Niche similarity was quantified using the Schoener D index and used to examine correlations between the times of species divergence and niche similarities, thus characterizing their niche occupation profiles (NOP). The NOP were subsequently used to perform phylogenetic niche reconstructions for these species. Niche models accurately described known distributions of species. The greatest niche overlap documented was between Kerodon rupestris and Galea spixii (0.86). The niche and species divergence times showed a negative correlation (beta = -0.013; p = 0.01). These results support the existence of NC, with phylogenetically closer species occupying similar niches, and emphasize the importance of NC in diversification processes at continental scales in a slowly diversifying group. [ABSTRACT FROM AUTHOR]

Caviidae is one of the groups of rodents with the greatest ecomorphological disparity, and with currently three known lineages: Caviinae (cuises), Dolichotinae (maras), and Hydrochoerinae (capybaras). Caviinae include small caviids represented by three extant genera (Microcavia, Cavia, and Galea) and three fossils forms (Dolicavia, Palaeocavia, and Neocavia). In Argentina, the fossil record of Caviinae is continuous and abundant since the late Miocene. Neocavia, specifically, is represented by different species recorded in the late Miocene–Pliocene. Here, we describe a new species of Neocavia from the late Miocene–early Pliocene of the Cerro Azul Formation (La Pampa Province, Argentina), and provide a re-description of already known species (Neocavia lozanoi and “Neocavia depressidens”). Also, we perform a more comprehensive review of the genus and include the Neocavia species in a phylogenetic context within Caviinae. We analyze the main patterns of the evolution of the tympanic bullae within Caviidae, and infer about a possible occasional fossorial habit of Neocavia. The morphological and phylogenetic analyses indicate that Neocavia is more closely related to Dolicavia and Microcavia than to the other Caviinae, and confirm the monophyly of the genus, with at least two clearly differentiable species. Since this study cannot confirm the systematic position and validity of “N. depressidens”, we suggest not to use this taxon as a biostratigraphic indicator.

Quantification of morphological diversity among herbivorous mammals and comparisons between herbivorous marsupials and placentals are scarce. In this report we compared morphological variation of the skull and mandible in three representatives of caviid rodents and three species of macropodid marsupials, whose size is comparable, using three-dimensional geometric morphometrics. We applied two levels of comparison, one pointed to a placental-marsupial dichotomy and another pointed to the intra-variation in each group. We also performed an analysis of modularity based on a likelihood approach in order to evaluate different modularity models and analyzing the intra- and inter-module correlation (i.e., morphological integration). Beyond strong morphological differences that split caviids and macropodids along the first axes of the morphospaces of the cranium and mandible, they shared similar allometric shape changes, including the enlargement of muscular attachment areas and lengthening of the diastema. In both clades, the largest value of inter-module correlation (as a measure of modular integration) was found for the oral-nasal and orbit modules. We reported relatively low values of within-module correlation for the oral-nasal and molar modules in macropodids while the opposite was recorded for caviids. Beyond the great differences in cranial structure, one of the factors that influence the patterns of morphological variation and differential integration was the processing of plant matter which seems to induce strong structural changes in both clades, in which the efficiency of the masticatory apparatus is resolved in a similar way. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the healing of critical-size cranial bone defects (9-mm-diameter) in guinea pigs treated with a bovine bone-derived resorbable membrane. Materials and Methods: A sample of 42 guinea pigs was divided into test (n = 20), control (n = 20), and standard (n = 2) groups. A full-thickness trephine defect was made in the fronto-parietal bone of each animal. In the test group, the internal and external openings of the defect were each closed with a separate membrane, and the space between them was filled with blood clot and a central spacer. In the control group, the defect was filled only with the blood clot and spacer. At 1, 3, 6, and 9 months later, the calvarias (5 per period) for both the test and control groups were collected, fixed, radiographed, and histologically processed. The standard- group animals were sacrificed immediately after surgery and used to determine the initial size of defect radiographically. The areas of defects in the radiographs were measured with image-analysis software and were compared between groups and periods by multiple regression analysis with the Bonferroni correction. Results: At 1 and 3 months, newly formed woven bone was histologically observed in both test and control groups. Radiographically, this new bone occupied an average of 32% of the defect area at 1 month and 60% at 3 months in the test group. In the control group, 21% of the defect was filled at 1 month and 39% at 3 months. However, the differences between treatments were not statistically significant (P > .05). At 6 and 9 months, a significant increase in newly formed lamellar bone was seen histologically in both groups. Radiographically, for the test group, the new bone occupied an average of 82% of the defect area at 6 months and 96% at 9 months. For the control group, new bone composed an average of 45% of the defect area at 6 months and 40% at 9 months. The differences between the test and control groups were statistically significant at 6 and 9 months (P < .05). Complete or almost complete filling of the defect was observed in several cases. Conclusion: It was concluded that the bovine bone-derived membrane is highly biocompatible and is able to promote good healing of critical-size defects in calvaria of guinea pig. [ABSTRACT FROM AUTHOR]

The guinea pig (Cavia porcellus) or cavy is a grass-eating rodent. Its main diet consists of grass or hay, which comprises cellulose, hemicellulose, lignin and their derivatives. Here, the microbial diversity of faecal samples of two guinea pigs and microbial enrichments made with substrates, including starch waste and dried grass, were investigated along with organic acid production profiles. The microbial communities of the faecal samples were dominated by the phyla Bacteroidetes (40%) and Firmicutes (36%). Bacteroidales S24-7 (11% in Cavy 1 and 21% in Cavy 2) was the most abundant order. At genus level, many microorganisms remained unclassified. Different carbon sources were used for organic acid production in faecal enrichments. The dominant bacterial groups in the secondary enrichments with dried grass, starch waste and xylose were closely related to Prevotella and Blautia. Acetate was the predominant organic acid from all enrichments. The organic acid production profiles corresponded to a mixed acid fermentation but differed depending on the substrate. Eight phylogenetically different isolates were obtained, including a novel Streptococcus species, strain Cavy grass 6. This strain had a low abundance (1%) in one of the faecal samples but was enriched in the dried grass enrichment (3%). Cavy grass 6, a fast-growing heterolactic bacterium, ferments cellobiose to lactate, acetate, formate and ethanol. Our results show that cavy faecal samples can be applied as microbial source for organic acid production from complex organic substrates. The cavy gut contains many as-yet-uncultivated bacteria which may be appropriate targets for future studies. [ABSTRACT FROM AUTHOR]

A new hydrochoerine rodent, Cardiatherium calingastaense sp. nov. (Caviidae), is described based on the specimen INGEO-PV 87. It was recovered from the late Miocene Las Flores Formation, cropping out at the Puchuzum locality, San Juan Province, Argentina. The new species is based on a particular combination of characters, among which the following can be highlighted: p4 with internal fissures equally deep as in Cardiatherium paranense, secondary external fissure as in Cardiatherium patagonicum, and lacking the fifth internal fissure and supernumerary internal fissure, as in C. paranense; m3 with a conspicuous labial column in the posterior ramus of the second prism; very deep primary and secondary external fissures in upper cheek teeth, the former producing a labial strong step-shaped profile in M2; sagittal crest on the parietals; bullae small in ventral view; scars of the origin of the masseter medialis muscle with an anterior projection up to the level of the incisive foramen and the maxilla-premaxilla suture. The phylogenetic analysis supports the taxonomic proposal of creating a new species of Cardiatherium and shows C. calingastaense sp. nov. as the sister group of the other species of the genus. The lineage leading to the clade Cardiatherium + largest capybaras would have originated at least during the Chasicoan SALMA (early late Miocene). Cardiatherium calingastaense sp. nov. adds to the previous record of Cardiatherium chasicoense and Cardiatherium paranense in the late Miocene of San Juan and Mendoza provinces, respectively, thus increasing the diversity of capybaras in central-west Argentina. [ABSTRACT FROM AUTHOR]

Abstract During the last decade, the taxonomic, phylogenetic, and evolutionary knowledge of the groups within Caviidae (i.e. Hydrochoerinae, Caviinae, and the stem eocardiids) has been improved and expanded. However, the evolutionary patterns of Dolichotinae are poorly known due to the lack of detailed taxonomic studies of their fossil forms. The subfamily Dolichotinae are known as patagonian mara (Dolichotis patagonum) and chacoan mara or "conejo de los palos" (Dolichotis [ Pediolagus ] salinicola) and, within Caviidae, are the second largest rodents after the capybaras. The subfamily presents its highest diversity in the late Miocene. Prodolichotis is represented by six species, but most of them have not been studied since their original description. An exhaustive description of the type species of Prodolichotis from the late Miocene-Pliocene of Northwest Argentina is here reported with the objective of filling the gaps and increasing the knowledge about the origin and diversification of the Dolichotinae. The phylogenetic analysis implemented here indicates that Prodolichotis prisca is one of the most basal species within Dolichotinae, suggesting that this group originated at least during the Miocene. [ABSTRACT FROM AUTHOR]

Summary Disorders of the female genital tract are among the most common disorders in pet guinea pigs (Cavia porcellus); however, knowledge of many aspects of these disorders is sparse, especially regarding their incidence and age distribution. Ovarian cysts, as the most common genital tract disorder in guinea pigs, have been investigated in detail; however, information on the nature of these cysts is inconsistent. The present study reviewed genital tract disorders occurring within 655 full post-mortem examinations of intact female pet guinea pigs and 64 female genital tract biopsies examined over a 22.5 year period. Age distribution was determined from 550 post-mortem examinations of animals of known age. Genital tract disorders were found in 295 post-mortem examinations (45.0%) in animals with a median age of 52 months. Additionally, disorders were found in all genital tract biopsy samples from guinea pigs with a median age of 48 months. The incidence of genital tract diseases increased from 1.5% in guinea pigs ≤6 months of age to up to 77.8% in animals >6 years of age. Ovarian cysts were the most common genital tract disorder, found in 245 of the 655 post-mortem cases (37.4%) and 38 of 43 ovarian biopsy samples (88.4%). The incidence of ovarian cysts increased with advancing age, reaching 75.6% in animals >6 years. In 119 cases, histopathology and immunohistochemistry confirmed cystic rete ovarii as the only cyst type. A Fallopian tube adenoma was found in a single case, so disorders of the Fallopian tube should be considered rare. Uterine disorders were diagnosed in 17.4% of the post-mortem examinations and 98.1% of uterine biopsy samples. Uterine neoplasia, hyperplasia and inflammation were common, but occurred at different ages. The incidence of uterine neoplasia and hyperplasia was higher in older animals (>15% in guinea pigs >6 years), while the incidence of uterine inflammation was the highest (17.9%) in animals aged 7–12 months. An association between ovarian cysts and uterine neoplasia or hyperplasia was not evident. Vaginal disorders were rare and included leiomyoma, polyps and vaginitis. [ABSTRACT FROM AUTHOR]

Resumo: O preá é um roedor típico da caatinga pertencente à família Caviidae. Considerando a inexistência de dados sobre o arco aórtico do preá, foi realizado este estudo tendo como objetivo descrever os ramos colaterais do arco aórtico neste cavídeo, e dessa forma, contribuir com dados para biologia da espécie. Foram utilizados vinte preás machos provenientes de estudos anteriores e encontravam-se armazenados em freezer no Centro de Multiplicação de Animais Silvestres (CEMAS/UFERSA). Os animais foram descongelados, a cavidade torácica foi aberta, a aorta canulada e o sistema vascular lavado com solução salina e em seguida, injetado látex Neoprene corado com pigmento vermelho, amarelo ou branco. Posteriormente, os animais foram fixados em formol e depois de 72 horas, dissecados e analisados, sendo obtidos desenhos esquemáticos e os exemplares mais representativos fotografados. O arco aórtico do preá emitiu como ramos colaterais, o tronco braquiocefálico e a artéria subclávia esquerda. O tronco braquiocefálico originou na maioria das peças estudadas, a artéria carótida comum esquerda e o tronco braquiocarotídeo, do qual surgem as artérias subclávia direita e carótida comum direita. As artérias subclávias direita e esquerda em todos os animais estudados emitiram a artéria vertebral, a artéria torácica interna, a artéria cervical superficial, o tronco costocervical e a artéria axilar. O padrão da formação do arco aórtico do preá assemelhou-se ao observado em outros roedores, tais como no mocó, no porquinho-da-índia e na chinchila.

Extinct Hydrochoerinae traditionally included within ‘Cardiomyinae’ (Cavioidea, Caviidae) are caviomorph rodents well represented in the late Miocene to late Pliocene of Argentina, but their paleobiology has received little scientific attention. The postcranium of these rodents is poorly known and has not been considered in morphofunctional or systematic studies. Here, we provide the first description of the postcranium of the basal hydrochoerine Cardiomys Ameghino, 1885, based on a well-preserved specimen from the late Miocene of Central Argentina, and evaluate its paleobiological and systematic implications. A morphofunctional study and a character mapping analysis were performed. We concluded that most of its postcranial features are neither adaptations to a specialized cursoriality, as in some extant cavioids, nor major modifications associated with swimming, as in extant capybaras. Cardiomys exhibits several features (high humeral distal articular surface, perforated olecranon fossa, proximal portion of radius cranially located with respect to the ulna, subrectangular-shaped radial head with flattened ulnar facet, calcaneocuboid joint distally located with respect to the astragalonavicular joint) that allow us to interpret it as an ambulatory caviid. Among cavioids, some features of Cardiomys are more similar to those of Hydrochoerus Brisson, 1762 (lateral coronoid process reduced, humeral capitular tail well differentiated, capitular tail facet of the radial head well developed and relatively short craniodistally, plantar process of the navicular massive and short). Other postcranial features (relatively longer and more gracile third metatarsal and phalanges, straight caudal border of the ulna) suggest that Cardiomys would have been a generalized hydrochoerine, as also indicated by its dental and cranial characters. [ABSTRACT FROM AUTHOR]

Finding the optimal timing for breeding is crucial for small mammals to ensure survival and maximize lifetime reproductive success. Species living in temperate regions therefore often restrict breeding to seasons with favorable food and weather conditions. Although caviomorph rodents such as guinea pigs are described as non-seasonal breeders, a series of recent publications has shown seasonal adaptations in litter size, offspring birth mass and maternal investment. Here, we aim to test if seasonal patterns of litter size variation found in earlier studies, are mediated by seasonal differences in female estrus length, fertilization rate and mating behavior. The female estrus period was longer in fall compared to all other seasons (p < 0.001), frequently lasting 7–9 days while estrus in spring usually lasted less than 2 days. In fall, females mated later during estrus (p < 0.001), resulting in reduced fertilization rates (p < 0.001). Fertilization rate was well above 95% in summer while it dropped to less than 85% in fall and winter. While none of the male mating characteristics such as number and duration of copulations differed across seasons, the number of mating bouts was reduced in fall (p = 0.04). Finally, the developmental stages of flushed embryos were more diverse in spring and summer compared to fall and winter. These results suggest that seasonal differences in fertilization rate and quality of implanted embryos are mediated by female estrus length and timing and intensity of mating behavior. Together, these effects contribute to the observed differences in litter size across seasons. [ABSTRACT FROM AUTHOR]

Spix's Yellow-toothed Cavy is a histrichomorphic rodent of the Caviidae family found in South American countries such as Brazil and Bolivia. It is a widely-used species as an experimental model in research in reproductive biology due to morphological and reproductive characteristics, such as the similarity in the placental development of Galea spixii and human species. However, there are no studies on the behavior of this species or on its brain morphology. Considering the lack of information in the literature about the brain and internal structures of Galea spixii, this study aimed to stereologic evaluate the brain as well as the volumetric proportions of the hippocampus and corpus callosum. Therefore, ten healthy animals were used from the Wild Animal Multiplication Center of the Universidade Federal Rural do Semiárido. The brains were measured in terms of external length, height and width, followed by fixation in paraformaldehyde solution 4% and coronary cuts with a thickness of 4mm and the rostral face of each cut was photographed, with the images being analyzed to determine the volumetric proportions of the required areas. There was no statistically significant difference between the means of volume, length, width and height when the right and left hemispheres were compared, and there was also no statistically significant difference between the volume of the corpus callosum and hippocampus in both hemispheres. The brain of Galea spixii is larger when compared to the rodent Rattus norvegicus. Volumetric differences may be responsible for distinct behavioral aspects between these species. [ABSTRACT FROM AUTHOR]

Caviidae is one of the groups of rodents with the greatest ecomorphological disparity, and with currently three known lineages: Caviinae (cuises), Dolichotinae (maras), and Hydrochoerinae (capybaras). Caviinae include small caviids represented by three extant genera (Microcavia, Cavia, and Galea) and three fossils forms (Dolicavia, Palaeocavia, and Neocavia). In Argentina, the fossil record of Caviinae is continuous and abundant since the late Miocene. Neocavia, specifically, is represented by different species recorded in the late Miocene-Pliocene. Here, we describe a new species of Neocavia from the late Miocene-early Pliocene of the Cerro Azul Formation (La Pampa Province, Argentina), and provide a re-description of already known species (Neocavia lozanoi and "Neocavia depressidens"). Also, we perform a more comprehensive review of the genus and include the Neocavia species in a phylogenetic context within Caviinae. We analyze the main patterns of the evolution of the tympanic bullae within Caviidae, and infer about a possible occasional fossorial habit of Neocavia. The morphological and phylogenetic analyses indicate that Neocavia is more closely related to Dolicavia and Microcavia than to the other Caviinae, and confirm the monophyly of the genus, with at least two clearly differentiable species. Since this study cannot confirm the systematic position and validity of "N. depressidens", we suggest not to use this taxon as a biostratigraphic indicator. [ABSTRACT FROM AUTHOR]

As a non-threatened hystricognath rodent species, Spix ’s yellow-toothed cavies can be used as a model for the development of assisted reproductive techniques for the conservation of closely related species. The objective was to establish a functional protocol for cryopreservation of epididymal sperm from these cavies. Twelve sexually mature males, ∼2 y old and weighing ∼300 g, were euthanized. Sperm were recovered by retrograde flushing of the vas deferens and cauda epididymis with Tris extender. Thereafter, sperm were extended in Tris plus 20% egg yolk, with 3%, 6% or 9% glycerol or dimethyl sulfoxide (DMSO), placed in 0.25 mL straws and cryopreserved in liquid nitrogen. Sperm concentration, motility (using computer-assisted sperm analysis; CASA), plasma membrane integrity, osmotic response, morphology and sperm binding-ability were determined in fresh and frozen-thawed sperm. For most sperm endpoints, glycerol was a more desirable cryoprotectant than DMSO. Data (mean ± SEM) were similar with use of 3%, 6%, and 9% glycerol ( P  > 0.05) in osmotic response (40.66 ± 6.3%, 42.5 ± 7.1%, and 39.5 ± 5.0% respectably), and membrane integrity (55.17 ± 5.5%, 68.4 ± 4.1%, and 59.1 ± 4.9% respectably). Among concentrations assessed, the use of 6% glycerol resulted in the greatest ( P  < 0.05) post-thaw values for total motility (60.9 ± 4.4%), rapid subpopulation motility (27.7 ± 3.1%) and sperm-binding capability (227.0 ± 20.2). In conclusion, epididymal sperm from the Spix’s yellow-toothed cavies ( G. spixii ) are optimally cryopreserved in Tris extender with 6% glycerol and 20% egg yolk. [ABSTRACT FROM AUTHOR]

Copyright of Pesquisa Veterinaria Brasileira is the property of Colegio Brasileiro de Patologia Animal - CBPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The androgen/estrogen balance is essential for normal sexual development and reproduction in mammals. Studies performed herein investigated the potential for estrogen synthesis in cells of the testes of a hystricomorph rodent, Galea spixii. The study characterized the expression of the key enzymes responsible for estrogen and androgen synthesis, cytochromes P450 aromatase (P450arom), 17a-hydroxylase/17,20-lyase (P450c17) respectively, as well as the redox partner NADPH cytochrome P450 oxido-reductase (CPR) required to support electron transfer and catalysis of these P450s, by immunohistochemistry (IHC) and quantitative polymerase chain reaction (qPCR) analysis, throughout postnatal sexual development. Testes (immature, pre-pubertal, pubertal and post-pubertal) were collected, fixed for IHC (CYP19, CYP17 and CPR) and stored frozen for qPCR for the relevant gene transcripts (Cyp19a1 and Cyp17a1). Expression of P450c17 was significantly elevated at the pre-pubertal and pubertal stages. Based on IHC, P450c17 was expressed only in Leydig cell clusters. The expression of P450arom was detectable at all stages of sexual development of Galea spixii. IHC data suggest that estrogen synthesis was not restricted to somatic cells (Leydig cells/Sertoli cells), but that germ cells may also be capable of converting androgens into estrogens, important for testicular function and spermatogenesis. [ABSTRACT FROM AUTHOR]

Wild cavies from the taxonCavia aperea–Cavia porcellusare known for their extensive use of acoustic signals for communication including a courtship call that is a rarity in Mammalia. The genusCaviaincludes an insular species (Cavia intermedia) derived from a continental “asocial”Cavia magna. We hypothesized that the courtship call and all the other 12 acoustic signals previously described forC. aperea–C. porcelluswere synapomorphies of the genus and took the opportunity of recording the critically endangeredC. intermedia. Four field trips lasting 10 days were conducted in 2008 and 2009. After collecting and analysing nearly 350 sound files of 38 individuals, we found all the 12 calls of wild and domestic cavies previously described, including the courtship call, and a new call, a peep. Despite the presence of the peep, our description ofC. intermediaacoustic repertoire showed the evolutionary stability of the acoustic repertoire of this rodent genus of 6 species, even after domestication ofC. porcellusand 8000 years under insular selective forces inC. intermedia. We present a discussion about the communicative function ofCaviacalls in a comparative context and its repertoire size in accordance with the complexity level of sociality of this caviomorph rodent. [ABSTRACT FROM PUBLISHER]

Copyright of Therya is the property of Asociacion Mexicana de Mastozoologia, A. C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the present study was to characterize the epididymal sperm of Spix's yellow-toothed cavy ( Galea spixii) through two different recovery methods. Nine sexually mature males were euthanized and the complexes, testes-epididymis, were dissected. For each animal, one epididymis was processed by flotation method and the other was processed by retrograde flushing method, both using a TES-based buffered media. After recovery, we evaluated the sperm for motility, vigour, viability, functional membrane integrity and morphology. Morphometric data from the different sperm regions were evaluated by using an appropriate software. After recovery, both methods provide similar values for all the sperm parameters, aiming the recovery of more than 300 × 106 sperm, presenting >50% motile sperm, with normal morphology and functional membrane. The total sperm length in this sperm was 48.87 ± 0.1, and the sperm head presented 9.4%, on average. A notable characteristic was the prominent acrosome found in the G. spixii sperm. In conclusion, we demonstrate that either flotation or retrograde flushing methods are suitable for the recovery of sperm from cauda epididymis of Spix's yellow-toothed cavies. [ABSTRACT FROM AUTHOR]

2-Hydroxypropyl-Beta-Cyclodextrin (HPβCD) can be used to treat Niemann-Pick type C disease, Alzheimer’s disease, and atherosclerosis. But, a consequence is that HPβCD can cause hearing loss. HPβCD was recently found to be toxic to outer hair cells (OHCs) in the organ of Corti. Previous studies on the chronic effects of in vivo HPβCD toxicity did not know the intra-cochlear concentration of HPβCD and attributed variable effects on OHCs to indirect drug delivery to the cochlea. We studied the acute effects of known HPβCD concentrations administered directly into intact guinea pig cochleae. Our novel approach injected solutions through pipette sealed into scala tympani in the cochlear apex. Solutions were driven along the length of the cochlear spiral toward the cochlear aqueduct in the base. This method ensured that therapeutic levels were achieved throughout the cochlea, including those regions tuned to mid to low frequencies and code speech vowels and background noise. A wide variety of measurements were made. Results were compared to measurements from ears treated with the HPβCD analog methyl-β-cyclodextrin (MβCD), salicylate that is well known to attenuate the gain of the cochlear amplifier, and injection of artificial perilymph alone (controls). Histological data showed that OHCs appeared normal after treatment with a low dose of HPβCD, and physiological data was consistent with attenuation of cochlear amplifier gain and disruption of non-linearity associated with transferring acoustic sound into neural excitation, an origin of distortion products that are commonly used to objectively assess hearing and hearing loss. A high dose of HPβCD caused sporadic OHC losses and markedly affected all physiologic measurements. MβCD caused virulent destruction of OHCs and physiologic responses. Toxicity of HPβCD to OHC along the cochlear length is variable even when a known intra-cochlear concentration is administered, at least for the duration of our acute studies. [ABSTRACT FROM AUTHOR]

The aim of the present study was to characterise the ovarian preantral follicle (PF) population and to establish a solid surface vitrification (SSV) process using dimethyl sulfoxide (DMSO) as a cryoprotectant for preservation of ovarian tissue from yellow-toothed cavies (Galea spixii). Ovaries were fixed for PF population analysis or were subjected to the SSV process. The mean (± s.e.m.) PF population per ovarian pair was estimated to be 416.0±342.8. There were 140.0±56.0 (63.4%) and 125.0±58.0 (64.0%) primary follicles on the right and left ovaries, respectively. The proportion of this follicle category was significantly greater than that of other follicle categories (P<0.05). The diameter of follicles (123.7±18.3 µm), oocytes (50.1±5.0 µm) and nuclei (14.27±2.01 µm) was larger for secondary ones when compared with other PFs categories. Most PFs were morphologically normal (94.6%), with light microscopy identifying only a few atretic follicles (5.4%). After SSV, there was a reduction in the proportion of morphologically normal PFs compared with the non-vitrified group (69.5% vs 91.2%, respectively). Transmission electron microscopy revealed preservation of oocytes and granulosa cell membranes and the morphological aspect of follicles; the primary change observed in some vitrified PFs was the presence of vacuoles in the oocytes and granulosa cells cytoplasm and turgid mitochondria. In conclusion, the present study provides an estimative and characterization for the PF population in ovaries of G. spixii. Moreover, we report its PFs cryopreservation using an SSV process. [ABSTRACT FROM AUTHOR]

Climate changes, particularly the increase of temperature are among the main causes behind the decline of fertility in humans as well as animals. In this study, the effects of heat stress on some reproductive parameters of male cavies and mitigation strategies using guava leaves essential oil (GLEO) were studied. For this purpose, 40 male cavies aged 2.5–3 months and weighing between 348 and 446 g were divided into 4 groups of 10 animals each and subjected to the following temperatures: Ambient temperature (20–25 °C) for the control group, 35 °C for group 1, 45 °C for group 2 and 45 °C+100 µl GLEO/kg body weight, administered by gavage to animals for group 3. Exposure time of heat was 7 h per day for 60 days. Results reveal that the relative weights of testes, epididymis, vas deferens and seminal vesicles were hardly affected by the temperature levels considered (P>0.05). The mass and individual sperm motility was significantly lower (P<0.05) in cavies exposed to the temperature of 35 and 45 °C as compared with those which received GLEO and controls. The percentages of abnormal sperm and altered sperm DNA were higher in animals exposed to temperature of 35 and 45 °C as compared with the controls. The activity of superoxide dismutase significantly increased (P<0.05) in animals exposed to temperature of 45 °C and in those of 45 °C and orally treated with GLEO, compared with cavies exposed to temperature of 45 °C without receiving GLEO. The level of malondialdehyde was significantly increased (P<0.05) in animals exposed to temperature of 35 and 45 °C, whereas the level of nitric oxide was significantly lower (P<0.05) in exposed animals as compared with controls. It was concluded that the exposure of male cavies at 35 and 45 °C for 60 days induce heat stress that causes deterioration of sperm characteristics. These effects that can be mitigated by the administration of guava leaves essential oil. [ABSTRACT FROM AUTHOR]

Background: The social environment the mother experiences during pregnancy and lactation can powerfully influence the offspring's behavioural profile. Our previous studies in wild cavies show that two different social environments during pregnancy and lactation bring about different behavioural strategies of male offspring later in life: An unstable social environment leads to a behavioural camouflage strategy, hypothesised to be beneficial at times of socially challenging situations. A stable social environment during early phases of life, however, leads to an early reproduction strategy, expected to be more successful at times of social stability. In the present study, we observed the behavioural strategies of the two types of males in direct comparison in a socially challenging situation: Two adolescent males were placed simultaneously in an unknown social group consisting of one adult male and two females in a semi-naturalistic environment. Cortisol as well as testosterone concentrations and activity levels were compared. Furthermore, paternities were analysed after the males reached sexual maturity. We hypothesised that sons showing a behavioural camouflage strategy are better adapted to cope with this socially challenging situation compared to those displaying an early reproduction strategy. Results: At the beginning of the experiment, no differences in plasma cortisol concentrations between the males were found, both showed a highly significant increase due to the challenging situation. From day 5 until the end of the experiment (duration = 40 days) sons showing an early reproduction strategy had significantly higher plasma cortisol concentrations compared with those showing a behavioural camouflage strategy. Plasma testosterone concentrations did not differ significantly. Activity levels decreased significantly over time independently of the male's behavioural strategy. Both types of males did not sire offspring during the observation period. Conclusion: Higher cortisol values from day 5 until the end of the experiment in sons showing an early reproduction strategy indicate higher levels of stress in these males compared to those displaying a camouflage strategy. We conclude that the modulation of the males behavioural strategy due to an unstable social environment during early development facilitates the endocrine adaptation to a comparable social situation later in life. [ABSTRACT FROM AUTHOR]

Copyright of Iheringia. Série Zoologia is the property of Fundacao Zoobotanica do Rio Grande do Sul and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Kerodon rupestris are wild rodents bred in captivity in order to their conservation and development of researches. The aim of this study was describe the morphology of the tongue from eight animals by light microscopy and scanning electron microscopy, beyond macroscopic studies. The tongues of K. rupestris had 3.15 ± 0.28 cm of length; 1.0 ± 0.20 cm width at the root; 0.38 ± 0.10 cm width at the body; and, 1.10 ± 0.09 cm width at the apex. Thickness measurements were 0.50 ± 0.09 cm at the apex; 0.30 ± 0.10 cm at the body; and, 0.70 ± 0.10 cm at the root. The free apex had 0.50 ± 0.10 cm in length. The dorsal surface of the tongue contained the fungiform and filiform papillae at the apex and body; conical papillae and a pairs of vallate papillae at the root, and foliated papillae dorsolaterally positioned in the root region. The proper lamina of the dorsal surface of the tongue was composed by keratinized stratified squamous epithelium, in which lingual papillae were found; and, a rich network of skeletal striated muscle and non-modeled dense connective tissue, in which vessels, nerves, mucous and serous acini and their respective ducts were found. In summary, dorsal surface of the tongue of K. rupestris had filiform and conical papillae with mechanical function, and, fungiform, vallate and foliated papillae with taste buds responsible by gustatory function. Moreover, the tongue of these animals showed some peculiarities as the eminence on the apex in sagittal plane, which needs further studies.

The southern distribution of the small cavies Galea leucoblephara and Microcavia australis is reviewed. It has been enriched through the addition of 36 new locality records for G. leucoblephara and 176 for M. australis. Both caviomorph rodents are widespread in Patagonia - the former occurs in the northern portion of the territory, whereas the latter is recorded up to the Strait of Magellan. The reference of Patagonian Galea populations to leucoblephara is still subject to confirmation. Therefore, the status of negrensis must be addressed in future studies. For southern Microcavia australis populations, a rich subspecifical scenario is proposed, including the names australis, kingii, and nigriana. The alpha taxonomy of this cavy needs a fresh approach that is based on a larger sample set coupled with the analysis of molecular markers. [ABSTRACT FROM AUTHOR]

ABSTRACT Present research was carried out in order to perform the monitoring of development, recognizes the type of tissue and describes histological and cellular changes of the vaginal closure membrane (VCM) throughout pregnancy in Galea spixii. The results showed that at 20 days of gestation (DG), the VCM occludes completely the external vaginal ostium. Microscopically, the VCM presented juxtaposed cells, derived from the stratum germinative of the stratified epithelium of vaginal mucosa at 20 DG and areas with cell clusters with the presence of intercellular spaces in the final stages of pregnancy (40-50 DG). At 0 DG, the stratified epithelium of vaginal mucosa presented all strata but at 20 DG presented stratified epithelium without the stratum corneum and stratum granular and showed communicant junctions by desmosomes and interdigitations in the cell membrane compound the VCM. Gradually from 40 to 50 DG the stratum germinative became barely perceptible. Many cells showed apoptotic nuclei and emerged many intercellular spacing. So, the interdigitations and desmosomes were not observed. Here, it was demonstrated for the first time that the VCM is formed after the extinction of the stratum granular and corneum of the vaginal mucosa epithelium, with the proliferation of the cells of stratum germinative and communication and junction through desmosomes and interdigitations of these cells. At the end of pregnancy, cellular apoptosis; the spread of stratum germinative; and, absence of cellular communication and junction may be responsible for the weakening of the VCM and may assist the process of rupture of this membrane. Microsc. Res. Tech. 79:359-364, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

A rocky habitat, in its broadest sense, may be described as any locality that contains boulders, rocks, scree, pebbles, outcrops, cliffs, or caves. In these habitats, mammals find shelter sites that they use as nesting sites or dens to raise their young in a stable microclimate that is relatively secure from predators. The aim of this study was to characterize and evaluate the microhabitat selection by the southern mountain cavy (Microcavia australis Geoffroy and d'Orbigny) in a rocky habitat. This rodent selected the highest and deepest crevices, which provided them with a more stable microenvironment than outside. The present study is the first to report a southern mountain cavy population associated with a rocky habitat, suggesting a strong plasticity to inhabit a variety of habitats, as indicated by its wide distribution. [ABSTRACT FROM AUTHOR]

Background: Domestic cavies (Cavia porcellus) are increasingly reared in rural areas of Cameroon for meat and income generation. Unfortunately, health constraints due to various pathogens including parasites stand as one of the major obstacles to the development of cavy industry in the country. The main objective of this study was to investigate the species of gastrointestinal parasites in cavy husbandry in the western highlands of Cameroon and to detect external parasites in those animals affected with dermatological disorders. Methods: Pooled fecal samples were collected from 62 privately-own farms, as well as individual fecal samples from 21 animals at the Teaching and Research Farm of the University of Dschang, and examined for parasite eggs and oocysts/cysts. Ectoparasites were also collected from cavies and identified. Results: The overall infection rate with both helminthes and arthropods was 40.3 %. Ectoparasites were found in 19 out of 62 farms (30.6 %) while 12.9 % of farms were infected with helminthes. Eggs of Graphidium strigosum (8.1 %), Trichostrongylus sp. (3.2 %) and Paraspidodera uncinata (3.2 %) were found at farm level. Oocysts of Eimeria caviae and eggs of Paraspidodera uncinata were found in 14.3 and 9.5 % of examined animals respectively. Concerning ectoparasites, Cordylobia anthropophaga and Pulex sp. were observed in 25.8 % and 6.6 % of farms respectively. Conclusion: The parasites are apparently composed of host-specific species in the original habitat (South America) and species acquired later from other mammals. These parasites are either deleterious to cavy health or zoonotic. Preventive measures should be put in practice to avoid their presence on farms due to their harmful effect on cavy rearing. [ABSTRACT FROM AUTHOR]

Revisé la información sobre la dieta de 25 especies de micromamíferos que habitan en Chile, y que ha sido publicada en once artículos científicos. Dividí el aporte de cada ítem alimentario en cinco categorías: hongos, tejido vegetal, semillas, frutos e insectos. Esto me permitió representar la información documentada en la forma de diagramas De Finetti en el cual la posición trófica de una especie se representa por un punto en un triángulo equilátero. Para determinar con un criterio estadístico las líneas de corte dentro del diagrama De Fenetti realicé análisis de correspondencia. Este análisis permitió agrupar las especies en seis grupos de categorías tróficas: herbívoro, insectívoro, omnívoro, seminívoro-frugívoro, herbívoro/seminívoro-frugívoro, herbívoro/insectívoro. Los hábitos alimentarios de las especies pertenecientes a la familia Muridae incorporan dietas mixtas con una fluctuación porcentual de cada ítem, cambiando sus hábitos alimentarios significativamente entre localidades. Las especies A. bennetti, A. cinerea, A. andinus, C. lanigera, L. viscacia, M. niata, O. bridgesi y Thylamys elegans incorporan dietas constituidas solo por un ítem, cuya representatividad fue mayor al 90 %.I reviewed dietary information of 25 species of small mammals inhabiting Chile and published in 11 scientific articles. I divided the contribution of each food item in five categories: fungi, vegetation, seeds, fruits and insects. This approach allowed me to represent the information documented in the form of De Finetti diagrams, in which the trophic position of a species is represented by a point in an equilateral triangle. Through correspondence analysis, I determined statistically the groups inside the diagram De Fenetti. This analysis allowed me to group the species in seven trophic categories: herbivorous, insectivorous, omnivorous, granivorous-frugivorous, herbivorous/granivorous-frugivorous, herbivorous/insectivorous. Food habits of species in Muridae family incorporate mixed diets with a percentage fluctuation of each item, changing its food habits significantly among localities. The species A. bennetti, A. cinerea, A. andinus, C. lanigera, L. viscacia, M. niata, O. bridgesi and Thylamys elegans incorporate monospecific diets with representativeness of 90 % of consumed item

To investigate the origin and diversity of domestic guinea-pigs Cavia porcellus (Linnaeus, 1758; Rodentia, Caviidae), we sequenced the mitochondrial cytochrome b gene of 12 domestic and 10 wild specimens from six species, including the two presumed as ancestral to the domestic one: Cavia tschudii and Cavia aperea. All maximum parsimony and maximum likelihood analyses grouped C. porcellus with C. tschudii (mean K2P distance = 3.2 %); best trees had 609 steps (CI = 0.796; Bremer support Index (SI) = 28), and a _Ln = 4419.52, with 100 % and 97 % bootstrap support respectively. This clade, supported by three substitutions and 96 % bootstrap, is also obtained in the cladistic analysis of corresponding amino acids. When the C. aperea node was forced to join C. porcellus, these trees were consistently longer, less likely and robust, and with less defining characters than the optimal one. All C. porcellus sequences also clustered in a node defined by 15 substitutions. The sub-node containing animals from city markets, pet shops and laboratories was characterized by four substitutions (one non-silent, SI = 7, and 91 % bootstrap). Some South American C. porcellus, called "criollos" (creoles) by local breeders, were more diverse. Probably, a particular clade from southern Peru and Chile may represent a pre-Columbian lineage. Mean K2P distance between C. tschudii and C. aperea was rather large, 7.7 %. Cavia appeared as a robust node (100 % bootstrap). These results indicate that C. tschudii is the species most closely related to C. porcellusPara investigar el origen y la divergencia de los cuyes domésticos Cavia porcellus (Linnaeus, 1758; Rodentia, Caviidae), secuenciamos el gen mitocondrial para citocromo b de 12 especímenes domésticos y 10 silvestres de seis especies, incluyendo las dos que se presumen como ancestro de la doméstica: C. tschudii y C. aperea. Todos los análisis de máxima parsimonia y máxima verosimilitud agruparon a C. porcellus con C. tschudii (promedio de distancias K2P = 3,2 %); los mejores árboles tenían 609 pasos (CI = 0,796; Índice de Apoyo de Bremer (SI) = 28), y un _Ln = 4.419,52; con apoyos de remuestreo de 100 % y 97 % respectivamente. Dicho clado también apareció en el análisis cladístico de los aminoácidos correspondientes, apoyado por tres sustituciones y 96 % remuestreo. Cuando el nodo de C. aperea fue forzado a unirse al de C. porcellus, estos árboles fueron consistentemente más largos, menos probables y robustos, y con menos caracteres definitorios que el óptimo. Todas las secuencias de C. porcellus se agruparon también en un nodo definido por 15 sustituciones. El subnodo con animales de mercados de ciudad, tiendas de mascota y laboratorios se caracterizó por cuatro sustituciones (una no silenciosa, SI = 7 y 91 % remuestreo). Los C. porcellus sudamericanos, llamados "criollos" por los criadores locales, son más diversos. Probablemente, un clado del sur del Perú y Chile representa un linaje precolombino. La distancia K2P promedio entre C. tschudii y aperea fué más bien grande, 7,7 %. Cavia apareció como un nodo robusto (100 % remuestreo). Estos resultados indican que C. tschudii es la especie más cercanamente relacionada a C. porcellus.

Objective: Rodents have a wide diversity of morphologies of lingual papillae, and their description enables a better comprehension of evolution and feeding habits. This investigation aimed to characterize the morphology of lingual papillae of the Spix's yellow-toothed cavy, a Brazilian species adapted to a hot and dry climate. Methods: Four tongues were dissected and analyzed under scanning electron microscopy to reveal the epithelial surface and connective tissue core (CTC). The research was approved by SISBio (n° 48585-1) and UFERSA Animal Use Ethics Committee (n° 20/2021). Results: The tongue was anatomically divided into apex, body, and root (Fig. 1). The samples present filiform, fungiform, foliate, and vallate papillae. After epithelial maceration, the respective CTC was revealed. In the apex and body were revealed trifid filiform papillae with a tricuspid-like CTC, fungiform papillae were dome-like and had a round-like CTC. On the edge of lingual prominence were present robust filiform papillary lines, and the CTC of the primary line had a U-shaped morphology, while the second line had a C-shaped aspect. On the lateral surface of the prominence, the foliate papillae had clefts and were contiguous to laterally-placed fungiform papillae, CTC of the foliate papillae had laminar projections and the fungiform was round-like. The caudal region had a pair of vallate papillae, and CTC had several laminar projections. Conclusion: The tongue of Spix's yellow toothed-cavy had species-specific adaptations. The presence and organization of the robust filiform papillary lines and fungiform laterally-placed were new characteristics for the records of the Rodentia anatomy. [ABSTRACT FROM AUTHOR]

Background The neuromechanical processes involved in the formation and propulsion of fecal pellets remain incompletely understood. Methods We analyzed motor patterns in isolated segments of the guinea-pig proximal and distal colon, using video imaging, during oral infusion of liquid, viscous material, or solid pellets. Key Results Colonic migrating motor complexes ( CMMCs) in the proximal colon divided liquid or natural semisolid contents into elongated shallow boluses. At the colonic flexure these boluses were formed into shorter, pellet-shaped boluses. In the non-distended distal colon, spontaneous CMMCs produced small dilations. Both high- and low-viscosity infusions evoked a distinct motor pattern that produced pellet-shaped boluses. These were propelled at speeds proportional to their surface area. Solid pellets were propelled at a speed that increased with diameter, to a maximum that matched the diameter of natural pellets. Pellet speed was reduced by increasing resistive load. Tetrodotoxin blocked all propulsion. Hexamethonium blocked normal motor patterns, leaving irregular propagating contractions, indicating the existence of neural pathways that did not require nicotinic transmission. Conclusions & Inferences Colonic migrating motor complexes are responsible for the slow propulsion of the soft fecal content in the proximal colon, while the formation of pellets at the colonic flexure involves a content-dependent mechanism in combination with content-independent spontaneous CMMCs. Bolus size and consistency affects propulsion speed suggesting that propulsion is not a simple reflex but rather a more complex process involving an adaptable neuromechanical loop. [ABSTRACT FROM AUTHOR]