The Dmanisi Equus: Systematics, biogeography, and paleoecology.

The Equus datum has been established as a geochronologic 'instantaneous' migratory event of a North American Equus species into Eurasia at the beginning of the Pleistocene (2.58 Ma). A remarkable radiation of Equus followed across Eurasia and Africa. Dmanisi includes excellent remains of Equus, well calibrated between 1.85 and 1.76 Ma. Our morphologic and morphometric analyses of the augmented Dmanisi Equus sample support the co-occurrence of Equus stenonis and Equus altidens in the sequence. Dmanisi E. stenonis is found to be morphologically similar to the European E. stenonis populations and represents the best well-dated easternmost occurrence of this species in Eurasia. The Dmanisi E. altidens represents the oldest well-calibrated occurrence of this species in Western Eurasia. Our analyses demonstrate that E. altidens extended its range westward from west Asia to Greece, Germany, Italy, Spain, and possibly France. Our results do not support distinguishing multiple subspecies of E. altidens, including E. altidens altidens, E. altidens granatensis and E. stenonis mygdoniensis. The Dmanisi cranial and postcranial samples exhibit morphologies close both to extant hemiones and zebras. Equus altidens is believed to have been well adapted to newly emergent arid environments in western Eurasia during the late Early and early Middle Pleistocene. The first occurrence of E. altidens at Dmanisi marks an important turnover in the horse communities of the late Early Pleistocene, with a dispersion of this species from West Asia to West Europe ca. 1.8 Ma.

Evolution of Old World Equus and origin of the zebra-ass clade.

Evolution of the genus Equus has been a matter of long debate with a multitude of hypotheses. Currently, there is no consensus on either the taxonomic content nor phylogeny of Equus. Some hypotheses segregate Equus species into three genera, Plesippus, Allohippus and Equus. Also, the evolutionary role of European Pleistocene Equus stenonis in the origin of the zebra-ass clade has been debated. Studies based on skull, mandible and dental morphology suggest an evolutionary relationship between North American Pliocene E. simplicidens and European and African Pleistocene Equus. In this contribution, we assess the validity of the genera Plesippus, Allohippus and Equus by cladistic analysis combined with morphological and morphometrical comparison of cranial anatomy. Our cladistic analysis, based on cranial and postcranial elements (30 taxa, 129 characters), supports the monophyly of Equus, denies the recognition of Plesippus and Allohippus and supports the derivation of Equus grevyi and members of the zebra-ass clade from European stenonine horses. We define the following evolutionary steps directly relevant to the phylogeny of extant zebras and asses: E. simplicidens-E. stenonis-E. koobiforensis-E. grevyi -zebra-ass clade. The North American Pliocene species Equus simplicidens represents the ancestral stock of Old World Pleistocene Equus and the zebra-ass clade. Our phylogenetic results uphold the most recent genomic outputs which indicate an age of 4.0-4.5 Ma for the origin and monophyly of Equus.

A novel A > G polymorphism in the intron 2 of TBX3 gene is significantly associated with body size in donkeys.

T-box transcription factor 3 (TBX3) gene encodes a transcriptional suppressor and plays an important role in embryonic development, which belongs to the T-box family. TBX3 also has been found to be associated with body size traits in horse that is a relative of donkey. Therefore, TBX3 is considered as a promising candidate gene for economic traits of donkey. This study aimed to reveal the significant variation of TBX3 gene in Dezhou donkey and explores the relationship between genotypes and body sizes. In this study, an A > G mutation was found in the intron 2 of TBX3 gene by sequencing, and three genotypes (AA, GG and AG) were identified in 380 Dezhou donkey individuals with Tm-shift method. Association analysis illustrated that there were significant differences between AA and GG genotype in body length, body height, chest depth, chest circumference, body weight, hucklebone width and rump length. Our results demonstrated that the polymorphism of TBX3 is significantly associated with body size traits, which can serve as a marker to improve donkey production performance.

Radiographic parameters of the digit in a cohort population of Amiata donkeys.

Background: The most common musculoskeletal conditions reported in donkeys are related to the foot. Radiographic examinations are clinically important in the diagnosis of foot abnormalities and are commonly used. However, few studies have been conducted to establish the normal radiographic appearance of a donkey's foot. Aim: To determine the radiographic features of the front digit in healthy Amiata donkeys. Methods: Radiographic examinations were performed on 56 forefeet of 28 Amiata donkeys. Three radiographic views of each front foot were taken: lateromedial, dorsopalmar and dorso-65°proximal/palmarodistal oblique. Seventeen angular and linear radiographic parameters and the crena solearis were evaluated in all forefeet, and 18 morphometric parameters were evaluated in 16 out of 56 forefeet. Statistical analysis was carried out on all the measures assessed. Results: The radiographic appearance of the forefoot was ascertained, and data were reported as median ± standard error, minimum and maximum values. No statistical differences were obtained between the right and left forefeet. Conclusion: The normal baseline parameters of the forefeet of Amiata donkeys were recorded and described and compared with other donkey breeds and horses. The findings highlighted that the donkey breed affects the radiographic parameters of the digit.

Donkeys in transition: changing use in a changing world / Jumentos em transição: alterações do seu uso num mundo em mudança

Donkeys have a long history in the development of human societies. Typically referred to as a beast of burden, traditional uses for donkeys have included the transportation of goods and people, use in agricultural and forestry activities, to access water, and provide citizens in low- and middle-income countries a means of making an income for communities. However, the rise of mechanization, the development of modern farming techniques, and the increasing availability of motorized vehicles have led to donkeys and mules becoming redundant from traditional roles in many parts of the world. We provide examples of where donkeys have successfully transitioned from traditional roles to new, non-traditional roles in Europe and North America, and demonstrate that, although the roles and use of donkeys and mules are changing in a rapidly developing world, we can learn lessons from the past and apply them to current challenges. As the need for working equids declines in transport and agriculture, they still hold great value for recreational, therapeutic, and environmentally friendly methods of animal traction.(AU)

Os jumentos têm uma longa história no desenvolvimento das sociedades humanas. Normalmente referidos como bestas de carga, seus usos tradicionais incluem o transporte de pessoas e bens, atividades agrícolas e florestais, acesso a água, assim como oferecer uma forma de rendimento para comunidades em países de rendimento baixo e médio. No entanto, o aumento da mecanização, o desenvolvimento de técnicas agrícolas modernas e maior disponibilidade de veículos motorizados fizeram com que os jumentos e os muares se tornassem desnecessários nos seus papéis tradicionais em muitas partes do mundo. Neste artigo os autores fornecem exemplos onde os jumentos fizeram a transição, com sucesso, dos papéis tradicionais para novos papéis não tradicionais, tanto na Europa como na América do Norte; e demonstramos que, embora o papel e o uso de jumentos e muares estejam mudando num mundo em rápido desenvolvimento, podemos aprender lições com o passado e aplicá-las aos desafios atuais. À medida que diminui a necessidade de equídeos de trabalho no transporte e na agricultura, eles ainda têm grande valor no que toca a fins recreativos, terapêuticos e ecológicos no uso de tração animal.(AU)

Donkey skin trade: is it sustainable to slaughter donkeys for their skin? / Comércio de pele de jumentos: é sustentável abater jumentos para o uso de sua pele?

Donkeys (Equus asinus) face a global crisis. The health, welfare, and even survival of donkeys are being compromised as the demand for their skins increases. It is driven by the production of ejiao, a traditional Chinese remedy believed by some to have medicinal properties. It is estimated that the ejiao industry currently requires approximately 4.8 million donkey skins per year. Since there is no productive chain for donkey skin production outside of China, the activity is extractive and has resulted in the decimation of donkeys. Gestation is 12 months in donkeys, increasing the risk of extinction if such practices are not controlled. In this scenario, the donkeys are collected (purchased for low prices, stolen, and collected from the side of the roads) and are then often transported for long distances, usually without water, food, or rest. The trade, in Brazil, poses significant biosecurity risks, particularly because examinations are rarely conducted and therefore infectious diseases, such as glanders and infectious anemia, remain undetected. Furthermore, in chronic stress situations, the immune system is suppressed, increasing the biosecurity risk, especially because donkeys are a silent carrier of diseases. Rarely there is traceability with animals from different origins being put together in "fake farms", before being delivered to slaughterhouses. The opportunistic strategy of collecting animals, or buying for low prices, keeping them without access to food and veterinary assistance, is what makes this trade profitable. Our experience in donkey welfare and the global skin trade suggest that it will be enormously challenging and cost-prohibitive to run a trade at the standards required to be considered humane, sustainable, and safe. Although donkeys are being blamed for the involvement in road accidents, it is not an ethical solution to maintain this trade as an alternative. Moreover, the ecological role of donkeys in native ecosystems has not been elucidated, and some studies indicate they could even have a positive effect. Regardless of the future the donkeys will have; we must guarantee a life with the least dignity to the animals under our responsibility.(AU)

Os jumentos (Equus asinus) estão enfrentando uma crise global. A saúde, o bem-estar e até a sobrevivência dos jumentos estão sendo comprometidos à medida que a demanda por suas peles aumenta. A atividade é impulsionada pela produção de ejiao, um remédio tradicional chinês que algumas pessoas acreditam possuir propriedades medicinais. Estima-se que a indústria de ejiao demande atualmente cerca de 4,8 milhões de peles de jumento por ano. Uma vez que não existe uma cadeia produtiva fora da China, a atividade é extrativista e resultou na drástica redução das populações. A gestação dos jumentos é de 12 meses, aumentando o risco de extinção se tais práticas não forem controladas. Neste cenário, os jumentos são recolhidos (comprados a preços baixos, roubados e recolhidos à beira das estradas) e são frequentemente transportados para longas distâncias, normalmente sem água, comida ou descanso. O comércio no Brasil apresenta riscos significativos de biossegurança, principalmente porque os exames raramente são realizados e, portanto, doenças infecciosas, como mormo e anemia infecciosa equina, permanecem sem detecção. Além disso, em situações de estresse crônico, o sistema imunológico é suprimido, aumentando o risco de biossegurança, principalmente porque os jumentos são portadores silenciosos de doenças. Raramente há rastreabilidade, e os animais de diferentes origens acabam sendo colocados em "fazendas fantasma", antes de serem entregues aos abatedouros. A estratégia oportunista de coletar animais, ou comprar por preços irrisórios, mantendo-os sem acesso a alimentação e assistência veterinária, é o que torna esse comércio lucrativo. Nossa experiência em bem-estar de jumentos e no comércio global de peles sugere que será extremamente desafiador e com custo proibitivo administrar um comércio dentro dos padrões exigidos para ser considerado humano, sustentável e seguro. Embora os jumentos sejam responsabilizados pelo envolvimento em acidentes rodoviários, não é uma solução ética manter este comércio como uma alternativa. Além disso, o papel ecológico dos jumentos nos ecossistemas nativos não foi elucidado, e alguns estudos indicam que eles podem até ter um efeito positivo. Independentemente do futuro que os jumentos terão, devemos garantir uma vida com o mínimo de dignidade aos animais sob nossa responsabilidade.(AU)

Influence of age, body weight and season on testicular and epididymis biometrics in donkeys (Equus asinus) / Influencia de la edad, el peso corporal y la estación en la biometría testicular y el epidídimo en burros (Equus asinus)

SUMMARY: The objective of this present investigation was undertaken to study the testicular and epididymal biometrical characteristics in Algerian donkeys throughout the year according to age, body weight and seasonal changes. The study was conducted from February 2019 to January 2020. A total of 24 sexually mature donkeys (Equus asinus) were selected randomly. The testis and epididymis were collected after slaughter of donkeys and separated from the conjunctive and adherent tissues. The epididymis has been carefully removed at the testicular junction. In total, 10 biometric measures were selected and performed. Our results revealed that there are significant differences (P<0.05) between groups in most biometrics values. All biometric parameters varied throughout the year and were affected by the season. Significant differences of the GSI and SC values (P<0.05) were observed in different age groups and seasons. On the other hand, no significant differences were observed between the body weight categories of donkeys. The analysis of the correlation coefficients between the biometric values shows high positive correlations, ranged between 0.98 and 0.72 (P<0.001). There was a high positive correlation between age and all the parameters, ranged from 0.85 to 0.61 (P<0.001). However, there were low negative correlations between season and; testicular and epididymal biometrics. It is the first investigation that describes the male reproductive organs in donkeys of the Algerian race (Equus asinus), on the basis of biometric testicular and epididymal measurements. Our results showed that the essential differences were noted between some biometric parameters and the age, season and body weight of donkeys. In addition, the correlation coefficients were supported between biometric measurements and these factors. However, other approaches are necessary to undertake, such as histology of reproductive organs and hormone measurement, for a deeper understanding of the physiology of reproduction in donkeys.

RESUMEN: El objetivo de esta investigación fue estudiar las características biométricas testiculares y epididimarias en burros Argelinos durante todo el año de acuerdo con la edad, el peso corporal y los cambios estacionales. El estudio se realizó entre febrero de 2019 y enero de 2020. Se seleccionó al azar un total de 24 burros sexualmente maduros (Equus asinus). Los testículos y el epidídimo se recogieron después del sacrificio de los burros y se separaron de los tejidos conjuntivos y adherentes. El epidídimo se eliminó cuidadosamente en la unión testicular. En total, se seleccionaron y realizaron 10 medidas biométricas. Nuestros resultados revelaron que existen diferencias significativas (P <0,05) entre los grupos en la mayoría de los valores biométricos. Todos los parámetros biométricos variaron a lo largo del año y se vieron afectados por la temporada. Se observaron diferencias significativas de los valores de GSI y SC (P <0,05) en diferentes grupos de edad y estaciones. Por otra parte, no se observaron diferencias significativas entre las categorías de peso corporal de los burros. El análisis de los coeficientes de correlación entre los valores biométricos muestra altas correlaciones positivas, entre 0,98 y 0,72 (P <0,001). Hubo una alta correlación positiva entre la edad y todos los parámetros, que varió de 0,85 a 0,61 (P <0,001). Sin embargo, hubo bajas correlaciones negativas entre temporada y biometría testicular y epididimaria. Es la primera investigación que describe los órganos reproductores machos en burros de la raza Argelina (Equus asinus), sobre la base de mediciones biométricas testiculares y epididimarias. Nuestros resultados mostraron que se observaron las diferencias esenciales entre algunos parámetros biométricos y la edad, la estación y el peso corporal de los burros. Además, los coeficientes de correlación fueron compatibles entre las mediciones biométricas y estos factores. Sin embargo, son necesarios otros enfoques, como la histología de los órganos reproductivos y la medición de hormonas, para una mayor comprensión de la fisiología de la reproducción en burros.

Comparison of right and left common carotid arteries of horses and mules by two-dimensional ultrasound and Doppler flow / Comparação das artérias carótidas comuns direita e esquerda dos gêneros de equinos e muares por ultrassonografia bidimensional e Dopplerfluxométrico

In ultrasonography, the bi-dimensional mode (B-mode) allows the morphological and morphometric evaluation of several types of organs and tissues, while the Doppler mode allows the hemodynamic evaluation. In humans, the Doppler evaluation is routinely used in the assessment of important arteries and veins, such as the carotid arteries and jugular veins, with significant differences between genres and sides. However, in veterinary medicine, this diagnostic method is not yet well established in the evaluation of the carotid arteries, with only few reports in domestic horses. This study aims to compare the right and left common carotid arteries of domestic horses and mules using bi-dimensional and Doppler ultrasound evaluation. The common carotid arteries from 10 domestic horses (five males and five females) and 10 mules (five males and five females) were evaluated. The following variables were measured at three different portions (cranial, middle and caudal): diameter, intima-media thickness (IMT), resistivity index (RI), pulsatility index (PI), peak of systolic velocity (pSV) and final diastolic velocity (fDV). No significant differences were observed in the bi-dimensional variables (diameter and IMT) between the common carotid arteries of horses and mules, regardless of gender (p>0.05). In Doppler mode, there were no significant differences between carotid values in male and female horses (p> 0.05). In the mules, it was only possible to observe differences between the RI and PI values (p<0.05), being higher on the left side (0.81 and 2.04 respectively), and the fDV (p<0.05) higher, on the right side (14.35) in males. As for females, there was only in fDV (p<0.05), with the upper right side (23.16). Diameters and IMT do not differ between sides in horses and mules in B-mode ultrasound. Spectral Doppler in horses does not differ between sides, regardless of gender. As for mules, males differ in RI, PI and fDV between sides, while females differ only in fDV.(AU)

Na ultrassonografia, o modo bidimensional (modo B) permite a avaliação morfológica e morfométrica de vários tipos de órgãos e tecidos, enquanto o modo Doppler permite a avaliação hemodinâmica. Em humanos, a avaliação com Doppler é usada rotineiramente na avaliação de artérias e veias importantes, como as artérias carótidas e veias jugulares, com diferenças significativas entre gêneros e lados. No entanto, em medicina veterinária, este método diagnóstico ainda não está bem estabelecido na avaliação das artérias carótidas, com apenas poucos relatos em equinos domésticos. Este estudo tem como objetivo comparar as artérias carótidas comuns direita e esquerda de equinos e mulas domésticos, utilizando a avaliação bidimensional (modo B) e por ultrassonografia Doppler espectral. Avaliaram-se as artérias carótidas comuns de 10 equinos domésticos (cinco machos e cinco fêmeas) e 10 mulas (cinco machos e cinco fêmeas). As seguintes variáveis foram medidas em três porções diferentes (cranial, médio e caudal): diâmetro, espessura íntima-média (IMT), índice de resistividade (RI), índice de pulsatilidade (PI), pico de velocidade sistólica (pSV) e velocidade diastólica final (fDV). Não foram observadas diferenças significativas nas variáveis bidimensionais (diâmetro e IMT) entre as artérias carótidas comuns de cavalos e muares, independentemente do gênero (p>0,05). No modo Doppler, não houve diferenças significativas entre os valores para carótidas em equinos machos e fêmeas (p>0,05). Nos muares, só foi possível observar diferenças entre os valores de RI e PI (p<0,05), sendo maiores no lado esquerdo (0,81 e 2,04 respectivamente), e o fDV (p<0,05) superior no lado direito (14,35) nos machos. Quanto as fêmeas, houve apenas no fDV (p<0,05), sendo o lado direito superior (23,16). Os diâmetros e IMT não diferem entre os lados em equinos e muares na ultrassonografia modo B. Já o Doppler espectral nos equinos não difere entre os lados, independentemente do gênero. Quanto aos muares, os machos diferenciam no IR, IP e fDV entre os lados, enquanto as fêmeas apenas para fDV.(AU)

Comparação das artérias carótidas comuns de equinos e muares por ultrassonografia modo-B e Doppler espectral e a relação com a massa corpórea / Comparison of the common carotid arteries of horses and mules by B-mode and Doppler spectral ultrasonography and the relation with body mass

A ultrassonografia convencional e o Doppler espectral nas artérias carótidas comuns em equinos e muares são considerados escassos, diferentemente do que ocorre na medicina humana. Este trabalho propôs comparar as artérias carótidas comuns de equinos e muares por ultrassonografia modo-B e Doppler espectral, além de verificar as diferenças dessas variáveis entre os gêneros desses animais e a relação com a massa corpórea. Foram avaliados os seguintes parâmetros: massa corpórea, diâmetros das artérias, espessura da camada íntima-média (EIM), índice de resistividade (IR), índice de pulsatilidade (IP), velocidade sistólica (VS), velocidade diastólica (VD) e velocidade média (VM). Salvo a massa corpórea, esses parâmetros foram obtidos de três regiões (cranial, médio e caudal) e submetidos à análise conjuntamente. Os diâmetros das artérias carótidas comuns são diferentes entre equinos e muares, com valores menores nos equinos. O IR, o IP, a VS e a VM diferiram entre equinos e muares, sendo maiores nos equinos, e a VD superior nos muares. Não foi observada diferença das variáveis do modo-B e Doppler entre gêneros nos equinos, diferentemente dos muares, cujos machos apresentaram valores maiores do diâmetro, do IR e do IP, mas menores da VS e da VM. A massa corpórea não influenciou as variáveis do modo-B, independentemente do gênero, mas apresenta correlação significativa nas variáveis do modo Doppler. As artérias carótidas comuns de equinos e muares são diferentes pelos exames ultrassonográficos modo-B e Doppler espectral. O gênero não influencia no modo-B e no Doppler nos equinos, porém influencia parcialmente nos muares. A massa corpórea de equinos e de muares, independentemente do gênero, não tem associação com as variáveis do modo-B, apenas com o Doppler.(AU)

Conventional ultrasound and spectral Doppler in the common carotid arteries in horses and mules are considered scarce, different from human medicine. The aim of this study was to compare the common carotid arteries of horses and mules by B-mode ultrasonography and spectral Doppler ultrasonography, as well as to verify the differences of these variables between their genders and the relation with body mass. The following parameters were evaluated: body mass, artery diameter, intima-media thickness (EIM), resistivity index (IR), pulsatility index (IP), systolic velocity (VS), diastolic velocity (VD) and average velocity (VM). Besides the body mass, the other variables were obtained from three regions (cranial, medium and caudal) and analyzed together. The diameters of the common carotid arteries are different between horses and mules, being smaller in horses. The IR, IP, VS and VM differed between horses and mules, being higher in the horses, but the VD was higher in mules. No difference in the variables in B-mode and Doppler between gender were observed in horses, different from mules, in which the diameters, IR and IP values were higher in males and the VS and VM was higher in females. Body mass did not influence B-Mode, both for horses and mules. A significant correlation was observed for Doppler. The common carotid arteries of horses and mules are different by ultrasound scans B-mode and spectral Doppler. Gender does not influence the B-Mode and Doppler variables in horses, but can in mules. The body mass of horses and mules, regardless of gender, is not associated with B-mode variables, but with Doppler variables.(AU)

Cross-anatomical, radiographic and computed tomographic study of the stifle joint of donkeys (Equus africanus asinus).

The present investigation was conducted to provide a full anatomical description of the stifle joint of donkeys using 3D computed tomography imaging technique, in addition to the classic anatomical methods, such as radiography and cross-anatomical sectioning. The radiography and CT imaging of stifle joint were interpreted in comparison with cross-sectional anatomical sections. Volume-rendering reconstruction techniques (3D-CT) were used to describe the anatomical structure of stifle joint. The used twelve adult healthy donkeys were free from any musculoskeletal disorders. Four donkeys were used for the gross anatomical observations, four for CT and radiography and two live animals for determination the site of injections. The results of this study revealed that the complex stifle joint was formed from three joints: femorotibial, femoropatellar and proximal tibiofibular. The articular surfaces were described for each joint, and the synovial layer of the articular capsule formed three main joint sacs: femoropatellar, medial femorotibial and lateral femorotibial sacs. The ligaments of stifle joint were recorded, and meniscal ligaments included cranial and caudal ligaments of medial and lateral menisci and meniscofemoral ligament of lateral meniscus. The cruciate ligaments were also described and they included the cranial and caudal cruciate ligaments, while the patellar ligament included the medial, middle and lateral patellar ligaments. The arterial supply and the site of injection of the stifle joint were described. In conclusion, the 3D reconstruction CT provided well-defined baseline reference image for the stifle joint of donkeys for anatomist, radiologist, surgeons and researchers.

How flat can a horse be? Exploring 2D approximations of 3D crania in equids.

Quantitative analyses of morphological variation using geometric morphometrics are often performed on 2D photos of 3D structures. It is generally assumed that the error due to the flattening of the third dimension is negligible. However, despite hundreds of 2D studies, few have actually tested this assumption and none has done it on large animals, such as those typically classified as megafauna. We explore this issue in living equids, focusing on ventral cranial variation at both micro- and macro-evolutionary levels. By comparing 2D and 3D data, we found that size is well approximated, whereas shape is more strongly impacted by 2D inaccuracies, as it is especially evident in intra-specific analyses. The 2D approximation improves when shape differences are larger, as in macroevolution, but even at this level precise inter-individual similarity relationships are altered. Despite this, main patterns of sex, species and allometric variation in 2D were the same as in 3D, thus suggesting that 2D may be a source of 'noise' that does not mask the main signal in the data. However, the picture that emerges from this and other recent studies on 2D approximation of 3D structures is complex and any generalization premature. Morphometricians should therefore test the appropriateness of 2D using preliminary investigations in relation to the specific study questions in their own samples. We discuss whether this might be feasible using a reduced landmark configuration and smaller samples, which would save time and money. In an exploratory analysis, we found that in equids results seem robust to sampling, but become less precise and, with fewer landmarks, may slightly overestimate 2D inaccuracies.

Perissodactyla (Rhinocerotidae and Equidae) from Kanapoi.

The Kanapoi collection of Rhinocerotidae, first studied by Hooijer and Patterson (1972), now consists of 25 specimens and substantial reinterpretation of their affinities is made here. Kanapoi post-dates the extinction of Brachypotherium and the whole collection belongs to the Dicerotini. It is important because it includes the type-specimen of Diceros praecox, a species that remains poorly known, but looks slightly larger and more primitive than the modern 'black' rhino, Diceros bicornis. A second species is probably ancestral to the modern 'white' rhino, Ceratotherium simum; it looks identical to the Pleistocene North African Ceratotherium mauritanicum, of which Ceratotherium efficax is probably a synonym. The evolution of the Dicerotini in Africa can be regarded as an increasing divergence in diet and related morphofunctional adaptations in the two lineages. The co-occurrence at Kanapoi of both Diceros and Ceratotherium, with distinct dietary preferences, suggests some habitat heterogeneity, although the low sample size prevents robust paleoecological conclusions. The Equidae are also rare and consist mostly of isolated teeth. I take the most parsimonious option of tentatively including all of them in a single species, whose identification is left open. Dental features of eastern African Pliocene to Pleistocene hipparions may reflect increasing adaptation to grazing.

Neuroaxonal Dystrophy in a mule: first case reported / Distrofia neuroaxonal em muar: primeiro relato de caso

A 12-month-old mule (sterile hybrid equine species) presented unspecific neurological changes (symmetric ataxia, dysmetria, conscious proprioceptive deficit and weakness). Due to poor prognosis and to the fact that a sibling from the previous generation exhibited similar clinical signs that were not definitively diagnosed, the animal was euthanized. Diagnosis of neuroaxonal dystrophy was confirmed by anatomohistopathological analysis. This is the first clinical case of neuronal dystrophy in a mule reported in the world. The clinical and histopathological characteristics of this disease were very similar to those reported for several equine breeds. Therefore, the disease should also be considered in the diagnosis of neurological conditions in mules and donkeys.(AU)

Relata-se o caso de uma mula de 12 meses que apresentou alterações neurológicas inespecíficas (ataxia simétrica, dismetria, déficit proprioceptivo consciente e fraqueza). Devido ao mau prognóstico e ao fato de um irmão da geração anterior apresentar sinais clínicos similares sem diagnóstico conclusivo, o animal foi eutanasiado. O diagnóstico de distrofia neuroaxonal foi confirmado por análise anátomo-histopatológica. Esse é o primeiro caso clínico de distrofia neuroaxonal em muar relatado no mundo. As características clínicas e histopatológicas dessa doença foram muito semelhantes às relatadas em várias raças de equinos. Portanto, a doença também deve ser considerada no diagnóstico de condições neurológicas em muares e asininos.(AU)

Differences in mineral concentrations on hooves of horses, mules and donkeys / Diferenças nas concentrações de minerais nos cascos deequinos, muares e asininos

This study aimed to measure the concentrations of minerals in different regions and pigmentation of horses’ hooves, mules and donkeys. A total of 20 Crioulo horses, 20 mules and 20 Pega donkeys were used. They formed two groups: pigmented (dark) or non-pigmented (bright) hooves. All animals were unshod and with adequate foot conformation. Females were nonpregnant and without foal and no animals were in training. Samples were collected from the hooves of all limbs in the regions of wall, sole and frog. The concentrations of calcium, magnesium, copper, iron and zinc were determined by atomic absorption spectrophotometry; sodium and potassium concentrations were determined by atomic emission spectrophotometry. Among the groups it was observed that the wall, sole and frog of donkeys’ hooves presented higher concentrations of sodium and calcium and with the exception of the frog that also obtained higher levels of copper in this species. Mules had lower concentrations of zinc in the wall and the horses had higher concentrations of potassium and zinc in the sole and higher magnesium in the frog and wall. There was no difference (P>0.05) in concentrations regarding the pigmentation of the hooves. The different regions of the hooves in each group presented similar concentrations of minerals and it was regardless of the pigmentation. The mineral concentrations may be related to desirable functional properties of the donkeys’ hooves. Pigmented and non-pigmented hooves have similar concentrations of minerals.

O objetivo desse trabalho foi mensurar os teores de minerais nas diferentes regiões e pigmentações dos cascos de equinos, muares e asininos. Utilizaram-se 20 equinos da raça Crioula, 20 muares e 20 asininos da raça Pêga. Formaram-se dois grupos conforme os cascos pigmentados (escuros) e não pigmentados (claros). Todos os animais estavam desferrados e com adequada conformação podal e as fêmeas estavam não gestantes e sem potro ao pé e nenhum animal estava em treinamento. Amostras foram coletadas dos cascos de todos os membros nas regiões de parede, sola e ranilha. As concentrações de cálcio, magnésio, cobre, ferro e zinco foram determinadas por espectrofotometria de absorção atômica e as concentrações de sódio e potássio foram determinadas por espectrofotometria de emissão atômica. Entre os grupos observou-se que a parede, sola e ranilha nos asininos apresentaram maiores valores de sódio e cálcio e, exceto para a ranilha, também obteve-se maiores teores de cobre nesta espécie. Os muares apresentaram menores teores de zinco na parede e, os equinos, maiores teores de potássio e zinco na sola e ranilha e de magnésio na ranilha e parede. Não houve diferença (P>0,05) nos teores dos minerais quanto à pigmentação dos cascos. As diferentes regiões dos cascos em cada grupo apresentaram teores similares de minerais e este independeu da pigmentação. As variações dos teores de minerais entre os grupos podem estar relacionados a propriedades funcionais desejáveis dos cascos dos asininos. Cascos pigmentados e não pigmentados apresentam teores similares dos minerais.

Differences in mineral concentrations on hooves of horses, mules and donkeys / Diferenças nas concentrações de minerais nos cascos de equinos, muares e asininos

This study aimed to measure the concentrations of minerals in different regions and pigmentation of horses' hooves, mules and donkeys. A total of 20 Crioulo horses, 20 mules and 20 Pega donkeys were used. They formed two groups: pigmented (dark) or non-pigmented (bright) hooves. All animals were unshod and with adequate foot conformation. Females were non-pregnant and without foal and no animals were in training. Samples were collected from the hooves of all limbs in the regions of wall, sole and frog. The concentrations of calcium, magnesium, copper, iron and zinc were determined by atomic absorption spectrophotometry; sodium and potassium concentrations were determined by atomic emission spectrophotometry. Among the groups it was observed that the wall, sole and frog of donkeys' hooves presented higher concentrations of sodium and calcium and with the exception of the frog that also obtained higher levels of copper in this species. Mules had lower concentrations of zinc in the wall and the horses had higher concentrations of potassium and zinc in the sole and higher magnesium in the frog and wall. There was no difference (P>0.05) in concentrations regarding the pigmentation of the hooves. The different regions of the hooves in each group presented similar concentrations of minerals and it was regardless of the pigmentation. The mineral concentrations may be related to desirable functional properties of the donkeys' hooves. Pigmented and non-pigmented hooves have similar concentrations of minerals.

O objetivo desse trabalho foi mensurar os teores de minerais nas diferentes regiões e pigmentações dos cascos de equinos, muares e asininos. Utilizaram-se 20 equinos da raça Crioula, 20 muares e 20 asininos da raça Pêga. Formaram-se dois grupos conforme os cascos pigmentados (escuros) e não pigmentados (claros). Todos os animais estavam desferrados e com adequada conformação podal e as fêmeas estavam não gestantes e sem potro ao pé e nenhum animal estava em treinamento. Amostras foram coletadas dos cascos de todos os membros nas regiões de parede, sola e ranilha. As concentrações de cálcio, magnésio, cobre, ferro e zinco foram determinadas por espectrofotometria de absorção atômica e as concentrações de sódio e potássio foram determinadas por espectrofotometria de emissão atômica. Entre os grupos observou-se que a parede, sola e ranilha nos asininos apresentaram maiores valores de sódio e cálcio e, exceto para a ranilha, também obteve-se maiores teores de cobre nesta espécie. Os muares apresentaram menores teores de zinco na parede e, os equinos, maiores teores de potássio e zinco na sola e ranilha e de magnésio na ranilha e parede. Não houve diferença (P>0,05) nos teores dos minerais quanto à pigmentação dos cascos. As diferentes regiões dos cascos em cada grupo apresentaram teores similares de minerais e este independeu da pigmentação. As variações dos teores de minerais entre os grupos podem estar relacionados a propriedades funcionais desejáveis dos cascos dos asininos. Cascos pigmentados e não pigmentados apresentam teores similares dos minerais.

The Evolution of a Single Toe in Horses: Causes, Consequences, and the Way Forward.

Horses are a classic example of macroevolution in three major traits-large body size, tall-crowned teeth (hypsodonty), and a single toe (monodactyly)-but how and why monodactyly evolved is still poorly understood. Existing hypotheses usually connect digit reduction in horses to the spread and eventual dominance of open-habitat grasslands, which took over from forests during the Cenozoic; digit reduction has been argued to be an adaptation for speed, locomotor economy, stability, and/or increased body size. In this review, we assess the evidence for these (not necessarily mutually exclusive) hypotheses from a variety of related fields, including paleoecology, phylogenetic comparative methods, and biomechanics. Convergent evolution of digit reduction, including in litopterns and artiodactyls, is also considered. We find it unlikely that a single evolutionary driver was responsible for the evolution of monodactyly, because changes in body size, foot posture, habitat, and substrate are frequently found to influence one another (and to connect to broader potential drivers, such as changing climate). We conclude with suggestions for future research to help untangle the complex dynamics of this remarkable morphological change in extinct horses. A path forward should combine regional paleoecology studies, quantitative biomechanical work, and make use of convergence and modern analogs to estimate the relative contributions of potential evolutionary drivers for digit reduction.

Grayscale histogram analysis to study the echogenicity and echotexture of the walls of the common carotid arteries of horses and mules / Análise por histograma em escala de cinza para estudo da ecogenicidade e ecotextura das paredes das artérias carótidas comuns de equinos e muares

Visual inspection of ultrasound examination for assessment of echogenicity and echotexture of blood vessel tissues is a technique routinely used in medical practice in humans. However, simple visual inspection can lead to poor quality diagnoses and errors. The use of grayscale histogram (GSH) analysis has proved to be an efficient technique to quantify the region of interest, allowing minimization of image interpretation errors. This study aimed to evaluate and compare the echogenicity and echotexture of the walls of the common carotid arteries of healthy female horses and mules using the GSH technique and correlate them with age, body mass, and vessel diameters. B-mode ultrasound examinations were performed in the left and right common carotid arteries in three regions (cranial, middle, and caudal) in 11 horses and 11 healthy mules. The GSH of the animals showed heterogeneous walls, but did not differentiate statistically between female horses and mules. The Mean variable of the middle right, middle left and caudal right sides showed differences, more significant in the mules. On the middle right side, the Min variable was different, higher in the mules. On the middle and caudal left side, the variables Max and Mode showed higher values in the mules. For the mules, the age factor presented negative correlation with the Mean, Mode,, Mode(Count), and Mode(Count)/Count(%) variables, and the body mass factor presented negative correlation with the Mode, Mean and Max variables. For the female horses, the body mass factor showed positive correlation with the Mean and Mode variables. Echogenicity of the carotid artery walls differed between female horses and mules, whereas echotexture was heterogeneous and statistically similar among the animals. The age and body mass factors inversely influenced the echogenicity of the mules, but were not significant in the female horses, in which only the body mass factor positively influenced echogenicity.(AU)

A técnica de avaliação da ecogenicidade e ecotextura dos tecidos dos vasos sanguíneos por inspeção visual do exame de ultrassonografia, já é uma prática da rotina médica em humanos. No entanto, a simples visualização manual pode induzir à erros e diagnósticos de pouca qualidade. O uso de análise por histograma em escala de cinza (HEC) tem se demostrado uma eficiente técnica para quantificar a região avaliada, permitindo minimizar erros de interpretação. O objetivo deste trabalho foi avaliar e comparar a ecogenicidade e ecotextura das paredes das artérias carótidas comuns das fêmeas equina e muares hígidos usando a técnica de HEC, e correlacioná-las com a idade, massa corpórea e diâmetros dos vasos. Exames de ultrassonografia modo-B foram realizados nas artérias carótidas comuns esquerda e direita em três regiões (cranial, médio e caudal) em 11 fêmeas equina e 11 muares hígidos. O HEC dos animais apresentou paredes heterogêneas, mas não diferenciaram estatisticamente entre fêmeas equinas e muares. A variável Mean do lado direito médio, esquerdo médio e caudal apresentou diferenças, sendo maiores nos muares. No lado direito médio, o Min foi diferente, sendo superior nos muares. Já para o lado esquerdo médio e caudal, as variáveis Max e Mode apresentaram valores maiores nos muares. Para os muares, o fator idade apresentou correlação negativa com Mean, Mode, Mode (Count) e Mode(Count)/Count (%) e o fator massa corpórea apresentou correlação negativa com Mode, Mean e Max. Para as fêmeas equinas o fator massa corpórea apresentou correlação positiva com Mean e Mode. A ecogenicidade das paredes das artérias carótidas diferiram entre fêmeas equina e muares, já a ecotextura foi heterogênea e semelhante estatisticamente entre os animais. A idade e a massa corpórea influenciaram inversamente na ecogenicidade dos muares, enquanto que nas fêmeas equina a idade não foi significativa, apenas a massa corpórea influenciou positivamente com a ecogenicidade.(AU)

B-mode and Doppler ultrasonography in the assessment of the common carotid arteries of equines and mules and the relation with body mass, age and neck circumference / Estudo de ultrassonografia modo-B e Doppler na avaliação das artérias carótidas comuns de equinos e muares e a relação com o peso, idade e a circunferência do pescoço

As age increases, changes in cardiovascular anatomy and physiology occur, even in the absence of disease. Thus, studies of vessel hemodynamics are considered primordial to detect any cardiovascular changes. The objective of this study has been to describe the parameters of B-mode and spectral Doppler ultrasonography in the evaluation of the common carotid arteries of 11 equine and 11 mules, and correlate with age, body mass and neck circumferences. The diameters, intima - media thickness (IMT), resistivity index (RI), pulsatility index (PI), systolic velocity (SV), diastolic velocity (DV), maximum velocity (MV), vascular flow index (VFI), body mass, age, circumference and neck length. Ultrasonographic variables were evaluated in three different region called cranial, middle and caudal. Equine females presented higher values regarding the body mass, age and neck length, as compared to the neck circumferences of the animals, those of the mules were superior. The age of the mules had a positive correlation with the body mass, diameter and neck circumferences, it has a negative correlation between age and vessel diameters. The body mass of the mules had a positive correlation with age and vessel diameters, and with vessel diameters and neck circumferences in equine females. The RI and PI variables had a positive correlation with body mass for mules, and with age for equine females. The DV had a negative correlation with body mass for both equine and mule females. Regarding the variables MV and VFI, age correlated negatively for mules, while it was not significant for equine females. It found a difference between equine females and mules in the correlations performed, with body mass, age, neck circumferences and between B-mode and Doppler ultrasonography variables.(AU)

Com o aumento da idade ocorrem alterações na anatomia e fisiologia cardiovascular, mesmo na ausência de doenças. Assim, os estudos da hemodinâmica dos vasos são considerados primordiais para detectar quaisquer alterações cardiovasculares. Esse trabalho tem como objetivo descrever as variáveis de ultrassonografia modo-B e Doppler espectral na avaliação das artérias carótidas comuns de 11 fêmeas equinas e 11 muares, e correlacionar com idade, massa corpórea e circunferências dos pescoços. Para tais procedimentos foram avaliados os diâmetros, espessura da camada íntima média (EIM), índice de resistividade (IR), índice de pulsatilidade (IP), velocidade sistólica (VS), velocidade diastólica (VD), velocidade máxima (VM), índice de vascularização de fluxo (IVF), massa corpórea, idade, circunferências e comprimentos dos pescoços. As variáveis ultrassonográficas foram avaliadas em três regiões diferentes denominados de crania médio e caudal. As fêmeas equinas apresentaram valores maiores referente ao massa corpórea, idade e comprimento dos pescoços, já em relação às circunferências dos pescoços dos animais, as dos muares foram superiores. A idade dos muares possuiu correlação positiva com a massa corpórea, diâmetro e com as circunferências dos pescoços, com as fêmeas equinas, possui correlação negativa entre idade e os diâmetros dos vasos. A massa corpórea dos muares teve correlação positiva com idade e diâmetros dos vasos, já às fêmeas equinas com diâmetros dos vasos e as circunferências dos pescoços. As variáveis IR e IP tiveram correlação positiva com a massa corpórea para os muares, e com idade para fêmeas equinas. O VD teve correlação negativa com a massa corpórea tanto para as fêmeas equinas quanto nos muares. Já as variáveis VM e IVF, a idade correlacionou negativamente para os muares, enquanto não foi significativo para as fêmeas equinas. Averiguou diferença entre fêmeas equinas e muares nas correlações realizadas, com a massa corpórea, idade, circunferências dos pescoços e entre as variáveis da ultrassonografia modo-B e Doppler.(AU)

Elongation of the CA1 field of the septal hippocampus in ungulates.

It is widely assumed that the hippocampal formation seen in laboratory rodents and in primates is typical of that seen in other mammals. We have tested this assumption by examining sections of brains of 56 mammals from 20 mammalian orders from images on the brainmuseum.org website. We found wide variation in the form of the hippocampal formation, the most extreme examples of which are seen in ungulates, which possess an unusual elongation of the distal CA1 of the septal hippocampus. This phenomenon has not previously been reported. In individual coronal sections of the brains of seven artiodactyl ungulates, the pyramidal layer of CA1 is four times as long as CA2 + CA3. In a perissodactyl ungulate (Burchell's zebra) the distal end of CA1 is so large that it forms a number of folds. A similar but less pronounced CA1 elongation was seen in the brains of 14 carnivores. A modest elongation of CA1 is also present in some other placental mammals, notably the elephant shrew, hyrax, capybara, beaver, and rabbit. The elongation was not present in brains of primates, marsupials, or monotremes. The distal part of CA1 has been shown to play a role in object integration into the spatial map. We hypothesize that the distal CA1 enlargement could serve to enhance the ability to integrate objects into spatial navigation, which would be an advantage for migrating herds of ungulates. We suggest that the remarkable elongation of Q5 CA1 represents a major evolutionary specialization in the ungulates.

Bone histology provides insights into the life history mechanisms underlying dwarfing in hipparionins.

Size shifts may be a by-product of alterations in life history traits driven by natural selection. Although this approach has been proposed for islands, it has not yet been explored in continental faunas. The trends towards size decrease experienced by some hipparionins constitute a good case study for the application of a life history framework to understand the size shifts on the continent. Here, we analysed bone microstructure to reconstruct the growth of some different-sized hipparionins from Greece and Spain. The two dwarfed lineages studied show different growth strategies. The Greek hipparions ceased growth early at a small size thus advancing maturity, whilst the slower-growing Spanish hipparion matured later at a small size. Based on predictive life history models, we suggest that high adult mortality was the likely selective force behind early maturity and associated size decrease in the Greek lineage. Conversely, we infer that resource limitation accompanied by high juvenile mortality triggered decrease in growth rate and a relative late maturity in the Spanish lineage. Our results provide evidence that different selective pressures can precipitate different changes in life history that lead to similar size shifts.