Coronary anatomy in neotropical carnivores: A comparative analysis.

This study aims to investigate the anatomy of coronary arteries and their primary branches in neotropical carnivores, given the functional significance of coronary circulation and the limited existing descriptions in this order. For this purpose, coronary arteries were dissected, and their branches were counted in 74 hearts from 20 species belonging to five families: Canidae, Mustelidae, Procyonidae, Mephitidae, and Felidae. In all specimens of the suborder Caniformia, the subsinuosal interventricular branch originated at the end of the circumflex branch of the left coronary artery (LCA). In contrast, in all hearts of Felidae specimens, the subsinuosal branch was derived from the right coronary artery. Among the 50 neotropical specimens of the suborder Caniformia, 13.1 ± 5.2 ventricular branches originated from the LCA and only 4.6 ± 1.4 from the right (p < 0.0001), characterizing a consistent left dominance. However, in the 24 specimens of the Felidae family, 10.5 ± 4.0 ventricular branches were found originating from the LCA and 10.4 ± 3.4 from the right, with no difference between the means (p = 0.82), defining a balanced pattern. It is suggested that the type of coronary circulation may correlate with the phylogeny of carnivorans.

Origin and main ramifications of coeliac artery in Cerdocyon thous.

BACKGROUND: Cerdocyon thous is the canid with the greatest geographical coverage in South America. The aim of this study was to describe the origin, skeletopy, length and main branches of the coeliac artery in C. thous. MATERIALS AND METHODS: The dissections were performed on 14 cadavers of adult specimens, 6 males and 8 females, with a rostrosacral length average of 67.00 ± 4.7 cm and 62.09 ± 5.7 cm, respectively. The specimens were collected dead on highways on the banks of the Atlantic Forest (Rio de Janeiro) and the Pampa biome (Rio Grande do Sul) in Brazil. The cadavers were fixed and preserved in a formaldehyde solution until dissection. The coeliac artery was dissected, the length was measured "in situ" and its main branches were recorded. The coeliac artery emerged as a single artery in all dissected animals. RESULTS: The average length of the coeliac artery was 1.43 ± 0.17 cm in males and 1.39 mm ± 0.24 cm in females, with no significant difference in this measurement between sexes. The predominant skeletopy was at the level of the second lumbar vertebra (57.1%), positioned on average 1.43 cm cranially to the cranial mesenteric artery. In most individuals (92.9%), the classic trifurcation was formed: the coeliac artery branched into the hepatic, left gastric, and lienal arteries. Only 1 male animal presented a bifurcation formed between the hepatic artery and a gastrolienal trunk. CONCLUSIONS: These anatomical characteristics are similar to those of other species of the Canidae family, possibly due to their phylogenetic proximity.

Clavicle in Carnivorans: A Forgotten Bone.

The clavicle is a bone whose development is related to the versatility of the thoracic limbs in mammals. Studies with vestigial structures are scarce and controversial, especially in the order Carnivora. The objective of this study was to verify the presence and to investigate the shape and constitution of the clavicle in neotropical carnivores. In order to do this, 108 cadavers of 19 different species were collected dead on highways and were analyzed. The clavicles were submitted to dissections, longitudinal length measurements, radiographs, histological sections and, in some cases, diaphanization. Sixteen of the 19 species had clavicles in both sides, being significantly larger (P < 0.05) and distinctly more radiopaque in the felids than in the other families. There were no macro or microscopic evidence of clavicle in the specimens of Nasua nasua (n = 6), Conepatus semistriatus (n = 2), and Conepatus chinga (n = 1). The clavicle of the males of Lycalopex gymnocercus, Galictis cuja, and Leopardus geoffroyi was significantly larger (P < 0.05). The predominating contour of the clavicles was a thin stick with cranial convexity. The histological sections demonstrated compact bone consisting of trabecula and lamellae filled by bone marrow and different levels of occupation by chondroid matrix. It can be proposed the clavicles of the order Carnivora, although vestigial and rarely absent, have their presence, constitution and shape more associated with the phylogenetic proximity and evolutionary history of the species than to the variety of movements the thoracic limbs perform in free-living conditions. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1831-1841, 2020. © 2019 American Association for Anatomy.

Functional myology of the thoracic limb in Pampas fox (Lycalopex gymnocercus): a descriptive and comparative analysis.

The characteristics of the muscles of the thoracic limb were evaluated in 22 specimens of Lycalopex gymnocercus. Descriptive and comparative analyses showed similarity with other canids in terms of topography and tendon insertions. Differences with the domestic dog were observed in the pectoralis profundus, triceps brachii and interflexorii muscles. Intraspecific variations were observed in the rhomboideus capitis, serratus ventralis cervicis, extensor carpi radialis, extensor digiti I and II, lumbricales, flexor digiti I brevis, abductor digiti I brevis, and flexor digiti V muscles. The analyses of muscle architecture carried out in nine specimens showed that there was no difference in muscle percentage mass in the thoracic limb of males and females, but a young specimen showed significant lower percentage mass. The triceps brachii caput longus muscle showed the greatest mass, the subscapularis muscle showed the greatest physiological cross-sectional area value, and the extrinsic muscles, in general, presented the longest fascicles and higher architectural indexes. Muscle architecture data were compatible with those of a thoracic limb adapted to fast cursorial locomotion that prioritizes movements in a sagittal plane instead of rotation or adduction/abduction. There was a high association between functional percentage mass of the muscles in the thoracic limb and phylogeny in the Carnivora order. It may be inferred that carnivoran muscle mass is largely determined by phylogeny.

Osteologia do membro torácico de Lycalopex gymnocercus Fischer, 1814 (Carnivora, Mammalia): abordagens comparada, radiográfica e osteométrica / Osteology of the thoracic limb in the Lycalopex gymnocercus Fischer, 1814 (Carnivora, Mammalia): comparative, radiograpahic and osteometric approaches

O membro torácico é a parte do esqueleto pós-craniano que mais informações oferece sobre a locomoção e hábitos de vida de uma espécie. Objetivou-se realizar uma descrição macroscópica, comparativa, radiográfica e osteométrica do esqueleto do membro torácico de Lycalopex gymnocercus. Para tal foram analisados ossos de 24 espécimes adultos coletados mortos em rodovias. Foram realizadas descrições macroscópicas e comparadas com as de outros canídeos, imagens radiográficas para reconhecimento dos padrões de trabeculação e topografia óssea, mensurações lineares e tridimensionais e avaliações histológicas das clavículas. O esqueleto do membro torácico de L. gymnocercus apresentou adaptações morfofuncionais em todos os segmentos para a locomoção cursorial especializada e alguma capacidade de pronação e supinação para captura de presas de porte menor. Houve uma tendência de os ossos serem maiores nos machos, especialmente na região distal do úmero, presumivelmente para a fixação de músculos antebraquiais mais fortes. A clavícula vestigial foi encontrada em todos os espécimes, teve natureza predominantemente cartilagínea e foi significativamente maior nos machos. A conformação básica do esqueleto do membro torácico foi semelhante à dos canídeos domésticos e silvestres descritos na literatura, ainda que particularidades de L. gymnocercus sejam encontradas.(AU)

The forelimb is the part of the post-cranial skeleton that provides more information about locomotion and life habits of a species. The objective of this study was to perform a detailed macroscopic, comparative, radiographic and osteometric investigation of the thoracic limb of Lycalopex gymnocercus. Twenty-four adult specimens collected dead from roadkill were studied. Analysis included macroscopic and comparative descriptions to other canids, radiographic images for recognition of trabeculation patterns and topographical arrangement of bones, linear and three-dimensional measurements, and histological evaluation of the clavicles. The forelimb skeleton of L. gymnocercus presented morphological and functional adaptations in every segment for a specialized cursorial locomotion and some ability to pronation and supination for capture of small vertebrates. There was a tendency for the bones to be longer in males, especially in the distal end of humerus, presumably to fixation of stronger antebrachial muscles. The vestigial clavicle bone was found in all the specimens, had a predominantly cartilaginous nature and was significantly larger in males. The basic conformation of the forelimb skeleton was similar to that of domestic and wild canids described in the literature, although peculiar characteristics of L. gymnocercus have been found.(AU)

Osteologia do membro torácico de Lycalopex gymnocercus Fischer, 1814 (Carnivora, Mammalia): abordagens comparada, radiográfica e osteométrica / Osteology of the thoracic limb in the Lycalopex gymnocercus Fischer, 1814 (Carnivora, Mammalia): comparative, radiograpahic and osteometric approaches

O membro torácico é a parte do esqueleto pós-craniano que mais informações oferece sobre a locomoção e hábitos de vida de uma espécie. Objetivou-se realizar uma descrição macroscópica, comparativa, radiográfica e osteométrica do esqueleto do membro torácico de Lycalopex gymnocercus. Para tal foram analisados ossos de 24 espécimes adultos coletados mortos em rodovias. Foram realizadas descrições macroscópicas e comparadas com as de outros canídeos, imagens radiográficas para reconhecimento dos padrões de trabeculação e topografia óssea, mensurações lineares e tridimensionais e avaliações histológicas das clavículas. O esqueleto do membro torácico de L. gymnocercus apresentou adaptações morfofuncionais em todos os segmentos para a locomoção cursorial especializada e alguma capacidade de pronação e supinação para captura de presas de porte menor. Houve uma tendência de os ossos serem maiores nos machos, especialmente na região distal do úmero, presumivelmente para a fixação de músculos antebraquiais mais fortes. A clavícula vestigial foi encontrada em todos os espécimes, teve natureza predominantemente cartilagínea e foi significativamente maior nos machos. A conformação básica do esqueleto do membro torácico foi semelhante à dos canídeos domésticos e silvestres descritos na literatura, ainda que particularidades de L. gymnocercus sejam encontradas.(AU)

The forelimb is the part of the post-cranial skeleton that provides more information about locomotion and life habits of a species. The objective of this study was to perform a detailed macroscopic, comparative, radiographic and osteometric investigation of the thoracic limb of Lycalopex gymnocercus. Twenty-four adult specimens collected dead from roadkill were studied. Analysis included macroscopic and comparative descriptions to other canids, radiographic images for recognition of trabeculation patterns and topographical arrangement of bones, linear and three-dimensional measurements, and histological evaluation of the clavicles. The forelimb skeleton of L. gymnocercus presented morphological and functional adaptations in every segment for a specialized cursorial locomotion and some ability to pronation and supination for capture of small vertebrates. There was a tendency for the bones to be longer in males, especially in the distal end of humerus, presumably to fixation of stronger antebrachial muscles. The vestigial clavicle bone was found in all the specimens, had a predominantly cartilaginous nature and was significantly larger in males. The basic conformation of the forelimb skeleton was similar to that of domestic and wild canids described in the literature, although peculiar characteristics of L. gymnocercus have been found.(AU)

Osteologia do membro torácico de Lycalopex gymnocercus Fischer, 1814 (Carnivora, Mammalia): abordagens comparada, radiográfica e osteométrica

ABSTRACT: The forelimb is the part of the post-cranial skeleton that provides more information about locomotion and life habits of a species. The objective of this study was to perform a detailed macroscopic, comparative, radiographic and osteometric investigation of the thoracic limb of Lycalopex gymnocercus. Twenty-four adult specimens collected dead from roadkill were studied. Analysis included macroscopic and comparative descriptions to other canids, radiographic images for recognition of trabeculation patterns and topographical arrangement of bones, linear and three-dimensional measurements, and histological evaluation of the clavicles. The forelimb skeleton of L. gymnocercus presented morphological and functional adaptations in every segment for a specialized cursorial locomotion and some ability to pronation and supination for capture of small vertebrates. There was a tendency for the bones to be longer in males, especially in the distal end of humerus, presumably to fixation of stronger antebrachial muscles. The vestigial clavicle bone was found in all the specimens, had a predominantly cartilaginous nature and was significantly larger in males. The basic conformation of the forelimb skeleton was similar to that of domestic and wild canids described in the literature, although peculiar characteristics of L. gymnocercus have been found.

RESUMO: O membro torácico é a parte do esqueleto pós-craniano que mais informações oferece sobre a locomoção e hábitos de vida de uma espécie. Objetivou-se realizar uma descrição macroscópica, comparativa, radiográfica e osteométrica do esqueleto do membro torácico de Lycalopex gymnocercus. Para tal foram analisados ossos de 24 espécimes adultos coletados mortos em rodovias. Foram realizadas descrições macroscópicas e comparadas com as de outros canídeos, imagens radiográficas para reconhecimento dos padrões de trabeculação e topografia óssea, mensurações lineares e tridimensionais e avaliações histológicas das clavículas. O esqueleto do membro torácico de L. gymnocercus apresentou adaptações morfofuncionais em todos os segmentos para a locomoção cursorial especializada e alguma capacidade de pronação e supinação para captura de presas de porte menor. Houve uma tendência de os ossos serem maiores nos machos, especialmente na região distal do úmero, presumivelmente para a fixação de músculos antebraquiais mais fortes. A clavícula vestigial foi encontrada em todos os espécimes, teve natureza predominantemente cartilagínea e foi significativamente maior nos machos. A conformação básica do esqueleto do membro torácico foi semelhante à dos canídeos domésticos e silvestres descritos na literatura, ainda que particularidades de L. gymnocercus sejam encontradas.

Brachial Plexus in the Pampas Fox (Lycalopex gymnocercus): a Descriptive and Comparative Analysis.

Twenty thoracic limbs of ten Lycalopex gymnocercus were dissected to describe origin and distribution of the nerves forming brachial plexuses. The brachial plexus resulted from the connections between the ventral branches of the last three cervical nerves (C6, C7, and C8) and first thoracic nerve (T1). These branches connected the suprascapular, subscapular, axillary, musculocutaneous, radial, median and ulnar nerves to the intrinsic musculature and connected the brachiocephalic, thoracodorsal, lateral thoracic, long thoracic, cranial pectoral and caudal pectoral nerves to the extrinsic musculature. The C7 ventral branches contribute most to the formation of the nerves (62.7%), followed by C8 (58.8%), T1 (40.0%) and C6 (24.6%). Of the 260 nerves dissected, 69.2% resulted from a combination of two or three branches, while only 30.8% originated from a single branch. The origin and innervation area of the pampas fox brachial plexus, in comparison with other domestic and wild species, were most similar to the domestic dog and wild canids from the neotropics. The results of this study can serve as a base for comparative morphofunctional analysis involving this species and development of nerve block techniques. Anat Rec, 300:537-548, 2017. © 2016 Wiley Periodicals, Inc.