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.

Evolutionary history or function? Which preponderates in the expression of the muscle mass of the thoracic limb in wild carnivorans?

Thoracic limbs are extremely versatile and exhibit informative characteristics about habits of the Carnivora order in the wild. Despite this relevance, comparative studies with quantitative variables on thoracic limb muscles are still scarce in carnivorans. The aims of this study were to measure the mass of the intrinsic muscles of the thoracic limb of neotropical species of the Carnivora order and to establish comparative conjectures. For this purpose, 39 thoracic limbs of 10 neotropical carnivorans species were dissected. The mass of each muscle was measured on a digital scale, muscles were grouped by function, and the mass average percentage that each functional group of muscles occupied in the thoracic limb was calculated. The data of the present study was added to that available in the literature for 22 other carnivoran species. Three groups of species were considered: Canidae, Musteloidea, and Feliformia. Comparatively, the eight canid species included in this analyses concentrate muscle mass proximally in the thoracic limb to prioritize essential cursoriality. The nine musteloids had more muscle mass in the distal muscles due to the demand for versatility and manual strength, and the 14 Feliformia species exhibited an intermediate trend. The analysis of clusters revealed a great overlap of the percentage distribution of muscle mass with the phylogeny previously established for carnivorans. It could be verified that the distribution of muscle masses meets the demand of the locomotor habits of the species up to a certain level, from which phylogeny begins to limit morphological adaptations.

Os membros torácicos são extremamente versáteis e exibem características informativas sobre os hábitos das espécies da ordem Carnivora em vida livre. A despeito desta relevência, estudos comparativos com variéveis quantitativas dos músculos do membro torácico são escassos em carnívoros. Os objetivos deste estudo foram aferir a massa dos músculos intrínsecos do membro torácico de espécies neotropicais da ordem Carnivora e estabelecer conjecturas comparativas. Para este fim, foram dissecados 39 membros torácicos de dez espécies de carnívoros neotropicais. A massa de cada músculo foi mensurada em uma balança digital, os músculos foram agrupados por função e calculou-se a massa percentual média a que cada grupo funcional de músculos correspondia no membro torácico. Os dados do presente estudo foram analisados conjuntamente às informações disponíveis na literatura para outras 22 espécies da ordem Carnivora. Três grupos de espécies foram considerados: Canidae, Musteloidea e Feliformia. Comparativamente, as oito espécies de canídeos incluídas nesta análise demonstraram concentração de massa muscular mais proximalmente no membro torácico em razão dos hábitos essencialmente cursoriais. As nove espécies da superfamília Musteloidea exibiram mais massa nos músculos distais devido à maior demanda por versatilidade e força manual. As 14 espécies da subordem Feliformia apresentaram um padrão intermediário. A análise de clusters revelou nítida sobreposição entre o percentual de distribuição da massa muscular com a filogenia previamente estabelecida para a ordem Carnivora. Verificou-se que a distribuição da massa dos músculos atende à demanda dos hábitos locomotores das espécies até um certo nível, a partir do qual a filogenia começa a limitar as adaptações morfológicas.

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.

Coronary irrigation in Puma concolor (Carnivora: Felidae) / Irrigación coronaria en Puma concolor (Carnivora: Felidae)

This study described the anatomy of the coronary arteries and their main branches in Puma concolor. The hearts of six individuals of Puma concolor, were analyzed. The A. coronaria sinistra formed the ramus interventricularis paraconalis and the ramus circunflexus. A ramus septal was formed close to the origin of the ramus interventricularis paraconalis and yielded from six to eight ventricular branches. The circumflex branch originated from two to five atrial branches and from three to seven ventricular branches. The right coronary artery formed two to six atrial branches, and four to nine ventricular branches. In half of the individuals, an accessory coronary artery was identified as the first branch of the right coronary artery. In all individuals, the subsinusal interventricular branch originated in the right coronary artery. It could be inferred that coronary circulation in Puma concolor is balanced, as each coronary artery yielded an interventricular branch and there was no significant difference in the total number of branches that originated from each coronary artery. These findings are different from the descriptions of most carnivore species, and may aid a better understanding of the phylogenetic relationships and synapomorphies of carnivore coronary circulation, especially in the Felidae family.

En este estudio se describió la anatomía de las arterias coronarias, y sus principales ramas, en el Puma concolor. Se analizaron los corazones de seis especímenes de Puma concolor. La arteria coronaria izquierda formó la rama interventricular paraconal y la rama circunfleja. Una rama septal se formó cerca del origen de la rama paraconal y otorgó de seis a ocho ramas ventriculares. La rama circunfleja originó de dos a cinco ramas atriales y de tres a siete ramas ventriculares. La arteria coronaria derecha originó de dos a seis ramas atriales y de cuatro a nueve ramas ventriculares. En la mitad de los especímenes, se identificó una arteria coronaria accesoria como la primera rama de la arteria coronaria derecha. En todos los individuos, la rama interventricular subsinusal se originó en la arteria coronaria derecha. Se podría inferir que la circulación coronaria en el Puma concolor es equilibrada, ya que cada arteria coronaria produce una rama interventricular y no hay diferencia significativa en el número total de ramas que se originan de cada arteria coronaria. Estos hallazgos son diferentes de las descripciones de la mayoría de las especies carnívoras y pueden ayudar a una mejor comprensión de las relaciones filogenéticas y de las sinapomorfias de la circulación de los carnívoros, especialmente en la familia Felidae.

Topografia da papila parotídea em Cerdocyon thous (Linnaeus, 1766) e Lycalopex gymnocercus (G. Fisher, 1814)

Objetivou-se determinar o local de desembocadura do ducto excretor da glândula salivar parótida nos canídeos silvestres Cerdocyon thous e Lycalopex gymnocercus e, assim, fornecer subsídios para procedimentos em medicina veterinária e estudos de anatomia comparada. Para tal, foram inspecionadas as papilas parotídeas de 28 cadáveres (56 hemiarcadas) recolhidos mortos em rodovias: C. thous (cinco machos e nove fêmeas) e L. gymnocercus (nove machos e cinco fêmeas). A partir da papila parotídea traçou-se uma linha imaginária vertical para determinar sua correspondência topográfica em relação aos dentes pré-molares (P) e molares (M). Dois cadáveres de cada espécie foram dissecados para determinação macroscópica da posição da glândula parótida e respectivo ducto. A glândula localizou-se ventralmente à cartilagem auricular e seu ducto apresentou trajeto sobre a face lateral do m. masseter, abrindo-se no vestíbulo oral. Quando consideradas as hemiarcadas, no C. thous houve predominância da abertura do ducto no nível entre P4 e M1 (53,6% dos casos), seguida pela abertura oposta a M1 (46,4%). Os machos de C. thous apresentaram local de desembocadura do ducto em nível significativamente (p-valor = 0,0006) mais caudal do que as fêmeas. No L. gymnocercus em metade das hemiarcadas a abertura ocorreu entre P4 e M1 e na outra metade opostamente a M1, não havendo diferença significativa entre se