Resumo

The crab-eating raccoon Procyon cancrivorus (Cuvier, 1798) is a species of the order Carnivora and family Procyonidae with a geographical distribution in Central and South America. Although crab-eating raccoons use scansorial locomotion, they also have aquatic habits, displaying greatly developed skills when handling their food. This species can frequently be found in wildlife care centers due to injuries caused by domestic dogs, humans, and car collisions. Having knowledge of the species' gross anatomy and anatomical bases is imperative to perform the most appropriate medical and surgical procedures. Thus, the objective of this investigation was to analyze the interspecific and intraspecific differences of the craniolateral forearm muscles of Procyon cancrivorus. Gross dissections were performed in four specimens describing the origin, insertion, shape, innervation, and arterial supply of the craniolateral forearm muscles. There is a constant and well development of brachioradialis muscle comparatively to that described in strictly cursorial species; the extensor carpi radialis muscle has two bellies that are fused proximally; the extensor digitorum communis muscle can also extend the tendon to the digit I as an anatomical variant, and the extensor digiti I and II muscle also extends the tendon to digit III. All are innervated by the deep branch of the radial nerve, and their arterial supply is mainly by the radial collateral, cubital transverse, and cranial interosseous arteries. The anatomical characteristics observed in this study complement the previous descriptions for Procyon cancrivorus, and the anatomical variants found in this species can also be in other carnivorans. Thus, the intraspecific anatomical variations of the digital extensor muscles in P. cancrivorus are phylogenetic traits that can occur as a common pattern or as anatomical variants in other species of the order Carnivora.

El mapache cangrejero Procyon cancrivorus (Cuvier, 1798) es una especie del orden Carnivora y familia Procyonidae con distribución geográfica en América Central y del Sur. Esta especie tiene hábitos arbóreos y acuáticos. Tiene una alta frecuencia en los centros de rehabilitación de fauna silvestre debido a las lesiones causadas por perros, humanos y colisiones de automóviles, por esto, tener conocimiento de la anatomía macroscópica de la especie es imprescindible para realizar los procedimientos médicos y quirúrgicos más adecuados. Por lo tanto, el objetivo de esta investigación fue analizar las diferencias inter e intraespecíficas de los músculos cráneo-laterales del antebrazo de Procyon cancrivorus. Se realizaron disecciones macroscópicas en cuatro especímenes donde se describió el origen, inserción, forma, inervación y la irrigación arterial de la musculatura cráneo-lateral del antebrazo. Entre los principales hallazgos se pueden mencionar: el músculo braquiorradial es constante y bien desarrollado comparativamente a lo descrito en especies estrictamente cursoriales; el músculo extensor radial del carpo presenta dos vientres fusionados proximalmente; el músculo extensor común de los dedos también puede formar un tendón al dedo I como una variante anatómica, y el músculo extensor de los dedos I y II también extiende un tendón al dedo III. Todos están inervados por el ramo profundo del nervio radial y su irrigación arterial es principalmente por las arterias colateral radial, transversa cubital e interósea craneal. Las características anatómicas encontradas en este estudio complementan las descripciones anteriores para Procyon cancrivorus, y las variantes anatómicas encontradas en esta especie también pueden encontrarse en otros carnívoros. Así, las variaciones anatómicas intraespecíficas de los músculos extensores digitales en P. cancrivorus son rasgos filogenéticos que se puede presentar en el patrón común o como variante anatómica en otras especies del orden Carnivora.

Resumo

O lobo-guará Chrysocyon brachyurus Illiger, 1815, é o maior canídeo da América do Sul, pesa cerca de 25 kg quando adulto e está ameaçado de extinção. Descrições anatômicas contribuem para a complementação das informações sobre espécies silvestres e para implicações conservacionistas, clínicas e cirúrgicas. Objetivou-se descrever os ossos e os músculos do antebraço e mão do lobo-guará. A preparação das peças foi feita a partir dos métodos usuais de dissecação, em animais preservados em solução de formol a 10%. Os espécimes pertencem ao acervo didático do Laboratório de Ensino e Pesquisa em Animais Silvestres da UFU e são provenientes de indivíduos atropelados. Os ossos descritos foram: rádio, ulna, ossos cárpico acessório, cárpico ulnar e cárpico intermédio; ossos cárpicos I, II, III e IV; ossos metacárpicos I, II, III, IV, V; falanges proximais, falanges médias e falanges distais do primeiro ao quinto dedo. Os músculos observados foram: extensor radial do carpo; pronador redondo; braquiorradial; extensor comum dos dedos; extensor ulnar do carpo; extensor lateral dos dedos; supinador; abdutor longo do dedo I; flexor radial do carpo; flexor profundo dos dedos; flexor superficial dos dedos; flexor ulnar do carpo; pronador quadrado; interflexor; lumbricais; abdutor curto dos dedos I e II e flexor curto do dedo I.

The maned wolf Chrysocyon brachyurus (Illiger, 1815) is the largest canid in South America, weighs about 25 kg as an adult and is threatened of extinction. Anatomical descriptions contribute to the complementation of information on wild species and for conservation, clinical and surgical implications. The purpose of this study was to describe the bones and muscles of the forearm and hand of the maned wolf. The methodology was through the usual dissecting methods in animals preserved in 10% formalin solution. The animals belong to the didactic collection of the Laboratory of Teaching and Research in Wild Animals of the UFU and come from run over. The bones evaluated were: radius, ulna, carpal accessory, carpi ulnar and carpi intermedium; carpal bones I, II, III and IV; metacarpal bones I, II, III, IV, V; proximal phalanges, middle phalanges and distal phalanges from first to fifth finger. The muscles observed were: radial extensor carpal; pronator round; brachioradial; common extensor of fingers; ulnar carpal extensor; lateral extensor of the fingers; supinator; abductor long finger I; flexor carpi radialis; flexor deep fingers; superficial flexor of the fingers; ulnar flexor of the carpus; square pronator; interflexor; lumbrils; short abductor of fingers I and II and short flexor of finger I.

Resumo

The brachioradialis is an important muscle that acts in the external rotation of the forearm (supination). However, its occurrence is controversial and little studied in the order Carnivora. Thus, this study investigates the occurrence and anatomo-functional arrangement of this muscle in wild carnivorans species. Fifty-eight thoracic limbs of specimens from species of Canidae, Procyonidae, Mustelidae and Felidae were dissected. Measurements of the length of the muscle (ML), the length of the forearm (FL), latero-medial width of the muscle (MW) and the lateral-medial diameter of the forearm (FD) were obtained to establish the ratios MW/FD and ML/FL in order to investigate the relative proportion of the muscle in relation to the forearm of each species. The brachioradialis muscle was identified in all species, although it was unilaterally or bilaterally absent in some canid individuals. The ratios demonstrated significant differences in the anatomical proportions among the families, with greater functional importance in the mustelids, procyonids, and felids because of a set of elaborate movements in the thoracic limb of representatives of these families when compared to canids.

Resumo

Among Vespertilionidae species, sexual size dimorphism is very well documented, in which females are larger than males. The differences are mainly in body weight, skull measurements and forearm length. Studies have discussed some hypothesis for this phenomenon. However, very little information is known about sexual size dimorphism in Myotis nigricans (Schinz, 1821) in Brazil. In this sense, the goal of this paper is to present a study of this phenomenon in the species. For this, we present a quantitative analysis of sexual size dimorphism assessed by traditional morphometrics. Ten skull measurements in addition to the forearm length of adult specimens were taken. Results of traditional morphometrics revealed sexual size dimorphism in five skull measurements and in the forearm length. Females were larger than males. These differences can be attributed to natural selection on large female size for increase fecundity. Bat females of the Vespertilionidae family are usually larger than males in order to perform parental care appropriately and to provide a successful reproductive process.

Entre as espécies de Vespertilionidae, o dimorfismo sexual, no qual as fêmeas são maiores que os machos, é bem documentado. As diferenças aparecem principalmente no peso do corpo, nas medidas cranianas e no comprimento do antebraço. Estudos têm discutido algumas hipóteses para este fenômeno. Contudo, poucas são as informações conhecidas sobre dimorfismo sexual de tamanho para a espécie Myotis nigricans (Schinz, 1821) no Brasil. O objetivo deste artigo é apresentar um estudo deste fenômeno na espécie. Para isso, apresentamos uma análise quantitativa do dimorfismo sexual através da morfometria tradicional, no qual 10 medidas cranianas e o comprimento do antebraço foram tomados. Resultados da morfometria tradicional revelaram dimorfismo sexual em cinco das dez medidas cranianas e no comprimento do antebraço. Em todas as medidas, as fêmeas foram maiores que os machos. As diferenças podem ser atribuídas à seleção natural, favorecendo tamanho maior para as fêmeas para aumentar a fecundidade. Fêmeas da família Vespertilionidae são geralmente maiores a fim de desempenhar adequadamente o cuidado parental e prover processo reprodutivo com sucesso.