Craniolateral forearm muscles of the crab-eating raccoon (Procyon cancrivorus) and a comparative review with other carnivorans

Músculos cráneo-laterales del antebrazo del mapache cangrejero (Procyon cancrivorus) y una revisión comparativa con otros carnívoros

ABSTRACT

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.

KEYWORDS:
Function; innervation; insertion; myology; origin

RESUMEN. 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.

PALABRAS CLAVE:
Función; inervación; inserción; miología; origen

Procyon cancrivorus (Cuvier, 1798) is commonly known as the crab-eating raccoon and it has a wide geographic distribution that ranges from Costa Rica to Uruguay (Cubas et al., 2006; Wilson & Mittermeier, 2009). It belongs to the order Carnivora, suborder Caniformia and family Procyonidae (Nyakatura & Bininda-Emonds, 2012). Phenotypically, P. cancrivorus is a medium-sized animal (2-6 kg, Labate et al., 2001), with a wide tail which is approximately 50% of its total body length and is marked by five to ten dark and yellowish rings (Cubas et al., 2006). One of the main facial characteristics of the species is a dark mask around the eyes (Labate et al., 2001). The species also portrays elongated limbs including hands without hair (Nowak, 1999; Cubas et al., 2006). Within the family Procyonidae, the species of the genus Procyon are semipalmigrades with five functional digits in its hands, providing skills to climb and handle food (Mcclearn, 1992).

It is a solitary species, with nocturnal and twilight habits that lives in shrubby areas close to rivers, swamps, or similar sources of water (Nowak, 1999; Pellanda et al., 2010). This is possibly due to its diet consisting of crab, and its ability to swim (Cubas et al., 2006; Martinelli & Volpi, 2010). Although P. cancrivorus is a species with few studies due to its nocturnal and crepuscular habits, it frequents the terrestrial substratum, and climb trees in search of refuge (Massoia et al., 2012). Therefore, this species characterizes its locomotion for being mainly terrestrial (Wilson & Mittermeier, 2009; Massoia et al., 2012), but also having arboreal and swimming abilities (Indrusiak & Eizirik, 2003; Martinelli & Volpi, 2010; Pellanda et al., 2010). This can lead to changes in the shape and arrangement of the muscles (Diogo & Abdala, 2010), such as has been reported in the flexor digitorum superficialis and palmaris longus muscles in carnivorans (Perdomo-Cárdenas et al., 2021). For example, some mustelids and species of the genera Procyon, Nasua, Ailurus and Ailuropoda have one m. palmaris longus evolutionarily derived from the m. flexor digitorum superficialis (Mackintosh, 1875; Davis, 1964; Mcclearn, 1985; Fisher et al., 2009; Perdomo-Cárdenas et al., 2021). While the genus Potos has developed two palmaris longus muscles, from which it is inferred that it may have occurred due to Potos has higher manual abilities than other carnivoran species (Mcclearn, 1992; Perdomo-Cárdenas et al., 2021). However, the presentation of a m. palmaris longus in carnivorans is also associated to a palmigrade or semipalmigrade locomotion (Perdomo-Cárdenas et al., 2021). On the other side, the rotators muscles are functionally more developed in arboreal carnivorans, while the humeral adductors and scapular adductor and protractors are more developed in terrestrial carnivorans (Taverne et al., 2018). Therefore, possible anatomical variations can also be found in species with different locomotion habits.

The movements of the different types of locomotion are generated by the contraction of the different muscle groups and the functioning of the peripheral nervous system. This innervates the muscles, providing the opportunity for chemical energy to be transformed into mechanical energy, resulting in the production of various movements (Paranaiba et al., 2012). The function of the thoracic limb muscles is fundamental to the animal capturing food, mating, and defending itself. These needs vary according to their habits of life, showing how fundamental is the study of the functional anatomy of different species (Aversi-Ferreira et al., 2005). The thoracic limbs, specifically the craniolateral muscles of the forearm, have functions of supination of the manus, extension of digits, and adduction and abduction of the carpus (Hermanson et al., 2013). Although, there are three studies about the thoracic limb muscles in P. cancrivorus (Windle, 1888; Lima et al., 2010; Santos et al., 2010a), these do not contain a detailed description of the craniolateral forearm muscles. Among these studies, someone did not report the m. brachioradialis (Santos et al., 2010b), the m. supinator (Lima et al., 2010), and the m. extensor digiti I et II (Lima et al., 2010; Santos et al., 2010a,b). The detailed knowledge of these muscles will give an anatomical basis allowing the performance of surgical procedures of the distal part of the humerus, and the entire length of the radius and the ulna. Also, this knowledge would be useful to evolutionary studies, such as muscular reconstructions in fossil procyonids (Tarquini et al., 2019; Vélez-García et al., 2021). Thus, the main objective was to analyze the intra- and interspecific differences of the craniolateral forearm muscles of P. cancrivorus.

MATERIAL AND METHODS

Specimens and fixation process. Four specimens of P. carnivorous (two juvenile females and two adult males) that died of natural causes were used. These specimens remain at the amphitheater of Veterinary Anatomy of the Universidad del Tolima. One male with skin and one female without skin were donated by CORPOCALDAS (Corporación Autónoma Regional de Caldas, environmental authority of Caldas-Colombia) to the Universidad de Caldas; and two necropsied specimens (a juvenile female and an adult male) were donated by CORTOLIMA (Corporación Autónoma Regional del Tolima environmental authority of Tolima-Colombia). The specimens were fixed with intramuscular and subcutaneous infiltrations of a solution of 10% formaldehyde and 20% glycerin, and then submerged in a solution of 5% formaldehyde. In one of the females, arterial repletion was performed with latex dyed with red vinyl through the axillary arteries. This study was approved by the bioethics committee of the Universidad del Tolima (2.3-059).

Dissection and documentation. Gross dissections of both thoracic limbs were performed base on Evans & De Lahunta (2017). The origin, insertion, innervation, and arterial supply of each muscle were described according to the Nomina Anatomica Veterinaria (Icvgan, 2017). Photographic records of dissections were taken with a Canon EOS Rebel T5i 18 MP camera associated with a macro lens of 60 mm and a Canon 6D associated with a macro lens of 100 mm.

RESULTS

The m. brachioradialis was fusiform and flattened, with a fleshy origin from the proximal extreme of the lateral supracondylar crest of the humerus, and it was inserted by a tendon onto the proximal part of the styloid process of the radius (Figs 1, 2 and 4). It was innervated by the deep branch of the radial nerve (Fig. 5 and supplied by the collateral radial and transverse cubital arteries.

Fig. 1.
Cranial view of a left forearm (a), and lateral view of a left forearm (b). 1, m. brachioradialis; 2, m. extensor carpi radialis; 2’, cranial belly; 2”, caudal belly; 3, m. extensor digitorum communis; 3’, tendon; 4, m. extensor digitorum lateralis; 4’, tendon of insertion of the m. extensor digitorum lateralis; 5, m. extensor carpi ulnaris; 5’, tendon 6, m. abductor digiti i longus; 7; retinaculum extensor.

Fig. 2.
Lateral views of a left forearm where the m. extensor digitorum communis had been retracted toward caudal to see the bellies of the m. extensor carpi radialis. 1, m. brachioradialis; 2, m. extensor carpi radialis; 2’, cranial belly; 2”, caudal belly; 3, m. extensor digitorum communis; 3’, tendon; 4, m. extensor digitorum lateralis; 4’, tendon of insertion of the m. extensor digitorum lateralis; 5, m. extensor carpi ulnaris; 6, m. abductor digiti i longus.

The m. extensor carpi radialis (Figs 1-3) had a fleshy origin from the two distal thirds of the medial aspect of the lateral supracondylar crest of the humerus and the proximal fifth of the intermuscular septum with the m. extensor digitorum communis, which covered superficially the origin of the m. extensor carpi radialis. Two muscular bellies (cranial and caudal; Fig. 2) were formed from the proximal third of the forearm, the cranial belly was fusiform, and the caudal belly was bipennate. The cranial belly formed a tendon from the middle third of the forearm, whilst the caudal belly was free of muscle fibers from the distal third of the forearm. Both tendons passed deep to the tendon of the m. abductor digiti I longus. The tendon of the cranial belly inserted onto the dorsal surface of the base of metacarpal bone II, and the caudal belly onto the dorsal surface of the base of metacarpal bone III (Fig. 3). It was innervated by two branches of the deep branch of radial nerve (Fig. 5). Both bellies were supplied by the transverse cubital artery (Fig. 5), and the caudal belly also by a branch of the cranial interosseous artery.

Fig. 3.
Dorsal view of a left hand, dorsal view of a right hand (b), deep dorsal view of a left hand (c). 1, Extensor digitorum communis tendon; 1’, tendon to the digit I; 2, extensor digiti I et II tendons; 2’, medial tendon, 2”, lateral tendon; 3, extensor digitorum lateralis tendons; 3’, medial; 3”, intermediate; 3”’, lateral; 4, extensor carpi radialis tendon; 4’, tendon of the cranial belly; 4”, tendon of the caudal belly; 5, retinaculum extensor.

Fig. 4.
Deep lateral views of a two left forearms (a-b), and deep cranial view of a left forearm (c). 1, m. brachioradialis; 2, m. extensor carpi radialis; 3, m. supinator; 4, m. abductor digiti I longus; 4’, tendon; 5, m. extensor digiti I et II; 5’, medial tendon; 5”, lateral tendon; 6, m. extensor carpi ulnaris.

Fig. 5.
Lateral view of a left forearm where the m. brachioradialis had been retracted toward medial (a), and lateral view of a left forearm (b). 1, m. brachioradialis; 2, m. extensor carpi radialis; 3, m. extensor digitorum communis; 4, m. extensor digitorum lateralis; 5, m. extensor carpi ulnaris; 6, cranial interosseous artery; 7, m. supinator; 8, transverse cubital artery; 1’, 2’, 7’, branches of the deep branch of radial nerve to the respective muscle.

The m. extensor digitorum communis (Figs 1, 2 and 5) originated via fleshy and tendinous fibers from the lateral aspect of the distal third of the lateral supracondylar crest of the humerus, the lateral epicondyle of the humerus, and the adjacent intermuscular septa (m. extensor carpi radialis and m. extensor digitorum lateralis). This muscle formed a deep common tendon with the m. extensor digitorum lateralis, which originated from the lateral epicondyle of the humerus. In two specimens, muscle fibers originating from the antebrachial fascia were observed. In the middle of the forearm, four tendons were formed, but these were only free of fleshy fibers from the distal quarter of the forearm. Each tendon was inserted onto the extensor process of the distal phalanges of the digits II-V (Figs 3). In one thoracic limb of two specimens, the medial tendon sent a fascicle to the digit I (unilaterally), which joined to the medial tendon of the m. extensor digiti I et II. The muscle was innervated by the deep branch of radial nerve and supplied by the cranial interosseous and transverse cubital arteries (Fig. 5).

The m. extensor digitorum lateralis had a fleshy and tendinous origin from the lateral epicondyle of the humerus, intermuscular septum with the m. extensor digitorum communis, antebrachial fascia, and lateral collateral ligament of the elbow. It also had a common deep origin tendon with the m. extensor digitorum communis, which originated from the lateral epicondyle of the humerus (Fig. 1). In one specimen, the origin from the antebrachial fascia was not observed. Distally, the muscle formed three tendons that extended to the digits III-V, which joined the extensor digitorum communis tendons (Fig. 3). It was innervated by the deep branch of the radial nerve and was supplied by the cranial interosseous artery (Figs 1, 5).

The m. extensor carpi ulnaris was fusiform, originated via a tendon from the distal extreme of the lateral epicondyle of the humerus. It formed a flat tendon in the distal third of the forearm (Figs 1, 2), which inserted onto the base of the metacarpal V and the accessory carpal bone (Figs 4, 5). There was a synovial bursa at the level of the cranial surface of the styloid process of the ulna, which protected its tendon. In a left forearm, the muscle presented an ulnar head, which originated from the three middle fifths of the caudal part of the lateral surface of ulna (just caudal to the ulnar origin of the m. abductor digiti I longus) (Fig. 6). It was innervated by the deep branch of the radial nerve and was supplied by the cranial interosseous artery (Fig. 5).

Fig. 6.
Lateral view of a left forearm where the m. extensor carpi ulnaris had been retracted toward cranial. 1, m. extensor carpi ulnaris; 1”, ulnar head (variant accessory head) of the m. extensor carpi ulnaris; 2, M. extensor digiti I et II; 3, M. abductor digiti I longus.

The m. abductor digiti I longus (Figs 1, 2, 4) was bipennate and had a wide fleshy origin from the middle third of the lateral margin of the radius, along the antebrachial interosseous ligament, the antebrachial interosseous membrane, and the lateral surface of the ulna. In two specimens, its origin was also observed from the lateral collateral ligament of the elbow. It inserted by a tendon onto the medial surface of the base of the metacarpal I and the sesamoid bone (Fig. 4). Its tendon passed superficially to the tendons of m. extensor carpi radialis. It was innervated by the deep branch of the radial nerve and was supplied by the cranial and caudal interosseous arteries.

The m. extensor digiti I et II had two bellies, which originated from the caudal part of the lateral surface of the ulna and the epimysium of the m. abductor digiti I longus (Fig. 4). It formed two tendons, one medial and one lateral, the medial tendon extended to the digit I and the abaxial surface of the digit II; and the lateral tendon extended to the axial surface of the digit II and the abaxial surface of digit III. Both tendons joined with the extensor digitorum communis tendons at the level of the metacarpophalangeal joint (Figs 3, 4). It was innervated by the deep branch of the radial nerve and was supplied by the cranial interosseous artery.

The m. supinator was fusiform with a tendinous origin from the lateral epicondyle of the humerus, the annular radial ligament, and the lateral collateral ligament of the elbow. It had a fleshy insertion onto the proximal third of the cranial surface, lateral, and medial margins of the radius (Fig. 4). It was innervated by the deep branch of the radial nerve (Fig. 5) and supplied by the transverse cubital and cranial interosseous arteries.

DISCUSSION

Comparative myology. The m. brachioradialis of the specimens of P. cancrivorus in the current study had the same attachments reported by other authors (Windle, 1888; Lima et al., 2010; Souza-Junior et al., 2015). Although Santos et al. (2010a,b) did not mention the m. brachioradialis, this muscle was present on their figures. Therefore, the brachioradialis is a common muscle in P. cancrivorus as in other procyonids (Mackintosh, 1875; Allen, 1882; Windle & Parsons, 1897; Julitz, 1909; Mcclearn, 1985; Souza-Junior et al., 2015, 2021; Vélez-García et al., 2021), mustelids (Macalister, 1873; Mackintosh, 1875; Windle & Parsons, 1897; Leach, 1976; Moore et al., 2013; Ercoli et al., 2015; Souza-Junior et al., 2015; Böhmer et al., 2020), ailurids (Fisher et al., 2009), ursids (Haughton, 1864; Shepherd, 1883; Kelley, 1888; Windle & Parsons, 1897; Davis, 1964), herpestids (Taylor, 1976), felids (Beswick-Perrin, 1871; Windle & Parsons, 1897; Barone, 1967; Concha et al., 2004; Julik et al., 2012; Cuff et al., 2016; Viranta et al., 2016; Nazem et al., 2017; Vargas et al., 2017; Ari et al., 2019; Sánchez et al., 2019), and viverrids of the genera Genetta (Taylor, 1976) and Paradoxurus (Beswick-Perrin, 1871). Whilst, it is a small or absent muscle in canids (Haughton, 1864; Vaz et al., 2011; Hermanson, 2013; Echeverry et al., 2015; Souza-Junior et al., 2015, 2018; Böhmer et al., 2020; Smith et al., 2020), felids of the genus Acynonix (Windle & Parsons, 1897; Taverne et al., 2018; Böhmer et al., 2020), hyaenids (Watson & Young, 1879; Watson, 1882; Spoor & Badoux, 1986; Böhmer et al., 2020), and viverrids of the genus Civettictis (Devis, 1868; Young, 1880; Macalister, 1873; Windle & Parsons, 1897). In mustelids of the family Ictonychidae and subfamily Lutrinae, the origin is from the proximal third of the humerus (Windle & Parsons, 1897; Howard, 1973; Ercoli et al., 2015; Souza-Junior et al., 2015), while it originates only from the middle third in Galictis cuja (Ercoli et al., 2015), or from the cranial aspect of the lateral epicondyle in Taxidea taxus (Moore et al., 2013). In the ailurid Ailurus fulgens, it has two heads, in which one originates from the lateral supracondylar crest and the other from the m. brachialis (Fisher et al., 2009). In ursids, it can also have two heads similar to Ailurus, such as Ursus maritimus (Kelley, 1888) and Ailuropoda melanoleuca (Davis, 1964), whereas Ursus americanus only has one head from the lateral supracondylar crest (Haughton, 1864; Shepherd, 1883). The origin of the m. brachioradialis in felids reaches the middle third of the humerus (Julik et al., 2012; Concha et al., 2004; Viranta et al., 2016; Vargas et al., 2017; Ari et al., 2019; Dunn et al., 2022), however, it could originate from the proximal third in Panthera and Leopardus (Barone, 1967; Sánchez et al., 2019; Smith et al., 2021) or only from the lateral supracondylar crest in Caracal, Acynonyx and Leopardus (Beswick-Perrin, 1871; Hudson et al., 2011; Souza-Junior et al., 2015). Carnivorans present few variants in the insertion of m. brachioradialis, however, there are some differences, such as in herpestids (Ichneumia albicauda and Herpestes ichneumon), since the m. brachioradialis inserts onto the cranial surface of the distal extreme of the radius (Taylor, 1976); in Ailurus it also inserts onto the m. pronator teres (Fisher et al., 2009); in Leopardus pardalis, Leopardus. geoffroyi and Panthera onca it also inserts onto the proximal row of the carpus (Sánchez et al., 2019) or in Lynx lynx only onto the radial carpal bone (Ari et al., 2019); and in L. pardalis onto the flexor retinaculum (Julik et al., 2012). In the euplerid Cryptoprocta ferox, the muscle was only described as a muscle well developed (Böhmer et al., 2020).

The m. extensor carpi radialis in P. cancrivorus has been described as a single muscle (Lima et al., 2010; Santos et al., 2010a), such as occurs in other procyonid as Nasua nasua (Santos et al., 2010b), some mustelids (Haughton, 1864; Macalister, 1873; Howard, 1973; Leach, 1976; Moore et al., 2013), canids (Haughton, 1864; Vaz et al., 2011; Hermanson, 2013; Echeverry et al., 2015; Souza-Junior et al., 2015, 2018; Smith et al., 2020), hyaenids (Watson & Young, 1879; Watson, 1882; Spoor & Badoux 1986), herpestids (Taylor, 1976), viverrids (Devis, 1868; Macalister, 1873; Young, 1880; Taylor, 1976), and some felids, such as Caracal caracal (Beswick-Perrin, 1871), Acynonyx jubatus (Hudson et al., 2011; Nazem et al., 2017; Böhmer et al., 2020), and L. lynx (Viranta et al., 2016). However, we observed two muscle bellies in the m. extensor carpi radialis of P. cancrivorus, one cranial and one caudal, which corresponded respectively to the m. extensor carpi radialis longus and m. extensor carpi radialis brevis described independently in other procyonids (without fusion), such as Procyon lotor (Allen, 1882; Mcclearn, 1985), N. nasua (Mackintosh, 1875; Mcclearn, 1985; Böhmer et al., 2020), and Potos flavus (Beswick-Perrin, 1871; Julitz, 1909; Böhmer et al., 2020; Vélez-García et al., 2021). Therefore, based on the findings in P. cancrivorus, these muscles were not considered as independent muscles because they had intermixed fleshy fibers between them. Mackintosh (1875) in Nasua narica describes that both muscle bellies are partly fused, similar to our findings in P. cancrivorus. In P. flavus, both muscles can have intermixed fibers as an anatomical variant, but in a very low proportion (Vélez-García et al., 2021). Some mustelids can have both independent muscles, such as Martes foina, Martes martes, Meles meles and a specimen of G. cuja (Ercoli et al., 2015; Böhmer et al., 2018, 2020). Although, both muscle bellies can be partly fused as in M. foina (Mackintosh, 1875), Eira barbara (Macalister, 1873), and Enhydra lutris (Howard, 1973). Ursids such as U. americanus and U. maritimus, present a single muscle (Shepherd, 1883; Kelley, 1888), although it was described as two independent muscles in Ursus sp. (Haughton, 1864) and A. melanoleuca (Davis, 1964). In Ailurus both muscle bellies are only separated on the middle of the forearm, but both can be completely separated as an anatomical variant (Fisher et al., 2009). In felids, it was divided into two muscles (Concha et al., 2004; Icvgan, 2017; Sánchez et al., 2019; Dunn et al., 2022), but both muscle bellies can be fused proximally in Felis catus (Barone, 1980), L. pardalis (Julik et al., 2012), Panthera leo (Barone, 1980; Vargas et al., 2017), Panthera uncia (Smith et al., 2021), Panthera tigris (Dunn et al., 2022), and L. lynx (Ari et al., 2019); even the brevis belly may be fused with the m. extensor digitorum communis in L. pardalis (Julik et al., 2012). Although, in P. leo both muscles were reported independently, similar to that described in the hyaenid Hyena hyaena and the herpestid H. auropunctatus (Böhmer et al., 2020).

The origin of the m. extensor digitorum communis of P. cancrivorus was similar to that observed by Lima et al. (2010), however these authors did not report the origin from the intermuscular septa. Other authors only reported the origin from the lateral epicondyle of the humerus (Santos et al., 2010a), similar to that observed in other procyonids such as N. nasua (Santos et al., 2010b), N. narica (Mackintosh, 1875), and P. flavus (Julitz, 1909; Vélez-García et al., 2021). Although in P. flavus, origins from the adjacent intermuscular septa have also been reported (Vélez-García et al., 2021). Other studies in procyonids reported a restricted origin from the lateral supracondylar crest of the humerus in P. lotor (Allen, 1882; Mcclearn, 1985), N. nasua and N. narica (Mcclearn, 1985). In mustelids, it can originate only from the lateral supracondylar crest (Leach, 1976; Böhmer et al., 2018) or from lateral epicondyle (Mackintosh, 1875; Moore et al., 2013), whereas G. cuja and E. lutris has both origins (Howard, 1973; Ercoli et al, 2015), similar to that observed in P. cancrivorus. In A. fulgens, it only originates from the lateral epicondyle, however, it can originate from the m. extensor carpi radialis brevis or be fused with the m. extensor digitorum lateralis as anatomical variants (Fisher et al., 2009). In Ursus, the m. extensor digitorum communis originates from the lateral epicondyle (Shepherd, 1883; Kelley, 1888), while in Ailuropoda it originates from the lateral supracondylar crest and it is proximally inseparable to the adjacent muscles (Davis, 1964). In canids, it originates from the lateral epicondyle (Vaz et al., 2011; Hermanson, 2013; Souza-Junior et al., 2018; Liebich et al., 2020; Smith et al., 2020), however it also originates from the intermuscular septum with the m. extensor carpi radialis and antebrachial fascia in Canis lupus familiaris (Hermanson et al., 2013) and also from the articular capsule of the elbow in Cerdocyon thous (Echeverry et al., 2015). In most felids, it originates from the lateral epicondyle, while in some species it originates from the lateral supracondylar crest, such as in L. pardalis (Julik et al., 2012), A. jubatus (Hudson et al., 2011; Nazem et al., 2017), P. leo (Barone, 1967; Vargas et al., 2017), P. uncia (Smith et al., 2021), and P. tigris (Dunn et al., 2022). In L. lynx, the muscle can originate from the lateral epicondyle of the humerus (Viranta et al., 2016) and lateral supracondylar crest (Ari et al., 2019), and it also has other origins either from the lateral margin of the radius (Viranta et al., 2016), or from the ulna and olecranon (Ari et al., 2019), which is uncommon in carnivorans. In hyaenids and viverrids it originates from the lateral epicondyle (Devis, 1868; Watson & Young, 1879; Young, 1880; Watson, 1882; Spoor & Badoux 1986). In C. crocuta, it also originates from the intermuscular septum (Watson & Young, 1879), whereas Taylor (1976) observed in the viverrid Genetta and herpestids an origin from the lateral supracondylar crest. The m. extensor digitorum communis extends tendons to the digits II-V in most carnivorans, however it also extends a tendon to the digit I in M. foina (Böhmer et al., 2020), and L. lynx (Viranta et al., 2016). Although in L. lynx that tendon can be absent (Ari et al., 2019), thus the tendon for the digit I is an anatomical variant in this species, being similar to that reported in P. leo (Vargas et al., 2017) and the findings of this study in P. cancrivorus.

The origin of the m. extensor digitorum lateralis in P. cancrivorus has been reported from the lateral ligament of the elbow and the lateral tuberosity of the radius (Lima et al., 2010), or from the lateral epicondyle of the humerus (Santos et al., 2010a). This partially agrees with our findings, since the origin from the radius was not found, and the origins from the intermuscular septum and the antebrachial fascia was not reported by those studies. In P. flavus, the muscle also originates from the lateral collateral ligament of the elbow and intermuscular septum (Vélez-García et al., 2021), similar to P. cancrivorus. In other procyonids, it only originates from the lateral epicondyle (Mackintosh, 1875; Mcclearn, 1985; Santos et al., 2010b) or the lateral supracondylar crest in P. lotor (Allen, 1882). However, the muscle sends tendons to the digits III to V in all procyonids (Mackintosh, 1875; Allen, 1882; Mcclearn, 1985; Lima et al., 2010; Santos et al., 2010a,b; Böhmer et al., 2020; Vélez-García et al., 2021). In N. narica, it can form two muscles, one lateral that only extends to the digit V, and one medial that extends to the digits III and IV (Mackintosh, 1875). This disposition of N. narica can also occur in some mustelids, such as Aonyx (Macalister, 1870), G. cuja (Ercoli et al., 2015), and T. taxus (Moore et al., 2013), whereas one muscle extends tendons to the digits III-V in E. barbara (Macalister, 1873), M. foina and M. meles (Böhmer et al., 2020). In Martes americana and Pekania penannti, it originates from the lateral epicondyle and the lateral proximal side of the radius (Leach et al., 1976); whereas in M. foina and M. martes, it originates from the lateral supracondylar crest and only extends to the digits IV and V (Böhmer et al., 2018). In E. lutris, it originates from the lateral supracondylar crest and lateral epicondyle, and extends tendons to the digits IV and V (Howard, 1973). In A. melanolueca, it originates from the lateral epicondyle and condyle and only extends to the digits IV and V (Davis, 1964), whereas in Ursus, it only originates from the lateral epicondyle and extends to the digits III-V (Haughton, 1864; Shepherd, 1883; Kelley, 1888), being similar to Ailurus (Fisher et al., 2009). In canids, it originates from the lateral epicondyle (Vaz et al., 2011; Echeverry et al., 2015; Souza-Junior et al., 2018; Smith et al., 2020), however, it also originates from the lateral collateral ligament of the elbow in C. l. familiaris (Hermanson, 2013), C. thous (Echeverry et al., 2015), and Lycaon pictus (Smith et al., 2020). Even it also originates from the intermuscular septum with the m. extensor digitorum communis in C. thous (Echeverry et al., 2015). In some canids as Cuon alpinus and Vulpes vulpes, the tendon to the digit III is absent (Böhmer et al., 2020). In felids, it originates from the lateral epicondyle (Beswick-Perrin, 1871; Barone, 1986; Concha et al., 2004; Hudson et al., 2011; Nazem et al., 2017; Viranta et al., 2016; Vargas et al., 2017; Smith et al., 2021; Dunn et al., 2022), or the lateral supracondylar crest (Julik et al., 2012; Sánchez et al., 2019; Liebich et al., 2020), however in L. pardalis it also originates from the m. supinator (Julik et al., 2012). On the other side, the muscle sends tendons to the digits III to V in all felids (Beswick-Perrin, 1871; Barone, 1986; Concha et al., 2004; Hudson et al., 2011; Julik et al., 2012; Nazem et al., 2017; Viranta et al., 2016; Vargas et al., 2017; Ari et al., 2019; Sánchez et al., 2019; Böhmer et al., 2020), although in F. catus, it can also extend a tendon to the digit II (Barone, 1980; Liebich et al., 2020), similar to L. pardalis (Julik et al., 2012) and P. tigris (Dunn et al., 2022). In herpestids, viverrids, and hyaenids, it originates from the lateral epicondyle (Devis, 1868; Watson & Young, 1879; Watson, 1882; Taylor, 1976; Spoor & Badoux, 1986), and extends tendons to the digits IV-V (Devis, 1868; Watson & Young, 1879; Watson, 1882; Spoor & Badoux, 1986; Böhmer et al., 2020). Although, it may also originate from the radius, near the insertion point of the lateral collateral ligament of the elbow in Hyaenae hyaenae (Spoor & Badoux, 1986), and it can also extend a tendon to the digit III in the viverrid Civettictis civetta (Macalister, 1873; Young, 1888), the herpestid Herpestes auropunctatus and the euplerid C. ferox (Böhmer et al., 2020).

The origin and insertion of the m. extensor carpi ulnaris observed in P. cancrivorus agree with other studies (Windle, 1888; Santos et al., 2010a), whereas other authors did not report an insertion onto the accessory carpal bone (Lima et al., 2010). In other procyonids, it can have an origin from the olecranon, such as in N. narica (Mackintosh, 1875) and P. flavus (Julitz, 1909); or from the body of the ulna in P. cancrivorus as an anatomical variant. Even the muscle also originates from the articular capsule of the elbow in P. flavus (Vélez-García et al., 2021). The muscle also inserts onto the accessory carpal bone in P. lotor (Allen, 1882) and P. flavus (Vélez-García et al., 2021), similar to our findings in P. cancrivorus. Although Mcclearn (1985) only reports the insertion onto the metacarpal V in P. lotor and Nasua. The origin and insertion in P. cancrivorus are also similar to mustelids (Macalister, 1870; Howard, 1973; Leach et al., 1976; Moore et al., 2013; Ercoli et al., 2015), ursids (Haughton, 1864; Shepherd, 1883; Kelley, 1888), Ailurus (Fisher et al., 2009), canids (Haughton, 1864; Vaz et al., 2011; Hermanson, 2013; Echeverry et al., 2015; Souza-Junior et al., 2015; Souza-Junior et al., 2018; Smith et al., 2020), felids (Beswick-Perrin, 1871; Barone, 1986; Concha et al., 2004; Hudson et al., 2011; Viranta et al., 2016; Nazem et al., 2017; Vargas et al., 2017), herpestids (Taylor, 1976), and viverrids (Devis, 1868; Watson, 1882; Taylor, 1976). However, there are some differences with some mustelid species, such as in G. cuja, where the m. extensor carpi ulnaris originates from the articular capsule of the elbow (Ercoli et al., 2015). On the other hand, there was no carpal insertion in T. taxus (Moore et al., 2013), M. martes and M. foina (Böhmer et al., 2018). In the ursid A. melanoleuca, it also originates from the condyle and its fibers are inseparable from the anconeus and extensor digitorum lateralis muscles, and it does not insert onto the accessory carpal bone (Davis, 1976). In felids, such as L. pardalis it fuses with the articular capsule of the elbow and m. anconeus, and it does not insert on the accessory carpal bone (Julik et al., 2012). In L. lynx, it can also originate from the ulna and insert onto the extensor retinaculum (Viranta et al., 2016), but does not insert onto the accessory carpal bone (Viranta et al., 2016; Ari et al., 2019). In P. uncia and P. tigris, it does not insert onto the accessory carpal bone (Smith et al., 2021; Dunn et al., 2022), but in P. tigris, it inserts onto the accessory carpal ligament (“pisometacarpal ligament” Dunn et al., 2022). In viverrids of the genus Genetta, it also originates from the ulna (Taylor, 1976). In hyaenids, it does not insert onto the carpus (Watson & Young, 1876; Spoor & Badoux, 1986), although in Proteles inserts onto the retinaculum extensor (Watson, 1882).

The radial and ulnar origins of the m. abductor digiti I longus observed in P. cancrivorus has been previously described (Lima et al., 2010), while it was also reported originated from the ulna and the interosseus membrane (Santos et al., 2010). Therefore, both studies differ from our findings in P. cancrivorus, where the origin reaches both bones and the interosseus ligament, and an insertion onto the sesamoid bone was found. In other procyonids, such us in P. lotor, Nasua and P. flavus, the origin from the radius, the interosseus ligament and the ulna is common (Allen, 1882; Julitz, 1909; Mcclearn, 1985; Vélez-García et al., 2021). Although in Nasua, the radial origin can be absent (Mackintosh, 1875; Santos et al., 2010b). However, an insertion onto the sesamoid bone can occur (Mackintosh, 1875), similar to P. flavus (Vélez-García et al., 2021), and P. cancrivorus. In P. flavus, it can also insert onto the radial carpal bone (Beswick-Perrin, 1981), similar to P. lotor (Windle & Parsons, 1897). In mustelids, such as Martes and P. pennanti, the m. abductor digiti I longus originates from the radius and the ulna, and inserts onto the metacarpal bone I (Leach, 1976; Böhmer et al., 2018). Although in M. foina, it can originate from the interosseous antebrachial ligament, and inserts onto the sesamoid bone (Mackintosh, 1875). In E. barbara, this muscle only originates from the ulna and inserts onto the metacarpal bone I, the sesamoid bone and carpal I (Macalister, 1873). In G. cuja, Aonyx, and E. lutris, it originates from the radius and the ulna, and inserts onto the sesamoid bone and the metacarpal I (Macalister, 1870; Howard, 1973; Ercoli et al., 2015). In T. taxus, it is described as “extensor pollicis brevis”, which only originates from the radius and inserts onto the metacarpal bone I (Moore et al., 2013). In ursids, it originates from the radius, the ulna, and the interosseous membrane, and inserts onto the metacarpal I (Haughton, 1864; Shepherd, 1883; Kelley, 1888), although in A. melanoleuca, it only inserts onto the sesamoid bone (Davis, 1964). In Ailurus, it has the same origins, but fuses with the m. supinator and inserts onto the sesamoid bone and the metacarpal bone I (Anton et al., 2006; Fisher et al., 2009). In canids, it only originates from the radius and the ulna (Vaz et al., 2011; Souza-Junior et al., 2018; Smith et al., 2020), although, it can also originate from the interosseus membrane and inserts onto the sesamoid bone and metacarpal bone I in C. l. familiaris (Hermanson, 2013) and L. pictus (Smith et al., 2020). In felids, it originates from the radius, the ulna, and the interosseus membrane (Julik et al., 2012; Sánchez et al., 2019; Dunn et al., 2022), however, it is reported to only originate from the radius and the ulna in L. lynx (Viranta et al., 2016; Ari et al., 2019), P. leo (Barone, 1986; Vargas et al., 2017) and P. uncia (Smith et al., 2021). Whereas in Puma concolor, it only originates from the ulna and only inserts onto the metacarpal bone I (Concha et al., 2004). In L. pardalis, P. leo and P. tigris, it also inserts onto the sesamoid bone (Barone, 1986; Julik et al., 2012; Dunn et al., 2022), and in L. lynx onto the carpal bone I (Ari et al., 2019). In herpestids and viverrids of the genera Genetta and Civettictis, it originates from the radius and the ulna (Young, 1880; Taylor, 1976). However, in C. civetta, it has been reported to only originate from the ulna, and insert onto the metacarpal bone I and the sesamoid bone (Mackintosh, 1875). In hyaenids, it originates from the ulna, the radius, and the interosseus membrane, and inserts onto the metacarpal bone I (Watson & Young, 1876; Spoor & Badoux, 1985). In H. hyaena, it can also have an insertion onto the sesamoid bone, similar to H. aurupunctatus (Böhmer et al., 2020).

The m. extensor digiti I et II was not reported by Lima et al. (2010) and Santos et al. (2010a) in P. cancrivorus, whereas Windle (1888) reported this muscle as a deep digital extensor that originated from the radial border of the ulna with tendons to the digits I and II. However, this last author did not report a tendon extending to the digit III as our findings in four specimens did. In other procyonids, it also extends a tendon to the digit III, such in P. lotor, N. nasua, and N. narica (Mackintosh, 1875; Allen, 1882; Mcclearn, 1985), being similar to our findings in P. cancrivorus. Although, the tendon to the digit III can be absent in N. nasua (Mackintosh, 1875; Böhmer et al., 2020) and P. lotor (Windle & Parsons, 1897), while in P. flavus the absence of this tendon is normal (Beswick-Perrin, 1871; Windle & Parsons, 1897; Julitz, 1909; Vélez-García et al., 2021). Interestingly, in P. flavus has been found an independent muscle to the digit III, but as an anatomical variant (Vélez-García et al., 2021). Böhmer et al. (2020) only reported the tendon to the digit II in P. flavus, which may also be interpreted as an anatomical variant since it was always present in other studies (Beswick-Perrin, 1871; Windle & Parsons, 1897; Julitz, 1909; Vélez-García et al., 2021). Mackintosh (1875) reported that this muscle is one-headed in Nasua, while Mcclearn (1985) describes it as two separate bellies in P. lotor and Nasua, similar to P. cancrivorus. In mustelids, it originates from the ulna and extends tendons to the digits I and II (Macalister, 1870, 1875; Howard, 1973; Moore et al., 2013; Böhmer et al., 2018, 2020), however, in M. americana, P. pennanti, and G. cuja, it also originates from the m. abductor digiti I longus (Leach, 1976; Ercoli et al., 2015), which is similar to Ailurus (Fisher et al., 2009), and P. cancrivorus. Although in G. cuja, it also originates from the septum of the m. flexor digitorum profundus (Ercoli et al., 2015), and the case of Lutra vulgaris, it only goes to the digits II and III (Haughton, 1864). In Ursus it can be absent or fused with the m. abductor digiti I longus (Shepherd, 1883; Kelley, 1888), although when it is present, only extends the tendons to the digit I (Haughton, 1864); whereas in the genus Ailuropoda, it extends tendons to the digits I and II (Davis, 1964). In canids, the muscle originates from the ulna, but it has different distribution of the tendons. In C. l. familiaris, C. thous, and L. gymnocercus, it forms two tendons to the digits I and II, and sometimes to the digit III, where the tendon to the digit I goes to the head of the metacarpal bone I and the other to the extensor digitorum communis tendon for digit II (Hermanson, 2013; Vélez et al., 2015; Souza-Junior et al., 2018). In. C. thous, it also originates from the m. abductor digiti I longus and interosseous ligament (Vélez et al., 2015). In L. pictus, the medial tendon inserts onto the base of the metacarpal bone II (Smith et al., 2020). In C. alpinus and V. vulpes, the tendons to the digits I and II insert onto the distal phalanxes (Böhmer et al., 2020). In felids, it originates from the ulna and extends tendons to the digits I and II (Barone, 1967; Concha et al., 2004; Julik et al., 2012; Vargas et al., 2017; Sánchez et al., 2019; Böhmer et al., 2020; Smith et al., 2021). However, the lateral tendon can send a small fascicle to the tendon for digit III of the m. extensor digitorum lateralis in P. tigris (Dunn et al., 2022). In hyaenids, the m. extensor digiti I et II only goes to the digit II (Watson & Young, 1879; Spoor & Badoux, 1985; Böhmer et al., 2020) or digit III in Proteles (Watson, 1882). In viverrids, herpestids and euplerids the origin is also from the ulna and the muscle extends tendons to the digits I and II (Watson, 1882; Taylor, 1976; Böhmer et al., 2020).

The m. supinator in P. cancrivorus has been described as originating only from the orbicular ligament (Windle, 1888) or only from the lateral epicondyle (Santos et al., 2010a; Silva et al., 2015). We found a wide origin including the lateral collateral ligament of the elbow and the radial annular ligament, similar to P. flavus (Vélez-García et al., 2021). Whilst the insertion onto the proximal third of the radius was similar to that previously reported (Silva et al., 2015). In P. lotor, it originates from the orbicular ligament and inserts onto the proximal third (Allen, 1882) or proximal half (Windle & Parsons, 1897) of the body of the radius. In procyonids of the genus Nasua, it originates from the lateral epicondyle and inserts onto the proximal two-thirds of the radius (Mackintosh, 1875; Santos et al., 2010b), whereas in P. flavus it inserts onto the proximal half or proximal two-thirds (Windle & Parsons, 1897; Julitz, 1909; Vélez-García et al., 2021). In mustelids, there are several origins and insertions, such as in M. foina, where it inserts onto the proximal half (Mackintosh, 1875); in T. taxus it originates from the humeral condyle and the radius, and inserts onto length of the radius (Moore et al., 2013); in G. cuja, it originates from the articular capsule of the elbow and the lateral collateral ligament, and inserts onto the proximal two-thirds (Ercoli et al., 2015); in M. americana and P. pennanti, it originates from the lateral epicondyle and the lateral collateral ligament, and according to the figures inserts onto the proximal third of the radius (Leach, 1976); while in M. foina and M. martes it originates from the humerus and inserts until the distal third of the radius (Böhmer et al., 2018); in Mustela putorius, L. vulgaris and Aonyx cinereus, it reaches the third quarter of the radius (Windle & Parsons, 1897); in E. lutris it originates from the lateral epicondyle and inserts onto the proximal three fourths of the radius (Howard, 1973); and in Aonyx, it can inserts onto the distal third of the radius (Macalister, 1870). In Ailurus, it only originates from the lateral collateral and the radial annular ligament, and inserts onto the proximal half of the radius, fuses with the m. abductor digiti I longus (Fisher et al., 2009). In ursids, the origin is similar to that of Ailurus, but it inserts onto the proximal three-quarters of the radius (Shepherd, 1883; Kelley, 1888; Windle & Parsons, 1897; Davis, 1964). In canids, it originates from the lateral epicondyle and lateral collateral ligament, and inserts onto the proximal quarter of the radius (Hermanson et al., 2013; Smith et al., 2020); in L. gymnocercus and C. thous, it only originates from the lateral epicondyle and inserts onto the proximal third (Silva et al., 2015). In felids, it originates from the lateral epicondyle and inserts onto the middle third (Vargas et al., 2017), until the distal third of the radius (Barone, 1967). In L. lynx, it originates from the lateral epicondyle and lateral collateral ligament, and inserts onto almost length of the radius (Viranta et al., 2016); in P. concolor onto the middle third (Concha et al., 2004); in A. jubatus onto the quarter proximal (Hudson et al., 2011; Nazem et al., 2017). In L. pardalis, it originates from the radial annular and lateral collateral ligaments, and inserts onto the proximal two-thirds (Julik et al., 2012; Sánchez et al., 2019), while in P. onca, it inserts onto the distal third (Sánchez et al., 2019). In P. uncia, it originates from the lateral epicondyle of the humerus and inserts onto the proximal two thirds of the radius (based on the figures of Smith et al., 2021). While in P. tigris, it originates from the elbow articular capsule and adjacent ligaments, and inserts onto the proximal half of the radius and m. abductor longus digiti I (Dunn et al., 2022). In herpestids, it inserts onto the proximal two-thirds, while in viverrids, it inserts onto the proximal third of the radius (Windle & Parsons, 1897; Taylor, 1976) (Tab. I).

Tab. I.
Main differences of the craniolateral forearm muscles among carnivorans based on the literature review and the results of this study (O: origin, I: insertion).

Muscle	Main differences	Species
Brachioradialis	O: lateral supracondylar crest of the humerus	Procyonids, mustelids, a ursid (U. americanus), and felids (Caracal, Acynonyx and Leopardus)
	O: proximal third of the humerus	Mustelids (Family Ictonychidae), and felids (Panthera and Leopardus)
	O: middle third of the humerus	Mustelid (G. cuja) and felids
	O: lateral epicondyle of the humerus	Mustelid (T. taxus)
	Two heads	Ailurus and ursids (but U. americanus)
	I: cranial surface of the radius	Herpestids (I. albicauda and H. ichneumon)
	I: proximal row of the carpus	Felids (L. pardalis, L. geoffroyi and P. onca)
	I: flexor retinaculum	A felid (L. pardalis)
	Absent or vestigial	Canids, hyaenids, viverrids (Civettictis), and a felid (Acynonyx)
Extensor carpi radialis	Single muscle	A mustelid (G. cuja), Ailurus, ursids (Ursus), canids, hyaenids, herpestids, viverrids, and felids (C. caracal, A. jubatus and L. lynx)
	Partly fused	Procyonids (P. cancrivorus and N. nasua) and felids (F. catus, L. pardalis, P. leo, P. uncia, P. tigris, and L. lynx)
	Double muscle (Extensor carpi radialis longus and extensor carpi radialis brevis)	Procyonids (P. lotor, P. flavus and N. narica), mustelids (M. foina, M. martes, M. meles and as anatomical variant in G. cuja), Ailurus (only as an anatomical variant), and a ursid (A. melanoleuca)
	O: adjacent intermuscular septum	Procyonids (P. cancrivorus and P. flavus) and canids (C. l. familiaris and C. thous)
	O: articular capsule of the elbow joint	A canid (Cerdocyon thous)
	O: Fused with the m. extensor digitorum communis	Felids (L. pardalis and as an anatomical variant in P. tigris) and mustelids (M. americana and P. pennanti)
Extensor digitorum communis	O: lateral supracondylar crest of the humerus	Procyonids (P. lotor, N. nasua and N. narica), mustelids (M. foina, M. martes, M. americana and P. pennanti), a ursid (A. melanoleuca), felids (L. pardalis, A. jubatus, P. leo, P. uncia, and P. tigris), herpestids and viverrids (Genetta)
	O: lateral epicondyle of the humerus	A procyonid (P. flavus), a mustelid (T. taxus), Ailurus, ursids (Ursus), canids, felids, hyaenids and viverrids (Civettictis)
	O: lateral supracondylar crest and epicondyle of the humerus	A procyonid (P. cancrivorus), and mustelids (G. cuja and E. lutris)
	O: antebrachial fascia	A procyonid (P. cancrivorus) and canids (C. l. familiaris and C. thous)
	O: intermuscular adjacent septa	Procyonids (P. cancrivorus and P. flavus), canids (C. l. familiaris and C. thous), and a hyaenid (C. crocuta)
	O: fused with the m. extensor carpi radialis brevis	Felid (L. pardalis and as an anatomical variant in P. tigris) and mustelids (M. americana and P. pennanti)
	Tendon to the digit I as an anatomical variant	Procyonid (P. cancrivorus), mustelid (M. foina), and felids (P. leo and L. lynx)
Extensor digitorum lateralis	O: lateral epicondyle of the humerus	Procyonids (P. lotor and Nasua), mustelids (M. foina and M. martes), ursids (Ursus), a canid (L. gymnocercus) and felids
	O: lateral supracondylar crest	Felids (C. caracal, L. pardalis, P. onca and P. concolor)
	O: lateral epicondyle of the humerus and lateral collateral ligament	Procyonids (P. cancrivorus and P. flavus), and canids (C. l. familiaris, C. thous, and L. pictus)
	Double muscle	A procyonid (N. narica), and mustelids (Aonyx, G. cuja, and T. taxus)
	O: lateral epicondyle of the humerus and radius	Mustelids (M. americana and P. penannti) and a hyaenid (H.hyaenae)
	O: lateral epicondyle and condyle of the humerus	Ursid (A. melanoleuca)
	O: antebrachial fascia	A procyonid (P. cancrivorus) and a canid (C. thous)
	O: intermuscular adjacent septum	Procyonids (P. cancrivorus and P. flavus) and a canid (C. thous)
	Absence of the tendon to the digit III	Mustelids (M. martes, M. foina and E. lutra), ursid (A. melanoleuca), canids (C. alpinus, V. vulpes, and as anatomical variant in L. gymnocercus), herpestids, viverrids (but C. civetta), and hyaenids
	Presence of a tendon to the digit II	Felids (F. catus, P. tigris and L. pardalis)
Extensor carpi ulnaris	O: lateral epicondyle of the humerus	Procyonids (P. cancrivorus), mustelids, ursids, Ailurus, canids, felids, herpestids, hyaenids, and viverrids
	O: lateral epicondyle of the humerus and articular capsule of the elbow	Procyonid (P. flavus), mustelid (G. cuja), and a felid (L. pardalis)
	O: lateral epicondyle of the humerus and the ulna	Procyonids (N. narica, as an anatomical variant in P. cancrivorus and P. flavus), felid (L. lynx), viverrids (Genetta)
	I: metacarpal bone V and accessory carpal bone	Procyonids (P. cancrivorus, and P. flavus, and as anatomical variant in P. lotor), mustelids (but T. taxus, M. martes and M. foina), Ailurus, canids , felids (but L. lynx, L. pardalis, P. uncia and P. tigris), herpestids, and viverrids
	I: metacarpal bone V and extensor retinaculum	Felid (L. lynx) and a hyaenid (Proteles)
Abductor digiti I longus	Absence of the origin from the radius	Procyonid (Nasua as an anatomical variant), a mustelid (E. barbara), and a felid (P. concolor)
	Absence of the origin from the ulna	A mustelid (T. taxus), and a viverrid (C. civetta)
	I: sesamoid bone and metacarpal bone I	Procyonids (P. cancrivorus, Nasua, P. flavus), mustelids (G. cuja, Aonyx, E. lutris, E. barbara and M. foina), Ailurus, canids, felids (L. pardalis, P. leo and P. tigris), hyaenids and a viverrid (C. civetta)
	I: only onto sesamoid bone	A ursid (A. melanoleuca) and a mustelid (M. foina as an anatomical variant)
	I: carpal bone I	A mustelid (E. barbara) and a felid (L. lynx as an anatomical variant)
	I: radial carpal bone	Procyonids (as an anatomical variant in P. flavus and P. lotor)
Extensor digiti I et II	Presence of a tendon to the digit III	Procyonids (P. cancrivorus, N. nasua and P. lotor), canids (as an anatomical variant in C. l. familiaris, C. thous, and L. gymnocercus), and a felid (P. tigris)
	A unique tendon to the digit II	Hyaenids
	A unique tendon to the digit III	Hyaenid (Proteles)
	Tendons only to the digits II and III	A mustelid (L. vulgaris)
	Absent or fused to the abductor digiti I longus and sending tendon only to the digit I	Ursids (Ursus)
	I: metacarpal bone I and tendon of the extensor digitorum communis to the digit II	Canids (but C. alpinus and V. vulpes)
	I: distal phalanges of the digits I and II	Canids (C. alpinus and V. vulpes)
Supinator	O: only from the lateral epicondyle	A mustelid (E. lutra), canids (L. gymnocercus and C. thous), and felids
	O: lateral epicondyle and lateral collateral ligament	Mustelids (M. americana, and P. pennanti,), canids and felids (L. lynx, A. jubatus, P. concolor)
	O: lateral epicondyle, lateral collateral and radial annular ligaments	Procyonids (P. cancrivorus, P. flavus and P. lotor)
	O: lateral collateral and radial annular ligaments	A felid (L. pardalis), Ailurus and ursids
	O: articular capsule of the elbow joint and lateral collateral ligament	Mustelid (G. cuja)
	I: proximal third of the radius	Procyonids (P. cancrivorus and P. lotor), canids (L. gymnocercus and C. thous) and viverrids
	I: proximal two thirds of the radius	Procyonids (Nasua, P. flavus and P. lotor), mustelids (M. americana, P. pennanti, G. cuja), felid (L. pardalis), herpestids
	I: proximal half of the radius	Procyonid (P. flavus and P. lotor), mustelids (M. foina)
	I: Along the radius	Mustelid (T. taxus)
	I: distal third of the radius	Mustelids (M. foina, M. martes and Aonyx), felid (P. onca)
	I: middle third	Felid (P. concolor)
	I: proximal three quarters of the radius	Mustelids (Mustela putorius, L. vulgaris A. cinereus, and E. lutris), and ursids
	I: proximal quarter of the radius	Canids (C. l. familiaris and L. pictus), and a felid (A. jubatus)

Functional analysis. Within the craniolateral forearm muscles of P. cancrivorus, the brachioradialis and supinator muscles are two muscles that should act as lateral rotators of the antebrachium and manus (supinators). Based on Kardong (2012), when the muscle is inserted proximally, it acts for fast movements, while when it is inserted distally, it acts for strong movements. Therefore, in P. cancrivorus, the proximal insertion of the m. supinator should give it more velocity to supination, while the m. brachioradialis due to its distal insertion gives it more force to supination. The proximal insertion of the m. supinator also is present in other carnivorans mainly with cursorial habits, such as canids, hyaenids, viverrids, and the felid A. jubatus. However, the permanent presence of a well-developed m. brachioradialis in P. cancrivorus has allowed it to perform more activities, such as manipulating its food with its hands, swimming, and climbing trees. Since carnivoran species with a well-developed m. brachioradialis can perform more activities with their thoracic limbs than just walking and running (Indrusiak & Eizirik, 2003; Martinelli & Volpi, 2010; Pellanda et al., 2010; Souza et al., 2015; Souza-Junior et al., 2015; Taverne et al., 2018). Additionally, this muscle contributes to elbow flexion in carnivorans, but this action is secondary due to its insertion onto the distal part of the forearm (Saladin, 2010; Souza et al., 2015, 2020). Interestingly, other mammals as Primates with similar attachments to P. cancrivorus, the primary function of the m. brachioradialis is to flex the elbow (Myatt et al., 2012) and stabilize the elbow during flexion tasks (Boland et al., 2008). Therefore, the m. brachioradialis should flex and stabilize the elbow together to the extensor carpi radialis and extensor digitorum communis muscles in P. cancrivorus since these also originate from the lateral supracondylar crest. Thereby, procyonid species have a pronounced lateral supracondylar crest to give origin to these muscles (Taverne et al., 2018; Tarquini et al., 2019; Vélez-García et al., 2021), which is a characteristic of carnivorans with arboreal abilities (Taylor, 1976; Argot, 2001; Fabre et al., 2015; Taverne et al., 2018). On the other hand, the proximal origins of brachioradialis, extensor carpi radialis and extensor digitorum communis muscles could be associated with the feeding habits of P. cancrivorus when the individual needs to be flexing the elbow to bring food to its mouth with its hands.

The m. extensor carpi radialis is mainly an extensor of the carpus and can be present as a single or double muscle in a common or variant manner in carnivorans. Therefore, there should be no functional differences among carnivorans, but the constant arrangement as a single muscle in P. cancrivorus allows to differentiate it of P. lotor. Thus, during the phylogenetic divergence of both species, the muscles extensor carpi radialis longus and brevis were separated in P. lotor (based on the descriptions of Allen, 1882, Mcclearn, 1985 and Taverne et al., 2018) and remained partlty fused in P. cancrivorus.

The m. extensor carpi ulnaris in P. cancrivorus should act as an abductor of the carpal joint and extensor or flexor of the carpus when the carpal joint is already extended or flexed respectively, such as occur in other carnivorans (Singh, 2018; Smith et al., 2020; Vélez-García et al., 2021). The extensor carpi radialis and the abductor digiti I longus muscles could counteract the action of the m. extensor carpi ulnaris abducting the carpus in P. cancrivorus. Thereby, these actions allow more movements of its hands due to the high handling habilities of the genus Procyon (Mcclearn, 1992).

The m. extensor digitorum communis extends the digits II to V and in some variant cases in P. cancrivorus, it also extends the digit I similar to M. foina (Böhmer et al., 2020) and some felids (Viranta et al., 2016; Vargas et al., 2017). Therefore, that tendon is a characteristic that could have had the common ancestor of the carnivorans when the digit I was more functional, and thus it can appear in species with high use of the digit I, such as musteloids and felids. However, the extension of the digit I in all carnivorans is always performed by the abductor digiti longus I and extensor digiti I et II muscles. This latter muscle, in the case of P. cancrivorus also supports the extension of the digit III, although this support is not always necessary since the tendon to this digit can be absent (Windle, 1888). However, the higher proportion of presentation of this tendon in P. cancrivorus allows us to infer that the common ancestor of the caniformes had it, therefore it may be present in other caniformes species as an anatomical variant and a phylogenetic trait. On the other side, the extension of the digits III to V is supported by the m. extensor digitorum lateralis, such as occur in most carnivorans.

This study confirms that P. cancrivorus has intraspecific variations that anatomically are related to other carnivorans, such as the tendon for the digit I from the m. extensor digitorum communis, the origin from the ulna of the m. extensor carpi ulnaris, the origins from the antebrachial fascia and the intermuscular septa of the extensor digitorum communis and lateralis muscles. In contrast, another intraspecific variation was not related to other carnivorans, such as the origin of the m. abductor I digiti longus from the lateral collateral ligament of the elbow. Therefore, it could be a proper anatomical variation of P. cancrivorus based on the comparative review. On the other side, the brachioradialis, extensor carpi radialis, supinator, and extensor digiti I et II are the most anatomically variant muscles among carnivoran species. However, there are only functional differences when there is a well-developed m. brachioradialis, and when the distribution of tendons is different from the digital extensor muscles.

REFERENCES

• Allen, H. 1882. The muscles of the limbs of the raccoon (Procyon lotor). Proceedings of the Academy of Natural Sciences of Philadelphia 34(2):115-144.
• Argot, C. 2001. Functional‐adaptive anatomy of the forelimb in the Didelphidae, and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus Journal of Morphology 247(1):51-79.
• Ari, H.; Yurdakul, İ. & Aksoy, G. 2019. A macroscopic study on the muscles and tendons of forepaws in the anatolian bobcat (Lynx lynx). Slovenian Veterinary Research 56(4):153-162
• Aversi-Ferreira, T. A.; Aversi-Ferreira, R. A.; Silva, Z.; Gouvêa E Silva, L. F. & Penha-Silva, N. 2005. Estudo anatômico de músculos profundos do antebraço de Cebus apella (Linnaeus, 1766). Acta Scientiarum, Biological Sciences 27:297-301.
• Barone, R. 1967. La myologie du lion (Panthera leo). Mammalia 31:459-514.
• Barone, R. 1980. Anatomie comparée des Mammifères Domestiques 2nd tome: Arthrologie et Myologie. Vigot, Paris. 984p.
• Beswick-Perrin, J. 1871. On the myology of the limbs of the kinkajou (Cercoleptes caudivolvulus). Proceedings of the Zoological Society of London 1871:547-559.
• Böhmer, C.; Fabre, A. C.; Taverne, M.; Herbin, M.; Peigne, S. & Herrel, A. 2018. Anatomical basis of differences in locomotor behavior in martens: a comparison of the forelimb musculature between two sympatric species of Martes The Anatomical Record 301(3):449-472.
• Böhmer, C.; Theil, J. C.; Fabre, A. C. & Herrel, A. 2020. Atlas of terrestrial mammal limbs. Boca Raton, CRC Press. 383p.
• Boland, M. R.; Spigelman, T. & Uhl, T. L. 2008. The function of brachioradialis. The Journal of Hand Surgery 33(10):1853-1859.
• Concha, I.; Adaro, L.; Borroni, C. & Altamirano, C. 2004. Consideraciones anatómicas sobre la musculatura intrínseca del miembro torácico del puma (Puma concolor). Journal of Morphology 22:121-125.
• Cubas, Z. S.; Silva, J. C. R. & Catão-Dias, J. L. 2006. Carnívora-Procyonidae (Quati, Mão-pelada, Jupará). Tratado de animais selvagens-medicina veterinária. São Paulo, Roca, p. 571-582.
• Cuff, A. R.; Sparkes, E. L.; Randau, M.; Pierce S. E.; Kitchener A. C.; Goswami, A. & Hutchinson, J. R. 2016. The scaling of postcranial muscles in cats (Felidae) I: forelimb, cervical, and thoracic muscles. Journal of Anatomy 229(1):128-141.
• Davis, D. 1964. The giant panda a morphological study of evolutionary mechanisms. Chicago, Natural History Museum Chicago 3:1-339.
• Devis, C. W. 1868. Notes on the myology of Viverra civetta Journal of Anatomy 2:207-217.
• Diogo, R. & Abdala, V. 2010. Muscles of vertebrates: comparative anatomy, evolution, homologies and development. Boca Raton, CRC Press. 500p.
• Dunn, R. H.; Beresheim, A.; Gubatina, A.; Bitterman, K.; Butaric, A.; Bejes, K.; Kennedy, S.; Markham, S.; Miller, D.; Mrvoljak, M.; Roge-Jones, L.; Stumpner, J.; Walter, C. & Meachen, J. A. 2022. Muscular anatomy of the forelimb of tiger (Panthera tigris) . Journal of Anatomy. https://doi.org/10.1111/joa.13636
  » https://doi.org/10.1111/joa.13636
• Echeverry, J. S.; Vélez, J. F. & Sánchez, C. A. 2015. Descripción anatómica de los músculos cráneo-laterales superficiales del antebrazo del zorro perruno (Cerdocyon thous). Revista Colombiana de Ciencia Animal 8(1):44-51.
• Ercoli, M. D.; Álvarez, A.; Stefanini, M. I.; Busker, F. & Morales, M. M. 2015. Muscular anatomy of the forelimbs of the lesser grison (Galictis cuja), and a functional and phylogenetic overview of Mustelidae and other Caniformia. Journal of Mammalian Evolution 22(1):57-91.
• Evans, H. E. & De Lahunta, A. 2017. Guide to the Dissection of the Dog. 5ed. St. Louis Missouri, Elsevier Health Sciences. 327p.
• Fabre, A. C.; Cornette, R.; Goswami, A. & Peigné, S. 2015. Do constraints associated with the locomotor habitat drive the evolution of forelimb shape? A case study in musteloid carnivorans. Journal of Anatomy 226(6):596-610.
• Fisher, R. E.; Adrian, B.; Barton, M.; Holmgren, J. & Tang, S. Y. 2009. The phylogeny of the red panda (Ailurus fulgens): evidence from the forelimb. Journal of Anatomy 215:611-635.
• Haughton, S. 1864. Notes on Animal Mechanics: No. 15. On the Muscular Anatomy of the Otter (Lutra vulgaris). Proceedings of the Royal Irish Academy 9:511-515.
• Hermanson, J. W. 2013. The Muscular System. In: Evans, H. E. & De Lahunta, A. eds. Miller’s anatomy of the dog. Missouri, Saunders Elsevier, p. 185-280.
• Howard, L. D. 1973. Muscular anatomy of the forelimb of the sea otter (Enhydra lutris). Proceedings of the California Academy of Sciences 39(20):411-500.
• Hudson, P. E.; Corr, S. A.; Payne‐Davis, R. C.; Clancy, S. N.; Lane, E. & Wilson, A. M. 2011. Functional anatomy of the cheetah (Acinonyx jubatus) forelimb. Journal of Anatomy 218(4):375-385.
• Indrusiak, C. & Eizirik, E. 2003. Carnívoros. In: Fontana, C. S.; Bencke, G. A. & Reis, R. E. orgs. Livro vermelho da fauna ameaçada de extinção do RS. Porto Alegre, Edipucrs, p. 507-533.
• Icvgan - International Committee On Veterinary Gross Anatomical Nomenclature. 2017. Nomina Anatomica Veterinaria. 6ed. Hannover, World Association of Veterinary Anatomists. 160p.
• Julik, E.; Zack, S.; Adrian, B.; Maredia, S.; Parsa, A.; Poole, M.; Starbuck, A. & Fisher, R. E. 2012. Functional anatomy of the forelimb muscles of the ocelot (Leopardus pardalis). Journal of Mammalian Evolution 19(4):277-304.
• Julitz, C. 1909. Osteologie und myologie der Extremitäten und des Wickelschwanzes vom Wickelbären, Cercoleptes caudivolvulus, mit besondere Berücksichtigung der Anpassungserscheinungen an das Baumleben. Archiv für Naturgeschichte Berlin 75:143-188.
• Kardong, K. V. 2012. Vertebrates: comparative anatomy, function, evolution. 6ed. New York, McGraw Hill. 794p.
• Kelley, E. A. 1888. Notes on the myology of Ursus maritimus The Proceedings of the Academy of Natural Sciences of Philadelphia 40:141-154.
• Labate, A.; Nunes A. L. & Gomes, M. 2001. Order Carnivora, Family Procyonidae (Raccoons, kinkajous). In: Fowler, M. E. & Cubas, Z. S. eds. Biology, Medicine and Surgery of South American Wild Animals. Iowa, Iowa State University Press, p. 317-322.
• Leach, D. 1976. The forelimb musculature of marten (Martes americana Turton) and fisher (Martes pennanti Erxleben). Canadian Journal of Zoology 55(1):31-41.
• Liebich, H. G.; Maierl, J. & König, H. E. 2020 Forelimb or thoracic limb (Membra thoracica). In: König, H. E. & Liebich, H. G. eds. Veterinary Anatomy of Domestic Mammals: Text Book and Colour Atlas. New York, Thieme, p. 171-242.
• Lima, V. M.; Pereira, F. C. & Pereira, K. F. 2010. Morphological study of the muscles of the forearm of crab eating raccoon Procyon cancrivorus Cuvier, 1798. Bioscience Journal 26(1):109-114.
• Macalister, A. 1873. On the anatomy of Aonyx Proceedings of the Royal Irish Academy 1:539-547.
• Mackintosh, H. W. 1875. Notes on the Myology of the Coati-Mondi (Nasua narica and N. fusca) and Common Martin (Martes foina). Proceedings of the Royal Irish Academy 2:48-55.
• Martinelli, M. M. & Volpi, T. A. 2010. Diet of racoon Procyon cancrivorus (Carnivora, Procyonidae) in a mangrove and restinga area in Espírito Santo state, Brazil. Natureza on line 8:150-151.
• Massoia, E.; Chebez, J. C. & Bosso, A. 2012. Los mamíferos silvestres de la provincia de Misiones, Argentina. Buenos Aires, Fundación de Historia Natural Félix de Azara. 512p.
• Mcclearn, D. 1985. Anatomy of raccoon (Procyon lotor) and coati (Nasua narica and N. nasua) forearm and leg muscles: Relations between fiber length, moment‐arm length, and joint‐angle excursion. Journal of Morphology 183(1):87-115.
• Mcclearn, D. 1992. Locomotion, posture, and feeding behavior of kinkajous, coatis, and raccoons. Journal of Mammalogy 73(2):245-261.
• Moore, A. L.; Budny, J. E.; Russell, A. P. & Butcher, M. T. 2013. Architectural specialization of the intrinsic thoracic limb musculature of the American badger (Taxidea taxus). Journal of Morphology 274(1):35-48.
• Myatt, J. P.; Crompton, R. H.; Payne‐Davis, R. C.; Vereecke, E. E.; Isler, K., Savage, R. ... & Thorpe, S. K. 2012. Functional adaptations in the forelimb muscles of non‐human great apes. Journal of Anatomy 220(1):13-28.
• Nazem, M. N.; Sajjadian, S. M. & Nakhaei, A. 2017. Anatomy, functional anatomy and morphometrical study of forelimb column in Asiatic cheetah (Acinonyx jubatus venaticus). The Italian Journal of Anatomy and Embryology 3:157-172.
• Nowak, R. M. 1999. Walker’s Mammals of the World. 6ed. Baltimore, The John Hopkins University Press. 2015p.
• Nyakatura, K. & Bininda-Emonds, O. R. 2012. Updating the evolutionary history of Carnivora (Mammalia): a new species-level supertree complete with divergence time estimates. BMC Biology 10(1):1-31.
• Paranaiba, J. F.; Helrigle, C.; Araújo, E. G. D. & Pereira, K. F. 2012. Aspectos morfológicos da mão e pé de Procyon cancrivorus Natureza on line 10(4):165-169.
• Pellanda, M.; Castro-Almeida, C. M.; Dos Santos, M. D. & Hartz, S. M. 2010. Dieta do mão-pelada (Procyon cancrivorus, Procyonidae, Carnivora) no Parque Estadual de Itapuã, sul do Brasil. Neotropical Biology and Conservation 5(3):154-159.
• Perdomo‐Cárdenas, V.; Patiño‐Holguín, C. & Vélez‐García, J. F. 2021. Evolutionary and terminological analysis of the flexor digitorum superficialis, interflexorii and palmaris longus muscles in kinkajou (Potos flavus) and crab‐eating racoon (Procyon cancrivorus). Anatomia Histologia Embryologia 50(3):520-533.
• Saladin, K. S. 2010. Anatomy and Physiology: The Unity of Form and Function. New York, McGraw Hill . 1248p.
• Sánchez, H. L.; Rafasquino, M. E. & Portiansky, E. L. 2019. Comparative anatomy of the forearm and hand of wildcat (Leopardus geoffroyi), ocelot (Leopardus pardalis) and jaguar (Panthera onca). Journal of Morphological Science 36:7-13.
• Santos, A. C.; Bertassoli, B. & Rosa, R. A. 2010a. Miologia comparada do membro torácico do mão-pelada (Procyon cancrivorus G. Cuvier, 1798). Revista da FVZA 17(2):262-275.
• Santos, A. C.; Bertassoli, B. M.; De Oliveira, V. C.; De Carvalho A. F.; Rosa, R. A. & Mançanares, C. A. F. 2010b. Morfologia dos músculos do ombro, braço e antebraço do quati (Nasua nasua Linnaeus, 1758). Biotemas 23(3):165-173.
• Shepherd, F. J. 1883. Short notes on the myology of the American black bear (Ursus americanus). Journal of Anatomy 18:103-117.
• Silva, M. F.; Souza, W. V.; Almada, R. M.; Carvalho, A. D.; Souza Junior, P. & Rodovia, U. B. 2015. Anatomía comparada de los músculos supinador y pronador redondo de tres especies carnívoras silvestres. Revista Argentina de Anatomía Online 6(3):117-22.
• Singh, B. 2018. Dyce, Sack and Wensing’ textbook of veterinary anatomy. 5ed. St. Louis, Elsevier. 854p.
• Smith, H. F.; Adrian, B.; Koshy, R.; Alwiel, R. & Grossman, A. 2020. Adaptations to cursoriality and digit reduction in the forelimb of the African wild dog (Lycaon pictus). Peer Journal 8:1-34.
• Smith, H. F.; Townsend, K. B.; Adrian, B.; Levy, S.; Marsh, S.; Hassur, R.; Manfredi, K. & Echols, M. S. 2021. Functional adaptations in the forelimb of the snow leopard (Panthera uncia). Integrative and Comparative Biology 61(5):1852-1866.
• Souza-Junior, P.; De Souza Pahim, A. B.; Viotto‐Souza, W.; Pellenz, J.; Bernardes, F. C. S.; Abidu‐Figueiredo, M. & Santos, A. L. Q. 2021. Evolutionary history or function? Which preponderates in the expression of the muscle mass of the thoracic limb in wild carnivorans? The Anatomical Record 304(36):1344-1356.
• Souza-Junior, P. D.; Dos Santos, L. M.; Nogueira, D. M., Abidu-Figueiredo, M. & Santos, A. L. 2015. Occurrence and morphometrics of the brachioradialis muscle in wild carnivorans (Carnivora: Caniformia, Feliformia). Zoologia 32(1):23-32.
• Souza Junior, P.; Santos, L. M. R. P. D.; Viotto‐Souza, W.; De Carvalho, N. D. C.; Souza, E. C.; Kasper, C. B.; Abidu-Figueiredo, M. & Santos, A. L. Q. 2018. Functional myology of the thoracic limb in Pampas fox (Lycalopex gymnocercus): a descriptive and comparative analysis. Journal of Anatomy 233(6):783-806.
• Spoor, C. F. & Badoux, D. M. 1986. Descriptive and functional myology of the neck and forelimb of the striped hyena (Hyaena hyaena, L. 1758). Anatomischer Anzeiger 161:375-387.
• Tarquini, J.; Morgan, C. C.; Toledo, N. & Soibelzon, L. H. 2019. Comparative osteology and functional morphology of the forelimb of Cyonasua (Mammalia, Procyonidae), the first South American carnivoran. Journal of Morphology 280:446-470.
• Taverne, M.; Fabre, A. C.; Herbin, M.; Herrel, A.; Peigmé, S.; Lacroux, C.; Lowi, A.; Pagès, F.; Theil, J. C. & Böhmer, C. 2018. Convergence in the functional properties of forelimb muscles in carnivorans: adaptations to an arboreal lifestyle? Biological Journal of the Linnean Society 125:250-263.
• Taylor, M. E. 1976. The functional anatomy of the forelimb of some African Viverridae (Carnivora). Journal of Morphology 143(3):307-335.
• Vargas, J. F.; Quintana, O.; Barraza, C. & Olivares, R. 2017. Descripción anatómica de la musculatura intrínseca del miembro torácico de león (Panthera leo). International Journal of Morphology 35(3):1154-1160.
• Vaz, M. G. R.; De Lima, A. R.; De Souza, A. C. B.; Pereira, L. C. & Branco, E. 2011. Estudo morfológico dos músculos do antebraço de cachorro-do-mato-de-orelhas-curtas (Atelocynus microtis) e cachorro-do-mato (Cerdocyon thous). Biotemas 24(4):121-127.
• Vélez‐García, J. F.; Chunganá‐Caicedo, D. & Saavedra‐Montealegre, S. 2021. Gross anatomy of the craniolateral antebrachial muscles in kinkajou (Potos flavus, Carnivora): Intra‐and interspecific variants within the family Procyonidae. Anatomia, Histologia, Embryologia 51(2):308-313.
• Viranta, S.; Lommi, H.; Holmala, K. & Laakkonen, J. 2016. Musculoskeletal anatomy of the Eurasian lynx, Lynx lynx (Carnivora: Felidae) forelimb: adaptations to capture large prey? Journal of Morphology 277(6):753-765.
• Watson, M. 1882. On the Muscular Anatomy of Proteles as compared with that of Hyeena and Viverra Journal of Zoology 50(3):579-586.
• Watson, M. & Young, A. 1879. On the anatomy of the Hyaena crocuta (H. maculata). Journal of Zoology 47:79-107.
• Wilson, D. E. & Mittermeier, R. A. 2009. Handbook of the Mammals of the World, Vol. 1. Carnivores. Barcelona, Lynx Edicions. 727p.
• Windle, B. C. 1888. Notes on the Limb Myology of Procyon cancrivorus and of the Ursidœ. Journal of Anatomy 23(1):81-89.
• Windle, B. C. A. & Parsons, F. G. 1897. On the Myology of the Terrestrial Carnivora. Part I. Muscles of the Head, Neck, and Fore‐Limb. Journal of Zoology 66(2):370-409.
• Young, A. H. 1880. Myology of Viverra civetta Journal of Anatomy 14:166-177.

Publication Dates

• Publication in this collection
  03 June 2022
• Date of issue
  2022

History

• Received
  13 July 2021
• Accepted
  08 Apr 2022