Comparative anatomy, homologies and evolution of the pectoral muscles of bony fish and tetrapods: A new insight

Abstract

The Osteichthyes, including bony fishes and tetrapods, is a highly speciose group of vertebrates, comprising more than 42,000 living species. The anatomy of osteichthyans has been the subject of numerous comparative studies, but most of these studies concern osteological structures; much less attention has been paid to muscles. The most detailed comparative analyses of osteichthyan pectoral muscles that were actually based on a direct observation of representatives of various major actinopterygian and sarcopterygian groups were provided several decades ago by authors such as Howell and Romer. Despite the quality of their work, these authors did not have access to much information that is now available. In the present work, an updated discussion on the homologies and evolution of the osteichthyan pectoral muscles is provided, based on the authors' own analyses and on a survey of the literature, both old and recent. It is stressed that much caution should be taken when the results obtained in molecular and developmental studies concerning the pectoral muscles of model actinopterygians such as the teleostean zebrafish are discussed and compared with the results obtained in studies concerning model sarcopterygians from clades such as the Amphibia and/or the Amniota. This is because, as shown here, as a result of the different evolutionary routes followed within the actinopterygian and the sarcopterygian clades none of the individual muscles found, for example, in derived actinopterygians such as teleosts is found in derived sarcopterygians such as tetrapods. It is hoped that the information provided in the present work may help in paving the way for future analyses of the pectoral muscles in taxa from different osteichthyan groups and for a proper comparison between these muscles in those taxa.

Description and scaling of pectoral muscles in ictalurid catfishes

“…There are now a separate abductor and adductor, in addition to muscles that elevate and depress the spine (the arrector dorsalis and arrector ventralis), and these arrectors contribute to spine abduction. Note that Diogo and Abdala (2007, 2010) claim a seventh pectoral muscle occurs in various euteleosts that corresponds to the arrector ventralis in the present article.…”

“…A variety of nomenclature has been used to describe the pectoral musculature of catfishes, most recently by Brousseau (1976), Diogo et al (2001), Diogo (2004), and Diogo and Abdala (2007) (Table 2). Some terms are potentially confusing because names do not always correspond to muscle function.…”

“…Howes (1985) suggested that the spine adductor is related to either the adductor superficialis or to the adductor superficialis and profundus of other teleosts. Diogo and Abdala (2007), however, suggest that this muscle is his arrector dorsalis, which is present in catfishes and most teleosts including Amia and Lepisosteus but not in other vertebrates (Diogo and Abdala,2010).…”

Functional study of the pectoral spine stridulation mechanism in different mochokid catfishes

“…The left pectoral girdle and spine were dissected under a binocular dissecting microscope (Wild M5) to observe the pectoral girdle morphology and muscles associated with the pectoral spine. The muscle nomenclature is based on the work of Diogo and Abdala (Diogo and Abdala, 2007). Spines and pectoral girdles were then cleaned in distilled water and dehydrated through an ethanol series (50%, 75% and 100%), critical-point dried and platinum sputter-coated (20 nm) in a Balzers SCD-030 sputter unit.…”

The adductor pectoral fin muscle of Micropogonias furnieri (Perciformes: Sciaenidae): a morphological and histochemical study

“…However, the presence and morphology of these muscles vary among species (thOrsen & hale 2005(thOrsen & hale , mianO et al 2013. For instance, according to DiOgO & aBDala (2007) in Danio rerio (Hamilton, 1822) the superficial and deep adductor muscles are not individualized, but comprise a single entity. In M. furnieri, on the other hand, these muscles are separated by connective tissue into two fascicles, and are thus considered individual muscles.…”