chapter  7
Head and Neck Muscles of Reptiles
Pages 43

In this chapter we focus on the comparative anatomy, evolution and homologies of the head and neck muscles of the major extant clades of reptiles, that is, Testudines (turtles), Lepidosauria (including Sphenodon, ‘lizards’, mosasaurs, snakes and amphisbaenians sensu Conrad 2008: see below), Crocodylia (crocodylians), and Aves (birds). Many anatomical works have provided information about the head and neck musculature of reptiles (e.g., Fürbringer 1874, 1876; Albrecht 1876; Versluys 1898, 1904; Edgeworth 1911, 1935; Phisalix 1914; Adams 1919; Camp 1923; Lakjer 1926; Brock 1938; Engels 1938; Lightoller 1939; Walker 1954; Oelrich 1956; Schumacher 1961, 1973; Frazzetta 1962; Jollie 1962; Jarvik 1963, 1980; Iordansky 1964, 2000, 2004, 2008; Barghusen 1968, 1986; Gaunt and Gans 1969; Haas 1973; Vanden Berge 1975; Rieppel 1980, 1981, 1984, 1990; Ghetie et al. 1981; Busbey 1989; Elzanowski 1987; Smith 1988; Witmer 1995ab, 1997; Abdala and Moro 1996, 2003; Moro and Abdala 1998, 2000; Herrel et al. 1999, 2005; Wyneken 2001; Montero et al. 2002; Sedlmayr 2002; Holliday and Witmer 2007; Tsuihiji 2007; Conrad 2008; Tsukahara et al. 2009; Abdala et al. in press). However, as is the case with other vertebrate groups, most of these works focused on a specifi c reptilian taxon and/or a specifi c head and neck region, and none of them has actually provided detailed information about the homologies of the whole head and neck musculature of turtles, lepidosaurs, crocodylians and birds. The present account of the comparative anatomy, homologies and evolution of the head and neck muscles of these latter groups is based on the results of our own dissections of numerous members of each of these groups, combined with an exhaustive literature review. In fact, we made an effort to take into account as much bibliographical information as possible, from classic anatomical descriptions (e.g., Fürbringer 1874, 1876; Albrecht 1876; Versluys 1898, 1904; Edgeworth

1911, 1935; Phisalix 1914; Adams 1919; Lakjer 1926; Engels 1938; Lightoller 1939) to more recent reviews (e.g., Haas 1973; Schumacher 1973; Vanden Berge 1975; Gethie et al. 1981; Müller and Weber 1998; Noden et al. 1999; Iordansky 2000, 2008; Abdala and Moro 2003; Holliday and Witmer 2007; Conrad 2008; Holliday 2009; Abdala et al. in press), including, importantly, the developmental and molecular data obtained in the numerous evodevo studies that have been undertaken in the past few decades with both reptilian and non-reptiles tetrapods such as chickens, quails, salamanders, frogs and mice (e.g., Noden 1983, 1984, 1986; McClearn and Noden 1988; Davis et al. 1991; Couly et al. 1992; Gardner and Barald 1992; Köntges and Lumsden 1996; Huang et al. 1999; Marcucio and Noden 1999; Olsson et al. 2000, 2001, 2005; Ellies and Tucker 2002; Mootoosamy and Dietrich 2002; Borue and Noden 2004; Ericsson and Olsson 2004; Ericsson et al. 2004; Le Douarin et al. 2004; Prunotto et al. 2004; O’Gorman 2005; Yamane 2005; Noden and Francis-West 2006; Noden and Schneider 2006; Piekarski and Olsson 2007; Ziermann and Olsson 2007; Knight et al. 2008; Kundrát et al. 2009; Shearman and Burke 2009; Tzahor 2009). The results of our observations and comparisons are summarized in Tables 7.1-7.4, which present the best-supported hypotheses of homology for the muscles discussed in this chapter.