Pelvic Appendage Myology of the Hawaiian Honeycreepers (drepanididae)

THts is the first in a series of studies on the appendicular myology and relationships of passerine birds. Despite the many studies that have been done to clarify relationships within the largest order of birds, the interrelationships of passeriform families are still a matter of great confusion. Relatively few anatomical studies have been done on passerines as compared to nonpasserine orders, and most of these (such as Beecher 1953, Tordoff 1954, Bock 1960) have dealt with the structure of the head or the pterylosis (Clench 1970). Few studies have been carried out on the appendicular muscles of passerine birds, and most of these (e.g. Berger 1968, Gaunt 1969) have been limited to single species or families. Hudson (1937) compared a few passerine species with various nonpasserine forms, and Stallcup (1954) and Swinebroad (1954) made limited interfamilial comparisons. Berger (1969) reviewed the present state of knowledge of the subject and emphasized how little still is known about the appendicular myology of passerines. The need for new studies of passerine relationships using previously unutilized sources of data has been pointed out by a number of authors in recent years, including Mayr and Amadon (1951), Beecher (1953), Stresemann (1959), and George and Berger (1966: 229). The New World nine-primaried oscines (Fringillidae and related families) constitute a large segment of oscine forms and encompass a number of interrelated taxonomic problems. The present study includes a largely descriptive account of the myology of the hind limb in a representative family, the I)repanididae, and a subsequent paper will present a similar account of the muscles of the forelimb. Following this, hopefully, a comparative study of the entire New World nine-primaried oscine assemblage will be presented, utilizing an analysis of variations from the basis of comparison provided in the first two studies. The I)repanididae or Hawaiian honeycreepers are endemic to the Hawaiian Islands and have been the subject of much discussion regarding their origin and subsequent evolution. Nothing has been previously written about their appendicular myology. The only detailed anatomical study of this family is an analysis of the feeding mechanism in the genus Loxops (Richards and Bock 1973). Amadon (1950) reviewed the earlier and more limited studies of their structure. In the following account each muscle is described in detail and illustrated in a representative species,