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UNIVERSITY OF KANSAS PUBLICATIONS MUSEUM OF NATURAL HISTORY

Volume 12, No. 12, pp. 521-551, 22 figs. October 25, 1963

Jaw Musculature Of the Mourning and White-winged Doves

ROBERT L. MERZ

UNIVERSITY OF KANSAS LAWRENCE 1963

UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Theodore H. Eaton, Jr.

Volume 12, No. 12, pp. 521-551, 22 figs. Published October 25, 1963

UNIVERSITY OF KANSAS Lawrence, Kansas

PRINTED BY JEAN M. NEIBARGER, STATE PRINTER TOPEKA, KANSAS 1963

29-7865

Jaw Musculature Of the Mourning and White-winged Doves

ROBERT L. MERZ

For some time many investigators have thought that the genus Zenaida, which includes the White-winged and Zenaida doves, and the genus Zenaidura, which includes the Mourning, Eared, and Socorro doves (Peters, 1937:83-88), are closely related, perhaps more closely than is indicated by separating the several species into two genera. It is the purpose of this paper to report investigations on the musculature of the jaw of doves with the hope that, together with the results of other studies, the relationships of the genera Zenaida and Zenaidura can be elucidated.

METHODS AND MATERIALS

In order to determine in each species the normal pattern of musculature of the jaws, heads of 13 specimens of doves were dissected (all material is in the Museum of Natural History of The University of Kansas): White-winged Doves (Zenaida asiatica), 40323, 40324, 40328, 40392, 40393; Zenaida Doves (Z. aurita), 40399, 40400; Mourning Doves (Zenaidura macroura), 40326, 40394, 40395, 40396, 40397, 40398.

Thirty-seven skulls from the collection of the Museum of Natural History of The University of Kansas and two skulls from the United States National Museum were measured. The measurements are on file in the Library of The University of Kansas in a dissertation deposited there by me in 1963 in partial fulfillment of requirements for the degree of Master of Arts in Zoology. Specimens used were: White-winged Doves, KU 19141, 19142, 19143, 19144, 19145, 19146, 19147, 23138, 23139, 24337, 24339, 24341, 23592, 23593, 24340, 31025, 31276; Mourning Doves, KU 14018, 14781, 15347, 15533, 15547, 15550, 15662, 15778, 15872, 16466, 17782, 17786, 17788, 17795, 19153, 19242, 20321, 21669, 22394, 22715; Eared Doves (Zenaidura auriculata), USNM 227496, 318381. Additionally, the skulls of the Zenaida Doves mentioned above were measured. All measurements were made with a dial caliper and read to tenths of a millimeter.

ACKNOWLEDGMENTS

My appreciation is extended to Professor Richard F. Johnston, who advised me during the course of this study, and to Professors A. Byron Leonard and Theodore H. Eaton for critically reading the manuscript.

I would like also to acknowledge the assistance of Dr. Robert M. Mengel and Mr. Jon C. Barlow for suggestions on procedure, and Mr. William C. Stanley, who contributed specimens of Mourning Doves for study. Mr. Thomas H. Swearingen offered considerable advice on production of drawings and Professor E. Raymond Hall suggested the proper layout of the same and gave editorial assistance otherwise, as also did Professor Johnston.

MYOLOGY

The jaw musculature of doves is not an imposing system. The eating habits impose no considerable stress on the muscles; the mandibles are not used for crushing seeds, spearing, drilling, gaping, or probing as are the mandibles of many other kinds of birds. Doves use their mandibles to procure loose seeds and grains, which constitute the major part of their diet (Leopold, 1943; Kiel and Harris, 1956: 377; Knappen, 1938; Jackson, 1941), and to gather twigs for construction of nests. Both activities require but limited gripping action of mandibles. The crushing habit of a bird such as the Hawfinch (Coccothraustes coccothraustes), on the other hand, involves extremely powerful gripping (see, for example, Sims, 1955); the contrast is apparent in the development of the jaw musculature in the two types. Consequently, it is not surprising to find a relatively weak muscle mass in the jaw of doves, and because the musculature is weak there are few pronounced osseous fossae, cristae and tubercles. As a result, the bones, in addition to being small in absolute size, are relatively weaker when compared to skulls of birds having more distinctive feeding habits which require more powerful musculature.

The jaw muscles of the species dissected for this study are, in gross form, nearly identical from one species to another. Thus, a description of the pertinent myology of each species is unnecessary; one basic description is hereby furnished, with remarks on the variability observed between the species.

The terminology adopted by me for the jaw musculature is in boldfaced italic type. Synonyms are in italic type and are the names most often used by several other writers.

~M. pterygoideus ventralis:~ part of Mm. pterygoidei, Gadow, 1891:323-325, table 26, figs. 1, 2, 3 and 4, and table 27, fig. 3--part of M. pterygoideus internus, Shufeldt, 1890:20, figs. 3, 5, 6, 7 and 11--part of M. adductor mandibulae internus, Edgeworth, 1935:58, figs. 605c and 607--part of M. pterygoideus anterior, Adams, 1919:101, pl. 8, figs. 2 and 3.

~M. pterygoideus dorsalis:~ part of Mm. pterygoidei, Gadow, 1891:323-325, table 26, fig. 7 and table 27, figs. 1 and 3--part of M. pterygoideus internus, Shufeldt, 1890:20--part of M. adductor mandibulae internus, Edgeworth, 1935:58, fig. 605c--? part of M. pterygoideus anterior, Adams, 1919:101, pl. 8, figs. 2 and 3.

~M. adductor mandibulae externus:~ a) ~pars superficialis:~ parts 1 and 2 of M. temporalis, Gadow, 1891:320-321--part of M. temporal, Shufeldt, 1890:16, figs. 5 and 7--part of M. adductor mandibulae externus, Edgeworth, 1935:58-60--M. capiti-mandibularis medius and profundus, Adams, 1919:101, pl. 8, fig. 1.