Fort Hays State University FHSU Scholars Repository Master's Theses Graduate School Summer 1947 A Descriptive Analysis of The Musculature And Osseous Systems of The Kangaroo Rat, Dipodomys Ordii Virgil Mathis Fort Hays Kansas State College Follow this and additional works at: https://scholars.fhsu.edu/theses Part of the Biology Commons Recommended Citation Mathis, Virgil, "A Descriptive Analysis of The Musculature And Osseous Systems of The Kangaroo Rat, Dipodomys Ordii" (1947). Master's Theses. 394. https://scholars.fhsu.edu/theses/394 This Thesis is brought to you for free and open access by the Graduate School at FHSU Scholars Repository. It has been accepted for inclusion in Master's Theses by an authorized administrator of FHSU Scholars Repository. A DESCRIPTIVE ANALYSIS OF THE MUSCULATURE AND OSSEOUS SYSTEMS OF THE KANGAROO RAT, DIPODOMYS OR.DU being A thesis presented to the Graduate Faculty of the Fort Hays Kansas State College in partial fulfillment of the requirements for the Degree of Master of Science by Virgil Mathis, B, S , in Ed. No rthwest Missouri State Teachers College J..-1 n A / • Date 1. ~) Jq 7 Approved / IC'....,X---'V · . (l ½:f-' ~l ,..~ Major Professor i TABLE OF CONTENTS PAGE UJTRODUCTION . • • 1 Related Studies 3 MYOLOGY ••• 4 Muscles of the Head • • • • • • • 4 Superficial Facial Musculature . 4 Masticatory Musculature • • • • • • • • • • • • • • • • • 8 Interramal Musculature • • • • • • • • • • • • • • • • • • 10 Muscles of the Tongue • • • 11 Muscles of the Anterior Limb • 11 Muscles of the Shoulder Girdle • 11 Muscles of the Upper Arm • 13 Muscles of the Forearm 15 Mus cles of the Body ••• 19 Muscles of the Neck • • • • • • • • • • • • • • • • • • 20 Superficial muscles ••••• 20 Supra- and infrahyoid muscles ••• 20 Deep lateral and subvertebral muscles 22 Muscles of the Trunk •• 23 Muscles of the thorax . 23 Muscles of the abdomen • • • • • • • • • • • • • • • 27 Lumbar muscle ••• 28 Muscles of the back • 19 Perineal musculature ••••••••• , • 4l ii PAGE Muscles of the Posterior Limb. 42 Muscles of the Hip. 42 Iliopsoas group . 43 Gluteal group • 43 Obturator group . 45 Muscles of the Thigh • 46 Muscles of the Leg. 51 OSTEOLOGY 56 Skull 56 Trunk 58 Cervical Vertebrae. 58 Thoracic Vertebrae. 58 1umbar Vertebrae 59 Sacral Vertebrae. 59 Caudal Vertebrae. 59 Sternum. 60 Costae. 60 Extremities • 60 Clavicle • 60 Scapula 61 Humerus 61 Radius and Ulna. 61 Innominate 62 Femur •• 62 iii PAGE Tibia and Fibula 62 CONCLUSION • 63 BIBLIOGRAPHY 65 1 INTRODUCTION The kangaroo rats constitute the only genus, Dipodomys, of the subfamily Heteromyinae, now ·extant. There is fossil evidence of two other genera which are now extinct. The kangaroo rat, Dipodom.ys ordii richardsoni, is one of the common rodents of western Kansas . According to Hibbard (3, p. 76), "Its range extends northeastward along the Kansas river into Riley County." These animals are easily distinguished from other rodents by their long tail, long hind legs and feet, small hands, fur lined ex- ternal cheek pouches, am their saltating method of locomotion. These rodents are seldom seen by the casual observer, being strictly nocturnal ·and very timid. A good way to observe their activity is to drive by automobile through a pasture at night. It is not un- common to see numbers of them bounding along in front of the head- lights. Not often are the kangaroo rats considered of much economic importance. They build their shallow burrows in gravelly or more fre- quently sandy soil. They seem to thrive best around old sand pits, sand dunes or valley borders. They are chiefly inhabitants of desert country, but may thrive in out of the way places in semi-arid regions. Apparently almost all kinds of seeds are utilized as food by these animals. Woodhouse has reported finding in their cheek pouches great- numbers of seeds of wild sunflowers (Helianthus and Ximenesia) 2 and also hard beans of a legume (Parosela). Goldman has observed them gathering seeds of the common mesquite (Prosopis glandulosa). In an examination of the pockets Goldman found in various specimens the seeds of the rag bush (Gaertheris acanthicarpa), ripening seeds of the desert willow (Chilopsis linearis), seeds of tumble weed (Atriplex expansa), capsules of the common purslane (Portulaca oleracea), seeds of cr~sote0 bush (Covillea tridentata), arrl others. (Bailey, 1, p. 268) From the appearance of their burrow entrances, they must be rather neat •housekeepers". These openings are often strewn with seed husks which have been thrown out from their dens. This writer found the seed hus~s of the sandbur (Cenchrus paudflorus), and the seed pods of the Rocky Mountain bee plant (Cleome serrulata) literally form- ing a carpet of refuse at some of the burrow entrances. One other highly important adaptation of t hese animals to their environment is their ability to live indefinitely without water. The animal is capable of utilizing enough metabolic water to carry on all life processes. Pearse (6, p. 100) has stated that, "Physiology is the key- stone of ecology"; Howell (5, p. 1) has mentioned that, "The internal anatomy of all but a few mammals has been woefully neglected"; and Hall (2, p. 7) 'believes, 11 ••• , that taxonomic characters of consider- able value will be found 'in the musculature when more forms have been studied. 11 These needs form the stimulus for this research. This being an anatomical problem, and not an ecological one, the remainder of the paper shall deal with the animal solely from the 3 point of view of anatomy. The specimens collected for this study were caught in live traps baited with oatmeal. Eight specimens were caught in an old abandoned sand pit twelve miles south of Hays, Kansas. Six of these, four males arxi two females, were measured for total length, length of tail, and length of pes, and preserved in a ten per cent solution of formalin for study. These six specimens were dissected. No muscles requiring microscopy were considered. Not in every case were all the muscles compared but wherever variation was found or any degree of doubt persisted it was checked in all six specimens. An attempt is made to describe the muscular system with extreme thoroughness. The ossesous system is not nearly as intricate and is treated in much less detail. The writer regrets that this subject lends itself only to the technical language of anatomy. Related Studies There has been little work done on the internal anatomy of all but a few of our small mammals. Anatomists have thoroughly treated the cat am the rabbit but have failed to continue with many of our common rodents. Howell (5, p. 1-225) has made a comparative anatomical study, in minute detail, of three common North American rodents, Homodontom.ys, Neotoma, and Teonoma. His work has been used as a basic guide in this research. The same author also made a similar study of the three genera, 4 Allactaga, Dipodom..ys,and Scirtopoda (Howell, 4, p. 377-536). It should be borne in mind that all quotations from the last mentioned works deal with a different species from that of this re- search. Similar studies, but not of rodents, have been made by Hall (2, P• 7-38) of three mustelid mammals, Mephitis, Spilogale, and Martes. In another study Hall has given an account of the muscular · anatomy of the .American badger. Much is yet needed to be done in the field of anatomy befor e it can be said to be adequately explored. MYOLOGY There is slight individual variation in the musculature of all animals, no two animals being exactly alike. It is i mpossible to define some muscles with exactness, especially those arising or inserting within fascia, or muscles which are partly or wholly in- separable from each other. Specimens that have been kept in preser- vative often give a false impression of the true nat ure of t he muscle, because never do the muscles "set" precisely the same. The muscles which are about to follow are grouped f or the sake of convenience only, and do not necessarily constitute group relat- ionship. Muscles of the Head Superficial Facial Musculature 5 Levator labii arises from a considerable area upon the rostrum, mainly the premaxilla. Insertion is into the extreme dorso-cranial fold of the pouch and the mystacial pad. Dilator naris has its origin mostly mediad but deep to the levator labii. Two long tiny tendons develop, the dorsal one insert- ing just dorso-caudad of the nostril, the other extenru.ng to the extreme tip between the nostrils. Orbicularis oculi arises on the maxilla immediately laterad to the suture of the frontal bone. Its fibers circurnvent the eye. The muscle functions as a sphincter, closing the eye. A greater amount of fibers being on the lower lid would indicate it does most of the move- ment in closing the eye. Orbicularis oris has strong tendinous fibers inserting into the margin of the lower lip. Attempts to follow these fibers through the tenuous fascia were unsatisfactory. Depressor nasalis consists of short stout fibers extending between the ventral center of the nostrils and the extreme cranial portion of the upper lip·. Maxillonasolabialis arises from the maxillary deep to the ectal head of the masseter major. Several long tendons extend to insertion upon the ventro-lateral portion of the nostril. Other tendons emanating from what appears to be this same muscle, but is in all likelihood a separate slip, insert into the upper lip. Orbiculoris sacculi lies beneath the skin but external to the pouch at its opening, or in other words in the groove formed by the 6 infolding of the pouch. It appears as a partial continuation of the- ventral sphincter colli profundus, but most of the fibers arise from the pouch i t self, inserting into the mystacial pad.