{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,26]],"date-time":"2026-09-26T13:53:07Z","timestamp":1790430787265,"version":"4.1.0"},"reference-count":44,"publisher":"The Royal Society","issue":"926","license":[{"start":{"date-parts":[[1976,2,26]],"date-time":"1976-02-26T00:00:00Z","timestamp":194140800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/royalsociety.org\/journals\/ethics-policies\/data-sharing-mining\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[1976,2,26]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Abundant but dissociated postcranial materials assignable to Eozostrodon (from Pont Alun quarry, Glamorgan, Wales) are described together with the associated, partial skeletons of Megazostrodon rudnerae and Erythrotherium parringtoni (from the Red Beds of southern Africa). The postcranial skeletons of these Triassic triconodonts are evaluated in both comparative and functional terms. Triassic triconodonts inherited from cynodonts specializations in the atlas-axis complex (e.g. double occipital condyles, a dens, reduction of the atlanto-axial zygapophyses) which permitted extensive cranial flexion-extension at the atlanto-occipital joint and rotation at the atlanto-axial joint. Marked differentiation of the major vertebral regions appears for the first time among mammals. In Megazostrodon, post-axis cervical vertebrae bear relatively narrow laminae and pedicles, broadly spaced zygapophyses, and rod-like, posteriorly recurved spinous processes; this pattern appears to be basic to mammals, and is retained among many later, generalized groups. The structure of the cervical vertebrae reveals that a cervico-thoracic flexure and an ascending posture of the neck were present. The large size of cervical vertebral foramina is evidence of a marked enlargement of the spinal cord at levels corresponding to the origin of the brachial plexus; this relationship may be interpreted as evidence of a greater neuromuscular control of the forelimb and a freedom of neck movement typical of mammals. An \u2018anticlinal\u2019 region in the thoracolumbar vertebral series has been identified in Eozostrodon; this musculoskeletal specialization is related to axial flexion and extension characteristic of the posture and locomotor movements in mammals. The sacrum consists of at least two (and possibly three) vertebrae. The tail is moderately long and incorporates approximately twelve vertebrae. The shoulder girdle of Eozostrodon is little modified from the basic cynodont pattern; a T-shaped interclavicle, the lack of a supraspinous fossa, and the presence of both coracoids are features retained by monotremes. Both the coracoid and the scapula participate in the narrow, semi-lunar glenoid. The humero-ulnar joint is condylar, rather than trochlear, a condition retained by monotremes and other non-therian groups. The pelvic girdle represents a fully mammalian grade of organization; there is no evidence of epipubic bones. The limb skeleton, and particularly the joints, show various features consistent with an interpretation of well-developed mobility. The claw structure is suggestive of prehensility and an ability to climb. The hallux, at least, was probably somewhat divergent, and its joint structures indicate that abduction and extension (independent of the other digits) were possible. Triassic mammals as now known were all small, insectivorous forms; Megazostrodon was approximately 10 cm in head-body length, probably weighed between 20 and 30 g, and was proportioned similarly to medium-sized shrews (e.g. Suncus murinus, Blarina blarina). A skeletal reconstruction of a Triassic triconodont is depicted, and an interpretation of their habits is presented.<\/jats:p>","DOI":"10.1098\/rstb.1976.0022","type":"journal-article","created":{"date-parts":[[2006,12,18]],"date-time":"2006-12-18T17:23:53Z","timestamp":1166462633000},"page":"387-431","source":"Crossref","is-referenced-by-count":140,"title":["The postcranial skeletons of the Triassic mammals\n                    <i>Eozostrodon, Megazostrodon<\/i>\n                    and\n                    <i>Erythrotherium<\/i>"],"prefix":"10.1098","volume":"273","author":[{"given":"F. A.","family":"Jenkins, Jr","sequence":"first","affiliation":[{"name":"Department of Biology and Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, U. S. A."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francis Rex","family":"Parrington","sequence":"additional","affiliation":[{"name":"University Museum of Zoology, Cambridge, England"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"175","reference":[{"key":"p_2","doi-asserted-by":"crossref","unstructured":"Cartmill M. 1974 Pads and claws in arboreal locomotion. In Primate locomotion (ed. F. A. Jenkins Jr) pp. 45-83. New York: Academic Press.","DOI":"10.1016\/B978-0-12-384050-9.50007-6"},{"key":"p_3","first-page":"441","article-title":"A preliminary description of a new mammal from the Upper Triassic of South Africa. Proc. zool","volume":"142","author":"Crompton A. W.","year":"1964","journal-title":"Soc. Lond."},{"key":"p_4","first-page":"137","article-title":"The enigma of the evolution of mammals","volume":"18","author":"Crompton A. W.","year":"1968","journal-title":"Optima"},{"key":"p_5","first-page":"399","article-title":"The dentitions and relationships of the Southern African Triassic mammals, Erythrotherium parringtoni and Megazostrodon rudnerae","volume":"24","author":"Crompton A. W.","year":"1974","journal-title":"Hist. Geol."},{"key":"p_6","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-185X.1968.tb00966.x"},{"issue":"1","key":"p_7","first-page":"7","article-title":"Notes on a new tritylodontid from the Cave Sandstone of South Africa. Navors. nas","volume":"2","author":"Fourie S.","year":"1962","journal-title":"Mus. Bloemfontein"},{"key":"p_8","first-page":"601","article-title":"A revision of the Tertiary","volume":"56","author":"Granger W.","year":"1929","journal-title":"Hist."},{"key":"p_9","first-page":"211","article-title":"A revision of the extensor muscles of the forearm in tetrapods","volume":"73","author":"Haines R. W.","year":"1939","journal-title":"J. Anat."},{"key":"p_10","first-page":"270","article-title":"The tetrapod knee joint","volume":"76","author":"Haines R. W.","year":"1942","journal-title":"J. Anat."},{"key":"p_11","doi-asserted-by":"publisher","DOI":"10.2307\/2257405"},{"key":"p_12","doi-asserted-by":"publisher","DOI":"10.1002\/ar.1091640205"},{"key":"p_13","doi-asserted-by":"publisher","DOI":"10.1126\/science.168.3938.1473"},{"key":"p_14","first-page":"1","article-title":"a The postcranial skeleton of African cynodonts. Bull. Peabody Mus. nat","volume":"36","author":"Jenkins F. A., Jr.","year":"1971","journal-title":"Hist."},{"key":"p_15","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7998.1971.tb02189.x"},{"key":"p_16","first-page":"281","article-title":"The functional anatomy and evolution of the mammalian humero-ulnar articulation. Am.J","volume":"137","author":"Jenkins F. A., Jr.","year":"1973","journal-title":"Anat."},{"key":"p_17","doi-asserted-by":"crossref","unstructured":"Jenkins F. A. Jr. 1974a Tree shrew locomotion and the origins of primate arborealism. In Primate locomotion (ed. F. A. Jenkins Jr) pp. 85-115. New York: Academic Press.","DOI":"10.1016\/B978-0-12-384050-9.50008-8"},{"key":"p_18","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.1051440105"},{"key":"p_19","doi-asserted-by":"publisher","DOI":"10.1086\/282714"},{"key":"p_20","doi-asserted-by":"crossref","unstructured":"Jerison H. J. 1973 Evolution of the brain and intelligence. New York: Academic Press.","DOI":"10.1016\/B978-0-12-385250-2.50018-3"},{"key":"p_21","doi-asserted-by":"crossref","unstructured":"Kappers G. U . A. Huber G. C. & Crosby E. C. 1936 The comparative anatomy of the nervous system of vertebrates including man vol. 1. New York: MacMillan.","DOI":"10.1097\/00005053-193612000-00041"},{"issue":"1533","key":"p_22","first-page":"31","article-title":"New Mesozoic mammals from South Wales. Proc. geol","author":"Kermack K. A.","year":"1956","journal-title":"Soc."},{"key":"p_23","first-page":"144","article-title":"The first mammals","volume":"20","author":"Kermack K. A.","year":"1959","journal-title":"Discovery. Lond."},{"key":"p_24","doi-asserted-by":"publisher","DOI":"10.1111\/j.1096-3642.1973.tb00786.x"},{"key":"p_25","doi-asserted-by":"publisher","DOI":"10.1038\/2221091a0"},{"key":"p_26","first-page":"729","article-title":"The geology of the fissure-filling `Holwell 2 '; the age-determination of the mammalian teeth therein; and a report on the technique employed when collecting the teeth of Eozostrodon and Microcleptidae. Proc. zool","volume":"116","author":"Kiihne W. G.","year":"1946","journal-title":"Soc. Lond."},{"key":"p_27","doi-asserted-by":"publisher","DOI":"10.1038\/166696a0"},{"key":"p_28","unstructured":"Kiihne W. G. 1956 The Liassic therapsid Oligokyphus. London: British Museum (Natural History)."},{"key":"p_29","doi-asserted-by":"publisher","DOI":"10.1007\/BF02989032"},{"key":"p_30","doi-asserted-by":"publisher","DOI":"10.1016\/B978-1-4831-9977-1.50010-9"},{"issue":"2066","key":"p_31","first-page":"1","article-title":"On the shoulder girdle of the mammalian subclass","author":"McKenna M. C.","year":"1961","journal-title":"Allotheria. Am. Mus. Novit."},{"key":"p_32","doi-asserted-by":"publisher","DOI":"10.2307\/1933776"},{"issue":"8","key":"p_33","first-page":"140","article-title":"On two mammalian teeth from the Lower Rhaetic of","volume":"11","author":"Parrington F. R.","year":"1941","journal-title":"Hist."},{"key":"p_34","first-page":"707","article-title":"On a collection of Rhaetic mammalian teeth. Proc. zool","volume":"116","author":"Parrington F. R.","year":"1946","journal-title":"Soc. Lond."},{"key":"p_35","first-page":"285","article-title":"The evolution of the mammalian femur. Proc. zool","volume":"137","author":"Parrington F. R.","year":"1961","journal-title":"Soc. Lond."},{"key":"p_36","first-page":"165","article-title":"The origins of mammals","volume":"24","author":"Parrington F. R.","year":"1967","journal-title":"Advmt Sci. Lond."},{"key":"p_37","doi-asserted-by":"publisher","DOI":"10.1098\/rstb.1971.0055"},{"key":"p_38","unstructured":"Peterson J. A. 1975 Adaptations for arboreal locomotion in the shoulder of Chamaeleo. J. Morph (in the Press)."},{"key":"p_39","unstructured":"Riek E. F. 1970 Fossil history. In The insects of Australia pp. 168-186. Sponsored by the Division of Entomology C.S.I.R.O . Canberra. Melbourne: Melbourne University Press."},{"issue":"1","key":"p_40","first-page":"10","article-title":"The importance of insects in the evolution of land vertebrates. (In Russian.) Paleont","author":"Rohdendorf B. B.","year":"1970","journal-title":"Zhur."},{"key":"p_41","unstructured":"Schmidt-Nielsen K. 1975 Animal physiology. London: Cambridge University Press."},{"key":"p_42","unstructured":"Simpson G. G. 1928 A catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum. London: British Museum (Natural History)."},{"key":"p_43","doi-asserted-by":"crossref","unstructured":"Simpson G. G. 1929 American Mesozoic Mammalia. New Haven: Yale University Press.","DOI":"10.5962\/bhl.title.5717"},{"key":"p_44","first-page":"1","article-title":"Comparative biologic-anatomical investigations on the vertebral column and spinal musculature of mammals. Verb. K. ned","volume":"42","author":"Slijper E. J.","year":"1946","journal-title":"Acad. Wet. ( Tweede Sectie)"},{"key":"p_45","doi-asserted-by":"publisher","DOI":"10.1126\/science.178.4065.1096"}],"container-title":["Philosophical Transactions of the Royal Society of London. 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