DOCSLIB.ORG

Postcranial Anatomyand Habits of Asian

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Postcranial Anatomyand Habits of Asian An international monograph series of palaeontology and �=---ILS stratigraphy ,.........TA Postcranialanatomy and habits of Asian multituberculate mammals ZofiaKielan- Jaworowska andPetr P. Gambaryan SCANDINAVIAN UNI VERSITYPRESS or.l�Oslo · Copenhagen • Stockholm FOSSILS AND STRATA An international monograph series of palaeontology and stratigraphy Owner Lethaia Foundation, Oslo. Administrative Council: Hans Jørgen Hansen, Copenhagen, David Bruton, Oslo, Christina Franzen, Stockholm, Stefan Bengtson, Uppsala. Editor Stefan Bengtson, Institute of Geosciences - Palaeontology, Norbyvagen 22, S-752 36 Uppsala, Sweden; tel. +46-18 18 27 62; fax +46-1818 27 49; Internet [email protected]. Publisher Scandinavian University Press, P.O. Box 2959, Tøyen, N-0608 Oslo 6, Norway. Programme Fossils and Strata is an international series of monographs and memoirs in palaeontology and stratigraphy, published in cooperation between the Scandinavian countries. It is issued in Numbers with individual pagination. Fossils and Strata forms part ofthe same structured publishingprogramme as the journals Lethaia and Boreas. These two journals are fullyinternational and accept papers within their respective sectors of sciencewithout nationallimitations or preferences. Fossils and Strata, however, is an outlet for more comprehensive systematic and regional monographs emanating primarily fromthe five countries of Norden. Contributions from other countries may also be included if this series is deemed appropriate with regard to distribution and availability. Articles can normally only be accepted if they are heavily subsidized by the national Research Council in their country of origin or by other funds. All income is re-invested in fo rthcoming numbers of the series. Althougharticles in German and French may be accepted, the use ofEnglish is stronglypreferred. An English abstract should always be provided, and non-English articles should have English versions of the figurecaptio ns. Abstracts or summaries in one or more additionallanguages may be added. Many regional or systematic descriptions and revisions contain a nucleus ofresults which are of immediate and general interest in international palaeontology and stratigraphy. It is expected that authors of such papers will to some extent duplicate their publication in the fo rm of an article for a journal, in the firstplace Lethaia or Boreas. Sales Individual numbers and standing subscriptions may be ordered from Scandinavian University Press (address as above). Prices (subject to revision) are listed on the back side of each issue. IPA members generally have a 50% discount on older issues (ask for information fromScandina vian University Press). Allprices exclude postage and handling. LETHAlA An international journal of palaeontology and stratigraphy An international journal of Quaternary research Scandinavian University Press, P.O. Box 2959, Tøyen, N-0608 Oslo 6, Norway Postcranial anatomy and habits of Asian multituberculate mammals ZOFIA KIELAN-JAWO ROWSKA AND PETR P. GAMBARYAN Kielan-Jaworowska, Z. & Gambaryan, P.P. 1994 12 15: Postcranial anatomy and habits of Asian multituberculate mammais. Fossils and Strata, No. 36, pp. 1-92. Oslo. ISSN 0300-9491. ISBN 82- 00-37650-8. Postcranial skeietal elements of six Late Cretaceous taeniolabidoid taxa from the GobiDesert are described, and the postcranial musculature of Kryptobaatar and Nemegtbaatar is reconstructed. A new reconstruction of multituberculate pes is given, showing Mt lI! abducted 30° from the longitudinal axis of the tuber calcanei. The calcaneo--MtV contact and abduction-adduction at the astragalonavicular joint in a horizontal plane, around a vertical axis, are recognized as new multituberculate autapomorphies. Other new, partly plesiomorphic, multituberculate characters are: no transverse foramen in atlas; cervical ribs present at least in some taxa; large iliosacral angle (35-37°); iliosacral contact dorsoventral rather than mediolateral; an incipient supraspinous fo ssa and a peg-like acromion. The deep multituberculate pelvis with femoral adductors originating ventraI to the acetabulum and the large mediolateral diameter of the tibia indicate abduction of the fe mora by 30-60°, while twisting of the humerus is indicative of abducted fo relimbs. Long spinous processes of the lumbar vertebrae, sloping craniodorsally in Asian multituberculates, suggest asymmetrical gait and long jumps, but the short tibia and short Mt lI! suggest short jumps. This inconsistency is due to the abducted limbs, because of which the direct transposition of jump mechanics of mammals with parasagittal limbs does not work for multituberculates. Multituber­ culates possibly had a steeper trajectory ofjump than modem therian mammals. The studied Asian multituberculates do not show adaptations to arborealism. It is suggested that the coracostemal joint disappeared in multituberculates (and independently in therians) as an adaptation to asymmetrical gai!. It is speculated that the competitive inferiority of multituberculates to eutheri­ ans is related to the structure of the pelvis with a ventraI keel, which hindered prolongation of the gestation period, and to abducted limbs that limited their endurance for prolonged running. The analysis of multiturbeculate-therian postcranial synapomorphies does not support the idea that Multituberculata is the sister taxon of Theria. DMammalia, Multituberculata, Anatomy, Creta­ ceous, Asia. Zofia Kielan-Jaworowska, Paleontologisk Museum, Universitetet i Oslo, Sars Gate 1, N--0562Oslo 5, Norway; Petr P. Gambaryan, Zoological Institute, Russian Academy of Sciences, Universitetskaya Naberezhnaya 1, 199164 St. Petersburg, Russia; 27th September, 1993; revised 21st April, 1994. Contents Introduction .............................................................................................. 3 Genus Nemegtbaatar Kielan-Jaworowska, 1974 ................................ 17 Terminology ......................................................................................... 5 Nemegtbaatar gobiensis Kielan-Jaworowska, 1974 ............................. 17 Osteological descriptions .......................................................................... 6 Skull ............................................................................................... 17 Suborder Cimolodonta McKenna, 1975 (new rank); Infraorder Axial skeleton .............................................................. .................. 17 Taeniolabidoidea Sloan & Van Valen, 1965 (new rank); Pectoral girdle and forelimb ............................. ...... ......... ........... 22 Family Eucosmodontidae Jepsen, 1940 ...................................... 6 Pelvis and hind limb ...................................................................... 26 Genus KryptobaatarKielan- Jaworowska, 1970 .................................... 6 Genus Chulsanbaatar Kielan-Jaworowska, 1974 ............................... 30 Kryptobaatardashzevegi Kielan-Jaworowska, 1970 ............................. 6 Chulsanbaatar vulgaris Kielan-J aworowska, 1974 ............................. 30 Skull ................. ................................................................................ 6 Skull ............................................................................................... 31 Axial skeleton ........ ......................... ...................................... ... ...... .. 6 Hyoid apparatus ................. ........................................................... 31 Pectoral girdle (forelimb unknown) ............................................... 7 Axial skeleton ..................... ........................................................... 32 Pelvic girdle and hind limb ............................................................. 7 Pectoral girdle and forelimb ......................................................... 36 Pelvic girdle and hind Iimb ..................... .... ...... ..... ....................... 36 Anatomical comparisons ........................................................................ 57 Family Sloanbaataridae Kielan-Jaworowska, 1974 ............................ 38 Proportions of the body ..................................................................... 57 Genus Sloanbaatar Kielan-Jaworowska, 1970 .................................... 38 Hyoid apparatus ................................................................................. 57 Sloanbaatar mirabilis Kielan-Jaworowska, 1970 ................................ 38 Vertebral column ............................................................................... 57 Axial skeleton ................................................................................ 38 Pectoral girdle and fo relimb .............................................................. 60 Pelvie girdle and hind limb ........................................................... 38 Pelvie girdle and hind limb ................................................................ 62 Family Taeniolabididae Granger & Simpson, 1929 ........................... 39 Functional anatomy ................................................................................ 65 Genus Catopsbaatar Kielan-Jaworowska, 1994 .................................. 39 Reconstruction oflocomotion .......................................................... 65 Catopsbaatar catopsaloides (Kielan-Jaworowska, 1974) ..................... 39 Structure and function of multituberculate pes ................................. 74 Taeniolabidoid, fa
Load more

Recommended publications
  • Dome-Headed, Small-Brained Island Mammal from the Late Cretaceous of Romania
    Dome-headed, small-brained island mammal from the Late Cretaceous of Romania Zoltán Csiki-Savaa,1, Mátyás Vremirb, Jin Mengc, Stephen L. Brusatted, and Mark A. Norellc aLaboratory of Paleontology, Faculty of Geology and Geophysics, University of Bucharest, 010041 Bucharest, Romania; bDepartment of Natural Sciences, Transylvanian Museum Society, 400009 Cluj-Napoca, Romania; cDivision of Paleontology, American Museum of Natural History, New York, NY 10024; and dSchool of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom Edited by Neil H. Shubin, The University of Chicago, Chicago, IL, and approved March 26, 2018 (received for review January 20, 2018) The island effect is a well-known evolutionary phenomenon, in describe the anatomy of kogaionids in detail, include them in a which island-dwelling species isolated in a resource-limited envi- comprehensive phylogenetic analysis, estimate their body sizes, ronment often modify their size, anatomy, and behaviors compared and present a reconstruction of their brain and sense organs. with mainland relatives. This has been well documented in modern This species exhibits several features that we interpret as re- and Cenozoic mammals, but it remains unclear whether older, more lated to its insular habitat, most notably a brain that is sub- primitive Mesozoic mammals responded in similar ways to island stantially reduced in size compared with close relatives and habitats. We describe a reasonably complete and well-preserved skeleton of a kogaionid, an enigmatic radiation of Cretaceous island- mainland contemporaries, demonstrating that some Mesozoic dwelling multituberculate mammals previously represented by frag- mammals were susceptible to the island effect like in more mentary fossils.
    [Show full text]
  • Craniodental Anatomy of a New Late Cretaceous Multituberculate Mammal from Udan Sayr, Mongolia
    University of Louisville ThinkIR: The University of Louisville's Institutional Repository Electronic Theses and Dissertations 8-2014 Craniodental anatomy of a new late cretaceous multituberculate mammal from Udan Sayr, Mongolia. Amir Subhash Sheth University of Louisville Follow this and additional works at: https://ir.library.louisville.edu/etd Part of the Anatomy Commons, and the Medical Neurobiology Commons Recommended Citation Sheth, Amir Subhash, "Craniodental anatomy of a new late cretaceous multituberculate mammal from Udan Sayr, Mongolia." (2014). Electronic Theses and Dissertations. Paper 1317. https://doi.org/10.18297/etd/1317 This Master's Thesis is brought to you for free and open access by ThinkIR: The nivU ersity of Louisville's Institutional Repository. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of ThinkIR: The nivU ersity of Louisville's Institutional Repository. This title appears here courtesy of the author, who has retained all other copyrights. For more information, please contact [email protected]. CRANIODENTAL ANATOMY OF A NEW LATE CRETACEOUS MULTITUBERCULATE MAMMAL FROM UDAN SAYR, MONGOLIA By Amir Subhash Sheth B.A., Centre College, 2010 A Thesis Submitted to the Faculty of the School of Medicine of the University of Louisville in Partial Fulfillment of the Requirements for the Degree of Master of Science Department of Anatomical Sciences and Neurobiology University of Louisville Louisville, Kentucky August 2014 CRANIODENTAL ANATOMY OF A NEW LATE CRETACEOUS MULTITUBERCULATE MAMMAL FROM UDAN SAYR, MONGOLIA By Amir Subhash Sheth B.A., Centre College, 2010 A Thesis Approved on July 18th, 2014 By the Following Thesis Committee: ________________________________ (Guillermo W.
    [Show full text]
  • Mammals from the Mesozoic of Mongolia
    Mammals from the Mesozoic of Mongolia Introduction and Simpson (1926) dcscrihed these as placental (eutherian) insectivores. 'l'he deltathcroids originally Mongolia produces one of the world's most extraordi- included with the insectivores, more recently have narily preserved assemblages of hlesozoic ma~nmals. t)een assigned to the Metatheria (Kielan-Jaworowska Unlike fossils at most Mesozoic sites, Inany of these and Nesov, 1990). For ahout 40 years these were the remains are skulls, and in some cases these are asso- only Mesozoic ~nanimalsknown from Mongolia. ciated with postcranial skeletons. Ry contrast, 'I'he next discoveries in Mongolia were made by the Mesozoic mammals at well-known sites in North Polish-Mongolian Palaeontological Expeditions America and other continents have produced less (1963-1971) initially led by Naydin Dovchin, then by complete material, usually incomplete jaws with den- Rinchen Barsbold on the Mongolian side, and Zofia titions, or isolated teeth. In addition to the rich Kielan-Jaworowska on the Polish side, Kazi~nierz samples of skulls and skeletons representing Late Koualski led the expedition in 1964. Late Cretaceous Cretaceous mam~nals,certain localities in Mongolia ma~nmalswere collected in three Gohi Desert regions: are also known for less well preserved, but important, Bayan Zag (Djadokhta Formation), Nenlegt and remains of Early Cretaceous mammals. The mammals Khulsan in the Nemegt Valley (Baruungoyot from hoth Early and Late Cretaceous intervals have Formation), and llcrmiin 'ISav, south-\vest of the increased our understanding of diversification and Neniegt Valley, in the Red beds of Hermiin 'rsav, morphologic variation in archaic mammals. which have heen regarded as a stratigraphic ecluivalent Potentially this new information has hearing on the of the Baruungoyot Formation (Gradzinslti r't crl., phylogenetic relationships among major branches of 1977).
    [Show full text]
  • The Braincase of Two Late Cretaceous Asian Multituberculates Studied by Serial Sections
    The braincase of two Late Cretaceous Asian multituberculates studied by serial sections J0RN H. HURUM Hurum, J.H. 1998. The braincase of two Late Cretaceous Asian multituberculatesstudied by serial sections. -Acta Palaeontologica Polonica 43, 1, 21-52. The braincase structure of two Late Cretaceous Mongolian djadochtatherian multituber- culates Nemegtbaatar gobiensis and Chulsanbaatar vulgaris from the ?late Campanian of Mongolia is presented based on the two serially sectioned skulls and additional specimens. Reconstructions of the floor of the braincase in both taxa are given. The complete intracranial sphenoid region is reconstructed for the first time in multitubercu- lates. Cavum epiptericum is a separate space with the taenia clino-orbitalis (ossified pila antotica) as the medial wall, anterior lamina of the petrosal and possibly the alisphenoid as the lateral wall, and the basisphenoid, petrosal and possibly alisphenoid ventrally. The fovea hypochiasmatica is shallow, tuberculurn sellae is wide and more raised from the skull base than it is in the genus Pseudobolodon. The dorsal opening of the carotid canal is situated in the fossa hypophyseos. The taenia clino-orbitalis differs from the one described in Pseudobolodon and Lambdopsalis in possessing just one foramen (metoptic foramen). Compared to all extant mammals the braincase in Nemegtbaatar and Chulsan- baatar is primitive in that both the pila antotica and pila metoptica are retained. In both genera the anterior lamina of the petrosal is large with a long anterodorsal process while the alisphenoid is small. A review is given of the cranial anatomy in Nemegtbaatar and Chulsanbaatar. K e y w o r d s : Braincase structure, sphenoid complex, cavum epiptericum,Mammalia, Multituberculata,Djadochtatheria, Cretaceous, Mongolia.
    [Show full text]
  • Multituberculate Mammals from the Cretaceous of Uzbekistan
    Multituberculate mammals from the Cretaceous of Uzbekistan ZOFIA KIELAN- JAWOROWSKA and LEV A. NESSOV Kielan-Jaworowska, 2. & Nessov, L. A. 1992. Multituberculate mammals from the Cretaceous of Uzbelustan. Acta Palaeontologica Polonica 37, 1, 1- 17. The first western Asian multituberculates found in the Bissekty Formation (Co- niacian) of Uzbekistan are described on the basis of a lower premolar (p4), a fragment of a lower incisor, an edentulous dentary, a proximal part of the humerus and a proximal part of the femur. Uzbekbaatar kizylkumensis gen. et sp. n. is defined as having a low and arcuate p4. possibly without a posterobuccal cusp; it presumably had two lower premolars, as inferred from the presence of a triangular concavity at the upper part of the anterior wall of p4, and p3 less reduced in relation to p4 than in non-specialized Taeniolabidoidea and Ptilodontoidea. Uzbek- baatar is placed in the Cimolodonta without indicating family and infraorder. It might have originated from the Plagiaulacinae or Eobaatarinae. Key words : Multituberculata, Marnmalia, Cretaceous, Coniacian, Uzbekistan. Zofia Kielan-Jaworowska. Paleontologisk Museum, Universitetet i Oslo, Sars Gate 1, N-0562 Oslo, Norway. flec A. Hecoc, kf~cmumym3exnoiL Kopbl, Ca~~m-nemep6ypzc~uiiYnueepcumem, 199 034 Ca~~m-l7emep6ypz,Poccun (Lev A. Nessov, Institute of the Earth Crust, Sankt-Peters- burg University, 199 034 St. Petersburg. Russla]. Introduction The Multituberculata is the first mammalian order to have adapted to herbivorous niches, although many may have been omnivorous (Krause 1982). Known from the Late Triassic to the Early Oligocene (Hahn & Hahn 1983), this order of mammals was dominant throughout the Mesozoic in most of the local faunas studied.
    [Show full text]
  • The Earliest Mammal of the European Paleocene: the Multituberculate Hainina
    J. Paleont., 74(4), 2000, pp. 701–711 Copyright ᭧ 2000, The Paleontological Society 0022-3360/00/0074-0701$03.00 THE EARLIEST MAMMAL OF THE EUROPEAN PALEOCENE: THE MULTITUBERCULATE HAININA P. PELA´ EZ-CAMPOMANES,1 N. LO´ PEZ-MARTI´NEZ,2 M.A. A´ LVAREZ-SIERRA,2 R. DAAMS3 1Department Paleobiologı´a,Museo Nacional de Ciencias Naturales, Gutie´rrez Abascal 2, 28006 Madrid, Spain, Ͻ[email protected]Ͼ, and 2Department-UEI Paleontologı´a, Facultad C. Geolo´gicas-Instit. Geologı´a Econo´mica,Universidad Complutense-CSIC, 28040 Madrid, Spain ABSTRACT—A new species of multituberculate mammal, Hainina pyrenaica n. sp. is described from Fontllonga-3 (Tremp Basin, Southern Pyrenees, Spain), correlated to the later part of chron C29r just above the K/T boundary. This taxon represents the earliest European Tertiary mammal recovered so far, and is related to other Hainina species from the European Paleocene. A revision of the species of Hainina allows recognition of a new species, H. vianeyae n. sp. from the Late Paleocene of Cernay (France). The genus is included in the family Kogaionidae Ra˜dulescu and Samson, 1996 from the Late Cretaceous of Romania on the basis of unique dental characters. The Kogaionidae had a peculiar masticatory system with a large, blade-like lower p4, similar to that of advanced Ptilodon- toidea, but occluding against two small upper premolars, interpreted as P4 and P5, instead of a large upper P4. The endemic European Kogaionidae derive from an Early Cretaceous group with five premolars, and evolved during the Late Cretaceous and Paleocene. The genus Hainina represents a European multituberculate family that survived the K/T boundary mass extinction event.
    [Show full text]
  • Masticatory Musculature of Asian Taeniolabidoid Multituberculate Mammals
    Masticatory musculature of Asian taeniolabidoid multituberculate mammals PETR P. GAMBARYAN & ZOFIA KIELAN-JAWOROWSKA* Gambaryan, P.P. & Kielan-Jaworowska, 2. 1995. Masticatory musculature of Asian taeniolabidoid multituberculate mammals. Acta Palaeontologica Polonica 40, 1, 45-108. The backward chewing stroke in multituberculates (unique for mammals) resulted in a more anterior insertion of the masticatory muscles than in any other mammal group, including rodents. Multituberculates differ from tritylodontids in details of the masticatory musculature, but share with them the backward masticatory power stroke and retractory horizontal components of the resultant force of all the masticatory muscles (protractory in Theria). The Taeniolabididae differ from the Eucosmodontidae in having a more powerful masticatory musculature, expressed by the higher zygomatic arch with relatively larger anterior and middle zygomatic ridges and higher coronoid process. It is speculated that the bicuspid, or pointed upper incisors, and semi-procumbent, pointed lower ones, characteristic of non- taeniolabidoid mdtitliberculates were used for picking-up and killing insects or other prey. In relation to the backward power stroke the low position of the condylar process was advantageous for most multituberculates. In extreme cases (Sloanbaataridae and Taeniolabididae), the adaptation for crushing hard seeds, worked against the benefit of the low position of the condylar process and a high condylar process developed. Five new multituberculate autapomorphies are rec- ognized: anterior and intermediate zygomatic ridges: glenoid fossa large, flat and sloping backwards (forwards in rodents), arranged anterolateral and standing out from the braincase; semicircular posterior margin of the dentary with condylar process forming at least a part of it; anterior position of the coronoid process; and anterior position of the masseteric fossa.
    [Show full text]
  • New Specimens of the Multituberculate Mammal Sphenopsalis from China: Implications for Phylogeny and Biology of Taeniolabidoids
    New specimens of the multituberculate mammal Sphenopsalis from China: Implications for phylogeny and biology of taeniolabidoids FANG-YUAN MAO, YUAN-QING WANG, and JIN MENG Mao, F.-Y., Wang, Y.-Q., and Meng, J. 2016. New specimens of the multituberculate mammal Sphenopsalis from China: Implications for phylogeny and biology of taeniolabidoids. Acta Palaeontologica Polonica 61 (2): 429–454. Multituberculates are the most diverse and best known group of Mesozoic mammals; they also persisted into the Paleogene and became extinct in the Eocene, possibly outcompeted by rodents that have similar morphological and pre- sumably ecological adaptations. Among the Paleogene multituberculates, those that have the largest body sizes belong to taeniolabidoids, which contain several derived species from North America and Asia and some species with uncertain taxonomic positions. Of the known taeniolabidoids, the poorest known taxon is Sphenopsalis nobilis from Mongolia and Inner Mongolia, China, represented previously by a few isolated teeth. Its relationship with other multituberculates thus has remained unclear. Here we report new specimens of Sphenopsalis nobilis collected from the upper Paleocene of the Erlian Basin, Inner Mongolia, China, during a multi-year field effort beginning in 2000. These new specimens document substantial parts of the dental, partial cranial and postcranial morphologies of Sphenopsalis, including the upper and lower incisors, partial premolars, complete upper and lower molars, a partial rostrum, fragments of the skull roof, middle ear cavity, a partial scapula, and partial limb bones. With the new specimens we are able to present a detailed description of Sphenopsalis, comparisons among relevant taeniolabidoids, and brief phylogenetic analyses based on a dataset consisting of 43 taxa and 102 characters.
    [Show full text]
  • The First Late Cretaceous Mammal from Inner Mongolia (P
    bulletin de l'institut royal des sciences naturelles de belgique sciences de la terre. 71-supp.: 29-50. 2001 bulletin van het koninklijk belgisch instituut voor natuurwetenschappen aardwetenschappen, 71-supp.: 29-50, 2001 A new species ofKryptobaatar (Multituberculata): the first Late Cretaceous mammal from Inner Mongolia (P. R. China)1 by Thierry SMITH, Dian-Yong GUO & Yan SUN SMITH, T., GUO, D.-Y. & SUN, Y„ 2001 - A new species of Introduction Kryptobaatar (Multituberculata): the first Late Cretaceous mammal from Inner Mongolia (P. R. China), Bulletin de l'Institut royal des Many Cretaceous mammal species were described from Sciences naturelles de Belgique, : Sciences de la Terre, Supplement 71 the 29-50, 9 pis., 8 figs., 2 tables; Bruxelles-Brussel, December 15, 2001. Mongolian part of the Gobi desert (see Kielan- -ISSN 0374-6291 Jaworowska et al., 2000, for an overview), most of them collected from the Djadokhta Formation at Bayn Dzak Abstract (American-Mongolian expéditions in 1920s, see Simpson, 1925, 1928; Polish-Mongolian expéditions in Multituberculates are the best represented mammals of the Late Cretaceous 1963 to 1971, see Kielan-Jaworowska, 1970, 1974) and in Asia and most of them are from Outer Mongolia. The djadochtatheri- from Ukhaa Tolgod (American-Mongolian expéditions oidean multituberculate Kryptobaatar mandahuensis n. sp. is described on since the 1990s, see Rougier et al., 1997; Wible & the basis of two skulls from the Upper Cretaceous locality of Bayan Mandahu (Inner Mongolia, People's Republic of China). The main
    [Show full text]
  • Mammal Disparity Decreases During the Cretaceous Angiosperm Radiation
    Mammal disparity decreases during the Cretaceous angiosperm radiation David M. Grossnickle1 and P. David Polly2 1Department of Geological Sciences, and 2Departments of Geological Sciences, Biology, and Anthropology, rspb.royalsocietypublishing.org Indiana University, Bloomington, IN 47405, USA Fossil discoveries over the past 30 years have radically transformed tra- ditional views of Mesozoic mammal evolution. In addition, recent research provides a more detailed account of the Cretaceous diversification of flower- Research ing plants. Here, we examine patterns of morphological disparity and functional morphology associated with diet in early mammals. Two ana- Cite this article: Grossnickle DM, Polly PD. lyses were performed: (i) an examination of diversity based on functional 2013 Mammal disparity decreases during dental type rather than higher-level taxonomy, and (ii) a morphometric analysis of jaws, which made use of modern analogues, to assess changes the Cretaceous angiosperm radiation. Proc R in mammalian morphological and dietary disparity. Results demonstrate a Soc B 280: 20132110. decline in diversity of molar types during the mid-Cretaceous as abundances http://dx.doi.org/10.1098/rspb.2013.2110 of triconodonts, symmetrodonts, docodonts and eupantotherians dimin- ished. Multituberculates experience a turnover in functional molar types during the mid-Cretaceous and a shift towards plant-dominated diets during the late Late Cretaceous. Although therians undergo a taxonomic Received: 13 August 2013 expansion coinciding with the angiosperm radiation, they display small Accepted: 12 September 2013 body sizes and a low level of morphological disparity, suggesting an evol- utionary shift favouring small insectivores. It is concluded that during the mid-Cretaceous, the period of rapid angiosperm radiation, mammals experi- enced both a decrease in morphological disparity and a functional shift in dietary morphology that were probably related to changing ecosystems.
    [Show full text]
  • Dome-Headed, Small-Brained Island Mammal from the Late Cretaceous of Romania
    Dome-headed, small-brained island mammal from the Late Cretaceous of Romania Zoltán Csiki-Savaa,1, Mátyás Vremirb, Jin Mengc, Stephen L. Brusatted, and Mark A. Norellc aLaboratory of Paleontology, Faculty of Geology and Geophysics, University of Bucharest, 010041 Bucharest, Romania; bDepartment of Natural Sciences, Transylvanian Museum Society, 400009 Cluj-Napoca, Romania; cDivision of Paleontology, American Museum of Natural History, New York, NY 10024; and dSchool of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom Edited by Neil H. Shubin, The University of Chicago, Chicago, IL, and approved March 26, 2018 (received for review January 20, 2018) The island effect is a well-known evolutionary phenomenon, in describe the anatomy of kogaionids in detail, include them in a which island-dwelling species isolated in a resource-limited envi- comprehensive phylogenetic analysis, estimate their body sizes, ronment often modify their size, anatomy, and behaviors compared and present a reconstruction of their brain and sense organs. with mainland relatives. This has been well documented in modern This species exhibits several features that we interpret as re- and Cenozoic mammals, but it remains unclear whether older, more lated to its insular habitat, most notably a brain that is sub- primitive Mesozoic mammals responded in similar ways to island stantially reduced in size compared with close relatives and habitats. We describe a reasonably complete and well-preserved skeleton of a kogaionid, an enigmatic radiation of Cretaceous island- mainland contemporaries, demonstrating that some Mesozoic dwelling multituberculate mammals previously represented by frag- mammals were susceptible to the island effect like in more mentary fossils.
    [Show full text]
  • The Middle Ear in Multituberculate Mammals
    The middle ear in multituberculate mammals J0RN H. HURUM, ROBERT PRESLEY and ZOFIA KIELAN-JAWOROWSKA Hurum, J.H., Presley, R., & Kielan-Jaworowska, 2. 1996. The middle ear in multituberculate mammals. Acta Paheontologica Polonica 41, 3, 253-275. The ear ossicles, preserved in skulls of a tiny Late Cretaceous multituberculate Chulsanbaatar vulgaris from Mongolia are arranged as in modem mammals. This makes the idea of an independent origin of the multituberculates from other mammals unlikely. We report the finding of ear ossicles in Mesozoic multituber- culates. Three almost complete incudes and two fragments of malleus are de- scribed and compared with those reported in the Paleocene Lambdopsalis and in non-multituberculate mammals. In these Late Cretaceous multituberculates lat- eral expansion of the braincase is associated with the presence of sinuses and development of extensive masticatory musculature, but not by the expansion of the vestibule, which is moderately developed. It is argued that because of the lateral expansion of the multituberculate braincase, the promontorium is ar- ranged slightly more obliquely with respect to the sagittal plane than in other mammals and the fenestra vestibuli faces anterolaterally, rather than laterally. This results in a corresponding alteration in orientation of the stapes. The epitympanic recess is situated more anteriorly with respect to the fenestra vestibuli than in other mammals. The recess is deep, and the incus must therefore be oriented somewhat vertically. The incus is roughly A-shaped, with crus breve subparallel to the axis of vibration of the malleus. This axis, approximately connecting the anterior process of the malleus and the crus breve of the incus, lies at 45-55" to the sagittal plane in Chulsanbaatar.
    [Show full text]