DOCSLIB.ORG

A Swimming Mammaliaform from the Middle Jurassic And

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Swimming Mammaliaform from the Middle Jurassic And RESEARCH ARTICLES chromatin entry site activities of TREs are 13. G. Rank, M. Prestel, R. Paro, Mol. Cell. Biol. 22, 8026 32. M. J. O’Neill, Hum. Mol. Genet. 14 Spec No 1:R113 functionally separated. Cumulatively, our (2002). (2004). 14. E. Bae, V. C. Calhoun, M. Levine, E. B. Lewis, 33. S. W.-L. Chan et al., Science 303, 1336 (2004). results support a model in which RNAs R. A. Drewell, Proc. Natl. Acad. Sci. U S A. 99, 16847 34. S. I. Grewal, J. C. Rice, Curr. Opin. Cell Biol. 16, 230 transcribed from the TREs of Ubx are retained (2002). (2004). at TREs through DNA-RNA interactions and 15. H. D. Lipshitz, D. A. Peattie, D. S. Hogness, Genes Dev. 1, 35. M. Christmann, M. T. Tomicic, W. P. Roos, B. Kaina, provide a RNA scaffold that is bound by 307 (1987). Toxicology 193, 3 (2003). 16. J. Dejardin et al., Nature 434, 533 (2005). 36. Y. Chen, G. Varani, FEBS J. 272, 2088 (2005). Ash1. 17. T. Rozovskaia et al., Mol. Cell. Biol. 19, 6441 (1999). 37. F. H. Allain, P. W. Howe, D. Neuhaus, G. Varani, EMBO J. 18. C. H. Martin et al., Proc. Natl. Acad. Sci. USA 92, 8398 16, 5764 (1997). References and Notes (1995). 38. V. H. Meller, B. P. Rattner, EMBO J. 21, 1084 (2002). 1. R. Jaenisch, A. Bird, Nat. Genet. 33 (suppl.), 245 19. See supporting material on Science Online. 39. We thank J. A. Diaz-Pendon, E. Poon, and M. Rubalcava (2003). 20. A. Akhtar, Curr. Opin. Genet. Dev. 13, 161 (2003). for support with RACE, tissue culture, and disc prepara- 2. B. M. Turner, Cell 111, 285 (2002). 21. A. Wutz, Bioessays 25, 434 (2003). tion, and members of the Sauer lab for helpful comments 3. V. Orlando, Cell 112, 599 (2003). 22. E. Heard, Curr. Opin. Cell Biol. 16, 247 (2004). that improved the manuscript. F.S. thanks S. Angle for 4. L. Ringrose, R. Paro, Annu. Rev. Genet. 38, 413 23. M. A. Matzke, J. A. Birchler, Nat. Rev. Genet. 6,24 support. Supported by Deutsche Forschungsgemeinschaft (2004). (2005). (DFG) research fellowship SA1010/1-1 (T.S.-E.), a 5. A. Breiling, V. Orlando, Nat. Struct. Biol. 9, 894 (2002). 24. W. A. Krajewski, T. Nakamura, A. Mazo, E. Canaani, Mol. DFG/Transregio-5 grant (E.K.), and NIH grant GM073776 6. P. B. Becker, W. Horz, Annu. Rev. Biochem. 71, 247 Cell. Biol. 25, 1891 (2005). and VolkswagenStiftung grant I/79-725 (F.S.). (2002). 25. S. R. Albright, R. Tjian, Gene 242, 1 (2000). 7. T. Jenuwein, C. D. Allis, Science 293, 1074 (2001). 26. T. Maile, S. Kwoczynski, R. J. Katzenberger, 8. R. Cao, Y. Zhang, Curr. Opin. Genet. Dev. 2, 155 D. A. Wassarman, F. Sauer, Science 304, 1010 (2004). (2004). 27. H. Kawasaki, K. Taira, Curr. Opin. Mol. Ther. 7, 125 Supporting Online Material www.sciencemag.org/cgi/content/full/311/5764/1118/DC1 9. C. Beisel, A. Imhof, J. Greene, E. Kremmer, F. Sauer, (2005). Materials and Methods Nature 419, 857 (2002). 28. C. B. Phelps, A. H. Brand, Methods 14, 367 (1998). Figs. S1 to S16 10. N. Tripoulas, D. LaJeunesse, J. Gildea, A. Shearn, Genetics 29. E. J. Sontheimer, Nat. Rev. Mol. Cell Biol. 6, 127 (2005). Tables S1 to S3 143, 913 (1996). 30. V. Schranke, R. Allshire, Curr. Opin. Gen. Gev. 14, 174 References 11. D. LaJeunesse, A. Shearn, Mech. Dev. 53, 123 (1995). (2004). 12. S. Schmitt, M. Prestel, R. Paro, Genes Dev. 19, 697 31. A. Verdel et al., Science 303, 672 (2004); published 20 July 2005; accepted 23 January 2006 (2005). online 2 January 2004 (10.1126/science.1093686). 10.1126/science.1117705 Q425 mm) with incomplete cranium (pre- A Swimming Mammaliaform from the served length Q60 mm) but well-preserved mandibles and lower dentition (incisors 4, Middle Jurassic and Ecomorphological canine 1, premolars 5, molars 6). Lower molars 3 to 6 have the diagnostic characteristics of docodontans (Fig. 2): anteriorly placed and Diversification of Early Mammals enlarged lingual cusp g, triangulated crests 1,3 2,1 3 2 formed by cusps a-c and a-g, and two partially Qiang Ji, Zhe-Xi Luo, * Chong-Xi Yuan, Alan R. Tabrum enclosed basins formed respectively by cusps a, b, and g, and by cusps a, c, and d (9–12). As in A docodontan mammaliaform from the Middle Jurassic of China possesses swimming all docodontans, the molars were capable of and burrowing skeletal adaptations and some dental features for aquatic feeding. It is both shearing by the triangulated crests and the most primitive taxon in the mammalian lineage known to have fur and has a broad, grinding between the anterior (‘‘pseudotalonid’’) flattened, partly scaly tail analogous to that of modern beavers. We infer that docodontans basin and the transversely widened upper molars were semiaquatic, convergent to the modern platypus and many Cenozoic placentals. (9–12). Castorocauda is distinctive from other This fossil demonstrates that some mammaliaforms, or proximal relatives to modern mammals, docodontans in having mediolaterally com- developed diverse locomotory and feeding adaptations and were ecomorphologically different pressed crowns of molars 1 and 2, each with from the majority of generalized small terrestrial Mesozoic mammalian insectivores. five cusps in straight alignment (23, 24); pri- mary cusp a and posterior cusps c and d are he Middle Jurassic mammalian diver- several taxa are known from the Middle slightly recurved (Fig. 2). These ‘‘triconodont- sification gave rise to several emergent Jurassic (1, 9–13). Here, we report on a large like’’ anterior molars are plesiomorphic for Tclades: basal eutriconodontans, amphi- docodontan mammaliaform that has some mammaliaforms (6–8) but nonetheless distinc- theriid cladotherians, the basal mammalian dental features for feeding on aquatic inverte- tive among docodontans. They are convergent to lineage of shuotheriids, and basal australos- brates and small vertebrates, plus specialized those of placental mesonychians and Eocene phenidans (1–5). These new clades of crown skeletal and soft-tissue features for swimming whales (25). This type of molar with recurved Mammalia coexisted with several mamma- and burrowing. cusps in alignment is hypothesized to be a spe- liaform lineages (the proximal relatives to Description and comparison. Castorocauda cialization for feeding on fish and aquatic modern mammals) (1, 6–8). Docodontans are lutrasimilis, gen. et sp. nov. (14), is from the invertebrates by functional analogy to the teeth a Mesozoic mammaliaform lineage that have Middle Jurassic Jiulongshan Formation, dated of modern pinniped carnivores such as seals. specialized molars for omnivorous feeding; to be approximately 164 million years ago Castorocauda is preserved with intact middle (15–17). The fauna includes pterosaurs (17, 18), ear bones (Fig. 2) on the mandible, including the 1 Department of Earth Science, Nanjing University, Nanjing a coelurosaurian dinosaur (19), lissamphibians articular (malleus), the surangular, and the 200017, China. 2Carnegie Museum of Natural History, Pittsburgh, PA 15213, USA. 3Chinese Academy of Geolog- (20), abundant fossil insects (21), and the angular (ectotympanic). The middle ear bones ical Sciences, Beijing 100037, China. conchostracan Euestheria (22). The holotype in anatomical association with the mandible *To whom correspondence should be addressed. E-mail: of C. lutrasimilis (Fig. 1) is represented by a corroborate a previous interpretation of the mid- [email protected] partial skeleton (preserved rostrum-tail length dle ear in docodontans (26). A concavity on the www.sciencemag.org SCIENCE VOL 311 24 FEBRUARY 2006 1123 RESEARCH ARTICLES Fig. 1. Holotype of Castorocauda lutrasimilis [Jinzhou Museum of Paleon- tology (JZMP) 04-117]. (A)Photograph of the holotype. (B) Osteological struc- tures and preserved soft-tissue features. (C)ReconstructionofCastorocauda lutrasimilis as a swimming and burrow- ing mammaliaform. Abbreviations: as, as- tragalus; ca, caudal vertebrae; cn, ento-, meso-, and ecto-cuneiforms; co, coro- noid process of dentary; cp, carpals; cs, calcaneus; ec, ectepicondyle and supi- nator shelf (humerus); ef, entepicondyle foramen; ep?, probable epipubis; is, ischium; J, jugal; L1-6, lumbar ribs 1 to 6; m, molars; mb, manubrium of malleus; mp, metacarpals; mx, maxilla; px, premaxilla; ra, radius; rc, radial condyle; S1-2, sacrals 1 and 2; sp, extratarsal (‘‘poisonous’’) spur; t4-t14 (preserved ribs through thoracic 17); uc, ulnar condyle; ul, ulna. posterior aspect of the mandibular angle ac- Fig. 2. Dentition and commodates the ectotympanic (angular). The mandible of Castorocauda posterior position of the ectotympanic concav- lutrasimilis (JZMP04-117). ity on the mandibular angle in docodontans is (A)Labialviewoflower different from and more derived than that in the molars 1 to 6. (B)Lin- mammaliaforms Sinoconodon and Morganu- gual view of lower molars codon, in which the ectotympanic concavity 1to6.(C)Crownviewof is on the medial aspect of the mandibular angle lower molars 3 to 6. (D) (6, 7). The manubrium of the malleus (retro- Cusp pattern [cusp desig- nation from (11, 12)]. (E) articular process of the articular) is anteriorly Middle ear bones. (F) curved and long in comparison with the Reconstructed mandible short manubrium of Morganucodon and and middle ear bones Sinoconodon (6, 7, 27). The proportion of (lateral view). c, canine; the malleus manubrium is similar to that of m, molars. extant monotremes, although slightly more robust than in the latter. Castorocauda is sim- ilar to crown Mammalia and more derived than Sinoconodon, Morganucodon,andallpre- mammaliaform cynodonts (27)inpreservedmid- dle ear features. Our analyses, including new characters of Castorocauda, corroborate that docodontans are a mammaliaform clade, less derived than Hadrocodium but more derived than Sinoco- nodon and Morganucodon (1, 8, 26, 28, 29). Among docodontans, Castorocauda is close- ly related to the Middle Jurassic Krusatodon and Simpsonodon of England (9–11), sug- gesting interchange between faunas of the Eurasian landmasses during the Middle Ju- rassic time.
Load more

Recommended publications
  • Reptile-Like Physiology in Early Jurassic Stem-Mammals
    bioRxiv preprint doi: https://doi.org/10.1101/785360; this version posted October 10, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Title: Reptile-like physiology in Early Jurassic stem-mammals Authors: Elis Newham1*, Pamela G. Gill2,3*, Philippa Brewer3, Michael J. Benton2, Vincent Fernandez4,5, Neil J. Gostling6, David Haberthür7, Jukka Jernvall8, Tuomas Kankanpää9, Aki 5 Kallonen10, Charles Navarro2, Alexandra Pacureanu5, Berit Zeller-Plumhoff11, Kelly Richards12, Kate Robson-Brown13, Philipp Schneider14, Heikki Suhonen10, Paul Tafforeau5, Katherine Williams14, & Ian J. Corfe8*. Affiliations: 10 1School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK. 2School of Earth Sciences, University of Bristol, Bristol, UK. 3Earth Science Department, The Natural History Museum, London, UK. 4Core Research Laboratories, The Natural History Museum, London, UK. 5European Synchrotron Radiation Facility, Grenoble, France. 15 6School of Biological Sciences, University of Southampton, Southampton, UK. 7Institute of Anatomy, University of Bern, Bern, Switzerland. 8Institute of Biotechnology, University of Helsinki, Helsinki, Finland. 9Department of Agricultural Sciences, University of Helsinki, Helsinki, Finland. 10Department of Physics, University of Helsinki, Helsinki, Finland. 20 11Helmholtz-Zentrum Geesthacht, Zentrum für Material-und Küstenforschung GmbH Germany. 12Oxford University Museum of Natural History, Oxford, OX1 3PW, UK. 1 bioRxiv preprint doi: https://doi.org/10.1101/785360; this version posted October 10, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 13Department of Anthropology and Archaeology, University of Bristol, Bristol, UK. 14Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK.
    [Show full text]
  • The Mammary Gland and Its Origin During Synapsid Evolution
    P1: GMX Journal of Mammary Gland Biology and Neoplasia (JMGBN) pp749-jmgbn-460568 January 9, 2003 17:51 Style file version Nov. 07, 2000 Journal of Mammary Gland Biology and Neoplasia, Vol. 7, No. 3, July 2002 (C 2002) The Mammary Gland and Its Origin During Synapsid Evolution Olav T. Oftedal1 Lactation appears to be an ancient reproductive trait that predates the origin of mammals. The synapsid branch of the amniote tree that separated from other taxa in the Pennsylva- nian (>310 million years ago) evolved a glandular rather than scaled integument. Repeated radiations of synapsids produced a gradual accrual of mammalian features. The mammary gland apparently derives from an ancestral apocrine-like gland that was associated with hair follicles. This association is retained by monotreme mammary glands and is evident as ves- tigial mammary hair during early ontogenetic development of marsupials. The dense cluster of mammo-pilo-sebaceous units that open onto a nipple-less mammary patch in monotremes may reflect a structure that evolved to provide moisture and other constituents to permeable eggs. Mammary patch secretions were coopted to provide nutrients to hatchlings, but some constituents including lactose may have been secreted by ancestral apocrine-like glands in early synapsids. Advanced Triassic therapsids, such as cynodonts, almost certainly secreted complex, nutrient-rich milk, allowing a progressive decline in egg size and an increasingly altricial state of the young at hatching. This is indicated by the very small body size, presence of epipubic bones, and limited tooth replacement in advanced cynodonts and early mammali- aforms. Nipples that arose from the mammary patch rendered mammary hairs obsolete, while placental structures have allowed lactation to be truncated in living eutherians.
    [Show full text]
  • Mammalian Origins Major Groups of Synapsida
    Mammalogy 4764 9/16/2009 Chapter 4 “Reptile” Mammalian Origins Early mammal Carnivore Amniota Herbivore Feldhamer Table 4.1 Savage and Long 1986 Major Fig. 3.2, Vaughn, Fig. 4.1, Feldhamer groups Mammalian Origins of Dimetrodon Overview Synapsida Synapsids Pelycosaurs and Therapsids First Mammals Mesozoic Era appear Feldhamer Fig. 4.2 Cenozoic Era radiate Savage and Long 1986 Pelycosaur Skull, jaw musculature, and teeth Cynodontia -- Advanced, predaceous therapsids Pelycosaur Scymnognathus Cynognathus Therapsid Early Cynodont Derived Therapsid/Mammal Primitive Late Cynodont Fig. 3.2, Vaughn Thrinaxodon Fig 4.3 & 4, Feldhamer 1 Mammalogy 4764 9/16/2009 Skeletal transition Extinction of Cynodonts Possibly competition from dinosaurs Pelycosaur Early Cynodonts were dog-size, last surviving were squirrel sized Fig. 4.15 Mammals that survived while Cynodonts went extinct (contemporary) were mouse-sized. Cynodont Thrinaxodon Modern Mammal Fig. 3.5, Vaughn Fig. 4.16c, Early Cynodont Early mammals Changes in land masses Feldhamer 4.11 200 - 250 million years ago Derived characters: Dentary/squamosal jaw articulation Diphyodont dentition 200 MYA 180 MYA Mammary glands Secondary palate Early Mid- Viviparity (loss of eggshell) When? Jurassic Jurassic 65 MYA 135 MYA Early Early Cretaceous Cenozoic Feldhamer 4.5, 4.9 Skull and teeth of mammals 2 Mammalogy 4764 9/16/2009 Teeth and Dentition of Mammals Teeth Heterodont teeth with different functions Differentiated on the basis of function, resulting in increased One of the major keys efficiency acquiring and digesting food. to success of mammals Teeth occur in 3 bones of skull: Teeth of mammals are premaxilla, maxilla, dentary extremely variable with different diets -- more than other taxa Feldhamer et al.
    [Show full text]
  • Width Measured at the Level of Anterior Squamosal/Parietal Suture
    Fig. 5. (A) Scaling of brain vault size (width measured at the level of anterior squamosal/parietal suture) relative to skull size (measured at the distance between the left versus right temporomandibular joints). This shows that allometry of small size of Hadrocodium, by itself, is not sufficient to account for its very large braincase. Had-rocodium's brain vault is larger (wider) than expected for the crown-group mammals with similar skull width from the allometrical regression. By contrast, all contemporaneous mammaliaforms (triangles: Sinoconodon, Morganucodon, and Haldanodon) with the postdentary trough and meckelian groove have smaller (narrower) brain vaults than those living mammal taxa (and Hadrocodium) of comparable skull size. The brain vault is narrower in nonmammaliaform cynodonts (squares: Chaliminia, Massetoganthus, Probelesodon, Probainognathus, and Yunnanodon) than in mammaliaform stem taxa and much narrower than expected for crown group mammals of similar size. The allometric equation (natural logarithmic scale) for the brain vault width (Y) to the skull width at the level of TMJ (X) for species in the mammalian crown groups (circles: 37 living and 8 fossil species): Y =0.98X -0.31 (R2 – 0.715). Data from cynodonts, mammaliaforms, and Hadrocodium are added second arily for comparison with the regression of extant and fossil species of mammalian crown group. (B) Estimated body-size distributions of mammaliaform insectivores in the Early Jurassic Lufeng fauna [following method of Gingerich (50)]. The estimated 2-g body mass of Hadrocodium is in strong contrast to its contemporary mammaliaforms of the Late Triassic and Early Jurassic, such as Sinconodon (from ~13 to ~517 g, based on skull length from 22 to 62 mm) and Morganucodon (from 27 to 89 g, based on skull length from 27 to 38 mm).
    [Show full text]
  • The Mesozoic Era Alvarez, W.(1997)
    Alles Introductory Biology: Illustrated Lecture Presentations Instructor David L. Alles Western Washington University ----------------------- Part Three: The Integration of Biological Knowledge Vertebrate Evolution in the Late Paleozoic and Mesozoic Eras ----------------------- Vertebrate Evolution in the Late Paleozoic and Mesozoic • Amphibians to Reptiles Internal Fertilization, the Amniotic Egg, and a Water-Tight Skin • The Adaptive Radiation of Reptiles from Scales to Hair and Feathers • Therapsids to Mammals • Dinosaurs to Birds Ectothermy to Endothermy The Evolution of Reptiles The Phanerozoic Eon 444 365 251 Paleozoic Era 542 m.y.a. 488 416 360 299 Camb. Ordov. Sil. Devo. Carbon. Perm. Cambrian Pikaia Fish Fish First First Explosion w/o jaws w/ jaws Amphibians Reptiles 210 65 Mesozoic Era 251 200 180 150 145 Triassic Jurassic Cretaceous First First First T. rex Dinosaurs Mammals Birds Cenozoic Era Last Ice Age 65 56 34 23 5 1.8 0.01 Paleo. Eocene Oligo. Miocene Plio. Ple. Present Early Primate First New First First Modern Cantius World Monkeys Apes Hominins Humans A modern Amphibian—the toad A modern day Reptile—a skink, note the finely outlined scales. A Comparison of Amphibian and Reptile Reproduction The oldest known reptile is Hylonomus lyelli dating to ~ 320 m.y.a.. The earliest or stem reptiles radiated into therapsids leading to mammals, and archosaurs leading to all the other reptile groups including the thecodontians, ancestors of the dinosaurs. Dimetrodon, a Mammal-like Reptile of the Early Permian Dicynodonts were a group of therapsids of the late Permian. Web Reference http://www.museums.org.za/sam/resource/palaeo/cluver/index.html Therapsids experienced an adaptive radiation during the Permian, but suffered heavy extinctions during the end Permian mass extinction.
    [Show full text]
  • Femur of a Morganucodontid Mammal from the Middle Jurassic of Central Russia
    Femur of a morganucodontid mammal from the Middle Jurassic of Central Russia PETR P. GAMBARYAN and ALEXANDER 0.AVERIANOV Gambaryan, P.P. & Averianov, A.O. 2001. Femur of a morganucodontid mammal from the Middle Jurassic of Central Russia. -Acta Palaeontologica Polonica 46,1,99-112. We describe a nearly complete mammalian femur from the Middle Jurassic (upper Bathonian) from Peski quarry, situated some 100 km south east of Moscow, central Rus- sia. It is similar to the femora of Morganucodontidae in having a globular femoral head, separated from the greater trochanter and reflected dorsally, fovea capitis present, both trochanters triangular and located on the same plane, distal end flat, mediolaterally expanded, and somewhat bent ventrally, and in the shape and proportions of distal condyles. It is referred to as Morganucodontidae gen. et sp. indet. It is the first representa- tive of this group of mammals in Eastern Europe from the third Mesozoic mammal local- ity discovered in Russia. Exquisite preservation of the bone surface allowed us to recon- struct partial hind limb musculature. We reconstruct m. iliopsoas as inserting on the ridge, which starts at the lesser trochanter and extends along the medial femoral margin for more than half of the femur length. On this basis we conclude that the mode of loco- motion of the Peski morganucodontid was similar to that of modern echidnas. During the propulsive phase the femur did not retract and the step elongation was provided by pronation of the femur. Key words : Mammalia, Morganucodontidae, femur, anatomy, locomotion, Jurassic, Russia. Petr P. Gambaryan [[email protected]] and Alexander 0.
    [Show full text]
  • I Found a Baby Mammal Now What?
    I Found a Baby Mammal Now What? To Find a wildlife Is baby animal hurt or sick rehabilitator in your area, (bleeding, shivering, vomiting; contact No was attacked by cat/dog?) •Your state wildlife agency •Humane Society Yes Can you find the nest or den? •Audubon Society Is it intact? •Wild bird stores •City Animal control officer •Veterinarian (wildlife/exotic) Yes No Call a wildlife rehabilitator. •Coast Guard or Marine Patrol •US Fish & Wildlife Service Place baby in Place baby in •Wildlife Rehab Info Directory: nest/den. shallow box close to (wildliferehab.virtualave.net) where it was found. Keep it warm but out of Unable to reach a wildlife rehabilitator? sun. Call your state wildlife agency or a wildlife Veterinarian. A baby’s Watch for mother for best chance 4-6 hours. for survival Stay completely out of sight. is its mother Mothers won’t return if any people or pets are present. If you are unable to reach any of the Above, see instructions on back of this page: “How to rescue Baby Mammals” Did the Mother return? Yes No Leave the area. Call a wildlife Baby is OK. rehabilitator. If you find a seal pup or fawn: If you find baby bunnies: •Mothers normally leave their babies to feed. •If their nest has been damaged it can be repaired. Look for a •If baby looks cold, hungry, diseased, or shallow depression lined with grass/fur. Place babies in nest with confused, or if dogs, other animals, or people light layers at grass to hide them. Leave the area, or the mother threaten its safety, call a wildlife rehabilitator won’t return.
    [Show full text]
  • A Non-Mammaliaform Cynodont from the Upper Triassic of South Africa: a Therapsid Lazarus Taxon?
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Wits Institutional Repository on DSPACE A non-mammaliaform cynodont from the Upper Triassic of South Africa: a therapsid Lazarus taxon? Fernando Abdala1*, Ross Damiani2, Adam Yates1 & Johann Neveling3 1Bernard Price Institute for Palaeontological Research, School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS, 2050 South Africa 2Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, D-70191, Stuttgart, Germany 3Council for Geoscience, Private Bag X112, Pretoria, 0001 South Africa Received 20 January 2006. Accepted 10 January 2007 The tetrapod record of the ‘Stormberg Group’, including the Lower Elliot Formation, in the South African Karoo is widely dominated by archosaurian reptiles, contrasting with the therapsid dominion of the subjacent Beaufort Group. The only therapsids represented by skeletal remains in the Upper Triassic Lower Elliot Formation are the large traversodontid cynodont Scalenodontoides macrodontes and the recently described tritheledontid cynodont Elliotherium kersteni. Here we present a fragmentary lower jaw that provides evidence of a third type of cynodont for the Upper Triassic of South Africa. The fossil is tentatively assigned to the Diademodontidae. The latter representative of this family is known from the Late Anisian, and its tentative record in the Norian Lower Elliot Formation, if confirmed, will represent a case of Lazarus taxon. Thus, Diademodontidae apparently disappeared from the fossil record by the end of the Anisian and then reappeared in the Norian of South Africa, a stratigraphic interval of some 21 million years. This new cynodont record, together with the recently described Tritheledontidae, show that cynodonts are now the second most diverse tetrapod group in the Lower Elliot fauna.
    [Show full text]
  • The History of the World in Comics
    TABLE OF CONTENTS Earth Is Born 6 THE CENOZOIC 43 On the Prairies 44 THE PRECAMBRIAN 7 In the Trees 45 The Cradle of Life 8 Little Horses 46 The First Cells 9 The New Giants 47 A World of Microbes 10 Walking Whales 48 Upheavals 1 1 Swimming Whales 49 The First Faunas 12 Trumpeters 50 Island America 5 1 THE PALEOZOIC 13 The Rise of the Ruminants 52 The Explosion of Life 14 The Giraffe’s Neck 53 Pincers of the Sea 15 Teeth in the Sea 54 Conquering the Continents 16 Teeth on Land 55 Jaws of the Sea 17 The Hominids 56 The March of the Fish 18 On Four Feet 19 THE QUATERNARY 57 The Great Forest 20 The Ice Ages 58 Born on Land 2 1 Megafauna of the Tundra 59 The First Giants 22 The Reunion of the Americas 60 Reptiles Unlike the Others 23 An Island Continent 6 1 The Great Extinction 24 The First Humans 62 Conquering the World 63 THE MESOZOIC 25 Mini-Elephants of the Islands 64 The Time of the Crocs 26 Cro-Magnon 65 The First Dinosaurs 27 The Great Warming 66 The First Mammals 28 The Pterosaurs 29 THE TIME OF THE HUMANS 67 The Jurassic Sea 30 The Agricultural Revolution 68 Sea Monsters 3 1 Cows, Pigs, Poultry 69 The Ornithischians 32 The Industrial Revolution 70 The Epic of the Stegosaurs 33 The Sixth Extinction 7 1 The Sauropods 34 Living Planet 72 The Theropods 35 Life in the Universe 73 Dinosaurs with Feathers 36 Wings and Teeth 37 Geologic Time Scale 74 Rivals of the Dinosaurs 38 Fur Balls 39 Glossary 76 Flowers for the Dinosaurs 40 The End of a World 4 1 Index 78 Night of the Cretaceous 42 by Jean-Baptiste de Panafieu • illustrated by Adrienne Barman NEW YORK Triassic: 252 to 201 million years ago THE FIRST DINOSAURS Marasuchus feeds on Some of the archosaurs insects and small animals.
    [Show full text]
  • Mammal Evolution
    Mammal Evolution Geology 331 Paleontology Triassic synapsid reptiles: Therapsids or mammal-like reptiles. Note the sprawling posture. Mammal with Upright Posture From Synapsids to Mammals, a well documented transition series Carl Buell Prothero, 2007 Synapsid Teeth, less specialized Mammal Teeth, more specialized Prothero, 2007 Yanoconodon, Lower Cretaceous of China Yanoconodon, Lower Cretaceous of China, retains ear bones attached to the inside lower jaw Morganucodon Yanoconodon = articular of = quadrate of Human Ear Bones, or lower reptile upper reptile Auditory Ossicles jaw jaw Cochlea Mammals have a bony secondary palate Primary Palate Reptiles have a soft Secondary Palate secondary palate Reduction of digit bones from Hand and Foot of Permian Synapsid 2-3-4-5-3 in synapsid Seymouria ancestors to 2-3-3-3-3 in mammals Human Hand and Foot Class Mammalia - Late Triassic to Recent Superorder Tricodonta - Late Triassic to Late Cretaceous Superorder Multituberculata - Late Jurassic to Early Oligocene Superorder Monotremata - Early Cretaceous to Recent Superorder Metatheria (Marsupials) - Late Cretaceous to Recent Superorder Eutheria (Placentals) - Late Cretaceous to Recent Evolution of Mammalian Superorders Multituberculates Metatheria Eutheria (Marsupials) (Placentals) Tricodonts Monotremes . Live Birth Extinct: . .. Mammary Glands? Mammals in the Age of Dinosaurs – a nocturnal life style Hadrocodium, a lower Jurassic mammal with a “large” brain (6 mm brain case in an 8 mm skull) Were larger brains adaptive for a greater sense of smell? Big Brains and Early Mammals July 14, 2011 The Academic Minute http://www.insidehighered.com/audio/academic_pulse/big_brains_and_early_mammals Lower Cretaceous mammal from China Jawbones of a Cretaceous marsupial from Mongolia Mammal fossil from the Cretaceous of Mongolia Reconstructed Cretaceous Mammal Early Cretaceous mammal ate small dinosaurs Repenomamus robustus fed on psittacosaurs.
    [Show full text]
  • Osteohistology of Late Triassic Prozostrodontian Cynodonts from Brazil
    Osteohistology of Late Triassic prozostrodontian cynodonts from Brazil Jennifer Botha-Brink1,2, Marina Bento Soares3 and Agustín G. Martinelli3 1 Department of Karoo Palaeontology, National Museum, Bloemfontein, South Africa 2 Department of Zoology and Entomology, University of the Free State, Bloemfontein, South Africa 3 Departamento de Paleontologia e Estratigrafia, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil ABSTRACT The Prozostrodontia includes a group of Late Triassic-Early Cretaceous eucynodonts plus the clade Mammaliaformes, in which Mammalia is nested. Analysing their growth patterns is thus important for understanding the evolution of mammalian life histories. Obtaining material for osteohistological analysis is difficult due to the rare and delicate nature of most of the prozostrodontian taxa, much of which comprises mostly of crania or sometimes even only teeth. Here we present a rare opportunity to observe the osteohistology of several postcranial elements of the basal prozostrodontid Prozostrodon brasiliensis, the tritheledontid Irajatherium hernandezi, and the brasilodontids Brasilodon quadrangularis and Brasilitherium riograndensis from the Late Triassic of Brazil (Santa Maria Supersequence). Prozostrodon and Irajatherium reveal similar growth patterns of rapid early growth with annual interruptions later in ontogeny. These interruptions are associated with wide zones of slow growing bone tissue. Brasilodon and Brasilitherium exhibit a mixture of woven-fibered bone tissue and slower growing parallel-fibered and lamellar bone. The slower growing bone tissues are present even during early ontogeny. The relatively slower growth in Brasilodon and Brasilitherium may be related to their small body size compared to Prozostrodon and Irajatherium. These brasilodontids also exhibit osteohistological similarities with the Late Triassic/Early Jurassic mammaliaform Morganucodon and the Late Cretaceous multituberculate mammals Kryptobaatar and Nemegtbaatar.
    [Show full text]
  • Early Cretaceous Amphilestid ('Triconodont') Mammals from Mongolia
    Early Cretaceous amphilestid ('triconodont') mammals from Mongolia ZOFIAKIELAN-JAWOROWSKA and DEMBERLYIN DASHZEVEG Kielan-Jaworowską Z. &Daslueveg, D. 1998. Early Cretaceous amphilestid (.tricono- dont') mammals from Mongotia. - Acta Pal.aeontol.ogicaPolonica,43,3, 413438. Asmall collection of ?Aptianor ?Albian amphilestid('triconodont') mammals consisting of incomplete dentaries and maxillae with teeth, from the Khoboor localiĘ Guchin Us counĘ in Mongolia, is described. Grchinodon Troftmov' 1978 is regarded a junior subjective synonym of GobiconodonTroftmov, 1978. Heavier wear of the molariforms M3 andM4than of themore anteriorone-M2 in Gobiconodonborissiaki gives indirect evidence formolariformreplacement in this taxon. The interlocking mechanismbetween lower molariforms n Gobiconodon is of the pattern seen in Kuchneotherium and Ttnodon. The ińterlocking mechanism and the type of occlusion ally Amphilestidae with Kuehneotheriidae, from which they differ in having lower molariforms with main cusps aligned and the dentary-squamosal jaw joint (double jaw joint in Kuehneotheńdae). The main cusps in upper molariforms M3-M5 of Gobiconodon, however, show incipient tńangular arrangement. The paper gives some support to Mills' idea on the therian affinities of the Amphilestidae, although it cannot be excluded that the characters that unite the two groups developed in parallel. Because of scanty material and arnbiguĘ we assign the Amphilestidae to order incertae sedis. Key words : Mammali4 .triconodonts', Amphilestidae, Kuehneotheriidae, Early Cretaceous, Mongolia. Zofia Kiel,an-Jaworowska [zkielnn@twarda,pan.pl], InsĘtut Paleobiologii PAN, ul. Twarda 5 I /5 5, PL-00-8 I 8 Warszawa, Poland. DemberĘin Dash7eveg, Geological Institute, Mongolian Academy of Sciences, Ulan Bator, Mongolia. Introduction Beliajeva et al. (1974) reportedthe discovery of Early Cretaceous mammals at the Khoboor locality (referred to also sometimes as Khovboor), in the Guchin Us Soinon (County), Gobi Desert, Mongolia.
    [Show full text]