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Euoplocephalus



     I finally got the stupid thing done.  Again, criticize or make 
suggestions on ANYTHING that you don't like.  If you only have a little 
bit to say, you might want to send it just to me.       
     The part where I talk about contemporaneous  dinosaur genera and species 
is probably a bit outdated, since 1) my primary source was DINOSAURIA, 
and 2) I only asked previously for clarification on tyrannosaurs and 
ceratop(s)ians.  If you are willing to wade through it all, 
its much appreciated (The Judith River is a fantastically rich dinosaur 
locality, so most "paleoecology" sections wont be this long).  I am 
unaware of any post-1990 Two-Medicine/Judith River/Horsesheoe Canyon 
genera except Achelosaurus and Einisaurus, so please fill me in if you 
know any more.
     I repetitively  alternate between "included" (which sounds like I'm 
not listing them all) and
"consisted of" (which implies there weren't any others) when talking 
about dinosaur groups.  Any suggestions on how to phrase these better would be
 appreciated. 
    Especially uncertain points are marked with an asterisk and a number.  The
specific queries are grouped together before the bibliography.  Thanks in 
advance for any comments, and thanks again to all who answered my original 
questions.  
 
LN Jeff
------------------------------------------------------------------------------

GENUS _Euoplocephalus_ (Lambe, 1910)
Synonyms: _Stereocephalus_ (Lambe, 1902)
          _Palaeoscincus_ (Lambe, 1902)
          _Anodontosaurus_ (Sternberg, 1929)
          _Dyoplosaurus_ (Parks, 1924)
          _Scolosaurus_ (Nopsca, 1928b)

_Euoplocephalus_ _tutus_ (Lambe, 1910)
Etymology:(Greek) Eu ("well", "good") + oplos ("armoured") + kephale ("head")
        (*1) tutus ("safe, secure)  
Synonyms: _Stereocephalus_ _tutus_ (Lambe, 1902)
          _Palaeoscincus_ _asper_ (Lambe, 1902)
          _Dyoplosaurus_ _acutosquamaeus_ (Parks, 1924)
          _Scolosaurus_ _cutleri_ (Nopsca, 1928a)
          _Anodontosaurus_ _lambei_ (Sternberg, 1929)    
Holotype: NMC 210
Referred specimens: AMNH 5211, AMNH 5216, AMNH 5223, AMNH 5245, AMNH 
5266, AMNH 5337, AMNH 5403, AMNH 5404, AMNH 5405, AMNH 5406, AMNH 5409, 
AMNH 5440, AMNH 5470, BMNH R4947, BMNH R5161 (holotype: _S_._cutleri_), 
NMC 349, NMC 1349 (holotype, _P_._asper_), NMC 2252, NMC 2253, NMC 
8530 (holotype, _A_._lambei_), NMC 8876, ROM 784 (holotype: 
_D_._acutosquamaeus_), ROM 788, ROM 813, ROM 832, ROM 833, ROM 1930, ROM 
7761, ROM 7763, ROM 7764, ROM 7765, ROM 7766, ROM 7767, ROM 7770, UA 31, 
USNM 7943, USNM 8360, USNM 11892, USNM 16747  
Formation & lovation: Judith River Group
                      Montana, United States
                      Alberta, Canada  
                      Two Medicine Formation
                      Montana, United States
                      Horseshoe Canyon Formation
                      Alberta, Canada 
Age: late Campanian-early Maastrichtian

Taxonomy:
THYREOPHORA (Nopsca, 1915)
EURYPODA (Sereno, 1986)
ANKYLOSAURIA (Osborn, 1923)
ANKYLOSAURIDAE (Brown, 1908)           

Estimated (adult) length: 6-7 meters
Estimated (adult) body weight: ~2 tonnes

Paleoecology:
     _Euoplocephalus_ _tutus_ was the most common ankylosaur in western 
North America during its time.  Its armour consisted of plates, scutes, 
ossicles and keels arranged in transverse bands across the body.  The 
scutes were heavily vascularized, and may have served a thermoregulatory 
function.  The head was very well armoured, even down to having armour plates 
on the eyelids.  The fair degree of lateral flexibility in the anterior 
caudals, combined with the fused caudals and ossified tendons of the distal 
part of the tail, made the club a formidible weapon.  The nasal 
passages were fairly complex, and may have given _E_._tutus_ a good sense of 
smell.  However, it has also been suggested that they served to warm 
and moisten inhaled air as in modern endotherms.    

     The late Campanian Two Medicine Formation was formed on the upper 
part of a coastal plain, near the young Rocky Mountains.  The climate 
here was semi-arid, with small streams and seasonal lakes (*2).  Vegetation 
consisted of berry bushes, dogwoods (*3), evergreens, and cycads.  
     Ornithopods from this area consisted of the hypsilophodont 
_Orodromeus_ _makelai_ and lambeosaurine and hadrosaurine 
hadrosaurs, including _Maiasaura_ _peeblesorum_.  
     Ceratopsians included _Achelousaurus_ _horneri_, _Brachyceratops_ 
_montanenesis_, _Chasmosaurus_, _Einiosaurus_ _procurvicornis_, 
_Styracosaurus_ _ovatus_, and possibly _Centrosaurus_ and _Leptoceratops_ 
(*5).  
     The nodosaurid  _Edmontonia_ _rugosidens_ is known from this 
formation, in addition to the ankylosaurid _Euoplocephalus_ _tutus_. 
     The small theropods _Troodon_ _formosus_, _Dromaeosaurus_, and 
_Saurornitholestes_ (*6) were present, as were the larger forms 
_Albertosaurus_ and _Aublysodon_ _mirandus_.

     The Judith River Group was formed on the lower part of the same 
coastal plain as the Two Medicine Formation, lying adjacent to the 
Western Interior Seaway.  The climate was wetter, with swamps, 
freshwater ponds, and meandering rivers flowing into the sea.  The vegetation 
here was more abundant and included ferns, palms, and cycads growing in the 
shadows of cypress, pine, sequoia, magnolia, dogwood, and poplar trees.  
     Dinosaurs were more common and diverse here (*7).  Ornithopods 
included of the the hypsilophodont _Thescelosaurus_ _negelctus_, the 
hadrosaurines  _Brachylophosaurus_ _canadensis_, _B_._goodwini_, 
_Prosaurolophus_ _maximus_, _Gryposaurus_ _notabilis_, "Kritosaurus" 
incurvimanus, and possibly _Maiasaura (*9).  Lambeosaurines included 
_Corythosaurus_ _casuarius_, _Lambeosaurus_ _lambei_, _L_. _magnicristatus_, 
and _Parasaurolophus_ _walkeri_.  (Indeterminate hadrosaur remains include 
_Cionodon_ _stenopsis_, _Dysganus_ _encaustus_, _Diclonius_ _pentagonus_, 
_D_. _calamarius_, _Hadrosaurus_ _breviceps_, _H_. _paucidens_, _Pteropelyx_ 
_grallipes_, _Trachodon_ _altidens_, _T_. _marginatus_, _T_._mirabilis_, 
and _T_. _selwyni_).  
     Pachycephalosaur remains  include _Stegoceras_ _validum_, 
_Gravitholus_ _albertae_, _Ornatotholus_ _browni_, and 
_Pachycephalosaurus_.  
     Ceratopsians included _Avaceratops_ _lammersi_, _Anchiceratops_ 
_ornatus_, _Chasmosaurus_ _belli_, _C_. _russelli_, _Monoclonius_ _crassus_, 
_Centrosaurus_ _apertus_,  and _Styracosaurus_ _albertensis_.  
(Indeterminate ceratopsian remains include _Ceratops_ _montanus_, 
_Monoclonius_ _recurvicornis_,  _M_. _sphenocerus_, _M_. _fissus_, 
_Dysganus_ _peiganus_, _D_._bicarinatus_, _D_. _encaustus_, and _D_. 
_haydenianus_).  
     Ankylosaurs consisted of the nodosaurids _Edmontonia_ _rugosidens_, 
_E_._longiceps_, and _Panoplosaurus_, as well as the 
ankylosaurid _Euoplocephalus_ _tutus_ (Indeteriminate ankylosaur remains 
include _Palaeoscincus_ _costatus_).  
     Theropod included the poorly known _Richardoestesi_ 
_gilmorei_ and the troodont _Troodon_ _formosus_ (Indeterminate  
troodont remains include _Paronychodon_ _lacustris_ and _Zapsalis_ 
_abradens_)  The dromaeosaurs _Dromaeosaurus_ _albertensis_ and 
_Saurornitholestes_ _langstoni_, the elmisaurids _Chrirostenotes_ and 
_Elmisaurus_ _elegans_, the caenagnathids _Caenagnathus_ _collinsi and 
_C_._sternbergi_, and the ornithomimids _Struthiomimus_ _altus_, 
_Dromicieomimus_ _samueli_, and _Ornithomimus_ were also present 
(Indeterminate ornithomimid remains include _Ornithomimus_ _tenuis_).  
Large theropods consisted of _Albertosaurus sarcophagus_, 
_Gorgosaurus_ _libratus_, _Daspleteosaurus_ _torosus_, and _Aublysodon_ 
_mirandis_ (Indeterminate theropods include _Laelaps_ _explanatus_, 
_L_. _laevifrons_, and _Aublysodon_ _lateralis_).  
     Also known from the Judith River Formation is a segnosaur possibly 
referrable to _Erlikosaurus_ (*10).

     The early Maastrichtian Horseshoe Canyon Formation was 
laid down on the same lower coastal plain of the Judith 
River Formation (*11).
      Ornithopods included the hypsilophodont _Parksosaurus_ _warreni_ and 
the hadrosaurines _Edmontosaurus_ _regalis_, _Saurolophus_ _osborni_, 
and _Hypacrosaurus_ _altispinus.  
      Pachycephalosaurs included _Stegoceras_ _edmontonense_.
      Ceratopsian included  _Anchiceratops_ _ornatus_, _Arrhinoceratops_ 
_brachyops_, and _Pachyrhinosaurus_ _canadensis_.
      Ankylosaurs consisted of the nodosaurid _Edmontonia_ _longiceps_, as 
well as the ankylosaurid _Euoplocephalus_ _tutus_.
     The ornithomimids _Ornithomimus_ _edmontonensis_, _Struthiomimus_ 
_altus_, _Dromicieomimus_ _brevitertius_, the elmisaurid _Chirostenotes 
pergracilis_, the troodont _Troodon_ _formosus_, and the dromaeosaurs 
_Dromaeosaurus_ and _Saurornitholestes_ (*13) were also present.  Large 
theropods inlcuded _Albertosaurus_ _sarcophagus_ and _Daspletosaurus_(*14).     
             

*1: Is this greek as well?     
*2: Is "seasonal" the right word here?  Meaning they dry up each year.
*3: Are both of these angiosperms?
*5: Anyone know anything about these presence of these two?
*6: Does this belong under Troodon?
*7: For real or a bias of the fossil record?
*9 Anyone know anything about this?
*10: How about this?  Any other segnosaur remains?
*11: A little more info on the environment here would be nice.  I assume 
the coastal plain was now larger because the sea was shrinking?
*13: Dinosauria lists "cf. Dromaeosaurus sp.", so how concrete are the 
remains?  Again, is Saurornitholestes valid?
*14: Anyone know anything about Horseshoe Canyon Daspletesaus remains?
    Finally: which ceratopsians are thought to represent ontogenetic 
growth stages of a single genus?  What other sorts of critters besides 
dinosaurs were important in the Two Medicine, Judith River, and Horseshoe 
Canyon Formations?

PUBLICATIONS

Brown, B. 1908. The Ankylosauridae, a new family of armored dinosaurs 
   from the Upper Cretaceous. Bull. Am. Mus. Nat. Hist. 24: 187-201
Carpenter, K. 1982. Skeletal and dermal armor reconstruction of 
   _Euoplocephalus_ _tutus_ (Ornithischia: Ankylosauridae) from the Late 
   Cretaceous Oldman Formation of Alberta. Can. J. Earth Sci. 19: 689-697
Coombs, W.P., Jr. 1971. The Ankylosauria. Ph.D. dissertation, Columbia 
   Univ., New York.
---- 1972. The bony eyelid of _Euoplocephalus_ (Reptilia, Ornithischia). 
   J. Paleontol. 46: 637-650
---- 1978a. The families of the ornithischian dinosaur order Ankylosauria. 
   Palaeontology. 21: 143-170
---- 1978b. Forelmb muscles of the Ankylosauria (Reptilia, Ornithischia). 
   J. Paleontol. 52: pp. 642-658
---- 1978c. Theoretical aspects of the cursorial adaptations in 
   dinosaurs. Q. Rev. Biol. 53: 393-418  
---- 1978d. An endocranial cast of _Euoplocephalus_ (Reptilia, 
   Ornithischia). Palaeontographica A 161: 176-182. 
---- 1979. Osteology and myology of the hindlimb in the Ankylosauria 
   (Reptilia, Ornithischia). J. Paleontol. 53: 666-684
---- 1986. A juvenile ankylosaur referrable to the genus _Euoplocephalus_ 
   (Reptilia, Ornithischia). J. Vert. Palaeontol. 6: 162-173 
Lambe, L.M. 1902. New genera and species from the Belly River Series 
   (mid-Cretaceous). Contrib. Canadian Palaeontol. Geol. Surv. Can. 3: 25-81
---- 1910. Note on the parietal crest _Centrosaurus_ _apertus_, and a 
   proposed new generic name for _Stereocephalus_ _tutus_. Ottawa Nat. 14: 
   149-151
Nopsca, F. 1928a. Paleontological notes on reptiles. Geol. Hungarica, 
   Ser. Paleontol. 1: 1-84
---- 1928b. The genera of reptiles. Paleobiologica, 1: 163-188 
Olshevsky, G. 1979. The ankylosaur family tree. George Olshevsky, San 
   Diego, CA. (Private printing)
Parks, W.A. 1924. _Dyoplosaurus_ _acutosquameus_, a new genus and species 
   of armoured dinosaur; with notes on a skeleton of _Prosaurolophus_ 
   _maximus_. Univ. Toronto Stud. (Geol. Ser.) 18: 1-35
Sereno, P.C. 1986. Phylogeny of the bird-hipped dinosaurs (Order 
Ornithischia). Natl. Geogr. Soc. Res 2: 234-256 
Sternberg, C.M. 1929. A toothless armoured dinosaur from the Upper 
   Cretaceous of Alberta. Bull. Natl. Mus. Can. 54: 28-33