Palæos:		Unit 360:Theropoda
The Vertebrates		400: Maniraptoriformes

Theropoda: Maniraptoriformes

Ornithomimus

DINSAUROMORPHA
|--ORNITHISCHIA
`--+--SAUROPODOMORPHA
   `--Theropoda
      |--Ceratosauria
      `--Tetanurae
         |--Torvosauroidea
         `--Avetheropoda
            |--Carnosauria
            `--Coelurosauria
               |--Coelurus  
               `--Maniraptoriformes
                  |--+--Ornithomimosauria
                  |  `--Tyrannosauroidea
                  `--Maniraptora
                     |--Dromaeosauridae
                     `--AVES            

Taxa on This Page

1. Maniraptoriformes
2. Ornithomimosauria X

Descriptions

Maniraptoriformes: Scipionyx? Could be basal coelurosaur. Defined as Ornithomimus + birds. Holtz (1996a).

Range: From the Late Jurassic. 

Phylogeny: Coelurosauria::: Coelurus + *: (Ornithomimosauria + Tyrannosauroidea) +Maniraptora). 

Description: $ 3rd antorbital fenestra; brain enlarged; bony secondary palate; $ elongated ant cervical zygapophyses; $ obturator process on ischium is distal; ischium ends in point; length of forelimb 75%+ of presacral spine; ulna bowed posteriorly; $ semilunate carpal (fusion of distal carpals I&II) which permits hand to flex both laterally and dorso-ventrally (grasping and avian flight stroke); $ thin, bowed metacarpal III. 

Links: DD: Maniraptoriformes; Cladograms: The Groups of Dinosaurs; GEOL 104 Lecture 20: Theropoda II; Maniraptoriformes (German); GEOL 104 Lecture 20- Theropoda II- Tyrants, raptors, ostrich ... (Holtz lecture notes).  ATW030829 

Ornithomimosauria: Ornithomimus, Gallimimus. Used here as Ornithomimus > real birds (i.e. = Arctometatarsalia)

Range: Early to Late Cretaceous of Europe & North America.

Phylogeny: Maniraptoriformes:: Tyrannosauroidea  + *. 

Characters: Gracile, cursorial, with (moderately?) long neck and tail; $ enlarged, beak-like premaxilla; premaxilla with long posterior process separating maxilla from nasal [H+01]; long, shallow snout formed dorsally by elongated nasal; nares at tip of snout between premaxilla and nasal; elongated antorbital fossa with 2-3 fenestrae; very large orbits; bone capsule of unknown function at base of braincase; braincase and overlying frontals are strongly domed, sloping forward smoothly on the frontals and nasals and back sharply on parietals; postorbital skull short; squamosal with pneumatic recess [H00*]; lower temporal fenestra reduced; in derived species, quadrate slopes anteroventrally, lower jaw is offset anteriorly and articulates below the orbit (which might just explain the mystery capsule); $ secondary palate created by maxilla and premaxilla; toothless in almost all species; premaxillary teeth incisor-like with both carinae of each tooth being placed along the same plane perpendicular to the main axis of the skull [H00*]; teeth, where present, lack serrations [H+01]; vertebrae 10+13+5-6+<40; caudals moderately elongated, with low spines & short ribs fused to centra; dorsals with taller spines; caudals have transverse processes proximally which apparently retrovert (and articulate?) distally; large pectoral girdle with especially large coracoid bearing posteroventral process & large tubercle for biceps; clavicles unknown & girdle may be mobile; sternum in 1 species.; $ gracile, straight humerus with reduced deltopectoral crest [H+01]; ulna & radius adhere distally; carpals flat, reduced & perhaps could not flex; semilunate carpal block reduced or absent [H00*]; $ long hand; $ metacarpals equal length; $ same for digits; $ unguals straight, with weak flexor tubercles [H+01]; strongly probubic, with pubes fused; semicircular scar on posterior face of ischium {H00*]; tibia elongate [H+01]; $ metatarsus elongated to ~80% length of tibia; $ short, stout pedal digits; pes V absent [$MB89].  

Note:  [1] Ornithomimosaurs are often said to "resemble an ostrich," however the posture was quite different as currently reconstructed. [2] A recent report in Nature (Aug. 30, 2001) announces the discovery of keratinous beak fragments in Gallimimus suggesting a filter-feeding adaptation similar to a duck. [3] There is ongoing debate about whether some species were herbivores. The recent discovery of gastroliths is a strong argument in favor of this idea. [4] Characters ascribed to [H00*] are those which unite ornithomimids and tyrannosaurs.  

Links: DD: Ornithomimosauria; Harpymimus; Garudimimus; Gallimimus; (all 3 from the high-quality Nakasato Museum site); ornithomimosauria cladogram; Gallimimus (life reconstruction); Ornithomimosauria -- The Dinosauricon; Ornithomimidae; VPTHEROPOD; Ornithomimosauria ; ‹°—³ƒf[ƒ^W |ƒ^| (Japanese); Untitled Document (Hungarian). 

References: Holtz (2000) [H00], Hutt et al. (2001) [H+01], Mader & Bradley (1989) [MB89].  ATW 020128.

checked ATW050619