Homalocephale

From Wikipedia, the free encyclopedia
(Redirected from Homalocephalidae)

Template:Short description Template:DMCA

Script error: No such module "Autotaxobox".
Script error: No such module "Automated taxobox".
Temporal range: Late Cretaceous, Maastrichtian
<div style="position:absolute; height:100%; left:0px; width:Expression error: Unexpected < operatorpx; padding-left:5px; text-align:left; color:inherit; background-color:rgb(254,217,106); background-image: linear-gradient(to right, rgba(255,255,255,1), rgba(254,217,106,1) 15%, rgba(254,217,106,1));">PreꞒ
<div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(127,160,86); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">
<div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(0,146,112); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">O <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(179,225,182); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">S <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(203,140,55); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">D <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(103,165,153); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">C <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(240,64,40); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">P <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(129,43,146); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">T <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(52,178,201); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">J <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(127,198,78); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">K <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(253,154,82); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">Pg <div style="position:absolute; height:100%; text-align:center; color:inherit; background-color:rgb(255,230,25); left:Expression error: Unexpected < operatorpx; width:Expression error: Unexpected < operatorpx;">N
Expression error: Unexpected < operator

Expression error: Unexpected < operator

Lua error in package.lua at line 80: module 'Module:InfoboxImage/data' not found.
Mounted holotype in the Mongolian Natural History Museum, 2002
Scientific classification Edit this classification
Script error: No such module "Taxobox ranks".: <div style="display:inline" class="script error: no such module "taxobox ranks".">Template:Taxon infoTemplate:Taxon italics
Binomial name
Template:Taxon infoTemplate:Taxon italics
Maryanska & Osmolska, 1974
Lua error in package.lua at line 80: module 'Module:InfoboxImage/data' not found.

Page Template:Taxobox/core/styles.css has no content.Template:Taxonbar/candidateTemplate:Speciesbox/parameterCheckScript error: No such module "Check for conflicting parameters".

Homalocephale (from Greek ὁμαλός, homalos, "even", and κεφαλή, kephalē, "head") is a genus of pachycephalosaurid dinosaur that lived during the Late Cretaceous period of what is now the Nemegt Formation, Mongolia. The genus was described in 1974 by Halszka Osmólska and Teresa Maryańska, and consists of a single species, H. calathocercos. Though Homalocephale has been regarded as a synonym (and juvenile form) of Prenocephale, juvenile specimens of the latter indicate that they were distinct. Homalocephale was 1.8 m (5.9 ft) long and possibly an omnivore.

Discovery

File:Homalocephale calathoceros.jpg
Skeletal diagram of the holotype

The type species, H. calathocercos, was described from an incomplete skull and postcranial material (holotype MPC-D 100/1201) from the Nemegt locality of the Nemegt Formation. The specimen has large openings on the top of the skull, a distinct frontoparietal suture, low and long infratemporal fenestrae, and a large, round eye socket. The forehead is notably rough, with multiple nodules on the lateral and posterior sides of the squamosal bone. Paleontologists concluded that the specimen was an adult, despite the fact that the sutures are discernible and that it had a flat skull (a juvenile trait in many pachycephalosaurid species).[1]

In 2010, a study by Nick Longrich and colleagues suggested that flat-headed pachycephalosaurs were just juvenile forms of dome-headed adults, a view also supported by the earlier analysis of Horner and Goodwin in 2009. Longrich and colleagues suggested that Homalocephale is actually the juvenile or sub-adult stage of Prenocephale mainly based on the lack of a dome and being discovered in the same locality (Nemegt) as the latter.[2]

David C. Evans and team in 2018 reported juvenile specimens of Prenocephale from the Nemegt Formation, noting a relatively linear growth in this pachycephalosaur characterized by a rounded dome. This differs from the flat skull of Homalocephale and given that even juvenile Prenocephale possessed a rather rounded dome, both taxa should be regarded as separate.[3]

Description

File:Homalocephale body.jpg
Life restoration

Homalocephale was about 1.8 m (5.9 ft) long.[4] Unlike other definitely adult pachycephalosaurs (though similar to probable juvenile specimens referred to Dracorex and Goyocephale), Homalocephale sported a flat, wedge-shaped skull roof. Nonetheless, the surface of the skull was fairly thickened.[1]

Classification

File:Homalocephale skull.jpg
Cast of the holotype skull

Below is a cladogram from Template:Harvp.[5]

Script error: No such module "Clade".

Paleobiology

File:Homalocephale and Saurolophus herd.jpg
Two Homalocephale with Saurolophus herd behind

Homalocephale is also noted for having an unusually broad pelvis and some have suggested that the width served to protect vital organs from harm during flank-butting. Others think that they were for giving birth to live young, instead of laying eggs.[6] Homalocephale also had rather long legs, indicating a fast-moving gait.[7]

See also

References

Page Template:Reflist/styles.css has no content.

  1. ^ a b Page Module:Citation/CS1/styles.css has no content.Maryańska, T.; Osmólska, H. (1974). "Pachycephalosauria, a new suborder of ornithischian dinosaurs" (PDF). Palaeontologica Polonica (30): 45−102.
  2. ^ Longrich, N.R., Sankey, J. and Tanke, D. (2010). "Texacephale langstoni, a new genus of pachycephalosaurid (Dinosauria: Ornithischia) from the upper Campanian Aguja Formation, southern Texas, USA." Cretaceous Research, . Script error: No such module "CS1 identifiers".
  3. ^ Page Module:Citation/CS1/styles.css has no content.Evans, D. C.; Hayashi, S.; Chiba, K.; Watabe, M.; Ryan, M. J.; Lee, Y.-N.; Currie, P. J.; Tsogtbaatar, K.; Barsbold, R. (2018). "Morphology and histology of new cranial specimens of Pachycephalosauridae (Dinosauria: Ornithischia) from the Nemegt Formation, Mongolia". Palaeogeography, Palaeoclimatology, Palaeoecology. 494: 121−134. Bibcode:2018PPP...494..121E. doi:10.1016/j.palaeo.2017.11.029.
  4. ^ Holtz, Thomas R. Jr. (2008) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages Supplementary Information
  5. ^ Page Module:Citation/CS1/styles.css has no content.Evans DC, Schott RK, Larson DW, Brown CM, Ryan MJ (2013). "The oldest North American pachycephalosaurid and the hidden diversity of small-bodied ornithischian dinosaurs". Nature Communications. 4 1828. Bibcode:2013NatCo...4.1828E. doi:10.1038/ncomms2749. PMID 23652016.
  6. ^ Page Module:Citation/CS1/styles.css has no content.Carpenter, Kenneth (1997). "Agonistic behavior in pachycephalosaurs (Ornithischia:Dinosauria): a new look at head-butting behavior". Contributions to Geology. 32 (1): 19–25.
  7. ^ Page Module:Citation/CS1/styles.css has no content.Maryańska, Teresa; Chapman, Ralph E.; Weishampel, David B. (2004). "Pachycephalosauria". In Weishampel, David B.; Dodson, Peter; Osmólska Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 464–477. ISBN 0-520-24209-2.

Sources

Lua error in mw.title.lua at line 404: bad argument #2 to 'title.new' (unrecognized namespace name 'Portal').

Template:Pachycephalosauria Script error: No such module "Taxonbar".