[D] Amtocephale gobiensis [sG] [T]
Watabe, Tsogtbaatar & Sullivan 2011
Cretaceous Late Turonian Coniacian Santonian
Ornithischia Genasauria Cerapoda Marginocephalia Pachycephalosauria Pachycephalosauridae
Baynshirenskaya Svita, [Bayn Shireh Formation - Sheeregeen Gashoon Formation - Baynshire Suite] Amtgai, southern Gobi Desert, Mongolia
A nearly complete pachycephalosaurid frontoparietal dome, from the Baynshire Formation at Amtgai, southern Gobi Desert, Mongolia, is identified as a new taxon. Amtocephale gobiensis n. gen., n. sp. differs from all other pachycephalosaurids in a combination of features that include: deep supratemporal fossae; broad (craniocaudally) prefrontal sutural surfaces with the nasal; prefrontal and anterior supraorbital sutural surfaces lying in a single plane; short parietal (parietal length to the frontoparietal length is 2.44); the medial posterior extension the parietal sharply downturned and wide relative to the maximum width of the frontoparietal; and lacking supratemporal fenestrae. Amtocephale gobiensis may be the oldest known pachycephalosaurid as it comes from rocks that are no younger than late Santonian. While it may be the oldest known pachycephalosaurid, phylogenetic analysis Amtocephale gobiensis suggests relationship to the more derived pachycephalosaurids.
The generic name is derived from the locality of Amtgai from where the specimen was collected and from the Greek “cephalo” meaning head. | The species name “gobiensis,” is in reference to the Gobi Desert, Mongolia, the general region where the specimen was found.
MPC-D 100/1203, nearly complete frontoparietal.
Amtgai, southern Gobi Desert, Mongolia. Formation/Age: Baynshire Suite (Formation)/early Late Cretaceous (Turonian-Santonian).
A small pachycephalosaurid that differs from [Prenocephale] [Prenocephale brevis?] and all other pachycephalosaurids in having the following combination of characters: deep supratemporal fossae; broad (craniocaudally) prefrontal sutural surfaces with the nasal prefrontal and anterior supraorbitals surfaces lying in a single plane; short parietal (parietal length to the frontoparietal length is 2.44); posterior medial extension of the parietal sharply downturned; posterior medial extension of the parietal wide relative to the maximum width of the frontoparietal; and supratemporal fenestrae absent.