''Gargoyleosaurus'' (meaning "

gargoyle In architecture, and specifically Gothic architecture, a gargoyle () is a carved or formed Grotesque (architecture), grotesque with a spout designed to convey water from a roof and away from the side of a building, thereby preventing it from ...

lizard") is one of the earliest

ankylosaurs Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with Armour (zoology), armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short ...

known from reasonably complete fossil remains. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

was discovered in 1995 at the Bone Cabin Quarry West locality, in Albany County,

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

in exposures of the Upper

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

(

Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 154.8 ±0.8 Ma and 149.2 ±0.7 Ma (million years ago). The Kimmeridgian follows the Oxfordian ...

Tithonian In the geological timescale, the Tithonian is the latest age (geology), age of the Late Jurassic Epoch and the uppermost stage (stratigraphy), stage of the Upper Jurassic Series. It spans the time between 149.2 ±0.7 annum, Ma and 143.1 ±0.6 (mi ...

stages)

Morrison Formation The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltston ...

. The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

, ''G. parkpinorum'' (originally ''G. parkpini'') was described by Ken Carpenter ''et al.'' in 1998. A mounted skeletal reconstruction of ''Gargoyleosaurus parkpinorum'' can be seen at the Denver Museum of Nature and Science and, alongside a couple skeletons of baby ''

Stegosaurus ''Stegosaurus'' (; ) is a genus of herbivorous, four-legged, armored dinosaur from the Late Jurassic, characterized by the distinctive kite-shaped upright plates along their backs and spikes on their tails. Fossils of the genus have been fo ...

'', has been on display there since around 2002. ''Gargoyleosaurus'' was present in stratigraphic zone 2 of the Morrison Formation.Foster, J. (2007). "Appendix." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their World''. Indiana University Press. pp. 327–329.

Discovery

The holotype specimen of ''Gargoyleosaurus parkpinorum'' was collected by Western Paleontology Labs in 1995 and is currently held in the collections of the Denver Museum of Nature and Science,

Denver Denver ( ) is a List of municipalities in Colorado#Consolidated city and county, consolidated city and county, the List of capitals in the United States, capital and List of municipalities in Colorado, most populous city of the U.S. state of ...

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

. Besides the holotype, two other partial skeletons are known (although not yet described). The holotype consists of most of the skull and a partial postcranial skeleton. The specimen was originally described as ''Gargoyleosaurus parkpini'' by Carpenter, Miles and Cloward in 1998, then renamed ''G. parkpinorum'' by Carpenter ''et al.'' in 2001, in accordance with

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its formal author, t ...

art. 31.1.2A.

Description

''Gargoyleosaurus'' was a relatively small ankylosaur, reaching in length and in body mass. Much of the

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

and

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

has been recovered, and the

taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

displays cranial sculpturing, including pronounced

deltoid Deltoid (delta-shaped) can refer to: * The deltoid muscle, a muscle in the shoulder * Kite (geometry), also known as a deltoid, a type of quadrilateral * A deltoid curve, a three-cusped hypocycloid * A leaf shape * The deltoid tuberosity, a part o ...

quadratojugal The quadratojugal is a skull bone present in many vertebrates, including some living reptiles and amphibians. Anatomy and function In animals with a quadratojugal bone, it is typically found connected to the jugal (cheek) bone from the front and ...

and

squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestra ...

bosses. The taxon is further characterized by a narrow rostrum (in dorsal view), the presence of seven conical teeth in each

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

, an incomplete osseous nasal septum, a linearly arranged nasal cavity, the absence of an osseus

secondary palate The secondary palate is an anatomical structure that divides the nasal cavity from the oral cavity in many vertebrates. In human embryology, it refers to that portion of the hard palate that is formed by the growth of the two palatine shelves med ...

, and, as regards osteoderms, two sets of co-ossified cervical plates and a number of elongate conical spines. A very unusual feature is the sagittal (midline) osteoderm on the first set of cervical plates; in most other ankylosaurs, these osteoderms are bilateral, i.e. paired with one on each side of the midline. Kilbourne, B. and Carpenter, K. 2005. "Redescription of Gargoyleosaurus parkpinorum, a polacanthid ankylosaur from the Upper Jurassic of Albany County, Wyoming". ''N. Jb. Geol. Palaont. Abh.'' 237: 111–160

Classification

Vickaryous ''et al.'' (2004) place ''Gargoyleosaurus parkpinorum'' within the family

Ankylosauridae Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pal ...

of the

Ankylosauria Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs ...

and are in agreement with most previous

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

hypotheses, which place the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

as the

sister group In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to all other ankylosaurids (i.e., members of the Ankylosauridae). These studies however, only utilized the skull, whereas many of the distinctive features of the family Polacanthidae are in the postcranial skeleton. In contrast, a phylogenetic analysis by Soto-Acuña and colleagues in 2021 recovered ''Gargoyleosaurus'' as a nodosaurid. Below is a reproduced phylogenetic analysis from Soto-Acuña ''et al.'' (2021):

References

* Carpenter, K., Miles, C. and Cloward, K. (1998). "Skull of a Jurassic ankylosaur (Dinosauria)." ''Nature'' 393: 782–783. * Carpenter, K. (ed.) ''The Armored Dinosaurs''. pp. 454–483. Indiana University Press, Bloomington. * Vickaryous, Maryanska, and Weishampel (2004). "Ankylosauria". in ''The Dinosauria'' (2nd edition), Weishampel, D. B., Dodson, P., and Osmólska, H., editors. University of California Press. * Killbourne, B. and Carpenter, K. (2005). "Redescription of ''Gargoyleosaurus parkpinorum'', a polacanthid ankylosaur from the Upper Jurassic of Albany County, Wyoming". ''Neues Jahrbuch für Geologie und Paläontologie'', 237, 111–160.

External links

''Gargoyleosaurus''
from the Natural History Museum {{Taxonbar, from=Q134736 Nodosauridae Dinosaur genera Kimmeridgian dinosaurs Morrison Formation Fossil taxa described in 1998 Taxa named by Kenneth Carpenter Dinosaurs of the United States

Discovery

Description

Classification

See also

References

External links