Stenopelix Pelvis
   HOME

TheInfoList



OR:

''Stenopelix'' (meaning "narrow
pelvis The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...
") is a
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 ...
of probable basal
ceratopsia Ceratopsia or Ceratopia ( or ; Ancient Greek, Greek: "horned faces") is a group of herbivore, herbivorous, beaked dinosaurs that thrived in what are now North America, Asia and Europe, during the Cretaceous Period (geology), Period, although ance ...
n from the
Early Cretaceous The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
of
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
. It lived in the late
Berriasian In the geological timescale, the Berriasian is an age/ stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 143.1 ±0.6 Ma and 137.05 ± 0.2 (million years ago) ...
Stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...
of the Cretaceous period, approximately 140 myr ago.Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'
Winter 2010 Appendix.
/ref> The genus is based on a partial skeleton lacking the skull, and its classification is based on characteristics of the hips.


Discovery and species

In 1855, in a
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
quarry near Bückeburg on the Harrl, a fossil was found of a small dinosaur. Most of its bones were in a poor condition and removed on preparation, leaving two sets of hollow impressions on the plate and counterplate. The two plates do not overlap completely. The hollows, serving as a natural mold, have since been used to produce several casts in
gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate Hydrate, dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk ...
and
latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature, but synthetic latices are common as well. In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all floweri ...
to facilitate the study of the specimen. It was originally part of the collection of Max Ballerstedt preserved in the Bückeburg Gymnasium Adolfinum*Hermann Schmidt, 1969, "''Stenopelix valdensis'' H. v. Meyer, der kleine Dinosaurier des norddeutschen Wealden", ''Paläontologische Zeitschrift'' 43(3/4): 194-198 but was in 1976 moved to the Georg-August-Universität Göttingen where it now resides in the collection of the Geowissenschaftliches Zentrum der Universität Göttingen. In 1857, based on this fossil,
Christian Erich Hermann von Meyer Christian Erich Hermann von Meyer (3 September 1801 – 2 April 1869), known as Hermann von Meyer, was a German palaeontologist. He was awarded the 1858 Wollaston medal by the Geological Society of London. Life He was born in Frankfurt am ...
named 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 ...
''Stenopelix valdensis''. The generic name is derived from Greek ''stenos'', "narrow", and ''pelyx'', "pelvis". The
specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...
refers to the Wealden Formation. 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 ...
, GZG 741/2 (earlier GPI 741–1, 2), found in the Obernkirchen Sandstein Formation, consists of the impressions of an almost complete skeleton, lacking the skull and the neck.


Description

''Stenopelix'' was a small herbivorous animal, reaching in length and in body mass. The preserved rump and tail have a combined length of just 97 centimetres; the femur is fourteen centimetres long. The species can be distinguished by several details of the pelvis. The shaft part of the ilium uniformly tapers ending in a rounded point. The shaft of the
ischium The ischium (; : is ...
is thickest in the middle and there shows a distinctive kink.


Classification

The classification of ''Stenopelix'' is controversial and has ever been problematic because of the lacking skull. Prior to the 1960s, it was often assigned to some
ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (). They represent one of the most successful groups of herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and relatively sm ...
group. In 1974
Teresa Maryańska Teresa Maryańska (1937 – 3 October 2019) was a Polish paleontologist who specialized in Mongolian dinosaurs, particularly pachycephalosaurians and ankylosaurians. She is considered not only as one of Poland's but also one of the world's leadin ...
suggested it to be a pachycephalosaur, one of the oldest known, due to the apparent exclusion of the pubis from the
acetabulum The acetabulum (; : acetabula), also called the cotyloid cavity, is a wikt:concave, concave surface of the pelvis. The femur head, head of the femur meets with the pelvis at the acetabulum, forming the Hip#Articulation, hip joint. Structure The ...
, and the presence of strong caudal ribs. Peter Galton in 1982 showed that the "pubis" was actually part of the acetabulum, and the so-called "caudal ribs" were sacral ribs. The curvature of the
ischium The ischium (; : is ...
and absence of an
obturator foramen The obturator foramen is the large, Bilateral symmetry, bilaterally paired opening of the bony pelvis. It is formed by the pubis and ischium. It is mostly closed by the obturator membrane except for a small opening, the obturator canal, through wh ...
were not characteristics seen in other pachycephalosaurs. Galton concluded ''Stenopelix'' to be ceratopian. However, exact
cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...
analyses by
Paul Sereno Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago who has discovered several new dinosaur species on several continents, including at sites in Inner Mongolia, Argentina, Morocco and Niger. ...
have resulted in a position in the
Pachycephalosauria Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, most pachyceph ...
. But
paleontologists Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...
Richard J. Butler and Robert M. Sullivan nonetheless view the species as being Marginocephalia ''
incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
'', rejecting the presumed
synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to ...
with the Pachycephalosauria as incorrect identifications or lacking cogency because of a possible presence in ceratopsian groups. A
cladistic analysis Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...
performed by Butler et al. (2011) showed that ''Stenopelix'' is a basal member of the
Ceratopsia Ceratopsia or Ceratopia ( or ; Ancient Greek, Greek: "horned faces") is a group of herbivore, herbivorous, beaked dinosaurs that thrived in what are now North America, Asia and Europe, during the Cretaceous Period (geology), Period, although ance ...
, and its sister taxon is ''
Yinlong ''Yinlong'' (, meaning "hidden dragon") is a genus of basal ceratopsian dinosaur from the Late Jurassic Period of China. By far the earliest known ceratopsian, it was a small, primarily bipedal herbivore. Discovery and species A coalition of ...
''. Morschhauser et al. (2019) recovered ''Stenopelix'' within Neoceratopsia. Yu et al. (2020) classified ''Stenopelix'' as a chaoyangsaurid with ''Yinlong'', '' Chaoyangsaurus, Xuanhuaceratops, Hualianceratops.'' Fonseca et al. (2024) also recovered this genus as a chaoyangsaurid close to ''Yinlong''.


See also

* Timeline of ceratopsian research


References


External links

* {{Taxonbar, from=Q134600 Ceratopsia Dinosaur genera Berriasian dinosaurs Taxa named by Christian Erich Hermann von Meyer Fossil taxa described in 1857 Dinosaurs of Germany