[D] Huanghetitan liujiaxiaensis [sG] [T]
Describer
You, Li, Zhou and Ji Q. 2006
Time
Cretaceous Early Cretaceous Late
Classification
Saurischia Sauropodomorpha Sauropoda Titanosauria Huanghetitanidae
Diet
Herbivore
Fossilsite
Hekou Group of Lanzhou Basin, Gansu Province, China
Info
Huanghetitan liujiaxiaensis (You, Li, Zhou and Ji Q. 2006) > Huanghetitan ruyangensis (Lü, Xu, Zhang, Hu, Wu, Jia and Ji Q. 2007)
Genus - Typespecies
Etymology
\\\"Huanghe\\\" (Chinese): Yellow River, which flows along the Lanzhou Basin where the fossils were diccovered. \\\"Titan\\\" (Greek) refers to Greek mythological giants, symbolic of great size. \\\"Liujiaxia\\\" (Chinese): Liujia Gorge, which is part of the Yellow River in Lanzhou Basin, where the Liujiaxia National Dinosaur Geopark is located nearby.
Holotype
GSLTZP02-001 (Quarry 2): Nearly complete sacrum, one proximal caudal vertebra, one middle caudal vertebra, fragmentary cervical ribs, one chevron missing its distal and, left scapula, and left coracoid. Reposited in the Fossil Research and Development Center of the Third Geology and Mineral Resourches Exploration Academy of Gansu Province in Lanzhou,
Type locality and horizon
Eastern part of the Lanzhou Basin, Gansu Province, P.R. China: Hekou Group, Lower Cretaceous (Edittorial Committee of Chinese Stratigraphic Standard, 2000)
Description
The allmost complete sacrum is composed of five coosified vertebrae, as in basal macronarians, but one fewer than in Euhelopus (Wiman, 1929) and more derived lithostrotians (Upchurch et al, 2004). The cylindrical sacral centra are fused; the first sacral has a flat canial articular surface and the last a concave caudal articular surface. The cranial surface of the first centrum is much wider than tall. No pleurocoels are developed on the lateral surfaces. The articular surfaces of the prezygapophyses of the first sacral face dorsally. The neaural arches of all five sacrals are, like their centra, fused, though the neural spines of only the first four sacrals are fused.
Automorphic to these fout fused neural spines (totalling 60 cm long) are their extremely short heights and markedly transversely expanded distal ends. The height of each neural spine is about 8 cm, but the widths of the expanded dorsal surfaces (along their caudal margins) begin at 20 cm on the first sacral and decrease caudally to 8 cm in the fourth sacral.
The sacral plate is composed of the transverse processes dorsally and the sacral ribs ventrally; these are fused to each other. In dorsal view, the transverse processes project laterally, but also slightly cranially in the first two sacrals and slightly caudally in the last three.
The dorsal surface of the proximal end of each transverse process is craniocaudally expanded and braced against the neural spine by the spinoprezygapophysal, spinodiapophysal and spinopostzygapophysal laminae. However the robustness of htese laminae varies in each individual sacral.
In ventral view, the sacral ribs expand at both the proximal end distal ends. The proximal ends of the first four ribs attach to the cranial portions of their respective centra via the parapophyses, while that of the fifth rib attaches to the midpoint of the centrum. Exept for the first, the distal ends of all the sacral ribs connect to each other, forming a sacrocostal yoke.
Two isolated caudals are preserved. One which has its neural arch occupying most of the length of the centrum, is much taller than the other. It is designated as a proximal caudal. In the other, the neural arch only occupies the proximal half of the length of the centrum, which is typical of the middle caudals of titanosauriforms.
The centrum of the proximal caudal is amphiplatyan, and has subcircular articular surfaces. The length of the centrum is shorter than the width of the articualr surface. The ventral side of the centrum bears a wide but shallow longitudinal fossa that is more prominent at its distal end due to the enlargement of the chevron articualr facets. The neural arch encompasses a relatively large neural canal that is about half as tall as the centrum. The medially facing prezygapophyses are transversely compressed, directed proximodorsally, and project slightly beyond the proximal end of the centrum. The postzygapophyses are mere facets, rather than processes. The neuraql spine is retangular in lateral view, projecting more dorsally than distally. No clear laminae develop arround the neural spine, as would be expected in a verry proximal caudal vertebrae, implying a relatively distal position for this element. The transverse processes are situated at the neuralcentral suture, and seem to trend caudolaterally.
The centrum of the middle caudal is also amphiplatyan. Its articular surfaces have subcircular outlines, although diagenetic deformation may obscure its actual configuration. The width of each articular surface is about the same as the length of the centrum, which is slightly longer than that of the proximal centrum. Differing from the proximal caudal, its prezygapophyses and neural spine project more horizontally than dorsally. Transverse processes still exists, indicating a relatively proximal position for the middle caudal.
Several fragmentary cervical ribs are preserved. One cervical rib is relatively complete, and measures 1.1 m long. Its proximal end is tetraradiate, with a short cranial process. The angle between the capitulum and the tuberculum is well bellow 90o, indicating a ventral placement of the rib relativelyto the ventral edge of its centrum.
A single chevron is represented by its proximal and and part of its distal portion. Based on its large size, this chevron is probably articulated with proximal caudals. The proximal end has two rami that are not bridged. The hemal canal enclosed by the two rami is deep.
The lateral side of the left scapula is prepared. This scapula is unique among all sauropods in having an extremely dorsoventrally expanded, plate-like acromion (83 cm tall), longer than the blade itself (70 cm). The plate is eliptical in outline, with its dorsal portion far larger than the ventral one. A low deltoid ridge runs along the caudodorsal edge of the acromion, and defines the caudal margin of a shallow fossa that occupies the bulk of the dorsal portion of the plate. The acromion and scapular body become thicker ventrally, expecially at the cranioventral edge of hte glenoid. As in Euhelopus and titanosaurians, the scapular portion of the glenoid faces not only cranioventrally, but also medially. The short blade of the scapula expands caudally, with a pronounched hook at its caudaldorsal corner. The lateral side of the blade is slightly convex, giving it a D-shaped cross-sectional morphology.
The left coracoid is a relatively flat plate, with round dorsal and cranial margins and sinouus caudal and ventral margins. The caudal margin is convex, with its apex at the midpoint, fittng a corresponding concavity on the cranial margin of the scapula. The coracoidal portion of the glenoid is transversely rugose and thick and bears a pronounched lip. Cranial to this, a notch embays the ventral margin of the element. A corcoid foramen is situated at mid-height, just cranial to the coracoid-scapula contact.
You, Li, Zhou and Ji Q. 2006
Time
Cretaceous Early Cretaceous Late
Classification
Saurischia Sauropodomorpha Sauropoda Titanosauria Huanghetitanidae
Diet
Herbivore
Fossilsite
Hekou Group of Lanzhou Basin, Gansu Province, China
Info
Huanghetitan liujiaxiaensis (You, Li, Zhou and Ji Q. 2006) > Huanghetitan ruyangensis (Lü, Xu, Zhang, Hu, Wu, Jia and Ji Q. 2007)
Genus - Typespecies
Etymology
\\\"Huanghe\\\" (Chinese): Yellow River, which flows along the Lanzhou Basin where the fossils were diccovered. \\\"Titan\\\" (Greek) refers to Greek mythological giants, symbolic of great size. \\\"Liujiaxia\\\" (Chinese): Liujia Gorge, which is part of the Yellow River in Lanzhou Basin, where the Liujiaxia National Dinosaur Geopark is located nearby.
Holotype
GSLTZP02-001 (Quarry 2): Nearly complete sacrum, one proximal caudal vertebra, one middle caudal vertebra, fragmentary cervical ribs, one chevron missing its distal and, left scapula, and left coracoid. Reposited in the Fossil Research and Development Center of the Third Geology and Mineral Resourches Exploration Academy of Gansu Province in Lanzhou,
Type locality and horizon
Eastern part of the Lanzhou Basin, Gansu Province, P.R. China: Hekou Group, Lower Cretaceous (Edittorial Committee of Chinese Stratigraphic Standard, 2000)
Description
The allmost complete sacrum is composed of five coosified vertebrae, as in basal macronarians, but one fewer than in Euhelopus (Wiman, 1929) and more derived lithostrotians (Upchurch et al, 2004). The cylindrical sacral centra are fused; the first sacral has a flat canial articular surface and the last a concave caudal articular surface. The cranial surface of the first centrum is much wider than tall. No pleurocoels are developed on the lateral surfaces. The articular surfaces of the prezygapophyses of the first sacral face dorsally. The neaural arches of all five sacrals are, like their centra, fused, though the neural spines of only the first four sacrals are fused.
Automorphic to these fout fused neural spines (totalling 60 cm long) are their extremely short heights and markedly transversely expanded distal ends. The height of each neural spine is about 8 cm, but the widths of the expanded dorsal surfaces (along their caudal margins) begin at 20 cm on the first sacral and decrease caudally to 8 cm in the fourth sacral.
The sacral plate is composed of the transverse processes dorsally and the sacral ribs ventrally; these are fused to each other. In dorsal view, the transverse processes project laterally, but also slightly cranially in the first two sacrals and slightly caudally in the last three.
The dorsal surface of the proximal end of each transverse process is craniocaudally expanded and braced against the neural spine by the spinoprezygapophysal, spinodiapophysal and spinopostzygapophysal laminae. However the robustness of htese laminae varies in each individual sacral.
In ventral view, the sacral ribs expand at both the proximal end distal ends. The proximal ends of the first four ribs attach to the cranial portions of their respective centra via the parapophyses, while that of the fifth rib attaches to the midpoint of the centrum. Exept for the first, the distal ends of all the sacral ribs connect to each other, forming a sacrocostal yoke.
Two isolated caudals are preserved. One which has its neural arch occupying most of the length of the centrum, is much taller than the other. It is designated as a proximal caudal. In the other, the neural arch only occupies the proximal half of the length of the centrum, which is typical of the middle caudals of titanosauriforms.
The centrum of the proximal caudal is amphiplatyan, and has subcircular articular surfaces. The length of the centrum is shorter than the width of the articualr surface. The ventral side of the centrum bears a wide but shallow longitudinal fossa that is more prominent at its distal end due to the enlargement of the chevron articualr facets. The neural arch encompasses a relatively large neural canal that is about half as tall as the centrum. The medially facing prezygapophyses are transversely compressed, directed proximodorsally, and project slightly beyond the proximal end of the centrum. The postzygapophyses are mere facets, rather than processes. The neuraql spine is retangular in lateral view, projecting more dorsally than distally. No clear laminae develop arround the neural spine, as would be expected in a verry proximal caudal vertebrae, implying a relatively distal position for this element. The transverse processes are situated at the neuralcentral suture, and seem to trend caudolaterally.
The centrum of the middle caudal is also amphiplatyan. Its articular surfaces have subcircular outlines, although diagenetic deformation may obscure its actual configuration. The width of each articular surface is about the same as the length of the centrum, which is slightly longer than that of the proximal centrum. Differing from the proximal caudal, its prezygapophyses and neural spine project more horizontally than dorsally. Transverse processes still exists, indicating a relatively proximal position for the middle caudal.
Several fragmentary cervical ribs are preserved. One cervical rib is relatively complete, and measures 1.1 m long. Its proximal end is tetraradiate, with a short cranial process. The angle between the capitulum and the tuberculum is well bellow 90o, indicating a ventral placement of the rib relativelyto the ventral edge of its centrum.
A single chevron is represented by its proximal and and part of its distal portion. Based on its large size, this chevron is probably articulated with proximal caudals. The proximal end has two rami that are not bridged. The hemal canal enclosed by the two rami is deep.
The lateral side of the left scapula is prepared. This scapula is unique among all sauropods in having an extremely dorsoventrally expanded, plate-like acromion (83 cm tall), longer than the blade itself (70 cm). The plate is eliptical in outline, with its dorsal portion far larger than the ventral one. A low deltoid ridge runs along the caudodorsal edge of the acromion, and defines the caudal margin of a shallow fossa that occupies the bulk of the dorsal portion of the plate. The acromion and scapular body become thicker ventrally, expecially at the cranioventral edge of hte glenoid. As in Euhelopus and titanosaurians, the scapular portion of the glenoid faces not only cranioventrally, but also medially. The short blade of the scapula expands caudally, with a pronounched hook at its caudaldorsal corner. The lateral side of the blade is slightly convex, giving it a D-shaped cross-sectional morphology.
The left coracoid is a relatively flat plate, with round dorsal and cranial margins and sinouus caudal and ventral margins. The caudal margin is convex, with its apex at the midpoint, fittng a corresponding concavity on the cranial margin of the scapula. The coracoidal portion of the glenoid is transversely rugose and thick and bears a pronounched lip. Cranial to this, a notch embays the ventral margin of the element. A corcoid foramen is situated at mid-height, just cranial to the coracoid-scapula contact.