[D] Therizinosaurus cheloniformis [sG] [T]
Describer
Maleev, 1954
Time
Cretaceous Late ?Campanian Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Therizinosauroidea Therizinosauridae
Diet
?
Fossilsite
Nemegt Formation, Omnogov, White Beds of Khermeen Tsav, Bayankhongor, Baynshirenskaya Svita, Omnogov, Dornogov, Mongolia
Length
12 meter
Info
Genus - Typespecies
Partial forelimbs and pectoral girdles, from the Campanian of the Nemegt Basin, Mongolia. Gigantic, theropods with long forelimbs, humerus not twisted, distal carpals blocklike, manus tridactyl and metacarpals of uneven length, unguals, long and weakly curved and yet veryy narrow. Therizinosaurus cheloniformis had 2 m long front limbs with a three-fingered hand.
There is a pulley-like semilunate carpal in the wrist, and the first metacarpal is short. The laterally compressed unguals are gigantic, and the one on the first finger can be 0.7 m long. The claws on the second and third digits were shorter.
The first remains of Therizionsaurus were thought to belong to a \\\"turtle-like lizard\\\" (Maleev, 1954) and were later assigned to chelonians. It has been included with Segnosaurus, Erlikosaurus and others whitin the Therizinosauridae (Russel & Dong, 1993).
(IGM 100/15) (~9.6 m; ~6.2 tons) tooth, scapula (670 mm), coracoid (360 mm), humerus (760 mm), radius (550.4 mm), ulna (620.2 mm), semilunate carpal, distal carpal, metacarpal I (145.5 mm), metacarpal II (286.8 mm), phalanx II-1 (141.7 mm), phalanx II-2 (145.8 mm), manual ungual II (~585 mm), metacarpal III (191.6 mm), dorsal ribs, gastralia Heavier than all but a few of the largest taxa, but not as long as most. [M.Mortimer]
Barsbold, 1983
Holotype
PIN no. 551-483; three manual ungual phalanges (two of them incomplete.
Description. Scapula 670 mm long (note: the measurements here and below were made on the right forelimb elements and the anterior half of the shoulder region, which were almost completely preserved), with a highly widened ventral part, a wide acromial process, and a narrow, relatively short, and flattened dorsal blade. The posterior edge of the ventrally widened scapula is highly thickened, and the acromion is thin, apparently becoming transformed into a cartilaginous framework along its periphery. A rounded foramen is located near the anterior edge of the scapular widening and near the scapulocoracoid fissure, not noted in other theropods, through which blood vessels and nerves supposedly passed. The dorsal blade of the scapula has nearly parallel anterior and posterior edges.
The coracoid is 360 mm long, with a widened, convex external surface that forms a gently sloping concavity in the region of the scapulocoracoid fissure which turns towards the scapular widening. Along the periphery of the coracoid, especially near the scapulocoracoid fissure, this edge become very thin and possibly turns into cartilage, as is the case with the scapular edge. The coracoid foramen is large, and cuts across the bony material above the coracoid portion of the glenoid. The attachment point for the biceps muscle is marked by a large tubercle with a shortened top. The glenoid cavity is deep and wide, slightly turned externally, and has convex, thickened, crest-like edges. The supraglenoid thickening, shaped like a convex crest, is divided along the top of the scapulocoracoid fissure.
The humerus is 760 mm long, massive, and has a highly widened proximal end. The deltoid crest is tall and very thickened, and its top is located approximately one-third of the distance from the proximal end of the humerus, while the length of the crest is no less than two-thirds the length of the entire bone. The distal end of the humerus is highly widened, and flattened anteroposteriorly. The condyles are extended onto the anterior side of the distal widening.
The epicondyles are highly widened, and extend beyond the limits of the articular block surfaces. The ulna has an elongated shaft (620.2 mm) and a widened ulnar process. The proximal articular surface of the bone is divided into two parts: the lateral has a triangular outline, is limited dorsally by the fossa for the proximal end of the radius, and is slightly concave; the medial forms a semilunar fossa that covers the lunar condyle of the humerus.
The widened, thickened distal end of the ulna is inturned approximately 30° relative to the plane of the proximal end. The radius is 550.4 mm long and slightly sigmoidally curved, with a widened, laterally flattened proximal end and a massive, thickened distal end.
The carpus consists of a pulley in which two distal carpals take part. The first distal carpal is 82.3 mm tall and 85.3 mm wide, with two articular surfaces on its distal end. Medially, it is triangular in outline and adjoins the proximal surface of metacarpal I, occupying somewhat less than the lateral area, which is compressed in configuration and adjoins the articular surface of metacarpal II. The two surfaces noted above are divided by an obliquely-oriented process that is formed when they cross. The proximal surface of the first distal carpal is convex, and divided by a wide transverse fossa that forms the articular surface of the pulley trough. The lateral edge of the bone has a right-angled fenestra that closely accommodates the edge of the second distal carpal, which has a height of 56.0 mm and a width of 59.3 mm. For this, the dorsal edge of considerably thickened, while it is narrowed ventrally.
The transverse fossa is not expressed on the proximal surface of distal carpal 2. The distal surface is flattened. Upon articulation of the two carpal bones, the articular surface of the pulley continues from the first to the second. The proximal carpal bone that entered the pulley trough is not preserved. The manus is composed of three elements. Metacarpal I is 145.5 mm long, and is the shortest, highly widened, and flattened obliquely. Its lateral side is wider, particularly the proximal part, and the medial edge is very narrow. The proximal articular surface of metacarpal I has a tripartite construction.
The distal articular head is asymmetric, and turns medially from the left, with wide, deep sagittal fossae. The lateral connecting fossae are very weakly expressed. Metacarpal II is 286.8 mm long, is the most elongated and massive, and has a slanted, rectangular, flattened proximal articular surface. The articular surface of the distal head has nearly symmetrical condyles, and is divided by a wide, deep sagittal fossa. The lateral connecting fossae are very weakly expressed. Metacarpal III is 191.6 mm long, has the most slender shaft, and exhibits a tripartite proximal articular surface. The distal articular head is highly asymmetrical, with deep, wide sagittal fossae. The lateral connecting fossae are very weakly expressed. Only digit II of the right manus, consisting of three phalanges is represented completely in the collection. The basal and penultimate phalanges are subequal in length (141.7 and 143.8 mm, respectively) and shape, as well as massive and shortened.
The proximal articular surfaces are nearly symmetrical, and have a convex sagittal crest that is higher in the basal phalanx. The dorsal edge of the sagittal crest is highly protruding and thickened, and is the site for attachment of the extensor tendons. The distal heads of the phalanges are almost symmetrical, and the sagittal fossa is considerably wider and deeper in the basal phalanx compared with the penultimate one. The lateral connecting fossae are weakly expressed, forming crest-like protruding edges for the articular condyles. The ungual phalanges are of gigantic size (approximately 520 mm in length), moderately curved, very wide, highly laterally compressed, narrow in transverse cross-section, and lanceolate in outline. The distal ends are pointed (preserved in a fragment of ungual phalanx PST 100/16). The proximal articulation of the ungual phalanx is symmetrical and has a transverse ridge that divides the surface into two unequal parts, with the upper sagittal crest more convex than the lower. The dimensions of the individual ungual phalanges (PST nos. 100/16, 100/17) testify to the possibility that they belong to manual digits I and III, respectively.
Discussion
Currently finds of large ungual phalanges are known from different regions – Kazakhstan, trans-Baikal, Nigeria (Rozhdestvensky, 1970; Ricqles, 1967) – but these are almost three times smaller in length than those of Therizinosaurus. Besides this, there are more than small differences in shape and degree of curvature in corresponding phalanges. The large ungual phalanges, previously identified as belonging to the manus of Alectrosaurus (Gilmore, 1933), probably do not belong to this taxon (Perle, 1977) and, therefore, questions about the similarity of this structure in Therizinosaurus and Alectrosaurus (Rozhdestvensky, 1970) can be entirely put aside. Chilantaisaurus also has a similar, large ungual phalanx (Hu, 1964), however its differentiation from those of Therizinosaurus is very clear. The specific construction of the forelimb in Therizinosaurus testifies to the fact that it cannot be identified with Chilantaisaurus and Alectrosaurus. Until more complete materials of Therizinosaurus were found, this was considered possible (Barsbold, 1970). The discovery of several large ungual phalanges testifies towards the variety of gigantic carnivorous dinosaurs with non-reduced forelimbs, although notable different from Therizinosaurus.
Material
PST GIN AN MNR no. 100/15; right and left scapulocoracoid (left is poorly preserved), right and left humeri, right forearm and left ulna, two right distal carpals, right manus with phalanges of digit II, among them the ungual phalanx as well. Fragments of dorsal and abdominal ribs. no. 100/17; an ungual phlanx lacking the distal portion. no. 100/16; an ungual phalanx lacking the proximal portion.
Source: Polyglot Paleontologist
Maleev, 1954
Time
Cretaceous Late ?Campanian Maastrichtian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Therizinosauroidea Therizinosauridae
Diet
?
Fossilsite
Nemegt Formation, Omnogov, White Beds of Khermeen Tsav, Bayankhongor, Baynshirenskaya Svita, Omnogov, Dornogov, Mongolia
Length
12 meter
Info
Genus - Typespecies
Partial forelimbs and pectoral girdles, from the Campanian of the Nemegt Basin, Mongolia. Gigantic, theropods with long forelimbs, humerus not twisted, distal carpals blocklike, manus tridactyl and metacarpals of uneven length, unguals, long and weakly curved and yet veryy narrow. Therizinosaurus cheloniformis had 2 m long front limbs with a three-fingered hand.
There is a pulley-like semilunate carpal in the wrist, and the first metacarpal is short. The laterally compressed unguals are gigantic, and the one on the first finger can be 0.7 m long. The claws on the second and third digits were shorter.
The first remains of Therizionsaurus were thought to belong to a \\\"turtle-like lizard\\\" (Maleev, 1954) and were later assigned to chelonians. It has been included with Segnosaurus, Erlikosaurus and others whitin the Therizinosauridae (Russel & Dong, 1993).
(IGM 100/15) (~9.6 m; ~6.2 tons) tooth, scapula (670 mm), coracoid (360 mm), humerus (760 mm), radius (550.4 mm), ulna (620.2 mm), semilunate carpal, distal carpal, metacarpal I (145.5 mm), metacarpal II (286.8 mm), phalanx II-1 (141.7 mm), phalanx II-2 (145.8 mm), manual ungual II (~585 mm), metacarpal III (191.6 mm), dorsal ribs, gastralia Heavier than all but a few of the largest taxa, but not as long as most. [M.Mortimer]
Barsbold, 1983
Holotype
PIN no. 551-483; three manual ungual phalanges (two of them incomplete.
Description. Scapula 670 mm long (note: the measurements here and below were made on the right forelimb elements and the anterior half of the shoulder region, which were almost completely preserved), with a highly widened ventral part, a wide acromial process, and a narrow, relatively short, and flattened dorsal blade. The posterior edge of the ventrally widened scapula is highly thickened, and the acromion is thin, apparently becoming transformed into a cartilaginous framework along its periphery. A rounded foramen is located near the anterior edge of the scapular widening and near the scapulocoracoid fissure, not noted in other theropods, through which blood vessels and nerves supposedly passed. The dorsal blade of the scapula has nearly parallel anterior and posterior edges.
The coracoid is 360 mm long, with a widened, convex external surface that forms a gently sloping concavity in the region of the scapulocoracoid fissure which turns towards the scapular widening. Along the periphery of the coracoid, especially near the scapulocoracoid fissure, this edge become very thin and possibly turns into cartilage, as is the case with the scapular edge. The coracoid foramen is large, and cuts across the bony material above the coracoid portion of the glenoid. The attachment point for the biceps muscle is marked by a large tubercle with a shortened top. The glenoid cavity is deep and wide, slightly turned externally, and has convex, thickened, crest-like edges. The supraglenoid thickening, shaped like a convex crest, is divided along the top of the scapulocoracoid fissure.
The humerus is 760 mm long, massive, and has a highly widened proximal end. The deltoid crest is tall and very thickened, and its top is located approximately one-third of the distance from the proximal end of the humerus, while the length of the crest is no less than two-thirds the length of the entire bone. The distal end of the humerus is highly widened, and flattened anteroposteriorly. The condyles are extended onto the anterior side of the distal widening.
The epicondyles are highly widened, and extend beyond the limits of the articular block surfaces. The ulna has an elongated shaft (620.2 mm) and a widened ulnar process. The proximal articular surface of the bone is divided into two parts: the lateral has a triangular outline, is limited dorsally by the fossa for the proximal end of the radius, and is slightly concave; the medial forms a semilunar fossa that covers the lunar condyle of the humerus.
The widened, thickened distal end of the ulna is inturned approximately 30° relative to the plane of the proximal end. The radius is 550.4 mm long and slightly sigmoidally curved, with a widened, laterally flattened proximal end and a massive, thickened distal end.
The carpus consists of a pulley in which two distal carpals take part. The first distal carpal is 82.3 mm tall and 85.3 mm wide, with two articular surfaces on its distal end. Medially, it is triangular in outline and adjoins the proximal surface of metacarpal I, occupying somewhat less than the lateral area, which is compressed in configuration and adjoins the articular surface of metacarpal II. The two surfaces noted above are divided by an obliquely-oriented process that is formed when they cross. The proximal surface of the first distal carpal is convex, and divided by a wide transverse fossa that forms the articular surface of the pulley trough. The lateral edge of the bone has a right-angled fenestra that closely accommodates the edge of the second distal carpal, which has a height of 56.0 mm and a width of 59.3 mm. For this, the dorsal edge of considerably thickened, while it is narrowed ventrally.
The transverse fossa is not expressed on the proximal surface of distal carpal 2. The distal surface is flattened. Upon articulation of the two carpal bones, the articular surface of the pulley continues from the first to the second. The proximal carpal bone that entered the pulley trough is not preserved. The manus is composed of three elements. Metacarpal I is 145.5 mm long, and is the shortest, highly widened, and flattened obliquely. Its lateral side is wider, particularly the proximal part, and the medial edge is very narrow. The proximal articular surface of metacarpal I has a tripartite construction.
The distal articular head is asymmetric, and turns medially from the left, with wide, deep sagittal fossae. The lateral connecting fossae are very weakly expressed. Metacarpal II is 286.8 mm long, is the most elongated and massive, and has a slanted, rectangular, flattened proximal articular surface. The articular surface of the distal head has nearly symmetrical condyles, and is divided by a wide, deep sagittal fossa. The lateral connecting fossae are very weakly expressed. Metacarpal III is 191.6 mm long, has the most slender shaft, and exhibits a tripartite proximal articular surface. The distal articular head is highly asymmetrical, with deep, wide sagittal fossae. The lateral connecting fossae are very weakly expressed. Only digit II of the right manus, consisting of three phalanges is represented completely in the collection. The basal and penultimate phalanges are subequal in length (141.7 and 143.8 mm, respectively) and shape, as well as massive and shortened.
The proximal articular surfaces are nearly symmetrical, and have a convex sagittal crest that is higher in the basal phalanx. The dorsal edge of the sagittal crest is highly protruding and thickened, and is the site for attachment of the extensor tendons. The distal heads of the phalanges are almost symmetrical, and the sagittal fossa is considerably wider and deeper in the basal phalanx compared with the penultimate one. The lateral connecting fossae are weakly expressed, forming crest-like protruding edges for the articular condyles. The ungual phalanges are of gigantic size (approximately 520 mm in length), moderately curved, very wide, highly laterally compressed, narrow in transverse cross-section, and lanceolate in outline. The distal ends are pointed (preserved in a fragment of ungual phalanx PST 100/16). The proximal articulation of the ungual phalanx is symmetrical and has a transverse ridge that divides the surface into two unequal parts, with the upper sagittal crest more convex than the lower. The dimensions of the individual ungual phalanges (PST nos. 100/16, 100/17) testify to the possibility that they belong to manual digits I and III, respectively.
Discussion
Currently finds of large ungual phalanges are known from different regions – Kazakhstan, trans-Baikal, Nigeria (Rozhdestvensky, 1970; Ricqles, 1967) – but these are almost three times smaller in length than those of Therizinosaurus. Besides this, there are more than small differences in shape and degree of curvature in corresponding phalanges. The large ungual phalanges, previously identified as belonging to the manus of Alectrosaurus (Gilmore, 1933), probably do not belong to this taxon (Perle, 1977) and, therefore, questions about the similarity of this structure in Therizinosaurus and Alectrosaurus (Rozhdestvensky, 1970) can be entirely put aside. Chilantaisaurus also has a similar, large ungual phalanx (Hu, 1964), however its differentiation from those of Therizinosaurus is very clear. The specific construction of the forelimb in Therizinosaurus testifies to the fact that it cannot be identified with Chilantaisaurus and Alectrosaurus. Until more complete materials of Therizinosaurus were found, this was considered possible (Barsbold, 1970). The discovery of several large ungual phalanges testifies towards the variety of gigantic carnivorous dinosaurs with non-reduced forelimbs, although notable different from Therizinosaurus.
Material
PST GIN AN MNR no. 100/15; right and left scapulocoracoid (left is poorly preserved), right and left humeri, right forearm and left ulna, two right distal carpals, right manus with phalanges of digit II, among them the ungual phalanx as well. Fragments of dorsal and abdominal ribs. no. 100/17; an ungual phlanx lacking the distal portion. no. 100/16; an ungual phalanx lacking the proximal portion.
Source: Polyglot Paleontologist