Massospondylus carinatus is a basal sauropodomorph dinosaur from the early Jurassic Elliot Formation of South Africa. It is one of the best-represented fossil dinosaur taxa, known from hundreds of specimens including at least 13 complete or nearly complete skulls. Surprisingly, the internal cranial anatomy of M. carinatus has never been described using computed tomography (CT) methods. Using CT scans and 3D digital representations, we digitally reconstruct the bones of the facial skeleton, braincase, and palate of a complete, undistorted cranium of M. carinatus (BP/1/5241). We describe the anatomical features of the cranial bones, and compare them to other closely related sauropodomorph taxa such as Plateosaurus erlenbergiensis, Lufengosaurus huenei, Sarahsaurus aurifontanalis and Efraasia minor. We identify a suite of character states of the skull and braincase for M. carinatus that sets it apart from other taxa, but these remain tentative due to the lack of comparative sauropodomorph braincase descriptions in the literature. Furthermore, we hypothesize 27 new cranial characters useful for determining relationships in non-sauropodan Sauropodomorpha, delete five pre-existing characters and revise the scores of several existing cranial characters to make more explicit homology statements. All the characters that we hypothesized or revised are illustrated. Using parsimony as an optimality criterion, we then test the relationships of M. carinatus (using BP/1/5241 as a specimen-level exemplar) in our revised phylogenetic data matrix.
Figure 1: Photographs of the skull of BP/1/5241. (A) Left lateral view. (B) Right lateral view. (C) Dorsal view.
Figure 2: Reconstructed skull of BP/1/5241. (A) Left lateral view. (B) Right lateral view.
The use of CT scanning and 3D visualization graphics allows for a better understanding of the internal and external morphological structures of the braincase as well as information about the soft tissues such as the vestibular canals. M. carinatus can be tentatively diagnosed cranially by basipterygoid processes that are separated by an angle smaller than 60° and a jugal process of the ectopterygoid that is strongly curved. A revision of cranial characters provides a basis for more comparative work on the braincase of sauropodomorphs in general. Results also show a well-supported Massospondylidae clade. Further phylogenetic analyses using individual specimens of known ontogenetic stages as operational taxonomic units would provide better resolution for the Massospondylidae clade as well as a better understanding of which sets of character states set M. carinatus aside from other taxa.
Kimberley E.J. Chapelle and Jonah N. Choiniere. 2018. A Revised Cranial Description of Massospondylus carinatus Owen (Dinosauria: Sauropodomorpha) based on Computed Tomographic Scans and A Review of Cranial Characters for Basal Sauropodomorpha. PeerJ. 6:e4224. DOI: 10.7717/peerj.4224
CT-scan study makes it possible to 3-D print the skull of the dinosaur species Massospondylushttp://phy.so/434970306 via @physorg_com
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
During the latest Cretaceous, distinct dinosaur faunas were found in Laurasia and Gondwana. Tyrannosaurids, hadrosaurids, and ceratopsians dominated in North America and Asia, while abelisaurids and titanosaurids dominated in South America, India, and Madagascar. Little is known about dinosaur faunas from the latest Cretaceous of Africa, however. Here, a new abelisaurid theropod, Chenanisaurus barbaricus, is described from the upper Maastrichtian phosphates of the Ouled Abdoun Basin in Morocco, North Africa on the basis of a partial dentary and isolated teeth. Chenanisaurus is both one of the largest abelisaurids, and one of the youngest known African dinosaurs. Along with previously reported titanosaurid remains, Chenanisaurus documents the persistence of a classic Gondwanan abelisaurid-titanosaurid fauna in mainland Africa until just prior to the end-Cretaceous mass extinction. The animal is unusual both in terms of its large size and the unusually short and robust jaw. Although it resembles South American carnotaurines in having a deep, bowed mandible, phylogenetic analysis suggests that Chenanisaurus may represent a lineage of abelisaurids that is distinct from those previously described from the latest Cretaceous of South America, Indo-Madagascar, and Europe, consistent with the hypothesis that the fragmentation of Gondwana led to the evolution of endemic dinosaur faunas during the Late Cretaceous.
Abelisauridae Bonaparte and Novas (Bonaparte and Novas, 1985)
Chenanisaurus barbaricus new genus and species
Etymology. The genus name refers to the Sidi Chennane phosphate mines, the type locality, and Greek ‘sauros, ‘lizard’. The species name is derived from the Greek barbaros, “savage” or “barbaric” and also refers to Barbary, a name historically used for Morocco and the northwest coast of Africa.
Diagnosis. Large abelisaurid characterized by a proportionately deep mandible, dentary bowed in lateral view, lateral groove and associated foramina located high on dentary; anterodorsal margin of dentary downturned in lateral view; massive symphysis, with anterior margin of symphysis vertical in lateral view; tip of jaws broad, with dentaries meeting at an obtuse angle.
Holotype. OCP DEK-GE 772, anterior end of the left dentary ( Fig. 3 ; Fig. 4).
Horizon and Locality. The type specimen is reported as coming from the upper Maastrichtian (Couche III) of Sidi Chennane; the pale white color of the bone and the color of the associated matrix are consistent with the preservation seen in other material recovered from this locality. The isolated premaxillary teeth come from the upper Maastrichtian (Couche III) of Sidi Daoui. The maxillary tooth is of unknown provenance but likely comes from either Sidi Chennane or Sidi Daoui. All specimens come from the Ouled Abdoun Basin, Morocco North Africa (Fig. 1).
Fig. 9. Chenanisaurusbarbaricus shown to scale with the Couche III titanosaur.
Nicholas R. Longrich, Xabier Pereda-Suberbiola, Nour-Eddine Jalil, Fatima Khaldoune and Essaid Jourani. 2017. An Abelisaurid from the latest Cretaceous (late Maastrichtian) of Morocco, North Africa. Cretaceous Research. In Press. DOI: 10.1016/j.cretres.2017.03.021
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
The paleobiogeographic significance of continental Africa during the middle and Late Cretaceous is not well understood, in part due to incomplete sampling from large portions of the landmass during these intervals. Intensified field efforts in the Galula Formation exposed in southwestern Tanzania have revealed a diverse vertebrate fauna, including the novel titanosaurian Shingopana songwensis, gen. et sp. nov., described herein. Based on a left angular, cervical vertebrae, cervical and dorsal ribs, a left humerus, and a partial left pubis, Shingopana exhibits morphology indicating affinities with the Late Cretaceous aeolosaurine titanosaurians of South America. The bulbous expansion of the cervical vertebral neural spine is similar to the condition in Bonitasaura salgadoi, Overosaurus paradasorum, and Trigonosauruspricei. The dorsal ribs of Shingopana also present proximal anterior and posterior flanges that previously were proposed to be unique to Overosaurus. Furthermore, Shingopana is diagnosed by a divided spinoprezygapophyseal lamina in the middle-to-posterior cervical vertebrae. Parsimony and both uncalibrated and tip-dated Bayesian phylogenetic approaches support Shingopana as the first African titanosaurian that is closely related to aeolosaurines. Comparisons with other African titanosaurians, such as the co-occurring Rukwatitan bisepultus and geographically proximate Malawisaurus dixeyi, suggest that southern African forms represent diverse taxa rather than forming a monophyletic group. Moreover, southern African forms exhibit stronger affinities with South American clades than with representative northern African form, suggesting that tectonically driven separation of the two landmasses may have influenced the development of progressively isolated southern African faunas throughout the Cretaceous.
Excavation of Shingopana songwensis showing ribs and other bones being prepared for plaster-jacketing.
photo: Nancy Stevens
Reconstruction of Shingopana songwensis and the landscape in which it lived, in what is now Tanzania.
Illustration: Mark Witton, www.markwitton.com
SYSTEMATIC PALEONTOLOGY
DINOSAURIA Owen, 1842
SAURISCHIA Seeley, 1887
SAUROPODA Marsh, 1878
TITANOSAURIA Bonaparte and Coria, 1993
LITHOSTROTIA Upchurch, Barrett, and Dodson, 2004
SHINGOPANA SONGWENSIS, gen. et sp. nov.
Etymology—Shingopana, ‘shingo’ is the Kiswahili word for neck and ‘pana’ is the Kiswahili word for wide, in reference to the bulbous expansion of the neural spine exhibited by the wellpreserved cervical vertebra A. The Latinized specific epithet, songwensis, refers to the Songwe area and geologic sub-basin of southwestern Tanzania from which the type specimen was recovered.
....
Wide shot of the southwestern Tanzania locality from which the new dinosaur was excavated.
photo: Eric Roberts
Eric Gorscak, Patrick M. O'Connor, Eric M. Roberts and Nancy J. Stevens. 2017. The Second Titanosaurian (Dinosauria: Sauropoda) from the middle Cretaceous Galula Formation, southwestern Tanzania, with Remarks on African Titanosaurian Diversity. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1343250
Meet the new #dinosaur, Shingopana songwensis, discovered by #NSFfunded scientists working in Tanzania: @NSF
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
The Early Cretaceous of North Africa has Spinosaurinae dinosaur remains such as Spinosaurus recorded in Algeria (Guir Basin, Kem Kem beds), Egypt (Bahariya Formation), Morocco (Kem Kem beds), and Tunisia (Ain El Guettar Formation). Until now, three possible Spinosaurus species were identified: Spinosaurus aegyptiacus, Spinosaurus sp. and Spinosaurus “B”. The occurrence of this genus in the Albian-Cenomanian rocks of Africa suggests that the temporal and geographic distribution of these spinosaurines is the largest one among all genera and species of megapredators from the middle Cretaceous of Africa. The fossil record of Spinosaurus from the Albian to the Cenomanian shows a 20 million year persistence of this genus in Gondwanan ecosystems.
Keywords: theropod dinosaur, distribution, Early Cretaceous, Africa
Fig. 3 Most complete Spinosaurus species skulls from early Late Cretaceous formations from Northern Africa. Spinosaurus aegyptiacus (from Stromer, 1915), BSP 1912 – dentary, A in lateral and B in dorsal views. Spinosaurus cf. aegyptiacus (from Buffetaut and Ouaja, 2002), BM231 – rostral part of left dentary, C, in lateral and in D dorsal views. Spinosaurus marrocanus (nomen dubium) (Taquet and Russell, 1998) MNHM SAM 124 – left maxilary, E in lateral and F dorsal views. Spinosaurus cf. S. aegyptiacus (from Dal Sasso et al., 2005) MSNM V4047 – left maxilary, G in lateral in dorsal view.
Fig. 5. Semi-aquatic paleoenvironmental reconstruction of Spinosaurus dinosaur during early Late Cretaceous: (A) Spinosaurus; (B) Mawsonia coelacanth fishes; (C) Araripemys turtle (drawing Luciano Vidal).
Remarks:
The middle Cretaceous strata of North Africa preserved an important record of the theropod Spinosaurus. Although their fossil remains are usually fragmented, most specimens show diagnostic characters of the genus Spinosaurus that are especially present in their conical and non-serrated teeth. The fossil record of this genus in North Africa shows a restricted geographic distribution between the Albian and the Cenomanian periods. Yet, when we consider their temporal distribution, it suggests that Spinosaurus had a significant geological history of nearly 20 million years, a lifespan unknown for other African megapredators species (e.g., Carcharodontosaurus – 18.5 mya [Candeiro et al., 2018]). The geological evidences indicate that Africa was an island during the main period of occurrence of this genus. The faunal composition of the spinosaurinae that inhabited the eastern coast of Africa is broadly comparable with the Cenomanian fossil records from western Africa, supporting the relative homogeneous composition of the taxon in these areas during this period. Additional studies and future field prospections in other localities could eventually reveal a wider distribution of this genus in other regions of Africa (e.g., Niger, Sudan) or even in western Europe and northern South America.
Carlos Roberto A. Candeiro, Lívia Motta Gil and Pedro Ernesto Pontes de Castro. 2018. Large-sized Theropod Spinosaurus: An Important Component of the Carnivorous Dinosaur Fauna in southern Continents During the Cretaceous. Bulletin de la Société Géologique de France. 189 (4-6): 15. DOI: 10.1051/bsgf/2018010
Résumé – Spinosaurus (théropode de grande taille) : une composante importante de la faune de dinosaures carnivores des continents méridionaux au cours du Crétacé. Le Crétacé inférieur d’Afrique du Nord renferme des restes de dinosaures spinosaurinés, tels que Spinosaurus répertorié en Algérie (Bassin du Guir, Kem Kem beds), en Égypte (Formation Bahariya), au Maroc (Kem Kem beds) et en Tunisie (Formation Ain El Guettar). Jusqu’à ce jour, trois espèces de spinosaure sont reconnues : Spinosaurus aegyptiacus, Spinosaurus sp. et Spinosaurus “B”. La présence de ce genre dans les terrains albocénomaniens d’Afrique suggère que la répartition temporelle et géographique de ces spinosaurinés est la plus étendue de tous les genres et espèces de méga-prédateurs du Crétacé moyen d’Afrique. Le registre fossile de Spinosaurus, depuis l’Albien jusqu’au Cénomanien, indique une présence de 20 millions d’années pour ce genre dans les écosystèmes gondwaniens.
Mots clés : théropode dinosaure / distribution / Crétacé inférieur / Afrique
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
The African terrestrial fossil record has been limited in its contribution to our understanding of both regional and global Cretaceous paleobiogeography, an interval of significant geologic and macroevolutionary change. A common component in Cretaceous African faunas, titanosaurian sauropods diversified into one of the most specious groups of dinosaurs worldwide. Here we describe the new titanosaurian Mnyamawamtuka moyowamkia gen. et sp. nov. from the Mtuka Member of the Galula Formation in southwest Tanzania. The new specimen preserves teeth, elements from all regions of the postcranial axial skeleton, parts of both appendicular girdles, and portions of both limbs including a complete metatarsus. Unique traits of M. moyowamkia include the lack of an interpostzygapophyseal lamina in posterior dorsal vertebrae, pronounced posterolateral expansion of middle caudal centra, and an unusually small sternal plate. Phylogenetic analyses consistently place M. moyowamkia as either a close relative to lithostrotian titanosaurians (e.g., parsimony, uncalibrated Bayesian analyses) or as a lithostrotian and sister taxon to Malawisaurus dixeyi from the nearby Aptian? Dinosaur Beds of Malawi (e.g., tip-dating Bayesian analyses). M. moyowamkia shares a few features with M. dixeyi, including semi-spatulate teeth and a median lamina between the neural canal and interpostzygapophyseal lamina in anterior dorsal vertebrae. Both comparative morphology and phylogenetic analyses support Mnyamawamtuka as a distinct and distant relative to Rukwatitan bisepultus and Shingopanasongwensis from the younger Namba Member of the Galula Formation with these results largely congruent with newly constrained ages for the Mtuka Member (Aptian–Cenomanian) and Namba Member (Campanian). Coupled with recent discoveries from the Dahkla Oasis, Egypt (e.g., Mansourasaurus shahinae) and other parts of continental Afro-Arabia, the Tanzania titanosaurians refine perspectives on the development of African terrestrial faunas throughout the Cretaceous—a critical step in understanding non-marine paleobiogeographic patterns of Africa that have remained elusive until the past few years.
Systematic paleontology
DINOSAURIA
SAURISCHIA
SAUROPODA
TITANOSAURIFORMES
TITANOSAURIA
LITHOSTROTIA
MNYAMAWAMTUKA MOYOWAMKIA, gen. et sp. nov.
Etymology: Mnyamawamtuka (Mm-nya-ma-wah-mm-too-ka), ‘mnyama’ is the Kiswahili word for ‘animal’ or ‘beast’ and acts as a conceptual proxy to the titans in Titanosauria, and ‘wa Mtuka' is Kiswahili for ‘of the Mtuka’ in reference to the river drainage that yielded the type specimen. Moyowamkia (Mm-oh-yo-wa-mm-key-ah), ‘moyo’ is the Kiswahili word for heart and ‘wa mkia’ is Kiswahili for ‘of the tail’, in reference to the posterolateral expansion of the posterior centrum on the middle caudal vertebrae that gives the posterior centrum surface a heart-shape outline.
Holotype: RRBP 05834, a partial skeleton including an anterior cervical vertebral neural arch and four cervical vertebral centra, seven partial dorsal vertebrae, a sacral neural arch, three partial sacral centra, three sacral ribs, seven caudal vertebral neural arches and seven centra, four chevrons, numerous dorsal rib fragments, a right scapula, a right sternal plate, a partial left humerus and distal right humerus, partial left ulna, right metacarpal I and left metacarpal III, a partial left ischium, a partial right pubis, partial left and right femora, left tibia and partial right tibia, a left fibula, left metatarsal I, left metatarsal II, right metatarsal III, left metatarsal IV, left metatarsal V, two pedal phalanges, a left ungual, and numerous unidentifiable fragments. The majority of the fossils were prepared at the Ohio University Fossil Preparation Facility, with some of the first-discovered elements prepared by J. P. Cavigelli. Preperation used standard manual and technical techniques including hand tools and pneumatic air scribes. Repository information of RRBP 05834 is the Rukwa Rift Basin Project, Tanzanian Antiquities Unit, Dar es Salaam, Tanzania. The fossils are, at time of publication, on temporary loan and deposited at Ohio University in Athens, Ohio. All of the fossils are accessible by request. Research casts will permanently be housed at Ohio University and in the collections at Denver Museum of Science and Nature.
Fig 1. Map of research area. Map of Africa, A, with expanded regional map of the Rukwa Rift Basin of Tanzania, B, with the type localities of Mnyamawamtuka moyowamkia and Rukwatitan bisepultus quarry near the Galula study area, C, and the Shingopana songwensis quarry near the Nsungwe study area, D. Malawi Dinosaur Beds (DB) marked in B to demonstrate the proximity of the deposits to the Galula Formation.
Fig 2. Quarry map of the Mtuka bonebed locality RRBP 2004–06. Recovered elements of Mnyamawamtuka moyowamkia are color-coded and separated by dashed lines according to the year they were collected. The quarry map is represented as a four-by-six-meter grid. Unmarked elements on the map are either fragments or unidentified.
Type locality and horizon: The specimen was recovered in the Mtuka Member of the Cretaceous Galula Formation. The Mtuka Member is dominated by coarse sandstone fluvial deposits and abundant overbank siltstone and mudstone lenses within an extensive fluvial braidplain system. The holotype of M. moyowamkia was recovered from a quarry developed along the Mtuka River drainage in southwestern Tanzania (Fig 1). The quarry is roughly 20 kilometers south of Lake Rukwa near the coordinates of 32° 34’ E and 8° 34’ S. The initial discovery was made in 2004 at locality RRBP 2004–06, with additional elements recovered sequentially during the 2005–2008 field seasons by the Rukwa Rift Basin Project field teams (Fig 2). Generally, larger and more complete elements, such as appendicular remains, were recovered in the western part of the quarry whereas smaller and more fragmented elements were recovered from the eastern part of the quarry, indicating short-distance transport (Fig 2). Excavation permits were issued by The United Republic of Tanzania, Ministry of Natural Resources and Tourism, Antiquities Unit, P.O. Box 2280, Dar es Salaam, Tanzania to P. M. O’Connor under the specific permit numbers: 14–2004; EA 402/605/01; EA 402/605/01/78; EA 402/605/01/20; and EA 402/604/01/7. In a broader context, the M. moyowamkia discovery and excavation was made in the early years of the Rukwa Rift Basin Project with the aim of addressing the paucity of fossils recovered from the Cretaceous of sub-Saharan Africa.
Age and distribution: The materials were recovered from the Mtuka Member of the Galula Formation of the Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania. Based on previous lines of evidence, including faunal data within the overlying Namba Member, the age of the Galula Formation was best constrained to the middle Cretaceous (Aptian–Cenomanian) with potential dates of 100–110 Ma. However, new paleomagnetic data place the Mtuka Member (i.e., the specific unit from which M. moyowamkia was recovered) within the Cretaceous long normal with estimates of Aptian–Cenomanian for the unit and a younger date for the overlying Namba Member as either Campanian or Cenomanian–Santonian.
Fig 3. Teeth associated with Mnyamawamtuka moyowamkia skeleton. Teeth recovered from the Mnyamawamtuka moyowamkia quarry. A–D, tooth Morph A; E–F, tooth Morph B; and G–J, tooth Morph C. A, G, distal; B, E, H, labial; C, I, mesial; D, J, lingual; and F, occlusal views. Abbreviations: labwf, labial wear facet; linwf, lingual wear facet. Scale bar equals 1 cm.
Diagnosis:
...
Mnyamawamtuka moyowamkia is diagnosed by the following suite of autapomorphies: (1) middle and posterior dorsal vertebrae with vertical lamina between neural canal and interprezygapophyseal lamina that bifurcates dorsally; (2) posterior dorsal vertebra with no interpostzygapophyseal lamina as the postspinal lamina continues to the dorsal margin of the neural canal; (3) prominent dorsolateral expansion on the posterior centrum of the middle caudal vertebra; (4) curved crest with accompanying fossa within the dorsomedial region of the proximal scapular blade; (5) sternal plate unusually small, estimated to be, at most, 42% of humerus length.
....
Eric Gorscak and Patrick M. O’Connor. 2019. A New African Titanosaurian Sauropod Dinosaur from the middle Cretaceous Galula Formation (Mtuka Member), Rukwa Rift Basin, Southwestern Tanzania. PLoS ONE. 14(2): e0211412. DOI: 10.1371/journal.pone.0211412
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
Size-comparison of selected Spinosaurus individuals from the Kem Kem Beds: MSNM V6894 (B, this paper), the neotype FSAC-KK18888 (C) and the largest known individual MSNM V4047 (D), compared with Homo (1.75 m tall).
We describe a nearly complete pedal ungual phalanx, discovered in the Kem Kem Beds (Cenomanian) of Tafilalt region, south-eastern Morocco. The bone is symmetric, pointed, low, elongate, and almost flat ventrally in lateral aspect. This peculiar morphology allows to refer the specimen to the smallest known individual of the genus Spinosaurus. The bone belongs to an early juvenile individual and it is proportionally identical to the ungual of the third digit of a large partial skeleton recently found, suggesting an isometric growth for this part of the pes and the retention of peculiar locomotor adaptations—such as traversing soft substrates or paddling—during the entire lifespan.
Figure 3: Anatomical and size comparisons. Specimen MSNM V6894 in dorsal view, compared to a cast of the right ungual III-4 of specimen FSAC-KK18888 (A).
Size-comparison of selected Spinosaurus individuals from the Kem Kem Beds: MSNM V6894 (B, this paper), the neotype FSAC-KK18888 (C) and the largest known individual MSNM V4047 (D), compared with Homo (1.75 m tall).
Drawing by Marco Auditore and Prehistoric Minds, used with their permission. Scale bar equals 20 mm in A. Photos by M. Zilioli and C. Dal Sasso, used with their permission.
Systematic Palaeontology
DINOSAURIA Owen, 1842
THEROPODA Marsh, 1881
SPINOSAURIDAE Stromer, 1915
SPINOSAURUS Stromer, 1915
cf. Spinosaurus aegyptiacus Stromer, 1915
MSNM V6894 strongly resembles the pedal ungual phalanges associated to diagnosable skeletal remains of specimen FSAC-KK18888, described by Ibrahim et al. (2014) and defined as the neotype of S. aegyptiacus. MSNM V6894 shares with FSAC-KK18888 the following diagnostic characters: pedal unguals with flat plantar surface; pedal unguals broader than deep with length almost four times of the proximal depth. The overall morphology, proportions, and pattern of furrows are also very similar (see “Description and comparisons”). Following Ibrahim et al. (2014) we refer the ungual MSNM V6894 to cf. S. aegyptiacus. The variability found in cervicodorsal vertebrae (Evers et al., 2015) and quadrates (Hendrickx, Mateus & Buffetaut, 2016) might indicate a higher diversity among the spinosaurid material from the Albian–Cenomanian of North Africa than previously recognized. This proportional and morphological diversity may be related to individual variability or sexual dimorphism, or it could be above the species level. However, taking into account the low number of the known specimens, their low degree of completeness, their apparently strict taxonomic affinities, their occurrence in the same strata (or, more often, their uncertain stratigraphic provenance), and all the difficulties and controversies in investigating these aspects and, ultimately, in defining a species in palaeontology, we prefer to regard all the spinosaurid material (including pedal unguals) from the Kem Kem Beds as belonging to cf. S. aegyptiacus, pending more complete, articulated remains and reliable geological data. Further comments on this topic are beyond the purpose of this paper.
Locality: MSNM V6894 comes from some kilometers south of Erfoud, between the villages of Taouz and Begaa, Errachidia Province, Morocco (Fig. 1).
Horizon: Kem Kem Beds, Cenomanian, Upper Cretaceous (Sereno et al., 1996). The specimen was collected by G. Pasini (2008, personal communication) together with rostral teeth of the Aptian–Cenomanian elasmobranch Onchopristis sp. (Rage & Cappetta, 2002; Russell, 1996).
Conclusion
The specimen described here improves the knowledge about the appendicular skeleton of the spinosaurid theropods from the Kem Kem Beds (Late Cretaceous of Morocco) published by Ibrahim et al. (2014).
The new material indicates that the pedal ungual phalanges of Spinosaurus grew with isometry and it documents the smallest individual referable to Spinosaurus, a genus/taxon usually indicated as the longest if not the largest theropod dinosaur (Dal Sasso et al., 2005). The specimen FSAC-KK18888, with an estimated body length of 11 m, has an ungual phalanx of digit III that is 130 mm long. Assuming isometry—although isometrical scaling of the other parts of the spinosaur hind limb skeleton shown in Fig. 3 must be considered as tentative—the 21 mm long ungual MSNM V6894 would pertain to an early juvenile individual, 1.78 m long (Figs. 3B–3D), that is half the estimated length of the smallest Spinosaurus published up to date, represented by the isolated quadrate MNHN KK374 (Hendrickx, Mateus & Buffetaut, 2016).
According to Ibrahim et al. (2014), the unguals in Spinosaurus are reminiscent of the flattened pedal unguals of shorebirds that do not perch (Manegold, 2006), and the whole foot may have been adapted to traversing soft substrates or webbed for paddling. We agree with this hypothesis although it needs to be tested in the future based on more complete fossil remains and biomechanical analyses. The isolated tiny ungual here referred to a small, early juvenile of Spinosaurus indicates that the pes had the same locomotor adaptations observed in large individuals, that were probably achieved early in ontogeny and retained for the entire lifespan.
Simone Maganuco and Cristiano Dal Sasso. 2018. The Smallest Biggest Theropod Dinosaur: A Tiny Pedal Ungual of A Juvenile Spinosaurus from the Cretaceous of Morocco. PeerJ. 6:e4785. DOI: 10.7717/peerj.4785
كيف تحصل على مدونة جاهزة بآلاف المواضيع والمشاركات من هنا
شاهد قناة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على اليوتيوب لمزيد من الشرح من هنا
رابط مدونة منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات في أي وقت حــــتى لو تم حذفها من هنا شاهد صفحة منتدى مدونات بلوجر جاهزة بألاف المواضيع والمشاركات على الفيس بوك لمزيد من الشرح من هنا
تعرف على ترتيب مواضيع منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات (حتى لا تختلط عليك الامور) من هنا
ملاحظة هامة: كل عمليات تنزيل، رفع، وتعديل المواضيع الجاهزة تتم بطريقة آلية، ونعتذر عن اي موضوع مخالف او مخل بالحياء مرفوع بالمدونات الجاهزة بآلاف المواضيع والمشاركات، ولكم ان تقوموا بحذف هذه المواضيع والمشاركات والطريقة بسيطة وسهلة. ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــسلامـ.
