[Paleontology • 2018] Diluvicursor pickeringi • A New Small-bodied Ornithopod (Dinosauria, Ornithischia) from A Deep, High-energy Early Cretaceous River of the Australian–Antarctic Rift System ---ScRaBBlE

Diluvicursor pickeringi

Herne​, Tait, Weisbecker, Hall, Nair, Cleeland & Salisbury, 2018

Artwork by P. Trusler.  DOI: 10.7717/peerj.4113 

Abstract

A new small-bodied ornithopod dinosaur, Diluvicursor pickeringi, gen. et sp. nov., is named from the lower Albian of the Eumeralla Formation in southeastern Australia and helps shed new light on the anatomy and diversity of Gondwanan ornithopods. Comprising an almost complete tail and partial lower right hindlimb, the holotype (NMV P221080) was deposited as a carcass or body-part in a log-filled scour near the base of a deep, high-energy river that incised a faunally rich, substantially forested riverine floodplain within the Australian–Antarctic rift graben. The deposit is termed the ‘Eric the Red West Sandstone.’ The holotype, interpreted as an older juvenile ∼1.2 m in total length, appears to have endured antemortem trauma to the pes. A referred, isolated posterior caudal vertebra (NMV P229456) from the holotype locality, suggests D. pickeringi grew to at least 2.3 m in length. D. pickeringi is characterised by 10 potential autapomorphies, among which dorsoventrally low neural arches and transversely broad caudal ribs on the anterior-most caudal vertebrae are a visually defining combination of features. These features suggest D. pickeringi had robust anterior caudal musculature and strong locomotor abilities. Another isolated anterior caudal vertebra (NMV P228342) from the same deposit, suggests that the fossil assemblage hosts at least two ornithopod taxa. D. pickeringi and two stratigraphically younger, indeterminate Eumeralla Formation ornithopods from Dinosaur Cove, NMV P185992/P185993 and NMV P186047, are closely related. However, the tail of D. pickeringi is far shorter than that of NMV P185992/P185993 and its pes more robust than that of NMV P186047. Preliminary cladistic analysis, utilising three existing datasets, failed to resolve D. pickeringi beyond a large polytomy of Ornithopoda. However, qualitative assessment of shared anatomical features suggest that the Eumeralla Formation ornithopods, South American Anabisetia saldiviai and Gasparinisaura cincosaltensis, Afro-Laurasian dryosaurids and possibly Antarctic Morrosaurus antarcticus share a close phylogenetic progenitor. Future phylogenetic analysis with improved data on Australian ornithopods will help to test these suggested affinities.

Systematic Palaeontology

ORNITHISCHIA Seeley, 1888

CERAPODA Sereno, 1986

ORNITHOPODA Marsh, 1881

Figure 6: Partial postcranium, NMV P221080, assigned to the holotype of Diluvicursor pickeringi gen. et sp. nov., as prepared on five blocks of ETRW Sandstone. (A) Specimen viewed from above, normal to the bedding. (B) Schematic.

Abbreviations: as, astragalus; B #, host block number; Ca #, designated caudal vertebra and position; cal, calcaneum; fib, fibula; ha #, haemal arch/process and position; pd #, pedal digit number; tib, tibia. Image of NMV P221080, courtesy S. Poropat and Museums Victoria.

Figure 7: Diluvicursor pickeringi gen. et sp. nov. holotype (NMV P221080), schematic restoration in left lateral view, showing preserved bones (light shading) and incomplete caudal vertebrae (outlined). 

Abbreviations: as, astragalus; Ca #, designated caudal vertebral position; pd #, pedal digit number; tib, tibia.

Diluvicursor gen. nov.  

Etymology: From the Latin ‘diluvi,’ for deluge or flood, in reference to the deep high-energy palaeo-river within which the type material was deposited and the palaeo-floodplain upon which the river extended, combined with the suffix ‘-cursor,’ from the Latin for runner.

Diagnosis: A turkey- to rhea-sized small-bodied ornithopod, differentiated from all other ornithopods by 10 potential autapomorphies: (1) dorsoventral height of the neural arch on the anterior-most caudal vertebrae (indicated at Ca 3), highly reduced and sub-equal to dorsoventral centrum height; (2) proximodistal length of the spinal process on the anterior caudal vertebrae (Ca 3–6), highly reduced and sub-equal to anteroposterior centrum length; (3) prezygapophysis on the anterior-most caudal vertebrae (up to Ca 5), horizontally oriented and located at the neural arch base, lateral to the neural canal; (4) tuberous process dorsally on the spinoprezygapophyseal lamina (sprl) of the anterior-most caudal vertebrae; (5) dorsoventrally narrowest part of the centrum on the posterior caudal vertebrae, distinctly offset posteriorly and embayed by a sulcus; (6) deep haemal groove present on all posterior caudal vertebrae; (7) triangular intervertebral process anteriorly on the centrum of the posterior-most caudal vertebrae incises a V-shaped notch at the posterior end of the adjoining centrum; (8) caudal ribs on the anterior-most caudal vertebrae (indicated at Ca 3) are transversely broad with the distance across the ribs ∼85% of total vertebral height (inclusive of haemal arch); (9) lateral distal tarsal embayed anteriorly by a sulcus for the calcaneum; and (10) pd IV-1 is strongly asymmetrical in dorsoplantar view (the proximal cotyle flares medially and the lateral edge is straight).

Diluvicursor pickeringi sp. nov.   

2009 Ornithopoda; Rich et al., p. 677.

2014 Ornithopoda; Herne, pp. 246–274.

Derivation of name: To acknowledge the significant contribution of David A. Pickering to Australian palaeontology and in memory of his passing during the production of this work.

Distribution: Lower Cretaceous Australia.

Locality: Eric the Red West, ETRW Sandstone, lower Albian, Eumeralla Formation, Otway Group, southern Victoria.

Figure 36: Artist’s interpretation of the early Albian, volcaniclastic, floodplain palaeoenvironment within the Australian-Antarctic rift graben, in the region of Eric the Red West.
Scene depicting two individuals of Diluvicursor pickeringi on the cutbank of a high-energy meandering river, regional floral components and distant rift margin uplands. Floral components potentially included forest trees of Araucariaceae (Agathis and Araucaria), Podocarpaceae and Cupressaceae and lower story/ground cover plants, including pteridophytes (ferns, including equisetaleans), hepatics, lycopods, cycadophytes, bennettitaleans, seed-bearing fern- or cycad-like taeniopterids and early Australian angiosperms.

 Artwork by P. Trusler.

Conclusion

Diluvicursor pickeringi nov. gen. et sp. is a new small-bodied ornithopod from the lower Albian of the Eumeralla Formation in the Otway Basin. The taxon is known from an almost complete tail and lower partial right limb of the holotype (NMV P221080), as well as an isolated posterior caudal vertebra (NMV P229456), discovered at the fossil locality of Eric the Red West (ETRW). The deposit, termed the ETRW Sandstone, is interpreted to have been a broad (∼600 m), deep (∼25 m), high-energy meandering river. Sediments and fossils from the ETRW Sandstone indicate that D. pickeringi inhabited a faunally rich, substantially forested riverine floodplain within the Australian–Antarctic rift complex. A further isolated caudal vertebra from the deposit (NMV P228342), interpreted as that of an indeterminate ornithischian, suggests the locality may have hosted at least two small-bodied ornithischians. D. pickeringi grew to at least 2.3 m in length and is characterised by 10 potential autapomorphies, among which, the combination of dorsoventrally low neural arches and transversely broad caudal ribs on the anterior-most caudal vertebrae present a visually defining combination of features.

Features of the caudal vertebrae and pes suggest that D. pickeringi and the two stratigraphically younger, indeterminate ornithopods from Dinosaur Cove, NMV P185992/P185993 and NMV P186047, are closely related. However, D. pickeringi differs from NMV P185992/P185993 by having a far shorter tail (50 vertebrae compared to >71) and from NMV P186047 by having a comparatively shorter, more robust, pes. The phylogenetic position of D. pickeringi investigated through searches within three recently published datasets was unresolved beyond placement within a polytomous clade of non-iguanodontian ornithopods. Various features of the caudal vertebrae and pes suggest that the Eumeralla Formation ornithopods Diluvicursor, NMV P185992/P185993 and NMV P186047 may be more closely related to the Argentinean ornithopods Anabisetia and Gasparinisaura, the Antarctic ornithopod Morrosaurus and possibly Afro-Laurasian dryosaurids, than all other ornithopods. A common progenitor of these taxa is suggested. However, these suggested affinities are to be tested more rigorously within a revised cladistic dataset of Gondwanan ornithopods.

The discovery of D. pickeringi in the ETRW Sandstone indicates that future prospecting efforts in the Eumeralla Formation at locations where coarse, gritty sediments crop-out at the base of deep palaeoriver channels, could lead to significant new discoveries (see also Rich et al., 2009b). The articulated postcrania of similarly sized, but anatomically differing small-bodied ornithopods from the Eumeralla Formation provide unique fossil material for future comparative investigations on dinosaur biomechanics, and how differing locomotor abilities could relate to differing palaeoecosystems.

Matthew C. Herne​, Alan M. Tait, Vera Weisbecker, Michael Hall, Jay P. Nair, Michael Cleeland and Steven W. Salisbury. 2018. A New Small-bodied Ornithopod (Dinosauria, Ornithischia) from A Deep, High-energy Early Cretaceous River of the Australian–Antarctic Rift System.  PeerJ. 5:e4113.  DOI: 10.7717/peerj.4113

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

او

من هنا

شاهد هذا الفيديو القصير لطريقة التحميل البسيطة

منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات

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.

[Paleontology • 2017] Reappraisal of Austrosaurus mckillopi Longman, 1933 from the Allaru Mudstone of Queensland, Australia’s First Named Cretaceous Sauropod Dinosaur ---ScRaBBlE

Reconstruction of the possible sequence of events that led to the preservation of the carcass of the sauropod Austrosaurus mckillopi in the Eromanga Sea.
(A) Austrosaurus as a living animal on land; (B) freshly deceased Austrosaurus prior to bloating; (C) bloated Austrosaurus carcass washed out to sea, where it was possibly scavenged by marine reptiles like Kronosaurus; (D) the partially defleshed but still effectively intact thoracic portion of the Austrosaurus carcass is picked at by sharks as it sinks to the seafloor; (E) the thoracic portion of the Austrosaurus carcass is buried along with several ammonites (Beudanticeras) and bivalves (Inoceramus), which were possibly drawn to the carcass as it decayed.

Reconstruction by Travis R. Tischler.

 Poropat, Nair, Syme, et al. 2017. Reappraisal of Austrosaurus mckillopi Longman, 1933. ... DOI: 10.1080/03115518.2017.1334826

Austrosaurus mckillopi was the first Cretaceous sauropod reported from Australia, and the first Cretaceous dinosaur reported from Queensland (northeast Australia). This sauropod taxon was established on the basis of several fragmentary presacral vertebrae (QM F2316) derived from the uppermost Lower Cretaceous (upper Albian) Allaru Mudstone, at a locality situated 77 km west-northwest of Richmond, Queensland. Prior to its rediscovery in 2014, the type site was considered lost after failed attempts to relocate it in the 1970s. Excavations at the site in 2014 and 2015 led to the recovery of several partial dorsal ribs and fragments of presacral vertebrae, all of which clearly pertained to a single sauropod dinosaur. The discovery of new material of the type individual of Austrosaurus mckillopi, in tandem with a reassessment of the material collected in the 1930s, has facilitated the rearticulation of the specimen. The resultant vertebral series comprises six presacral vertebrae—the posteriormost cervical and five anteriormost dorsals—in association with five left dorsal ribs and one right one. The fragmentary nature of the type specimen has historically hindered assessments of the phylogenetic affinities of Austrosaurus, as has the fact that these evaluations were often based on a subset of the type material. The reappraisal of the type series of Austrosaurus presented herein, on the basis of both external morphology and internal morphology visualized through CT data, validates it as a diagnostic titanosauriform taxon, tentatively placed in Somphospondyli, and characterized by the possession of an accessory lateral pneumatic foramen on dorsal vertebra I (a feature that appears to be autapomorphic) and by the presence of a robust ventral mid-line ridge on the centra of dorsal vertebrae I and II. The interpretation of the anteriormost preserved vertebra in Austrosaurus as a posterior cervical has also prompted the re-evaluation of an isolated, partial, posterior cervical vertebra (QM F6142, the ‘Hughenden sauropod’) from the upper Albian Toolebuc Formation (which underlies the Allaru Mudstone). Although this vertebra preserves an apparent unique character of its own (a spinopostzygapophyseal lamina fossa), it is not able to be referred unequivocally to Austrosaurus and is retained as Titanosauriformes indet. Austrosaurus mckillopi is one of the oldest known sauropods from the Australian Cretaceous based on skeletal remains and potentially provides phylogenetic and/or palaeobiogeographic context for later taxa such as Wintonotitan wattsi, Diamantinasaurus matildae and Savannasaurus elliottorum.

Fig. 11. Reconstruction of the possible sequence of events that led to the preservation of the carcass of the sauropod Austrosaurus mckillopi in the Eromanga Sea. (A) Austrosaurus as a living animal on land; (B) freshly deceased Austrosaurus prior to bloating; (C) bloated Austrosaurus carcass washed out to sea, where it was possibly scavenged by marine reptiles like Kronosaurus; (D) the partially defleshed but still effectively intact thoracic portion of the Austrosaurus carcass is picked at by sharks as it sinks to the seafloor; (E) the thoracic portion of the Austrosaurus carcass is buried along with several ammonites (Beudanticeras) and bivalves (Inoceramus), which were possibly drawn to the carcass as it decayed.

Reconstruction by Travis R. Tischler. 

Conclusion: 

The sauropod taxon Austrosaurus mckillopi is of historical significance to Australian palaeontology as the first Cretaceous dinosaur recognized in Queensland, and the first Cretaceous sauropod ever reported from the entire continent. The augmentation, articulation and description of the type material have helped to shed light on the phylogenetic position of Austrosaurus, unequivocally placing it within Titanosauriformes, and probably as a member of Somphospondyli. The identification of an autapomorphic auxiliary pneumatic foramen in dorsal vertebra I means that the referral of other sauropod specimens to Austrosaurus should be possible in the future, although this feature is not presently observable in any other Australian sauropod specimen. The morphological congruence of the posteriormost cervical vertebra of Austrosaurus with QM F6142 (the ‘Hughenden sauropod’) might represent grounds for the referral of the latter to the former, although this can not be demonstrated unequivocally. Lastly, despite its fragmentary nature, Austrosaurus appears to share several features with the type specimens of both Diamantinasaurus and Savannasaurus, possibly indicating a close phylogenetic relationship.

The fragmentary nature of the type series of Austrosaurus has impeded, and will continue to restrict, efforts to precisely resolve its phylogenetic position within Titanosauriformes. Consequently, the palaeobiogeographic significance of Austrosaurus is poorly understood, a situation worsened by the relative rarity of Early Cretaceous titanosauriforms in South America and the lack of such in Antarctica. Nevertheless, the presence of numerous titanosauriform lineages in the Early Cretaceous of South America provides some context for Australian Early Cretaceous titanosauriforms like Austrosaurus, and also for the mid-Cretaceous Winton Formation fauna, which appears to have been dominated by titanosaurs with amphicoelous (rather than procoelous) caudal vertebrae.

Stephen F. Poropat, Jay P. Nair, Caitlin E. Syme, Philip D. Mannion, Paul Upchurch, Scott A. Hocknull,  Alex G. Cook, Travis R. Tischler and Timothy Holland. 2017. Reappraisal of Austrosaurus mckillopi Longman, 1933 from the Allaru Mudstone of Queensland, Australia’s First Named Cretaceous Sauropod Dinosaur. Alcheringa: An Australasian Journal of Palaeontology. DOI: 10.1080/03115518.2017.1334826

twitter.com/taphovenatrix/status/890381395851304960/photo

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

من هنا

او

من هنا

شاهد هذا الفيديو القصير لطريقة التحميل البسيطة

منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات

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.

[Paleontology • 2019] Galleonosaurus dorisae • New Small-bodied Ornithopods (Dinosauria, Neornithischia) from the Early Cretaceous Wonthaggi Formation (Strzelecki Group) of the Australian-Antarctic Rift System, with Revision of Qantassaurus intrepidus ---ScRaBBlE

Galleonosaurus dorisae 

Herne, Nair, Evans & Tait, 2019

 DOI: 10.1017/jpa.2018.95 

Abstract

The Flat Rocks locality in the Wonthaggi Formation (Strzelecki Group) of the Gippsland Basin, southeastern Australia, hosts fossils of a late Barremian vertebrate fauna that inhabited the ancient rift between Australia and Antarctica. Known from its dentary, Qantassaurus intrepidus Rich and Vickers-Rich, 1999 has been the only dinosaur named from this locality. However, the plethora of vertebrate fossils collected from Flat Rocks suggests that further dinosaurs await discovery. From this locality, we name a new small-bodied ornithopod, Galleonosaurus dorisae n. gen. n. sp. from craniodental remains. Five ornithopodan genera are now named from Victoria. Galleonosaurus dorisae n. gen. n. sp. is known from five maxillae, from which the first description of jaw growth in an Australian dinosaur is provided. The holotype of Galleonosaurus dorisae n. gen. n. sp. is the most complete dinosaur maxilla known from Victoria. Micro-CT imagery of the holotype reveals the complex internal anatomy of the neurovascular tract and antorbital fossa. We confirm that Q. intrepidus is uniquely characterized by a deep foreshortened dentary. Two dentaries originally referred to Q. intrepidus are reassigned to Q. ?intrepidus and a further maxilla is referred to cf. Atlascopcosaurus loadsi Rich and Rich, 1989. A further ornithopod dentary morphotype is identified, more elongate than those of Q. intrepidus and Q. ?intrepidus and with three more tooth positions. This dentary might pertain to Galleonosaurus dorisae n. gen. n. sp. Phylogenetic analysis recovered Cretaceous Victorian and Argentinian nonstyracosternan ornithopods within the exclusively Gondwanan clade Elasmaria. However, the large-bodied taxon Muttaburrasaurus langdoni Bartholomai and Molnar, 1981 is hypothesised as a basal iguanodontian with closer affinities to dryomorphans than to rhabdodontids.

Figure 4. Specimens of Galleonosaurus dorisae n. gen. n. sp. from the Flat Rocks Sandstone in the upper Barremian, Wonthaggi Formation, Gippsland Basin, southeastern Australia:
(1–2) holotype (NMV P229196), left maxilla in lateral (1) and medial (2) views; (3) NMV P208178, left maxilla in lateral view; (4) NMV P212845, left maxilla in lateral view; (5) NMV P209977, left maxilla in lateral view; (6) NMV P186440, left maxilla in lateral view; (7) NMV 208113, right maxillary tooth in labial view.

Scale bars = 10 mm (1–6); 1 mm (7).

 DOI: 10.1017/jpa.2018.95 

Systematic paleontology

Dinosauria Owen, 1842

Ornithischia Seeley, 1888

Neornithischia Cooper, 1985

Cerapoda Sereno, 1986

Ornithopoda Marsh, 1881

Genus Galleonosaurus new genus

Type species: Galleonosaurus dorisae n. gen. n. sp., by monotypy.

Etymology: From galleon (Latinization of the English for a type of large sailing ship) + saurus (New Latin from the Greek sauros for lizard), in reference to the appearance of the maxilla to the upturned hull of a galleon.

Occurrence: Flat Rocks locality in the Inverloch region of Victoria, southeastern Australia (Fig. 1); Flat Rocks Sandstone and The Caves Sandstone, upper Barremian of the Wonthaggi Formation in the Gippsland Basin.

Remarks: Prior to the recognition of Galleonosaurus n. gen., Atlascopcosaurus loadsi and Leaellynasaura amicagraphica were the only Victorian ornithopods identified from maxillary remains (Rich and Rich, 1989). The maxillae of Atlascopcosaurus loadsi are highly incomplete and the only known maxilla of L. amicagraphica (that of the holotype, NMV P185991) is damaged, and due to its diminutive size, difficult to study. The maxillae of Galleonosaurus n. gen., as well as the complete palatine and fragment of the lacrimal, now provide new information from which the anatomy of the other Victorian ornithopods can be better understood. The holotype of Galleonosaurus dorisae n. gen. n. sp. (NMV P229196) represents the most complete maxilla of a dinosaur currently known from Victoria.

Diagnosis: Small-bodied, noniguanodontian ornithopod characterized by five potential autapomorphies: (1) ascending ramus of maxilla has two slot-like foramina on the anterior margin that communicate with the neurovascular tract; (2) neurovascular tract bifurcates internally to exit at two anteroventral maxillary foramina; (3) lingual margin of maxillary tooth roots in midregion of tooth row form an S-bend at their bases; (4) posterior third of maxilla on some, but not all, specimens deflects posterolaterally at an abrupt kink; and (5) lateral end of palatine lateral ramus forms a hatchet-shaped flange.

Occurrence: Flat Rocks locality in the Inverloch region of Victoria, southeastern Australia (Fig. 1); Flat Rocks Sandstone and The Caves Sandstone, upper Barremian of the Wonthaggi Formation in the Gippsland Basin.

Etymology: dorisae, in recognition of Doris Seegets-Villiers for her geological, palynological, and taphonomic work on the Flat Rocks fossil vertebrate locality.

Figure 1. Maps of Australia, southern Victoria and Gondwana: (1) present-day eastern Australia indicating region of interest; (2) inset from (1) showing upper Barremian–lower Albian ornithopod localities and associated geology; (3) reconstruction of Gondwana during the late Barremian (~ 125 Ma) using GPlates (www.gplates.org). Dashed lines in (2) indicate basin boundaries. Geological information in (2) based on Bryan et al. (1997, 2000). V-shaped symbols in (3) indicate direction and position of plate subduction, based on Wandres and Bradshaw (2005). Australian paleoshoreline in (3) based on Heine et al. (2015). Dashed arrows in (2–3) indicate paleoflow direction. AAR = Australian-Antarctic rift; AF = Africa; AN = Antarctica; AU = Australia; I = India; EF = Eumeralla Formation; ES = epeiric Eromanga Sea (in region of Eromanga Basin); ETRW = Eric the Red West; M = Madagascar; NC = New Caledonia; NZ = New Zealand; SA = South America; VHFT2 = Victorian Hypsilophodontid Femur Type 2; VOPC1 = Victorian ornithopod postcranium 1 (NMV P185992/P185993); VOPC2 = Victorian ornithopod postcranium 2 (NMV P186047); W = Whitsunday Large Siliceous Igneous Province (Bryan et al., 1997); WF = Wonthaggi Formation.

Figure 27. Australian ornithopod occurrences: ETRW = Eric the Red West; VHFT2 = Victorian Hypsilophodontid Femur Type 2; VOD2 = Victorian ornithopod dentary morphotype 2; VOD3 = Victorian ornithopod dentary morphotype 3; VOM4 = Victorian ornithopod maxilla morphotype 4; VOPC1 = Victorian ornithopod postcranium 1 (NMV P185992/P185993); VOPC2 = Victorian ornithopod postcranium 2 (NMV P186047). See Table 5 for associated information on ornithopod occurrences.

Figure 28. Time-calibrated phylogeny of the ornithopods from the IW strict consensus cladogram (Fig. 25.2). Dashed lines indicate unknown times of Pangaean branch/lineage divergences prior to the middle Callovian. Time scale based on Cohen et al. (2013). Thick lines indicate taxon (graduated shaded lines) and clade (solid lines) durations (for sources, see Text S1). Aal = Aalenian; AF = Africa; Alb = Albian; AN = Antarctica; Apt = Aptian; AU = Australia; Baj = Bajocian; Bar = Barremian; Bat = Bathonian; Ber = Berriasian; Cal = Callovian; Cam = Campanian; Cen = Cenomanian; Con = Coniacian; Hau = Hauterivian; Kim = Kimmeridgian; LA = Laurasia; Maa = Maastrichtian; NZ = New Zealand; Oxf = Oxfordian; SA = South America; San = Santonian; Tit = Tithonian; Tur = Turonian; Val = Valanginian.

Conclusions: 

The identification of the new ornithopod, Galleonosaurus dorisae n. gen. n. sp., and three further jaw morphotypes (VOM4, VOD2, and VOD3) from the Flat Rocks locality in the upper Barremian Wonthaggi Formation complements the four previously named ornithopods from Victoria—Atlascopcosaurus loadsi, Diluvicursor pickeringi, Leaellynasaura amicagraphica, and Qantassaurus intrepidus. Although synonymy between some of these taxa is possible, Galleonosaurus dorisae n. gen. n. sp. and the newly identified craniodental morphotypes confirm that a highly diverse small-bodied ornithopod fauna flourished in the periodically disturbed, high-latitude, riverine floodplain environment of the Australian-Antarctic rift valley (see also Rich and Rich, 1989; Rich and Vickers-Rich, 1999, 2000; Rich et al., 2002; Herne et al., 2016, 2018).

The new dentary morphotype from the Flat Rocks Sandstone (VOD3) confirms the presence of an ornithopod with a more elongate dentary than that of Qantassaurus intrepidus, from the same locality, and with more alveoli in specimens of similar size (15 alveoli compared to 10). We speculate that VOD3 is a more likely candidate for the presently unknown dentary of Galleonosaurus dorisae n. gen. n. sp. than the dentary of Q. intrepidus, although this suggestion cannot be presently confirmed. The similarity between the dentary teeth of VOD3 and an isolated dentary tooth (QM F52774) discovered in the Winton Formation, central-western Queensland (Hocknull and Cook, 2008) suggests that the spatiotemporal range of potentially closely related ornithopods in eastern Australia extended from at least the upper Barremian of the Australian-Antarctic rift system to the lower Turonian of the Eromanga Basin (Figs. 1.3, 27).

The phylogenetic analysis (Figs. 25.2, 26) recovered the Victorian ornithopods Diluvicursor pickeringi, Leaellynasaura amicagraphica, and Galleonosaurus dorisae n. gen. n. sp. within Elasmaria (Calvo et al., 2007). In addition to the Victorian taxa, Elasmaria also comprises the Argentinian taxa Anabisetia saldiviai, Gasparinisaura cincosaltensis, Macrogryphosaurus gondwanicus, and Talenkauen santacrucensis. Increased anatomical understanding of the ornithopods recovered within Elasmaria, and particularly the Victorian ornithopods, will undoubtedly impel renewed phylogenetic assessment. The large-bodied Australian genus Muttaburrasaurus, however, is a nonelasmarian and was recovered within Iguanodontia. The time-calibrated phylogeny derived from the IW strict consensus tree (Fig. 28) suggests that Elasmaria and the stem of Muttaburrasaurus langdoni had their origins in Pangaea prior to the opening of seaways between Gondwana and Laurasia in the middle Callovian.

Matthew C. Herne, Jay P. Nair, Alistair R. Evans and Alan M. Tait. 2019. New Small-bodied Ornithopods (Dinosauria, Neornithischia) from the Early Cretaceous Wonthaggi Formation (Strzelecki Group) of the Australian-Antarctic Rift System, with Revision of Qantassaurus intrepidus Rich and Vickers-Rich, 1999. Journal of Paleontology. First View. DOI: 10.1017/jpa.2018.95

New wallaby-sized dinosaur from the ancient Australian-Antarctic rift valley https://phys.org/news/2019-03-wallaby-sized-dinosaur-ancient-australian-antarctic-rift.html via @physorg_com

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

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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.

[Paleontology • 2018] Diluvicursor pickeringi • A New Small-bodied Ornithopod (Dinosauria, Ornithischia) from A Deep, High-energy Early Cretaceous River of the Australian–Antarctic Rift System ---ScRaBBlE

Diluvicursor pickeringi

Herne​, Tait, Weisbecker, Hall, Nair, Cleeland & Salisbury, 2018

Artwork by P. Trusler.  DOI: 10.7717/peerj.4113 

Abstract

A new small-bodied ornithopod dinosaur, Diluvicursor pickeringi, gen. et sp. nov., is named from the lower Albian of the Eumeralla Formation in southeastern Australia and helps shed new light on the anatomy and diversity of Gondwanan ornithopods. Comprising an almost complete tail and partial lower right hindlimb, the holotype (NMV P221080) was deposited as a carcass or body-part in a log-filled scour near the base of a deep, high-energy river that incised a faunally rich, substantially forested riverine floodplain within the Australian–Antarctic rift graben. The deposit is termed the ‘Eric the Red West Sandstone.’ The holotype, interpreted as an older juvenile ∼1.2 m in total length, appears to have endured antemortem trauma to the pes. A referred, isolated posterior caudal vertebra (NMV P229456) from the holotype locality, suggests D. pickeringi grew to at least 2.3 m in length. D. pickeringi is characterised by 10 potential autapomorphies, among which dorsoventrally low neural arches and transversely broad caudal ribs on the anterior-most caudal vertebrae are a visually defining combination of features. These features suggest D. pickeringi had robust anterior caudal musculature and strong locomotor abilities. Another isolated anterior caudal vertebra (NMV P228342) from the same deposit, suggests that the fossil assemblage hosts at least two ornithopod taxa. D. pickeringi and two stratigraphically younger, indeterminate Eumeralla Formation ornithopods from Dinosaur Cove, NMV P185992/P185993 and NMV P186047, are closely related. However, the tail of D. pickeringi is far shorter than that of NMV P185992/P185993 and its pes more robust than that of NMV P186047. Preliminary cladistic analysis, utilising three existing datasets, failed to resolve D. pickeringi beyond a large polytomy of Ornithopoda. However, qualitative assessment of shared anatomical features suggest that the Eumeralla Formation ornithopods, South American Anabisetia saldiviai and Gasparinisaura cincosaltensis, Afro-Laurasian dryosaurids and possibly Antarctic Morrosaurus antarcticus share a close phylogenetic progenitor. Future phylogenetic analysis with improved data on Australian ornithopods will help to test these suggested affinities.

Systematic Palaeontology

ORNITHISCHIA Seeley, 1888

CERAPODA Sereno, 1986

ORNITHOPODA Marsh, 1881

Figure 6: Partial postcranium, NMV P221080, assigned to the holotype of Diluvicursor pickeringi gen. et sp. nov., as prepared on five blocks of ETRW Sandstone. (A) Specimen viewed from above, normal to the bedding. (B) Schematic.

Abbreviations: as, astragalus; B #, host block number; Ca #, designated caudal vertebra and position; cal, calcaneum; fib, fibula; ha #, haemal arch/process and position; pd #, pedal digit number; tib, tibia. Image of NMV P221080, courtesy S. Poropat and Museums Victoria.

Figure 7: Diluvicursor pickeringi gen. et sp. nov. holotype (NMV P221080), schematic restoration in left lateral view, showing preserved bones (light shading) and incomplete caudal vertebrae (outlined). 

Abbreviations: as, astragalus; Ca #, designated caudal vertebral position; pd #, pedal digit number; tib, tibia.

Diluvicursor gen. nov.  

Etymology: From the Latin ‘diluvi,’ for deluge or flood, in reference to the deep high-energy palaeo-river within which the type material was deposited and the palaeo-floodplain upon which the river extended, combined with the suffix ‘-cursor,’ from the Latin for runner.

Diagnosis: A turkey- to rhea-sized small-bodied ornithopod, differentiated from all other ornithopods by 10 potential autapomorphies: (1) dorsoventral height of the neural arch on the anterior-most caudal vertebrae (indicated at Ca 3), highly reduced and sub-equal to dorsoventral centrum height; (2) proximodistal length of the spinal process on the anterior caudal vertebrae (Ca 3–6), highly reduced and sub-equal to anteroposterior centrum length; (3) prezygapophysis on the anterior-most caudal vertebrae (up to Ca 5), horizontally oriented and located at the neural arch base, lateral to the neural canal; (4) tuberous process dorsally on the spinoprezygapophyseal lamina (sprl) of the anterior-most caudal vertebrae; (5) dorsoventrally narrowest part of the centrum on the posterior caudal vertebrae, distinctly offset posteriorly and embayed by a sulcus; (6) deep haemal groove present on all posterior caudal vertebrae; (7) triangular intervertebral process anteriorly on the centrum of the posterior-most caudal vertebrae incises a V-shaped notch at the posterior end of the adjoining centrum; (8) caudal ribs on the anterior-most caudal vertebrae (indicated at Ca 3) are transversely broad with the distance across the ribs ∼85% of total vertebral height (inclusive of haemal arch); (9) lateral distal tarsal embayed anteriorly by a sulcus for the calcaneum; and (10) pd IV-1 is strongly asymmetrical in dorsoplantar view (the proximal cotyle flares medially and the lateral edge is straight).

Diluvicursor pickeringi sp. nov.   

2009 Ornithopoda; Rich et al., p. 677.

2014 Ornithopoda; Herne, pp. 246–274.

Derivation of name: To acknowledge the significant contribution of David A. Pickering to Australian palaeontology and in memory of his passing during the production of this work.

Distribution: Lower Cretaceous Australia.

Locality: Eric the Red West, ETRW Sandstone, lower Albian, Eumeralla Formation, Otway Group, southern Victoria.

Figure 36: Artist’s interpretation of the early Albian, volcaniclastic, floodplain palaeoenvironment within the Australian-Antarctic rift graben, in the region of Eric the Red West.
Scene depicting two individuals of Diluvicursor pickeringi on the cutbank of a high-energy meandering river, regional floral components and distant rift margin uplands. Floral components potentially included forest trees of Araucariaceae (Agathis and Araucaria), Podocarpaceae and Cupressaceae and lower story/ground cover plants, including pteridophytes (ferns, including equisetaleans), hepatics, lycopods, cycadophytes, bennettitaleans, seed-bearing fern- or cycad-like taeniopterids and early Australian angiosperms.

 Artwork by P. Trusler.

Conclusion

Diluvicursor pickeringi nov. gen. et sp. is a new small-bodied ornithopod from the lower Albian of the Eumeralla Formation in the Otway Basin. The taxon is known from an almost complete tail and lower partial right limb of the holotype (NMV P221080), as well as an isolated posterior caudal vertebra (NMV P229456), discovered at the fossil locality of Eric the Red West (ETRW). The deposit, termed the ETRW Sandstone, is interpreted to have been a broad (∼600 m), deep (∼25 m), high-energy meandering river. Sediments and fossils from the ETRW Sandstone indicate that D. pickeringi inhabited a faunally rich, substantially forested riverine floodplain within the Australian–Antarctic rift complex. A further isolated caudal vertebra from the deposit (NMV P228342), interpreted as that of an indeterminate ornithischian, suggests the locality may have hosted at least two small-bodied ornithischians. D. pickeringi grew to at least 2.3 m in length and is characterised by 10 potential autapomorphies, among which, the combination of dorsoventrally low neural arches and transversely broad caudal ribs on the anterior-most caudal vertebrae present a visually defining combination of features.

Features of the caudal vertebrae and pes suggest that D. pickeringi and the two stratigraphically younger, indeterminate ornithopods from Dinosaur Cove, NMV P185992/P185993 and NMV P186047, are closely related. However, D. pickeringi differs from NMV P185992/P185993 by having a far shorter tail (50 vertebrae compared to >71) and from NMV P186047 by having a comparatively shorter, more robust, pes. The phylogenetic position of D. pickeringi investigated through searches within three recently published datasets was unresolved beyond placement within a polytomous clade of non-iguanodontian ornithopods. Various features of the caudal vertebrae and pes suggest that the Eumeralla Formation ornithopods Diluvicursor, NMV P185992/P185993 and NMV P186047 may be more closely related to the Argentinean ornithopods Anabisetia and Gasparinisaura, the Antarctic ornithopod Morrosaurus and possibly Afro-Laurasian dryosaurids, than all other ornithopods. A common progenitor of these taxa is suggested. However, these suggested affinities are to be tested more rigorously within a revised cladistic dataset of Gondwanan ornithopods.

The discovery of D. pickeringi in the ETRW Sandstone indicates that future prospecting efforts in the Eumeralla Formation at locations where coarse, gritty sediments crop-out at the base of deep palaeoriver channels, could lead to significant new discoveries (see also Rich et al., 2009b). The articulated postcrania of similarly sized, but anatomically differing small-bodied ornithopods from the Eumeralla Formation provide unique fossil material for future comparative investigations on dinosaur biomechanics, and how differing locomotor abilities could relate to differing palaeoecosystems.

Matthew C. Herne​, Alan M. Tait, Vera Weisbecker, Michael Hall, Jay P. Nair, Michael Cleeland and Steven W. Salisbury. 2018. A New Small-bodied Ornithopod (Dinosauria, Ornithischia) from A Deep, High-energy Early Cretaceous River of the Australian–Antarctic Rift System.  PeerJ. 5:e4113.  DOI: 10.7717/peerj.4113

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روابط التحميل والمشاهدة، الروابط المباشرة للتحميل

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شاهد هذا الفيديو القصير لطريقة التحميل البسيطة

منتدى مدونات بلوجر جاهزة بآلاف المواضيع والمشاركات

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.