A reevaluation of Sigilmassasaurus brevicollis (Dinosauria) from the Cretaceous of Morocco

2013 ◽  
Vol 50 (6) ◽  
pp. 636-649 ◽  
Author(s):  
Bradley McFeeters ◽  
Michael J. Ryan ◽  
Sanja Hinic-Frlog ◽  
Claudia Schröder-Adams
Keyword(s):  
Phylogenetic Analysis ◽  
Diagnostic Character ◽  
Neural Spine ◽  
Dorsal Margin ◽  
Neural Arch ◽  
Anterior Dorsal ◽  
Neural Canal ◽  
Valid Taxon

The original hypodigm of the controversial mid-Cretaceous Moroccan dinosaur Sigilmassasaurus brevicollis is redescribed, and the diagnosis of the taxon is revised. Unambiguously referred material is restricted to cervical and anterior dorsal vertebrae sharing apomorphies with the holotype. A newly recognized diagnostic character of Sigilmassasaurus is the absence of anterior and posterior interzygapophyseal laminae of the neural arch, so that the neural spine directly meets the dorsal margin of the neural canal. A phylogenetic analysis supports the inclusion of Sigilmassasaurus in Tetanurae but not in Carcharodontosauridae. Sigilmassasaurus is distinct from all other theropods known from comparable material and is thus retained as a valid taxon.

scholarly journals First rebbachisaurid sauropod dinosaur from Asia

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246620
Author(s):  
Alexander Averianov ◽  
Hans-Dieter Sues
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Upper Cretaceous ◽  
Neural Spine ◽  
Lateral Side ◽  
New Taxon ◽  
Caudal Vertebra

Dzharatitanis kingi gen. et sp. nov. is based on an isolated anterior caudal vertebra (USNM 538127) from the Upper Cretaceous (Turonian) Bissekty Formation at Dzharakuduk, Uzbekistan. Phylogenetic analysis places the new taxon within the diplodocoid clade Rebbachisauridae. This is the first rebbachisaurid reported from Asia and one of the youngest rebbachisaurids in the known fossil record. The caudal is characterized by a slightly opisthocoelous centrum, ‘wing-like’ transverse processes with large but shallow PRCDF and POCDF, and the absence of a hyposphenal ridge and of TPRL and TPOL. The neural spine has high SPRL, SPDL, SPOL, and POSL and is pneumatized. The apex of neural spine is transversely expanded and bears triangular lateral processes. The new taxon shares with Demandasaurus and the Wessex rebbachisaurid a high SPDL on the lateral side of the neural spine, separated from SPRL and SPOL. This possibly suggests derivation of Dzharatitanis from European rebbachisaurids. This is the second sauropod group identified in the assemblage of non-avian dinosaurs from the Bissekty Formation, in addition to a previously identified indeterminate titanosaurian.

Morphology of the atlas-axis complex of the late Palaeozoic tetrapod suborders Diadectomorpha and Seymouriamorpha

1992 ◽  
Vol 336 (1277) ◽  
pp. 259-273 ◽  
Keyword(s):  
Posterior Margin ◽  
Dorsal Surface ◽  
Neural Spine ◽  
Neural Arch ◽  
Total Height ◽  
Late Palaeozoic

The atlas-axis complexes of the better-known genera of the Permo-Pennsylvanian tetrapod suborder Diadectomorpha are described and compared with those of other late Palaeozoic tetrapods. One new synapomorphy of the Diadectomorpha is identified: a large, anteriorly directed, midventral, projection of the axial intercentrum that articulates with a midventral furrow on the posterior margin of the atlantalintercentrum . Within the Diadectomorpha diadectids are apomorphic in possessing a large, anteriorly tapering axial neural spine, that accounts for approximately 40% of the total height of the axis; Limnoscelis is apomorphic in having divided parapophyseal facets of the atlantal intercentrum and anteriorly directed ventral processes of the atlantal intercentrum . Relative to the atlas-axis complex in the more primitive amphibian suborder Seymouriamorpha, that of diadectomorphs and other basal amniotes share two derived features: the atlantal pleurocentrum is fused to the dorsal surface of the axial intercentrum , except in Tseajaia where the elements are not fused but are positioned similarly; and the axial pleurocentrum and neural arch are fused in all observable stages of ontogeny. Reinterpretation of the atlantal neural arch in Seymouria indicates that it does not possess neural spines, a feature it shares with the Diadectomorpha and basal amniotes.

scholarly journals Morphology-based phylogenetic analysis of the treehopper tribe Smiliini (Hemiptera: Membracidae: Smiliinae), with reinstatement of the tribe Telamonini

Zootaxa ◽  
2011 ◽  
Vol 3047 (1) ◽  
pp. 1 ◽  
Author(s):  
MATTHEW S. WALLACE
Keyword(s):  
Phylogenetic Analysis ◽  
Common Ancestor ◽  
Hind Wing ◽  
Morphological Characters ◽  
Dorsal Margin ◽  
Incertae Sedis ◽  
Plant Associations ◽  
Original Dataset ◽  
The Common ◽  
Morphological Differences

Members of the Smiliini, the nominotypical tribe of the large New World subfamily Smiliinae, are predominately Nearctic in distribution. This tribe included 169 mostly tree-feeding species in 23 genera. A parsimony-based phylogenetic analysis of an original dataset comprising 89 traditional and newly discovered morphological characters for 69 species, including representatives of 22 of the 23 described genera of Smiliini and five other previously recognized tribes of the subfamily, resulted in a single most parsimonious tree with three major clades. The broad recent concept of Smiliini (including Telamonini as a junior synonym) was not recovered as monophyletic by the analysis. Instead, the analysis supported narrower definitions of both Telamonini, here reinstated from synonymy, and Smiliini. A key and diagnoses are given to define these tribes, along with discussions of their phylogeny, biogeography, and host plant associations. The genera Antianthe Fowler, Hemicardiacus Plummer, Smilirhexia McKamey, and Tropidarnis Fowler are placed as Smiliinae, incertae sedis. Based on the phylogeny, several genera from both tribes including Atymna Stål, Cyrtolobus Goding, Heliria Stål, and Telamona Fitch are not monophyletic. Diagnostic characters emphasizing the morphological differences between the Smiliini and Telamonini include the dorsal margin of the head, the shape of the pronotum, the size of the pronotal humeral angles, the presence or absence of pronotal longitudinal rugae, the size of forewing cells, variations in the fusion of veins R and M apically in both the foreand hind wing, and the shape of the apex of the female second valvulae. Mapping geographic distribution onto the phylogeny suggests that the common ancestor of the ingroup (all three clades) occurred in Central America and Mexico, with multiple dispersals to temperate North America. Many Smiliini and Telamonini feed on various species of oak (Quercus) and the close evolutionary association between these insects and their hosts is discussed.

Aphaneramma kokeni (von Huene, 1920), a lonchorhynchine trematosaurid (Amphibia: Temnospondyli) from the Lower Triassic of Pakistan

2020 ◽  
Vol 295 (3) ◽  
pp. 211-241
Author(s):  
Michael W. Maisch
Keyword(s):  
Phylogenetic Analysis ◽  
Lower Triassic ◽  
The Other ◽  
External Exposure ◽  
Nominal Species ◽  
Islamic Republic ◽  
Valid Taxon ◽  
New Diagnosis ◽  
Skull Bones

The type and only known specimen of the lonchorhynchine trematosaurid Aphaneramma kokeni (von Huene, 1920) from the Mianwali Formation (Lower Triassic, Dienerian) of Chiddru, Punjab, Islamic Republic of Pakistan, is redescribed. It is demonstrated that A. kokeni is a valid taxon clearly distinct from other nominal species of the genus and a new diagnosis is provided. The preorbital region of A. kokeni differs considerably from other Aphaneramma species by the small external exposure of the lacrimal, which is almost completely overlapped by the prefrontal, as in some other trematosaurs such as Cosgriffius, Wantzosaurus and Trematolestes. It also differs in the arrangement of the postorbital dermal skull bones, particularly the short postfrontal, lack (or almost so) of a postfrontal-supratemporal contact and the posteriorly extensive frontals, as well as a unique dentition on the ectopterygoid. Phylogenetic analysis places the species in a monophyletic genus Aphaneramma, in a polytomy with the other two nominal species of the genus.

Earliest North American articulated freshwater acanthomorph fish (Teleostei: Percopsiformes) from Upper Cretaceous deposits of Alberta, Canada

2019 ◽  
Vol 157 (7) ◽  
pp. 1087-1096
Author(s):  
Alison M. Murray ◽  
Donald B. Brinkman ◽  
Michael G. Newbrey ◽  
Andrew G. Neuman
Keyword(s):  
Phylogenetic Analysis ◽  
Upper Cretaceous ◽  
New Genus ◽  
Sister Group ◽  
Neural Spine ◽  
New Taxon ◽  
New Genus And Species ◽  
Fossil Material ◽  
Species Being ◽  
Cretaceous Deposits

AbstractFossil material from the Maastrichtian part of the Scollard Formation is identified as belonging to an acanthomorph fish. An articulated specimen, preserved in part and counterpart, is a member of the paracanthopterygian order Percopsiformes, based on it having a full neural spine on the second preural centrum and two epurals in the caudal skeleton (both paracanthopterygian characters), as well as six branchiostegal rays and an anterodorsal excavated margin on the opercle (percopsiform characters). We name this as a new genus and species, Lindoeichthys albertensis. A phylogenetic analysis with no prior constraints recovered a single most-parsimonious tree with the new taxon placed as the sister group to a clade containing the Palaeocene Montana genus Mcconichthys + Percopsidae. However, this analysis did not recover the traditional percopsiforms (including Aphredoderidae and Amblyopsidae) as monophyletic. A second analysis, in which we constrained the traditional members of the Percopsiformes to be monophyletic, resulted in the new species being placed as the sister group to Percopsis. The articulated percopsiform specimen from the Pisces Point locality allows isolated dentaries from vertebrate microfossil localities to be identified as being from a member of that group. These isolated elements first appear in the late Campanian Judith River Group of Alberta and the Kaiparowits Formation of Utah, documenting that percopsiform fishes were present in the Western Interior of North America at least 75 Ma ago.

The atlas-axis complex in the late Paleozoic genus Diadectes and the characteristics of the atlas-axis complex across the amphibian to amniote transition

1991 ◽  
Vol 65 (6) ◽  
pp. 973-983 ◽  
Author(s):  
Stuart S. Sumida ◽  
R. Eric Lombard
Keyword(s):  
Late Paleozoic ◽  
Neural Spine ◽  
Early Permian ◽  
Neural Arch ◽  
Exposure Fusion

The atlas-axis complex in the Early Permian diadectomorph Diadectes is shown to be similar to those of a variety of primitive amniotes. Diadectes does not possess elements in addition to the standard complement seen in advanced batrachosaurs and primitive amniotes as previously thought. Characteristics of the complex include: paired, well-developed proatlases and atlantal neural arches, lack of atlantal neural spines, an extremely robust atlantal intercentrum, fusion of the atlantal pleurocentrum and axial intercentrum, a large anterior projection of the axial intercentrum, exclusion of the atlantal pleurocentrum from ventral exposure, fusion of axial neural arch and pleurocentrum, and a robustly developed axial neural spine. An analysis of the transformations of the atlas-axis complex in advanced anthracosaurs and primitive amniotes indicates that many of the characteristics of the complex previously thought to be definitive of amniotes or reptiles appear to be conditions common to Diadectes plus Amniota.

scholarly journals Additional sauropod dinosaur material from the Callovian Oxford Clay Formation, Peterborough, UK: evidence for higher sauropod diversity

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6404
Author(s):  
Femke M. Holwerda ◽  
Mark Evans ◽  
Jeff J. Liston
Keyword(s):  
Transverse Process ◽  
Neural Spine ◽  
Caudal Vertebra ◽  
High Complexity ◽  
Neural Arch ◽  
Faunal Assemblage ◽  
Diagnostic Features ◽  
Nutrient Foramina ◽  
Tentative Evidence ◽  
Clay Formation

Four isolated sauropod axial elements from the Oxford Clay Formation (Callovian, Middle Jurassic) of Peterborough, UK, are described. Two associated posterior dorsal vertebrae show a dorsoventrally elongated centrum and short neural arch, and nutrient or pneumatic foramina, most likely belonging to a non-neosauropod eusauropod, but showing ambiguous non-neosauropod eusauropod and neosauropod affinities. An isolated anterior caudal vertebra displays a ventral keel, a ‘shoulder’ indicating a wing-like transverse process, along with a possible prespinal lamina. This, together with an overall high complexity of the anterior caudal transverse process (ACTP) complex, indicates that this caudal could have belonged to a neosauropod. A second isolated middle-posterior caudal vertebra also shows some diagnostic features, despite the neural spine and neural arch not being preserved and the neurocentral sutures being unfused. The positioning of the neurocentral sutures on the anterior one third of the centrum indicates a middle caudal position, and the presence of faint ventrolateral crests, as well as a rhomboid anterior articulation surface, suggest neosauropod affinities. The presence of possible nutrient foramina are only tentative evidence of a neosauropod origin, as they are also found in Late Jurassic non-neosauropod eusauropods. As the caudals from the two other known sauropods from the Peterborough Oxford Clay, Cetiosauriscus stewarti and an indeterminate non-neosauropod eusauropod, do not show the features seen on either of the new elements described, both isolated caudals indicate a higher sauropod species diversity in the faunal assemblage than previously recognised. An exploratory phylogenetic analysis using characters from all four isolated elements supports a basal neosauropod placement for the anterior caudal, and a diplodocid origin for the middle caudal. The dorsal vertebrae are an unstable OTU, and therefore remain part of an indeterminate eusauropod of uncertain affinities. Together with Cetiosauriscus, and other material assigned to different sauropod groups, this study indicates the presence of a higher sauropod biodiversity in the Oxford Clay Formation than previously recognised. This study shows that it is still beneficial to examine isolated elements, as these may be indicators for higher species richness in deposits that are otherwise poor in terrestrial fauna.

scholarly journals The anatomy and relationships of Eucamerotus foxi (Dinosauria, Sauropoda) from the Early Cretaceous of England

2017 ◽  
Author(s):  
Amy Campbell ◽  
Paul Upchurch ◽  
Phillip D Mannion
Keyword(s):  
Phylogenetic Analysis ◽  
Early Cretaceous ◽  
Valid Species ◽  
Neural Arch ◽  
Isle Of Wight

Eucamerotus foxi is a macronarian sauropod from the Wessex Formation (Early Cretaceous, Barremian) of the Isle of Wight. It is represented by NHMUK R2522, a partial dorsal neural arch, and differs from other known sauropods by the presence of a stout robust prezygoparapophyseal lamina (PRPL) which bifurcates distally. NHMUK R90 are a pair of dorsal vertebrae also from the Wessex Formation which have been designated as paratypes of E. foxi. Both NHMUK R2522 and NHMUK R90 have traditionally been regarded as either basal titanosauriformes or of brachiosaurid affinities. Here, phylogenetic analysis using the Lusotitan Standard Discrete Matrix recovered NHMUK R90 as a non-titanosaurian somphospondylan nested in a clade made up of ((Tastavinsaurus (Chubutisaurus, Angolatitan, NHMUK R90)) though Bremer support for this group was low. Analyses recovered E. foxi as a neosauropod of uncertain affinities with little resolution throughout the tree. NHMUK R90 is recognised as being distinct from E. foxi based on the lack of a robust distally bifurcated PRPL and is likely representative of a new sauropod taxon. E. foxi is here retained as a valid species of basal macronarian.

scholarly journals What do we mean by the directions “cranial” and “caudal” on a vertebra?

2019 ◽  
Author(s):  
Michael P Taylor ◽  
Matthew J Wedel
Keyword(s):  
Spinal Column ◽  
Lateral View ◽  
Horizontal Axis ◽  
Neural Arch ◽  
Objective Measurements ◽  
Articular Surfaces ◽  
Neural Canal ◽  
Arch Neural

In illustrating vertebrae, it is important to consistently depict their orientation, so we can objectively assess and compare the slope of the neural arch, neural canal, or articular surfaces. However, differing vertebral shapes across taxa and across regions of the spinal column make it difficult to maintain consistency, or even define what we mean by the directions “cranial” and “caudal”. Consequently, characters such as “Neural arch slopes cranially 30° relative to the vertical” are disputable rather than objective measurements. Cranial and caudal are defined as directed along the horizontal axis, but several different notions of “horizontal” are possible: 1. Long axis of centrum is horizontal. This is appealing for elongate vertebrae such as sauropod cervicals, but is not always well defined, and is difficult to determine for craniocaudally short vertebrae such as most caudals. 2. Articular surfaces of centrum are vertical. Difficult to determine when dealing with facets that are concave or (worse) convex; and ambiguous for “keystoned” vertebrae in which the facets are not parallel. 3. Neural canal is horizontal. Anatomically informative, but difficult to determine in vertebrae that have not been fully prepared or CT-scanned, and impossible to see in lateral view. Ambiguous for vertebrae where the dorsal and ventral margins of the canal are not straight or not parallel. 4. Similarity in articulation (“horizontal” is defined as a line joining the same point on two similarly oriented copies of the same vertebra when optimally articulated). This is less intuitive than definitions 1–3, but takes the entire vertebra into account. We advocate explicitly stating a definition and using it consistently. In most cases, definition 3 (“Neural canal is horizontal”) best reflects anatomical and developmental realities, and it is therefore preferred. Low-tech techniques can be used to determine neural canal orientation with adequate precision for most purposes.

Redescription of the archosaur Parringtonia gracilis from the Middle Triassic Manda beds of Tanzania, and the antiquity of Erpetosuchidae

2012 ◽  
Vol 150 (2) ◽  
pp. 225-238 ◽  
Author(s):  
STERLING J. NESBITT ◽  
RICHARD J. BUTLER
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Middle Triassic ◽  
Upper Triassic ◽  
Late Triassic ◽  
Dorsal Margin ◽  
Posterior Portion ◽  
Anterior Half

AbstractParringtonia gracilis Huene, 1939 is represented by both cranial and postcranial material collected from the lower Middle Triassic (Anisian) Lifua Member of the Manda beds in southwestern Tanzania. This aberrant taxon was previously proposed to have affinities with pseudosuchian archosaurs, and specifically with the enigmatic Erpetosuchus granti from the Upper Triassic of Scotland. Here, we confirm the close affinities of Parringtonia gracilis and Erpetosuchus granti based on the following unambiguous synapomorphies: mediolaterally expanded posterior portion of the maxilla, alveoli present only in the anterior half of the maxilla, and absence of tooth serrations. Furthermore, the two taxa share osteoderms with deep sculpturing, a deep fossa on the dorsal margin of the neural spines and a heavily waisted shaft of the scapula. We added both Parringtonia gracilis and Erpetosuchus granti into a comprehensive phylogenetic analysis of early archosaurs and found that these taxa are clearly referable to Archosauria but that relationships are poorly resolved at the base of this clade. However, our analysis demonstrates that Erpetosuchus granti is not closely related to Crocodylomorpha, as has been hypothesized previously. The Erpetosuchidae are a clade of small-bodied archosaurs that have a poor fossil record but have members from both northern and southern Pangaea, ranging temporally from the Middle to Late Triassic. Thus, Erpetosuchidae is part of the early archosaurian radiation.

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