The nasal cavity of two traversodontid cynodonts (Eucynodontia, Gomphodontia) from the Upper Triassic of Brazil

2021 ◽  
pp. 1-16
Author(s):  
Arymathéia Santos Franco ◽  
Rodrigo Temp Müller ◽  
Agustín G. Martinelli ◽  
Carolina A. Hoffmann ◽  
Leonardo Kerber

Abstract Traversodontidae is a group of Triassic herbivorous/omnivorous cynodonts that represents the most diversified lineage within Cynognathia. In southern Brazil, a rich fossil record of late Middle/mid-Late Triassic cynodonts has been documented, with Exaeretodon riograndensis Abdala, Barberena, and Dornelles, 2002 and Siriusgnathus niemeyerorum Pavanatto et al., 2018 representing two abundant and well-documented traversodontids. The present study provides a comparative analysis of the morphology of the nasal cavity, nasal recesses, nasolacrimal duct, and maxillary canals of both species using computed tomography, highlighting the changes that occurred in parallel to the origin of mammaliaforms. Our results show that there were no ossified turbinals or a cribriform plate delimiting the posterior end of the nasal cavity, suggesting these structures were probably cartilaginous as in nonmammaliaform cynodonts. Both species show lateral ridges on the internal surface of the roof of the nasal cavity, but the median ridge for the attachment of a nasal septum is absent. Exaeretodon riograndensis and S. niemeyerorum show recesses on the dorsal region of the nasal cavity, which increase the volume of the nasal cavity, potentially enhancing the olfactory chamber and contributing to the sense of smell. On the lateral sides of the nasal cavity, the analyzed taxa show a well-developed maxillary recess. Although E. riograndensis and S. niemeyerorum have roughly similar nasal cavities, in the former taxon, the space between the left and right dorsal recesses of the nasal cavity is uniform along its entire extension, whereas this space narrows posteriorly in S. niemeyerorum. Finally, the nasolacrimal duct of S. niemeyerorum is more inclined anteroposteriorly than in E. riograndensis.

2007 ◽  
Vol 274 (1620) ◽  
pp. 1885-1893 ◽  
Author(s):  
Torsten M Scheyer ◽  
P.Martin Sander

The palaeoecology of basal turtles from the Late Triassic was classically viewed as being semi-aquatic, similar to the lifestyle of modern snapping turtles. Lately, this view was questioned based on limb bone proportions, and a terrestrial palaeoecology was suggested for the turtle stem. Here, we present independent shell bone microstructural evidence for a terrestrial habitat of the oldest and basal most well-known turtles, i.e. the Upper Triassic Proterochersis robusta and Proganochelys quenstedti . Comparison of their shell bone histology with that of extant turtles preferring either aquatic habitats or terrestrial habitats clearly reveals congruence with terrestrial turtle taxa. Similarities in the shell bones of these turtles are a diploe structure with well-developed external and internal cortices, weak vascularization of the compact bone layers and a dense nature of the interior cancellous bone with overall short trabeculae. On the other hand, ‘aquatic’ turtles tend to reduce cortical bone layers, while increasing overall vascularization of the bone tissue. In contrast to the study of limb bone proportions, the present study is independent from the uncommon preservation of appendicular skeletal elements in fossil turtles, enabling the palaeoecological study of a much broader range of incompletely known turtle taxa in the fossil record.


2008 ◽  
Vol 276 (1656) ◽  
pp. 507-513 ◽  
Author(s):  
Walter G Joyce ◽  
Spencer G Lucas ◽  
Torsten M Scheyer ◽  
Andrew B Heckert ◽  
Adrian P Hunt

A new, thin-shelled fossil from the Upper Triassic (Revueltian: Norian) Chinle Group of New Mexico, Chinlechelys tenertesta , is one of the most primitive known unambiguous members of the turtle stem lineage. The thin-shelled nature of the new turtle combined with its likely terrestrial habitat preference hint at taphonomic filters that basal turtles had to overcome before entering the fossil record. Chinlechelys tenertesta possesses neck spines formed by multiple osteoderms, indicating that the earliest known turtles were covered with rows of dermal armour. More importantly, the primitive, vertically oriented dorsal ribs of the new turtle are only poorly associated with the overlying costal bones, indicating that these two structures are independent ossifications in basal turtles. These novel observations lend support to the hypothesis that the turtle shell was originally a complex composite in which dermal armour fused with the endoskeletal ribs and vertebrae of an ancestral lineage instead of forming de novo. The critical shell elements (i.e. costals and neurals) are thus not simple outgrowths of the bone of the endoskeletal elements as has been hypothesized from some embryological observations.


2013 ◽  
Vol 280 (1772) ◽  
pp. 20132057 ◽  
Author(s):  
Ricardo N. Martínez ◽  
Cecilia Apaldetti ◽  
Carina E. Colombi ◽  
Angel Praderio ◽  
Eliana Fernandez ◽  
...  

Sphenodontians were a successful group of rhynchocephalian reptiles that dominated the fossil record of Lepidosauria during the Triassic and Jurassic. Although evidence of extinction is seen at the end of the Laurasian Early Cretaceous, they appeared to remain numerically abundant in South America until the end of the period. Most of the known Late Cretaceous record in South America is composed of opisthodontians, the herbivorous branch of Sphenodontia, whose oldest members were until recently reported to be from the Kimmeridgian–Tithonian (Late Jurassic). Here, we report a new sphenodontian, Sphenotitan leyesi gen. et sp. nov., collected from the Upper Triassic Quebrada del Barro Formation of northwestern Argentina. Phylogenetic analysis identifies Sphenotitan as a basal member of Opisthodontia, extending the known record of opisthodontians and the origin of herbivory in this group by 50 Myr.


2012 ◽  
Vol 150 (2) ◽  
pp. 225-238 ◽  
Author(s):  
STERLING J. NESBITT ◽  
RICHARD J. BUTLER

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.


Zootaxa ◽  
2019 ◽  
Vol 4629 (1) ◽  
pp. 146-150 ◽  
Author(s):  
MAURÍCIO S. GARCIA ◽  
RODRIGO T. MÜLLER ◽  
SÉRGIO DIAS-DA-SILVA

The controversial dinosauriform Teyuwasu barberenai Kischlat, 1999 (Fig. 1B) is based on a right femur (BSPG AS XXV 53) and tibia (BSPG AS XXV 54), formerly referred to the pseudosuchian ‘Hoplitosuchus raui’ (= Hoplitosaurus raui) Huene, 1938 (see also Huene, 1942). This material comes from a classic Late Triassic (Carnian) locality in southern Brazil (Fig. 1A), the Cerro da Alemoa outcrop on the Alemoa complex, that has yielded several noteworthy tetrapod specimens (see Garcia et al., 2019, for a complete list of references). When reviewing these abovementioned materials, Kischlat (1999) considered it to belong to a “robust saurischian dinosaur”, but later this taxon was considered to be a nomen dubium (Langer et al., 2010; Ezcurra, 2012). Foremost, the initial description of this taxon is problematic, because Kischlat (1999) presented it in a symposium abstract which does not constitute a published work [which is not allowed under the Art. 9.10 of the International Commission on Zoological Nomenclature (ICZN)]. Moreover, the author did not list traits that clearly differentiated Teyuwasu from other coeval dinosauriforms (cf. Art. 13 of the ICZN, see further below). In particular, it was not adequately distinguished from Staurikosaurus pricei Colbert, 1970 (Fig. 1B), which also comes from the same Alemoa complex, but from another nearby outcrop (Sanga Grande/Sanga de Baixo) considered equivalent in stratigraphic level and horizon with the lower levels of the Cerro da Alemoa site (Huene, 1942; Colbert, 1970; see also Garcia et al., 2019) (Fig. 1A). However, Huene (1942) did not clearly specify that the materials (femur and tibia) later assembled by Kischlat (1999) into the holotype of Teyuwasu were found in close association, although Huene (1942) cited that they come from the same stratigraphical level and horizon, and to our interpretation, their morphology and preservational features are compatible. Still, assigning these bones as part of a single individual is tentative. 


Zootaxa ◽  
2018 ◽  
Vol 4457 (3) ◽  
pp. 351 ◽  
Author(s):  
MICHELI STEFANELLO ◽  
RODRIGO TEMP MÜLLER ◽  
LEONARDO KERBER ◽  
RICARDO N. MARTÍNEZ ◽  
SÉRGIO DIAS-DA-SILVA

Ecteniniidae comprises an endemic radiation of carnivore probainognathian cynodonts from the Late Triassic of South America. Three taxa have been included in this clade: Ecteninion lunensis Martínez et al., 1996 and Diegocanis elegans Martínez et al., 2013 from Argentina, and Trucidocynodon riograndensis Oliveira et al., 2010 from Brazil. Herein, a new specimen (skull and mandible) assigned to T. riograndensis from the Carnian of the Candelária Sequence (Southern Brazil) is described. A phylogenetic analysis recovered the new specimen as the sister taxon of the holotype of T. riograndensis, and both in a trichotomy with E. lunensis and D. elegans, all supporting the monophyly of Ecteniniidae. The new specimen of T. riograndensis is almost 20% larger than its holotype. Therefore, it represents one of the largest specimens of a carnivorous probainognathian from the Late Triassic known to date and contributes to knowledge of size variation in ecteniniids.


Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by


2017 ◽  
Vol 7 (1) ◽  
pp. 1127-1129
Author(s):  
A Ghosh ◽  
G Ghartimagar ◽  
S Thapa ◽  
MK Shrestha ◽  
OP Talwar

Extracranial meningiomas may be subdivided into primary and secondary types based on absence or presence of intracranial attachments respectively. Primary sinonasal tract meningiomas are rare with unknown etiopathology and non-specific clinical presentation. Of these PEMs only 11.5% are in the nasal cavity and nasal septum. To our knowledge less than 50 cases of PEM of nasal cavity have been reported in the literature. We report a case of a 22 years old male who presented with epistaxis and increasing nasal stuffiness for the last one year.


Author(s):  
Amanzhol Kusainovich Dnekeshev

This article presents the morphometric rationale for changes in the nasal bone of a Bactrian camel in an age aspect. The nasal bone is present in the Bactrian camel, as in all farm and domestic animals, with a flat, paired bone, which is involved in the formation of the roof of the nasal cavity. Anatomically on the nasal bone, the outer and inner surfaces are distinguished. Changes in the length and width of the left and right sides of the interosseous sutures of the nasal bone in the Bactrian camel are similar in age.    


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