Maxillary Fragments Research Articles

The last piece of the puzzle, the DP4 of Cephalomys arcidens (Rodentia, Caviomorpha) from the late Oligocene of Patagonia (Argentina)

ABSTRACT Deciduous dentition of extinct mammals has traditionally received little attention based on its poor representation in the fossil record. However, several aspects related to this tooth locus could have important evolutionary significance (time of replacement, retention throughout life, and morphology). In this work, we described a new specimen from late Oligocene levels of Cabeza Blanca (Chubut Province, Argentina). This fossil corresponds to a maxillary fragment with a deciduous premolar (DP4) assigned herein to Cephalomys arcidens based on morphological characteristics, size, and comparisons with other late Oligocene-Early Miocene caviomorphs. It can be identified as a DP4 due to its mesiodistally longer than wide diameter, shallow flexi, complex tooth morphology, and its position in the maxillary fragment. This is the first description of the DP4 of a Cephalomyidae and the last unknown dental locus of Cephalomys arcidens. Now, C. arcidens is one of the better-known late Oligocene caviomorphs since it is recognised through the complete dentition, crania, and mandibles. In addition, this new information would be used to evaluate the importance of deciduous dentition in resolving phylogenetic relationships in the enigmatic cephalomyids in particular and in Caviomorpha in general.

New fossils of Tragoportax and Gazella from Padhri, Pakistan, and comments on these genera in the Siwaliks

ABSTRACT Here, we describe new bovid remains from the Late Miocene-Early Pliocene of Padhri in the Potwar Plateau of Pakistan. A comparison with the closely allied genera from the Siwaliks revealed that a maxillary fragment and a hemimandible belong to Tragoportax punjabicus, two isolated teeth can be assigned as cf. Tragoportax sp. and a mandible fragment belongs to Gazella lydekkeri. We suggest that Tragoportax is represented by two valid species and Gazella by three species. The extinction of Tragoportax and Gazella from the Siwaliks during the Early Pliocene could be associated with habitat loss, as these used to live in forest and shrublands respectively which were replaced with the grassland towards the beginning of the Pliocene.

A Novel Minimally Invasive and Cost-Effective Internal Fixation of the Le Fort I Fracture by Using Intermaxillary Fixation Screw and Wire: A Technical Note.

Le Fort I fractures represent a significant proportion of craniofacial trauma, often occurring alongside other injuries to the craniomaxillofacial region. Management options include open reduction and internal fixation (ORIF) or skeletal suspension, each with its limitations and considerations. This technical note presents a novel technique for managing isolated Le Fort I fractures using intermaxillary fixation (IMF) screws, offering a minimally invasive alternative to ORIF. The technique involves the strategic placement of IMF screws in the stable zygomatic bone, coupled with arch bar fixation and wire manipulation for maxillary fragment reduction. This approach is cost-effective, can be performed under local anesthesia, and provides stability without the need for prolonged maxillomandibular fixation (MMF). The simplicity and efficacy of this technique make it suitable for emergency settings and cases where traditional approaches may not be feasible. However, this technique is only feasible in isolated Le Fort I fractures and is contraindicated in comminuted Le Fort I fractures and in edentulous patients with upper jaw involvement.

New material of Lophiparamys debequensis from the Willwood Formation (early Eocene) of Wyoming, including the first postcrania of the genus

Abstract We report new material of the rare early Eocene rodent Lophiparamys debequensis Wood, 1962 from the Willwood Formation of the southern Bighorn Basin, north-central Wyoming. The new material constitutes the first record of L. debequensis from the Bighorn Basin and documents aspects of the anatomy of Lophiparamys that were previously unknown, including a portion of the maxilla and a portion of the tarsus. The maxillary fragment demonstrates that Lophiparamys has a small P3 and a relatively large infraorbital canal. The tarsus of Lophiparamys is similar to that of other early rodents but differs in a few features that suggest an arboreal locomotor repertoire, including an asymmetric astragalar trochlea, long astragalar neck, transverse astragalar sustentacular facet, short calcaneal tuber, elongate calcaneal ectal facet, and circular calcaneal cuboid facet. The presence of arboreally adapted features in the tarsus of Lophiparamys is consistent with a hypothesized relationship between small-bodied Eocene microparamyine rodents and extant Gliridae. Phylogenetic analysis fails to consistently support this relationship or monophyly of Microparamyinae, but both remain plausible. Comparison of L. debequensis with other species of the genus emphasizes the distinctiveness of L. debequensis and suggests the presence of multiple lineages of Lophiparamys.

Two new species of ektopodontid marsupial from the lower deposits of the Etadunna Formation (latest Oligocene), South Australia and a phylogenetic hypothesis for the Ektopodontidae

Molar morphologies of the latest Oligocene genera, Chunia and Ektopodon, are easy to distinguish, but species determinations are more difficult. As more specimens have been collected, more maxillary fragments with molars and/or alveoli and a portion of the rostrum preserved are available. With a suite of maxillae now known, new ektopodontid features have revealed themselves, including the shortening of the rostrum compared to other families of contemporary possums. The facial angulation represented by the flexure of the rostrum at the boundary between P3 and the molar row results in the rostrum being angled differently than the molar row. Ektopodontids have a significantly greater angulation and thus shorter faces, compared to that seen in contemporary phalangeriform possums. Two new species of the genus Chunia, from the lower Etadunna Formation, South Australia, can be distinguished from the type species, Chunia illuminata, of the Ditjimanka Local Fauna. Differences in molar morphologies and the degree of facial angulation distinguish a new species of Chunia from the lowest faunal zone and the Minkina Local Fauna (facial angulation of 52°) from C. illuminata from the next higher faunal zone (Ditjimanka Local Fauna), which has a greater facial angulation of 63°, while a second new species of Chunia, also from the Dijimanka Local Fauna, has a facial angulation of 58° and intermediate molar traits. The degree of facial shortening is a valid discriminator between species of ektopodontid marsupials as it coincides with the species level differences in dental morphology. Additionally, C. omega from the Tarkarooloo Local Fauna is placed in new genus, Ngathachunia, as it is outside of the hypodigms for both of the previously described genera, Chunia and Ektopodon. A well-supported phylogenetic hypothesis for the family indicates the species of Ektopodon form a monophyletic clade, while the species of Chunia are paraphyletic.Judd A. Case [jcase@ewu.edu], Department of Biology, Eastern Washington University, Cheney, WA 99004, USA. Case, J.A., Month, 202X. Two new species of ektopodontid marsupial from the lower deposits of the Etadunna Formation (latest Oligocene), South Australia and a phylogenetic hypothesis for the Ektopodontidae. Alcheringa XXX, X–X. ISSN 0311-5518.

Strength and deformity of the osteosynthesis system of a damaged upper jaw with orthodontic apparatus

Mathematical modeling was used to determine the stress-strain state of the developed simulation model of the biomechanical system "Orthodontic appliance – maxilla". The patterns of changes in the stress state were determined and the values of deformation displacements in the structural elements of the biomechanical system were determined under a force stress of the orthodontic device with an amplitude of 50 N. The strength and strain changes of the mutual location of unfused maxillary fragments and the orthodontic appliance of a given type were evaluated using the data of a numerical experiment. Simulation computer modeling of the stress-strain state of the system showed that activation of the kinematic mechanism of the appliance with a force of 50 N causes the emergence of a complex stress-strain state of midface bones, which contain tensile, compressive, shear and torsion deformations. Equivalent von Mises stresses in the maxillary bone tissue are distributed unevenly. When the orthodontic appliance is activated, there is an asymmetry in the distribution of stresses between the right and left sides both for the appliance itself and for the maxillary bone tissue. When the appliance is activated with a force of 50 N, the stresses in the base of the appliance and bone tissue do not exceed the maximum permissible values.

Middle Miocene “Giraffa” from the Chinji Formation of Siwaliks, Pakistan

A comprehensive record of unique and endemic species of “Giraffa” priscilla has been documented and reported from the Chinji Formation of Lower Siwaliks, Pakistan. The material comprises incisors, canines, premolars, molars, mandibular and maxillary fragments which have been recovered from the Middle Miocene localities of Dhok Bun Ameer Khatoon, Rakh Wasnal, Bhelomar, and Lawa, Punjab, Pakistan. “Giraffa” priscilla is a primitive species of giraffids, having a broad crown, strong styles, and median ribs.

A giant dromaeosaurid theropod from the Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan and the status of Ulughbegsaurus uzbekistanensis

AbstractThe Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan has yielded many isolated bones and teeth representing a variety of non-avian theropod dinosaurs. A pedal phalanx II-2 indicates the presence of a dromaeosaurid theropod that attained a larger body size than any previously known member of that clade. The same formation also yielded a large maxillary fragment that has recently been described as a neovenatorid carcharodontosaurian (Ulughbegsaurus uzbekistanensis). However, this specimen lacks unambiguously diagnostic features of that clade, and its purported carcharodontosaurian characters are either taphonomic artefacts or also shared by dromaeosaurids. Thus, the phylogenetic relationships of Uleghbegsaurus uzbekistanensis remain uncertain. A giant dromaeosaurid occurred together with the medium-sized tyrannosauroid Timurlengia euotica in the Bissekty assemblage.

Chasmaporthetes lunensis (Hyaenidae, Carnivora) from the Early Pleistocene of Crimea

A maxillary fragment of the extinct hyena Chasmaporthetes lunensis (Del Campana, 1914) is described from the Early Pleistocene locality of the Taurida cave (Crimea, Late Villafranchian, 1.8-1.5 Ma). The species was a typical representative of the Villafranchian faunas of Eurasia. This is the first record of the genus Chasmaporthetes in the Pleistocene of Crimea.

The northernmost Eurasian Miocene beavers: Euroxenomys (Castoridae, Mammalia) from Olkhon Island, Lake Baikal (Eastern Siberia)

The castorid dental material described in this paper derives from Miocene, fossiliferous deposits of the Baikal rift valley, exposed at Tagay Bay on Olkhon Island in the Lake Baikal, in eastern Siberia. It consists of maxillary fragments and isolated upper and lower teeth of the small trogontheriine beaver Euroxenomys minutus (von Meyer, 1838). It is the first record of the species in Asia and at the same time the northernmost occurrence of Eurasian Miocene beavers. The magnetostratigraphic correlation of the Tagay -1 section, indicates a late Burdigalian, Early/early Middle Miocene age of ~16.5 to ~16.3 Ma that corresponds to the Mammalian Neogene zone MN4/5. The presence of E. minutus in Tagay is an indicator for an Orleanian European-Siberian bioprovince during the Mid-Miocene Climate Optimum, and for a continuous belt of humid, warm-temperate to subtropical forests, stretching from Europe to Siberia, and probably further to East and South-Eastern Asia. In Eurasia, beaver remains are an indicator of permanent water bodies, which is in agreement with the palaeoenvironment of the Tagay locality.

Mugharet el'Aliya: Affinities of an enigmatic north African Aterian maxillary fragment

AbstractObjectivesThis study uses a virtual framework to examine the left maxillary fragment of the juvenile fossil from Mugharet el'Aliya, Morocco, found in association with an Aterian lithic industry. Previously, this fossil had been ascribed to modern humans or the Neanderthal lineage based on its “archaic”/“Neanderthal‐like” features and apparent large size. Here, we conducted a novel 3D shape comparative analysis of the maxillary fragment to clarify its taxonomic affinities with regard to its size and ontogeny.Materials and MethodsEighty Computed Tomography and surface scans representing ontogenetic samples of Homo sapiens and Homo neanderthalensis were used to capture species‐specific differences. The toolkit of geometric morphometrics in combination with surface registration and an elastic iterative closest point algorithm were used to create a dataset of meshes with an identical number of corresponding vertices for the maxillae. Multivariate statistics were applied to Procrustes superimposed coordinates derived from the vertices of this dataset.ResultsOur analysis showed affinities of the Mugharet el'Aliya individual with our H. sapiens sample, especially with a subadult individual from Qafzeh. No size‐independent affinities with Neanderthals of comparable dental age could be identified.DiscussionOur results add to the evidence connecting fossils from western Asia, especially Qafzeh and Skhul, and the North African Aterian. Furthermore, Mugharet el'Aliya adds to our knowledge of the ontogenetic development of adult morphology that is frequently used to characterize hominin groups, for example, Neanderthals and modern humans.

A new proterotheriid (Mammalia, Litopterna) from the Salla Beds of Bolivia (upper Oligocene): phylogeny and litoptern patellar pit knee locks

ABSTRACT The Salla Beds of Bolivia reveal a rich, late Oligocene (Deseadan, South American Land Mammal “Age”) fauna composed of at least 50 mammalian species. Many taxa (e.g., rodents and typotherian notoungulates) are represented by dozens to hundreds of specimens. Litopterns are much less common but are represented by one macraucheniid and two adianthid species. Until now, only fragmentary postcrania of proterotheriids have been described from Salla. The recent discovery of a maxillary fragment with two molars, examination of previously recovered mandibular fragments, and a phylogenetic analysis, allow us to recognize Promylophis cifellii gen. et sp. nov. It is characterized by small size, absence of a metaconule on M1–2, and lower molars with a short “paracristid” and reduced or absent “paraconid.” Postcranial elements referred to cf. P. cifellii resemble geologically younger (e.g., Miocene) proterotheriids by way of anatomically tridactyl, but functionally monodactyl pes, and distal femora with a supra-trochlear fossa that forms a “patellar pit” that appears to function as a passive stay apparatus for the knee joint. Such a mechanical means of diverting forces from muscle to bone and sinew could save biologically significant amounts of metabolic energy in long-standing animals.

First record of insectivore from the late Oligocene, Kargil Formation (Ladakh Molasse Group), Ladakh Himalayas

The Kargil Formation in the region of Ladakh (northern India) is known for its late Oligocene mammal fauna of both large mammals and rodents. New excavations in the area yielded a maxillary fragment of an insectivore with three premolars and two roots of a canine. The fossil record of the insectivores on the Indian subcontinent is as yet scanty. Based on the peculiar morphology of the last premolar, the Ladakh fossil could be identified as belonging to a new species of Erinaceinae, Ladakhechinus iugummontis n. gen. n. sp. The new find confirms the large diversity among hedgehogs in Asia during the Oligocene.

DIRECT EVIDENCE OF THE MOLARIFORM TOOTH REPLACEMENT IN Gobiconodon borissiaki (GOBICONODONTIDAE, MAMMALIA) FROM THE EARLY CRETACEOUS OF MONGOLIA.

The maxillary fragment of eutriconodontan Gobiconodon borissiaki Trofimov, 1978 (Gobiconodontidae) is described from the Early Cretaceous Zuun-Höövör locality in Mongolia (Övörkhangai aimag, Guchin-Us sum). It demonstrates erupting М2RR (second molariform tooth of the third generation) along with the presence of the almost unworn M4R and alveoli of M3R and M5. This is the first direct evidence of the molariform tooth replacement in Gobiconodon from the Early Cretaceous of Mongolia. The CT study of the specimen revealed the absence of mineralized germs of other teeth.

What can monkey fossils tell us about early human evolution? New insights from the analysis of molar cusp proportions in fossil cercopithecoids from Laetoli, Tanzania

IntroductionLaetoli, Tanzania preserves the earliest fossils attributed to Australopithecus afarensis (3.7 mya). A diversity of non‐human primates including cercopithecoid monkeys have also been recovered. Cercopithecoids provide valuable insights into the paleoenvironments they shared with early humans and, by extension, early hominin paleobiology. Although cercopithecoid fossils at Laetoli represent both more omnivorous cercopihecines and more folivorous and arboreal colobines, the former is more abundant. The diversity and proportion of cercopithecoids figures prominently in debate over the prevalence of closed woodland/forested environments vs more open scrub/bushland. This study uses dental morphometrics to establish the morphological affinity of molar crowns from additional cercopithecoid craniodental fossils recovered from Laetoli localities 1, 2, 6 and 7 to clarify the paleoenvironmental context of our early human ancestors.MethodsStandard linear metric data (mesiodistal length, buccolingual breadth) were collected using dental calipers and total occlusal and individual cusp areas (mm2) were obtained for all molar crowns in an extant cercopithecoid sample (n=90; 18 genera) using high‐resolution 2D images and ImageJ. These data are a comparative baseline for a fossil cercopithecoid sample including a complete (LP) mandible (M1‐M3), maxillary fragment (M1‐M3) and four isolated maxillary molars (n=3 M1’s, n=1 M2). Discriminant function analysis (DFA) using subfamily (n=2 groups) and tribe (n=5 groups) was used to predict group membership and morphological affinity of the fossil sample.ResultsDFA results indicate that predictive accuracy is highest when subfamily is used as the grouping variable and ranges from 62.8% (M3) to 87.2% (M2). Mandibular molars more reliably segregate subfamilies (77.1% ‐ 87.2%) than do maxillary molars (64.4% ‐ 70.2%). The associated mandibular molars group are most closely associated with African colobines. All maxillary specimens cluster with cercopithecines and, more specifically, the papioni. Colobines have expanded hypoconids and metacones but reduced metaconids, entoconids and paracones relative to cercopithecoids.ConclusionMolar cusp proportions discriminate colobines from cercopithecines. This study provides additional evidence for the continued presence of both groups in the upper beds at Laetoli and confirms that the complete LP mandible is most closely aligned with the Colobinae.The presence of a large colobine is consistent with palaeoecological reconstructions supporting the significant presence of closed woodland/forested habitats.SignificanceDespite obligate bipedalism, early hominins retain numerous upper limb and torso adaptations consistent with the use of arboreal substrates. The continued presence of colobines at Laetoli confirms the presence of closed woodland/forested environments and suggests that Au. afarensis at Laetoli may have potentially exploited a variety of habitats including arboreal substrates.

Early Neanderthals in contact: The Chibanian (Middle Pleistocene) hominin dentition from Velika Balanica Cave, Southern Serbia

Neanderthals are Eurasian fossil hominins whose distinctive morphology developed in the southwestern corner of Europe and later spread throughout the continent, reaching Southwest Asia before the Late Pleistocene and spreading into Central Asia by 59–49 ka. The timing, tempo, and route of the Neanderthal movements eastward are poorly documented. The earliest probable evidence of Neanderthals in Asia comes from Karain E Cave (Anatolia, Turkey), dated to 250–200 ka. We present four Chibanian (Middle Pleistocene) hominin specimens, representing at least two individuals, from Velika Balanica Cave (Serbia): a permanent upper third molar (BH-2), a deciduous upper fourth premolar (BH-3) refitted to a poorly preserved maxillary fragment with the permanent first molar in the alveolus (BH-4), and a permanent upper central incisor (BH-5). We provide descriptions of the teeth, as well as a comparative analysis of the well-preserved M1 (BH-4), including assessments of cusp angles, relative occlusal polygon area, relative cusp base areas, two- and three-dimensional enamel thickness, and taurodontism. Morphology of both the occlusal surface and the enamel dentine junction of the M1 indicates that the maxillary fragment and associated dP4 belonged to an early Neanderthal child. The heavily worn I1 and M3 are consistent with the Neanderthal morphology, although they are less distinct taxonomically. These Chibanian remains with provenance from layer 3a are constrained by two thermoluminescence dates: 285 ± 34 ka and 295 ± 74 ka. They represent the earliest current evidence of Neanderthal spread into the Eastern Mediterranean Area. We discuss these findings in light of recent direct evidence for cultural connections between Southwestern Asia and Southeast Europe in the Chibanian.

Shrews of the Genus Chodsigoa (Soricidae, Lipotyphla) from the Pleistocene of Vietnam.

The first finds of the fossil remains of the members of the genus Chodsigoa outside China are described from the Pleistocene of northern Vietnam. They are assigned to C. caovansunga Lunde, Musser et Son, 2003 (a maxillary fragment with A3-M3, an isolated M1, and a dentary with I1 and P4-M2) from the Middle Pleistocene of the Tham Hai cave (Lang Son Province) and C. hoffmanni Chen et al., 2017 (a maxillary fragment with P4-M2) from the Upper Pleistocene of the Lang Trang cave (Thanh Hoa Province). The described specimens are the first fossil finds of these species. They indicate that representatives of the genus Chodsigoa in Vietnam spread to the south much further in the Pleistocene than today.

Early Pleistocene White-toothed Shrew Crocidura kornfeldi (Lipotyphla, Soricidae) from Crimea.

The remains of the white-toothed shrew Crocidura kornfeldi Kormos, 1934 (one skull fragment with almost complete dentition, the fragmental rostral part of a skull with the left upper incisor, a maxillary fragment, five mandibular fragments and an isolated upper incisor) from the Lower Pleistocene deposits of the Taurida cave in the central Crimea (Belogorsk district, Zuya village) are described. This earliest European species of the genus Crocidura was quite common in the Early Pleistocene of Central Europe and the Mediterranean; for the first time, it is described from Crimea and the entire Eastern Europe.

A New Species of Typhlomys (Platacanthomyidae, Rodentia) from the Middle Pleistocene of Northern Vietnam.

A pygmy dormouse Typhlomys stegodontis sp. nov. is described on the base of the maxillary fragment and isolated teeth from the Middle Pleistocene Tham Hai cave locality in northern Vietnam (Lang Son Province). This first finding of the fossil Platacanthomyidae in Vietnam fills the Middle Pleistocene gap in the paleontological record of the family.

Histomorphometric and immunohistochemical study shows that tricalcium silicate cement associated with zirconium oxide or niobium oxide is a promising material in the periodontal tissue repair of rat molars with perforated pulp chamber floors.

To evaluate the periodontium response to tricalcium silicate (TCS) with zirconium oxide (ZrO2 ) or niobium oxide (Nb2 O5 ) used in the sealing of perforated pulp chamber floors in rat maxillary molars. In eighty rats, the perforations in right maxillary molars were filled with either TCS+ZrO2 , TCS+Nb2 O5 , White MTA (used as a gold standard material) or no repair material was placed (Sham Group, SG); the left molars of SG, were used as controls (CG). Sections of maxillary fragments following 7, 15, 30 and 60days were used to evaluate the volume densities of inflammatory cells (VvIC) and fibroblasts (VvFb), width of the periodontal space, amount of collagen, number of osteoclasts and number of IL-6-immunostained cells. The data were subjected to two-way ANOVA followed by Tukey's test (P≤0.05). At all periods, significant differences in VvIC were not detected among TCS+ZrO2, TCS+Nb2 O5 and MTA groups, which had values significantly lower (P<0.05) than the SG. Significant differences in the number of IL-6-immunolabelled cells were not observed among TCS+ZrO2 , TCS+Nb2 O5 and MTA groups (P>0.05) at 15, 30 and 60days. At 7, 15 and 30days, the number of osteoclast was significantly greater in TCS+ZrO2, TCS+Nb2 O5 and MTA (P<0.05) than in the CG; no significant difference was detected after 60days (P>0.05). The width of the periodontal space and amount of collagen in TCS+ZrO2 and TCS+Nb2 O5 groups were similar to the CG at 30 and 60days while SG specimens had a significant reduction (P<0.05) in the amount of collagen and significant increase (P<0.05) in the width of the periodontal space. TCS+ZrO2 and TCS+Nb2 O5 were associated with periodontium repair since these materials allowed the reestablishment of periodontal space width and collagen formation when used in the filling of uninfected perforations in the pulp chamber floor of maxillary rat molars. Furthermore, the significant reduction in the periodontal space of TCS+ZrO2 and TCS+Nb2 O5 specimens after 60days confirmed that the experimental materials were associated with a more rapid recovery of the injured tissues than MTA.