Maxillary Fragments Research Articles

Immunoexpression pattern of autophagy mediators in alveolar bone osteoclasts following estrogen withdrawal in female rats.

It is known that estrogen deficiency increases osteoclast formation and activity. Autophagy, a cell survival pathway, has been shown to be crucial for osteoclast function. However, little is known about the effects of estrogen depletion on osteoclast autophagy. Here, we evaluated the effects of estrogen deficiency in the immunoexpression of autophagy mediators in alveolar bone osteoclasts of ovariectomized rats. Twelve adult female rats were ovariectomized (OVX-group) or SHAM-operated (SHAM-group). After three weeks, the rats were euthanized and maxillary fragments containing alveolar bone of the first molars were processed for light microscopy or transmission electron microscopy (TEM). Paraffin-sections were subjected to the TRAP method (osteoclast marker) or to the immunohistochemical detections of beclin-1, LC3α, and p62 (autophagy mediators); araldite-sections were processed for TEM. The number of TRAP-positive osteoclasts and the number of immunolabeled-multinucleated cells (MNCs) along the alveolar bone surface of the first molar were computed. The number of TRAP-positive osteoclasts and the number of beclin-1-, LC3α- and p62-immunolabelled osteoclasts were significantly higher in OVX-group than the SHAM-group. MNCs were frequently located juxtaposed to Howship lacunae along the alveolar bone surface, indicating that these cells are osteoclasts. TEM revealed osteoclasts exhibiting autophagosomes. Our data indicate that autophagy plays an important role during estrogen deficiency-induced osteoclastogenesis. Thus, our results contribute to a better understanding on the role of autophagy on osteoclasts under estrogenic deficiency, and reinforce the idea that modulation of autophagy may be a useful tool to inhibit excessive oral bone resorption in post-menopausal women.

A new species of extinct False Vampire Bat (Megadermatidae: Macroderma) from the Kimberley Region of Western Australia

A new species of False Vampire Bat (Megadermatidae), Macroderma handae sp. nov., is described from dental, dentary and maxillary fragments recovered from limestone deposits at Dingo Gap, Oscar Range, in the Kimberley region of Western Australia. This material is likely to be of Pliocene age, or early Pleistocene, based on biocorrelation within the same sample. The absence of the P2 indicates that it is more derived than Miocene taxa including M. malugara and M. godthelpi, but its phylogenetic position relative to M. koppa could not be determined. It appears to be slightly smaller than M. gigas and M. koppa based on the size of M1 and M2. It can be distinguished from M. gigas by the lesser degree of fenestration in the maxilla; and from all other species of Macroderma by the shape of the protofossa of the M1, plus the M2 protoconid relatively high and of proportionally greater area within the trigonid. Other material collected, but not identified completely or described, includes several lower canines from a species of emballonurid, and a dentary with M1-3 representing a vespertilionid bat. Given the wear striations observed on the M3 of the newly-described Macroderma species, we suggest that it was a predator of small vertebrates, including possibly the chiropteran co-inhabitants of the cave. This new species of Macroderma is the sixth species recognized in the genus so far, and the second from the Pliocene.

Automatic evaluation of the orbital shape after application of conventional and patient-specific implants: Correlation of initial trauma patterns and outcome

PurposeTo evaluate the precision of orbital shape reconstructions using either conventional plates (CPs) or patient-specific implants (PSIs) to treat different types of orbital fractures, and to evaluate their clinical outcomes. MethodsA total of 92 orbital-reconstruction patients were included. Forty-seven patients, treated with PSIs, formed the main group. The remainder, treated with CPs, were the control group. All patients were examined pre- and postoperatively using computerized tomography (CT) and evaluated for enophthalmos and diplopia. Evaluation of differences in orbital shape between damaged and intact orbits after surgery was performed by commercial orbital analysis software. ResultsIn the main group, mean orbital shape difference between damaged and intact orbits after surgery was 0.137 ± 0.8 cm3 (range −1.7–2.3 cm3). In the control group, the mean shape difference was 1.05 ± 1.9 cm3 (range −1.8–8.3 cm3), significantly higher (p = 0.007). Diplopia occurred in seven PSI patients three months after surgery (14.9%) and in thirteen CP patients (28.9%) (p = 0.181). Enophthalmos occurred in five PSI patients (10.6%) and in sixteen CP patients (35.6%) (p = 0.001). ConclusionPrecise orbital reconstruction prevents the development of enophthalmos after trauma in patients with orbital wall fractures. In patients with preserved infraorbital buttresses and posterior orbital ledges, there were no significant clinical differences between PSIs and CPs. For cases requiring cantilevered reconstruction, including those with zigomatic or maxillary fragment repositioning, preference should be given to the PSI procedure for both effectiveness and predictability.

Eremotherium (Xenarthra, Mammalia) materials from the collections of Laboratório de Paleontologia e Evolução and Laboratório de Geologia of Universidade Federal de Goiás

This study presents the first survey of fossil mammal specimens housed at the collections of the Federal University of Goiás. Here, we describe a set of associated femur and vertebrae fragments, one fragment of tibia, and two left and right maxillary fragments, identified as Eremotherium. Despite its fragmentary condition, the size and morphological aspect of the materials show diagnostic characteristics that suggest their relationship with Eremotherium. These new specimens described here contribute to the paleontology of the Goiás State, which may provide future research investments in collections not yet known, which may increase the knowledge on Pleistocene mammals of Central Brazil.

Re-dating Changyang Cave in Hubei province, southern China

Owing to the unearthed left maxillary fragment and left lower premolar fossil in 1950s, Changyang Cave was regarded as an important hominin site where Middle Pleistocene hominins are first discovered in southern China. However, only two bovine tooth fossils have been dated to 194 + 24–20 ka and 196 + 20–17 ka by U-series dating since 1980s. In this work, the stratigraphy of Changyang Cave was re-investigated by applying U–Th dating method for eight new tooth fossils obtained from fossil layer and two carbonate crystal samples from clay cement on the wall of this cave. New dating results showed that the ages of the two carbonate crystals are 256 and 233 ka respectively, and those of the eight tooth fossils are concentrated from 193 ka to 143 ka. Considering the ages of the two previous fossils, new carbonate crystals, and new eight tooth fossils, we suggested that the age range of Changyang hominin is between 196 and 143 ka.

New remains of Elephantidae from the Upper Siwalik subgroup (Plio-Pleistocene) of Pakistan

The Siwalik sequence saw the appearance and spread of the family Elephantidae in the Indian subcontinent during the Plio-Pleistocene epochs. Elephas flourished and underwent species turnover during the Plio-Pleistocene of the Siwalik Group. The newly discovered specimens include serially arranged M2-3 and partial maxillary fragment with M2 of Elephas planifrons, and M3 and partial dp4 of Elephas hysudricus from the Pinjor Formation (Pleistocene) of the Siwaliks. A tusk from the Tatrot Formation (Pliocene) of the Siwaliks, has been assigned to Elephantoidea indet. Based on the comparison with the stratigraphically well-dated mammalian fauna from the various Siwalik localities of the Indian subcontinent, the age of Sardhok, Panjan Sher Shahana and Kurla Sharif range is suggested to be from the Late Pliocene (Piacenzian) to Late Early Pleistocene (Calabrian), and a savannah like environment is suggested for these localities.

New species of Ballusia Ginsburg and Morales, 1998 (Ursidae, Carnivora) from Miocene of Eastern Siberia, Russia

ABSTRACT The new basal ursine bear, Ballusia zhegalloi n. sp., is described from the Early Miocene Tagay 1 locality (Baikal region, Russia) based on isolated M1. Previously described maxillary fragment with M1-2 from the closely synchronous fauna of Khirgis-Nur I in Mongolia, originally referred to Ballusia elemensis, is here included into the new species. The M1 of the new species shares similarities with M1 of previously known Early Miocene European species B. elmensis but is more derived in lower medial cusps, transversally closer spaced medial ridge and lingual cingulum, and by a slightly expressed antero-external angle. The new Asian species shares some derived features with Ballusia orientalis from Early Miocene of China, such as a more rounded M1 outline, and incipient buccal styles in M1. The other characters in the two forms of Asian Ballusia imply their parallel evolution. The Tagay find represents the first record of the genus Ballusia in Russia. It elucidates phyletic affinities of early ursine bears and refines the geographic and stratigraphic range of the genus Ballusia.

Isisfordia molnari sp. nov., a new basal eusuchian from the mid-Cretaceous of Lightning Ridge, Australia.

The Australian Mesozoic crocodyliform record is sparse in comparison to other Gondwanan localities. A single formally-named taxon is known from this interval; Isisfordia duncani (Winton Formation, Albian–Turonian, Queensland). We present a previously undescribed crocodyliform braincase from the Griman Creek Formation (Cenomanian), New South Wales, which we assign to Isisfordia molnari sp. nov. Assignment to the genus is based on the possession of a newly-defined autapomorphy of Isisfordia: a broadly exposed prootic within the supratemporal foramen. A second autapomorphy of I. duncani (maximum diameter of the caudal aperture of the cranioquadrate siphonium approximately one-third the mediolateral width of the foramen magnum, with the lateral wall of the caudal aperture formed exclusively by the quadrate) may also be present in I. molnari; however, definitive recognition of this feature is marred by incomplete preservation. The new taxon is differentiated from I. duncani based on the absence of a median ridge on the parietal, and the lack of characteristic ridges on the parietal that form the medial margin of the supratemporal foramina. Reanalysis of a second specimen (the former holotype of the nomen dubium,‘Crocodylus (Bottosaurus) selaslophensis’) allows for its referral to the genus Isisfordia. Crucial to this reappraisal is the reinterpretation of the specimen as a partial maxilla, not the dentary as previously thought. This maxillary fragment possesses specific characteristics shared only with I. duncani; namely an alveolar groove. However, several key features differentiate the maxillary fragment from I. duncani, specifically the presence of continuous alveolar septa, the thickening of the medial alveolar rim, and the alveolar and crown base morphology. These findings constitute the first evidence of Isisfordia outside of the type locality and indicate its widespread occurrence on the freshwater floodplains along the eastern margin of the epeiric Eromanga Sea during the Albian–Cenomanian.

Northernmost record of the Metatheria: a new Late Cretaceous pediomyid from the North Slope of Alaska

The northernmost record of Metatheria, Unnuakomys hutchisoni gen. et sp. nov., is described from the Pediomys Point locality in Upper Cretaceous (lower Maastrichtian) strata of the Prince Creek Formation cropping out along the Colville River on the North Slope of Alaska, USA (70°N). Based on over 60 specimens (including tooth-bearing dentaries and a maxillary fragment), the new taxon is unusual in having two well-developed stylar cusps in the C position flanking the deepest part of the ectoflexus. To examine the relationship between U. hutchisoni and other metatherians, U. hutchisoni was scored into the taxon character matrix of other studies. Our results corroborate prior studies that suggest the new Alaskan pediomyid. However, in contrast to other studies, we do not recover a sister-group relationship between U. hutchisoni and Pediomys elegans. Rather, our study suggests that U. hutchisoni is more closely allied with Aquilan species Iqualadelphis lactea and ?Aquiladelphis laurae. Teeth of U. hutchisoni greatly outnumber those recovered from other mammals at Pediomys Point, like Late Cretaceous localities in the Western Interior where metatherians are among the most abundant mammalian fossils. However, what differs between Late Cretaceous mid-latitude localities and the assemblage from the North Slope of Alaska is metatherian richness. Whereas other studies have reported up to a dozen species of metatherians from Late Cretaceous mid-latitude North American assemblages, to date all the metatherian teeth collected from Pediomys Point appear to belong to just U. hutchisoni. A sampling bias may play a role in this pattern. This can be tested through additional collection from the Prince Creek Formation. However, the abundance of U. hutchisoni at Pediomys Point implies that this tiny metatherian thrived in an environment well above the Arctic Circle whose climatic extremes may have acted as a biogeographical filter to other metatherians. As the first mammal to be described from the Prince Creek Formation, U. hutchisoni provides support for the existence of a northern high-latitude early Maastrichtian faunal province identified by others on the basis of its distinctive dinosaurian fauna – the Paaŋaqtat Province.http://zoobank.org/urn:lsid:zoobank.org:pub:0EF38E01-2FF4-4698-A3AD-97CF2EE6847A

First record of the Miocene hominoid Sivapithecus from Kutch, Gujarat state, western India.

Hominoid remains from Miocene deposits in India and Pakistan have played a pivotal role in understanding the evolution of great apes and humans since they were first described in the 19th Century. We describe here a hominoid maxillary fragment preserving the canine and cheek teeth collected in 2011 from the Kutch (= Kachchh) basin in the Kutch district, Gujarat state, western India. A basal Late Miocene age is proposed based on the associated faunal assemblage that includes Hipparion and other age-diagnostic mammalian taxa. Miocene Hominoidea are known previously from several areas of the Siwalik Group in the outer western Himalayas of India, Pakistan, and Nepal. This is the first record of a hominoid from the Neogene of the Kutch Basin and represents a significant southern range extension of Miocene hominoids in the Indian peninsula. The specimen is assigned to the Genus Sivapithecus, species unspecified.

Amphicyon zhanxiangi, sp. nov., a new amphicyonid (Mammalia, Carnivora) from northern China

ABSTRACTThe East Asian records of Amphicyon are rare, fragmented, and unclear. Heretofore, no material could be definitely assigned to this genus. Here, we report a maxillary fragment with P4–M2 and the M3 alveolus from the early middle Miocene Dingjia’ergou fauna, Tongxin, northern China. The enlarged and anteroposteriorly elongated M2 clearly allows us to assign the specimen to Amphicyon as Amphicyon zhanxiangi, sp. nov. The new species is closest to European A. giganteus (e.g., presence of the parastyle and a posteriorly located protocone of P4) and represents an immigrant from Europe during the late early or the earliest middle Miocene. The morphological differences between Amphicyon zhanxiangi, Amphicyon ulungurensis, and North American Amphicyon species suggest at least three dispersal events of the genus from Europe to East Asia during the early and middle Miocene. Amphicyon sp. from the late Miocene site in the Lower Irrawaddy near Magway, Myanmar, shares the enlarged and anteroposteriorly elongated M2 with Amphicyon zhanxiangi and could be a descendant of the latter species.

Reporte del hallazgo de restos de Hilarcotherium sp. (Mammalia, Astrapotheria) y de material asociado en una nueva localidad fosilífera del valle inferior del Magdalena, ciénaga de Zapatosa, Cesar, Colombia

En abril de 2018 el Museo Geológico “José Royo y Gómez” recibió el reporte del hallazgo de material paleontológico en cercanías del corregimiento de La Mata, en el municipio de Chimichagua (Cesar), a orillas de la ciénaga de Zapatosa. El material recolectado por pobladores del lugar incluía un gran diente de caimán (Purussaurus), restos de tortugas (Podocnemididae?) y matamata (Chelus), y un fragmento de maxilar de Hilarcotherium sp. (Mammalia, Astrapotheria), conocido previamente por los hallazgos de la especie tipo Hilarcotherium castanedaii (Vallejo-Pareja, et al., 2015) en los estratos del Grupo Honda (Formación La Victoria) en el municipio de Purificación, Tolima, y de Hilarcotherium miyou (Carrillo, et al., 2018) de la Formación Castilletes, al sureste de la península de La Guajira. Además, este informe constituye el primer registro de rocas continentales del Mioceno en esta región del país. © 2018. Acad. Colomb. Cienc. Ex. Fis. Nat.

A high-latitude fauna of mid-Mesozoic mammals from Yakutia, Russia.

The Early Cretaceous (?Berriasian-Barremian) Teete vertebrate locality in Western Yakutia, East Siberia, Russia, has produced mammal remains that are attributed to three taxa: Eleutherodontidae indet. cf. Sineleutherus sp. (Haramiyida; an upper molariform tooth), Khorotherium yakutensis gen. et sp. nov. (Tegotheriidae, Docodonta; maxillary fragment with three molariform teeth and dentary fragment with one molariform tooth), and Sangarotherium aquilonium gen. et sp. nov. (Eutriconodonta incertae sedis; dentary fragment with one erupted molariform tooth and one tooth in crypt). This is the second occurrence of Mesozoic mammals in high latitudes (paleolatitude estimate N 63–70°) of the Northern Hemisphere. In spite of the presumed Early Cretaceous age based on freshwater mollusks, the Teete mammal assemblage has a distinctive Jurassic appearance, being most similar to the Middle-Late Jurassic mammal assemblages known from Siberia, Russia and Xinjiang, China. The smooth transition from Jurassic to Cretaceous biota in Northern Asia is best explained by stable environmental conditions.

Biodentine and MTA modulate immunoinflammatory response favoring bone formation in sealing of furcation perforations in rat molars.

Evaluate the tissue reaction of periodontium subjacent to furcation perforations in rat molars sealed with Biodentine or mineral trioxide aggregate (MTA). The pulp chamber floor of right upper first molars of 60 rats was perforated and filled with Biodentine, MTA, or cotton pellet (sham); the left first molars were used as control. After 7, 15, 30, and 60days, maxillary fragments were processed for paraffin-embedding. The periodontal space (PS), volume density of inflammatory cells (VvIC) and fibroblasts (VvFb), number of osteoclasts, and collagen content were obtained. Interleukin-6 (IL-6) and osterix (osteoblast marker) were detected by immunohistochemistry. The data were submitted to ANOVA and Tukey's test (p ≤ 0.05). At 7days, high values in VvIC, IL-6-immunolabeled cells, and osteoclasts were accompanied by reduced collagen content in enlarged PS of experimental groups. At all periods, VvIC, number of osteoclasts and IL-6, and PS were higher in sham than in Biodentine and MTA (p < 0.0001). From 7 to 60days, significant reduction in VvIC, IL-6 immunoexpression, and osteoclasts was accompanied by significant increase in VvFb, osteoblasts, and collagen in Biodentine and MTA groups. At 60days, significant differences in VvIC, PS, IL-6, osteoclasts, and osteoblasts were not found between Biodentine and MTA. Significant differences in the osteoclast number were not observed among Biodentine, MTA, and control groups while osteoblasts number was higher in Biodentine and MTA groups. Despite the initial inflammatory reaction and bone resorption, the sealing of furcation perforations with Biodentine and MTA favors the repair of periodontal tissues. Biodentine and MTA exhibit potential as repair material in the treatment of furcation perforations.

New Paleogene Notohippids and Leontiniids (Toxodontia; Notoungulata; Mammalia) from the Early Oligocene Tinguiririca Fauna of the Andean Main Range, Central Chile

Here we describe three new notohippid notoungulate species from the early Oligocene-aged Tinguiririca Fauna (Tinguirirican SALMA), recovered from volcaniclastic deposits of the Abanico Formation in the central Chilean Andes, two of which are known from material sufficiently complete to warrant formal naming. These include Eomorphippus bondi, sp. nov., a form of moderate size distinguished by hypsodont incisors and cheekteeth, as well as distinctive proportions of the upper incisors. A closely similar but more diminutive form is described as Eomorphippus neilopdykei, sp. nov. A third previously unrecognized notohippid in the Tinguiririca Fauna, best represented by a large, low-crowned, lower incisor battery, almost certainly represents a new taxon, but remains too fragmentary to warrant naming now. We also propose a new binomial for a previously named notohippid, ?Eomorphippus pascuali, originally described from Gran Barranca in Argentina but which is now also recorded in Chile. This taxon, here named Rosendo pascuali, is markedly less hypsodont than E. bondi and E. neilopdykei and retains lingual cingula on at least p4-m1. As least one leontiniid notoungulate occurs in the Tinguiririca Fauna, Termastherium flacoensis, gen. et sp. nov., best represented by two partial upper cheek toothrows and a tentatively referred maxillary fragment bearing three deciduous teeth. Collectively, description of these new fossils from Termas del Flaco, Chile helps to more fully characterize the Tinguiririca Fauna, facilitating correlation and comparison to other South American land mammal faunas spanning the Eocene-Oligocene transition.

The primate remains from Roc de Santa (Late Eocene, NE Spain) revisited: New taxonomic allocation

The scarce primate remains from the late Eocene locality of Roc de Santa (Central Pyrenees, NE Spain) were first documented in 1975. This material included a mandibular fragment with P3-M2 and a maxillary fragment with P3-M3 assigned to Adapis magnus (later transferred to the genus Leptadapis), and an isolated M3 attributed to Necrolemur antiquus. However, these specimens were never described in detail. We have thoroughly studied these specimens, with the exception of the mandibular fragment, which has been lost. The maxillary fragment is much smaller than in Leptadapis magnus and shows clear morphological differences from that species; this specimen is assigned to Microchoerus hookeri. Similarly, the isolated M3 resembles that of M. hookeri in size and morphology, and can therefore be attributed to this taxon. In addition, we describe an upper incisor never reported previously, which can also be allocated to M. hookeri, representing the first description of this tooth for the species. Therefore, we conclude that the previous taxonomic determinations were mistaken and all the available primate specimens from Roc de Santa can be confidently assigned to the species M. hookeri, previously described from the same-age localities of Sossís, Spain, and Eclépens-B, Switzerland.

Can Pallars i Llobateres: A new hominoid-bearing locality from the late Miocene of the Vallès-Penedès Basin (NE Iberian Peninsula)

In the Iberian Peninsula, Miocene apes (Hominoidea) are generally rare and mostly restricted to the Vallès-Penedès Basin. Here we report a new hominoid maxillary fragment with M2 from this basin. It was surface-collected in March 2017 from the site of Can Pallars i Llobateres (CPL, Sant Quirze del Vallès), where fossil apes had not been previously recorded. The locality of provenance (CPL-M), which has delivered no further fossil remains, is located very close (ca. 50 m) to previously known CPL outcrops, and not very far (ca. 500 m in NW direction) from the classical hominoid-bearing locality of Can Poncic 1. Here we describe the new fossil and, based on the size and proportions of the M2, justify its taxonomic attribution to Hispanopithecus cf. laietanus, a species previously recorded from several Vallesian sites of the Vallès-Penedès Basin. Based on the associated mammalian fauna from CPL, we also provide a biochronological dating and a paleoenvironmental reconstruction for the site. The associated fauna enables an unambiguous correlation to the Cricetulodon hartenbergeri – Progonomys hispanicus interval local subzone, with an estimated age of 9.98–9.73 Ma (late Vallesian, MN10). Therefore, CPL-M is roughly coeval with the Hispanopithecus laietanus-bearing localities of Can Llobateres 1 and Can Feu 1, and minimally older than those of La Tarumba 1 and Can Llobateres 2. In contrast, CPL-M is younger than the early Vallesian (MN9) localities of Can Poncic 1 (the type locality of Hispanopithecus crusafonti) as well as Polinyà 2 (Gabarró) and Estació Depuradora d’Aigües Residuals–Riu Ripoll 13, where Hispanopithecus sp. is recorded. The associated fauna from CPL indicates a densely forested and humid paleoenvironment with nearby freshwater. This supports the view that Hispanopithecus might have been restricted to dense wetland forests soon before its extinction during the late Vallesian, due to progressive climatic deterioration. Coupled with the existence of other fossiliferous outcrops in the area, this find is most promising for the prospect of discovering additional fossil hominoid remains in the future.

Small-sized mesotheriines (Mesotheriidae, Notoungulata) from Northwestern Argentina: Systematic, chronological, and paleobiogeographic implications

The Neogene outcrops in Northwestern Argentina have provided many fossil mammals, particularly notoungulates. However, the fossil record of the early stages of the late Miocene is scarce. The present study describes two mesotheriine specimens from Las Arcas Formation (underlying the Chiquimil Formation dated at 9.14 ± 0.09 Ma; Catamarca Province) and Saladillo Formation (dated at 10 ± 0.3 Ma; Tucumán Province), represented by a left maxillary fragment with complete M1–3 and a right isolated M3, respectively. The main feature of these pieces is their small size, significantly smaller than that of the Miocene genera Eutypotherium, Typotheriopsis, and Pseudotypotherium, recorded in Argentina. In contrast, these mesotheriines are closer to specimens known from Bolivia. The comparative analysis allows us to refer the material herein described to Plesiotypotherium aff. P. achirense and Mesotheriinae indet., with all cautions inherent to the incompleteness of the material. In turn, the paleobiogeographic implication of these new records is approached. A relationship concerning phylogenetic aspects, size, temporal range, and distribution pattern is proposed, taking into account the small size of the studied material in a temporal context of medium to large-sized mesotheriines.

A new species of Xotodon (Notoungulata, Toxodontidae) from northwestern Argentina

ABSTRACTXotodon caravela, a new species of toxodontid from northwestern Argentina, is presented. The material studied consists of a well-preserved and nearly complete mandible and a maxillary fragment, recovered in the Aconquija Formation (late Miocene-early Pliocene) at the El Molino locality (Tucumán Province, Argentina). The fossil diversity of the levels is concordant with an early Pliocene fauna. The general features of the dentition and mandible (e.g., concave ectoloph and single lingual fold on upper molars, anterior fold mesially displaced relative to the hypoflexid in the lower molars, sigmoid lateral outline of chin, and continuous enamel on M3) allow the inclusion of this specimen in the genus Xotodon. In turn, some traits indicate unequivocally that this is a new species, such as the anterior region without constriction at the premolar level, the approximately 13° angle of implantation of the i3 in relation to the ventral edge of the mandibular body (without lateral divergence), and the presence of an intra-alveolar projection of the incisive crown extending laterally below the premolars to the level of the p4 and forming a robust projection or lateral ledge. The new taxon was included in a matrix of 59 characters and compared with 32 notoungulate genera. The phylogenetic position and comparative analysis support the taxonomic interpretation of the studied specimen as a new species of Xotodon. This represents the first record of a toxodontid in the Neogene lowlands of northwestern Argentina and contributes to our knowledge of this family in the region.Citation for this article: Armella, M. A., D. A. García-López, and L. Dominguez. 2018. A new species of Xotodon (Notoungulata, Toxodontidae) from northwestern Argentina. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1425882.

New fossils of Australopithecus anamensis from Kanapoi, West Turkana, Kenya (2012–2015)

Kanapoi, Kenya, has yielded the earliest evidence of the genus Australopithecus, Australopithecus anamensis. Renewed fieldwork from 2012 through 2015 yielded 18 new fossils attributable to this species. The new specimens include the second maxillary fragment known from a Kanapoi hominin and the first from a relatively young adult. The new maxilla has the distinctive rounded nasal aperture margin characteristic of A. anamensis. A second partial proximal tibia from the site is the first postcranial element from a small A. anamensis individual. A new partial mandible and complete mandibular dentition display distinctive Kanapoi hominin morphology, but the mandible displays a larger trigonid on its fourth premolar than any known so far. Two new complete sets of mandibular incisors are also notably large, especially the lateral ones, a distinctive feature of A. anamensis compared with Australopithecus afarensis. The new fossils also highlight the distinctive morphology of Kanapoi A. anamensis compared to later hominins.