Lower Jaw Fragments Research Articles

Craniofacial morphology of Adalatherium hui (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar

ABSTRACT The cranium of Adalatherium hui, as represented in the holotype and only specimen (UA 9030), is only the second known for any gondwanatherian mammal, the other being that of the sudamericid Vintana sertichi. Both Adalatherium and Vintana were recovered from the Upper Cretaceous (Maastrichtian) Maevarano Formation of northwestern Madagascar. UA 9030 is the most complete specimen of a gondwanatherian yet known and includes, in addition to the cranium, both lower jaws and a complete postcranial skeleton. Aside from Adalatherium and Vintana, gondwanatherians are otherwise represented only by isolated teeth and lower jaw fragments, belonging to eight monotypic genera from Late Cretaceous and Paleogene horizons of Madagascar, the Indian subcontinent, Africa, South America, and the Antarctic Peninsula. Although the anterior part of the cranium is very well preserved in UA 9030, the posterior part is not. Nonetheless, comparable parts of the crania of Adalatherium and Vintana indicate some level of common ancestry through possession of several synapomorphies, primarily related to the bony composition, articular relationships, and features of the snout region. Overprinted on this shared morphology are a host of autapomorphic features in each genus, some unique among mammaliaforms and some convergent upon therian mammals. The cranium of Adalatherium is compared with the crania of other mammaliamorphs, particularly those of allotherians or purported allotherians (i.e., haramiyidans, euharamiyidans, multituberculates, Cifelliodon, and Megaconus). Particular emphasis is placed on several recently described forms: the enigmatic Cifelliodon from the Early Cretaceous of Utah and several new taxa of euharamiyidans from the Late Jurassic of China.

Complex treatment of periodontitis in patients with fractures of the lower jaw

Relevance. Tooth splints used to immobilize lower jaw fragments lead to the progression of periodontitis.Purpose. To study changes in periodontal tissues in patients with fractures of the lower jaw during immobilization with dentitional double jaw splints.Materials and methods. Patients with periodontitis during the treatment of fractures of the lower jaw were examined.Results. In patients with periodontitis who have a fracture of the lower jaw, inflammatory and destructive processes in periodontal tissues progress during the immobilization of fragments by the orthopedic method (tooth splints).Conclusion. Comprehensive treatment of periodontitis in fractures of the lower jaw, including dynamic magnetotherapy (DMT) and the treatment of periodontal pockets with liniment of cycloferon, reduces the severity of inflammatory and destructive processes in periodontal tissues.

A New Record of Mongoloscapter (Talpidae, Lipotyphla, Mammalia) from the Oligocene of Mongolia

A lower jaw fragment of the mole Mongoloscapter zhegalloi Lopatin, 2002 (Talpidae, Talpinae) from the Late Oligocene Tsakhir-Ula locality (Mongolia, Omnogovi Aimag) is described. This is the second record of Mongoloscapter. This genus is characterized by a lower molar structure that suggests that it should be assigned to the tribe Scaptonychini.

The stem placental mammal Prokennalestes from the Early Cretaceous of Mongolia

All materials, including upper and lower jaw fragments and isolated teeth, of two closely related species of the stem placental mammal Prokennalestes, P. minor Kielan-Jaworowska et Dashzeveg, 1989 (258 specimens) and P. trofimovi Kielan-Jaworowska et Dashzeveg, 1989 (251 specimens), from the type locality of Khovoor (Early Cretaceous of Mongolia) are described. These extensive materials allow for the first time the study of morphological and size variability in an Early Cretaceous mammal. Prokennalestes can be diagnosed by the dental formula I?/4, C1/1, P4–5/5, M3/3, presence of the Meckelian groove, the mandibular foramen positioned dorsally on a prominent longitudinal ridge, presence of the masseteric foramen, double-rooted and premolariform lower canine, submolariform P5 with a large protocone and minute metacone, presence of the preparastyle, cusplike postmetacrista, and cusplike conules with incipient conular cristae on the upper molars, premolariform p5, the protoconid distinctly higher than the metaconid, the paraconid and metaconid connate at the base, transverse protocristid, and presence of distal metacristid on the lower molars. Two Prokennalestes species are reliably distinguished by the tooth dimensions (P. minor is smaller by 20%), the position of the infraorbital foramen (under P4 in P. minor and between P4 and P5 or under P5 in P. trofimovi), the presence of protoconal swelling on P4 (usually absent in P. minor and usually present in P. trofimovi), the ectocingulum extension in M3 (longer in P. minor), position of the posterior end of the mandibular symphysis (under p2 in P. minor, under p2–p3 in P. trofimovi), and by the position of the posterior mental foramen (under p4 in P. minor and under p5 in P. trofimovi). Taking into account considerable morphological differences between the two samples, they are regarded as different species rather than sexual morphs of the same species. Prokennalestes is a basal eutherian mammal similar in phylogenetic position to other stem placentals (Eomaia, Murtoilestes, Bobolestes, Aspanlestes). A more exact phylogenetic position of Prokennalestes can be established based on rigorous phylogenetic analysis including a large set of known stem therian and stem placental taxa.

Fossil peccaries of Late Pleistocene/Holocene (Cetartiodactyla, Tayassuidae) from underwater caves of Serra da Bodoquena (Mato Grosso do Sul State, Brazil)

New records of Catagonus stenocephalus and Tayassu pecari are reported from the karst of Serra da Bodoquena, located at a south-western portion of Brazil near the border with Paraguay. Skull and lower jaw fragments at different stages of mineralisation were retrieved from two limestone underwater caves, Japonês and Nascente do Formoso, associated with clay and sand deposits with no retrievable stratigraphy. C14 dating of fossil mammals from these caves was attempted, but so far no success was achieved, but the inferred age for the associated paleofauna of these caves is Late Pleistocene and Holocene. The morphology of these fossil peccaries, from the most south-western known population in Brazil, is detailed and paleoecological implications are considered.

Juvenile remains of the “woolly rhinoceros” Coelodonta antiquitatis (Blumenbach 1799) (Mammalia, Rhinocerotidae) from the Tomsk Priob'e area (southeast Western Siberia)

Ontogenetic studies based on fossil mammals are rather scarce, including for the “woolly rhinoceros” Coelodonta antiquitatis (Blumenbach 1799). In this paper, for the first time, the earliest age stages (from 6 months to 3.5 years) of C. antiquitatis have been studied on the basis of several lower jaw fragments and limb bones from two Late Pleistocene sites along the Ob' (at Krasny Yar and near Kargasok) in the Tomsk Priob'e area (Tomsk region, southeast Western Siberia). As opposed to other mammalian species (e.g. mammoths), the absence of great concentrations of C. antiquitatis juvenile remains (possibly due to the palaeoecological features of this taxon) has to be emphasized. Finds of skulls, jaws, and isolated milk molars are very rare, particularly in those cases of individuals younger than three years. Therefore, the remains from Krasny Yar, belonging to individuals characterized by different ages, represent a unique case.A large series of osteological material on the mandibles with functioning milk teeth and forming permanent teeth, belonging to calves from 6 months to 3.5 years of age, is described. For the first time, a large series of C. antiquitatis tubular bones of different individual ages (from birth to adulthood) is described, and the order and age of epiphysis adhering is revealed. The proportions of tubular bones (ratio between epiphysis and diaphysis) remain the same in stages 3–5 of individual progress (over 3 years of age). An assumption about C. antiquitatis sizes in different ontogenetic stages and the rate of growth is made. The body size for one-month-old calves is approximately 72 cm in shoulder height and about 120 cm in length. Well-known ontogenetic studies concerning modern African rhinoceroses (Diceros bicornis L. 1756 and Ceratotherium simum simum [Burchell, 1817]) as well as other ontogenetic studies performed on C. antiquitatis juvenile dental material have also been taken into consideration in this paper.

Simojovelhyus is a peccary, not a helohyid (Mammalia, Artiodactyla)

Simojovelhyus pocitosense is based on a lower jaw fragment with three molars from the late Oligocene amber mine deposits near the village of Simojovel, Chiapas Province, Mexico. It is the oldest fossil mammal known from Central America. It was described by Ferrusquia-Villafranca in 2006 as a helohyid, a group of primitive artiodactyls known from the Bridgerian and Uintan (older than 49–42 Ma), yet it comes from early Arikareean deposits about 25–27 Ma, suggesting that it was a very late helohyid living more than 10 m.y. after their apparent Uintan extinction. We re-examined the specimen, and compared it to the large collection of recently described peccaries from the Chadronian (Perchoerus minor) and Orellan (Perchoerus nanus) and Bridgerian helohyids (Helohyus sp.). Once the range of variation of characters in helohyids and peccaries is accounted for, Simojovelhyus shows derived similarities to early peccaries, especially in the bunodont molars with inflated cusps and the configuration of cristids and accessory cuspulids, and none of the incipient lophodonty and primitive morphology seen in helohyids. In fact, the only real similarity other than symplesiomorphies between Simojovelhyus and helohyids is its small size, but it is close to the size range of the tiny Chadronian peccary P. minor. Thus, based on both derived tooth characters and its age, it is much more parsimonious to regard Simojovelhyus as a tiny Mexican peccary from the Arikareean, not a very late helohyid. This removes the anomalously late occurrence of helohyids from the mammalian fossil record, and forces a re-examination of our view of mammalian evolution in Central America.

Diverse new microvertebrate assemblage from the Upper Triassic Cumnock Formation, Sanford Subbasin, North Carolina, USA

The Moncure microvertebrate locality in the Cumnock Formation, Sanford sub-basin, North Carolina, dramatically increases the known Late Triassic age vertebrate assemblage from the Deep River Basin. The ∼50,000 recovered microvertebrate fossils include osteichthyans, amphibians, and numerous lepidosauromorph, archosauriform, and synapsid amniotes. Actinopterygian fossils consist of thousands of scales, teeth, skull, and lower jaw fragments, principally of redfieldiids and semionotids. Non-tetrapod sarcopterygians include the dipnoanArganodussp., the first record of lungfish in the Newark Supergroup. Temnospondyls are comparatively rare but the preserved centra, teeth, and skull fragments probably represent small (juvenile) metoposaurids. Two fragmentary teeth are assigned to the unusual reptileColognathus obscurus(Case). Poorly preserved but intriguing records include acrodont and pleurodont jaw fragments tentatively assigned to lepidosaurs. Among the archosauriform teeth is a taxon distinct fromR. callenderithat we assign toRevueltosaurus olseninew combination, a morphotype best assigned to cf.Galtonia, the first Newark Supergroup record ofCrosbysaurussp., and several other archosauriform tooth morphotypes, as well as grooved teeth assigned to the recently named speciesUatchitodon schneideri. Synapsids represented by molariform teeth include both “traversodontids” assigned to aff.Boreogomphodonand the “dromatheriid”Microconodon. These records are biogeographically important, with many new records for the Cumnock Formation and/or the Newark Supergroup. In particular,Colognathus,Crosbysaurus, andUatchitodonare known from basins of Adamanian age in the southwestern U.S.A. These new records include microvertebrate taxa more typical of non-Newark basins (abundant archosauriforms, temnospondyls, lungfish) as well as more typical Newark osteichthyans and synapsid-rich faunal elements.

Enigmatic new mammals from the late Eocene of Egypt

A new mammalian genus and species from the earliest late Eocene of Egypt is represented by a lower jaw fragment and two isolated lower molars. A rare combination of features and the fragmentary nature of the materials make their taxonomic assignment to either Marsupialia or Chiroptera uncertain. The holotype of the new genus is the best-preserved specimen in the sample, a dentary fragment with two molars that have uncompressed trigonids, weak buccal cingulids, and a nyctalodont arrangement of the hypocristid. Some traits appear to more clearly support marsupial, as opposed to chiropteran, affinities for this species, including the very likely presence of four molars in the dentary. The enamel of an additional lower molar assigned to this species consists of a single layer of radial enamel without any prism decussation, an enamel type that characterizes marsupials as well as chiropterans. A second taxon is represented by two isolated upper molars. Some traits appear to more clearly support marsupial, as opposed to chiropteran, affinities for these species, including the orientation of pre- and postprotocristae, the moderately slender lingual portion of the trigon, and the absence of any talon expansion. As some of these features can be found in various bat clades, chiropteran affinities for these species cannot be ruled out, but we propose that the new taxa are more likely to represent specialized ‘didelphimorphian’ marsupials.

Gobiconodonts from the Early Cretaceous of Oshih (Ashile), Mongolia

We describe here the first discovered mammalian remains from the Mongolian Early Cretaceous locality Oshih (Ashile). Four fragmentary, tooth-bearing specimens, probably corresponding to three individuals, have been recovered. All the fossils can be assigned to the family Gobiconodontidae (Chow and Rich, 1984). The specimens include three lower jaw fragments and one upper jaw fragment, and represent at least two different taxa.Gobiconodon hopsoni n. sp., is described and diagnosed here. This new species is larger than G. ostromi (Early Cretaceous Cloverly Formation, USA); thus, it is the largest triconodont and one of the largest Mesozoic mammals known. Gobiconodon sp., found also at Oshih, is slightly larger than G. borissiaki from the Early Cretaceous of Khoobur, Mongolia, but smaller than G. ostromi The specimens of this second species are poorly preserved and provide insufficient data for a diagnosis.The status of the different species of Gobiconodon and the new gobiconodontid Hangjinia is reviewed. In gobiconodontids and Triconodontidae, the maxillae appear to make a significant contribution to the orbital rim, a condition unusual among basal mammals, in which the lacrimal and jugal are the main components. Other triconodonts such as Jeholodens likely an “amphilestid”, appear to show the primitive mammalian condition for this feature. We present a brief consideration of triconodont relationships and discuss alternative placements of Gobiconodon among Mammaliaformes.

New fossil materials of the earliest new world monkey, Branisella boliviana, and the problem of platyrrhine origins

Branisella boliviana, from the Late Oligocene of Salla, Bolivia, is the oldest fossil platyrrhine monkey discovered. To date, several fossil specimens of Branisella have been obtained, but most of them are fragmentary dentitions, so the animals craniodental morphology is still obscure. During the 1996 field season a pair of upper and lower jaw fragments and another nearly complete mandible were recovered. These new fossil materials reveal the following morphological features in Branisella: 1) P2 is much smaller than P3,4, whereas P2 is relatively small but probably sexually dimorphic; 2) the zygomatic arch protrudes smoothly posterolaterally from the maxillary bone, as in extant Callicebus; 3) the mandibular arcade is nearly V-shaped and the symphysial angle, which is formed by the horizontal plane and the anterior face of mandibular symphysis, is about 40°, i.e., it neither leans as far anteriorly as in callitrichines nor does it stand as vertically as Cebus; 4) upper and lower molars wore down rapidly in life, suggesting a herbivorous diet and the possibility of terrestriality; and 5) dental eruptive sequence is the same as in extant Aotus. As a whole, the dentition of Branisella is very similar to that of Proteopithecus from the Late Eocene of Fayum, Egypt, except in the lower canine morphology, suggesting a close phyletic relationship between them. The origin and early diversification of platyrrhine monkeys might have occurred on the African continent before crossing the Atlantic Ocean. Am J Phys Anthropol 111:263–281, 2000. © 2000 Wiley-Liss, Inc.

New fossil materials of the earliest new world monkey, Branisella boliviana, and the problem of platyrrhine origins.

Branisella boliviana, from the Late Oligocene of Salla, Bolivia, is the oldest fossil platyrrhine monkey discovered. To date, several fossil specimens of Branisella have been obtained, but most of them are fragmentary dentitions, so the animals craniodental morphology is still obscure. During the 1996 field season a pair of upper and lower jaw fragments and another nearly complete mandible were recovered. These new fossil materials reveal the following morphological features in Branisella: 1) P(2) is much smaller than P(3,4), whereas P(2) is relatively small but probably sexually dimorphic; 2) the zygomatic arch protrudes smoothly posterolaterally from the maxillary bone, as in extant Callicebus; 3) the mandibular arcade is nearly V-shaped and the symphysial angle, which is formed by the horizontal plane and the anterior face of mandibular symphysis, is about 40 degrees, i.e., it neither leans as far anteriorly as in callitrichines nor does it stand as vertically as Cebus; 4) upper and lower molars wore down rapidly in life, suggesting a herbivorous diet and the possibility of terrestriality; and 5) dental eruptive sequence is the same as in extant Aotus. As a whole, the dentition of Branisella is very similar to that of Proteopithecus from the Late Eocene of Fayum, Egypt, except in the lower canine morphology, suggesting a close phyletic relationship between them. The origin and early diversification of platyrrhine monkeys might have occurred on the African continent before crossing the Atlantic Ocean.

Vertebrate faunas 49 to 36 million years ago and additions to the species ofLeptoreodon(Mammalia: Artiodactyla) found in Texas

ABSTRACT A comparison of parts of the fossil mammalian faunas of southern California and western Texas with those of the northern Rocky Mountain states, combined with K/Ar dates, permits a division of the Duchesnean land-mammal age into early and late subages. The early Duchesnean fauna is more closely related to the Uintan and the late Duchesnean fauna is more closely related to that of the Chadronian. Leptoreodon major, L. pusillus, L. edwardsi, and L. leptolophus are recognized in late Eocene faunas of western Texas. A lower jaw fragment of L. leptolophus from the Laredo Formation, Claiborne Group, of the Texas Coastal Plain is described.

Upper Dentition of Ekgmowechashala (Omomyid Primate) from the John Day Formation, Oligo-Miocene of Oregon

A fragmentary maxilla of an omomyid primate, probably referable to Ekgmowechashala, is described from the John Day Formation of Oregon. Ekgmowechashala is otherwise known only from lower jaw fragments from South Dakota. Similarities between the John Day specimen and early Oligocene Rooneyia strengthen the probability that Ekgmowechashala evolved from a form closely related to Rooneyia.

A cleft adult mandible and the nine other lower jaw fragments from Makapansgat.

A cleft adult mandible and the nine other lower jaw fragments from Makapansgat.

Nimravides, a New Genus of Felidae from the Pliocene of California, Texas and Oklahoma

The Arnett local fauna from Ellis County, Oklahoma (see Kitts, 1957) includes two remarkably well preserved and complete felid lower jaws. Investigation has revealed that these specimens are very similar to and probably conspecific with material from the Higgins local fauna which has been referred to Machairodus Kaup (see Hesse, 1940) and material from the Black Hawk Ranch local fauna which has been referred to Pseudaelurus Gervais (see Macdonald, 1948). A study of the Arnett, Black Hawk Ranch and Higgins specimens reveals that they are certainly not referable to Machairodus and that, although they bear a number of marked resemblances to the lower jaw of Pseudaelurus , their generic separation from this genus is almost certainly justified. I should like to express my gratitude to Dr. Donald E. Savage of the University of California who allowed me complete access to the specimens in his charge and to Dr. J. R. Macdonald who permitted me to reproduce two figures from his paper on the Black Hawk Ranch carnivores. The plate was prepared by Mr. Irwin Gold. This study was supported by a grant from the faculty research fund of the University of Oklahoma. The following abbreviations are used: O.U.S.M.—J. Willis Stovall Museum of Science and History, University of Oklahoma; U.C.M.P.—Museum of Paleontology, University of California. All measurements are in millimeters. > Family FELIDAE Gray, 1821 > > Subfamily Nimravinae Trouessart, 1885 > > Nimravides gen. nov. > > (Figs. 1, 2; Plate I) Fig. 1 Nimravides thinobates (Macdonald). Type, U.C.M.P. No. 34513, right lower jaw fragment with P3 and M1; a, crown view; b, lateral view; ×½. (After Macdonald). Fig. 2 Nimravides thinobates (Macdonald). U.C.M.P. No. 34512, skull; a, palatal view. b, lateral view. ×½. (After Macdonald). Plate I Nimravides thinobates (Macdonald). a and b , O.U.S.M. No. 36-4-S13, left lower jaw; a , crown view of cheek …

Description of an Upper Molar Tooth of Dichobune cervinum from the Eocene Marl at Binstead, Isle of Wight.

The species of Anoplotherian quadruped described in the ‘Geological Transactions,’ second series, vol. vi. p. 41, and in my ‘British Fossil Mammalia,’ p. 440, under the name of Dichobune cervinum , has hitherto been known only by the fragment of lower jaw with three molars, first described and figured by S. P. Pratt, Esq., F.R.S., in the third volume of the same series of ‘Geol. Trans.,” p. 451. As the lower molar teeth are less characteristic of the aberrant Anoplotheriidæ and less distinct from those of the Ruminantia than the upper one, the opportunity of examining an upper molar tooth of a Dichobune was much to be desired, more especially since Cuvier had not been able to obtain more than one small fragment of the upper jaw, with two premolars, of this subgenus, from the Eocene formations in France. I am indebted to Hugh Strickland, Esq., F.G.S., for the desired opportunity of examining the upper true molar, either first or second of the left side, here figured (figs. 1, 2). It was obtained at Binstead, in the Isle of Wight, from the same quarry as the lower jaw of the Dichobune cervinum above referred to, and it presents exactly the proportions which might be expected in the upper molars of that species; having the same superior transverse diameter, as compared with the antero-posterior diameter, which the upper molars of all herbivorous and most other mammals present, compared with the lower ones. (Compare figs. 1 and 3 with 5 and 6.) The