Chorlakkia hassani, A New Middle Eocene Dichobunid (Mammalia, Artiodactyla) from the Kuldana Formation of Kohat (Pakistan)

117-124http://deepblue.lib.umich.edu/bitstream/2027.42/48496/2/ID347.pd

Reconnaissance Survey and Vertebrate Paleontology of Some Paleocene and Eocene Formations in Pakistan

105-116http://deepblue.lib.umich.edu/bitstream/2027.42/48495/2/ID346.pd

Morphology of the petrosal and stapes of Borealestes (Mammaliaformes, Docodonta) from the Middle Jurassic of Skye, Scotland

We describe, in unprecedented detail, the petros-als and stapes of the docodont Borealestes from the Middle Jurassic of Scotland, using high resolution lCT and phase- contrast synchrotron imaging. We describe the inner ear endocast and the vascularized interior structure of the pet-rosal, and provide the first endocranial view of a docodontan petrosal. Our study confirms some similarities in petrosal and stapedial morphology with the better known Haldan-odon of the Late Jurassic of Portugal, including: (1) the degree of curvature of the cochlea; (2) multiple features related to the highly pneumatized paroccipital region; (3) the shape of lateral trough, the fossa of the M. tensor tym-pani, and the ridge on the promontorium; (4) the round shape of the fenestra vestibuli; and (5) overall morphology of the stapes. But Borealestes differs from Haldanodon in having a bony ridge that separates the tympanic opening of the prootic canal, the secondary facial foramen and the hia-tus Fallopii, from the fenestra vestibuli. We identify two new vascular structures: the anterior and posterior trans-cochlear sinuses, which traverse the pars cochlearis around the cochlear nerve (VIII). These trans-cochlear sinuses have not been observed in previous docodont specimens, and could be an autapomorphy of Borealestes, or apomorphic for this clade. We also establish the anatomical relationship of the circum-promontorium plexus to the inner endocast. The high quality of our scans has made these structures visible for the first time

The mandible and dentition of Borealestes serendipitus (Docodonta) from the Middle Jurassic of Skye, Scotland

The Middle Jurassic docodont Borealestes serendipitus was the first Mesozoic mammal found in Scotland over 40 years ago. Its affinities and morphology have remained poorly understood. Although multiple dentary fragments and isolated teeth have been recovered from Scotland and England, they have not yet been described in sufficient detail. We report new, more complete specimens collected during recent field work on Skye, Scotland, combined with previously collected material. This includes upper and lower dentition and an almost complete right dentary. We present an updated description and diagnosis of the genus Borealestes, based on high-resolution micro-computed tomography (micro-CT) and synchrotron scans. We identify seven key features that distinguish Borealestes from other docodonts, including a pronounced a–c crest, absence of the a–g crest on cusp a, an anterior fovea at the buccolingual midpoint of the upper molar, and the convergence of the Meckel’s groove with the ventral margin of the mandible. We also present a revised diagnosis for the second species, B. mussettae. Our phylogenetic analysis supports a clade formed by Borealestes, Haldanodon, Docofossor, and Docodon. Ontogenetic variation in the mandibular morphology of Borealestes is similar to that seen in Docodon and Haldanodon, with the delayed emergence of the ultimate lower molar, the shift of the last molar to the front of the coronoid process, and a posterior shift of the Meckel’s sulcus in successively older individuals. This supports a distinctive growth pattern in the clade including Borealestes and Docodon, one that may be present in Docodonta as a whole

Phylogenetic placement of Adalatherium hui (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar : implications for allotherian relationships

The phylogenetic position of Gondwanatheria within Mammaliaformes has historically been controversial. The well-preserved skeleton of Adalatherium hui from the Late Cretaceous of Madagascar offers a unique opportunity to address this issue, based on morphological data from the whole skeleton. Gondwanatheria were, until recently, known only from fragmentary dental and mandibular material, as well as a single cranium. The holotype of A. hui provides the first postcranial skeleton for gondwanatherians and substantially increases the amount of character data available to score. We sampled 530 characters and 84 cynodonts (including 34 taxa historically affiliated with Allotheria) to test the phylogenetic relationships of Gondwanatheria and Allotheria using parsimony, undated Bayesian, and tip-dated Bayesian methods. We tested three lower dental formulae for Adalatherium, because its postcanines are distinctly different from those of other mammaliaforms and cannot readily be homologized with any known dental pattern. In all analyses, Adalatherium is recovered within Gondwanatheria, most frequently outside of Sudamericidae or Ferugliotheriidae, which is congruent with establishment of the family Adalatheriidae. The different dental coding schemes do not greatly impact the position of Adalatherium, although there are differences in character optimization. In all analyses, Gondwanatheria are placed within Allotheria, either as sister to Multituberculata, nested within Multituberculata, or as sister to Cifelliodon (and Euharamiyida), or in a polytomy with other allotherians. The composition of Allotheria varies in our analyses. The haramiyidans Haramiyavia and Thomasia are placed outside of Allotheria in the parsimony and tip-dated Bayesian analyses, but in a polytomy with other allotherians in the undated Bayesian analyses

Docodonts from the British Mesozoic

This paper deals with new docodont teeth from the upper Bathonian of Forest Marble, collected by Prof. K.A. Kermack and his team, and from the basal Cretaceous of the Purbeck Limestone Group, collected by P. Ensom. Study of this materialled to the recognition of three new taxa: Borealestes mussettisp. nov. and Krusatodon kirtlingtonensis gen. et sp. nov. from Forest Marble, Peraiocynodon majorsp. nov. from Purbeck; this makes the Bathonian locality the richest (four species) docodont locality so far known. The possible synonymy of Cyrtlatherium–Simpsonodon (Forest Marble) and of Peraiocynodon–Docodon (Purbeck−Morrison) suggested by several authors is discussed. In conclusion, phyletic relationships between the known docodont genera are proposed, based on lower molars

Two possibly aqatic triconodont mammals from the Early Cretaceous of Marocco

Three mammalian molars from the Early Cretaceous of Morocco reveal the existence, at that time, of two new and peculiar species, one of them assigned to the Eotheria Triconodonta (uncertain family), Dyskritodon amazighi gen. et sp. n., the second only tentatively assigned to the Triconodonta, Ichthyoconodon jaworowskorum gen. et sp. n. The former is represented by a last lower molar which three main cusps (a, c, d) decrease regularly in size posteriorly while cusp b is very small and lingually situated, a unique condition for post-Liassic triconodonts. The second taxon (two specimens) is characterized by very narrow and trenchant teeth not intermeshing with adjacent ones, and carrying three subequal main cusps (b, a, c). Such dental morphology suggests that these mammals might have been semi-aquatic and piscivorous.W osadach wczesnej kredy (beriasu) Maroka znalezione zostały trzy zęby o piłkowanych płaskich koronach typowych dla rybożernych, wodnych kręgowców. Choć powierzchownie przypominają pokrojem zęby rekinów bądź pterozaurów, ich plan budowy da się porównać jedynie z zębami prymitywnych ssaków trikonodontów. Jeden z tych zębow, o coraz niższych kolejnych czterech wierzchołkach, należy prawdopodobnie do nowej rodziny trikonodontów i nazwany został Dyskritodon amazighi gen. et sp. n. Dwa inne zęby, o trzech spośród czterech wierzchołków zbliżonej wysokości, reprezentują jeszcze bardziej tajemniczy gatunek Ichthyoconodon jaworowskorum gen. et sp. n.Des sédiments littoraux du Crétacé inférieur du Haut-Atlas marocain, qui ont déjà livré de nombreux mammifères et autres vertébrés, ont été extraites trois dents trés particulières, attribuées à deux nouveaux taxons de mammifères Eotheria: Dyskritodon amazighi gen. et sp. n., ordre Triconodonta, famille indet., et Ichthyodonodon jaworowskorum gen. et sp. n., ordre ?Triconodonta, famille indet. Le premier est représenté par une dernière molaire inférieure, elle-même caractérisee par la petitesse du tubercule b, sa position cingulaire et un peu linguale et la décroissance régulière des tubercules a, c, d. Le second taxon est représenté par deux molaires isolées; trois tubercules (b, a, c) y sont subégaux comme chez les Triconodontidae, mais la dominance de c est un caractère tout à fait unique. En outre ces tubercules sont plus étroits et tranchants que chez tous les Triconodontes connus, et surtout il n'y a pas d'indentation antérieure témoignant de l'engrènement des dents adjacentes; il semblerait plutôt que ces dents se chevauchaient légèrement l'une l'autre. La morphologie dentaire de ces deux taxons, leur très bonne conservation en dépit de leur fragilité (tubercules élevés et minces), suggèrent que les animaux qui les portaient étaient semi-aquatiques et piscivores. II s'agit en tous cas de deux formes très spécialisées, et ce tout à fait independamment l'une de l'autre

Nouveaux taxons de mammiferes rhetiens

Dans cet article sont présentées quelques-unes des nouveautés découvertes dans le gisement français de Saint-Nicolas-de-Port. L’une des dents représente un nouvel Haramiyidé caractérisé essentiellement par la brièveté des rangées de tubercules et la présence ďun denticule antérieur à la rangée A. Deux dents „multituberculées” constituent la première indication de cet ordre dans le Rhétien. Enfin trois spécimens sont considérés comme représentant un nouveau genre et une nouvelle espèce de Morganucodonta, Brachyzostrodon coupatezl; ce taxon est comparé à tous les autres morganucodontes antérieurement décrits. Ce petit échantillonnage de la faune mammalienne du Rhétien inférieur parle en faveur ďune diversité des premiers mammifères bien supérieure à ce que l’on imaginait jusqu’ici.In this article are presented some of the new discoveries from the French Rhaetic locality of Saint-Nicolas de Port. One of the teeth represents a new haramiyid characterized essentially by the shortness of the rows of tubercules and the presence of a cusp anterior to the row A. Two „multituberculate” teeth constitute the first indication of this order in the Rhaetic. Finally, three specimens are considered as representing a new genus and species of Morganucodonta, Brachyzostrodon coupatezi; this taxon is compared to all the other known morganucodonts. This smali sample of the early Rhaetic mammalian fauna speaks in favor of a diversity within the first mammals well exceeding that imagined until now