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Choristoderes are a group of extinct diapsid reptiles that once occupied the freshwater systems in the Northern Hemisphere from the Middle Jurassic through the Miocene. The Early Cretaceous monjurosuchid Philydrosaurus from western Liaoning, China, represents a transitional morphotype between a broad-snouted (crocodile-like) and a narrow-snouted (gavial-like) skull during the evolution of Choristodera. New specimens of the taxon from the Early Cretaceous Jiufotang Formation include an incomplete braincase and a nearly complete juvenile skeleton; the study of these specimens provides new information on the braincase and ontogenetic change of the skeleton of this transitional monjurosuchid. In the braincase floor, the foramen internus canalis caroticus externus opens in a groove lateral to the constricted lateral aspect of the parasphenoid, and ventral exposure of this foramen differs from Champsosaurus, in which parasphenoid/pterygoid fusion completely encloses the canal. On the occiput, the vagus nerve foramen penetrates the basioccipital, while the two foramina for the hypoglossal nerve open at the exoccipital/basioccipital suture. Comparative study of the new juvenile specimen with adult Philydrosaurus reveals previously unknown developmental changes of the cranial and postcranial skeleton of this monjurosuchid. Ontogenetically, Philydrosaurus underwent a dramatic change of skull proportions, including elongation of the antorbital and postorbital regions, and elongation of the jaws, with a great increase of the number of marginal teeth. The lower temporal fenestra is entirely closed in early ontogeny, as in large, fully-grown adults.

Although the known record of Mesozoic eutherian mammals has been significantly enriched in recent years, early eutherian evolution is still not well understood. Among the more controversial of Mesozoic eutherians is Paranyctoides Fox, which was described in 1979 from the Judithian Dinosaur Park Formation, Alberta, Canada. It is a rare taxon and therefore has been identified in only a few other North American Late Cretaceous local faunas since. Within the past decade, dental and gnathic remains discovered in Central Asia have also been referred to Paranyctoides, thereby expanding the geographic range of the genus substantially and making it the only Late Cretaceous eutherian ostensibly occurring in both continents. As a result of our detailed study of Paranyctoides, however, we find that the Central Asian species lack the diagnostic characters of Paranyctoides and must be referred to other taxa. We conclude that this genus was limited to North America, ranging from Aquilan to Lancian time, and accordingly we recognize as valid only the following species: Paranyctoides sternbergi (Judithian, Alberta), P. maleficus (Aquilan, Alberta), Paranyctoides Wahweap sp. A and sp. B (Judithian, Utah), Paranyctoides Kaiparowits sp. A and sp. B (Judithian, Utah). Another purported species of Paranyctoides, P. megakeros, from the Lancian of Wyoming, is a junior synonym of Alostera saskatchewanensis.

Pterosaurs were a unique clade of flying reptiles that were contemporaries of dinosaurs in Mesozoic ecosystems. The Pterodactyloidea as the most species-diverse group of pterosaurs dominated the sky during Cretaceous time, but earlier phases of their evolution remain poorly known. Here, we describe a 160 Ma filter-feeding pterosaur from western Liaoning, China, representing the geologically oldest record of the Ctenochasmatidae, a group of exclusive filter feeders characterized by an elongated snout and numerous fine teeth. The new pterosaur took the lead of a major ecological transition in pterosaur evolution from fish-catching to filter-feeding adaptation, prior to the Tithonian (145–152 Ma) diversification of the Ctenochasmatidae. Our research shows that the rise of ctenochasmatid pterosaurs was followed by the burst of eco-morphological divergence of other pterodactyloid clades, which involved a wide range of feeding adaptations that considerably altered the terrestrial ecosystems of the Cretaceous world.

Plesiadapidae are a family of Paleogene mammals thought to have phylogenetic affinities with modern Primates. We describe previously unpublished dentitions and the first skull and isolated petrosals of the plesiadapid Pronothodectes gaoi, collected from middle Tiffanian localities of the Paskapoo Formation in Alberta. Other species of Pronothodectes, traditionally considered the most basal members of the Plesiadapidae, occur at earlier, Torrejonian horizons in Montana, Wyoming, and Alberta. Classification of P. gaoi as a species of Pronothodectes has proved controversial; accordingly, we use the newly available samples and the more extensively preserved specimens to re-evaluate the generic affinities of this species. Included in our study are comparisons with craniodental material known for other plesiadapids and plesiadapiforms. Cladistic analysis of craniodental characters is used to assess the hypothesis that P. gaoi and other species in this genus are basal members of the Plesiadapidae. The new dental evidence confirms that P. gaoi lacks derived character states of other plesiadapids except for a variably present fissuring of the m3 hypoconulid. Moreover, several aspects of the cranium seem to be more primitive in P. gaoi (i.e., more like nonplesiadapid plesiadapiforms) than in later occurring plesiadapids, such as Plesiadapis tricuspidens and Plesiadapis cookei. Cladistic analysis of craniodental morphology supports a basal position of P. gaoi among species of Plesiadapidae, with the exception of other species of Pronothodectes. The basicranium of P. gaoi preserves a laterally placed bony canal for the internal carotid neurovascular system, suggesting that this was the ancestral condition for the family. Am J Phys Anthropol, 2012. © 2012 Wiley Periodicals, Inc.

Significant new material of the plesiadapiform Elphidotarsius russelli is described from Montana and Alberta. Previously the most poorly documented carpolestid, this species is now known from numerous isolated teeth and many jaw fragments. New material from the Crazy Mountains Basin, Montana substantially extends its known geographic range and shows that E. russelli is the most derived species of Elphidotarsius, with many features that foreshadow characteristics of Carpodaptes; consequently, emending the diagnosis of Elphidotarsius has been necessary. A phylogenetic analysis based on 73 characters scored for all species of Elphidotarsius, Pronothodectes, and Saxonella, as well as Purgatorius unio, Purgatorius janisae, Pandemonium dis, Chronolestes simul, and Carpodaptes hazelae, indicates that Elphidotarsius is a paraphyletic stem taxon at the base of Carpolestidae. Numerous crossing synapomorphies among these taxa show that a single anagenetic lineage can no longer represent the evolution of ear...

Schowalteria clemensi Fox and Naylor, from the latest Cretaceous lower Scollard Formation, Red Deer Valley, Alberta, is the only known Mesozoic member of the extinct mammalian order Taeniodonta. Schowalteria clemensi was originally classified in the derived family Stylinodontidae, but more recent studies employing computer-assisted phylogenetic and stratocladistic analyses of taeniodont interrelationships contend that S. clemensi is the basal taeniodont, whereas Onychodectes, long considered the basal taeniodont, is instead the sister group of stylinodontids alone. These studies, however, are deeply flawed, marred by selection of problematic outgroups, incorrect scoring of numerous character states and of the stratigraphic age of S. clemensi, omission of all stylinodontid-like characters of S. clemensi, and reliance on major, implausible reversals during early taeniodont history. The more recent of these analyses also examined the relationship of taeniodonts within Eutheria, but this data set incl...

New evidence from Elphidotarsius and Carpodaptes indicates that the primitive dental formula for Carpolestidae is I3/3, Cl/1, P4/3, M3/3, not I2/2, Cl/1, P3/3, M3/3, the formula long thought to be primitive for carpolestids and all other plesiadapiforms except Purgatorius; the revised formula differs from that of primitive Tertiary eutherians generally only in the loss of p1. Hence, if Carpolestidae and Plesiadapidae are sister groups, as has traditionally been believed, primitive carpolestids are more primitive than known plesiadapids in the number of incisors and retention of two upper teeth (C and P1) between I3 and P2. Nothing of the dentition or other known parts of the anatomy supports the recent suggestion that carpolestids are dermopterans.

The discovery of a skull and partial postcranial skeleton of Dicamptodon from northern Alberta is the earliest certain record of the subfamily Dicamptodontinae. The specimen comes from Late Paleocene lake sediments, which also contain the remains of fish and plants. The close resemblance of the specimen to larvae or neotenes of extant Dicamptodon shows that this family exhibits the common trend of extreme conservatism known from other salamanders. The specimen is found in association with floral assemblages, confirming Nussbaum's hypothesis of the origin of the genus in northwestern North America.

Salivary venoms are a rarity in mammals, found only in the duck-billed platypus, the Caribbean Solenodon, and a few shrews. Until now there were no known extinct mammals so equipped, but well preserved specimens of a small pantolestid insectivore have now been found with a venom delivery apparatus involving specialized teeth similar in function but structurally distinct from those of living venomous mammals. The specimens are about 60 million years old, from the late Palaeocene sediments in central Alberta that contain some exceptionally well preserved mammalian fossils. Numerous non-mammalian vertebrates have evolved lethal venoms to aid either in securing prey or as protection from predators, but modern mammals that use venoms in these ways are rare, including only the duck-billed platypus (Ornithorhynchus), the Caribbean Solenodon, and a few shrews (Soricidae) (Order Insectivora)1. Here we report evidence of a venom delivery apparatus in extinct mammals, documented by well-preserved specimens recovered from late Palaeocene rocks in Alberta, Canada2,3. Although classified within Eutheria, these mammals are phylogenetically remote from modern Insectivora4 and have evolved specialized teeth as salivary venom delivery systems (VDSs) that differ markedly from one another and from those of Solenodon and shrews. Our discoveries therefore show that mammals have been much more flexible in the evolution of VDSs than previously believed, contradicting currently held notions that modern insectivorans are representative of the supposedly limited role of salivary venoms in mammalian history. Evidently, small predatory eutherians have paralleled colubroid snakes5 in evolving salivary venoms and their delivery systems several times independently.

An enormous amount of data is available on the structure and function of the mammalian cochlea and mammalian hearing characteristics. Most of this knowledge is derived from studies of placental mammals, which is only one of the three groups of mammals that exist today. There are only a few studies on the ears and hearing characteristics of the other two living mammalian groups, the monotremes and the marsupials, and only recently have fossil specimens with sufficiently preserved inner ears become available that document important steps in evolution of the mammalian ear from the early Cretaceous up to the present. Mammals are an ancient group among terrestrial vertebrates that arose from mammal-like reptiles probably during the Triassic. The diagnostic features that clearly separate a mammal from its reptilian ancestors and other tetrapods include a property of the hearing apparatus, namely the presence of the three-ossicle middle ear. This key innovation appears to be one prerequisite for the capability of high-frequency hearing that is unique to mammals among tetrapods. The fossil record demonstrates that a middle ear with three ear ossicles precedes the evolution of an elongated and, in the more derived condition, coiled cochlea capable of hearing high frequencies well above 10kHz.

Symmetrodonts are Mesozoic mammals having lower molars with nearly symmetrical trigonids but lacking talonids. They appear to be stem members of the mammalian clade that led to extant tribosphenic mammals, but the fossil record of symmetrodonts is poor. Here we report a new genus and species of an acute-angled spalacotheriid symmetrodont, Heishanlestes changi, n.gen. and n.sp., represented by well-preserved lower jaws with teeth from the Early Cretaceous of northeastern China. The new mammal has four tightly spaced premolars and three morphological groups of lower molars, in which the first molar has an obtuse trigonid angle and the last two molars have a large neomorphic cusp in the center of the trigonid, a feature not seen in other mammals. Heishanlestes appears to be a specialized member of the spalacotheriid subfamily, Spalacolestinae, which is otherwise only known from North America. The animal probably used the premolars to crush its prey before shearing it with the molars.

A new genus and species of eutherian mammal having uncertain affinities is described from an incomplete lower jaw found in the late Paleocene Paskapoo Formation of central Alberta, Canada. The new mammal is characterized by a shallow dentary, no lower incisors, an enlarged lower canine, and a relatively long diastema between the canine and the first lower premolar, which is premolariform and two rooted. Closest resemblance of this new mammal is to epoicotheriid palaeanodonts (?Pholidota), although it differs in several, perhaps important, features from known epoicotheriids. If the Paskapoo mammal is a palaeanodont, it is the oldest known, constituting the most northerly record for the suborder, and the first from Canada.

Previously thought to be a salamander (Prosirenidae), Albanerpeton Estes and Hoffstetter (Jurassic to Miocene) possesses no known features otherwise restricted to salamanders. Its salamander-like features are only those held in common with small, limbed, non-saltatorial amphibians in general. In still other aspects (including feeding apparatus, dermal bones of the skull, and anterior cervical vertebrae), Albanerpeton appears unique. Already well isolated from salamanders, Albanerpeton seems no nearer phyletically to any other known amphibians, from Devonian to Recent. The relationships of Albanerpeton are most consistently indicated by classification in its own family (Albanerpetontidae, new) and order (Allocaudata, new), perhaps referrable to the Lissamphibia.

The Judithian (Late Cretaceous) stagodontid marsupial Eodelphis Matthew is known from two closely related species, E. cutleri and E. browni, which differ in size and proportions of P3 and robustness of the molars. P1 is shown to be two-rooted in both species and not only in E. cutleri, as previously believed. Known upper molars of Eodelphis lack a stylar cusp D, indicating that neither E. cutleri nor E. browni can be a part of the direct (species) ancestry of the later Cretaceous stagodontid Didelphodon. Evolution of the Stagodontidae probably included derivation of an E. cutleri-like radicle having robust premolars and molars from E. browni-like ancestors, present in North America by Aquilan time; development by the Edmontonian of specialized crushing premolars in primitive species of Didelphodon, descended from ancestors that were similar to E. cutleri in size but had a prominent stylar cusp D on the upper molars; and subsequent increase in size leading to Lancian D. vorax and D. padanicus. Contrary to recent speculation, the Stagodontidae have no special relationship to the Lower Cretaceous Pappotheriidae, which are Eutheria.

Eutherian mammals from the Upper Cretaceous Oldman Formation, Alberta, are described. These include the leptictid proteutherian Gypsonictops lewisi Sahni, which has five lower premolars and was probably the direct lineal ancestor of G. hypoconus Simpson of Lancian age; a new genus and species of primitive and generalized erinaceoid insectivore, which is the most adequate dental ancestor known for all Lipotyphla, Tupaiidae, Primates, Dermoptera, Chiroptera, and all of the ungulate mammals; and the first pre-Lancian occurrence in North America of the Family Palaeoryctidae.

The biology and ecology of Campoplex frustranae Cushman were studied in the laboratory and field in South Carolina from 1962 to 1964. This parasite was observed to oviposit in the 1st, 2nd, 3rd, and 4th instars of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock). All 1st- and 2nd-instar tip moth larvae died when stung by Campoplex. The highest buildup of Campoplex in the field occurred when most of the hosts were in the 3rd instar and at this time 10–15 Campoplex could be found flying around the top of a pine tree. This parasite has a rapid and erratic type of flight with the optimum flight occurring between 19 and 35°C. At temperatures above 32°C, Campoplex was observed to stop and rest more frequently with some rest periods up to 20 minutes. Campoplex was found to parasitize hosts in the upper ½ of the crown of pine trees, with parasitism greater in the upper ¼.

TEETH of North American mammals of early Campanian age were recently discovered in the Upper Milk River Formation, southern Alberta, Canada1, and now dental remains of Triconodonta2, Allotheria3, Metatheria, and Eutheria are known. The teeth are rare and occur with the fragmented skeletal parts of fishes, salamanders, turtles, champsosaurs, lizards, crocodiles, saurischians, and ornithischians, as in younger Cretaceous strata of the Western Interior4,5.

In studies of the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), larval head capsule sizes and other parameters were gathered to provide basic information to aid interpretation of phenomena associated with the destructive stages of this insect. Nash and Fox (1969) were able to separate tip moth stadia and generations, with the help of Dyar's (1890) principle modified according to Beck (1950), in control studies by use of a parasitic nematode. However, further evaluation was suggested as a result of variation encountered in lepidopterous larvae, especially in the larval studies of the elm spanworm, Ennomos subsignarius (Hubner), by Drooz (1965).

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