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Two species of Hoploscaphites.
Full text link72 pages : illustrations (some color), map ; 26 cm.Two species of scaphitid ammonites (Ammonoidea: Ancyloceratina) from the Upper Cretaceous (lower Maastrichtian) of the Western Interior of North America are described. Hoploscaphites macer, n. sp., is medium size, with coarse ribs on the phragmocone, which become finer on the body chamber, and closely spaced ventrolateral tubercles. It occurs in the upper part of the Baculites baculus Zone and lower part of the overlying B. grandis Zone in the Pierre Shale in Montana, Wyoming, and Colorado, and in the Bearpaw Shale in Montana. Hoploscaphites criptonodosus (Riccardi, 1983) is larger and more coarsely ornamented, including one or two rows of lateral tubercles on the flanks of the phragmocone. It occurs in the upper part of the Baculites baculus Zone and overlying B. grandis Zone in the Pierre Shale in Montana, Wyoming, Colorado, and possibly South Dakota, and in the Bearpaw Shale in Montana and Saskatchewan, Canada. Both species form part of an evolving lineage of Hoploscaphites that first appears in the Western Interior of North America in the middle Campanian
Karyotypes of six species of colubrid snakes from the Western Hemisphere, and the 140-million-year-old ancestral karyotype of Serpentes. (American Museum novitates, no. 3926)
No full text13 pages : illustrations ; 26 cm.Karyotypes are described for six species of snakes from the Western Hemisphere, and comparisons are made with all species of snakes from around the world that have been karyotyped with modern methods. Although there is significant karyotypic variation in snakes, there is one basic karyotype that is shared by members of all families of snakes, representing widely divergent lineages, extending from today back through the evolutionary history of the Serpentes. Long-term survival of the ancestral snake karyotype may be a result of canalization, similar to some ancient chromosomes of turtles
New species of ponyfish.
Full text link14 pages : color illustrations ; 26 cm.A new species belonging to the leiognathid genus Photolateralis, collected from the coastal waters of Oman, is described herein. Photolateralis is unique among leiognathid genera in possessing a species-specific translucent midlateral flank stripe that may be comprised of either multiple independent translucent windows (P. stercorarius, P. moretoniensis, and the new species) or a continuous translucent lateral band (P. antongil). Photolateralis polyfenestrus, new species, is distinguished from congeners by the presence of a short, composite midlateral stripe comprised of three small, rounded translucent windows (vs. numerous windows in both P. stercorarius and P. moretoniensis, or a continuous translucent stripe in P. antongil), and that is confined to the midflank (vs. extending a majority of the length of the flank in congeners). The new species is further distinguished from both P. moretoniensis and P. antongil by a shallower body, and from both P. stercorarius and P. moretoniensis by a pigmentation pattern above the lateral midline comprised primarily of larger rounded blotches (vs. smaller sinuous lines and markings comprising a vermiculated pattern). Photolateralis polyfenestrus is characterized by a lower jaw that is deep and convex in lateral view (vs. mostly straight in congeners, excluding P. antongil), and that forms an angle of between 60°-70° to horizontal (vs. less than 45° in congeners, excluding P. antongil). The only other species of Photolateralis reported from the western Indian Ocean is P. antongil, to date only known from the coastal waters of Madagascar, whereas both P. stercorarius and P. moretoniensis have ranges restricted to the western Pacific and extending into the eastern Indian Ocean
First Tertiary fossils from Yukon.
Full text link28 pages : illustrations (some color), color map ; 26 cm.Despite over a century of prospecting and field research, fossil vertebrates are exceedingly rare in Paleogene and Neogene rocks in northern Canada's Yukon Territory. Here, we describe the first records of probable Neogene vertebrate fossils from the territory, including tooth fragments of a rhinocerotid, a partial calcaneum of an artiodactyl, shell fragments of the pond turtle Chrysemys s.l. and tortoise Hesperotestudo, and a fragment of a palatine of Esox (pike). Although the tooth fragments cannot be identified solely by traditional paleontological means, we use tooth enamel microstructure, and primarily the presence of vertical Hunter-Schreger bands, to refer them to the Rhinocerotidae. As the only known record of the Rhinocerotidae in North America's western Arctic, the tooth fragments from the Wolf Creek site support the hypothesis that the clade dispersed between Asia and North America across Beringia. The fossils are consistent with a Miocene age for the Wolf Creek site that is inferred from radiometric dates of the Miles Canyon basalt flows in the vicinity of the fossil locality. Further, the tortoise and pond turtle fossils indicate a mild climate in the Yukon at the time, consistent with the vegetation reconstructions of others that indicate a warmer, wetter world in the Miocene than today
Sauropod dinosaurs from northern Morrison Formation.
Full text link79 pages : illustrations (chiefly color), maps ; 26 cm.The Upper Jurassic Morrison Formation of the western United States preserves one of the best-known Mesozoic paleoecosystems worldwide. The formation crops out over an area from New Mexico and Oklahoma to Montana and Utah and encompasses a time span of approximately eight million years. Recent studies indicate a high diversity of gigantic, herbivorous sauropod dinosaurs, but the geographic and temporal distributions of species or even genera of these animals remain poorly understood. In particular, sauropod specimens from northern outcrops of the formation have rarely been studied in detail, and temporal relationships among sites are imprecise. Here, we reassess the taxonomic diversity of the sauropods from a historic Carnegie Museum locality in northern Wyoming. Previous referrals of material to the well-known diplodocid genera Apatosaurus and Diplodocus cannot be confidently confirmed; instead, all these specimens more likely represent elements from the recently recognized Galeamopus. Specimens previously assigned to Camarasaurus and Haplocanthosaurus could not be referred to these genera based on apomorphies, due to a lack of detailed knowledge concerning the genus- and species-level taxonomy of these sauropods. Our findings imply that many referrals of incomplete diplodocid skeletons to Apatosaurus and Diplodocus must be reassessed. These reassessments are particularly important with regard to specimens from northern localities of the Morrison Formation, as it is becoming increasingly evident that diplodocids from this area were distinct from better-known, more southerly taxa. This geographic segregation does not seem to apply to nondiplodocid sauropods; however, these taxa are also in need of systematic revision, which may reveal species-level patterns similar to those observed in Diplodocidae
The guardstone spiders of the Phrurotimpus palustris group (Araneae, Phrurolithidae). (American Museum novitates, no. 3944)
Full text link29 pages : color illustrations, maps ; 26 cm.The type species of Phrurotimpus, Herpyllus alarius Hentz, was based on a female from Alabama; because Hentz's type specimens were destroyed long ago, the identity of this species has been controversial for over a century. Examination of Hentz's original color paintings of his specimen indicates that earlier authors, such as Bishop and Crosby, and Chamberlin and Ivie, were correct in arguing that Emerton erred in assigning the name to a species common in the northeastern United States. Unfortunately, Kaston (who had access only to the published, black-and-white illustrations) subsequently sided with Emerton, and that misidentification has been followed in all more recent literature. Phrurotimpus palustris (Banks) and P. annulatus Chamberlin and Ivie are removed from the synonymy of P. alarius and considered valid. P. palustris refers to the common northeastern species, whereas P. annulatus refers to a sibling species apparently restricted to the southeastern United States; Hentz's P. alarius is a member of a different species group entirely. Four other species are assigned to the palustris group, which is known only from the eastern United States and Canada: P. umbratilis (Bishop and Crosby), P. wallacei (Gertsch, here transferred from Phrurolithus), and two new species: P. sorkini from Georgia and Florida and P. bernikerae from Florida
Small mammals of the Mayo River Basin, Peru.
Full text link67 pages : color illustrations, maps ; 26 cm.We present the results of an inventory of small mammals in the Mayo River basin, one of the least-studied regions of the Central Andes in Peru. We conducted inventories at three locations in May 2007. We collected 47 species of small mammals in the study area: five marsupials, 31 bats, and 11 rodents. A new species of Sturnira was encountered and is described. The new species, which was previously confused with S. lilium, occurs east of the Andes in Colombia, Ecuador, Peru, Bolivia, Venezuela, the Guianas, and Brazil, with an isolated record on the western slope of the Andes in Peru. Additionally, we report the presence of Anoura geoffroyi in Peru, Carollia sp. sensu Solari and Baker (2006) south of the Marañon River, and extend the elevational range of Neacomys spinosus and Oligoryzomys destructor. Our results highlight the need to conduct additional inventories to increase our understanding of the biodiversity of this rich and increasingly impacted region
Adzebills of New Zealand.
Full text link69 pages : illustrations (some color) ; 26 cm.Relationships among Neoaves, a group comprising approximately 95% of all extant birds, are difficult to resolve because of multiple short internodes presumably created by a rapid evolutionary radiation around the K/Pg boundary. This difficulty has plagued both morphological and molecular studies. Compared with molecular studies with extensive taxon and character sampling, morphological datasets have largely failed to provide insight into the phenotypic evolutionary transitions of the neoavian radiation. Extinct neoavian taxa remain an understudied but critical key to resolving relationships among these problematic stem lineages and understanding evolutionary changes in structure and function. Adzebills (Aptornis), some of the most phylogenetically controversial fossil neoavians, are extinct terrestrial birds endemic to New Zealand since at least the early Miocene. Past morphological studies have placed adzebills as a sister taxon to the flightless Kagu of New Caledonia (Rhynochetos jubatus) or to the land- and waterfowl group Galloanseres. Recent molecular studies reveal the Kagu and Sunbittern (Eurypyga helias) to be sister taxa, whereas adzebills have been postulated to be within Rallidae (rails, gallinules, and coots) or the sister taxon of Sarothruridae (flufftails) or Ralloidea (finfoots, flufftails, and rails). To better resolve the position of adzebills and begin constructing a fine-scale total evidence phylogenetic dataset for the base of Neoaves, we constructed a new and more comprehensive morphological dataset of 368 discrete osteological characters for 38 extant and two extinct taxa that includes extensive sampling of nearly all neoavian stem lineages. We then combined this dataset with 32 DNA sequences of the slowly evolving nuclear RAG1 and RAG2 genes. Morphological results place adzebills as the sister taxon of trumpeters (Psophia) within core Gruiformes and confirm strong support for a Kagu+Sunbittern sister group (99% bootstrap value). Results for analyses of the combined data were identical, and the adzebill+trumpeter clade was supported by a 99% Bayesian clade credibility value. Although the Kagu+Sunbittern sister group is consistent with recent molecular hypotheses, the adzebill+trumpeter group is novel