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JVP 26(3) September 2006—ABSTRACTS

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  • Neoceti Symposium, Saturday 8:45
  • acid-prepared osteolepiforms Medoevia and Gogonasus has offered strong support for

Jarvik’s interpretation, but Eusthenopteron itself has not been reexamined in detail. Uncertainty has persisted about the relationship between the large endoskeletal “fenestra endochoanalis” and the apparently much smaller choana, and about the occlusion of upper and lower jaw fangs relative to the choana.
A CT scan investigation of a large skull of Eusthenopteron, carried out in collaboration with University of Texas and Parc de Miguasha, offers an opportunity to image and digitally “dissect” a complete three-dimensional snout region. We find that a choana is indeed present, somewhat narrower but otherwise similar to that described by Jarvik. It does not receive the anterior coronoid fang, which bites mesial to the edge of the dermopalatine and is received by a pit in that bone. The fenestra endochoanalis is partly floored by the vomer and the dermopalatine, restricting the choana to the lateral part of the fenestra. The nasal cavity is proportionately much shorter than in Jarvik’s reconstruction, possibly because the latter was based on two specimens that were incorrectly aligned.

BODY SIZE AND CRYPTIC TROPHIC SEPARATION OF GENERALIZED PIERCE-FEEDING CETACEANS: THE ROLE OF FEEDING DIVERSITY DUR- ING THE RISE OF THE NEOCETI

ADAM, Peter, Univ. of California, Los Angeles, Los Angeles, CA; JETT, Kristin, Univ. of California, Davis, Davis, CA; OLSON, Joshua, Univ. of California, Los Angeles, Los Angeles, CA Marine mammals with homodont dentition and relatively little specialization of the feeding apparatus are often categorized as generalist eaters of squid and fish. However, analyses of many modern ecosystems reveal the importance of body size in determining trophic partitioning and diversity among predators. We established relationships between body sizes of extant cetaceans and their prey in order to infer prey size and potential trophic separation of generalized fossil cetaceans. Methods for predicting body size of fossil taxa from three occipital measures (bicondylar breadth; foramen magnum and occipital condyle areas) were also developed using allometric models determined from measurements made on >2500 skulls representing all extant species. Models for body size prediction were confirmed for numerous fossil taxa with well-preserved axial postcrania. Enhanced by inclusion of additional parameters describing the feeding apparatus (tooth density; tooth row length and position; rostrum length/breadth; tooth cross-sectional area and eccentricity as measured at the enamel-dentine juncture), body size was found to be a useful predictor of prey size in generalized cetaceans. We used body size and these other parameters to infer trophic roles for a large number of Oligocene and Miocene cetaceans with unspecialized feeding anatomy. Overall, trophic diversity of generalized cetaceans was low in the Oligocene, but increased dramatically in the Middle-Late Miocene and later. This transition marks the extinction of squalodontids and other pre-neocete lineages and rise and diversification of the Neoceti, and superficially suggests that the Neoceti competitively displaced its ancestors. However, major changes in oceanographic conditions (including latitudinal stratification of oceans and increased coastal upwelling) and changes in the prey base utilized by cetaceans were also occurring during this time, rendering simple competitive scenarios for this transition untenable. We suggest that numerous factors played a role in the rise and diversification of the Neoceti, but their adaptability to changing environmental conditions was a major factor accounting for their success.
Poster Session III

THE DICROSTONYX PARADOX, NEW EVIDENCE FROM A 40,000 YBP MICRO- FAUNA, JAGUAR CAVE EASTERN IDAHO

AKERSTEN, William, Idaho State Univ., Pocatello, ID All modern Dicrostonyx are well adapted to arctic tundra conditions; consequently, Pleistocene occurrences have been viewed as definitive evidence of past tundra conditions and disharmonious associations. A few have suggested that the evidence is more compatible with a change in the ecological requirements of Dicrostonyx. A very fossiliferous 160 cm section recently excavated in 20 cm increments from Jaguar Cave at the base of the Beaverhead Mountains dates from 39,120 BP to >48,400 BP. The matrix is comprised of small, interlocking siliceous limestone fragments weakly cemented by loess, very difficult to excavate, which would have all but eliminated mixing of levels. Small numbers of Dicrostonyx groenlandicus occur through most or all of the section (not all levels have yet been completely processed and studied) in disharmonious association with Lemmiscus, other small mammals, and as yet unidentified snakes and lizards. While the mammal association can readily be explained an example of a disharmonious association, the association of snakes and lizards with a supposed tundra form is extremely difficult to explain. The key taxon appears to be Dicrostonyx; its adaptations may be more related to deep snow, not necessarily to tundra conditions. I suggest that its present distribution, allopatric (except for a modest overlap) with the widespread and very adaptable Microtus pennsylvanicus, has resulted from its having been gradually outcompeted by the latter over much of its original range, remaining only in its present tundra refugia. One explanation for the co-occurrence of Dicrostonyx and small reptiles at Jaguar Cave 40,000 years ago is that the winters had fairly deep snows which favored the adaptations of Dicrostonyx, but the summers were relatively warm and long enough for small reptiles to reproduce and obtain adequate food for winter hibernation. My interpretation is that North American Dicrostonyx is an indicator of substantial snow depth but may or may not be an indicator for tundra conditions.
Poster Session III

DYNAMICS OF ENVIRONMENTAL CHANGES DURING THE LATE PLEIS- TOCENE IN THE ALTAI MOUNTAINS (RUSSIA, WESTERN SIBERIA) BASED ON MAMMAL AND MOLLUSK DATA FROM PALEOLITHIC ARCHEOLOGI- CAL SITES

AGADJANIAN, Alexandre, Paleontological Institute RAS, Moscow, Russia; KON- DRASHOV, Peter, Northwest Missouri State Univ., Maryville, MO Faunal studies aimed for the reconstruction of the paleoenviroment of the late Pleistocene and its dynamics during the time of prehistoric man were conducted through the analysis of extant biota and through the study of the fossil biota including mollusks, birds, and mammals from the deposits of the Paleolithic archeological sites. Nine major extant plant associations, each with its specific mammal and mollusk fauna, were identified. The most typical existing association in the northwestern Altai Mountains is the taiga with scattered alpine and steppe elements. Extinct communities of mammals, birds and mollusks in the Altai Mountains went through significant faunal changes during the late PleistoceneHolocene. Most of the biotic changes were caused by climate, but some could have resulted from the influence of prehistoric man. Climatic changes caused abrupt decrease of the nival and steppe elements in the biota and increase in the number of taiga species. Despite these changes many species survived the Pleistocene/Holocene transition. Presence of Siberian species in both extinct and extant Altai faunas indicates that changes in the ecological composition of the paleocommunities occurred in otherwise zoogeographically stable environment. Changes in the composition of the biota of the studied region occurred through the “recruitment” of taxa from other regions of Altai Mountains and adjacent territories. Using a combined approach and including such groups as mollusks in the analysis allowed us to confirm and more precisely describe the dynamics of the paleoenvironmental changes in the late Pleistocene and Holocene. Number of bones of small and large mammals as well as the number of Paleolithic artifacts showed that prehistoric man had an important influence on the paleoenviroment of the ecosystems of the Altai Mountains. Previously conducted studies show that prehistoric man occupied the niche of a “large carnivore”. It was documented that prehistoric man were eliminating part of the ungulate population and were competing with such carnivores as the cave bear and cave hyena.
Marine Reptiles Symposium, Wednesday 2:00

AN UPDATE ON NEW MARINE REPTILES FROM THE TROPIC SHALE OF SOUTHERN UTAH

ALBRIGHT, L., Univ. of North Florida, Jacksonville, FL; GILLETTE, David, Museum of Northern Arizona, Flagstaff, AZ; TITUS, Alan, Grand Staircase-Escalante National Monument, Kanab, UT Fieldwork conducted in the Tropic Shale of southern Utah, ongoing since 2000, has resulted in the recovery of several specimens of short-necked plesiosaurs representing both the Polycotylidae and the Pliosauridae. Although these specimens have been reported in previous abstracts, completion of our studies has resulted in revised conclusions. Of three different polycotylids recovered, it has been determined that two represent new taxa. In addition to the known Trinacromerum bentonianum, one of the new taxa appears to share a sister taxon relationship with the late Santonian/early Campanian Polycotylus latipinnus. The second new taxon, together with new unnamed taxa from the late Cenomanian of South Dakota and Japan, represents a new clade of polycotylids based primarily on the distinctive morphology of certain paddle elements. Representing the Pliosauridae are two new specimens of Brachauchenius lucasi, both of which include skull material and one of which includes pectoral and pelvic elements previously unknown for this taxon. Although the Late Cretaceous Cenomanian/Turonian Stage boundary falls within the lower part of this unit, all but one of the specimens was found in lower Turonian strata based on molluscan assemblages found in direct association with the skeletal material. The Turonian plesiosaur fauna of the Tropic Shale, and consequently the large vertebrate fauna of the Cretaceous Western Interior Seaway, is considerably more diverse than previously realized. There is no indication that this fauna suffered any negative consequences as a result of global scale oceanographic events, including marine extinctions, that transpired during late Cenomanian-early Turonian time.
Saturday 9:15

CT SCANNING THE NOSE OF EUSTHENOPTERON

AHLBERG, Per, Uppsala Univ., Uppsala, Sweden Historically, the debate about the origin of the tetrapod choana has focused substantially on a single taxon, the osteolepiform lobe-finned fish Eusthenopteron foordi from the Late Devonian of Miguasha, Quebec. A three-dimensional skull of this fish was described exhaustively by Jarvik from a grinding series, arguably making it the best understood of all Devonian vertebrates. Nevertheless, Jarvik’s description of a tetrapod-like choana in Eusthenopteron was challenged head-on in 1981 by Rosen et al., who claimed that Jarvik had exaggerated the size of the supposed internal nostril, and that this opening was really a fang pit receiving the tip of the anterior coronoid fang. More recently, evidence from the
Romer Prize Session, Thursday 8:00

A NOVEL APPROACH TO RESOLVE BASAL CROCODYLOMORPH SYSTEM- ATICS

ALLEN, David, DeKalb, IL Modern crocodilians are crurotarsan archosaurs called crocodylomorphs. The basal-most genera belonged to subgroups Sphenosuchia and Protosuchia. In contrast to extant semi-

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JVP 26(3) September 2006—ABSTRACTS

aquatic sprawling crocodilians, sphenosuchians and protosuchians lived mainly in terrestrial settings and had more erect limbs. Over the past twenty years researchers have attempted to resolve phylogenetic relationships within and between these groups. Many analyses suffered from poor preservation of specimens and a bias towards the study of cranial compared to postcranial features. The monophyly of Sphenosuchia and Protosuchia is questioned because of weak support. New character-taxon matrices are often produced by adding a small number of novel characters to portions of pre-existing datasets, giving new and larger matrices. This study investigates the systematic relationships between Sphenosuchia and Protosuchia and within each of these groups. To achieve this goal, a supermatrix has been compiled containing sphenosuchian and protosuchian genera with both novel and published characters. One of the limitations of a supermatrix approach is the great quantity of missing data encountered as a result of inapplicable characters and incomplete specimens. To avoid this, a novel analytical method named the supermatrix-supertree method, is introduced. In this approach a supermatrix is subdivided into a series of submatrices based on which body region each character applies to. Genera only represented by skulls can still be included without requiring lots of missing data. Each submatrix is treated as a separate analysis and resultant most parsimonious trees form the basis of a supertree analysis to combine the partially overlapping trees into a single phylogeny. This novel approach emphasizes the positive aspects of fossil specimens by focusing on preserved bones, thereby reducing the negative effects of missing data and avoiding the exclusion of poorly represented genera. My analyses show that suites of regional cranial and postcranial characters are not bound to agree regarding the monophyly of these groups. However, any conflicting phylogenetic signals are reconciled by the supertree building process.
Poster Session II

NEWLY DISCOVERED PARTIAL CRANIUM OF ACRITOPARAMYS FRANCESCI (RODENTIA: ISCHYROMYIDAE) FROM THE BIGHORN BASIN, WYOMING SUPPORTS A CHANGE IN CLASSIFICATION TO THE SUBFAMILY PARAMYI- NAE

ANDERSON, Deborah, St. Norbert College, De Pere, WI Acritoparamys francesci is one of the earliest known members of the family Ischyromyidae, its fossil record beginning in the Early Eocene (55.5 MA). Originally classified in the subfamily Paramyinae, the genus was moved to the Reithroparamyinae based primarily on characteristics of the molar crown pattern and anterior position (level with middle of P4) of the posterior aspect of the anterior root of the zygoma. Recent discovery of a partial cranium of Acritoparamys francesci from the Bighorn Basin, Wyoming is the basis for a more complete analysis of the evolutionary relationships and taxonomic status of the genus. The specimen includes a complete set of left molars (dP3-M3) associated with the partial cranium, and the right P4 and M1 on a maxillary fragment, as well as two nearly complete mandibles with all molars in situ. This is the first reported M3 known for the species. Qualitative features of the cranium were compared to other skulls known for the subfamily Reithroparamyinae and Paramyinae. The M3 was described in detail; other molars were similar to those found in previously described specimens. Cranial features found to be distinct from other members of the subfamily Reithroparamyinae include the curved maxillapremaxilla, large angle of the anterior face of the zygoma, a rounded piece of maxilla separating premaxilla from the orbit, posterior aspect of orbit broad and rounded instead of angular, relatively large infraorbital foramen, and posterior margin of anterior part of the zygomatic arch in line with anteroloph of M1. In each case, the skull more closely resembles those known for the Subfamily Paramyinae, supporting reclassification to this taxon.
Saturday 2:00

A REVISED QUANTITATIVE TIME SCALE FOR NORTH AMERICAN CRETA- CEOUS AND CENOZOIC VERTEBRATES

Saturday 11:30
ALROY, John, Univ. of California, Santa Barbara, CA

ON THE SKULL OF CACOPS ASPIDEPHORUS WILLISTON (TETRAPODA; TEMNOSPONDYLI; DISSOROPHIDAE) FROM THE LOWER PERMIAN OF TEXAS

Many European mammal workers have adopted quantitative biochronological methods like appearance event ordination (AEO), which also have been widely used by invertebrate paleontologists and micropaleontologists for more than 40 years. Most North American mammal workers still use a time scale whose definitions, boundary ages, and faunal correlations are set by committee. A 2004 book on North American mammals with 34 authors devotes 20 pages to semantics and two sentences to a dismissal of quantitative methods. It prefers to equate age and subage boundaries with first appearances of immigrant genera (IFADs), even though generic appearances are unstable and diachronous, as shown in 1998. An event sequence generated by AEO using the latest species-level Cretaceous and Cenozoic North American Paleobiology Database data is highly accurate: the rank-order correlation (ρ) between concurrent range zones (CRZs) of collections and 73 Ar-Ar dates tied to them is 0.993. Taxonomy doesn’t matter. Accuracy is just as high if an event sequence is computed using the original published identifications and ignoring reidentifications and synonymies (ρ = 0.995). Nearly half of collections don’t include any immigrant genera, so in principle they can’t be correlated using IFADs. Subages can be estimated for the others using the IFAD of the last-appearing genus each includes. After numbering the subages in order, these assignments have unacceptable correlations with the dates (n = 47, ρ = 0.960; ρ = 0.988 for CRZs compared with these dates only). Thus, the committees seem to have used diverse criteria instead of the IFAD definitions. Simply matching their age assignments with the dates yields a correlation similar to that seen for the AEO estimates (ρ = 0.994), despite the fact that the dates themselves were used to determine the assignments. So, assignments for all other collections can only be more discordant. Thus, the mammal age system is highly inaccurate if its definitions are taken seriously, and still inaccurate if they are ignored. Current numerical age estimates based on quantitative biochronology are available on the Paleobiology Database web site.
ANDERSON, Jason, Univ. of Calgary, Calgary, AB, Canada One of the most frequently depicted amphibians from the Early Permian, the armored temnospondyl Cacops aspidephorus, is also among the most poorly known dissorophids in terms of cranial anatomy. Because the matrix tightly encrusts the bone, it is difficult to determine where matrix ends and bone begins. The type series was prepared in such a manner as to obliterate the external surface of the bone so that, although complete skulls of Cacops are known, no sutures have been described.
A partially prepared specimen on display at the University of Michigan Exhibits
Museum was investigated as a part of my revision of dissorophoid temnospondyls. After cleaning it was discovered to have a full compliment of sutures on the lower jaw, which prompted my present exploration of all unprepared cranial material from the Cacops Bone Bed held at the Field Museum of Natural History. This new material was supplemented by reexamination of the type series.
Sutures demarking all ossifications of the lower jaw save the articular can be made out with varying degrees of clarity. Sutures on the lateral skull, skull roof, and palate are also distinguishable. Most important features to note in the skull proper include the presence of alary processes on the premaxilla, a very thin maxilla, and an LEP that might have been prevented from participating in the ventral orbital margin. Rostrally the lower jaw of Cacops is very narrow and only the dentary can be seen except for a small exposure of the presplenial. The presplenial comes to a point at the symphysis but does not seem to contribute to it. An adsymphysial ossification, the first described from a dissorophoid, bearing a fang and replacement pit pair forms the lingual half of the symphysis in a pattern similar to that in the colosteid Greererpeton burkemorani. These features allow Cacops to be coded in a matrix of lower tetrapod jaw characters, which will be explored in detail. With the recent description of an adsymphyseal in an amphibamid temnospondyl, it raises the possibility that the adsymphyseal of lower tetrapods may be homologous to the mentomeckelian ossification in modern amphibians. This character will be discussed at length.
Poster Session III

ON THE OCURRENCE OF NOTELOPS IN TLAYÚA QUARRY, TEPEXI DE RODRÍGUEZ, PUEBLA, MÉXICO

ALVARADO-ORTEGA, Jesús; MAYRINCK, Diogo de; BRITO, Paulo, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
Poster Session I

LOCOMOTOR STRATEGY AND MASS PREDICTION FOR THE NOTOUNGU- LATE PROTYPOTHERIUM (EARLY MIOCENE, SANTA CRUZ, ARGENTINA)

ANDERSON, Leah, CROFT, Darin, Case Western Reserve Univ., Cleveland, OH
Mammal fossils are abundant, diverse, and well preserved in the early Miocene Santa
Cruz Fauna of southern Argentina. Some of the most common remains are of notoungulates, the most speciose group of endemic South American ungulates. Despite the availability of excellent specimens, few studies have investigated notoungulate paleobiology. This partly stems from the lack of living descendents which presents challenges for reconstructing attributes such as body mass and locomotor strategy. We here present results of a study that uses a variety of extant mammals to infer these attributes for one Santa Cruz notoungulate, Protypotherium (Interatheriidae: Interatheriinae).
Postcranial measurements were taken from 45 species of modern rodents, lagomorphs, and ungulates of known body mass (< 10 kg) and locomotor habit (fossorial, occasionally fossorial, generalized, saltatory, cursorial, or arboreal). Some measurements were expressed as ratios to form ten indices related to limb function (e.g. humerus robustness index). Body mass of Protypotherium was inferred using 14 postcranial regression equa-
Tlayúa Quarry is the most important fossil fish locality in México. A rich and diverse fish assemblage has been recovered from its limestone strata deposited under marine and freshwater influences. The occurrence of Notelops in this Early Cretaceous Mexican locality has been only vaguely reported. A review of some of these specimens confirms the original generic assignation and reveals that they represent a new species of Notelops, which until now has been formally recognized as a monotypic genus. The presence of a suite of characters such as two rows of teeth in the lower and upper jaws, dorsal fin located slightly behind the middle body, first uroneural reaching the second preural centrum, and the presence of about 50 to 55 preural centra supports this preliminary proposal. The occurrence of this new species increases the geographical range of Notelops from the Albian deposits of Santana Formation, Northeastern Brazil, to the Albian deposits of Tlayúa Quarry, Puebla, Central Mexico. A morphological review of Notelops is undertaken to attribute its phylogenetic position with respect to all known Pachyrhizodontoidei.

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    TH FRIENDS OF THE PLEISTOCENE, ROCKY MOUNTAIN-CELL, 45 FIELD CONFERENCE PLIO-PLEISTOCENE STRATIGRAPHY AND GEOMORPHOLOGY OF THE CENTRAL PART OF THE ALBUQUERQUE BASIN OCTOBER 12-14, 2001 SEAN D. CONNELL New Mexico Bureau of Geology and Mineral Resources-Albuquerque Office, New Mexico Institute of Mining and Technology, 2808 Central Ave. SE, Albuquerque, New Mexico 87106 DAVID W. LOVE New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801 JOHN D. SORRELL Tribal Hydrologist, Pueblo of Isleta, P.O. Box 1270, Isleta, NM 87022 J. BRUCE J. HARRISON Dept. of Earth and Environmental Sciences, New Mexico Institute of Mining and Technology 801 Leroy Place, Socorro, NM 87801 Open-File Report 454C and D Initial Release: October 11, 2001 New Mexico Bureau of Geology and Mineral Resources New Mexico Institute of Mining and Technology 801 Leroy Place, Socorro, NM 87801 NMBGMR OFR454 C & D INTRODUCTION This field-guide accompanies the 45th annual Rocky Mountain Cell of the Friends of the Pleistocene (FOP), held at Isleta Lakes, New Mexico. The Friends of the Pleistocene is an informal gathering of Quaternary geologists, geomorphologists, and pedologists who meet annually in the field. The field guide has been separated into two parts. Part C (open-file report 454C) contains the three-days of road logs and stop descriptions. Part D (open-file report 454D) contains a collection of mini-papers relevant to field-trip stops. This field guide is a companion to open-file report 454A and 454B, which accompanied a field trip for the annual meeting of the Rocky Mountain/South Central Section of the Geological Society of America, held in Albuquerque in late April.
  • Ambush Predator’ Guild – Are There Developmental Rules Underlying Body Shape Evolution in Ray-Finned Fishes? Erin E Maxwell1* and Laura AB Wilson2

    Ambush Predator’ Guild – Are There Developmental Rules Underlying Body Shape Evolution in Ray-Finned Fishes? Erin E Maxwell1* and Laura AB Wilson2

    Maxwell and Wilson BMC Evolutionary Biology 2013, 13:265 http://www.biomedcentral.com/1471-2148/13/265 RESEARCH ARTICLE Open Access Regionalization of the axial skeleton in the ‘ambush predator’ guild – are there developmental rules underlying body shape evolution in ray-finned fishes? Erin E Maxwell1* and Laura AB Wilson2 Abstract Background: A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The axial skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the axial skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts. Results: We report that in five of the clades surveyed, Lepisosteidae, Esocidae, Belonidae, Sphyraenidae and Fistulariidae, vertebrae are added preferentially to the abdominal region. In Lepisosteidae, Esocidae, and Belonidae, increasing abdominal vertebral count was also significantly related to increasing fineness ratio, a measure of elongation. Two clades did not preferentially add abdominal vertebrae: Saurichthyidae and Aulostomidae. Both of these groups show the development of a novel caudal region anterior to the insertion of the anal fin, morphologically differentiated from more posterior caudal vertebrae.
  • Osteichthyes, Actinopterygii) from the Early Triassic of Northwestern Madagascar

    Osteichthyes, Actinopterygii) from the Early Triassic of Northwestern Madagascar

    Rivista Italiana di Paleontologia e Stratigrafia (Research in Paleontology and Stratigraphy) vol. 123(2): 219-242. July 2017 REDESCRIPTION OF ‘PERLEIDUS’ (OSTEICHTHYES, ACTINOPTERYGII) FROM THE EARLY TRIASSIC OF NORTHWESTERN MADAGASCAR GIUSEPPE MARRAMÀ1*, CRISTINA LOMBARDO2, ANDREA TINTORI2 & GIORGIO CARNEVALE3 1*Corresponding author. Department of Paleontology, University of Vienna, Geozentrum, Althanstrasse 14, 1090 Vienna, Austria. E-mail: [email protected] 2Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Mangiagalli 34, I-20133 Milano, Italy. E-mail: cristina.lombardo@ unimi.it; [email protected] 3Dipartimento di Scienze della Terra, Università degli Studi di Torino, Via Valperga Caluso 35, I-10125 Torino, Italy. E-mail: giorgio.carnevale@ unito.it To cite this article: Marramà G., Lombardo C., Tintori A. & Carnevale G. (2017) - Redescription of ‘Perleidus’ (Osteichthyes, Actinopterygii) from the Early Triassic of northwestern Madagascar . Riv. It. Paleontol. Strat., 123(2): 219-242. Keywords: Teffichthys gen. n.; TEFF; Ankitokazo basin; geometric morphometrics; intraspecific variation; basal actinopterygians. Abstract. The revision of the material from the Lower Triassic fossil-bearing-nodule levels from northwe- stern Madagascar supports the assumption that the genus Perleidus De Alessandri, 1910 is not present in the Early Triassic. In the past, the presence of this genus has been reported in the Early Triassic of Angola, Canada, China, Greenland, Madagascar and Spitsbergen. More recently, it has been pointed out that these taxa may not be ascri- bed to Perleidus owing to several anatomical differences. The morphometric, meristic and morphological analyses revealed a remarkable ontogenetic and individual intraspecific variation among dozens of specimens from the lower Triassic of Ankitokazo basin, northwestern Madagascar and allowed to consider the two Malagasyan species P.
  • How to Cite Complete Issue More Information About This Article

    How to Cite Complete Issue More Information About This Article

    Boletín de la Sociedad Geológica Mexicana ISSN: 1405-3322 Sociedad Geológica Mexicana, A.C. Hernández Cisneros, Atzcalli Ehécatl; González Barba, Gerardo; Fordyce, Robert Ewan Oligocene cetaceans from Baja California Sur, Mexico Boletín de la Sociedad Geológica Mexicana, vol. 69, no. 1, January-April, 2017, pp. 149-173 Sociedad Geológica Mexicana, A.C. Available in: http://www.redalyc.org/articulo.oa?id=94350664007 How to cite Complete issue Scientific Information System Redalyc More information about this article Network of Scientific Journals from Latin America and the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Project academic non-profit, developed under the open access initiative Boletín de la Sociedad Geológica Mexicana / 2017 / 149 Oligocene cetaceans from Baja California Sur, Mexico Atzcalli Ehécatl Hernández Cisneros, Gerardo González Barba, Robert Ewan Fordyce ABSTRACT Atzcalli Ehecatl Hernández Cisneros ABSTRACT RESUMEN [email protected] Museo de Historia Natural de la Universidad Autónoma de Baja California Sur, Univer- Baja California Sur has an import- Baja California Sur tiene un importante re- sidad Autónoma de Baja California Sur, ant Cenozoic marine fossil record gistro de fósiles marinos del Cenozoico que Carretera al Sur Km 5.5, Apartado Postal which includes diverse but poorly incluye los restos poco conocidos de cetáceos 19-B, C.P. 23080, La Paz, Baja California Sur, México. known Oligocene cetaceans from del Oligoceno de México. En este estudio Instituto Politécnico Nacional, Centro Inter- Mexico. Here we review the cetacean ofrecemos más detalles sobre estos fósiles de disciplinario de Ciencias Marinas (CICMAR), fossil record including new observa- cetáceos, incluyendo nuevas observaciones Av. Instituto Politécnico Nacional s/n, Col.
  • The First Crocodyliforms Remains from La Parrita Locality, Cerro Del Pueblo

    The First Crocodyliforms Remains from La Parrita Locality, Cerro Del Pueblo

    Boletín de la Sociedad Geológica Mexicana / 2019 / 727 The first crocodyliforms remains from La Parrita locality, Cerro del Pueblo Formation (Campanian), Coahuila, Mexico Héctor E. Rivera-Sylva, Gerardo Carbot-Chanona, Rafael Vivas-González, Lizbeth Nava-Rodríguez, Fernando Cabral-Valdéz ABSTRACT Héctor E. Rivera-Sylva ABSTRACT RESUMEN Fernando Cabral-Valdéz Departamento de Paleontología, Museo del Desierto, Carlos Abedrop Dávila 3745, 25022, The record of land tetrapods of El registro de tetrápodos terrestres en la Saltillo, Coahuila, Mexico. the Cerro del Pueblo Formation Formación Cerro del Pueblo (Cretácico (Late Cretaceous, Campanian), in Gerardo Carbot-Chanona tardío, Campaniano) en Coahuila, incluye Coahuila, includes turtles, pterosaurs, [email protected] tortugas, pterosaurios, dinosaurios y Museo de Paleontología “Eliseo Palacios Aguil- dinosaurs, and crocodyliforms. This era”, Secretaría de Medio Ambiente e Historia last group is represented only by crocodyliformes. Este último grupo está Natural. Calzada de los hombres ilustres s/n, representado por goniofólididos, eusuquios 29000, Tuxtla Gutiérrez, Chiapas, Mexico. goniopholidids, indeterminate eusu- chians, and Brachychampsa montana. In indeterminados y Brachychampsa montana. Rafael Vivas-González this work we report the first crocodyli- En este trabajo se reportan los primeros Villa Nápoles 6506, Colonia Mirador de las Mitras, 64348, Monterrey, N. L., Mexico. form remains from La Parrita locality, restos de crocodyliformes de la localidad Cerro del Pueblo Formation, based La Parrita, Formación Cerro del Pueblo, Lizbeth Nava-Rodríguez on one isolated tooth, vertebrae, and con base en un diente aislado, vértebras y Facultad de Ingeniería, Universidad Autóno- osteoderms. The association of croc- ma de San Luis Potosí, Dr. Manuel Nava 8, osteodermos. La asociación de crocodyli- Zona Universitaria Poniente, San Luis Potosi, odyliforms, turtles, dinosaurs, and formes, tortugas, dinosaurios y oogonias S.L.P., Mexico.
  • An Early Miocene Dome-Skulled Chalicothere

    An Early Miocene Dome-Skulled Chalicothere

    PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024 Number 3486, 45 pp., 26 ®gures, 8 tables October 27, 2005 An Early Miocene Dome-Skulled Chalicothere from the ``Arikaree'' Conglomerates of Darton: Calibrating the Ages of High Plains Paleovalleys Against Rocky Mountain Tectonism ROBERT M. HUNT, JR.1 CONTENTS Abstract ....................................................................... 2 Introduction .................................................................... 2 Geologic Setting ................................................................ 3 Systematic Paleontology ........................................................ 12 Age of the Dome-Skulled Chalicothere ........................................... 28 The ``Arikaree'' Conglomerates of N.H. Darton ................................... 32 Post-Laramide Evolution of the Rocky Mountains ................................. 39 Acknowledgments ............................................................. 42 References .................................................................... 42 1 Department of Geosciences, W436 Nebraska Hall, University of Nebraska, Lincoln, NE 68588-0549 ([email protected]). Copyright q American Museum of Natural History 2005 ISSN 0003-0082 2 AMERICAN MUSEUM NOVITATES NO. 3486 ABSTRACT Fragmentary skeletal remains discovered in 1979 in southeastern Wyoming, associated with a mammalian fauna of early Hemingfordian age (;18.2 to 18.8 Ma), represent the oldest known occurrence of dome-skulled chalicotheres
  • Pliocene and Early Pleistocene) Faunas from New Mexico

    Pliocene and Early Pleistocene) Faunas from New Mexico

    Chapter 12 Mammalian Biochronology of Blancan and Irvingtonian (Pliocene and Early Pleistocene) Faunas from New Mexico GARY S. MORGAN1 AND SPENCER G. LUCAS2 ABSTRACT Signi®cant mammalian faunas of Pliocene (Blancan) and early Pleistocene (early and medial Irvingtonian) age are known from the Rio Grande and Gila River valleys of New Mexico. Fossiliferous exposures of the Santa Fe Group in the Rio Grande Valley, extending from the EspanÄola basin in northern New Mexico to the Mesilla basin in southernmost New Mexico, have produced 21 Blancan and 6 Irvingtonian vertebrate assemblages; three Blancan faunas occur in the Gila River Valley in the Mangas and Duncan basins in southwestern New Mexico. More than half of these faunas contain ®ve or more species of mammals, and many have associated radioisotopic dates and/or magnetostratigraphy, allowing for correlation with the North American land-mammal biochronology. Two diverse early Blancan (4.5±3.6 Ma) faunas are known from New Mexico, the Truth or Consequences Local Fauna (LF) from the Palomas basin and the Buckhorn LF from the Mangas basin. The former contains ®ve species of mammals indicative of the early Blancan: Borophagus cf. B. hilli, Notolagus lepusculus, Neo- toma quadriplicata, Jacobsomys sp., and Odocoileus brachyodontus. Associated magnetostra- tigraphic data suggest correlation with either the Nunivak or Cochiti Subchrons of the Gilbert Chron (4.6±4.2 Ma), which is in accord with the early Blancan age indicated by the mam- malian biochronology. The Truth or Consequences LF is similar in age to the Verde LF from Arizona, and slightly older than the Rexroad 3 and Fox Canyon faunas from Kansas.