scholarly journals Redescription ofCalyptosuchus(Stagonolepis)wellesi(Archosauria: Pseudosuchia: Aetosauria) from the Late Triassic of the Southwestern United States with a discussion of genera in vertebrate paleontology

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4291 ◽  
Author(s):  
William G. Parker
Keyword(s):  
United States ◽  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Phylogenetic Analyses ◽  
Western United States ◽  
Late Triassic ◽  
Vertebrate Paleontology ◽  
Unique Combination ◽  
Epistemological Problem ◽  
Chinle Formation

Calyptosuchus wellesiis a medium-sized desmatosuchian aetosaur common in Adamanian (early to middle Norian) age rocks from the Chinle Formation and Dockum Group of the Western United States. Known chiefly from osteoderms, this taxon has never been fully described and non-osteoderm material assigned toCalyptosuchushas been done so based on questionable criteria. Mapping of aetosaurian elements from thePlaceriasQuarry allows for the recognition of associated material providing support for referrals of non-osteoderm material. Furthermore, another previously undescribed specimen from the Chinle Formation of Arizona provides more details about this taxon. PresentlyCalyptosuchuslacks discrete autapomorphies, but can be distinguished from other aetosaurs based on a unique combination of characters supported by a phylogenetic analysis.Calyptosuchusis one of the most common aetosaurians in the Western United States and an index taxon of the early Adamanian biozone. The nameCalyptosuchusis retained and encouraged as the applicable genus name for the specieswellesirather than the often usedStagonolepisbecause assignments of taxa to multi-species genus names are problematic and in this case provides a proposed taxonomic relationship that cannot be unambiguously supported, even by phylogenetic analyses. Because of the inherent limitations of the fossil record, referral of specimens and species to species and genera respectively is an epistemological problem in vertebrate paleontology.

A reappraisal of the systematics, biogeography, and evolution of fossil horses

Paleobiology ◽  
1982 ◽  
Vol 8 (4) ◽  
pp. 315-327 ◽  
Author(s):  
M. O. Woodburne ◽  
Bruce J. MacFadden
Keyword(s):  
United States ◽  
Fossil Record ◽  
Evolutionary Rates ◽  
Western United States ◽  
Vertebrate Paleontology ◽  
Evolutionary Trends ◽  
Evolutionary Pattern ◽  
Major Mode ◽  
The Rich

The founders of North American vertebrate paleontology, F. V. Hayden, Joseph Leidy, E. D. Cope, O. C. Marsh, and their colleagues, collected and described the first suites of fossil mammals obtained from the rich Tertiary successions of the western United States. Among them were remains of fossil horses, and subsequent study of these resulted in an interpretation that supported the concept of Darwinian gradualism as the major mode of evolution. The fossil record of horses also contributed importantly to the demise of orthogenesis as an evolutionary pattern, and to the evaluation of evolutionary rates and long-term evolutionary trends in a major phyletic group of organisms.

scholarly journals Testing pterosaur ingroup relationships through broader sampling of avemetatarsalian taxa and characters and a range of phylogenetic analysis techniques

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9604
Author(s):  
Matthew G. Baron
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Phylogenetic Analyses ◽  
Sensu Stricto ◽  
Late Triassic ◽  
Sister Taxon ◽  
Analysis Techniques ◽  
Close Relationship ◽  
Anatomical Characters ◽  
First Time

The pterosaurs first appear in the fossil record in the middle of the Late Triassic. Their earliest representatives are known from Northern Hemisphere localities but, by the end of the Jurassic Period, this clade of flying reptiles achieved a global distribution, as well as high levels of diversity and disparity. Our understanding of early pterosaur evolution and the fundamental interrelationships within Pterosauria has improved dramatically in recent decades. However, there is still debate about how the various pterosaur subgroups relate to one another and about which taxa comprise these. Many recent phylogenetic analyses, while sampling well from among the known Triassic and Early Jurassic pterosaurs, have not included many non-pterosaurian ornithodirans or other avemetatarsalians. Given the close relationship between these groups of archosaurs, the omission of other ornithodirans and avemetatarsalians has the potential to adversely affect the results of phylogenetic analyses, in terms of character optimisation and ingroup relationships recovered. This study has addressed this issue and tests the relationships between the early diverging pterosaur taxa following the addition of avemetatarsalian taxa and anatomical characters to an existing early pterosaur dataset. This study has, for the first time, included taxa that represent the aphanosaurs, lagerpetids, silesaurids and dinosaurs, in addition to early pterosaurs. Anatomical characters used in other recent studies of archosaurs and early dinosaurs have also been incorporated. By expanding the outgroup taxa and anatomical character coverage in this pterosaur dataset, better resolution between the taxa within certain early pterosaur subclades has been achieved and stronger support for some existing clades has been found; other purported clades of early pterosaurs have not been found in this analysis—for example there is no support for a monophyletic Eopterosauria or Eudimorphodontidae. Further support has been found for a sister-taxon relationship between Peteinosaurus zambelli and Macronychoptera, a clade here named Zambellisauria (clade nov.), as well as for a monophyletic and early diverging Preondactylia. Some analyses also support the existence of a clade that falls as sister-taxon to the zambellisaurs, here named Caviramidae (clade nov.). Furthermore, some support has been found for a monophyletic Austriadraconidae at the base of Pterosauria. Somewhat surprisingly, Lagerpetidae is recovered outside of Ornithodira sensu stricto, meaning that, based upon current definitions at least, pterosaurs fall within Dinosauromorpha in this analysis. However, fundamental ornithodiran interrelationships were not the focus of this study and this particular result should be treated with caution for now. However, these results do further highlight the need for broader taxon and character sampling in phylogenetic analyses, and the effects of outgroup choice on determining ingroup relationships.

scholarly journals Tetrapod extinctions during the Late Triassic: evidence from the western United States

1992 ◽  
Vol 6 ◽  
pp. 142-142
Author(s):  
Adrian P. Hunt ◽  
Spencer G. Lucas
Keyword(s):  
United States ◽  
Fossil Record ◽  
Western United States ◽  
Late Triassic ◽  
Great Area ◽  
Stratigraphic Record ◽  
Facies Change ◽  
Extensive Collection ◽  
Chinle Group ◽  
Early Late

Most recent workers have identified a major extinction of nonmarine tetrapods during the Late Triassic at the Carnian-Norian boundary. However, this identification is based principally on the stratigraphic distribution of tetrapods where there either is a major facies change at the Carnian-Norian boundary (Germany) or a significant unconformity that spans much of the early Norian (Argentina). Instead, we have examined the stratigraphic record of tetrapods in the western United States (Chinle Group) where there is a relatively continuous, nonmarine depositional and fossil record across the Carnian-Norian boundary that does not encompass major facies changes. The Chinle Group, because of its great area of exposure, more than one century of extensive collection and relatively complete publication, contains the world's best record of tetrapods across the Carnian-Norian boundary.The tetrapod record from the Chinle Group does not record a significant tetrapod extinction at the Carnian-Norian boundary. Instead, it documents a staggered extinction of some taxa during the late Carnian and the persistence of most taxa across the Carnian-Norian boundary. Thus, rhynchosaurs become extinct at the end of the early-late Carnian, whereas dicynodonts become extinct somewhat later, during the latest Carnian. Among metoposaurids, only the large taxa (Buettneria) disappear at the end of the Carnian. Other groups - phytosaurs, aetosaurs, rauisuchians, trilophosaurs, etc. - only exhibit some generic turnover at the Carnian-Norian boundary. The first appearance of dinosaurs, linked by some to a Carnian-Norian tetrapod extinction, is well in advance of the end of the Carnian. Thus, we conclude that the highest resolution tetrapod record of the late Carnian and early Norian does not document a significant tetrapod extinction at the end of the Carnian.

The first potential fossil record of a dibamid reptile (Squamata: Dibamidae): a new taxon from the early Oligocene of Central Mongolia

2019 ◽  
Vol 187 (3) ◽  
pp. 782-799 ◽  
Author(s):  
Andrej Čerňanský
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Phylogenetic Analyses ◽  
New Taxon ◽  
Unique Combination ◽  
Central Mongolia ◽  
Squamate Reptiles ◽  
The Past ◽  
Early Oligocene ◽  
Fossil Material

Abstract Dibamid reptiles have a known current distribution on two continents (Asia and North America). Although this clade represents an early-diverging group in the Squamata and thus should have a long evolutionary history, no fossil record of these peculiar burrowing squamate reptiles has been documented so far. The fossil material described here comes from the early Oligocene of the Valley of Lakes in Central Mongolia. This material consists of jaws and is placed in the clade Dibamidae on the basis of its morphology, which is further confirmed by phylogenetic analyses. In spite of the fragmentary nature of this material, it thus forms the first, but putative, fossil evidence of this clade. If correctly interpreted, this material demonstrates the occurrence of Dibamidae in East Asia in the Palaeogene, indicating its distribution in higher latitudes than today. The preserved elements possess a unique combination of character states, and a new taxon name is therefore erected: Hoeckosaurus mongoliensis sp. nov. The dentary of Hoeckosaurus exhibits some characters of the two extant dibamid taxa. However, the open Meckel’s groove, together with other characters, show that this group was morphologically much more diverse in the past.

REVIEW OF THE MYRMECOPHILOUS PTOMAPHAGUS, SUBGENUS ECHINOCOLEUS (NEW STATUS), OF NORTH AMERICA (COLEOPTERA: LEIODIDAE: CHOLEVINAE: PTOMAPHAGINI)

1997 ◽  
Vol 129 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Stewart B. Peck ◽  
Pedro Gnaspini
Keyword(s):  
United States ◽  
Phylogenetic Analysis ◽  
North America ◽  
Body Length ◽  
Southeastern United States ◽  
Western United States ◽  
Harvester Ants

AbstractWe here give Echinocoleus new ranking as a subgenus of Ptomaphagus. Ptomaphagus (Echinocoleus) acutus sp.nov. is described from the southeastern United States (Alabama, Georgia, Florida). It is the most plesiotypic member of a group in which all other species live in the western United States and (probably) adjacent Mexico. All are myrmecophilous with Pogonomyrmex and Aphaenogaster (= Novomessor) harvester ants. A phylogenetic analysis is given for the subgenus. The main synapomorphies of Echinocoleus, which are mostly interrelated with myrmecophily, are reduction of body length and broadening of elytra, reduction of antennal length, verticalization of mesocoxal insertion, reduction of mesosternal carina, body with a golden pubescense, and a pointed projection at the end of the spermatheca.

Phylogenetic relationships of human and wildlife piroplasm isolates in the western United States inferred from the 18S nuclear small subunit RNA gene

Parasitology ◽  
2000 ◽  
Vol 120 (5) ◽  
pp. 487-493 ◽  
Author(s):  
A. M. KJEMTRUP ◽  
J. THOMFORD ◽  
T. ROBINSON ◽  
P. A. CONRAD
Keyword(s):  
United States ◽  
Ribosomal Rna ◽  
Phylogenetic Relationships ◽  
Phylogenetic Analyses ◽  
Mule Deer ◽  
Odocoileus Hemionus ◽  
Small Subunit ◽  
Western United States ◽  
Ribosomal Rna Gene ◽  
Wildlife Species

The 18S nuclear small subunit ribosomal RNA gene of piroplasms from wildlife and human cases of babesiosis in the western USA were isolated by PCR and sequenced. Phylogenetic analyses of these sequences and comparisons with sequences from other Babesia and Theileria species revealed that piroplasm isolates from the human cases were indistinguishable from some of the isolates from the western wildlife species, most notably the isolates from mule deer (Odocoileus hemionus). These results suggest that large ungulates may serve as reservoirs for human piroplasm infection. The western piroplasm isolates from humans and wildlife formed a distinct clade, separate from other piroplasms found worldwide.

Venation pattern and revision of Orthoptera sensu nov. and sister groups. Phylogeny of Palaeozoic and Mesozoic Orthoptera sensu nov.

Zootaxa ◽  
2002 ◽  
Vol 96 (1) ◽  
pp. 1 ◽  
Author(s):  
OLIVIER BÉTHOUX ◽  
ANDRÉ NEL
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Phylogenetic Analyses ◽  
Wing Venation ◽  
Venation Pattern ◽  
Biodiversity Crisis ◽  
Paraphyletic Group ◽  
New Interpretation ◽  
Orthopteroid Insects ◽  
First Time

After the revision of several fossils and observations of recent taxa, we propose a new interpretation of the wing venation pattern for the ‘orthopteroid lineage’. The Orthoptera and several taxa previously assigned to the paraphyletic group ‘Protorthoptera’ are included in a common clade, Archaeorthoptera taxon nov. The Orthoptera and some closest relative groups are included in the Panorthoptera sensu nov. These assignments are based on new autapomorphies based on venation patterns. A cladistic phylogenetic analysis of the Orthoptera is performed for the first time on the fossil record of this group, based on 74 characters (131 informative states). Three taxa assigned to the Archaeorthoptera nec Panorthoptera compose the outgroup. The ingroup is composed of three Panorthoptera nec Orthoptera and 63 Orthoptera, mainly from the Palaeozoic and Mesozoic. Following this initial phylogeny, we propose several nomenclatural changes; the Ensifera are redefined and the relationships between Caelifera and Ensifera sensu nov., and those between the major clades of modern Ensifera sensu nov., are clarified. Relationships within the ‘oedischioid’ stem-group remain unclear. The evolution of the venational structures within the Orthoptera is discussed and in this analysis the Orthoptera were not clearly affected by the Permo-Triassic biodiversity “crisis”. The capacity of the fossil taxa to be used in phylogenetic analyses is discussed, using the example of the ‘orthopteroid’ insects.

scholarly journals Oldest cingulate skulls provide congruence between morphological and molecular scenarios of armadillo evolution

2011 ◽  
Vol 278 (1719) ◽  
pp. 2791-2797 ◽  
Author(s):  
Guillaume Billet ◽  
Lionel Hautier ◽  
Christian de Muizon ◽  
Xavier Valentin
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Phylogenetic Analyses ◽  
Typical Case ◽  
New Taxon ◽  
Late Oligocene ◽  
Phylogenetic Studies ◽  
Molecular Phylogenetic ◽  
Early Neogene ◽  
Group A

The cingulates of the mammalian order Xenarthra present a typical case of disagreement between molecular and morphological phylogenetic studies. We report here the discovery of two new skulls from the Late Oligocene Salla Beds of Bolivia (approx. 26 Ma), which are the oldest known well-preserved cranial remains of the group. A new taxon is described: Kuntinaru boliviensis gen. et sp. nov. A phylogenetic analysis clusters K. boliviensis together with the armadillo subfamily Tolypeutinae. These skulls document an early spotty occurrence for the Tolypeutinae at 26 Ma, in agreement with the temporal predictions of previous molecular studies. The fossil record of tolypeutines is now characterized by a unique occurrence in the Late Oligocene, and a subsequent 12 Myr lack in the fossil record. It is noteworthy that the tolypeutines remain decidedly marginal in the Late Palaeogene and Early Neogene deposits, whereas other cingulate groups diversify. Also, the anatomical phylogenetic analysis herein, which includes K. boliviensis , is congruent with recent molecular phylogenetic analyses. Kuntinaru boliviensis is the oldest confident calibration point available for the whole Cingulata.

scholarly journals Modeling Dragons: Using linked mechanistic physiological and microclimate models to explore environmental, physiological, and morphological constraints on the early evolution of dinosaurs

2019 ◽  
Author(s):  
David M. Lovelace ◽  
Scott A. Hartman ◽  
Paul D. Mathewson ◽  
Benjamin J. Linzmeier ◽  
Warren P. Porter
Keyword(s):  
Fossil Record ◽  
Resting Metabolic Rate ◽  
Late Triassic ◽  
Sensitivity Testing ◽  
Metabolic Chamber ◽  
Chinle Formation ◽  
Modeling Software ◽  
Temperature Ranges ◽  
Metabolic Variables ◽  
Hot Environments

AbstractWe employed the widely-tested biophysiological modeling software, Niche Mapper™ to investigate the metabolic function of Late Triassic dinosaurs Plateosaurus and Coelophysis during global greenhouse conditions. We tested them under a variety of assumptions about resting metabolic rate, evaluated within six microclimate models that bound paleoenvironmental conditions at 12° N paleolatitude, as determined by sedimentological and isotopic proxies for climate within the Chinle Formation of the southwestern United States. Sensitivity testing of metabolic variables and simulated “metabolic chamber” analyses support elevated “ratite-like” metabolic rates and intermediate “monotreme-like” core temperature ranges in these species of early saurischian dinosaur. Our results suggest small theropods may have needed partial to full epidermal insulation in temperate environments, while fully grown prosauropods would have likely been heat stressed in open, hot environments and should have been restricted to cooler microclimates such as dense forests (under any vegitative cover) or those seen at higher latitudes and elevations. This is in agreement with the Late Triassic fossil record and may have contributed to the latitudinal gap in the Triassic prosauropod record.

An unusual new basal iguanodont (Dinosauria: Ornithopoda) from the Lower Cretaceous of Teruel, Spain

Zootaxa ◽  
2012 ◽  
Vol 3595 (1) ◽  
pp. 61 ◽  
Author(s):  
ANDREW T. MCDONALD ◽  
EDUARDO ESPÍLEZ ◽  
LUIS MAMPEL ◽  
JAMES I. KIRKLAND ◽  
LUIS ALCALÁ
Keyword(s):  
Phylogenetic Analysis ◽  
Lower Cretaceous ◽  
Fossil Record ◽  
New Taxon ◽  
Unique Combination ◽  
Preliminary Phylogenetic Analysis

We describe a new basal iguanodont, Proa valdearinnoensis, from the Lower Cretaceous (lower Albian) EscuchaFormation of Teruel Province, Spain. The new taxon is known from abundant cranial and postcranial material belongingto several individuals, and is distinguished by an autapomorphy (predentary comes to a point at its rostral margin, withdivergent lateral processes) and a unique combination of characters. Proa fills part of an otherwise lengthy temporal gap(early Aptian–Santonian) in the European fossil record of basal iguanodonts. A preliminary phylogenetic analysis placesProa in a polytomy with Iguanodon bernissartensis and more derived iguanodontians (Hadrosauroidea). Proa is morebasal than the Valanginian Hypselospinus and late Barremian-early Aptian Mantellisaurus, suggesting a long ghost lineage leading to Proa.

Sign in / Sign up

Export Citation Format

Share Document