A Winteraceae pollen tetrad from the early Paleocene of western Greenland, and the fossil record of Winteraceae in Laurasia and Gondwana

2017 ◽  
Vol 45 (3) ◽  
pp. 567-581 ◽  
Author(s):  
Friðgeir Grímsson ◽  
Guido W. Grimm ◽  
Alastair J. Potts ◽  
Reinhard Zetter ◽  
Susanne S. Renner
Keyword(s):  
Fossil Record ◽  
Early Paleocene ◽  
Pollen Tetrad

The tale of the headless turtle

Zootaxa ◽  
2016 ◽  
Vol 4200 (2) ◽  
pp. 327 ◽  
Author(s):  
PEDRO S. R. ROMANO
Keyword(s):  
New Species ◽  
Phenotypic Plasticity ◽  
Lower Cretaceous ◽  
Fossil Record ◽  
Diagnostic Features ◽  
Fossil Species ◽  
The Past ◽  
Early Paleocene ◽  
Phylogenetic Hypotheses ◽  
A New Species

Pelomedusoides is the most diverse clade of side-necked turtles and there is an extensive fossil record (de Broin, 1988; Lapparent de Broin, 2000; Gaffney et al., 2006, 2011) that dates back at least to the Barremian (Lower Cretaceous) (Romano et al., 2014). Its large fossil record evidences a greater diversity in the past, particularly at the end of the Mesozoic, and exhibits a good sampling of species that are represented by skull material (Gaffney et al., 2006, 2011). As a consequence, the most complete and recent phylogenetic hypotheses for this clade (e.g. Romano et al., 2014; Cadena, 2015) are based on matrices comprising a great amount of cranial characters derived largely from Gaffney et al. (2006, 2011). In addition, it is well established that shell characters show a lot of phenotypic plasticity, even in the fossil species (Romano, 2008; Gaffney et al., 2006, 2011). In most cases it consequently is not justified to rely on “diagnostic features” of poorly informative shell-only material for describing a new species. Because of that, most authors remark new morphotypes in the literature when such aberrant specimens are recovered, but do not make any nomenclatural act by proposing a new yet poorly supported species (e.g. Romano et al., 2013; Ferreira & Langer, 2013; Menegazzo et al., 2015). Unfortunately, such a supposedly new bothremydid turtle (Pleurodira: Bothremydidae) from the Early Paleocene of Brazil was recently described based on poorly diagnostic remains (Carvalho et al., 2016; hereafter CGB, for the authors initials) and a correction of this unfounded nomenclatural act is required. In addition I present some comments on shell only material from Brazil in order to guide splitter-taxonomists to stop describing poorly preserved fossil specimens as new species. 

CIRCULAR OR SPHERICAL VESSELS IN THE FOSSIL RECORD

IAWA Journal ◽  
2015 ◽  
Vol 36 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Pieter Baas ◽  
Rashmi Srivastava ◽  
Steven R. Manchester ◽  
Elisabeth A. Wheeler
Keyword(s):  
Late Cretaceous ◽  
Fossil Record ◽  
Central India ◽  
Type Specimen ◽  
Axillary Buds ◽  
Before Present ◽  
Early Paleocene

Strangely configured vessels composed of few elements interconnected in a sphere- or ring-like structure are reported from the type specimen of Amooroxylon deccanensis Bande & Prakash, a large fossil trunk from the Deccan Intertrappean Beds of central India (late Cretaceous-early Paleocene, about 66 MY before present). In the recent flora, circular vessels have been found mainly in association with branching nodes, axillary buds, wound callus, and pathogens, and they have been artificially induced by auxin. The presence of circular vessels in this fossil trunk showing no signs of branching or trauma makes this record highly unusual.

Paleocene diversification of bucciniform gastropods on Seymour Island, Antarctica

1996 ◽  
Vol 70 (6) ◽  
pp. 923-934 ◽  
Author(s):  
Anton E. Oleinik ◽  
William J. Zinsmeister
Keyword(s):  
New Species ◽  
Mass Extinction ◽  
Fossil Record ◽  
New Genus ◽  
Shell Morphology ◽  
Geographic Isolation ◽  
Extinction Event ◽  
Early Paleocene ◽  
Mass Extinction Event ◽  
Seymour Island

Following the mass extinction event at the end of the Cretaceous, the marine molluscan faunas of the high southern latitudes underwent a marked period of diversification during the early Paleocene. The appearance of four new species belonging to the new genus Seymourosphaera, tentatively placed in the subfamily Pseudolivinae, from the lower Paleocene strata of Seymour Island, Antarctic Peninsula, clearly illustrates the post-Cretaceous extinction diversification. The abrupt radiation of the buccinids during the early Paleocene, was also apparently related to geographic isolation of Antarctica during final breakup of Gondwana. Comparative analysis of shell morphology of Seymourosphaera, new genus reveals close morphologic similarities, not only with taxa within Pseudolivinae, but also with several genera and subgenera belonging to the families Buccinidae and Nassariidae. However, incompleteness of the fossil record and a “generalized” shell morphology make difficult establishment of unequivocal phylogenetic relationships for Seymourosphaera. A taxonomic review of most closely related, and possibly ancestral genus Austrosphaera Camacho, 1949, is provided. The following new species of genus Seymourosphaera new genus are described: Seymourosphaera bulloides new species, S. subglobosa new species, S. depressa new species, and S. elevata new species.

scholarly journals Rapid morphological evolution in placental mammals post-dates the origin of the crown group

2019 ◽  
Vol 286 (1898) ◽  
pp. 20182418 ◽  
Author(s):  
Thomas J. D. Halliday ◽  
Mario dos Reis ◽  
Asif U. Tamuri ◽  
Henry Ferguson-Gow ◽  
Ziheng Yang ◽  
...  
Keyword(s):  
Fossil Record ◽  
Morphological Evolution ◽  
Relative Rate ◽  
Molecular Data ◽  
Placental Mammal ◽  
Dental Morphology ◽  
Crown Group ◽  
Rates Of Evolution ◽  
Early Paleocene ◽  
Molecular Evolutionary Rates

Resolving the timing and pattern of early placental mammal evolution has been confounded by conflict among divergence date estimates from interpretation of the fossil record and from molecular-clock dating studies. Despite both fossil occurrences and molecular sequences favouring a Cretaceous origin for Placentalia, no unambiguous Cretaceous placental mammal has been discovered. Investigating the differing patterns of evolution in morphological and molecular data reveals a possible explanation for this conflict. Here, we quantified the relationship between morphological and molecular rates of evolution. We show that, independent of divergence dates, morphological rates of evolution were slow relative to molecular evolution during the initial divergence of Placentalia, but substantially increased during the origination of the extant orders. The rapid radiation of placentals into a highly morphologically disparate Cenozoic fauna is thus not associated with the origin of Placentalia, but post-dates superordinal origins. These findings predict that early members of major placental groups may not be easily distinguishable from one another or from stem eutherians on the basis of skeleto-dental morphology. This result supports a Late Cretaceous origin of crown placentals with an ordinal-level adaptive radiation in the early Paleocene, with the high relative rate permitting rapid anatomical change without requiring unreasonably fast molecular evolutionary rates. The lack of definitive Cretaceous placental mammals may be a result of morphological similarity among stem and early crown eutherians, providing an avenue for reconciling the fossil record with molecular divergence estimates for Placentalia.

New cyriacotheriid pantodonts (Mammalia, Pantodonta) from the Paleocene of Alberta, Canada, and the relationships of Cyriacotheriidae

2010 ◽  
Vol 84 (2) ◽  
pp. 197-215 ◽  
Author(s):  
Craig S. Scott
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Fossil Record ◽  
Evolutionary History ◽  
New Genus ◽  
The Family ◽  
Two New Species ◽  
Unusual Combination ◽  
Early Paleocene ◽  
History Of

Cyriacotheriidae are a family of unusual small-bodied pantodonts known from the Paleocene of the Western Interior of North America. Cyriacotheriids possess a suite of dental characters similar to that of pantodonts (e.g., molar dilambdodonty, lingual molar hypoconulids), as well as several divergent features (e.g., molarized premolars, strong molar conules) that have been interpreted as “dermopteran-like.” the unusual combination of pantodont and dermopteran-like characters, combined with a limited fossil record, has made attempts at understanding the broader relationships of Cyriacotheriidae difficult. This paper reports on a new genus and two new species of cyriacotheriids from the Paleocene of Alberta, Canada, with both species significantly older than those of the only previously described cyriacotheriid, Cyriacotherium. Collectively, the dentitions of these new taxa exhibit derived characters seen in Cyriacotherium (e.g., robust molar conules, strong molar dilambdodonty) in addition to a number of plesiomorphies seen in more basal pantodonts (e.g., conspicuous molar entoconids, deep premolar ectoflexus) and, importantly, posterior premolars that are weakly molariform and non-dilambdodont. A phylogenetic analysis of the new cyriacotheriid, basal pantodonts, dermopterans, and dermopteran-like eutherians resulted in Cyriacotheriidae nesting within a monophyletic Pantodonta. the results strengthen previous hypotheses regarding the pantodont affinities of the family, and suggest that the dermopteran-like features seen in the more derived Cyriacotherium were acquired convergently. Although the discovery of new cyriacotheriids sheds light on the evolutionary history of the family, it cannot resolve the ongoing questions of pantodont origins; nonetheless, their discovery in strata of early Paleocene age indicates that significant parts of the evolutionary history of Cyriacotheriidae, and North American pantodonts more generally, have yet to be discovered.

Cf. Wortmania from the early Paleocene of Montana and an evaluation of the fossil record of the initial diversification of the Taeniodonta (Mammalia)

2013 ◽  
Vol 50 (3) ◽  
pp. 341-354 ◽  
Author(s):  
William A. Clemens
Keyword(s):  
Fossil Record ◽  
Phylogenetic Analyses ◽  
Future Research ◽  
San Juan ◽  
Local Fauna ◽  
San Juan Basin ◽  
The North ◽  
Early Paleocene ◽  
Land Mammal ◽  
Channel Deposits

The Garbani Channel deposits, part of the Tullock Formation exposed in northeastern Montana, have yielded a large sample of vertebrates that probably lived during the Puercan 3 North American Land Mammal Age (NALMA). Four fossils in this sample — three isolated teeth and a medial phalanx — document the presence of a stylinodontid taeniodont, cf. Wortmania. Discovery of cf. Wortmania in the Tullock Formation extends the documented range of taeniodonts during Puercan 3 approximately 500 miles (800 km) northward from the San Juan Basin, New Mexico. Evaluation of the oldest records of taeniodonts, from the Lancian, Puercan, and Torrejonian NALMAs, highlights biases warranting future research. Recent phylogenetic analyses that resulted in numerous ghost lineages indicate that the available fossil record is far from complete. They open the possibility that the origin and initial radiation of taeniodonts occurred in areas yet to be sampled and their first occurrences might reflect immigration of invasive species. The available fossil record of taeniodonts is biased with significantly more abundant and complete specimens discovered in the San Juan Basin than at localities to the north. This bias is also apparent in the available samples of two other lineages of large Puercan mammals, the multituberculate Taeniolabis and the “triisodontid” Eoconodon. Where they occur, taeniodonts are relatively rare members of any local fauna. Is their rarity a product of an ecological bias or a reflection of decreasing population size related to increasing body size?

Distinguishing Agromyzidae (Diptera) Leaf Mines in the Fossil Record: New Taxa from the Paleogene of North America and Germany and Their Evolutionary Implications

2010 ◽  
Vol 84 (5) ◽  
pp. 935-954 ◽  
Author(s):  
Isaac S. Winkler ◽  
Conrad C. Labandeira ◽  
Torsten Wappler ◽  
Peter Wilf
Keyword(s):  
North America ◽  
Host Plant ◽  
Fossil Record ◽  
Middle Eocene ◽  
Phytophagous Insects ◽  
The Past ◽  
Plant Associations ◽  
Leaf Mining ◽  
Early Paleocene ◽  
History Of

Fossilized leaf mines and other traces of phytophagous insects provide a unique window into ecological and evolutionary associations of the past. Leaf-mining flies (Diptera: Agromyzidae) are an important component of the recent leaf-mining fauna, but their fossil record is sparse compared to other mining insect lineages; many putative agromyzid body fossils and traces are dubiously assigned. Agromyzid leaf mines often can be distinguished from those of other insects by the presence of an intermittent, fluidized frass trail that may alternate between the sides of the mine. Here, we describe two new Paleogene leaf mine fossils, Phytomyzites biliapchaensis Winkler, Labandeira and Wilf n. sp. from the early Paleocene of southeastern Montana, USA, occurring in leaves of Platanus raynoldsii (Platanaceae); and Phytomyzites schaarschmidti Wappler n. sp., from the middle Eocene of Messel, Germany, occurring in leaves of Toddalia ovata (Rutaceae). These fossils both exhibit frass trails indicative of an agromyzid origin, and P. biliapchaensis also exhibits associated stereotypical marks identical to damage caused by feeding punctures of extant adult female Agromyzidae prior to oviposition. Phytomyzites biliapchaensis represents the earliest confirmed record of Agromyzidae, and one of the earliest records for the large dipteran clade Schizophora. Plant hosts of both species belong to genera that are no longer hosts of leaf-mining Agromyzidae, suggesting a complex and dynamic history of early host-plant associations and, for the early Paleocene example, an evolutionary, possibly opportunistic colonization in the midst of the ecological chaos following the end-Cretaceous event in North America.

scholarly journals A morphological study of vertebral centra in extant species of pike, Esox (Teleostei: Esociformes)

2019 ◽  
Vol 7 ◽  
pp. 111-128
Author(s):  
Sinjini Sinha ◽  
Don B Brinkman ◽  
Alison M. Murray
Keyword(s):  
Late Cretaceous ◽  
Fossil Record ◽  
Morphological Study ◽  
Vertebral Column ◽  
Early History ◽  
Vertebral Centra ◽  
Extant Species ◽  
The Family ◽  
Early Paleocene ◽  
History Of

            Isolated centra of members of the Esocidae occur frequently in vertebrate microfossil localities of Late Cretaceous and early Paleocene age and are an important source of data on the early history of the family. However, morphological variation along the vertebral column can lead to incorrect interpretations of diversity if they are not recognized. To facilitate the use of centra for interpreting the diversity and distribution of esocids in Cretaceous vertebrate microfossil localities, the variation along the column in five extant species of esocids is described. Comparison with Cretaceous centra referred to the Esocidae allows identification of a series of features in which species of Esox differ from basal members of the family. These include the presence of a mid-ventral groove bordered by a pair of low budges on centra in the anterior end of the column, and antero-lateral processes on the posterior abdominal and anterior caudal centra. These differences provide a basis for recognizing early occurrences of the genus Esox in the fossil record and thus will allow centra to be used to document the timing of origin of the genus.

Taxonomy and distribution of the buccinid gastropod Brachysphingus from uppermost Cretaceous and Lower Cenozoic marine strata of the Pacific Slope of North America

1997 ◽  
Vol 71 (5) ◽  
pp. 847-861 ◽  
Author(s):  
Richard L. Squires
Keyword(s):  
North America ◽  
Fossil Record ◽  
Turbidity Currents ◽  
Early Eocene ◽  
Shallow Marine ◽  
Marine Strata ◽  
Late Paleocene ◽  
The Pacific ◽  
Early Paleocene ◽  
Pacific Slope

Brachysphingus is a low-spired bucciniform neogastropod known only from the fossil record of California and northern Baja California. The earliest species, Brachysphingus gibbosus Nelson, 1925, ranges in age from latest Cretaceous or possibly earliest Paleocene to the late Paleocene. During the early Paleocene, the smoothish B. gibbosus evolved into the axially ribbed B. sinuatus Gabb, 1869, which is the senior primary synonym of B. gabbi Stewart, 1927. During the late Paleocene, B. sinuatus evolved into B. mammilatus Clark and Woodford, 1927, which is the youngest species of Brachysphingus and which lasted into the early Eocene.All three species of Brachysphingus were shallow-marine dwellers subject to transport into deeper waters via turbidity currents.

First report ofOniscidiaMörch, 1852 (Neogastropoda, Harpidae) in the northeast Pacific fossil record and paleobiogeographic review of the genus

2018 ◽  
Vol 92 (5) ◽  
pp. 794-803
Author(s):  
Richard L. Squires
Keyword(s):  
Fossil Record ◽  
Middle Eocene ◽  
Turbidity Currents ◽  
Northeast Pacific ◽  
Early Paleocene ◽  
History Of ◽  
Taxonomic Confusion ◽  
The Caribbean ◽  
First Time ◽  
The Western Pacific

AbstractThe harpid neogastropod genusOniscidiaMörch, 1852, which has not been recognized before in the northeast Pacific fossil record, is represented there by rare specimens ofOniscidia plectata(Waring, 1917) n. comb., of late early Paleocene age, in a region extending from southern California, USA to Baja California, Mexico. This species is the earliest unequivocal record ofOniscidiaand its only known Paleocene record. It apparently lived in silty, inner- to middle-shelf depths, which were inherently cooler than adjacent shallower marine depths. Its habitat was subject to the influx of shallow-marine shells, especially turritellas, contained in turbidity currents emanating from nearshore depths.The global paleogeography ofOniscidia, which is presented here for the first time, has been overlooked previously because this genus has a long and complicated history of taxonomic confusion with the harpid genusMorumRöding, 1798.Oniscidiaquestionably originated during the Late Cretaceous (Campanian) in southern India and apparently dispersed westward through the Tethys Seaway into the New World. Paleocene and early Eocene occurrences of this genus are rare, and middle Eocene occurrences are uncommon. During the cool times of the Oligocene and into the early Miocene, it was most widespread. Its range became restricted during the middle Miocene and continued to be so during the Pliocene, Pleistocene, and modern day, with occurrences only in the Caribbean Sea region, Florida, and the western Pacific. Its distribution through warm and cool times was most likely controlled by its habitat preference for relatively deep cool waters.

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