The dentition and relationships of the Paleocene primate Micromomys Szalay, with description of a new species

1984 ◽  
Vol 21 (11) ◽  
pp. 1262-1267 ◽  
Author(s):  
Richard C. Fox

Nearly complete lower dentitions (with c?, p2–4, m1–3) and the first discovered upper dentitions (with P2–4, M1–3) are described and illustrated for the late Paleocene primate Micromomys Szalay. These fossils, from the Paskapoo Formation of central Alberta, Canada, represent a new species, the geologically earliest known species of the genus. Micromomys appears to have been a primitive microsyopid most closely related to the early Paleocene Purgatorius Van Valen and Sloan and the middle Paleocene Palenochtha Gidley; a relationship between Micromomys and the early Eocene Tinimomys Szalay may not be as near as previous workers had supposed.Micromomys is the smallest primate known and was probably insectivorous. Its occurrence with the rare European primate Saxonella Russell, a new, primitive carpolestid, and an unusual mammal possibly related to palaeanodonts documents a facies not yet encountered in other Paleocene mammal local faunas, in Canada or elsewhere.

2010 ◽  
Vol 47 (12) ◽  
pp. 1451-1462 ◽  
Author(s):  
Craig S. Scott

Mixodectidae (Mammalia, Archonta) are an unusual, poorly known family of dermopteran-like mammals that have been discovered at several North American localities of primarily early Paleocene age. Among the three or four recognized mixodectid genera, Eudaemonema Simpson is perhaps one of the least understood, being known from only a few localities of late Torrejonian and earliest Tiffanian age. This paper reports on a new species of Eudaemonema from the late Paleocene of Alberta, Canada, that significantly extends the geographic and stratigraphic ranges of the genus. Eudaemonema webbi sp. nov. is known from middle and late Tiffanian localities in central and south central Alberta, and it represents the youngest and northernmost species of Eudaemonema so far discovered. E. webbi differs from the genotypic species E. cuspidata in being larger and in having a suite of dental characters (e.g., molariform posterior premolars, enlarged molar protocone and hypocone, development of a second grinding platform on the lower molars) that suggests an increased emphasis on grinding during mastication. E. webbi possesses several dental features (e.g., broad, shelf-like molar paraconid–paracristid, lingually shifted molar hypoconulid) that resemble those of cynocephalids (Mammalia, Dermoptera), with these resemblances interpreted herein as convergent. The occurrence of E. webbi at Gao Mine extends the stratigraphic range of Eudaemonema into the late Tiffanian (Ti5) and represents the youngest known record of Mixodectidae.


1978 ◽  
Vol 56 (9) ◽  
pp. 1136-1152 ◽  
Author(s):  
Leo J. Hickey ◽  
Rayma Kempinsky Peterson

Zingiberopsis attenuata Hickey and Peterson is a new species of monocotyledon from the Paleocene Paskapoo Formation of Alberta. Leaves of this species with their parallel veins grouped into three size sets are intermediate between the Late Cretaceous Zingiberopsis magnifolia (Knowlton) Hickey, new combination, with four discrete sets and Zingiberopsis isonervosa Hickey, of late Paleocene and early Eocene age, with only one set. Zingiberopsis has large, elliptic to ovate leaves with a costa composed of a number of concurrent strands, a set of parallel veins emerging at low angles from the costa, and relatively distantly spaced transverse veins running between adjacent parallel veins. Morphology of the genus matches that of Alpinia in the Zingiberaceae except for greater irregularity of the parallel vein set at and near their origin on the costa and the lack of any evidence of a ligule on the petiole as in Alpinia. Species of Zingiberopsis demonstrate a clear trend toward loss of the wider parallel vein subsets over the approximately 20-million-year range of the genus. In addition, the overlooked character of the arrangement of the parallel vein subsets across the width of the leaf may have potential in the taxonomic determination of monocotyledonous leaves.


1995 ◽  
Vol 8 (6) ◽  
pp. 1035 ◽  
Author(s):  
LJ Scriven ◽  
RS Hill

The oldest known Casuarinaceae macrofossils, from late Paleocene sediments at Lake Bungarby in New South Wales, are assigned to a new species of Casuarinaceae, Gymnostoma antiquum. The nearest living relatives of this species are the Papua New Guinean Gymnostoma species and in particular one as yet unnamed species. Previous problems relating to the preparation, identification and description of Casuarinaceae macrofossils are examined and clarified. The ecology of both living Gymnostoma and G. antiquum are discussed. The decrease in catastrophic disturbance and climate seasonality during the Cenozoic were probably major contributing factors leading to the current distribution of Gymnostoma.


Zootaxa ◽  
2016 ◽  
Vol 4200 (2) ◽  
pp. 327 ◽  
Author(s):  
PEDRO S. R. ROMANO

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. 


2014 ◽  
Vol 147 (4) ◽  
pp. 359-369 ◽  
Author(s):  
S. Bruce Archibald ◽  
Vladimir N. Makarkin

AbstractArchaeochrysa sanikwanew species (Neuroptera: Chrysopidae: Nothochrysinae) is described from early Eocene (Ypresian) Okanagan Highlands shale at Driftwood Canyon, British Columbia, Canada. The evolutionary trends of three chrysopid wing venation characters (the shape of the intramedian cell, the position of the crossvein 2m-cu, and the development of the pseudocubitus) are analysed. The forewing venation of this species is very plesiomorphic compared with the vast majority species of Nothochrysinae, both fossil and extant.


1981 ◽  
Vol 36 (1-2) ◽  
pp. 128-137 ◽  
Author(s):  
Gregg F. Gunnell ◽  
Philip D. Gingerich

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