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Fossil eggs of clam shrimps (Spinicaudata) are rare and little attention has been paid to the study of their shape and microstructures. Here, we report the discovery of exceptionally preserved three-dimensional eggs from numerous specimens of Eosestheria elliptica Chen, 1976 from the lacustrine Early Cretaceous Yixian Formation in western Liaoning, China. These three-dimensionally preserved fossil eggs display a spherical shape with smooth surface, part of the tertiary envelope, and possibly the first embryonic cuticle, which were previously unknown or ambiguous. The eggs are abundant and assumed to be attached to the exopod as in extant Spinicaudata. Moreover, the exceptional three-dimensional preservation and delicate preparation of slices of the eggs allowed us to document the microstructures and elemental composition of fossil eggs of clam shrimps from the Jehol Biota. Energy dispersive spectroscopy of the fossilized envelope revealed a calcium phosphate composition. However, the egg contents display two completely different elemental compositions. Some exhibit the same elemental composition as the envelope, whereas others has been replaced by alumino-silicate. The taphonomic process is also briefly discussed in this paper.
This paper reports the successive occurrence of Ptychagnostus sinicusLu, 1957 and Ptychagnostusatavus (Tullberg, 1880) from the lower part of the Machari Formation, Yeongwol Group, Korea. Morphometric approaches of using the landmark and principal component analyses make it possible to differentiate P. sinicus from P. atavus with clarity: pygidia of P. sinicus have a relatively narrow M1, a transverse F2, and a weakly developed M2 tubercle, whereas those of P. atavus are characterized by a broadly arching M1, a chevron-shaped F2, and a prominent M2 tubercle. Recognition of P. atavus, for the first time in Korea, allows the determination of the base of the Drumian Stage in Korea and aids correlation with other parts of the world.
New Upper Ordovician trepostomate bryozoans from the eastern Anti-Atlas of Morocco have been identified. They have been collected from the lower and intermediate units of the Khabt-el-Hajar Formation, late Katian in age, representing, respectively, bryozoan-pelmatozoan meadows with siliciclastic input, degraded by wave activity in a mid-ramp setting, and outer-ramp environments with marly substrates. Ten species of the genera Cyphotrypa, Calloporella, Diplotrypa, Parvohallopora, Dekayia, and Aostipora are described. Of them, three species are new: Cyphotrypa regularis Jiménez-Sánchez, Parvohallopora cystata Jiménez-Sánchez, and Aostipora elongata Jiménez-Sánchez. Univariate statistical analyses of the sub-polar Moroccan species, in addition to other congeneric species of high, middle, and low latitudes, corroborate that for the trepostomate bryozoan the temperature of the ambient water was a primary control on zooecium size variations. Nevertheless, other environmental factors, besides temperature, must have also influenced significantly the zooid size, at least in low latitudes. Our data also give further support for considering the zooecium wall thickness as a limiting factor for the zooid size increment with latitude in the trepostomates.
Two new species of KalligrammulaHandlirsch, 1919 (Insecta, Neuroptera, Kalligrammatidae) are described as K. lata n. sp. and K. karatensis n. sp. based on two nearly complete hindwings respectively from the Middle—Upper Jurassic of Daohugou, China and the Upper Jurassic of Karatau, Kazakhstan. LimnogrammaRen, 2003 is considered to be a junior synonym of Kalligrammula based on the hindwing venation. The distribution of kalligrammatid genera is discussed.
Cambrian strata of the Laurentian craton contain numerous examples of Burgess Shale—type faunas. Although displaying a more or less concentric distribution around the cratonal margin, most faunal occurrences are in present-day western North America, extending from the Northwest Territories to California. Nevertheless, the soft-bodied and lightly skeletalized fossils in most of these Lagerstätten are highly sporadic. Here, we extend knowledge of such Middle Cambrian occurrences in Utah with reports of four taxa. An arthropod from the Marjum Formation, Dytikosicula desmatae gen. et sp. nov., is a putative megacheiran. It is most similar to Dicranocaris guntherorum, best known from the younger Wheeler Formation, but differs primarily in the arrangement of pleurae and overall size. Along with a specimen of ?Yohoia sp, a new species of Yohoia, Y. utahana sp. nov., is described. It differs from the type and only known species, Y. tenuis, principally in its larger size and shorter exopods; it is the first description of this genus from outside the Burgess Shale. A new species of a stem-group lophotrochozoan from the Spence Shale, Wiwaxia herka sp. nov., possesses a palisade of dorso-lateral spines that are more robust and numerous than the type species of Wiwaxia, W. corrugata. Another notable taxon is Eldonia ludwigi from the Marjum Formation, which is interpreted as a primitive ambulacrarian (assigned to the cambroernids) and a new specimen of the ?cnidarian Cambrorhytium from the Wheeler Shale is illustrated.
Palynomorph assemblages recovered from the Kanosh Shale at Fossil Mountain, Utah, are dominated by operculate acritarchs and cryptospores with minor smaller acritarchs. The present findings add new data to the largely incomplete knowledge of Ordovician acritarch assemblages from Laurentia, up to now known only from very few localities in North America. These populations contain some species in common with acritarchs from the Canning and Georgina basins in Australia and with assemblages from China; they indicate a Middle Ordovician (Dapingian-Darriwilian) age. The assemblage is lacking many typical marine acritarchs of this age, which, in combination with some cryptospores, is probably reflecting the likelihood of freshwater influence in the Kanosh Basin. This observation is congruent with previous interpretations of the depositional setting of the Kanosh Shale as a shallow water lagoon that supported the deposition of carbonate hardgrounds.
Four new taxa are described: Busphaeridium vermiculatum n. gen., n. sp.; Digitoglomus minutum n. gen., n. sp.; Turpisphaera heteromorpha n. gen., n. sp.; and Vermimarginata barbata n. gen., n. sp. In addition, the abundance of operculate forms has enabled the revision and a new emendation of the genus Dicommopalla and clarification of the “opalla” complex. We also propose new and revised suprageneric taxa that emphasize inferred biological differences among acritarch genera. The Sphaeromorphitae subgroup is emended to include forms lacking sculptural elements. Two new informal subgroups are proposed: the Superornamenti and the Operculate Acritarchs. Cryptospores are abundant throughout the sections studied and they appear to be more closely related to the late Cambrian Agamachates Taylor and Strother than to Darriwilian and younger Ordovician cryptospores from Gondwana.
A latest Changhsingian (latest Permian) foraminiferal fauna composed of 19 species (belonging to 10 genera) was recovered from the Daxiakou section in Xingshan County, Hubei Province, South China. Compared to contemporaneous faunas in South China, the Daxiakou fauna displays unique features: (1) nodosariids are the dominant forms in abundance and diversity; and (2) the most abundant forms have elongate and flattened tests, and include Geinitzina, Howchinella, and Ichthyolaria. The predominance of flattened elongate tests and their smaller size suggest that these foraminifers possibly lived in an oxygen-depleted, deep-water environment. Seven new species, Nodosaria quinquecostata n. sp., Howchinella inflata n. sp., H. hubeiensis n. sp., H. complanata n. sp., H. xiangxiensis n. sp., Ichthyolaria celsa n. sp., and Pseudotristix elongata n. sp. are described.
The class Somasteroidea Spencer, 1951, is basal within the subphylum Asterozoa. Members are most readily recognized by presence of series of rod-like so-called virgal ossicles extending laterally from each ambulacral ossicle. Five somasteroid genera are recognized and assigned to two families. Four genera are Gondwanan, three of these (Chinianaster, Thoralaster, Villebrunaster) from the Lower Ordovician Tremadocian of France and one (Archegonaster) from the Middle Ordovician upper Darriwilian of the Czech Republic. The fifth genus, Ophioxenikos, is Laurentian from the Floian of Nevada. Catervaparmaster, previously assigned to the Somasteroidea, is left in open nomenclature; absence of virgal-series ossicles favors a lineage apart from the principal asterozoan clades. Asterozoan fossils are readily separated from fossils of other echinoderm groups. The subphylum therefore is thought to be monophyletic, its ancestry unknown. Skeletonized representatives of the four major asterozoan clades first occur through a relatively narrow Early Ordovician stratigraphic interval. Robust skeletons therefore are thought to have evolved after a time of unknown duration including only lineages that were no more than weakly calcified. The French occurrences are from a relatively deep distal shelf setting on soft substrates whereas the Nevada occurrence was in a shallower, active setting. Differences document early ecologic diversification.
Until now, the buccinid genus Chauvetia was considered of European or West African origin, and is still endemic to these areas today. This paper describes the oldest representative of the genus, Chauvetia inopinata nov. sp., from the upper Burdigalian-lower Langhian transition Cantaure Formation of Venezuela. This surprising record suggests a New World tropical origin to the genus and subsequent immigration to the Old World before the earliest known Old World record, which is upper Tortonian. We postulate that this pre-late Tortonian (pre-8.12–7.42 Ma) dispersal of the tropical Gatunian west-Atlantic Chauvetia into the tropical East Atlantic European-West African Province most probably happened during the 10.71–9.36 Ma interval (early—mid Tortonian) during which the Circum-Tropical Current weakened, and the northward Intra-Caribbean Current had started, enhancing the Gulf Stream and the North Atlantic Current. This new data constitutes compelling evidence of a pre-Pliocene eastward dispersal of New World shallow marine organisms across the Atlantic.
Bulk maceration of unconsolidated Potomac Group sediments collected from 12 samples of middle-late Albian and early Cenomanian age on the Elk Neck Peninsula, Maryland, yielded 14 genera and 18 species of megaspores. The identified megaspores have affinities to both heterosporous ferns, e.g., Arcellites and Molaspora, and to heterosporous lycopsids, e.g., Erlansonisporites, Minerisporites, and Paxillitriletes. Morphological variation within species is high, and most morphotypes differ from established taxa in one or more characters. Two new species— Dijkstraisporites praetextus and Verrutriletes diversus—are proposed. The composition of these middle—late Albian and early Cenomanian floras is a mixture of taxa previously recorded from Aptian and Santonian floras in North America. In addition, a fragmentary strobilus of selaginellalean affinity containing a megaspore and microspores is described.
Despite the abundance and diversity of Venericardia bivalves on the U.S. Coastal Plain during the Paleogene, the evolutionary relationships within the genus remain unresolved. The primary objectives of this study were to reconstruct a phylogeny of Venericardia species, identify major clades within the genus, and determine whether groupings within traditional venericard classifications constitute monophyletic taxa. Fifty-one conchological characters were applied to 18 venericard and two outgroup species. Parsimony analysis produced three equally parsimonious trees and robustness was assessed through Bremer support and bootstrap values. The resultant trees indicate that the smooth-ribbed planicostate venericards are monophyletic, whereas the sharp-ribbed alticostate venericards are paraphyletic. Additionally, the original planicostate subtaxon, Venericor, is monophyletic whereas the original alticostate subtaxa, Claibornicardia, Glyptoactis, and Rotundicardia, are nonmonophyletic.
Ed Landing, Jonathan B. Antcliffe, Martin D. Brasier and Adam B. English. 2015. Distinguishing Earth's oldest known bryozoan (Pywackia, late Cambrian) from pennatulacean octocorals (Mesozoic-Recent): Journal of Paleontology, v. 89, p. 292–317
Figure 1 (p. 293) and Figure 2 (p. 294) in the above article were erroneously produced in black and white in the printed version of the issue originally published on 4 June 2015 by Cambridge University Press in the Journal of Paleontology, volume 89, issue 2, pages 293–317. Figures 1 and 2 are produced here in the intended full color for both digital and printed versions of the article.
Andrea Jiménez-Sánchez, Enrique Villas, and Emmanuelle Vennin. New trepostomate bryozoans from the Upper Ordovician of Morocco and the temperature influence on zooid size. Journal of Paleontology 2015; 89:3, p. 385–404. doi: 10.1017/jpa.2015.20.
In the initial publication of the article by Andrea Jiménez-Sánchez, Enrique Villas, and Emmanuelle Vennin published online in the journal on 21 September 2015, the third author's name was incorrect. The author's name is Emmanuelle Vennin (not Enmanuelle Vennin). The editors apologize to the author and readers for this error. The original article has been corrected online to rectify this error.
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