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Three-dimensionally phosphatized, spherical fossils, interpreted as metazoan eggs and embryos on the basis of taphonomic features and cleavage patterns, are reported for the first time from the Cambrian of North America. These microfossils occur with a phosphatized biota of skeletonized fossils, including specimens indicative of the earliest Cambrian Anabarites–Protohertzina Zone in the Wernecke Mountains of eastern Yukon Territory, northwestern Canada. They range in size from 0.25 mm to more than 1.0 mm in diameter and can be referred to two genera, OlivooidesQian, 1977 and ArchaeooidesQian, 1977. The North American discovery extends the biogeographic range of earliest Cambrian eggs and embryos from coeval successions in China and Siberia, suggesting a wide geographic distribution of these taxa, and emphasizes the crucial role of local environmental and taphonomic conditions in preserving this phosphatic window into the record of early animal evolution. In addition to previously reported taxa, the phosphatized biota also include indeterminate spheroids, fused clusters of Protohertzina siciformisMissarzhevsky, 1973, the enigmatic rodlike fossil Zhejiangorhabdion comptumYue and Zhao, 1993, phosphatized fossils, including Paradoxiconus typicalisQian et al., 2001, protoconularid Carinachites sp., and phosphatic tubes assigned to Hyolithellus cf. H. isiticusMissarzhevsky, 1969, cf. Pseudorthotheca sp., and ?Rugatotheca sp.
Caridroit, De Wever, and Dumitrica (1999) promoted stauraxon (Radiolaria) to an order, order Latentifistularia, and De Wever et al. (2001) proposed a classification using family and genus levels. However, the taxonomy of this order in genus level is still problematic because some genera were named according to broken specimens. A radiolarian fauna with a high diversity was collected from the late Changxingian in southern Guanxi, China. These specimens are very well preserved so that they are rare material for roundly describing the characters of some genera. They are identified as 42 species belonging to 16 genera and 5 families. Fifteen new species and one new genus are described, some genera are discussed, and some species are revised.
Two four-shelled species characterized by a pylome-bearing outermost shell—Sphaeropyle robusta and its descendant, Sphaeropyle langii—are selected for morphological study. Both species are morphologically identical to three-shelled Actinomma morphotypes, morphotypes A and B, respectively. Furthermore, the number of pores on half a circumference of the primary cortical shell, the distinguishing feature between Sphaeropyle robusta and Sphaeropyle langii, accounts for the same between Sphaeropyle robusta and morphotype A, and between Sphaeropyle langii and morphotype B. It suggests that the three-shelled morphotypes A and B are juvenile forms of the four-shelled Sphaeropyle robusta and Sphaeropyle langii, respectively. This is strongly supported by the same stratigraphic distributions of each pair. The quantitative analysis of morphological variations in both species also revealed that they have nearly identical morphology, except for the number of pores on half a circumference of the primary cortical shell. In addition, the size range of primary and secondary cortical shells and the range of the number of radial spines increase in Sphaeropyle langii, while the length range of radial spines decrease.
Six new species of fenestrate bryozoans, middle to late Wordian, occur in the Gerster Limestone of northeastern Nevada. These bryozoans are similar to lower Kazanian species described from the Russian Platform. The two species of Wjatkella and Polypora from the Gerster Limestone are much more similar to the Russian species than they are to the two species recently described from the allochthonous late Wordian Mission Argillite of northeastern Washington.
New species described from the Gerster Limestone are Rectifenestella cordiretiformis, Wjatkella hemiseptifera, Kingopora wardlawi, Kingopora inflata, Polypora keyserlingiformis, and Polyporella helgersoni. The presence of only six species of fenestrate bryozoans in nearly 260 m of limestone and siltstone is notable.
Multivariate analytical methods, which have been used effectively in work on scleractinian corals, were applied to tabulate corals. The study involved discrimination and characterization of closely related species of Catenipora from the Selkirk Member, Red River Formation, in Manitoba. Ten morphological characters measured in transverse sections of 37 coralla were tested to perform cluster analyses. Results of correlation analysis and principal component analysis indicated that five of the characters would be suitable: tabularium area, corallite length, corallite width, tabularium length, and tabularium width.
A cluster analysis was performed on the raw data matrix coordinated with 37 coralla by the five selected morphological characters. The characters were standardized to mean 0 and variance 1, and squared Euclidean distances among the coralla were calculated. The unweighted pair-group method using arithmetic average was also employed for clustering the coralla. Four morphospecies were consequently extracted from the dendrogram, which was based on the variation of the five morphological characters, and were confirmed by two types of discriminant analysis. Morphospecies A, B, and D have distinctive ranges in variation of all characters except corallite length. Morphospecies C appears to be an intermediate form, in which the ranges of variation of all five morphological characters partially overlap with those of morphospecies A and/or B.
Another cluster analysis, including eight type specimens of Ordovician species previously reported from Manitoba, was performed on the data matrix coordinated with 45 coralla by the five morphological characters. Based on this analysis and morphological comparisons, morphospecies A–C are identified as C. rubra Sinclair and Bolton inSinclair, 1955, C. foersteiNelson, 1963, and C. robusta (Wilson, 1926) of Nelson, 1963 (=C. cf. robusta herein), respectively. Morphospecies D is equated with both C. agglomeratiformis (Whitfield, 1900) of Nelson, 1963 and C. aequabilis (Teichert, 1937) of Nelson, 1963 (=C. cf. agglomeratiformis herein). The result of cluster analysis based on the five selected morphological characters demonstrates efficiency in distinguishing closely related species of Catenipora from southern Manitoba. The same procedure should also be applicable to other cateniform corals.
Eocene ostracodes are described from the Japanese Islands for the first time. These ostracodes, from the Iojima Group in southwestern Japan, are represented by cosmopolitan and low- to midlatitudinal paleobiogeographic groups as well as an endemic group. Based on the distributions of selected genera, the ostracode fauna of the Iojima Group has tropical to subtropical affinities, affirming links with the Tethys Sea. Six species are described as new: Cytheropteron liue, Eopaijenborchella kamiyai, Eopaijenborchella okinoshimaensis, Ambtonia? matsubarai, Paracypris? kuritai, and Trachyleberis? funatsuensis.
Volutes are widely distributed in the Cenozoic record of Patagonia and Tierra del Fuego, where they are represented by the South American endemic genera AdelomelonDall, 1906, PachycymbiolaIhering, 1907, OdontocymbiolaClench and Turner, 1964, and MiomelonDall, 1907. These taxa have been restricted to the southwestern Atlantic and southeastern Pacific Oceans from Tertiary times to the Recent, and since their earliest record in the ?Middle Eocene–Late Oligocene–earliest Miocene they have evolved adaptations to variations in water depth and temperature. These ecological adaptations were less marked for Adelomelon and Pachycymbiola, which have achieved a similar geographical pattern since the Tertiary, but they were strongly modified in Miomelon. In the Atlantic, Miomelon migrated southwards from the shallow and warm-temperate waters that it typically inhabited during the Tertiary, to deeper, colder waters of the Recent Magellanic Province and Subantarctic region, where it is restricted at present. A detailed discussion of the validity of Tertiary genus ProscaphellaIhering, 1907 herein concludes it to be a synonym of MiomelonDall, 1907. Seven species are redescribed and illustrated: Adelomelon pilsbryi (Ihering), A. cannada (Ihering), A. (Pachycymbiola) ameghinoi Ihering, ?Pachycymbiola feruglioi (Doello Jurado), Miomelon gracilior (Ihering), M. dorbignyana (Philippi), and M. petersoni (Ortmann); and four new ones are described: Miomelon castilloensis, Pachycymbiola chenquensis, P. camachoi, and P. arriolensis.
In central Chiapas (southeastern México) the last occurrence of inoceramid bivalves was recorded in strata of the predominantly terrigenous Ocozocoautla Formation. The inoceramids are associated with foraminifers of the Gansserina gansseri Zone (Late Campanian to Early Maastrichtian). The described species are: Cataceramus? cf. barabini (Morton, 1834), Cataceramus? cf. subcircularis (Meek, 1876), Trochoceramus aff. costaecus (Khalafova, 1966), Trochoceramus nahorianensis (Kociubynskij, 1968), and Trochoceramus tricostatus n. sp. Based on the inoceramid and foraminifer species present, the assemblage is assigned to the Early Maastrichtian. This age is important because at this level most of the typical inoceramids globally disappeared. This is the first report of the genus Trochoceramus in México, which is a good index fossil for the Early Maastrichtian and has a cosmopolitan distribution.
The Lower Ordovician middle Beekmantown Group is a very thin carbonate platform succession on the northern New York Promontory that thickens north into the Ottawa aulacogen near Montréal. The Tribes Hill Formation (Rossodus manitouensis Zone) records the earliest Ordovician (late Skullrockian, late early Tremadocian) eustatic high that submerged Laurentia, and produced the lowest Ordovician sequence along the New York Promontory. These dolostones are succeeded in the Beekmantown, New York, area by late Tulean?–Blackhillsian transgressive systems tract quartz arenites of the lower Fort Cassin Formation (Ward Member). The “Fort Ann Formation” (middle Stairsian, upper Tremadocian) of the southern Lake Champlain lowlands (=Theresa Formation sandstones in the Ottawa graben) is absent at Beekmantown, and moderate Stairsian (late Tremadocian) eustatic rise apparently did not inundate the Beekmantown area after Skullrockian–Stairsian boundary interval offlap. Highstand carbonates of the upper Fort Cassin Formation [Sciota Member = “Spellman Formation” and “Ogdensburg Member” of the “Beauharnois Formation” in the Montréal area; designations abandoned] at Beekmantown yield diverse conodonts seemingly characteristic of the Oepikodus communis–Fahraeusodus marathonensis Zone (new). However, associated trilobites, particularly Carolinites tasmanensis (Etheridge, 1919), show a correlation with the upper Trigonocerca typica (trilobite) Zone of the Utah and the overlying Reutterodus andinus (conodont) Zone. This abrupt early Blackhillsian lithofacies change features the appearance of chitinozoans and conodonts known from marginal successions, and records the Laignet Point highstand (new). This highstand is recognized across Laurentia on the west Newfoundland and southern Midcontinent platforms. It is recorded on the east Laurentian continental slope by lower Oepikodus evae Zone dysoxic black mudstone in the Taconian allochthons. Taxonomic re-evaluations include UlrichodinaBranson and Mehl, 1933, with its genotype species U. abnormalis (Branson and Mehl, 1933) emend., as the senior synonym of ColaptoconusKennedy, 1994; EucharodusKennedy, 1980; and GlyptoconusKennedy, 1980. Paraserratognathus An inAn et al., 1983, emend. is the senior synonym of WandeliaSmith, 1991 and StultodontusJi and Barnes, 1994. TropodusKennedy, 1980 is the senior synonym of ChionoconusSmith, 1991. The trilobite fauna of the Sciota Member includes species of Isoteloides, Benthamaspis, Acidiphorus and Carolinites
Two new species of scutelluine styginid trilobites are described from Frasnian strata in the Virgin Hills Formation in the Canning Basin of Western Australia. They are placed in the genus Telopeltis n. gen., reflecting the fact that their final occurrence in the late Frasnian, up to the latest Frasnian Kellwasser extinction event, is the last known record of scutelluine trilobites. As such, it also represents the youngest record of the order Corynexochida. The two species, Telopeltis woodwardi n. sp. and Telopeltis microphthalmus n. sp., are unlike most other scutelluines in possessing extremely vaulted pygidia and showing trends to eye reduction. Such eye reduction is a common feature of late Frasnian trilobites. The characteristic morphological features of this small genus are indicative of evolution of this last scutelluine by paedomorphosis.
A new fossil Ictiobus species is described, based on an abundant collection of well-preserved isolated bones found in lacustrine deposits of Pliocene (Blancan) age near Tula de Allende, state of Hidalgo, central Mexico. This fossil Ictiobus species shows the diagnostic character of the genus. In the palatine bone the ethmoid process is longer than the premaxillary process. Suspensorial pleural ribs with trapezoidal shape and a dentary bone with extremely short and wide gnathic ramus are the characters that support the creation of this new Ictiobus species. The fossil record of Ictiobus, the first known in Mexico, extends the paleogeographical distribution known of this genus, which had been previously restricted to the USA.
A new eutherian mammal of uncertain taxonomic position is described on the basis of well-preserved dental and gnathic specimens collected from localities in the Paleocene Paskapoo Formation of Alberta, Canada. Horolodectes sunae new genus and species is represented by seven incomplete maxillae, eleven incomplete dentaries, and numerous isolated teeth, together preserving nearly all of the postcanine dentition. The unusual dentition of Horolodectes n. gen. consists of trenchant, posteriorly leaning premolars in combination with comparatively primitive molars, suggestive of a masticatory cycle that consisted primarily of shearing and, to a lesser degree, horizontal grinding. Included among the specimens of Horolodectes is an incomplete dentary of an immature individual, with the teeth having been in various stages of eruption at the time of death. Although the dentition of Horolodectes broadly resembles that of apheliscine hyopsodontids, pentacodontine pantolestids, and “ungulatomorphs” among eutherian mammals, significant differences in the coronal structure of the teeth prevent unequivocal referral of Horolodectes to any of these groups, or to any known eutherian order.
Problematic phosphatic elements are reported for the first time from Bohemia, Czech Republic, and are attributed to Eurytholia bohemica n. sp. Similar mineralized elements, interpreted as sclerites, were known only in a very narrow interval from Middle-Late Ordovician beds bordering the Iapetus Ocean. This new report comes from the Silurian and Early Devonian and provides a significant range extension for these Problematica as well as an enlargement of their geographic extent. Comments open new perspectives in the interpretation of these elements.
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