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Since 1908, the peculiar North American primate PicrodusDouglass, 1908 (Picrodontidae; Plesiadapiformes) has been thought to contain only a single species, P. silberlingiDouglass, 1908, of late Paleocene age. However, new collections from the Paskapoo Formation, Alberta, Canada, reveal that instead a rich complex of Picrodus species lived during the Paleocene. Three of these, Picrodus calgariensis, P. canpacius, and P. lepidus, are described herein as new. Others, represented by more fragmentary specimens from Canada and the United States, are included in this paper, but are not named. P. calgariensis, from Who Nose? (late Torrejonian), Calgary, is the most primitive known species of Picrodus, having molars with little crenulation of the enamel. P. canpacius, from Cochrane 2 (earliest Tiffanian), northwest of Calgary, most resembles P. silberlingi sensu stricto, but differs in P4 structure, denser enamel crenulation, and weaker molar cusps. P. lepidus, from DW-2 (middle Tiffanian), near Red Deer, is the most advanced, having, for example, a two-rooted P4, tiny p3, and single-rooted p4. At least two of these species also occur in the United States, documented by fossils referred to P. silberlingi by previous workers. Dental evolution within Picrodus seems marked by several trends, including increase in size of i1, simplification of P4, reduction of molar cusps and crests, enlargement of the horizontal occlusal surfaces of the molars, and greater crenulation of enamel. From present knowledge, Zanycteris paleocenusMatthew, 1917 is dentally more primitive than Picrodus, DraconodusTomida, 1982 is a valid genus, and picrodontids probably originated from “purgatoriid-grade” plesiadapiforms in earliest Paleocene time.
The new dragonfly family Austroperilestidae n. fam. based on Austroperilestes hunco n. gen. and sp. is erected from early Eocene of Patagonia (Argentina). Its phylogenetic relationships within the Zygoptera (sensu Bechly, 1996) are discussed. The new family seems to be related to Perilestidae, with a Neotropical and Afrotropical recent distribution.
Harpactocarcinus punctulatus istriensisBachmayer and Nosan, 1959 is elevated to species level. Analysis of the larger foraminiferans associated with specimens of H. istriensis suggests a habitat preference for off-shore, clear, shelf environments below fair-weather wave base and an age of early to middle Lutetian (Eocene). A review of the paleoenvironmental indicators for nearly all species within the genera referred to the Zanthopsidae Via, 1959 suggests that all exhibit similar habitat preferences. Description of the paleoenvironmental preference for an entire extinct decapod family has not before been possible.
A newly discovered Late Ordovician (early Ashgill) brachiopod assemblage from the Linhsiang Formation in the middle part of the Yangtze Platform, South China, bridges the paleobiogeographical gap between the early Ashgill Foliomena-bearing associations known previously from the upper and the lower parts of the Yangtze Platform. Characterized by minute shells in calcareous to siliciclastic mudstones, the fauna contains 13 brachiopod genera, of which two plectambonitoids are new: Hadroskolos and Jingshanella. Cluster and principal component analyses, based on 29 global occurrences of the Foliomena fauna in Laurentia, Avalonia, Kazakhstan, Baltica, Sardinia, Bohemia, Sibumasu, North China, and South China, revealed broad trends of spatial and temporal faunal differentiation in terms of taxonomic compositions. The analyses demonstrate for the first time that early Foliomena-bearing associations of Caradoc age occupied primarily deepwater (distal shelf) environments with a siliciclastic or calcareous mud substrate. The fauna attained its widest paleogeographical distribution and paleoecological range (midshelf to shelf margin settings) during the early Ashgill.
The Khabarovsk Complex, a Jurassic accretionary complex distributed in and around the Khabarovsk city area, Far East Russia, comprises mélange and schist facies. From the review of previous studies including Russian papers, the lithology and age of the constituent rocks of the mélange facies can be summarized as follows: Upper Paleozoic basic volcanic rocks, mainly pillow lava, and altered gabbro, Upper Carboniferous to Upper Permian fusulinoidean-bearing limestone associated with tuff, Lower and Middle Jurassic siliceous mudstone, Upper Jurassic tuffaceous mudstone, uppermost Jurassic carbonate concretions embedded in mudstone, and age-unknown sandstone. Newly found sequences of limestone-chert and of basalt-chert in the mélange facies crop out along the Amur River in the Khabarovsk city area. A chert sample of the limestone-chert sequence contains Albaillella aff. asymmetrica and Pseudoalbaillella aff. lomentaria, and a chert sample of the basalt-chert sequence includes Follicucullus monacanthus, Follicucullus porrectus, and Pseudoalbaillella cf. yanaharaensis. The radiolarian assemblages from the limestone-chert and basalt-chert sequences have a maximum age of middle Early Permian and late Middle Permian, respectively, overlapping the time of deposition of the fusulinoidean-bearing limestone. The co-occurrence of chert and limestone indicates that the fusulinoidean-bearing limestone was formed on a basaltic topographic high in a pelagic ocean whereas the radiolarians accumulated in a deeper part. Limestone debris occasionally flowed into the depositional site of the radiolarian chert. Although the Khabarovsk Complex was simply considered as a northern extension of the Mino–Tamba Belt of the Inner Zone of southwest Japan, we propose a new correlation based on the lithologic associations. The mélange facies of the Khabarovsk Complex is correlative with one of the Kasugano, Funabuseyama, Nabi, and Yabuhara Formations in the Mino–Tamba Belt, whereas the schist facies is correlative with the Hikami Formation of the Ultra–Tamba Belt.
The recovery of well-preserved silicified larvae from the early Tournaisian of Montagne Noire, southern France, allows the first description of the early ontogeny of proetoid trilobites, survivors of the end-Devonian Hangenberg extinction event. The fauna comprises various taxa that can only partly and tentatively be assigned to the genera Liobolina, Diacoryphe, and Pedinocoryphe without specific attribution. The close resemblance of these larvae to previously described proetoid larvae from the Ordovician and Devonian emphasizes the ontogenetic homogeneity of this superfamily. Moreover, it supports the view that the Proetida is composed of two clades: the Aulacopleuroidea/Bathyuroidea group and the Proetoidea. The Carboniferous anaprotaspides exhibit an unusually wide size-range that may provide evidence of the acquisition of an extended planktonic period in the early ontogeny of at least some Carboniferous proetoids. This change in the ontogenetic strategy may have enabled proetoid trilobites to survive during the end-Devonian biocrises.
The Mississippian ammonoids Kazakhstania mangeri new species, Muensteroceras cf. oweni (Hall, 1860), and Masonoceras kentuckienseWork and Manger, 2002 occur near the base of the Nancy Member of the Borden Formation in northeastern Kentucky. Associated conodonts indicate an early Osagean [Fern Glen or lower Burlington (Dolbee Creek Member) equivalent] age corresponding to the lower Ivorian Stage of the Belgian upper Tournaisian succession.
The following differences were found between the members of the cornulitids, Cornulites and Conchicolites. Both genera have egg-shaped embryonic shells, which presumably calcified after the settling of larva to the substrate, but the embryonic shells in Cornulites are larger than in Conchicolites. Cornulites has a regularly foliated shell ultrastructure and pseudopuncta, whereas the shell ultrastructure in Conchicolites is prismatic. In Cornulites the outer part of the shell contains numerous vesicular cavities that were never observed to cross the interspaces of the surface annulae, indicating cyclic shell secretion. In several species the vesicles are internally coated by calcitic lamellae that are oriented subparallel to the shell surface. In Conchicolites the vesicular shell structure is absent and the calcitic prisms are deposited at the shell aperture more or less at right angles to the longitudinal shell axis. The function of the surface annulae in Cornulites and transverse ridges in Conchicolites may have been to strengthen the shell wall and protect it against longitudinally developing cracks. Vesicular structure in Cornulites seems to have provided a stronger shell for less material and smaller cost of energy. Differences between Cornulites and Conchicolites indicate that the two taxa were probably unrelated and that cornulitids may be a polyphyletic taxon. Cornulites shares the most characters with the lophoporates and tentaculitids. Biological affinities of Conchicolites are controversial, and its morphologic features need further revision to affiliate this group with certainty to any extant animal phylum.
Two new flat-backed archipolypodan millipede taxa, Orsadesmus rubecollus n. gen. and sp. and Zanclodesmus willetti n. gen. and sp., are described from the Upper Devonian of Clinton County, Pennsylvania, and Miguasha, Québec, respectively. These new taxa are placed in the new family Zanclodesmidae within the order Archidesmida. Archidesmida have previously only been described from the United Kingdom, and their presence in North America confirms a geographic continuum in the millipede fauna across the Old Red Sandstone Continent during the Devonian.
A new genus and three new species of echinoids occur in several horizons of an echinoderm Lagerstätten in the Winchell Formation of north-central Texas. This occurrence is dominated by several thousand specimens of Archaeocidaris brownwoodensis new species, a medium-sized archaeocidarid with long, triangular, ornate spines. Another rare archaeocidarid, Archaeocidaris apheles n. sp., is a small, smooth-spined species. The second most abundant echinoid is Elliptechinus kiwiaster n. gen. and sp., an unusual elliptical lepidocentrid, which extends the range of lepidocentrids into the Pennsylvanian (Late Carboniferous). A fourth echinoid, an unidentified echinocystitid, is known from one disarticulated specimen and appears to be mostly composed of ambulacral plates of varying shape and size.
Remains of Halisaurus sternbergi (Wiman, 1920) from the latest Early Campanian (sensu germanico) of the Kristianstad Basin, southern Sweden, represent the first record of this species outside of the USA. The material comprises numerous marginal tooth-crowns, a premaxilla, an incomplete pterygoid, and vertebrae. The Kristianstad Basin population of H. sternbergi was probably derived from individuals that migrated from the Mississippi Embayment in North America sometime during the Early Campanian. Even though H. sternbergi thrived in great numbers in the coastal waters of the southern part of the Baltic Shield during the latest Early Campanian, the population appears to have been short-lived. Available data indicate that H. sternbergi, along with several other species of mosasaurs, vanished from the region following an intercontinental mosasaur extinction event, or a series of events, near the Early/Late Campanian boundary.
Disrupted conodont bedding plane assemblages are described from two laterally equivalent mudstone core samples of the Lower Mississippian upper shale member of the Bakken Formation in the subsurface of southeastern Alberta and southwestern Saskatchewan. The core bedding plane conodont assemblage representing the bispathodid biofacies from southeastern Alberta (Locality 1) shows little evidence of winnowing. Thus, this assemblage, along with collections of discrete conodont elements, is a potential source of data for reconstructing paleoecology and taphonomy as well as for testing apparatus reconstructions. The assemblage representing the siphonodellid biofacies from the southwestern Saskatchewan core (Locality 2) shows evidence of a greater degree of breakage and winnowing of elements, making it less suitable as a source of data. Postmortem compaction of mudstones and processing methods also affect the preservation of the conodont elements, due to breakage along lines of fracture in the elements. An apparatus reconstruction is proposed for Prioniodina aff. P. curvidens.