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A single bed at the base of the Jordan Sandstone in a road cut at Arcadia, Wisconsin, yielded an undescribed Late Sunwaptan (Saukia Zone) trilobite fauna that includes at least four species from the families Dikelocephalidae Miller, 1889 and Eurekiidae Hupe, 1953. Arcadiaspis bispinata n. gen. and sp. is a distinctive eurekiid that is characterized by paired occipital and thoracic axial spines, long genal spines, and a nonspinose pygidial margin. Other genera present are the dikelocephalids, Dikelocephalus Owen, 1852 and Calvinella Walcott, 1914, and the eurekiid, Eurekia Walcott, 1916. Type material of Calvinella spiniger (Hall, 1863) is illustrated photographically for the first time. A new eurekiid species, Corbinia burkhalteri from the Fort Sill Formation, Oklahoma, is also described.

A new lyssacinosan hexactinellid, Rossella bromleyi n. sp., is described from the Upper Cretaceous of Arnager Pynt, Bornholm (Denmark). The sponge shows a cup-shaped form with a broad, moderately dense root tuft, which contains three- and four-rayed orthotropal anchors characteristic for Rossella. The skeleton is composed of bundles of diactines, hexactines of two orders, and pentactines. Diactine bundles are mainly in the growth direction or diagonal to it. Prostalia lateralia are pentactines with the paratangential rays protruding beyond the outer surface of the sponge body. Hypodermalia are absent.

A new albulid fish, Phosphonatator oxyrhynchus, based on a single large neurocranium, is described from the deposits of the Ouled Abdoun phosphatic basin, Morocco. The matrix of the fossil contains an elasmobranch assemblage indicating a Danian age (with some redeposited Maastrichtian elements). P. oxyrhynchus is characterized notably by its elongated snout and by a reduced patch of teeth on the parasphenoid. Up to now, fossil fishes from the Ouled Abdoun phosphatic basin were mainly known by isolated remains, and the recovery of this specimen should be ranked equal to the recent discovery of important, very well-preserved new material of vertebrates in the Sidi Daoui area.

A new species of multituberculate mammal, Hainina pyrenaica n. sp. is described from Fontllonga-3 (Tremp Basin, Southern Pyrenees, Spain), correlated to the later part of chron C29r just above the K/T boundary. This taxon represents the earliest European Tertiary mammal recovered so far, and is related to other Hainina species from the European Paleocene. A revision of the species of Hainina allows recognition of a new species, H. vianeyae n. sp. from the Late Paleocene of Cernay (France). The genus is included in the family Kogaionidae Radulescu and Samson, 1996 from the Late Cretaceous of Romania on the basis of unique dental characters. The Kogaionidae had a peculiar masticatory system with a large, blade-like lower p4, similar to that of advanced Ptilodontoidea, but occluding against two small upper premolars, interpreted as P4 and P5, instead of a large upper P4. The endemic European Kogaionidae derive from an Early Cretaceous group with five premolars, and evolved during the Late Cretaceous and Paleocene. The genus Hainina represents a European multituberculate family that survived the K/T boundary mass extinction event.

Three new species of the shallow-marine, warm-water bivalve Plicatula are reported from the upper Paleocene Santa Susana Formation of southern California. Plicatula simiensis new species is from the middle part of the formation on the south side of Simi Valley and occurs as a displaced specimen in deep-marine turbidites. Plicatula lapidicina new species and P. trailerensis new species are both from coralline-algal-rich muddy siltstone just beneath a nearshore, coralline-algal limestone interval in the upper part of the formation in the Santa Ynez Canyon area, east-central Santa Monica Mountains. These three new species represent the first late Paleocene records of genus Plicatula on the west coast of North America and the first Paleocene records of this genus in southern California.

Recently collected specimens of Catopsalis fissidens from the Torrejonian interval of the Nacimiento Formation in the San Juan Basin, New Mexico significantly augment knowledge of the morphology and dental variability of the species. This new knowledge suggests C. foliatus Cope, 1882 (=C. johnstoni Fox, 1989) is a valid Puercan species and that C. fissidens Cope, 1884a is a subjective senior synonym of C. utahensis Gazin, 1939. This latter synonymy further increases taxa shared between the Dragon Canyon local fauna of Utah and the Torrejonian fauna of the San Juan Basin, thus supporting previous inclusion of the Dragonian land-mammal 'age' in the Torrejonian.

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.

There has been some confusion regarding the index nanofossil specie Discoaster diastypus, despite its frequent use in biostratigraphy. In light of this factor, the species concept should be clarified to make it more precise for use in biostratigraphy. In this regard, the sample used to describe the species in 1961 is reexamined. Its size is measured, its rays are counted and it is photographed in both plan and side views.

Three species of mollusks and one annelid are described from the Paleocene upper mudstone member of the Potrerillos Formation (La Popa Basin), and from the upper part of the Rancho Nuevo Formation (Parras Basin). The species described include a gastropod, a bivalve, a nautiloid and a serpulid worm, which are formally reported for first time as Paleocene fauna of the Difunta Group in northeastern Mexico. The nautiloid species provides the basis for correlation between the two sedimentary basins of the Difunta Group, as it is reported for Paleocene layers of the two formations studied. Shoreface and tidal-flat depositional environments are inferred for the Paleocene rocks of the Difunta Group.

New Mollusca from the shallow marine, highly fossiliferous Wangaloa Formation of southeastern Otago, South Island, New Zealand, are described. This paper reports three new species and one new genus: Leionucula palaioanaxea n. sp. of the Nuculidae, Pyropsis zinsmeisteri n. sp. of the Tudiclidae, and Wangacteon grebneffi n. gen. and sp. of the Acteonidae. These taxa represent new records in New Zealand of apparently endemic taxa. The molluscan fauna of the Wangaloa Formation is important in the understanding of Paleogene biogeography of the Southern Hemisphere and changes in faunal composition of the Cretaceous-Tertiary Gondwana Realm. Genus- and species-level endemism of the 'Wangaloan' fauna is marked and is probably a reflection of 'greater New Zealand' 's geographic and genetic isolation during the Paleocene. Although deposits containing early Paleogene Mollusca are generally rare in the Southern Hemisphere, comparisons of known Gondwana molluscan taxa and those of similar age in the Northern Hemisphere indicate that the Mollusca of the Wangaloa Formation have Early Paleocene affinities. Microfossil evidence, in addition, supports an Early Paleocene age for the fauna. However, an uppermost Cretaceous age is indicated for the basal part of the Wangaloa Formation stratigraphically below the shell beds, but the K-T boundary has yet to be located.

Alcidedorbignya inopinata Muizon and Marshall is a primitive pantodont from the Early Paleocene of T Department of Cochabamba, in the 'Cordillera Oriental' of south-central Bolivia. It is known by almo dentitions, which are described in detail. The occurrence of abundant juvenile specimens allows a st molars of Alcidedorbignya inopinata are primitive for a pantodont but they show the characteristics which is the presence of a V-shaped ectoloph of P3-4. However, the paracone and the metacone of A. i their bases, a feature absent in the Bemalambdidae and Harpyodus, which have connate to semi-connate Because of this character, A. inopinata, although the oldest, is not the most primitive pantodont. H bemalambdids and Harpyodus, does not have a mesostyle on M1-2/ or a strong V-shaped centrocrista, wh other pantodonts. For this reason, Alcidedorbignya inopinata is removed from the Pantolambdidae (whi referred to the new monotypic family Alcidedorbignyidae. The family Wangliidae Van Valen, 1988, is n genus Wanglia is regarded as a junior synonym of Harpyodus; the latter includes the two species H. e of pantodont origins leads to the conclusion that didelphodontines constitute the best potential sis could be found to substantiate this hypothesis. Alcidedorbignya inopinata is the first pantodont kno continent and, being the oldest, it raises a discussion on the paleobiogeographic history of the gro, The pantodont Alcidedorbignya inopinata from the early Paleocene of Tiupampa, Department of Cochabamba in Bolivia is described. The mammal is described from about 200 dental elements and about 125 partial jaws. Furthermore, the abundant juvenile specimens permitted the study of tooth replacement. The findings are discussed in terms of the phylogenetic and paleobiogeographic implications of the occurrence of the oldest pantodont in a southern continent.

Siliceous sterraster microscleres of the choristid demosponge, Geodia Lamarck, 1815, occur in outcro Porters Creek Formation (Paleocene) near Moscow Landing on the Tombigbee River in southeastern Sumte This is the first report of that sponge from the Cretaceous-Tertiary of the Gulf Coastal Plain. The been converted to clinoptilolite, a Na-K-Ca zeolite., Tiny acid-resistant siliceous spheres discovered in the Paleocene Porters Creek Formation were analyzed and identified to be the microspicules of the demosponge Geodia. The microspicules were previously mistaken for the ultimate chambers of Subbotina trinidadensis. The discovery is significant because it is the first report of the occurrence of Geodia in the Mesozoic/Cenozoic strata in the Gulf or Atlantic Coastal Plain regions.

Dinosaur teeth from Paleocene channel fills have been interpreted as indicating dinosaur survival into the Paleocene. However, enormous potential for reworking exists because these records are restricted to large channel fills that are deeply incised into Cretaceous strata. Identification of reworked fossils is usually equivocal. This problem is illustrated by the Black Spring Coulee channel fill, a dinosaur-bearing Paleocene deposit in the upper Hell Creek Formation of eastern Montana. In this example, the reworked nature of well-preserved dinosaur bones is apparent only after detailed sedimentological and palynological analysis. Because of the potential for reworking, donosaur remains derived from Paleocene fluvial deposits should not be assigned a Paleocene age unless they (1) are found in floodplain deposits, (2) are articulated, (3) are in channels that do not incise Cretaceous strata, or (4) are demonstrably reworked from Paleocene deposits. To date, reports of 'Paleocene' dinosaurs do not fulfill any of these criteria. Thus, the proposal that dinosaurs persisted into the Paleocene remains unsubstantiated.

Plesiadapiformes has long been considered to be an archaic group of Primates. Discovery of a paromomyid plesiadapiform skull and independent analysis of referred postcrania have led investigators to conclude that Plesiadapiformes shares a closer relationship to extant flying lemurs (Dermoptera) than to Primates (= Euprimates of Hoffstetter [1977] Bull Mem Soc Anthropol Paris Ser 13 4:327-346). Despite challenges to this interpretation, the plesiadapiform-dermopteran relationship has gained currency in recent years. Here we show that newly discovered crania of Ignacius graybullianus, preserving previously undocumented portions of the ear, are more similar to primates than to dermopterans. New specimens confirm that paromomyids lacked the petrosal bulla of primates. However, these new specimens also demonstrate that paromomyids likely had: 1) a small promontorial branch of the internal carotid artery; 2) a lateral route for the internal carotid nerves crossing the promontorium; and 3) a ring-like ectotympanic with an annular bridge. This pattern is similar to primitive primates and fundamentally different from dermopterans, which have: 1) no internal carotid artery; 2) internal carotid nerves that take a more medial route; and 3) no annular bridge. Recognition of some primate-like traits, documented here by new evidence, indicates that Paromomyidae is likely to be more closely related to other Paleogene Plesiadapiformes and Eocene Primates than to extant Dermoptera. In view of these findings, a link between paromomyids and extant dermopterans ('Eudermoptera') is not convincingly supported by a single characteristic of the basicranium. Am J Phys Anthropol 116:184-198, 2001. KEY WORDS basicranium; Dermoptera; Paromomyidae; Plesiadapiformes; primate origins; Wyoming

H.-D. Sues contests the identification of Chronoperates as a Paleocene therapsid reptile, and implies that it must be a mammal instead. But Sues does not specify which of the several competing definitions of mammals he has in mind, so it is not clear by what criteria he classifies Chronoperates as a mammal. Also, he dismisses the therapsid-like dental features as artefacts of preservation, not legitimate anatomical features. But since he has never examined the specimen, this reflects only his expectation. The evidence supports identification of Chronoperates as a therapsid.

The anatomical evidence relating to the fossil Chronoperates paradoxus discounts the claim that this specimen is a 'mammal-like reptile' or nonmammalian synapsids whose discovery in the Paleocene of Alberta, CN, shows that such animals were alive 100,000 years later than is commonly thought. A new anatomical examination of the fossil's postcanines, pseudoprismatic enamel, alleged postdentary bones and masseteric fossa casts doubt on the classification of this species as a nonmammalian cynodont.

The discovery of fossils from a therapsid or mammal-like reptile in the upper Paleocene Paskapoo Formation in Alberta, Canada, extends the known existence of these animals to 100 million years later than was previously thought. Therapsids are believed to be the evolutionary link between reptiles and mammals. Fox and colleagues, who found the fossils, call the new animal Chronoperates paradoxus and classify it as a therapsid based on several anatomical features such as the tooth enamel's microstructure. However, this classification will remain tentative until further evidence proves it.