Several polyplacophoran plates are preserved as external molds in the Lower Permian Rio Genoa Formation, Chubut Province, Argentina. These are the first reported Permian polyplacophorans from South America. The new genus and species Asketochiton chubutensis is described based on this material.

A silicified fauna from the early Permian Coyote Butte Limestone within the Grindstone terrane of central Oregon contains a diverse fauna including five polyplacophorans, one rostroconch, and one problematic taxa. New taxa include Gryphochiton planoplata new species, Arcochiton soccus new species, Homeochiton triangularis new genus and species, Arceodomus sphairikos new species, and Diadeloplax apiculatus new species.

Trilobites assigned to 25 genera and 39 species are reported from the Crepicephalus Zone (Marjuman Stage) and Aphelaspis Zone (Steptoean Stage) in the lower part of the Deadwood Formation in the Black Hills of South Dakota. Six taxa are left in open nomenclature, and one new species, Glaphyraspis newtoni, is described.

Analysis of the lithologies for this interval from the best exposed measured sections on a southeast-northwest transect reveal a nearshore, shallow subtidal, siliciclastic dominated environment to the southeast, succeeded offshore by a shallow subtidal to lowest intertidal carbonate shoal environment, and then a transitional shaly limestone interval into a more shaly distal intrashelf basin to the northwest.

Specimens of species of Coosia, Crepicephalus, Tricrepicephalus, Kingstonia, Pseudagnostina, and Coosina comprise more than 75 percent of the fauna of the Crepicephalus Zone. Coosina ariston, Crepicephalus snowyensis, Tricrepicephalus tripunctatus, Arcuolimbus convexus, and some species of Blountia had a strong preference for the shallow-water siliciclastic facies present in the southeastern sections closest to the paleoshoreline. Crepicephalus rectus, Tricrepicephalus coria, Agnostogonus, cf. A. incognitus and the genera Coosella and Uncaspis preferred the farther offshore, deeper-water, shaly intershelf basin located in the northern Black Hills. Trilobites from the Crepicephalus Zone are used to correlate the lower part of the Deadwood Formation with coeval strata elsewhere in North America.

A new genus and species of clawed lobster, Jagtia kunradensis, is described from the Upper Cretaceous (Upper Maastrichtian) Kunrade Limestone facies of the Maastricht Formation, The Netherlands. Three nephropid lobster genera and at least three species (Oncopareia bredai Bosquet, 1854, sensu Tshudy, 1993, Oncopareia sp. Tshudy, 1993, Hoploparia beyrichi Schlüter, 1862, and Jagtia kunradensis) have now been collected from limestones of the Maastrichtian type area (southeastern Netherlands and northeastern Belgium). Cladistic methods were employed in re-evaluating the phylogenetic relationships of the nephropid lobsters, including Jagtia. These analyses indicate that Jagtia is part of a clade that includes the recent Thymops and Thymopsis. The new genus is the first fossil form to be closely allied with these deep-water genera.

Analysis of dorsal carapace characters of fossil and extant genera of the Calappidae sensu lato supports Bellwood's (1996) assignment of the group into four families based upon phylogenetic analysis, which was also supported by previous larval and morphologic studies. The Calappidae sensu stricto, Matutidae, and Hepatidae, recognized by Bellwood (1996), embrace both fossil and extant genera. The Orithyiidae is known from a single extant genus. Additionally, the Necrocarcininae Förster, known only from extinct genera, is elevated to family status. New taxa include Mursia aspina and Eriosachila rossi. Zanthopsis rathbunae Kooser and Orr, 1973, is here referred to Eriosachila orri, n. comb. and nomen novum. Emended descriptions are given for Mursia yaquinensis Rathbun, 1926, and Necrocarcinus hannae Rathbun, 1926. Biogeographic analysis indicates that each family has a distinct origination and dispersal history independent of the other families. Ecologic information for each group suggests that climatic preferences for the extant families have either remained relatively stable since the appearance of each family in the Tertiary or were broader in the past.

The Mississippian blastoid Pentremites Say, 1820, has three different types of summit structures. Type 1 summits are characterized by long slender plates and are present in upper Meramecian and lower-upper Chesterian beds occurring from Iowa to Alabama. Type 2 summits consist of a massive pyramidal summit composed of large toothlike plates. They occur in lower and middle Chesterian deposits located from Illinois to Kentucky. Type 3 summit structures differ greatly from Types 1 and 2, generally consisting of six to seven rectangular plates arched over each side of individual spiracles. They have been found only in middle Chesterian sediments of Kentucky. In all three types of summit structures, the plates covering the anal spiracle are the most numerous and have a specialized arrangement of plates. Some anal spiracles are covered by alternating small spikelike plates, while others display a distinct anal sac or moundlike structure consisting of many small polygonal plates. Type 2 summits have many similarities with Type 1, and may have been derived from it. Type 3 summits, however, are radically different in type of plates and in their arrangement; their origin is not known. Type 3 summits are very common in the middle Chesterian.

Despite its atypical thecal plate pattern, Lagynocystis pyramidalis (Jaekel, 1918) (Middle Ordovician, Northern Gondwanaland) is composed of normally positioned marginal plates on the left side of the theca, whereas those on the right side are shortened or missing in comparison with marginal plates of other ankyroids. The only somatic on the lower thecal surface is the CS plate. The abnormally long distal aulacophore, reduced theca, and internal ctenoid organ are interpreted as adaptations to deep water, dysaerobic environmental conditions. Ctenoid organ morphology is re-evaluated and is interpreted to have both feeding and respiratory functions. Loss of plates relative to a presumed ancestor similar to Barrandeocarpus has resulted in torsion that places somatic platelets, originally on the superior face, onto the inferior face and in contact with both CS and M'3 plates.

Sand dollars in the Monophorasteridae Lahille, 1896, form an important part of the South American Cenozoic echinoid fauna. Re-examination of type and other material adds significantly to our knowledge of the morphology and taxonomy of the family, and shows that besides Monophoraster darwini (Desor, 1847), M. duboisi (Cotteau, 1884), Amplaster coloniensis Martínez, 1984, and A. alatus Rossi de Garcia and Levy, 1989, there is a new species, A. ellipticus. We also show that Karlaster Marchesini Santos, 1958, is not a monophorasterid as once thought. A phylogenetic analysis of 24 characters assessed from all species of Monophoraster Lambert and Thiéry, 1921, and Amplaster Martínez, 1984, along with genera of the Mellitidae Stefanini, 1912, produced a single most parsimonious tree. The analysis demonstrates monophyly of mellitids and monophorasterids, and that Iheringiella Berg, 1898, should be excluded from the latter. Although both Monophoraster Lambert and Thiéry, 1921, and Amplaster Martínez, 1984, retain many features of an ancestor in common with the Mellitidae Stefanini, 1912, they also exhibit bizarre morphologies quite different from those of mellitids. The study has also resulted in a clearer picture of the biogeography and biostratigraphy of the Monophorasteridae, and their great significance in the evolution of lunulate sand dollars in the Americas.

Late Ordovician rocks of the Qilang and Yingan formations from the Kalpin area in the Tarim region of western Xinjiang, China (Tarim palaeoplate) contain a moderately diverse graptolite fauna. The fauna from the Qilang Formation contains Corynoides calicularis Nicholson, 1867; Dicranograptus clingani resicis Williams and Bruton, 1983; Lasiograptus costatus Lapworth, 1873; Pseudoclimacograptus scharenbergi (Lapworth, 1876); and Glossograptus sp. among other species. This assemblage most likely corresponds to the upper Climacograptus (Climacograptus) bicornis Zone? to lower C. (Diplacanthograptus) lanceolatus Zone of Australia. The Qilang Formation also yields the new taxon, Amplexograptus maxwelli spinousus new subspecies. The overlying Yingan Formation yields a more diverse assemblage that includes Climacograptus (Diplacanthograptus) spiniferus Ruedemann,1912; C. (D.) lanceolatus VandenBerg, 1990; Orthograptus quadrimucronatus (Hall, 1865); Amplexograptus praetypicalis Riva,1987; Dicellograptus pumilus Lapworth,1876; and D. morrisi Hopkinson, 1871. This assemblage most likely corresponds to the Corynoides americanus Zone through the C. (D.) spiniferus Zone of eastern Laurentia, or to the D. clingani Zone of Scotland and central Newfoundland. The presence of a C. (D.) lanceolatus and C. (D.) spiniferus succession in the Yingan Formation also suggests correlation with the Eastonian 1 and 2 of Australasia. The Yingan Formation faunas represent an offshore Pacific Province assemblage dominated by cosmopolitan epipelagic species. The fauna is most similar, both in terms of species composition and relative abundance patterns, to those of the Appalachian Basin. The Yingan faunas differ from the latter in the absence of Laurentian endemic species (except for Amplexograptus praetypicalis), and in the common occurrence of dicellograptids.

Recent paleontological fieldwork in the Upper Devonian Catskill Formation at Red Hill in Clinton County, Pennsylvania, USA, has produced a diverse assemblage of vertebrate fossils including early tetrapods. The tetrapod Hynerpeton bassetti was described from the site in 1994 and a recently recognized partial lower jaw of that taxon is described here. Additionally, this paper describes a new Late Devonian tetrapod, Densignathus rowei new genus and species, based on a well-preserved lower jaw. This new taxon is characterized by dramatic widening of the jaw anterior of the adductor fossa, a pronounced twist in the orientation of ventral margin of the jaw, an uninterrupted exposure of Meckelian bone on the mesial surface, and weakly-developed radiating ornament on the lateral surface of the infradentaries. Although phylogenetic resolution within stem tetrapods is lacking, Densignathus rowei, n. gen. and sp., informs several topics including the sequence of character acquisition in the lower jaw, morphological diversity, and paleoecology of the earliest tetrapods.

A new specimen of the basal mosasaur Halisaurus platyspondylus from the Severn Formation of Prince Georges County, Maryland (Upper Cretaceous: middle Maastrichtian) represents the most complete partial skeleton of this uncommon taxon to be described to date. The characteristic dorsoventral compression of the vertebral centrum is most pronounced in the anterior trunk vertebrae, and the centra of the posterior trunk vertebrae exhibit proportions more similar to those in other mosasaurs such as Plioplatecarpus. The postorbitofrontal forms its primary contact with the frontal rather than the parietal, and the supraoccipital is firmly attached to the ventral side of the parietal. The plane of articulation between the parietals and supratemporal is neither vertical (as in Varanidae) nor horizontal (as in Mosasauridae), but forms an angle of about 55 degrees with the horizontal. The quadrate bears a long, ventrally-flared suprastapedial process but appears to lack an infrastapedial process. Close similarities in the structure of the frontal and parietal with “Clidastes” sternbergii support referral of the latter to Halisaurus, but reference of Phosphorosaurus ortliebi to Halisaurus is questionable. Halisaurus has been recorded from the Santonian to the late Maastrichtian.

A new species, Balbaroo fangaroo, of balbarine kangaroo is described from the freshwater limestone deposits at Riversleigh, northern Australia. The type specimens include two partial skulls which reveal hitherto unknown characters of Balbarinae and provide new evidence relevant to the resolution of the phylogenetic affinities of Balbarinae. A number of the newly-revealed characters, e.g., squamosal-frontal contact on the walls of the neurocranium, are argued as being plesiomorphic for Macropodoidea.

Hypertrophied upper canines which occur in the paratype, have never previously been recorded in kangaroos and represent an example of evolutionary convergence between these herbivorous marsupials and ungulate eutherians.

The early Miocene Durudawiri inusitatus new genus and species (Marsupialia: Phalangeroidea) is described from the Riversleigh World Heritage Property in northwestern Queensland. It appears to represent the plesiomorphic sister group of the late Oligocene species of Miralina from South Australia. Its molar morphology is not as complex as that of species of Miralina or ektopodontids, but it is more complex than that of phalangerids. The degree of morphological difference between species of Durudawiri and Miralina suggests subfamilial distinction for the two groups. Strange cusps on the upper molars could be interpreted as either large neometaconules and paraconules, or lingually-displaced metacones and paracones with very large stylar cusps on the buccal shelf.

The mammal faunas from the upper Eocene and lower Oligocene from four localities in the Sierra Palomera (province of Teruel, Spain) are described: Villarrosano 1, 12, 14, and Aguatón. Two new species of rodents, Treposciurus manentis (Pseudosciuridae) and Bransatoglis attenuatus (Gliridae), are described from Aguatón. Comparison of the associations from the Sierra Palomera with the European standard succession (MP zonation) suggests a late Eocene age (MP 19–20) for Villarrosano 1 and Villarrosano 12 and a early Oligocene age for Aguatón and Villarrosano 14 (MP 21). The dental morphology and the relative abundance of the different mammal taxa from Villarrosano 1 and Aguatón suggest a more open environment in upper Eocene than in the early lower Oligocene in this basin.

Ediacaran fossils from the southwestern Great Basin may help constrain regional Vendian-Cambrian biostratigraphy and provide biogeographic links between facies in this region and elsewhere. Locally, trace fossils suggest the Vendian-Cambrian boundary occurs within or below the upper third of the lower member of the Wood Canyon Formation. Ediacaran soft-bodied and tubular fossils, including the frondlike fossil Swartpuntia and tubular, mineralized or agglutinated fossils similar to Archaeichnium, Cloudina, Corumbella, and Onuphionella occur in the lowermost Wood Canyon Formation. Discoidal forms referred to Nimbia occur in both the lowermost Wood Canyon Formation and the underlying strata of the Stirling Quartzite. These fossils occur directly below Lower Cambrian trace fossils, including Treptichnus pedum, and confirm the persistence of the Ediacaran biota to near the base of the Cambrian. These faunas may also help strengthen previously proposed correlation schemes between the two main facies belts of the southwestern Great Basin (the Death Valley and White-Inyo facies), because a nearly identical Vendian-lowest Cambrian succession of faunas occurs in both regions. Lastly, lack of cosmopolitan Ediacaran faunas in these strata suggests a paleobiogeographic link between the southwestern U.S. and southern Africa in Vendian time.