The fulcrate thorax of Stygina has the articulating furrow and a long articulating halfring, no pleural furrow, and the facetted outer portion of the pleura has the doublure terminating outside the fulcrum. In the type species the glabella is inflated and the axial furrows partially effaced; in other species inflation is not accompanied by such effacement. Distinctions between genera of Stygininae are based on cephalic characters, including the length (sag. and exs.) of the preglabellar area; the variability of these characters makes such distinctions difficult to define. Eobronteus has the forwardly-expanding glabella, three pairs of glabellar furrows, rostral plate and hypostome typical of Siluro-Devonian Scutelluinae. The relationship between the two subfamilies is shown by morphology and by ontogeny. It is doubted that Styginidae had an origin in common with Illaenidae; the characters suggesting a relationship between Nileus and illaenids are explored. To improve the classification of Trilobita, the search for Cambrian ancestors of Ordovician families needs to be intensified, and characters of the entire axial region should be taken into account. The impendent condition of the hypostome is homeomorphic and is of less significance in classification than the natant and conterminant conditions. Effacement of axial furrows of the cephalon is a trend displayed in Stygininae, and is another homeomorphic character that is not a reliable guide to relationship.

Leodia divinata new species is described from Early Pliocene deposits in Venezuela. It is only the second known species of Leodia, which was otherwise represented by a single extant and Late Pleistocene species, L. sexiesperforata. We also provide an overview of the characters that distinguish Leodia from other mellitid genera and that distinguish L. divinata from L. sexiesperforata. The evolutionary importance of L. divinata is discussed, along with its contribution to our knowledge of the phylogeny of the Mellitidae. It is now possible to partially fill a major and previously vexing gap in the stratigraphic record of the mellitids, and place in a phylogenetic context the strong preference of modern Leodia for biogenic, calcareous sand bottoms.

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.

Collections from upper Ibexian (Tulean Stage) rocks of western United States, from the Canning Basin in western Australia, and from the Argentine Precordillera contain a seximembrate apparatus of multidenticulate conodonts whose elements have been included by authors in species of Prioniodus Pander, 1986, and Reutterodus Serpagli, 1974. The individual elements as well as the complete apparatus are not consistent with assignment of the species to either of these genera or to any other extant genus. A new generic name, Stiptognathus Ethington, Lehnert, and Repetski, is proposed with Reutterodus borealis Repetski, 1982, as type species. The apparatus consists of Pa, Pb, Sa-c, and M elements; the genus represents either the Prioniodontidae or the Periodontidae.

An unusually diverse fauna of biserial graptolites has been recovered from the Kajrak and Urubulak formations in the Kurama Range of eastern Uzbekistan. The fauna consists of 26 distinct taxa, 24 of which are systematically described and illustrated. The entire fauna can be assigned to the Akidograptus ascensus–Parakidograptus acuminatus Biozone, which is earliest Rhuddanian (early Llandovery) in age. Within this biozone, however, three regionally distinguishable subzones can be recognized, the N. lubricus, A. cuneatus and H. sinitzini subzones. New taxa described are Normalograptus larini, Normalograptus skeliphrus, “Paraclimacograptus” kiliani kuramaensis, “Glyptograptus” jerini, and “Glyptograptus” ugurensis. New combinations described are Normalograptus acceptus (Koren’ and Mikhaylova, 1980), Normalograptus bicaudatus (Chen and Lin, 1978), Normalograptus jideliensis (Koren’ and Mikhaylova, 1980), Normalograptus lubricus (Chen and Lin, 1978), Normalograptus mirnyensis (Obut and Sobolevskaya, 1967), and Sudburigraptus illustris (Koren’ and Mikhaylova, 1980).

Decapod crustaceans bearing major claws with long, slender fingers armed with pectinate (comblike) denticles have been described in six genera arrayed within three families (Polychelidae, Nephropidae, and Ctenochelidae) in three infraorders (Palinura, Astacidea, and Anomura, respectively). Only one or a few genera in each infraorder exhibit this claw form. The pectinate claw form is confidently interpreted as having evolved independently in four lineages: once in the Polychelidae, once in the Ctenochelidae, and twice in the Nephropidae. Three of the lineages are known from both the fossil record and modern seas; the polychelid form is known only from Jurassic rocks. Convergence in this claw form developed to the extent that isolated fossil claws (i.e., claws without associated bodies) have commonly been misidentified at high taxonomic levels. The fossil record confirms what seems intuitively reasonable: that claw morphology is prone to convergence and should not, by itself, be given a high degree of taxonomic importance.

Plate homologies are identified and discussed in primitive representatives of cornute and mitrate stylophorans. Comparative morphological analysis suggests that: 1) Lagynocystida are digital-bearing mitrates; 2) Peltocystida are glossal-bearing mitrates; 3) in Mitrocystitida, glossal and digital are incorporated into a closed marginal thecal frame or modified into articulated posterior spines (Anomalocystitidae); 4) Ovocarpus? circularis is synonymized with O. moncereti; 5) Chauvelia discoidalis and Mitrocystites riadanensis are both assigned to the genus Aspidocarpus; 6) Mitrocystella barrandei is assigned to the new genus Promitrocystites. The original reconstruction of Vizcainocarpus dentiger proposed by Ruta, (1997a) is modified, as a result of the identification of two additional plates in the posterior portion of the theca. The new species Vizcainocarpus rutai from the Tremadoc (Lower Ordovician) of Shropshire (England) is described and represents the oldest record of mitrocystitidan mitrates. V. rutai differs from V. dentiger in the relatively broader size of its zygal and marginals and in the presence, on the lower thecal surface, of a peripheral fringe of fibrillar stereom. A cladistic analysis of selected stylophoran taxa based on the proposed plate homologies indicates that: 1) cornutes and mitrates are sister-groups, both deriving from a Ceratocystis-like ancestor; 2) Peltocystida and Mitrocystitida are sister-groups; 3) Lagynocystida is sister-group of (Peltocystida + Mitrocystitida); 4) Lobocarpus is not a cornute but a primitive Cambrian mitrate belonging either to the stem-group of Mitrocystitida or to the stem-group of (Peltocystida + Mitrocystitida); 5) Anomalocystitidae represents a family of the suborder Mitrocystitida.

A skull representing a new genus and species of Late Triassic temnospondyl, Rileymillerus cosgriffi, is described from the Cooper Canyon Formation, upper Dockum Group of Garza County, Texas. Rileymillerus resembles Latiscopus disjunctus in size and proportions, but the very poorly preserved unique type specimen of L. disjunctus indicates that the taxon should be considered a nomen dubium. Characters of R. cosgriffi include its small size combined with relatively small laterally-facing orbits, relatively high skull, lack of lateral line canals, lateral exposure of the palatine on the skull surface, and lack of otic notch/quadrate angle. No postcranial material can be definitely associated, although we describe a partial vertebral column that might pertain to R. cosgriffi. Relationships of R. cosgriffi are uncertain. The possibilities of a close relationship to Almsauridae, Tupilakosauridae or (especially) Brachyopoidea are explicitly examined, but for the present we consider R. cosgriffi as Temnospondyl incertae sedis. Characters described in the text have been converted to the tripartite (part, feature, state) standardized format developed for the PRESERVE web site, and are presented as a 125-character data matrix in the Appendix.

The Upper Olentangy Shale of Ohio, a green pyritic shale interbedded with thin dark gray shale beds, disconformably overlies the lithologically similar Middle Devonian Lower Olentangy Shale. The muds were deposited in a quiet offshore environment on the distal margin of the Appalachian Basin during the Late Frasnian through Early Famennian. The Upper Olentangy Shale contains abundant and diverse conodonts of MN Zone 13 and the Middle triangularis Zone. The Frasnian-Famennian boundary is 4-8 cm below the base of the Huron Shale at the Olentangy Shale type section in Delaware, Ohio. The boundary interval is a green shale containing a mixed highest Frasnian (e.g., Palmatolepis bogartensis, P. linguiformis) and lowest Famennian (e.g., P. delicatula, P. subperlobata, P. triangularis) conodont fauna. An ash horizon, pyritic bed, finely laminated dark shale, and a thin green-blue shale comprise the upper 3 cm of the Olentangy, and contain a conodont fauna indicative of the Middle triangularis Zone.

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.

Populations of the widely distributed Early Ordovician conodont Paracordylodus gracilis Lindström, 1955, have been measured and studied in detail. Natural clusters and rich collections of isolated elements allowed calculations of size frequency distributions and construction of survivorship curves. Small morphological differences, as well as dissimilarities in population structure between collections from separate areas, were observed. This led to the recognition of Type A populations from Kazakhstan and other Arenigian warm water, low latitude regions and Type B populations from Baltica and other areas with cool water, mainly located at high latitudes in the Arenigian.

A partial skeleton of a short-necked plesiosaur excavated from the Upper Cenomanian of the Middle Yezo Group of Hokkaido, Japan, includes disarticulated vertebrae, the right half of the pectoral girdle, fragments of the pelvic girdle, ribs, gastralia, and gastroliths. Gastroliths are unusual in short-necked plesiosaurs. Skeletal characters indicate that the specimen belongs to the Family Polycotylidae, well known from North America, the former Soviet Republics, and possibly from New Zealand. They are rare in East Asia and hitherto unknown from Japan. Extensive ossification indicates that this specimen is an adult individual, yet it is smaller than the adult specimens of other known polycotylids. The elongated epipodial bones are a unique character of the specimen but are probably plesiomorphic. The fossil is evidence of biogeographical diversification of the family at the beginning of the Late Cretaceous.

All aspects of conodont paleontology rely on the identification and description of homologous anatomical units or elements. But the current schemes of anatomical notation and terms for orientation were formulated at a time when little was known of conodont anatomy or skeletal architecture, resulting in some confusion and difficulties in their application. With improving knowledge of conodonts, these problems are becoming increasingly acute.

In an attempt to address current problems, we introduce new terms for orientation in conodonts and their elements, and a modified scheme of anatomical notation. The principal axes of the conodont body are identified as rostrocaudal, dorsoventral, and mediolateral, with opposite lateral sides designated dextral and sinistral. Anatomical notation is defined according to topological relationships between elements with reference to the principal axes of the body and takes the form of letters with numeric subscripts (e.g., P1, P2, S0-S4). The ozarkodinid apparatus serves as a standard, but the Pn-Sn scheme can be applied rigorously to all taxa that are known from natural assemblages or where an hypothesis of topological homology can be inferred from secondary morphological criteria.

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 of Late Ordovician callocystitid rhombiferan (Glyptocystitidae), Lepadocystis decorus, is described from the Brainard Shale of north-central Illinois. This species is characterized by five pectinirhombs, open infralateral and lateral plate circlets, and well-developed ridges on the thecal plates. Lepadocystis decorus well illustrates that open vs. closed plate circlets in glyptocystitids can largely be a function of pectinirhomb length and is therefore in part an ontogenetically linked characteristic. Consequently, great care must be taken to assure maturity when using this feature in taxonomy.

A complete skeleton of Solnhofia parsonsi (Cryptodira, Eurysternidae) from the Kimmeridgian/Tithonian boundary of Schamhaupten, Germany provides the first complete understanding of the postcranial morphology of this genus. The here newly described postcranial characters are important in distinguishing Solnhofia from shell-based genera and thus help in resolving part of the parataxonomic conflict between shell-based and cranium-based turtle genera. This disparity originated during the last 150 years due to the history of fossil finds, preparation, and changing interests of researchers. Synonymies of Solnhofia with such turtle genera as Eurysternum, Idiochelys, Plesiochelys, Thalassemys, and Euryaspis can now be refuted. Similarities with Hydropelta are apparent, but not considered sufficient to support a synonymy. Newly observed or confirmed characters include the relatively large head (40 percent of the carapace length), the pentagonal carapace, the unique arrangement of bones and fontanelles in the pygal region, and the absence of mesoplastra, epiplastra, and an entoplastron.

The carcass of the new specimen was embedded in finely laminated limestones and shows little sign of disintegration or scavenging, suggesting hostile bottom conditions with very low water energy during deposition. This taphonomy agrees with recent published models for the origin of the lithographic limestones of southern Germany. Tooth marks along the posterior margin of the carapace are evidence of predation by a broad-nosed crocodilian. This is the first clear example for this type of predatorial interaction from the Upper Jurassic of Germany.

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 Rãdulescu 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.

A collection of 57,877 conodont elements that includes 39 species representing 30 genera was made from the upper part of the Phragmodus undatus Zone and the lower part of the Plectodina tenuis Zone (late Turinian–early Chatfieldian). Conodont samples were collected from 30 sections in eastern North America and Baltoscandia, where the P. undatus–P. tenuis Zone boundary projects into B. alobatus Subzone based on K-bentonite bed correlation. Elements previously assigned to form-species of Oistodus are shown to be apparatus associates in coniform apparatuses of Besselodus. Pseudobelodina manitoulinensis new species is described and the apparatus-based taxonomy of Scyphiodus primus and Staufferella polonica are proposed.

The poorly-known, long bodied, limb-reduced marine lizard Adriosaurus suessi Seeley, 1881, is reassessed. Adriosaurus and a number of other marine lizards are known from Upper Cretaceous (Upper Cenomanian-Lower Turonian) marine carbonate rocks exposed along the Dalmatian coast of the Adriatic Sea, from Komen, Slovenia, to Hvar Island, Croatia. A revised vertebral count reveals 10 cervical, 29 dorsal, and at least 65 caudal vertebrae. The projections previously interpreted as hypapophyses are instead transverse processes. Openings on the anterior part of the skull, previously described as external nares, are probably internal nares. Important features not noted previously include accessory articulations on all presacral vertebrae, pachyostosis of dorsal vertebrae and ribs, and the presence of two pygal vertebrae. Phylogenetic analysis of 258 osteological characters and all the major squamate lineages suggests that Adriosaurus and dolichosaurs are successive sister-taxa to snakes. This is consistent with their long-bodied, limb-reduced morphology being intermediate between typical marine squamates (e.g., mosasaurs) and primitive marine snakes (pachyophiids). The analysis further reveals that up to five successive outgroups to living snakes (pachyophiids, Adriosaurus, dolichosaurs, Aphanizocnemus, and mosasauroids) are all marine, suggesting a marine (or at least, semi-aquatic) phase in snake origins. These phylogenetic results are robust whether multistate characters are ordered or unordered, thus refuting recent suggestions that snakes cluster with amphisbaenians and dibamids (rather than aquatic lizards) if multistate characters are left unordered. Also, the recent suggestion that Pachyrhachis shares synapomorphies with advanced snakes (macrostomatans) is shown to be poorly supported, because the reinterpretations of the relevant skull elements are unlikely and, even if accepted, the character states proposed to unite Pachyrhachis and advanced snakes are also present in more basal snakes and/or the nearest lizard outgroups, and are consequently primitive for snakes.

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.