The postcranial skeleton of the Lower Permian temnospondyl Trimerorhachis insignis Cope, 1878 is described and figured in detail. Postcranial adaptations for an aquatic existence in T. insignis include the extensive ventral expansion of the interclavicle and clavicles and poorly ossified ends of the endochondral bones. The endochondral postcranial skeleton of T. insignis is paedomorphic through the process of neoteny, retaining an osteologically immature condition throughout morphogenesis. The endochondral postcranial elements display progressive morphological changes that do not stabilize in larger specimens, indicating indeterminate growth, with a correlation between size and degree of ossification. Some postcranial characteristics are present only in later morphogenetic stages of T. insignis.

Within the Temnospondyli, the postcranial skeleton of T. insignis is most similar to that of other members of the Dvinosauria. The morphology of the postcranial skeleton of T. insignis is consistent with a phylogenetic position more derived than the basal temnospondyls Balanerpeton woodi and Dendrerpeton acadianum, but less derived than the Euskelia plus Stereospondylomorpha. A sister-taxon relationship between the Dvinosauria and brachyopoids is not supported by postcranial characteristics of T. insignis.

Characteristics that develop last in morphogenesis in temnospondyls, and are consequently only present in well-ossified, morphogenetically mature temnospondyls, are absent in T. insignis due to paedomorphosis. Otherwise, the postcranial skeletons of T. insignis and other aquatic temnospondyls are similar to that of terrestrial temnospondyls, supporting the hypothesis that aquatic temnospondyls had terrestrial ancestors and are thus secondarily aquatic.

Two new species of the rhynchonellid brachiopod Probolarina are described, Probolarina neoleonensis new species and Probolarina papalotensis new species. They were collected from a Paleocene limestone lens associated with a diapir in the La Popa basin, northeastern Mexico. Thousands of these brachiopods occur in this lens and constitute the first report of brachiopods for the Difunta Group, from which a diverse paleobiota has been previously reported. This occurrence represents the oldest record for the genus in the Western Hemisphere, as the only other Paleocene occurence of this genus was reported from New Zealand. Recent studies suggest that the carbonate lentil from which the brachiopods were collected were deposited in the shadow-effect area adjacent to the diapir, which affected the sediment influx into the basin.

Description of two new species of macruran decapod crustaceans, Hoploparia uzbekensis and Linuparus dzheirantuiensis, from Late Cretaceous rocks in the Kyzylkum Desert, Uzbekistan, represents the first published record of decapods from that country. Hoploparia is considered to be an intact, integrated genus. Specimens of Hoploparia uzbekensis and Linuparus dzheirantuiensis collected from the Aitym and Bissekty formations, respectively, are preserved as altered cuticular material in a sandy matrix. Specimens of Hoploparia and Linuparus collected from the Uchkuduk and Dzheirantui formations, respectively, are preserved as ironstone replacements, an unusual preservation style for decapods. the cephalothorax on the specimen of Linuparus from the Dzheirantui Formation has been partially broken in a manner suggestive of predation. the lateral thoracic flanks of the holotype of Linuparus dzheirantuiensis bear a raised, ridged area suggestive of a stridulating structure. These genera, although cosmopolitan in the Cretaceous fossil record, have not been recognized previously in central Asia.

New material from the Late Mississippian Fayetteville and Caney Formations of the south-central USA supports the taxonomic revision of the Mississippian actinoceroid cephalopods. New representatives of the previously poorly known Rayonnoceras solidiforme, Campyloceras striatulum, and Campyloceras imoense are described. Carbactinoceras procerum new species and Elmoceras graffhami new genus and species are described, and the genus Campyloceras is emended. Character evaluation suggests the shape of the endosiphuncular deposits in the Actinoceratida and Pseudactinocerida are homoplastic because similar patterns of endosiphuncular deposits occur in distantly related nautiloid clades. Apex shape, however, is shown to have previously unrecognized potential for taxon discrimination. Cladistic analysis of 13 actinoceroid and pseudorthocerid nautiloids supports the splitting of the Orthocerida and the creation of a sister group to the Actinoceratida which is identical with the largely neglected Pseudorthocerida.

A brachiopod fauna from the Hogan Formation near Skunk Springs, western Utah, in the eastern Great Basin, USA, includes only the new taxon Duartea bruntoni n. sp., and other brachiopod taxa described for the first time in North America. the faunas are considered to be late Moscovian (late Desmoinesian) in age, which represents the first record of post-middle Desmoinesian brachiopod faunas within the Pennsylvanian of the Great Basin. Systematic analyses of the faunas suggest strong affinities with brachiopods previously described in South America and Russia, confirming the idea of faunal migration into the Great Basin. the migration of these faunas appears to correlate with the development of new oceanic currents in response to paleogeographic changes related to the formation of the Late Paleozoic Pangea.

The Late Ordovician and Early Silurian conodont faunas of northeast Russia are described, based on 39 conodont-bearing samples collected from Kanyon, Padun, Tirekhtyakh, Maut, and lower Sandugan Formations at Mirny Creek and Ina River sections, Omulev Mountains. The faunas are represented by a total of 776 identifiable conodont specimens assigned to 35 species representing 25 genera, among which a new species, Periodon mirnyensis, is established. Based on graptolite zones at the same locality and other conodont faunas worldwide, the faunas are assigned to the Caradocian, early Ashgillian, late Ashigillian, early Llandovery, and late Llandovery. The Ordovician faunas belong to outer platform to upper slope facies with a North Atlantic Realm affinity; the Silurian faunas are from slope and basin facies. The conodont faunas are the first to be described from the Kolyma Terrane, which has an enigmatic paleogeographic position during the Early Paleozoic.

Fourteen species of Volutidae are recognized from the Neogene of central to southern Chile. Seven species are known from previous descriptions: Voluta triplicata, V. alta, V. domeykoana, V. obesa, V. vidali, Proscaphella taverai, and Adelomelon reconditus. A neotype is designated for Voluta alta. Proscaphella gracilior, type species of the genus Proscaphella, is considered to belong to the genus Miomelon, which places Proscaphella in synonymy with Miomelon. Most species of “Proscaphella,” excluding the type species, form a separate group well distinguished from Miomelon, and for these the new genus Palaeomelon is introduced with Voluta triplicata as type species. Seven new species are reported: Palaeomelon tucapeli, Palaeomelon angoli, Adelomelon colocoloi, Adelomelon caupolicani, Miomelon lautaroi, Miomelon? pelantaroi, and Pachycymbiola? galvarinoi. Voluta triplicata, V. domeykoana, and Proscaphella taverai are included in Palaeomelon n. gen., Voluta obesa and V. alta are referred to Adelomelon, and Voluta vidali is referred to Pachycymbiola. the fossil record of the Recent volute genera Miomelon and Pachycymbiola extends back into the Miocene, Adelomelon is known from the Late Eocene, while Palaeomelon is known in Chile only from the Miocene. Species are morphologically very similar among genera, and from this it is inferred that separation of genera probably occurred in the late Paleogene.

A review and revision of the Paleozoic proto-stomatopods results in the recognition of a new species of Tyrannophontes Schram, 1969, T. gigantion, from the Middle Pennsylvanian Mazon Creek, Essex biota. A new family, Daidalidae, and new genus, Daidal, are required to separate a previously recognized taxon, T. acanthocercus Jenner, Hof, and Schram, 1998. Both Perimecturus pattoni Peach, 1908 and Gorgonophontes cf. fraiponti (Schöllmann, 2004) appear at present to be best placed within Daidal, the latter as a new species, D. schoellmanni. The genus Gorgonophontes Schram, 1984 is allocated to a new family, Gorgonophontidae. Members of the family Tyrannophontidae reveal features of their maxillipeds that clearly relate them as a sister group to Unipeltata. A cladistic analysis of all known Paleozoic Palaeostomatopoda Brooks, 1962 and Archaeostomatopodea Schram, 1969 reveals a series of stem-group proto-mantis shrimp that lead to the crown-group Unipeltata Latreille, 1825.

The Early and Middle Ordovician Orthocerida and Lituitida of Precordilleran Argentina are described, and their systematics and paleogeographic significance are revised. These cephalopods show a strong affinity to coeval faunas of North China, suggesting a location of the Precordillera at middle latitudes in the Southern Hemisphere east of the North China block and relatively close to the Gondwanan margin during the early Middle Ordovician. The descriptive terminology of characters of the septal necks, the position and shape of the siphuncule, and the shape of the connecting ring is improved. The distribution of these characters support an emendation of the Baltoceratidae, Sactorthoceratidae, and Proteoceratidae. Braulioceras n. gen. (Sactorthoceratidae) and Palorthoceras n. gen. (Orthoceratidae) are erected. The new species Braulioceras sanjuanense, Eosomichelinoceras baldisii, Gangshanoceras villicumense, and Rhynchorthoceras minor are proposed. Palorthoceras n. gen. from the Lower Ordovician Oepikodus evae Zone represents the earliest known orthocerid.

The Platteville crinoid fauna of northeastern Iowa consists of six species: Abludoglyptocrinus charltoni (Kolata, 1975), Carabocrinus sp. Kolata, 1975, Cupulocrinus plattevillensis Kolata, 1975, Ectenocrinus simplex (Hall, 1847), Merocrinus britonensis Kolata, 1975, and Porocrinus pentagonius Meek and Worthen, 1865. Other echinoderms include an unidentified cyclocystoid and several rhombiferan and crinoid plates. the echinoderms are mostly associated with a variety of passive suspension and filter feeders, principally brachiopods and bryozoans. Complete crowns and columns are available for the porocrinid and cupulocrinid, which lived at elevations of 28 and 50–60 mm above the seafloor, respectively. Although entire stems are not preserved, specimens from other stratigraphic units suggest that Abludoglyptocrinus charltoni, Ectenocrinus simplex, and Merocrinus britonensis occupied higher areas above the seafloor. the elevation of the carabocrinid is not known. the cyclocystoid was located on the seafloor. the crinoids are ecologically separated in two ways: different elevations above the substrate and food groove width, which is correlated with the size of the food items taken. the high-level crinoids mainly ate a narrow range of small items. However, the crinoids at lower levels caught many larger food particles and utilized a much wider range of food sizes. Cup growth of Cupulocrinus plattevillensis is isometric except for the heights of the infrabasals and radials, which exhibit significant positive and negative allometry relative to overall size. the proximal brachs are strongly allometric in which the widths increase much more rapidly than the heights.

Food gathering of some adult Upper Ordovician crinoids was modeled by means of filtration theory. The arm-branching patterns of the 13 species examined range from nonpinnulate isotomous arms to uniserial and biserial arms with numerous pinnules. Most taxa are roughly equivalent with respect to ambient current velocities and the nutrient contents needed from seawater. Two species with extensively branched arms have markedly higher nutritional requirements at any one ambient current velocity. The results are somewhat correlated with environment in the form of differential current velocities, water flow patterns, and food abundance and composition. The data are generally compatible with filtration theory and the environmental distributions of many Ordovician and other Paleozoic crinoids, and they reveal that Upper Ordovician crinoids had at least partially developed the ecological patterns seen in later Paleozoic crinoids. Various morphological, physiological, and behavioral changes can be employed by crinoids to alter their nutritional balance. The size distributions of food particles that are caught by the crinoids are modeled. These food particle distributions for the Ordovician fossils resemble those of modern crinoids. Relative to the population of food items, the distributions of particles that are trapped are shifted towards larger items because the crinoid filtration nets are more efficient at catching larger particles. Crinoids with relatively open filtration nets and large food-catching tube feet are generalized and feed on a wide range of food particles of a relatively large mean size. The more specialized taxa with extensively branched arms bearing small and closely packed food-catching tube feet are restricted to a more narrow range of smaller food particles.

Cenozoic marine deposits of forearc basins in southern Peru contain a molluscan fauna that includes 15 species of turritelline gastropods. Twelve species were previously known; ten from northern Peru or Chile and two species solely from southern Peru. Three new fossil species are described: Turritella riverae, Turritella cruzadoi, and Turritella salasi. Six species of turritellines with crenulated primary spirals, a distinctive spiral ontogeny, and which are mostly endemic to Peru and Chile, are assigned to Incatella n. gen., including I. cingulata (Sowerby, 1825), I. cingulatiformis (Möricke, 1896), I. chilensis (Sowerby, 1846), I. leptogramma (Philippi, 1887), I. hupei Nielsen, new name (= Turritella affinis Hupé, 1854), and I. trilirata (Philippi, 1887). Most Paleogene taxa range from northern to southern Peru, while most Neogene taxa, including all species of Incatella, range from Peru to Chile. This biogeographic asymmetry is attributed to a series of biotic events (e.g., extinctions, immigrations) impelled by global oceanographic changes acting locally in a regime of coastal upwelling.

This paper describes cranial and postcranial remains from Alligator olseni White, 1942 and Alligator cf. mefferdi Mook, 1946. An earlier phylogenetic data set has been augmented with new data from these fossils. Although membership in the clade Alligator is generally in accord with previous analyses, neither strict consensus nor Adams consensus trees could resolve placement of all members. Several lines of evidence pertinent to Alligator biogeography are analyzed. Alligator may have dispersed from North America into Asia prior to 15 million years ago, but conclusive evidence is lacking.

Pterygotus monroensis from the Pittsford and Harris Hill members of the Silurian Vernon Formation, New York State, USA, is here assigned to Erettopterus osiliensis, previously known only from Saaremaa, Estonia, based on new material (carapaces, chelicerae, a prosomal appendage VI, several metastoma, genital opercula with appendages, an almost complete opisthosoma, and several bilobed telsons), and reexamination of the original specimens. Telson morphology indicates assignment to Erettopterus or Truncatiramus, but the differences between these two genera are here interpreted as insignificant, and all species are treated as belonging to Erettopterus. the much rarer Pterygotus? sarlei n. sp., a possibly basal pterygotid, also from the Pittsford Member, is based on two telsons with pterygotid-like marginal cuticular sculpture. the telson shape is unlike that of any other adult pterygotid; it is relatively similar to juvenile pterygotids and Slimonia, but lacks the long posterior spine found in Slimonia. These systematic revisions have implications for other pterygotid taxa. Pterygotus impacatus, from Estonia, is a junior synonym of E. osiliensis. P. waylandsmithi, from slightly higher in the Vernon Formation, and is transferred to Erettopterus based on similarities of the chelicerae to E. osiliensis.

The Horse Spring conodont succession in the Canning Basin replicates zones 6 through 13 of the thirteen-fold Frasnian zonation. Horse Spring, together with other Canning Basin sections, demonstrates the widespread application of the zonation. Furthermore, the recently formalized three-fold subdivision of Zone 13, which has been recognized in the Montagne Noire, Moroccan Meseta, and northern Ontario, is developed at Horse Spring and other Canning Basin sections.

The Canning Basin Frasnian is noteworthy for the high quality of preservation of the conodont faunas, the extremely low CAI values, and the abundance of elements in most collections. The emphasis in this paper is on the taxonomy of Frasnian Palmatolepis. Newly described species are: Palmatolepis beckeri, P. feisti, P. housei, P. klugi, P. nicolli, P. playfordi, P. uyenoi, and Polygnathus kirchgasseri. Complete and partial multielement apparatuses have been reconstructed for Palmatolepis playfordi and P. nicolli.

Six stratigraphically distinct trilobite faunas are recognized in the Lower Mississippian strata of the central United States. These faunas range in age from earliest Kinderhookian to Meramecian, and are, in ascending order: Pudoproetus missouriensis, Comptonaspis swallowi, Proetides insignis-Perexigupyge, Breviphillipsia semiteretis, Exochops portlockii, and Hesslerides bufo. Trilobite species diversity waxed and waned through the early Mississippian of the central United States, but reached its maximum during the late Kinderhookian within the Comptonaspis swallowi fauna. the Comptonaspis swallowi, Breviphillipsia semiteretis, and Exochops portlockii faunas of the mid-continent can be correlated with the C. swallowi, B. semiteretis, and Hesslerides arcentensis faunas of the Caballero and Lake Valley Formations of New Mexico. the vertical distribution, composition, and diversity variations among individual faunas suggest that they are evolutionarily discrete and therefore of biostratigraphic utility. Their stratigraphic distribution appears to be controlled by sea level and climatic fluctuations.

New Osagean trilobites identified and described are Exochops burlingtonensis n. sp. and Richterella carteri n. sp. from the Burlington Formation of Missouri, Australosutura osagensis n. sp. from the Keokuk Limestone of Missouri and the Arcente and Dona Ana Members of the Lake Valley Formation of New Mexico, and Spergenaspis boonensis n. sp. from the Boone Formation of Oklahoma.

New material of polyglyphanodontine lizards from the Late Cretaceous has been found in various localities in western North America. Several transversely oriented teeth representing a new species of Dicothodon were recovered from the Turonian of southern Utah. These specimens necessitate reassignment of Polyglyphanodon bajaensis to Dicothodon (Polyglyphanodon) bajaensis. From the Campanian of Utah, additional teeth and jaw fragments referable to Manangysaurus saueri have been recovered and this species is reassigned here to Peneteius (Manangysaurus) saueri. Also, an isolated tooth referable to Peneteius has been recovered from the Campanian of southern Texas. The results of a phylogenetic analysis support a monophyletic grouping of the transversely-toothed taxa with Bicuspidon as the sister taxon of Polyglyphanodontini new taxon, which is comprised of Polyglyphanodon, Dicothodon, and Peneteius. The phylogenetic analysis also places “teiid” lizards from the Cretaceous of Asia and North America in a monophyletic group, Borioteiioidea new taxon, which is the sister taxon to the Teiioidea (Teiidae + Gymnophthalmidae). This new hypothesis of the interrelationships of these taxa requires the reevaluation of several characteristics that were previously considered diagnostic for a more inclusive Teiidae. Another implication of our results is that Teiidae (sensu stricto) has no demonstrable pre-Tertiary occurrence. It appears that Teiioidea and Borioteiioidea diverged from a common ancestor by the Early Cretaceous. The Teiioidea entered South America and are currently represented by the Teiidae and Gymnophthalmidae, whereas Borioteiioidea radiated throughout North America with subsequent dispersal to Asia and Europe.

Proetid trilobites are described from three sections in two regions of southern Morocco. the sections are located at Jbel Gara el Zguilma (‘Zguilma’) and a neighboring section (‘near Zguilma’), near Foum Zguid; and at another locality (BD5) in the Ma'der Region, between the villages of bou Dib and Tazoulaït, near the town of Alnif. the trilobites described here are assigned to a proposed new genus, Timsaloproetus, with Cornuproetus (Sculptoproetus) haasi Alberti, 1971 as type species. Timsaloproetus haasi occurs in Eifelian strata of both Germany and Morocco (at BD5, and both of the sections near Foum Zguid). New Moroccan species of this genus are Timsaloproetus dibbanus and Timsaloproetus elguerrouji. the former occurs in upper Emsian strata at Zguilma, and the latter occurs in strata of early Eifelian age, with T. haasi, in both the Zguilma and near Zguilma sections.

The cranial anatomy of the Deseadan species Medistylus dorsatus (Ameghino, 1903) is described based on new and complete material from Cabeza Blanca (Chubut, Argentina). Medistylus is the largest of the Pachyrukhinae and the specimen described here is probably the best-preserved pachyrukhine skull known in the Paleogene of South America. Previously, the validity of the species and its phylogenetic affinities with Interatheriidae (Notoungulata, Typotheria) were ambiguous and not conclusive. The syntypes, now reported lost, were isolated teeth poorly described by Ameghino in 1903. This almost complete skull with teeth provides more diagnostic features in order to complete the knowledge of genus. Details about cranial and dental morphology allow the reassessment of Medistylus dorsatus and its inclusion within the subfamily Pachyrukhinae (Hegetotheriidae, Notoungulata). Its cranial and dental specializations and the apparent sympatry with its close relatives Prosotherium garzoni Ameghino, 1897 and Propachyrucos smithwoodwardi Ameghino, 1897 all imply a narrow niche partitioning among the Pachyrukhinae during the Deseadan (late Oligocene). The occurrence of three euhypsodont genera of Pachyrukhinae in the Deseadan of Patagonia reflects the major radiation of the rodentlike ungulates in the Cenozoic of South America and suggests a great paleoenvironmental difference between the late Oligocene faunas of Patagonia and those from Bolivia and Uruguay, where they did not live.

Trilobites from the Lower Cambrian succession at Angorichina in the eastern Flinders Ranges, South Australia, are described. Silicified material from the Mernmerna Formation reveals the presence of a new assemblage from the Pararaia bunyerooensis Zone, including the eponymous species, Yorkella aff. australis, Eoredlichia sp., Redlichia sp., and the new species Wutingaspis euryoptilos and Yunnanocephalus macromelos. Trilobites of the Pararaia bunyerooensis Zone show a strong affinity with those from the Yu'anshan Member of the Heilinpu Formation in Chengjiang and Jinning Counties, Yunnan Province, southwest China. the Pararaia bunyerooensis Zone is correlated with the Yunnanocephalus Assemblage subzone (upper Eoredlichia–Wutingaspis Zone) of the Chiungchussuan (=Qiongzhusian) Stage of China. Additional trilobites from Angorichina include Elicicola calva from the Wilkawillina Limestone, Estaingia occipitospina (Jell) new combination from the Oraparinna Shale, and Redlichia guizhouensis Zhou from the Wirrealpa Limestone. Australian Early Cambrian trilobite biozonation is reviewed, with discussion of distinct assemblages within the Pararaia janeae Zone that have the potential for zonal subdivision, and evidence to support the placement of the northern Australian Ordian/Early Templetonian Stage within the late Early Cambrian.

A possible paedomorphic lineage between Pararaia bunyerooensis and P. janeae is proposed. Adult specimens of P. janeae retain juvenile characteristics of the progenitor P. bunyerooensis. Retardation in onset of maturity in P. janeae resulted in the attainment of a larger adult size than in P. bunyerooensis, indicating the former species evolved via neoteny.