The Onychodontiformes is a poorly known sarcopterygian fish group, with four genera currently described, predominantly from the Middle-Late Devonian. A new onychodont, Bukkanodus jesseni n. gen. and sp., from the Fairy Formation, Victoria, Australia, is of Early Devonian (mid-late Pragian) age, representing one of the oldest known occurrences of this group. Other Pragian onychodonts are represented by a single lower jaw from China, while older occurrences (Lochkovian) include a lower jaw also from China and isolated teeth from Nevada. The Australian material, though disarticulated, includes skull, jaw, and palatal and dental specimens. These specimens share characteristics with younger onychodont taxa, including a laterally compressed tooth whorl with main and accessory rows containing an equal number of teeth, an anteriorly arched shape of the premaxilla, a lateral rostral bone participating in the orbital margin, parietals separated in the midline by small bones, the insertion of the basisphenoid region of the braincase into a posterior area on the parasphenoid, and an ethmoidal sensory canal running along the dorsal margin of the premaxilla rather than through the bone. Bukkanodus jesseni differs from other onychodonts in the presence of a distinct vomer, coronoids with fang pairs, a restricted herringbone pattern of ribs on enamel ridges of teeth, and the presence of a cluster of large pores on certain skull and jaw bones. The course of the ethmoid sensory canal and this cluster of pores are plesiomorphic features for the Onychodontiformes, also occurring in primitive sarcopterygian taxa such as Youngolepis, Powichthys, and Kenichthys. The opening of this cluster on the internal surface of the premaxilla resembles the rostral organ of derived coelacanths.

Upper Neoproterozoic successions in the North China and nearby Chaidam blocks are poorly documented. North China successions typically consist of a diamictite unit overlain by siltstone, sandstone, or slate. Similar successions occur in Chaidam, although a cap carbonate lies atop the diamictite unit. The diamictites in both blocks have been variously interpreted as Cryogenian, Ediacaran, or Cambrian glacial deposits. In this paper, we describe problematic macrofossils collected from slate of the upper Zhengmuguan Formation in North China and sandstone of the Zhoujieshan Formation in Chaidam; both fossiliferous formations conformably overlie the aforementioned diamictites. Some of these fossils were previously interpreted as animal traces. Our study recognizes four genera and five species—Helanoichnus helanensis Yang in Yang and Zheng, 1985, Palaeopascichnus minimus n. sp., Palaeopascichnus meniscatus n. sp., Horodyskia moniliformis? Yochelson and Fedonkin, 2000, and Shaanxilithes cf. ningqiangensis Xing et al., 1984. None of these taxa can be interpreted as animal traces. Instead, they are problematic body fossils of unresolved phylogenetic affinities. The fundamental bodyplan similarity between Horodyskia and Palaeopascichnus, both with serially repeated elements, indicates a possible phylogenetic relationship. Thus, at least some Ediacaran organisms may have a deep root because Horodyskia also occurs in Mesoproterozoic successions.

Among the four genera reported here, Palaeopascichnus Palij, 1976 and Shaanxilithes Xing et al., 1984 have been known elsewhere in upper Ediacaran successions, including the Dengying Formation (551-542 Ma) in South China. If these two genera have biostratigraphic significance, the fossiliferous units in North China and Chaidam may be upper Ediacaran as well. Thus, the underlying diamictites in North China and Chaidam cannot be of Cambrian age, although their correlation with Ediacaran and Cryogenian glaciations remains unclear. As no other Neoproterozoic diamictite intervals are known in North China and Chaidam, perhaps only one Neoproterozoic glaciation is recorded in that area.

The family Mixosauridae Baur, 1887 is a dominant group of Middle Triassic ichthyosaurs. Its generic composition has been controversial, but recent findings from southern China enabled Jiang et al. (2006) to recognize two monophyletic taxa within the clade, suggesting the presence of two genera within the family, namely Mixosaurus Baur, 1887 and Phalarodon Merriam, 1910. The latter genus, which was invalidated at one point (Nicholls et al., 1999; McGowan and Motani, 2003), was recently resurrected by Schmitz (2005) by validating its type species. Mixosaurus is Tethyan in distribution, whereas Phalarodon had been known mostly from North America and Spitsbergen, apart from a possible juvenile from Switzerland (Brinkmann, 1997, 1998). More recently, Jiang et al. (2003) reported a largely complete, yet poorly preserved skeleton as the first record of the genus Phalarodon from Asia and referred it to Phalarodon sp. However, important synapomorphies were not clearly identified, and evidence has since emerged that the specimen had been tampered with by farmers after it was collected. In the light of the cladistic analysis by Jiang et al. (2006), the referral of the specimen to the genus Phalarodon is questionable.

Two bivalved arthropods of the family Sunellidae Huo, 1965 are described from the Lower Cambrian Helinpu Formation of southwestern China: Sunella cf. shensiensis Huo, 1965 and Combinivalvula chengjiangensis Hou, 1987. Both taxa preserve soft anatomies, described here for the first time, including a pair of lateral eyes and a possible median eye, a trunk carrying flaplike appendages, and a simple gut with caeca. The family Sunellidae includes three genera: Sunella Huo, Combinivalvula Hou, and Jinningella Huo and Shu. In contrast to most other Cambrian arthropods with a larger bivalved carapace, especially those from the Burgess Shale–type deposits, sunellids lack a limbless abdomen protruding posteriorly beyond the carapace. This, coupled with a combination of a number of snared features (e.g., the presence of cardinal spines and distinctive anterodorsal sulcus, elongated valves, and median eye), appears to support sunellids as a clade. The distinctive anterodorsal sulcus extending from the anterodorsal corner to the anteromedian part of the carapace is regarded as an autapomorphy for this clade. Sunellids resemble Isoxys Walcott, 1890 to which they may be closely related; both possess a bivalved, elongated carapace with cardinal spines that almost entirely covers the body. However, neither cephalic appendages nor proximal portions of trunk limbs are visible in sunellids, and thus, their systematic position remains uncertain.

Examinations of the internal structures of microfossils provide important information about phylogenetic relationships and growth patterns. the internal structure of microfossils was first observed by sectioning during the late nineteenth century (e.g., Schlumberger, 1893, 1896), and further sectioning methods were developed in the twentieth century (e.g., Hemleben et al., 1977; Kennedy, 1978; Coleman, 1979; Nomura, 1983; Suzuki, 1998).

Since the 1960s, Chinese researchers have reported a series of bizarre paragastrioceratids associated with the endemic pseudohaloritids and/or kufengoceratins from the Permian Restricted-Sea area of Southeast China. They include Aulacogastrioceras Zhao and Zheng, 1977; “Paragastrioceras” carinatum Chao, 1965 (invalid name, =Chekiangoceras carinatum Ruzhencev, 1974, type species of the genus Chekiangoceras Ruzhencev, 1974); “Paragastrioceras” dongwuliense Zhao and Zheng, 1977; and Nodogastrioceras Ma and Li, 1998 (=Yongpingoceras Ma and Li, 1998; including “Paragastrioceras” dongwuliense). All these taxa share the following characteristic features: 1) an eight-lobed paragastrioceratid suture; 2) a variably shaped, evolute conch, and prominent sculpture with transverse ribs, nodes, and coarse strigae in all ontogenetic stages, suggesting an affinity with the subfamily Paragastrioceratinae; 3) and, by contrast, a conspicuous ventral sinus formed by growth lines and constrictions, indicating a phylogenetic relationship to the subfamily Pseudogastrioceratinae. These endemic Chinese paragastriocertids constitute a separate subfamily, distinct from both Paragastrioceratinae and Pseudogastrioceratinae, for which the subfamily Aulacogastrioceratinae is herein proposed.

Taxa belonging to the Ceratoikiscidae are described in detail from two measured sections of Member C of the Cape Phillips Formation exposed along Rookery Creek, Cornwallis Island, Arctic Canada. The sections encompass uppermost Sheinwoodian (top lower Wenlock) to the base of the Gorstian (base Ludlow) and are dated by graptolites assigned to the Cyrtograptus perneri–Monograptus opimus Zone (upper Sheinwoodian), the Cyrtograptus lundgreni Zone (lower Homerian), and the Colonograptus praedeubeli–Colonograptus deubeli Zone (upper Homerian). Radiolarians are found in great abundance throughout the lower Homerian, allowing for the establishment of the first appearance of the genus Helenifore Ormiston and Nazarov. Helenifore is emended to accommodate the Silurian species H. quadrispina n. sp. and H. speciosus (Furutani 1990). One new genus, Kappaforma, including the new species, K. insecta, is described, as is the new species H. quadrispina. Ceratoikiscum octapleura Renz and C. armiger Furutani are synonymized with C. lenoides Renz, and H. planus Umeda is synonymized with H. speciosus.

Canids invaded South American during the Pliocene (2.8–3.1 Ma BP) as part of the Great American Biotic Interchange, but their record on the continent is relatively poor until the Pleistocene. However, even the Pleistocene record of the group is patchy and biased, with few records for the northern part of South America. In this paper we describe a new assemblage of canids found at the Inciarte asphalt pits (Zulia, Venezuela). These remains are associated with a variety of extinct Pleistocene mammals dated between 25–27 Ka BP. Canids in this assemblage include Protocyon troglodytes (Lund 1838), Protocyon sp., Canis dirus Leidy, 1858, Urocyon cf. U. cinereoargenteus (Schreber, 1775), and an indeterminate canid. This is the first record of Urocyon Baird, 1758 from the Late Pleistocene in South America and constrains the timing of its dispersal to South America. The distributional record of Protocyon Giebel, 1855 and P. troglodytes is expanded 1,500 km north of previous records and constitutes the first record of these taxa in Venezuela. The presence of C. dirus at Inciarte constitutes the fourth locality for this species in South America.

The eurypterid Strobilopterus princetonii from the Lower Devonian Beartooth Butte Formation of Wyoming is redescribed, and previously unknown morphological features, including shape and position of eyes and ocelli are identified, and the prosomal appendages are described in more detail. The monotypic Erieopterus latus, based on a much smaller specimen from the same locality, shares a large number of characters with S. princetonii, and must be interpreted as belonging to the genus Strobilopterus. It is here interpreted as a juvenile S. princetonii, but exhibits extreme ontogenetic variation in the morphology of the swimming leg. The other monotypic eurypterid from the locality, Dorfopterus angusticollis, remains mysterious. It might be a S. princetonii telson, but evidence is inconclusive. The name of the Devonian eurypterid genus Syntomopterus is preoccupied for a beetle (Coleoptera: Insecta) and the replacement name Syntomopterella is proposed. The phylogenetic position of S. princetonii is problematic since it lacks unequivocal synapomorphies with other eurypterids, but the genus is showing more similarities to Syntomopterella, Erieopterus and Buffalopterus than it does to Dolichopterus, contrary to earlier suggestions.

Nine species, including two new species of decapod crustaceans, are described from the Paleocene Rancho Nuevo Formation, collected from two localities of the Parras Basin, southeast Coahuila state, Mexico. The astacid Enoploclytia gardnerae (Rathbun, 1935) is represented by a pair of large chelae and one cephalothorax. An incomplete nephropid carapace is identified as Enoploclytia sp. Partial specimens of a callianassid and a pagurid are described. One partial carapace representing Linuparus wilcoxensis Rathbun, 1935 is described. A new raninid, Macroacaena venturai new species extends the genus into Mexico. Paraverrucoides alabamensis (Rathbun, 1935) is the most abundant species, followed by Tehuacana tehuacana Stenzel, 1944 and Viapinnixa perrilliatae new species. Taxonomic affinities of this assemblage confirm influence of the Mississippi Embayment, particularly from Paleocene stratigraphic units of Texas and Alabama.

Three of Kitchin's (1903) trigoniid species, Trigonia trapeziformis, T. spissicostata, and T. cardiniiformis, have been frequently examined taxonomically, but their phylogenetic relationships remain uncertain. Taxonomic designations have ranged from grouping them within a single subgenus to separating them into different subfamilies. Principal factors affecting the previous studies include: excessive weighing of certain features from a typological perspective; phylogenetic relationships established on the basis of plesiomorphic characters which are applicable even at the family level. Although they are endemic to Kutch, India, species' ancestries were rarely sought from the regional taxa, a situation exacerbated by inadequate stratigraphic information. This study reveals that all the three species are both geographically and stratigraphically distinct, and their distribution is linked to major regression events. Since the latest Jurassic, the Kutch Basin experienced shallowing. The unstable environment triggered a substantial diversification of new forms. The present species are close morphologically to some endemic species of different genera. Detailed morphologic, morphometric, and cladistic analyses reveal affinities between ‘Eselaevitrigonia’ trapeziformis and Indotrigonia smeei, as well as ‘E.’ spissicostata and Opisthotrigonia retrorsa. It is believed that E. cardiniiformis evolved from ‘E.’ spissicostata. In each case, speciation took place in a very shallow, high-energy, nearshore environment and proceeded through various heterochronic processes. The pattern is consistent with a punctuated model of evolution. Gondwana fragmentation and rise of eustatic sea level during the Aptian opened up the central Indian oceanic corridor, prompting the spread of ‘Eselaevitrigonia’ to the Austral Province.

Ostracod faunas from the Lower to Middle Ordovician rocks of the Argentine Precordillera Basin (Gualcamayo and Las Aguaditas Formations) are studied. A new family, Garcianidae, is erected. One new genus, Jeanvannieria, and six species are recognized, two of which are new (Jachalipisthia bicornata and Jeanvannieria bulbosa). The diversity and composition of the Precordilleran ostracods is evaluated on the basis of previous taxonomic analysis and the fauna studied here. The diversity is moderate, with a peak of 50 species during the early Caradoc. The composition of the fauna is characterized by the dominance of podocopes with a high percentage of binodicopes and a lack of palaeocopes, which is in agreement with a deep shelf environment. The carbonate slope setting of the Las Aguaditas Formation is the deepest environment yet found with Ordovician ostracods and records a relatively diverse fauna. The presence of Ectoprimitioides suggests biogeographic affinities between the Precordillera and Laurentia. The rest of the fauna contains a high percentage of endemic genera and a mixture of genera with several affinities, Baltic, peri-Gondwanan, and Australian.

Lower Caradoc rhynchonelliformean brachiopods have been recovered from the uppermost part of the Postolonnec Formation and the base of the Kermeur Formation (Upper Aurelucian-lowermost Burrelian) below and above a significant oolitic ironstone bed in the Veryarc'h section, Armorican Massif, France. A new species, Tenuiseptorthis loii n. sp. and four species, Howellites sp., Drabovia pentagonomya Havlíček, 1971, Tafilaltia destombesi Havlíček, 1970 and Triplesia cf. T. simplex Havlíček, 1971 are described. These brachiopod taxa confirm, at generic and specific level, the very close paleobiogeographic relationships existing within the North Gondwana Realm between the Armorican Massif, Spain, Portugal and North Africa during Late Ordovician time.