The remarkable brachiopod Xianshanella haikouensis, from the Early Cambrian Chengjiang Lagerstätte, was briefly reported based on only two extraordinarily preserved specimens. Details of valve interiors remain unknown due to a lack of available material. We herein reillustrate the holotype of X. haikouensis, and, on the basis of many additional specimens from the type locality, provide further information on this brachiopod taxon, including shell ornamentation, a U-shaped digestive tract, mantle canal systems, lophophores, muscle scars, and well-defined visceral areas in the valves. This exceptional brachiopod is characterized by a biconvex, rounded, knob-shaped shell lacking visible pseudointerarea in the valves, an elongate and muscular pedicle, and, especially, its possession of exceptional setal fringes. A restudy of a number of new specimens justifies assigning Xianshanella to the family Obolidae. The elongate and horny setae of X. haikouensis, coupled with the massive pedicle in many cases with its end attached to shells of other animals, indicate that this species was an epibenthic, sessile suspension feeder, attached by a pedicle.

A new multicostate rhynchonellid brachiopod Jakubirhynchia occurs in the Hettangian (Early Jurassic) carbonate deposits of the West Carpathians. A comparison with externally similar multicostate rhynchonellids from the Hettangian–Sinemurian carbonate deposits of the Alps shows their congeneric and conspecific status, indicating relatively wide regional distribution in the Early Jurassic of the western Tethys.

Diagnostic characters include conjunct deltidial plates, divided, vertically inclined inner hinge plates forming sessile septalium, and subfalciform crura with relatively complex, serrate terminations and broad outline in lateral view. Although the shape of hinge plates and crura may vary according to shell convexity and shell orientation during serial sectioning, two-dimensional restorations of cardinalia and crura show their distinctive morphology. It is important to note that some of the cardinalia details and crural shape can be detected only with very short between-section distances. Based on external characters, Jakubirhynchia is a homeomorph to another multicostate rhynchonellid, Calcirhynchia, typical of the Hettangian and Early Sinemurian of the northwestern Europe province and reported also from the Tethyan province. This suggests that original distribution of Calcirhynchia might not be so wide and postextinction multicostate rhynchonellids were taxonomically more diverse as was previously supposed. Jakubirhynchia consistently occupies offshore, low-energy, micritic-rich habitats below storm wave base. It is the first reported Hettangian member of the family Basiliolidae and may bridge the gap between the Carnian Veghirhynchia and Early Jurassic basiliolids. Preextinction, Norian and Rhaetian brachiopods that are close morphologic relatives of Jakubirhynchia are known from outside the western Tethyan area only.

Four species of isorophinid edrioasteroids, Ulrichidiscus forbesi n. sp., Neoisorophusella whitesidei n. sp., Postibulla westergaardi n. sp., and Parapostibulla graysoni n. sp., are described from unnamed unit 1 of the Golf Course Formation, Dornick Hills Group, Lower Pennsylvanian (Morrowan), at Forbes Ranch, north of Marietta, southern Oklahoma. This locality is the first report of edrioasteroids attached to extraformational clasts, and they exhibit extremely high specimen density and the highest taxonomic diversity known from the post-Ordovician. The associated fauna consists of the stemless crinoid Paragassizocrinus tarri, serpulid worm tubes, and the acrothoracic barnacle boring, Rogerella, along with a few brachiopods, rugose corals, and other open marine organisms. Edrioasteroids show no preference for clast type, size, or shape. Intraspecific spatial competition is shown by polygonal specimen outlines in highly crowded conditions, whereas interspecific competition results in specimen overgrowth in a predictable manner.

We used up to 28 morphological characters to discriminate and describe species of the genus Cupuladria based on entire colony specimens collected from both coasts of the Isthmus of Panama. The characters included a combination of zooidal features traditionally used in cheilostome taxonomy and nontraditional characters such as colony size, shape, and an index of calcification of the colony, as well as the size of the basal sectors and their number of pores. Species were discriminated by a series of repeated multivariate cluster and discriminant analyses until the majority of specimens were assigned to their putative species with high statistical confidence. Nontraditional characters contributed significantly to the power of the analyses. Colonies fell into two highly distinct groups most clearly recognized by the presence or absence of vicarious avicularia, which agrees well with previous molecular genetic analyses. Further analyses of each of these two groups considered separately resulted in the discrimination of eight species. These include two previously described Caribbean species, C. biporosa Canu and Bassler, 1919 and C. surinamensis Cadée, 1975, and six new species: C. multesima, C. incognita, C. cheethami, and C. panamensis from the Caribbean, and C. pacificiensis and C. exfragminis from the eastern Pacific. There was also good correspondence between major clades within these morphologically defined groups and the previous molecular analysis, although 20% of the specimens could not be distinguished from their cognate (“geminate”) species from the opposite ocean. The high ratio of undescribed to described species and higher diversity in the Caribbean than eastern Pacific agree well with newly described patterns from other cheilostome genera based on similar analyses. Quantitative morphometric studies are essential to study biologically meaningful patterns of cheilostome speciation and macroevolution in the fossil record.

Study of the oldest macluritid gastropod, Macluritella stantoni Kirk, 1927 from the Lower Ordovician of Colorado, has revealed that its early whorls are openly and dextrally coiled, in contrast to those in later teleoconchs which are sinistrally coiled. This is the first documentation of heterostrophic coiling in members of the Macluritoidea, which have been considered to be dextrally hyperstrophic. Juvenile M. stantoni may be interpreted as dextrally orthostrophic and, thus, it had the same type of soft-body-shell arrangement as the vast majority of living and fossil gastropods. This intepretation also suggests that the Macluritoidea evolved from the dextrally orthostrophic gastropods, and their dextral hyperstrophy is derived and not a primary feature. In addition, occurrence of shell heterostrophy in M. stantoni brings additional evidence that the Macluritoidea and Onychochiloidea are not closely related taxa. Relationships between the Macluritoidea and Euomphaloidea are still uncertain. This study provides the oldest evidence (Early Ordovician) for shell heterostrophy in the class Gastropoda.

Madrynomya bruneti n. gen. and sp. is an undescribed bivalve collected from the late Miocene Puerto Madryn Formation in northern Patagonia. The specimens were collected together with other generally well-preserved mollusks from a parauthochtonous assemblage within a fine-grained sandstone. Based on their unique shell morphology, the specimens are placed in the Modiomorphoidea, a group of bivalves known only from the Paleozoic and Mesozoic. This conclusion is based on comparisons with other bivalve taxa such as Mytiloida, Dreissenidae, Modiomorphidae, Hippopodidae, and Anomalodesmata, which they resemble in different morphological features. However, careful inspection of key characters suggests that none of them are closely allied to this new genus, and placement in the Modiomorphidae is only tentative until more material is found and further characters, such as shell microstructure, can be properly analyzed. Likewise, an accurate reconstruction of this bivalve's life habit is presently impossible to determine with the two available specimens, but an endobyssate mode is probable, as has been inferred for Myoconcha.

Caribbean reefs underwent significant biotic change during the Late Oligocene and Early Miocene. This was a critical time in the evolution of the modern Caribbean fauna characterized by increasing endemism resulting from regional extinction of lineages that survive in the modern Indo-Pacific. An understanding of the dynamics and potential causes of the Oligocene/Miocene transition, however, is hampered by the relative lack of well-preserved Oligocene to early Miocene coral faunas in the Caribbean. Here we examine new exposures in the Culebra Formation of Panama that contain a well-preserved coral fauna of Early Miocene age. Taxonomic, stratigraphic, and paleoecologic study of the Culebra Formation exposed along the Gaillard Cut of the Panama Canal allows us to infer the paleoenvironments and reef coral communities from the Panama Canal Basin during this critical interval. The Culebra Formation consists of a deepening upward sequence with shallow-lagoon sediments at the base, overlain by fringing reef facies in the middle of the section, and open-shelf to bathyal facies at the top of the section. We recovered 31 species of reef corals from a combination of new and old collections. Comparison of our collections with other Late Oligocene to Middle Miocene reef coral assemblages confirms that there was a major faunal turnover after deposition of the Upper Oligocene Antigua Formation. This turnover consisted of a large number of extinctions followed by an increased rate of first occurrences so that regional diversity did not change appreciably. Improved stratigraphic resolution at this and other Caribbean localities is required to understand fully the dynamics of change during the Oligocene/ Miocene transition.

Upper Tithonian (Jurassic) ammonites occur in the Chinameca Formation at Chinameca, southern Veracruz, eastern Mexico. The fauna includes Eopaquiericeras peraltai n. gen. and sp. and E. pazi new genus and species of the family Platylenticeratidae, Chinamecaceras maldonadoi n. gen. and sp. of the subfamily Aspidoceratinae, Veracruciceras ruizi n. gen. and sp. and V. myczynskii n. gen. and sp. of the subfamily Simoceratinae, Durangites zigzagcostatus n. sp., and representatives of Haploceras, Salinites, Kossmatia, and Andiceras. Kossmatia is the most abundant and biostratigraphically significant ammonite in the Chinameca fauna and its age significance and distribution in Mexico is discussed. In addition, a comparison of the suture lines of Kossmatia and the related older genus Lemencia indicates that they both belong to the Tithonian subfamily Richterellinae rather than the Upper Oxfordian–Kimmeridgian families Ataxioceratidae and Lithacoceratidae. The Chinameca ammonites have affinities with taxa of the same age from central and northern Mexico, Cuba, and the southern United States.

Holmiids are a major component of the trilobite fauna in the middle part of the Montezuman Stage, the lowermost stage of the Cambrian of Laurentia with a continuous trilobite record. They are less common in the upper Montezuman where nevadiids predominate and other trilobite families appear. New material from western Nevada allows a revision of these holmiids. Palmettaspis parallela Fritz, 1995 and Palmettaspis cometes (Fritz, 1995) are assigned to a new genus, Montezumaspis, based primarily on thoracic characters, including a prominent axial spine on the thorax. A second new genus, Grandinasus, is based on Esmeraldina argenta (Walcott, 1910), in which the L3 lobe is incorporated in an expanded anterior lobe (LA) of the glabella. New species described are Esmeraldina elliptica, Grandinasus auricampus, G. patulus, Holmiella falx, and H. millerensis. The Laurentian taxa appear to be more primitive than the holmiids of Baltica by having simple, unfurrowed ocular lobes that are separated from the LA by an axial furrow. Three informal biofacies are suggested with a holmiid-dominated biofacies in a deep subtidal dysoxic environment, and two nevadiid-dominated biofacies in shallower subtidal environments.

We describe a new tritheledontid, Elliotherium kersteni n. gen. and sp., on the basis of a partial skull collected from the lower Elliot Formation (Upper Triassic; Euskelosaurus Range Zone) on the farm Beatrix, Free State Province, South Africa. Although similar to Pachygenelus, the genus differs from other South African tritheledontids in its higher maxillary postcanine tooth count, lack of labial cingula on the upper postcanine teeth, shorter secondary palate, retention of a median vomerine ridge behind the secondary palate, and smaller interpterygoid vacuity. With regard to these features, Elliotherium is most similar to the South American tritheledontid Chaliminia. Elliotherium is autapomorphic in its possession of a long parasphenoid rostrum, ventrally depressed secondary palate, medially convex margins of the interpterygoid vacuity, and a thin lamina of palatine covering the interpterygoid vacuity. Although Elliotherium is the stratigraphically lowest positioned tritheledontid from southern Africa, it is still probably later occurring than the South American taxa Chaliminia or Riograndia. Based on a revision of a previous analysis of advanced cynodont relationships, we propose a sister-group relationship between Elliotherium and Chaliminia, although support for this pairing is weak.

Morphological and biometrical variability is analyzed in Hipparion primigenium (V. Meyer) from four Vallesian and Turolian locations in Spain (Masía de Barbo, Puente Minero, Nombrevilla, and Los Valles de Fuentidueña). Previously unstudied remains of Hipparion from La Roma 2 (Teruel Province, Spain) are described and tested by multivariate analysis. This form is compared with: 1) Hipparion primigenium (or Hippotherium primigenium) from the above-mentioned Spanish localities; 2) large-sized specimens from Çalta (Turkey) and Pavlodar (Kazakhstan); 3) forms from the locality type of Eppelsheim, Höwenegg, and Dürkheim (Germany), and Nikiti 1 (Greek); and 4) specimens from two other Spanish localities, Concud and Venta del Moro. Hipparion remains from La Roma 2 are identified as Hipparion laromae n. sp. by body mass and morphological characteristics, and confirmed by bivariate and multivariate analyses. The faunal assemblages indicate a late Vallesian age (MN10) for La Roma 2 locality and an early Turolian age (MN11) for the Puente Minero locality.

Two new records of gomphotheriid proboscideans, one identified as Rhynchotherium and the other as Cuvieronius, are reported in México. Both records are in the southwesternmost points of their known distributional range.

The remains of both genera consist of molars and tusks. Their measurements were compared with data available from the literature and collection specimens. The molar index of Rhynchotherium shows statistical differences between m2 and M2, and m3 and M3. However, differences between the m3 from both genera are not statistically significant, despite slight morphological differences.

This suggests that metric and morphological information should be included for a reliable identification of isolated molars and, if available, any other data of the associated tusk.

All known records relating to both genera suggest that they found southwestern México favorable for use as a dispersal corridor to South America, likely due to the region's tropical or subtropical climate. However, some distributional gaps in central México need to be resolved for Rhynchotherium. There are also important populations of Cuvieronius in central México, and preliminary information suggests that they occupied at least parts of eastern México, as well.

A new eschrichtiid mysticete was recovered from the Late Pliocene Yuchi Formation, Teshio Town, Hokkaido, Japan. The specimen is relatively well preserved, comprising a posterior part of the skull, periotics and tympanic bullae, several incomplete cervical and thoracic vertebrae, ribs, and forelimb elements including scapula, humerus, ulna, and several phalanges. Its small size, unfused epiphyses of vertebrae and long bones (humerus, radius, and ulna) indicate that the individual is physically immature. It is identified as eschrichtiid based on diagnostic characters, including paired occipital tuberosities, large occipital condyles, the posteriorly concave exoccipital lateral to the occipital condyle, the cochlear portion of the periotic extending anteromedially, the relatively small and somewhat triangular anterior process of the periotic, and the proportionally large vertebral foramen relative to the vertebral body. Because all verified eschrichtiids are of Pleistocene age, the Teshio eschrichtiid significantly extends the temporal range of the group.