A method of phylogenetic inference is proposed for taxa that are known from large samples spaced closely in time. The method employs elements of cladistic and stratophenetic methods, and consists of four steps. 1) Morphologically homogeneous clusters are recognized within temporally and geographically constrained samples. 2) Temporally disjunct and geographically dispersed taxa are recognized, and their anagenetic evolution and geographic variation documented. 3) A character matrix is constructed for the taxa and analyzed cladistically. 4) Resulting cladograms are used to construct a phylogenetic tree with additional input from temporal, morphological, ecological, and geographical data. This method supplements the use of cladistically analyzed morphological data with data that are not suited for cladistic analysis, and thus reduces the amount of unused data.

Reefs of the Middle Devonian Edgecliff Member of the Onondaga Formation in New York and Ontario, Canada, contain three distinct paleocommunities: the Phaceloid Colonial Rugosan Paleocommunity, the Favositid/Crinoidal Sandstone Paleocommunity, and the rare Delicate Branching Tabulate Paleocommunity. The reefs may be classified as mounds or composite structures based on the degree of intergrowth of the rugosan and favositid paleocommunities. Composite structures may be further subdivided into mound/bank, thicket/bank, and ridge/bank structures based on the degree of development of the rugosan paleocommunity. Geographic distribution of reef types suggests that these patterns of reef growth were controlled by water depth.

Early Ordovician brachiopods Spanodonta floweri (Cooper) and Aporthophyla tianjingshanensis? Fu from peninsular Thailand and the Langkawi Islands, Malaysia, and described and offer important confirmatory evidence for the Ordovician juxtaposition of the Shan-Thai terrane, the North China terrane, and Western Australia.

Two orthothecid genera, Bolitheca n. gen. (type species Orthotheca steinmanni Knod, 1908) and Neobactrotheca n. gen. (type species Neobactrotheca pharetra n. sp.) are described from Bolivian rocks of Emsian and Eifelian age. Two incomplete and poorly preserved hyolithids are also described, one tentatively assigned to the family Pauxillitidae. Because so few specimens are known, it is not possible to compare Bolivian Devonian hyoliths with faunas from other regions, which are also poorly known.

Evaluation of previously undescribed collections of Late Triassic Gryphaea from the North American Cordillera increases the temporal range and geographic distribution of the genus. Gryphaea (Gryphaea) arcuataeformis Kiparisova, G. cf. G. (Gryphaea) keilhaui Böhm, and a new species, G. (Gryphaea) nevadensis, occur in lower Carnian to upper Norian strata from Alaska, British Columbia, Oregon, and Nevada. The distribution is mostly primary with respect to the Upper Triassic North American Craton, and requires long-distance larval dispersal along the latitude of far-eastern Panthalassa. Unlike most modern oysters, the distribution of these Triassic gryphaeids may have been restricted to cool and deeper water environments.

An early Carnian age of Gryphaea (Gryphaea) arcuataeformis places this species as the oldest known Gryphaea. When combined with late Carnian and Norian occurrences from the North and South American Cordillera, these data indicate that a low-latitude origin for the genus cannot be overlooked. Gryphaeids survived the end-Triassic extinction event presumably by living in refugia.

A large, diverse, and well-preserved fauna of nonmarine mollusks has been recovered from the late Oligocene to early Miocene (Arikareean) fluviatile and lacustrine sediments that accumulated in four intermontane structural basins of western Montana. The Pupillidae are represented by 10 species, with nine new species and one new subgenus among three extant genera. The Gastrocopta are very diverse, with one new subgenus Ameralbinula represented by three new species, G. obesa, G. russelli, and G. oviforma, while three new species, G. tavennerensis, G. leonardi, and G. conica, are referred to the extant subgenus Vertigopsis Sterki, 1893. Gastrocopta miniscula cannot be referred to a subgenus with certainty. The remaining new species, Vertigo whitei and Pupoides montana, are referred confidently to extant subgenera. Vertigo arenula (White, 1876) is the only previously described species and its description is emended based on new material. The mammalian biostratigraphy of the Cabbage Patch beds is presented.

Llandovery Encrinurinae from the Whittaker Formation in the central Mackenzie Mountains include Cromus canorus n. sp., Distyrax cooperi n. sp., Distyrax n. sp. A, Perryus bartletti n. sp., and Encrinurus n. sp. Additional diversity of Distyrax Lane, 1988, demands a revised generic diagnosis with emphasis on pygidial homologies; new species are described from the Llandovery of Newfoundland and Ontario. Several characters suggest a sister group relationship between Distyrax and Encrinurus s.s. A lectotype is designated for the Llandovery species Encrinurus elegantulus Billings, 1866. Cromus canorus n. sp. is closely allied to other northern Laurentian Llandovery species. Synapomorphies of Cromus are inclusive for Encrinuraspis as revised by Snajdr, 1985. The long stratigraphic range and morphological conservatism of Cromus are correlated with occurrence in distal mudstone facies. Ontogenetic material for Distyrax n. sp. A, Cromus canorus, and Perryus bartletti is described, with consideration of librigenal spine homologies in Encrinurinae. Humaencrinuroides Nan, 1985, is a pliomerid of the new subfamily Quinquecostinae, and not a subgenus of Encrinuroides Reed.

Silurian (Llandovery–Ludlow) Encrinurinae from Wisconsin, Indiana, and Illinois include species of Balizoma Holloway, 1980, Curriella Lamont, 1978, Distyrax Lane, 1988, Encrinurus Emmrich, 1844, Mackenziurus Edgecombe and Chatterton, 1990a, and Nucleurus Ramsköld, 1986. Mackenziurus lauriae n. sp. is described from Wenlock strata of the Racine and Sugar Run Dolomites; nine segments in the holaspid thorax are the fewest known for any encrinurid. A square rostral plate is diagnostic of Mackenziurus. New morphological data are provided by Illinois specimens of Balizoma indianensis (Kindle and Breger, 1904) from the Wenlock–Ludlow Racine Dolomite, and of Curriella tuberculifrons (Weller, 1907) from the Llandovery Elwood–Wilhelmi Formations. Nucleurus n. sp. is possibly from Llandovery strata in Wisconsin. Distyrax n. sp. occurs in the Brandon Bridge Member (late Llandovery–early Wenlock) of the Joliet Dolomite in Illinois. The type pygidia and possible topotype material of Encrinurus nereus Hall, 1867, confirm assignment to that genus as currently viewed; this reefal species is distinct from the closely related inter-reef species E. egani Miller, 1880, and appears to be distinct from reefal E. reflexus Raymond, 1916. Lectotypes are selected for these Encrinurus species.

Twenty-four fragmentary specimens and numerous disarticulated plates of a new clavate agelacrinitid edrioasteroid were collected from the Middle Pennsylvanian Naco Formation in central Arizona. Spiraclavus nacoensis n. gen. and sp. is similar to Lepidodiscus laudoni (Bassler, 1936) and Discocystis kaskaskiensis (Hall, 1858), but differs in the direction of ambulacral curvature and in the number and arrangement of ambulacral cover plates. Numerous well-preserved, disarticulated plates allow a full description of plate morphologies from various parts of the theca. The entire oral surface is rigidly constructed of tessellate plates. Interlocking serrate sutures between successive floor plates add strength. Plate sutures in the flexible and telescoping portions of the theca (recumbent zone and pedunculate zone, respectively) are beveled, allowing considerable imbrication and potential for thecal extension.

The associated fauna indicates that the unit containing the edrioasteroids was deposited on an offshore, subtidal, marine carbonate shelf with occasional siliciclastic influxes. The specimens of Spiraclavus nacoensis were buried by siliciclastics, probably during storm events.

Two cupulocrinids, Cupulocrinus crossmani n. sp. and Praecupulocrinus conjugans (Billings) n. gen., are known from the Middle Ordovician (Galena Group, Dunleith Formation) of northern Iowa and southern Minnesota. Various morphologic and ontogenetic features demonstrate that Praecupulocrinus is more primitive than Cupulocrinus. The two species commonly occur together. In addition, both taxa coexisted at similar levels with stem lengths ranging from about 1.5 cm in juveniles to 15 cm in adults. Relatively complete growth sequences illustrate growth and variation and show how two related crinoids subdivided feeding niches. The crown volume provides a satisfactory surrogate variable for the size of the animal. The food-gathering system of the cupulocrinids is mainly augmented by the addition of new plates at the ends of the arms. The number of plates in the arms and the arm length exhibit positive allometry relative to crown volume, largely due to development of new branches at the arm tips. The food-gathering capacity equals the number of food-catching tube-feet multiplied by the average width of the food grooves. Food-gathering capacity is also positively allometric with respect to crown volume and the amount of tissue that must be supplied with food. Consequently, the ratio of food-gathering capacity:crown volume is either constant or declines slightly with increasing size and age. The food groove width increases throughout ontogeny so adult crinoids ate larger food particles than juveniles. Praecupulocrinus conjugans (Billings) n. gen. has more narrow food grooves than Cupulocrinus crossmani n. sp. of comparable size and age, which suggests niche differentiation based on food-particle size. The arm and tube-foot geometry indicates that both cupulocrinids utilized the same type of suspension feeding.

The morphology of the anal sac and the lack of “patelloid” processes in the arms indicate that Cupulocrinus sepulchrum Ramsbottom from the Upper Ordovician of Scotland belongs to Dendrocrinus.

Aspects of functional morphology are examined and lifestyles proposed for seven exceptionally well-preserved crinoids from the Middle Ordovician Lebanon Limestone, Middle Tennessee. Potential ranges of motion are based on plate shapes, articular surfaces of attachment, and feeding structures. This diverse group of crinoids includes disparid inadunates (Columbicrinus crassus and Tryssocrinus endotomitus), a hybocrinid (Hybocrinus bilateralis), reteocrinids (Reteocrinus polki and R. variabilicaulis), and rhodocrinitid camerates (Archaeocrinus snyderi and Gustabilicrinus plektanikaulos). Using attachment structures as the basis, these crinoids can be divided into two groups: encrusters and commensals. Encrusters are the most diverse and include all taxa except the rhodocrinitids. They have a small discoidal holdfast and xenomorphic column. Proxistele-mesisteles were holomeric or pentameric. Flexure potential of this region of the column in disparids was increased by wider ligament gaps at nodal-internodal articulations; in other taxa flexure was enhanced by increasing the frequency of columnals. Short dististeles are polymeric or a plate mosaic. This region functioned as a resilient buffer between the mesistele and holdfast. Columns as a whole had moderate flexure potential. Feeding-structure design was varied, although all but Hybocrinus bilateralis had pinnulate or nonpinnulate parabolic filtration fans. Hybocrinus bilateralis had atomous arms arrayed in a bilaterally symmetrical pattern; the symmetry plane was oriented parallel to prevailing currents. Commensals in the Lebanon are the rhodocrinitids. Their attachment structures are characterized by a long distally tapering column terminating in a coil. Densely pinnulate arms formed a well-developed parabolic filtration fan.

Encrusters were limited to hardgrounds or skeletal substrata. Commensals were more opportunistic, utilizing a variety of substrates, and they were widespread in Lebanon subenvironments including those with both soft and hard seafloors. Lebanon hardground assemblages are characterized by high diversity, particularly among crinoids and bryozoans. They are strikingly tiered according to elevation above the seafloor (and probably additionally by feeding limitations). This assemblage was the result of longterm coevolution in association with hardgrounds.

Ontogenetic development of the column of encrusting crinoids indicates that the evolution of holomeric columnals occurred through a simpler sequence than previously proposed and need not have included gradual alignment of offset pentameres as intermediate steps. Columnals evolved from a poorly organized plate mosaic through a polymeric stage.

A sequence of unusual vertical tubes, arranged in multiple groups, and each tube several meters high occurs in the Middlesboro Member of the Lee Formation (Lower Pennsylvanian). These structures are controversial with various interpretations suggesting either plant or animal origin. Observations supporting a plant origin include: 1) numerous C- and D-shaped, and multichambered tube cross sections are similar to fern and seed fern structures, 2) numerous membrane relicts loosely enclosing the tubes are similar to fern and seed fern tissues, 3) microscopic bundles are observed in cross-sectional thin sections, 4) presence of carbonaceous material and reported fecal pellets over a vertical distance in excess of 5 m are consistent with deteriorating plant material, not escape structures, 5) tubes are composed of casts and molds, but lack spreite or other features typical of escape structures, 6) tubes occur in clusters about one meter in diameter and are associated with coaly material at their base, which suggests that the clusters represent trees, 7) other trace fossils are absent in the enclosing sandstone, 8) tubes branch upward, which is a common structure in plants but unlikely in escape structures, 9) a coalified root structure was found at the base of the sandstone, and 10) all the tubes extend from the bottom of the sandstone to the top. The probability of burrowing animals escaping through as much as 8 m of sand with 100 percent survivorship is low.

The structures may represent a stand of pteridosperms with each “tree” approximately 1–1.5 m in diameter. The individual pipe-organ structures represent aerial stems, shoots, and adventitious roots; each cluster of pipe-organ structures represents a single tree.

Based upon sedimentologic features such as presence of 1) channel form, 2) scoured base, and 3) fining-upward sequence, we interpret the sandstone containing the pipe-organ structures to have been deposited in a sandy fluvial or tidal channel. The unidirectional cross-bed dips, poor sorting, occurrence only of very restrictive fauna and terrestrial flora, position of the sandstone above a possible floodplain facies, and lack of characteristic tidal structures suggest that the sandstone is more probably a sandy fluvial channel that may have minor tidal influence.

A fossil counterpart to ths extant marine noncalcareous green algal genus Caulerpa was recovered from Permian (Wolfcampian) marine sediments of the Palo Duro Basin, a part of the larger Permian Basin, West Texas. These fossil algal remains were recognized in core from the Department of Energy/Stone and Webster Engineering Corporation No. 1 Zeech well (Figure 1). The fossil form is described and compared to a morphologically similar extant species of Caulerpa. The geologic setting of the Palo Duro Basin is also briefly described as is the environment in which the modern algal genus Caulerpa lives.

Stagodontid marsupials were a common component of late Mesozoic vertebrate faunas of the Western Interior of North America and were among the largest mammals that coexisted with Late Cretaceous dinosaurs. Two genera have been described, Didelphodon and Eodelphis; three if Pariadens (?Stagodontidae) from the Cenomanian of Utah (Cifelli and Eaton, 1987) is included. The dental arcade of stagodontids is notable for the presence of bulbous premolars, each with a massive main cusp and a large accessory lobe. The most complete stagodontid material consists of a maxillary fragment and a few nearly complete dentaries referred to Didelphodon (see Clemens, 1968, 1973; Fox and Naylor, 1986). However, the configuration of the anterior upper dentition of Didelphodon and other stagodontids is uncertain because of the lack of specimens preserving this portion of the skull. Thus, based on isolated teeth, upper premolars of Didelphodon have been interpreted to have been oriented with their accessory lobes either on their labial (Clemens, 1966) or lingual (Clemens, 1968; Lillegraven, 1969; Archibald, 1982; Fox and Naylor, 1986) sides.

M. Griffin (Division Paleozoologia Invertebrados, Museo de la Plata, Argentin) and P. Bouchet (Muséum national d'Histoire naturelle, Paris) have kindly brought to my attention the fact that the genus name Taniella Kase (1990, p. 573; type species Taniella japonica Kase, 1990) is preoccupied by Taniella Finlay and Marwick, 1937, p. 48 (type species Natica notocenica Finlay, 1924). Consequently, a new name, Tanimasanoria, is proposed as a replacement for Taniella Kase, 1990. It is named in honor of Masanori Tani, for years of collecting the Izumi gastropods.

Following the publication of papers by Bergström and Sweet (1966) and Schopf (1966), a gradual shift from the use of discrete element taxonomy to multielement taxonomy has occurred in describing conodonts. Although most workers now apply multielement taxonomy wherever possible, systematics have not been updated for many of the conodont faunas described earlier, and as a result the use of multielement taxonomy still is far from universal.