The oligopygoid echinoid Haimea bajasurensis n. sp. is described from middle lower Eocene (”Capay Stage”) shallow-marine sandstones in the middle part of the Bateque Formation and shallow-marine limestones in the upper part of the Tepetate Formation, Baja California Sur, Mexico. The new species is both the earliest and the westernmost oligopygoid, and the first occurrence of Haimea in North America.

During the 1991 ostracodologists' symposium in Australia, I heard a young man in the seat across the aisle tell his companion, “I hope that my new species will never be placed in synonymy.” I turned to him and explained that there is neither shame nor crime in having a species placed in synonymy by another scientist.

The purpose of this note is to point out the similarities between Protosalvinia (Foerstia) and Sidetes (Spathiocaris) and to discuss characters that can be used to distinguish the two taxa. Protosalvinia Clarke, 1885 (Figure 1.1-1.4), also commonly referred to by the junior subjective synonym Foerstia, is a plant fossil that is frequently noted as occurring in Upper Devonian black shale sequences of North America. This taxon has been of great interest to stratigraphers, paleoecologists, plant taxonomists, and plant morphologists over the years (see, for example, Winslow, 1962, p. 7, p. 22, fig. 3; Barron and Ettensohn, 1981, p. 30-31; Matthews, 1983; and Romankiw et al., 1988). Most workers in recent years have considered Protosalvinia to be a marine alga, but there is also evidence for a land plant affinity (Romankiw et al., 1988).

It has long been considered that all monograptids have theca 1 originating from a primary porus in the sicula (i.e., sinus and lacuna stages; Bulman, 1970). The major basis for this assumption has been studies of Late Silurian monograptid species such as Saetograptus chimaera (Barrande), Pristiograptus bohemicus (Barrande), and Pristiograptus dubius (Suess) (e.g., Eisenack, 1942; Walker, 1953; Urbanek, 1958). That all monograptids possessed this type of development was not questioned due to the lack of well-preserved, early monograptid specimens clearly showing the sicula–theca 1 relationship. Hutt et al. (1970) described Monograptus gregarius Lapworth, from the gregarius Zone, as having theca 1 originating through a primary porus (Hutt et al., 1970; Rickards and Hutt, 1970, referred to this as a “primary notch” although, according to Bulman, 1970, p. V11, the notch corresponds only to the sinus stage). Their figures of these specimens, however, do not unequivocally confirm its presence (Hutt et al., 1970, p. 14, Pl. 3, figs. 65, 67). Rickards and Hutt (1970) alluded to the possible presence of a primary porus in Atavograptus ceryx (Rickards and Hutt) from the persculptus Zone, but could not determine its existence with certainty. Mitchell (1987) was the first to question the presence of this mode of development of theca 1 in relation to the origin of the monograptids. He proposed, however, that the development of the fully uniserial rhabdosome was coincident with a change in both the sicular structure (the sinus and lacuna stages) and the early ontogeny of theca 1. He suggested that the sinus and lacuna stages represented a homologue of the hooded foramen seen in the th 11 protheca of some Pattern H species, from which th 12 emerges and that, in the uniserial monograptids, this feature is accelerated in the astogenetic sequence, appearing in the metasicular ontogeny rather than that of the first theca. He pointed out that this hypothesis could only be tested once suitable, isolated specimens of earliest monograptids could be studied to see if the sinus and lacuna stages were, indeed, coincident with the achievement of a fully uniserial rhabdosome. New evidence from isolated, early monograptid material allows us to test Mitchell's theory on monograptid origin.

Beautifully preserved, isolated and uncompressed plectograptine graptolites from the uppermost Wenlock “Pristiograptus” ludensis Biozone and the lower Ludlow Lobograptus progenitor Biozone are described from the Arctic Islands. Described species comprise Agastograptus robustus Obut and Zaslavskaya from the ludensis and progenitor zones; Agastograptus sp., Gothograptus chainos Lenz, and Plectograptus (Sokolovograptus?) sp., from the ludensis Zone; and Holoretiolites (Balticograptus) erraticus (Eisenack) from the progenitor Zone. The dozens of specimens of A. robustus from one locality are covered with almost continuous periderm and interthecal tissue, a feature rarely seen in plectograptines.

Actinomycetes are Gram-positive prokaryotes that tend to form branching and fragmenting filaments, which in some groups form a sizable mycelium. They make up a large and important part of modern terrestrial microfloras but are not known extensively as fossils, although they have a long fossil history. Actinomycete-like fossils appear several times in the Precambrian: in the middle Precambrian Gowganda Formation of Ontario (Jackson, 1967), in the 2.0 Ga Gunflint Chert of Ontario (Lanier, 1987), and possibly in a lichen-like symbiosis in the 2.8 Ga Witwatersrand rocks of South Africa (Hallbauer and Van Warmelo, 1974), among others. Direct fossil evidence of actinomycetes is very rare in the Phanerozoic, and some “fossil” actinomycetes may be later contaminants (Knoll, 1977; Smoot and Taylor, 1983). Hyphae identified as actinomycetes are known from rod-like bodies identified as nematodes inside a decaying scorpion from the lower Carboniferous of Scotland (Stoermer, 1964), and from the interior of fern phloem cells from the Pennsylvanian (Smoot and Taylor, 1983). Unmineralized Actinomyces-like cells are known from calcite in bituminous lake-bed sediments from the early Cretaceous of Nevada (Bradley, 1963), and similar, poorly preserved fossils of a form called Actinomycites have been reported from the Jurassic of Scotland (Ellis, 1915). Actinorhizal nodules, formed by actinomycetes symbiotic with plant roots, have been described from the late Pleistocene (Baker and Miller, 1980).

Comparisons between Phycosiphon incertum Fischer-Ooster (1858) and Anconichnus horizontalis Kern (1978) show that these two monotypic ichnogenera do not differ significantly in geometry, size, sediment fill, and environmental occurrence. Therefore, taxonomic priority has to be given to Phycosiphon and Anconichnus becomes a subjective junior synonym. The trace fossil is a small, highly lobed spreite structure produced by a zoned backfill consisting of a pale mantle and dark core. In a few cases, a meniscate structure is visible in the core. The spreite sediment is an extension of the mantle material; it commonly is poorly visible. The spreite-producing behavior may be locally interrupted, leaving a single tube of backfill. The spatial arrangement of the trace fossils seems to depend on the host sediment; in muddy and homogeneous material the lobes tend to be oriented randomly, including vertically, whereas in laminated sand and silty sediments they tend to lie parallel to bedding. This latter orientation is exaggerated by compaction. Textural differences between host sediment and spreite or mantle may be subtle and not always evident. Observations in modern sediments are in agreement with the type material of both ichnogenera.

Between the years 1940 and 1968 Schultz and Falkenbach published eight papers revising the taxonomy of oreodonts (Merycoidodontidae). Although these papers suffer from many difficulties, including the oversplitting of taxa and the citation of plastically deformed features as diagnostic characters (M. S. Stevens, personal commun.), they remain the primary systematic work on oreodonts produced this century.

Several unsilicified gastropod specimens were collected by John B. Mertie, Jr., on July 13, 1941, during a boat traverse along the Porcupine River of east-central Alaska. The specimens were originally deposited in the Ulrich (Cambrian and Ordovician) stratigraphic collections of the U.S. Geological Survey at the National Museum of Natural History, Washington, D.C. The collection contains one specimen of Palliseria and three specimens of Maclurites, all of which are broken from the limestone. Despite the lack of much of the shell material, they are easily identified as to genus. One specimen identified as Palliseria is particularly significant.

Predatory drillholes (boreholes) are known from fossils as old as the late Precambrian (Bengtson and Zhao, 1992). The presence of predatory drillholes has been documented in a large number of shelly invertebrates including bivalves, gastropods, scaphopods, crabs, ostracodes, brachiopods, and many others (e.g., Sohl, 1969; Bishop, 1975; Bromley, 1981; Vermeij, 1987; Kabat, 1990; and references therein). We document here, for the first time, a drillhole in a lingulid brachiopod.

Cup nodes on Lochriea commutata Pa elements bear microsculpture fields composed of polygonal microsculpture. As Pa elements grow larger, the cup nodes and their microsculpture fields increase in size during early to middle growth. With subsequent growth, cup nodes may broaden transversely, split, fuse, or cease to broaden; similarly, their microsculpture fields may increase in size, split, or disappear as the element gets larger. The loss of microsculpture fields results in the loss of polygonal microsculpture.

The presence of polygonal microsculpture on the cup nodes of Pa elements of the holotype of Lochriea montanaensis Scott, 1942, on topotype Pa elements of L. commutata (Branson and Mehl, 1941), as well as on L. commutata Pa elements from diverse localities, suggests that this micromorphological feature cannot be used to distinguish them. Instead, these similarities support the practice of treating L. montanaensis as a junior synonym of L. commutata. The fact that cup node, microsculpture field, and polygonal microsculpture development are closely related to growth and ontogeny and are variable in the larger growth stages suggests that these morphological features should be used with caution in taxonomy. This lack of reliability contrasts with the taxonomic utility of pustulose micrornamentation on the homeomorphic Pa elements of the Permian genus Sweetognathus.

McRoberts (1992, figs. 4.13, 4.14, 6.8) illustrated the shell microstructure of late Triassic Gryphaea (Gryphaea) arcuataeformis Kiparisova, 1936, and Gryphaea (Gryphaea) nevadensis McRoberts, 1992. McRoberts (1992, p. 33) described the left valve of G. arcuataeformis as showing “neomorphosed calcite with multiple laminae of ?prismatic structure perpendicular to [the] outer shell surface ….” He described the left valve of G. nevadensis as consisting of two distinct layers of neomorphosed calcite:“…an outer layer with ?prismatic structure occasionally with bands of dark material (?micritic matrix), and a much thinner inner layer with ?cross-foliated structure ….” Subsequent study has shown these microstructural diagnoses to be inaccurate. They are revised as follows.

Three new species and one new subspecies of Streptognathodus were discovered during systematic stratigraphic study of conodonts from Virgilian cyclothems of Kansas. Streptognathodus bitteri n. sp. characterizes faunas from the middle of the Plattsmouth Limestone but ranges into the upper Wabaunsee Group. Streptognathodus brownvillensis n. sp. is restricted to the Brownville Limestone. Streptognathodus holtensis n. sp. occurs in the Holt Shale, as well as the Church, Burlingame, Wakarusa, and Elmont Limestones. A new subspecies of S. pawhuskaensis (S. pawhuskaensis deflectus) was recovered from the lower half of the Shawnee Group.

The marine Triassic rocks of Nevada are well known for their ichthyosaur finds, and a number of new genera and species were described from this state. Based on a few vertebrae, Leidy (1868) erected a new Middle Triassic ichthyosaur genus, Cymbospondylys, with two species, C. petrinus and C. piscosus. The type material of C. petrinus came from the Prida Formation of the southern Humboldt Range, and that of C. piscosus from the Favret Formation of the New Pass Range.