Fossils can inform the study of modern ecosystems by showing how species interactions in ancient communities compare with those today and how extinction is selective not only with respect to species but also with respect to entire modes of life. We studied the life habits and pattern of occurrence of the barnacle Chesaconcavus chesapeakensis Zullo, 1992 on the shells of the gastropod Conradconfusus parilis (Conrad) and the bivalve Chesapecten santamaria (Tucker) from Chancellor’s Point in the Windmill Point Member of the St. Mary’s Formation (late Miocene, Tortonian) of Maryland. Using several criteria, we show that the barnacle occupied living hosts only. The 59% incidence of the barnacle on Conradconfusus parilis is high compared to known living associations between barnacles and gastropods. Although Conradconfusus parilis with and without barnacles do not differ in size, suggesting that the barnacle had little effect on this gastropod, there is some indication that Chesapecten santamaria with barnacles are somewhat smaller than those without and may therefore have been adversely affected by the presence of barnacles. On the basis of morphology and the low (15%) incidence of repaired scars, Conradconfusus parilis was a predator that did not use its shell lip to subdue prey. No ecological equivalents of Conradconfusus and Chesaconcavus have existed in the temperate northwestern Atlantic between Cape Cod and Cape Hatteras for the past three million years.

A new method of analyzing the internal shell morphology (including the complete brachidium of internal molds) of articulated brachiopod shells through the use of serial sections and digital three-dimensional reconstruction is presented. The method introduced is essential for the study of internal shell structures such as brachidia, or cardinalia, if computed tomography (CT) is not suitable or if a CT scanner is not available. A new species of Athyris from Givetian beds of Northwest Africa was selected to exemplify this method. To compare this species with figured serial sections in the literature, two-dimensional drawings of grinding surfaces are provided. Athyris africana n. sp. is only preserved as internal molds of articulated specimens. The new species is included in the evolutionary lineage of the group around Athyris concentrica. The faunal assemblage of A. africana n. sp. shows affinities to Western European and North American brachiopod faunas.

Turritelline Gastropods (family Turritellidae, subfamily Turritellinae; sensu Marwick, 1957) are common components of many Cretaceous to Recent benthic marine assemblages worldwide. They are frequently the dominant or even the sole macrofossil in such assemblages (Allmon, 1988), termed “turritelline- dominated assemblages” (TDAs; Allmon and Knight, 1993). They are defined as macrofaunal assemblages in which turritelline gastropods: 1) comprise either at least 20% of the total actual or estimated biomass or at least 20% of the macroscopic individuals in the assemblage, and 2) are at least twice as abundant as any other macroscopic species in the assemblage (Allmon, 2007). TDAs have been widely reported from siliciclastic and carbonate sediments of the U.S. Gulf and Atlantic Coastal Plains, but turritelline-dominated limestones (sometimes referred to as “turritella limestone” or “turritella rock”) appear to be limited to the Cretaceous and Paleogene (Allmon and Knight, 1993; Allmon, 2007; Allmon and Cohen, 2007).

Analyses of shell shape variation in epifaunal and semi-infaunal myalinids from the LaSalle “cyclothem” attest to the extensive shape plasticity of some Late Pennsylvanian myalinids. Mean shell shapes differ significantly within and among species across three nearshore facies. Discriminant analyses of Fourier biometric data categorized by taxonomic, populational (habitat), life-mode, and “multi-species habitat assemblage”” discriminant groups reveal patterns of shape change and variation across an inferred environmental stress gradient in addition to taxonomic and life-mode shape differences. Fourier harmonic data are good indicators of shape differences between epifaunal and semi-infaunal life modes. Mean shapes of epifaunal species vary among habitats. Within-habitat shell shape convergence occurred between Myalina glossoidea and M. (Orthomyalina) slocomi. Interpopulational shape divergence occurred among all populations of M. (Orthomyalina) slocomi, M. glossoidea, and M. wyomingensis. Within-species variation among habitats produced significant mean shape differences among each of three “multi-species habitat assemblages.” Results indicate that a portion of the variation is of ecophenotypic origin.

Mean interspecific shape differences reflect internal functional organization and life modes. Intraspecific shape differences among epifaunal species could reflect physical and biotic habitat variables. Several harmonic amplitudes vary in concert with inferred environmental variation among habitats. Although biologic interpretation of harmonic data is problematic, parallel trends in fifth harmonic amplitudes of epifaunal species mirror inferred differences in water turbulence among habitats and could reflect shape variation related to byssal attachment.

Stress gradient trends in intraspecific shape variability cannot be collectively explained by either of the antithetical stability-diversity-variation hypotheses. Each species exhibits a different nonmonotonic trend. Maximal levels of intraspecific variation within each species occurred within different habitats. Within-species differences in levels of variation could result from genetic variation among populations as well as ecophenotypic influences. Comparative studies of ontogenetic shape change between valves of individuals, among individuals, and among populations are necessary to determine the relative influence of environmental variables on shape variation and evolutionary significance of phenotypic plasticity.

Extinct Hydrochoerinae traditionally included within ‘Cardiomyinae’ (Cavioidea, Caviidae) are caviomorph rodents well represented in the late Miocene to late Pliocene of Argentina, but their paleobiology has received little scientific attention. The postcranium of these rodents is poorly known and has not been considered in morphofunctional or systematic studies. Here, we provide the first description of the postcranium of the basal hydrochoerine Cardiomys Ameghino, 1885, based on a well-preserved specimen from the late Miocene of Central Argentina, and evaluate its paleobiological and systematic implications. A morphofunctional study and a character mapping analysis were performed. We concluded that most of its postcranial features are neither adaptations to a specialized cursoriality, as in some extant cavioids, nor major modifications associated with swimming, as in extant capybaras. Cardiomys exhibits several features (high humeral distal articular surface, perforated olecranon fossa, proximal portion of radius cranially located with respect to the ulna, subrectangular-shaped radial head with flattened ulnar facet, calcaneocuboid joint distally located with respect to the astragalonavicular joint) that allow us to interpret it as an ambulatory caviid. Among cavioids, some features of Cardiomys are more similar to those of Hydrochoerus Brisson, 1762 (lateral coronoid process reduced, humeral capitular tail well differentiated, capitular tail facet of the radial head well developed and relatively short craniodistally, plantar process of the navicular massive and short). Other postcranial features (relatively longer and more gracile third metatarsal and phalanges, straight caudal border of the ulna) suggest that Cardiomys would have been a generalized hydrochoerine, as also indicated by its dental and cranial characters.

Paromomyidae are one of several families of plesiadapiforms that flourished during the Paleocene in North America soon after the extinction of non-avian dinosaurs some 66 million years ago. Although they are often among the best-represented plesiadapiforms in mammalian faunas in both North America and Europe, the early history of paromomyids is poorly understood, and their fossil record at higher latitudes is comparatively depauperate. We report here on the discovery of two new species of paromomyids from Paleocene deposits in southwestern Alberta: Edworthia greggi new species is the second known species of the basal paromomyid Edworthia Fox, Scott, and Rankin, 2010 whereas Ignacius glenbowensis new species is among the most abundantly represented species of Ignacius Matthew and Granger, 1921. These new discoveries document, for the first time, parts of the upper dentition of Edworthia, and the new species of Ignacius represents the first new, pre-Clarkforkian species of the genus to be described in nearly 100 years. A comprehensive phylogenetic analysis of nearly all known paromomyid taxa (including the new species described herein) recovered both species of Edworthia near the base of the paromomyid tree in a polytomy with Paromomys depressidens Gidley, 1923 and a paraphyletic Ignacius. The new paromomyids from Alberta not only increase the known taxonomic diversity of Edworthia and Ignacius but also add significantly to knowledge of the dental anatomy of these poorly known genera and further add to a uniquely Canadian complement of Paleocene plesiadapiforms.

UUID: http://zoobank.org/a2f31cfe-09b9-4168-b09f-9d0c3d0af342

The lower-middle Hetang Formation (Cambrian Stage 2–3) deposited in slope-basinal facies in South China is well known for its preservation of the earliest articulated sponge fossils, providing an important taphonomic window into the Cambrian Explosion. However, the Hetang Formation also hosts a number of problematic animal fossils that have not been systematically described. This omission results in an incomplete picture of the Hetang biota and limits its contribution to the understanding of the early evolution of animals. Here we describe a new animal taxon, Cambrowania ovata Tang and Xiao, new genus new species, from the middle Hetang Formation in the Lantian area of southern Anhui Province, South China. Specimens are preserved as carbonaceous compressions, although some are secondarily mineralized. A comprehensive analysis using reflected light microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and micro-CT reveals that the new species is characterized by a spheroidal to fusoidal truss-like structure consisting of rafter-like crossbars, some of which are secondarily baritized and may have been internally hollow. Some specimens have aperture-like structures that are broadly similar to oscula of sponges, whereas others show evidence of a medial split reminiscent of gaping carapaces. While the phylogenetic affinity of Cambrowania ovata Tang and Xiao, n. gen. n. sp. remains problematic, we propose that it may represent carapaces of bivalved arthropods or more likely sponges in early life stages. Along with other problematic metazoan fossils such as hyolithids and sphenothallids, Cambrowania ovata Tang and Xiao, n. gen. n. sp. adds to the diversity of the sponge-dominated Hetang biota in an early Cambrian deepwater slope-basinal environment.

UUID: http://zoobank.org/44de9472-7e3f-42d1-9554-7b3434df91d9

A late Pliocene (3.36–3.06 Ma) exposure of the Tangahoe Formation on the North Island of New Zealand preserves close fossil relatives of many extant seabird clades. Here, we report an extinct member of the little penguin (Eudyptula Bonaparte, 1856) lineage from the Tangahoe Formation—the smallest extinct crown penguin yet known. Eudyptula wilsonae n. sp. is based on the nearly complete skulls of an adult and a fledged but immature individual. Both skulls show more slender proportions than modern little penguins and precede genome-derived estimates for the divergence between Eudyptula minor minor Forster, 1781 (endemic to New Zealand) and Eudyptula m. novaehollandiae Stephens, 1826 (native to Australia and recently established in New Zealand). This raises the possibility that the fossil taxon represents a lineage directly ancestral to extant little penguins. Our results support a Zealandian origin for little penguins, with subsequent Pleistocene dispersal to Australia and a more recent Holocene range expansion of Eudyptula m. novaehollandiae back into New Zealand.

UUID: https://zoobank.org/a415f70a-e441-4920-85e0-75f6457577ea

Retiolitid graptolites are a very common component in Silurian graptolite faunas of the Canadian Arctic, both in flattened form on shale surfaces and in uncompressed form in limestone concretions found in the enclosing shales (Lenz and Melchin, 1987). Upper Wenlock and Ludlow rocks are particularly prolific, having yielded about 20 species of retiolitids to date. One of the collections made during the summer of 1991 was a single piece of talus-derived shale containing 10 complete and slightly fragmented retiolitids. These specimens are morphologically unique, and their description is the purpose of this note.

A small (1.2 m) columnar carbonate mound in shaley strata equivalent to the Hartselle Sandstone (lower Serpukhovian) near Woodville, northeastern Alabama, was built by a consortium of species unlike those of other Carboniferous mounds in the southeastern United States. The mound contains a new problematic microencruster, Aphralysia anfracta new species, along with encrusting bryozoans (Fistulipora M'Coy, 1849), nonskeletal microbes, and other microencrusters, including Aphralysia capriorae Mamet and Roux, 1975, in a carbonate mud matrix. Mound cavities are filled with three generations of carbonate and siliciclastic sediment. Other biotic constituents of the mound include oncoids, sponges (including Pileospongia Rigby, Keyes, and Horowitz, 1979), gastropods, crinoids, a tabulate coral, and coenobionts, including coccoid calcimicrobes. The mound biota, especially the microencrusters, is dramatically different from those of other Serpukhovian mounds that have been described from Alabama (made by various consortia of rugose corals, fenestrate bryozoans, crinoids, sponges, and nonskeletal microbes). Indeed, the Woodville mound extends the range of the lower Carboniferous encruster Aphralysia Garwood, 1914 to North America.

UUID: http://zoobank.org/d3988875-a7fb-4382-bd14-b17c083d87ad

The Clypeastroid echinoid Fibularia texana (Twitchell) has been reported in the literature from only two localities. Twitchell (Clark and Twitchell, 1915) reported that the holotype was collected by T. H. Aldrich from an unspecified locality in Lee County, Texas, from the “Lower Claiborne,” Middle Eocene. Cooke (1942, 1959) reported F. texana from the Weches Formation, lower Claiborne, in San Augustine County, Texas (see Eargle, 1968, for stratigraphic nomenclature). He intimated that the type occurrence in Lee County was also from the Weches Formation. I have recently collected F. texana from the fossiliferous Cook Mountain (upper Claiborne) deposits exposed along Elm Creek in Lee County. Evidence is presented to show that Aldrich's original collection was from Cook Mountain exposures along Elm Creek, and this is designated as the type locality.

A large-diameter coring device was designed to recover plant litter in fluvial sediments as part of a taphonomic study of plant deposition in a modern river system. The corer was used to retrieve unconsolidated sediments from shallow (< 1.5 m) water, either from a boat or from the riverbank, and was designed to be transportable for use in remote reaches of tropical rivers. The device is operable by a single person, easily repaired, and rugged.

The Actinocrinitidae were among the most abundant crinoids worldwide during the Lower Mississippian. Recent systematic revisions of the family allow a revised genus- and species-level understanding of these crinoids globally and a more precise means by which to understand the temporal and facies distribution of genera and species in this important Mississippian family. Two genera with a total of five species of Actinocrinitidae (and five additional forms left in open nomenclature) are recognized from the Fort Payne Formation, including Actinocrinites jugosus (Hall, 1859), Actinocrinites spp. indeterminate, Thinocrinus gibsoni (Miller and Gurley, 1893), Thinocrinus lowei (Hall, 1858), Thinocrinus probolos (Ausich and Kammer, 1991), Thinocrinus akanthos new species, Thinocrinus sp. aff. T. gibsoni, Thinocrinus spp. indeterminate, and two taxa recognized as only Actinocrinitidae genus and species indeterminate. Actinocrinites tripus Ehlers and Kesling, 1963 is recognized as a junior synonym of Thinocrinus gibsoni. Thinocrinus, rather than Actinocrinites as previously thought, is the dominant Fort Payne Formation actinocrinitid. Fort Payne Formation carbonate buildup facies (wackestone buildups and crinoidal packstone buildups) each have characteristic species of Thinocrinus. Actinocrinites is relatively rare in the Fort Payne Formation, but occurs preferentially in crinoidal packstone buildups.

Recently discovered specimens of the marsupial Herpetotherium merriami (Stock and Furlong, 1922) from the John Day Formation, Oregon, are described. The species was previously known only from a single (type) specimen. These additional specimens have allowed for a revised diagnosis of the species based on the presence of an additional stylar cusp on the upper molars, as well as the relative size of the stylar cusps. This new material also allows for an examination of the variability within the species and establishes a time range for the species, which extends through most of the Arikareean (late Oligocene: Ar1–Ar3: late Rupelian-Aquitanian). Herpetotherium merriami is distinct within the genus because it is among the larger of the species, but one of the latest occurring, whereas the general pattern of the genus is a reduction in size through time.

Solitary species of Heliophyllum are the most common form of the genus but branching and massive colonies do occur, especially in Middle Devonian strata of eastern North America. Heliophyllum delicatum n. sp. offsets laterally and has a dendroid, broad bushy growth form. The species is known only from western and west-central New York and appears to be limited to the lower part of the Deep Run Shale Member of the Moscow Formation (middle Givetian); specimens are common within this restricted geographic and stratigraphic range. The skeleton of H. delicatum was poorly designed for the common coral environments of the Devonian, but seems to have been well adapted to muddy, carbonate-poor conditions where its thin skeletal elements required less calcium carbonate and its unsupported branches were not subject to vigorous water movement.

Heliophyllum stewarti n. sp. is based on a single specimen from the Tenmile Creek Dolomite (middle Givetian) in northwestern Ohio. The colony is phaceloid but each branch is an astreoid cluster without walls between individual corallites. In addition, the apparent protocorallite is turbinate with a larger diameter than any of the ceratoid offsets although offset lengths are several times that of the protocorallite.

Bairdiid ostracodes are commonly present in the Pennsylvanian marine zones in the Appalachian basin. Thirty-one taxa are recognized representing the genera Bairdia McCoy, 1844; Orthobairdia Sohn, 1960; Cryptobairdia Sohn, 1960; Rectobairdia Sohn, 1960; Bairdiolites Croneis and Gale, 1939; and Bairdiacypris Bradfield, 1935. Two questionable bairdiid genera, Entmema new genus and Hastacypris Croneis and Gutke, 1939, are included. Seven new taxa, Bairdia cuspidis, Rectobairdia absidata, R. apiculata, R. levis, R. sohni, Entmena distenta, and Hastacypris acutula, are described. Fabalicypris Cooper, 1946, is considered a junior synonym of Bairdiacypris Bradfield, 1935.

The diversity of bairdiids is significantly lower in the Appalachian basin than in the Eastern Interior and Western Interior basins.

Colonial rugose corals are uncommon in Pennsylvanian rocks in North America and until now the only massive form known from rocks of this age south of the Arctic is an undescribed species of Petalaxis reported by Sutherland (1985) from Morrowan rocks in Oklahoma, Texas, and New Mexico. This report concerns a second species of Petalaxis recovered from Desmoinesian rocks immediately west of Death Valley, California. Although only a single colony has been found, it is profoundly different from all other described species of this genus and is significant from the standpoint of its presence during a very long time span when there was an apparent dearth of massive rugose corals in most of North America.

More than 70 species of Paleozoic articulate brachiopods with color patterns have been reported in the literature (see Blodgett et al., 1983, table 1; Table 1). The majority of them are Devonian terebratuloid brachiopods. Twenty-two Permian brachiopod species were previously described as retaining color patterns. Most of them belong to Dielasma and have radial to subradial color patterns. Here we report a smooth spiriferid, Martinia? sp., with well-preserved radial color bands from Late Permian rocks of South China.

Newly discovered mandibles and lower dentition of the middle Eocene rodent Thisbemys brevicrista from the Green River Basin, Wyoming, are the basis for a species re-diagnosis. Previously, only the upper dentition and a partial maxilla of T. brevicrista were known from Br3. New specimens from Br2 now include the lower molars, additional upper molars, and maxillary fragments including a partial zygomatic arch that preserves the relationship of the arch to the first upper molar. In addition, the presence of T. brevicrista at Br2 documents the co-existence of T. brevicrista with T. perditus, T. nini, T. plicatus, and T. corrugatus. Formerly, the latter two species were differentiated primarily using stratigraphy. Now, morphology and size can also be used. Thisbemys brevicrista is intermediate in size between T. plicatus and T. corrugatus, and can readily be distinguished from these species based on unique features of the upper and lower molars, which include an additional loph on the two anterior upper molars and a complete metalophid on m1-3. The original type specimen of T. brevicrista appears to be lost, thus a neotype is designated as part of the re-diagnosis. Discovery and description of the lower dentition and mandibles of T. brevicrista clarifies the alpha taxonomy of this species, and increases its utility for studies of phylogenetic relationships and for documenting Eocene mammalian diversity patterns.