Several specimens of Dickinsonia cf. D. menneri, originating from a single burial event at the Lyamtsa locality of the late Ediacaran (Vendian) in the southeastern White Sea area, Russia, represent deviations from normal morphology: a reduction in the total length of the body; the loss of portions of the body; various deformations of the transverse elements, called isomers; and splitting of the longitudinal axis with the formation of two posterior ends. It is assumed that these deformations were formed as a result of non-lethal damage, which occurred long before the burial event, and the response of Dickinsonia to them. The progress of the regeneration process at the damaged areas, and especially its deviations, indicates that the growth zone was located at the posterior end of the Dickinsonia body. The cause of non-lethal damage to Dickinsonia could not be established, but the local distribution of deformed specimens preserved in the same burial event alongside cyanobacterial colonies, and the presence of weak deformations, expressed only in shortening of the length of some isomers, lead to the conclusion that damage resulted from short episodes of physicochemical impact, rather than occasional attacks by a hypothetical macrophage.

Bituminous limestone of the Ediacaran Shibantan Member of the Dengying Formation (551–539 Ma) in the Yangtze Gorges area contains a rare carbonate-hosted Ediacara-type macrofossil assemblage. This assemblage is dominated by the tubular fossil Wutubus Chen et al., 2014 and discoidal fossils, e.g., HiemaloraFedonkin, 1982 and AspidellaBillings, 1872, but frondose organisms such as CharniaFord, 1958, RangeaGürich, 1929, and ArboreaGlaessner and Wade, 1966 are also present. Herein, we report four species of Arborea from the Shibantan assemblage, including the type species Arborea arborea (Glaessner in Glaessner and Daily, 1959) Glaessner and Wade, 1966, Arborea denticulata new species, and two unnamed species, Arborea sp. A and Arborea sp. B. Arborea arborea is the most abundant frond in the Shibantan assemblage. Arborea denticulata n. sp. resembles Arborea arborea in general morphology but differs in its fewer primary branches and lower length/width ratio of primary branches. Arborea sp. A and Arborea sp. B are fronds with a Hiemalora-type basal attachment. Sealing by microbial mats and authigenic cementation may have played an important role in the preservation of Arborea in the Shibantan assemblage. The Shibantan material of Arborea extends the stratigraphic, ecological, and taphonomic ranges of this genus.

A new species of microconchid tubeworm, Microconchus cravenensis is described from the Mississippian Cracoean reefs of North Yorkshire, United Kingdom. Despite the fact that some other microconchid species could have attained large tube length, the new species possesses the largest recorded diameter (to 7.7 mm) of the planispirally-coiled (attachment) tube and the largest recorded aperture diameter (8.3 mm) in the helically uncoiled portion. Thus, with respect to these features, Microconchus cravenensis n. sp. is the largest and most robust microconchid species recognized so far. At present, it is only known from the Craven Reef Belt of North Yorkshire, where it attached to corals and possibly bivalve shells, and was preyed upon by small durophagous animals, as indicated by repaired injuries preserved on one of the tubes.

A series of well-preserved specimens of the little-known Palaeogene species Biselenaria placentula (Reuss, 1867) warrant the designation of a new family of free-living cheilostome bryozoans, Biselenariidae n. fam. In contrast to the structural organization of all other free-living, lunulitiform cheilostomes, all zooids are enclosed almost completely by cuticular, exterior walls. Yet, like other lunulitiforms, the colony must be regarded as a highly integrated functional unit, as revealed through the unique, highly complex interior architecture. In creating the new monotypic family, the type species Biselenaria placentula is described in detail, while the ambiguous taxonomic status of the only other taxon, B. offaGregory, 1893, is discussed.

Assessment of unique and potentially significant fossils may be considerably compromised by surrounding matrix. This paper assesses a fossil barnacle group from the mid to late Eocene of Seymour Island, off the Antarctic Peninsula, that potentially has very significant phylogenetic importance. It discusses why the specimen could be significant, and describes and applies as a proof of concept an advanced imaging technique, using X-ray Computed Tomography (CT), that was effectively employed to confirm systematic taxonomy with virtual 3-D sections through the specimen. In this case, the Antarctic barnacle's complex internal plate morphologies were resolved by advanced 3-D imaging, such that a taxonomic attribution could be made to either the Archaeobalanidae or Austrobalanidae, excluding the initial assessment of Coronulidae, which would have otherwise been allusive.

The first fossil rove beetle (Coleoptera, Staphylinidae) from New Zealand is described from the earliest Miocene Foulden Maar fossil-Lagerstätte, Otago. The new species, Sphingoquedius meto n. sp., is attributable to the tribe Amblyopinini of the subfamily Staphylininae based on the scutellum with anterior scutellar ridge only; isodiametric microsculpture on the pronotum; multidirectional arranged setae on the elytra; and presence of radiating setae on the fourth abdominal tergite. Sphingoquedius meto n. sp. is the first Southern Hemisphere fossil record of Amblyopinini and its affinity to the extant fauna as well as biogeographic and paleocological implications are discussed.

Lovén's Law described the position of larger basicoronal ambulacral plates in echinoids. The smaller basicoronal plates form first in ontogeny. We restate Lovén's Law to describe the position of first ambulacral plates using Carpenter's ambulacra and left (L) or right (R) as: AR, BL, CR, DL, ER, with EA the pair of ambulacra both identical and adjacent. First ambulacral plates of the Cambrian edrioasteroid, Walcottidiscus, code identically. The transition from a tri-radiate 1-1-1 pattern to the 2-1-2 ambulacral pattern of Walcottidiscus and other pentaradiate Paleozoic echinoderms results in Lovén's Law. This provides an hypothesis for the origin of Lovén's Law and predicts its widespread occurrence among echinoderm classes.

The ‘BD different’ pattern of primary brachioles in pentaradiate glyptocystitoid Rhombifera results from subterminal branching of the ambulacra. The ontogenetic sequence was triradiate, then lateral ambulacra bifurcated, and finally second brachioles developed. Positions of second brachioles of pentaradiate glyptocystitoids code as AR, BL, CR, DL, ER. Other examples of Lovén's Law occur in Diploporita, Ophiuroidea, Edrioasteroidea, Edrioblastoidea, Holothuroidea, Ophiocistioidea, and Bothriocidaris. Our working hypothesis is that Lovén's Law arose with pentaradiality. An objective test requires a reliable independent landmark across all classes, which does not exist currently. Our hypothesis is only parsimonious if Lovén's Law arose just once in echinoderm evolution and is widespread within the phylum. So far, both conditions appear to be met, but edrioasteroid first ambulacral cover plates commonly exhibit an alternative Lovén-like pattern of AL, BL, CR, DL, ER, with AB the identical adjacent ambulacra.

The Brechin Lagerstätte of southern Ontario contains an exceptionally diverse and well-preserved Late Ordovician (Katian) crinoid fauna. We describe four genera and eight species of camerate crinoids from the Brechin Lagerstätte, including six new species. Consequently, the total diversity of the fauna now stands at 27 genera and 39 nominal species, thereby making it the most taxonomically diverse Ordovician crinoid fauna known. Taxa described include the diplobathrid Pararchaeocrinus kiddi new species and the monobathrids Glyptocrinus ramulosusBillings, 1856, Periglyptocrinus priscus (Billings, 1857a), Periglyptocrinus astricus new species, Periglyptocrinus kevinbretti new species, Periglyptocrinus mcdonaldi new species, Periglyptocrinus silvosus new species, and Abludoglyptocrinus steinheimerae new species. We summarize the taxonomic composition, diversity, and abundance distribution of all known crinoids from the Brechin Lagerstätte to better characterize the paleoecological structure and complexity of the community. We establish that the fauna is dominated by the subclass Pentacrinoidea, both in terms of abundance and species richness. In addition, we analyze species-level abundance data using Relative Abundance Distribution (RAD) models to evaluate the ecological complexity of the paleocommunity. We found that community structure of the Brechin Lagerstätte is best explained by an ecologically ‘complex’ RAD model, which suggests that species partitioned niches along multiple resource axes and/or the presence of multiple ecological ways of life. These results indicate that the Brechin Lagerstätte is significant not only for being the most taxonomically diverse Katian crinoid assemblage, but also for being an early ecologically complex fauna that developed in the wake of the Great Ordovician Biodiversification Event.

Family-level taxonomic concepts for Paleozoic Asteroidea are problematic; data availability for the family Urasterellidae, however, is judged sufficient for familial reappraisal. The survey cannot be fully comprehensive because certain available names are founded on very limited material, with specimens widely scattered among collections. Recognized urasterellid genera include UrasterellaSchuchert, 1914; AnthroosasteriasBlake, 2017; MeturasterBlake, Guensburg, and Lefebvre, 2016; SalterasterStürtz, 1893; StaurasteriasBlake, 2017; UlrichasterSpencer, 1950; and Pegoasterella pompom n. gen. n. sp. Other available generic names are held in abeyance. The name Urasterella has approached form-genus status, an outcome exacerbated by incomplete understanding of the type species. Urasterella huxleyi (Billings, 1865) is reassigned to Anthroosasterias. Relatively large specimen suites for Anthroosasterias huxleyi (Billings, 1865) and Salteraster grandis (Meek, 1872) enable some interpretation of urasterellid intrataxon variation, ontogenetic change, and life mode. Morphologic changes accompanying ontogeny of A. huxleyi are argued as favoring a shift from substrate surface feeding to feeding through extension of arms into the water column in a manner comparable to that seen among extant Forcipulatida and ophiurans.

The Rio Grande do Sul Coastal Plain (southern Brazil) is composed of extensive marine and continental deposits related to at least four lagoon-barrier systems of Pleistocene–Holocene age. Part of these deposits is currently submerged and passing through erosion processes by waves. Vertebrate and invertebrate body and trace fossils are constantly exhumed from these deposits and redeposited on the modern beach face. Among them, a total of 253 fragments of crustacean burrows were collected for this study. Two ichnospecies of OphiomorphaLundgren, 1891 were recognized (O. nodosaLundgren, 1891 and O. puerilisGibert et al., 2006), but most of the materials can only be assigned to the ‘SOT’ group (Spongeliomorphade Saporta, 1887, Ophiomorpha, and ThalassinoidesEhrenberg, 1944), mainly because of the lack of a pelleted lining. The absence of pellets and, as a consequence, the ichnotaxonomy of these specimens, is related to taphonomical processes (exhumation, reworking, and transportation) that acted during formation of the ex situ assemblage. The paleoenvironmental dynamics and a taphonomical model are presented to demonstrate how these processes affected the trace fossils since their construction, through exhumation until deposition. Neoichnological observations led us to infer larger producers in comparison to the extant ghost shrimp Sergio mirim (Rodrigues, 1971).

Brochuchus is a small crocodylid originally based on specimens from the early Miocene of Rusinga Island, Lake Victoria, Kenya. Here, we report occurrences of Brochuchus from several early and middle Miocene sites. Some are from the Lake Victoria region, and others are in the Lake Turkana Basin. Specimens from the middle Miocene Maboko locality form the basis of a new species, Brochuchus parvidens, which has comparatively smaller maxillary alveoli. Because of the smaller alveoli, the teeth appear to be more widely spaced in the new species. We also provide a revised diagnosis for Brochuchus and its type species, B. pigotti. A phylogenetic analysis supports a close relationship between Brochuchus and tube-snouted Euthecodon, but although relationships among crocodylids appear poorly resolved in the set of optimal trees, this is because Brochuchus and Euthecodon, along with early Miocene “Crocodylus” gariepensis from the early Miocene of Namibia, jointly adopt two distinct positions—either closely related to the living sharp-nosed crocodile (Mecistops) or to a group including the living dwarf crocodiles (Osteolaemus). Character support for a close relationship with Mecistops is problematic, and we suspect a closer relationship to Osteolaemus will be recovered with improved sampling, but the results here are ambiguous. In either case, Brochuchus is more closely related to living groups not currently found in East Africa. This material helps constrain the timing of crocodylian faunal turnover in the East African Rift Valley System, with endemic lineages largely being replaced by Crocodylus in the middle or late Miocene possibly in response to regional xerification and the replacement of continuous rainforest cover with open grasslands and savannas.

A large sample (>100 specimens) of the fossil rodent ThisbemysWood, 1959, from the early Eocene (late Bridgerian; Br3) Washakie Formation of Wyoming is described. Two species are recognized: a new species, T. intermedius n. sp., and Thisbemys cf. T. uintensis (Osborn, 1895). The large sample size of the former has allowed for a detailed study of variation in size and morphology within the species based on tooth-wear. As a result, some systematic changes in the species included in this genus are suggested: (1) T. brevicristaOstrander, 1986, is limited to the holotype, and all specimens previously referred to T. brevicrista are likely referable to T. plicatusWood, 1962; (2) statistical analysis supports the separation of T. plicatus from T. corrugatusWood, 1959, based on its smaller size and less-crenulated cheek teeth, which corroborates their existence at different horizons (T. plicatus earlier Bridgerian [Br2], T. corrugatus late Bridgerian [Br3]); (3) Paramys delicatiorLeidy, 1871, is suggested as the senior synonym of T. plicatusWood, 1962; (4) T. perditusWood, 1962, is limited to the early Eocene (Washatchian: Wa1-6); and (5) all specimens previously referred to T. niniWood, 1962, except the holotype, are referred to T. perditus (fide Korth, 1984; contra Anderson, 2015).

A new species of gopher, Gregorymys mixtecorum n. sp., is described from the Arikareean 1 (early Oligocene) of Oaxaca, southern Mexico. Phylogenetic analysis indicates that it is the sister species of G. veloxikua, which was also recently described from southern Mexico. Both species were collected from sediments of the Chilapa Formation that crop out in northwestern Oaxaca. Gregorymys mixtecorum n. sp. and G. veloxikua show differences in size and proportions that possibly reduced competition for resources, exploiting different microhabitats. Both Mexican species represent the oldest and the most southern records of Gregorymys in North America. The Mexican record of Gregorymys suggests that at least some entoptychine rodents diversified in southern Mexico or Central America, and that Geomyidae has had a wide geographic distribution in North America since the early Oligocene.

Treeshrews are small, Indomalayan mammals closely related to primates. Previously, three-dimensional geometric morphometric analyses were used to assess patterns of treeshrew lower second molar morphology, which showed that the positions of molar landmarks covary with intraordinal systematics. Another analysis used dental topographic metrics to test patterns of functional dental morphology and found that molar curvature, complexity, and relief were an effective means for examining patterns of variation in treeshrew dietary ecology. Here, we build on these analyses by adding two fossil taxa, Prodendrogale yunnanicaQiu, 1986 from the Miocene of China and Ptilocercus kylinLi and Ni, 2016 from the Oligocene of China. Our results show that Pr. yunnanica had a dental bauplan more like that of a tupaiid than that of a ptilocercid, but that the extant tupaiids, including Tupaia and Dendrogale, are more similar to one another in this regard than any are to Prodendrogale. This is contrary to our expectations as Prodendrogale is hypothesized to be most closely related to Dendrogale. Ptilocercus kylin, which has been proposed to be the sister taxon of Pt. lowiiGray, 1848, is characterized by dental morphology like that of Pt. lowii in crest and cuspal position but is interpreted to have been more frugivorous. It has been claimed that Ptilocercus has undergone little morphological change through time. Our results suggest that Pt. kylin was more ecologically distinct from Pt. lowii than previously proposed, providing a glimpse into a more complex evolutionary history of the group than had been inferred.

Materials from the localities of Araia d'Alcora in the Ribesalbes-Alcora Basin (Spain, early Miocene, Biozone C, MN4) have yielded an assemblage of erinaceids and metatherians, relatively rich for an Iberian site. The most common erinaceid is the gymnure Galerix symeonidisiDoukas, 1986, present in almost all of the studied sites. Other erinaceids in the faunal list are possibly an indeterminate species of the genera LantanotheriumFilhol, 1888 and AtelerixPomel, 1848, in what constitutes one of their oldest occurrences in Europe. Metatherians are represented by the herpetotheriid Amphiperatherium frequens erkertshofense (Koenigswald, 1970). The material described here was partially published by Furió and colleagues in 2012. We complete it with new material from the known localities and with material from new sites. We describe for the first time the lower dentition of this taxon in this basin, thus increasing knowledge of the high variability of its decidual molars. In addition, the climatic preferences of the species A. frequens (von Meyer, 1846), which was probably less strict in its humidity requirements than previously thought, are also discussed.