A diverse Wuchiapingian brachiopod fauna, which contains 57 species in 28 genera, is described from the Shuizhutang Formation at the Liannan section, Guangdong province, southeastern China. Four new species Tyloplecta liannanensis n. sp., Linoproductus huananensis n. sp., Araxathyris minor n. sp., and Permophricodothyris flata n. sp. are proposed. From well-preserved Liannan specimens, characteristics of the shell microstructures in Permianella are revised, and different morphologies of muscle scars in Permophricodothyris are distinctly shown. Until now, only several Wuchiapingian brachiopod faunas have been found in South China. Compared with these faunas, the Liannan fauna shows much higher α diversity and is more like faunas from southeastern China than those from the Yangtze area in faunal composition. The Liannan fauna is dominated with Neochonetes, Transennatia, Orthothetina, Permophricodothyris, and Cathaysia, which are normally larger and more strongly ornamented than their Changhsingian counterparts. The Wuchiapingian brachiopods in South China are represented mainly by the Douling fauna and Shuizhutang fauna. The Douling fauna has relatively low diversity and presents the survival stage after the Guadalupian–Lopingian boundary crisis. The Shuizhutang fauna has a much higher diversity and more key Changhsingian taxa and shows a rapid radiation stage. Faunal compositions of the two faunas indicate that the initial recovery of brachiopods occurred mainly at the genus level followed by a more rapid radiation at both genus and species levels.

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The horseshoe crab Limulus polyphemus (Linnaeus, 1758) is a famous species, renowned as a ‘living fossil’ (Owen, 1873; Barthel, 1974; Kin and Błażejowski, 2014) for its apparently little-changed morphology for many millions of years. The genus Limulus Müller, 1785 was used by Leach (1819, p. 536) as the basis of a new family Limulidae and synonymized it with Polyphemus Lamarck, 1801 (Lamarck's proposed but later unaccepted replacement for Limulus, as discussed by Van der Hoeven, 1838, p. 8) and Xyphotheca Gronovius, 1764 (later changed to Xiphosura Gronovius, 1764, another junior synonym of Limulus). He also included the valid modern genus Tachypleus Leach, 1819 in the family. The primary authority of Leach (1819) is widely recognized in the neontological literature (e.g., Dunlop et al., 2012; Smith et al., 2017). It is also the authority recognized in the World Register of Marine Species (WoRMS Editorial Board, 2021).

Eight bryozoan species are described from the Hanchiatien Formation (lower Silurian, Telychian) of southern Chongqing, South China. Four species are new: the trepostomes Asperopora sinensis n. sp., Trematopora jiebeiensis n. sp., and Trematopora tenuis n. sp., and the fenestrate Moorephylloporina parvula n. sp. One species, the cystoporate Hennigopora sp. indet., is described in open nomenclature. Moorephylloporina parvula n. sp. is eurytopic, occurring in all types of facies within the bioherms. Erect Moorephylloporina Bassler, 1952, Trematopora Hall, 1852, and Leioclema Ulrich, 1882 formed pioneering communities on weakly cemented substrata, whereas encrusting Fistulipora M‘Coy, 1849, Hennigopora Bassler, 1952, and Asperopora Owen, 1969 occurred on hardgrounds and formed densely compact framestones. Robust branched Trematopora and Leioclema tend to occur out of the reef core (framework) where they could have formed reef-flank thickets in more agitated conditions. The generic composition of the studied fauna correlates with other localities in South China, and they show general paleobiogeographic relations to Siberia and Indiana, USA.

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A new sinistrally coiled univalved mollusk Catalanispira n. gen. is described with two species; Catalanispira reinwaldti (Öpik, 1930) from the Middle Ordovician Kõgekallas Formation (Darriwilian) of Estonia and Catalanispira plattevillensis n. gen. n. sp. from the Upper Ordovician Platteville Formation (Sandbian) of northern Illinois, USA. Morphological features include a large, low-trochiform shell, a narrow lenticular aperture, a deep funnel-like umbilicus, a falcate inner lip and a large (1.4 mm wide) protoconch. Ornamentation consists of fine commarginal growth lines or ribs but superimposed on a slightly irregular shell surface. Catalanispira n. gen. is placed within the sinistrally coiled order Mimospirida and the family Onychochilidae, and Catalanispirinae n. subfam. is proposed. The large Lower Ordovician (Tremadocian) Pelecyogyra Ebbestad and Lefebvre, 2015 from Morocco and France is transferred to this new subfamily. The well-preserved initial growth stage of Catalanispira plattevillensis n. gen. n. sp. is cap-shaped, slightly asymmetrical, unusually large, and smooth, and represents either an unusually large embryonic shell (protoconch 1) or a larval shell (protoconch 2). It differs from the smaller protoconch described for the clisospirine Mimospira Koken in Koken and Perner, 1925, which might include a multiwhorled larval shell (protoconch 2). Mimospirids are dominantly Ordovician, and have been classified as untorted mollusks (only distantly related to gastropods), dextral hyperstrophic gastropods, or sinistral orthostrophic gastropods. Sinistral asymmetry already in the embryonic shell and lack of conclusive evidence for coiling direction, e.g., an operculum, could suggest that Catalanispira n. gen. or similar mimosprids were sinistral orthostrophic gastropods. Currently the group is therefore classified as a group of sinistral orthostrophic gastropods, unranked within the Gastropoda.

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Nemavermes mackeei Schram, 1973, found in the Mazon Creek fossil site and the Bear Gulch Limestone, was described initially as a free-living marine nematode. Here we investigate 13 specimens of N. mackeei from the Mazon Creek to reassess its morphology and identity, and also two specimens originally identified as Gilpichthys greenei Bardack and Richardson, 1977. Based on the extensive morphological variation among these specimens, N. mackeei encompasses multiple species that are only distantly related. The holotype of N. mackeei is a proboscis of Tullimonstrum gregarium Richardson, 1966, making N. mackeei a junior synonym of T. gregarium. However, the other specimens that we investigated could not be attributed to T. gregarium. We name a new species from these specimens: Squirmarius testai new genus new species, a cyclostome. One specimen is likely a juvenile G. greenei. Other specimens were not identified during this study but represent a variety of vermiform bilaterians.

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The new farreid hexactinellid sponge Hormathospongia dictyota new genus and new species, is described from the upper Santonian Dobbins Shale Member of the Forbes Formation of the Upper Cretaceous Great Valley Sequence from the west side of the Sacramento Valley, northwest of Sacramento. The relatively simple skeleton is composed of quadrangularly arranged hexactines with overlapping rays, an arrangement strikingly similar to the skeletal structure of early Paleozoic reticulosid hexactinellids. However, the California Cretaceous sponges clearly show those spicules embedded in siliceous beams that are united to form a solid dictyonal skeletal framework of only a single layer of regular mesh. Such an occurrence and stratigraphic relationships suggests that the dictyonine sponges had their origin from the simply spiculed reticulosid hexactinellids rather than from the more complex dictyosponges.

Lower Silurian conodonts were recovered from carbonate beds in the upper Zalaa and lower Sharchuluut formations at Yamaan Us in the Shine Jinst region, Gobi-Altai Zone, of southwestern Mongolia. Conodonts are described from the Zalaa Formation for the first time; key taxa recovered include Distomodus kentuckyensis Branson and Branson, 1947, Ozarkodina hassi (Pollock, Rexroad, and Nicoll, 1970), Pranognathus siluricus (Pollock, Rexroad, and Nicoll, 1970), and Pseudolonchodina expansa (Armstrong, 1990). These species constrain the onset of the Silurian carbonate platform, upper Zalaa to lower Sharchuluut formations, to the Pranognathus tenuis Zone, middle Aeronian. The presence of a cosmopolitan conodont fauna places these strata from the Gobi-Altai Zone in a basin-shelf marine setting with connection and circulation to the open ocean during the Llandovery.

The trilobite species Cryphaeus nicholsi Roy, 1929, was based on two pygidia from a Devonian red sandstone bed at Patacamaya, La Paz Department, Bolivia. Study of the syntypes (Field Museum of Natural History, Chicago) reveals that two well-known species are represented.

Recently, several dinosaur bones were rediscovered in the paleontological collections at the University of Tennessee, Knoxville, with a label indicating that the material was collected from the Cretaceous of west Tennessee. Since dinosaur remains have never been reported from Tennessee, this discovery prompted further investigation.

Tubular fossils, up to 2 mm in diameter and 60 mm in length, occur rarely in the upper Martinsburg Formation (Upper Ordovician), northeastern Tennessee Appalachians, U.S.A. The fossils are unbranched, straight or slightly bent, occasionally twisted and wrinkled, and not significantly tapered. Orientation of the fossils within shallow-marine tempestites suggests that they represent remains of organisms that were broken, transported, and deposited by storm waves and currents. The fossils are morphologically similar to many of the previously identified species belonging to the genus Sphenothallus, a relatively rare tube-dwelling Paleozoic marine invertebrate. Owing to the limited evidence for distal widening of the tubes, lack of holdfasts, and carbonaceous rather than phosphatic composition, the affinity of these fossils remains uncertain, and we refer to them as Sphenothallus-like.

Šnadjr (1980, p. 76) erected the proetid trilobite subgenus Coniproteus (Ryckholtia), with the type species Proetus ryckholti Barrande, 1846, from the Silurian (Ludlow, Kopanina Formation) of the Prague Basin, Czech Republic, perhaps better known to geologists as the Barrandian type area in Bohemia. Although originally designated as a subgenus (e.g., Chlupáč et al., 1980, p. 175; Chlupáč and Kukal, 1988, p. 114; Kříž et al., 1993, p. 819), Ryckholtia Šnadjr was subsequently elevated to generic rank (e.g., Sepkoski, 2002, p. 189, 519; Jell and Adrain, 2003, p. 441, 477; Edgecombe and Wright, 2004, p. 183).

An australian paleontologist would not be expected to be familiar with the genera of recent snakes in the Western Hemisphere. Thus, when A. A. Öpik erected the genus Lampropeltis to receive certain Middle Cambrian trilobites from the Mindyallan of Queensland (Öpik 1967, p. 182), he was appropriately unaware that the name had already been coined for a genus of smooth-scaled colubrids, the kingsnakes (Cope, 1860; Blanchard, 1921).

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.

New Devonian fossil material from Bolivia includes internal molds of two species of paleotaxodont bivalve, Palaeoneilo musculosa (Knod) and P. pondeana (Hartt and Rathbun), with numerous accessory muscle scars. The unusual pattern of these scars appears to have been derived from excessive splitting. These muscle scars are described and a tentative interpretation is made. An adaptative role cannot be determined with certainty and it appears that these patterns were short-lived novelties without later success.

Shells and opercula of bithyniid gastropods assigned to Gabbiella are found in high abundance in the Pleistocene upper Burgi and KBS Members of the Koobi Fora Formation, Turkana Basin, northern Kenya. The systematic paleontology of the Turkana Basin Gabbiella is revised herein based on morphological comparison with the opercula of other Recent African bithyniids. The fossils from the upper Burgi and KBS Members are here assigned to Gabbiella rosea Mandahl-Barth, 1968, a species not known from the Turkana fossil record before, but extant in this lake today. A sampling and taphonomic bias is identified which influences the relative abundance of Gabbiella shells and opercula, as a mesh size of 0.63 mm or less is necessary to capture all opercula preserved in the sediments. Accordingly, opercula were found to be significantly more abundant than shells, indicating a different preservation potential of shells and opercula, as the calcitic operculum is more robust than the aragonitic shell. In contrast to previous arguments that most shellbeds in the Turkana Basin sequence represent undisturbed life assemblages, a taphonomic bias is clearly evident reducing the fidelity of the Turkana Basin mollusk assemblages.

Although limpets are fairly common in shelly deposits, there are no reports of limpets preserved in the living position from the fossil record. The life style of capped-shaped limpet gastropods almost precludes preservation in a living position. Herbivorous alga-feeding limpets live attached to a firm surface. The surfaces of attachment vary widely from rocky surfaces, shells, or seaweed. Upon death the shells become detached and are incorporated in the nearby sediments or are transported to a site of final deposition.