New calcareous foraminifera are described from the uppermost Permian (Changhsingian; about 254–252 million years ago) carbonates of southern Turkey and their evolutionary schemes are discussed within the middle to late Permian time frame. Comprising Retroseptellina, Septoglobivalvulina, and Paraglobivalvulinoides, the Retroseptellininae new subfamily originated in the Wordian with thin and dense microgranular walls and became diverse and abundant in Changhsingian strata. Paraglobivalvulina? intermedia new species gave way to completely involute tests of Paraglobivalvulininae and survived into the Changhsingian. From the class Miliolata, Midiellidae new family is characterized by sigmoidal coiling and Pseudomidiella sahini new species is interpreted as the youngest Changhsingian descendant of this family. Glomomidiellopsis? okayi new species is interpreted as an evolutionary link between Capitanian Hemigordiopsis and Lopingian Glomomidiellopsis and survived into the Changhsingian. In Nodosariata, from the fully coiled Robuloides lineage of Robuloididae, two smaller species, R. lens and R. acutus, are each interpreted as ancestral to additional Changhsingian species. Robuloides lata new species and Plectorobuloides taurica new genus new species most likely originated from R. lens in the Changhsingian. The R. acutus lineage, characterized by the reduction of laterally thickened hyaline wall and the appearance of evolute coiling, yielded Robuloides? rettorii new species in the early Lopingian, and Pseudorobuloides reicheli new genus new species in the Changhsingian. Among the remaining new Changhsingian taxa, Calvezina anatolica new species and Eomarginulinella galinae new species belong to evolutionary lineages of weakly coiled Robuloididae, whereas Pseudocryptomorphina amplimuralis new genus new species requires further study to determine its precise taxonomic placement. From the family Pachyphloiidae, Robustopachyphloia farinacciae new species is a descendant belonging to one of the lineages of Pachyphloia in the Changhsingian. The presence of canal-like pores in the walls of some Pachyphloia specimens is suggestive of a new morphological structure in the evolutionary history of the Changhsingian foraminifera.

Several new foraminiferal taxa are described from the Changhsingian carbonates of southern Turkey, and their evolutionary relationships are discussed within the middle to late Permian time frame. Comprising Retroseptellina, Septoglobivalvulina, and Paraglobivalvulinoides, Retroseptellininae n. subfam. originated in the Wordian with thin and dense microgranular walls and became diverse and abundant in Changhsingian strata. Paraglobivalvulina? intermedia n. sp. appeared in the late Capitanian, survived into the Changhsingian, and gave way to completely involute tests of Paraglobivalvulininae. From the class Miliolata, Midiellidae n. fam., consisting of Midiella and Pseudomidiella, is characterized by sigmoidal coiling, and Pseudomidiella sahini n. sp. is probably the youngest known Changhsingian descendant. Glomomidiellopsis? okayi n. sp., which is interpreted as an evolutionary link between Capitanian Hemigordiopsis and Lopingian Glomomidiellopsis, survived into the Changhsingian. In the class Nodosariata, from the fully coiled Robuloides lineage of Robuloididae, Robuloides lata n. sp. and Plectorobuloides taurica n. gen. n. sp. most likely originated from R. lens in the Changhsingian. The R. acutus lineage, characterized by the reduction of laterally thickened hyaline wall and the appearance of evolute coiling, yielded Robuloides? rettorii n. sp. and Pseudorobuloides reicheli n. gen. n. sp. Calvezina anatolica n. sp. and Eomarginulinella galinae n. sp. are interpreted to have evolved from weakly coiled lineages in Robuloididae, whereas Pseudocryptomorphina amplimuralis n. gen. n. sp. is a poorly understood taxon and requires further study. Robustopachyphloia farinacciae n. sp. is interpreted as a descendant of some species within the genus Pachyphloia. The presence of canal-like pores in the wall of some Pachyphloia specimens is suggestive of a new morphological structure in the evolutionary history of the Changhsingian foraminifera.

Subadult shells of several Paleozoic brachiopod species were examined. Structures of the shells show that the species studied consumed plankton in the water column, which differs from modern brachiopods that subsist on nutrients from the yolk sac in their egg. One species from Baffin Island, Canada, had a particularly large subadult shell, indicating that it spent a long time in the water before settling. It may have needed this extra time to colonize the newly opened marine ecosystem on what is now Baffin Island after a period of sea level rise. The fact that fossil brachiopods developed differently than modern ones shows that one cannot always assume that the present is a good analogue for the past.

First-formed shells of several species of Dalmanellidae (Brachiopoda) from the Ordovician (Katian) of North America were measured and compared: Cincinnetina multisecta, Diceromyonia tersa, Diceromyonia storeya, Paucicrura corpulenta, Paucicrura rogata, and Paucicrura sillimani. Sizes and structures of the first-formed shells suggest that members of this family had planktotrophic subadults, with some species showing indications of only an unshelled larval stage and others showing both a larval stage and a shelled juvenile stage. This differs from modern rhynchonelliformean brachiopods, which all possess only a lecithotrophic larval stage. The range of sizes of first-formed shells of most studied species are similar, but P. sillimani of Baffin Island, Canada (middle Katian), has a significantly larger first-formed shell that formed during an extended juvenile stage. This may have enabled the species to colonize newly exploitable habitats during an interval of rapid sea level rise in Laurentia during the Katian. This plasticity of developmental modes in the Dalmanellidae shows not only that using distantly related modern brachiopods as an analog for extinct Paleozoic lineages may be misleading, but also that development can vary within a single lineage and that timing of developmental stages should not be considered a reliable character for use in phylogenetic studies of brachiopods.

Predators regularly attack their prey unsuccessfully, but the cause of failure is often difficult to determine in the fossil record. We report on drill holes in the shells of two Neogene bivalves from the Netherlands in which the drilling gastropod predators did not make effective use of their sensory capabilities to distinguish dead from live prey. These holes, which we call reverse drill holes, were produced from the inner side of the bivalve prey's shell. We propose that chemical cues from live prey directly around the dead shell stimulated the gastropods to make these mistakes. Hunger is another hypothesis for reverse drilling behavior. These holes are the earliest documented instances of reverse gastropod drill holes in the fossil record. In the two assemblages examined, reverse drill holes are rare, accounting for less than 1% of all drill holes, in contrast to other forms of unsuccessful predation, such as incomplete drill holes and multiply-drilled specimens. This finding suggests that the predator's sensory and decision-making processes were typically effective at differentiating between live and dead prey.

Predation is a behavior that is commonly unsuccessful, but the cause of failure is often difficult to determine in the fossil record. Here, we report on gastropod drill holes in two Plio- and Miocene bivalve specimens from the Netherlands created from the inner side of the bivalve prey's shell, which we call reverse drill holes. These holes are unequivocally caused by failure of the gastropod drilling predators to make effective use of their chemoreception and mechanoreception sensory adaptations. We hypothesize that the diffuse nature of chemical cues emanating from dense aggregations of living prey could have confused foraging predators and stimulated them to initiate the drilling process on empty valves. Poor decision making due to hunger is an alternative hypothesis. These traces represent the first reported examples of reverse gastropod drill holes from the fossil record, and the first attributed to Naticidae. Compared to other types of failed predation (incomplete drill holes and drill holes in multiply-drilled specimens) in the two assemblages studied, reverse drill holes are rare (< 1% of drill holes). This result implies that the driller's sensory and decision-making processes were generally reliable at distinguishing dead from live prey.

Fossil remains of extinct relatives of cephalopods are known to occur in Peruvian strata of Ordovician age (∼485–444 million years old) for a long time. However, they remain poorly known today. Here, we describe for the first time specimens that were collected from strata of the San José Formation of the Kimbiri and Inambari areas, southeastern Peru. The assemblage contains five species; one of them, Bactroceras cocafolium, is new to science. One other species is known from strata of the same age from elsewhere in the central Andes. The five species also show a relationship with cephalopod assemblages known from the old continents Gondwana and Avalonia.

The existence of Ordovician Peruvian cephalopods has been known since at least the 1910s. However, they have not been effectively documented previously with only a few described taxa listed in open nomenclature. Here, we describe a cephalopod assemblage at the finest taxonomic level possible. The specimens were collected from the Floian section (Baltograptus minutus graptolite Zone) of the San José Formation from the Kimbiri area, northwest of Cuzco (= Cusco), and from a section along the Inambari River, southeastern Peru. The dark mudstone-siltstone of the San José Formation was deposited within the Central Andean Basin. The assemblage contains five species of small orthoceracones belonging to four families and three orders, consisting of one indeterminate dissidocerid, one bathmoceratid (Saloceras sp.), one rioceratid (Rioceras? sp.), and two baltoceratids belonging to Annbactroceras grecicostatum (Kobayashi, 1937), and Bactroceras cocafolium new species. The dominance of small orthoceracones is typical for early Paleozoic pelagic cephalopod assemblages. One species, A. grecicostatum, is known from elsewhere in the Central Andean Basin. The other taxa indicate a peri-Gondwana-Avalonia paleogeographical relationship of the cephalopod fauna, which is consistent with previously published data from brachiopods and trilobites.

Kuamaia lata, an arthropod (jointed limbs and repeated body segments) from the Cambrian (approximately 518 million years ago) Chengjiang biota, China, belongs to a group of extinct arthropods that includes trilobites (i.e., Artiopoda). Computed tomography (CT) scans of new specimens of Kuamaia lata reveal a six-segmented head and predatory frontal appendages, the latter contrasting with sensory antennae considered to be a diagnostic character of Artiopoda. Evolutionary trees demonstrate that a predatory frontal appendage is ancestral for euarthropods but evolved secondarily in Kuamaia lata from an antenna within Artiopoda. The evolutionary position of Kuamaia lata adds support to a six-segmented head being ancestral for arthropods.

Phylogenetic analysis demonstrates that Kuamaia lata, a helmetiid euarthropod from the lower Cambrian (Series 2, Stage 3) Chengjiang Konservat-Lagerstätte, nests robustly within Artiopoda, the euarthropod clade including trilobitomorphs. Microtomography of new specimens of K. lata reveals details of morphology, notably a six-segmented head and raptorial frontal appendages, the latter contrasting with filiform antennae considered to be a diagnostic character of Artiopoda. Phylogenetic analyses demonstrate that a raptorial frontal appendage is a symplesiomorphy for upper stem-group euarthropods, retained across a swathe of tree space, but evolved secondarily in K. lata from an antenna within Artiopoda. The phylogenetic position of K. lata adds support to a six-segmented head being an ancestral state for upper stem- and crown-group euarthropods.

A new genus and species of dalmanitid trilobite, Waukeshaaspis eatonae, is here described based on ∼200 exoskeletons that were recovered from bedding plane clusters that were part of the Silurian soft-bodied Waukesha Biota. This form has a notable embayment in the posterior margin of the posterior trunk tergite (pygidium) where a long spine is commonly found in this form's close relatives. This structure might have enhanced respiration while the animal was in an enrolled posture.

A new dalmanitid trilobite is described from the early Silurian (Telychian) Waukesha Biota in Wisconsin, USA, best known for its variety of exceptionally preserved arthropods. Waukeshaaspis eatonae new genus new species is the most common trilobite found in the Waukesha Biota, numbering ∼200 specimens, allowing a thorough description of the dorsal exoskeleton. This new taxon has a combination of characters unique to the Dalmanitidae, including a distinct embayment on the posterior margin of the pygidium. Embayments are rare for dalmanitids, most species having instead a caudal spine. The lengthening of the genal spines might have served a similar function to that which a caudal spine would have served, allowing the embayment to fulfill a different function, related to keeping an opening when enrolled. The abundance at the preservation site suggests physiological tolerance at the habitation site.

Sexual dimorphism in surface sculpture as a result of sexual conflict in mating systems is well known in many extant diving beetles but was never recorded from fossils. We record two species of diving beetles from early Miocene Mexican amber and assign them to the hyperdiverse extant genus Copelatus. One of them, Copelatus chiapas new species, represents the first fossil diving beetle with documented sexual dimorphism in sculpture on elytra. We hypothesize that those species lived in freshwater habitats, such as swamps or pools/puddles, in a Tertiary rain forest about 20 million years ago.

Two diving beetle species (Coleoptera, Dytiscidae) from the extant genus Copelatus Erichson are documented from early Miocene Mexican amber. Copelatus chiapas new species is described based on a series of specimens of both sexes. Copelatus chiapas n. sp. is the third species of the subfamily Copelatinae described from amber and the first fossil diving beetle for which distinct sexual dimorphism is documented. The other species remains identified to genus level only, due to poor structural visibility. Key morphological characters of the species are illustrated.

An interdisciplinary study of the Upper Carboniferous vertebrate fossil locality known as the Danville Bonebed combines geological, paleontological, and historical research that clarifies the depositional setting, collecting history, and fate of a site first reported in 1875 by renowned paleontologist E.D. Cope. Located in Vermilion County, on the eastern edge of central Illinois, the deposit was discovered on Horseshoe Bend, a modern cutbank of the Salt Fork of the Wabash River and, after some 30 years of collecting, was obliterated by slumping and erosion. Yet, specimens from the locality are critical because they predate the discovery of comparable material from the Lower Permian of Texas. The Horseshoe Bend assemblage includes freshwater to amphibious forms and is dominated by the early synapsid Clepsydrops.

One of the earliest discoveries of Permo-Carboniferous terrestrial vertebrates in North America occurred in 1875 along Horseshoe Bend, a cutbank on the Salt Fork of the Vermilion River west of Danville, Vermilion County, east-central Illinois. The discovery was soon eclipsed by the description of similar but much more complete remains from the Lower Permian of Texas in 1878. The deposit itself was obliterated by slumping and erosion in the earliest 1900s and has not been collected since despite repeated efforts. Previously unreported outcrop records and subsurface data indicate that the deposit originated as a paleochannel fill in the Inglefield Sandstone Member of the Patoka Formation, which underlies the Macoupin Limestone Member (early Missourian Stage of the Midcontinent, early Kasimovian Stage of global Carboniferous time scale). In addition to aquatic to terrestrial tetrapods, teeth of lungfishes (Sagenodus Owen, 1867, Conchopoma Cope, 1877a, Gnathorhiza Cope, 1883a) and teeth, occipital spines, and coprolites of a xenacanth shark (Orthacanthus Agassiz, 1838) are known from Horseshoe Bend. The teeth of the marine petalodont shark Janassa Münster, 1839, also are present in the collection but presumed to have been derived from one of the beds on the cutbank that produced brackish to marine invertebrate fossils. Alhough not diverse, the tetrapod assemblage is significant in that it contains the oldest diplocaulid amphibian (Diplocaulus salamandroides Cope, 1877a), fragmentary remains of the oldest diadectid and limnoscelid stem reptiles, and possibly the oldest captorhinid eureptile, all of which have not been adequately described. The ophiacodontid synapsid Clepsydrops Cope, 1875, is the most common fossil at Danville, which could be an artifact of primitive collecting methods that did not promote the recovery of articulated material. An accurate stratigraphic placement of the Horseshoe Bend deposit and a review of other late Carboniferous tetrapod localities reveals that this important Illinois locality combines an overlooked vanguard of terrestrial taxa regarded as Permo-Carboniferous (Kasimovian-Asselian) and amphibious to aquatic forms known from older, Moscovian deposits.

Understanding food chains in ancient ecosystems is one of the goals of paleoecology. Direct evidence for these interactions is rare and includes fossils with stomach contents and bite/tooth marks. We document a rare occurrence of a bite mark to the neck vertebra of a juvenile fossil specimen of a giant pterosaur from the Cretaceous of Alberta, Canada, 76 million years ago. Based on the size and shape of the tooth mark, and comparison with modern animals, we suggest that a crocodylian bit the pterosaur, but we were unable to determine whether this was active predation or scavenging. Feeding traces on giant pterosaurs are rare, so this provides novel details on how they fit into this ancient ecosystem.

Identifying feeding interactions in the fossil record remains a key challenge for paleoecologists. We report the rare occurrence of a conical, perforative bite mark in a cervical vertebra of an azhdarchid pterosaur, which we identified as a juvenile individual of Cryodrakon boreas Hone, Habib, and Therrien, 2019 from the Campanian Dinosaur Park Formation in Alberta, Canada. Based on comparative analysis of the dentition and ecomorphology of potential trace makers in the Dinosaur Park Formation, as well as the morphology of the trace, the most likely candidate is a crocodilian, although whether it was made as a result of scavenging or predatory behavior is unknown. Feeding interactions involving pterosaurs are rare globally, whereas crocodilian bite marks are not uncommon in Cretaceous terrestrial ecosystems. Given the opportunistic feeding style and known range of food items for both extant and extinct crocodilians, pterosaurs can be counted as a rare, but not surprising, component of at least some Cretaceous crocodilian diets.

Trace fossils attributed to waterbird foraging are identified from mudflat successions in the Eocene of Utah. These traces occur in close association with the footprint taxon Presbyornithiformipes feduccii, which purportedly was emplaced by the extinct waterbird Presbyornis pervetus. Four distinct morphologies of foraging traces are identified, which are assigned to four new trace fossil taxa: Erevnoichnus blochi, E. strimmena, Ravdosichnus guntheri, and Aptosichnus diatarachi. These trace fossils are interpreted to record tactile (non-visual) foraging strategies by lake-margin waterbirds searching for prey.

Foraging traces associated with the web-footed avian footprint ichnotaxon Presbyornithiformipes feduccii are described. Four new ichnospecies in three new ichnogenera are established to identify and describe the traces that resulted from foraging behaviors. All four ichnotaxa are, in places, overprinted by P. feduccii footprints and occur either laterally to, or sinuously woven between, P. feduccii trackways and therefore were clearly emplaced by the P. feduccii tracemaker.

Erevnoichnus blochi new ichnogenus new ichnospecies is established for a series of pits, joined by a marginal groove, that are associated with web-footed bird trackways. This ichnotaxon is interpreted to record regular probing/gaping as a waterbird swept its head from side to side searching for food. Erevnoichnus strimmena n. igen. new ichnospecies is established for en-echelon, gently arcuate grooves produced through forward probing by a waterbird searching for food. Ravdosichnus guntheri new ichnogenus new ichnospecies is established for simple grooves with u-shaped profiles produced when a waterbird dragged its bill backwards through the sediment. Aptosichnus diatarachi new ichnogenus new ichnospecies is established for a broad, shallow groove/trough characterized by sinuous margins and a complex, irregular fill. It is interpreted to record thorough bill stirring in an area with common prey.

All four ichnotaxa named herein are interpreted to record tactile feeding behavior by a marginal lacustrine waterbird searching for prey. Their association with Presbyornithiformipes feduccii suggests that the purported tracemaker, Presbyornis pervetus, did not forage solely through filter-feeding but was also capable of tactile foraging for larger prey.

Soricidae (true shrews) is the largest modern family of insectivores. Already by the Late Miocene (from ca. 11.5 to ca. 5.5 million years), soricid faunas displayed a tendency to diversify. This is confirmed by the study of eight species of Soricidae from the Late Miocene of Slovakia, including one new genus. Additionally, we described one species of the extinct family Plesiosoricidae. Because of the increasing diversity of true shrews and the early record of several species, faunas from Slovakia confirm the key role of central Europe in the growth of this family during the Late Miocene. Furthermore, the large Slovak collections allowed us to gather new taxonomic information on previously reported species of Plesiosoricidae (Plesiosorex evolutus) and Soricidae (Paenelimnoecus repenningi, Paenesorex bicuspis, Crusafontina endemica, Crusafontina kormosi, Amblycoptus jessiae, Asoriculus gibberodon, Petenyia dubia), as well as on our newly named Soricidae, Isterlestes aenigmaticus n. gen. n. sp.

Soricidae is the most species-rich eulipotyphlan family since the Pliocene. Numerous Late Miocene soricids and plesiosoricids are well known from southern Europe. Localities from central Europe, despite being rare, historically have yielded better preserved material that reveals a great diversity. We here add to this existing record with the description of eight species from MN9- to MN12-aged localities of Slovakia (Paenelimnoecus repenningi, Paenesorex bicuspis, Isterlestes aenigmaticus n. gen. n. sp., Crusafontina endemica, Crusafontina kormosi, Amblycoptus jessiae, Asoriculus gibberodon, Petenyia dubia), alongside one species of Plesiosoricidae (Plesiosorex evolutus). The early occurrence of A. gibberodon and A. jessiae, the occurrence of Paenesorex, and the identification of Isterlestes aenigmaticus n. gen. n. sp., reinforce the hypothesis that the Pannonian region (south-eastern central Europe) was a source area for several soricid taxa (Allosoricinae, Anourosoricini, Soricini) during the Late Miocene.