We examine the effects of mean annual temperature (MAT) and coldest month mean temperature (CMMT) on Eocene and modern distributions of the cockroach genus Diploptera de Saussure, 1864. Today, Diploptera range in parts of the Sino–Japanese, Oriental, and Oceanian Realms with upper mesothermal to megathermal MAT and mild CMMT. In the Eocene greenhouse world, Diploptera ranged from microthermal to megathermal climates, with two published species in Wyoming, USA, four new species that we name (Diploptera reticulata, Diploptera rothi, Diploptera simeoptera, and Diploptera praecisus), and eight incertae sedis specimens from Messel, Germany; British Columbia, Canada; and Washington, USA. All of these localities had mild winters with few if any frost days, and so the ranges of modern and Eocene Diploptera are constrained by CMMT, not MAT. This is consistent with a tropical/temperate mix of fossil taxa in microthermal Eocene plant and insect communities being explained by mild CMMT. It does not, however, explain why taxa that today inhabit temperate climates mixed with tropical taxa in Eocene upper mesothermal to megathermal climates. This might be due to their cold tolerance evolving after the Eocene with the onset of cold extra-tropical winters, only then establishing their modern temperate association. Therefore, thinking of them as tropical or temperate organisms in the greenhouse Eocene is not appropriate. To survive in post-Eocene extra-tropical latitudes, animals and plants either adapted to colder winters, went extinct, were restricted to reduced extra-tropical mild winter refugia, or, like Diploptera, retreated to the tropics.

UUID: http://zoobank.org/3cfa2688-6001-4499-8a48-a83de9f6bb26

In times when science, including paleontology, is being questioned by some, the rising interest in the paleontology and paleobiology of the most intelligent invertebrates, namely cephalopods, may raise the hope for a brighter future. Here we provide an overview of some exciting fields in cephalopod research, where (in our biased opinion) the most impressive advances have been made. These are, in roughly stratigraphical order: the phylogeny of early cephalopods (using Bayesian approaches); the origin of ammonoids; functional morphology of ammonoids (using ammonoid robots, grinding tomography, finite element analyses); stable isotope geochemistry of Mesozoic–Cenozoic cephalopods; ammonoid reproduction (based on exceptionally preserved fossils and substantive fecundity estimates); ammonoid morphological evolution and biodiversity dynamics; early coleoid evolution (multispectral imaging, RTI); new coleoid systematics; coleoid anatomy (synchrotron, UV); coleoid diversity in the Cretaceous (“digital fossil mining,” i.e., a system that excavates all fossils embedded in rocks through a combination of automated grinding tomography and artificial intelligence); food-web positions of various cephalopods (as prey or predator); and nautiloid evolution. Furthermore, we highlight some fields that require research focus and discuss threats and problems impacting research on fossil cephalopods.

The Mascall Formation of eastern Oregon preserves a rich fossil flora, offering crucial insight into Miocene vegetation and climate in the Pacific Northwest (PNW). However, a continuous age-depth model for the formation is lacking, limiting correlation with regional tectonic and global climate trends. Additionally, it is unclear whether the humid forests previously inferred from the Mascall flora reflect widespread regional vegetation or localized lakeside habitats, leaving the timing of forest-to-open habitat transitions in the PNW unresolved.

To address these gaps, we present new U-Pb geochronology and Bayesian age-depth modeling, paired with a multiproxy analysis of plant macrofossils, phytoliths, and palynomorphs, and a review of taphonomic literature, to reconstruct regional vegetation and climate. A dated ignimbrite at White Hills (16.131 ± 0.011 Ma) helps constrain the base of the formation, and age modeling enables precise correlation with Miocene global climate events. Fossil evidence indicates deciduous angiosperm-dominated closed-canopy forests under warm temperate, humid conditions with minimal summer drought. Phytoliths additionally reveal that thermophilic palms and gingers and grassy patches existed in the overall forested landscape. These results contrast with more open contemporaneous habitats in the Great Plains and Rocky Mountains and suggest a unidirectional open habitat transition in the PNW was delayed, occurring after deposition of the Mascall flora. The persistence of a humid-adapted flora east of the Cascades also implies the range had not yet reached elevations sufficient to generate a prominent rain shadow. This study demonstrates the value of multiproxy approaches in resolving Miocene climate and vegetation structure in the PNW.

Protopalpares lindgrenae new genus new species (Neuroptera: Myrmeleontidae) is described from the Fossil Butte Member of the early Eocene Green River Formation (Wyoming, USA). This is the first Neuroptera species from the Fossil Butte Member, and the first fossil Palparinae. It is assigned to this subfamily based on the synapomorphy proposed here that the forewing posterior branch of RP1 and the stem of MP+CuA1 curve toward each other and are connected by two aligned crossveins at their closest. The venation of Protopalpares is most similar within the family to that of the Early Cretaceous Palaeonleontidae, indicating that Palparinae and Palaeonleontidae are likely closely related.

UUID: http://zoobank.org/fc4c124c-eb4b-432e-833c-cde7e595f653

Aplodontiid rodents are a diverse group of Oligo-Miocene rodents in North America that declined dramatically in the late Miocene leading to their current depauperate diversity of a single living species. The late Oligocene is a period of particularly high diversity for the group, especially in the northwestern quadrant of North America, including the Northern Great Plains, Northern Rockies, and Pacific Northwest regions. One of the more poorly-known genera in this time period is Rudiomys Rensberger, 1983, described from a single specimen that he designated the type of Rudiomys mcgrewi Rensberger, 1983, a fossil collected in the otherwise abundant vertebrate assemblages of the John Day Formation. Since that first publication, additional material of the genus has come to light, both in the type area in Oregon and in similarly aged deposits of western Montana’s Cabbage Patch beds. The new material from Oregon provides a more complete understanding of the dental morphology of the genotypic species. The Montana occurrences yield two additional species of the genus, Rudiomys drummondensis new species and Rudiomys intsook new species, which bear out some tentative ecological inferences from Rensberger’s original description, showing that Rudiomys is very likely a habitat specialist. This ecology explains its geographically limited distribution relative to other meniscomyine genera. The low-crowned dentition and bunodont morphology in this unusual aplodontiid could indicate a greater affinity for more closed habitats. This study not only yields a more complete understanding of the dental morphology of Rudiomys but also reveals the even greater diversity of late Oligocene aplodontiid species.

UUID: http://zoobank.org/681f9549-ab2f-4ac1-ba87-9467a7609b34

Oreodonts (superfamily Merycoidodontoidea) existed in the John Day region of Oregon from the Eocene through the Miocene, with considerable changes in their diversity over time. We present a variation-informed taxonomic revision of local oreodont species that preserves two species of Agriochoeridae, Diplobunops kardoula Emery, Davis, and Hopkins, 2016 and Agriochoerus guyotianus Cope, 1878a, and seven species of Merycoidodontidae, Eporeodon occidentalis Marsh, 1875, Hypsiops brachymelis Douglass, 1907, Merycochoerus magnus Loomis, 1924, Oreodontoides oregonensis Thorpe, 1921b, Paroreodon marshi Thorpe, 1921b, Promerycochoerus superbus Leidy, 1870, and Ticholeptus zygomaticus Cope, 1878b. We then applied this updated taxonomic revision to the stratigraphically controlled specimens at the John Day Fossil Beds National Monument to provide a detailed biostratigraphic revision. We found the Picture Gorge ignimbrite marked a major change in oreodont ecological role coinciding with changing environment. The arboreal, clawed Agriochoerus was extirpated at the Picture Gorge ignimbrite, and the large terrestrial Promerycochoerus arrived. Eporeodon remained but decreased in size. A maximum of five oreodont species were recorded at any one time, peaking in diversity in the Kimberly Member (25.486–26.597 Ma).

Ground squirrels (Rodentia, Sciuridae, Xerinae, Marmotini) diversified on the central Great Plains of North America during the Pliocene and Early Pleistocene, likely associated with the emplacement of modern-type grasslands. This diversity of Pliocene–Early Pleistocene ground squirrels is well documented from southwestern Kansas but is not well understood farther north and east on the Great Plains, a region that was periodically glaciated during the Early Pleistocene. Here, I report a composite assemblage of at least 10 species of ground squirrels from three Early Pleistocene (late Blancan) faunas in northeastern Nebraska, with eight species co-occurring at Big Springs. These fossils document early regional occurrence of the crown clade within Marmota Blumenbach; late regional persistence of the giant ground squirrel, Paenemarmota barbouri (Hibbard and Schultz); the earliest record of Poliocitellus Howell; the earliest record of Urocitellus Obolenskij from the Great Plains; early appearance of a small prairie dog–like ground squirrel, likely ?Cynomys andersoni Goodwin, otherwise only known from the early to middle Pleistocene of Colorado; and the presence of a distinctive ground squirrel described herein as Nebraskocitellus voorhiesi new genus new species. Overall, these findings document high regional diversity of ground squirrels during the Early Pleistocene, indicate the transitional composition of Early Pleistocene assemblages, and suggest that “modernization” of the ground squirrel assemblage on the central Great Plains began earlier in the northeast than documented in southwestern Kansas.

UUID: http://zoobank.org/8e35d11a-9ea6-4269-96e3-2be783de48a9

Reflecting the long-term decline in the generic diversity of order Conulariida Miller and Gurley, 1896 following its peak during Mid–Late Ordovician times (Leme et al., 2008, fig. 1; Bernad et al., 2026, figs. 1, 2), the global fossil record of conulariid cnidarians in the Mississippian System is dominated by the genus Paraconularia Sinclair, 1940 (Fig. 1; Table 1). Thus, most Mississippian conulariid faunas consist of one or two species in Paraconularia plus, in some cases, Conularia Miller in Sowerby, 1821 or, possibly, Holoconularia Hergarten, 1985. The cosmopolitan distribution of these conulariids was facilitated by the Devonian–Carboniferous, Austropanthalassic-Rheic migration corridor (e.g., Torres-Martínez and Sour-Tovar, 2023), the westernmost portion of which directly connected Gondwana to Laurentia (Fig. 1).

The Middle Ordovician Oil Creek Formation in the Arbuckle Mountains of southern Oklahoma has been well known for its echinoderm-rich limestones for decades. Despite the abundance of separate plates that accumulated in shallow-water, storm-swept environments, complete specimens are rare. Consequently, no new echinoderm taxa were described from the formation prior to the work of the authors. Construction of Interstate Highway 35 in the late 1960s provided rare access to relatively fresh exposures in the 1970s when many of the specimens described herein were collected. The site now is largely overgrown.

Crinoids described in this paper include (1) the hybocrinid Guensburgocrinus lineatus n. gen. n. sp., which is apparently intermediate between Syndiasmocrinus Guensburg and Sprinkle, 2022 (Early Ordovician) and Hybocrinus Billings, 1857 (Late Ordovician); (2) ?Hybocrinus nanobrachiatus n. sp.; (3) three species of the cladid ?Palaeocrinus Billings, 1859; (4) two species of the cladid ??Carabocrinus Billings, 1857, both lacking radial-oral plate slits; and (5) the camerate Reteocrinus oklahomensis n. sp., the oldest known species in the genus. Additional crinoid diversity is indicated by unassigned separate calyx plates. Crinoids appear associated with several species of blastozoans including parablastoids, rhombiferans, diploporitans, and paracrinoids.

UUID: http://zoobank.org/eb6434b1-05dd-4c7a-8007-a62680C66860

The rhynchonellide brachiopod Altaethyrella Severgina, 1978 is a key component of the shallow-water Altaethyrella brachiopod fauna that flourished in the tropical Proto-Tethys during the Katian (Late Ordovician). This study describes an unusually small species of the genus, Altaethyrella xuejiaoi new species, from the lower Katian (Ka-1) Yingan Formation in northwestern Tarim, Xinjiang, Northwest China. With an average length of 8.60 mm, width of 9.73 mm, and depth of 5.69 mm, it is approximately two-fifths the size of typical Altaethyrella species, although the presence of a central myophragm in the dorsal cavity and well-developed teeth confirms that the specimens of the new species are mature and not simply juvenile forms. This species inhabited the shallow-water reef-stromatoporoid bioherm, providing new insights into the origination and early evolution of the rhynchonellides. Furthermore, this study contributes new generic occurrence data that will improve our understanding of the paleogeographic distribution of the Altaethyrella fauna prior to the Late Ordovician Mass Extinction (LOME).

UUID: http://zoobank.org/f3f5959a-7d6d-4554-914c-585658e3eca8

Ecological live–live interactions in fossil invertebrates, although providing valuable information about the past environment and ecology, are still underexplored. Trematode parasites have a complex life cycle, often utilizing mollusks as their intermediate hosts. However, since the trematodes themselves lack a rigid skeleton, these interactions can be detected only when there is anomalous growth in the shell, the sole preserved part of the mollusk. When malformations produced by the host are preserved, it may be concluded that the mollusk was alive at the time of interaction. This study aims to assess the evidence of different ecological interactions preserved in the shells of Zidona dufresnii (Donovan, 1823) and determine which were results of a life-to-life relationship, as well as which organisms were involved in that interaction. A total of 894 shells collected from Quaternary deposits in southern Brazil were analyzed regarding the presence and morphology of bioerosions and malformations. As a result, 10 ichnogenera of bioerosion traces were identified. In addition, seven types of malformations were observed. These include pits and igloo-like structures, which are results of infestation by parasitic trematodes. Blister and sheet forms indicate response to the presence of spionid species that perforated the shell. Verrucose malformations, we suggest here, are also indicative of trematode infestation. ¹⁴C dating shows that the gastropod shells are derived from both Holocene and Late Pleistocene deposits, indicating significant time averaging. While evidence of life–life interaction is more common in Holocene shells, Pleistocene shells display a greater prevalence of bioerosion traces.

The “butter shale” Lagerstätten of the Cincinnati Arch region is renowned for its well-preserved fossil records, documenting the dynamics of the Late Ordovician “Richmondian Invasion,” during which faunal migration from multiple source basins into the region led to a drastic increase in diversity. Among the diverse fossil groups, ostracods, an important component in marine benthic communities, have been substantially neglected, despite their great potential for paleobiogeographical, paleoecological, and macroevolutionary reconstructions. Here we systematically document ostracods from the butter shale for the first time, with 29 species of 24 genera being described. Two new species, Milleratia binodosa n. sp. and Daleiella? cincinnatiensis n. sp., are examined in detail. Analyses on faunal composition indicate that ostracods also participated in the process of the invasion during the early and main stages, as evidenced by the presence of both native and migrated taxa from other paleobasins in Laurentia. The studied ostracod fauna, characterized by the dominance of the suborder Binodicopina with relatively low diversity but high abundance, is associated with siliciclastic depositional environments and is consistent with the interpreted depositional setting of the butter shales. We also found strong biogeographical connections of the butter shale ostracod fauna with those within Laurentia as well as with faunas from adjacent paleocontinents, especially Baltica and Avalonia.

UUID: http://zoobank.org/1718afb4-a453-4b6a-b5d8-3c36dad835fd

The genus Aporia is a group of butterflies distributed throughout the Palearctic region. A fossil forewing from the caldera lake deposits of the Teragi Group (ca. 2.8–2.2 Ma: Late Pliocene–Early Pleistocene) is described and assigned to the extant species Aporia potanini Alphéraky. The fossil provides direct evidence that Aporia potanini was historically distributed in Japan, at the eastern margin of the Palearctic, and that the species was present at least by the Late Pliocene. This represents the oldest known fossil record of extant butterfly species.

The Ediacaran–Cambrian boundary, representing one of Earth’s most critical transitions, is currently defined by the Fortune Head (Newfoundland, Canada) GSSP (Global Standard Stratotype Section and Point) at a point once regarded as the first appearance of the branching trace fossil Treptichnus pedum. However, T. pedum has subsequently been found below the GSSP, and its global distribution is primarily restricted to siliciclastic facies where application of alternative biostratigraphic and chemostratigraphic correlation tools is challenging. Investigations of acanthomorphic acritarchs in basal Cambrian strata of South China suggest that these microfossils could provide a robust complementary biostratigraphic marker for the Ediacaran–Cambrian boundary. Acanthomorphic acritarchs are widely distributed across the Yangtze Platform in chert–phosphorite layers intercalated with carbonates and shales, thereby allowing their biostratigraphic occurrences to be calibrated with small shelly fossil biozones and carbon isotope data.

Here, the earliest Cambrian Asteridium–Heliosphaeridium–Comasphaeridium (AHC) assemblage biozone is identified at 11 localities within the Yanjiahe, lower Niutitang, and upper Liuchapo formations, representing diverse depositional environments. Two latest Ediacaran microfossils, both characterized by uniserially chained modules and representing a characteristic Ediacaran assemblage (the Horodyskia minor–Nenoxites jiumenensis, or HmNj, assemblage biozone), are also identified in the Liuchapo Formation, but do not overlap with the Cambrian AHC acritarch biozone. The AHC assemblage biozone is demonstrated to be stratigraphically equivalent to basal Cambrian small shelly fossils and a negative δ13C isotope excursion known to occur at the Ediacaran–Cambrian boundary. Thus, in South China, the AHC and HmNj assemblage biozones can be used to effectively and reliably constrain the Ediacaran–Cambrian boundary.

UUID: http://zoobank.org/2fd52705-f7ef-4276-897e-10e89efb04ad

Nogodinidae is a moderately small and cosmopolitan family of planthoppers with most species inhabiting tropical zones. Under Nogodinini, the subtribe Nogodinina comprises 14 species (11 extant and three fossils) with primary distribution to the New World humid forests. Herein, a new planthopper genus and three new species, Pauchus loisae Iscavel and Pinedo-Escatel, P. tsakal Iscavel and Pinedo-Escatel, and P. nensak Iscavel and Pinedo-Escatel from Mexican Early Miocene amber are described, imaged, and illustrated. Pauchus n. gen. can be distinguished from other fossil and extant Nogodinina genera by the following combination of characters: (1) subparallel markings in the frons that converge towards the clypeus, (2) tegmina with reduced ScP+R(+MA) vein shorter than any living or extinct taxa, (3) a transverse vein from MP to CuA splitting the median cell, and (4) five lateral spines on hind tibia. Dichotomous keys to all species of the new Nogodinid genus and to distinguish it from other New World Nogodinini genera are provided. Morphological similarities exhibited by the new taxa to other members of the tribe are also discussed.

UUID: http://zoobank.org/6a9d51de-4cb8-4099-84d0-bd2f77089adb

Conodonts with conical elements that closely resemble Paleozoic species reappeared in the Early Triassic. The phylogeny, evolution, and paleoecology of these conodonts are poorly known. In this study, we describe a new species of Neostrachanognathus, N. koikei n. sp., one of the conical conodonts, and reconstruct the conodont apparatus of this species according to natural assemblages from the “Toishi-type” siliceous claystone of Japan. The apparatus of N. koikei consists of 15 elements, including two pairs of P, one pair of M, and four pairs of S elements, and a single S0 element. Notable features include conical P1 and P2 elements and nine S elements that are similar in morphology to each other. The S elements of N. koikei are identified as belonging to the form species “Neohindeodella aequiramosa” Kozur and Mostler, 1970, specifically to the morphology occurring from the Spathian to the Anisian. Furthermore, S elements of the type species of Neostrachanognathus, N. tahoensis Koike, 1998, appear to correspond to “Neohindeodella benderi” (Kozur and Mostler, 1970). Therefore, from these S-element morphologies, we conclude that Neostrachanognathus belongs to the family Ellisoniidae. These conodonts with simplified elements flourished and were widely distributed throughout the world, from continental shelves to the open ocean, during the Early Triassic to the early Middle Triassic.

UUID: http://zoobank.org/5e21971a-aac9-432c-8413-1994293867ab

Thylacocephalans are a peculiar group of fossil pancrustaceans characterized by a shield enveloping most of the body, large compound eyes, three pairs of raptorial appendages, eight pairs of gills, and a posterior trunk consisting of 8–22 segments. With a fossil record spanning the Silurian to Cretaceous, thylacocephalans have a wide distribution, both in time and space. However, there has been limited examination of specimens from different time periods, and, as such, thylacocephalan systematics remains controversial, preventing a detailed study on their evolution and diversification. One period that requires further study is the Carboniferous. Almost all known Carboniferous thylacocephalans originate from the USA, including Concavicaris—the most iconic Paleozoic thylacocephalan taxon, which has functioned as a wastebasket genus. Further, there are several Carboniferous thylacocephalan occurrences mentioned in the literature from the USA that have not formally been described. To have a more detailed understanding of Carboniferous thylacocephalan diversity dynamics, as well as underlying evolutionary processes, a thorough systematic review is needed. To rectify this, we performed a detailed review of Carboniferous Concavicaris from the USA. In doing so, we describe a new genus and species, Triangulusinus pustulosus n. gen. n. sp., and present a detailed revision of Concavicaris—a taxon that we split into Concavicaris sensu stricto, Paraconcavicaris, Quadrangulucaris n. gen., and Rotundaparma n. gen. This revision opens new perspectives on the systematics and diversification of thylacocephalans.

UUID: http://zoobank.org/3371e3b9-3b57-4df1-897e-37cc8be201ce

A suite of Miaolingian to Furongian (i.e., traditional middle-upper Cambrian) trilobites are reported from the Abrigo Formation at exposures along Nugget Canyon and adjacent Peppersauce Canyon, Santa Catalina Mountains, Arizona, USA. These fossils are uncommon in the region because the unit predominantly comprises coarser-grained siliciclastic facies deposited near shoreface settings where fossils are not often preserved. Trilobites include Agnostidae gen. indet. sp. indet. and the ptychoparioids Ehmaniella sp. indet.; Neoblairella sp. indet.; Altiocculus sp. indet.; Arapahoia ransomei (Stoyanow, 1936); Bolaspidella sp. indet.; Bolaspididae gen. indet. sp. indet.; Brachyaspidion sp. indet.; Cedaria sp. indet.; Crepicephalus sp. indet.; Elburgia sp. indet.; Eldoradia linnarssoni (Walcott, 1884); Eldoradia prospectensis (Walcott, 1884); Iddingsia sp. indet.; Modocia centralis (Whitfield, 1877); Modocia cf. M. crassimarginata Rasetti, 1965b; Modocia oweni? (Meek and Hayden, 1861); Strigambitus cf. S. transversus Palmer, 1965; and Tricrepicephalus texanus (Shumard, 1861). The type specimens of Arapahoia ransomei and Arapahoia butleri (Stoyanow, 1936) are refigured and considered synonymous. This fauna spans the Ehmaniella to Crepicephalus biozones and the Dunderbergia Biozone; the last has not been previously reported from the Abrigo Formation. This biostratigraphy is calibrated by correlation with regional strata constrained by detrital zircon U-Pb geochronology, which provides ages that are consistent with the observed biozones. Considered together, these data help correlate the Abrigo Formation to more fossiliferous and offshore successions elsewhere in Arizona, Sonora, New Mexico, Texas, USA, and beyond.