Despite the abundance and diversity of Venericardia bivalves on the U.S. Coastal Plain during the Paleogene, the evolutionary relationships within the genus remain unresolved. The primary objectives of this study were to reconstruct a phylogeny of Venericardia species, identify major clades within the genus, and determine whether groupings within traditional venericard classifications constitute monophyletic taxa. Fifty-one conchological characters were applied to 18 venericard and two outgroup species. Parsimony analysis produced three equally parsimonious trees and robustness was assessed through Bremer support and bootstrap values. The resultant trees indicate that the smooth-ribbed planicostate venericards are monophyletic, whereas the sharp-ribbed alticostate venericards are paraphyletic. Additionally, the original planicostate subtaxon, Venericor, is monophyletic whereas the original alticostate subtaxa, Claibornicardia, Glyptoactis, and Rotundicardia, are nonmonophyletic.

The first mastotermitid termite from Africa is described and figured from wing fragments recovered from the early Miocene (22–21 Ma) deposits of the Mush Valley, Amhara Region, central Ethiopia. Mastotermes aethiopicus new species is the second fossil termite recorded from Africa and expands the known paleo-distribution of the genus from tropical North America and Europe into northeastern Africa during the Miocene. Mastotermes aethiopicus is distinguished from the living M. darwiniensis Froggatt and other Neogene species of the genus, and comments are provided regarding the occurrence of this genus in the tropical fauna of Miocene Ethiopia.

Historically, the whaitsiid therocephalian Theriognathus Owen was one of the earliest described nonmammalian therapsids, its morphology helping to link phylogenetically the Paleozoic synapsids of North America and southern Africa to their mammalian successors. However, decades of taxonomic over-splitting and superficial descriptions obscured the morphologic diversity of the genus, hindering its utility as a study system for the evolution of synapsid cranial function as well as its biostratigraphic significance in the Late Permian of southern Africa. Here, we revise the status and provenance of all the known specimens of Theriognathus from South Africa, Tanzania, and Zambia. We present both qualitative and quantitative support for the presence of a single morphospecies as proposed by some authors. Proportional differences in skulls that were previously ascribed to different morphotypes (‘Aneugomphius,’ ‘Notosollasia,’ ‘Moschorhynchus,’ and ‘Whaitsia’) are largely size-related and allometric trends are considered here in the context of jaw function and prey prehension. Our results suggest that the single species, Theriognathus microps, represented one of the most abundant Late Permian therocephalians in southern Africa and is consequently a potentially useful biostratigraphic marker for the upper Cistecephalus-lower Dicynodon Assemblage Zone transition (i.e., late Wuchiapingian). The wide range of preserved sizes in conjunction with recent paleohistological evidence supports that individuals spent much of their lives in an actively-growing, subadult phase. Later Dicynodon Assemblage Zone records (e.g., upper Balfour Formation) are unconfirmed as the genus was likely replaced by other theriodont predators (e.g., Moschorhinus) leading up to the Permo-Triassic boundary in the Karoo Basin of South Africa.

The bryozoan family Chlidoniopsidae Harmer, 1957 is reviewed in relation to a new Paleogene European fossil, Celiopsis vici new genus and new species. It differs from the type and only other genus of the family in having longer internodes with up to three zooids, shorter proximal caudae, and, more importantly, suture lines that unequally divided the umbonuloid frontal shield and basal (abfrontal) wall (and the hypostegal coelom in life) into sectors, analogous to the situation in the lepralioid-shielded Prostomariidae and Urceoliporidae. Unlike Prostomaria and Urceolipora, and like Chlidoniopsis, Celiopsis is uniserial. The suture lines in Celiopsis were lines of insertion (attachment) of epithecal membranes in life and each sector has its own longitudinal series of septular pores, sometimes doubled. Miocene to Recent Chlidoniopsis contains two species, and Eocene–Oligocene Celiopsis contains three species. The geographic distribution gives evidence of origination of the family in the Paratethys of Europe, with southeastwards migration to Australia and the tropical western Pacific. The temporal distribution suggests two macro-evolutionary trends—from multizooidal to unizooidal internodes, and from a broader area of basal wall, with a division into separate cryptocystal fields, to a narrower basal wall with no such division.

Remingtonocetidae are Eocene archaeocetes that represent a unique experiment in cetacean evolution. They possess long narrow skulls, long necks, fused sacra, and robust hind limbs. Previously described remingtonocetids are known from middle Eocene Lutetian strata in Pakistan and India. Here we describe a new remingtonocetid, Rayanistes afer, n. gen. n. sp., recovered from a middle to late Lutetian interval of the Midawara Formation in Egypt. The holotype preserves a sacrum with four vertebral centra; several lumbar and caudal vertebrae; an innominate with a complete ilium, ischium, and acetabulum; and a nearly complete femur. The ilium and ischium of Rayanistes are bladelike, rising sharply from the body of the innominate anterior and posterior to the acetabulum, and the acetabular notch is narrow. These features are diagnostic of Remingtonocetidae, but their development also shows that Rayanistes had a specialized mode of locomotion. The expanded ischium is larger than that of any other archaeocete, supporting musculature for powerful retraction of the hind limbs during swimming. Posteriorly angled neural spines on lumbar vertebrae and other features indicate increased passive flexibility of the lumbus. Rayanistes probably used its enhanced lumbar flexibility to increase the length of the power stroke during pelvic paddling. Recovery of a remingtonocetid in Egypt broadens the distribution of Remingtonocetidae and shows that protocetids were not the only semiaquatic archaeocetes capable of dispersal across the southern Tethys Sea.

Trochotomidae is a small but distinctive extinct family of pleurotomarioidean gastropods characterized by trochiform shells with an elliptical trema. Two new species of trochotomids are described from Pliensbachian deposits in the Neuquén Basin, Argentina. The new genus-group name Placotoma is proposed to replace the pre-occupied name Discotoma Haber non Mulsant. The record of Trochotoma (Trochotoma) protonotialis new species and Trochotoma (Placotoma) neuquensis new species in the early Jurassic of Argentina extends the paleobiogeographical distribution of the genus (and the family) to the Southern Hemisphere. The new taxa reported here represent a component of the pleurotomarioidean adaptive radiation that took place in the Tethyan region during the earliest Jurassic. They are related to local patch coral reefs of shallow, open-marine paleoenvironments, agreeing with the known habitat of most species of this family. The group was well represented in the Tethyan region during the Mesozoic, especially during the Jurassic, and the new species represent its southernmost occurrence.

The new edrioasterine Pseudedriophus guensburgi n. gen. n. sp., is described from the Lower Ordovician Ninemile Shale of central Nevada based on three complete to partial small specimens, a well-preserved large ambulacrum, and an isolated ambulacral floor plate. The weathered-out holotype of this edrioasterine exposes the bottom surface of the theca that bears an aboral collar, peduncular stalk, and attachment disk, features that are poorly known in this clade. These specimens were found with a single specimen of a new edrioblastoid, Porosublastus inexpectus n. gen. n. sp., only the second edrioblastoid ever found in the Early Ordovician. Some of the ambulacral cover plates are stripped off one of the ambulacal grooves, revealing new information about how the ambulacra are built in this rare group of bud-shaped edrioasteroids.

Gladius-bearing coleoids are rare in the fossil record. For the Cretaceous period, these cephalopods are mainly recorded in a few Lagerstätten in Lebanon (Haqel, Hajoula, En Nammoura, and Sahel Aalma). Here, we study 16 specimens of gladius-bearing coleoids from these Upper Cretaceous Lebanese Lagerstätten to investigate their taxonomic diversity. Besides two species that were already reported (Dorateuthis syriaca and Glyphiteuthis libanotica), one new species is identified in the Cenomanian site of Hajoula: Rachiteuthis acutali n. sp., as well as another form of Glyphiteuthis from En Nammoura. Several studied specimens exhibit well-preserved soft-part characters. Among them, we document for the first time two transverse rows of sessile suckers in D. syriaca and we confirm the absence of tentacles, as well as the presence of a crop in this species. This strongly supports the phylogenetic proximity of D. syriaca with modern vampyropods rather than with modern decabrachians. In turn, the similarity in gladius morphology between this taxon and modern squids is regarded as convergent.

Species-level diversity and evolution of Palaeosinopa from the Willwood Formation of the Bighorn Basin is reassessed based on substantial new material from the Bighorn, Powder River, and Wind River basins. We recognize three species of Palaeosinopa in the Willwood Formation of the Bighorn Basin: P. lutreola, P. incerta, and P. veterrima. The late Wasatchian species P. didelphoides is not present in the Bighorn Basin. The Willwood species can be differentiated based only on size. P. veterrima is the most common and wide-ranging species and is the most variable in size and morphology: the stratigraphically lowest individuals are smaller, with narrower, more crestiform lower molars; whereas the highest are larger, with wider, more bunodont teeth. Although it could be argued that these represent distinct species, we demonstrate that this morphological evolution occurred as the gradual and mosaic accumulation of features, suggesting in situ anagenetic evolution. The two smaller species are present only low in the section (biochrons Wa0–Wa4) and show no discernable evolution in size or morphology. A new skeleton of Palaeosinopa veterrima from the Willwood Formation is described, and other new postcrania are reported. The skeleton is the oldest associated skeleton of Palaeosinopa known, yet it is remarkably similar to those of younger, more derived pantolestids, the primary disparities being minor differences in proportions of the innominate, femur, and tibia, and co-ossification of the distal tibia and fibula. Either P. incerta or P. lutreola was likely the ancestral population that gave rise to the other Wasatchian Palaeosinopa. Alternatively, P. veterrima may have migrated into the Bighorn Basin from the Powder River Basin.

The fossil record of Australasian Formicidae is extremely sparse. It currently comprises two ants in the subfamilies Ponerinae and Dolichoderinae from Plio/Pleistocene strata in Victoria, Australia, 14 as-yet undescribed ants from Cape York amber, and one ant in the subfamily Amblyoponinae from the early Miocene Foulden Maar in southern New Zealand. Here, we report on a diverse myrmecofauna preserved as compression fossils from Foulden Maar and describe Amblyoponinae gen. et sp. indet., Rhytidoponera waipiata n. sp., Rhytidoponera gibsoni n. sp., Myrmecorhynchus novaeseelandiae n. sp., and Austroponera schneideri n. sp. Further isolated wings are designated as Formicidae sp. A, B, and C, the former resembling a member of subfamily Dolichoderinae. Fossils of Austroponera and Myrmecorhynchus are reported for the first time, whereas Rhytidoponera waipiata n. sp. and R. gibsoni n. sp. are the first Southern Hemisphere fossil records of this genus.

The fossil taxa from Foulden Maar establish the subfamilies Ectatomminae, Formicinae, Ponerinae and, possibly, Dolichoderinae in the Australasian region in the early Miocene and provide evidence that the few native ants in the extant New Zealand fauna are the surviving remnant of taxonomically different, possibly more diverse, warm-temperate to subtropical myrmecofauna.

Fossil Scydmaeninae beetles are exceptionally poorly known and those described usually lack important details to reliably analyze their phylogenetic relationships with extant taxa. Baltostigus n. gen. is the first extinct ant-like stone beetle taxon unambiguously assigned to the tribe Mastigini. It includes B. antennatus n. sp. (the type species of Baltostigus) and B. horribilis n. sp., from the lower to middle Eocene amber of Poland and Lithuania, respectively. Results of a phylogenetic analysis comprising morphological characters of all extant and extinct genera of the supertribe Mastigitae strongly support the placement of Baltostigus as a sister group to all remaining Mastigini. The new genus shows character states not known in any extant Mastigini: fully developed hind wings, prominent humeral calli, deep elytral punctures partly arranged in longitudinal rows and symmetrical aedeagal parameres. These features suggest that Mastigini might have evolved from forms morphologically similar to small-bodied extant Clidicini of the ‘Leptochromus lineage.’

The ankylosaurine Pinacosaurus is one of the best known ankylosaur to date in terms of the number and preservational quality of specimens. Juvenile to sub-adult postcrania collected by the Soviet-Mongolian Paleontological Expedition from the Upper Cretaceous Alagteeg Formation at Alag Teeg, Mongolia can be assigned to Pinacosaurus grangeri based on discrete cranial characters. One individual is significantly larger than the others and demonstrates delayed fusion of postcranial elements with the earliest occurring between dorsal ribs and vertebrae. The robustness of forelimb elements is positively allometric with respect to their length, indicating weight-bearing relationship. Such length-dependent correlations are not seen in the hind limbs. Finally, incipient cervical half rings suggest a developmental pathway of outgrowths from the underlying band combined with fusion of overlying osteoderms.

An unusual, new, giant edrioasteroid Bizarroglobus medusae n. gen. n. sp. is described from the Middle Ordovician Kanosh Shale of west-central Utah. This species has a pattern of ambulacral branching with side ambulacra arising alternately from a main ambulacral trunk, previously undocumented in edrioasteroids. This pattern is interpreted as a strategy for allometrically increasing the feeding surface during ontogeny. Bizarroglobus further differs from other isorophid edrioasteroids in the plating of the peripheral rim, and the presence of pores in the interambulacral plates primarily along the edges of the ambulacra.