The sponges may be the oldest group of Metazoa, with a long and successful evolutionary history. Despite their intermittent fossil record quality, the group has been considered reliable for paleoecological and paleobiogeographic analyses because they have inhabited various types of aquatic environments, forming a significant part of benthic communities. We have presented a detailed description of a new species from the genus Teganiella, Teganiellafinksi new species, which expands the chronologic range and classifies the genus as endemic to the paleoequatorial regions of Laurentia associated with arid climate conditions linked to hypersaline periods. Combining the paleoecological and paleo-environmental features of the Teganiella species, our findings also suggest a trend toward more closed-inlet conditions, which may be related to competition and/or specific habitat supplies, for example, heavy metals such as vanadium, zinc, and molybdenum.

Agetolites is a problematic Late Ordovician genus possessing traits of both tabulate and rugose corals. The presence of numerous mural pores has often been considered to indicate a relation to tabulates, although an affinity to rugosans has also been proposed, based mainly on well-developed septa that alternate in length. To further consider the taxonomic position of Agetolites, growth characteristics of coralla representing three species from the Xiazhen Formation in South China are documented and assessed, focusing on modes of corallite increase. Three major modes of increase are recognized. By far the most common mode involves the development of an offset from a connective mural pore, without a clear relationship to a particular parent corallite. This mode of increase is usually associated with corner pores, but in one case occurs at a wall pore. The lateral mode of increase, which is relatively uncommon, is a typical feature in corallites along the boundary of intergrowths with stromatoporoids. The axial mode of increase is rare, occurring during rejuvenation of a damaged corallite or during regeneration following termination of a corallite. The mode of corallite increase that is characteristic of Agetolites, involving a connective mural pore and occurring without evidence of a particular parent, supports the interpretation that this genus is not a rugosan or a typical favositid tabulate. Mural pores are unknown in rugosans, and offsets arise from distinct parent corallites in favositids. The Ordovician genus Lichenaria, considered a representative of the most primitive stock of tabulate corals, shows the closest similarities with types of increase in Agetolites. Certain aspects of lateral and axial increase in Agetolites are comparable to features in a few more genera of Ordovician tabulates, further supporting a tabulate affinity. The phylogenetic relation of Agetolites to those and other tabulate genera, however, remains unresolved.

The rugose corals described in this study were collected from the Gyanyima section in the Ngari region of southwestern Tibet (Xizang) and are assigned to three genera and 11 species, including a new genus and seven new species: Waagenophyllum (Waagenophyllum) ngariense He, 1990; W. (W.) elegantulum He in Luo et al., 1989; W. (W.) minutum Zhao, 1981; W. (W.) tachtabulasicumIlyina, 1997; W. (W.) gyanyimaense n. sp., W. (W.) intermedium n. sp., Waagenophyllum (Liangshanophyllum) clisicolumellum n. sp., Ipciphyllum naoticum n. sp., I. floricolumellum n. sp., I. zandaense n. sp., and Gyanyimaphyllum crassiseptatum n. gen. n. sp. Ontogeny and intraspecific variation are given special attention when describing and discussing these taxa. Coral reefs, with Waagenophyllum as the major skeletal reef builder, occur in several horizons in the uppermost part of the section. The accompanying foraminifers indicate the rugose coral fauna is a late Permian Changhsingian age. Therefore, this is possibly one of the latest Permian rugose coral reefs in the world known up to now.

Permian faunal affinity in the Lhasa Block plays a critical role in reconstructing its paleogeographic evolution. Cisuralian and Guadalupian faunas have been described from the Lhasa Block, but very few Lopingian (late Permian) brachiopods have been reported so far. In this paper, a new diverse brachiopod fauna consisting of 17 species of 17 genera and an unidentifiable Orthotetoidea is described from the uppermost part of the Xiala Formation at the Aduogabu section in the central part of the Lhasa Block. The age of this fauna can be assigned to the Changhsingian (late Lopingian) as indicated by the associated foraminifers Colaniella parva (Colani, 1924) and Reichelina pulchraMiklukho-Maklay, 1954. Characteristic brachiopods include Spinomarginifera chengyaoyenensisHuang, 1932, Haydenella wenganensis (Huang, 1932), and Araxathyris cf. dilatatusShen, He, and Zhu, 1992. They also generally suggest a Changhsingian age. Paleobiogeographically, this fauna is uniformly composed of typical Tethyan elements represented by SpinomarginiferaHuang, 1932 and HaydenellaReed, 1944, and some cosmopolitan elements, but no typical cold-water taxa of Gondwanan affinity. This is in contrast to the contemporaneous brachiopod faunas from the Tethys Himalayan region that are characterized by typical cold-water taxa of Gondwanan affinity, e.g., Costiferina indica (Waagen, 1884), Retimarginifera xizangensisShen et al., 2000, Neospirifer (Quadrospina) tibetensisDing, 1962. Thus, it is strongly indicative that the Lhasa Block had drifted into a relatively warm-water regime during the Changhsingian. An analysis of the paleobiogeographic change of brachiopods in the Lhasa Block throughout the entire Permian further suggests that the Lhasa Block probably had rifted away from the northern peri-Gondwanan margin between the latest Cisuralian and middle Guadalupian, that is, the Neotethys Ocean had opened before middle Guadalupian.

Seven species belonging to the gastropod family Volutidae are reported for the first time from Kutch, Gujarat, India. They are Prestrombus aff. Prestrombus rockeiCox, 1931, Indovoluta humberti (d'Archiac and Haime, 1854), Indovoluta multidentata (d'Archiac and Haime, 1854), Involuta daviesiCox, 1931, Involuta coxi new species, Athleta (Volutocorbis) harnaiensisCox, 1931, and Lyria cf. Lyria punjabensisEames, 1952. Indovolutinae new subfamily, constituted of the Paleogene genera PrestrombusDouvillé, 1929, IndovolutaEames, 1956, InvolutaCox, 1931, and LyrischapaAldrich, 1911, and the Cretaceous genus GosaviaStoliczka, 1865, is proposed. These forms have elaborate development of columellar plaits. All of these genera evolved in the western part of the Indian subcontinent. They, except Lyrischapa, also largely remained restricted to this area. Lyrischapa flourished in the Americas after possibly migrating through the southern margin of the relict Tethys Ocean and crossing the Atlantic Ocean. It is argued that the geographic and temporal restriction of this new subfamily was due to lecithotrophic larval development.

Gastropods of the southwestern Atlantic genus AntistreptusDall, 1902 from extant and Neogene deposits are reviewed. Fossil specimens come from the Punta Entrada Member of the Monte León Formation (50°21′25.4″S, 68°53′05.9″W). Extant samples are from museum collections and two expeditions on board the R/V “Puerto Deseado” to Burdwood Bank (54°13.934′S, 66°30.997′W) and surroundings. Dissection of soft parts and study of the type material of A. magellanicusDall, 1902, Euthria (Glypteuthria) contrariaStrebel, 1908, and A. rolaniCastellanos, 1986 reveal that the latter two nominal species are synonymous. Neogene material assigned to the same genus could not be distinguished as a different species. According to the stratigraphic occurrence of the fossil material, the life-span of the genus AntistreptusDall, 1902 and the species A. magellanicusDall, 1902 is ∼22 Myr, similar to that of the bivalve Cyclochlamys argentinaPastorino and Griffin, 2018.

Knowledge on Early Jurassic marine fossil invertebrates from Argentina is very uneven. Particularly, faunas from Chubut Province received less attention and were thought to be poorer than those from the Neuquén Basin. Nevertheless, an updated revision of bivalves shows that some groups, such as the Protobranchia, were relatively more diverse in Chubut than in Neuquén during late Pliensbachian–early Toarcian times. Only four species are known from the southern areas of the Neuquén Basin, while seven species (three of them new) are here described from Chubut, belonging to the families Nuculidae, Nuculanidae, Polidevciidae, and Malletiidae. The new species are: Palaeonucula feruglioi n. sp., Ryderia tehuelchana n. sp., and Phaenodesmia? piatnitzkyi n. sp. The material is well preserved and allows a detailed analysis of their hinge regions and other internal characters. The presence in Chubut of Palaeoneilo? patagonidica (Leanza) is confirmed, which, along with Praesaccella ovum (Sowerby), are the only two species in common with the Neuquén Basin. The new species Ryderia tehuelchana, belonging to a genus that had a wide global distribution between Rhaetian and Toarcian times, but which was known from South America only for upper Triassic deposits, is of special paleobiogeographic interest. These bivalves are restricted to normal marine environments, and due to their detritivorous feeding habits they only live in organic-rich bottoms as very active shallow burrowers.

The Late Pennsylvanian (Kasimovian, early Stephanian) sub- to perimontaneous Souss basin, situated in the present-day southwestern High Atlas mountains of Morocco, contains the hitherto only known late Paleozoic entomofauna from North Africa, which is simultaneously also the southernmost Euramerican entomofauna. The present study provides descriptions, identifications, and revisions of several species belonging to the genera Phyloblatta and Anthracoblattina (family Phyloblattidae) and of the genus Compsoblatta (family Compsoblattidae). A relatively large number of well-preserved Phyloblatta forewings, compared with congeneric species from several insect localities in Europe and North America, permits insights into the individual, intraspecific, and interspecific variability of the venation pattern as indispensable base for the description of the new specimens and the revision of several older species. The Souss insect beds cover a wide range of potential habitats. They are situated in different paleogeographical positions within the Souss basin and scattered across a 900 m thick succession of sediments. The single insect beds represent different sedimentary and biotic subenvironments from swamps and mires to shallow and deep lakes within a fluvial-dominated megaenvironment.

Using polarized light microscopy, the large, triangular or cylindrical second brachial plate of the Petalocrinidae is demonstrated to be a compound brachial formed through fusion of brachial plates along the distal margin of the growing arms. Based on the number of ambulacral bifurcations, brachials from the primibrachitaxis through at least the quintibrachitaxis may have been fused to form this large plate. In Petalocrinus, fused brachials form a second brachial that assumed the same crystallographic orientation, but in Spirocrinus, multidirectional extinctions preserve some of the original multiplate arrangement.

A new locality for low-latitudinal, Early Triassic fishes was discovered in the Candelaria Hills, southwestern Nevada (USA). The fossils are derived from the lower Candelaria Formation, which was deposited during the middle–late Dienerian (late Induan), ca. 500 ka after the Permian-Triassic boundary mass extinction event. The articulated and disarticulated Osteichthyes (bony fishes), encompassing both Actinistia (coelacanths) and Actinopterygii (ray-fins), are preserved in large, silicified concretions that also contain rare coprolites. We describe the first actinopterygians from the Candelaria Hills. The specimens are referred to Pteronisculus nevadanus new species (Turseoidae?), Ardoreosomus occidentalis new genus new species (Ptycholepidae), the stem neopterygian Candelarialepis argentus new genus new species (Parasemionotidae), and Actinopterygii indet. representing additional taxa. Ardoreosomus n. gen. resembles other ptycholepids, but differs in its more angulate hyomandibula and lack of an elongate opercular process. Candelarialepis n. gen. is one of the largest parasemionotids, distinguished by its bipartite preopercle and scale ornamentation. Presented new species belong to genera (Pteronisculus) or families (Ptycholepidae, Parasemionotidae) that radiated globally after the mass extinction, thus underlining the striking similarities between Early Triassic (pre-Spathian) osteichthyan assemblages. The current data suggest that the diversity of low-latitudinal, Early Triassic bony fishes may have been greater than indicated thus far by the fossil record, probably due to sampling or taphonomic failure. All 24 fossils from the Candelaria Hills represent mid-sized or large osteichthyans, confirming the obvious absence of very small species (≤ 10 cm adult body length) in the beginning of the Mesozoic Era—even in low latitudes.

The recent 2014–2017 controlled excavations carried out in quarries of Sverdlovsk and Tyumen regions, Ural and Western Siberia, are contributing to the knowledge of the middle to late Eocene marine fauna from the Turgay Strait, mainly composed of invertebrates and cartilaginous and bony fishes. Here we present a preliminary report of the bony fishes collected during the campaigns carried out in two Eocene Trans-Urals localities. The sediments of these localities were deposited in a large epicontinental marine basin during the middle to late Eocene, when the Turgay Strait connected the Arctic waters to the North and the Peritethys to the South. Most of the bony fish material examined can be assigned to codfishes (Gadiformes) according to morphological comparison with living and fossil taxa. In particular, nearly complete three-dimensionally preserved lower jaws are confidently assigned to the Merlucciidae, whereas isolated vertebrae and bones are referred to as Gadiformes incertae sedis. This report documents the easternmost occurrence of this group of fishes in the northern hemisphere during the early phases of their radiation, revealing their presence into the Turgay Strait before its closure.

Large body sizes among nonavian theropod dinosaurs is a major feature in the evolution of this clade, with theropods reaching greater sizes than any other terrestrial carnivores. However, the early evolution of large body sizes among theropods is obscured by an incomplete fossil record, with the largest Triassic theropods represented by only a few individuals of uncertain ontogenetic stage. Here I describe two neotheropod specimens from the Upper Triassic Bull Canyon Formation of New Mexico and place them in a broader comparative context of early theropod anatomy. These specimens possess morphologies indicative of ontogenetic immaturity (e.g., absence of femoral bone scars, lack of co-ossification between the astragalus and calcaneum), and phylogenetic analyses recover these specimens as early-diverging neotheropods in a polytomy with other early neotheropods at the base of the clade. Ancestral state reconstruction for body size suggests that the ancestral theropod condition was small (∼240 mm femur length), but the ancestral neotheropod was larger (∼300–340 mm femur length), with coelophysoids experiencing secondary body size reduction, although this is highly dependent on the phylogenetic position of a few key taxa. Theropods evolved large body sizes before the Triassic–Jurassic extinction, as hypothesized in most other ancestral state reconstructions of theropod body sizes, but remained rare relative to smaller theropods until the Jurassic.