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.

UUID: http://zoobank.org/d8c63f6a-0ef4-4a34-8dbd-c1d9099589cc

The upper Bartonian–Priabonian shallow-marine deposits in the Biga Peninsula (NW Turkey) contain some hyaline larger benthic foraminifers (LBF) with a test architecture similar to ‘orbitoidiform’ foraminifers, but displaying some distinctive and complex morphological features that are recorded here for the first time. These coarsely porous specimens are characterized by a flat, disc-shaped, fragile, and smooth test with a layer of equatorial chambers/chamberlets, surrounded by poorly developed lateral chamberlets, never forming a discrete layer on either side of the equatorial layer. The nepionic stage is very distinctive because the bilocular embryonic apparatus is followed by a semi-rounded, notably large auxiliary chamber with a characteristic wavy outline, and consecutive cyclical chambers. The cyclical chamber arrangement is later transformed into annular cycles with numerous, complex arcuate- to cup-shaped chamberlets, as observed in equatorial sections. Bigaella orbitoidiformis Özcan, Mitchell, Pignatti, Simmons, and Yücel, n. gen. n. sp., is established for these specimens, and placed within the family Eoannulariidae Ferràndez-Cañadell and Serra-Kiel, emended herein. The new genus occurs together with Caudriella Haman and Huddleston and Epiannularia Caudri (both originally established from the American bioprovince) and the genus Linderina Schlumberger (found both in the Tethys and the American bioprovinces), together with other typical Western Tethyan LBFs. A comparison of the new genus with the aforementioned taxa is given.

UUID: http://zoobank.org/ab917e30-86d3-4bc2-8115-d17cf75f5d79.

The last clade-level extinction episode affecting the Phylum Brachiopoda has been long-established in the Early Toarcian Mass Extinction Event (ETMEE) around the Pliensbachian-Toarcian transition, when several rhynchonellide groups became extinct and others underwent a notable renewal in the western Tethys. Among them, Wellerelloidea is a long-ranging superfamily severely affected by this environmental crisis, embodying the subfamily Cirpinae as the last wellerelloids worldwide, prior to their global extinction in the Pb-To transition. The profuse record of Lower Jurassic cirpines in the peri-Iberian paleomargins provides an opportunity to clarify the taxonomy of wellerelloid species in the pre-extinction interval. A new species (Cirpa lucentina) is erected and the revision of the Cirpinae taxa around the ETMEE is carried out. Morphometric analysis and the study of internal structures of the shells support separation of the genera Cirpa and Salgirella, adding new supplementary diagnostic criteria. The biogeographic distribution of this clade in the western Tethys and its evolutionary history in the Early Jurassic reveal a pervasive colonization pattern of both epicontinental and epioceanic habitats. The Mediterranean origin of the last representatives of this group is ascertained, but while diversification of Salgirella took place in epioceanic habitats, speciation of Cirpa is unrelated to biochorema boundaries, even colonizing epicontinental seas until their extinction prior to the hyperwarming event that occurred in the basal Serpentinum Zone. A rhynchonellide morphogroup epitomized by cirpines was resilient to this event in the epicontinental seas. This morphogroup is also recorded after the extinction interval by means of the genus Pseudogibbirhynchia, thus postulating potential pre- and post-extinction phyletic relationships.

UUID: http://zoobank.org/100b06c0-a803-4f6f-b0fa-2d9e2d6678d2

Lobopodians are an iconic and diverse group of animals from the Cambrian, which alongside radiodonts, present an important window into the evolution of arthropods and the development of Paleozoic ecosystems. Of these, a rare few species outside of Radiodonta possess lateral swimming flaps. The recent discovery of Utahnax provided much-needed insight into the evolution of swimming flaps, suggesting that the ventrolateral flaps of Kerygmachela evolved independently from other flap-bearing lobopodians and radiodonts. Here a new pelagic lobopodian species is described, Mobulavermis adustus new genus new species, the first lobopodian to be reported from the Cambrian-age Pioche Shale of Nevada. Mobulavermis adustus was large and possessed more ventrolateral flap pairs than any other known lobopodian or radiodont. It is found to be a close relative of both Kerygmachela and Utahnax, allowing the establishment of the new lobopodian family Kerygmachelidae new family. In addition, an indeterminate euarthropod fossil from the Pioche Formation is described in brief, and the recently described Chengjiang species Parvibellus avatus Liu et al., 2022, thought to have been related to the “gilled lobopodians,” is reinterpreted as a juvenile siberiid lobopodian.

UUID: http://zoobank.org/759c4eb9-ec60-4d5a-8b20-4f115ab79575

Natural history museums house numerous previously undescribed species and unknown information hidden in their collections. We describe lower Carboniferous slit-bearing gastropods (order Pleurotomariida, subclass Vetigastropoda; and family Goniasmatidae, subclass Caenogastropoda) from previously unreported gastropod collections made by Jane Longstaff (Jane Donald), one of the pioneering paleontologists of Paleozoic gastropods in the late nineteenth and early twentieth centuries. The gastropods were collected from the Lower Limestone Formation (Visean, Brigantian) near Dalry, Ayrshire, Scotland. The collection consists largely of microgastropods, many of which are unusually well-preserved including delicate ornament and protoconchs (larval shells). Three new pleurotomariidan species are described—Biarmeaspira heidelbergerae new species, Neilsonia seussae new species, Tapinotomaria longstaffae new species—in addition to seven species belonging to Borestus Thomas, 1940, Stegocoelia (Stegocoelia) Donald, 1889, Stegocoelia (Hypergonia) Donald, 1892, Donaldospira Batten, 1966, and Platyzona Knight, 1945. The caenogastropod-type protoconch is documented for the first time in Hypergonia, which is therefore placed in Goniasmatidae. The new data confirm that Neilsonia Thomas, 1940 (type genus of Neilsoniinae) belongs to Pleurotomariida and is distinct from the morphologically convergent Peruvispira Chronic, 1949 (Goniasmatidae). The selenizone morphology is identical in Biarmeaspira Mazaev, 2006 and Baylea de Koninck, 1883 during their early ontogeny, and Biarmeaspira develops an angulation on the selenizone (the diagnostic feature) in late ontogeny. This corroborates earlier suggestions that Biarmeaspira evolved from Baylea. Biarmeaspira heidelbergerae n. sp. is the first Carboniferous record of Biarmeaspira, which was previously only known from the Permian. The angulated selenizone evidently evolved several times in Pleurotomariida and the repeated appearance of this character in different groups (e.g., Phymatopleuridae, Eotomariidae, Pleurotomariidae) needs further studies using phylogenetic methods.

UUID: http://zoobank.org/92ae9a99-5774-4ee9-bf5d-9a9319494ef6