In 1855, Ferdinand Hayden collected a single tooth from the Judith River badlands of central Montana. Joseph Leidy named this specimen the following year as Troodon formosus. We describe troodontid material from the coeval Two Medicine Formation of Montana that compares closely to the recently resurrected and previously synonymized Stenonychosaurus inequalis from the lower Dinosaur Park Formation of Alberta. We uphold that synonymy but recognize T. formosus as the senior synonym. Troodon formosus is distinguished from other troodontids by a maxilla with an anteriorly more broadly rounded maxillary fenestra, low-angled nasal process with stepped anterior portion, large palatal shelf, and 23 teeth; more pronounced basioccipital tubera; L-shaped to triangular frontal; and relatively shorter metatarsal III with convex to flat anterior face at maximum breadth. Phylogenetic analysis places T. formosus within the Troodontinae, a clade with poor within-group resolution. The T. formosus holotype was diagnostic at time of description. Despite numerous complications over the taxon’s long history, the original name of 1856 has come to encompass a robust and specific species concept despite originally fragmentary material. Troodon formosus best satisfies the International Code of Zoological Nomenclature’s tenants of priority and stability. Recent proposals to re-establish Stenonychosaurus inequalis as the proper name encounter an equally problematic and undiagnostic type specimen. Instead of either of these types, we propose that material from the Two Medicine Formation (Museum of the Rockies, MOR 553) would best serve as a neotype for Troodon formosus.

Previous typification acts are reviewed herein, in light of the International Code of Zoological Nomenclature, to correct improper procedures while raising new type specimens for Theriosynoecum silvai, Darwinula martinsi and Cypridea araripensis, after loss of the original ones.

The brachyurans Tehuacana tehuacana Stenzel, 1944 and Dromilites americana Rathbun, 1935 have historically been difficult to place in families. A reevaluation of type and referred material from several institutions suggests that the two species are referrable to separate genera in Palaeoxanthopsidae. Hyphalocarcinus new genus is erected to accommodate H. americanus new combination, and Tehuacana remains a distinct genus. Palaeoxanthopsidae evolved and radiated in the Atlantic Ocean, ranging from Late Cretaceous (Maastrichtian) to early Eocene (Ypresian) in age. This work adds to the known diversity of Palaeoxanthopsidae and demonstrates that the family survived and thrived in the Atlantic Ocean in the wake of the end-Cretaceous extinction. Differential preservation of specimens must be evaluated carefully when placing superficially similar taxa at the family, genus, and species level.

UUID: http://zoobank.org/73da26c7-aff7-4abe-8aa5-768944bbf6ee

Early Miocene land mammals from eastern North America are exceedingly rare. Over the past several decades a small, but significant, vertebrate fauna has been recovered by paleontologists and citizen scientists from the Belgrade Formation at the Martin Marietta Belgrade Quarry in eastern North Carolina. This assemblage has 12 land mammal taxa, including beaver (Castoridae), stem lagomorph, carnivorans (Mustelidae, Ailuridae), horses (Equidae), rhinoceros (Rhinocerotidae), tapir (Tapiridae), peccary (Tayassuidae), anthracothere (Anthracotheriidae), entelodont (Entelodontidae), and protoceratid (Protoceratidae). Taken together, the biochronology of this Maysville Local Fauna indicates a late Arikareean (Ar3/Ar4) to early Hemingfordian (He1) North American Land Mammal Age (NALMA). This interval, which includes the Runningwater Chronofauna, documents numerous important Holarctic immigrants, including Amphictis, Craterogale, and cf. Menoceras found at this locality. Strontium isotope stratigraphy (SIS) of shark teeth collected in situ from the Belgrade Formation yield an age of 21.4 ± 0.13 Ma, which validates the age of interbedded land mammals within this unit. It also is consistent with the late Arikareean (Ar3/Ar4) biochronology and Aquitanian Neogene marine stage. New SIS analyses of oysters (Striostrea gigantissima) and clams (Chione) from this mine, previously assigned to late Oligocene or Late Miocene, are significantly older (28.0 ± 0.22 Ma and 27.6 ± 0.26 Ma, respectively) than the land mammals. Depending upon stratigraphic interpretations, these may confirm an older marine facies within the Belgrade Formation. This locality is important because of its marine and terrestrial tie-ins that facilitate intercalibration of both NALMAs and Cenozoic marine stages.

According to the International Code of Zoological Nomenclature (ICZN, 1999), the Principle of Homonymy (Article 52) states that when two or more taxa are distinguished from each other, they must not be denoted by the same name because this would cause confusion. Consequently, in a case of homonymy, only the senior name may be used as valid (Art. 52.2). The ICZN (1999) also indicates that if the rejected junior homonym has no known available and potentially valid synonym, it must be replaced by a new substitute name (Art. 60.3), that is, a replacement name.

A highly diversified fauna of brachyurans is described from the lower Eocene Serraduy Formation of Huesca, northeastern Spain. Fifteen new and first-reported taxa of brachyurans are described including three new genera, ten new species, and five taxa in open nomenclature. New taxa include: Carpilius feldmanni n. sp., Ceronnectes rugosus n. sp., Eohexapus simplex n. sp., Galenopsis ossoi n. sp., Matutsalen rotundus n. gen. n. sp., Microboschettia elegans n. gen. n. sp., Parhalimede antiqua n. sp., Locomius parthenopimimus n. gen. n. sp., Liocarcinus tridentatus n. sp., and Xanthilites robustus n. sp. Five additional genera have been recognized from fragmented material only including Alponella sp., Lovaroides sp., Paromola sp., ?Rhinolambrus sp., and ?Spinirostrimaia sp. Moreover, based on new specimens, we provide new data on Ilerdapatiscus guardiae and Aragolambrus collinsi. New information supports previous considerations about reef settings that are comparable to modern reef ecosystems as environments of diversified decapod crustaceans in the early Eocene.

UUID: http://zoobank.org/a5426acb-1d14-4e37-a843-922c940ac5b2

Well-preserved specimens of the xanthid crab Lathahypossia aculeata (Busulini, Tessier, and Visentin, 1984) coming from middle Eocene volcanoclastites at Main quarry (Vicenza, Northeast Italy) are housed in three Museums in the Veneto region. Their exoskeletons, mainly chelipeds and thoracic sternum, are significantly encrusted by serpulid tubes assigned to the new species Propomatoceros lathahypossiae. Serpulids belong to the genus Propomatoceros, which has until now ranged from the Triassic to the Cretaceous; this record of the genus is the first in the Cenozoic. The abundance, frequency, and distribution pattern of the serpulid specimens on the different parts of the exoskeleton of the crabs were investigated, shedding light on the ecology/behavior of the encrusting species. Finally, the settlement and growth of serpulids related to sex, size, and molting cycle of the crabs were discussed, hypothesizing on the type of symbiotic relationship among the encrusters and their host.

http://zoobank.org/874be464-8bbf-46dc-8ed7-e7d0112d02b9

A late Eocene (Priabonian) decapod crustacean (Arthropoda: Malacostraca: Decapoda) faunule from the sandstones and siltstones of the Tomášovce Member (Borové Formation) of northern Slovakia (Western Carpathians) is presented. Several decades of collecting at the Ďurkovec quarry in the Spišská Nová Ves district, the stratotype locality of the Tomášovce Member, yielded four decapod species, including an axiidean shrimp Ctenocheles sp. indet. (Ctenochelidae), and three brachyuran crabs Amphoranina hazslinszkyi (Reuss, 1859) new combination (Raninidae), Calappilia tridentata (Beurlen, 1939) (Calappidae), and Coeloma vigil A. Milne-Edwards, 1865 (Polybiidae). The faunule is dominated by A. hazslinszkyi and Coeloma vigil. The specimens often represent more-or-less intact individuals with preserved claws and walking legs, suggesting rapid burial and minimal to no postmortem transport. Additionally, specimens of A. hazslinszkyi are in some cases preserved perpendicularly to the bedding planes and interpreted as being covered by large amount of sediment while being buried in the substrate, causing death of the animals. The presence of trace fossils assigned to Thalassinoides Ehrenberg, 1944 are indirectly linked with the burrowing shrimp Ctenocheles sp. indet. The decapod faunule inhabited a shallow marine environment with the depth likely not exceeding 100 m.

From re-examination of the type and additional specimens of Munida nishioi Karasawa, 1993 and Kazuoia ogaensis Hatai and Kotaka, 1970 from the Miocene deposits of Japan, both species are assigned to Grimothea Leach, 1821 [1820] of the squat lobster family Munididae Ahyong et al., 2010. The revised diagnosis and description are given for Grimothea nishioi (Karasawa, 1993) new combination and Grimothea ogaensis (Hatai and Kotaka, 1970) new combination. The monotypic genus Kazuoia Hatai and Kotaka, 1970 becomes a junior subjective synonym of Grimothea. Trapezionida chiyoensis new species is described from the lower Miocene of central Japan. These species represent the first records of Grimothea and Trapezionida Macpherson and Baba in Machordom et al., 2022 recognized as fossils.

UUID: http://zoobank.org/5917b8a9-2c16-443f-a64f-964cb78fce16

The Indo-West Pacific region serves as the primary habitat for the majority of extant hexapodid crabs. The hexapodids boast a rich evolutionary history dating back to the Cretaceous, marked by a significant radiation throughout the Cenozoic, while the Paleocene–Miocene of tropical America emerges as a pivotal center of radiation, evidenced by reported hexapodid species in Barbados, Panama, Peru, Trinidad, and Venezuela. Through an examination of the paleocarcinological collection at the Museu Paraense Emílio Goeldi, a new genus and species within Hexapodidae is described and illustrated. Rodneyellus feldmanni, the newly described taxon, is named in honor to Dr. Rodney Feldmann for his unwavering commitment to fossil crustacean research. This report marks the inaugural documentation of Hexapodidae in Brazil, encompassing both fossilized and extant representatives. Furthermore, the Pirabas Formation emerges as a critical locus for comprehending the contemporary distribution of decapod crustaceans across tropical America.

UUID: http://zoobank.org/9792bc1e-d06e-490b-a8e6-c23ee1c11fb1