Ammonite research • Evidence indicating that morphologically complex ammonoid taxa often had reduced longevity and higher origination and extinction rates compared to morphologically simple ones is presented by Miao
et al. (2024). • Morón-Alfonso, Allaire & Ginot (2024) compare the results of application of two methods used to analyze the ammonoid whorl profile shape, interpreting different methods as better suited for taxa with highly defined umbilical walls and for ones with smooth umbilical walls or with reduced whorl overlap. • A study on the affinities of
"Tornoceras" baldisi, based on data from new specimens from the Chigua Formation (
Argentina), is published by Allaire
et al. (2024), who transfer this species to the genus
Epitornoceras, and interpret the uppermost levels of the Chavela Member of the Chigua Formation preserving its fossils as
Givetian in age. • Piñeiro, Rodao & Núñez Demarco (2024) describe clusters of tiny ammonite shells from the
San Gregorio Formation (
Uruguay), found in nodules interpreted as reworked from underlying Devonian levels, and interpret this findings as possible evidence that ammonites laid eggs in floating or fixed gelatinous masses and hatched as miniatures of their parents that shared the same habitat with adult ammonites. • A study on the origin of the Permian ammonite superfamily
Popanoceratoidea is published by Leonova (2024). • Description of the Olenekian ammonite assemblage from the Osawa Formation (
Japan), interpreted as indicative of affinities with ammonite faunas from South
Primorye and from the
Tethys, is published by Shigeta, Endo & Inose (2024). • Taxonomic revision of Carnian ammonites from the Polzberg
Lagerstätte (
Austria) is published by Lukeneder & Lukeneder (2024). • Mironenko & Smurova (2024) describe ammonite specimens from the Jurassic localities in
Russia preserved with the three-dimensional
cameral membranes in their
phragmocones which differed in their spatial arrangement and complexity from those known in other ammonites, and study the formation of all types of ammonite cameral sheets. • Mitta & Mironenko (2024) describe a large-sized upper jaw of a member of the genus
Lytoceras from the
Bajocian strata from the Kuban basin (
Karachay-Cherkessia,
Russia), representing the oldest complete jaw of this type and the only upper jaw of a member of
Lytoceratina reported to date. • Sandoval (2024) describes fossil material of
Latiwitchellia evoluta from the Middle Jurassic strata from the Betic Cordillera (
Spain), representing the first known record of this species outside Eastern Pacific, and interprets this finding as indicating that westernmost
Tethys and Eastern Pacific domains were connected through the Hispanic Corridor during the early Bajocian. • The earliest occurrence of genus
Macrocephalites known to date is reported from the
Bathonian Kachchh Basin (
India) by Jain (2024). • Description of Late Jurassic ammonites from the Spiti Shale Formation of the Spiti and Zanskar regions of the Himalayas (India) is published by Bhosale
et al. (2024). • López-Palomino, Villaseñor & Palma-Ramírez (2024) study the affinities of Late Jurassic ammonites from the Santiago Formation (
Mexico), providing evidence of biogeographic affinities with ammonites from
Cuba,
Chile and
Argentina, as well as evidence of existence of the connection between the Tethys Ocean and the Pacific throughout the
Oxfordian. • A study on the relationship between septal complexity and ammonite diversity during the Cretaceous is published by Pérez-Claros (2024), who finds no evidence of a close relationship between oceanic anoxic events throughout the Cretaceous and worldwide evolutionary dynamics of ammonites. • A study on changes of conch shape and
septal spacing between successive
chambers in Cretaceous ammonites from India, Madagascar and Japan throughout their
ontogeny, interpreted as indicative of closer phylogenetic relationships between
Perisphinctina and
Ancyloceratina than with
Lytoceratina or
Phylloceratina, is published by Nishino
et al. (2024). • Frau
et al. (2024) designate the
neotype for the Early Cretaceous ammonite species
Ammonites flexisulcatus, and assign this species to the
desmoceratid genus
Caseyella. • A study on the morphological variation of specimens of
Placenticeras from the Upper Cretaceous strata of the eastern Gulf Coastal Plain (mostly from
Alabama,
United States) is published by Mohr, Tobin & Tompkins (2024), who interpret the studied sample as including either a single species or two successive species, find no support for the recognition of
Placenticeras and
Stantonoceras as distinct genera, and report likely evidence of
sexual dimorphism. • Evidence from oxygen isotope values of shell material of Late Cretaceous ammonites from the
Western Interior Seaway, interpreted as indicative of ~18 °C cooling from the
Cretaceous Thermal Maximum in the
Turonian until the late
Maastrichtian, is presented by McCraw
et al. (2024). • A study on the diversification dynamics of Late Cretaceous ammonites is published by Flannery-Sutherland
et al. (2024), who find evidence of regional differences of diversity trends, but no evidence of a progressive global decline through the Late Cretaceous. ==Other cephalopods==