Fossil evidence for vampire squid inhabiting oxygen-depleted ocean zones since at least the Oligocene.

A marked 120 My gap in the fossil record of vampire squids separates the only extant species (Vampyroteuthis infernalis) from its Early Cretaceous, morphologically-similar ancestors. While the extant species possesses unique physiological adaptations to bathyal environments with low oxygen concentrations, Mesozoic vampyromorphs inhabited epicontinental shelves. However, the timing of their retreat towards bathyal and oxygen-depleted habitats is poorly documented. Here, we document a first record of a post-Mesozoic vampire squid from the Oligocene of the Central Paratethys represented by a vampyromorph gladius. We assign Necroteuthis hungarica to the family Vampyroteuthidae that links Mesozoic loligosepiids with Recent Vampyroteuthis. Micropalaeontological, palaeoecological, and geochemical analyses demonstrate that Necroteuthis hungarica inhabited bathyal environments with bottom-water anoxia and high primary productivity in salinity-stratified Central Paratethys basins. Vampire squids were thus adapted to bathyal, oxygen-depleted habitats at least since the Oligocene. We suggest that the Cretaceous and the early Cenozoic OMZs triggered their deep-sea specialization.

Comprehensive analysis and reinterpretation of Cenozoic mesofossils reveals ancient origin of the snapping claw of alpheid shrimps.

Alpheid snapping shrimps (Decapoda: Caridea: Alpheidae) constitute one of the model groups for inferences aimed at understanding the evolution of complex structural, behavioural, and ecological traits among benthic marine invertebrates. Despite being a super-diverse taxon with a broad geographical distribution, the alpheid fossil record is still poorly known. However, data presented herein show that the strongly calcified fingertips of alpheid snapping claws are not uncommon in the fossil record and should be considered a novel type of mesofossil. The Cenozoic remains analysed here represent a compelling structural match with extant species of Alpheus. Based on the presence of several distinct snapping claw-fingertip morphotypes, the major radiation of Alpheus lineages is estimated to have occurred as early as 18 mya. In addition, the oldest fossil record of alpheids in general can now be confirmed for the Late Oligocene (27-28 mya), thus providing a novel minimum age for the entire group as well as the first reliable calibration point for deep phylogenetic inferences.

New paleocene sepiid coleoids (cephalopoda) from Egypt: evolutionary significance and origin of the sepiid 'rostrum'.

New coleoid cephalopods, assignable to the order Sepiida, are recorded from the Selandian/Thanetian boundary interval (Middle to Upper Paleocene transition, c. 59.2 Ma) along the southeastern margin (Toshka Lakes) of the Western Desert in Egypt. The two genera recognised, Aegyptosaepia n. gen. and ?Anomalosaepia Weaver and Ciampaglio, are placed in the families Belosaepiidae and ?Anomalosaepiidae, respectively. They constitute the oldest record to date of sepiids with a 'rostrum-like' prong. In addition, a third, generically and specifically indeterminate coleoid is represented by a single rostrum-like find. The taxonomic assignment of the material is based on apical parts (as preserved), i.e., guard, apical prong (or 'rostrum-like' structure), phragmocone and (remains of) protoconch, plus shell mineralogy. We here confirm the shell of early sepiids to have been bimineralic, i.e., composed of both calcite and aragonite. Aegyptosaepia lugeri n. gen., n. sp. reveals some similarities to later species of Belosaepia, in particular the possession of a distinct prong. General features of the phragmocone and protoconch of the new form are similar to both Belocurta (Middle Danian [Lower Paleocene]) and Belosaepia (Eocene). However, breviconic coiling and the presence of a longer ventral conotheca indicate closer ties with late Maastrichtian-Middle Danian Ceratisepia. In this respect, Aegyptosaepia n. gen. constitutes a link between Ceratisepia and the Eocene Belosaepia. The occurrence of the new genus near the Selandian/Thanetian boundary suggests an earlier origin of belosaepiids, during the early to Middle Paleocene. These earliest known belosaepiids may have originated in the Tethyan Realm. From northeast Africa, they subsequently spread to western India, the Arabian Plate and, probably via the Mediterranean region, to Europe and North America.