A kogiid sperm whale from the lower Pliocene of the Northern Apennines (Italy)

We report on a new specimen of Kogiidae from S. Andrea Bagni, a Zanclean fossiliferous site of northern Italy. • This specimen consists of a partially complete cranium, one vertebra, one fragment of rib, and one tooth. • The S. Andrea Bagni kogiid is recognized as representative of a new taxon in the subfamily Kogiinae. • Association of this specimen with teeth of deep-water squaloids provides interesting palaeoecological hints

A new kogiid sperm whale from northern Italy supports psychrospheric conditions in the early Pliocene Mediterranean Sea

Among living cetaceans, dwarf and pygmy sperm whales (Kogia) are the only members of the family Kogiidae, regarded as diminutive and elusive relatives of the great sperm whale Physeter. Kogiids are known as fossils by several skulls, teeth, and ear bones from Neogene deposits of the Northern Hemisphere and Peru. We report on a fossil kogiid specimen collected at Sant’Andrea Bagni (northern Italy) from Zanclean marine mudstone; these deposits also yielded a rich deep-water elasmobranch assemblage depicting the presence of Atlantic-derived psychrospheric waters. The kogiid specimen, consisting of a partial cranium, one detached tooth, one vertebra, and one fragmentary rib, is here referred to Pliokogia apenninica gen. et sp. nov. Pliokogia is mostly characterised by a long and dorsally flattened rostrum and by the presence of two well-distinct fossae on the right side of the supracranial basin, including an elongated peripheral maxillary fossa on the posterior portion of the right maxilla. Our phylogenetic analysis recovers Pliokogia as a member of the subfamily Kogiinae, which includes Kogia, Koristocetus, Nanokogia, and Praekogia. A low temporal fossa and the absence of dental enamel suggest that, like extant Kogia, Pliokogia was a suction feeder. Since living kogiids do not inhabit the Mediterranean waters, and considering that they feed on deep-water prey in open-sea areas, the association of Pliokogia with a psychrospheric elasmobranch assemblage with Atlantic affinities is noteworthy. Indeed, in early Pliocene times, the Gibraltar connection was controlled by estuarine dynamics, thus allowing the entrance of deep-water organisms (including the putative prey of Pliokogia) in the Mediterranean Basin. The subsequent abandonment of the Mediterranean Sea by kogiids might therefore be related to the definitive establishment of the present-day antiestuarine circulation at Gibraltar, which likely led to a limited deep nutrient supply and resulted in the strong depletion of most Mediterranean deep-water ecosystems

Additional records of the little sleeper shark, Somniosus rostratus (Elasmobranchii: Squaliformes: Somniosidae), in Mediterranean Sea

This study investigates the distribution and morphometrics of the little sleeper shark, Somniosus rostratus (Risso, 1827), in the Mediterranean Sea. Ten sharks caught as bycatch between 2009 and 2019 in the northern sectors of the Strait of Sicily, the south Tyrrhenian Sea, the northwestern Ionian Sea, and the south Adriatic Sea using drifting longlines, as well as five retrieved from the Tripoli (Libya) marketplace, were morphologically confirmed to represent S. rostratus. The sharks exhibited typical characteristics for this species and were all caught from deep waters, indicating a potential mesopelagic habit. The study also utilized literature reviews and global databases for a comprehensive mapping of S. rostratus distribution in the Mediterranean Sea, which revealed sporadic occurrences in the eastern Mediterranean and an absence in the north Adriatic Sea. Morphometric data provided insights into the reproductive characteristics of S. rostratus. The study highlights the ecological significance of the Strait of Sicily (Central Mediterranean Sea) for the species, indicating it as a likely spawning area, and underscores the impact of the interactions between sharks and pelagic drifting swordfish fisheries in the Mediterranean, which result in increased mortality rates for threatened shark and ray species. Prioritizing conservation measures for endangered elasmobranch populations is crucial for maintaining marine ecosystem balance and ensuring fishery resource sustainability

Ontogenetic vertebral growth patterns in the basking shark Cetorhinus maximus.

Age and growth of the basking shark Cetorhinus maximus (Gunnerus) was examined using vertebral samples from 13 females (261 to 856 cm total length [TL]), 16 males (311 to 840 cm TL) and 11 specimens of unknown sex (376 to 853 cm TL). Vertebral samples were obtained worldwide from museums and institutional and private collections. Examination of multiple vertebrae from along the vertebral column of 10 specimens indica led that vertebral morphology and band pair (alternating opaque and translucent bands) counts changed dramatically along an individual column. Smaller sharks had similar band pair counts along the length of the vertebral column while large sharks had a difference of up to 24 band pairs between the highest and lowest count along the column. Our evidence indicates that band pair deposition may be related to growth and not time in this species and thus the basking shark cannot be directly aged using vertebral band pair counts