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The regular echinoidPlacentinechinus davoliigen. et sp. nov. is described from eight Early Pleistocene (Gelasian–Calabrian) sites in north and south Italy. It is the most recent record known for the family Temnopleuridae in the European domain and the first in the Mediterranean area. A review of temnopleurid palaeobiogeography, and morphological comparisons, suggest thatP. davoliiwas derived from a marsupiate brooder that lived in the north-east Atlantic during Messinian–middle Gelasian time. This indicates a brooding reproductive strategy forP. davolii, although it does not bear any evidence of a marsupium. The stratigraphy and climatic setting inferred for the study sites indicate thatPlacentinechinusrepresents a significant southward shift of the European Temnopleuridae, triggered by a progressive cooling that changed the Mediterranean climate from tropical to subtropical-temperate. A further climatic deterioration, perhaps that at about 0.8 Ma with the onset of the 100 kyr-controlled Ice Ages, caused its extinction. The palaeoecology ofPlacentinechinus, as deduced from palaeoenvironmental reconstructions of the study sites, indicates that it lived in shoreface to shallow offshore, moderately agitated waters, often together with the scallop-polychaeteAequipecten-Ditrupaassociation. It tolerated more or less marked conditions of turbidity, but flourished in trophically well-structured palaeocommunities. The main morphological characters distinguishingPlacentinechinusare the very depressed test and the extremely large apical opening, up to 82% of the test diameter, which is so far the largest known for an adult echinacean echinoid. The statistically exhaustive morphometric data collected from more than 100Placentinechinustests indicate that inferring sexual dimorphism for Temnopleuridea echinoids based only on the apical disc width could be misleading. ForP. davolii, both climate and environmental stability, in terms of sedimentation rate and nutrient supply, may have been concurrent drivers of its evolutionary history. http://zoobank.org/urn:lsid:zoobank.org:pub:EBB96C8C-943D-4253-82FE-09B9132591E7 [ABSTRACT FROM AUTHOR]

New material from the Miocene of Italy allows revision of the spatangoid genus Mariania Airaghi, 1901 and proposal of an emended diagnosis. Particularly characteristic, previously overlooked features of the genus include the presence of well-developed phyllodes made up from short, almost equidimensional plates in oral ambulacra II, III and IV. Unlike in other Spatangoidea, where the adoral plates rapidly become elongated towards the margin, they stay short in Mariania and are not constricted halfway between the peristome and the margin. In addition, most species of Mariania possess a characteristic domal profile with steep sides and lack a raised keel in aboral interambulacrum 5. Their petals are wide, open distally and extend almost to the margin. The plastron is not indented behind the episternal plates and the labral plate extends to the second ambulacral plates. Fascioles are missing in all specimens examined. The combination of these morphological features enable the separation of Mariania from the genera Macropneustes, Hypsopatagus and Spatangus, to which members of the genus have been assigned by previous authors. Cladistic analysis carried out to unravel the uncertain systematic position of Mariania failed tofind well-supported relationships, but firmly places Mariania within the Brissidina. Most previous family attributions could be, however, ruled out. Based on the available data a placement within Spatangoidea seems most likely, where it takes up an intermediate position between maretiids, loveniids and spatangids. Three different species are identified within the studied sample: Mariania marmorae, the type species of the genus; M. stefaninii sp. nov. from the late Burdigalian-early Langhian of northern Italy; M. comaschicariae sp. nov. from the Burdigalian of Sardinia. These new species are distinguished from M. marmorae by their lower tests, shorter labral plates and shorter petals. Mariania comaschicariae sp. nov. differs from M. stefaninii sp. nov. by its lower test, more anterior apical disc and less numerous plates in the oral anterior paired ambulacra. Test morphology and parent rock sedimentology suggest that Mariania was an epifaunal echinoid, which lived in inner shelf environments, characterized by soft bottoms and a tropical climate. [ABSTRACT FROM AUTHOR]

Abstract Prospatangus thieryi Lambert, 1909 (Echinoidea, Spatangoida) is an echinoid from the Early Miocene of Sardinia, Italy. The original description, mainly based on subjective morphological observations (e.g. from Lambert, 1909: "une forme un peu plus longue que large, à sillon peu profond, apex légèrement excentrique en avant"), made it problematic the comparison with other similar taxa. New observations based on a large set of structural and morphometric data taken from the lectotype and a newly collected specimen, both from Cameseda (Ales, Oristano Province, Sardinia, Italy), one of the two localities indicated by Lambert (1909) in the type area, enabled to improve the definition of this species and to transfer it into a new genus, Sardospatangus nov. gen. It differs from Spatangus Gray, 1825 (junior synonym: Prospatangus Lambert, 1902) mainly by the labrum, which is more elongate and in contact with two plates on either side of the adjacent ambulacra (I and V) instead of one, and by a lower total number of plates in the ambulacrum III. Two additional species of Sardospatangus nov. gen are identified within a large number of specimens from the Miocene of Sardinia examined in public institutions: S. caschilii nov. sp., proposed as the type species of the new genus, and S. arburensis nov. sp. [ABSTRACT FROM AUTHOR]