Page 1 - A_new_subtropical_temperate-Borghi2016
P. 1
Journal of Systematic Palaeontology, 2016
http://dx.doi.org/10.1080/14772019.2016.1184191
Downloaded by [vittorio garilli] at 22:43 08 June 2016 A new subtropical-temperate brooding echinoid with no marsupium: the ï¬rst
Mediterranean and the last European Temnopleuridae from the Early
Pleistocene of Italy
Enrico Borghia and Vittorio Garilli b*
aSocieta Reggiana di Scienze Naturali, Via Tosti 1, I-42100 Reggio Emilia, Italy; bAPEMA-Paleosoï¬a,
Research and Educational Service, Via Alla Falconara 34, I-90136 Palermo, Italy
(Received 24 November 2015; accepted 25 February 2016)
The regular echinoid Placentinechinus davolii gen. et sp. nov. is described from eight Early Pleistocene
(GelasianÀCalabrian) sites in north and south Italy. It is the most recent record known for the family Temnopleuridae in
the European domain and the ï¬rst in the Mediterranean area. A review of temnopleurid palaeobiogeography, and
morphological comparisons, suggest that P. davolii was derived from a marsupiate brooder that lived in the north-east
Atlantic during MessinianÀmiddle Gelasian time. This indicates a brooding reproductive strategy for P. davolii, although
it does not bear any evidence of a marsupium. The stratigraphy and climatic setting inferred for the study sites indicate that
Placentinechinus represents a signiï¬cant 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 of
Placentinechinus, 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-polychaete Aequipecten-Ditrupa
association. It tolerated more or less marked conditions of turbidity, but flourished in trophically well-structured
palaeocommunities. The main morphological characters distinguishing Placentinechinus are 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 100 Placentinechinus tests
indicate that inferring sexual dimorphism for Temnopleuridea echinoids based only on the apical disc width could be
misleading. For P. 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
Keywords: Echinoidea; Temnopleuridae; brooding; Mediterranean; Early Pleistocene; palaeoclimate
Introduction examples of change within echinoid assemblages from the
Atlanto-Mediterranean Neogene may be traced in the dis-
The intricate climatic evolution that followed the late appearance of the sand dollar Amphiope Agassiz, 1840 in
Miocene palaeogeographical change associated with the early Messinian (Stara & Borghi 2014), and of the
Mediterranean desiccation (Ruggieri 1967; Hsu€ et al. genera Clypeaster Lamarck, 1801, Hypsoclypus Pomel,
1973) led to signiï¬cant shifts in the faunal assemblages of 1869 and Echinoneus Leske, 1778 in the Gelasian
the Atlanto-Mediterranean domain (e.g. Malatesta & Zar- (Neraudeau et al. 2001). As shown here, a few shallow-
lenga 1986; Loubere & Moss 1986; Cronin et al. 1993; water taxa, such as Echinolampas Gray, 1825 and Schize-
Head 1998; Cronin et al. 1999; Monegatti & Rafï¬ 2001; chinus Pomel, 1869, disappeared in the early Calabrian.
Taviani 2002; Wood 2009; Garilli 2011; Vertino et al. The main changes in the deeper-water assemblages
2014). Compared to other groups, there are little data con- include the disappearance of Histocidaris Mortensen,
cerning the NeogeneÀQuaternary faunal change within 1903, Stirechinus Desor, 1856 and Cidaris margaritifera
echinoids (Roman & Soudet 1990; Neraudeau et al. 2001; Meneghini, 1862, whose last Mediterranean record dates
Kroh 2007; Borghi et al. 2014), which are one of the most back to the early Calabrian of Sicily (Borghi et al. 2014).
successful marine groups due to their various reproductive All these genera, or their closely related living taxa, today
strategies (Gillespie & McClintock 2007). Signiï¬cant inhabit warm temperate/tropical areas.
*Corresponding author. Email: vittoriogarilli@apema.eu
Ó The Trustees of the Natural History Museum, London 2016. All Rights Reserved.
