Distribution and paleoenvironmental framework of middle Miocene marine vertebrates along the western side of the lower Ica Valley (East Pisco Basin, Peru)

Taphonomy of marine vertebrates of the Pisco Formation (Miocene, Peru): Insights into the origin of an outstanding Fossil-Lagerstätte

“…Mysticetes are relatively more abundant in P0, odontocetes more abundant in P1, and pinnipeds are only present in P2. The high percentage of mysticetes in P0 contrasts markedly with their virtual absence in the underlying Chilcatay strata [56,60] and entirely derives from the marginal marine sands at the base of that sequence [35]. Rather than habitat preference, we suggest that this pattern might reflect selective (e.g.…”

“…Starting in 2006, and for some 15 field seasons, our multidisciplinary team focused on establishing a detailed census of the fossil vertebrates cropping out at several fossil-rich exposures of the Pisco Formation. Preliminary results of this long-term research effort included the production of detailed thematic maps displaying the spatial and stratigraphic distribution of hundreds of fossil vertebrates from the key localities of Cerro Colorado, Cerro Los Quesos, and a broad area in the vicinity of Cerro Submarino [17,18,35]. Here, we apply a similar approach to a total of 16 localities (Fig 2), including the aforementioned three, which together involves first-hand observations on 890 vertebrate fossils.…”

“…Specimens from P0 include 2 mysticetes and 1 odontocete from the localities of Dos Cerritos and Cerro Submarino. The most significant (MLP1) consists of a rather eroded partial delphinidan skeleton bearing several incisions on the ribs (Collareta et al [35]: Fig 4C). Most of these traces are short (<1 cm) and represent morphological-genetic types I or II (sensu Cigala Fulgosi [68] and Bianucci et al [69]).…”

“…Although mega-toothed sharks such as Carcharocles megalodon cannot be ruled out, the size and depth of the bite marks are more suggestive of large carcharhinids like Carcharhinus cf. leucas or Galeocerdo aduncus, both of which occur in P0 [35,70].…”

“…More recently, a multidisciplinary team of palaeontologists, stratigraphers, sedimentologists, micropalaeontologists, and mineral scientists conducted a multi-year investigation of the taphonomic processes at play during the deposition of the Pisco Formation. Results from this programme include detailed censuses of key localities [17,18,35], their contextualisation into a comprehensive chronostratigraphic and palaeoenvironmental framework [19,[36][37][38], detailed investigations of exceptionally preserved specimens [25,26,[28][29][30], and preliminary insights into early diagenetic processes [23,24,39,40].…”