ZENASPIS PODOLICA HEAD SHIELD

A Devonian bony fish mortality plate showing a lower shield of Zenaspis podolica (Lankester, 1869) from Lower Devonian deposits of Podolia, Ukraine.

Podolia or Podilia is a historic region in Eastern Europe, located in the west-central and south-western parts of Ukraine, in northeastern Moldova. Podolia is the only region in Ukraine where 420 million-year-old remains of ichthyofauna can be found near the surface, making them accessible to collection and study. Zenaspis is an extinct genus of jawless fish which thrived during the early Devonian. Being jawless, Zenaspis was probably a bottom feeder, snicking on debris from the seafloor similar to how flounder, groupers, bass and other bottom-feeding fish make a living.

For the past 150 years, vertebrate fossils have been found in more than 90 localities situated in outcrops along banks of the Dniester River and its northern tributaries, and in sandstone quarries. At present, the faunal list of Early Devonian agnathans and fishes from Podolia number seventy-two species, including 8 Thelodonti, 39 Heterostraci, 19 Osteostraci, 4 Placodermi, 1 Acanthodii, and 1 Holocephali (Voichyshyn 2001a).

In Podolia, Lower Devonian redbeds strata (the Old Red Formation or Dniester Series) are up to 1800 m thick and range from Lochkovian to Eifelian in age (Narbutas 1984; Drygant 2000, 2003).

In their lower part (Ustechko and Khmeleva members of the Dniester Series) they consist of lovely multicoloured, mainly red, fine-grained cross-bedded massive quartz sandstones and siltstones with seams of argillites (Drygant 2000).

We see fossils of Zenaspis in the early Devonian of Western Europe. Both Zenaspis pagei and Zenaspis poweri can be found up to 25 centimetres long in Devonian outcrops of Scotland.

Reference: Voichyshyn, V. 2006. New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine. Acta Palaeontologica Polonica 51 (1): 131–142. Photo care of the awesome Fossilero Fisherman.