Pliothyrina sowerbyana ( Nyst, 1843 )

Dulai, Alfréd, 2016, Sporadic Pliocene and Pleistocene brachiopods in Naturalis Biodiversity Center (Leiden, the Netherlands): Records from the Mediterranean, and the North Sea Basin, Fragmenta Palaeontologica Hungarica 33, pp. 65-98 : 85-87

Pliothyrina sowerbyana ( Nyst, 1843)

( Figs 35–48)

1843 Terebratula Sowerbyana – NYST, pp. 335–336, Pl. 27, Figs 3 a-b.

1980 Pliothyrina sowerbyana (Nyst) – VAN ROY, pp. 3–7, Pl. 1, Figs 1–7, Pl. 2, Figs 1–7.

1983 Pliothyrina sowerbyana (Nyst) – COOPER, pp. 237–238, Pl. 5, Figs 1–4.

2004 Pliothyrina sowerbyana (Nyst) – VOSKUIL, pp. 50–53, Text-Figs 7A-L.

Material – Gedgrave (3 complete specimens, 50 pedicle and 50 brachial valves); Brightwell (1 brachial valve); Cricqueville-en-Bessin (1 complete specimen, 6 pedicle and 5 brachial valves); Goes (2 pedicle valves and 1 brachial valve, 6 fragments).

Remarks – Large-sized Miocene and Pliocene terebratulids have a long and complex nomenclatural history in the North Sea Basin. Several names were introduced in the literature both in the eastern ( Belgium – the Netherlands) and in the western ( Great Britain) part of the Basin. It seems that nearly all, or at least most of the Oligocene-Pliocene large terebratulids belong to the genus Pliothyrina described by VAN ROY (1980) with type species P. sowerbyana . LACOURT (1983) identified 30 names for Terebratulidae species from the Neogene of the Netherlands (mentioning even some Mesozoic species). Later VOSKUIL (2004) revised LACOURT’s (1983) work, and correctly synonymized nearly all of his terebratulids with P. sowerbyana . The only exception was “ Terebratula ” distinguenda Lacourt, 1984, which was separated with question mark also by VOSKUIL (2004). On the basis of some Dutch private collections (Freddie van Nieulande, Peter Mordijk, Harry Raad) this separate species with very small pedicle opening really exists, and its internal morphology is also significantly different from Pliothyrina , and refers to a separate, new genus. This new taxon hopefully will be described in the near future, in the framework of the cooperation with the above mentioned private collectors.

After VAN ROY’s (1980) description, the name Pliothyrina sowerbyana became widely accepted and well-known, and several papers used this name for large terebratulids in the North Sea Basin (e.g. VOSKUIL 2004; MOERDIJK 2007; RAAD 2004a, b, 2008; VAN NIEULANDE 2009). However, recently MOERDIJK (2016) discussed in detail the nomenclatural problems of Neogene Pliothyrina assemblages of the North Sea Basin. The correct name of the very common and wide-spread form is under discussion, and until the final decision the well-known name P. sowerbyana is used in this paper.

HERMAN in BOSSELAERS et al. (2004) indicated Terebratula ampulla together with P. sowerbyana and Lingula sp. (= Glottidia ) in the Late Miocene of Belgium, illustrated by the dorsal view of a fragmentary specimen (p. 32, Fig. 5c). VAN NIEULANDE (2009) also mentioned P. sowerbyana and Terebratula sp. from the “seashore strands”. However, until now, the presence of Terebratula or specifically T. ampulla has not been confirmed in the North Sea Basin; it is a typical Mediterranean taxon.

Pliothyrina ? sp.

Material – Gedgrave (177 fragments); Goes (1 fragment).

Remarks – The Coralline Crag samples from Gedgrave contain several small-sized, unidentifiable smooth Terebratulidae fragments. As Pliothyrina sowerbyana specimens are common in these beds, these fragments are regarded as Pliothyrina sp. with question mark.