Cryptopora lovisati ( Dreger, 1911 )

Dulai, A., 2013, Sporadic Miocene brachiopods in the Naturalis Biodiversity Center (Leiden, the Netherlands): Records from the Mediterranean, the North Sea, and the Atlantic Ocean, Fragmenta Palaeontologica Hungarica 30, pp. 15-51 : 34-37

Cryptopora lovisati ( Dreger, 1911)

( Figs 41–44, 45–58)

Material – Melpignano (1 internal mould); Beugen (4 specimens: 72–73

m: 3; 75–76 m: 1); Winterswijk-Miste (20 specimens); Maasbree (3 specimens),

Beeringen (1 specimen). Size (mm) –

Length 1.8 1.9 2.2 2.7 1.5 1.8 1.6 1.4 2.5 1.9

Width 1.3 1.4 1.8 2.2 1.2 1.4 1.3 1.2 2.1 1.5

Notes – Cryptopora is known since the Early Paleocene and its dozen fossil species were recently summarised by BITNER & CAHUZAC (2004). Cryptopora lovisati was first described from the Miocene of Sardinia by DREGER (1911), but later it was also identified from the Middle Miocene of the Polish Central Paratethys ( POPIEL-BARCZYK & BARCZYK 1990; but not POPIEL-BARCZYK 1980: see at notes of C. nysti ) and from the Middle Miocene sandy deposits of France ( BITNER & CAHUZAC 2004). WIENRICH (1999) mentioned Cryptopora sp. from the Middle Miocene of NW Germany, which later was identified as C. lovisati by BITNER & CAHUZAC (2004). Just recently it was also recognised in the Late Miocene of Italy ( DULAI 2010 a). This is the first record of C. lovisati from the Netherlands, and the several localities suggest that it was a common member of the Miocene brachiopod fauna in the North Sea Basin. Until now, it was probably overlooked because of the small size and the very fragmentary character of the shell.

The only internal mould from Melpignano shows several microbioerosional trace fossils caused by fungi or cyanobacteria (pers. comm. Árpád Dávid) ( Figs 42–44). Microbioerosional traces are common in the Neogene, but generally were described from mollusc shells, not from brachiopods.

The outline of the shell is much more variable than in the case of Italian Late Miocene material ( DULAI 2010 a). The shell shape changes from elongate oval ( Figs 45, 50) to rounded triangular ( Fig. 53) or subcircular ( Figs 46, 48, 52). The beak is high, while the large, deltoidal foramen is hypothyrid. The deltidial plates are disjunct and strongly auriculate: gradually widening, forming a wing-like structure ( Fig. 49). This characteristic modification makes the species easily distinguishable from the other European Miocene species, Cryptopora nysti . On the basis of recent analogies ( CURRY 1983) the wing-like modifications prevent- ed the sinking of the shell’s posterior margin into the soft sandy sediment. The median septum of the dorsal valve is short but very high approximately at the middle of the valve. The mosaic-forming secondary layer fibres are well visible on the inner surface of the shell ( Fig. 51).

The small-sized Cryptopora specimens are supposed to be without traces of drilling predation. It is generally true and most of the specimens are drill-hole free both in the literature and in the studied material of the NBC collection. However, in the case of the Maasbree locality, all of the three available Cryptopora specimens show drill holes (two in dorsal valves and one in ventral valve). Of course, this sample may be not representative because of the very few specimens, but such a high drilling frequency would be a surprise, especially in this small-sized micromorphic species.

Some of the very thin and fragile shells were partly broken during the cleaning process by ultrasonic cleaner, during the SEM photography or removing the samples from the SEM holder ( Figs 47, 52, 54–55).

This is a very widely distributed species, which is known from all European marine Miocene palaeobiogeographic areas: the Mediterranean in Italy (DREGER

1911; DULAI 2010 a; this paper); the Central Paratethys in Poland ( POPIEL-BARCZYK & BARCZYK 1990); the Atlantic Ocean in France ( BITNER & CAHUZAC 2004); the North Sea Basin from Germany ( WIENRICH 1999) and from the Netherlands (DULAI, this paper).