Involutina hungarica (Sidó, 1952) from the Albian Tethys: Architecture, palaeoenviroment and palaeobiogeography

• Architecture of Involutina hungarica (ex- Hensonina lenticularis), Iberian Peninsula.
• I. hungarica lived in shallow-water environments crawling on firm substrates.
• The age of I. hungarica is Albian.
• The taxon is present in carbonate deposits from Portugal to Iran.

The re-study of the so-called “Hensonina lenticularis” Moullade and Peybernés, 1973, a non-valid genus synonymous of Involutina hungarica (Sidó) from several localities of the Iberian Peninsula allowed us to precise some new data on the architecture, palaeoenvironment, palaeocology, age and palaeobiogeography of this Cretaceous involutinid. Specimens exhibit a lamellar-perforate wall texture with large caliber pores, which are distributed between the protuberant pustules. In the umbilical areas, between two consecutive chamber walls, the strongly ornamented lamellar thickenings constrain the restricted cameral space. Involutina hungarica lacks supplemental skeleton. The Cretaceous taxon lived probably crawling on the firm substrates in shallow-water environments as some recent involutines, which do not agree with the deeper environment suggested for the Triassic and Early Jurassic relatives. In all of the studied localities the associated fauna suggests an Albian age for I. hungarica. The discovery of such taxon in deposits in Iran (Zagros Mountains and Khorasan province) reveals a wider geographic distribution than has been previously accepted.