THE TENTACULITID AFFINITIES OF ANTICALYPTRAEA FROM THE SILURIAN OF BALTOSCANDIA

Abstract

The problematic fossil Anticalyptraea Quenstedt, 1867, traditionally interpreted as a phorid gastropod, is here assigned to the Class Tentaculita. Its dextrally coiled substrate-cemented tube, bulbous initial chamber, vesicular tube wall and pseudopunctate microlamellar shell structure closely resembles Trypanopora (Tentaculita), but Anticalyptraea differs in having the cones of the pseudopunctae orientated in the opposite direction. Pseudopunctae orientated similarly to Anticalyptraea occur in Cornulites and thick-walled tentaculitids. Anticalyptraea differs from gastropods in having pseudopunctae and a vesicular shell structure.

Calcareous tubeworms of the Phanerozoic

“…The diversity of Palaeozoic problematic tubeworms was highest in the Silurian and Devonian (Bouček 1964;Richards 1974;Larsson 1979;Vinn 2004Vinn , 2005aVinn , 2006aTaylor & Wilson 2008;Vinn & Mõtus 2008) and decreased markedly in the Carboniferous. Hitherto reported shell repair indicates attempted predation on the problematic tubeworms in the Late Ordovician (Vinn 2009a), Silurian (Larsson 1979;Vinn & Mutvei 2005;Vinn & Isakar 2007;Vinn 2009a), and Devonian (Wilson & Taylor 2006). Thus, predation pressure may have had some role in shaping the evolution of Palaeozoic problematic tubeworms.…”

“…in Ordovician to Jurassic microconchids, and Jurassic to Recent serpulids (Serpulidae, Spirorbidae) (Taylor & Vinn 2006); (4) substrate-cemented, spiral, erect, conical shells, e.g. in Silurian to Devonian Anticalyptraea (Vinn & Isakar 2007), and Cretaceous Orthoconorca (Jäger 1983); (5) pseudocolonial branching tubes, e.g. in Silurian to Permian hederelloids (Taylor & Wilson 2008) and Triassic to Recent filogranids (Serpulidae) (Senowbari-Daryan & Link 2005; ten Hove & Kupriyanova 2009).…”

“…They share affinities with tentaculitids (Weedon 1991(Weedon , 1994) and more generally with lophophorates (Taylor & Vinn 2006). The other common Palaeozoic tubewormlike calcitic problematica (tentaculitids, cornulitids, and trypanoporids) have often been affiliated with annelids, but are more recently transferred to lophophorates (Weedon 1990(Weedon , 1991(Weedon , 1994Vinn & Mutvei 2005;Vinn 2005aVinn , 2006bVinn & Isakar 2007;Vinn & Mõtus 2008). Some tubeworm-like Early Palaeozoic phosphatic fossils such as Sphenothallus (van Iten et al 1992) and the related hyolithelminth Torellella (Vinn 2006c) have been interpreted as cnidarians on the basis of their tube structure.…”

“…However, some of the Early Palaeozoic questionable polychaete worm borings in brachiopod shells could have been made by phoronids (Vinn 2005b). Enigmatic Palaeozoic tubicolous biomineralized tubeworms such as cornulitids (Vinn & Mutvei 2005;Vinn 2005a;Vinn & Mõtus 2008), microconchids (Taylor & Vinn 2006;Vinn 2006a, Vinn & Taylor 2007, Tymbochoos (Vinn 2006b), Anticalyptraea (Vinn & Isakar 2007), and tubicolous colonial hederelloids (Taylor & Wilson 2008), could represent calcifying phoronids or phoronid-related lophophorate worms.…”

First fossil record of parasitism in Devonian calcareous sponges (stromatoporoids)

“…Trypanoporids have recently been considered as relatives of tentaculitids (Weedon, 1991), which form the separate class Tentaculita (probably allied to lophophorans; Vinn and Isakar, 2007).…”