Serpulidae, Rafinesque, 1815

Serpulidae View in CoL sp. 1

Fig. 12A, B View Fig .

Material.— 71 specimens attached to bivalve shells (and moulds to a lesser extent), and oncoids from the upper Bajocian–lower Bathonian (Middle Jurassic) of Ogrodzieniec-Świertowiec (23), upper Bathonian–lower Callovian Middle Jurassic ) of Bolęcin (5), and Callovian (Middle Jurassic) of Zalas (43), Polish Jura (see Table 1); GIUS 8-3589 , GIUS 8-3745 , GIUS 8-3750 .

Description.—Tubes small to medium-sized (up to 100 mm long). Tubes are morphologically diverse, ranging from almost straight, gently curved to more strongly coiled. Tube diameter (slightly exceeding 1 mm) almost constant in the adult part. Depending on the specimen, tubes may be either smooth without any ornamentation, except for well-developed, irregularly scattered ampullacea-type to slightly nodular peristomes, or bear some corrugations and/or striae on the tube’s outer surface. On the upper side of some of the tubes a faint, crest-like keel present, as well as two longitudinal, lateral edges on the marginal parts of the tube. The tube attached to the substrate by its entire length with minor flanges. The tube base seems to be even narrowed below the lateral margins which are directed outwards. All the specimens are distinctly flattened which results in the rounded-rectangular, or at least angular, to subcircular cross-section.

Remarks.—The general shape of the tubes (irregularly curved, of nearly constant diameter and substantial length, bearing ampullacea-type to slightly nodular peristomes and longitudinal ornamentation) is similar to the Pseudovermilia sp. described above. The difference is the intensity of the reticulate ornamentation, which is very prominent in Pseudovermilia sp. , whereas in the Serpulidae sp. 1 it is less pronounced, or even occasionally lacking in some parts of the tubes. The reticulate ornamentation of Recent tubes of Pseudovermilia may be very variable, but remains strong ( Hove 1975), which rather excludes our specimens from this genus. Alternatively, at least a part of the tubes may represent a species of either Filogranula or Nogrobs with relatively well-developed transverse ornamentation.

Serpulidae sp. 2

Fig. 13A View Fig .

Material.—One unattached and partially eroded specimen from the middle Bathonian (Middle Jurassic) of Gnaszyn Dolny, Polish Jura (see Table 1); GIUS 8-3730.

Description.—The tube is thick and robust, 7 mm in diameter, less than 16 mm long, consisting of a small attached and a short free tube portion. bearing irregular but prominent ampullacea-type peristomes. The specimen bearing some well-visible, perpendicular growth lines. Cross-section circular, wall composed of two layers.

Remarks.—The specimen shows some superficial resemblance to Neovermilia ampullacea (Sowerby, 1829) ( Jäger 1983: 41, pl. 5: 3, as “ Proliserpula ampullacea ”) due to distinctive, thick, bulge-like ampullacea-type peristomes and circular cross-section.