Filogranula cincta (GOLDFUSS, 1831)

Kočí, Tomáš & Jäger, Manfred, 2015, Filogranula Cincta (G, 1831), A Serpulid Worm (Polychaeta, Sedentaria, Serpulidae) From The Bohemian Cretaceous Basin, Acta Musei Nationalis Pragae Series B 71 (3 - 4), pp. 293-300 : 294-296

Filogranula cincta (GOLDFUSS, 1831)

Text-fig. 2, Text-fig. 3 , Pl. 1, Fig. 1–5

1831 Serpula cincta nobis – Goldfuss, p. 237, pl. 70, fig. 9a–c.

1837 Vermilia cristata, DUJ. – Dujardin, p. 233, pl. 17, fig. 17.

1840 Serpula undulata nob. – von Hagenow, p. 668.

1845 Serpula cristata DUJARDIN – Reuss, p. 18, pl. 13, fig. 92a–c.

1846 Serpula fluctuata SOW. – Reuss, p. 106, pl. 24, fig. 10a–b.

1869 Serpula fluctuata, SOW. – Frič, p. 220.

1869 Serpula cristata, DUJ. – Frič, p. 221.

1870 Serpula fluctuata, SOW. – Frič, p. 197.

1870 Serpula cristata, DUJ. – Frič, p. 198.

non 1875 Serpula cincta GOLDF. – Geinitz, p. 286, pl. 63, fig. 18a–c.

1913 Serpula pentastemma nov. nom. – Wegner, p. 200, text-fig. 12.

1961 Flucticularia flucticularia n. sp. – Regenhardt, p. 57, pl. 9, fig. 2.

1961 Flucticularia undulata ( HAGENOW, 1840) – Regenhardt, p. 57, pl. 6, fig. 6.

1961 Flucticularia trilix n. sp. – Regenhardt, p. 58, pl. 5, fig. 5.

1961 Flucticularia calamistrata n. sp. – Regenhardt, p. 59, pl. 6, fig. 5.

1961 Vepreculina plumosa n. sp. – Regenhardt, p. 68, pl. 6, fig. 4.

1979 Filogranula fluctuata ( SOWERBY 1829) – Lommerzheim, p. 155.

1983 Filogranula cincta (GOLDFUSS, 1831) – Jäger, pp. 68–71, pl. 8, figs 8–13.[with a long synonymy list]

1987 Filogranula cincta (GOLDFUSS, 1831) – Jäger, p. 39, pl. 1, figs 11–16.

1991 Filogranula cincta (GOLDFUSS 1831) – Jäger, pp. 148–149, pl. 5, figs 1–5.

1996 Filogranula cincta (GOLDFUSS, 1831) – Radwańska, p. 71, pl. 8, figs 1–6.

2005 Filogranula cincta (GOLDFUSS, 1831) – Jäger, p. 151, pl. 2, figs 10–13.

2007 Filogranula cincta (GOLDFUSS) – Kočí, pp. 112–113, figs 1–2.

2011 Filogranula cincta (GOLDFUSS, 1831) – Jäger, p. 686, pl. 4, fig. 1.

2012 Filogranula cincta (GOLDFUSS) – Kočí, p. 122, fig. 1F.

2012 Filogranula cincta (GOLDFUSS, 1831) – Jäger, p. 51, pl. 1, figs 13–14.

2014 Filogranula cincta (GOLDFUSS, 1831) – Ippolitov et al., p. 142, fig. 8C–D.

S t r a t i g r a p h i c a l r a n g e. Early Hauterivian to

Late Maastrichtian.

M a t e r i a l. Two near-complete specimens from locality Velim-Skalka are deposited in the National Museum Prague (NM-O6396 and NM-O6397). From the same locality, forty-one incomplete specimens and tube remains were studied. One near-complete specimen is from Předboj (NM-O7549), another complete specimen is from Plaňany. Seven specimens (two of them free and five attached to sponges; NM-O7619 – NM-O7621) are from the locality Chrtníky, layer 8a/b after Žítt et al. (2006), and three from the same locality, layer 8f. One small fragment comes from the large boulder at Karlov (see Žítt and Nekvasilová 1989). One specimen (NM-O7612), attached to a sculptured core of a gastropod, is from the locality Klokočské Loučky.

D e s c r i p t i o n. The tube consists of an attached posterior portion and often, depending on individual age and ecological conditions, a short or long free anterior portion. The attached portion may be straight, curved, irregularly serpentine, or may form a loop, whereas the free portion is straight or slightly curved. The tube increases in diameter only gradually and may reach a few centimetres in total length, although mostly only fragments are found. The two near-complete specimens from Velim-Skalka are 6.7 and 7 mm long, respectively, and the longest specimen from Chrtníky is 19.5 mm long. The anterior free portion which is 2.9 mm and 3 mm long in the two complete specimens, respectively, ascends obliquely upward; it rises at angles of 30°, 43°, 60° and 86° in four specimens. The cross-sections of broken tubes, mostly from the attached posterior tube portions, range from 0.9 to 2.3 mm in diameter, respectively from 1.8 to 2.8 mm if measured at the base of the trapezoidal cross-section. Outside the Bohemian Cretaceous Basin, the largest specimens may reach up to 3 mm in diameter ( Jäger 1983). In several tubes which possess a peristome at the transition from the attached to the free portion, the free portion has a somewhat smaller diameter compared to the anterior part of the attached portion. The tube diameter at the aperture ranges from 1.2 to 1.9 mm.

On the upper side of the attached portion, the tube bears three longitudinal keels of which especially the two upper/lateral keels are usually strongly developed as more or less undulating, cockscomb-like ridges and/or bear tiny protruding spines. At the transition from the attached to the free portion, the two basal-lateral edges turn into two additional keels which may be sharp but small and straight or may be similar in shape to the other three keels. At each of the two latera, there is often a longitudinal furrow situated at half to three quarters of the height of the latera. Pentagonal stellate peristomes may occur, especially at or near the transition from the attached to the free portion, but also elsewhere, but most of them are relatively weak to moderately developed in the specimens from the Bohemian Cretaceous Basin when compared to some finds from other regions. Under the microscope, delicate transverse striation is visible. The striation, incremental lines and peristomes may be straight, but more often they are somewhat curved and protrude at the keels and at the edges of the tube’s base.

The cross-section of the tube is most often trapezoidal but may also be quadrangular or pentagonal in the attached tube portion, whereas it is quadrangular or pentagonal in the free portion. A pentagonal cross-section is developed mainly at the peristome level and in the free portion of large specimens. The tube wall is moderately thick, but may be very thick near the peristomes. Neither tubulae nor tabulae are visible. The lumen is circular.

A small fragment from Chrtníky, layer 8f, which has only weakly developed keels but strongly developed transverse striation, is infested by the symbiont hydroid Protulophila gestroi ROVERETO, 1901 .

R e m a r k s a n d r e l a t i o n s h i p s. In the Late Cretaceous, three species have tube morphologies relatively similar to Filogranula cincta : Vermiliopsis fluctuata (J. DE C. SOWERBY, 1829) , Metavermilia (Vepreculina) fimbriata REGENHARDT, 1961 and Serpula ? trilineata ROEMER, 1841. Vermiliopsis fluctuata is distinguished by possessing two additional longitudinal ornamental elements (altogether five keels plus two basal edges in the attached portion and seven keels in the free portion), by its heptagonal cross-section and by its flaring peristomes which protrude obliquely at the latera. In Serpula ? trilineata the longitudinal keels are more weakly developed, and peristomes are absent, but there is delicate transverse ornamentation consisting of very small wrinkles. Moreover, the aperture does not ascend upwards, and there is no free tube portion known. Metavermilia (Vepreculina) fimbriata remains much smaller (tube diameter only 0.7–1 mm), only the free tube portion is known, and four to eight (usually five or seven) delicate longitudinal keels are situated all around the tube, whereas the lateral areas of Filogranula cincta tubes bear no keel.

The recent species Crucigera websteri BENEDICT, 1887 has three irregularly undulating longitudinal keels that may reach 1.4 mm in height; the width of the tube may reach 5.5 mm including the keels. In juvenile specimens the base of the keels may be perforated. Sometimes there is a pair of faintly developed longitudinal ridges near the base of the tube. Terminal flaring peristomes or collar-like rings have not been observed (ten Hove and Jansen-Jacobs 1984).

P h y l o g e n y. Species similar to Filogranula cincta in tube morphology were already common in the Jurassic: “ F. ” tricristata (GOLDFUSS, 1831) in the Late Toarcian and Early Aalenian of Germany and France ( Jäger 1983, p. 68; Ippolitov et al. 2014, p. 146), and “ F. ” runcinata (J. DE C. SOWERBY, 1829) in the Kimmeridgian of Great Britain and in the Callovian and Oxfordian of Russia, Poland and Germany and even mass-occurrences in the Oxfordian of Russia ( Ippolitov 2007, pp. 263–264, pl. 7, figs 7–12; Ippolitov et al. 2014, p. 146, fig. 7K). However, the tubes occurring in the Oxfordian (“Malm alpha”) of southern Germany, mentioned by Jäger (1983, p. 69), may represent a different species or even a different genus. However, the problem exists that Recent and presumably also Late Cretaceous tubes of Filogranula sensu stricto belong to

Clade BI ( Ippolitov et al. 2014, fig. 1 including Recent genera closely related to Filogranula sensu stricto, and fig. 8C–D), whereas at least the well preserved tubes of “ F. ” runcinata from the Oxfordian of Russia are transparent and therefore should be related to the transparent tubes of Recent representatives of the genus Placostegus which belong to

Clade AII ( Ippolitov et al. 2014, p. 146, fig. 7K). In other words, it may be possible that the Jurassic and the Cretaceous to Recent tubes, in spite of similar shape and ornamentation, belong to different clades.

Relatively little is known of the genus’ occurrence in the Early Cretaceous: F. cincta from the Early Cretaceous is mentioned by Ippolitov (2007, p. 263), and a few specimens of F. cincta are known from the Early Hauterivian of northern Germany (Jäger, personal observation) and one specimen from the Barrêmian of southeast France, where a second species presumably belonging to Filogranula is common at the same site ( Jäger 2011, pp. 686–690). Ware (1975) introduced a new species, Flucticularia sharpei , from the Aptian of southern England and mentioned additional specimens presumably belonging to the same species from the Albian of southern England; these Aptian and Albian tubes are very similar to F. cincta and may belong to this species.

In the Late Cretaceous, the genus Filogranula is again common, with the species F. cincta being widespread in different facies, from the earliest Cenomanian ( Lommerzheim 1979, p. 155, described as Filogranula fluctuata ( SOWERBY, 1829)) until latest Maastrichtian (up to only 0.7 – 1.2 m below the Cretaceous/Palaeogene boundary at the locality Rødvig / Stevns Klint, Denmark; Jäger 2005, p. 151).

Very little is known about Filogranula in the Cenozoic. Ippolitov (2007, p. 263) listed Serpentula alata BRÜNNICH NIELSEN, 1931 from the Danian of Denmark as a species of the genus Filogranula ; however, Jäger (1993), when studying serpulids from the Danian of the Netherlands and Belgium, described this species as Placostegus alatus .

In the seas of today, several living species of this genus are known (ten Hove and Kupriyanova 2009). In older literature, they are usually described under Omphalopoma MØRCH, 1863 , until Zibrowius (1972) recognized Omphalopoma to be a nomen dubium and replaced it with the junior but valid genus name Filogranula LANGERHANS, 1884 (see, for example, Southward 1963, Zibrowius 1968, 1972, ten Hove and Kupriyanova 2009). In the Late Cretaceous and especially in the Recent species, peristomes, especially in the free tube portion, are more common, more strongly developed and morphologically more diverse, compared to the Jurassic representatives.

P a l a e o e c o l o g y a n d e c o l o g y. Jurassic Filogranula specimens are often found in condensed layers of sediment (Jäger, personal observations in the Late Toarcian; Ippolitov 2007, p. 260). Similarly, Early Cretaceous specimens are found in shallow marine deposits ( Jäger 2011). However, in the Late Cretaceous, the species Filogranula cincta is euryecologic and common in many different fully marine facies ( Jäger 1983, p. 71, 2011, p. 686). Lommerzheim (1979, p. 156) assumed that this species (as Filogranula fluctuata ) lived from the littoral down to a depth of circa 200 m where it was attached to various substrates (shells, remains of corals and rock fragments). It seems strange that within the BCB, Filogranula cincta , in spite of its occurrence in at least eight different localities in the Czech portion of this basin, had not been detected yet, apart from the uncertain mention by Wegner (1913), in the Saxon portion of this basin, as the three-keeled tubes determined as “ Serpula cincta ” by Geinitz (1875) belong to different genera ( Jäger 1983, 2014). Although being euryecologic during all of the Late Cretaceous, it seems that the main occurrence of Filogranula cincta may have slowly shifted from the littoral / shallow water realm to the offshore chalk facies during the Cenomanian until Coniacian times, because at least from the Coniacian onwards, this species is more common and widespread in offshore chalk facies than in nearshore shallow water facies ( Jäger 1983, p. 71, and subsequent observations). Individuals of the extant species of the genus Filogranula live at depths of 15–1780 m ( Zibrowius 1968, Southward 1963). In the Mediterranean Sea, they inhabit the deep sea as well as submarine caves in relatively shallow water ( Zibrowius 1968). The extant species Filogranula annulata (O. G. COSTA, 1861) is widespread throughout the Mediterranean in submarine caves as well as in “coralligenous” biota, from shallow water down to a depth of 100 m, and is found frequently together with the Red Coral ( Zibrowius 1981).

Figures

Text-fig. 3. Filogranula cincta (GOLDFUSS), locality Chrtníky (Early Turonian), no. NM-O7620, a – general view of two specimens attached to a lychniscosan sponge Diplodictyon heteromorphum. Length of the sponge is 60 mm. b – detail of the tubes. Length of the left tube is 5.4 mm. The diameter of the aperture is 1.2 mm. Length of the right tube is 6 mm without the looped posterior portion. The diameter of the aperture is 1.4 mm. Scale bars are 5 mm.