(Middle Miocene) of the North Sea Basin
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Cainozoic Research, 5(1-2), pp. 3-12, November2006 The Genus Strioterebrum Sacco, 1891 in the Hemmoorian and Reinbekian (Middle Miocene) of the North Sea Basin Günther Wienrich Vornicker Straße 28, 47574 Goch, Germany: e-mail: [email protected] Received 22 January 2005; revised version accepted 1 August 2006 In the Middle Miocene Hemmoorian and Reinbekian of the North Sea Basin the strata five species belongingto genus Strioterebrum 1861 are found. Three ofthese are new and described ariei Sacco, species to science, as Strioterebrum sp. nov., Strioterebrumfabritzi sp. ronaldi is clear nov., and Strioterebrum sp. nov. There a turnover within the Strioterebrum fauna in the lowermost Reinbekian as three species occurring in the North Sea Basin since the Vierlandianrespectively earliest Hemmooriantimes nearly simultaneously disappear be other Parallels the ofthe Nassarius drawn. For this and to replaced by two species. to development genus Dumeril, 1806, are reason the abundance of the the Strioterebrum is useful tool in the Miocene North Sea Basin most of species, genus a biostratigraphy. KEY:WORDS: Miocene, Hemmoorian,Reinbekian, North Sea Basin, Germany,Netherlands,Gastropods,Strioterebrum,new species, neo- type designation, biostratigraphy. Introduction 20800, H. 12660, surface at unknown altitude. Borehole Lullingen is located at TK25,4403 (Geldem), R: 17010,H. Species of the genus Strioterebrum Sacco, 1861 are a 11000, surface at 28.5 m above sea level. Upper Hem- common faunal constituent of the Miocene of the North moorian and lower Reinbekian (lower Middle Miocene: Sea Basin. Despite their abundance, the genus never re- Giirs & Janssen, 2002) intervals are encountered in these ceived detailed taxonomic attention, and up to now only boreholes.A detailed description ofthe localities is given two species have been accepted. Janse & Janssen (1983) in Wienrich (1997). From these boreholes, 64 samples of and Janssen (1984) were the first authors to recognize the approximately 10 kg sediment were washed (minimum presence of further species, but did not elaborate their sieve mesh 0.1 mm). Specimens of Strioterebrum were ideas. The relationship of the material of these authors, separated and treated taxonomically. The Strioterebrum from material a single locality (Miste near Winterswijk, The Nether- was compared with material from Miste (Gelder- lands) and geological unit (Aalten Member, Miste Bed) land, The Netherlands: material in Naturalis collections, with the new forms is unclear. Strioterebrum material in- Leiden), as well as from Dingden (Nordrhein-Westfalen, vestigated here is derived mainly from two drillings in the Germany) from my own collectionand from the collections Lower Rhine Embayment covering a much larger strati- F. von der Hocht (Kerpen, Germany) and Anton Janse graphic interval in great detail.The material is excellently (Brielle, The Netherlands). Furthermore material from preserved and high numbers of specimens were available, Stemerdink-bridge, Nieuw Wassink (near Stemerdink and provides thebase for a taxonomic review, which is the bridge) and a borehole on the farm Stemerdink all near aim of this paper. Winterswijk (collection Anton Janse) and samples from several boreholes in Schleswig-Holstein, northern Germany (Borchelhof, Heilshoop, Tomesch; coll. Karl Giirs, Kiel, Material and methods Germany) were studied. All specimens are stored in the collectionof the author (to be donatedto the Forschungsin- The material is derived from equivalents ofthe Hoerstgen-, stitut Senckenberg, Frankfurt, Germany), unless stated oth- Dingden- and Bislich beds from the Kevelaer, Wetten and erwise. LUllingen boreholes (Nordrhein-Westfalen, Germany). Borehole Kevelaer is located at TK25, 4403 (Geldem), R: Abbreviations — 16515.8, H. 15951.9, surface at 21.5 m above sea level. Borehole Wetten is located at TK25, 4403 (Geldem), R: GWC Gunther WienrichCollection, Goch, Germany; -4- Figure 1. -5- Figure 1. 1, Strioterebrum (Strioterebrum) basteroti (Nyst, 1845).L-51 7,5,127,2. Lullingen (151 m), x45. Protoconch. 2, Striotere- Protoconch. Striotere- brum (Strioterebrum) ronaldi sp. nov.SMF 327510,(L-39 7,5,127,1), holotype.Lullingen (139 m), x 45. 3, brum ariei Kevelaer 45. (Strioterebrum) sp. nov. SMF327505 (K-90 7,5,127,3), holotype, (90 m), x Protoconch. 4, Strioterebrum (Strioterebrum) hoernesi (Beyrich, 1854).(L-42 7,5,129,1) Lullingen 1 (42 m), x45. Protoconch. 5, Strioterebrum(Strioterebrum) SMF327509 1 45. Massive Strioterebrum fabritzi sp. nov. (L-48 7,5,129,2), paratype. LUllingen (48 m), x protoconch. 6, (Striotere- nov. SMF Kevelaer x45. Small label of Tere- brum)fabritzi sp. 327508,(K-95 7,5,129,2), paratype. (95 m), protoconch.7, Original bra foveolata from the collection ofthe Museum fur Naturkunde, Berlin,apparently notthe handwriting ofBeyrich. 8, Label with the handwriting ofBeyrich from the collection ofthe Bundesamt fur Geowissenschaften, Berlin. 9, Original label of Terebra hoernesi from the collection ofthe Roemer-Pelizaeus Museum, Hildesheim,handwriting of Hermann Roemer. 10, Second label of Terebra hoernesi from the collection ofthe Roemer-Pelizaeus Museum, Hildesheim, author of handwritingunknown. Division NationaalNatuurhis- after several but it is Most RGM Cenozoic Mollusca, whorls, not always present. torisch Museum Naturalis, Leiden, The Nether- specimens lack additional spirals, thus they do not corre- lands; spond with the holotype but with a form which in the litera- SMF Senckenberg Museum und Forschungs Institut, ture often is described as Strioterebrumfoveolata (Beyrich, Frankfurt am Main, Germany. 1854). Below the spiral notch, the holotype ofS. basteroti which has a sculpture of approximately eight spiral riblets, furrows. Above the are separated by very narrow spiral Systematic Palaeontology notch, they are only very weakly pronounced. The base of the bodywhorl, however, is covered with regular spirals. Family Terebridae Adams, 1853 The growth lines have the same orientation as the axial Strioterebrum 1861 ribs. The the end and the Genus Sacco, aperture narrows at apical turns at lower end into the channel, which is retracted. Strioterebrum basteroti (Nyst, 1845) Remarks — This species only appears in the samples as- Figures 1/1, 2/1-4 signed to Hemmoorian and lowest Reinbekian intervals. It is the only species which has been clearly identified so far; 1845 Terebrabasteroti Nyst, p. 582. the definition of a lectotype (Glibert, 1952) makes an un- 1854 Terebra foveolata Beyrich, 118, pi. 6, fig. 15a-b. p. equivocal identification possible. Janssen (1984) recog- 1872 Terebra basteroti Nyst - Koenen, 52, within S. p. (?partim). nized a second morph populations assigned to 1925 Terebra basteroti - 195 (Myurella) Nyst Kautsky, p. basteroti by earlierauthors (Koenen, 1872; Kautsky, 1925; (partim). Anderson, 1964). Strioterehrumfoveolatum Beyrich, 1884, Terebra basteroti - 1952 (Myurella) Nyst Glibert, p. 138, has been synonymized with S. basteroti (e.g., Koenen, pi. 10. fig. 9. 1882; Kautsky, 1925; Anderson, 1964; Janssen, 1984). 1972 Strioterebrum basteroti - (Nyst) Nordsieck, p. 118, Already Beyrich (1854) emphasised the high morphologi- pi. 30, fig. 200 (partim). cal similarity. Dr. Aberhan from the Museum fur 1984 Strioterebrum (Strioterebrum) basteroti (Nyst) - Naturkunde der Humboldt-Universitat in Berlin kindly Janssen, p. 337, pi. 13, fig. 8, pi. 77, figs. 1, 2. made the holotype of Strioterebrum foveolatum (MB.Ga. 1980) available for study. This specimen is in all Distribution— BoreholeKevelaer: common in the lowest details identical to smooth forms ofS. basteroti. Unfortu- samples (Hemmoorian interval); BoreholeLullingen: in the nately, the protoconch ofthe holotype is missing. Also, the lowest samples (lowest Reinbekian interval); Winterswijk- declared location “aus einemBohrlochebei Bocholt” is not Miste, Dingden (Feinsand); BoreholeBorchelhof, (samples very specific. But we can assume that the type specimen between 99-105 m and 108-111 m, Behrendorfian inter- originates from Hemmoorian or lowest Reinbekian inter- val); Borehole Heilshoop HL2 (sample 170 m from Vier- vals, the ofthis in these intervals in landian strata). given presence species boreholes in the region. Description — Variable-shaped species, average height 19 mm. The slightly stocky protoconch consists of four and a Strioterebrum hoernesi (Beyrich, 1854) half to five slightly convex whorls, which are completely 3/4, 4/6-10 first halfwhorl contains fewfaint Figs smooth. Sometimes, the a ribs, especially on the upper half.The protoconch - teleo- 1854 Terebra hörnesi Beyrich, p. 115, pi. 6, figs. 13a, b, conch transitionis not very distinct. The slim, high-turreted 14a, b. teleoconch may possess more than 10 whorls, which are 1872 Terebra hörnesi - 51 Beyrich Koenen, p. (partim). only slightly convex. The surface is glossy. The axial or- 1964 Strioterebrum hoernesi - (Beyrich) Anderson, p. 319, nament consists ofmany strong, slightly ophistocyrth ribs, pi. 45, fig. 277. which are more or less triangular in cross section. The spi- 1983 Strioterebrum (Strioterebrum) hoernesi (Beyrich) - ral consists of notch at about third of the ornament a one Janse & 19. Janssen, p. 137, text fig. 10, pi. 3, fig. height of the whorl and is generally only pronounced be- the notch axial ribs. — tween the Normally, develops only Distribution Borehole Lullingen: common inall samples -6- for the lowermost Reinbekian borehole in condition. except intervals; good Furthermore, as the sizes of the speci- Kevelaer: less more or common,