Fusiteuthis polonica Kongiel, 1962

Christensen, Walter Kegel, 2002, Fusiteuthis polonica, a rare and unusual belemnite from the Maastrichtian, Acta Palaeontologica Polonica 47 (4), pp. 679-683 : 679-680

Fusiteuthis polonica Kongiel, 1962

Fig. 2 .

Fusiteuthis polonica ; Kongiel 1962: 28, pl. 1: 1–3.

Fusiteuthis polonica ; Kongiel−Christensen 1997: 76, pl. 2: figs. 6, 7.

Type: The holotype, by original designation, is the original of Kongiel (1962: pl. 1: 1–3), from the upper Upper Maastrichtian , Bochotnica quarry near Kazimierz Dolny in the Vistula Valley, central Poland. It is housedintheMuseumoftheEarth(MuzeumZiemi)inWarsaw, Poland andregisteredasMZVIIIMcd162.Measurementsofcriticalcharacters of the holotype are shown in Table 1. It is re−figured here as Fig. 2A .

Material.— One specimen, MGUH 26406 ( Fig. 2B ), from the basal Maastrichtian, uppermost part of the Belemnella lanceolata Zone , “Saturn” chalk pit at Kronsmoor, northwest Germany. It came from ca. 3.5 m below marker horizon G 610, which is a pyrite−impregnated bed, that is ca. 9.5 m above the base of the Maastrichtian and ca. 0.5 m below the top of the Belemnella lanceolata Zone ( Fig. 3 ). It was collected by the late Dr. M.−G. Schulz.

Description.—Measurements of the critical characters are shown in Table 1. Guard ca. 51 mm, slender and lanceolate in ventral and lateral views; maximum lateral diameter is situated in the middle part of guard; alveolus shallow; crosssection of anterior end oval, with dorsoventral diameter slightly larger than lateral diameter; ventral fissure short; guard slightly prolonged ventrally around the ventral fissure; apical end acute; guard smooth; interior characters are not known, because the fragile anterior end precludes the guard to be split in the median plane to reveal them.

Discussion.— MGUH 26406 is smaller than the holotype and is therefore considered to be an adolescent specimen. It has a relatively deeper alveolus than the holotype, but this may be related to the fact that the anterior end of the guard is better preserved. The Slenderness Quotient ( SQ), which is the length of the guard divided by the dorsoventral diameter at the alveolar end, of the holotype ( SQ = ca. 21) is about twice the value of that of MGUH 26406 ( SQ = 10), whereas the ratio of the length of the guard divided by the maximum lateral diameter is very closely similar in the two specimens.

Figures

Fig. 2. Fusiteuthis polonica Kongiel, 1962. A. Holotype MZ VIII Med 162 in dorsal (A1), lateral (A2), ventral (A3) views, and view of the ventral anterior end of the guard, showing the ventral fissure (A4), approximately × 5. B. MGUH 26406, “Saturn” chalk pit at Kronsmoor, uppermost part of the Belemnella lanceolata Zone, ca. 3.5 m below marker horizon G 610 in dorsal (B1), lateral (B2), ventral (B3) views, and view of the ventral anterior end of the guard, showing the ventral fissure (B4), × 4. MGUH 26406 is registered in the Type Collection of the GeologicalMuseum,UniversityofCopenhagen.Allfiguresarecoatedwith ammonium chloride and are natural size unless otherwise stated.

Fig. 3. Stratigraphical diagram, showing the range of Fusiteuthis Kongiel on the north European belemnite zonal scale. This scale was critically assessed by Christensen (1996), who noted that the Early Maastrichtian Belemnella zones are either interval or total range zones. Moreover, he showed that the base of the B. kazimiroviensis Zone is highly diachronous and becomes progressively younger from the eastern part of the Russian Platform in the east to the Netherlands in the west.The zone is Late Maastrichtian in the east, late Late Maastrichtian in Denmark and latest Maastrichtian in the Netherlands.