Contr. Tert. Quatern. Geol. 32(1-3) 53-85 2 figs, 2 tabs, 6 pis. Leiden, June 1995

Pliocene gastropod faunas from Kallo

(Oost-Vlaanderen, Belgium) —

Part 1. Introduction and Archaeogastropoda

R. Marquet

Antwerp, Belgium

Marquet, R. Pliocene gastropod faunas from Kallo (Oost-Vlaanderen, Belgium) — Part 1. Introduction and Archaeogastropoda. —

Contr. Tert. Quatern. Geol., 32(1-3): 53-85, 2 figs, 2 tabs, 6 pis. Leiden, June 1995.

Archaeogastropods from Pliocene strata exposed at Kallo, province of Oost-Vlaanderen (Belgium) are revised, and their stratigraphical and geographical occurrence discussed. Six taxa have not been described previously from the Pliocene of Belgium, viz. Emarginula rosea Bell, 1824, E. crassa crassalta Wood, 1874, Calliostoma (C.) aff. noduliferens (Wood, 1872), Gibbula (Colliculus) crassistriata

(Bell in Wood, 1882), Skenea (Lissospira) basistriata (Jeffreys, 1877) and Dikoleps pusilla (Jeffreys, 1847). Calliostoma (C.) kickxii

(Nyst, 1835) is considered distinct from Calliostoma (C.) zizyphinum (Linné, 1758). Gibbula (Colliculus) petala is described as new.

Sections of the Kallo and their described in detail and discussed. (temporary) exposures geographical setting are

Key words — Gastropoda, Archaeogastropoda, Pliocene, North Sea Basin, taxonomy, stratigraphy, new species.

Dr R. Marquet, Constitutiestraat 50, B-2060 Antwerpen, Belgium.

Contents As early as the 1840-50s fossils were collected in the

study area from sandpits exploited at Kallo and Doel,

Introduction p. 53 others Dewael who amongst by (1853), published a

The North Sea Basin Pliocene 54 p. species list and by Nyst, who also collected at Doel 56 Stratigraphy p. sandpit. Material 60 p. Van den Broeck (1874) and van den Broeck in Nyst 60 Systematic descriptions p. (1881) combined faunal lists for both localities. From Acknowledgements 71 p. Kallo, 73 and 71 species, respectively, were mentioned, References 71 p. from Doel 70. Unfortunately, none of the 19th century

palaeontological collections are stratigraphically well

documented. From these faunal lists, however, it appears

Introduction that not all species could have originated from the same

bed. At Kallo, the following species were collected: the

For over twenty years, collecting from the harbour bivalves Spisula inaequilaterata (Nyst, 1843) (typical for construction works at Kallo (near Antwerp) has yielded Merksem Member), Pecten complanatus (J. Sowerby,

Laevicardium an enormous amount of excellently preserved and pa- 1822), parkinsoni (J. Sowerby, 1818), laeontologically important biota. Various groups repre- Arenomya arenaria (Linne, 1758), the gastropods Litto- sented in this fossil fauna (e.g. shark teeth, foraminifera, rina suboperta (J. Sowerby, 1813), Eulimene terebellata echinoids, and molluscs from the Kattendijk Formation (Nyst, 1835) (Kruisschans Member), and the bivalves and the Kruisschans Member [Lillo Formation]) have Cerastoderma belgica hostiei (Chavan, 1941) (top been described in the literature by a number of authors. Oorderen Member), Laevicardium decorticatum (Wood,

In the present paper, an attempt is made to provide a 1840), Lajonkairea rupestris lupinoides (Nyst, 1836), and synthesis of the entire Pliocene molluscan faunas, all Solecurtus scopula (Turton, 1822) (Oorderen Member). representatives of which appear to occur at Kallo. Quite Species restricted to the Kattendijk Formation were not a number of species are here recorded for the first time recorded, which holds true also for the distinctive from the Pliocene of Belgium. subspecies of the bivalve genus Atrina from the Oorderen 54

Kallo did extend works started about 1986 and the construction Member. Apparently, the outcrop not comprised below the Cultellus bed of the Oorderen Member. The of the Liefkenshoektunnel under the Scheldt.

A species list for Doel yields the same, 'mixed' impression: large pit was dug for the construction of the

and the for this which later recorded are the bivalve Spisula inaequi-laterata separate portions tunnel, were only

assembled the bed. Portions for the gastropod Potamides tricinctus (Brocchi, 1814) (Merksem on river Piet

Member) and the bivalves Laevicardium parkinsoni, Heyntunnel at Amsterdam (The Netherlands) were

Lentidium and constructed there well. This will later be complanatum (J. Sowerby, 1822) gastro- as pit incorpo- pods Nucella incrassata (J. Sowerby, 1823), Admete rated into the Verrebroekdok, the construction of which

viridula (Fabricius, 1780) (Kruisschans Member), the will probably start in 1995. In Fig. 1 the location of the bivalve Clausinella imbricata (J. de C. Sowerby, 1826) various docks is shown. and the gastropods Epitonium foliaceum (J. de C. The first paper describing the stratigraphy and faunas

Sowerby, 1825), Cirsotremaf. fimbriosum (Wood, 1848) of strata exposed in the modern Kallo works is by and Mitrella scaldensis (van Regteren Altena, 1956) Marquet (1972), who provided a stratigraphical section

and list of 74 be (Oorderen Member) are mentioned together. a molluscs, comprising only species, to

followed Gaemers & Unfortunately, the mixed character of these samples by Janssen (1972), containing a

section with of the lock A was not recognised timely, and part of the Belgian interpretation, sea exposure.

detailed section of the Kanaaldok Pliocene (or former 'Scaldisian') was consequently pit was provided by

while Gaemers collectively known as the 'Sables de Callo' (Dumont, Janssen (1974), (1975a, b) presented a

discussion of this section. In the 1839) or 'Sables de Kallo' (de Heinzelin, 1955; Glibert, palaeoecological same

1957, 1958a, b, 1959, 1960). Because of the ambiguity of period appeared a paper by Herman (1974), describing a these stratigraphical terms, de Meuter & Laga (1976) number of species of shark from the Kattendijk Forma-

& rightly proposed the Oorderen Member (Lillo Formation) tion, new for the Pliocene of Belgium. Geys Marquet for the middle Pliocene of Belgium. (1979a) described a well-preserved specimen of the

In the early 1970s the extensive works for the echinoid Strongylocentrotus pallidus (G.O. Sars, 1871),

construction of the Antwerp Left Bank harbour started, which record served to illustrate the excellent preserva-

tion. Molluscs from Kallo described and they continue to the present day. First, a new sea were by Marquet lock was constructed to connect the new harbour with the (1984, 1986).

Scheldt River, to be followed by the first dock, the Microfossils from Kallo were described by Nuyts

Waasland Kanaaldok. Simultaneously, a tunnel was built (1984, 1990), who studied foraminifera from the under this dock. Vrasenedok (Vierde Havendok) and the biozonation of

the Rupel Formation (Oligocene) to Lillo Formation

(Oorderen Member).

Hoedemakers & Marquet (1992) published a new

section from the works in the Liefkenshoektunnel

elements construction pit, paying particular attention to

Member Kallo. the presence of the Kruisschans at

Marquet (1993) studied in detail the molluscan faunas

from that unit, and described a new gastropod species. A

new bivalve subspecies from Kallo has recently been

described by Marquet & Vervoenen in Marquet (1995).

Vervoenen (1995) discussed the taphonomy of the

various shell beds as exposed at Kallo.

THE NORTH SEA BASIN PLIOCENE

During the Pliocene, parts of Holland, England and

Belgium were inundated by the North Sea. Probably, a

1. the docks and to climate in the Fig. Map showing location of various expo- warm temperate subtropical prevailed

sures in the Kallo area, with indication of the sections. North Sea Basin during the Pliocene, comparable with

that found nowadays between Lisbon and Agadir, with

winter water temperatures between 14 and 16°C and

From 1974 onwards followed the construction of the between 20 and 22°C summer water temperatures

Vrasenedok Vierde or Havendok. The last stage of the (Lozouet, 1986). 55

FORMATION MEMBERS PLIOCENE Kallo

Merksem/Poederlee Merksem/Poederlee present

Kruisschans late present Lillo

- lower: Amerika-

dokgravel absent

Oorderen (= Kallo)

- upper: Angulus benedeni

(= Austruweel) middle presentpresent

- - middle: CultellusCultellus

and Atrina presentpresent

- - lower:lower: basal bed presentpresent

Luchtbal remaniéremanie

Kattendijk early

- upper:upper: Ditrupa remanieremanié

- Kattendijk - middle: Petaloconchus present

- - lower: basal basal gravel present

Table 1. Lithostratigraphical units of the Belgian Pliocene.

Pliocene strata are known from borehole cores from Pleistocene into five molluscan zones and two subzones. all over The Netherlands, at at His and mostly great depths. Only MOL A B zones are of Pleistocene age. Zone

the 'de Kauter' Namen, Zeeuwsch quarry (Nieuw MOL C, with the gastropod Nassarius propinquus (J. de

Vlaanderen) do Pliocene strata outcrop. C. Sowerby, 1825) and the bivalve Lentidium compla-

The gastropod faunas recovered from the above- natum, undoubtedly corresponds with the Kruisschans and

mentionedboreholes were studied by Tesch (1912), who Merksem members of the Lillo Formation, although

list and Beets who provided a species only, by (1946), Spaink (1975) correlated that zone with the Oorderen

described and illustrated his specimens. Their material Member of the same formation. The Oorderen Member

included taxa of Pleistocene age, and both works lack appears to be the equivalent of Spaink's subzone Dl,

subdivision into units. Of the the stratigraphical gastropod although species listed for that subzone are not

faunas described Beets about 105 characteristic of by (1946) species may a particular horizon. Zones D2 and E be considered Pliocene. The fossil to be typically fauna, correspond, at least in part, to the Kattendijk Formation,

found washed ashore on Dutch beaches, in particular that but it is not clear where the Luchtbal Member should be

from the Scheldt in the of but since estuary province Zeeland, placed, none of the typical molluscan species of also those from the studied that unit Wadden, was by van were recorded by Spaink (1975).

al. In Regteren Altena (1937) and by van Regteren Altena et Great Britain (mainly East Anglia) many highly

(1965). This material comprised Pliocene as well as fossiliferous deposits outcrop. A tiny spot at St Erth

Pleistocene forms, and cannot be assigned to specific (Cornwall) has also yielded an important Pliocene stratigraphical units. A total of about 160 gastropod molluscan fauna, but that locality was situated outside the species could have originated from Pliocene deposits. North Sea Basin, with the Channel still closed. The

Quite a large material is known from the Scheldt estuary, British Pliocene gastropod faunas were first studied in dredged up and brought ashore at Ellewoutsdijk (for- detail by Wood (1839, 1842, 1848, 1856, 1872-74, 1879,

and Yerseke of These merly) (now) (province Zeeland). 1882), although earlier authors had already described a

faunas Pliocene and Pleistocene forms. The of comprise large number species. Wood's papers record a total of present description of the in situ molluscan faunas from 345 Pliocene and Pleistocene species. Harmer's (1914-18,

Kallo be in this material in its monumental work is revision of Wood's may helpful seeing proper 1920-25) a

context. stratigraphical papers, but includes also the St Erth fauna. An astonish-

Spaink (1975) divided the Dutch Pliocene and ing number of 766 species is listed by Harmer. Of these, 56

53 species are terrestrial, and can be excluded when STRATIGRAPHY comparing this with the Kallo fauna. The number of the

is Harmer Five sections Kallo illustrated in remaining species greatly exaggerated: was an temporary at are Fig. 2: inveterate unidentifiable 'splitter'. Many fragments were those at the sea lock (Gaemers & Janssen, 1972), at the assigned by him to fossil or modern species, or described Waasland Kanaaldok (Janssen, 1974), at the fourth as new. Harmer's papers are in need of a modern revi- harbour dock (Vrasenedok) (Nuyts, 1984 and Janssen sion. [unpubl. 1984]), and at the Verrebroekdok (tunnel

In France, comparable faunas of possible Pliocene age elements) (Hoedemakers & Marquet, 1992). are to found in where are to the Brittany, they assigned The original ground level of all sections are calibrated so-called Redonien. which of these faunas is the the However, at same depth. In course of the harbour works,

Miocene and which Pliocene cannot be decided at sands from the construction pits were scooped up over

On otolith Gaemers present. gadid evidence, (1988) the entire area. This means that this original zero-level is assigned the Redonien to his Zone corresponding with now 17, situated at a depth of c. 5 m, as is seen in the most the Kattendijk Formation, but the molluscan faunas do recent section, published by Hoedemakers & Marquet not appear to support such an assignment of the entire (1992).

Redonien. faunas from this unit were described Gastropod The deepest part of the section, as published by

Brebion but formal has not by (1964), a publication yet Janssen (1974) and Nuyts (1984) exposed a dark grey come out. R with of the clay, clay septaria, upper part of the Boom

In Germany, marine Pliocene which corresponds to Member (Rupel Formation, middle Oligocene). Seven the of the Lillo encountered in upper part Formation, was metres at the most of this formation were exposed, the a borehole at Niitterden near Kleve and described by underlying unit not having been reached. An interesting

Oppenheim (1915). On the basis of heavy mineral fauna, characterised by the bivalve Yoldia deshayesiana

considered of the analyses, Burger (1986) part Morsum (Nyst, 1835) and the nautilid cephalopod Aturia aturi

Cliff section the Isle of be on Sylt (northern Germany) to (Basterot, 1825) was collected from this unit. of early Pliocene it is considered to age, although mostly The basal gravel [Kb], assigned to the Kattendijk be of a late Miocene date Gaemers, In the (e.g. 1983). Formation and observed resting directly on Rupel Clay,

'Geschiebe' in northern Pliocene (boulders) Germany, no consisted of greyish, rather coarse sand with black, faunas have so far been recognised. eroded phosphorites and other pebbles. Reworked

In Scandinavia Pliocene strata are unknown. In of fragments septaria were also common, which evi- northern Iceland, however, indurated Pliocene deposits dences that part of the Rupel Formation was eroded. occur at Tjornes. The molluscan faunas from these Strata of late Oligocene (Chattian) and Miocene age are

with 103 described deposits, gastropod taxa, were by absent. A few fossils of Miocene age are found in the

Schlesch (1924). A few species occur also in the Pliocene basal gravel. The occasionally well-preserved carapaces of Belgium. of the crab Coeloma rupeliensis Stainier, 1887, occurring

On the Pliocene North Sea extended in Belgian territory, small, septaria-like concretions, are undoubtedly of into the province of Antwerp. In the Antwerp city area, Oligocene age. Vertebrate remains are abundant in the the succession of Pliocene is the deposits most complete, basal gravel deposit, especially shark teeth, and whale and often (temporarily) exposed in harbour construction and seal bones. On account of its excellent preservation,

Table 1 lists the units pits. lithostratigraphical currently part of this vertebrate fauna must be autochthonous; a

in the Pliocene. and south employed Belgian East, west large part, however, is reworked from Miocene strata. of the Pliocene become thinner: Tielrode city, deposits at Internal moulds of a typically Miocene bivalve (Panopea (west of Broechem and Boechout Antwerp), (east) inflata Goldfuss, 1841) occur at this level at Kallo, a

the Pliocene is (southeast), essentially developed as a species known exclusively from the Miocene in Belgium.

or reddish basal of 1 or 2 m grey gravel, thickness, Other molluscan species in shell preservation are un-

elements from the entire middle comprising Pliocene, doubtedly autochthonous elements. often mixed with Pleistocene terrestrial elements. To the The main body of the Kattendijk Formation comprises east, these deposits are underlain black sand and by rather coarse, dark gray, glauconitic sand, with various

in which molluscs occur as moulds in nodules shell gravel, beds. The lowest part consists of strongly This unit could the Formation. only. belong to Kattendijk bioturbated sands, which contain gravel with phos- Further in the east, Campine a reddish sandstone is Gravel is absent from the area, phorites. higher parts of the found around Kasterlee and which contains formation. Poederlee, Beds with different types of burrows are internal moulds of shells. This Poederlee Member only separated by horizontal 'clefts', which probably represent may be correlatable with the Merksem Member. erosion levels. 57

Fig. 2. Stratigraphy of temporary sections at Kallo; A - after Gaemers & Janssen (1972); B - after Janssen (1974); C - after Janssen

- (1984, unpubl.); D - after Nuyts (1984) and E after Hoedemakers & Marquet (1992). 58

K Kb KP 0O Ob OAt OC OAn Kr M

Diodora graeca Xx

Emarginula cancellata

E. fissurafissura f. reticulata Xx XxxX Xx

E. rosea xX

E. punctura Xx

E. c. crassa xxX X xX

E. c. crassalta Xx

Anatoma crispata xX

Scurria compressiusculacompressiuscula

Cocculina miocaenica

scaldensis Lepeta (L.)(E.) XxxxX X

Margarites trochoides Xx xX

M. belli

Solariella maculata xxX X xX

Calliostoma zizyphinum xxX X xX

C. simile X XX X X XX

C. occidentale X

C. kickxiikickxii X

C. aff. noduliferens X

C. multigranum

Gibbula solarium X

G. gelriana

G. cineroides

G. octosulcata XX XXXX X X XX

G. beetsi XXXX XX

G. o. forma obconica XX

G. o. forma nehalenniae X X

G. crassistriata X

la G. petapetala X

G. woodi

Skenea basistriata XX X

Dikoleps pusilla X X

Table 2. Stratigraphical distribution of all species of archaeogastropod from the Belgian Pliocene (Kallo sections) known to date.

Abbreviations: K - Kattendijk Formation (unspecified); Kb - Kattendijk Formation base; KP - Kattendijk Formation,

- Petaloconchus bed; O Oorderen Member (unspecified); Ob - Oorderen Member base; OAt - Oorderen Member, Atrina

bed; OC - Oorderen Member, Cultellus bed; OAn - Oorderen Member, Angulus benedeni bed; Kr - Kruisschans Member;

M - Merksem Member.

E-W oriented gullies, most of them comparatively These sedimentary structures indicate interrupted deposi- small and reach- erosion and the influence of (10-15 cm deep 1,2 m wide), but some tion, strong currents ing in certain places a considerable width and depth (to (Gaemers, 1975a, b).

3 m depth). The evolution of these gullies are the cause The lowest part of the formation yields many large of different kinds of sedimentation structures, such as foraminifera, eroded shells and a few otoliths. Higher in oblique bedding and parallel laminations. The larger the section, large forams become rarer, otoliths are gullies may contain two types of burrows: c. 1 cm wide, commoner and shells better preserved, often still articu- vertical which of lated. The shells fugichnia, point to deposition large larger are generally not concentrated; at

quantities of sediment over a short time period, and 2-3 about 17 m a bed with larger bivalves and at 18 m a bed

horizontal burrows. These burrows with Pectinidae Scattered the mm wide, mostly are may occur. throughout

indurated and free formation found vertebrate whales in mostly slightly prepared by the wind. are bones, particular 59

being well represented. Several skeletons were seen in the kasteel and the Schijnpoort underground station at

temporary sections, but due to the rapid advance of the Antwerp, was eroded at Kallo. The overlying Luchtbal

works (and contractors objecting to collecting) these Member is also missing at Kallo. Its former presence is

could be recovered. However, number of skulls the in the basal of rarely a proved by occurrence crag many of toothed and baleen whales have been excavated almost lumps of eroded, yellow sandstone, containing the bivalve

intact. Shark teeth are splendidly preserved and comprise Palliolum gerardi (Nyst, 1835). This sandstone has also

many species. yielded small regular echinoids, and often show bivalve

The most bed far molluscan faunas important as as borings. Other shells in the basal crag are autochthonous;

are concerned is without doubt the Petaloconchus bed whale bones and shark teeth are common. Higher in the

[KP], which was discovered at a depth of 12-13 m, Oorderen Member, vertebrates become much rarer.

above the middle of the Formation. The Atrina level consists of rather slightly Kattendijk [OAt] coarse,

The lower of this bed consists of 10 reef- part a cm thick, occasionally slightly indurated yellowish grey sand, with

like network of tubes of the gastropod Petaloconchus many articulated specimens of Atrina pectinata kalloen-

intortus (Lamarck, 1818). Amongst these tubes lived a sis Marquet & Vervoenen in Marquet, 1995. These shells

highly remarkable molluscan association, described by were observed in (upright) life position in the sea lock

which fissurellids and chitons Marquet (1984), amongst construction pit (Gaemers & Janssen, 1972), but at the

of are note, which are otherwise characteristic of a rocky other localities they were only found lying flat. Many

substrate. About 10 above this level other this cm occurs a concen- molluscan species occur in bed as well, as do

tration of vertical Ophiomorpha crustacean burrows, of regular echinoids (Strongylocentrotus pallidus), which about 3 wide and cm 15 cm long. Many of these burrows may even preserve spines and lantern (E. Huysmans

contain numerous minute fish bones, occasionally found Collection). This level consists mainly of shallow gullies

in anatomical connection. Between the burrows, a and which in all directions, oblique layers, may run

molluscan fauna is found which differs from the under- giving a rather chaotic outlook. This horizon is capped by

Petaloconchus and which is characterised lying bed, by an erosion surface and an overlying coquina. The litho-

the small bivalve Similipecten similis (Laskey, 1811). It logy changes considerably at this erosion surface: the

is striking how small most molluscs remain in the sediment becomes red, it is much finer than that of the

Petaloconchus bed at Kallo. This holds especially true for underlying horizon and often slightly indurated. The basal

the bivalve Neopycnodonte cochlear (Poli, 1795), which layer is characterised mainly by large, often articulated

Kallo maximum size of 3 at grows to a cm at the most. specimens of the bivalve Pygocardia rustica rustica (J.

Specimens from the same level, dredged from the Sowerby, 1818). Higher up, this species becomes less

Westerscheldt and brought ashore at Ellewoutsdijk common and the shells are not packed as densely as in

and Yerseke much and reach the bed. (formerly) (now), are larger basal Extremely fragile species, such as the

10 cm. Large-scale collecting and analysis of the bivalve Cultellus cultellatus (Wood in Sowerby, 1844)

molluscs from this level has increased our knowledge of and Ensis hausmanni (Goldfuss, 1841) are common. This

Pliocene molluscan faunas from the Antwerp area level is referred to as 'OC' in Table 2; it contains few

considerably. sedimentary structures.

Resting discordantly upon the Kattendijk Formation is The Oorderen Member terminates with a bed of

the basal shell bed (Ob] of the Oorderen Member (Lillo clayey sand [OAn], the base of which is a compact shell

Formation). The contact between both formations is bed, which yields mainly articulated specimens of the

abrupt and the basal bed is strongly undulate. The basal bivalve Angulus benedeni benedeni (Nyst & Westendorp,

in this depressions bed were interpreted as load casts by 1839), a species occurring also in the underlying parts of

Gaemers (1975b), being the result of unequal distribution the same member, but more rarely. These shells often of weight on the sea floor. The basal layer consists of a preserve traces of colour. The other shells at this level are rather compact crag, which may contain rock fragments mostly rather eroded and occasionally crushed. Gaemers and whale bones. of this During deposition bed, part of & Janssen (1972) assumed this bed to have formed in a

the Formation eroded tidal Kattendijk was and redeposited. area. A gastropod species which at Kallo occurs

This follows from the presence of numerous, internally most frequently at this level, is Ellobium pyramidale (J. slightly indurated articulated specimens of the typical Sowerby, 1822), which at other localities is considered

Kattendijk Glycymerididae. The bivalve Glossus humanus typical of the Austruweel Member. At Kallo, this horizon

(Linne, 1758), one of the most important index fossils of is possibly the lateral equivalent of that member.

the Kattendijk Formation, is found mostly in this basal Resting upon the Oorderen Member is the

layer at Kallo. This proves, that the shell bed with Kruisschans Member [Kr]. This unit consists of fat, dark

Glossus and the Glycymeris, serpulid Ditrupa, typical of grey clay, which follows without clear boundary on the the upper part of the Kattendijk Formation at e.g. Noord- Angulus bed. Intercalated in this clay are nests of rather 60

coarse, yellowish sand with clay pebbles. Specimens of genuine impoverishment of the fauna, with the exception the bivalve Laevicardium parkinsoni, the most important of the Oorderen Member basal bed, which is really un-

in index fossil of this member, occur this unit. The derrepresented. horizontal basal layer of the Kruisschans Memberconsists The smallest species were not found, not even in the of bed with remanie shell material. The of 1 mesh residue For that unsieved a upper part mm samples. reason, this member show of 5 and consists of sand sorted under binocular Random may a dip to 15°, was a microscope.

and a number of gullies oblique layers. The complete set samples contained only few of the smallest gastropod suggests a shallow open sea (depth less than 10 m) species. But, large shells, such as Scaphella or Galeodea, environment. The shells in the sand larger lenses are may yield remarkably preserved faunules of small and often broken, and occasionally crushed under the load of often extremely fragile species. Being protected against the overlying clay. Larger gastropods are often empty, abrasion, these species were better preserved inside these and not filled with sand, which increases their fragility. larger gastropods shells.

could sedimentation. This point to very rapid The fauna The material collected is contained in the collections of this unit is much more diverse than previously as- of the author. The illustrated specimens are deposited in sumed. Some species appear to suggest climatic cooling the type collection of the Koninklijk Belgisch Instituut

(Marquet, 1993). voor Natuurwetenschappen (Brussels). Material from a

Overlying the Kruisschans Member is the Merksem number of private collections is also covered in the

Member 'M' of the Lillo Formation. At Kallo, this unit as from the Petaloconchus present paper, are specimens is rather thin, especially in comparison with its thickness bed in the collections of the Nationaal Natuurhistorisch on the Scheldt right bank. It is a light green, clayey unit, Museum (Leiden). with a poor fauna, composed almost entirely of articu- lated specimens of the bivalve Corbula gibba gibba Oli- vi, 1792. SYSTEMATIC DESCRIPTIONS

Deposits resting on the latter unit are of Holocene

The peat layer attain a respectable thickness and age. may - Abbreviations are as follows: KBIN Koninklijk contains many semi-carbonized tree trunks. Generally, Belgisch Instituut voor Natuurwetenschappen/Institut few animal remains At in the occur. one locality royal des Sciences naturelles de Belgique, Brussels;

Kanaaldok a was discovered in this unit which was gully NNM - Nationaal Natuurhistorisch Museum, Leiden. filled by fresh water deposits, rich in terrestrial shell

and with material, vertebrate remains. The youngest in situ at Kallo is the a deposit polder clay, grey clay, Superorder Archaeogastropoda Thiele, 1925

deposited in brackish water, and containing of but many Order Vetigastropoda Salvini-Plawen & Hasz- a few species, mostly the bivalves Scrobicularia plana prunar, 1987 and Cerastoderma (da Costa, 1778) glaucum (Poiret, Superfamily Fissurelloidea Fleming, 1822 1789). Family Fissurellidae Fleming, 1822

Subfamily Diodorinae Odhner, 1932

Genus Diodora Gray, 1821

MATERIAL

The present study is primarily based on personal collec- Diodora graeca (Linné, 1758) ting and observations, between 1971 and 1994, in the PI. 2, Fig. 1 various sections exposed during the Kallo harbour works.

1758 Material was handpicked from all levels encountered, and Patella graeca Linne, p. 784.

1848 Fissurella Linn. — sediment samples were sieved on 1 mm and 5 mm graeca Wood, p. 168, pi. 18,

4. meshes. The Petaloconchus, Atrina and Cultellus beds fig.

1872 Fissurella costaria Wood, p. 90, pi. 7, fig. 29. and the Kruisschans Member in particular were sampled

1878 Fissurella Lin. — Nyst, pi. 2, 2. From each of these residue graeca, fig. extensively. beds, a sample of

1881 Fissurella — graeca, Lin. Nyst, pp. Ill, 112. at least 50 kg was handpicked. Smaller samples were

1923 Fissurella — italica, Defrance Harmer, p. 771, pi. taken from the Kattendijk Formation basal gravel, the 61, fig. 17. Oorderen Member basal bed, the Angulus benedeni level

1923 Fissurella — graeca (Linné) Harmer, p. 770, pi. and the Merksem Member. Faunas from these levels are 61, fig. 18. as a less well represented, but the low consequence 1965 Diodora — apertura (Montagu, 1803) van Regteren of their molluscan faunas from diversity follows firstly a Altena et 7. al., p. 8, pi. 1, fig. 61

1957 Diodora dorsata — apertura Monterosato, sp. 1875 Discussion — This species is recorded here for the first Glibert, 7. p. time from the Pliocene of Belgium. It is slightly less

1988 Diodora (Linne, 1758) — Graham, 70, graeca p. common in the Petaloconchus bed than the following fig. 17. species, which it resembles closely. There is much

confusion about the proper name to apply to this species.

Graham (1988) used Emarginula conica Lamarck, 1801 Dimensions — Height 15 mm, width 40 mm. and considered E. rosea to be a synonym. Sabelli et al. Description — Patelliform, medium-sized shell, lacking (1990) and Poppe & Goto (1991), however, preferred slit, but with apical hole at about one third of shell length Bell's name and considered E. conica to be a synonym of from the anterior end. Apical hole oval, thickened on the E. fissura (Linne, 1758). Lamarck's (1801) original shell's interior. Ornament consisting of numerous radial description of E. conica, however, refers explicitly to and slightly weaker concentric ribs. The radials are ’Patella fissura L.', for which it appears to be a new occasionally equal in strength, some specimens have one name. Recent North Sea specimens and fossils from the or more secondary ribs between primary ones. Eemian ('Assise d'Oostende') of the Belgian coast are Discussion — Diodora apertura (Montagu, 1803) is larger than the Kallo shells, while their secondary and considered by most neontologists to be synonymous with primary ribs are more equally developed, especially when Diodora graeca (Graham, 1988; Poppe & Goto, 1991). the shells are not completely fresh. The ornament inside The Kallo than specimens are larger most Recent shells, the groove is more pronounced. Recent specimens are and thus approach the Mediterranean species Diodora found from the British Isles to the Mediterranean, from italica (Defrance, 1820), but differ in showing a more the sublittoral to depths of 30 m (Graham, 1988). convex posterior side and more concave anterior side. At

the Kallo, present species occurs more frequently in the

Kattendijk Formation. From the Kruisschans Member, a Emarginula punctura Wood, 1848 single fragment was collected. Miocene North Sea Basin PI. 1, Fig. 1 material belong to another species (Janssen, 1984).

Diodora is found in graeca at present Mediterranean, 1842 Emarginula Wood, 528. Arctic punctura p. and Atlantic waters, from the littoral zone to 250 1848 Emarginula fissura var. punctura Wood, p. m depth, on rocks or shells (Graham, 1988). 164, pi. 18, fig. 3b.

1872 — Emarginula fissura var. punctura Wood

Wood, p. 90, pi. 7, fig. 24. Subfamily Emarginulinae Gray, 1834

1923 T. Bell — Emarginula rosea, Harmer, p. 779, Genus Emarginula Lamarck, 1801 pi. 62, fig. 10 (partim).

1957 Emarginula punctura Wood, 1848 — Glibert,

1. p. 5, pi. 1, fig. Emarginula rosea Bell, 1824

PI. 1, Fig. 2

Dimensions — Height 4 mm, width 5,4 mm. 1824 2. Emarginula rosea Bell, p. 52, pi. 4, figs 1, Description — The shell form of this species closely

1923 — Emarginula rosea, T. Bell Harmer, p. 779, pi. resembles that of the previous species. The ornament 62, fig. 10 (partim). consists of about 17 strong primary radial ribs; in 1965 Emarginula conica Lamarck, 1801 —van Regteren between, 3-4 much weaker secondary ribs occur. Concen- Altena 3. et al., p. 7, pi. 1, fig.

tric ribs are absent. Between the radials, a fine granula-

1988 conica 1801 — Emarginula Lamarck, Graham, p.

tion is seen. 66, fig. 15b.

Discussion — Wood (1842) only listed the species name

but did not provide a description nor a figure (nomen

Dimensions — 4 width Wood's illustration is not too Height mm, 5,5 mm. nudum). (1848) good, but

— his 1872 Description Small, patelliform shell, with the apex figure is unambiguous. In Great Britain, this

near or over the posterior edge, below the highest point species is known from the Coralline Crag. In Belgium, it of the shell. A slit occurs in the anterior margin and occurs in Kattendijk Formation as well as in the Luchtbal

continues to the The consists Member. It be as a groove apex. ornament seems to an endemic North Sea Basin of radial and concentric ribs, with c. 16-18 strong primary species. Specimens from the Luchtbal Member (KBIN

ribs, and in between, a single slightly weaker secondary collections, illustrated by Glibert, 1957) are larger and rib. The concentric ribs (about 20) are as strong as the the apex is situated further from the posterior edge in

radials, and continue into the Petaloconchus bed secondary groove. specimens from Kallo. 62

Emarginula fissura forma reticulata J. Sowerby, 1813 for larger, higher, conical shells, as found mainly in the

PI. 1, Fig. 3 Red Crag and Oorderen Member. It is here interpreted as

a forma rather than as a subspecies.

1813 reticulata J. 33 Emarginula Sowerby, p. 74, pi.

(partim).

1848 Linn. — J. 1813 Emarginula fissura Wood, p. 164, pi. 18, Emarginula crassa crassa Sowerby,

fig. 3a. PI. 2, Fig. 2

1878 Emarginula fissura, Lin. — Nyst, pi. 7, fig. 9.

1881 Lin. — 114. 1813 J. Emarginula fissura, Nyst, p. Emarginula crassa Sowerby, p. 73, pi. 33 (upper

1923 Linne — Emarginula fissura, Harmer, p. 776, pi. figure).

62, 7. 1843 Sow. — fig. Emarginula crassa Nyst, p. 532, pi. 36,

1923 Emarginula fissura var. depressa Harmer, p. 777, fig. 3.

8. Sow. — pi. 62, fig. 1848 Emarginula crassa J. Wood, p. 165, pi. 18,

1946 Emarginula (Emarginula) reticulata Sowerby, 1813 fig. 2a, b, d (non c).

— 22. 1878 J. — Beets, p. Emarginula crassa, Sowerby Nyst, pi. 7, fig.

1965 Emarginula reticulata J. Sowerby, 1813 — van 8.

Altena 2. al., 7, 1, 1881 J. — 113. Regteren et p. pi. fig. Emarginula crassa, Sowerby Nyst, p.

— reticulata 1813 Glibert, J. — 1957 Emarginula Sowerby, 1923 Emarginula crassa, Sowerby Harmer, p. 775,

4. p. pi. 62, figs 1-3.

1923 S.V. Wood — Emarginula crassalta, Harmer, p.

775, pi. 62, figs 4, 5.

Dimensions — 7 mm, width 10 mm. Height 1926 7 Emarginula anassa Dean, p. 21, pi. 1, fig.

— Rather small, shell, with the 1946 1813 — Description patelliform Emarginula crassa Sowerby, Beets, p. 22,

about third of shell width from the apex one posterior pi. 1, figs 1, 2.

The anterior shows which conti- 1957 — 6. margin. margin a slit, Emarginula crassa Sowerby, 1813 Glibert, p.

the The shows 1965 crassa J. 1813 — nues as a groove to near apex. groove Emarginula Sowerby, van

Altena et al., 7, pi. fig. 5. ridges which run parallel to the shell margin. The Regteren p. 1,

1979b Emarginula crassa Sowerby, 1813 — Geys & ornament consists of about 30 strong primary radial ribs, fig. 4. weaker There Marquet, p. 66, pi. 26, with a single secondary in between. are

1988 Emarginula crassa Sowerby, 1813 — Graham, about the p. 20 concentric ribs, which are as strong as 66, fig. 15c. secondary radials.

Discussion — This species differs clearly from both

in the of its in previous species position being — apex, Dimensions Height 25 mm, width 55 mm.

and in a different ornament. It is rare in the larger having Description — Medium-sized patelliform shell, with the

Kattendijk Formation, slightly more common in the apex between the centre of the shell and the posterior Oorderen in the Member, and again rare very end. Anterior margin with slit, which continues as a

Kruisschans Member. Differences between the Recent striated groove to near the apex. Ornament consists of and the species Emarginula fissura (Linne, 1758) present numerous radial ribs, mostly composed of three to four Pliocene Their is identical specimens are slight. ornament The between the ribs show smaller ridges. grooves pits. and the are found in the same apices position. Many Discussion — This is a typical subspecies of the Graham and Sabelli al. authors, e.g. (1988) et (1990) Oorderen Member; in the Kruisschans Member only consider these species identical. There is only a slight collected. it be fragments were At present, seems to a difference in the Pliocene size, specimens being slightly northern species, being most common between Norway

to 14 while Recent ones larger (up mm), only rarely and Iceland (Graham, 1988). There seems to be little or reach 10 mm in length. Also, the height/width ratio no reason to distinguish Recent specimens as a separate seems to be slightly in Pliocene specimens, larger species, as Dean (1926) did. especially in those from the English Red Crag and

Belgian Oorderen Member. This was also observed by

Harmer who more flatter (1923), separated typical, speci- Emarginula crassa crassalta Wood, 1874 from the Coralline mens Crag as var. depressa Harmer, PI. 2, Fig. 3 and by Glibert (1957). High, conical specimens, however,

to occur also in Recent faunas from the Me- J. Sow. — appear 1848 Emarginula crassa Wood, p. 165, pi. 18,

& 79 The ditteranean (d'Angelo Garguillo, 1978, p. fig.). fig. 2c (non a, b, d).

Kallo Petaloconchus bed but 1874 crassalta 90 specimens are high, com- Emarginula Wood, p.

reticulata 1923 crassalta conica — paratively small. The name might be reserved Emarginula var. (S.V. Wood) 63

6 Harmer, p. 776, pi. 62, fig. (non 4, 5). Superfamily Patellacea Rafinesque, 1815

Family Lepetidae Dall, 1869

Dimensions — Height 11 width 12 mm. mm, Genus Lepeta Gray, 1847

Description — Shell closely resembling that of the

previous subspecies, but smaller. In comparison with E.

c. crassa of the same size it is In markedly higher. Lepeta (Lepeta) scaldensis van Regteren Altena, 1954

the is situated closer the addition, apex to posterior PI. 2, Fig. 5 margin.

— Wood's crassal- Discussion (1874) name Emarginula 1843 — Patella aequalis Sow. Nyst, p. 349, pi. 35,

ta was based on Coralline Crag specimens, which show fig. 5.

1848 Tectura — the same differences from Red Crag specimens as do virginea Mull. Wood, p. 161, pi. 18,

specimens from the Kattendijk Formation from those of fig. 6.

1878 Tectura virginea ? Mull. — Nyst, pi. 7, fig. 12 the Oorderen Member. A subspecific distinction seems (partim). appropriate. Harmer (1923) also applied the name E.

1881 Miiller — 119. Lepeta caeca, Nyst, p. crassalta to specimens of Red Crag age, but Wood's

1925 — Lepeta fulva (Miiller) Harmer, p. 878, pi. 65, fig. original description cannot be applied to these. They 36 (partim). rather belong to Wood's (1848) forma conica. Harmer

1946 — Lepeta (Lepeta) caeca (Miiller, 1776) Beets, p. appears to have confused the proper application of the 23, pi. 1, figs 3, 4. E. crassalta and E. The forma is names conica. present 1946 Pilidium — fulvus (Miiller, 1773) Beets, p. 23

confined the Formation in and to to Kattendijk Belgium (partim).

the Coralline of Great Britain. 1954 45. Crag Lepeta scaldensis van Regteren Altena, p.

1957 Lepeta scaldensis Regteren-Altena, 1954 — Gilbert,

9. p.

Supcrfamily Scissurelloidea Gray, 1847 1965 Lepeta scaldensis Van Regteren Altena, 1954 —

van Altena al., 8, 2, 9. Family Scissurellidae Gray, 1847 Regteren et p. pi. fig.

1979b scaldensis Regteren-Altena, 1954 — Geys & Genus Anatoma Woodward, 1859 Lepeta

Marquet, p. 60, pi. 26, fig. 3.

Dimensions — Height 9 mm, width 19 mm. Anatoma crispata (Fleming, 1828) Description — Medium-sized, patelliform shell, its colour PI. 2, Fig. 4 invariably being yellow, and lacking a slit. The

protoconch is smooth, brilliant, tumid and sharply 1828 366. Scissurella crispata Fleming, p. delimited from the teleoconch. Juvenile specimens show 1848 Scissurella Flem. — crispata Wood, p. 163, pi. 15, numerous, granular radial ribs and less fig. 13. pronounced

concentric lines; in mature this ornament 1984 Scissurella (Anatoma) crispata Fleming, 1828 — specimens

338, 3, 2. becomes obsolete. On the shell's interior, a Marquet, p. pi. fig. clearly

1988 Scissurella 1828 — delimitedmuscle is crispata Fleming, Graham, p. impression seen.

60, fig. 13. Discussion — In lacking a slit and showing the distinc-

1992 Anatoma — Cavallo & crispata (Fleming, 1828) tive yellow colour, this species is easily distinguished Repetto, 34, fig. 16. p. from all other patelliform gastropods. It is a typical and

1994 Anatoma crispata (Fleming, 1828) — Gia- common element in the Oorderen Member faunas, and

nuzzi-Savelli et al., p. 50, fig. 92. appears to be endemic to middle Pliocene of the North

Sea Basin.

Dimensions — Height 1 mm, width 2 mm.

Description — Minute, cyrtoconoid shell, with wide,

deep umbilicus. Numerous prosocline radial costae occur, Supcrfamily Trochoidea Rafinesque, 1815

with fine ribs between them. The Trochidae many spiral most Family Rafinesque, 1815

characteristic feature is the slit in the outer lip, which Subfamily Margaritinae Stolizcka, 1868

continues up the spire as a closed slit-band. Genus and

Discussion — So far this species has only been found in subgenus Margarites Gray, 1847

the Petaloconchus bed at Kallo. In Great Britain it is

known from the Coralline Crag. Recent specimens are

found between depths of 8 to 2,000 m; southern records Margarites (Margarites) trochoides (Wood, 1842)

are from deeper water (Graham, 1988). PI. 3, Fig. 4 64

1842 Margarita trochoidea Wood, p. 530. about six tumid teleoconch whorls and a wide open

1848 trochoidea S. Wood — Margarita Wood, p. 136, umbilicus. The protoconch comprises a single smooth,

15, 2. pi. fig. glossy whorl, which is sharply delineated from the

1923 Eumargarita trochoidea (S.V. Wood) — Harmer, p. teleoconch. The teleoconch ornament starts with about 30

752, pi. 55, fig. 14. radial ribs on the first whorl. On the second whorl,

trochoidea — 1957 Margarites Wood, 1842 Glibert, p. 9, radials still the elements of are most important ornament, pi. 1, fig. 3. but two spirals begin to appear, which start as an upper

and a lower keel. Thereafter the radials lose in strength Dimensions — Height 2 mm, width 4 mm.

and remain as tubercles on the spiral ribs. Half a whorl Description — Small, flattened, turbiniform shell with later, the subsutural area above the upper keel is com- five slightly tumid whorls and wide open umbilicus. pletely free of radial ornament. Two secondary spirals Ornament is almost absent; only on the upper part of the with tubercles begin to below the adapical whorls and around the umbilicus appear can very faint spiral primary spiral. The tubercles become more obsolete With the shell lines be seen. upper layer partially peeled towards the aperture. The ornament consists of about 9 off, as is often the case, nacre becomes visible. the last which continue also strong spirals on whorl, on Discussion — This is a rather rare species, with but a the shell base. In the umbilicus, up to the first spiral, single specimen known from the Petaloconchus bed of radial ribs occur. Nacre can be seen there where the the Kattendijk Formation; it becomes less rare higher up upper shell layer is missing. Some specimens show traces in this formation. They differ from Glibert's (1957) of their original colour pattern (see Geys & Marquet, in specimens having spirals, but in this respect they 1979b, pi. 27, fig. 5). coincide more closely with Wood's (1848) illustration.

Discussion — This species is common in the Similipec- Margarites trochoides is a local North Sea Basin early ten bed immediately above the Petaloconchus bed, but is Pliocene species. rare in the other units at Kallo. A few specimens have

been collected from the Atrina level (Oorderen Member).

is endemic North Sea Basin of and It an species early Subfamily SolariellinaePowell, 1951 middle Pliocene age. Katttendijk Formation specimens Genus Solariella Wood, 1842 are narrower and relatively higher than those from the

Luchtbal Member from other localities and than those Solariella maculata Wood, 1842

from the Oorderen Member at Kallo. PI. 3, Fig. 1

1835 Turbo moniliferus Lam. — Nyst, p. 27. Subfamily CalliostomatinaeThiele, 1924 Solariella 1842 maculata Wood, p. 531, pi. 5, figs Genus and 7, 10. subgenus Calliostoma Swainson, 1840 1843 Solarium turbinoides Nyst, p. 370, pi. 36,

fig. 7.

1848 Margarita (?) maculata S. Wood — Wood, p. Calliostoma (Calliostoma) zizyphinum (Linné, 1758) 135, pi. 15, fig. 3. PI. 3, Fig. 2 1878 Trochus turbinoides, Nyst — Nyst, pi. 10, fig.

24. Trochus 759. 1758 zizyphinus Linne, p.

1881 Trochus turbinoides, — 98. Nyst Nyst, p.

1835 Sow. — 26. Trochus laevigatus Nyst, p.

Solariella maculata, — 1923 S.V. Wood Harmer, p. 1839 Trochus & sedgwicki Nyst Westendorp, p. 18. 744, 60, 1. pi. fig. 2. 1843 Trochus laevigatus Nyst, p. 379, pi. 36, fig. 1918 Eumargarita (Solariella) Coss- antwerpiensis 1843 Trochus N. & W. — sedgwicki Nyst, p. 32, pi. 35, 65. mann, p. 259, pi. 8, figs 64, fig. 20.

— 1957 Solariellamaculata Wood, 1842 Glibert, 1848 Trochus Linn. — p. zizyphinus Wood, p. 124, pi. 13,

10, pi. 1, fig. 5. fig. 9a-h.

1878 Trochus conulus ? L. — 26. Solariella maculata — 6, 1965 S.V. Wood, 1842 van Nyst, pi. fig.

1878 Trochus zizyphinus, L. — Nyst, pi. 6, fig. 25. Regteren Altena et al., p. 9, pi. 2, fig. 12.

1879 Trochus Linn. — zizyphinus Wood, p. 34, pi. 4, fig. 1979b Solariella maculata Wood, 1842 — Geys & 20. Marquet, p. 68, pi. 27, fig. 5.

1881 Trochus conulus ? — 101. L., var. Nyst, p.

1881 Trochus L. — 99. zizyphinus, Nyst, p.

Dimensions — 9 width 1918 Calliostoma Height mm, 9,5 mm. antwerpense Cossmann, p. 289, pi. 9,

Description — Medium-sized, turbiniform shell, with figs 50, 51. 65

1923 Trochus (Calliostoma) zizyphinus (Linne) — Har- Calliostoma (Calliostoma) simile (J. Sowerby, 1816) 708, 52, 1-6. mer, p. pi. figs PI. 3, Fig. 3

1923 Trochus (Calliostoma) conulus (Linne) — Harmer,

6. p. 716, pi. 58, fig. 1816 Trochus similis J. 35. Sowerby, p. 179, pi. 81, fig. 1946 Trochus (Calliostoma) cf. zizyphinus (Linne, 1758) 1843 Trochus similis Sow. — Nyst, p. 377, pi. 35, fig.

— 24. Beets, p. 19.

1946 Trochus (Calliostoma) zizyphinus var. 1843 Trochus dekenii 10. (Linne) Nyst, p. 378, pi. 36, fig.

conuloides (Lamarck, — Beets, 25 p. 1848 Trochus sim Sow. — 1822) papillosus var. ilis Wood, p.

(partim). 6c 126, pi. 13, fig. (non a, b). 1957 Calliostoma (Calliostoma) zizyphinum Linne, 1758 1878 Trochus noduliferens, S. Wood — Nyst, pi. 6, fig.

— Glibert, p. 11, pi. 1, fig. 6. 27.

1965 Calliostoma zizyphinum zizyphinum (Linnaeus, 1878 Trochus occidentalis, Migh. et Adams — Nyst, pi.

— van Altena 9, 2, 1758) Regteren et al., p. pi. fig. 6, fig. 29.

13b. 1918 Oxystele nysti Cossmann, p. 214, pi. 7, fig. 26.

1979b Calliostoma zizyphinum (Linne, 1758) — Geys & 1923 Trochus (Calliostoma) conuloides (Lamarck) — 3. Marquet, p. 68, pi. 27, fig. 9. Harmer, p. 706, pi. 57, figs 8,

1988 Calliostoma — Graham, — zizyphinum (Linne, 1758) 1923 Trochus (Calliostoma) granulatus (Born)

41. p. 124, fig. 12. Harmer, p. 711, pi. 57, figs 11,

1993 Calliostoma — zizyphinum (Linne, 1758) Marquet, 1923 Trochus (Calliostoma) similis (J. Sowerby) —

89. p. 16. Harmer, p. 713, pi. 57, fig. 1994 Calliostoma (Calliostoma) zizyphinum (Linne, 1758) 1946 Calliostoma (Calliostoma) zizyphinum (Linne) var. — Gianuzzi-Savelli et al., 158-168. p. 66, conuloides — figs (Lamarck, 1822) Beets, p. 25

(partim).

1957 Calliostoma simile 1818 (Calliostoma) Sowerby, sp.

— 1. Glibert, p. 13, pi. 1, fig. Dimensions — Height 39 mm, width 38 mm; height 35 1965 Calliostoma zizyphinum simile (J. Sowerby, 1818) mm, width 31 mm.

— Altena 13a. van Regteren et al., p. 59, pi. 2, fig.

Description — Medium-sized, rectilinear-conical shell, 1979b Calliostoma simile (Sowerby, 1818) — Geys & lacking umbilicus. Shell slightly keeled at the periphery Marquet, p. 68, pi. 27, fig. 2.

by the of a thick band, which often presence spiral 1993 Calliostoma simile (J. Sowerby, 1818) — Marquet, remains visible above the suture on older whorls. A much 89. p.

lower keel occasionally occurs just below the suture.

Ornament either be absent consist of — may entirely or Dimensions Height 29 mm, width 26 mm; height 20 about 20 weak very spirals, or of a low number of much mm, width 21 mm.

— more conspicuous spirals, as in most Recent specimens. Description Medium-sized, rectilinear-conical shell,

Discussion — The species is typical for the Kattendijk lacking umbilicus. The protoconch consists of half a

but is in Petaloconchus reticulate Formation, not more common the whorl bearing a ornament, and separated from bed than it is in the other portions of this formation. In the teleoconch by a ridge. The shell is often slightly

the Oorderen Member at Kallo, it is replaced by the next keeled by the presence of a thick spiral band, visible species, from which it differs by its usually relatively above the suture. The aperture is rounded-quadrangular.

higher shell, more conspicuous keel and much less Teleoconch ornament is always prominent, and consists prominent spiral ornament. It reappears in the of about 8 spirals on the last whorl. These spirals may

Kruisschans Member. The specimen from the Antwerp bear granules, especially near the suture. Shell base

Pliocene illustrated by Harmer (1923, pi. 58, fig. 6) under shows spirals, which may become obsolete halfway to the the Trochus name (Calliostoma) conulus, might represent centre.

small Discussion — Calliostoma subexcavata a specimen of C. zizyphinum, but the ornament is (Wood, 1846) not figured clearly enough to be certain. Recent speci- from the British Crags, considered to be a synonym by mens occur from the Lofoten to the Mediterranean; they Glibert (1957), is clearly a distinct species, with a higher

differ from Pliocene shells in shell and much and mostly possessing 6-9 coarser more strongly granulate much Calliostoma simile better-developed spiral ribs, but the variation in spirals. occurs in the Oordercn and ornament is wide in Recent shells (well illustrated by Kruisschans members. Only in the latter does it co-occur

Gianuzzi-Savelli et al., 1994, figs 158-168) as it is in with C. zizyphinum. Shell height is very variable, but the fossil material. There seems to be little or no need to mean height/width ratio seems to be lower than that in

the the These separate present Pliocene shells as a subspecies, previous species. species are easily distin- although the names antwerpense Cossmann, 1918 and guished on details of ornament. Calliostoma simile is sedgwicki Nyst & Westendorp, 1839 are available. confined to the middle Pliocene of the North Sea Basin. 66

Calliostoma (Calliostoma) kickxii (Nyst, 1835) specimen from the Oligocene of Kleine Spouwen (prov-

PI. 4, Fig. 2 ince of Limburg, Belgium) should obviously be assigned

to another species. Calliostoma kickxii thus appears to be

Trochus 19. restricted the North Sea Basin and middle 1835 Kickxii Nyst, p. 26, pi. 4, fig. to early

1835 Trochus 20. Robynsii Nyst, p. 26, pi. 5, fig. Pliocene.

Trochus Kickxii — 381, 38, 2. 1843 Nyst Nyst, p. pi. fig.

1843 Trochus — Robynsii Nyst Nyst, p. 26, pi. 382,

fig. 3. Calliostoma (Calliostoma) aff. noduliferens

1878 Trochus Kickxii, Nyst — Nyst, pi. 6, fig. 31. (Wood, 1872)

1878 Trochus Robynsii, Nyst — Nyst, pi. 7, fig. 2. PI. 4, Fig. 1

1923 Kickxii — Trochus (Gibbula) (Nyst) Harmer, p.

737, pi. 59, fig. 15.

1848 Trochus papillosus ? Da Costa — Wood, p. 126, pi.

Trochus — 1923 (Gibbula) Robynsii (Nyst) Harmer, p. 13, fig. 6a, b (non c). 737, pi. 59, fig. 16. Trochus 81. 1872 noduliferens Wood, p.

1836 Trochus — 28. non Kickxii Nyst Nyst, p.

1874 Trochus Wood — 210 noduliferens Wood, p. non1848 Trochus Kickxii Nyst — Wood, p. 130, pi. 14,

1923 Trochus (Calliostoma) noduliferens (S.V. Wood) — fig. 5. 718, 58, 8, 9. Harmer, p. pi. figs

1965 Calliostoma noduliferens (S.V. Wood, 1872) — van

Regteren Altena et al., 9, pi. 2, fig. 14. Dimensions — Height 9 mm (incomplete), width 10 mm. p.

Description — Medium-sized, cyrtoconoid conical shell, with slightly tumid whorls. Periphery slightly keeled. Dimensions — Height 4,5 mm (top not preserved), width Umbilicus absent. Aperture more or less quadrangular. 5,5 mm.

Ornament consists of a single spiral rib just above the Description — Small, near-recticonical shell with slightly suture on the older whorls and just above the keel in the tumid whorls and rather deep sutur s d.e, comprising to youngest one. The spirals closest to the top may bear about 6 teleoconch whorls. The ornament consists of 5 small tubercles. On the basal shell part, 2-4 clearly of small which spiral rows tubercles, are only very delimited spirals be seen. may The slightly interconnected. There is no radial ornament.

Discussion — Glibert (1957) considered this species to shell base is completely covered with 9-10 continuous be a junior synonym of Calliostoma zizyphinum. How- spiral ribs. Much weaker radial growth lines are also constant ever, there to be a few differences appear the base. The is less conspicuous on aperture more or between juveniles of that species and the present taxon. quadrangular. There is no umbilicus. The former is invariably wider and neatly conical. If Discussion — This species has not been recorded is the shell it the ornament present on basis, occurs near previously from the Belgian Pliocene. Only a handful of kickxii periphery or over the entire surface. Calliostoma incomplete specimens have been collected from the on the other hand is narrower and the whorls are tumid. Oorderen Member by F. van Nieulande, but without shell base The presence of spirals near the centre of the specification of horizon. The species differs from juvenile is also typical. Trochus robynsii Nyst, 1835 is considered specimens of the congeners at Kallo by showing slightly synonymous with C. kickxii. Differences between both tumid whorls, ornament consisting of rows of tubercles are well within the of individual variation of the range and of the entire shell base. It presence spirals over latter species. differs from Calliostoma multigranus (Wood, 1848),

Calliostoma kickxii is a rather rare species, which which also occurs in the Belgian Pliocene, but not at the Formation, appears to be typical for Kattendijk Kallo, in being wider and in lacking tubercles on the having been collected from the Ditrupa bed in this basal spirals. The species is known from the British Red formation at Antwerp (Borgerhout and Noordkasteel, Crag and St Erth Beds and from Dutch beach material; Marquet Collection). This bed is absent in the Kallo it to be confined to the Pliocene of the North Sea appears exposures. The sole specimen known from Kallo (van Basin and the Atlantic. Nieulande Collection) came from the base of the

Oorderen Member and may have been reworked from the

underlying Kattendijk Formation. The species is also

known from the British Red Crag. Wood (1848) illus- Subgenus Eucasta Dall, 1898

with trated under this name a specimen many spiral ribs, Calliostoma occidentale which however should rather be referred to one of the (Eucasta)

(Mighels & Adams, 1842) species of the genus Gibbula. Harmer's (1923) figures

PI. 3 correspond with Calliostoma kickxii Nyst's (1836) 4, Fig. 67

1842 531 4. Trochus quadricinctus Wood, p. ( nomen nu- fig.

29. dum). 1872 Solarium vagum Wood, p. 85, pi. 7, fig.

Trochus & 1878 Trochus — 32. 1842 occidentalis Mighcls Adams, p. 47, pi. solarium, Nyst Nyst, pi. 6, fig.

1881 — 106. 4, fig. 16. Trochus solarium, Nyst Nyst, p.

1848 1923 Solarium solarium — Trochus formosus Wood, p. 125, pi. 13, fig. 2. (Nyst) Harmer, p. 852, pi. 64,

1878 Trochus occidentalis, Migh. et Adams — Nyst, pi. figs 41, 42.

7, fig. 5. 1946 Gibbula (Steromphala) solarium (Nyst, 1835) —

1923 occidentalis and 24-27. Trochus (Calliostoma) (Mighels Beets, p. 30, pi. 1, figs

— — 15. 1957 solarium 1835 Glibert, Adams) Harmer, p. 721, pi. 58, figs 14, Gibbula Nyst, sp. p. 15,

10. 1957 Calliostoma (Eucasta) occidentale Mighels, sp. pi. 1, fig.

1842 — 8. Glibert, p. 14, pi. 1, fig.

1965 Calliostoma occidentale (Mighels, 1842) — van

Dimensions — 4 width mm; Kruisschans Altena 16. Height mm, 7,5 Regteren et al., p. 9, pi. 3, fig. Member 13 width 18 1988 Calliostoma occidentale (Mighels & Adams, 1842) specimen: height mm, mm.

— — 43. flattened, near-recticonical Graham, p. 128, fig. Description Fairly large,

carina. The whorls become shell with a marked progres-

sively more concave. The teleoconch ornament at first

Dimensions — Height 14 mm, width 14 mm; height 11 consists of two, then 5-7 spiral ribs, which may bear mm, width 14 mm; height 2,8 mm, width 2,8 mm. tubercles; these are however almost completely oblite-

Description — Medium-sized, rectilinear, keeled (PI. 4, rated by erosion in the available specimens. The tubercles Fig. 3a, b) to slightly concave (Fig. 3c) conical shell, are most pronounced near the adapical suture; the lowest lacking umbilicus. The protoconch consists of about one spiral, which runs on the carina, is smooth. On the shell whorl, which is tumid and bears a reticulate orna- very base, 7-8 spirals occur, which become stronger and more The is rounded. The teleoconch ment. aperture ornament tuberculate towards the umbilicus. The aperture is

starts with two spirals and a number of radial ribs, which The umbilicus is circular, and pointed in its upper part. are of near-equal strength. The radials gradually efface, deep, half closed and marked by strong radial growth in comparison with the spirals, and on the third lines.

teleoconch whorl they are limited to tubercles on the Discussion — This species differs markedly from all The of the whorls consists of spirals. ornament youngest other trochids at Kallo on account of shell shape, base

3-5 very prominent spirals above the peripheral keel, and umbilicus. But a single very incomplete specimen which may bear tubercles, especially near the suture. The has been collected at Kallo (Sea Lock) by A. Janse from shell base is either weakly ribbed with about 15 spirals, the Oorderen Member ( Angulus benedeni bed ?); it

especially near the centre, or almost smooth. preserves the typical umbilicus. A better preserved

Discussion — This species is easily distinguished from specimen from Antwerp is here illustrated. So far, the all congeners in remaining constantly smaller and in present species was known especially from the having more clearly delimited and stronger spiral orna- Austruweel Member and rarely from the Kruisschans ment. It is typical especially for the bed with crustacean Member (Marquet, 1993). In Great Britain, it occurs in burrows immediately above the Petaloconchus bed. It is the Red Crag. rare elsewhere in the Kattendijk Formation and absent

from all younger strata at Kallo. It is a modern northern

species, found in Britain, Scandinavia, Iceland and Subgenus Steromphala Gray, 1847

eastern North America, between depths of 19 and 1,000

m (Graham, 1988). Gibbula (Steromphala) octosulcata (Nyst, 1835)

PI. 6, Fig. 1

Subfamily Gibbulinac Stoliczka, 1868 1835 Trochus octosulcatus 18. Nyst, p. 26, pi. 4, fig. Genus and

1843 Trochus octosulcatus — 323, Nyst Nyst, p. pi. 38, subgenus Gibbula Risso, 1826 fig. 1.

1848 Trochus Adansoni — Payr. Wood, p. 129, pi.

14, fig. 3. solarium Gibbula — (Gibbula) (Nyst, 1835) 1878 Trochus octosulcatus, Nyst Nyst, pi. 7, fig. 1.

PI. 4 1881 Trochus — 107. 4, Fig. octosulcatus, Nyst Nyst, p.

1923 Trochus octosulcatus — (Nyst) Harmer, p. 727, pi

21. 19. 1835 Trochus solarium Nyst, p. 26, pi. 5, fig. 58, fig.

— 1923 Trochus Adansoni — Harmer, 732, 1843 Trochus solarium Nyst Nyst, p. 383, pi. 38, (Payraudeau) p. 68

pi. 59, fig. 8. oblique radial striae, which give the spirals a granulate or

1946 Gibbula octosulcata (Nyst, 1835) — Beets, 25. p. scaly appearance. The primary spirals often preserve their

1957 Gibbula (Steromphala) octosulcata Nyst, 1835 sp. purple or red colour, the secondary ones in between are

— Glibert, 17, pi. 1, fig. 13. p. invariably white.

1965 Gibbula octosulcata (Nyst, 1835) — van Regteren Discussion — Gibbula beetsi belongs to a group of Altena 19. et al., p. 10, pi. 3, fig. species which are difficult to separate. It may be distin-

1979b Gibbula octosulcata (Nyst, 1835) — Geys & of its and fewer ribs and guished on account stronger 6. Marquct, p. 66, pi. 26, fig. often also of preservation of colour pattern. It is re-

stricted to the Oorderen Member, in which it is rarer than Dimensions — Height 14 mm, width 13 mm; height 12 G. obconica, and to the Kruisschans Member. The width 12 9 width 12 mm, mm; height mm, mm. species is endemic to the Pliocene of the North Sea Description — Medium-sized, cyrtoconoid conical shell, Basin, and differs from G. obconica in having a more with rather flattened whorls. The umbilicus is mostly rounded last whorl, a closed umbilicus and coarser, fewer closed, but occasionally a narrow cleft remains. The spiral ribs. height/width ratio is very variable. Spiral ornament is present on the whorls as well as on the shell base, and consists of 6-8 primary spirals and 3-5 weak secondary Gibbula (Colliculus) obconica forma obconica spirals in between. The primary ribs bear small granules. (Wood, 1842) Discussion — Distinctive features of this species are its PI. 5, Fig. 3 size and ornament, which is much finer than in most congeners occurring at Kallo. It is very common in the 1842 Trochus obconicus Wood, p. 532. Oorderen Member, but rare in the Kattendijk Formation

1848 Trochus obconicus Wood — S. Wood, p. 133, pi. and in the Kruisschans Member. The species is restricted 14, fig. 10. to the North Sea Basin Pliocene.

1923 Trochus (Gibbula) obconicus (S.V. Wood) —

22. Harmer, p. 740, pi. 59, fig.

1946 Gibbula 8-12. spastica Beets, p. 26, pi. 1, figs Colliculus Monterosato, 1888 1957 Gibbula obconica 1842 Subgenus (Steromphala) Wood, sp.

forme obconica — Glibert, 16a s.s. p. 19, pi. 1, fig.

Gibbula (Colliculus) beetsi van Regteren Altena, 1954 (partim).

PI. 5, Fig. 1 1965 Gibbula nehalenniaeVan Regteren Altena, 1954 —

Altena 21 van Regteren et al., p. 10, pi. 3, fig.

1923 Trochus — (partim). (Gibbula) philberti (Recluz) Harmer, p.

739, pi. 69, fig. 20.

1946 Gibbula — 26. philberti (Recluz, 1843) Beets, p. — Dimensions Height 6,5 mm, width 5,5 mm.

1946 Gibbula 2 — 33 spec. Beets, p. 31, pi. 1, figs 32, Description — Rather small, cyrtoconoid conical shell,

1946 3 — 35 Gibbula spec. Beets, p. 31, pi. 1, figs 34, with almost completely closed umbilicus. The general 1954 Gibbula beetsi 46 van Regteren Altena, p. shape is the same as that of the following subspecies. 1957 Gibbula (Steromphala) beetsi Regteren-Altena, The ornament consists of about 20 fine spiral ribs above 1954 — Glibert, 14. p. 18, pi. 1, fig. the keel, 15-18 below, which are interconnected by only 1965 Gibbula beetsi Van Regteren Altena, 1954 — van weaker radial On the of inter- 20. slightly ornament. points Regteren Altena et al., p. 10, pi. 3, fig. section, small Gibbula — 1993 aff. beetsi van Regteren Altena, 1954 granules develop.

89. Discussion — At this forma is known Marquet, p. Kallo, exclusively

from the Petaloconchus bed. It differs from G. obconica

Dimensions — width 6 Height 5,5 mm, mm. forma nehalenniae in having granules on the spiral

Description — Rather small, thick-shelled, cyrtoconoid ornament. Topotypical specimens housed in the KBIN conical shell, with closed umbilicus and rounded whorls. collections possess the same ornament, if well preserved.

The is with aperture rounded-squarish, occasionally a In G. spastica Beets, 1946 the '[...] spirals are somewhat

columellar tubercle. The very inconspicuous ornament granulous on account of numerous growth-lines ...' consists of ribs, which with the of strong spiral separated by deep grooves. (Beets, 1946, p. 26), corresponds type

About 5-7 spirals occur on the last whorl above the ornament shown by Kattendijk Formation specimens.

and about 8 below. The distance between them periphery, According to Beets his new species differed from G. is variable. The delimits subsutural obconica in less but this is adapical spiral a having convex whorls, a very

Weaker between depression. secondary spirals may occur variable character in the present material and does not the The ribs crossed close-set primary ones. spiral are by warrant separation on the specific level. 69

Gibbula (Colliculus) obconica forma nehalenniae 749, pi. 60, fig. 8.

van Regtcren Altena, 1954 1965 Margarites crassistriata (R. Bell in S.V. Wood,

— van Altena 2, PI. 5, Fig. 2 1882) Regteren et al., p. 8, pi. fig.

11.

1878 Trochus obconicus, S. Wood — Nyst, pi. 7, fig. 4.

Dimensions — Height 6 mm, width 6 mm. 1881 Trochus obconicus, S. Wood — Nyst, p. 110.

— Rather small, shell, 1946 Gibbula (Colliculus) pennanti (Philippi, 1851) — Description solid, cyrtoconoid

of about five tumid, whorls, Beets, p. 27. consisting slightly angular

1946 Gibbula 1 — with suture. The umbilicus is spec. Beets, p. 31, pi. 1, figs 28-31 a deep nearly closed. The

1954 Gibbula nehalenniae van Regteren Altena, 47. is p. aperture near-quadrangular and possesses a very weak 1957 Gibbula (Steromphala) obconica forme obconica columellar tooth. Older whorls have three strong, clearly

Wood, sp. 1842 — Glibert, 19, pi. 1, fig. 16a p. delimited spiral ribs, which are about as broad as one

(partim). third of the intercostal areas. On the last whorl, two 1957 obconica Gibbula (Steromphala) Wood, sp. 1842 additional weaker spiral ribs appear; one runs near the

forme nehalenniae Regteren-Altena, 1954 — base, the other on the adapical part of the whorl, where 16b. Glibert, p. 19, pi. 1, fig. it causes a narrow subsutural depression to develop. On 1965 Gibbula nehalenniae Van Regteren Altena — van the shell 8 weaker which base, spirals occur, are about as Altena 21 Regteren et al., p. 10, pi. 3, fig. (partim). broad as the intercostal areas. None of the spirals bear 1979 Gibbula obconica (Wood, 1842) — Geys &

tubercles, but brown colour spots may be seen on them. Marquet, p. 66, pi. 26, fig. 5.

Numerous fine, radial striae are present between the

Dimensions — 7 the dorsal of the Height mm, width 6 mm; height 6 mm, spirals on part shell, but not on the shell

width 5 mm. base. They are prosocline, less so in the subsutural

than more Description — Rather small, cyrtoconoid conical shell, depression abapically.

with nearly completely closed umbilicus. The suture is Discussion — This species is here recorded for the first

time from the Pliocene. At it is deep and the flat-sided whorls have a stepwise form. The Belgian Kallo, extremely

in the Oorderen So last whorl has a rounded-keeled periphery. The aperture rare Member. far it was known only

is with often tubercle from the British and Red Dutch beach squarish, a very slight on the Boyton Crags.

columellar side. The ornament consists of 12-20 unequal, specimens, housed in the NNM collections, differ from

fine spiral ribs above the keel, and 18 below. Occasion- Kallo material in having on the last whorl the five spiral

ribs become ally fine radial ornament is seen between the spiral ribs. equally strong. All available specimens are

Some retain their colour thick shelled and could of specimens original pattern, not nacreous, as one expect a

of small reddish while of the which it has consisting spots, others have fewer species genus Margarites, to taxon

and ribs been (about 7) coarser and a lower spire. For speci- previously assigned.

mens such as these van Regteren Altena (1954) coined

the name G. nehalenniae.

Gibbula Discussion — Glibert (1957) is here followed in not (Colliculus) petala n. sp.

PI. 5 considering G. nehalenniae as a separate species, but 5, Fig.

only as a forma with extremely low spire and coarse ribs.

— Colliculus Gibbula obconica forma obconica is clearly different and Diagnosis A species of the subgenus with

never found to co-occur with G. o. forma nehalenniae. ornament consisting of about 7-10 spiral rows of weakly

As early and middle Pliocene specimens need to be interconnected tubercles, with radial sculpture in between.

the oldest available G. Dimensions — Height 5,5 mm, width 5,5 mm. distinguished, synonym,

nehalenniae, is here used for the forma occurring in the Type — Holotype, KBIN/IRScNB no. 1ST 5881; 10

Oorderen Member. At Kallo it is most common in the paratypes (Marquet Collection).

Atrina bed and much rarer in the Cultellus bed. Locus typicus — Vrasenedok, Kallo, municipality of

of Beveren, province Oost-Vlaanderen, Belgium; co-

ordinates (sheet 7/5-6): x = 140,850, y = 216,700 (see

Gibbula (Colliculus) crassistriata Hoedemakers & Marquet, 1992).

(Bell in Wood, 1882) Stratum typicum — Kattendijk Formation, Petaloconchus

bed PL 5, Fig. 4 (early Pliocene).

Derivatio nominis — Alluding to Petaloconchus.

1882 crassi-striata Bell in — Rather Margarita Wood, p. 10, pi. 1, Description small, relatively high, cyrtoconoid

fig. 15. shell, consisting of about 6 rather flat-sided and stepwise

1923 crassistriata — whorls with The Margarites (R.G. Bell) Harmer, p. deep suture. aperture is rounded to 70

slightly squarish. The umbilicus is nearly closed. On the near-circular aperture, pointed at the apical end. Orna-

interconnected consists of about 9 which older whorls, 6 closely set rows of ment spiral ridges, are most

around and continue to the tubercles occur, crossed by nearly equally strong radial pronounced the umbilicus striae. The last whorl has an angular, but not keeled, shell's periphery. periphery. Above the periphery, 7-10 close-set rows of Discussion — This species is extremely rare in the

intercon- Petaloconchus bed and in the Oorderen Member. tubercles occur; the tubercles are only weakly Only

and nected. The spiral rows of tubercles are nearly as wide as few specimens have been collected (NNM, A. Janse the intercostal areas. Between these spiral rows, fine F. van Nieulande Collections). It has not been previously

which less recorded from the Pliocene. In the British radial lines are present, become more or Belgian

Modern records of this obsolete near the periphery. Eleven continuous spiral ribs Pliocene, it was found at St Erth. without tubercles are seen, on the shell base, below the species are known from Spain to Norway, where,

radial lines in between. Graham and Waren it periphery. They are joined by according to (1988) (1991, 1993),

Discussion — This species differs from G. obconica f. occurs mostly in deep waters (90-2,400 mm). obconica in having coarser tubercles, which form discon- The ornament of the Kallo specimens falls within the tinuous spirals above the periphery; in addition, the new wide range of variation characterising the species, as species has fewer spirals. Gibbula obconica forma illustrated by Waren (1993). nehalenniae has a better-developed and finer spiral, non-

G. tuberculate ornament. The new species differs from beetsi in having less rounded whorls, less deeply incised Genus Dikoleps Hoisaeter, 1968

and intercostal areas, more numerous spirals coarser tubercles. Gibbula (Colliculus) woodi (Harmer, 1923) is Dikoleps pusilla (Jeffreys, 1847)

PI. 6, 3 nearly smooth, flat-sided and has a very shallow suture. Fig.

Of ’Trochus (Calliostoma) incertus’ Harmer, 1923 but a

1847 17. single fragment is known from the St Erth Beds; it shows Margarita pusilla Jeffreys, p.

but is with the umbilicus 1923 Cyclostrema nitens — Harmer, 755, pi. a comparable ornament, larger, (Philippi) p. 60, fig. 19. apparently absent, the suture probably shallow, and with

1984 Dikoleps pusilla (Jeffreys, 1847)— van Aartsen el flat-sided whorls. So long as no better-preserved is 39. al., p. 12, fig. dubium. available, this name is better treated as a nomen

1988 Skenea nitens (Philippi, 1844) — Graham, p. 136, Remarks — The present species is confined to the fig. 46. Petaloconchus bed (Kattendijk Formation) at Kallo, in 1991 Dikoleps pusilla (Jeffreys, 1847) — Waren, p. 56, which it is much rarer than G. obconica forma obconica. pi. 2, fig. 2.

1993 Dikoleps pusilla (Jeffreys, 1847)— Waren, p. 179,

fig. 12f.

Family Skeneidae Clark, 1851 1994 Dikoleps pusilla (Jeffreys, 1847) — Gianuz-

355. Genus Skenea Fleming, 1825 zi-Savelli et al., p. 106, fig.

Subgenus Lissospira Bush, 1897

Dimensions — Height 1 mm, width 1 mm.

Description — Minute, turbiniform shell, with relatively

The umbilicus is and Skenea (Lissospira) basistriata (Jeffreys, 1877) low spire and tumid whorls. narrow

closed extension of the inner of the PI. 6, Fig. 2 partially by an lip The has basal and aperture. outer apertural lip a a

17. Surface smooth, for lines. 1877 Margarita basistriata Jeffreys, p. peripheral bay. except growth

1923 Cyclostrema basistriatum, Jeffreys, MS. — Harmer, Discussion — This species differs from the previous in

17. p. 753, pi. 60, fig. lacking ornament, in having the umbilicus partially closed

1988 Skenea basistriata 1877) — Graham, is the (Jeffreys, p and a lower spire. It too new for Belgian Pliocene, 138, fig. 47. having been first discovered at Kallo by Y. Butaye,

basistriata — 1991 Skenea (Jeffreys, 1877) Waren, p. 64, where it is extremely rare in the Atrina bed (Oorderen

fig. 5a, b, e, f, h; 7a, c. Member). Other records include the Pliocene of St Erth.

1993 Skenea basistriata — (Jeffreys, 1877) Waren, p. rather According to Graham (1988) this is a species of 176, fig. 16. shallow water. Most modern authors, e.g. Waren (1991,

1993) and van Aartsen et al. (1984), consider Dikoleps

Dimensions — width Atlantic-Mediterranean distinct from Height 0,8 mm, 0,8 mm. pusilla, an species,

Description — Minute, turbiniformshell, with relatively D. nitens (Philippi, 1844), from the Mediterranean. The

high spire, tumid whorls, deep open umbilicus and oval, latter may be distinguished in showing ornament on the 71

lower 2: 1-251. part of the shell, around the umbilicus. montese, Memorie,

1918. Essais de Cossmann, M., Paleoconchologie comparee.

Onzieme Livraison. 388 11 Paris (The author), pp., pis.

1926. The nomenclature of certain British mollusca ACKNOWLEDGEMENTS Dean, J.D.,

and description of a new species of Emarginula. — Journal

of Conchology, 18(1): 21-24, pi. 1. Several people, amongst whom Mrs Y. Butaye, Messrs Dewael, N., 1853. Observations sur les formationstertiaires des K. Hoedemakers, E. Huysmans and A. Ratinckx, assisted environs d'Anvers. — Bulletin de TAcademie royale de la field work. members of the during Many 'Belgische Belgique, (2)20(1): 1-36.

and the Vereniging voor Paleontologie' 'Werkgroep voor Dumont, A., 1839. Rapport sur les travaux de la Carte

Tertiaire en Kwartaire Geologie', who collected material geologique pendant l'annee 1839. — Bulletin de

at Kallo, made their specimens available for study. I wish l'Academie royale de la Belgique, 6(2): 464-485.

J., 1828. A of British animals, to thank in particular Mrs I. Butaye, Dr P. Gigase, and Fleming, history exhibiting the

characters and of Messrs A. Janse, H. Keukelaar, K. Peeters, D. Lauwers, descriptive systematical arrangement

and of genera species quadrupeds, birds, reptiles, fishes, F. van Nieulande and G. Willems. Material collected by molluscs, and Radiata of the United Kingdom. Edinburgh, Mr A.W. Janssen, housed in the collections of the xxiii 565 + pp. Nationaal Natuurhistorisch Museum (Leiden, The Nether- Gaemers, P.A.M., 1975a. Enkele paleo-ecologische lands) was also studied. The excellent photographs and opmerkingen over de Pliocene afzettingen in de tunnelput photo-micrographs were prepared by Messrs M. nabij Kallo, Belgie, provincie Oost Vlaanderen. Deel 1. — Wagenaar and W. Cillis (Koninklijk Belgisch Instituut Mededelingen van de Werkgroep voor Tertiaire en

voor and Natuurwetenschappen), respectively, developed Kwartaire Geologie, 12(1): 25-37, pis 1-3.

by Mr W. Miseur of the same institute. Dr A.V. Dhondt Gaemers, P.A.M., 1975b. Enkele paleo-ecologische

and Dr K. Wouters allowed me to use the research opmerkingen over de Pliocene afzettingen in de tunnelput

facilities of that institute. Last but not least, Mr J. nabij Kallo, Belgie, provincie Oost Vlaanderen. Deel 2. —

van de voor Tertiaire Christiaens provided data on some of the fissurellid Mededelingen Werkgroep en

Kwartaire species. Geologie, 12(2): 43-49. Gaemers, P.A.M., 1983. New otoliths from the Syltian (late

Miocene) of the Morsum Cliff, Island of Sylt (Federal

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Professional Paper, 272: 1-115. 15 May 1995. 74

PLATE 1

1. and Fig. Emarginulapunctura Wood, 1848, Kallo (Vrasenedok), Kattendijk Formation (Petaloconchus bed), x 14,5 (a) x 17,5 (b). KBIN collections,

no. IRScNB IST 5872.

Fig. 2. Emarginula rosea Bell, 1824, Kallo (Vrasenedok), Kattendijk Formation ( Petaloconchus bed), x 14,8 (a) and x 15,5 (b). KBIN collections,

no. IRScNB IST 5873.

Fig. J. Kallo Formation and 3. Emarginula fissura forma reticulata Sowerby, 1813, (Vrasenedok), Lillo (Oorderen Member, Atrina level), x 8,2 (a)

Collection. x 5,7 (b). Marquet 75\1

PLATE 1 76

PLATE 2

1. Diodora Kallo 2,2 Fig. graeca (Linné, 1758), (Vrasenedok), Kattendijk Formation, x 1,9 (a), x (b) and x 1,3 (c). Marquet

Collection.

Fig. 2. Emarginula crassa crassa J. Sowerby, 1813, Kallo (Vrasenedok), Lillo Formation (Oorderen Member, Atrina level), x 0,8 (a)

and x 0,72 (b). Marquet Collection.

Fig. 3. Emarginula crassa crassalta Wood, 1874, Kallo (Vrasenedok), Kattendijk Formation (Petaloconchus bed), x 2,5 (a) and x 3,2

(b). Marquet Collection.

Fig. 4. Anatoma crispata (Fleming, 1828), Kallo (Vrasenedok), Kattendijk Formation ( Petaloconchus bed), x 23,5. KBIN collections,

no. IRScNB IST 5874.

5. Fig. Lepeta (Lepeta) scaldensis van Regteren Altena, 1954, Kallo (Verrebroekdok), Lillo Formation (Oorderen Member, Atrina

level), x 3,8 (a) and x 3,8 (b). Marquet Collection. 77\2

PLATE 2 78

PLATE 3

Fig. 1. Solariella maculata Wood, 1842, Kallo (Vrasenedok), Kattendijk Formation (Similipecten bed), x 5,4 (a) and x 6,4 (b). Marquet

Collection.

Fig. 2. Calliostoma (C.) zizyphinum (Linné, 1758), Kallo (Vrasenedok), Kattendijk Formation, x 2,1 (a), x 1,2 (b), x 1 (c) and x 1,2

(d). Marquet Collection.

Fig. 3. Calliostoma (C.) simile (J. Sowerby, 1816), Kallo (Vrasenedok), Lillo Formation (Oorderen Member, Atrina level), x 1,4 (a),

1,4 Collection; f Kallo Lillo Formation x (b), x 1,5 (c) and x 1,9 (d). Marquet e, - juvenile specimen, (Vrasenedok), (Oorderen

Member, Cultellus level), x 120 and x 60, respectively. KBIN collections, no. IRScNB IST 5875.

Fig. 4. Margarites (Margarites) trochoides (Wood, 1842), Kallo (tunnel), Kattendijk Formation, x 12,2. Van Nieulande Collection. 79\3

PLATE 3 80

PLATE 4

Fig. 1. Calliostoma (C.) aff. noduliferens (Wood, 1872), Kallo (Zeesluis), Lillo Formation (Oorderen Member), x 8,2 (a) and x 9,1

(b). KBIN collections, no. IRScNB IST 5876.

Fig. 2. Calliostoma (C.) kickxii (Nyst, 1835), Kallo (tunnel), Lillo Formation (Oorderen Member, basal crag), x 5 (a), x 4,4 (b) and

x 6,2 (c). Van Nieulande Collection.

Fig. 3. Calliostoma (Eucasta) occidental e(Mighels & Adams, 1842), Kallo (Vrasenedok), Kattendijk Formation (Similipecten bed),

x 2,5 (a, b). Marquet Collection; c - same locality and level, x 2,5. Marquet Collection; d, e - juvenile specimen, same locality

and level, x 16 and x 60, respectively. KBIN collections, no. IRScNB IST 5877.

Fig. 4. Gibbula (Gibbula) solarium (Nyst, 1835), Antwerp (Zevende Havendok), Lillo Formation (Kruisschans Member), x 2,6 (a),

x 2,7 (b) and x 2,3 (c). Marquet Collection. 81\4

PLATE 4 82

PLATE 5

Gibbula Fig. 1. (Colliculus) beetsi van Regteren Altena, 1954, Kallo (Verrebroekdok), Lillo Formation (Oorderen Member, Atrina

level), x 8 (a, b) and x 7,5 (c). Marquet Collection.

2. Gibbula obconica Lillo Formation Fig. (Colliculus) forma nehalenniae van Regteren Altena, 1954, Kallo (Verrebroekdok),

(Oorderen Member, Atrina level), x 6 (a) and x 35 (b). KBIN collections, no. IRScNB IST 5878; c - Kallo (Vrasenedok), Lillo

Formation (Oorderen Member, Atrina level), x 10,8. Marquet Collection.

Fig. 3. Gibbula (Colliculus) obconica forma obconica (Wood, 1842), Kallo (Vrasenedok), Kattendijk Formation (Petaloconchus bed),

x 8. KBIN collections, no. IRScNB IST 5879.

Fig. 4. Gibbula (Colliculus) crassistriata (Bell in Wood, 1882), Kallo (Verrebroekdok), Lillo Formation (Oorderen Member,Atrina

level), x 9 (a), x 8 (b) and x 30 (c). KBIN collections, no. IRScNB IST 5880.

5. Kallo Fig. Gibbula (Colliculus) petala n. sp., (Vrasenedok), Kattendijk Formation (Petaloconchus bed), x 8,7 (a), x 8,9 (b) and x

35 (c). KBIN collections, no. IRScNB IST 5881 (holotype). 83\5

PLATE 5 84

PLATE 6

Fig. 1. Gibbula (Steromphala) octosulcata (Nyst, 1835), Kallo (Verrebroekdok), Lillo Formation (Oorderen Member, Atrina level),

x 4,8 (a), x 5,4 (b) and x 5,3 (c). Marquet Collection.

Fig. 2. Skenea (Lissospira) basistriata (Jeffreys, 1877), Kallo (Vrasenedok), Kattendijk Formation (Petaloconchus bed), x 100 and x

84, respectively. KBIN collections, no. IRScNB IST 5882.

Fig. 3. Dikoleps pusilla (Jeffreys, 1847), Kallo (Verrebroekdok), Lillo Formation (Oorderen Member, Atrina level), x 53, x 55, and

58, x respectively. KBIN collections, no. IRScNB IST 5883. 85\6

PLATE 6