LATE CRETACEOUS-EARLY TERTIARY ECHINOIDS 



89 



& Keller, 1994) have suggested that faunas living at high latitudes 

 may have suffered less extinction. So, how does the pattern of 

 extinction and survival in Spain compare with that seen at other 

 latitudes? 



At the end Cretaceous northern Spain lay at approximately 35°N 

 palaeolatitude (based on the palaeogeographic reconstruction of 

 Scotese et ai, 1989). Two other late Cretaceous echinoid faunas, 

 lying more or less at the same palaeolongitude, have been thoroughly 

 documented from western Europe - from the Danish basin and from 

 the Benelux area. The Maastrichtian of the Danish basin is composed 

 of mid-shelf chalks best exposed on the islands of Zealand, Den- 

 mark, and Rtigen, North Germany. Both lay at approximately 48°N 

 palaeolatitude. In this basin changes in lithofacies do occur across 

 the K-T boundary, but are much less pronounced than in any other 

 part of Europe. As a result chalk facies occur in both the Maastrichtian 

 and Palaeocene. Thirty-six Maastrichtian echinoid species are known, 

 of which ten (28%) survive into the Danian. At generic level 1 8 of the 

 24 Maastrictian genera found in Denmark (75%) have a post- 

 Maastrichtian record. 



The Maastrichtian of the Benelux region includes the type 

 Maastrichtian from the Maastricht district and the richly fossiliferous 

 Ciply deposits. This region lay at approximately 45°N palaeolatitude. 

 The Early Maastrichtian is represented by mid-shelf chalks and 

 shale-limestone facies while the Late Maastrichtian is predomi- 

 nantly composed of shallower carbonate platform facies. The Danian 

 echinoids from the Guelhem Formation are rather unusual, being in 

 a calcarenitic chalk facies, but dominated by distinctly shallow- 

 water species. No Palaeocene facies comparable to the bioclastic 

 limestones of the Maastricht Formation are found in this region. 

 There are 54 Maastrichtian echinoid species recorded from this 

 region (Smith & Jeffery, in press; Appendix), of which 1 1 continue 

 directly into the Danian (20%). At generic level 28 of the 38 genera 

 have a post-Maastrichtian record (74%). 



If we include the Maastrichtian faunas of the eastern Pyrenees and 

 the Alicante- Valencia basin with those described in this paper we 

 have a total of 59 species and 43 genera from shallow, mid-shelf and 

 deep-water settings at approximately 35° palaeolatitude. Sixteen of 

 the 59 species (27%) and 27 of the 43 genera (63%) have a post- 

 Maastrichtian record. 



Extinction levels at all three palaeolatitudes are very similar, and 

 survivorship at palaeolatitudes of 35° and 45^8° are not signifi- 

 cantly different (%- test p > 0.90) at both generic and species level. 

 Therefore, across Europe there was no strong latitudinal gradient to 

 end Cretaceous extinctions in echinoids. 



Africa or Spain (e.g., Gitolawpas. Circopeltis, Thylecliitnis, Linthia) 

 appear for the first time in the Guelhem Member. Conversely, there 

 are also a large number of genera, present in the Maastrichtian of the 

 Maastricht area, that are found only outside that area in the 

 Palaeocene. Clearly there was a major shift in geographical ranges at 

 the end Cretaceous. 



Faunal immigration and emigration at the end of the Cretaceous is 

 not restricted to the Benelux region. The Appendix gives a break- 

 down of the composition of the surviving Maastrichtian and 

 Palaeocene genera in terms of their geographic origin. Only approxi- 

 mately one-third of taxa remained resident during this period, while 

 significant immigration and emigration from all three regions dis- 

 cussed above took place (Table 2). The resulting pattern of high 

 levels of local species extinction accompanied by marked shifts in 

 generic range appears to characterize this time interval. 



Table 2 Survivorship and migration data on western European echinoid 

 genera at the end Cretaceous. See text for explanation. 



Generic 

 survival 



Palaeocene 

 immigrants 



Resident Maastrichtian 

 emigrants 



Denmark basin 75% 

 Benelux area 74% 

 Spain 63% 



9 



7 

 15 



10 8 

 13 15 

 12 15 





SYSTEMATIC DESCRIPTIONS (A.B. Smith, J. 

 Gallemi and C.H. Jeffery) 



Order CIDAROIDA Claus, 1880 



Diagnosis. Regular echinoids with simple ambulacral plafing and 

 a single large primary tubercle on each interambulacral plate. 



Family PSYCHOCIDARIDAE Ikeda, 1936 

 Genus TYLOCIDARIS Pomel, 1883 



Diagnosis. Primary tubercles imperforate, non-crenulate. 

 Peristomial membrane contains ambulacral plates only. Primary 



spines clavate. 



Changes in faunal range. Maastrichtian genera that survive into 

 the Palaeocene either continued in the same region or became locally 

 extinct but survived elsewhere. The relative proportion of resident to 

 emigrating lineages in an area reflects the degree to which local 

 facies have been disrupted. If there is a significant change in facies 

 then one might expect to see a high degree of local extinction at 

 species level, but with many of the lineages (represented by conge- 

 neric species) continuing into the Palaeocene. Conversely, Palaeocene 

 genera in each region can either represent resident lineages that have 

 survived in the area, or immigrant lineages that appear in the area for 

 the first time. 



The fauna of the early Danian Geulhem Member of the Maastricht 

 district described by Van der Ham (1988) is a striking example of 

 how echinoid faunal ranges underwent a major reorganization after 

 the K-T event. The Geulhem Member has just as diverse an echinoid 

 fauna as any member of the Maastrichtian Maastricht Formation, but 

 there are almost no species and very few genera in common between 

 the two. A number of taxa known from the Maastrichtian of North 



Tylocidaris (Sardocidaris) ramondi (Leymerie, 1851) 



PI. l,fig. 1 



1851 Cidaris ramondi Leymerie: 192, pi. 9, fig. 12 a, b, ?1 Ic. d. 

 1857 Cidaris ramondi Leymerie; Desor: 16, pi. 6, fig. 13. 

 1862a Cidaris ramondi Leymerie; Cotteau: 315 (pars), pi. 1076, 



figs 1-8, 10-12, 14-17. 

 1910 7\'/oc/Wam ramon^/ (Leymerie); Lambert & Thiery: 156. 



Diagnosis. Test large with more than seven interambulacral plates 

 in a column (as opposed to the five typical of Tylocidaris 

 (Tylocidaris)). Ambulacra broad, with contiguous outer series of 

 primary tubercles and inner series of three or four smaller granules in 

 two irregular rows on each plate. Spines large, up to 25 mm in length, 

 with a highly characteristic bulbous shaft, short neck and sharp 

 transition to shaft. Shaft widest one-quarter of the distance above the 

 base; width 50-60% of length. Distal end of spine bluntly pointed. 

 Sun'ace densely covered in coarse granules that are more or less 

 contiguous, leaving no intergranular spaces. Granules are generally 



