LATE CRETACEOUS-EARLY TERTIARY ECHINOIDS 



125 



Fig. 33 Camera lucida drawing of plating in Isaster aqiiilanicus (de 

 Grateloup, 1836) from the late Thanetian of Casas de Oraien (Navarra); 

 BMNH EE6202, oral surface. Scale bar = 5 mm. 



Genus HEMI ASTER Agassiz. in Agassiz & Desor, 1847 



Diagnosis. Apical disc ethmophract. Anterior sulcus weak or 

 absent. 



Hemiaster prunella (L&maick, 1816) 



PI. 9, figs ll-14;Fig. 35b, c, e 



1816 Spatangus prunella Lamarck: 33. 



1855 Hemiaster prunella Lamarck; d'Orbigny: 242. pi. 881. 



1856 Hemiaster prunella ]^axmrck\T>e?,ov: 122. 

 1927 Hemiaster prunella (Lamarck); Lambert: 50. 



1973 Hemiaster (Bolbaster) batalleriLambtn; Radig: 6l.pl. 10. 



figs 4-7. 

 1992 Hemiaster (Bolbaster) gr. prunella (Lamarck); Gallemf: 



347. 350. 

 1996 Hemiaster (Bolbaster) prunella (Lamarck); Wilmsen etal.: 



354. 



Diagnosis. Test up to about 10 mm in length; almost as wide as 

 long; subglobular with weakly domed upper surface; tallest point 

 more or less coincidental with the apical system. In profile, the 

 posterior face is more or less vertical or slopes slightly outwards. 

 Apical disc ethmolytic with four gonopores. Anterior ambulacrum 

 slightly sunken adapically. but becoming flush towards the ambitus; 

 pore-pairs strongly oblique. Anterior petals rather narrow, diverging 

 at ca. 110-120°. Posterior petals about half the length of the anterior 

 petals; not strongly bowed. Peripetalous fasciole oval without inden- 

 tation behind anterior petals. Periproct high on posterior face. 

 Peristome small, kidney-shaped with prominent rim. Labral plate 

 elongate; about half the length of the succeeding sternal plates. 



Material studied. BMNH EE4401-02, EE6240-49. EE6252- 

 6 1 , MOB 37476, 37503, 375 15-1 6, 375 1 8, 37524, 37529, 37534-36, 

 37538-40, 37547, 37558-59, 37567. 



Fig. 34 Camera lucida drawings of plating in Isaster aquitanicus (de 

 Grateloup, 1836) from the late Thanetian of Casas de Oraien (Navarra); 

 a, BMNH EE6203 apical disc; b, BMNH EE6069 apical disc. Scale 

 bars: a = 5 mm; b = 1 mm. 



Fig. 35 Camera lucida drawings of plating in Hemiaster species, a. d. H. 

 koninckamts d'Orbigny. 1855: a. BMNH EE6250. Maastrichtian, coast 

 west of Cabo Mayor (Santander, Cantabria); apical surface: d. BMNH 

 6238. Maastrichtian, Olazagutia Pass; lateral profile: b, c, e, H. prunella 

 (Lamarck. 1816): b. MGB 37534. apical surface: c. BMNH EE6252. 

 apical disc: e. BMNH El 1093. lateral: b and c from the Maastrichtian of 

 the coast west of Cabo Mayor (Santander, Cantabria); e from the 

 Maastrichtian Maastricht Formation of the Maastricht district. The 

 Netherlands. Scale bars: a-c = 1 mm; d.e = 5 mm. 



