42 



J. WATSON, S.J. LYDON & N.A. HARRISON 



Fig. 9 A-F Ginkgoites weatherwaxiae sp. nov. All light micrographs of petiole specimen V.64540. A, fragment of petiole, dissected and opened out, 

 showing large round bite-mark and resin bodies, x 15; B, large, spindle-.shaped resin body present in petiole, seen also in upper part of Fig. A, x 50: C, 

 cuticle of upper surface, showing ordinary epidermal cells in rows and distribution of stomata, x 125; D, cuticle of lower surface, showing elongate 

 ordinary epidermal cells and stomatal distribution, x 125: E, single elongate, longitudinally aligned, stoma on upper surface, x 500: F, inconspicuous 

 stoma on lower surface, x 500. 



(Fig. 7E) but the extreme tip is often broken or missing. This feature 

 is commonly found in fossil conifers and its significance has been 

 speculated upon and discussed by various authors, most recently by 

 Watson & Harrison (1998) in relation to Pseudotorellia linkii which 

 is described below. 



The petiolate nature of the G. weatherwaxiae leaf is recognised 

 from the cuticle similarity in isolated specimens (Fig. 9A) with 

 typical petiole characters such as narrow, more elongate cells (Fig. 

 9C, D), low stomatal densities and small stomata (Fig. 9E, F). 

 Unfortunately, in none of the specimens is there any indication of 

 how the top of a petiole widens and passes into the basal part of the 

 leaf lamina. The petiole in Fig. 9A, and the leaf segment in Fig. 7G 

 are particularly interesting in showing what appears to be animal 

 (presumably arthropod) damage. The hole in the cuticle in Fig.7G, H 

 shows clear evidence of reaction to the damage and signs of repair 

 around the edges of the damage (Fig. 7H) which involves both 



surfaces of the leaf. Figs 12D, 14D show what is possibly post- 

 mortem insect damage in a Ginkgoites leaf and are discussed further 

 below. In recent years study of such animal traces in fossil plants 

 have considerably increased with a view to gaining important infor- 

 mation about the evolution of these relationships (Scott & Titchener 

 1999). Insects described from the English Wealden (Jarzembowski 

 1995) include hemipterans, or bugs, which have mouthparts modi- 

 fied into a tubular beak for piercing and sucking. Despite the general 

 resistance of Ginkgo biloba to pests, infestation by homopterous 

 hemipterans is well known (Honda 1997) and the presence in the 

 Lower Weald Clay (Hauterivian) of Penaphis woollardi Jarzem- 

 bowski, thought to belong to an extant lineage of gymnosperm- 

 feeding aphids (Jarzembowski 1989), is an intriguing possibility. 

 The sizes of the bites or punctures in these leaves, at up to 1 mm (Figs 

 9A; 12D; 14D), are somewhat large for confident attribution ta 

 aphids (Jarzembowski pers. comm. 2000) and are more likely to be 



