30 
B 
Fig. 19 Baryonyx walkeri, holotype, BMNH R9951; scanning electron 
micrographs of tooth crown in Fig. 18C. A, denticles on the mesial 
carina and the granular texture of the enamel, x 30; B, higher 
magnification of four denticles from the centre of row in A, x 150. 
largest of those in the preserved portion (bearing only the first 7-8 
alveoli) is no. 3, from which they diminish fairly regularly in both 
directions. In the dentary, by contrast, the size of the alveoli is 
generally much more regular, nos 5—26 forming a straight series of 
almost uniform diameter; 1-4, however, are appreciably larger, 
producing a slight swelling corresponding in position to the spatu- 
A.J. CHARIG AND A.C. MILNER 
late tip of the upper jaw but much less marked; 27—32 diminish | 
regularly. 
Vertebral column 
CERVICAL REGION (Figs 20, 21). Five cervical vertebrae are pre- | 
served fairly complete, including the axis. Also preserved are the 
atlantal pleurocentrum (odontoid), the right atlantal neurapophysis, | 
the axial intercentrum, and one cervical rib. The vertebrae were not | 
found in articulation, so they are ordered according to the various 
morphological trends that they display. If it be assumed that the total \ 
cervical count was the usual theropod number, nine, then the verte- | 
brae preserved, in addition to the axis (Ce2), are likely to be Ce3, 
Ce5, Ce6 and Ce8. Their most important dimensions, together with 
those of the dorsal vertebrae, are given in Table | below. 
Table 1 Dimensions of the cervical, dorsal and proximal caudal 
vertebrae (all measurements are in mm) 
A pee CDs OE "Geeta es OK WE Mi 
Soa52'e 130 gee = eee a 
Ce3 55e 45 70 65 81 126 90 101 — = = = 
Ce5 Oil 3) 0 Stele 74h Ibi IS) ily = - - = 
Ce6 67e 44e 84 65 95 179 111 110 — - - = 
Ce8 84e 62 95 66e 120 204 99 98 —- Saree BS 
= 123: ¢8iieeel6: 50427, 
D2 103 85 100 78 108 109 115 110 100 14 44 25 
D3 SSemOsm OP, Wp Sky tei) IIS! 7/8) 2s) 
DS G3} 12 Se Ww 92) 1095 1625 162 O62 8 lO? eel 
D6 88 73 90e 88 88 117 62 61 134 41 nfr 18 
D7 = 129 70 63 140 48 nfr 20 
DS © 822 74 70 84 93 - 22 Sis 22 
Didum= 140.66 — ° Se ee 
D11 80 81 tbd thd 105 161 73 61 197 80 nfr 18 
D13 88 96 100 98e 108 =-~-— — = 
D14 104e 96 114 94e 110 184 69 68 2011 86 nfr 19 
AS Bae DD” JERE 
Cay S97 I 110) SARs: 
CaB” SI 99N 92 10 7e 4432 
CaC 4 140 — 
A, transverse diameter of anterior face of centrum; B, vertical diameter of 
anterior face of centrum; C, transverse diameter of posterior face of 
centrum; D, vertical diameter of posterior face of centrum; E,length of 
centrum below, rim to rim; F, transverse width of centrum at narrowest 
point (i.e. ‘waist’) (for proximal caudals only); G, length of neural arch 
(front of prezygapophysis to back of postzygapophysis; mean of both sides 
where both are available); H, total width across prezygapophyses; I, total 
width across postzygapophyses; J, height of neural spine (measured from 
roof of neural canal at anterior end); K, length of neural spine parallel to 
body axis (measured from point of divergence of postzygapophyses); L, 
length of neural spine plus rugosities; M, thickness of neural spine 
(measured at point of divergence of postzygapophyses); e, estimated; i, 
incomplete; idc, ignoring deep concavity in upper margin; nfr, no further 
rugosities; tbd, too badly damaged. 
The cervical vertebrae themselves have the following general} 
characters: 
The neck as a whole tapers from the back towards the front. The: 
centrum of each vertebra is significantly shorter than those behind} 
it. The transverse diameter of the deeply concave posterior face of 
