BRITISH AVONIAN CONODONT FAUNAS 131 
is thus the senior and correct name for the genus, and Cladognathodus Rexroad & 
Collinson 1961 is a junior synonym. We are grateful to Dr. Curt Teichert for 
pointing this out to us (see also Mound 1965). 
Kladognathus clarensis Collinson & Druce 
Plate 23, figs. Ia—2b 
Kladognathus clarensis Collinson & Druce (in press). 
MATERIAL. 3 specimens: figured, X 195, X 196. 
Rance. North Crop 3D 10-3D 23. 
DescriPTIon. In lateral view this species resembles the genus Metalonchodina. 
Its most striking feature is the greatly enlarged, laterally compressed denticle which 
comprises most of the posterior bar. This is inclined posteriorly but the curvature 
may be more or less continuous, or it may be chiefly confined to the base, with the 
upper part of the denticle having straight anterior and posterior edges. The inner 
lateral face tends to be rather more convex than the outer. The posterior aboral 
termination is more or less sharply pointed. 
The fang is relatively small in comparison with the posterior denticle. It is 
slender, posteriorly continuously recurved, and has sharp anterior and posterior 
edges. The anterior bar consists of 1 to 3 denticles and the anterior aboral margin is 
spatulate in form with the anterior aboral angle being rounded. In multidenticulate 
anterior bars the most anterior denticles tend to be more or less erect, but the more 
posterior ones tend to be recurved. 
The lateral process is short and bears at least one oral denticle. The whole unit 
tends to be laterally deflected, the outer lateral face tending to be concave. The 
aboral surface below the main denticle on the posterior bar is broad, and has a 
conspicuous flattened basal surface. It consists essentially of an inverted basal 
cavity, with a median groove which is continued along the anterior bar. All of the 
three present specimens have a short, laterally compressed, inconspicuous denticle 
lying between the fang and the main denticle of the posterior bar. 
Posterior 
Fang 
ae 
Anterior bor Posterior denticle 
she 
Inner lateral process 
Posterior bor 
Aboral margin 
Fic. 26. Kladognathus sp. showing morphological terms used in the text. 
