A NEW SNAKE FROM ST LUCIA 



foramen for the maxillary nerve which emerges on the 

 underside anteriorly. 



For sample specimens the skin on the side of the neck was 

 turned forwards to expose the superficial jaw muscles and 

 ligaments and the labial glands. The most superficial muscle, 

 which is easily damaged, is the constrictor colli (Haas, 1973). 

 In the outgroup this is a thin sheet of muscle which passes 

 from about the level of the head of the quadrate backwards 

 and downwards over the jaw articulation to insert on the skin 

 of the throat. In the species of Clelia examined the muscle 

 follows a similar course, the anterior portion has a diffuse 

 origin on the surface of the adductor externus profundus 

 muscle. The posterior portion arises on the head of the 

 quadrate; this is inferred derived (Fig. 4). 



The cervico-mandibularis muscle arises from the back of 

 the neck and passes downwards and forwards to insert on the 

 articular head of the quadrate (Fig. 4). This appears to be a 

 primitive condition. From the articular head of the quadrate 

 arises a ligament which passes forwards and divides. The 

 lateral, labial portion inserts on the posterior supralabial 

 scales and onto the capsule of Duvernoy's gland. It peels off 

 the supralabial scales rather more easily than is usual in 

 snakes; this is thought to be derived. The mesial, maxillary 

 ligament passes forwards to insert on the posterior lateral 

 corner of the maxilla. 



undifferentiated vertebral scale row, no left lung and a short 

 trachea extending no more than five ventral scale units 

 beyond the tip of the ventricle. Distinguished from rustica 

 and bicolor by absence of a left lung. Distinguished from 

 clelia, equatoriana and scytalina by the undifferentiated verte- 

 bral scale-row and short trachea. Further distinguished from 

 clelia by 17 scale-rows from neck to vent. 



Holotype: BMNH 89.8.14.25, male, St Lucia, West Indies, 

 collected by G.A. Ramage, presented by West Indies Explo- 

 ration Committee; snout-vent c.112 cms, tail 32 cms with 

 extreme tip missing. 



Paratype: MNHP 7598, male, St Lucia; snout-vent 

 c.116 cms, tail 29+ cms with tip missing. 



Referred specimens: BMNH 89.8.14.12, female, 'Domin- 

 ica', West Indies, collected by G.A. Ramage, presented by 

 West Indies Exploration Committee, snout-vent 138 cms, tail 

 27.6 cms. 



BMNH 1988.717, female, 'Demerara', presented by Capt 

 E. Sabine, R.E., snout-vent 117 cms, much of the tail is 

 missing. 



The other species of Clelia are widely distributed on the 

 South and Central American mainland and a few offshore 

 islands (Bailey, 1970). The name is taken from the Latin 

 errabundus = wandering, in reference to the occurence of 

 the new form well outside the range of its mainland relatives. 



Fig. 1. Clelia errabunda sp. nov., type BMNH 89.8.14.25. A, lateral view of head (reversed on account of distortion of right side of head); 

 B, dorsal view of head. 



Mucous supralabial glands extend along the margin of the 

 upper lip from the corner of the mouth to the snout. There 

 are similar glands along the margin of the lower jaw. Mesial 

 to the three posterior supralabial scales lies the Duvernoy's 

 (venom) gland (Fig. 4). 



At the level of the corner of the mouth, mesial to the 

 maxillary ligament, is the organ termed anterior temporal 

 gland by Smith & Bellairs (1947) and rictal gland by McDow- 

 ell (1986). It is found in all of the species examined; it is 

 usually visible mesial to the posterior end of the Duvernoy's 

 gland (Fig. 4). 



RESULTS 



Clelia errabunda sp. nov. 



Diagnosis. A species of Clelia with uniform dark grey adult 

 colouration of the upperside of the head, trunk and tail, 

 extending to the lateral margins of the ventral scales, an 



The type has two preocular scales on one side, seen in no 

 other specimen of Clelia. All have two anterior and three 

 posterior temporals. The lower anterior temporal scale meets 

 a postocular in the type only. The 'Demerara' specimen has 

 three anterior supralabial scales on the left-hand side, seen 

 elsewhere only in C. bicolor. All have five anterior infralabial 

 scales and three posterior. The anterior genials are little, if at 

 all, larger than the posterior. The four specimens have 

 tubercles but no pits on the head, as in other Clelia and 

 Pseudoboa. The number of frontal and parietal tubercles is 

 high. Most of the trunk scales bear paired apical pits, as is 

 usual in Clelia, and a moderate number of tubercles (Table 2, 

 see Appendix). 



The island specimens have 14 anterior maxillary teeth (on 

 the left), which is higher than for clelia and equatoriana 

 (Table 3, see Appendix); the 'Demerara' specimen has 13/12. 

 The ventral scale counts are high for Clelia, but not extreme. 

 The subcaudal scales are entirely paired, save that the last 

 one is single in the 'Dominica' specimen. Apart from the 

 difference of sex the three island specimens are very similar. 



