78 
When three toes are considered, there are eight possible combina- 
tions of the two patterns of kinking. BBB* (3), BBA* (2), BAB* (1), 
BAA, ABB, ABA* (1), AAB, AAA* (9). Five of these (asterisked) 
have already been observed in the small sample of climbing lizards 
examined; figures in parentheses indicate the number of cases 
encountered of each. 
As already noted, pattern B in toe 5 is most usual among lacertids 
in forms that climb on vegetable structures (marked#), but when 
members of other families are also considered it is clear there are 
species with fifth toes exhibiting pattern A in this situation. Overall, 
there is no obvious correlation of pattern B with climbing on 
vegetable structures in any of toes 3-5. 
The widespread occurrence of toe kinking in climbing lizards and 
its repeated evolution suggests that it confers performance advan- 
tage in this locomotory situation. However, the variety of patterns, 
including differences in the more proximal parts of toes 3—5, and the 
fact that they occur in various combinations in these toes, suggests 
that the exact arrangement of phalanges may be rather arbitrary in 
functional terms. Nonetheless, the existence of a particular pattern 
across some clades within the Lacertidae indicates that, once a 
pattern for a toe has become established, it may persist for long 
periods, even though multiple shift from pattern A to pattern B in toe 
5 has also occurred. If the pattern of kinking is more or less arbitrary 
in functional terms, shift from one to the other might sometimes 
occur after an intervening non-climbing phase when the initial 
pattern was lost, but there is no overt evidence for such interludes. 
The structure of the manus 
As with the pes, the lacertid manus always possesses the primitive 
lizard phalangeal formula, which in this case is 2,3,4,5,3. The manus 
is also like the pes in the way the digits articulate with the metacarpals 
via ball and cup joints and in having terminal articulations that are 
tightly bound gynglymi with associated sesamoid bones. Metacar- 
pal 3 is always the longest and numbers | and 5 the shortest, the 
digits are more equal in length than those of the pes and are capable 
of being broadly spread. 
The manus in ground dwelling lacertids from open situations 
(Fig. lla, Table 3) 
In advanced members of the -Armatured clade, the manus is often 
quite small compared with the pes although this differential is less 
obvious in species from soft-sand habitats. The longest digit is 
usually number 3 or this is subequal to 4. Toes are straight or gently 
curved ventrally and are rounded in cross section. The phalanges are 
often very robust, frequently more so than in the pes, and except for 
the terminal ones, tend to be subequal within a digit. The relative 
brevity of toe 4, which has most phalanges, means that these are 
particularly short. The final phalanx of each digit and the claw that 
covers it tends to be long, shallow and curves gently downwards. 
Articulations within digits are double and, as in the pes, mesial 
flexion of the toes is restricted. 
The manus in lacertids regularly climbing on steep open surfaces 
(Figs 11b,c, Table 3) 
In forms like Lacerta oxycephala, the manus is smaller than the pes 
but comparatively much larger than in many ground dwellers. The 
longest digit is usually number 4 and digits are lateromesially 
compressed; numbers 3 and 4 are flexed downwards at the articula- 
tion of phalanges 1 and 2, and somewhat upwards at the penultimate 
articulation, as in the other digits. Phalanges are slender, the penul- 
timate ones being relatively long and slightly curved downwards; 
phalanx number 2 of digits 3 and 4 and also number 3 of the latter are 
E.N. ARNOLD 
Table 3. Characteristics of the manus in ground dwelling and climbing 
lacertids (see Fig. 11). Differences in transverse section of the digits, shape 
of phalanges, claws and articulations within digits are similar to those in 
the pes. 

Ground Climbing 
(e.g Acanthodactylus) (L. oxycephala) 
Longest digit 3, or 3 and 4 subequal 4 
Phalange 2 of digits 3 weakly strongly 
and 4 and phalanx 
3 of digit 4 shortened 
Phalange 2 of toes 3 no yes 
and 4 flexed downwards 
Digits can be very no yes 
very widely spread 
Mesial flexibility of restricted substantial 
digits 
shorter than the ones bordering them. The final phalanx of each digit 
and the claw that covers it is short deep and recurved. As in the pes, 
the main ventral tendons are offset in the regions where digits are 
flexed downwards. Articulations within the digits are simple involy- 
ing a single cup and ball arrangement and the digits can be abruptly 
flexed in the horizontal plane both mesially and laterally, especially 
in the area of the penultimate articulation. 
The manus of Holaspis guentheri (Fig. 11c) deviates consider- 
ably from that characteristic of other lacertids climbing on continuous 
open surfaces. Digits 2—5 are more subequal in length, and numbers 
3 and 4 are conjoined for the length of their first phalanx, penult- 
mate phalanges are extremely long and more curved ventrally than 
in other lacertids and phalanx 2 of toe 3 and phalanges 2 and 3 of toe 
4 are very short and flexed downwards. This degree of distinctive- 
ness in the manus of Holaspis contrasts with that of the pes which, 
although it has the features usually associated with climbing on open 
surfaces better developed than in Lacerta oxycephala, does not 
differ radically from this species in its general form. 
Characteristics of the feet in other lacertids 
The numerous primitive Palaearctic lacertids and more basal mem- 
bers of the Armatured clade that climb to a significant extent on open 
surfaces have at least less marked versions of the foot characters that 
form a syndrome in a specialised climber like L. oxycephala, 
although the foot tends to be longer. Thus, the claws are relatively 
deep, the toes compressed and kinked, and metatarsal 3 is longer 
than 4 in the pes. These features occur, for instance, in many 
‘archaeolacertas’, some Podarcis such as P. hispanica, Algyroides 
nigropunctatus and A. marchi, members of the Lacerta agilis group 
but not L. agilis itself, Gallotia, Psammodromus algirus, 
Australolacerta and most members of the Equatorial African group. 
Independent shifts to the more marked version of the syndrome are 
found in such frequent climbers as Lacerta perspicillata, 
Omanosaura and especially Holaspis. 
Forms that climb in vegetation matrixes, like Gastropholis, some 
Takydromus and Poromera, tend to have relatively weak versions of 
the climbing pattern but may also possess distinctive features for 
instance, in the latter two genera, separation between the digits may 
extend proximally between the distal parts of the metacarpals and 
metatarsals, allowing wider spread of the digits. 
The manus and pes features that characterise advanced ground- 
dwelling members of the Armatured clade have developed in other 
ground-dwelling lacertids, at least in restricted form. Thus metatar- 
sal 4 is about equal to number 3 in Lacerta agilis, Psammodromus 
hispanicus and Adolfus alleni and is longer in some Podarcis that run 
extensively on the ground, such as P. sicula and P. taurica. Digit 5 of 
