ANNALS OF THE TRANSVAAL MUSEUM

ANNALE VAN DIE TRANSVAAL-MUSEUM- <

VOL. 30 30 JUNE 1976 No. 6

THE BURROWING GECKOS OF SOUTHERN AFRICA, 5 (REPTILIA: GEKKONIDAE)

By W.D. HAACKE Transvaal lvIllseum, Pretoria

(With four Text-figures)

ABSTRACT This study deals with the entirely terrestrial genera of southern African geckos and is published in five parts in this journal. In this part the phylogenetic and taxono­ mic affinities of these genera based on pupil shape and hand and foot structure are discussed.

PHYLOGENETIC AND TAXONOMIC AFFINITIES In his classification of the Gekkonidae, Underwood (1954) placed six South African genera into the subfamily Diplodactylinae. These genera, i.e. Cho!ldrodac~ylus, Colopus, Palmatogecko, Rhoptropus, Rhoptropella and Ptmopus were supposed to share a peculiar variant of the straight vertical pupil which he called Rhoptropus-type. He notes that all of them occur in "desert or veldt" and appear to be adapted to the special conditions of South Africa. He further states that "Such a number of genera with several peculiar forms of feet in such a restricted area is somewhat surprising". At that time all except Rhoptropuswere considered to be monotypic genera. Since then two more species of Ptmopus and also the terrestrial, obviously related genus Kaokogecko have been described. In the present paper a special study has been made of the ground­ living, burrowing genera, which excludes Rhoptropus and Rhoptropella. Although it has been pointed out that the classification of the Gekkonidae according to the form of the digits (Boulenger, 1885) and the shape of the pupil (Underwood, 1954) is unsatisfactory (Stephenson, 1960; Kluge, 72

1964 and 1967) the possibilities of these characters as taxonomic indicators were reinvestigated in the genera in question and related forms.

PUPIL SHAPE According to Underwood (1954) the six diplodactyline gekkonid genera all have the same type of pupil, which he referred to as £(boptroptls­ type. Pasteur (1960) found that the edge of the pupil of Sr:mrodacrylffs mauretanictfs and fascialtls, although straight-edged in life, became wavy after preservation. As the pupil always distorts in the same way after death, he assumes that this phenomenon corresponds to a histological peculiarity of the iris of these animals. Kluge (1964: 4) found that in live material the pupil shape varied slightly under different lighting conditions, but markedly so in preserved material. He thereby proved the unreliability of the pupil as a diagnostic character and no longer recognized Underwood's subfamilial groups. Amongst the genera under discussion Rhoptropella and Ptmoptls have a straight vertical pupil while the remaining ones, excluding Rhoptroptls} which is discussed below, have pupils with lobed margins which overlap to some extent, thereby closing down to four pinholes, a shape which Underwood (1954) referred to as Gekko-type. This shows that even by Underwood's standards this group of genera is not necessarily closely related and illustrates the danger of working with an inadequate series of specimens. Preserved specimens of Rhoptroptfs were also examined for pupil shape. The so-called Rhoptroptts-type is only present in R. afer. In R. bradfteldi and R. barnardi the anterior edge is nearly straight, while the posterior edge is lobed. R. bottltoni and R. tatmiosticttls have clearly Gekko-type pupils. The variation in the pupil shape of this genus thus confirms Kluge'S (1964) findiogs regarding the unreliability of this character as a diagnostic feature for sub-familial separation.

PEDAL CHARACTERISTICS Boulenger (1885) based his classification of this group mainly on the external pedal characteristics, but Stephenson (1960) and Kluge (1967) pointed out the dangers involved in using the phalangeal formulae as an indication of relationship and phylogeny of the gekkonids. Nevertheless, phalangeal structure proved taxonomically important when splitting Crenodactyllfs from PI!Jllodacrylus and Ebenavia (Dixon & Kluge, 1964). Because of the unusual structure of the appendages of the terrestrial gekkonid genera of southern Africa a special examination of these appears to be warranted. 1. Ptenopus garrulus (TM 32705) MANUS: Phalangeal formula 2,3,4,5,3 (Fig. 1c). A small sesamoid occurs dorsal to the radiale while a large, flat sesamoid covers most of the palmar surface. The first and fifth metacarpals are shorter and thicker than the remaining ones. A prominent protuberance occurs near the proximal epiphysis of metacarpal 1. All the phalangeal articulation surfaces are rather flat and the phalanges are tightly joined indicating that only a 73

minimum of lateral movement is possible. Proximally the terminal, claw­ bearing phalanges extend over the distal condyle of the penultimate phalanges and a sesamoid occurs just behind this extension. Ventrally a sesamoid occurs below the metacarpal-phalangeal joint as well as below all the interphalangeal joints except the terminal ones of fingers two to five. Ventrally the proximal articuution surfaces of all except the terminal phalanges extend backwards. The flexor muscles, in which the above­ mentioned sesamoids are embedded, are attached to these extensions. The terminal claw-bearing phalanges have a midventral swelling to which the contractor tendon is attached (cf. Mahendra, 1941: 296). PES: Phalangeal formula 2,3,4,5,4 (Fig. 1a and b). Four small sesamoid bones, of which three lie helow the tibio-fibulare and the fourth below the cuboid, occur on the palmar surface of the tarsus. Metatarsals one to four are long and thin while five is only half as long as four. The fifth metatarsal is dub-shaped and much less hooked than in the other genera under discussion. The shape and articulations of the tarsal phalanges are similar to the situation described for those of the hand. However, the ventral, backward extension of the proximal articulation surfaces is less well developed. Large sesamoids occur ventral to the metatarsal phalan­ geal joints, while smaller to minute ones occur under the first joint of toes 2 and 5, first and second of toe 3 and first to third of toe 4. Dorsally sesamoids occur above the metatarsal-phalangeal joints as well as above the first interphalangeal joint of toe 1, the two terminal joints of toes 2 and 3 and the three terminal ones of toes 4 and 5. The claws of Ptmopus are not retractile and the fifth toe is not opposable. Furthermore the phalanges are capable of only limited lateral movement, and the digits are not widely spread but lie nearly parallel to each other. In later discussions this type of structure will be referred to as a straight­ fingered or straight-toed pattern. 2. Ptenopus carpi (TM 32332) MANUS: Phalangeal formula 2,3,4,5,3. In general similar to that de­ scribed for garrulus but with slightly thicker metacarpals, and very large sesamoids on the ventral side of the fingers, except the terminal joint of finger 1 where none is present. On the dorsal side the sesamoids are very poorly developed and in some cases are hardly discernible. PES: Phalangeal formula 2,3,4,5,4. General structure very similar to that described for garrulus but with only two sesamoids on the palmar surface below the tibio-fibulare. The sesamoids on the ventral side are much better developed than those of garrulus but those on the dorsal side are much less well developed and only a single, minute sesamoid occurs just proximally to the terminal joint on all five toes. 3. Ptenopus kochi (TM 31656) MANUS: Phalangeal formula 2,3,4,5,3. Basically identical to the struc­ ture described for garrulus but with less well developed sesamoids. No sesamoids were noticed dorsal to the terminal joint nor ventral to the third joint of digit 4. PES: Phalangeal formula 2,3,4,5,4. Similar in structure to that de­ scribed for garrulus but differing on the following points: Only two sesa- 74 moids occur ventral to the tibio-fibulare while two minute sesamoids oc­ cur next to the small first tarsal. A minute sesamoid occurs near the proxi­ mal epiphysis on the femoral side of metatarsals 2 to 4. In the toes sesa­ moid bones occur in the identical positions to those of germ/us except in toe 5 where the one ventral to the first interphalangeal joint is absent. 4. Palmatogecko rangei (TM 22830 female, TM 33199 male) MANUS: Phalangeal formula 3,3,4,5,3 (Fig. 2f). No sesam~ids occur on the ventral side of the carpus but a minute one occurs dorsolateral to the first carpal. The male specimen has an extra one dorsolateral to the distal epiphysis of the ulna. The metacarpals are spread to the extreme so that the first and fifth fingers are pointing in opposite directions. Of the meta­ carpals, which are elongate and normal, the second is the longest while the fifth is the shortest. Cartilaginous, slightly ossified, club-shaped structures occur lateral to the distal end of the metatarsals and the first phalanx of finger 4. These supports of the soft interdigital membrane have of the first phalanx of fingers 1, 2 and 3, as well as of the second phalanx of finger 4, have lateral, cartilaginous, partly ossified rod-like extensions, similar to those occurring in the toes of Kaokogecko. The terminal two phalanges of fingers 1, 2 and 5 and the terminal three phalanges of fingers 3 and 4 are bent upwards in similar fashion to those in geckos with vertically retractile claws and adhesive subdigital lamellae. No sesa­ moids were seen in the manus. The cartilaginous, rod-like reinforcements of the interdigital web are better developed in the female specimen than in the male. This may be due to age. PES: Phalangeal formula 3,3,4,5,4 (Fig. 2e). A single sesamoid occurs ventral to the first tarsaL Metatarsals 1 to 4 are thin and elongate while the fifth is so short and hooked that it no longer resembles a metatarsal but appears to be a true tarsal element. The fifth toe is completely opposable. Paraphalanges occur lateral to the distal epiphyses of metatarsals 1 to 4 and the first phalanges of toes 4 and 5. The distal epiphyses of the first phalanges of toes 1, 2 and 3 and the second phalanges of toes 3, 4 and 5 are dorso-ventrally depressed and have lateral, cartilaginous, slightly ossified, rod-like extensions which reinforce the edge of the interdigital membrane. The ~wo terminal phalanges of toes 1 to 3 and 5 and the three last phalanges of toe 4 are bent upwards in similar fashion to those of geckos with vertically retractile claws and adhesive, subdigitallamellae. Because of this similarity it is assumed that Pa/matogecko lost the sub­ digital pads as well as the claws of the fingers fairly recently and it is therefore regarded as being secondarily padless. No sesamoid bones were seen in the toes. 5. Kaokogecko vanz:;yli (TM 32807 male, TM 32810 female) MANUS: Phalangeal formula 3,3,4,5,3 (Fig. 2d). No supernumerary bones in carpus. Metacarpals long and thin, with first and second longest and fourth and fifth shortest. The first phalanges of all the fingers are subequal in length and the distal ends of those of the 1st, 2nd and espe­ cially the 5th finger are strongly flattened; the 5th has small lateral pro­ tuberances. The terminal two phalanges of fingers 1, 2 and 5 and the three terminal phalanges of fingers 3 and 4 are bent upwards as in geckos with 75 vertically retractile claws. No sesamoids were noticed in the manus of the female but in the male they are present dorsal to the metacarpal-phalangeal joint of fingers 1 to 4. The fingers are spread to the extreme so that the first and fifth point in opposite directions. PES: Phalangeal formula 3,3,4,5,4 (Fig. 2c). Metacarpals 1 to 4 are thin, long and well spread; the fifth is extremely short and hooked. The distal condyle of the fifth metatarsal has a laterally enlarged articulation surface which enables the 5th toe to be completely opposed to the other toes. The distal ends of the 1st phalanges of toes 1 to 3 are to a greater or lesser extent laterally expanded. Toes 1 and 2 have cartilaginous, curved, rod­ like extensions on botli sides of these expansions, while toe 3 has only one of these structures on the tibial side. Similar cartilaginous lateral rods occur on both sides of the flattened distal end of the 2nd phalanx of toes 3 and 4, while the fourth of toe 4 has only one on the tibial side. The second phalanx of toe 5 is quite wide and hammer-shaped but lacks the cartilaginous rods. These cartilaginous extensions, which reinforce the edge of the interdigital membrane, are not true paraphalanges as defined by Wellborn (1933) as they are attached to the bone and not free structures embedded in the membrane. The terminal two or three phalanges of all the toes are bent upwards in similar fashion to that described for the fingers. No sesamoids were noticed in the foot of the female but in that of the male they occur dorsal to the metacarpal-phalangeal joint of all toes as well as the first and second interphalangeal joint of toe 4. 6. Colopus wahlbergii (TM 29674) MANUS: Phalangeal formula 3,3,4,4,3 (Fig. 2b). No supernumerary bones in the carpus. Metacarpals well spread, elongate with second longest and fifth shortest. The corresponding phalanges of all the digits are sub­ equal in length and shape to one another. The second phalanges of fingers 3 and 4 are shorter than the penultimate ones of all fingers. The terminal two phalanges of all fingers are turned upwards as in other geckos with vertically retractible claws. Sesamoids occur dorsal to the metatarsal­ phalangeal joints of fingers 1 to 4. PES: Phalangeal formula 3,3,4,5,4 (Fig. 2a). Two sesamoids, of which the one is minute, lie ventral to the first tarsal. Metatarsals 1 to 4 long, thin and moderately spread, while the fifth is very short and hook­ shaped. The distal condyle of the fifth metatarsal has a laterally enlarged articulation surface which allows the fifth toe to be opposed to the other toes. Apart from the terminal two phalanges which are of similar shape and size in all toes and are turned upwards, all the other phalanges are elongate and slightly curved in the vertical plane. Sesamoids occur dorsal to the metatarsal-phalangeal joint of toe 1 to 4 and the 1st inter­ phalangeal joint of toe 4. 7. Chondrodactylus angulifer (TM 31606 male, TM 31609 female) MANUS: Phalangeal formula 3,3,4,4,3 (Fig. 3b and c). No supernumerary bones in the carpus. The 5th carpal has a well developed ventral projec­ tion (cf. Fig. 3c). The metacarpals are subequal in length with wide, flattened distal ends. The 1st and 5th metacarpals have a swelling on the outer side of the distal condyle and the corresponding fingers do not 76 continue along the axis of the metacarpals but form a slight angle towards the other toes. This lateral swelling of the outer metacarpals appears to act as a support while the hand bears the weight of the body. The 1st phalanges of all fingers are subequal in length to one another and slightly curved, with flattened distal condyles. The 2nd phalanges of fingers 3 and 4 are only about one third of the length of the respective 1st phalanges. The penultimate phalanx of each finger is minute and roughly kidney­ shaped and is folded backwards over the preceding phalanx. The terminal phalanx of each finger has degenerated to a small granule which may still have a small tip indicating the original position of the claw. As the terminal two phalanges are folded back and completely embedded in tissue, the tip of the finger is thus formed by the distal condyle of the 1st phalanx of fingers 1,2 and 5 and the 2nd of fingers 3 and 4. Minute sesamoids occur dorsal to the metacarpal-phalangeal joint of fingers 2 to 4 in the female. The fingers are widely spread so that the 1st and 5th point in opposite directions. PES : Phalangeal formula 3,3,4,5,4 (Fig. 3 a, d, e, f). A single sesamoid occurs ventral to the 1st tarsal. Metatarsals 1 to 4 are elongate and only moderately spread while the 5th is very short with a wide, flattened hook which covers a fair part of the palmar surface. It has also a ventral process which ends in a heel-like structure near the skin surface of the palm (cf. Fig. 3d). The distal condyle of the 5th metatarsal has a laterally enlarged articulation surface which permits the 5th toe to be completely opposed to the other toes. The 2nd phalanx of the 3rd toe and the 3rd of the 4th toe are very short and relatively flattened. The penultimate phalanges of all the toes are also small and kidney-shaped, as described for the manus. The terminal phalanx is only a minute granule with a pointed projection. In the male this projection is short and no longer penetrates the skin (Fig. 3e i and ii), while in the female it is spine-like, curved and bears the minute claw which penetrates the skin on the dorsal side of the toes (Fig. 3f i and ii). In toe 3 and 4 of the female the terminal, claw-bearing phalanx occurs directly above the joint between the 1st and 2nd and the 2nd and 3rd phalanges of the respective toes (cf. Figs. 3d, e i and ii) while in males the tips of the toes are not as strongly recurved as is in the females (cf. Fig. 3f i and ii). A minute sesamoid was seen dorsal to the metatarsal-phalangeal joint of toe 3. Cleared specimens of the appendages of the following genera and spe­ cies were prepared for comparative purposes:

GEKKONINAE: Afroedura transvaalicaJ Aristelliger georgensis, Cnemaspis

africanusJ Ebenavia inunguis, Gymnodac(ylus scaber, Homopholis wahl­

bergii, Lygodacrylus capensisJ Narudasia festiva, Pac~dacryltls austeniJ

P. bibronii (Fig. 4a) P. kochii (Fig. 4d and e) P. mariquensisJ P. punctatus

(Fig. 4b), Phelsuma dubia, Prychozoon kuhliJ Pryodacrylus hasselquisti, Quedenfeldtia trac~blepharus, Rhoptropella ocellata, Rhoptropus afer (Fig. 4c), Stenodacrylus sthenodacrylus (Fig. 1d and e), Tropiocolotes steudneri. EUBLEPHARINAE: Cole01!Jx variegatus (Fig. 1h and i), Holodacrylus africanus (Fig. 1£ and g). SPHAERODACTYLINAE: Sphaerotiacrylus picturatus. 77

The basic elements in the carpus and tarsus are similar in all the species examined. No intermediale was noticed, while the first tarsal was present in all cases, which is supposed to be the general condition in geckos (Camp, 1923; Stephenson, 1960; Wellborn, 1933). The pisiforme, al­ though always present, varied considerably in relative size. Loose sesa­ moid bones occur in various positiorts in the carpus in a number of genera but only Ptenopus and Stenodactylus have the large palmar palate which, according to Romer (1956), is common in lizards. Considerable variation is found amongst the metatarsals; 1 to 4 are usually slender and elongate while the 5th is short and hook-shaped. Goodrich (1916 as quoted by Bellairs, 1957 and Jollie, 1961) considered this hook-shaped 5th metatarsal as characteristic for the diapsid reptiles and therefore of taxonomic im­ portance. The shape and size of this bone is very variable. Amongst the specimens examined it is best developed in Ptenopus where it is elongate and dearly recognizable as a metatarsal (Fig. la and b). However in most other species, especially those with opposable fifth toes it is extremely reduced in size. In the past certain authors have actually mistaken it for the 5th tarsal (Hoffmann, 1881 as quoted by Wellborn, 1933; Baer, 1964 pI. 16: 125.). In the species with an opposable £fth toe the distal condyle of the cor­ responding metatarsal has a particularly well developed articulation sur­ face. It is strongly convex and extends proximally onto the femoral side, thereby allowing maximum lateral mobility of the minimus. A similar situation is found in the interphalangeal joints of the hands and feet as well as the phalangeal-metacarpal and phalangeal-metatarsal joints of all the pad-bearing and secondary padless species. The distal condyles of these rather loosely articulated joints are hemispherical, permitti maximum mobility in all directions. In contrast to these the straight-t padless species have flattened articulation surfaces in the interphalangeal joints, permitting only a limited amount of lateral movement of the phalanges. Paraphalanges, i.e. cartilaginous to ossified riblike, lateral supports occur in the phalanges of certain geckos with wide terminal pads as in Ptyodactylus and are particularly well developed in Palmatogecko and to a lesser extent in Kaokogecko. The complete absence of these struct­ ures in Prychozoon) the so-called Flying Gecko, another genus with com­ pletely webbed hands and feet, is interesting and indicates different functional requirements of the appendages in this genus.

DISCUSSION The primitive phalangeal formula for pentadactyl lizards is 2, 3, 4, 5, 3 for the manus and 2, 3, 4, 5, 4 for the pes (Guibe, 1970; Jollie, 1962; Romer, 1955 and 1956; Stephenson and Stephenson, 1956; Stephenson, 1960; Wellborn, 1933). The geckos are usually considered to be the most primitive of living lizards (Stephenson, 1960). However, as they are a highly specialised and an extremely successful group it is better to refer to them as an archaic family (Underwood, 1954). Although the primitive formula is still found in many species, variations occur, often as a result of adaptations. The number of phalanges in the digits is supposed to be characteristic for a species. All the phalangeal formulae of gekkonids known to me are 78 listed below according to their composition and Kluge's (1967) grouping of subfamilies. manus pes DIPLODACTYLINAE: 2,3,4,5,3 2,3,4,5,4 Carphodacrylus laevis, Diplodacrylus i. ichaelseni, D. vittatus, Hoplodacrylus sp., Lucasi!;s damaeus, Naultinus sp., Oedura leseuri, Pf?yllurus milii, P. platurus. 2,3,4,4,3 2,3,4,5,4 Rl[ynchoedura ornata. 2,3,4,4,3 2,3,4,4,4 Nephrurus asper. 2,3,3,3,3 2,3,3,3,3 Nephrurus laevis

EUBLEPHARINAE: 2,3,4,5,3 2,3,4,5,4 Coleo!!Jx elegans, C. fasciatus, C. mitratus, C. reticulatus, C. variegatus, Holodacrylus ajricanus. 2,3,4,4,3 2,3,4,5,4 Coleo!!Jx brevis

SPHAERODACTYLINAE: 2,3,4,5,3 2,3,4,5,4 5phaerodacrylus picturatus.

GEKKONINAE: (a) Padless 2,3,4,5,3 2,3,4,5,4 Ptenopus carpi, P. garrulus, P. kochi, Quedenfeldtia tracf?yblepharus, Tropiocolotes steudneri. 2,3,4,5,4 2,3,4,5,4 Narudasia festiva. 2,3,3,4,3 2,3,3,4,3 Stenodacrylus sthenodacrylus. 2,3,3,4,3 2,3,4,4,3 Stenodacrylus sthenodacrylus (Wellborn, 1933). (b) Pad-bearing or secondary padless. 2,3,4,5,3 2,3,4,5,4 Afroedura transvaalica, Aristelliger georgeensis, A. praesignis, Cnemaspis ajricanus, Crenodacrylus ocellatus, Ebenavia inunguis, Gecko verticillatus (= Gekko gecko), G. vitlatus, Gef?yra (= Pero­ pus) variegata, Gymnodacrylus scaber, Heteronota binoei, Homopholis wahlbergii, Lepidodacrylus woodfordi, Lygodacrylus capensis, Phelsuma dubia, Pf?yllodacrylus marmoratus, Prychozoon kuhN, Pryodacrylus hasselquisti, Rhoptropella ocellala, Uroplates fimbriatus. 2,3,3,4,3 2,3,3,4,3 Hemidacrylus flaviviridis, H. frenatus, H. mabouia. 3,3,4,5,3 3,3,4,5,4 Kaokogecko vanZ'Yli, Pacf?ydacrylus austeni, P. bibronii, P. kochii, P. tJJariquensis, P. punctatus, Palmatogecko rangei, Rhoptropus afer, Tarentola delalandi. 3,3,4,4,3 3,3,4,5,4 Chondrodacrylus angulifer, Colopus wahlbergH. (From Wellborn, 1933; Mahendra, 1950; Stephenson & Stephenson, 1956; Stephenson, 1960; Kluge, 1962 and personal observations.) 79

By demonstrating different phalangeal formulae in the Australian geckos Nephrurus asper and N. laevis, Stephenson (1960) pointed out that little taxonomic value can be attached to this character, as different formulae may occur in the same genus. This is also the case in the genus Coleotryx (Kluge, 1962). In 5 tenodactylus sthenodactylus (= elegans sensu Loveridge, 1947), according to Wellborn (1933), the phalangeal formula is 2,3,3,4,3 for both the manus and the pes, while a specimen personally examined has 2,3,3,4,3 and 2,3,4,4,3 (Fig. ld and e) phalanges. It is impossible to check Wellborn's specimen now. The supernumerary phalanx observed in finger 5 of a cleared Narudasia specimen was not confirmed in a specimen studied by Dr A.P. Russell (pers. comm.) which could be another indication that individual variation could occur within a species. It is interesting to note the number of Ethiopian forms (Tarentola has a wider distribution, but is apparently of north African origin; Kluge, 1967: 49), which have diverted from the primitive formula by adding a phalanx in the 1st digit of both manus and pes. Hyperphalangy appears to be relatively rare in reptiles. Romer (1956: 407) states that the primitive formula is adhered to by many later types but occasionally a 4th phalanx may occur in the 5th. finger for example in certain skinks (cf. Narudasia). He also claims "It is exceeded only in the paddle-like limbs in aquatic forms". Brachyphalangy, on the contrary, is a relatively frequent occur­ rence and as it is common in geckos, this can be of little taxonomic im­ portance, as has been pointed out by Stephenson (op. cit.). Thus, in an evolutionary sense, it is more difficult to add a phalanx than to lose one and hyperphalangy can therefore be considered of greater importance than brachyphalangy in a phylogenetic study. For this reason it can be assumed that those pad-bearing and secondary padless geckos which show hyperphalangy of the pollex and hallux are closely related and may have had a common ancestor. Because of its known distribution the evolution­ ary centre for this characteristic appears to have been in Africa. The genera examined by the author can be divided into two groups on the basis of the structure of the appendicular skeleton. (a) Claws not retractile, toes straight and without adhesive pads. Coleotryx, Holodactylus, Quedenfeldtia, Narudasia, Ptenopus, Stenodactylus, Tropiocolotes. (b) Claws retractile, sub digital adhesive lamellae present. (Both characters may have undergone various degrees of reduction in different species). Afroedura, Aristelliger, Chondrodactylus, Cnemaspis, Colopus, Ebenavia, Homopholis, Kaokogecko, Lygodactylus, Pacqydactylus, Palmatogecko, Phelsuma, Ptychozoon, Ptyodactylus, Rhoptropella, Rhoptropus. In the members of group (a) there is no indication that the tips of their digits have ever been vertically retractile as in pad-bearing forms. As the general structure of their digits is very similar to that of other terrestrial Lacertilia with unspecialized appendages (cf. Romer, 1956), this condition is interpreted as a retention of an ancestral pattern, instead of a reversion to it. These genera are thus considered as being primarily terrestrial and padless. This is contrary to Underwood's (1954: 489) impression, that the original Gekkoninae were pad-bearing and that consequently all pad less forms are secondarily padless. The pad-bearing members of group (b), when not actually clinging to 80 an object, curl the tips of their digits up vertically. In this way the delicate adhesive lamellae and the minute claws are removed from contact with the substratum. As this retracted position is still maintained in the "clawless" and padless genera, such as Chondrodacrylus (Fig. 3a-f) and Palmatogecko (Fig. 2e and f), it is assumed that they were also pad-bearing with claws on all digits and only lost these organs fairly recently. This condition is regarded as a sign of an advanced degree of adaptation to a terrestrial way of J4fe where especially the adhesive pads have lost their importance. For this reaon these genera are referred to as being secondarily padless, while phylogenetically still belonging to the group of pad-bearing forms. It is here assumed that the earliest gekkonine ancestors were straight-toed, terrestrial lacertilians, of which some acquired subdigital adhesive lamel­ lae which enabled them to change their habits and become arboreal or rupicolous climbers. The pad-bearing and secondarily padless genera of burrowing geckos under discussion have thus reverted to the original way of life. This suggests that Underwood's group of diplodactyline geckos from southern Africa is very heterogeneous and that Ptenopus is not closely related to the other genera at all. Apart from their common gekkonid origin, the affinities between the pad-bearing and secondarily padless burrowers and Ptenopus are limited to a similarity in their way of life. Diagram 1 indicates the possible phylogenethic relationship of the Ethiopian Gekkoninae as suggested by the structure of their appendages.

Primarily terrest. Pad-bearing Pad-bearing prim. or brachyphal. climber, e.g. climber, e.g. form., e.g. Ptenopus Rhoptropus Afroedura

Str. toed climber, Sec. terrestr., Sec. terr., hyperphal. form., pad-bearing or theoretical. e.g. Narudasia padless, e.g. ColoPlis

Hyperphalangeal Primitive or formUla.y brachyphalangeal formula.

Straight toed, Pad-bearing with primitive formula, retractile claws, terres trial. primitive formula, climbers.

Straight toed, terrestrial ancestral Gekkoninae with primitive phalangeal formula.

DIAGRAM 1. Possible phylogenetic relationship of the Ethiopian Gekkoninae as suggested by the structure of their appendages. 81

In studying the closer affinities of the pad-bearing or secondarily pad1ess burrowing geckos, the presence of interdigital webs and paraphalangeal ribs to reinforce them in Pa/matogecko and Kaokogecko illustrates their relationship. The peculiarly shaped palmar scales of Kaokogecko and Chondrodacty/us have been commented on by Steyn and Haacke (1964: 13). A reinvestigation of the palms of Pa/matogecko and C%pus showed that similar shaped, but poorly developed scales do occur. Apart from a com­ mon tendency amongst these four genera to develop this peculiar shape no great importance is attached to these scales as their origin can be traced to imbricate scales which have become erect. The phalangeal formulae of Chondrodacty/us and C%pus are identical. The similarity is based on the loss of a phalanx of -the 4th finger which, however, in a phylogenetic study, is not supposed to be of importance (Stephenson, op. cit.). From the degenerate state of the terminal phalanges of Chondrodacty/us it is ob­ vious that they are functionally unimportant and therefore dispensable in a terrestrial way of life. Thus, brachyphalangy of the same finger does not necessarily indicate relationship, but more likely a similar degree of adaptation to a terrestrial life. This arrangement also applies to the ad­ hesive sub digital lamellae or pads which are absent in Chondrodacty/us and

Pa/matogeckoJ while Kaokogecko and C%pus have only two left on each digit. The enlarged, callous scales under the fingers of some of these geckos may be further indications of their relationship. These scales are large and wedge-shaped in Kaokogecko J only slightly enlarged in C%pus but large and blunt, protecting the finger "tips" in Chondrodacty/us. The available evidence, as listed below, thus suggests that the genera Pa/matogeckoJ

KaokogeckoJ C%pus and Chondrodacty/us are closely related to one another. In the following list absence and presence are indicated by an X and 0 respectively. Palmato- Kaoko- C%pus Chondro- gecko gecko dactylus Interdigital web . 0 0 X X Adhesive lamellae X 0 0 X En!. scales under fingers X 0 0 0 Brachyphal. 4th finger. . X X 0 0 Hyperphal. 1st digits .. 0 0 0 0

The secondarily terrestrial geckos are characterised by their cylindrical body shape in contrast to the flattened form of the true climbers. At the same time the attachment of the appendages changes from a lateral to a ventro-Iatera1 position. This enables the geckos to lift their bodies off the ground, which is more convenient for walking on any flat surface, and at the same time extends their range of vision. An interesting correlation was noted to exist between the structure of the 4th toe and the habits of the different species. In all truly terrestrial forms, irrespective of whether they are pad-bearing, padless or second­ arily padless, the 4th toe continues in a more or less straight line along the axis of the 4th metatarsal. This condition is present in Chondrodacty/us (Fig. 3a), Co/e01"!yx (Fig. Ih), C%pus (Fig. 2a), H%dacty/us (Fig. 1f),

Kaokogecko (Fig. 2c), Pachydacty/us austeniJ P. kochii (Fig. 4d), P. mariquensisJ 82

Ptenopus carpi, P. garrulus (Fig. 1a), P. kochi and Stenodactylus sthenodactylus (Fig. 1d). In these species the 4th metatarsal is of similar length to metatar­ sals 1 to 3. However, in true climbers, again irrespective of whether they are pad-bearing, such as Afroedura transvaalica, Homopholis wahlbergH, Pac~dactylus bibronii (Fig. 4a) and Rhoptropu.1 afer (Fig. 4c) or primarily padless as in Narudasia festiva, the 4th metatarsal is considerably shorter than the 3rd and the digit is bent outward at an angle at the metatarsal­ phalangeal joint. In the genus Pac~dactylus species with intermediate habits are found. They are ground-living but do not burrow and are still able to climb, as for example P. punctatus (Fig. 4b). In such cases the 4th toe is not as strongly bent as in true climbers, such as P. bibronii. They thus take up an intermediate position between the climbers and true ground dwellers. As the genus Pacl?ydactylus, with its large number of species (cf. Loveridge, 1947 and Wermuth, 1965), has all intermediate stages from true climbers to truly terrestrial forms an "anatomical row" (cf. Boker, 1935: 82) could be drawn up. This could show the transition from climbers with bent 4th toes and a large number of adhesive lamellae to sec;:ondary terrestrial forms with straight 4th toes and a reduced number of subdigital lamellae. This row could be continued by adding to it the highly specialized terrestrial, pad-bearing or secondarily padless genera, as indicated in diagram 2. Although there are indications that the habits of all geckos can be deduced from the angle of the metatarsal-phalangeal joint, inadequate material at this stage does not permit a more definite .;:onclusion.

Pachydactylus Pa/maiogecko Kaokogecko C%pus Chondrodacty/us arboreal to terrestrial P'y yO" webbed brachyphalangeal 4th fingers

Pad-bearing with hyperphalangeal 1st toes and fingers.

DIAGRAM 2. Possible phylogenetic relationship of the pad-bearing burrowing geckos of southern Africa.

As there is considerable similarity between the general anatomy of Pac~dactylus and that of the four pad-bearing or secondarily padless genera of burrowing geckos, the differences in the appendages can be viewed as a continuation of the evolutionary trend towards a more spe­ cialized terrestrial life, similar to that discussed above for Pac~dactylus. Indeed, the four burrowing genera appear to be more closely related to Pachydactylus than was hitherto suspected, while Ptenopus, which belongs to a different evolutionary line, is much further removed than was sug­ gested by Underwood (1954). 83

CoNCLUSIONS (a) Pupil shape is unsuitable for separating subfamilies, as the Diplo­ dactylinae (sensu Underwood, 1954) of southern Africa have a variety of shapes according to which they belong to more than one subfamily. Kluge's (1967) treatment of the geckos is accepted while Underwood's (1954) classification must be rejected for this reason. (b) The primitive phalangeal formula for pentadactyl lizards is 2,3,4,5,3 for the manus and 2,3,4,5,4 for the pes. This formula applies to the geckos. Brachyphalangy or the loss of phalanges in gekkonid append­ ages is common and of little phylogenetic importance. (c) Hyperphalangy or t1-te presence of additional phalanges in the append­ ages of geckos is relatively rare and of greater phylogenetic import­ ance. The Mrican geckos Chondrodacrylus, Colopus, Kaokogecko, Pac~dacrylus, Palmatogecko, Rhoptropus and Tarentola have an extra phalanx in the 1st finger and toe. This is considered to be of phylo­ genetic importance, indicating that these genera form a related group. (d) The peculiar feet of the terrestrial geckos Chondrodac!ylus, Colopus, Kaokogecko and Palmatogecko are considered to be adaptations to a specialised way of life and thus of minor taxonomic importance. (e) Ptenopus has a primitive phalangeal formula and is primarily padless, which makes it unique in southern Africa. This genus is therefore not as closely related to the other burrowing genera as was suggested by Underwood (1954). (f) The angle of the metatarsal-phalangeal joint of the 4th toe is an indica­ tion of the habits of a gecko. Terrestrial forms have straight 4th toes while arboreal or rupicolous forms have a relatively short 4th meta­ tarsal and the toe is bent backwards at the joint. Intermediate stages occur according to the habits of a species.

SUMMARY 1. Interpopulation variation in Ptenopus garrulus is studied. Statistical evidence is produced proving that the subspecies maculatus is distinct and is restored. The distribution of P. garrulus coincides closely with the 500 mm rainfall isoyhet and the typical form and the subspecies maculatus meet along the western margin of the Karahari sand. 2. Ptenopus carpi and P. kochi occur in the below 125mm mean average annual rainfall zone within which their respective distribution is determined by the particular substratum to which they are adapted. 3. The distribution of Palmatogecko is determined by the presence of loose sand within the 125mm mean annual rainfall zone. Interpopu­ lation variation is not of subspecHic level. 4. The known distribution of Kaokogecko is very limited and in certain areas this gecko appears to occur sympatrically with Palmatogecko. However, differences in habitat preference apparently reduces direct competition. 5. The distribution of Colopus wahlbergii, a Kalahari endemic, does not show a clear correllation with rainfall as shown by the other burrow­ ing geckos. A subspecies, C.w.jurcifer, associated with the dune area of the south-western Kalahari is described. 84

6. The distribution of Chondrodacrylus angulijer coincides closely with that area feceiving less than an average of about 300mm of rain per year. A desert form, Ca. namibensis, is described here. 7. The burrowing geckos of southern Africa are terrestrial, nocturnal or diurno-nocturnal species and consequently have large eyes (cf. Werner, 1969). The perera ratios are as follows:

N Range x PJenopus g. garru/us . 10 (Kangyane) 5,7 - 6,6 6,0 P.g. maculaJus . . 11 (c. Namib) 5,6 - 6,5 6,2 P. carpi 27 7,2 - 8,4 7,9 P. kochi .. 28 5,8 6,9 6,4 PalmaJogecko rangei . 41 6,4 - 7,9 7,1 Kaokogecko vanz.yli . 32 6,1 7,8 6,9 C%pus w. wahlbergii 41 5,5 - 7,0 6,1 C.w. furdfer. . 39 5,9 - 7,2 6,5 ChondrodacJyius a. angulifer . 19 6,6 - 8,9 7,4 C.a. namibensis. . 19 6,8 - 9,1 7,6 8. Tail autotomy varies considerably in frequency and position amongst the various forms. Orig. Regen. tail Lost tail Species N tail At Post. At Post. base to base base to base Plenopus garru/us 292 64,7% 2,4% 17,5% 3,4% 12,3% P. kochi 61 57,4% 3,5% 29,6% 8,0% 1,6% P. carpi 46 73,9% 0,0% 17,4% 2,2% 6,5% PalmaJoguko rangei 294 79,6% 10,5% 0,0% 9,9% 0,0% Kaokogecko tlanUIi 61 82,0% 13,1% 1,6% 3,3% 0,0% C%pus w. wah/bergii 142 58,6% 27,5% 1,2% 12,7% 0,0% C.w. furcifer 50 44,0% 20,0% 12,0% 22,0% 2,0% ChondrodacJy/us a. angulifer 84 72,6% 9,5% 13,1% 1,2% 3,6% C.a. namibensis 38 71,1% 10,5% 15,8% 2,6% 0,0% This indicates that autotomy is restricted to the base in Palmatogecko, Kaokogecko and typical Colopus wahlbergH, although a single individual in both the latter forms was observed with a partially regenerated tail. In all the other forms autotomy can take place at any point. It is interesting to note that typical Colopus wahlbergii appears to have a restricted autotomy area while the new subspecies furcijer autotomizes at any point. 9. The pupil shape, as used by Underwood (1954), is unsuitable to dis­ tinguish subfamilies of southern African geckos. 10. Ptenopus has a primitive phalangeal formula and is considered to be primarily straight-toed and padless. 11. Hyperphalangy occurs in the first digits of Palmatogecko, Kaokogecko, Colopus and Chondrodacrylus, a character which they share with other pad-bearing African geckos. This is considered to be an indication of relationship. These four genera are thus more closely related to other climbing pad-bearing geckos than to Ptenopus. The only affinity Ptenopus has with the other burrowing geckos is a similarity in their way of life. 12. The structure of the 4th toe of geckos is an indicator of the degree of adaptation to a terrestrial life. 85

REFERENCES (For further references see Part 1) BAER, J .c., 1964. Comparative Anatomy of Vertebrates. London, Butterworths. BELLAIRS, A. d'A., 1957. Reptiles. London, Hutchinson's University Library. BOKER, H., 1935. Einfuhrung in die Vergleichende Biologische Anatomie der Wirbel- tiere. Jena, Gustav Fischer .. BOULENGER, H.A., 1885. Catalogue of the Lizards in the British Museum (Natural History). 2nd Edit. 1: 1-436. London, Trustees of the British Museum (Nat. Hist.). CAMP, c.L., 1923. Classification of the Lizards. Bull. Am. Mus. nat. Hist. 48: 289-481. COGGER, H.G., 1964. The Comparative Osteology and Systematic Status of the Gek­ konid Genera Afroedura Loveridge and Oedura Gray. Proc. Linn. Sod. N.S. W. 89: 364-72. DIXON, J.R. and KLUGE, A.G., 1964. A New Gekkonid Lizard Genus from Australia. ,Copeia 1964: 174-80,4 figs. GOODRICH, EDWIN S., 1916. On the Classification of the Reptilia. Proc. R. Soc. (B) 89: 261-75, 4 figs. GUIB~, J., 1970. Le Squelette du Tronc et de Membres. In: Traite de Zoologie 14(2): 33-77. Paris, Masson et Cie. HAACKE, W.D., 1975. The Burrowing Geckos of Southern Africa, 1. Ann. Transv. Mus. 29: 197-247,4 figs, 2 plates. HEIDSIECK, E., 1928. Der Bau der Skeletteile der freien Extremitaten bei den Reptilien. Gegenbaurs morpb.Jb. 59: 343-492. JOLLIE, M.,l961. Chordate Morphology. New York, Reinhold Publishing Corpora­ tion. KLUGE, A.G., 1962. Comparative Osteology of Eublepharid Lizard Genus Coleonyx Gray.]. Morpb.110:299-332, 17 figs. --, 1964. A Revision of the South American Gekkonid Lizard Genus Homonota Gray. Am. Mus. Novit. 2193: 1-41, 12 figs. --,1967. Higher Taxonomic Categories of Gekkonid Lizards and their Evolution. Bull. Am. Mus. nat. Hist. 135: 3-60, 8 figs. LOVERIDGE, A., 1947. Revision of the African Lizards of the Family Gekkonidae. Bull. Mus. compo Zool. 98: 1-469, 7 pis. MAHENDRA, B.C., 1950. The Osteology of the Indian House-gecko, Hemidactylus flaviviridis Ruppel. Proc. Zool. Soc. Beng. 3: 49-63, 5 figs. PASTEUR, G., 1960. A propos de la pupille des Diplodactylines du genre Saurodactylus Fitzinger. C.r. Sianc. mens. Soc. Sci. nat.pbys. Maroc. 7: 128. . ROMER, A.S., 1955. The Vertebrate Body. 2nd Edition. Philadelphia, W.B. Saunders Company. --, 1956. Osteology of the Reptiles. Chicago, The University of Chicago Press. STEPHENSON, N.G., 1960. The Comparative Osteology of Australian Geckos and its Bearing on their Morphological Status.]. Linn. Soc. 44: 278-99, 8 figs. --, and STEPHENSON, ELSIE M., 1956. The Osteology of the New Zealand Geckos and its Bearing on their Morphological Status. Trans. R. Soc. N.Z. 84: 341-58, 6 figs. STEYN, W. and HAACKE, W.D., 1966. A new Webfootee. Gekko (Kaokogecko vanzyli gen. et. sp. nov.) from the North-Western South West Africa. Cimbebasia 18: 1-23,9 figs, 7 pis. UNDERWOOD, G., 1954. On the Classification and Evolution of Geckos. Proc. Zool. Soc. Lond. 124: 469-92. --,1955. Classification of Geckos. Nature, Lond. 175: 1089. WELLBORN, W., 1933. Vergleichende osteologische Untersuchungen an Geckoniden, Eublephariden und Uroplatiden. Sber. Ges. naturj. Freunde Berl. 1933: 126-99, figs. WERMUTH, H.W., 1965. Liste der rezenten Amphibien und Reptilien. Gekkonidae, Pygopodidae, Xantusiidae. Tierreicb 80: I-XXII, 1-246. 86

FIG. 1. Dorsal or lateral views of skeleton of right appendages of: (a) Pes of PtenoplU garrulur; (b) Pes of P. ga"ullU; (e) Manus of P. ga"uilU; (d) Pes of Stenoda&tyllU rlhenoda&tyllU; (e) Manus of S. rlhenoda&tyllU; (f) Pes of Holoda&tyllU aJri&anlU; (g) Manus of H. aJricanlU; (h) Pes of Coleonyx IJariega/lU; (i) Manus of C. IJariegalur. (F femur; mt = metatarsalia; R = radius; s = sesamoid bones; T = tibia; tf = tibio-fibulare; U ulna). 87

FIG. 2. Dorsal view of the skeletons of the right appendages of: (a) Pes of Colopu. wahlbergii; (b) Manus of C. wahlbergii; (c) Pes of Kaokogecko van~'yli; (d) Manus of K. vanzyli; (e) Pes of Palmatogecko rangei; Cf) Manus of P. rangei. (pp = paraphalanges). 88

e I)

f I) II)

4. 5

FIG. 3. Skeleton of tight appendages of Chondrodactylm angulifer: (a) Dorsal view of pes of female. (b) Dorsal view of manus of female ; (c) Lateral view of manus of female showing fingers 4 and 5. (d) Lateral view of pes of female showing toes 4 and 5; (e) (i) Lateral view of tip of 4th toe of male; (ii) Lateral view of tip of 5th toe of male; (f) (i) Lateral view of tip of 4th toe of female; (ii) Lateral view of tip of 5th toe of female. (c = carpalia; ce centrale; cu = cuboid; me = metacarpalia; p = phalanges; pi = pisiforme; u = ulnare). 89

a

5

~/ / / I / /'

,///

I I I ,I

I I

FIG. 4. Dorsal view of skeleton of right appendages of: (a) Pes of Pachydactylus bibronii; (b) Pes of Pachydactylus punctatus; (c) Pes of Rhoptropus afer; (d) Pes of Pachy­ dactylus kochii; (e) Manus of P.kochii.