Description of a new species of Cordylus Laurenti (Reptilia: Cordylidae) from the south-western Cape, South Africa

A new species of girdled lizard in the Cordylus genus is described from the south-western Cape, South Africa. Unlike other Cordylus taxa the new form usually has only two supraciliaries per side, the posterior parietals are usually separated mesially by a small post-interparietal scale and the lateral body scales are larger than the dorsal scales. The relationships of this new form to other members of the Cordylus group are discussed

Paradoxical reproduction and body size in the rock lizard, Agama atra atra, in Namaqualand, South Africa

The original publication is available at http://africanzoology.journals.ac.za/pub.The rock lizard Agama atra atra from Namaqualand differs in both body size and reproduction from other populations of this species occurring elsewhere in southern Africa. Both sexes from Namaqualand are significantly larger than their counterparts in the south-western Cape. While reproduction in this species is strongly seasonal elsewhere, it is apparently continuous in Namaqualand. Females with vitellogenic ovarian follicles and/or oviducal eggs were collected during the winter months, a time when females are typically reproductively quiescent in other populatlons. Aseasonal reproduction and large body size of this species in Namaqualand do not correlate with prevailing environmental conditions in the area.T he presence of at least one other species with continuous reproduction and two others with tropical affinities in the same general area, suggests that the Namaqualand population of A. a. atra may be a tropical relict.Publisher's versio

A model explaining patterns of geographic character variation in Cordylus cordylus (Reptilia; Cordylidae) in the south-western Cape, South Africa

A model is proposed for the evolution of three morphotypes of the girdled lizard Cordylus cordylus (Linnaeus) in the south-western Cape. The available data are interpreted as indicating that a vicariant splitting of a warm-adapted ancestral population during the last glacial period occurred. Differential evolution of the two daughter populations in response to different environmental pressures resulted. One of the daughter populations remaining in the coastal lowlands to the west of the Cape Fold Mountains, became cold-adapted, an event which was followed by a rapid range expansion. The other daughter population to the south and east of the Cape Fold Mountains apparently experienced less severe climatic conditions, maintained a larger population size, and for these reasons remained warm-adapted. During the subsequent warmer, interglacial period the now cold-adapted daughter population was again fragmented into two populations. Of these, one is presently found along the south-western coast and the other along the higher peaks of the western section of the Cape Fold Mountains. On the other hand the amelioration of the climate during the interglacial allowed the warm-adapted daughter population to the south and east to expand its range, eventually penetrating into the areas formerly occupied by the cold-adapted populations. Subsequently zones of secondary contact were established. In the area under discussion similar patterns of contraction and expansion can be observed in other closely related species. Our data support the turnover-pulse hypothesis of Vrba (1985)

Paradoxical reproduction and body size in the rock lizard, Agama atra atra, in Namaqualand, South Africa

The rock lizard Agama atra atra from Namaqualand differs in both body size and reproduction from other populations of this species occurring elsewhere in southern Africa. Both sexes from Namaqualand are significantly larger than their counterparts in the south-western Cape. While reproduction in this species is strongly seasonal elsewhere, it is apparently continuous in Namaqualand. Females with vitellogenic ovarian follicles and/or oviducal eggs were collected during the winter months, a time when females are typically re productively quiescent in other populations. Aseasonal reproduction and large body size of this species in Namaqualand do not correlate with prevailing environmental conditions in the area. The presence of al least one other species with continuous reproduction and two others with tropical affinities in the same general area, suggests that the Namaqualand population of A. a. atra may be a tropical relict

Cordylus Minor: A valid species of South african lizard (Reptilia: Cordylidae)

The taxonomic status of Cordylus cordylus minor FitzSimons 1943 is reconsidered. An analysis of variation in external morphological characters shows  minor and cordylus to be two non-overlapping sets of organisms. A phylogenetic study shows the minor-cordylus set to be non-monophyletic, leaving no option than to consider minor a separate species

Reproduction and sexual dimorphism in the montane viviparous lizard, Pseudocordylus capensis (Sauria: Cordylidae)

Pseudocordylus capensis, a melanistic lizard, is regarded as a basal species in the phylogeny of the family Cordylidae and is endemic to the Cape Fold Mountains. Data for this study were obtained from measurements and dissections of museum specimens (N = 68). Sexual maturity in both sexes is attained at around 80-90 mm snout-vent length (SVL). Body sizes (SVL) differed significantly between sexes, the mean SVL of adult males being 92.3 mm (range 78.4−104.2) and that of adult females 95.9 mm (range 83.1-108.5). Although the rate of increase in head measurements did not differ significantly between sexes, analysis of covariance (ancova) indicated that head dimensions are marginally, but significantly, larger in males than in females of equivalent SVL. The slight female-plus dimorphism in SVL and male-plus dimorphism in head dimensions is suggested to be related to life in the cold montane environment, and to differential growth to increase female reproductive fitness, rather than to be the result of sexual selection. Males exhibit testicular recrudescence during autumn, with full spermiogenesis during winter maintained through spring (October). The testicular cycle shows characteristics of both ‘post-nuptial’ and ‘pre-nuptial’ cycles previously described in Cordylidae lizards. Small testicular volume, associated with testicular regression, was recorded during summer (November/December). Spermatozoa were present in the epididymis from May through to October. In synchrony with the spermatogenic cycle, the onset of vitellogenesis in females starts in autumn, culminating in ovulation during spring (September-October). Females are gravid during summer and give birth to 2-3 young in late summer (December-January). The timing of events during the reproductive cycle of females corresponds to the autumn cycles reported for all other female Cordylidae lizards studied to date, therefore pointing to strong conservatism regarding the timing of female reproductive cycles in this lizard family. Fatbody size in individuals of both sexes is largest during late summer and autumn, and progressively declines during winter to reach smallest sizes during the summer months. The fact that this phylogenetically basal species exhibits well-synchronised male and female autumn gonadal cycles adds to the data that suggest these reproductive traits evolved during the early divergence from the Cordyliformes ancestor and that the evolution of viviparity may be linked to this event or followed soon after

Taxonomic status of the melanistic forms of the Cordylus cordylus complex (Reptilia: Cordylidae) in the south-western Cape, South Africa

The taxonomic status of the two melanistic morphotypes belonging to the Cordylus cordylus complex in the south-western Cape, South Africa, is considered. It is proposed that the coastal melanistic form, previously described as subspecies of C. cordylus,be considered a separate species, while the previously unknown montane melanistic form is also described as a new species. Areas of uncertainty, which may affect the status of the two melanistic species in the future, are discussed

Foraging strategies of coexisting lacertid lizards in the arid Tankwa Karoo Basin of South Africa

The original publication is available at http://africanzoology.journals.ac.za/pubFour lacertid lizards, Pedioplanis laticeps, P. lineo-ocellata, Meroles knoxii and Nucras tessellata, occur sympatrically on the arid plains of the Tankwa Karoo Basin in South Africa. The aim of this study was to evaluate the significance of foraging strategy in resource partitioning among the four species, allowing them to co-occur in a structurally simple system with a limited number of potential niches. Previous workers already identified P. lineo-ocellata and M. knoxii as sit-and-wait foragers and N. tessellata as an active forager. We recorded data on three foraging variables: movements per minute, proportion of time spent moving, and proportion of attacks on prey whilst moving, for juveniles and adults of P. laticeps. By comparing the foraging data obtained for P. laticeps to those for other lacertid species, we were able to demonstrate that adult P. laticeps are ambush foragers.We also noted a significant ontogenetic shift in foraging behaviour in P. laticeps, and, due to a significantly higher frequency of short brief movements, we classified juveniles as mixed foragers. The sharing of an ambush foraging strategy by at least three of the four lacertid species co-occurring on the Tankwa plains, suggests considerable overlap along the trophic dimension of ecological space. This overlap presumably promotes occupation of separate microhabitats by the three ambush foragers in the Tankwa Karoo Basin.Publisher's versio

Sexual dimorphism in two girdled lizard species, Cordylus niger and Cordylus cordylus

The extent of sexual selection in two girdled lizard species was evaluated by measuring sexual dimorphism in those characters normally affected by sexual selection. Neither Cordylus niger, a cool-adapted species, nor C. cordylus, a warm-adapted species, displayed any notable sexual differences in asymptotic body sizes, but both species displayed slight dimorphism in head size measurements. The C. niger sample contained more large males than large females, which may be attributed to a lower growth rate in females. In the cool Saldanha area, females of both species lack generation glands. In the warmer Gansbaai area, these glands are present in females of C. cordylus, but in lower numbers than in males. Sex ratios favouring females, have been recorded for both species. The observed sexual dimorphism in the two species seems to be mainly the result of differential energy allocation by females, and not of sexual selection perse

Morphological variation in the girdled lizard Cordylus mclachlani Mouton 1986

The girdled lizard Cordylus mclachlani, previously known only from the type locality in the south-western Cape, South Africa, was found at several new localities as far north as Nieuwoudtville. The external morphology of the 32 additional specimens thus obtained was investigated to establish the nature of geographical variation. Specimens from the type locality, which lies on the southern periphery of the known distribution range, differ from the rest in the number of suboculars, the shape of the interparietal scale and in the presence of a post-interparietal scale. Because of some overlap in these characters, separate taxonomie status for the specimens outside the type locality is not considered. The diagnostic character set for the species is updated and additional ecological information is supplied