Currently, the family Gerrhosauridae Fitzinger, 1843 comprises 35 recognized species with seven of them assigned to the genus Gerrhosaurus Wiegmann, 1828 distributed in sub-Saharan Africa (The Reptile Database; Uetz, Goll and Hallermann, 2007; available through http://reptile-database.reptarium.cz/advanced_search?taxon=Gerrhosauridae&submit=Search; last access 25.11.2011). Gerrhosaurus flavigularis Wiegmann, 1882 (Fig. 1A) is distributed from the Republic of South Africa and Namibia through eastern Africa to Ethiopia and eastern parts of Sudan. It is a large (SVL <45 cm) oviparous lizard inhabiting stony savannahs and bushland (Spawls et al., 2002). Information on reproductive aspects of wild individuals is rare. Spawls et al. (2002) mentioned that hatchlings were observed in Kerio Valley, Kenya, in July.

During the last decades, the species was frequently imported to Europe for pet trade. Nevertheless, there are only very few, often anecdotal reports on its reproduction in both the wild and in captivity (i.e. FitzSimons, 1943; De Waal, 1978; Boycott and Morgan 1988; Kober 1990; Branch et al., 1992).

In 2006, we obtained a pair of G. flavigularis exported according to the importer from the Democratic Republic of Congo (outside the known distribution) via pet trade, which was kept in a standard terrarium (length 110 cm x breadth 60 cm x height 45 cm). Temperatures were kept between 23 and 27 °C without major seasonal variations, but the two specimens were separated for several months due to an injury of the female. Shortly after again co-housing them in January 2011 mating activities were observed. Subsequently, the female deposited three clutches of each five eggs on February 10th, March 15th and May 10th (Fig. 1B, C) suggesting a minimum gestation period of 25 days. Clutch sizes corroborate well with previous observations (i.e. 3-8 eggs; cf. FitzSimons, 1943; De Waal, 1978; Boycott and

Morgan, 1988; Kober, 1990; Branch et al., 1992). Using Vermiculite as substrate, the first clutch was

incubated in a standard incubator (Bruja 3000) at 26-27°C and the second and third at 27°C. During the incubation time, we recognized a strong moisture dependence of the eggs, which almost doubled their size during incubation (Fig. 1D, E) (not measured). Such strong size differences were also reported by Branch et al. (1992), who compared measurements of eight day old eggs with data presented by FitzSimons (1943), De Waal (1978) and Boycott and Morgan (1988).

From the first clutch, the juveniles hatched after 82 to 86 days and from the second clutch after 81 to 82 days (Fig. 1F), but, unfortunately, all eggs of the third clutch did not develop. Compared to incubation and hatchling data provided by Kober (1990), who incubated three eggs of G. flavigularis at 28 °C (daytime) and 22 °C (nighttime), our incubation time was much shorter (81-86 vs. 122-153 days). On average, hatchlings had a snout-vent length (SVL) of 49.0 mm and a tail length (TL) of 105.1 mm, which is longer than reported by Branch et al. (1992: SVL = 37.7 mm, TL = 61.3 mm, n = 1) but similar to the average total length of 150

Herpetology Notes, volume 5: 13-14 (2012) (published online on 14 January 2012)

Notes on the reproduction of the Yellow-Throated Plated Lizard Gerrhosaurus flavigularis Wiegmann, 1882

Sascha Esser and Dennis Rödder*

Zoologisches Forschungsmuseums A. Koenig, Adenauerallee 160, D-53113 Bonn, Germany;

*Corresponding author; e-mail: d.roedder.zfmk@uni-bonn.de

SpecimenNo. HW HL SVL TLClutch1

1 9.4 14.0 53.4 126.72 9.3 13.2 50.3 113.9 3 9.7 14.0 55.0 125.84 9.2 13.4 51.8 120.75 9.3 13.5 55.7 127.8

Clutch 2 1 7.4 13.5 48.7 101.32 7.5 13.7 48.1 108.23 7.6 13.0 48.9 101.74 8.6 1325 49.0 104.35 8.2 13.2 50.5 112.1

Table 1. Measurements (in mm) of juvenile Gerrhosaurus flavigularis from the first clutch ca. one month after hatching as well as measurements of juveniles from second clutch shortly after hatching. Abbreviations are: HW= head width; HL = head length; SVL = snout-vent length; TL = tail length.

Sascha Esser & Dennis Rödder14

mm reported by Kober (1990). Other measurements are presented in Table 1. All juveniles readily feed on small insects like crickets and house flies as well as on yoghurt and smashed fruit.

ReferencesBoycott, R.C., Morgan, D.R. (1988): Reproductive and growth

data of some South African lizards. J. Herp. Assoc. Afr. 35: 15-18.

Branch, W.R., Van Wyk, J.C.P., Kok, D.J., du Preez, L.H., Haagner, G.V., McCartney, J.C., Branch, T.C. et al. (1992): Life History Notes. J. Herp. Assoc. Afr. 41: 40-45.

FitzSimons, V.F. (1943): The lizards of South Africa. Mem. Transvaal Mus. 1 (528pp).

Kober, I. (1990): Im Terrarium gezüchtet: Gerrhosaurus flavigu-laris. Aquar.- Terrar.-Z. 43: 24-45.

Spawls, S., Howell, K.M., Drewes, R.C., Ashe, J. (2002): A Field Guide to the Reptiles of East Africa. San Diego (Academic Press), 543 pp.

Uetz, P., Goll, J., Hallermann, J. (2007): Die TIGR-Reptilienda-tenbank. Elaphe 15: 22-25.

De Waal, S. (1978): The Squamata (Reptilia) of the Orange Free State South Africa. Mem. Nas. Mus. Bloemfontein 11: 1-160.

Figure 1. Aspects of the reproduction of Gherrosaurus flavigularis. (A) basking female; (B) specimen depositing eggs; (C) the second clutch; (D) one day old egg; (E) comparison between the sizes of an one day old egg (right) with an egg shortly before hatching (left); (F) group of one month old juveniles of the first clutch.

Accepted by Wouter Beukema; Managing Editor: Philipp Wagner