Archaius, Vol. 1, No. 3: 18-23, 2020 Nečas, P. & al. – Quadruplets, triplets and twins 18 Quadruplets, Triplets and Twins in Chameleons (Sauria: Chamaeleonidae) PETR NEČAS 1 , SERGII PROKOPIEV, CRAIG DURBIN, JÜRGEN VAN OVERBEKE & CHRISTOPH ROTH 1 Corresponding author: petr.necas@me.com ABSTRACT A historical overview of documented occurrence of chameleon twins, triplets and quadruplets and their life history is presented, with reports on the first documented twins in Calumma parsonii parsonii (CUVIER, 1852) and Trioceros laterispi- nis (LOVERIDGE, 1932); second documented triplets in Chamaeleo calyptratus DUMÉRIL & DUMÉRIL, 1851 and Furcifer parda- lis (CUVIER, 1829) and first documented quadruplets in Chamaeleo calyptratus. Key words: Calumma parsonii, Chamaeleo calyptratus, Furcifer pardalis, Trioceros jacksonii, Trioceros laterispinis, Trioceros quadricornis, twins, triplets, quadruplets, captivity INTRODUCTION For about three decades chameleons have been gaining in popularity as pets and two species have been established in large numbers in captive populations including Chamaeleo calyptratus and Furcifer pardalis. Recently Furcifer lateralis, Furcifer oustaleti, Trioceros jacksonii and Calumma parsonii have also been successfully bred in captivity in increasing numbers. As data on the reproductive biology of chameleons in the wild are still rather scarce and there is no single observed case of twins or triplets from the wild, we rely in the study of this phenomenon, on observations from captivity, which are, unfortunately, not often published. From the hundreds of thousands of chameleons produced in captivity annually in recent years (PETR NECAS’S estimate based on analysis of internet data), the occurrence of twins or triplets is very rare, with documented observations being reported only several times in history. The occurrence of twins and triplets is likely appearing more frequently than reported, as the birth process is very rarely observed in captivity in viviparous species as well as the little more frequently but still rarely observed hatching process of oviparous species. Also, very rarely, numbers of empty eggshells are compared with the numbers of hatchlings, which often count dozens of individuals remaining the probability of noticing the twins much lower than in the case of some other reptiles, producing significantly lower numbers of eggs. It is currently unknown to what an extent conditions captivity influence the frequency of occurrence of twins and triplets. There is also virtually no base from which to assess the reasons of their appearance both in the wild and in captivity. Therefore, it can be assumed their occurrence is based solely on coincidence. There is, however, evidence collected by SERGII PROKOPIEV, that inbreeding increases the frequency of the appearance of twins significantly. HISTORICAL OVERVIEW There are known cases of only 6 species in total (including this report), of both viviparous species (2 – marked with VP) as well as oviparous species (4 – marked with OP) having been reported to produce twins: Calumma parsonii (OP), Chamaeleo calyptratus (OP), Furcifer pardalis (OP), Trioceros laterispinis (VP), Trioceros jacksonii (VP), Trioceros quadricornis (OP). There are known cases of only 2 species in total (inclu- ding this report), of oviparous species having produced Submitted: 21. 06. 2020 Published: 12. 10. 2020