Hydrosaurus celebensis

Biology: H. celebensis was observed in a variety of habitats. In particular, the habitat of H. celebensis in the Pattunuang canyon differs from that in Bantimurung and near Palopo. The Pattunuang river is very stony and during the rainy season flows at a rapid pace. Its riverbank vegetation mainly consists of trees and only a few bushes. In Bantimurung specimens of H. celebensis were spotted in certain places where H. microlophus (see above) was not found. H. celebensis inhabited more inaccessible areas with dense vegetation on the banks and was often seen on branches above the water. Near Palopo H. celebensis inhabited an area near a slow flowing river without stones or rocks. Most of the individuals were found sitting in dense, low vegetation. Some of the subadults were spotted on thin branches above the water. In some places they were also spotted high up in trees where adults could be seen resting on branches. An adult female carrying eggs could also be observed in Pattanuang towards the end of March.

Sumber: Dragons in neglect: Taxonomic revision of the Sulawesi sailfin lizards of the genus Hydrosaurus Kaup, 1828 (Squamata, Agamidae)

Description of holotype: See above.

Sumber: Dragons in neglect: Taxonomic revision of the Sulawesi sailfin lizards of the genus Hydrosaurus Kaup, 1828 (Squamata, Agamidae)

Distribution: H. celebensis is endemic to Sulawesi. It appears to inhabit the northern part of South Sulawesi, Central Sulawesi and South East Sulawesi (Figure 8). The populations in Pattunuang and Bantimurung (South Sulawesi) are possibly a result of recent introductions according to a local source (A. Siady Hamzah, Universitas Hasanuddin, Makassar, UNHAS, pers. comm.) and information on the website of the Bantimurung-Bulusaraung National Park by Taufik Ismail (2013). See also the Discussion below. Comparison between live specimens of H. microlophus and H. celebensis. Based on available photographs of live specimens from Sulawesi both species can be further distinguished by pholidosis, colouration and pattern. While some of the pictured specimens (mostly males) can be directly assigned to H. celebensis (Peters, 1872) because they have a near identical appearance to that of the type specimen, others were quite difficult to identify and could only be assigned through inference to H. microlophus. In particular, juveniles within the presumed H. microlophus populations possess the same arrangements of groups of enlarged dorsal scales as the type specimen. All adults within the same populations also show these characteristic groups of enlarged lateral scales and we therefore consider these specimens as belonging to H. microlophus. Specimens in various developmental stages of H. microlophus, were observed near Bantimurung, Bengo-Bengo / Camba and Rompegading on the southwestern peninsula of Sulawesi (Figure 8). Figure 7 depicts a juvenile specimen from Rompegading displaying the characters described by Bleeker (1860). In particular the arrangement, size and shape of the enlarged dorsal scales fit well with the type specimen. Since the adult specimens of the southwestern peninsula differ vastly from both the holotype and live specimens of H. celebensis, hence we conclude that they represent H. microlophus. Adult males (and most females) from these populations have a much more pronounced scalation on the dorsum. The enlarged scales on the dorsum of the adults are strongly keeled and have a tetrahedral appearance (vs. near flat and only slightly keeled in H. celebensis). In males these scales are black in colour and whitish to yellow in females. An additional feature seen in adult H. microlophus are the strongly enlarged scales on the anterior part of the forelimbs. This character very much resembles the description by Barbour (1911) for H. weberi who compared it to a piece of “ armour ”. The ground colour of adult H. microlophus males is generally dirty yellow, with the upper parts of the head, extremities and enlarged dorsal scales blackish. The gular region is yellowish. Adult females show a very different colouration (Figure 3 F); the general dorsal ground colour is grey to dark grey or nearly black, while the enlarged scales are light. We did not observe or find a preserved adult male specimen with such a colouration nor did we find a female specimen with dark enlarged scales as described above. The colouration of some subadult females is very similar to that observed in juvenile specimens of both sexes (i. e., grey with cream coloured enlarged scales). The change in colour and development of the shape of the scales from one that is less to one that is more pronounced appears to be in line with ontogenetic development since only adult specimens show sexual dichromatism. A second distinct phenotype (Figures 3 C & D) was photographed in the south of South Sulawesi (in the valley of the Pattunuang river and in Bantimurung) in the vicinity of a H. microlophus population and in the north of the Southwestern peninsula near Palopo (Figure 8). Males of these populations agree completely with the holotype of H. celebensis (see Figure 4 B). They only have a few enlarged scales interspersed on the dorsum and their dorsal colouration is a pattern which is black and yellow spotted with white enlarged scales dorsolaterally. This particular colouration was observed during the dry season. During the wet season several males, but not all, displayed an even richer colouration, showing contrasts with the yellow coloured scales switching to a bright orange yellow colour. Head, gular region and extremities were completely black. Typically, females were slightly duller in colouration and less rich in contrast. Unfortunately, we were not able to find a juvenile within these populations that we could refer unambiguously to H. celebensis. In both Pattunuang and Palopo where populations of H. celebensis were found, almost all juveniles had more or less slightly marked crossbands of enlarged scales. In particular, we found that the juveniles of Pattunuang agreed with the general characteristics described for the type of H. microlophus. Both in Pattunuang and Palopo adult microlophus have not been observed but in Pattunuang it is probable that they are in contact with celebensis because the next localities of microlophus are only ca. 7 km (Bantimurung) resp. about 10 km (Bengo-Bengo) away.