Bronchocela celebensis Gray, 1845

Amarasinghe, A. A. Thasun, Campbell, Patrick D., Riyanto, Awal, Hallermann, Jakob, Hamidy, Amir, Andayani, Noviar, Abinawanto, A. & Supriatna, Jatna, 2024, Taxonomy, distribution, and conservation status of a rare arboreal lizard, Bronchocela celebensis Gray, 1845 (Reptilia: Agamidae) endemic to Sulawesi, Indonesia, Zootaxa 5424 (2), pp. 189-202 : 193-199

Bronchocela celebensis Gray, 1845

( Fig. 4 ; Tables 2, 3)

Bronchocela celebensis Gray, 1845

Calotes celebensis — Boulenger 1885, Müller 1895, De Rooij 1915, Wermuth 1967

Bronchocela celebensis — Moody 1980, Malkmus 2000, Barts & Wilms 2003, Hallermann 2005, Manthey 2008, Wanger et al. 2011, Koch 2012

Holotype. NHMUK 1946.8.11.48, collected from Celebes (Sulawesi), Indonesia, and entered to the museum registry on 22 February 1844 (received from Leyden Museum).

Diagnosis. A species of Bronchocela inhabiting Sulawesi Island, Indonesia, characterized as follows: morphologically most similar to its congener B. cristatella in body colouration, but differs by having non-enlarged (vs. slightly enlarged), developed (vs. rudimentary) nuchal crest in males, 2–4 (vs. 8–10) upper dorsal scale rows on the lateral body directed upward along the body, relatively small tympanum with less than half diameter of orbit (vs. relatively large with more than half diameter of orbit). In addition, Bronchocela celebensis is distinguished from other congeners by having the following combination of characters: adults reach maximum SVL 119.0 mm in males and 105.9 in females, orbital area and tympanum with the same colour as body, ventral scales arranged in 10–12 rows, 50–76 mid body scale rows, 10–12 lanceolate nuchal crest scales, 62–78 ventrals, 33–35 lamellae on fourth toe, third finger longer than the fourth; mid gular scales not enlarged, abdominal scales acuminated and enlarged compared to pectoral, non-enlarged and keeled temporal scales with 7 or 8 rows between orbit and tympanum.

TAL/SVL 3.0–3.6 (n =3) 3.2–3.7 (n =13) Tail broken 3.3–3.6 (n =3)

supralabials 9–10 9, 10

infralabials 8–10 9, 10

scales from eye to tympanum 7, 8 7, 8

nuchal crest scales 8–10 8–10

subdigital lamellae on toe IV 32–34 31–33

midbody scale rows 50–62 52–76 54–56 57–60 ventrals 64–72 62–78 78–80 75–79

Redescription of holotype. An adult female, SVL 102.4 mm. Head moderately large, elongate, HL 28.0% of SVL, narrow, subtriangular in dorsal and ventral aspects, HW 58.9% of HL; distinct from neck; snout elongate, snout length greater than eye diameter, ED 77.1% of ES; interorbital distance broad; eye large, pupil rounded; diameter of eyes slightly greater than eye-tympanum distance, TYE 92.6% of ED; ear opening shallow, its greatest diameter horizontally, tympanum smaller than orbit, nearly 40% of orbit diameter; tympanum surrounded by keeled scales; four or five temporal scales enlarged, keeled, juxtaposed, seven or eight scale rows between orbit and tympanum; forehead concave; scales on interorbital and supercilium area keeled; scales on snout feebly keeled, larger in size than those of occipital region; a developed nuchal crest continuing dorsally as a dorso-nuchal crest; dorsal crest rudimentary, consisting of 10 scales up to the level of axilla, no crest on the tail; rostral scale width greater than its height, ventro-posteriorly in contact with first supralabial, contacting posteriorly four more or less equal-sized postrostral scales; around nostrils on each side two supranasals, two postnasals, a single prenasal, and two subnasals, which separate the nasal from the supralabials; nostrils round located in the middle of the undivided nasal plate; canthus rostralis and supraciliary edges blunt; three canthal scales between supranasal and anterior margin of orbit; no distinct parietal plate; mental subtriangular, flat posteriorly, shorter than wide, posterior-laterally in contact with two enlarged postmentals separated by a smaller scale; each postmental pair bordered posteriorly by three or four smooth scales, including the medial scale, but exclusive of infralabials; chin scales keeled; gular pouch present, midgular scales not enlarged; throat scales and midgular scales keeled, mucronate, and imbricate; three scale rows separate orbit from supralabials; supralabials nine (seventh in midorbit position); infralabials eight, decreasing in size toward gape.

Body slender; lateral body scales large, equal, strongly keeled and imbricate; scales on lateral body slightly smaller than on the venter at same level, directed backward and downward anteriorly and directed straight backward posteriorly; lateral body scales on the posterior body slightly larger than the anterior body scales; 2–4 upper dorsal scale rows directed backward and upward along the body; 50 scales around the midbody; pectoral scales and abdominal scales keeled, mucronate, imbricate and keels forming regular and parallel continuous ventral ridges; abdominal scales slightly larger than pectoral scales; 10–12 rows enlarged ventrally, without clear margin with the lateral scales; 70 ventrals.

Forelimbs moderately short; no oblique fold (pit) present on shoulders, but shoulder scales keeled and smaller; dorsal scales on fore- and hind limbs keeled, enlarged, imbricate and mucronate; ventral scales on upper arm and lower arm keeled, imbricate, and mucronate; hind limbs relatively longer than forelimbs; scales on ventral surface of thigh keeled, enlarged, imbricate and mucronate; tibia comparatively longer than femur; keels on tibia forming a series of continuous parallel ridges; digits elongate, slender; relative length of digits (fingers) 4> 3> 2> 5> 1; (toes) 4> 3> 5> 2> 1; all bearing slightly recurved, sharp and elongate claws; subdigital lamellae entire, bicarinate, and regular, 34 (left) subdigital lamellae on toe IV.

Tail elongated and complete, 355.0 mm. Ventral scales on tail base keeled and imbricate, smaller in size than on dorsal tail; dorsal scales on tail enlarged, imbricate, keeled, mucronate, and keels forming continuous parallel ridges; tail with subcaudals on median row not enlarged, subequal, imbricate, keeled, and mucronate.

Colouration.–– In preservative, colours faded and dorsum pale purplish gray due to colour having been bleached with time.

In life, dorsum dull green; mostly uniform body colour with scales edged dark, some individuals with few brown markings on the lateral body; nuchal spines yellowish or brownish; orbit and labials pale, tympanum whitish; knee, elbow, wrist, heel dark brownish; dorsal fingers and toes, posterior 2/3 rd of the tail brown; ventral head, body, limbs, anterior tail, and mid gular lighter green.

Habitat, natural history, and distribution. This species is usually found in closed canopy areas in primary forests (mostly forest edge) or rarely in undisturbed secondary forests, but avoids open areas. We often found it at the ecotone of forests and other vegetation (e.g., plantations, well-maintained home gardens etc.) while basking (from sunrise until midday), usually 1.5 to 4 meters above the ground. Like other Bronchocela species, it is usually active during the daytime, mostly around 0900 hr. At night, the adults prefer higher branches of the trees to sleep, mostly in open canopy areas, while juveniles prefer tiny branches of shrubs at lower heights.

The species is sympatric with other arboreal agamids such as Draco iskandari , D. spilonotus , and D. supriatnai , but allopatric with Bronchocela cristatella . We always found several individuals of B. celebensis close together at higher elevations (usually above 900m above sea level), and never at lower elevations where B. cristatella sensu lato is usually distributed on the adjacent islands of southern Sulawesi. Most of the individuals were observed at Donggala Regency and Sigi Regency in Central Sulawesi, and Mt. Klabat, Minahasa regency in North Sulawesi. However, we have observed a lower number of adult males (male:female ratio = 1:4), and this is an unusual phenomenon compared to other Bronchocela species. It is probably due to the impact that the illegal pet trade which accelerates the removal of healthy adult males from their natural habitats. Because the males have prominent nuchal crests and brighter colours compared to females. The southern margin of the distribution of this species is Polewali Regency in West Sulawesi, and it seems the distribution records are scattered ( Fig. 1 ) due to forest fragmentation, but always confined to forested uplands. This species has never been reported from Southeastern parts of Sulawesi.

Conservation status. The habitats of Bronchocela celebensis are highly fragmented. The application of the IUCN Red List criteria ( IUCN Standards & Petitions Subcommittee 2019) with the updated distribution data shows that B. celebensis is restricted to an area of occupancy (AOO) of 224 km 2 recorded from 13 localities (10 locations) within 92,520 km 2 extent of occurrence (EOO). Given the low area of occupancy, the scattered distribution of severely fragmented forests, considerable number of individuals available in local pet trade (wild catch) for low price (IDR 400,000 = USD 27), consequence lower number of adult males observed in the natural habitat, B. celebensis should be considered as a “Vulnerable” (VU) species.

Figures

FIGURE 1. Current distribution map showing the collection/observation localities of Bronchocela celebensis (red) and its allopatric congener, B. cristatella sensu lato (blue) on adjacent islands of southern Sulawesi.

FIGURE 4. Bronchocela celebensis holotype (NHMUK 1946.8.11.48, adult female) from Sulawesi, Indonesia: (A) lateral view of the anterior body, (B) dorsal head, (C) lateral head, (D) ventral head.