Draco guentheri

Excerpt from:

Phylogenetic Systematics, Scaling Relationships, and the Evolution of Gliding Performance in Flying Lizards (Genus Draco)
Copyright by Jimmy Adair McGuire 1998

Draco guentheri Boulenger, 1885:257; pl. 20, fig. 2. Type–locality: "Philippine Islands" (holotype: BM 79.4.16.4).
Draco rizali Wandolleck, 1900:15.
Draco volans reticulatus Hennig, 1936:179.
Draco volans Inger, 1983:8.

Diagnosis.—The following diagnosis applies to all of the specimens of Draco guentheri that we have examined except for two specimens collected near the Malagos Eagle Station, Davao Province, Mindanao. These two specimens differ from all other specimens examined in a number of key characters and may warrant taxonomic recognition once larger samples are collected and geographic variation is better understood (see comments section below).

Draco guentheri can be distinguished from all other species of Draco in the Philippines by the following combination of characteristics:
(1) moderately large size (maximum SVL of males = 85 mm [n=8], females = 97 mm [n=9]);

(2) nostrils oriented laterally on the snout;
(3) enlarged, thornlike superciliary scale present;
(4) dorsal scales variable in size, often with strong keeling;
(5) presence of large, unscaled tympana;
(6) six or occasionally seven ribs supporting patagium;
(7) lacrimal bone absent;
(8) large black postrictal ocellus surrounding an enlarged white tubercle absent;
(9) dorsal patagial coloration of males dark green with numerous spots of bluish or yellow–green, outer margin salmon (Taylor, 1922);
(10) dorsal patagial coloration of females black, with slight gray wash, enclosing bright reddish to orange spots (Taylor, 1922);
(11) in males, ventral surface of patagium salmon or brick red, usually with only one dark spot near outer margin (Taylor, 1922);
(12) in females, ventral surface of patagium light yellow, with variable numbers of small dark spots;
(13) males with triangular dewlap, bright purple or reddish with bright yellow tip (Taylor, 1922; Gaulke, 1993);
(14) malachite green dorsal body coloration in males; females body coloration metallic, iridescent gray (Taylor, 1922b);
(15) males with orbital region heavily suffused with dark pigments.

Draco guentheri can be distinguished from all other species of Philippine Draco except D. ornatus on the basis of the malachite green dorsal body coloration of males. Draco guentheri can be distinguished from D. jareckii, D. mindanensis, D. ornatus, D. quadrasi, and some populations of D. spilopterus based on its unscaled (versus scaled over) tympana. It can be further distinguished from D. bimaculatus, D. jareckii, D. mindanensis, D. ornatus, D. palawanensis, D. quadrasi, and D. spilopterus based on the presence (versus absence) of an enlarged, thornlike superciliary scale. It can be further distinguished from D. bimaculatus and D. mindanensis based on the number of ribs supporting the patagium (six versus five). It can be further distinguished from D. mindanensis based on the orientation of the nostrils (oriented laterally versus posterodorsally) and in the absence (versus presence) of a lacrimal bone.

Description.—A moderately large species, maximum observed SVL in males = 85 mm, females = 97 mm; dorsal head scales small to medium–sized, heterogeneous, variably keeled or rugose; rostral 1–3 times wider than high, bordered by 4–7 postrostrals; internasals, frontonasals, and prefrontals small except for a series of enlarged, strongly keeled scales arranged in shape of inverted "Y", the base originating a few scales posterior to rostral, arms contacting supraorbitals; supraoculars granular laterally, grading to much larger size medially such that medialmost supraoculars almost as large as parietals; frontoparietals and parietals much larger than scales of snout; interparietal slightly smaller, equal, or slightly larger than surrounding parietals, usually (10 of 16) with opalescent lens; nasals turretlike, pierced centrally by external nares, nares point laterally and slightly dorsally; 3–4 canthals, strongly keeled; anterior superciliaries elongate, keeled; posterior superciliaries granular except for usual presence of large, laterally compressed thornlike superciliary scale (see comments below), usually taller than wide; loreals and lorilabials immediately superior to supralabials relatively large, remaining loreals and lorilabials much smaller, juxtaposed, only slightly larger than adjacent palpebrals; an enlarged scale, usually wider than tall usually present immediately superior to posteriormost supralabial; one to several pre–, sub–, and postoculars may be enlarged forming discontinuous subocular series, remaining postoculars granular; a series of 2–3 large keeled scales extending posteriorly from posterior border of orbit; supralabials 7–12, pentagonal or with anterior border convex, posterior border concave, 1–4 times longer than tall, anteriormost supralabial usually much smaller than others, posteriormost supralabial usually longest; infralabials 9–13, pentagonal; tympanum usually unscaled (see comments below), surrounded by granular scales, a large tubercle present a few scales anterior to tympanum; scales surrounding corner of mouth granular; remaining temporals, occipitals, and nuchals granular except for 1–2 tubercles superior to tympanum midway between tympanum and nuchal crest and 2–4 tubercles posterior and slightly superior to tympanum immediately posterior to underlying quadrate bone; mental bordered by 3–5 postmentals; gular scales and scales of dewlap and ventral surfaces of throat lappets granular, scales of dorsal surfaces of throat lappets enlarged distally; dewlap scales of males enlarged at distal extremity.

Dorsal body scales small, slightly imbricate, variably keeled; a midvertebral nuchal crest composed of laterally compressed dorsal scales present, comprised of 10–22 scales in males, 5–23 scales in females; lateral nuchal crests present in both sexes; middorsals 2–4 times larger than scales of lower flanks, patches of slightly enlarged scales surrounding 1–3 much larger, keeled scales present along flanks near proximal edge of patagia, part of discontinuous series of enlarged keeled scales extending from lateral nuchal crests, along base of patagium, to sacral region; a conspicuously enlarged series of keeled paravertebral scales rarely evident; caudals strongly keeled; paired, enlarged middorsal caudals extending length of tail; paired, enlarged, subcaudals extending length of tail; over proximal approximately 10% of tail, lateral caudals strongly keeled forming weak fringe; dorsal patagium with juxtaposed scales, variably keeled, keels arranged into linear series that extend parallel to axis of body; ventral patagium with flat, delicate scales, variably keeled; ventral body scales strongly keeled, approximately equal in size or smaller than largest dorsals; brachials imbricate, variable in size and degree of keeling; prebrachials about equal to largest dorsals in size, moderately or strongly keeled, grading smoothly into smaller keeled suprabrachials; postbrachials much smaller than other brachials, weakly keeled or unkeeled; infrabrachials weakly keeled, approximately equal to postbrachials in size, much smaller than suprabrachials; antebrachials slightly larger than brachials, variably keeled, juxtaposed or weakly imbricate; infra–antebrachials smaller than other antebrachials; infracarpals granular, keeled or mucronate, proximal subdigital lamellae with 2–4 keels, distal subdigital lamellae with 1 keel; femorals highly variable in size and degree of keeling; prefemorals, anterior suprafemorals larger than dorsals, strongly keeled; posterior suprafemorals granular, unkeeled; postfemorals granular, variably keeled, keels directed posteriorly rather than distally; infrafemorals much smaller than ventrals, keeled; a series of enlarged, flaplike posterior infrafemorals forms conspicuous fringe along posterior edge of upper hind limb, continues along posterior edge of proximal half of lower hind limb; tibials keeled, small proximally and distally, equal to dorsals in size elsewhere, pretibials largest; infratarsals strongly keeled or mucronate, much smaller than supratarsals, proximal subdigital lamellae with 2–4 keels, distal subdigital lamellae with 1 keel, 25–31 subdigital lamellae on fourth toe. Patagia usually supported by 6 ribs (16 of 17), occasionally 7 (2 of 17); pleurodont teeth usually 7 (10 of 16), sometimes 6 (6 of 16); lacrimal bone absent.

Coloration in life.—Because the only live Draco guentheri that we have examined were males, the following color description will be more detailed for males than females. A detailed description of the female color pattern is available in Taylor (1922a) and we have included relevant aspects of his description following our description of male coloration. The dorsal coloration of free–living males is vivid malachite green. Unfortunately, this coloration rapidly fades to brown when the animals are handled and our color photographs (and thus our color illustrations) failed to capture the true nature of this coloration. In our sample, the green dorsal coloration of males is mottled with tan, white, and scattered flecks of black. The sides of the head and neck (including the dorsal surfaces of the neck lappets) are vivid green with many small black spots. The tail is banded with dark brown. The limbs are mottled with brown and green overlain with white spots. Forelimb banding is restricted to the fingers and hindlimb banding is present on the toes only. The orbital region is suffused with black pigments, excepting only the ciliaries, which are ultramarine blue. A large interorbital spot is present, but as in most members of the Draco volans group, males lack a nuchal spot. The ventral surface of the body and limbs is off–white; the ventral surface of the tail is salmon. The gular coloration is bright light green overlain with a dark green reticulum. The proximal one–fourth of the dewlap is vibrant green with closely set, fine black speckling; the remainder of the dewlap is immaculate green, although the distalmost one–fourth grades to white in some individuals (but see comments section below). The dorsal patagium is green, scattered with large paler green spots. Two or three black marginal blotches are present, separated from one another by green bars that overlay the ribs. One or a few green spots are visible within each black marginal patch where black pigments are lacking. The ventral patagium is buffy or pale green (see comments below), with one to several melanic spots present near the patagial margin. In some individuals, extensive black ventral spotting is present. Taylor (1922a) described D. guentheri (as D. rizali) females as follows: dorsal coloration "metallic, iridescent gray, with dim, narrow, blackish reticulations, sometimes forming dim, irregular, brownish bands across back... shoulders with or without a greenish wash." The tail has dark brown bands on a paler brown base color. Taylor noted the presence of melanic interorbital and nuchal spots, dark markings or reticulations on the side of the head, and radiating lines from the eye. The ventral coloration is cream–white with the gular region reticulated with bluish. The dorsal patagium is described as "black, slightly washed with gray, enclosing bright reddish to orange spots" that are lightest nearer to the body and deeper red near the patagial margin. The ventral surface of the patagium is lightly washed with yellow, salmon, or red, with several small black spots near the anterolateral border. In some individuals, small black spots may be scattered over the entire ventral surface of the patagium.

Distribution.—Draco guentheri specimens are known from Mindanao, Basilan, Jolo, Siminor, Sanga Sanga, Siasi, and Bongao (Figure 1.4; Taylor, 1922; Gaulke, 1993). Taylor referred to D. guentheri (as D. rizali) as the common Draco of the Sulu Archipelago and it therefore seems likely that the species occurs on other islands within the archipelago, particularly the larger islands such as Tawitawi.

Natural History.—Little is known about the natural history of Draco guentheri. We found this species in second growth forest and on coconut trees adjacent to secondary forest near the Malagos Eagle Station, Mindanao. At this site, D. guentheri was in sympatry with D. bimaculatus, D. cyanopterus, and D. mindanensis. As Taylor (1918, 1922) indicated that D. guentheri is the common species of the Sulu Archipelago, it seems likely that the species occurs in open coconut groves, particularly in regions where D. cyanopterus is absent.

Comments.—Draco guentheri is known primarily from the Zamboanga region of Mindanao and from the Sulu Archipelago. Taylor (1922) and Gaulke (1993) both based their descriptions (as D. rizali and D. reticulatus, respectively) on specimens from these regions and most of the specimens that we have examined were collected in these areas. However, we have two male specimens collected near the Malagos eagle station, Davao Province, from the eastern portion of Mindanao. The Malagos specimens differ from the western specimens both in features of theirscalation and coloration, but they are clearly closely related to this species. The Malagos specimens both have the tympana covered with small scales, whereas all of our material from Zamboanga, Jolo, and Siminor Islands have large, completely unscaled tympana. The Malagos specimens also lack the enlarged thornlike superciliary scale that is characteristic of all other D. guentheri we have examined. Like the Zamboanga and Sulu Archipelago specimens, the Malagos males were vivid malachite green in life which clearly distinguishes them from all other Philippines Draco. However, the dewlaps of the Malagos males were bright green and the ventral surfaces of the patagia were pale green, whereas Taylor (1922) and Gaulke (1993) describe the dewlap as bright purple or reddish with a bright yellow tip and the ventral surfaces of the patagia as salmon or brick red. Although we have noted several characteristics that appear to distinguish eastern and western D. guentheri, taxonomic adjustment would be premature at this time given that we have seen only two males (and no females) from eastern Mindanao.

Range Map: