Brookesia confidens, Frank Glaw & Jörn Köhler & Ted M. Townsend & Miguel Vences, 2012

Frank Glaw, Jörn Köhler, Ted M. Townsend & Miguel Vences, 2012, Rivaling the World’s Smallest Reptiles: Discovery of Miniaturized and Microendemic New Species of Leaf Chameleons (Brookesia) from Northern Madagascar, PLoS ONE 7 (2), pp. 1-24 : 15-16

Brookesia confidens sp. n.

ZooBank LSID: urn:lsid:zoobank.org:act:CB2A9146-0161-42B7-A145-6DED579F1F21

Remark.—This species has been considered before as conspecific with Brookesia sp. ‘‘Montagne des Francais’’ [ 7].

Holotype.— ZSM 2150/2007 ( FGZC 1196 ), adult male (hemipenes incompletely everted), collected on trail to the ‘‘Petit Tsingy and Grotte des Chauves-Souries’’ , 12°57'25"S, 49°0 7'0 6"E, 90 m a.s.l., Ankarana National Park , Antsiranana Province, northern Madagascar, on 1 March 2007 by P. Bora, H. Enting, F. Glaw, A. Knoll, and J. Köhler.

Paratypes.— UADBA uncatalogued ( FGZC 1194–1195), two specimens; ZSM 2151/2007 ( FGZC 1197), probably male, ZSM 2152/2007 ( FGZC 1198), adult female, ZSM 2153/2007 (FGZC 1199), adult female, all with same data as holotype; UADBA uncatalogued ( FGZC 1608), UADBA uncatalogued ( FGZC 1610), ZSM 1511/2008 ( FGZC 1607), adult female, ZSM 1512 /2008 ( FGZC 1609 ), adult male, all collected at ‘‘ Petit Tsingy’ ’, Ankarana National Park, Antsiranana Province, northern Madagascar, on 12 February 2008 by N. D’Cruze, M. Franzen, F. Glaw and J. Köhler.

Diagnosis.— A member of the Brookesia minima group based on small body size (SVL<23 mm) and molecular phylogenetic relationships. Brookesia confidens is distinguished from other members of the group as follows: from B. dentata by probably smaller adult body size (no measurements of male B. dentata available), and absence of a supranasal cone (vs. presence); from B. exarmata by the absence of a supranasal cone (vs. presence); from B. karchei by a smaller adult body size (female SVL 20.6–22.6 mm vs. 30.7 mm; no measurements of clearly identified males available for B. karchei ), and absence of a supranasal cone (vs. presence); from B. minima by a very narrow hemipenis (vs. balloon-like); from B. peyrierasi by generally smaller adult body size(male SVL 18.3– 20.1 mm vs. 19.7–22.4 mm), the absence of a supranasal cone (vs. presence), absence of a supraocular cone (vs. presence), and very narrow ornamentless hemipenis (vs. massive, bilobed hemipenis with four spines per lobe); from B. ramanantsoai by a smaller adult body size (male SVL 18.3–20.1 mm vs. 21.7 mm), absence of a supranasal cone (vs. presence), absence of a supraocular cone (vs. presence in some specimens), and hemipenis very narrow (vs. balloon-like); from B. tuberculata by the absence of a supranasal cone (vs. presence), absence of a supraocular cone (vs. presence), and hemipenis very narrow with pustules on apex (vs. wider, with crown-like apical structure). The new species is most similar to B. tristis but differs from this species by indistinct and short parasagittal crests (vs. distinct) and by 13 dorsolateral pointed tubercles (vs. 11), and ornamentless apical region of hemipenis (vs. spine-like papillae on apex). For a distinction from B. desperata and B. micra , described below, see the diagnoses of these species. Referencing a fragment of the 16S rRNA gene, B. confidens shows an uncorrected pairwise divergence of 6.7% to its sister species B. tuberculata , and divergences>9% to all other species of the B. minima group.

Description of holotype.— Adult male in good state of preservation ( Fig. 7 ; Supporting Information S1). Both hemipenes everted. Measurements in Table 1. Head with lateral crest starting at median level at the posterior edge of eye; prominent orbital crests with distinctly enlarged pointed tubercle at posterior level slightly below lateral crest, and a crest at the posterior edge of the head, that form a weakly developed dorsal helmet; a pair of very short straight parasagittal crests that transform posteriorly into a broad area of elevated scales which almost cover the entire posterior head surface; three pointed tubercles on each side of posterior helmet crest, a prominent one at termination point of lateral crest, an even larger one at the imaginary termination point of parasagittal crest, and a weakly developed one between parasagittal and lateral crests; one pointed tubercle on lateral surface of head, below lateral crest in temporal region; orbital crest denticulated; no supraocular cone recognizable; supranasal cone not clearly recognizable; head longer (5.3 mm) than wide; chin and throat without longitudinal rows of slightly enlarged tubercles. Dorsal surface of body without a vertebral ridge or keel; 13 dorsolateral pointed tubercles form a complete longitudinal line on the body; most posterior (13th) pointed dorsolateral tubercle being largest, above insertion point of hindlimb; pointed dorsolateral tubercles almost equally spaced, pointing out almost perpendicularly from body; slightly enlarged, pointed tubercles form curved transversal crests on either side of the vertebral line between 2nd and 10th dorsolateral pointed tubercles; slightly enlarged tubercles on dorsal surface of tail, without any reconizable pattern; no well-defined dorsal pelvic shield in sacral area; few irregularly scattered enlarged rounded ubercles on the lateral surface of body; venter without enlarged tubercles; scattered, soft-pointed tubercles on limbs; no pointed tubercles around cloaca; longitudinal row of slightly enlarged pointed tubercles lateral on tail, forming a longitudinal row from tail base to two-thirds of tail length; no enlarged tubercles on ventral surfaces of tail. After almost four years in ethanol, all surfaces pale grey to beige, with most pointed tubercles being brown; upper surface of head pale brown.

Variation.— For morphological measurements and proportions see Table 1 and Supporting Information S1. In ZSM 2153/2007, the ground colour is dark brown with a whitish vertebral stripe that starts at posterior half of body and extends onto the tail which is entirely beige with scattered brownish spots. The posterior dorsal surface of head is grey. The body of ZSM 1512/2008 is light grey whereas the head is brown with a greyish transverse line between the nostrils. The tail base of the females is less thickened than in the males. In life, all individuals with dorsal colouration of head, dorsum and tail light grey or pale beige, lateral parts of the body brown, with indistinct greyish marbling lateroventrally and with few small dark brown spots around the flank tubercles; limbs almost uniformly dark brown. This pattern is likely a stress colouration.

Genital morphology.— For this species, everted hemipenes are available only for the holotype (ZSM 2150/2007). On both sides, the organs are single tube-like structures of low diameter which decreases from the apex to the distal part of the truncus. The left hemipenis is not fully everted whereas the one on the right side (length 1.3 mm; width at the pedicel 0.6 mm, width at the apex 0.4 mm) might be fully everted, but this cannot be verified without examination of further material. There are no ornaments on the pedicel and truncus. The sulcus spermaticus is not recognizable on most of the truncus but becomes more distinct in the apical region. The apical region is characterized by a slight increase in diameter but not bilobed, and is covered by relatively large but poorly defined pustular papillae ( Fig. 6 ). The hemipenis is devoid of any further prominent structures such as the spiny apical papillae of B. peyrierasi (which are visible also in incompletely everted organs).

Etymology.— The species epithet is an adjective derived from the Latin ‘‘confidens’’ meaning ‘‘confident’’, ‘‘trusting’’. The known range of the species is supposedly a well protected nature reserve with apparently limited habitat destruction. Furthermore, this area might benefit from natural protection by the tsingy limestone formations which are difficult to access, thus giving hope for the species’ survival.

Distribution.— Only known from a single locality within Ankarana National Park.

Natural History.— Most individuals were found roosting at night on thin branches about 5–20 cm above the leaf litter in deciduous dry forest close to a small forest trail within a small area, surrounded by tsingy outcrops. At this locality, the species was relatively abundant, whereas it was not found at similar localities nearby, suggesting a patchy distribution and a preference for certain microhabitats. This hypothesis is also supported by the fact that earlier herpetological surveys in Ankarana [38,39], did not record any species of the Brookesia minima group.

When stressed, individuals can quickly change colour and display a broad pale vertebral stripe contrasting with the darker flanks.

Figures

Figure 6. Hemipenes of species in the Brookesia minima group. The photos show for each species, a general view of the organs and a close-up. For B. desperata, the inset picture shows a non-turgid everted hemipenis where the two apex projections are very prominent. Note that also several other of the shown preparations are not fully turgid, especially in B. ramanantsoai and B. micra. In two other species (B. confidens and B. tristis) the shown hemipenes might not be fully everted. doi: 10.1371 / journal. pone. 0031314. g 006

Figure 7. Dorsal, lateral and ventral views of preserved male holotypes of newly described species. Scale bar equals 5 mm. doi: 10.1371 / journal. pone. 0031314. g 007