Brookesia tristis, 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 : 12-15

Brookesia tristis sp. n.

ZooBank LSID: urn:lsid:zoobank.org:act:56F36D4D-1F94-49C4-AC30-6E894B6AA998

Remark.—This species has been considered before as Brookesia sp. ‘‘Montagne des Francais’’ [ 7] and as Brookesia sp. nov. [ 37].

Holotype.— ZSM 1704 /2004 (no field number), adult male (hemipenes everted), collected at Montagne des Français , 12°19'S, 49°20'E, ca. 150 m a.s.l., Antsiranana Province, northern Madagascar, on 23 February 2004 by F. Glaw, M. Puente, R. D. Randrianiaina and guides of the hotel ‘‘ King’s Lodge’ ’.

Paratypes.— UADBA uncatalogued ( FGZC 477–478), ZSM 357/2004 ( FGZC 654) [not examined morphologically], and ZSM 876/2010 [no field number, not examined morphologically], adult males, ZSM 354 /2004 ( FGZC 651 ), adult female, same data as holotype ; ZSM 1705 /2004–1707/2004 (no field numbers), three adult females, most likely same data as holotype . UADBA uncataloged ( FGZC 1187, 1189, 1191); ZSM 2146–2149 /2007 ( FGZC 1188 , 1190 , 1192 , 1193 ), adult females, all collected at Montagne des Français , near remains of French Fort, 12°19'S, 49°20'E, 250–300 m a.s.l., Antsiranana Province, northern Madagascar, on 27 February 2007 by P. Bora, H. Enting, F. Glaw, A. Knoll and J. Köhler; ZSM 2018 /2008 ( FGZC 1733 = MgF 061) and UADBA uncatalogued ( FGZC 1734 = MgF 061), collected at Montagne des Français , canyon 2 km [air distance] W of Andavakoera, 12°19,838'S, 49°20,941'E, 250 m a.s.l., on 24 January 2006 by E. Randriamalala; UADBA uncatalogued ( FGZC 1657), female, ZSM 1505 /2008 ( FGZC 1656 ), adult male (hemipenes everted), both collected ca. 1.5 km southwest of Andavakoera (‘‘ Frontier base camp’’), 12°19'59.2"S, 49°21'20.6"E; 140 m a.s.l., Montagne des Français, Antsiranana Province, northern Madagascar, on 16 February 2008 by M. Franzen, F. Glaw, J. Köhler and Z.T. Nagy.

Diagnosis.— A member of the Brookesia minima group based on small body size (SVL <24 mm) and molecular phylogenetic relationships. Brookesia tristis 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 presence (in most specimens) of lateral spines on the tail (vs. absence); from B. exarmata by presence (in most specimens) of lateral spines on the tail (vs. absence); from B. karchei by probably smaller adult body size (female SVL 18.0– 23.8 mm vs. 30.7 mm; no measurements of clearly identified males available for B. karchei ), and absence of a supraocular cone (vs. presence); from B. minima by the presence of a supranasal cone, a pelvic spine, and (in most specimens) lateral spines on the tail (vs. absence), and hemipenis with small apical spine-like papillae (vs. balloon-like without ornaments); from B. peyrierasi by smaller adult body size (male SVL 18.0– 18.2 mm vs. 19.7–22.4 mm), presence (in most specimens) of lateral spines on the tail (vs. absence), and by a hemipenis with small apical spine-like papillae (vs. bilobed hemipenis with four large spines per lobe); from B. ramanantsoai by smaller adult body size (male SVL 18.0– 18.2 mm vs. 21.7 mm), absence of a supraocular cone (vs. presence in some specimens), presence (in most specimens) of lateral spines on the tail (vs. absence), and hemipenis with small apical spine-like papillae (vs. hemipenis balloon-like without ornaments); and from B. tuberculata by the absence of a supraocular cone (vs. presence), presence (in most specimens) of lateral spines on the tail (vs. absence), and hemipenis with small apical spine-like papillae (vs. hemipenis with apical crown-like structure). For a distinction from B. confidens , B. desperata , and B. micra , described below, see the diagnoses of these species. Referencing a fragment of the 16S rRNA gene, B. tristis shows an uncorrected pairwise divergence of 6.4% to its sister species B. desperata , and divergences>6.9% 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, and a crest at the posterior edge of the head, that form a weakly developed dorsal helmet; a pair of curved parasagittal crests that start above the eyes and begin to converge before terminating at the posterior crest; between the parasagittal crests there is a second pair of parallel longitudinal crests; three pointed tubercles on each side of posterior helmet crest, one at termination point of lateral crest, one at termination point of parasagittal crest, and 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 does not project beyond snout tip; head longer (5.1 mm) than wide; chin and throat without longitudinal rows of slightly enlarged tubercles. Dorsal surface of body without a vertebral ridge or keel; 11 dorsolateral pointed tubercles form a complete longitudinal line on the body; 10th dorsolateral tubercle least pointed, small; most posterior (11th) pointed dorsolateral tubercle being largest, above insertion point of hindlimb, very slightly projecting backwards; pointed dorsolateral tubercles almost equally spaced, 3rd to 6th tubercle slightly larger than others, pointing out almost perpendicularly from body; slightly enlarged, rounded tubercles form curved transversal crests on either side of the vertebral line between 1 st and 10th dorsolateral pointed tubercles; dorsal surface of tail with slightly enlarged rounded tubercles forming separated rounded crests that continue from tailbase to two-thirds down the tail; no well-defined dorsal pelvic shield in sacral area; lateral surface of body with evenly spaced enlarged rounded tubercles, mainly arranged in four longitudinal rows; 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 tail tip; no enlarged tubercles on ventral surfaces of tail. In life, colouration of head, body, limbs and tail brown to beige. Faint brown bars radiate from eye to lateral surfaces of head; chin and throat brown; ventral surfaces of body and tail pale brown. After almost seven 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 preservative, most paratypes are dorsally darker than the holotype, ranging from brown to dark brown. Their ventral surface is greyish except for the region of the chest, which shows brown mottling. In life several specimens got a light grey vertebral stripe when kept together with conspecifics in a bag, suggesting that this might be a stress colouration. The life colouration of juveniles generally resembles that of adults. The tail base of the females is distinctly less thickened than in the males. In life, two adult specimens had a weight of 0.18 g and 0.206 g, respectively.

Genital morphology.— Only two specimens with everted hemipenes were available for examination: ZSM 1505/2008 and ZSM 1704/2004 (holotype). In both specimens, one hemipenis is clearly incompletely everted whereas the second one appears fully everted, although this cannot be stated with complete certainty. In ZSM 1505/2008, hemipenis length is 2.5 mm and maximum hemipenis width is 1.7 mm when fully turgid. The hemipenis is an irregular tubular structure without any ornaments, which in fully turgid state is somewhat balloon-shaped, widest at the central part of the truncus and more narrow at the pedicel and apex. Near the apex, two very small lobe-like structures are visible, corresponding to attachments of the retractor muscle, and a few very small spinelike papillae. However, it is not clear whether the hemipenis could possibly become further everted and then may become more strongly bilobed terminally, with a more prominent exposure of the spine-like papillae. There are no ornaments on pedicel and truncus, and no recognizable ornamental structures on apex (although apex might not be fully everted; Fig. 6 ).

Etymology.— The species epithet is an adjective derived from the Latin ‘‘tristis’’ meaning ‘‘doleful’’, ‘‘sad’’, ‘‘sorrowful’’, and refers to the fact that the entire known range of this species (Montagne des Français) suffers from severe deforestation and habitat destruction [ 37] despite recently being declared as a nature reserve.

Distribution.— Only known from the Montagne des Français limestone massif.

Natural History.— Most individuals of B. tristis were found roosting at night on small branches about 5–50 cm above the leaf litter within a limestone massif with deciduous dry forest. By far most specimens were found in a few small areas where the species was abundant, whereas it was rare in other, apparently similar habitats. One of the females laid two large eggs (5.9 6 3.7 mm resp. 5.8 6 3.5 mm diameter) in February. The two juveniles hatched 64 and 69 days after egg deposition at temperatures between 20– 26°C. They measured 14 mm in total length. Eight days after hatching the weight of the older juvenile was 0.03 g.

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