Madagascarophis lolo, Sara Ruane, Frank T. Burbrink, Bernard Randriamahatantsoa & Christopher J. Raxworthy, 2016

Sara Ruane, Frank T. Burbrink, Bernard Randriamahatantsoa & Christopher J. Raxworthy, 2016, The Cat-eyed Snakes of Madagascar: Phylogeny and Description of a New Species of Madagascarophis (Serpentes: Lamprophiidae) from the Tsingy of Ankarana, Copeia 104 (3), pp. 711-721 : 716-719

Madagascarophis lolo , new species

urn:lsid:zoobank.org:act: E94496 B3-AC04-4FE2-AFA6- 8CC7DBE3A63A

Figures 1̡ 2̡ 3̡ 4̡ 5; Table 1

Holotype.— AMNH 176422 ( RAX 12626 ), adult male (Fig. 1), Madagascar, Antsiranana Province, Diana Region, Ankarana National Park, ~ 4 km northwest of the village of Mahamasina, tsingy karst trail , 102 m elevation, 49.11507°E, 12.94210°S, 9 February 2014, 1930 hours, B. Randriamahatantsoa, C. Raxworthy, S. Ruane.

Diagnosis.— A new species of Madagascarophis than can be diagnosed from its congeners by the following combination of characters: an overall gray body color with a black vertebral stripe and alternating light gray blotches down the dorsum, 25 scale rows at midbody, 189 ventral scales and 56 divided subcaudal scales, with extended contact of the posterior inframaxillary scales. Madagascarophis lolo ̗ new species, differs from all other species of Madagascarophis having a gray body color combined with an alternating pattern of pale gray blotches along the vertebral column and the presence of black scales on the vertebral row scales, giving the appearance of a thin black dorsal stripe (Figs. 1, 3, 4). This overall combination of color and pattern is unique among species of Madagascarophis (see Domergue, 1987:fig. 4 for comparison). Madagascarophis lolo ̗ new species, differs from all other species with the exception of M. fuchsi by having extended contact of the posterior inframaxillary scales ( Fig. 5 ). We note the specimen of M. lolo ̗ new species, has a single gular scale that infringes on the posterior end of the posterior inframaxillaries. However, with the exception of M. fuchsi , the posterior inframaxillary contact of M. lolo ̗ new species, is still much greater than for the other species of Madagascarophis ( Fig. 5 ; see Glaw et al., 2013a for additional examples).

Madagascarophis lolo ̗ new species, differs from M. fuchsi by having a lower number of infralabial scales (10 M. lolo vs. 12– 13 M. fuchsi ) and a higher ventral scale count (171–174 M. fuchsi vs. 1 8 9 M. lolo ). However, this 1 5 ventral scale difference falls within the intraspecific range of other species (e.g., 35 ventral scales in M. meridionalis ). It differs from the other species of Madagascarophis except M. colubrinus by having a lower ventral scale count (189 M. lolo ): 183–209 in M. colubrinus , 205–224 in M. ocellatus , and 197–232 in M. meridionalis . A general difference between M. lolo ̗ new species, and most other Madagascarophis is the dorsal scale count at midbody. Madagascarophis lolo ̗ new species, has 25 dorsal scale rows as does M. fuchsi , in contrast to the 27–29 typically found in M. colubrinus (rarely 25, and not syntopically), 29–33 in M. meridionalis , and 29–31 in M. ocellatus ( Glaw and Vences, 2007; Glaw et al., 2013a). It also differs genetically from all other species in the genus, e.g., M. lolo vs.

M. fuchsi , COI uncorrected pairwise distance =9.6% ( Table 1 ). For specimens not examined here ( Appendix 1 ), additional data were used from Domergue (1987) and Glaw et al. (2013a) for the diagnosis.

Description.— Adult male in excellent state of preservation, tail complete, short ventral slit midbody for DNA tissue sample, lower body slit for assessing gonad development (fully formed mature testes; 10 mm length, 2 mm width). Snout–vent length 426 mm, tail length 65 mm, tail short (13% of total body length). Head length 20 mm, width 12 mm. Head distinct from neck. Eyes large, 3 mm horizontal diameter, pupil vertically elliptical. Supralabials 8, not in contact with the eye. Infralabials 10, first pair in contact behind mental, infralabials 1–5 in contact with inframaxillaries. Rostral broader than high, 3 mm wide/1.5 mm high, visible from above. Nasal divided below nostril, in contact with 1st and 2nd supralabials. Single loreal, in contact with nasal, preoculars, prefrontal, and supralabials 2 and 3. Circumoculars 9, 1 supraocular, 2 preoculars, 3 suboculars, and 3 postoculars. Temporals 4 + 4/4 + 5. Dorsal surface of head includes pair of internasals (width 1.7 mm/length of suture 2 mm), pair of prefrontals (width 2 mm/length of suture 2.1 mm), pair of supraoculars (width 2.8 mm/length 4.8 mm), frontal longer than wide (length 5.7 mm/anterior width 2.9 mm), pair of parietals (length of suture 4.6 mm). Two pairs of inframaxillaries (anterior inframaxillary length 4.9 mm, posterior inframaxillary length 3.1 mm), posterior inframaxillaries substantially in contact with each other excepting small gular scale at posterior end ( Fig. 5 ). Dorsal scale rows 23-25-19 at 10th ventral from anterior, midbody, and 10th ventral anterior to cloaca.

Coloration and pattern.— Dorsal ground color gray in life, alternating lighter gray blotches/squares alongside vertebral column, many vertebral row scales black in coloration, giving general appearance of black dorsal line interrupted occasionally by gray scales (Fig. 1). At roughly the posterior 1/3 of the body, dorsal scale rows 7 and 8 occasionally black, giving spotted appearance in lateral view. Overall coloration pale gray in preservation. Color of iris in life gray/silver with gold flecking (Fig. 1), opaque gray in preservation. Dorsum of head, including rostral, internasals, prefrontals, frontal, supraoculars, and parietals gray. Supralabials 4–8 with gray and white mottling, infralabials with gray and white mottling. Slightly darker diffuse brown line runs from the posterior of eye to posterior margin of mouth. Tail gray with black mottling, darker and more contrasting compared to body, with slight flush of pale orange towards tail tip. Ventral scales cream with no pattern anteriorly, small amounts of gray flecking on ventral scales beginning at the posterior 1/3 of the body, continuing and increasing in intensity onto the subcaudal scales.

Natural history.— Similar to other species of Madagascarophis , M. lolo appears to be crepuscular/nocturnal; the specimen was found active on the ground at 1930 hours on tsingy karst rocks, in an exposed area with low scrub habitat. This is very similar to what has been described for M. fuchsi ( Glaw et al., 2013a) ̗ and our own observation of the M. fuchsi sample included here, which we found outside a small cave in the karst system of the Montagne des Français massif, approximately 7 0 km away. By contrast, the other species of Madagascarophis found at Ankarana, M. colubrinus , was common in canyon forests and surrounding relict forests, as well as in anthropogenically disturbed habitat. We suspect the reason that M. lolo has gone undetected for so long at Ankarana is that the exposed tsingy plateau has been poorly surveyed at night in previous expeditions due to problems of gaining safe access to these areas. Madagascarophis lolo may be endemic to the karst habitats of Ankarana, and possibly Analamerana, which is the closest karst system to the east.

Etymology.— The species name, lolo , is taken from the Malagasy word for ghost; it is a noun in apposition to the genus name. This name refers to 1) the ghostly pale gray color of the holotype, and 2) that M. lolo has eluded discovery for so long at Ankarana, arguably one of the better surveyed sites in Madagascar.

DISCUSSION

High levels of microendemicity may be common for certain regions in Madagascar ( Brown et al., 2016), such as Ankarana, where several reptile genera have endemic representatives (e.g., Alluaudina , Brookesia , Lygodactylus ; Glaw and Vences, 2007). The new species of Madagascarophis described here is, as far as we currently know, restricted to the tsingy habitat of Ankarana. It seems unlikely that this snake has never been recorded previously, given that this particular area of Ankarana is one of the most accessible areas in the national park and a popular ecotourist destination in Madagascar. However, the trail where we collected this snake was only created in the last ten years and traverses a previously inaccessible area of exposed tsingy plateau which is otherwise difficult to access, especially at night. Because this new snake is found in a national park, and its habitat is naturally well-protected from anthropogenic degradation, we do not consider this species to be vulnerable to extinction. However more survey work is needed to establish the population size and distribution limits of this snake.

Both the morphological and genetic results indicate a close/sister taxa relationship of M. lolo with M. fuchsi ( Fig. 4 ). With just a single specimen, more individuals are needed to describe the intraspecific variation of M. lolo , which is also true for the recently described M. fuchsi , known from only four specimens. There is the possibility that these two sister taxa represent populations of the same species; however, the genetic differentiation between M. lolo and M. fuchsi (e.g., COI = 9.6%; Table 1 ) is higher than or similar to the mtDNA divergence found among many species of snakes, e.g., Lachesis ( Zamudio and Greene, 1997) , Naja ( Slowinski and Wüster, 2000) , and Pantherophis ( Burbrink et al., 2000) , and is beyond what is found within other species of Madagascarophis , including the highly variable M. colubrinus ( Table 1 ; Nagy et al., 2007). Madagascarophis lolo can also be readily identified from all other species in the genus, including M. fuchsi , based on morphology alone (see Key to the species of Madagascarophis ). Our coalescent species delimitation analyses also indicate M. lolo is a distinct species, although this is best supported under small ancestral population sizes and shallow divergences (Pp = 100%). This scenario may be the most realistic for the Madagascarophis , where populations of the range-restricted M. lolo as well as M. fuchsi are likely small.

The new species described here is unique with respect to coloration. Although species of Madagascarophis (with the exception of M. ocellatus ) have extremely variable intraspecific color patterns, we have not observed any species or individuals with the same coloration seen in the specimen of M. lolo ; it possesses a pattern that appears to be well matched to the tsingy rock habitat with varying and alternating shades of gray (Figs. 1, 2). By contrast, no other species of Madagascarophis has a predominantly gray dorsal ground coloration—they are either brown, blackish brown, orange, or yellowish brown.

Although it is beyond the scope of this study to validate the status of previously described subspecies of Madagascarophis colubrinus , we discuss them here to avoid problems with synonymy with respect to M. lolo . In the most complete examination of the genus, Domergue (1987) recognized five subspecies of M. colubrinus and an additional full species, M. citrinus (as well as M. meridionalis and M. ocellatus ). More recent work on these snakes ( Nagy et al., 2007; Glaw et al., 2013a) proposed: 1) M. meridionalis and M. ocellatus remain distinct species; 2) M. c. occidentalis is a junior synonym of M. c. colubrinus ; 3) M. c. insularis is a junior synonym of M. citrinus , but M. citrinus is a subspecies of M. colubrinus ; 4) There is some genetic structure and corresponding morphological variation indicating that M. c. septentrionalis and M. c. citrinus are distinct from the nominant M. c. colubrinus ; and 5) M. fuchsi is a distinct species that occurs sympatrically with M. colubrinus at Montagne des Français.

Importantly, in our genetic analyses and in the aforementioned studies, all of the subspecies of M. colubrinus form a separate and distinct M. colubrinus clade, which is the sister taxon to M. meridionalis . Our study, like Glaw et al. (2013a), finds M. fuchsi falling outside the M. colubrinus + M. meridionalis clade, with the addition that M. lolo is the sister taxon to M. fuchsi . Therefore, all taxa within M. colubrinus are distinct from M. lolo and M. fuchsi . One subspecies, M. c. pastoriensis̗ has not been included in any molecular phylogenetic studies (due to a lack of genetic material); however, this taxon is restricted to the Antananarivo region in central Madagascar and is characterized by having a nearly black body and yellow eyes ( Domergue, 1987), which does not correspond to M. lolo .

The other Madagascarophis taxon also found at Ankarana, M. c. septentrionalis̗ is distinct from M. lolo in that it does not typically have 25 dorsal scale rows (rather 27, or 29 from sites further north) or contact of the posterior inframaxillaries (see Glaw et al., 2013a). We included M. colubrinus (which would correspond to M. c. septentrionalis) from the collecting locality of M. lolo in our genetic analyses and demonstrate that these are not sister taxa.

This study is the first to include genetic data for M. ocellatus and all other described species of Madagascarophis in a coalescent-based species tree ( Fig. 4 ). This tree was well supported at almost all nodes (Pp ± 0.99), and importantly, it provides information on the sister taxa relationship of the two most recently described species, M. lolo and M. fuchsi . Each of these species occurs sympatrically with the widespread M. colubrinus (which is the sister taxon to the more southerly distributed M. meridionalis ), but our tree indicates that no sister species of Madagascarophis occur sympatrically. These findings are similar to other studies that suggest that recently diverged sister taxa are typically allopatric and that similarity in niche may limit sympatry (e.g., Peterson, 1999; McCormack et al., 2 0 10; Pigot and Tobias, 2 0 1 3). The possible karst specialization of M. lolo and M. fuchsi may allow it to occur in the same area with the more distantly related generalist M. colubrinus .

The exception to the generally high support values across the species tree is the placement of M. ocellatus as the sister taxon to M. colubrinus + M. meridionalis (Pp = 0.62). Unlike the more widespread M. colubrinus and M. meridionalis , M. ocellatus is poorly known and is found only in the dry regions of southwestern Madagascar. Our results suggest M. ocellatus is the sister taxon to M. colubrinus + M. meridionalis ( Fig. 4 ), though we expect future studies using larger genetic datasets may be able to provide more robust support for the phylogenetic placement of M. ocellatus .

Finally, this study demonstrates that snake species new to science are likely waiting to be discovered in Madagascar, even among commonly encountered taxa, and we expect there are still high numbers of endemic, undescribed squamates in Madagascar. As many of the currently recognized squamate species in Madagascar have very large ranges (e.g., Geckolepis maculata , Zonosaurus madagascariensis , Phelsuma lineata ; Glaw and Vences, 200 7), phylogeographic studies using modern genomic techniques in an integrative context with morphology and ecology will likely discover additional taxa. Future work in Madagascar and other tropical regions worldwide should focus not only on the discovery of obvious, morphologically differentiated species, but also consider widespread taxa with potential cryptic diversity as well.

Figures

Appendix 1. Information for genetic samples used in this study; both field numbers and associated museum numbers are included when available (tissue sample only / not yet vouchered individuals have only field numbers). Institutional abbreviations follow Sabaj Pérez (2014), with the addition of ELO (collection of E. Courtois), RAN (collection of R. A. Nussbaum, University of Michigan), RAX (collection of C. J. Raxworthy, American Museum of Natural History), and TJP (collection of T. Papenfuss). * Collected on the 2014 Madagascar Expedition.

Fig. 4. Species tree from * BEAST showing the relationships of species of Madagascarophis with posterior probability support for each node indicated; scale bar indicates substitutions per site. Photos from top to bottom from FTB, SR, CJR, SR, SR.

Fig. 5. Ventral head view, showing the posterior infralabial scale contact of Madagascarophis lolo (A; RAX 12626), M. fuchsi (B; RAX 12424), M. colubrinus (C; RAX 10540); a scale bar is provided for each species. Photos by SR (A, C) and FTB (B).