Grismer, L. Lee

English

The University of Kansas: Journals@KU

 IRCF ReptIles & AmphIbIAns  •  Vol 16, no 4  •  DeC 2009 259new faces from ancient Places:  uncovering Peninsular Malaysia’s  Hidden lizard diversityPart II: skinksl. lee GrismerDepartment of biology, la sierra universityRiverside, California, usA (lgrismer@lasierra.edu)All photographs by the author.how many times have you walked along a shady forest trail and quickly turned to see what was rustling in the leaf litter — only to catch a glimpse of something dark and shiny, a split second before it darted behind a log or under a bush? later, down that same trail, you could swear you caught a glint of something in the sunlight just before it circled around to the backside of a tree. Well, don’t despair, it happens to all of us. If you were in peninsular malaysia, more than likely what you saw was one of the region’s 36 species of actively foraging, con-stantly moving skinks. this is really no surprise, given that the family scincidae is the most diverse group of reptiles in the world. upwards of 1,300 species are currently recognized, comprising nearly one-third of the world’s known species of lizards. Also, as you might have guessed, skinks are most diverse in the tropics. they really are quite an amazing lot as well. Although they vary remark-ably in anatomy and lifestyle, nearly all skinks have relatively long, shiny bodies and tails and, in many groups, exhibit an independent evolution of limb reduction and loss. most skinks are terrestrial and show an amazing array of anatomical and behavioral adaptations for living in restrictive microhabitats. In peninsular malaysia, the majority of skinks are forest-floor or climbing species, and a few are limbless or nearly limbless fossorial forms. All are covered with shiny scales, and each scale is underlain by a thin plate of bone called an osteoderm. this smooth, hard exterior makes skinks extremely durable and difficult to grab. In fact, many species of snakes that feed on skinks (such as the oriental Whip snake, Ahaetulla prasina) have independently evolved specialized mechanisms for grasping and holding them. penInsulAR mAlAYsIAn sKInKsthe striped pattern of Larutia seribuatensis might serve a protective function by creating a visual illusion that can confuse potential predators.260 IRCF ReptIles & AmphIbIAns  •  Vol 16, no 4  •  DeC 2009these features include hinged maxillary teeth and gaps in tooth rows in which the skink’s body is trapped. I find researching skinks to be the ultimate test of my patience. eight species in peninsular malaysia are known from three or fewer individuals. Countless are the times when I have crossed the pacific ocean to go to the places where they are supposed to occur, only to miss them. however, this is not to say I struck out. one of the great things about skinks is that they are good at partitioning environ-mental resources. Consequently, you can find a high number of spe-cies in one place. even if that place has not been visited frequently, some of those species are likely to be new to science. During my quests over the last five years to find rare species such as Sphenomorphus cameronicus in the banjaran titiwangsa or Lipinia surda in the seribuat Archipelago, my team has been for-tunate enough to discover and describe six new species of skinks, all of which are endemic to peninsular malaysia or its associated Archipelagos. one of the most interesting new skinks is a nearly limbless species of the genus Larutia. the larut skinks are named after bukit larut, the locality of the type species, Larutia larutensis. While surveying the satellite island of tulai off the coast of pulau tioman in the seribuat Archipelago, we found three specimens of a strange, snake-like skink beneath some surface debris and leaf litter. We quickly determined it to be a new member of the genus. What is most perplexing about this new species is that the five other species of Larutia, including the new species’ closest relative, L. trifasciata from the banjaran titiwangsa, are all upland fossorial cloudforest lizards from peninsular malaysia, sumatra, or borneo — whereas this new species, which was named L. seribuatensis, was found at sea level in relatively arid conditions. Additionally, it had a complete striping pattern that suggests it spends a significant amount of time above ground moving through the leaf litter. As in striped snakes, GRIsmeRunlike the newly described Larutia seribuatensis, which occurs at sea level and appears to be active on the surface, the new species’ closest relative (L. trifas-ciata, illustrated here) is an upland fossorial cloudforest denizen.some peninsular malaysian forest skinks, such as the blotched Forest skink (Sphenomorphus praesignus), are large, long-limbed, colorful, and diurnally active. IRCF ReptIles & AmphIbIAns  •  Vol 16, no 4  •  DeC 2009 261the striped pattern serves a protective function by creating a visual illusion that can serve to confuse potential predators. the five other new species of skinks that my team and I dis-covered and described are all in the genus Sphenomorphus, the forest skinks. In peninsular malaysia, forest skinks fall into two broad cate-gories. some species, such as the blotched Forest skink (S. praesignus), are large, long-limbed, colorful, and diurnal terrestrial or climbing species whose foraging and basking behaviors make them conspicuous components of the ecosystems they inhabit. others, however, such as the bukit larut Forest skink (S. butleri), are small, brownish, nonde-script, and secretive leaf-litter specialists with short limbs and elongate bodies and tails whose lifestyles leave them poorly understood and rarely seen. most of these are upland or insular endemics, and our five new species all fall within this latter group of small skinks. now, I admit that these skinks are not nearly as “cool” looking as some of our newly discovered geckos that have flaming yellow heads, electric white tails, and colorful banding patterns. however, these little skinks are equally exciting in a different way, mainly because they provide us with clues as to how evolution works. the fact that these geographically isolated species stuck on islands and mountaintops scattered all over peninsular malaysia look very simi-lar to one another makes a bold statement about how natural selec-tion operates on a common genotype shared between multiple spe-cies. In essence it says: “If you have the common genetic blueprint of Sphenomorphus and you are terrestrial, less than 50 mm in snout-vent length, and live in leaf litter, then you’ll survive best if you look and behave like this.” In fact, discerning one species from another is very difficult without a close, microscopic examination. so, for an evolutionary biologist, this is an exciting example of how evolution “edits” basic genetic material to produce a body plan and a lifestyle best suited to widely separated but similar environments.penInsulAR mAlAYsIAn sKInKsother malaysian species, such as the bukit larut Forest skink (Sphenomorphus butleri), are small, brownish, nondescript, and secretive leaf-litter specialists with short limbs and elongate bodies and tails.Sphenomorphus ishaki, the pulau tioman Forest skink, is unique in that it is known only from higher elevations and is active only during cool, cloudy days.262 IRCF ReptIles & AmphIbIAns  •  Vol 16, no 4  •  DeC 2009 Four of the five new species of Sphenomorphus are insular endemics. Sphenomorphus ishaki, the pulau tioman Forest skink, is unique in that it is known only from the upper elevations of Gunung Kajang and is abroad only during cool, cloudy days. this is a significant behavioral departure from most skinks, which are commonly active on hot, sunny days. Another, S. sibuensis, the pulau sibu Forest skink, occurs at sea level in coastal vegetation that fringes the mangrove swamps on pulau sibu. It is known from only two specimens that were collected almost exactly one year apart under the exact same small log! this may indicate some-thing about the extreme microhabitat specificity of this new spe-cies. the third insular endemic comes from pulau perhentian besar of the perhentian Archipelago. this species, S. perhentianensis, the perhentian Forest skink, is known from only a single specimen, but was sufficiently distinctive to warrant its own specific recogni-tion. It was found foraging on the forest floor immediately follow-ing a heavy afternoon rain shower. It also is the only member of this group of skinks known from northeastern malaysia. the remaining insular species comes from the langkawi Archipelago, where it is known from pulau langkawi and the smaller, adjacent pulau singa besar. Curiously, the pulau langkawi individual was found near the summit of machinchang at an elevation of >750 m, whereas the lizard from pulau singa besar, was found near sea level. Clearly this species’ degree of microhabitat specificity is not nearly as restric-tive as that of S. sibuensis. the last endemic species, Sphenomorphus bukitensis, comes from the banjaran titiwangsa. We found this spe-cies one night while turning logs at Fraser’s hill, and subsequently found it again farther north in the Cameron highlands. this spe-cies is so small and so secretive that it likely occurs over the entire length of the mountain range. We just haven’t looked hard enough yet to find it elsewhere. so, what do all these new species described during the past five years indicate? Just like the geckos you may have read about in the last issue of Reptiles & Amphibians, it means that we have a long way to go before we really know just how many different species of skinks occur in peninsular malaysia. the fact that we have discov-ered and described many more new species of geckos than species of skinks merely reflects the reality that geckos are much easier to find and don’t run nearly as fast. so, the next time you are walking along a forest trail and you hear something in the leaves and you just can’t get a good look at it, it is probably a skink. It could even be a species we have never seen, although we may have heard it any number of times!GRIsmeRthe only known example of Sphenomorphus perhentianensis, the perhentian Forest skink, was found foraging on the forest floor immediately following a heavy afternoon rain shower.Sphenomorphus bukitensis, the titiwangsa Forest skink, is so small and so secretive that it likely has a much more extensive distribution than that indicated by the few known individuals.

New Faces from Ancient Places: Uncovering Peninsular Malaysia’s Hidden Lizard Diversity Part II: Skinks

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New Faces from Ancient Places: Uncovering Peninsular Malaysia’s Hidden Lizard Diversity Part II: Skinks

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