Is Bocourt’s Terrific Skink Really So Terrific? Trophic Myth and Reality

Abstract

Many scientists argue that our planet is undergoing a mass extinction event that is largely due to human influences. In this context, rediscoveries of species presumed to be extinct are encouraging and of great potential interest. During a 2003 expedition to New Caledonia, Bocourt’s terrific skink, Phoboscincus bocourti, was unexpectedly rediscovered on a small islet by one of us. This skink species had been described from a single specimen collected around 1872 in New Caledonia. Since that time, however, no data on the species’ biology, trophic interactions, or role in the ecosystem have been collected, making it difficult to follow the established conservation plan. In this study, we used a multidisciplinary approach involving natural history, anatomy, morphology, genetics, and stable isotopes to elucidate the ecology of Bocourt’s terrific skink. Over the course of three different expeditions to the islet (total of 55 days across 2005 and 2012), we captured 4 individuals and observed another 4 individuals. The species’ dentition and trophic ecology suggest that it is a top predator in its ecosystem and a major consumer of small terrestrial reptiles. Its high degree of genetic relatedness to another New Caledonian skink, which has a broad distribution, suggests that P. bocourti underwent genetic isolation at a geographical remote location, where dispersal or colonization was highly improbable. Moreover, the lack of genetic variation among the four individuals we captured may imply that a unique lineage, characterized by few inter-island exchanges, exists on the islet. Bocourt’s terrific skink may be the largest terrestrial squamate predator alive in New Caledonia today. As a result, it is likely vulnerable to habitat modifications and especially the invasive rodents found on this islet. Further information is necessary to assess the conservation plans and practices in place as no concrete changes have been made since the species’ rediscovery almost 10 years ago.

Taxonomic resolution to the problem of polyphyly in the New Caledonian scincid lizard genus Lioscincus (Squamata: Scincidae)

“…Genetic analyses presented subsequently by Chapple et al (2009), Caut et al (2013) and Ineich et al (2014), while either involving less thorough sampling of New Caledonian genera, or fewer genes, have similarly found no evidence for monophyly of any combination of these four Lioscincus groups.…”

“…In contrast, Chapple et al (2009), using five mitochondrial genes and one nuclear gene, but with just four New Caledonian genera represented, found tillieri to nest deeply among the other New Caledonian genera, as sister to Caledoniscincus. Caut et al (2013), using two mitochondrial genes, neither used by Smith et al (2007), similarly found tillieri to nest among the New Caledonian genera, but as sister to Phoboscincus + nigrofasciolatus, with Caledoniscincus outside this (Caut et al, 2013). "Lioscincus" nigrofasciolatus was recovered as sister to Phoboscincus by Caut et al (2013), but with low support, and Lioscincus steindachneri has consistently been recovered as sister to Celatiscincus (Ineich et al, 2014).…”

“…A later genetic study concentrating on the endemic New Zealand skink fauna (Chapple et al, 2009), but using a larger number of genes, confirmed the endemic New Caledonian and New Zealand skink genera as a monophyletic lineage with the New Caledonian and New Zealand skink fauna as discreet sister lineages, and also the polyphyly of Lioscincus. Further contributions highlighting the polyphyly of Lioscincus were apparent in the molecular phylogenies of Caut et al (2013) and Ineich et al (2014) in investigating the relationships of the giant New Caledonian skink Phoboscincus bocourti (Brocchi). It is the purpose of this paper to diagnose the evolutionary lineages currently included under Lioscincus and to erect new genera for those taxa no longer included in that genus.…”

The identity of twelve scincid generic names proposed by Cope in 1892 (Squamata: Scincidae)

“…Monophorus is a senior subjective synonym of Phoboscincus Greer 1974. Phoboscincus has been used as the name for a genus consisting of bocourtii and garnieri by the following 25 papers by more than 10 authors in the past 50 years, and over a period of not less than 10 years: Sadlier (1987); Bauer & vindum (1990); Bauer & Sadlier (1993, 2000; Adler et al (1995); Sadlier & Bauer (1997a,b); Greer (2001); Ineich (2006Ineich ( , 2009; Greer & Chong (2007); Smith et al (2007); Meiri (2008); Mittermeier et al (2009); Beolens et al (2011);Caut et al (2013); Geneva et al (2013); Hedges (2014); Ineich et al (2014); Daza et al (2015); Langner & Sound (2016); Thibault et al (2017); Sadlier et al (2019); Rodda (2020); O 'Shea (2021).…”

X-ray microtomography provides first data about the feeding behaviour of an endangered lizard, the Montserrat galliwasp ( Diploglossus montisserrati )

“…With dead specimens, a dissection can be performed to observe the stomach contents of fresh or alcohol-preserved specimens [5]. Finally, isotopic analysis [6] and inferences based on dental morphology [7] can be done on living, dead and fossil specimens. However, which is the method to apply in the case of unique or rare museum specimens?…”