Evolution, systematics, and variation of Pacific mangrove monitor lizards (Reptilia: Squamata: Varanidae).
The complex of Pacific lizards (Squamata: Anguimorpha: Varanidae)
colloquially known as mangrove monitors is reviewed from a morphological
perspective to clarify intraspecific variation and interspecific evolution and
relationships. The study used a total of 350 museum specimens and 120 live
animals, to construct a data matrix for a preliminary set of 77 characters (later
reduced to 27). From these, a set of 12 meristic characters were subjected to
statistical analysis (principal coordinates and multidimensional scaling), while 27
binary and multistate characters were run using the phylogenetics programme
Hennig86 in a novel test of intraspecific and interspecies-group relationships.
Individuals, rather than "species", were used as terminal taxa to see how
individual-based analysis compares with contemporary species allocations.
Morphological data were used to distinguish species from a clade of at least
five sister taxa, Varanus doreanus Meyer 1874, Varanus jobiensis Ahl 1932,
Varanus spinulosus Mertens 1941, and Varanus finschi Bohme, Hom and Ziegler
1994, plus Varanus indicus*. The apparently well-defined V. indicus (Daudin,
1802) is shown to be composed of widely morphologically divergent individuals
that do not clearly segregate into geographical populations. Furthermore, some of
these individuals emerge as more closely related to other mangrove monitor
species than to members of their "own species". For these reasons, V. indicus is
here recognised as a metaspecies (V. indicus*).
Further resolution may be possible by analysis of internal anatomy or
molecular evolution (e.g., to reveal the presence of cryptic species), although the
probable recency of cladogenetic events would make such analyses of limited use.