Phylogenomics, biogeography and taxonomic revision of New Guinean pythons (Pythonidae, Leiopython) harvested for international trade

The large and enigmatic New Guinean pythons in the genus Leiopython are harvested from the wild to supply the international trade in pets. Six species are currently recognized (albertisii, biakensis, fredparkeri, huonensis, meridionalis, montanus) but the taxonomy of this group has been controversial. We combined analysis of 421 nuclear loci and complete mitochondrial genomes with morphological data to construct a detailed phylogeny of this group, understand their biogeographic patterns and establish the systematic diversity of this genus. Our molecular genetic data support two major clades, corresponding to L. albertisii and L. meridionalis, but offer no support for the other four species. Our morphological data also only support two species. We therefore recognize L. albertisii and L. meridionalis as valid species and place L. biakensis, L. fredparkeri, L. huonensis and L. montanus into synonymy. We found that L. albertisiiand L. meridionalis are sympatric in western New Guinea; an atypical pattern compared to other Papuan species complexes in which the distributions of sister taxa are partitioned to the north and south of the island’s central mountain range. For the purpose of conservation management, overestimation of species diversity within Leiopython has resulted in the unnecessary allocation of resources that could have been expended elsewhere. We strongly caution against revising the taxonomy of geographically widespread species groups when little or no molecular genetic data and only small morphological samples are available.

分类学上隶属于Leiopython（光盾蟒属）的体型庞大且极具神秘色彩的新几内亚蟒蛇，常被从野外捕获以供应国际宠物贸易。目前该类群公认包含6个物种（albertisii、biakensis、fredparkeri、huonensis、meridionalis、montanus），但该类群的分类学地位长期存在争议。本研究结合421个核基因座（nuclear loci）与完整线粒体基因组（mitochondrial genomes）的分析结果，以及形态学数据，构建了该类群的详细系统发育（phylogeny）关系，以解析其生物地理格局并明确该属的系统分类多样性。本研究的分子遗传学数据支持该类群存在两大演化支（clades），分别对应L. albertisii与L. meridionalis，但并未为其余四个物种提供分类学支撑；形态学数据同样仅支持两个有效物种。因此本研究认定L. albertisii与L. meridionalis为有效物种，将L. biakensis、L. fredparkeri、L. huonensis及L. montanus归为同物异名。本研究发现L. albertisii与L. meridionalis在新几内亚西部存在同域分布（sympatric）；这一分布模式与其他巴布亚物种复合体（species complexes）的典型模式截然不同——后者的姊妹类群（sister taxa）分布分别局限于该岛中央山脉的南北两侧。从物种保护管理的角度来看，对Leiopython属物种多样性的高估，导致了本可投入其他保护领域的资源被不必要地占用。本研究强烈警示：在仅拥有少量甚至完全缺乏分子遗传学数据、且形态学样本量不足的情况下，不应随意修订地理分布广泛的物种类群的分类学地位。