Branch William R, Bayliss Julian, Bittencourt-Silva Gabriela B, Conradie Werner, Engelbrecht Hanlie M, Loader Simon P, Menegon Michele, Nanvonamuquitxo Cristóvão, Tolley Krystal A
Herpetology Department, Port Elizabeth Museum (Bayworld), P.O. Box 13147, Humewood, Port Elizabeth, 6013, South Africa Department of Zoology, Nelson Mandela University, Port Elizabeth, 6013, South Africa.
Zootaxa. 2019 Jul 25;4646(3):zootaxa.4646.3.6. doi: 10.11646/zootaxa.4646.3.6.
A new species of tree snake Dipsadoboa montisilva Branch, Conradie Tolley sp. nov. (Serpentes: Colubridae) is described from the 'sky islands' of Mount Mabu and Mount Ribáuè in northern Mozambique. Features of scalation, colour, body form and habitat distinguish the new species from other Dipsadoboa. This is supported by a phylogenetic analysis using one mitochondrial marker (cytochrome b) that shows the new Mozambican species is divergent from other sampled Dipsadoboa, including D. flavida and D. aulica, the only congeners known to occur in Mozambique. Morphologically, the new Dipsadoboa forms part of the D. werneri-shrevei complex from east and southeast Africa, but differs in having higher subcaudal counts, a different temporal pattern and only two supralabials entering the orbit. Phylogenetically, it occurs in a clade with D. shrevei and D. werneri. The status of D. shrevei in East Africa is reassessed, particularly in terms of the poorly-known Dipsadoboa shrevei kageleri from northern Tanzania. It is morphologically well defined from D. shrevei shrevei and utilises a different habitat. Although based on limited genetic data, it appears to be well-defined from typical D. shrevei and is accordingly raised to specific status. The only Tanzanian record for typical D. shrevei from Mtene, Rondo Plateau in southeast Tanzania is well isolated from the species' range to the west (e.g. Zambia, Angola) and the published scalation features, particularly ventral counts, do not fully accord with D. shrevei. The Rondo Plateau population is treated as Dipsadoboa incerta sedis, and because we return D. shrevei to its binomial status, we can no longer consider D. shrevei as occurring in Tanzania. Biogeographically, the Rondo Plateau population may have a stronger affinity to the new Mozambican species. The discovery of isolated populations of the new species in mid-altitude forest remnants on Mt Mabu and Mt Ribáuè emphasizes the high conservation importance of the Mozambique forest 'sky islands' from which numerous other endemic new species have been recently discovered. These species are impacted by ongoing habitat destruction through slash and burn clearing for subsistence agriculture.
一种新的树蛇——蒙蒂西尔瓦迪普萨多博阿蛇（Dipsadoboa montisilva Branch, Conradie & Tolley sp. nov.）（蛇目：游蛇科），是从莫桑比克北部的马布山和里鲍埃山的“天空之岛”发现并描述的。其鳞片特征、颜色、体型和栖息地使其与其他迪普萨多博阿蛇区分开来。使用一个线粒体标记（细胞色素b）进行的系统发育分析支持了这一点，该分析表明这种新的莫桑比克蛇与其他采样的迪普萨多博阿蛇不同，包括莫桑比克已知仅有的同属物种黄迪普萨多博阿蛇（D. flavida）和奥氏迪普萨多博阿蛇（D. aulica）。从形态学上看，这种新的迪普萨多博阿蛇是东非和东南非的韦氏迪普萨多博阿蛇 - 施氏迪普萨多博阿蛇复合体的一部分，但不同之处在于它的尾下鳞数量更多、颞部图案不同且只有两枚上唇鳞进入眼眶。在系统发育上，它与施氏迪普萨多博阿蛇（D. shrevei）和韦氏迪普萨多博阿蛇（D. werneri）同属一个分支。对东非施氏迪普萨多博阿蛇的地位进行了重新评估，特别是对于来自坦桑尼亚北部鲜为人知的卡格勒氏施氏迪普萨多博阿蛇（Dipsadoboa shrevei kageleri）。它在形态上与施氏迪普萨多博阿蛇指名亚种（D. shrevei shrevei）有明显区别，且利用不同的栖息地。尽管基于有限的遗传数据，但它似乎与典型的施氏迪普萨多博阿蛇有明显区别，因此被提升为独立物种。来自坦桑尼亚东南部隆多高原姆泰内的典型施氏迪普萨多博阿蛇的唯一记录与该物种在西部的分布范围（如赞比亚、安哥拉）相距甚远，并且已公布的鳞片特征，特别是腹鳞数量，与施氏迪普萨多博阿蛇并不完全相符。隆多高原的种群被视为分类地位不确定的物种，并且由于我们恢复了施氏迪普萨多博阿蛇的双名法地位，我们不再认为施氏迪普萨多博阿蛇在坦桑尼亚存在。在生物地理学上，隆多高原的种群可能与新的莫桑比克物种有更强的亲缘关系。在马布山和里鲍埃山的中海拔森林残余地发现新物种的孤立种群，强调了莫桑比克森林“天空之岛”的高度保护重要性，最近在那里还发现了许多其他地方性新物种。这些物种正受到为维持生计而进行的刀耕火种式开垦导致的持续栖息地破坏的影响。
