A new salamander from the late Paleocene-early Eocene of Ukraine
A new salamander from the late Paleocene-early Eocene of Ukraine
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DOI：
10.4202/app.2010.0101
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发表时间：
2012-03-01
影响因子：
1.8
通讯作者：
Gubin, Yuri M.
中科院分区：
文献类型：
--
作者：
Skutschas, Pavel P.;Gubin, Yuri M.
根据乌克兰中部切尔卡西地区岩心板上保存的14具古新世晚期至始新世早期的化石，描述了一种新的新第三纪蝾螈——semobatrachus boltyschkensis gen. et sp. nov.。该新分类群具有以下独特的特征组合：前颌背突向后拉长并与额部重叠；上颌骨大大缩小；无顶叶鳞片接触；下颌齿排长且与上颌拱廊平行；翼状骨前突长；方形的僵化;边缘和腭齿有花梗；主干椎骨两突状，各有中央下龙骨、前基底突和脊神经孔；肋骨有两头的;腕骨和跗骨未石化；指骨方为2-2-3-2，指骨方为2-2-3-2，指骨方为2-2-3-2。系统发育分析表明S. boltyschkensis在Urodela（即冠支蝾螈）中有巢穴，但其确切的系统发育位置不明确，有三种解决方法：(1)与Salamandra和Ambystomatidae + (Dicamptodon + Rhyacotriton)的三分形未解决(结果在NONA v. 2.0中获得，使用WINCLADA v. 1.00.08界面；(2)作为（Salamandra + (Ambystomatidae + (Dicamptodon + Rhyacotriton))）进化枝的姐妹分类群（TNT v. 1.1，隐式枚举搜索算法所得）或(3)作为Ambystomatidae的姐妹分类群（PAUP v. 4.0b10，分支定界搜索算法所得）。
A new neotenic salamander, Seminobatrachus boltyschkensis gen. et sp. nov., is described based on 14 skeletons of late Paleocene-early Eocene age preserved on drill core slabs from the Cherkassy Region, central Ukraine. The new taxon is diagnosed by the following unique combination of characters: dorsal process of premaxilla posteriorly elongate and overlaps frontal; maxilla greatly reduced in size; parietal squamosal contact absent; vomerine tooth row long and parallel to maxillary arcade; pterygoid has long anterior process; quadrate ossified; marginal and palatal teeth pedicellate; trunk vertebrae amphicoelous, each having a subcentral keel, anterior basapophysis, and spinal nerve foramina; ribs bicipital; carpals and tarsals unossified; and phalangeal formulae of 2-2-3-2 and 2-2-3-4-2 for manus and pes, respectively. Phylogenetic analysis nests S. boltyschkensis within Urodela (i.e., crown-clade salamanders), but its exact phylogenetic position is equivocal, resolving in one of three ways: (1) in an unresolved trichotomy with Salamandra and (Ambystomatidae + (Dicamptodon + Rhyacotriton)) (results obtained in NONA v. 2.0, with the WINCLADA v. 1.00.08 interface; the parsimony ratchet (island hopper) algorithm), (2) as a sister taxon of (Salamandra + (Ambystomatidae + (Dicamptodon + Rhyacotriton))) clade (results obtained in TNT v. 1.1; the implicit enumeration search algorithm) or (3) as a sister taxon of Ambystomatidae (results obtained in PAUP v. 4.0b10; the branch-and-bound search algorithm).