Londoño-Burbano Alejandro, Lefebvre Stéphanie L, Lujan Nathan K
Pontifícia Universidade Católica do Rio Grande do Sul, Laboratório de Sistemática de Vertebrados, Avenida Ipiranga 6681, P. O. Box 1429, 90619-900 Porto Alegre, RS, Brazil. Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, ON, M5S 2C6, Canada. Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M5S 3B2, Canada.; Email:
Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto, ON, M5S 2C6, Canada. Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M5S 3B2, Canada.; Email:
Zootaxa. 2014 Nov 17;3884(4):360-70. doi: 10.11646/zootaxa.3884.4.5.
Limatulichthys nasarcus n. sp. is described as a new species based on 15 specimens from the Ventuari and Caura Rivers in Southern Venezuela. The new species can be distinguished from its only congener, L. griseus, by the presence of anterior abdominal plates half the size of those at center of abdomen (vs. plates similar in size); distinct spots less than half of diameter of naris across entire dorsum, including snout and head (vs. indistinct dorsal spots larger or equal than diameter of naris); lateral portions of head and opercle with dark well-defined spots larger than those on dorsum (vs. spots on lateral portions of head and opercle equal in size to those on remainder of body); snout profile in dorsal view broadly rounded (vs. acutely triangular); head longer (21.4-24.2 SL vs. 17.7-21.0%); and anal fin longer (15.7-18.0 SL vs. 13.7-15.6%). Distinctiveness of the two species is further supported by their non-overlapping distribution in multivariate morphospace. The disjunct distribution of L. nasarcus across both the Caura and Ventuari rivers exclusive of the main Orinoco River channel contributes to a growing body of evidence supporting the historical connection between headwaters of these drainages. The hypothesized existence of a 'proto-Berbice' paleodrainage provides one explanation for such a connection.
基于委内瑞拉南部文图阿里河和卡乌拉河的15个标本，新物种纳氏利马突吻鱼（Limatulichthys nasarcus n. sp.）被描述。该新物种可与其唯一的同属物种灰利马突吻鱼（L. griseus）区分开来，其特征在于：腹部前板尺寸为腹部中央板的一半（相比之下，各板尺寸相似）；整个背部，包括吻部和头部，有明显的斑点，直径小于鼻孔直径的一半（相比之下，不明显的背部斑点大于或等于鼻孔直径）；头部和鳃盖的侧面有深色且界限分明的斑点，比背部的斑点大（相比之下，头部和鳃盖侧面的斑点与身体其他部位的斑点大小相等）；背视时吻部轮廓宽圆（相比之下，呈尖锐三角形）；头部更长（占标准体长的21.4 - 24.2%，相比之下为17.7 - 21.0%）；臀鳍更长（占标准体长的15.7 - 18.0%，相比之下为13.7 - 15.6%）。这两个物种的独特性在多变量形态空间中不重叠的分布进一步得到支持。纳氏利马突吻鱼在卡乌拉河和文图阿里河的分布间断，不包括奥里诺科河主河道，这一现象为支持这些排水系统源头之间的历史联系提供了越来越多的证据。关于“原始伯比斯河”古排水系统的假设存在为这种联系提供了一种解释。
