Journal article
Two new cis-Andean species of the South American catfish genus Megalonema allied to trans-Andean Megalonema xanthum, with description of a new subgenus (Siluriformes: Pimelodidae)
Neotropical ichthyology, v 6(3), pp 439-454
01 Jul 2008
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
A revised diagnosis of the pimelodid catfish genus Megalonema is given based on synapomorphic features of the Weberian complex and gas bladder. Megalonema xanthum from the Magdalena River is redescribed. Two new cis-Andean species of Megalonema are described, M. oniaxanthum n. sp. from the Amazon River basin, and M. orixanthum n. sp. from the Orinoco River basin. These three species are differentially diagnosed by shape and size of the supraoccipital posterior process, adipose-fin shape, vertebral Counts, eye size, premaxillary bone shape and dentition, length of the anal-fin base, width between the posterior nostrils and presence/absence of dentations on the pectoral spine. Eretmomegalonema new subgenus is established for M. xanthum, M. amaxanthum and M. orixanthum and Supported by the uniquely synapomorphic paddle-like structure of its pelvic fin and hypertrophied basipterygium. Unambiguous synapomorphies indicate a sister-group relationship between M. amaxanthum and M. orixanthum, with M. xanthum basal to this pair. This topology is congruent with the Neogene origins of separate Magdalena, Amazon and Orinoco basins Suggesting vicariant control of diversification of Eretnomegalonema.
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Details
- Title
- Two new cis-Andean species of the South American catfish genus Megalonema allied to trans-Andean Megalonema xanthum, with description of a new subgenus (Siluriformes: Pimelodidae)
- Creators
- John G. Lundberg - Drexel UniversityWasila M. Dabdul - Natl Acad Sci, Dept Ichthyol, Philadelphia, PA 19103 USA
- Publication Details
- Neotropical ichthyology, v 6(3), pp 439-454
- Publisher
- Soc Brasileira Ictiologia
- Number of pages
- 16
- Grant note
- DEB-0315963 / All Catfish Species Inventory (ACSI, US National Science Foundation); National Science Foundation (NSF) DEB-0089612 / US National Science Foundation; National Science Foundation (NSF)
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Biodiversity, Earth, and Environmental Science (BEES); Academy of Natural Sciences of Drexel University
- Web of Science ID
- WOS:000260286800018
- Scopus ID
- 2-s2.0-55549104427
- Other Identifier
- 991019335243804721
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- Web of Science research areas
- Zoology