Section of Ecology and Systematics, Division of Biological Sciences, Cornell University, Ithaca, N.Y. 14853–2701, USA.
Systematics of myliobatoid elasmobranchs: with emphasis on the phylogeny and historical biogeography of neotropical freshwater stingrays (Potamotrygonidae: Rajiformes)
Article first published online: 28 JUN 2008
Zoological Journal of the Linnean Society
Volume 117, Issue 3, pages 207–257, July 1996
How to Cite
LOVEJOY, N. R. (1996), Systematics of myliobatoid elasmobranchs: with emphasis on the phylogeny and historical biogeography of neotropical freshwater stingrays (Potamotrygonidae: Rajiformes). Zoological Journal of the Linnean Society, 117: 207–257. doi: 10.1111/j.1096-3642.1996.tb02189.x
- Issue published online: 28 JUN 2008
- Article first published online: 28 JUN 2008
- Received November 1994, accepted for publication July 1995
- South America Amazon;
The neotropical freshwater family Potamotrygonidae appears to be the only stingray group that has radiated in a non-marine environment. To assess the affinities of potamotrygonids to other rays, a phylogenetic analysis was undertaken using 39 morphological characters from 18 stingray groups. The single tree produced (CI = 0.80, RI = 0.88) suggests that neotropical freshwater rays are a monophyletic group, and that within Potamotrygonidae, Paratrygon is basal to a clade composed of Plesiotrygon and Potamotrygon. The sister group to potamotrygonids was determined to be amphi-American Himantura—these taxa share synapomorphies of the ventral mandibular musculature and the hyomandibular/mandibular articulation. The topology suggests that potamotrygonids are derived from a freshwater-invading ancestor that was distributed along the northern coast of South America (Pacific and Caribbean) prior to the emergence of the isthmus of Panama. This hypothesis conflicts with parasite-based biogeographic scenarios of a stricdy Pacific origin for potamotrygonids. General systematic results concerning urolophids, dasyatids, and pelagic myliobatoid stingrays are also discussed.