The shovelnose sturgeon currently ranges throughout much of the Mississippi drainage, including the Red River in Texas. A disjunct population once existed in the Rio Grande River of Texas and New Mexico. This is known primarily from archeological material and historic accounts, but the specimen record is limited for this population.
Nearly a century and a half ago, Dr. Oscar Loew collected fish on the Rio Grande, helping to establish what would become an important historic record of the river’s fish fauna. In Albuquerque, New Mexico, he and his team collected the first and last known specimens of shovelnose sturgeon from the Rio Grande. Thanks to Dr. Loew depositing those specimens at the Smithsonian, where they persist to this day, there is firm verifiable evidence of this species occurring in the Rio Grande. Details of Lowe’s collection, published by E.D. Cope and H.C. Yarrow, are below:
Two specimens (L 51), obtained from the Rio Grande, near Albuquerque, by Dr. Oscar Loew, differ in minor and only individual characteristics from typical specimens from the Ohio River. The range of this sturgeon is thus extended farther west than has heretofore been observed. It is not included in the enumeration of fishes of the Rio Grande in Girard's Ichthyology of the United States and Mexican Boundary.
The Smithsonian Museum’s catalog ledger incorrectly attributed the specimens (USNM 15994) to Terrell Co., Texas with little other data (no collector and imprecise date). Lacking data, the specimen was of little scientific use and its Rio Grande locality was also dubious. Although others have deduced this error, The Fishes of Texas Project, stationed at the Biodiversity Center’s Collections, recently helped to correct this long-held error by connecting the specimen to the original publication, allowing staff at the Smithsonian to adjust their data. Provided here for the first time are the images of this species from the Rio Grande, courtesy of United States National Museum. Photos include ventral, lateral and an x-ray image of one of the two specimens.
The most recent report of a sturgeon from the Rio Grande was in 1991, seen just upstream of Panther Rapids. The observation, described in an unpublished manuscript by an ichthyologist familiar with the fishes of the Rio Grande, is unverifiable since a specimen or photographic evidence is lacking. According to the report, based on a clear ventral view of the head, they estimated the total length to be between 1.5 and 2 meters. That is longer than the largest known shovelnose sturgeon and the author suggests either pallid sturgeon or Gulf sturgeon may be present in the Rio Grande as well.
