Morphological variation in ‘Yaqui sucker, Catostomus bernardini, and Rio Grande sucker, Catostomus plebeius’ (Family Catostomidae)

Authors: Heather R. Neun

Year: 2009 (xli)

Abstract

Remote and often inaccessible areas present the opportunity for discovery of patterns of geographic variation in species and prospective new species. The ‘Yaqui Sucker, Catostomus bernardini, and the Rio Grande Sucker, Catostomus plebeius,’ occur naturally in some of the most remote areas of North America in rivers and streams of the Sierra Madre Occidental. In this investigation geographic variation was examined across river drainages in Catostomus bernardini ( 5 drainages) and Catostomus plebeius (5 drainages) from northwestern Mexico and southwestern United States for body, head, lip, and fin shape using a morphometric approach. A series of 44 truss landmark measurements were completed for 251 C. bernardini and 184 C. plebeius from throughout their ranges. All individuals were sexed to account for potential sexual dimorphism and eliminate this variance from shape variation. Shape differences and variation was examined using sheared Principle Components Analysis (PCA) for each species and sex. As demonstrated in many previous studies sheared PCA eliminates size from axes beyond the first to better estimate shape variation in and across populations. Results of these analyses will be discussed.