Nerodia rhombifer rhombifer
Northern Diamond-backed Watersnake

Aquatic. Net-like pattern. Belly with dark half-circles. Species account on iNaturalist

Arkansas Herpetological Atlas 2019

This species is represented by 963 records from 30 sources: 831 museum (), 0 literature (), 0 research (), and 103 observation (), with 29 additional Trauth et al. (2004) locality points remaining unsourced (). It has been museum vouchered for 56 of 75 counties (), with 6 additional counties having other forms of reported occurrence (). Years of collection range from 1897 to present.

This species occurs throughout the South Central Plains, Mississippi Alluvial Plain, and Arkansas Valley. Historical records from northwest Arkansas (UAFMC 0068-0735-0669 from 1953, LSUS 1528-1534 from 1971, and two Trauth et al., 2004 localities that remain unsourced) are questionable given recent surveys have failed to confirm its presence from this region (K. G. Roberts, pers. obs., and J. D. Willson, pers. comm.). However, records dated prior to 1966 in McDonald County, Missouri (Daniel and Edmond, 2020) and 2016 in southeastern Delaware County, Oklahoma (Sievert and Taggart, 2020) may offer some credence. Ascension up the White River valley in northcentral Arkansas is suggested by records from Bull Shoals Lake, Marion County (MPM 20332 from 1975), and northern Stone County (APSU 17898 from 1968), but additional confirmation is warranted.