Sexual Dimorphism in Occurrence of Keeled Dorsal Scales in the Eastern Indigo Snake (Drymarchon corais couperi)

Effects of body size and sex of Drymarchon couperi (eastern indigo snake) on habitat use, movements, and home range size in Georgia

“…Therefore, we would predict that sex influences home range size in indigo snakes, with males occupying larger ranges than females because of behavioral differences. Alternatively, home range size may not be directly affected by sex, but a sexually dimorphic pattern may emerge because males, on average, are larger (male-biased sexual size dimorphism; Layne and Steiner 1984;Stevenson et al 2003Stevenson et al , 2009, and therefore have potentially greater resource needs that influence home range size (Harsted andBunnell 1979, Tufto et al 1996). Patterns and scale of movement and habitat use within a landscape may be correlated with arrangement of necessary resources (Gibbons and Semlitsch 1987, Gregory et al 1987, Macartney et al 1988.…”

Variability and significance of parietal and ventral scales in the marine snakes of the genus Lapemis (Serpentes, Hydrophiidae), with comments on the occurance of spiny scales in the genus / Paul Gritis, Harold K. Voris.

“…Generally these spines are considered to be nonseasonal in occurrence, although seasonality has been suggested for Tretanorhinus nigroluteus lateralis (Henderson & Hoevers, 1 979), and for Drymarchon (Layne & Steiner, 1984). Although empirical data are lacking, we consider it likely that the spines in Lapemis play a role in courtship (stimulation) or copulation (enhancing body contact).…”

“…"Knobbed anal keels" on the dorsal scales of the anal region have been observed in Natrix (= Nerodia), Thamnophis, Diadophis, Carphophis, and Farancia (Blanchard, 1931); in Aspidura trachyprocta (Davis, 1936, p. 273); in Tropidoclonion lineatum (Force, 1936); and in Tretanorhinus (Henderson & Hoevers, 1979). Low keels on dorsal scales have been recorded from adult male Drymarchon corais couperi (Layne & Steiner, 1984).…”

Systematics of the Neotropical SnakeDendrophidion paucicarinatum(COPE), with a Description of its Hemipenis (Serpentes: Colubridae)

“…A suggested sexual difference in the degree of keeling on the dorsal scales mentioned above needs further quantification. Sexual dimorphism in the degree of keeling on dorsal scales in snakes has been reported infrequently, but does occur in some species (for a brief discussion see Layne and Steiner, 1984).…”