|Gulf crayfish snake (Regina r. sinicola or Liodytes r. sinicola)|
This species is found on the coastal plains of both the Atlantic Coast and the Gulf Coast: in eastern Texas, southeastern Oklahoma, southern Arkansas, Louisiana, southern Mississippi, southern Alabama, northern Florida, southern Georgia, eastern South Carolina, and southeastern North Carolina. There is also a disjunct population in eastern Virginia.
Regina rigida is olive brown dorsally. Additionally, two blackish dorsal stripes may or may not be present. The upper lips (labial scales) are yellow. Ventrally it is yellow with two parallel series of black spots, which merge anteriorly into a single series. The ventral surface of the tail may have a median black line, or it may be unmarked.
The dorsal scales are arranged in 19 rows at midbody. They are strongly keeled, except for the first two rows. The first row (adjacent to the ventrals) is smooth, and the second row is weakly keeled. Ventrals 132-142; anal plate divided; subcaudals 51-71, divided.
- Regina rigida deltae (Delta crayfish snake)
- Regina rigida rigida (glossy crayfish snake)
- Regina rigida sinicola (Gulf crayfish snake)
- Liodytes rigida at the Reptarium.cz Reptile Database. Accessed 28 July 2017.
- Conant, Roger. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Second Edition. Houghton Mifflin. Boston. 429 pp. (GLOSSY WATER SNAKE Natrix rigida, pp. 150-151, Plate 21, Map 108.)
- Schmidt, K.P. and D.D. Davis. 1941. Field Book of Snakes of the United States and Canada. G.P. Putnam's Sons. New York. 365 pp. (STRIPED WATER SNAKE.—Natrix rigida Say, pp. 213-214, Figure 69.)
- Smith, H.M. and E.D. Brodie, Jr. 1982. Reptiles of North America: A Guide to Field Identification. Golden Press. New York. 240 pp. (GLOSSY CRAYFISH SNAKE Regina rigida, pp. 158-159.)
- Boulenger, G.A. 1893. Catalogue of the Snakes in the British Museum (Natural History). Volume I., Containing the Families...Colubridæ Aglyphæ... Trustees of the British Museum (Natural History). London. xiii + 448 pp. + 28 Plates. (Tropidonotus rigidus, p. 240)
- Say, T. 1825. Descriptions of three new species of COLUBER, inhabiting the United States. Journ. Acad. Nat. Sci. Philadelphia 4 (2): 237-241. (Coluber rigidus, pp. 239–240.)