The 4 defining characters of Argia apicalis; (A) a pearlaceous blue pterothorax and a hairline humeral stripe; (B) a thin dorsal stripe
; (C) males have a distinctive pointed and tooth-like cercus; (D) and their distribution east of the Rocky Mountains (shaded areas on map are the recorded distribution of A.
This patterning leads to chromatic components such as the dorsal stripe
, arm spots, and the iridophore splotches located on the mantle, fin, and head.
Although reference guides have indicated that "specimens lacking the red dorsal stripe
have been found in Missouri" (Johnson, 2000), and anecdotal comments suggest that they may be common in some areas of southern Missouri, we found only two P.
* Red dun--A form of dun with body color yellowish or beige; mane, tail, and dorsal stripe
When comparing the sides of the dorsum (at mid-body, excluding the dorsal stripe
), live snakes ranged from 3.5-12.8% and models ranged from 7.0-11.1%.
Dark dorsal stripe
was a darkened stripe along the center of the dorsal mantle.
Head with two wavy bright yellow stripes; dorsal stripe
running from near midorbit to posterior margin of opercle, ventral stripe extending from below anterior part of orbit (from near anterior end of snout in paratype) to base of pectoral fin; short yellow band on upper jaw near its anterior end.
When squids are calm they are usually in the Clear body pattern or Clear with Dorsal stripe
. These are cases in which a single chromatic component acts as a body pattern.