The sepals of the calyx dorsally bear blunt, thickened, longitudinal keels where 'circum-floral nectaries' (CFNs) are located.
Many major osteoderms have distinct longitudinal keels at the midheight or higher, with a laterally or dorsolaterally-directed axis (Fig. 2).
Most of the dorsal plates have a longitudinal ridge, or keel.
Snake scales may be granular, have a smooth surface or have a longitudinal ridge or keel on it.
0. The dorsal head surface longitudinal bulge or keel: (0) present; (1) absent.
Pareuryomma can be distinguished from Notocupes by the following characters: dorsal head surface without longitudinal bulge or keel; antennae moniliform, antennomeres 7 11 widened distally; pronotum widest anteriorly, narrowing posteriorly; abdominal ventrites arranged in one plane, not overlapping.
A distinct and sharp longitudinal bulge or keel is present on the dorsal side of the head of Notocupoides, Notocupes, Rhabdocupes, Zygadenia, Eurydictyon and Amblomma[ 33], and also in Permocupes and Platycupes[ 3]. 1. Posteromesal dorsal protuberance of the head[ 12] : (0) present; (1) absent.
This clade is supported by the absence of a longitudinal bulge or keel on the dorsal head surface (ch. 0 1), the distinct elongation of the third antennomere (ch. 11 1), and the small size of the window punctures on the elytron (ch. 25:1).
In fact, Pareuryomma differs from the Notocupes (Zygadenia) in several characters: the absence of protuberances or longitudinal bulges or keels on the dorsal surface of the head, moniliform antennae, a quadrate pedicellum, a wide epipleural rim, and the abutting arrangement of the abdominal sterna.
