This is the primary feature used to separate species and subspecies in this genus. The color pattern consists of three black or deep brown stripes on the dorsal part of the head, one mid-dorsally, and one on each side of the head passing through the eye. On the body, there are usually dark longitudinal stripes on a pale tan or white background. There may be as few as three in vittatus, and as many as 13 in l. dunni; except that there is none in C. l. concolor. There are two pairs of primary dark stripes. The first is the body stripe that is the posterior extension of the stripe which on the head passes through the eye and is termed the lateral stripe. The other primary stripe is the posterior continuation of the mid-dorsal head stripe. Usually it is split into two dorsolateral stripes on the body. Stripes may be present on the scale-row to either side of the primary stripe. These stripes are usually dark brown or black and are the secondary stripes. Finally, additional stripes may be present that are paler brown and bear no direct relationship to the primary stripes. These are auxiliary stripes.
Every stripe originates either as broad continuous stripe or as a row of spots or dashes, forming a discontinuous stripe, which in some specimens becomes continuous posteriorly. The stripes are usually black or deep brown, although auxiliary stripes are sometimes paler. The dorsal ground color is pale brown, tan, olive, or white; usually the ground color is palest ventrally and darkest dorsally.
In some specimens of Conophis the lateral tips of the ventrals are spotted, one spot on each end of each ventral. Otherwise, the ventrals are immaculate white.
In some species there is considerable ontogenetic change in color pattern, although the juveniles bear the basic color characteristics of the adults. For example, juveniles of the sympatric species C. lineatus dunni and C. pulcher can be separated on the basis of which scale-rows are darkly pigmented. C. l. dunni has eight stripes in juveniles and as many as 13 in adults. Juveniles show a greater contrast between the black stripes and the pale ground color than do adults. With increased age (size) the stripes in some populations become paler and are split; simultaneously the ground color becomes darker.
Sexual dimorphism is evident in all species and subspecies of Conophis. Differences always exist in the number of subcaudals and in the tail/body ratio; males have more subcaudals and relatively longer tails than do females (table 3). Otherwise, there is little sexual dimorphism in these snakes. Males and females cannot be differentiated by any feature of coloration.
Formulation of a biological concept of the species as defined by Mayr (1942) is difficult when most of the data primarily relied upon are from preserved specimens. Nevertheless, a total view of variation was attempted so that differences within and between populations could be recognized. Differences, between populations, that seem to be part of a continuous or internal cline (Huxley, 1942) are not used for characterizing subspecies.
Fig. 1. Patterns of dorsal coloration at mid-body of adults of all species and subspecies of the genus Conophis except C. lineatus concolor. A. C. lineatus dunni (UMMZ 107339) from Santa Rosa, Guatemala. B. C. lineatus dunni (UMMZ 116537) from 1.5 mi. N Matagalpa, Nicaragua. C. C. lineatus dunni (ANSP 3480) from "San Jose," Costa Rica. D. C. l. lineatus (KU 23253) from Río Blanco, 20 km. WNW Piedras Negras, Veracruz, México. E. C. nevermanni (ANSP 22424) "San Jose," Costa Rica. F. C. pulcher (UIMNH 33646) from Soconusco, Chiapas, México. G. C. vittatus (KU 39626) from Atencingo, Puebla, México. H. C. vittatus (TCWC 9473) from 1 mi. S Colotlipa, Guerrero, México. I. C. vittatus (UMMZ 82653) from "vicinity of" Salina Cruz, Oaxaca, México. Approximately × 3/4.