steinitzi 1 3 2 20 17 3 * One specimen with 24 caudal vertebrae
first vertebrae (FV); abdominal vertebrae groups one to three (AV1, AV2, AV3); caudal vertebrae
groups one and two (CV1, CV2); penultimate vertebrae (PUV); and ultimate vertebrae (UV).
Abdominal/caudal vertebral configuration Type A, with haemal arches of first two caudal vertebrae
expanded to accommodate posterior extension of swimbladder (Fig.
Dorsal zygapophyses prominent on anterior vertebrae, ventral zygapophyses present on posterior precaudal and caudal vertebrae
where D1=the first discriminant score of an individual; od=orbit depth divided by HL; iou)=interorbital width divided by HL; pfi=pectoral-fin base depth divided by HL; pZ=pectoral fin length divided by HL; cpuZ=caudal peduncle ventral length divided by HL; p<iZ=predorsal length divided by HL; ppZ=prepectoral length divided by HL; gr=the number of gill rakers on the entire gill arch; llp=ihe number of lateral-line pores; dp=the number of dermal plicae; ap=the number of anal-fin pterygiophores anterior to the first haemal spine; pco=the number of precaudal vertebrae; and cu=the number of caudal vertebrae
Rivulus was considered to be a monophyletic group based on the morphology of the shoulder girdle and the neural prezygapophyses of caudal vertebrae
In living sea snakes, which have strongly compressed paddle-like tails, the caudal vertebrae
are modified in their morphology (usually by strong lateral compression and often tall, narrow neural spines and/or compressed ventrolateral processes that project ventrally rather than laterally) and articulation (strongly overlapping neural arches to give rigidity to the tail region).
In the first tetrapods, there was specialization of the anterior cervical vertebrae into a primitive atlas-axis complex, as well as a distinct split into a cervical trunk, sacral and caudal vertebrae
, and interlocking vertebral centra with upright neural arches.