Acta Zoologica Cracoviensia, 31() 1988
A survey of neural bone variation among recent chelonian species, with functional interpretations
Abstract:
Neural bones are by far the most variable elements of the turtle shell. The presumed ancestral condition of about eight predominantly hexagonal neurals, each of which has the broad end anteriorly directed, may be modified in many ways — by proliferation of elements (to as many as fifteen); by reduction (usually at the ends of the series), with total loss of neurals in the extreme condition; and by changing in shape, by broadening, narrowing, reduction to isolated kite-shaped elements, reversal (to hexagons with the broad end posteriorly directed), or to an alternating arrangement of octagonal and quadrilateral elements. The literature reflects many of these variants, although in an incomplete and often anecdotal fashion, but records almost no attempts to hypothesize functional interpretations for the different neural bone configurations found among living turtles. In this paper, each of the major discrete neural configurations is correlated with other aspects of the anatomy, or with the behavior, of the species concerned.
