We report on three separate instances of protrusion of the valvular intestine in the smalltooth sawfish Pristis pectinata, compare pristid gastrointestinal anatomy and intestinal valve structure with those of other elasmobranchs, and discuss the relevance of anatomy and valve structure to the husbandry of captive specimens. Protrusion of the valvular intestine, or intestinal eversion, has been documented in carcharhinid sharks with scroll-type intestines. All three cases of protrusion in smalltooth sawfish in this report involved specimens in multispecies display facilities and ultimately resulted in mortality. These are the first documented cases of intestinal eversion in any species of elasmobranch with a conicospiral valvular intestine. The valvular intestine of sawfishes (family Pristidae) is of the conicospiral type, which is similar to that described in other batoid species. However, unlike many other sharks and batoids, which possess short, stout pyloric stomachs, the pyloric stomachs in the pristids we examined were long and similar to those of carcharhinid sharks. The ability to protrude the valvular intestine in elasmobranchs may depend upon both valve morphology and the length of the pyloric stomach. The details of the gastrointestinal anatomy may be useful for systematics but also may be relevant to the captive husbandry of carcharhinids and sawfishes.
ASJC Scopus subject areas
- Aquatic Science