Bipolar variation inClione, a gymnosomatous pteropod

• Other Authors: Gilmer, R. W., Lalli, C. M., Harbor Branch Oceanographic Institute
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Malacological Union
• Subjects: Clione; Gymnosomata; Clione limacina; Arctic; Antarctic; The Antarctic; Pacific; Antarc*; Antarctica; Limacina helicina; North Atlantic
• Online Access: http://purl.flvc.org/fau/fd/FA00007403; https://fau.digital.flvc.org/islandora/object/fau%3A33057/datastream/TN/view/Bipolar%20variation%20inClione,%20a%20gymnosomatous%20pteropod.jpg

The gymnosome Clione inhabits waters of the Arctic, North Pacific, North Atlantic, South Atlantic and Antarctic Oceans. This study reexamines bipolarity in this genus, utilizing new morphological techniques as well as observations of living animals in all locales. Differences in exernal anatomy are readily apparent in both larval and adult Clione from northern and southern areas, and scanning electron microscopy has revealed differences in the number and size of hooks in animals from different regions. The configuration of the radula differs between specimens from the northern and southern hemispheres, and Clione from the Antarctic lacks median radular teeth, in contrast to the well developed, sickleshaped median teeth present in C/ione from northern areas. Clione acts as a food specialist throughout its range, feeding either on the bipolar thecosome species Limacina helicina (Phipps) in cold waters or L. retroversa (Fleming) in temperate waters. Differences in maximum adult size of Clione can be related to the size of available prey. Although there do not appear to be differences in the feeding behavior of Clione from different areas, there are slight differences in swimming and escape behavior, particularly between specimens of Clione from northern and southern regions. The results of these anatomical and behavioral observations support the validity of recognizing two species of Clione, C. limacina (Phipps) in the northern hemisphere and C. antarctica (Smith) in the Antarctic and South Atlantic oceans. Florida Atlantic University. Harbor Branch Oceanographic Institute contribution 749 This manuscript is an author version with the final publication available and may be cited as: Gilmer, R. W., & Lalli, C. M. (1990). Bipolar variation in Clione, a gymnosomatous pteropod. American Malacological Bulletin, 8(1), 67-75.