OBSERVATIONS ON THE REPRODUCTION OF Bifurcium bicanaliferum (SOWERBY, 1832) FROM THE PACIFIC COAST OF PANAMA (GASTROPODA, COLUMBELLIDAE, STIWMBINA GHOUP).

FORTUNATO H.; PENCHASZADEH, P. E.; MILOSLAVICH, P. A.; ALVAREZ, M.

Hilo, Hawai

Encuentro; American Malacological Union, 61st. Annual Meeting, Hilo, llawai 'i. 1995; 1995

University of Hawai´i at Hilo

Bifurcium bicanaliferum is the only living species of the genusand it is a Pacific restricted spccics, The egg capsules are deposítedattached to the adult shcll, In cach cgg capsule a mean of 25 eggsmeasuring ISO rnicrons in diarnctcr are deposited. There are nonurse eggs; neverthclcss thcrc is evidcnce of late intracapsularcannibalism. Hatching takcs as a free veliger which survives as aswimming larva for al least 10 days in the aquariurn. Thc shelllength at hatching is 232 rnicrons and presents I '1, volutions. Giventhat the protoconch of the adult consists 01' 2 '1, volutions, i¡ seemsthat an important planktonic pcriod 01' lime must be cornpleted. Themode of developrncnt of this spccics was previously infercd byJackson et al. (in prcss) by using the rclationship betwccn themaximum diameter 01' the adulr's protoconch and it's maximumnumber of volutions. Our results with live material corroborate theplanktonic mode 01' developmcnt. A comparison of the reproductivepattern of Bifurcium with two Caribbean Strombina whích have alower number of bigger eggs pcr egg capsule and directdevelopment (Cipriani and Pcnchaszadeh, 1993, The Veligcr, 36:178-184) show striking differences in their reproductive parterns.