Reproduction of Crepidula navicula Mørch, 1877 and Crepidula aplysioides Reeve, 1859 (Caenogastropoda) from Morrocoy and La Restinga Lagoon, Venezuela

MILOSLAVICH, PATRICIA; KLEIN, E.; P. E. PENCHASZADEH

THE NAUTILUS (PHILADELPHIA)

BAILEY-MATTHEWS SHELL MUSEUM

Lugar: Philadelphia; Año: 2003 vol. 117 p. 121 - 134

0028-1344

Brooding specimens of Crepidula aplysioides and Crepidula navicula were collected from La Restinga Lagoon, Margarita Island and Las Luisas Bay, Morrocoy, Venezuela at a depth of 0.5-1 m. Individuals of C. aplysioides were attached to mangrove oysters and mussels that were attached to the roots of Rhizophora mangle, while those of C. navicula were attached to the gastropod Modulus modulus. Brooding females of C. aplysioides measured 9.4-18.2 mm shell length and each female brooded 23.4 ± 4.5 egg capsules. The egg capsules had a triangular shape, with one corner extending to form a stalk that attached the egg capsule to the substrate. The capsule walls were thin and transparent. Egg capsules measured 0.5-2.1 mm length (without the stalk), 0.7-2.7 mm width, and the stalk 0.6-3.3 mm length. The number of eggs per capsule varied from 3 to 18. The uncleaved egg measured about 300 μm and all eggs developed. Nurse eggs were not observed. Cannibalism, however, was observed among sibling embryos and the number of hatchlings was significantly lower (by one individual) than the number of eggs. Hatching occurred as crawling juveniles measuring about 600 μm in shell length. Brooding females of C. navicula measured 4.9-7.4 mm shell length and each female brooded 8.5 ± 2.2 egg capsules. The egg capsules were very similar to those of C. aplysioides but smaller (between 0.5 and 1.3 mm lengthwise) and contained 3-6 eggs each. The uncleaved eggs measured around 330 μm. All eggs develop; cannibalism was observed and the number of hatchlings was significantly lower than the number of eggs. Between 2-4 individuals hatched per capsule as pediveligers measuring 550-1172 μm shell length. Female size determined fecundity, in terms of juvenile production, on both species. This is accomplished through two different strategies, the first an increase in the number of hatchlings per female at larger female sizes (C. aplysioides) and the second that larger females produced larger egg capsules with more hatchlings (C. navicula).