Gunnar Thorson's world-wide collection of prosobranch egg capsules: Melongenidae

• Published in: Ophelia Vol. 46; no. 2; pp. 83 - 125
• Main Author: D'Asaro, Charles N.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.05.1997
• ISSN: 0078-5326
• DOI: 10.1080/00785326.1997.10432578

Spawns (masses of encapsulated, fertilized eggs or embryos) from 12 melongenid species representing six genera including Busycon; Busycotypus, Hemifusus, Melongena, Pugilina, and Volema, are described, illustrated, and compared. Egg masses produced by melongenids are structurally similar and can be divided into two general categories based on the method used by spawners to attach capsules to a substratum. The first includes vasiform envelopes with overlapping basal layers and little ornamentation that are cemented in a row on a firm substratum. The second, probably derived from the first, involves the folding of overlapping basal layers to form a string-like attachment joining capsules in a single row. In the latter category, one end of the mass is anchored in a soft, particulate substratum by several structurally modified capsules usually devoid of embryos. Melongenids, which typically have slow, direct development, do not exhibit an array of sculptural features on their egg capsules that could be considered antipredatory devices. Spawns from species in five of the genera studied appear to be species-specific, but insufficient information concerning Hemifusus prevented any conclusion from being made about the uniqueness of spawn in that genus.