Gastropod predation patterns in Pliocene and Recent pectinid bivalves from Antarctica and New Zealand

Abstract

Boreholes in the large, extinct Antarctic Neogene pectinid Zygochlamys anderssoni suggest that this scallop was preyed upon by a large predatory muricid gastropod i possibly a Trophon species). The holes occur in mature individuals, which contrasts with the situation in modern Zygochlamys delicatula from New Zealand, where gastropod predation is apparently restricted to juveniles only. This difference is ascribed to dissimilarities in the lifestyles of these scallops; whereas the former was probably byssally attached throughout ontogeny, adults of the latter become tree living after an initial period of byssal attachment. During the late Pliocene, a change towards higher motility in Chlamys-like pectinids of the Southern Ocean may have caused the loss of an important food source for the larger muricids.

Effect of durophagy on drilling predation: a case study of Cenozoic molluscs from North America

“…For example, some studies have used such data to compare predation intensities between different areas during the same (or nearly the same) temporal span (Jonkers 2000;Leighton 2001;Walker 2001;Baumiller and Bitner 2004), while others have used them to analyse temporal trends in predation intensity (Sohl 1969;Dudley and Vermeij 1978;Taylor et al 1983;Allmon et al 1990;Hagadorn and Boyajian 1997;Harper et al 1998;Leighton 2003;Amano 2006;Kelley and Hansen 2006). Although it is recognised that such frequencies may be influenced by extrinsic factors, in general they are interpreted in the context of predator and prey only.…”

Reworked late Neogene Austrochlamys anderssoni (Mollusca: Bivalvia) from northern James Ross Island, Antarctica

“…In another (DJ.1501.5; VH c. 125 mm) VH was estimated from projection onto a specimen with known valve height (DJ.851.4 from Cockburn Island). Valve height of other specimens was computed from the length of the outer ligament (OL, n 5 5), length of the anterior outer ligament (OLA, n 5 9), or length of the posterior outer ligament (OLP, n 5 9), using the regression equations given for A. anderssoni by Jonkers (2000). It appears that the majority (64%, n 5 25) of identifiable valves fall within a size range of VH 100-110 mm (Fig.…”

“…VH, OL, OLA, OLP, BND in mm; UA, UAA, UAP in degrees; BT dimensionless. VH was computed using regression equations inJonkers (2000), all other values from actual measurements and counts.…”

Revision of Southern Hemisphere taxa referred toFosterella(Crustacea: Cirripedia), and their extinction in response to Pleistocene cooling

“…Other predators that co-existed with Fosterella and Porobalanus include muricid gastropods. According to Jonkers (2000), these boring gastropods targeted bivalves, at least up to the end of the Pliocene, at which time Zygochlamys is likely to have developed a high motility lifestyle, thus avoiding predation (Jonkers 2000). This would have increased predation pressure on the sessile barnacles.…”