View - Kowalewski, M. - Virginia Tech

VERMEIJ—EVOLUTION IN THE CONSUMER AGEDivalinga quadrisulcata, Alexander and Dietl(2001) demonstrated a decreasing effectivenesswith increasing latitude from the tropical FloridaKeys to New Jersey. They found no pattern inAnadara ovalis, a species in which drilling isalmost always successful. These and other datasupport the point that evolutionary trends relatedto escalation must be evaluated within lineages orwithin adaptive syndromes from physically similarenvironments.Confirmed living marine perpetrators that drilltheir prey are mainly gastropods (Naticidae,Cassidae, Muricidae, some Marginellidae, and thedorid nudibranch Okadaia) and octopodcephalopods (Vermeij, 1987; Kabat, 1990; Ponderand Taylor, 1992). The gastropods generally attackother molluscs as well as barnacles, ostracodes,tube-dwelling polychaetes, benthic foraminifers,and even ascidians; but cassids specialize onechinoderm prey. Edge-drillers are known onlyamong polinicine naticids and various muricids(Vermeij, 1987). Octopods attack molluscs anddecapod crustaceans (Boyle and Knobloch, 1981;Dodge and Scheel, 1999).Times of first appearance of these moderndrillers are not well constrained. Undoubted naticidsare known from the earliest Cretaceous(Valanginian) onward (Riedel, 2000), but someauthors would extend their range back to the Carnianstage of the Late Triassic based on thecharacteristically beveled shape of drill-holes of thatage in bivalves from the St. Cassian Formation ofnorthern Italy (Fürsich and Jablonski, 1984). Itshould be noted, however, that beveled holes alsooccur in Paleozoic brachiopods (Smith et al., 1985),and that such holes even today are occasionallydrilled by muricids (Gordillo and Muchástegui,1998). Muricids are known from the Late Cretaceous(Campanian) onward (Merle and Pacaud, 2001), butmay extend back to the late Early Cretaceous(Albian) based on cylindrical holes in Britishbivalves of that age (Taylor et al., 1983). Undoubtedcassids date from the Late Cretaceous(Maastrichtian) (Riedel, 1995), but most drill-holesin echinoderms, presumably made by cassids, areof Cenozoic age. Drill-holes in Maastrichtianechinoids could be the work of parasitic eulimidgastropods (Kier, 1981). Marginellids appeared inthe Paleocene (Coovert and Coovert, 1995), but itis unclear when drilling members of this groupevolved. Octopods have a Jurassic origin, but againwe do not know when octopod drill-holes appear.The identity of pre-Cretaceous drillers remainscontroversial. Platyceratid gastropods, many ofwhich lived on and parasitically drilled Paleozoicechinoderms, may well be responsible for drillholesobserved in Paleozoic brachiopods(Baumiller, 1990, 1993, 1996; Baumiller andMacurda, 1995; Baumiller et al., 1999;Kowalewski et al., 2000; Leighton, 2001). Therewere no gastropods in the late Neoproterozoic orEarly Cambrian. The architects of drill-holes ofthese ages thus remain entirely unknown.Shell drilling, or at least shell puncturing, alsooccurs in land snails. The culprits appear to be variouskinds of beetles. The only systematic survey of thephenomenon is that of Ørstan (1999), and nothing isknown about the history of terrestrial drilling.Shell repair, much of it likely a response toskeletal injury by predators, has generally increasedin incidence through Phanerozoic time (Vermeijet al., 1981). The oldest known examples ofrepaired gastropod shells date from the late MiddleOrdovician (Caradoc) of Sweden (Ebbestad, 1998;Ebbestad and Peel, 1997). The number of repairsper shell in the limited Caradoc and Ashgill (LateOrdovician) fossils examined by Ebbestad and Peel(1997) was only 0.07, a very low value by LateCretaceous to Recent standards. Data from wellpreserved Late Carboniferous, Late Triassic, andEarly Cretaceous gastropods indicate higherincidences, but still are not up to the standards ofthe Late Cretaceous, late Miocene, and Recent(Vermeij et al., 1981; Pan, 1991). Sparse data ongastropods of the broadly circumscribed genusConus indicate that Miocene, Pliocene, and Recentspecies show higher frequencies of repair thanEocene species (Vermeij, 1987). Data on Cenozoicturritellid gastropods from the southeastern UnitedStates and tropical America (Allmon et al., 1990)reveal no general trend, although repair was rare inthe early Oligocene species examined. I re-385