View - Kowalewski, M. - Virginia Tech

PALEONTOLOGICAL SOCIETY PAPERS, V. 8, 2002The gonodactyloids can smash small to largeholes in molluscan prey (Hof, 1998; Ahyong andHarling, 2000). Stomatopods can also sheargastropod shells in half and break the outer lip(Geary et al., 1991). Additionally, small puncturewounds in molluscan prey, called ballistic traces(e.g., the trace fossil Belichnus), are attributed tostomatopods (Pether, 1995). Most of the extantgroups have an actual fossil record extending backonly to the Eocene, with the shell-smashinggonodactylid group originating in the Miocene(Hof and Briggs, 1997; Hof, 1998). Approximately400 living stomatopod species are recognized(Manning, 1995).Despite their long history, only a few examplesof gonodactylid shell-breaking predation areknown from the Neogene fossil record. Geary etal. (1991) described a few cases of putativestomatopod shell damage from Pliocene localitiesin Florida. Baluk and Radwanski (1996) alsodocumented stomatopod damage on diversegastropods from Miocene localities in Europe.Stomatopod predatory damage should be easilyrecognized, and documentation of this damage inmore assemblages would enhance thepaleoecological picture of these creatures.Brachyuran crabs and lobsters.—The secondmajor wave of crustacean adaptive radiationoccurred in the Paleogene. Brachyuran crabs hadappeared in the Mesozoic, but new families of crabssuch as the Portunidae, Cancridae, Grapsidae, andOcypodidae arose in the Eocene (Table 1). Mostbrachyuran crabs are generalist and opportunisticfeeders, and few are durophagous (Table 1).Brachyurans with heavily toothed claws apparentlyevolved in the Paleocene (Vermeij, 1983), but thishas not been studied in detail. Crushing claws area formidable tool for peeling and crushingmolluscan shells and also for crushing othercrustacea or hard-shelled prey. The distinctivepeeling of calappid crabs has been documented infossil and recent shells (Bishop, 1975; Vermeij,1982, 1987). The parthenopid crabs, whichoriginated in the Late Cretaceous, are known toeat molluscs only in the laboratory (Vermeij, 1978),and the few reports available show them eatingpuffer fish or non-molluscan invertebrates(Table1). Clearly more work needs to be done onthe parthenopid crabs. Durophagous cancrid crabs(Cancer spp.) eat a diversity of prey, such aspolychaetes, squid, crustaceans, fish, andechinoderms, following the dominant macroinvertebratesin the habitat; whereas Ovalipid crabsmay predominantly eat molluscs (Stehlik, 1993).Lobsters also crush shells, but usually onlyfragments are left (Cox et al., 1997). In modern seas,rock lobsters are known to prey extensively onmolluscs, such as abalones and turban snails in somelocalities (Van Zyl et al., 1998; Branch, 2000), andechinoderms in others (Mayfield et al., 2001). Verylittle is known about lobster foraging and how it wouldaffect the fossil record of invertebrate hard-shelledprey (reviewed in part by Walker et al., 2002).Gastropods.—Gastropod predators that chipand wedge open molluscan prey (e.g., Buccinidae,Fasciolaridae, and Melongenidae) originated in theLate Cretaceous, but diversified in the Cenozoic;however, the shell-chipping record in prey shellsis known only from the Pliocene (Vermeij, 1987).Buccinid gastropods chip their outer lips in theprocess of preying on other mollusks, and thensubsequently repair their self-inflicted breakage(Carriker, 1951; Nielsen, 1975). Dietl and Alexander(1998) noted that this type of lip damage occurs inbuccinids as old as Miocene. Older buccinids, whichrange back to the Late Cretaceous, have not yieldedevidence of this distinctive lip damage. Hence, theshell-prying habit of buccinids may have evolvedwithin the Neogene.The best evidence for predation in the Cenozoicfossil record comes from predatory drillholespreserved in prey ranging from protists, such asforaminifera, to many phyla of invertebrates, suchas bryozoans, molluscs, brachiopods, andechinoderms (Carriker and Yochelson, 1968; Sohl,1969; Taylor, 1970; Sliter, 1971; Bishop, 1975;Boucot, 1981, 1990; Bromley, 1981; Vermeij, 1987;Kabat, 1990; Kowalewski, 1993; Kowalewski andFlessa, 1997). Prosobranch gastropods are theprimary shell drillers in marine environments,although nudibranchs (Vayssiereidae), flatworms,nematodes, and the protist foraminiferans have also154