View - Kowalewski, M. - Virginia Tech

WALKER AND BRETT—POST-PALEOZOIC PATTERNS IN MARINE PREDATIONRepair scars that divert orcut across the normalconcentric growth lamellae(including: scallops,meandering clefts, divotedrepairs, and moreextensive repairs includingirregular fractures)Total number of repairscars on left valvesdivided by the totalsample size of repairedand uninjured valvesNo median recorded.Exogyra: 0.00–1.11*/0.40; Pycnodonte: 0.12–0.38/0.23Combined (Exogyra and Pycnodonte ) mean frequency: 0.34*Because more than one repair per shell was used, thefrequency can exceed 1.0.x, Campanian: 0.11; x, Maastrichtian: 0.44n =?528 or ?525 Exogrya spp., ?460 or ?450 Pycnodontespp. for Cretaceous localities, total ~?988; they state n = ">1600 indivs," 7 spp. (Paleocene + Cretaceous)As for bivalves As for bivalves 0.07–0.09/0.08; for all size classes, mean = 0.10 (from theirtable 5)n = ?77, 1 sp. Pycnodonta dissmilarisJagged repair scars onshellsNumber of individualswith one scar/totalindividuals of thatspeciesExcluding samples with 1 individual:0.03–0.59/0.29/no median (their table 10, p. 349–350)n = 3090 indiv.; 21 spp.Jagged repair scars onshellsAs for gastropods 0.07–0.35/0.21n=896, 2 spp. (corbulids had the highest shell repairfrequency at 0.35)Repairs were recordedonly if they extended 20%or more of the whole in aspiral direction or if theyinvolved subjectivelysubstantial breakage;excludes minor lip breaksNumber of repairedinjuries divided by thetotal number of shells inthe sample; frequencyof repair is looselycorrelated with thenumber of species ofshell-peeling calappidsMedian frequency reported (their table 1)*: Recent: n= 5735,0.54; Pleistocene: n =110, 0.55; Pliocene, n = 314, 0.54;Miocene, n = 549, 0.57; Paleogene, n = 136, 0.47* n must equal number of samples, but it is not clear; statedthat samples with ten or more individuals were used;frequencies of repair have remained unchanged from theEocene to PresentNo information; appears tobe large, jagged repairscars (his fig. 1)Frequency of snails withdamaged shellsestimated for eachpopulationMany localities, here totaled together: 0.00–0.48/0.11n = 4593(Table 3, cont.)Bivlaves: Osteids, Exogyra,PycnodonteLate Cretaceous (North AtlanticCoastal Plain, New Jersey)Dietl et al. (2000)Bivalves: Ostreids, Pycnodontesearly PaleoceneDietl et al. (2001)Gastropodslower Pliocene; Albenga, ItalyRobba and Ostinelli (1975)Bivalves: Anadara and Corbulaonlylower Pliocene; Albenga, ItalyRobba and Ostinelli (1975)Gastropods: TerebridsEocene–Recent; tropical tosubtropicalVermeij et al. (1981)Gastropods: LittorinidsRecent; cold temperateRafaelli (1978)133