ABSTRACT
Sexual dimorphism correlates with a number of behavioral attributes, some of which can be recognized in the fossil record, as noted below for placental mammals (Kurten, 1969), and even for some fossil reptiles (Olson, 1969). Sullivan et al. (2003) invoked sexual dimorphism to explain some aspects of the dentition of a South African Permian cynodont (Diictodon). Størmer (1969) described dimorphism, presumably sexual, in eurypterids and pointed out that it is unclear which dimorphs are male as contrasted with female. The potential for sexual dimorphism in ammonoid cephalopods has been recognized since the 19th century (see Davis et al., 1969; other papers in Westermann, 1969; Lehmann, 1966; for another review with good illustrations of varied forms, including putative females with lappets, see Makowski, 1962). Etter (2004) briey reviewed sexual dimorphism in tanaidacean crustaceans. Sexual dimorphism is widespread among varied decapods (Feldmann, 1998, 2003; Feldmann and de Saint Laurent, 2002; Schweitzer, 2003; Schweitzer Hopkins and Feldmann, 1997). Feldmann (1998, Figure 3) provided truly elegant views of male, female, and castrated male ventral abdominal development in some New Zealand Miocene crabs (see also Section 4AIo, Rhizocephalan-Decapod Parasitism). Sexual dimorphism is, of course, widespread among varied spider and insect taxa preserved in amber. Stubbleeld and Seger (1994) commented extensively on varied evidence for sexual dimorphism in different hymenopteran groups.
