FIGURE 3. Copy of a portion of the outgroup analysis in Wagner (1997, figure 3), showing the inferred relationships between Mellopegma and Eurekapegma ('pararostroconchs' sensu Runnegar 1978), disputed rostroconchs (Watsonella, Pseudomyona, Tuarangia) and undisputed rostroconchs. See text for details. Letters indicate character transitions that are here added to Wagner's (1997) cladogram; see key below. The characters are derived from Wagner's data matrix (www.treebase.org), using the most parsimonious character distribution on his majority-rule consensus cladogram. Key: a, posterior trend projected adapically; b, posterior extension (rostrum) and aperture behind vector from apex; c, posterior gape; d, greatest width not at aperture; e, 2 valves; f, denticles; g, 2 valves; h, H:W=4; i, loss of denticles.