Lindberg - 46

3a

21 2 2a a 3A 2a1 22 3B 2a12

1a22 1a2 1b 11 2b 22 21 2 21 11 1a 12 b 2a 2d 12 1a 2 1d 1a11 1

11 22 1d11 1b 22 1d2 1b2 3d 1d 1b 3b

11 12 12 1c 1b 2 1c 1c22 d 2 2d 1 1d 1 11 2 2 2 1 1 2 1 22 1c 2 2c 1c 2b 1c

2 12 c 2 1 2c 3D 2 2c 3C 21 2c 3c

Vetigastropoda Neritopsina Haliotis tuberculata Theodoxus fluviatilis

a2 3 3b ME2 2a 2 1

2a12 1a2 1 2b 1 2b 11 11 3a 1 3 2a b 2a 1a2 2 1d2 1a1

1 1 2 2d12 1d 1b 2b12 1d2 1b

2 1c1 1b2 1c 3 d 2d 2 2 1 1 d 1 1 1 11 2c 2c 12 2c 1c 2 3c 3d ME1 1 2c2 2 3c 4D Heterobranchia Sorbeoconcha Valvata piscinalis Crepidula fornicata

1q cell lineage 3q cell lineage Macromeres 2q cell lineage 4q cell lineage

FIGURE 8. Stylized embryo composition at the 32-36 cell stage in four gastropod subclades – Vetigastropoda (36 cells), Neritospina (36 cells), Heterobranchia (32 cells), and the Sorbeoconcha (34 cells). All cells are labeled in the Vetigastropoda; in subsequent diagrams only cells whose identity has changed relative to the vetigastropod condition are labeled. Cells are shaded to show affinities as cell lineage descendents, and pie charts summarize overall embryo composition for each taxon. Cell lineage data from van den Biggelaar and Haszprunar (1996).

Lindberg - 39

Patellogastropoda Sorbeoconcha

0 1q AB1q 20 1q1 1q1 11 11 1q 1q 40 A-D 2q 2q A-D 60 2q1 2q1 2q11 2q11 80 3q 1Q 3q 1Q 100 3q1 3q1 4q 4q 2Q 2Q 120 4d 4d 3Q 3Q 140

Original 4Q Original 4Q 160

180

D 1q C 1q 1 1 1q 11 1q 1q 1q11 2q A-D 2q A-D 1 2q1 2q 2q11 2q11 3q 1Q 3q 4q 1Q 1 3q1 4d 4q 3q 2Q 2Q 4d 3Q 3Q 4Q 4Q Dummy Dummy

cell number

11 11 E 1q F 1 1q 1q1 1q 1q 1q 2q11 2q11 1 2q1 2q 1 2q 3q 2q 3q1

3q 4Q 4d 3q 4Q 4d

Original Dummy

FIGURE 1. A-D. Cell lineage trees. Coding of cell lineage trees follows Conklin’s (1897) notation for the designation of cell lineages. Here q represents the micromeres a, b, c, and d, whereas Q = macromeres A, B, C, and D (see Lindberg and Guralnick [2003]). Landmarks used in this study are marked by •. A. Original coding of the cell lineage tree for the Patellogastropoda. B. Original coding of the cell lineage tree for the Sorbeoconcha. Note that in the original coding the y values for each cell lineage are constant. C. Randomized (dummy) coding of the y coordinates for the Patellogastropoda cell lineage tree. D. Randomized (dummy) coding of the y coordinates for the Sorbeoconcha cell lineage tree. Note that in the dummy coding both x and y coordinates vary. E-F. Procrustes superposition plots. E. Original data with linear variation around means. F. Dummy data with circular variation around means.

Lindberg - 40

Polyplacophora

Scaphopoda

Patellogastropoda

1 Vetigastropoda

Neritopsina 2

Sorbeoconcha 3 5 Architaenoglossa

4 Valvatoidea

6 Pulmonata

7 Opisthobranchia

FIGURE 2. Hypothesized gastropod relationships and nomenclature used for tpsTree analysis, and character and Procrustes distance mapping. Tree is based on a strict consensus tree of three maximum parsimony trees. For details and statistics see Ponder and Lindberg 1997: Table 2; fig. 3b. Consecutive numbers refer to hypothetical taxon units (or HTUs).

Lindberg - 41

1 2q11 3q 11 4Q 1q1 1q 2q1 4d 1q 2q 3q

FIGURE 3. Deformation grid showing transformation of cell lineage tree from one configuration to another as calculated by a generalized Procrustes analysis. In the above example the starting coordinates of each of the ten cell lineages are represented by the solid circles and the alteration to their relative positions in the next configuration is represented by the vector. Trends present in the original data were used to verify the direction of timing change (acceleration or retardation) relative to the compression and expansion patterns of each grid. Cell lineage originations that are accelerating between OTUs or HTUs produce compressions in the grid (2q11, 3q1, 4Q), while cell lineages that are decelerating between configurations cause expansion of the grid (1q1 and 1q11).

Scaphopoda

Patellogastropoda

Vetigastropoda

Neritopsina

Sorbeoconcha

Architaenoglossa

Valvatoidea

Opisthobranchia

Pulmonata

FIGURE 5. Deformation grids for eight major gastropod subclades, the outgroup Scaphopoda, and internal nodes plotted on the Ponder and Lindberg (1997) hypothesis of gastropod phylogeny. Reconstruct character states at HTUs calculated under maximum parsimony, accelerated transformation, and Dollo character ordering assumptions (see Table 1 for values). Lindberg - 44

A 0.08 C 0.08 Veti Arch 0.06 Opist Sorb 0.06 Val

0.04 Veti 0.04 Pul Pat Scaph 0.02 0.02 HTU2 HTU3 Pul HTU6-7 0.00 0.00 HTU4-5 Nerit Opist Pat -0.02 Nerit -0.02 Val -0.04 -0.04 Sorb

-0.06 Arch Poly -0.06 Scaph HTU1 -0.08 -0.08 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 -0.10-0.08-0.06-0.04-0.020.000.020.040.060.080.10 B 0.08 D 0.08 Veti Arch Val Arch 0.06 0.06 Val 0.04 Veti 0.04 0.02 0.02 Opist Pul HTU2 0.00 HTU3 Pul HTU6-7 0.00 HTU4-5 -0.02 Opist Nerit Nerit -0.02 Pat -0.04 Sorb Pat Sorb -0.04 -0.06 Scaph -0.08 -0.06 Scaph HTU1 -0.10 -0.08 -0.12 -0.10 -0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 -0.10-0.08-0.06-0.04-0.020.000.020.040.060.080.10 PCA 1 PCA 1

FIGURE 6. Principal component (PC) analysis of partial warp scores based on a generalized least squares Procrustes analysis of cell lineage data. A. Polyplacophora representing outgroup with implied change in PC space between Polyplacophora and Heterobranchia taxa. B. Scaphopoda as sole outgroup with deformation grids representing implied change in PC space between Scaphopoda and Vetigastropoda (right) and Scaphopoda and Heterobranchia taxa (left). C. Scaphopoda as outgroup with deformation grids representing implied change in PC space between Scaphopoda and Vetigastropoda (left) and Scaphopoda and Heterobranchia taxa (right). D. Same as C, but with deformation grid representing implied change in PC space between Valvatoidea and Architaenoglossa taxa and their sister taxa Sorbeoconcha and Opisthobranchia+Pulmonata respectively. Outgroups = ■, Ingroups = ●, and HTUs = ○.