Developmental dynamics of myogenesis in the shipworm Lyrodus pedicellatus (Mollusca: Bivalvia)

Table 1 Larval myogenesis in Lyrodus pedicellatus

Muscles		Stage 1	Stage 2	Stage 3	Stage 4	Stage 5	Stage 6	Stage 7	Stage 8
Ventral larval retractor		+	-	-	-	-	-	-	-
Velum ring musculature		+	+	+	+	+	+ / -	-	-
Dorsal velum retractor		+	+	+	+	+	+	-	-
Ventral velum retractor		+	+	+	+	+	+	+ / -	-
Anterior adductor		+	+	+	+	+	+	+	+
Foot retractor	anlage + → median fusion ++ → prolongation +++ → fusion with pedal plexus and accessory foot retractor ++++	-	+	++	+++	+++	++++	++++	++++
Pedal plexus	anlage + → expansion ++ → fusion with foot retractor and accessory foot retractor +++	-	-	-	+	++	+++	+++	+++
Oral velum musculature		-	-	-	+	+	+ / -	-	-
Accessory velum retractor		-	-	-	+	+	-	-	-
Posterior adductor		-	-	-	-	+	+	+	+
Accessory foot retractor		-	-	-	-	-	+	+	+
Accessory adductor		-	-	-	-	-	+	+	+
U-shaped mantle musculature		-	-	-	-	-	+	+	+
Finger-shaped mantle musculature		-	-	-	-	-	-	+	+
Dorsal mantle musculature		-	-	-	-	-	-	+	+
Lateral mantle musculature		-	-	-	-	-	-	- / +	+

character: (+) present; (-) absent; (+/-) decreasing; (-/+) increasing.
stage 1 = earliest veliger investigated; stage 2 = early veliger; stage 3 = mid-veliger 1; stage 4 = mid-veliger 2;
stage 5 = late veliger; stage 6 = mid-pediveliger; stage 7 = late pediveliger; stage 8 = early juvenile.

ISSN: 1742-9994