Myogenesis of Malacostraca – the “egg-nauplius” concept revisited

Table 1 The table gives a list of all muscle precursors described and discussed throughout the paper

Body region	Muscle precursor group	Appendage anlage/segment	Muscle precursor
Stomodeal region	Stomodeal precursor group	-	st
		-	st-1
		-	st-2
		-	st-3
		-	ppg
Appendage anlagen (distal region)	Intrinsic precursors	-	Intr
Appendage anlagen (proximal region)	Medial extrinsic precursors	A1	a1-m
			a1-m1
			a1-m2
		A2	a2-m
			a2-m1
			a2-m2
		Md	md-m
		Mx1	mx1-m
			mx1-m1
			mx1-m2
		Mx2	mx2-m
			mx2-m1
			mx2-m2
			mx2-m3
		T1	t1-m
			t1-m1
			t1-m2
	Lateral extrinsic precursors	A2	a2-l1/2
			a2-l1
			a2-l2
		Md	md-l1
			md-l2
			md-l3
			md-l3/mx1-l1
		Mx1	mx1-l1
			mx1-l2
			mx1-l3
		Mx2	mx2-l/t1-l
			mx2-l1
			mx2-l2
			mx2-l3
		T1	t1-l1
			t1-l2
Trunk region	Longitudinal precursors (lmp)	Md	lmp-md
		Mx1	lmp-mx1
		Mx2	lmp-mx2
		T1	lmp-t1
		All segments (dorsal region)	lmp-d
		Growth zone/telson	lmp-post

Muscle precursor terms represent a code of letters and numbers, given in italics, which relate to the body region (e.g. stomodeum st) appendage anlage or body segment (e.g. first antenna a1). It also refers to the anteroposterior arrangement of precursors from anterior to posterior (numbers). Muscle precursors are sorted into groups by appendage/segment affiliation (A1, A2, etc.), muscle precursor group (stomodeal precursor group, intrinsic appendage muscle precursors, medial extrinsic appendage muscle precursors, lateral extrinsic appendage muscle precursors, longitudinal trunk muscle precursors), and body region (stomodeal region, distal region of appendage anlage, proximal region of appendage anlage, trunk region). Certain precursors (a1m, mx1-m, mx2-m and t1-m) give rise to multiple precursors found at later stages (e.g. a1-m gives rise to a1-m1 and a1-m2) but the way this is achieved is uncertain (there are three possibilities: a precursors splits into two precursors, an additional precursor arises at a more anterior position, or an additional precursor arises at a more posterior position). Three precursors (a2-l1/2, md-l3/mx1-l1, mx2-l/t1-l) give rise to two different muscle units each (a2-l1, a2-l2; mx2-l, t1-l and md-l3, mx1-l1, respectively).

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